Methods and apparatus for extracting sample components from complex matrices using supercritical fluid as the principal extracting solvent are disclosed. The invention takes advantage of the fact that the solvent power of a supercritical fluid is stepwise settable by the parameters of density, modifier concentration, and temperature. Accordingly, methods and apparatus for extracting a component from a sample using fluid flow system having a variable and controllable flow restriction are disclosed. The methods of the present invention comprise the steps of inserting the sample into the sample container section, inputting temperature, pressure, flow rate and extraction time set points. Flow rate is controlled and system pressure regulated by the variable flow restriction. The output stream from the extraction is then expanded through a nozzle and into a trap. In certain embodiments, the trap is filled with chemically active packing material. In other embodiments, a fractionation zone and other analytical instruments are coupled to the apparatus of the present invention. Methods and apparatus for rinsing the extraction instrument and for diluting the extraction fluid are also disclosed. Methods for operating a supercritical fluid extraction systems comprising a pressure and thermal control systems which are programmable to regulate the system to maintain such values within the design specifications during the extraction process.

Supercritical fluids can be used as solvents in extraction instruments, chromatographs and other related instruments. The supercritical region is often defined by all temperatures and pressures above the critical temperature and pressure. The critical temperature is that temperature above which the distinction between gases and liquids disappears; there is one fluid phase for all pressures. No matter how much pressure is applied, a liquid phase cannot be condensed. A supercritical fluid can be defined as a substance at a temperature above its critical temperature, and the critical pressure can be defined as the pressure corresponding to the critical temperature value when the values at which a liquid and gas coexist for a substance are plotted on a pressure-temperature graph. Thus, the absence of the possibility of gas-liquid equilibrium is often used to define a supercritical fluid. Supercritical fluids are a useful hybrid of gases and liquids as we commonly perceive them, possessing gas-like viscosities, liquid-like densities, and diffusivities greater than typical liquid solvents. The liquid-like density of a supercritical fluid imparts a variable liquid-like solvent power which is essentially a linear function of density over significant ranges in density. This allows the solvent power, usually considered a chemical interaction, to be set ("dialed in") simply by adjusting a physical parameter, namely density or pressure. Variable solvent power is most pronounced over densities corresponding to pressures from about 0.8 times the critical pressure to pressures at which the solvent densities become nearly liquid-like.
Another important aspect of supercritical fluids is that compared to typical liquid solvents the supercritical fluid transport properties of viscosity and diffusivity allow enhanced mass transport within complex matrices, such as coal, plant or animal tissue, or packed beds. In other words, supercritical fluids penetrate better and dissolve almost as well as typical liquids. Therefore, supercritical fluids are more efficient to use for extractions of complex matrices.
Even though the solvent power of a supercritical fluid is variable, each supercritical fluid has a maximum solvent power approaching that of the substance as a liquid. Although the solvent power of a liquid is also variable and also essentially a linear function of the density, far larger increases in pressure are necessary to produce significant increases in liquid solvent power. For a typical laboratory liquid solvent such as methanol, the pressure can be lowered to atmospheric and a solution of solvent and solute is stable. Heat must be supplied to drive off solvent for solution concentration or solute drying. If a liquid with a very high vapor pressure at ambient temperatures is used, such as liquid carbon dioxide or ammonia, the solvent is readily evaporated upon solution decompression, leaving a dry, concentrated solute. However, there is a discontinuity in the density along an isotherm corresponding to the lines between coexisting liquid and gaseous phases. Because of the discontinuity in density solvent power essentially is made high or low, e.g., "go" or "no-go", and most of the versatility in solvent power control is lost.
In terms of mass transport properties, diffusivity is an important parameter. Liquid diffusivities cover a large range, some of which (e.g., carbon dioxide and ammonia) are almost the same as those of the supercritical fluid when the liquid is at near critical conditions. In those cases either the liquid or the supercritical fluid would suffice for efficient extraction. However, for commonly used liquids, the diffusivities are lower by a factor of 10 to 100 than for supercritical fluids and therefore these liquids are less efficient in terms of the time required for extraction.
Supercritical solvents are therefore superior in that they (1) allow a large continuous range of solvent powers, thus providing for selective solvation of solutes over that range, (2) provide a means of rapid and complete solvent/solute separation with minimal heat input, and (3) can decrease the time for extraction of complex matrices by a factor of 10 to 100.
Carbon dioxide is the principal extracting fluid used in supercritical fluid extraction systems since it is cheap, innocuous, readily available at high purities, and has a critical temperature of about 31.degree. C. making it useful for thermally labile compounds. Furthermore, it is mutually soluble with many common liquid solvents. It has been found that carbon dioxide has a solvent power similar to that of hexane. However, many applications exist which require greater solvent power, the advantageous properties of supercritical fluids, and mild operating temperatures for thermally labile compounds. Mixtures of carbon dioxide plus modifiers can meet these requirements. As well known to those of ordinary skill, supercritical fluids can be used as solvents in extractions and chromatography; in such applications carbon dioxide is the preferred solvent. Other fluids which have critical points near ambient temperature (25.degree. C.) such as ethane, nitrous oxide, ethylener or sulfur hexafluoride could also function as the base solvent. The capability to utilize these alternatives is preferably not exploited because of the inherent danger and greater expense associated with using these solvents.
Another way to increase the solute solubility in supercritical fluid systems is through temperature control. It has been demonstrated that for some solutes a certain minimum temperature is necessary for appreciable solute solubility in a supercritical fluid, even at maximum densities, so temperature is also a solvent power parameter beyond the simple P-T relationship with density.
The problem encountered in building extraction systems which use compressible fluids at pressures above atmospheric (ambient) is that the pressure of the fluid system is coupled with the mass flow rate of the flowing fluid. This is a result of the use of restrictors having constant geometry to achieve a pressure drop from higher pressures to lower pressures which are normally, but not restricted to ambient or vacuum conditions, so that the only practical way to achieve higher pressures upstream of the restriction is to increase the mass flow rate. Alternatively, to maintain the same mass flow rate at higher pressures, a fixed geometry restrictor of smaller dimensions can be substituted; however, such a substitution requires a physical intervention of some kind. However, in operating these extraction systems it is highly desirable to have the same mass flow rate at all pressures, i.e., with the lower flow rates to achieve-lower pressures, the time to flow a chosen net amount of fluid can be significantly longer than at higher pressures, e.g., hours vs. minutes. Therefore, in a system which can be adjusted to operate sequentially at multiple pressures (e.g., 1100 psi, 1300 psi, 1500 psi, 3000 psi, 6000 psi) at flow rates which provide the same integrated mass of expanded carrier fluid at each pressure setting the time to complete the method can be so long that the method becomes inefficient. This is particularly true in operating supercritical fluid extraction systems, as well as near-critical fluid extraction, which can be more efficient in time than extractions using conventional fluids, due to the transport properties (e.g., viscosity, diffusivity) of critical and near-critical fluids. However, that efficiency is lost when the parameters of pressure and flow cannot be decoupled because of the hardware implementation, e.g., constant geometry flow restrictions.
It is therefore an object of the present invention to decouple the pressure and flow parameters so that they can be set and controlled independently.
In the past, operators of supercritical fluid chromatograph (SFC) and supercritical fluid extractor (SFE) instruments selected pressure and temperature parameters to set the desired density parameter indirectly. Density is usually a more meaningful parameter than pressure in supercritical (and near-critical) systems due to its simple linear relationship to the fluid's solvent power. Often, in any previous implementations of supercritical fluid systems, only pressure and temperature inputs have been allowed; calculating the resultant density or even understanding the pressure/density/temperature relationship has been left to the user, albeit occasionally prompted by abbreviated look-up tables. Therefore, in those cases, controlling the solvency has relied upon the technical sophistication and persistence of the user to apply equations of state appropriately.
The extraction of solids has typically been done manually in conventional laboratory glassware. Laboratory devices which automate the steeping of the sample in a boiling liquid solvent along with the subsequent concentration of the resultant solution are sold commercially as the "Soxtec" by Tecator. This device does not permit fractionation as part of the method; the output is not in autosampler-compatible vessels and samples are boiled at temperatures determined by the boiling points of the extracting solvents, which can be detrimental to thermally labile compounds. Recently, several companies have offered instruments based on using supercritical fluids: Milton Roy, Suprex, CCS, Lee Scientific/Dionex, and Jasco. The implementations by these companies are not exceptionally sophisticated or automated; they require various degrees of manual intervention. In these implementations, the full capability of using supercritical fluids for quantitative extraction is not realized
Thus, there exists a long-felt need to design an instrument which could be used to isolate various materials from solid samples using supercritical fluid technology. Either the isolated materials (extract) or the material remaining (raffinate) could be of interest. The process of isolation is referred to as extraction. The need also exists to automate the extraction of solids, since the procedures are typically manually intensive. In the business of preparing samples for analytical instruments, it would be highly desirable to automate sample preparation of raw samples to obtain a form compatible with introduction into typical analytical instruments used in laboratories worldwide. The extraction of solids is often accompanied by other manipulations such as fractionation (e.g., by column chromatography), concentration, solvent exchange, and reconstitution. A method comprised of these generic manipulations may actually consist of many (ranging from several to hundreds) of manual steps. It would therefore be desirable to produce an instrument which replaced the above-mentioned generic manipulations so that the only step required was to present a sample to the extraction instrument and receive fractions of isolated material in vessels compatible with the autosamplers of analytical instruments.
Improvements in the isolation of selected material from solid samples and the automation of the generic manipulations of processes such as extraction, fractionation, concentration, solvent exchange, and reconstitution are clearly desirable goals. It would be desirable and of considerable advantage to use a technique different from the traditional laboratory manipulations known to those of ordinary skill if such a different technique provided superior performance in any of the following areas: quantitation, repeatability and reproducibility, speed, automation, automatability, health hazard reduction, or cost reduction (materials and labor).
Ideally, an extraction instrument would be a stand alone module, that is, a component instrument within an integrated system. In such systems it is also highly desirable to provide robotic accessibility for inputting the sample and retrieving the fraction in an automated fashion. An important aspect of any extraction system therefore lies in its upgradability for automating the sample input (i.e., adding an autosampler for solid samples) and automating the fraction output (i.e., fraction collection with further chemical manipulation and large-scale queuing); an external pump module for blending extraction fluid composition could also be a future addition.
Another improvement in the utility of extraction systems would be the use of standard input and output containers for the sample which is input and the fraction solutions which are output. The instrument would accordingly be provided with a multiple sized extraction chamber which accepts the solid samples.
An improved extraction instrument would also incorporate an automated "method", with a, method being defined as that sequence of manipulations associated with any one sample. Examples include, but are not limited to, valve actuation, thermal zone setpoint changes, extraction fluid solvent selection, reconstitution solvent selection, flow path selection, fraction output destination, density/pressure setpoint changes, flow rate setpoint changes. Such an automated extraction instrument would also provide automatic selectable output destinations within a method, and from method to method; automatic selectable inputted extraction fluid composition within a method and from method to method; and automatic selectable rinse solvents for the solvent exchange/reconstitution emulation processes within a method and from method to method.

