A piezoelectric device includes a lower electrode, a piezoelectric film and an upper electrode laminated in this order on a support. An oxide film containing a material that forms a lower electrode is formed on a side surface of the piezoelectric film. The piezoelectric device is produced such that an upper electrode and a piezoelectric film are patterned by dry-etching through a mask formed on a side of the upper electrode of the piezoelectric device member and thereafter a side surface of the patterned piezoelectric film (a film adhered to a side wall) is oxidized to form an oxide film.

1. Field of the Invention
The present invention relates to a piezoelectric device and a method of production thereof.
2. Description of the Related Art
In inkjet heads, piezoelectric bodies and semiconductor devices such as FeRAMs and MRAMs, a piezoelectric film, a magnetic body and an electrode material such as platinum are used (refer to, for example, Japanese Patent Application Laid-Open (JP-A) Nos. 10-211701 and 2007-276384). These are called "hard-to-etch" materials and are difficult to process. In general, when a hard-to-etch material is processed, a dry etching process is frequently used. When a hard-to-etch material is etched, a gas containing halogen is frequently used. Examples of the gas containing halogen include mixed gases containing halogenous gases such as fluorine-based gases or chlorine-based gases and the inert gas argon, and mixed gases containing fluorine-based gases and chlorine-based gases.
When a piezoelectric film is dry etched, a resist is patterned on an etching surface to form a mask and dry etching is applied through the resist mask, whereupon a reaction product is generated at the time of etching which is non-volatile and tends to adhere to a side surface of the mask.
Furthermore, if over etching is performed, a lower electrode is sputter-etched and tends to adhere to a side wall of the patterned piezoelectric film. In this case, a film is formed by material adhering to a side wall of the piezoelectric film due to etching of a lower electrode (a film adhered to side wall). This film is electroconductive, and a leak current between a lower electrode and an upper electrode is therefore problematic. Various methods have been proposed to inhibit the upper and lower electrodes from short-circuiting due to the film adhered to the side wall.
JP-A No. 2000-22090 discloses a method in which, when an upper electrode, a ferroelectric material and a lower electrode are dry-etched, the upper electrode is dry-etched with an oxide film mask, an oxide film mask and a resist mask for the ferroelectric material and lower electrode are formed so as to cover the remaining oxide film mask, and the ferroelectric material and the lower electrode are then etched.
JP-A No. 2000-183287 discloses a method in which an inert gas and a halogen gas are used to etch a dielectric film formed on a lower electrode up to the middle thereof, followed by etching the remaining dielectric film and over-etching the lower electrode with only halogen gas, further followed by cleaning with a peeling agent such as water or hydrochloric acid to remove a residue generated by the etching.
JP-A No. 8-181126 discloses a method where, after an anti-etching mask is formed with SOG (Spin On Glass) or the like on a ferroelectric film such as PZT (lead zirconate titanate), an inert gas and a halogen gas are used to perform dry etching and a deposit adhered to a side wall of the ferroelectric film during etching is removed with water or the like.
According to the method disclosed in JP-A No. 2000-22090, an etching mask is formed a plurality of times and an upper electrode and a dielectric material are separately etched; accordingly, processing becomes complicated and costs increase greatly due to an increase in processing steps.
According to the method disclosed in JP-A No. 2000-183287, when a strong acid or a special peeling agent is used, a lower electrode and a dielectric film may be damaged. On the other hand, when water is used, a film adhered to a side wall may not be sufficiently removed.
According to the method disclosed in JP-A No. 8-181126, the processes involved in forming a mask increase because a hard mask is formed from SOG (or the process of forming a mask becomes complicated), and it is also difficult to remove a mask after etching.

Piezoelectric device and method of production thereof


An image processor that can suitably specify a predetermined area of a grayscale image is provided. An extreme value coordinate acquiring unit performs scanning on at least one of a plurality of pixels including a target pixel from the target pixel in accordance with gradient information corresponding to a change in a pixel value, and acquires a coordinate of the scanned pixel corresponding to an extreme value of the pixel value as a coordinate of an extreme value pixel corresponding to the target pixel. An area specifying unit labels each target pixel with an area identification mark used for specifying an area to which the each pixel belongs. The area specifying unit 103 labels each of different pixels corresponding to coordinates of extreme value pixels located close to each other within a particular range with an area identification mark indicating an identity of the area to which the pixels belong. Accordingly, the area to which each pixel belongs is able to be specified based on the area identification mark.

An example of a conventional cell recognition processing is disclosed in Patent Document 1. According to the cell recognition process, a cell shape is superimposed on an image obtained by imaging a cell, and a position of a cell center is thereby extracted; pixel candidates defining a borderline of the cell are selected based upon a degree of coincidence of a direction of a luminance gradient of each pixel around the cell center and a direction toward the cell center from the each pixel; and a dynamic borderline is extracted using information on a magnitude of the luminance gradient corresponding to a position of the selected pixel candidates, thereby acquiring the borderline of the cell in detail.
The cell recognition process will be described in detail, focusing on its features. First, a method using a circular shape as a model for the cell shape is used to detect the cell center. Specifically, every cell within the image is subject to the following process performed such that, the luminance gradient direction of each target pixel within the image is calculated; and a pixel position which is a predetermined radius away in the gradient direction from the target pixel is given a point. As the result of such a process, the position where the luminance gradients which are a predetermined radius away from the periphery concentrate scores high points and is regarded as the cell center. Next, the borderline pixel candidate is selected based on the fact that the luminance gradient of the cell borderline is directed toward the cell center. The borderline pixel candidate is selected based upon a mathematical sign corresponding to an inner product of a luminance gradient vector of the target pixel located around the cell center and a displacement vector directed toward the cell center from the target pixel. In a dynamic borderline extraction process, a circular closed curved line of a specified radius around the cell center is set. If the closed curved line is on the borderline pixel candidate, the magnitude of the luminance gradient for the position of this pixel is subtracted. Such subtraction is performed for the entire closed curved line in order to attain an evaluation value. This evaluation value is minimized where the closed curved line coincides with the borderline candidate pixel to the greatest degree. Accordingly, while the shape of the closed curved line is partially changed, other evaluation values are repeatedly obtained in the same manner. The closed curved line when the obtained evaluation value is the smallest is regarded as a final cell borderline.
Examples of an area dividing method used for extracting a target area within an image include the Watershed algorithm (see Nonpatent Literature 1). The Watershed algorithm is a method for dividing an image, such as to divide an image by a boundary that is formed between different hollows where water stays when filling water into a topography regarding image grayscale information (e.g., luminance) as altitude.
FIG. 33A to FIG. 33D are diagrams explaining a principle of a process of the Watershed algorithm. FIGS. 33A to 33D show a one-dimensional example for simplified explanation. Firstly, a pixel having a minimum value is detected from luminance data of an image, as shown in FIG. 33A. Here, the pixel having the minimum value refers to a pixel having a luminance of which is the lowest among adjacent pixels. Next, as shown in FIG. 33B, areas are expanded from the minimum value in a similar manner as water stays in the hollows of luminance. In the expansion process, a boundary (Watershed) is formed at a position where areas expanded from different minimum values meet with each other, as shown in FIG. 33C. Finally, as shown in FIG. 33D, the image is divided by the boundary formed when the quantity of water held is greater than the maximum luminance. In the example shown in FIG. 33D, the image is divided into areas A, B, C and D by the forgoing process.
Meanwhile, there are two concepts of adjacent pixels in a two-dimensional grid image: one is a four adjacent pattern (refer to FIG. 34A) in which the target pixel in the middle has four adjacent pixels in the vertical and horizontal directions; and an eight adjacent pattern (refer to FIG. 34B) in which the target pixel in the middle has eight adjacent pixels in the vertical and horizontal directions and in the diagonal directions. The processes of detecting minimum values and expanding areas are carried out in accordance with either one of the concepts.    Patent Document 1: Japanese Patent No. 3314759.    Nonpatent Literature 1: Luc Vincent and Pierre Soille. Watersheds in digital spaces: An efficient algorithm based on immersion simulations. Transactions on Pattern Analysis and Machine Intelligence, Vol. 13, No. 6, pp. 583-598, June 1991.

Image processor, microscope system, and area specifying program


A process for forming a tetra(aryl)-biphenyldiamine compound, including reacting a dibromobiphenyl compound and a diarylamine compound in the presence of a palladium ligated catalyst and a base.