Decoupled flow and pressure setpoints in an extraction instrument using compressible fluids


In a vehicle brake having a brake piston accommodated in a housing, a blocking device for securing the brake piston inside the housing and an actuating device for controlling the blocking device, it is provided that the brake piston together with the housing delimits a fluid chamber, which is chargeable with hydraulic fluid, so that the brake piston for actuating the vehicle brake is displaceable hydraulically inside the housing along a piston longitudinal axis, that moreover the blocking device comprises a ramp arrangement and a blocking element that is displaceable relative to the housing, and that by means of the actuating device the blocking element in interaction with the ramp arrangement for securing the brake piston inside the housing is displaceable and connectable to the brake piston. In this vehicle brake, it is further provided that the actuating device comprises a motor drive, which is drive-connected to the ramp arrangement, wherein the blocking element upon activation of the motor drive is displaced to secure and release the brake piston inside the housing.

A feature of the present invention is to provide a vehicle brake of the initially described type, which is comfortably actuable to activate the parking braking function and with which higher clamping forces may be summoned up to guarantee a reliable parking braking function.
This feature is achieved by a vehicle brake of the initially described type, in which the actuating device comprises a motor drive, which is drive-connected to the ramp arrangement in such a way that the blocking element upon activation of the motor drive is displaced to secure and release the brake piston inside the housing.
According to the invention, the vehicle brake is accordingly equipped with a motor-driven actuating device, which makes it superfluous for the driver to summon up in an uncomfortable and purely mechanical manner the clamping force needed to activate the parking braking function. Rather, an activation of the parking braking function may be effected electronically, i.e. by pressing a button or through automatic recognition of an operating situation. The vehicle brake according to the invention moreover allows the actual displacement of the brake piston plus its brake lining to be effected hydraulically also upon activation of the parking braking function and—where necessary—allows the actuating device to cause merely a clamping force increase in addition to the hydraulically generated clamping force. The blocking device additionally has the function of securing the brake piston in its axial position achieved as a result of the hydraulic displacement, thereby making it possible to maintain a sufficiently high clamping force, which, even in the event of elasticity-induced and thermally induced dimensional changes of the components involved in the clamping path, guarantees a reliable parking braking function.
With regard to the motor drive, it may be provided that it takes the form of a rotary drive, for example a conventional rotary electric motor may be used. Proceeding from this development of the invention, it may be provided that the actuating device comprises an eccentric arrangement, by means of which the motor drive is connected to the ramp arrangement. In said case, the eccentric arrangement may comprise an eccentric disc connected to the motor drive as well as a swivelling lever connected to the ramp arrangement, wherein the swivelling lever upon activation of the motor drive slides on the eccentric disc and in so doing swivels. By suitably selecting the shape of the eccentric disc and of the external contour of the swivelling lever, a desired clamping force characteristic may be achieved. In a development of the invention, it is possible for the external contour of the eccentric disc and of the swivelling lever to have contour portions, which in a state of mutual abutment lock eccentric disc and swivelling lever relative to one another, thereby preventing unintentional cancellation of the parking braking function.
Instead of a rotary drive, the motor drive may take the form of a linear drive. This may be achieved for example by connecting a rotary drive to a threaded mechanism that converts the rotational movement to a linear movement. Given the use of a linear drive, a development of the invention provides that the actuating device comprises a lever arrangement, by means of which the motor drive is connected to the ramp arrangement.
The motor drive may comprise an electric motor. It is equally possible for the motor drive—when in the form of a linear drive—to comprise a solenoid. The construction of the motor drive in the form of a hydraulic motor, particularly in the form of a hydraulically controllable piston/cylinder arrangement, is also possible within the framework of the invention.
With regard to the ramp arrangement, it may be provided that it comprises at least one first ramp surface, which is provided on the housing or connected thereto in a rotationally fixed manner, and at least one second ramp surface formed on a ramp component, which is displaceable relative to the housing and connected to the blocking element, wherein upon activation of the motor drive the two ramp surfaces slide on one another to displace the blocking element. In a development of this idea, the invention provides that between the at least one first ramp surface and the at least one second ramp surface rolling bodies are provided, via which the at least one first ramp surface is in contact with the at least one second ramp surface. Upon activation of the motor drive, such a ramp arrangement behaves in such a way that the second ramp surface, which is displaceable relative to the housing, executes an axial movement relative to the housing. This axial movement may be used to displace the brake piston in the direction of its piston longitudinal axis and hence load it towards a brake disc. Preferably, a plurality of complementary ramp surfaces interact, which are formed in a complementary manner on the housing and on the ramp component respectively. Suitable rolling bodies are, for example, balls or rollers.
With regard to operation of the vehicle brake according to the invention, it is provided that in a service braking situation the brake piston is displaceable inside the housing by charging the fluid chamber with hydraulic fluid and discharging hydraulic fluid from the fluid chamber and that in a parking braking situation first the brake piston is displaced inside the housing by charging the fluid chamber with hydraulic fluid, then the actuating device is actuated to secure the brake piston, wherein the blocking element is fed towards the brake piston, and finally for a pressure reduction in the fluid chamber hydraulic fluid is discharged from the fluid chamber. It may further be provided that to cancel the parking braking situation the fluid chamber is charged with hydraulic fluid until the blocking element is released by the brake piston, then the blocking element is removed from the brake piston by means of the blocking device and finally for a pressure reduction in the fluid chamber hydraulic fluid is discharged from the fluid chamber. Thus, to activate the parking braking function it is possible to use the clamping force summoned up by a hydraulic actuation and displacement of the brake piston for placing and clamping the brake lining onto the brake disc. In addition, the clamping force summoned up by the actuating device may be additively superimposed on the hydraulically summoned-up clamping force. In this way, progressively and without a significant expenditure of force having to be summoned up mechanically by the driver, a higher clamping force is achieved for the parking braking situation than was described previously with regard to the background art according to EP 0 403 635 B1. The hydraulic pressure in the fluid chamber is then reduced to zero. In said case, the brake piston moves back slightly in the direction of its initial position.
With regard to the arising axial forces, in a development of the invention it is provided that in terms of magnitude the axial force component, which is mechanically exerted on the brake piston in addition to the hydraulically generated axial force component upon actuation of the actuating device, is greater than or equal to a minimum axial force, by which the axial force exerted by the brake piston on a component to be braked is reduced after the brake piston has been secured and the hydraulic fluid discharged from the fluid chamber. The clamping force is therefore, after the discharge of hydraulic fluid from the fluid chamber, still high enough to be able to guarantee a reliable parking braking effect. Even in the event of thermally induced dimensional changes, such as may occur for example when the individual vehicle brake components involved in the clamping path cool down at the end of an extended period of travel, or in the event of elastic deformations under load and subsequent relaxation, the clamping force summoned up according to the invention is still high enough to be able to guarantee a reliable parking braking effect.
To cancel the parking braking situation, in the previously described variant of the invention it is necessary to charge the fluid chamber anew with hydraulic fluid and hence cancel a mechanical connection between brake piston and blocking device. The actuating device may then be correspondingly controlled and the blocking element may move back into its initial position, in which it releases the brake piston. Hydraulic fluid may then be discharged from the fluid chamber, so that the brake piston may move back into a braking-effect-free initial position. As an alternative to such a procedure, with a motor drive of a sufficiently powerful design it is also possible, without a renewed feed of hydraulic fluid, to move the blocking element back into its initial position and accordingly release the brake piston, so that the brake piston may adopt its braking-effect-free position.
The invention further relates to a method of actuating a vehicle brake of the previously described type, wherein in a service braking situation the brake piston is displaced inside the housing by feeding hydraulic fluid to the fluid chamber or discharging hydraulic fluid from the fluid chamber, and that in a parking braking situation first the brake piston is displaced inside the housing by charging the fluid chamber with hydraulic fluid, then the actuating device is actuated to secure the brake piston, wherein the blocking element is fed towards the brake piston and presses thereon, and finally for a pressure reduction in the fluid chamber hydraulic fluid is discharged from the fluid chamber. In said case, it may be provided that the axial force component, which is mechanically exerted on the brake piston in addition to the hydraulically generated axial force component upon actuation of the actuating device, is selected in such a way that in terms of magnitude it is greater than or equal to a minimum axial force, by which the axial force exerted by the brake piston on a component to be braked is reduced after the brake piston has been secured and the hydraulic fluid discharged from the fluid chamber. The minimum axial force may be determined, for example, from the difference of the moduli of elasticity of the components involved in the hydraulic displacement of the brake piston and the components involved in the mechanical actuation of the actuating device.
To cancel the parking braking situation, the fluid chamber is charged with hydraulic fluid until the blocking element is at least partially relieved or released by the brake piston, then the blocking element is removed from the brake piston by means of the blocking device and finally for a pressure reduction in the fluid chamber hydraulic fluid is discharged from the fluid chamber.
Other advantages of this invention will become apparent to those skilled in the art from the following detailed description of the invention, when read in light of the accompanying drawings.