In electrophotography, an electrophotographic substrate containing a photoconductive insulating layer on a conductive layer is imaged by first uniformly electrostatically charging a surface of the substrate. The substrate is then exposed to a pattern of activating electromagnetic radiation, such as, for example, light. The electromagnetic radiation selectively dissipates charge in illuminated areas of the photoconductive insulating layer while leaving behind an electrostatic latent image in non-illuminated areas of the photoconductive insulating layer. This electrostatic latent image is then developed to form a visible image by depositing finely divided electroscopic marking particles on the surface of the photoconductive insulating layer. The resulting visible image is then transferred from the electrophotographic substrate to a necessary member, such as, for example, an intermediate-transfer member or a print substrate, such as paper. This image developing process can be repeated as many times as necessary with reusable photoconductive insulating layers.
In image-forming apparatus such as copiers, printers, and facsimiles, electrophotographic systems in which charging, exposure, development, transfer, etc., are carried out using electrophotographic photoreceptors have been widely employed. In such image-forming apparatus, there are ever-increasing demands for speeding up of image-formation processes, improvement in image quality, miniaturization and prolonged life of the apparatus, reduction in production cost and running cost, etc. Further, with recent advances in computers and communication technology, digital systems and color-image output systems have been applied also to the image-forming apparatus.
Electrophotographic imaging members (such as photoreceptors) are known. Electrophotographic imaging members are commonly used in electrophotographic processes having either a flexible belt or a rigid drum configuration. These electrophotographic imaging members sometimes comprise a photoconductive layer including a single layer or composite layers. These electrophotographic imaging members take many different forms. For example, layered photoresponsive imaging members are known in the art. U.S. Pat. No. 4,265,990 to Stolka et al. describes a layered photoreceptor having separate photogenerating and charge-transport layers. The photogenerating layer disclosed in Stolka is capable of photogenerating holes and injecting the photogenerated holes into the charge-transport layer. Thus, in the photoreceptors of Stolka, the photogenerating material generates electrons and holes when subjected to light.
More advanced photoconductive photoreceptors containing highly specialized component layers are also known. For example, a multi-layered photoreceptor employed in electrophotographic imaging systems sometimes includes one or more of a substrate, an undercoating layer, an intermediate layer, an optional hole- or charge-blocking layer, a charge-generating layer (including a photogenerating material in a binder) over an undercoating layer and/or a blocking layer, and a charge-transport layer (including a charge-transport material in a binder). Additional layers such as one or more overcoat layer or layers are also sometimes included.
In view of such a background, improvement in electrophotographic properties and durability, miniaturization, reduction in cost, and the like, in electrophotographic photoreceptors have been studied, and electrophotographic photoreceptors using various materials have been proposed.
Production of a number of arylamine compounds, such as N,N,N′,N′-tetra(aryl)-1,1′-biphenyl-4,4′-diamine compounds that are useful as charge-transport compounds in electrostatographic imaging devices and processes, often involves processes that are costly and/or time-consuming.
Currently, such arylamine derivative hole-transporting molecules are prepared by a process that includes an Ullman reaction. The Ullman reaction involves the reaction of an aryliodide and an arylamine that includes the use of a copper catalyst that is either ligated or not, in the presence of a base. These reactions are typically carried out for long periods of time, at highly elevated temperatures, and with large amounts of base and catalyst. The starting materials can also be very expensive.
More recently, arylamine derivative hole transporting molecules have been prepared by a process that includes a palladium-ligated catalyst in the presence of a base. See, for example, commonly assigned U.S. patent application Ser. No. 10/992,690 filed Nov. 22, 2004. By use of this ligated palladium catalyzed process, an arylamine derivative can be economically manufactured in a shorter period of time that is isolatable in suitable purity to be used for example, for application in electrophotographic photoreceptors.
However, the above-mentioned process has its drawbacks. For example, the process typically uses palladium acetate ligated with tri-t-butylphosphine and sodium t-butoxide base as a reaction catalyst. While this scheme greatly reduces the reaction time, tri-t-butylphosphine is expensive and pyrophoric (spontaneously combusts in the presence of air).
Accordingly, improved processes providing safe, cost-effective, and efficient methods for arylamine production are desired.

Rapid cost effective method for the synthesis of TPD-type arylamines


The present invention relates to the improvement of the Bit Torrent protocol, which is one of the P2P protocols. A seeder flag is added to the active peer table. First a super seeder having the original is activated, and the super seeder is stopped when the total value of the seeder flags (number of activated seeders) reaches a certain level. The super seeders are activated only when the seeders having the original of a file are insufficient on the network, and are stopped when excessive. By this dynamic control, the number of activated processes of the super seeders can be decreased.

Prior Art (1)
A video file data distribution service using the Internet is being provided. FIG. 1 shows a diagram depicting this system, where data is directly distributed from a plurality of distribution servers 100 to client PCs (personal computers) 101 via the Internet 102.
The general protocols for distributing data in the system in FIG. 1 are as follows.    (1) http protocol (protocol used for a www server)    (2) ftp protocol (protocol used for a file server)    (3) rtsp protocol (real-time streaming protocol, protocol used for streaming formats)
The size of a video file is very large. If the file is a giga byte size, the load of the distribution server and the band consumption of the network lines are so large that it requires an enormous equipment investment and running cost if the data is distributed to many users simultaneously using a prior art.
In the above prior art (protocol), a server and a client PC (personal computer: viewer, user) are directly connected, and occupy the resources of the server and the line, so a cost in proportion to the number of users is required.
Prior Art (2)
One method to solve the above problem is a kind of P2P protocol (Peer-To-Peer, method for clients to communicate with each other without passing through a server) called the "Bit Torrent Protocol". As FIG. 2 shows, in this method files are transferred relaying packets from the server having the original file called a "super seeder" (also called the origin server) 110 as a start. Each server, which is called the leecher 111, distributes a portion, received as a piece seeder from the received portion, to other peers. A client which received at least a part of the file plays a role to distribute this portion, and is called the piece seeder. A peer which only receives is called a leecher hill 112. The leecher hill 112 responds to the client PC 101 in FIG. 1, and the piece seeder (leecher) 111 is the client PC 101 in FIG. 1, but also corresponds to the distribution server 100. The piece seeder (leecher) 111 transmits for the number of times of the reception, then the piece reaches to the last client. (Hereafter similar methods are collectively called the "Bit Torrent Method". "Packet relay distribution" is hereafter called the "grid distribution".)
The URL related to the Bit Torrent Method has the extension ".torrent". If this .torrent file is read by Bit Torrent-supported file sharing software, file sharing (download/upload of a file) starts. Even during the download of a file, the portion this client has downloaded thus far is uploaded when requested.
In theory a file reaches all the clients 111 and 112 if the seeder server 110 distributes the file once, regardless the number of clients, so the load on the seeder server 110 for one file is roughly constant regardless the number of clients. (In reality the distribution efficiency of an entire network is improved by executing not just once, but a plurality of times of distribution to a plurality of peers.)
FIG. 3 shows a diagram depicting a Bit Torrent system. To actually implement the Bit Torrent Method, a central control server called a tracker 120 exists to register and manage addresses of the peers (client PCs) P which participate in the grid distribution. The tracker server 120 receives a network participation request from each peer P, and creates a list of addresses (IP address and port) of the peers P which sent that request for each identifier (file ID) which uniquely specifies the file desired by a peer. This list is called the active peer table 120a (FIG. 4).
To participate in the network 121 in FIG. 3, the peer P first inquires the tracker server 120 to know the connection destination client of the grid distribution, and acquires the address of the connection destination peer P. At this time the address of the inquiry source peer P (IP address and port) and the identifier (file ID) which uniquely specifies the file desired by this peer P are registered in the active peer table 120a. The peer P which acquired the address of the connection destination by the response from the trackers server 120 connects with the corresponding peer P, and hereafter a packet relay type communication (grid distribution) is performed between the peers, as shown in FIG. 2. In FIG. 3, the bold line indicates the data communication and the fine line indicates the communication with the tracker server 120 for registration to the active peer table 120a.
The peer P is a client PC but can also be a seeder (seeder or piece seeder) as well. In other words, when a specific file is downloaded 100% (when file A or file B is downloaded 100% if one content file consists of file A and B), the client PC becomes a seeder, and is managed by the active peer table 120a as such. In the network 121 in FIG. 3, each node is indicated as "peer P" since whether the node is a seeder or not depends on the node. Each peer P of the network 121 is a seeder or a simple client (leecher) for a specific file. Status differs depending on the file and is not fixed, and a peer P that is a seeder for a specific file can be known by referring to the active peer table 120a.

Download method for file by bit torrent protocol


A hydrocephalus shunt having an anti-inflammatory coating applied to at least the outside surface of the ventricular catheter. Such coatings are also applicable to other medical devices or implants.