A method establishes a PoC multimedia session for making a PoC multimedia call according to a support attribute of a PoC terminal and sets media for each session. In the method, a message for setting a session management server to split arbitrary PoC user terminals according to an attribute of media to establish the session is transmitted from the arbitrary PoC user terminals to the session management server. An INVITE message according to the media attribute is transmitted from the session management server to each of the terminals based on the setting.

1. Field of the Invention
The present invention relates to technology for splitting multimedia type-specific terminals of a push-to-talk-over-cellular (PoC) system to transmit media.
2. Description of the Related Art
Significant developments in mobile communications technology and the extension of mobile communications networks have resulted in the development of a vast array of services and applications for use with a cellular phone. At the same time, demand among cellular phone users for these additional services, such as a location service, a multimedia service, and a push-to-talk (PTT) service, is increasing. The PTT service supports various supplementary functions such as an instant messenger function and a status display function, as well as a group call and a voice call which are also provided by an existing radio or a trunk radio system (TRS).
Currently, standardization of a push-to-talk-over-cellular (PoC) service that employs the PTT function in a mobile communication network is taking place. A unique feature of the PoC service is that a user can participate in a plurality of PoC sessions and can also use a call service while switching from the PoC sessions as desired. This feature is a requirement that is specified in the open mobile alliance (OMA), which is a forum for specifying mobile communications services.
FIG. 1 is a schematic diagram of a conventional PoC service system. Referring to FIG. 1, a PoC client 10, as a service requester installed in a mobile station, is generally connected to a Session Initiation Protocol/Internet Protocol (SIP/EP) core network 30 that supports SIP and IP multimedia functions via an access network 20.
The PoC client 10 resides in a PoC user terminal to provide access to the PoC service. The PoC client 10 mainly serves to establish, participate in and terminate a PoC session. In addition, the PoC client 10 makes and transfers a talk burst, supports an instant personal alert and performs authentication when accessing the PoC service. Hereinafter, unless otherwise stated, the PoC client 10 is assumed to be the same as a PoC service subscriber or PoC terminal.
The SIP/EP core network 30 is connected to a PoC server 60, a GLMS (Group List and Management System) 50, and a presence server 70 in order to support the PoC service.
Generally, SIP is a standard defined in the IETF (Internet Engineering Task Force) RFC (Request for Comments) 2543. SIP is an application-layer control protocol that is used to set up, modify and terminate a session or call for multimedia communication such as video and voice communication. SIP exists over a UDP (User Datagram Protocol)/TCP/IP layer, which supports both unicast and multicast sessions for initiating a session by inviting participants to a multimedia conference with a client/server protocol capable of exchanging SIP Request and Response messages in a request/response fashion.
The SIP Request message provides six functions in RFC 2543 as follows: INVITE (Invitation to participate in a session), ACK (Acceptance of an INVITE request), BYE (Termination of a call), REGISTER (Registration with a redirect server by a user agent), CANCEL (Cancellation of a pending request), and OPTIONS. The SIP Response message provides status codes as follows: 1xx (Information response), 2xx (Success response), 3xx (Redirection response), 4xx (Client Error, Request Failure), 5xx (Server Error), and 6xx (Global Failure).
The PoC server performs a Controlling PoC Function (CF) of controlling overall maintenance and management of a PoC session and a Participating PoC Function (PF) of controlling maintenance and management between each PoC session, which will be explained below with reference to Tables 1 and 2.
TABLE 1Controlling PoC Function (CF)Provides centralized PoC session handlingProvides centralized Media distributionProvides centralized Talk Burst Arbitration functionality including talkeridentificationProvides SIP session handling, such as SIP session origination,termination, etc.Provides policy enforcement for participation in group sessionsProvides participant informationCollects and provides centralized media quality informationProvides centralized charging reportsMay provide transcoding between different codecsSupports Talk Burst Control Protocol Negotiation
As shown in Table 1, the CF serves to maintain and manage a PoC session. The PoC server receives requests for the floor from PoC clients, arranges an order in which to give the clients the floor, and gives the clients the floor in that order. The PoC server also distributes a talk burst, for which an arbitrary PoC client makes a request, to all other PoC clients participating in a group PoC call, and provides information of the PoC clients participating in the group PoC call.
As shown in Table 2 below, the PF manages a PoC session between the CF and each PoC client. Particularly, the PF relays the floor between the PoC client and the CF when the PoC client makes a request for the floor or when the CF gives the floor to the PoC client. In addition, the PF relays media between the CF and the PoC client, performs transcoding between different codecs, and filters one of two concurrent PoC sessions according to the choice of a PoC user when there is simultaneous talking in the two active PoC sessions.
TABLE 2Participating PoC Function (PF)Provides PoC session handlingMay provide the Media relay function between PoC client and ControllingPoC serverMay provide user media adaptation proceduresMay provide the Talk Burst control message relay function betweenPoC client and Controlling PoC serverProvides SIP session handling, such as SIP session origination,termination, etc, on behalf of the represented PoC client.Provides policy enforcement for incoming PoC session (e.g. accesscontrol, incoming PoCsession barring, availability status, etc.)May collect and provide media quality informationProvides participant charging reportsMay provide filtering of media streams in the case of simultaneoussessionsMay provide transcoding between different codecsMay support Talk Burst Control Protocol NegotiationStores the current Answer Mode and Incoming PoC Session Barringpreferences of the PoC client
In the PoC service system described above, the PoC user can input information on a group and its members to the GLMS 50 through his/her PoC terminal, and can receive information about PoC users whom he or she can call through an individual or group list transmitted from the GLMS 50. Alternatively, the information on the group and its members may be input, modified and managed in the GLMS 50 via a reliable communication network such as the Internet or an Intranet.
In order to use the PoC call service, the PoC user registers his/her PoC address with the SIP/IP core network 30. The SIP/IP core network 30 stores PoC user information at the request of the PoC user. Thus, when another PoC user tries to request a group PoC call, the PoC user registers his/her information in the SIP/IP core network 30 in advance, and requests the group PoC call to his/her SIP/IP core network by using group identification information transmitted from the GLMS 50. At this time, the SIP/IP core network 30 performs address determination and domain location determination by using information of the call requesting PoC user and then transfers a PoC call request to a home PoC server with which the call requesting PoC user is registered. In regard to the PoC call request, the PoC server prepares to establish a PoC session, obtains each user's information from the GLMS, and then transfers a PoC call request signal to a corresponding SIP/IP core network. When a PoC call request is made to users within an Intradomain, the PoC server performs both the CF and PF. The PoC server, which manages a call-requested PoC user, requests a PoC call to the PoC user after the SIP/IP core network performs the locating procedure, by using information of the PoC user that is transmitted to the PoC server.
Features of the PoC system in the OMA are as follows.
The PoC system is divided into an on-demand session mode and a pre-established (or early) session mode, according to the connection with a PoC server within a user's home network.
The pre-established session mode is designed so that the PoC user sets up a session between a PoC client and a PoC server belonging to a PoC user's home network in advance by PoC user's request. The pre-established session enables the PoC user to negotiate media parameters to be used with the PoC server in advance, and thus perform rapid call setup without renegotiating the media parameters to be used in the future between the PoC server and client. In order to set up the pre-established session, the PoC client provides supported media parameters to a Session Description Protocol Multipurpose Internet Mail Extensions (SDP MIME) body through a method of SIP INVITE, and responds to the media parameters provided from the PoC server. The PoC client sends, to the PoC user, identification information of the pre-established session for a response message received from the PoC server, together with a conference Uniform Resource Identifier (URI). When using the pre-established session, it is possible to pre-negotiate such parameters as an IP address, a port number, a codec to be used and a talk burst control protocol.
The on-demand session mode refers to a state in which the PoC user does not set up the pre-established session, and indicates that the PoC user performs a PoC call connecting procedure after receiving an INVITE message of another PoC user.
Meanwhile, the PoC system enables the PoC to make a half-duplex group call in addition to the foregoing features. This multilateral conferencing function is a representative feature of the PoC, and is divided into an ad-hoc PoC group, a pre-arranged PoC group and a chat PoC group according to how it is set up.
In the PoC system having the foregoing features, respective elements such as the PoC client, PoC server, SIP/IP core network, group list server and presence server, as well as procedures of initiating and connecting an initial PoC session through signaling between these elements can be found from the OMA standard draft as the conventional SIP-based technology. Thus, their description will be omitted herein.
A procedure for establishing a PoC multimedia session in the PoC system will be described below. The procedures for session establishment with respect to each PoC group are similar. The same procedure is repeated for all members in order to establish the group session. Hence, the procedure for establishing the PoC multimedia session will be described on the basis of a procedure for establishing the session for one PoC member. To this end, the procedure for establishing the PoC multimedia session will be described with reference to FIGS. 2 and 3. In FIGS. 2 and 3, an originating side requester for a PoC call makes a request for call processing by sending a multimedia invitation message using a SIP protocol (herein, the case of requesting audio and video calls is considered by example). On a terminating side, an auto answer mode is set up, and a pre-established session exists. Under these conditions, call processing procedures of call originating and terminating sides implemented by the prior art are each described.
FIG. 2 shows a signaling flow for a conventional process of connecting the PoC multimedia session of an originating side.
Referring to FIG. 2, a PoC client A sends an INVITE message, which includes the SIP address of a receiver to whom the PoC client A desires to talk, to an SIP/IP core A (S11). At this time, the INVITE message includes elements such as information on the PoC address of a call request client, requested media parameters (since the requested session is based on the multimedia, which has various media attribute values such as an encoding method referring to audio and video, a rate, and a payload type), and information on an attribute value informing PoC service, etc. The INVITE message is transmitted to a PoC server (hereinafter PF A), which controls a participating function via corresponding servers (Proxy Call Session Control Function (P-CSCF) and Serving Call Session Control Function (S-CSCF)) in an IMS network through a route query at a Dynamic Host Configuration Protocol (DHCP) server or DNS server (S12). Since the PF A, to which a PoC user is connected when a general call request is made, can be split from a PoC server X (hereinafter CF X) that manages the talk burst of an established session, the INVITE message forwarded through steps S11 and S12 is transmitted to the CF X via an SIP/IP core network of each network (S13, S14 and S15).
A controlling network including the CF transmits the INVITE request forwarded through step S15 to the corresponding SIP/IP core network, and then receives a response message. An SIP message with which the terminating side network responds may be one of provisional response messages of 1XX, successful response messages of 2XX, and error response messages of 4XX, 5XX and 6XX (herein, the description will be oriented to a normal call processing procedure within a range that does not deviate from the fundamental effect of the present invention). After step S15, the CF can receive an AUTO-ANSWER or OK response according to an answering mode of the terminating side. Alternatively, in the case of the AUTO-ANSWER response of FIG. 2, the CF may receive a signal SIP 183 Session Progress, and thus perform connection between the PoC server and client in the IMS network of the call requester. A call acceptance signal of the receiver is sent as the SIP 183 Session Process or SIP 200 OK response, and forwarded to the PoC client A via the PoC servers of the CF and PF (S16 through S20).
Meanwhile, after receiving the 200 OK or 183 Session Progress response from the PoC server of the terminating side, the CF determines whether a PoC call is connected or not, and then sends a Floor Granted signal that grants the talk burst floor to the PoC client A. Granting the talk burst authority according to the response (200 OK or 183 Session Progress) may be divided into confirmed and unconfirmed types, which explains why the CF requires a buffering function.
After receiving the acknowledgement response signal to the INVITE request signal (S16 through S20), the PoC client A receives the Floor Granted signal in order to forward a talk burst transmission enable signal (ring back tone) using an Real-time Transport Control Protocol(RTCP) protocol (S21 and S22). At this time, the Floor Granted signal is generated from the CF having the authority to arbitrate the talk burst, and transmitted to a corresponding PoC client via the PF, which manages the corresponding PoC client. The Floor Granted signal may be transmitted without passing through the SIP/IP core network since it uses a bearer's route instead of an SIP protocol. The PoC user, who finally confirms the ring back tone, transmits a media stream (e.g. voice) using an Real-time transport protocol (RTP) protocol.
FIG. 3 shows a conventional call processing procedure of the terminating side based on the assumption of successful session establishment when a pre-established session is set up between a server and client of the terminating side in correspondence to the aforementioned call processing procedure of the originating side.
It is assumed that media attribute values between a PoC server and a PoC client that set up a pre-established session make use of designated attribute values with no change when a new session is requested.
An INVITE message received from an originating side network is transmitted to a PoC server belonging to the home network of a terminating PoC client through an SIP/IP core network according to the call processing procedure of an IMS network (S31, S32 and S33). At this time, a PF B sets a setup value of its answering mode in an auto answer mode, and thus transmits an SIP 200 OK message to the originating side network in response to the INVITE request message (S34, S35 and S36). The PF B does not transmit the INVITE message to the PoC client that is connected therewith because it is unnecessary to change the pre-established session.
Meanwhile, the PoC server, CF X, of a controlling network which receives an OK response returned through an IMS route transmits the OK response to the originating PoC client, and thereby completes the PoC call processing procedure (S37), and transmits a Floor Granted signal that grants the talk burst floor, to the originating PoC client (S38). Further, the CF transmits an RTCP signal of granting the floor, and simultaneously transmits a Receiving Talk Burst signal, that includes a PoC address or display name of the PoC user having the floor, to a terminating PoC user (S39 and S40). Thereby, the CF enables a terminating PoC client to receive beforehand sender's information of a media stream to be transmitted in the future. This talk burst transmission signal can be transmitted without passing through the SIP/IP core network because it uses a bearer's route instead of an SIP. Meanwhile, the media (voice) stream that is ultimately sent from the originating side is transmitted to a PoC client B through the bearer's route using an RTP, and thereby the PoC call is initiated.
According to the prior art, the following are technical problems that negatively affect the user.
First, the originating PoC client repeatedly transmits the INVITE message in order to establish the PoC multimedia session.
Second, the originating PoC client separates and transmits audio and video through two independent sessions, each of which has been established. Thus, additional support making it possible to be subject to the same floor control is required. However, the conventional PoC system does not support this function, the creating a need for a technical solution to this problem.
Fourth, in the originating PoC client's position, since the INVITE message is repeatedly transmitted in order to separate the media and then establish the session, a long time is required to obtain the floor.

Method and system for splitting terminals in push-to-talk over cellular network


The present disclosure describes a method for the fabrication of ruthenium conductive structures over cobalt conductive structures. In some embodiments, the method includes forming a first opening in a dielectric layer to expose a first cobalt contact and filling the first opening with ruthenium metal to form a ruthenium contact on the first cobalt contact. The method also includes forming a second opening in the dielectric layer to expose a second cobalt contact and a gate structure and filling the second opening with tungsten to form a tungsten contact on the second cobalt contact and the gate structure. Further, the method includes forming a copper conductive structure on the ruthenium contact and the tungsten contact, where the copper from the copper conductive structure is in contact with the ruthenium metal from the ruthenium contact.

In integrated circuits, conductive structures (e.g., metal contacts, vias, and lines) are electrically coupled to transistor regions, such as a gate electrode and source/drain terminals, to propagate electrical signals from and to the transistors. The conductive structures, depending on the complexity of the integrated circuit, can form multiple layers of metal wiring.

Taiwan Semiconductor Manufacturing Co., Ltd.


In sophisticated approaches for forming high-k metal gate electrode structures in an early manufacturing stage, a threshold adjusting semiconductor alloy may be deposited on the basis of a selective epitaxial growth process without affecting the back side of the substrates. Consequently, any negative effects, such as contamination of substrates and process tools, reduced surface quality of the back side and the like, may be suppressed or reduced by providing a mask material and preserving the material at least during the selective epitaxial growth process.