It is well known that infections occur in about 1% to about 5% of all primary arthroplasties, and that "the economic impact, the morbidity, and the emotional trauma of prosthetic joint infection is immense and devastating to the patient and society". Trampuz et al., Clin. Orthop., (414), 2003 pp. 69–88. The costs associated with revision surgeries and prolonged hospital stays due to deep wound infection are significant.
Postoperative wound infection (deep and superficial) in spinal implant cases for scoliosis and cerebral palsy patients has a particularly high frequency. The majority of deep wound infections in spinal cases are treated by irrigation and debridement while leaving the wound open, allowing it to heal. However, removal of the hardware associated with deep wound infections in these cases is often necessary.
It is believed that a majority of these infections occur via transmission from microbes upon the surgical gloves, the patient's skin, implants or instruments. Unlike routine systemic infections, infections associated with implants ("periprosthetic infections") are particularly troublesome.
First, it has been reported that certain biomaterials cause an abnormal and inferior immune response. In short, a portion of the immune response is provided by the release of superoxide ions, such as hydroxyl radicals, that are lethal to microbes. However, when a periprosthetic infection occurs, it has been reported that biomaterials such as cobalt chrome alloys cause abnormal neutrophil activity, resulting in an inferior non-productive immune response. Shanbhag, J. Biomed. Mar. Res., Vol. 26, 185–95, 1992.
Second, it appears that the presence of the implant surface helps the microbes survive both the immune response and antibiotic treatment. In particular, microbes of concern attach to the implant surface and form a polymer-like glaze (or "biofilm") between themselves and the local environment. This biofilm acts as an effective barrier to both neutrophils and antibiotics.
Although the periprosthetic infection itself is a primary concern for the patient, it is also known that the immune response triggered by the body to fight the infection also results in bone loss. In particular, the increased phagocyte concentration also increases the local concentration of tumor necrosis factor (TNF-α). The TNF-α concentration in turn upregulates the local level of osteoclasts. These increased osteoclast concentration uncouples the normal balance in bone metabolism, thereby leading to localized bone loss. This localized bone loss may result in the loosening of the implant, thereby necessitating its removal.
Prior art attempts at infection control have considered precoating spinal rods an intramedullary rods with an anti-infective coating. However, when the coatings at interconnection locations wear away, the space produced thereby leads to loose connections between the rod and the component to which it is connected.
In addition, prior art anti-infective coatings are typically cytotoxic to the microbes. This type of approach leads to building up resistance in the surviving microbes.
U.S. Pat. No. 6,503,507 ("Allen") discloses the use of a light-activated composition that produces singlet oxygen. Allen discloses that the singlet oxygen produced therefrom is effective in killing bacteria.
U.S. Pat. No. 6,527,759 ("Tachibana") discloses the use of light activated drugs that produce singlet oxygen.
Implant Sciences Corp. has promoted a surface treatment for percutaneous medical devices that prevents the growth of bacteria be employed the germ-fighting properties of silver coatings. U.S. Pat. No. 6,592,888 ("Jensen") discloses the use of metallic compounds in wound dressings to produce anti-microbial effects. U.S. Pat. No. 6,605,751 ("Gibbins") discloses the use of silver containing anti-microbial hydrophilic compositions. U.S. Patent Application 2003/0204229A1 ("Stokes") discloses the use of a polymeric casing containing cations as biologically active agents to be used on medical implants and devices.
Ohko, J. Biomed. Mat. Res. (Appl Biomat) 58: 97–101, 2001 reports coating titania upon silicone catheters and medical tubes, and illuminating those tubes with UV light. Ohko further reported the bactericidal effect of the subsequent photocatalysis on E. coli cells. However, Ohko states that TiO2 is toxic under illumination, and that because the part of the TiO2 coating buried in the patient's body can not be illuminated, the coating should not be harmful to the body. Therefore, it appears that Ohko discourages the in vivo irradiation of titania.
U.S. Published Patent Application 2003/0125679 ("Kubota") discloses a medical tube comprising an elastomer and a photocatalyst layer, wherein the tube is purported to have excellent antibacterial activity.
Hydrocephalus is a condition afflicting patients who are unable to regulate cerebrospinal fluid flow through their body's own natural pathways. Produced by the ventricular system, cerebrospinal fluid (CSF) is normally absorbed by the body's venous system. In a patient suffering from hydrocephalus, the cerebrospinal fluid is not absorbed in this manner, but instead accumulates in the ventricles of the patient's brain. If left untreated, the increasing volume of fluid elevates the patient's intracranial pressure and can lead to serious medical conditions such as subdural hematoma, compression of the brain tissue, dementia, impaired gait, and impaired blood flow.
The treatment of hydrocephalus has conventionally involved draining the excess fluid away from the ventricles and rerouting the cerebrospinal fluid to another area of the patient's body, such as the abdomen or vascular system. A drainage system, commonly referred to as a shunt, is often used to carry out the transfer of fluid. In order to install the shunt, typically a scalp incision is made and a small hole is drilled in the skull. A proximal, or ventricular, catheter is installed in the ventricular cavity of the patient's brain, while a distal, or drainage, catheter is installed in that portion of the patient's body where the excess fluid is to be reintroduced. To regulate the flow of cerebrospinal fluid and maintain the proper pressure in the ventricles, a pump or one-way control valve can be placed between the proximal and distal catheters. Such valves can comprise a ball-in-cone mechanism as illustrated and described in U.S. Pat. Nos. 3,886,948, 4,332,255, 4,387,715, 4,551,128, 4,595,390, 4,615,691, 4,772,257, and 5,928,182, all of which are hereby incorporated by reference. When properly functioning, these shunt systems provide an effective manner of regulating CSF in hydrocephalus patients.
After implantation and use over extended periods of time, these shunt systems tend to malfunction due to shunt occlusion. Frequently, the blockage occurs within the ventricular catheter. The obstruction can result from a number of problems, such as clotting, bloody CSF, excess protein content in the CSF, inflammatory or ependymal cells, brain debris, infection, or by choroid plexus or brain parenchyma in-growth through the openings of the ventricular catheter. Another potential cause of ventricular catheter occlusion is a condition known as slit ventricle syndrome in which the ventricular cavity collapses, thus blocking the openings of the ventricular catheter. If left untreated, the occlusion of the ventricular catheter can slow down and even prevent the ability of the shunt valve to refill, thereby rendering the shunt system ineffective.
In the past, the remedy for a clogged proximal catheter was to surgically remove and replace the catheter, which involved a risk of damage to the brain tissue or hemorrhage. The current trend is to rehabilitate the catheter in place through less invasive means. This can be accomplished in a procedure generally known as shunt or ventricular catheter revision which involves reaming the clogged catheter in its implanted state until the blockage is removed to thereby reestablish CSF flow through the ventricular catheter. Many shunt valves, such as the ones described in U.S. Pat. Nos. 4,816,016 and 5,176,627, are provided with a domed silicone reservoir that enables access to the attached ventricular catheter so that the system can be flushed out for this very reason. The self-sealing silicone dome can be pierced with a small needle to gain entry to the attached catheter, without affecting the ability of the dome to re-seal after the needle has been withdrawn. In some domed valves with right angle access, i.e., where the ventricular catheter extends at a 90 degree angle to the drainage catheter, a surgeon can gain entry to the clogged ventricular catheter percutaneously by inserting a rigid endoscopic instrument such as an endoscopic cutting tool or endoscopic electrode through the dome of the valve and straight down to the attached catheter. Thereafter, the obstruction can be cleared by cutting, cauterizing, or coagulating using the endoscopic instrument.
In addition, it is well known that infection is a well known complication associated with hydrocephalus shunts. It is well known that infections occur in about 5% to about 10% of all hydrocephalus shunt implantations. It is believed that a majority of these infections occur via transmission from microbes upon the surgical gloves, the patient's skin, implants or instruments. Unlike routine systemic infections, infections associated with implants ("periprosthetic infections") are particularly troublesome.
Therefore, it is an object of the present invention to provide an orthopedic implant and a hydrocephalus shunt adapted to prevent and/or treat occlusions and infections.


In a method and an apparatus for curtain coating of a moved substrate like a paper web substrate is moved below a liquid supply means providing a single or multilayer liquid coating in the form of a free-falling curtain impinging the substrate at a dynamic wetting line and a blade or air shield located upstream of the dynamic wetting line with respect to the moving direction of the substrate. The dynamic wetting line of the coating curtain on the substrate or web is oriented generally perpendicular to the moving direction of the substrate or web, providing substantially the same air pressure over an essential part of the coating curtain on its front and back side with respect to the moving direction of the substrate and providing a first supply air flow upstream to the wetting line. The supply air flows over a substantial length along the free-falling curtain and evacuates air from a location upstream of the supply air flow so that the air near the dynamic wetting line is moved against the moving direction of the substrate web and the boundary air layer entrained to the substrate. A second supply air is provided in proximity to the wetting line.