1. Field of the Invention
Generally, the present disclosure relates to sophisticated integrated circuits including advanced transistor elements that comprise gate structures including a metal-containing electrode and a high-k gate dielectric.
2. Description of the Related Art
The fabrication of advanced integrated circuits, such as CPUs, storage devices, ASICs (application specific integrated circuits) and the like, requires a large number of circuit elements to be formed on a given chip area according to a specified circuit layout, wherein field effect transistors represent one important type of circuit element that substantially determines performance of the integrated circuits. Generally, a plurality of process technologies are currently practiced, wherein, for many types of complex circuitry, including field effect transistors, CMOS technology is currently one of the most promising approaches due to the superior characteristics in view of operating speed and/or power consumption and/or cost efficiency. During the fabrication of complex integrated circuits using, for instance, CMOS technology, millions of transistors, i.e., N-channel transistors and P-channel transistors, are formed on a substrate including a crystalline semiconductor layer. A field effect transistor, irrespective of whether an N-channel transistor or a P-channel transistor is considered, typically comprises so-called PN junctions that are formed by an interface defined by highly doped regions, referred to as drain and source regions, and a slightly doped or non-doped region, such as a channel region, disposed adjacent to the highly doped regions. In a field effect transistor, the conductivity of the channel region, i.e., the drive current capability of the conductive channel, is controlled by a gate electrode formed adjacent to the channel region and separated therefrom by a thin insulating layer. The conductivity of the channel region, upon formation of a conductive channel due to the application of an appropriate control voltage to the gate electrode, depends on, among other things, the distance between the source and drain regions, which is also referred to as channel length. Hence, in combination with the capability of rapidly creating a conductive channel below the insulating layer upon application of the control voltage to the gate electrode, the conductivity of the channel region substantially affects the performance of MOS transistors. Thus, as the speed of creating the channel, which depends on the conductivity of the gate electrode, and the channel resistivity substantially determine the transistor characteristics, the scaling of the channel length, and associated therewith the reduction of channel resistivity and reduction of gate resistivity, is a dominant design criterion for accomplishing an increase in the operating speed of the integrated circuits.
Presently, the vast majority of integrated circuits are fabricated on the basis of silicon due to the substantially unlimited availability thereof, the well-understood characteristics of silicon and related materials and processes and the experience gathered over the last 50 years. Therefore, silicon will likely remain the material of choice in the foreseeable future for circuit generations designed for mass products. One reason for the importance of silicon in fabricating semiconductor devices has been the superior characteristics of a silicon/silicon dioxide interface that allows reliable electrical insulation of different regions from each other. The silicon/silicon dioxide interface is stable at high temperatures and, thus, allows the performance of subsequent high temperature processes, as are required, for example, for anneal cycles to activate dopants and to cure crystal damage without sacrificing the electrical characteristics of the interface.
For the reasons pointed out above, in field effect transistors, silicon dioxide is preferably used as a base material for a gate insulation layer that separates the gate electrode, frequently comprised of polysilicon, from the silicon channel region. In steadily improving device performance of field effect transistors, the length of the channel region has been continuously decreased to improve switching speed and drive current capability. Since the transistor performance is controlled by the voltage supplied to the gate electrode to invert the surface of the channel region to a sufficiently high charge density for providing the desired drive current for a given supply voltage, a certain degree of capacitive coupling, provided by the capacitor formed by the gate electrode, the channel region and the silicon dioxide disposed therebetween, has to be maintained. It turns out that decreasing the channel length requires an increased capacitive coupling to avoid the so-called short channel behavior during transistor operation. The short channel behavior may lead to an increased leakage current and to a pronounced dependence of the threshold voltage on the channel length. Aggressively scaled transistor devices with a relatively low supply voltage and thus reduced threshold voltage may suffer from an exponential increase of the leakage current due to the required enhanced capacitive coupling of the gate electrode to the channel region that is accomplished by decreasing the thickness of the silicon dioxide layer. For example, in high performance transistors, a channel length of approximately 0.08 μm may require a gate dielectric made of silicon dioxide as thin as approximately 1.2 nm. Although, generally, usage of high speed transistor elements having an extremely short channel may be restricted to high speed signal paths, whereas transistor elements with a longer channel may be used for less critical signal paths, the relatively high leakage current caused by direct tunneling of charge carriers through an ultra-thin silicon dioxide gate insulation layer may reach values for an oxide thickness in the range of 1-2 nm that may no longer be compatible with requirements for many types of integrated circuits.
Therefore, replacing silicon dioxide, or at least a part thereof, as the material for gate insulation layers has been considered. Possible alternative dielectrics include materials that exhibit a significantly higher permittivity so that a physically greater thickness of a correspondingly formed gate insulation layer nevertheless provides a capacitive coupling that would be obtained by an extremely thin silicon dioxide layer. It has thus been suggested to replace silicon dioxide with high permittivity materials, such as tantalum oxide (Ta2O5), strontium titanium oxide (SrTiO3), hafnium oxide (HfO2), HfSiO, zirconium oxide (ZrO2) and the like.
When advancing to a sophisticated gate architecture based on high-k dielectrics, additionally, transistor performance may also be increased by providing an appropriate conductive material for the gate electrode to replace the usually used polysilicon material, since polysilicon may suffer from charge carrier depletion at the vicinity of the interface to the gate dielectric, thereby reducing the effective capacitance between the channel region and the gate electrode. Thus, a gate stack has been suggested in which a high-k dielectric material provides enhanced capacitance even at a less critical thickness compared to a silicon dioxide layer, while additionally maintaining leakage currents at an acceptable level. On the other hand, a conductive metal-containing non-polysilicon material, such as titanium nitride and the like, may be formed so as to directly connect to the high-k dielectric material, thereby substantially avoiding the presence of a depletion zone. Since the threshold voltage of the transistors is significantly affected by the work function of the gate electrode material that is in contact with the gate dielectric material, an appropriate adjustment of the effective work function with respect to the conductivity type of the transistor under consideration has to be guaranteed, as the well-established way of adjusting the work function by appropriately doping a polysilicon material is no longer available.
For example, appropriate metal-containing gate electrode materials, such as titanium nitride and the like, may frequently be used in combination with appropriate metal species, such as lanthanum, aluminum and the like, to adjust the work function to be appropriate for each type of transistor, i.e., N-channel transistors and P-channel transistors, which may, in some approaches, require an additional band gap offset for the P-channel transistor. For this reason, it has been proposed to appropriately adjust the threshold voltage of some transistor devices by providing a specifically designed semiconductor material at the interface between the gate dielectric material and the channel region of the transistor device, in order to appropriately "adapt" the band gap of the specifically designed semiconductor material to the work function of the metal-containing gate electrode material, thereby obtaining the desired low threshold voltage of the transistor under consideration. Typically, a corresponding specifically designed semiconductor material, such as silicon/germanium and the like, may be provided by an epitaxial growth technique at an early manufacturing stage, which may also present an additional complex process step, which, however, may avoid complex processes for adjusting the work function and thus the threshold voltages in a very advanced process stage.
It turns out, however, that the manufacturing sequence of forming the threshold adjusting semiconductor alloy may have a significant influence on the overall process flow, as will be described in more detail with reference to FIGS. 1a-1f.
FIG. 1a schematically illustrates a cross-sectional view of a semiconductor device 100 that comprises a substrate 101, above which is formed a silicon-based semiconductor material 102 having an appropriate thickness for forming therein and thereabove transistor elements. An isolation structure 102C is formed in the semiconductor layer 102 and laterally delineates and thus forms active regions 102A, 102B. In this context, an active region is to be understood as a semiconductor material in which an appropriate dopant profile is to be created in order to form PN junctions for one or more transistors. In the example shown, the active region 102A corresponds to a P-channel transistor, while the active region 102B corresponds to an N-channel transistor. Hence, the active regions 102A, 102B comprise an appropriate basic dopant concentration in order to determine the basic conductivity of a P-channel transistor and an N-channel transistor, respectively. Furthermore, in the manufacturing stage shown, a mask layer 103 is formed on the active regions 102A, 102B in the form of a silicon dioxide material. Furthermore, an etch mask 104 is provided such that the active region 102B is covered, while the active region 102A, i.e., the mask layer 103 formed thereon, is exposed to an etch ambient 105.
The semiconductor device 100 as illustrated in FIG. 1a may be formed on the basis of the following process strategies. The isolation structure 102C is formed on the basis of well-established lithography, etch, deposition, planarization and anneal techniques, in which, for instance, a trench is formed in the semiconductor layer 102 on the basis of a lithography process, which is subsequently filled with an appropriate insulating material, such as silicon dioxide, silicon nitride and the like. After removing any excess material and planarizing the surface topography, the processing is typically continued by performing a plurality of implantation sequences using an appropriate masking regime in order to introduce the required well dopant species for generating the basic dopant concentration in the active regions 102A, 102B in accordance with requirements of the transistors to be formed. After activating the dopant species and re-crystallizing implantation-induced damage, the processing is continued by forming the mask layer 103 on the basis of, for instance, an oxidation process, followed by the deposition of a mask material, such as a resist material, that is subsequently patterned into the mask 104 by well-established lithography techniques. Next, the etch process 105 is performed, for instance using a wet chemical etch recipe based on hydrofluoric acid (HF), which is a very efficient chemical for removing silicon dioxide material selectively with respect to silicon material.
FIG. 1b schematically illustrates the semiconductor device 100 after the above-described process sequence and after removal of the etch mask 104 (FIG. 1a). The etch process 105 (FIG. 1a) is typically performed in an appropriate chemical reactor in which a plurality of substrates may be concurrently processed, wherein the wet chemical etch chemistry may also be provided at the back side (not shown) of the substrate 101, thereby also efficiently removing any oxide material which may have been formed upon providing the mask material 103. Upon exposure of the active region 102A, the device 100 may be prepared for a subsequent selective epitaxial growth process for forming a silicon/germanium alloy on the active region 102A.
FIG. 1c schematically illustrates the semiconductor device 100 when exposed to a further process ambient 106 upon preparing the device 100 for the selective epitaxial growth process. Typically, the process ambient 106 is established in the deposition reactor by applying elevated temperatures and appropriate reactive gas components in order to remove any further contaminants and oxide residues from the exposed surface areas of the active region 102A, which may still be present in the form of a native oxide and the like. During the process 106, a thickness of the mask layer 103 may be reduced, while nevertheless maintaining a significant portion so as to mask the active region 102B.
FIG. 1d schematically illustrates the semiconductor device 100 during a selective epitaxial growth process 108 in which process parameters are selected such that a significant material deposition is restricted to the exposed active region 102A, while a material deposition on a silicon dioxide surface area, such as the surface of the isolation structure 102C and the mask layer 103, is strongly suppressed. For this purpose, the flow rates, the pressure, the temperature and the like may be selected in accordance with well-established selective epitaxial growth recipes in order to obtain a desired high deposition selectivity with respect to silicon and silicon dioxide surfaces. Thus, during the selective epitaxial growth process 108, a silicon/germanium alloy 109 is selectively formed on the active region 102A, thereby providing a semiconductor material having a different band gap compared to the silicon-based material of the active region 102A. Generally, the material composition of the alloy 109, as well as the thickness thereof, has a strong influence on the finally obtained threshold voltage of the P-channel transistor to be formed in and above the active region 102A. For example, in sophisticated applications, a target thickness of the silicon/germanium alloy 109 is in the range of approximately 8-50 nm, wherein a thickness variation of several percent may result in a significant variability of the finally achieved transistor characteristics. Moreover, since the transistor characteristics may also be strongly influenced by the further processing, for instance by forming a high-k dielectric material in combination with a metal-containing electrode material, in particular when adjusting the critical work function of the resulting electrode material, any process irregularities, such as contamination and the like, may also significantly affect transistor performance and device uniformity.
FIG. 1e schematically illustrates the semiconductor device 100 when exposed to an etch ambient 110 in which the mask 103 (FIG. 1d) is removed selectively with respect to the active region 102B and selectively to the active region 102A, which may now comprise the threshold adjusting semiconductor alloy 109. The etch process may be performed on the basis of hydrofluoric acid, which may be applied in a chemical reactor, as discussed above, thereby efficiently removing silicon oxide-based material from the semiconductor layer 102 and any other exposed surface areas, such as the back side of the substrate 101 and the like.
FIG. 1f schematically illustrates the semiconductor device 100 in a further advanced manufacturing stage. As illustrated, a first gate electrode structure 160A is formed on the active region 102A, i.e., on the threshold adjusting semiconductor alloy 109, and comprises a gate dielectric material 161A in combination with a conductive metal-containing electrode material 162A. Moreover, a further electrode material 163, for instance in the form of a silicon material, may be provided, possibly in combination with a dielectric cap material 164. Similarly, a second gate electrode structure 160B is formed on the active region 102B and comprises a gate dielectric material 161B in combination with a metal-containing electrode material 162B. Furthermore, the gate electrode structure 160B may also comprise the electrode material 163 and the dielectric cap material 164. The gate electrode structures 160A, 160B may have a gate length, i.e., in FIG. 1f, the horizontal extension of the electrode materials 162A, 162B, respectively, which may be 50 nm and less, depending on the overall design requirements. Furthermore, it should be appreciated that the gate dielectric material 161A may basically have the same configuration as the gate dielectric material 161B, while, in some cases, an additional work function adjusting species, such as aluminum, lanthanum and the like, may be incorporated so as to provide the desired electronic characteristics of a transistor 150A or a transistor 150B, respectively. Similarly, the metal-containing electrode materials 162A, 162B may have basically the same configuration in some approaches, for instance these materials may be provided in the form of titanium nitride and the like, while, in other cases, a work function metal species may be incorporated therein so that the materials 162A, 162B may differ in their material composition so as to obtain a different desired work function for the transistors 150A, 150B.
The semiconductor device 100 as shown in FIG. 1f may be formed on the basis of a complex process sequence in which appropriate materials for the gate dielectric material 161A, 161B may be formed, for instance, by oxidation in combination with deposition techniques and the like. For example, a very thin silicon oxide based material may be provided so as to act as an efficient interface material, followed by a high-k dielectric material, such as hafnium oxide and the like. Thereafter, appropriate work function metal species may be deposited and patterned, possibly in combination with any heat treatment for diffusing appropriate species towards and into the dielectric material, thereby forming the gate dielectric layers 161A, 161B having included therein different types of work function species. In other cases, the work function metals may be provided as distinct layers above the gate dielectric materials and may thus represent a portion of the metal-containing electrode materials 162A, 162B. Thereafter, the electrode material 163 may be deposited, for instance, in the form of amorphous silicon and the like, followed by the deposition of the dielectric cap material 164, possibly in combination with other materials, such as hard mask materials, anti-reflective coating (ARC) materials and the like. Next, the complex gate layer stack may then be patterned by applying sophisticated lithography and etch techniques in order to obtain the gate electrode structures 160A, 160B. It should be appreciated that the finally achieved electronic characteristics of the gate electrode structures 160A, 160B may depend on the material composition of the various material and the uniformity of the corresponding deposition, lithography and etch processes.
Thereafter, the processing is continued by forming drain and source regions, which may be preceded by the incorporation of a strain-inducing semiconductor alloy in one or both of the active regions 102A, 102B, if required. The drain and source regions may typically be formed by ion implantation on the basis of an appropriate spacer structure to be formed on sidewalls of the gate electrode structures 160A, 160B. Finally, metal silicide regions may be formed in the drain and source areas and in the electrode material 163, thereby completing a basic transistor configuration using the sophisticated high-k metal gate electrode structures 160A, 160B. It turns out, however, that the resulting transistor elements 150A, 150B may suffer from an increased variability in transistor characteristics, such as threshold variability and the like, which may thus significantly reduce production yield for sophisticated semiconductor devices requiring a high-k metal gate electrode structure.
The present disclosure is directed to various methods that may avoid, or at least reduce, the effects of one or more of the problems identified above.

Reducing contamination in a process flow of forming a channel semiconductor alloy in a semiconductor device


A portable soccer goal with rebounding net to return a ball struck into the net. The frame of the goal is formed by a pair of vertical posts and a long horizontal tube and is secured to the ground by a pair of base supports. Pivotable struts further support the vertical posts. The net has a sleeve that positively joins the net to the frame over the entire horizontal length of the frame, and there is a resilient mainstay cord threaded into the net near the periphery. The net and mainstay cord are secured by hooks at the base supports, and the net is oriented to the outside of the struts. When the struts are spread outwards, the tension in the net is increased so as to be sufficient to rebound a ball struck into the net.

A soccer goal is a rectangle into which a soccer ball is kicked in order to score in the game of soccer. A typical goal is framed by two vertical posts joined by a horizontal top post and enclosed by a net attached to the posts and drawn back behind them so as to contain any ball struck into the goal. Such soccer goals are well known and are in common use for regulation games and practice exercises.
There are, however, several problems associated with using a regulation soccer goal for certain applications. Such applications that raise problems for a traditional soccer goal include short field soccer games, practice exercises, and the need for portable or removable soccer goals in fields designed for multiple use.
In order to conserve space, a "short field" version of soccer has emerged for recreational and club play. Using a short field, fewer players and sometimes no goalie, a 3-person team ("3v3") or a 4-person, 5, 6, 7, 8 or other "short-handed" teams may be fielded.
Because space in the short field game is at a premium and, when played without a goalie, there is no need for a goalie to stand within the goal, it would be desirable to foreshorten the area within the goal enclosed by the net. Because the players in the short field game are running at full speed in a relatively small area, it would be desirable to have a goal that is strong, stable, but also safe--among the safety concerns would be the elimination of sharp edges and protruding objects such as bolts, nuts and other fasteners.
Practice exercises and drills for soccer include many versions of taking a shot on goal. A hard, accurate kick with an eye towards taking a follow-up shot if an initial shot is deflected, rebounded or blocked out of the goal is desirable. To maximize the efficiency of practice drills, it would be desirable for a player to be able to strike a ball into a soccer goal that simulates a traditional soccer goal but which will rebound the ball so that a player may take a series of rapid fire shots on goal, and/or take a power shot on goal and immediately follow through with a rebounding shot after the first shot is deflected back out of goal. Such practice objectives will also be served by a compact goal so that several such goals may be setup within the limited space of a practice field.
Finally, although there remain fields dedicated to playing soccer in which heavy, semi-permanently installed traditional soccer goals may be affixed, many soccer games are played in less permanent surroundings. Where space is at a premium, a practice soccer goal, a short field game soccer goal, or even a very large number of weekend tournament or club sport goals must be moved, positioned, setup, used and then disassembled and removed with relative ease. It would be desirable, therefore, to have a stable soccer goal that is also light weight, portable and relatively easy to setup and remove. Likewise, because soccer is practiced everywhere, but because an empty field, street, driveway or even a solid wall afford little in the way of practicing a kick on goal, a stable and portable soccer goal would be desirable.
To summarize, it would be highly desirable in short field soccer, practice exercises, and soccer played in multiple use areas to have a soccer goal that is safe, stable, light weight, portable, easy to setup and remove, and that also returns the ball to the kicker after the ball is struck into the net.
Examples of previous work done in providing a soccer practice goal, or a portable training goal are described in U.S. Pat. Nos. 4,083,561 of Daffer for a soccer practice net; 4,116,446 of Thompson for a game net support apparatus; 4,127,272 of Pennell for a portable soccer goal; 4,258,923 of Senoh for a football goal structure; 4,407,507 of Caruso for a portable soccer goal; 5,048,844 of Haseltine for a portable rebounding soccer training goal; and 5,080,375 of Moosavi for an adjustable soccer goal.
None of the prior art of which the applicant is aware fully solves the problem of providing a safe, stable, light weight, portable, easy to setup and remove soccer goal that also returns the ball to the kicker after the ball is struck into the net. It is the object of this invention to answer those needs.