Mainly in the field of manufacture of photographic papers or coated films, curtain coating methods and apparatus are widely known and used. Typically a continuous web or sheets are continuously moved below a coating hopper. One or more liquid compositions are provided from a hopper arrangement in the form of a liquid curtain.
For the manufacture of photographic papers, liquid compositions are used of relatively low viscosity, generally less than about 150 cP (centipoise), most in the range from about 5 to about 100 cP.
The manufacture of photographic papers is a tremendously difficult art requiring extremely accurate control. The practical use of curtain coating provides a number of difficulties coming with a need for an extremely uniform coating on the one hand and a need for coating of substrates in form of a continuous web at high speeds on the other hand.
A number of problems associated with curtain coating have been addressed in the prior art and many proposals have been made to overcome such problems.
Besides obtaining a free-falling curtain having uniform curtain characteristics over its width perpendicular to the moving direction of the substrate, one of the most often addressed problems for coating at speeds higher than approximately 150 m/min is the displacement or deformation of the curtain by the air which is carried along the uncoated substrate due to friction. That air is carried along with the moving substrate to the coating point which designates the location where the coating liquid first contacts the substrate. In the curtain coating process this location has the form of a line across the substrate and is referred to as the dynamic wetting line. The area near the substrate where the air is in motion due to friction is called the boundary layer.
In the prior art a number of problems are described with respect to the air boundary layer.
One of these problems described for instance in U.S. Pat. No. 6,162,502 A is that air is entrained between the substrate and the liquid film and no coherent coating will be obtained at increased coating speeds.
Even if the air is not entrained between the substrate and the liquid film, the air strikes the curtain in the direction of motion of the substrate with considerable force, especially in the case of high-coating speeds. This leads to disturbances mainly in the area of the dynamic wetting line which cause diffused irregularities in the coated film, as described e.g. in U.S. Pat. No. 6,162,502 A and EP 0 489 978 B1.
Two main effects have been observed in the past in view of the boundary layer hitting a curtain. One is that the air layer hits the contact line between the curtain and the web. As the air needs to reverse its flow direction, the displacement of the wetting line is not uniform over the length over the curtain, and the curtain assumes a wavelike or undulating deformation across the web substrate. As a consequence of the curtain deformation the coated layer gets areas of varying thickness of the coating, which means that the coated layer gets band like thickness deviations along the moving direction of the web.
Another effect is that the curtain is blown up in the direction of the motion of the substrate like a balloon. This results not only in deformation of the wetting line but also results in an irregular coating behavior of the curtain transversely to the coating direction and the momentum of the air or the pressure difference over the curtain may temporarily slit the curtain, thus inducing streaks in the coating.
In a curtain coater arrangement involving an air shield located between a roller for supporting and forwarding the substrate a number of methods are known for mitigating the detrimental effect of boundary layer air. One approach is reported in U.S. Pat. No. 3,508,947 to Hughes where the minimization of entrained air on the moving web is proposed by use of an air shield that has been provided with a vacuum manifold which is positioned adjacent to the web to be coated and connected to a vacuum pump to withdraw air therefrom. In this manner Hughes proposes that the multi-layer, free-falling vertical curtain of coating material is shielded from ambient air currents and the air entrained by the moving web is drawn off before the curtain impinges on the moving web at the wetting line.
U.S. Pat. No. 5,976,630 reports a more recent curtain coating practice employing the air shield mainly for the purpose of drawing off air entrained by the moving web as opposed to shielding the free-falling curtain from ambient air currents. This is because curtain coating operations typically include an enclosure to shield the free-falling liquid curtain from ambient air currents. The enclosure is continuously supplied with a laminar low velocity air flow from the top, while at the same time air is exhausted from both the front and rear of the enclosure. It is known that air shield systems employing a single manifold and a single vacuum source have been operated to exhaust higher air volumes in an attempt to remove additional air from behind the free-falling curtain as well as air entrained on the web.
U.S. Pat. No. 5,224,996 to Ghys et al. is reported to teach an alternative design for a curved air shield arrangement close to a backing roller which supports the moving web at the point of impingement. The design taught for the air shield provides for increased resistance to air flow in the gap between the air shield and the backing roller at the end and side regions thereof as compared to air flow resistance at an intermediate region of the shield. The vacuum device communicates with the gap in the intermediate region to reduce air pressure therein. In such manner, there is an improved removal of boundary layer air at the surface of the moving web prior to the impingement point or wetting line which apparently allows a better coating quality at increased speed of the moving web.
EP 0 489 978 B1 further describes additional arrangements to increase the air resistance by further means like protruding parts, strips or even one or more laminae connected to the air shield and directed towards the web. The laminae are taught to extend over the total width of the air shield or a group of smaller randomly placed laminae. The aim which should be reached by such an arrangement is described to obtain a reduced pressure with a low flow rate of evacuated air. Higher flow rates are reported not to be desirable since they can cause non-uniformities inside the air shield. Such non-uniformities are reported to cause band-like disturbances in the coated material.
EP 0 489 978 B1, the disclosure of which is hereby incorporated by reference, further reports that the pressure difference between the ambient air and the inside of the air shield has to be high enough to evacuate the boundary layer of air adhering to the web, but needs to be limited to avoid an air flow in a direction from the coating curtain towards the air shield, that is against the moving direction of the web. It is reported that an air flow from the coating curtain towards the air shield may cause the entire liquid curtain or at least a part of it to become sucked up into the air shield, therefore destroying the coating procedure, which is to be avoided under any circumstances.
Further, it is described to arrange the outlet end of the air shield at a distance between 5 and 30 mm upstream of the wetting line, because smaller distances involve the risk for a swinging curtain to touch and to soil the air shield, thereby interrupting the coating process, whereas larger distances strongly reduce the effect of the air removal and allow rebuilding of a new boundary layer of entrained air.
U.S. Pat. No. 5,976,630 to Korokeyi et al. proposes use two different intake slots in combination with an air shield which slots are connected to one common or two separate vacuum pumps, wherein one air intake slot is dedicated to removing the entrained boundary air layer of the moving substrate and one is dedicated to the removal of the entrained boundary air layer of the free-falling curtain. Further it is proposed to provide fresh, filtered, optionally heated, laminar, low velocity air flow having a speed of about 10 to about 20 ft/mm (about 5 to about 10 cm/s) which is supplied to the enclosure surrounding the free-falling curtain through an upper perforated wall thereof It is further mentioned that the free-falling curtain is to be supplied with fresh air as spent air as withdrawn from the enclosure surrounding the apparatus through exhaust ports in the enclosure. The exhaust ports are described essentially to remove the supplied air to minimize pressure differential across the free-falling curtain. The teaching of U.S. Pat. No. 5,976,630 is intended to reduce or avoid circulation or vortex pattern of air currents along the curtain which is known to cause disturbances in the curtain which in turn can lead to streaks in the coated product.
U.S. Pat. No. 6,146,690 to Kustermann describes an arrangement for curtain coating for instance of a paper web which should prevent forming of air bubbles by parts of a boundary air layer entrapped between the substrate and the coating applied in an amount making the coated product economically unusable at coating conditions where the web has a width up to 4 m and coating speeds at up to 1000 m/min. To achieve this goal, it is proposed to locate a dynamic air pressure sensor in close proximity to the wetting line where a coating medium contacts the material web surface, and where an increased dynamic pressure relative to the normal air pressure should be observable caused by the boundary air layer entrained to the substrate web. The dynamic pressure signal is compared to a predetermined dynamic pressure value and a suction device to remove air entrained to the substrate web and/or the coating curtain is controlled to maintain a predetermined dynamic pressure value near the wetting line on the substrate.
In a further embodiment of the invention described it is proposed to provide a scraper bar for removal of the air entrained with a moving surface of the substrate located upstream from the wetting line to reduce the mechanical power needed for the suction device, and, further, it is suggested to engage an additional suction device producing a partial vacuum on the side of the substrate web facing away from the coating curtain pulling the substrate web against a support element like a backing roll.
U.S. Pat. No. 6,162,502 to Schweizer et al. proposes to engage a suction channel and an air supply channel within an air shield, both engaging a porous layer towards the substrate web. The air supply channel is arranged between the layer suction channel and the dynamic wetting line and the air supply is proposed to be adjusted in function of the extracted air in such a manner that a parabolic velocity profile develops providing an air velocity equal to zero between the air shield and the substrate with the aim to prevent any air flow in front of the wetting line where the coating curtain strikes the substrate. It is pointed out to be important that the air volume to be extracted is not drained from the space between the air shield and the curtain which needs to be avoided according to the teaching of this patent to prevent from any disturbing air flows in front of the curtain.
U.S. Pat. No. 5,624,715 to Gueggi et al. proposes to extract any air entrained with a moving substrate via a slot at the edge of a blade oriented towards the curtain so that the size of the remaining boundary layer striking the curtain is minimized. Further, an air supply opening is proposed at the underside of a lip of the curtain hopper to provide air to this point at a low speed and downwardly deflected, which low speed air flow is also evacuated by the slot of the blade arranged at the edge of the blade facing towards the curtain. By these measures the formation of rotating air turbulences between the blade and the curtain should be avoided which otherwise may divide into individual unstable cells causing the curtain becoming disturbed and unsteady and, consequently, results in a reduced coating quality.
WO 01/16427 A1 assigned to Valmet Corp. proposes a curtain coater with a conventional doctor arrangement upstream in the travel direction of a web substrate in front of an impingement point of the coating mix curtain on the surface of the web. According to the teaching of this document, besides provision of an usual evacuating means within the doctoring means, it is proposed to increase the momentum of the coating mix curtain by making the height of the falling curtain larger and thereby increasing falling velocity so that the coated liquid becomes more energetic to penetrate through the boundary air layer travelling on the web surface. More particularly it is proposed to provide a gas-injection nozzle downstream from the curtain supplying a significant stream of gas, including air or steam, towards the coating curtain near the wetting line so that the combined momentum of the coating mix curtain and the gas jet becomes sufficiently energetic to force the coating mix to penetrate through the boundary air layer travelling on the web surface and thus, the curtain can unobstructedly adhere to the surface of the web.
Although many approaches have been made in the prior art to overcome the drawbacks and problems coming with the use of a curtain coating process, in particular at high coating speeds, there are still remaining drawbacks effecting the quality and cost effectiveness of curtain coating methods, in particular with respect to curtain coating of paper substrates.

Method and apparatus for curtain coating


A method of judging a sector synchronous signal for a disk reproducing apparatus, includes a first step for decoding and storing a synchronous signal, a second step for comparing the decoded synchronous signal with a reference sector synchronous signal, a third step for assuming the detected synchronous signal to be a sector synchronous signal when the decoded synchronous signal and the reference sector synchronous signal are identical based on a result of the second step, a fourth step for judging whether the synchronous signal stored before the decoded synchronous signal indicates a desired state, and a fifth step for finally judging that the assumed sector synchronous signal is a sector synchronous signal based on a result of the fourth step.

1. Field of the Invention
The present invention relates to a sector synchronous signal judgement and generation method for a disk reproducing apparatus and more to an improved sector synchronous signal judgement and generation method for a disk reproducing apparatus which is capable of preventing an erroneous recognition of a sector synchronous signal due to a noise or bit errors and generating a sector synchronous signal which was missed.
2. Description of the Conventional Art
Generally, a compact disk (CD) is widely used for a disk reproducing system as a reproducing medium. The CD uses only a frame synchronous signal which can be expressed in various forms (for example, 10000000000100000000001).
However, a sector synchronous signal for separating a sector exists in a digital video disk (DVD) system in addition to the frame synchronous signal. In the DVD system, the sector synchronous signal cannot be expressed as the frame synchronous signal as in the CD because the sector synchronous signal has various restrictions in a coding method, a signal offset of a low frequency band width, etc. Therefore, one synchronous signal is arranged in a head portion of each sector for separating the sectors after various kinds of synchronous signals are generated.
FIG. 1 is a view illustrating a synchronous signal used in a conventional digital video disk.
As shown therein, on the assumption that there is a "a" number of synchronous signals, each synchronous signal (SY0, . . . , SYa) including an the m-number of binary bits.
In addition, each synchronous signal (SY0, . . . , SYa) includes a bit X and a frame synchronous signal "frame sync". The bit X is formed of 0 and 1, and the frame synchronous signal is of a fixed type.
FIG. 2 is a view illustrating a conventional sector structure.
As shown therein, one synchronous signal SYxl among various synchronous signals is used as a synchronous signal of a first frame of the sector, and the other synchronous signals (SYx2, . . . , SYxn) are used as the synchronous signal of the remaining frames. Namely, when the synchronous signal SYx1 is detected, the thusly detected synchronous signal SYx1 becomes a sector synchronous signal.
However, when detecting the sector synchronous signal by using the above-described structure, the sector synchronous signal SYx1 may be lost due to noise or the like at the moment when the sector synchronous signal SYx1 is detected and is mistakenly judged as another signal, thereby causing a malfunction in the system and degrading the quality of a picture to be displayed.
Furthermore, since the CD judges the sector synchronous signal by using only the frame synchronous signal, it is impossible to properly match with the synchronous signal having various types as in the DVD, thereby increasing the possibility of the errors.

Method of forcibly judging a sector synchronous signal for a disk reproducing apparatus


A suite of tests and parameter monitoring methods for at least five major subsystems that are found in most automated image processing systems, as well as calibration routines for three major system functions. The five areas of subsystem verification include processing quality, illumination quality, image collection quality, autofocus quality, and position quality. An automated biological specimen analysis system uses self measures of system parameters to provide a system status. The system status is reported to the user.

Automated cytology instruments are required to perform at a high degree of integrity. Errors caused by such biological specimen analysis systems may have potentially catastrophic effects. Therefore, it is highly desirable for automated biological specimen instruments to monitor themselves at regularly defined intervals. Monitoring may comprise a series of automated tests of each critical subsystem in the instrument.
Generally systems that perform automated scanning have five critical subsystems including illumination, image collection, autofocus, positioning and image processing systems.
In order to achieve a high degree of accuracy and repeatability, such automated biological specimen analysis systems tend to be complex, because they may contain thousands of components. Such complexity demands measuring a large number of parameters to accurately characterize the functionality of such a system. Typically, for instruments manufactured for applications like automated semiconductor wafer and photomask inspection, testing is done at the time of manufacture with stand alone oscilloscopes, spectrum analyzers displacement transducers and the like. Once the instruments pass such tests, they are shipped to customer sites. Typically, problems with these instruments are usually corrected only if they have a major impact on the efficacy of the device. Minor fluctuations in the efficacy of such instruments go unnoticed. It is common practice to run a suite of diagnostic tests only in accordance with regularly scheduled preventative maintenance programs. This may be typically scheduled several times a year. Unfortunately, the instruments are usually taken off line to run such tests and, as a result, productivity suffers. Until the scheduled tests are done, the untested instruments may produce faulty results for months before any problems are caught and rectified.
In addition, standard practice does not facilitate rapid advancement of image processing technologies. Many image processing applications are highly statistical. Therefore large amounts of data must be collected before reasonable conclusions can be drawn. This is particularly true in image processing applications concerning biological specimens where measured features characterizing objects in biological specimens such as, for example, area, perimeter, frequency content, and optical density, among others, vary along a continuum. The standard deviation of any particular feature may be quite large. Further, to obtain accurate, repeatable, and reliable diagnosis of a biological specimen, hundreds of features may be measured for each object in an image. This is further compounded by the fact that thousands of specimens must be evaluated to determine the efficacy of a device. Therefore, image and object feature calculations are taken over the time frame of months. The problem in advancement of image processing technology partially lies in the fact that it is very difficult to know exactly how various system parameters, such as illumination uniformity or image collection frequency response, affect the outcome of various feature calculations. Since standard practice only allows for the measurement of system parameters over long time periods, on the order of months, and requires taking systems scheduled for maintenance out of productivity, to use stand alone equipment, it is nearly impossible to determine system performance at any specific time between maintenance periods. Such uncertainty makes relating system parameters to feature calculation results nearly impossible.
The present invention, for the first time, serves to substantially reduce such reliability problems by providing an automated, on line test to quickly identify any unacceptable deviations in system performance. The apparatus and method of the invention allows formulation of more reliable relationships between system parameters and feature calculations.
The present invention provides an automated method to perform such tests. In accordance with the novel aspects of the invention, testing is done using a test slide containing calibrated clear areas and image primitives that stimulate components of the automated biological specimen analysis system to produce a quantifiable effect. The quantifiable effects are compared to system specifications to ensure that the automated biological specimen system is operating within its engineered limits. If the automated biological specimen analysis system fails to meet these limits, appropriate action is taken. Failing a test may result, for example, in invalidation of all slide results produced since the last acceptable system integrity testing sequence.

Biological specimen analysis system processing integrity checking apparatus


A substrate on which a silicon device is mounted in accordance with an embodiment of the present invention includes a plurality of protrusions extending upward from a top surface of the substrate and a solder layer formed on the top of the substrate such that the plurality of protrusions extends through the solder layer and a top portion of each protrusion of the plurality of protrusions is stamped down to be level with a top surface of the solder layer such that the silicon device is supported on the plurality of protrusions when placed on the substrate. The protrusions are preferably gouged up from the surface of the substrate with a needle like tool. A stamper tool is used to stamp the protrusions down to their desired height such that they are properly positioned to support the silicon device. The solder layer may be a solder pre-form or may be a layer of solder paste. The solder layer is heated to form liquid solder to bond the substrate and the silicon device, however, the protrusions support the silicon device to prevent movement thereof when the solder is in liquid form.

Advances in semiconductor technology have driven the performance limits of silicon beyond the capabilities of present packages. In particular, the power and current carrying capability of MOSFETS and IGBT's are often limited by insufficient package performance. The thermal and electrical resistance of the package results in power losses and corresponding heating of silicon beyond the limits thereof. In addition, the inductance of the package also results in certain limits for use with high switching currents. In particular, parasitic package inductance may result in inductive over-voltage that can destroy the silicon device (Si-device). This is a particular problem in conventional packaging that utilizes bond wires for the electrical connection of the top metal of the Si-device to a lead frame or other external metal terminals.
Newer packaging technologies attempt to minimize inductance and provide improved thermal connectivity to a heatsink by bond wireless connection techniques. One example of such packaging is provided in assignee International Rectifier Corporation's Direct DirectFET® line of products which are further described in U.S. Pat. No. 6,624,522, the entire contents of which are hereby incorporated by reference herein. Another example of such alternative packaging technology utilizing a horseshoe-shaped direct bonded copper substrate (DBC) can is provided in assignee's Provisional Patent Application Ser. No. 60/761,722, filed Jan. 24, 2006, entitled STRESS-REDUCED BOND-WIRELESS PACKAGE FOR HIGH POWER DENSITY DEVICES (IR-3177 Prov) from which Assignee's presently co-pending application Ser. No. 11,641,270 entitled PACKAGE FOR HIGH POWER DENSITY DEVICES filed Dec. 18, 2006 claims priority. The entire contents of each of these applications is hereby incorporated herein by reference. In these references, a Si-device, or die, is mounted in a can-shaped housing and the top side of the power device (source/emitter and gate contact) is soldered to a metal pad in order to gain higher current carrying ability, reduced inductance and better thermal performance. In particular, for power switches, providing a large metal contact on both sides of the Si-die is beneficial to optimize electric and thermal performance.
The introduction of such bond wireless die attachment designs, however, makes the solder joint more important. In particular, the solder joint and the potential failure mechanism of this contact layer has a major influence on the quality and reliability of products in which it is used. The solder joint becomes particularly important when the solder joint forms both the electrical and mechanical contact layer on the top and bottom of the Si-device.
Typically, the top side of the die is contacted by wire bonds to a substrate or leadframe. In the case of bond wireless technology, solder bumps are provided on the die on a wafer level. The bumps are relatively small for the gate pad of a power switch or for IC contact pads (e.g. ball grid arrays) and are relatively large when used to establish high current connections for source pads of MOSFETS or IGBTs, for example.
Further, generally, the back side of the Si-device is usually soldered to a substrate such as a metal leadframe, DBC, printed circuit board (PCB) etc. This solder area is relatively large and typically corresponds to die size. For this back side attachment, it is common to use a solder paste which is a mixture of a solder alloy (such as PbSn or lead free SnAgCu) and a flux. The flux is used to clean the contact surfaces and optimize the wetting of the solder, especially on oxidized surfaces such as copper. Typically, the solder paste is dispensed or stencil printed on the substrate (leadframe, DBC, PCB, etc) and then the die is placed in the solder paste nest. The solder paste is then melted in a solder oven (or reflow oven) to form the intermetallic contact between the Si-metallization and the substrate metal.
Using this technology, it is common to adjust the solder thickness oven profile (temperature and time). However, this approach does not provide for very close control of solder thickness. For example, die movement during the liquid phase of the solder paste often results due to creeping or flow of the liquid solder. Such creep and/or flow cannot be well predicted. Further, different wetting of the solder paste to the substrate or leadframe may result in a thinner or thicker distribution of solder, and thus, variations in the thickness of the final solder layer.
One means for addressing these problems is the use of a pattern of solder-stop lacquer on the substrate or leadframe to prevent the solder from spreading too far or by otherwise limiting the metal pad area. However, such techniques are generally expensive and don't completely prevent die movement. For example, such techniques do not address problems that can arise when the die is tilted. Further, when such techniques are used, it is difficult to change the die, solder pattern or solder thickness without changing the tooling and other equipment used, which can be expensive and time consuming.
Shifts in the position of the die result in the die not being properly postioned relative to the circuit pattern and/or may result in the die being tilted in one direction or the other. Further, chemical reactions between the flux and the contact surfaces can result in bubbling of the solder when in the liquid phase. This is another source of unwanted movement of the die.
These problems may not reduce yield in certain applications. That is, the movement of the die may not be a problem in certain applications, however, precise positioning of the die may be critical in other applications. Even small movements of the die can be a problem for wire bond processes to fine-structure pads or when the Si-device is to be flip-chip soldered with narrow tolerances in bump position (height and location). It is particularly important that the die be level and well positioned after mounting in the metallic can used in the DirectFET® line of products.
One other problem with present solder paste technology is the residue of the flux that is typically stuck to the die or substrate after the solder process. This residue may be hard to remove, and if not removed, may cause problems with wire bonding or other electrical contact techniques. Also, any subsequent mold processing would require that the flux be removed. Thus, the removal of the flux is often necessary, and thus represents additional expense.
An alternative technique is the use of so-called solder pre-form in place of the solder paste. The solder pre-forms are typically pre-formed sections of solder foil with a defined thickness (typically 10 μm to over 100 μm) and dimensions that roughly correspond to the desired solder pad size. These pre-forms are typically used without flux. They are typically soldered via a formic gas vacuum soldering process in which formic gas (e.g. formic acid in gas phase) performs the role of the flux to clean the surfaces without leaving a residue. However, this technique still makes it difficult to control the thickness of the solder layer. While the thickness of the solder layer is set by the thickness of the solder pre-form, when the solder melts, this thickness changes. Further, the die also moves when the solder melts, which also results in variation of the solder thickness as noted above.
FIG. 1 is an illustration of an Si-device, of die, 100 that is mounted on a substrate, or leadframe, 102 via a solder layer 104 with varying thickness 104a, 104b. As illustrated, the conventional techniques result in variations in the position of the die 100 on the substrate 102 and the additional problems of the flux residue 106 noted above. For example, in FIG. 1, better wetting of the substrate 102 on one side of the die 100 has resulted in the solder spreading further in that direction. Thus, the thickness of the solder layer 104 on that side is smaller than that on the other side and the die 100 is tilted.
The problems described above and illustrated in FIG. 1 are common in all conventional Si-die attachment techniques. In some applications, these variations are not a particular problem. However, in applications where a single device needs to be soldered precisely in a metal housing, like a MOSFET in the DirectFET® line of products noted above or in the horseshoe-shaped can mentioned in the co-pending application entitled PACKAGE FOR HIGH POWER DENSITY DEVICES mentioned above, these variations are unacceptable.
In order to avoid some of these problems, an adhesive may be used to attach the Si-die, or device, to the metallic can. For example, adhesives may be used to attach the Si-device in the DirectFET® line of products since the adhesive glue can be better controlled. However, a solder connection would provide superior electrical and thermal characteristics and would provide for an increase in the current carrying ability. However, as described above, conventional solder bonding does not provide for precise enough control to allow for its use in the DirectFET® line of products. In particular, the DirectFET® line of products require that the gate bumps and source bumps be in a precise position and perfectly level with respect to the metallic can, which are problems with the soldering techniques described above.
One alternative means for mounting one device on another is proposed in U.S. Pat. No. 4,934,679 to Kaiser. In Kaiser, a positional fixation element, or elements, are provided on a first structural component to fix the position of a second structural component that is mounted on the first structural component. A mandrel-like tool is used to form the positional fixation elements(s). Specifically, the tool is pressed into the first component on an incline relative to a reference plane of the first element. In the process, material is displaced to form a groove and an accumulation of material with a shape corresponding to that of the position fixation element. The position fixation element(s) are suitable for positioning electrical circuits, for example, when glued or soldered onto a first component. While the positional fixation elements of Kaiser may be useful to position the second component, the mandrel tool used to make them may not always provide an equal accumulation of material, and thus, the positional fixation elements may not provide a stable support for the second component.
Thus, it would be beneficial to provide a substrate and method that allows for mounting a Si-device thereon using solder that avoids the problems described above.