Rebounding portable soccer goal and method of use


A voltage regulator having a MOS transistor driver includes a p-channel MOS transistor at a voltage input terminal Vin and a p-channel MOS transistor at a voltage output terminal Vout. A drain of the input side p-channel MOS transistor is connected to the voltage input terminal Vin. A threshold voltage or a voltage lower than the threshold voltage is applied to a gate of the input side p-channel MOS transistor. A drain of the output side p-channel MOS transistor is connected to the voltage output terminal Vout. A current flowing through the input side p-channel MOS transistor drives a voltage regulator circuit and the output side p-channel MOS transistor.

1. Field of the Invention
The present invention generally relates to a voltage regulator, and specifically relates to CMOS voltage regulators used in vehicles or industrial machines and CMOS voltage regulators connected to batteries.
2. Description of the Related Art
Parasitic PN junctions are undesirably generated between a source and a well, and a drain and the well of an n-channel MOS transistor as shown in FIG. 4. Therefore, two diodes D1 and D2 are formed in the MOS transistor. In the n-channel transistor shown in FIG. 4, the p-well is connected to ground.
There is no problem when a drain voltage is higher than a well voltage. When the drain voltage is lower than the well voltage by −0.7 V or more, the PN diode D2 turns on and a large forward current flows through the diode D2.
Similarly, in a p-channel MOS transistor, when a drain voltage is higher than a well voltage by 0.7 V or more, a PN diode turns on and a large forward current flows through the diode.
In general, a well of a MOS transistor is formed on a P substrate as shown in FIG. 6. In the p-channel MOS transistor having a normal PNP junction shown in FIG. 6, a parasitic vertical PNP bipolar transistor formed by a source (p+), a well (n) and the substrate (p) is generated inside. When input side current driving power becomes lower than the output side current driving power, a current does not flow through the normal PNP junction MOS transistor, but the parasitic vertical PNP bipolar transistor turns on, through which a current I0 undesirably flows.
A scheme for inhibiting such a reverse current from an output terminal to an input terminal is proposed in a DC power supply circuit disclosed in Japanese Publication H7-69749. In the DC power supply circuit, a back gate voltage of a power MOS transistor is changed to a voltage that turns off a parasitic diode generated between a source and a drain of the power MOS transistor, in order to inhibit the reverse current from the output terminal to the input terminal.
The DC power supply circuit includes a back gate control circuit for controlling the back gate voltage so as to turn off the parasitic diode. The back gate control circuit comprises two stage inverters formed by p-channel MOS transistors and n-channel MOS transistors. The drains of the post stage p-channel and n-channel MOS transistors are connected together, and the connecting node is connected to the back gate of the power MOS transistor.
FIG. 5 is a circuit diagram of a conventional voltage regulator circuit.
In recent years and continuing, in voltage regulator products, low dropout products formed by CMOS transistors are remarkably popular because of their low current consumption. In such products, a p-channel transistor M30 is used as an output control transistor. When an input voltage Vin becomes lower than GND voltage by −0.7 V or more in a case of power shut down, for example, PN diodes formed between drains and wells in MOS transistors included in a reference voltage circuit 51 (providing a reference voltage VREF) and an operational amplifying circuit 21 are forwardly biased, and accordingly a large current flows from GND to the input Vin. This phenomenon may cause equipment malfunction or breakdown.
In order to avoid such a problem, it is generally regulated so that a voltage lower than −0.3 V is not applied to an input of the CMOS voltage regulator.
A CMOS voltage regulator has a problem in that when its output voltage becomes higher than its input voltage, a PN junction between a drain and a well in an output controlling p-channel MOS transistor is forwardly biased and a large current flows from an output terminal to an input terminal.
This phenomenon also may cause equipment malfunction or breakdown.
On the other hand, bipolar transistors with an opened base do not allow current to flow unless a considerably large voltage is applied between a collector and emitter.
Therefore, some bipolar voltage regulators have no problem even if a large reverse voltage is applied to an input. However, a forward diode has to be inserted at an input terminal, and accordingly a voltage higher than a forward voltage (a threshold voltage) has to be applied to the input terminal and low dropout products cannot be provided.
As explained above, in conventional voltage regulators having a MOS transistor, when a reverse voltage is applied to an input terminal, a forward current flows between a drain and a well in a p-channel MOS transistor, and therefore a large current flows from an output terminal to the input terminal, causing equipment malfunction and breakdown.
In a case where current driving power of an input terminal side p-channel MOS transistor is lower than the current driving power of an output terminal side p-channel MOS transistor, a parasitic diode formed by a drain and an n-well of the input terminal p-channel MOS diode turns on, or a parasitic vertical PNP bipolar transistor formed by a p-source, the n-well and a p-substrate turns on, causing equipment malfunction or breakdown.

This patent is subject to a terminal disclaimer.


The present disclosure relates to a process for making a seamless tube from a liquid. A mandrel may be provided having a longitudinal axis, an outer surface and a length. A liquid material may be applied to the outer surface of the mandrel by one or more doctor blades, spaced apart from the mandrel outer surface and inclined at an angle α with respect to the mandrel longitudinal axis, which may be moved along the longitudinal axis of the mandrel while rotating the mandrel around its longitudinal axis. One or a plurality of fingers may overly the mandrel and be positioned upstream of the one or more of blades, relative to the direction of movement of the blades along the longitudinal axis of the mandrel. The liquid material may then be converted to form a seamless tube.

1. Field of the Invention
The present disclosure relates to the manufacture of seamless tubes formed from liquids material. In particular, the process may employ one or more doctor blades and associated fingers to apply a coating of the liquid material to the mandrel surface.
2. Description of Related Art
Various methods of coating liquid-like materials onto substrates are well known. These processes may include vertical dip or ring coating; spray coating; and injection molding. These methods may suffer from several disadvantages. Dip or ring coating may require that a large amount of coating solution be generated to coat the part. The part may be submerged into a vat of material and slowly removed. Therefore, excess material may be required and the yield may be quite low. Spray coating also may tend to have a low yield due to the material lost in the overspray. In addition, both dip/ring coating and spray coating may be limited in the material viscosity that can be successfully applied. Spray coating may require a relatively low viscosity in order for the material to be atomized in the spray gun. Dip/ring coating may require higher viscosities to prevent sag of the coating. Methods such as injection molding require sophisticated molds, high pressures and relatively high material viscosities to successfully produce a part.


A suction cup removably attached to a housing lifts and moves an object. A venturi removably attached to the housing provides a vacuum effect to secure the suction cup to the object. The venturi includes a pair of opposing ears. When the venturi is inserted into a venturi hole of the housing, the ears compress a pin. When the venturi is rotated to an attached position, the ears do not contact the pin, and a spring biases the pin outwardly to secure the venturi to the housing. The pin is coupled to a button on the housing that can be slid to move the pin inwardly to allow rotation and removal of venturi.

The present invention relates generally to a suction cup assembly including a housing having a venturi removably connected to the housing in a quick connect attachment and a suction cup to lift and move an object.
Suction cups are commonly employed to lift and moves objects in an industrial application. Suction cups include a substantially conical body and are usually formed of a resilient material, such as plastic or rubber. When the body of the suction cup is placed against the object, a vacuum source expels air within a cavity formed by the conical body. As the air is expelled, the suction cup forms a tight seal on the object, allowing the object to be lifted and moved. The suction cup is usually mounted to a housing including a clamping stem. A robot arm of a tooling machine attached to the clamping stem moves the suction cup and the attached object.
A suction cup occasionally needs to be replaced due to breakage, wear, or because a suction cup of a different shape or size is needed. Therefore, it is desirable that the suction cup is able to be changed quickly and easily.
A venturi is commonly employed to provide the vacuum source that attaches the suction cup to the object. In one prior art suction cup assembly, the venturi is secured to the housing by a pair of bolts. Another prior art venturi is integrated in the housing. However, the venturi is internal, and it cannot be easily removed from the housing when cleaning is necessary. Additionally, in the prior art, the exhaust hole of the venturi is large, requiring a shuttle valve to block air expulsion from the exhaust hole.
Hence, there is a need in the art for a suction cup assembly including a venturi that is removably connected to a housing.