Substrate and method for mounting silicon device


The present invention describes a method for forming interconnections in semiconductor device fabrication. A via (or trench) is formed on a semiconductor substrate. A metal layer is deposited over the semiconductor substrate using directional sputtering techniques. The metal layer is deposited such that the resulting metal layer has a large surface area and a high degree of curvature. The metal layer is then reflowed. During reflow, the high degree of curvature of the metal layer improves the migration of the metal layer. Thus the metal layer is distributed in a manner that rapidly and more evenly fills the via thereby forming a reliable interconnection.

1. Field of the Invention
The present invention relates to semiconductor processing, and more specifically to a method of reflowing copper to form interconnections in a semiconductor device.
2. Background Information
As the demand for cheaper, faster, lower power microprocessors increases, so must the device packing density of the integrated circuit. Very large scale integration (VLSI) techniques have continuously evolved to meet the increasing demand. All aspects of the integrated circuit must be scaled down to fully minimize the device dimensions of the integrated circuit. In addition to minimizing the device themselves, the dimensions of the electrical interconnections which integrate those devices must also be minimized.
Interconnections increasingly determine the limits in performance, reliability, and power consumption for semiconductor devices. As VLSI dimensions reach into the deep-submicron Ultra Large Scale Integration (ULSI) regime, interconnections for such devices require new materials and new processes for fabrication.
Currently, aluminum (Al) and aluminum alloys are the most commonly used conductive materials for electrical interconnections. Aluminum and its alloys have been fully characterized for use as electrical interconnections and technology has been developed to aid in the formation of aluminum interconnections. While aluminum has very attractive features for use as an electrical interconnection, such as low electrical resistivity and strong adhesion to silicon dioxide (SiO.sub.2), as the dimensions of semiconductor devices and their interconnections decrease, the deficiencies of aluminum and its alloys become limiting factors in achieving superior performance. For example, as electrical interconnections become deeper and narrower, it becomes harder to fabricate such interconnections using aluminum without the formation of voids. Void formation is described in detail below with respect to copper, however, it will be obvious to one with ordinary skill in the art that void formation in aluminum interconnections occurs in a similar manner to that of void formation in copper interconnections. Additionally, with decreasing dimensions, design rules become increasingly restricted by aluminum interconnection reliability concerns such as electromigration, stress-induced void formation, hillock suppression, and current density limitations.
For these reasons, the microelectronics industry has recently migrated towards the investigation of more robust, more conductive metals for use in interconnection technology such as Copper (Cu). Copper is approximately 40% lower in resistivity than aluminum and is much more resistant to reliability problems such as electromigration. One of the main reasons why the use of copper and its alloys for interconnection applications has not been more widespread is because a manufacturable dry-etch process has not yet been demonstrated that can pattern copper-based materials using standard photolithographic techniques. FIGS. 1a-1d illustrate a dry-etch process used to try to pattern copper and copper alloy interconnects.
In FIG. 1a, a metal layer 110 has been deposited above silicon dioxide (SiO.sub.2) layer 100. For this example, metal layer 110 may be made of copper or a copper alloy. A photoresist layer 120 has been deposited and patterned on top of metal layer 110. Processes for photoresist deposition and patterning are well known in the art and are therefore not described herein.
The structure of FIG. 1a is then subjected to a dry-etch process, for example, reactive-ion etch (RIE), in order to etch away the exposed portions of metal layer 110. The unexposed portions of metal layer 110 which remain after the etch is performed form interconnects 130. As illustrated in FIG. 1c the photoresist is then removed. Finally, oxide 140 is deposited between the interconnections 130, as is illustrated in FIG. 1d.
The problem with dry-etch processes for forming copper interconnects is that all the copper halides have low vapor pressures at room temperature. Etching at low vapor pressures equates to slower etch rates and longer processing times. High vapor pressures allow materials to etch faster, however copper halides, such as chloride and fluoride, only have high enough vapor pressures for etching at temperatures above 200.degree. C. which is too high for most photoresists. To implement the use of copper as a microelectronic interconnection material, it has therefore become necessary to develop alternate patterning techniques.
One technique is known as damascene. In damascene, a dielectric layer is deposited onto a substrate, patterned, and etched back such that the trenches, grooves, vias, or other recessed regions etched into the dielectric layer represent the desired metal interconnection pattern. A conductive material is then deposited over the entire surface of the device, filling in the recessed regions and blanketing the surface of the dielectric layer. Next, the conductive material is etched back to a degree such that the conductive material becomes electrically isolated within the recessed regions etched out of the dielectric layer.
One problem with the damascene process, however is that it is difficult to fill the trench or via with a conductive material without the formation of voids or tunnels which result in interconnections that would have significant reliability problems and degraded electrical performance. Such void formation would ultimately degrade semiconductor device yields thereby adding to the total manufacturing cost. FIGS. 2a-2e illustrate a damascene process.
FIG. 2a illustrates a semiconductor substrate 200 with a dielectric layer 240 deposited on its surface. Dielectric layer 240 is then etched using conventional etch techniques to create trenches 250, as illustrated in FIG. 2b. FIG. 2c illustrates the semiconductor substrate of FIG. 2b during the sputter deposition of a conductive or metal layer 230 on its surface. Note that gap 260 has formed in the metal layer 230.
As the conductive material is deposited onto the substrate in FIG. 2c, the conductive material may be deposited at a faster rate on the top surface and along the walls nearer the top surface than at the bottom of trench 250, thus forming gap 260 and overhangs 270. During deposition, overhangs 270 become larger making it increasingly more difficult to deposit and flow any more conductive material into gap 260. Eventually, as illustrated in FIG. 2d, overhangs 270 will touch and "pinch" the opening of trench 250 shut. Thus, the flow of the conductive material into gap 260 is stopped altogether and void 280 is formed. If the top surface of the substrate is etched back at this point, as illustrated in FIG. 2e, void 280 will remain inside trench 250 leading to the problems described below as well as limiting the current carrying capability of the electrical interconnection.
Voids can cause significant problems in a semiconductor manufacturing process and are considerable issues for sputtered and evaporated films. One problem with voids is that they can trap impurities which can harm the semiconductor device in subsequent process steps. Assuming metal layer 230 of FIG. 2d was etched back using some sort of chemical etching process, the etchant chemicals may become trapped within the void 280 and cause additional etching or corrosion of electrical interconnection 230 even after the etchant has been removed from the surface of the substrate. These trapped etchant chemicals may then contaminate the semiconductor device and could degrade reliability.
Trapped etchant chemicals may also continue to etch the electrical interconnection 230 resulting in the thinning of electrical interconnection 230 and cause the creation of a electrical open, thereby resulting in a failure. Interconnection thinning may also lead to other reliability problems such as electromigration and current-carrying limitations. Another problem is that trapped contaminants may expand if the semiconductor substrate is subjected to subsequent high temperature processing steps. Such expansion could cause significant damage to adjoining surface features of the semiconductor device. Additionally, trapped contaminants may escape during, for example, a subsequent process step thereby contaminating all other semiconductor devices within the process chamber.
It should be noted and it will be obvious to one with ordinary skill in the art, that the potential for forming voids is greatly increased by attempting to fill grooves of significantly varying widths together on a single substrate at the same interconnection level. This is because these deposition processes are typically optimized to fill a groove (or trench) of a particular width and depth. While such optimization techniques may be suitably employed to fill interconnections of one particular width on a semiconductor substrate, the problem is that grooves of other widths for which the process has not been optimized run a much higher risk of void formation. This makes interconnection technology dependent on individual device layout. Such dependence degrades the manufacturability of such processes.
Thus, what is needed is a method for reflowing conductive layers into vias (or trenches) that decreases the formation of voids, decreases fabrication time, and increases the reliability of the electrical interconnections of a semiconductor device.

Rapid reflow of conductive layers by directional sputtering for interconnections in integrated circuits


Viral vectors and methods of making such vectors are described that preferentially kill neoplastic but not normal cells, the preferred vector being an adenovirus that has the endogenous promoters in the E1A and/or E4 regions substituted with a tumor specific promoter which is preferably E2F responsive.

From the early part of this century, viruses have been used to treat cancer. The approach has been two-fold; first, to isolate or generate oncolytic viruses that selectively replicate in and kill neoplastic cells, while sparing normal cells. Investigators initially used wild type viruses, and this approach met with some, albeit, limited success. While oncolysis and slowing of tumor growth occurred with little or no damage to normal tissue, there was no significant alteration in the course of the disease. See, Smith et al., Cancer 9: 1211-1218 (1956), Cassel, W. A. et al., Cancer 18: 863-868 (1965), Webb, H. E. et al., Lancet 1: 1206-1209 (1966). See, also, Kenney, S and Pagano, J. J. Natl. Cancer Inst., vol. 86, no. 16, p. 1185 (1994).
More recently, and because of the reoccurrence of disease associated with the limited efficacy of the use of wild type viruses, investigators have resorted to using recombinant viruses that can be delivered at high doses, and that are replication competent in neoplastic but not normal cells. Such viruses are effective oncolytic agents in their own right, and further, can be engineered to carry and express a transgene that enhances the anti neoplastic activity of the virus. An example of this class of viruses is an adenovirus that is mutant in the E1B region of the viral genome. See, U.S. Pat. No. 5,677, 178, and Bischoff, J. R., D. H. Kirn, A. Williams, C. Heise, S. Horn, M. Muna, L. Ng, J. A. Nye, A. Sampson-Johannes, A. Fattacy, and F. McCormick. 1996, Science. 274:373-6.
It is important to distinguish the use of replication competent viruses, with or without a transgene for treating cancer, from the second approach that investigators have used, which is a non-replicating virus that expresses a transgene. Here the virus is used merely as a vehicle that delivers a transgene which, directly or indirectly, is responsible for killing neoplastic cells. This approach has been, and continues to be the dominant approach of using viruses to treat cancer. It has, however, met with limited success, and it appears to be less efficacious than replicating viruses. Nevertheless, foreign genes have been inserted into the E1 region (see McGrory, Virology 163: 614-17 (1988)), the E3 region (see Hanke, Virology 177: 437-44 (1990) and Bett, J. Virol. 67: 5911-21 (1993)) or into the E3 region of an E1 deleted vector.
As mentioned above, to avoid damage to normal tissues resulting from the use of high dose viral therapy it is preferred that the virus have a mutation that facilitates its replication, and hence oncolytic activity in tumor cells, but renders it essentially harmless to normal cells. This approach takes advantage of the observation that many of the cell growth regulatory mechanisms that control normal cell growth are inactivated or lost in neoplastic cells, and that these same growth control mechanisms are inactivated by viruses to facilitate viral replication. Thus, the deletion or inactivation of a viral gene that inactivates a particular normal cell growth control mechanism will prevent the virus from replicating in normal cells, but such viruses will replicate in and kill neoplastic cells that lack the particular growth control mechanism.
For example, normal dividing cells transiently lack the growth control mechanism, retinoblastoma tumor suppressor, that is lacking in and associated with unrestricted growth in certain neoplastic cells. The loss of retinoblastoma tumor suppressor gene (RB) gene function has been associated with the etiology of various types of tumors. The product of this tumor suppressor gene, a 105 kilodalton polypeptide called pRB or p105, is a cell-cycle regulatory protein. The pRB polypeptide inhibits cell proliferation by arresting cells at the G1 phase of the cell cycle. The pRB protein is a major target of several DNA virus oncoproteins, including adenovirus E1a, SV40 large T Ag, and papillomavirus E7. These viral proteins bind and inactivate pRB, and the function of inactivating pRB is important in facilitating viral replication. The pRB protein interacts with the E2F transcription factor, which is involved in the expression of the adenovirus E2 gene and several cellular genes, and inhibits the activity of this transcription factor (Bagchi et al. (1991) Cell 65: 1063; Bandara et al. (1991) Nature 351: 494; Chellappan et al. (1992) Proc. Natl. Acad. Sci. (U.S.A.) 89: 4549.
The adenovirus, oncoproteins E1a, disrupts the pRB/E2F complex resulting in activation of E2F. However, neoplastic or normal dividing cells lacking sufficient functional pRB to complex E2F will not require the presence of a functional oncoprotein, such as E1a, to possess transcriptionally active E2F. Therefore, it is believed that replication deficient adenovirus species which lack the capacity to complex RB but substantially retain other essential replicative functions will exhibit a replication phenotype in cells which are deficient in RB function (e.g., normal dividing cells, or cells which are homozygous or heterozygous for substantially deleted RB alleles, cells which comprise RB alleles encoding mutant RB proteins which are essentially nonfunctional, cells which comprise mutations that result in a lack of function of an RB protein) but will not substantially exhibit a replicative phenotype in non-replicating, non-neoplastic cells. Such replication deficient adenovirus species are referred to as E1a-RB(−) replication deficient adenoviruses.
A cell population (such as a mixed cell culture or a human cancer patient) which comprises a subpopulation of neoplastic cells and dividing normal cells both lacking RB function, and a subpopulation of non-dividing, non-neoplastic cells which express essentially normal RB function can be contacted under infective conditions (i.e., conditions suitable for adenoviral infection of the cell population, typically physiological conditions) with a composition comprising an infectious dosage of a E1a-RB(−) replication deficient adenovirus. This results in an infection of the cell population with the E1a-RB(−) replication deficient adenovirus. The infection produces preferential expression of a replication phenotype in a significant fraction of the cells comprising the subpopulation of neoplastic and dividing normal cells lacking RB function (RB− cell) but does not produce a substantial expression of a replicative phenotype in the subpopulation of non-dividing neoplastic cells having essentially normal RB function. The expression of a replication phenotype in an infected RB(−) cell (neoplastic or dividing normal cells) results in the death of the cell, such as by cytopathic effect (CPE), cell lysis, apoptosis, and the like, resulting in a selective ablation of such RB(−) cells from the cell population. See, U.S. Pat. Nos. 5,801,029 and 5,972,706.
Typically, E1a-RB(−) replication deficient adenovirus constructs suitable for selective killing of RB(−) neoplastic cells comprise mutations (e.g., deletions, substitutions, frameshifts) which inactivate the ability of an E1a polypeptide to bind RB protein effectively. Such inactivating mutations typically occur in the E1a CR1 domain (amino acids 30-85 in Ad5: nucleotide positions 697-790) and/or the CR2 domain (amino acids 120-139 in Ad5; nucleotide positions 920-967), which are involved in binding the p105 RB protein and the p107 protein. Preferably, the CR3 domain (spanning amino acids 150-186) remains and is expressed as a truncated p289R polypeptide and is functional in transactivation of adenoviral early genes. FIG. 1 portrays schematically the domain structure of the E1a-289R polypeptide.
In addition to alterations in the E1 a region of adenovirus, it would be desirable to enhance viral specific killing of neoplastic cells that lack RB function by constructing viruses that have critical replicative functions under the control of transcriptionally active E2F. The adenovirus replication cycle has two phases: an early phase, during which 4 transcription units E1, E2, E3, and E4 are expressed, and a late phase which occurs after the onset of viral DNA synthesis when late transcripts are expressed primarily from the major late promoter (MLP). The late messages encode most of the virus's structural proteins. The gene products of E1, E2 and E4 are responsible for transcriptional activation, cell transformation, viral DNA replication, as well as other viral functions, and are necessary for viral growth. See, Halbert, D. N., et al., 1985, J Virol. 56:250-7.
If the adenoviral regions that are involved in virus replication could be brought under the control of E2F via an E2F responsive transcriptional unit, this would provide an enhanced adenovirus that selectively kills neoplastic cells that lack RB function, but not normal cells.
By way of background, the following references are presented relating to adenoviral vectors with alterations in regions involved in viral replication, including the E4 region, and E2F responsive promoters.
WO 98/091563, inventors Branton et al., presents methods and compositions for using adenoviral E4 proteins for inducing cell death.
Gao, G-P., et al., describe the use of adenoviral vectors with E1 and E4 deletions for liver-directed gene therapy. See, J. Virology, December 1996, p. 8934-8943.
WO 98/46779 describes certain adenoviral vectors capable of expressing a transgene comprising a modified E4 region but retaining E4orf3.
Yeh, P., et al describe the expression of a minimal E4 functional unit in 293 cells which permit efficient dual trans-complementation of adenoviral E1 and E4 regions. See, Yeh, P., et al J. Virology, January 1996, pages 559-565.
U.S. Pat. No. 5,885,833 describes nucleic acid constructs comprising an activator sequence, a promoter module, and a structural gene. The promoter module comprises a CHR region and a nucleic acid sequence that binds a protein of the E2F family.
Wang, Q. et al., in Gene Ther. 2:775-83 (1995) describe a 293 packaging cell line for propagation of recombinant adenovirus vectors that lack E1 and/or E4 regions. To avoid the transactivation effects of the E1A gene product in parental 293 cells as well as the over expression of the E4 genes, the E4 promoter was replaced by a cellular inducible hormone gene promoter, the mouse alpha inhibin promoter. Krougliak and Graham describe the development of cell lines that express adenovirus type 5 E1, E4, and pIX genes, and thus are able to complement replication of adenovirus mutants defective in each of these regions. See, Krougliak, V. and Graham, F., Human Gene Therapy, vol. 6: p. 1575-1586, 1995. Fang, B., et al. in J. Virol. 71:4798-803 (1997) describe an attenuated, replication incompetent, adenoviral vector that has the E4 promoter replaced with a synthetic GALA/VP16 promoter that facilitates packaging of the adenoviral vector in 293 cells that stably express the GAL4/VP16 transactivator. The virus was made replication incompetent by deletion of the E1 region of the virus.
U.S. Pat. No. 5,670,488 describes adenoviral vectors having one or more of the E4 open reading frames deleted, but retaining sufficient E4 sequences to promote virus replication in vitro, and having a DNA sequence of interest operably linked to expression control sequences and inserted into the adenoviral genome.
U.S. Pat. No. 5,882,877 describes adenoviral vectors having the E1, E2, E3 and E4 regions and late genes of the adenovirus genome deleted and additionally comprising a nucleic acid of interest operably linked to expression control sequences.
WO 98/13508 describes selectively targeting malignant cells using an E2F responsive promoter operably linked to a transgene of interest.
Neuman, E., et al., show that the transcription of the E2F-1 gene is rendered cell cycle dependent by E2F DNA-binding sites within its promoter. See, Mol Cell Biol. 15:4660 (1995). Neuman, E., et al also show the structure and partial genomic sequence of the human E2F1 gene. See, Gene. 173:163-9 (1996).
Parr, M. J., et al., show that tumor-selective transgene expression in vivo is mediated by an E2F-responsive adenoviral vector. See, Nat Med. 3:1145-9 (1996). Adams, P. D., and W. G. Kaelin, Jr. show transcriptional control by E2F. See, Semin Cancer Biol. 6:99-108 (1995).
Hallenbeck, P., et al., describe vectors for tissue-specific replication. One such vector is adenovirus that is stated to selectively replicate in a target tissue to provide a therapeutic benefit from the vector per se, or from heterologous gene products expressed from the vector. In the former instance a tissue-specific transcriptional regulatory sequence is operably linked to a coding region of a gene that is essential for replication of the vector. Several coding regions are described including E1a, E1B, E2 and E4. See, WO 96/17053 and WO 96/17053.
Henderson, et al., in U.S. Pat. No. 5,698,443 shows an adenovirus vector having at least one of the genes E1A, E1B or E4 under the transcriptional control of a prostate cell specific response element.
It should be apparent that viruses offer another means for treating cancer. Thus, viruses that selectively replicate in, and kill neoplastic cells would be an invaluable weapon in a physician's arsenal in the battle against cancer.