Suction cup assembly including a quick release venturi


A method for operating a computer storage system is disclosed. One or more data storage devices are configured to store a data content of a data container. A data structure having a plurality of permitted modification times (mtimes) is generated, the mtimes to control modifying a data stored in the data container. An I/O operation is performed by the storage system in response to a selected mtime. A request for the I/O operation is received from a client, and the data structure having a plurality of permitted modification times (mtimes) is generated in response to the request. The selected mtime is transmitted to the client, and an I/O operation is requested by the client in response to the selected mtime. The I/O operation is performed as an atomic I/O operation.

A storage system typically comprises one or more storage devices into which information may be entered, and from which information may be obtained, as desired. The storage system includes a storage operating system that functionally organizes the system by, inter alia, invoking storage operations in support of a storage service implemented by the system. The storage system may be implemented in accordance with a variety of storage architectures including, but not limited to, a network-attached storage environment, a storage area network and a disk assembly directly attached to a client or host computer. The storage devices are typically disk drives organized as a disk array, wherein the term "disk" commonly describes a self-contained rotating magnetic media storage device. The term disk in this context is synonymous with hard disk drive (HDD) or direct access storage device (DASD).
The storage operating system of the storage system may implement a high-level module, such as a file system, to logically organize the information stored on volumes as a hierarchical structure of data containers, such as files and logical units. For example, each "on-disk" file may be implemented as set of data structures, i.e., disk blocks, configured to store information, such as the actual data for the file. These data blocks are organized within a volume block number (vbn) space that is maintained by the file system. The file system may also assign each data block in the file a corresponding "file offset" or file block number (fbn). The file system typically assigns sequences of fbns on a per-file basis, whereas vbns are assigned over a larger volume address space. The file system organizes the data blocks within the vbn space as a "logical volume"; each logical volume may be, although is not necessarily, associated with its own file system.
A known type of file system is a write-anywhere file system that does not over-write data on disks. If a data block is retrieved (read) from disk into a memory of the storage system and "dirtied" (i.e., updated or modified) with new data, the data block is thereafter stored (written) to a new location on disk to optimize write performance. A write-anywhere file system may initially assume an optimal layout such that the data is substantially contiguously arranged on disks. The optimal disk layout results in efficient access operations, particularly for sequential read operations, directed to the disks. An example of a write-anywhere file system that is configured to operate on a storage system is the Write Anywhere File Layout (WAFL®) file system available from Network Appliance, Inc., Sunnyvale, Calif.
The storage system may be further configured to operate according to a client/server model of information delivery to thereby allow many clients to access data containers stored on the system. In this model, the client may comprise an application, such as a database application, executing on a computer that "connects" to the storage system over a computer network, such as a point-to-point link, shared local area network (LAN), wide area network (WAN), or virtual private network (VPN) implemented over a public network such as the Internet. Each client may request the services of the storage system by issuing file-based and block-based protocol messages (in the form of packets) to the system over the network.
A plurality of storage systems may be interconnected to provide a storage system environment configured to service many clients. Each storage system may be configured to service one or more volumes, wherein each volume stores one or more data containers. Yet often a large number of data access requests issued by the clients may be directed to a small number of data containers serviced by a particular storage system of the environment. A solution to such a problem is to distribute the volumes serviced by the particular storage system among all of the storage systems of the environment. This, in turn, distributes the data access requests, along with the processing resources needed to service such requests, among all of the storage systems, thereby reducing the individual processing load on each storage system. However, a noted disadvantage arises when only a single data container, such as a file, is heavily accessed by clients of the storage system environment. As a result, the storage system attempting to service the requests directed to that file may exceed its processing resources and become overburdened, with a concomitant degradation of speed and performance.
One technique for overcoming the disadvantages of having a single file that is heavily utilized is to stripe the file across a plurality of volumes configured as a striped volume set (SVS), where each volume, such as a data volume (DV), is serviced by a different storage system, thereby distributing the load for the single file among a plurality of storage systems. A technique for data container (such as a file) striping is described in the above-referenced U.S. Patent Publication No. US 2005/0192932, entitled STORAGE SYSTEM ARCHITECTURE FOR STRIPING DATA CONTAINER CONTENT ACROSS VOLUMES OF A CLUSTER. According to the data container striping arrangement, each storage system of may service access requests (i.e., file operations) from clients directed to the same file. File operations, such as read and write operations, are forwarded directly to the storage systems that are responsible for their portions of the data for that file.
In addition to the file data, there are meta-data, such as timestamps and length, associated with the file. A timestamp is a file attribute that provides an indication of the last time the file was modified, i.e., the modification time (mtime) for the file. The mtime is typically consulted on every operation directed to the file and, in the case of a write operation, is changed. For example, in response to a read operation issued by a client, the storage system returns the data and the current mtime on the file, whereas in response to a write operation, the storage system returns an incremented mtime. Effectively, every successive write operation is accorded a greater mtime than the one before it.
Many client protocols, such as the Network File System (NFS) protocol, allow use of client-side "caching" of data retrieved from a storage system. In response to a read operation issued by a client for a file, the storage system returns the requested data along with the current mtime of the file. The client stores the information in a cache memory so that future read operations directed to that file data may be serviced locally at the client (from the cache) instead of remotely over the network. For client-side caching to operate properly, there must be guarantees that the data subsequently retrieved from the cache is consistent with the actual file system and not "stale", i.e., that the file data has not changed since it was cached at the client. To that end, the NFS protocol enables periodic "pinging" (polling) of the state of the file by the client through requests for the current mtime of the file from the storage system If the mtime has not increased since the data was cached, the client-side cache is maintained "fresh" and the client continues to use the cached data. If the mtime has changed, then the client discards its cached data and reissues a read operation to the storage system for file data.
Note that, as used herein, file operations are "serializable" if they can be replayed in a reported order and the result is identical to the actual file system. File operations are "causally connected" if they affect the same meta-data or the same region of the same file. Some client protocols (like NFSv2) require "strong serialization semantics"; that is, mtimes must always increase for operations that complete with increasing wall-clock time, even if they are not casually connected. "Weak serialization semantics", on the other hand, only require that mtimes always increase for operation that complete with increasing wall-clock time if the operations are causally connected.
Certain file system protocols, such as the Common Internet File System (CIFS) protocol, support weak serialization semantics because of the nature of soft locks, such as opportunistic locks (op-locks). An op-lock is an automatically revocable soft lock that allows a client to operate on a range of file data until such time as a server (e.g., the storage system) instructs the client to stop. That is, the client can cache the data and perform read and write operations on the cached data until the storage system instructs it to return is that data to the system. The client can cache the results of write operations since it knows that no other access is allowed to that same region of the file as long as it has an op-lock on the region. As soon as a second client attempts a conflicting operation on that region of the file, the storage system blocks the conflicting operation and revokes the op-lock. In particular, the storage system instructs the client to return ("flush") any write modifications to the system and then discard the entire content of its client-side cache. Once that happens, the storage system unblocks the second client and grants it an op-lock to the conflicting region.
NFSv2 and NFSv3 protocols do not utilize op-locks and, thus, do not employ the above revocation system. For these protocols, the storage system must rely on strong serialization semantics. Other protocols, such as the NFSv4 protocol, use a type of soft lock called delegations that allows the storage system to use weak serialization semantics. Because CIFS and NFSv4 clients rely on such a "rough" protocol for guaranteeing consistency of cached data, they are not concerned with mtimes associated with read and write operations. This, in turn, enables the storage system to service such operation requests with weak serialization semantics.
In the data container striping arrangement described above, there is one volume, i.e., the container attribute volume (CAV), which is responsible for all the timestamps of a particular file stored on the SVS. As a result, for each file operation, the DV accesses the CAV to determine the mtime for the file. In response, the CAV updates the mtime on disk and returns the updated mtime to the DV which, in turn, returns the mtime and any associated data to the client. This arrangement places a substantial load on the storage system serving the CAV with a concomitant decrease in system performance. Moreover, depending on the load of the SVS, the meta-data requests to/from the CAV may become a bottleneck that adversely impacts performance of the system by, e.g., causing certain storage systems to stall (wait) until their meta-data requests have been processed before servicing client data access requests.

System and method for efficiently guaranteeing data consistency to clients of a storage system cluster


A new cultivar of Peperomia plant named ‘EC-PEPE-2007’ that is characterized by leaves that are grey-green on the upper surface with dark grey veins, leaves that are bright red on the lower surface and a rosette like plant habit.

The present invention relates to a new and distinct cultivar of Peperomia plant botanically known as Peperomia caperata and hereinafter referred to by the cultivar name 'EC-PEPE-2007'.
'EC-PEPE-2007' originated from the crossing of the female or seed parent, a proprietary Peperomia caperata cultivar identified as '15OB-87' (not patented) and the male or pollen parent, a proprietary Peperomia caperata cultivar identified as '15OB-78' (not patented). The crossing was conducted in 2017 in Sappemeer, Netherlands. The resulting seeds were subsequently planted and grown. The cultivar 'EC-PEPE-2007' was selected by the inventor in 2018 in a controlled environment as a single plant within the progeny of the stated cross in a cultivated area of Sappemeer, Netherlands.
Asexual reproduction of the new cultivar 'EC-PEPE-2007' first occurred by leaf cuttings in 2018 in Sappemeer, Netherlands. Since that time, under careful observation, the unique characteristics of the new cultivar have been uniform, stable and reproduced true to type in successive generations of asexual reproduction.