A bottle capping and pressurizing device for capping and pressurizing a bottle containing an effervescent beverage, the bottle capping and pressurizing device including a housing member, the housing member substantially enclosing a chamber, a piston slidably within the chamber, an attachment apparatus for attaching the housing member to the bottle, the attachment apparatus including a capping surface for covering the mouth of the bottle, a passage leading from the interior of the chamber to the capping surface, and a one way flow valve for transferring air through the passage solely in a direction from the interior of the chamber to the capping surface, the one way flow valve including a flexible diaphragm overlaying the capping surface and at least one slit provided in the flexible diaphragm.

1. Field of the Invention
The present invention relates to a device for capping and pressurizing a bottle that contains an effervescent beverage, such as a carbonated soda or a sparkling wine.
2. Description of the Related Art
Carbonated sodas are increasingly being marketed in two and/or three liter bottles, most commonly plastic bottles. This can create a problem, since the beverage tends to go "flat" if the entire contents of the bottle are not consumed soon after opening. The problem is exacerbated with larger size bottles, both since the contents take longer to consume, and since more of an air pocket is created into which the carbonated gases can escape.
U.S. Pat. No. 4,763,803 relates to a stopper for a bottle that is adapted to be used with a pump for evacuating air from the bottle to preserve wine, or for increasing the pressure in the bottle to maintain the carbon dioxide content in a soft drink. A separate pump is required to evacuate air from or compress air into the bottle.
U.S. Pat. No. 4,524,877 relates to a pressurizing and closure apparatus having a hand pump that extends downward that extends downward into the neck of a bottle.
U.S. Pat. No. 4,033,091 relates to a carbonated beverage container closure apparatus to which a bellows type pump is threadingly engaged for introducing compressed air into the container, the bellows type pump then being removed from the closure device.
U.S. Pat. No. 4,842,151 similarly relates to a bellows type pump that is engaged with and disengaged from a bottle closure apparatus. A coupling device is employed to realize the engagement and disengagement function.
Finally, U.S. Pat. No. 4,640,426 relates to a bottle cap for closing and for pressurizing an opened bottle, the bottle cap including a body adapted to close over the mouth of the bottle and a resilient manually compressible and relaxable bulb mounted to the body.


An antenna system (308, 309, 310, 312, 314, 316, and 317) for a wrist carried selective call receiver (300) comprises at least first (312 and 314) and second (310) elements, coupled to each other and coupled to the selective call receiver to form a first single magnetic loop antenna (312, 308, 316, and 310) having a first physical orientation. At least one of the first and second elements comprises at least one second single magnetic loop antenna (312, 308, 316, 310, 317, 309, and 314) also coupled to the selective call receiver. The second single magnetic loop antenna has a second physical orientation different from the first physical orientation.

In portable radio receivers and especially in selective call receivers and related applications, size and weight are extremely important factors. In the past, many selective call receivers have used antenna systems that have tended to increase the size and weight of the receivers significantly. As compactness and light weight have become more important in the design of modern selective call receivers, compact and light weight antenna systems also have become more important.
The need for small size and weight is particularly strong in a selective call receiver designed to be carried on the wrist. However, a degradation in antenna system performance to achieve size and weight reduction is not desirable. Furthermore, a wrist carried selective call receiver is operated in many different positions. It may be held in front of the face, at the side of the human body, outstretched from the body, or placed on various conducting and non-conducting surfaces. A wrist carried selective call receiver thus must be designed for acceptable receive sensitivity in many possible body positions.
Conventional wrist carried receivers have used serpentine loop antennae or simple loop antennae that are responsive to the magnetic field component of a transmitted radio frequency (RF) signal. One such antenna system is shown in U.S. Pat. No. 3,032,651 to Gisiger-Stahli et al. This type of antenna system provided marginal performance but was desirable because the antenna elements could be concealed within the wrist band housing. The performance of simple loop antennae was particularly poor for certain body positions in which the magnetic field of the transmitted RF signal was parallel to the plane of the loop.
An improvement to the single loop antenna design is shown in U.S. Pat. No. 4,873,527 to Tan. The improvement comprises a "combo" design incorporating a ferrite core loop antenna connected in series with a single magnetic loop antenna. The axes of the two antennae were orthogonal to one another, resulting in a reduction in susceptibility to performance variation caused by changes in body position. While the "combo" design performed better than the single loop design, there were size and weight tradeoffs that limited its performance. Because the ferrite core loop antenna had to fit within the housing of the selective call receiver, it had to be small and light. A small ferrite core antenna, though, would be less sensitive than one with a larger cross-sectional area. The result invariably was either a selective call receiver that was larger than desired, or a design whose susceptibility to performance variation caused by changes in body position was more than desired.
A further problem with the "combo" design resulted from the fact that the ferrite core loop antenna and the single magnetic loop antenna were connected in series. The single magnetic loop antenna consisted of two elements that became separated whenever the wristband clasp was opened, e.g., to remove the wrist carried selective call receiver. Opening the clasp would thus also open the entire antenna system, substantially reducing its performance. Reduced performance with the clasp open is undesirable in the wrist carried selective call receiver, because some users might want to continue operating the selective call receiver while not actually wearing it about the wrist.
What therefore is needed is an antenna system for a wrist carried selective call receiver that eliminates the space consuming ferrite core loop antenna while maintaining antenna performance in many possible body positions. An antenna system that continues to function when the selective call receiver is removed from the wrist with the clasp open also is desirable.

Antenna system for a wrist carried selective call receiver