Technology Used in Ceramic PCBs Production
Ceramic substrate refers to a special process board where copper foil is directly bonded to the surface (single side or double side) of alumina (Al2O3) or aluminum nitride (AlN) ceramic substrate at high temperature. The produced ultra-thin composite substrate has excellent electrical insulation properties, high thermal conductivity, excellent solderability and high adhesion strength, and can etch various patterns like a PCB board, with a large current carrying capacity ability. Therefore, the ceramic substrate has become the basic material of high-power power electronic circuit structure technology and interconnection technology. It is widely used in many fields. So, in what fields are ceramic PCBs specifically used?
- High-power power semiconductor module, semiconductor refrigerator, electronic heater, power control circuit, power mixing circuit.
- Intelligent power components, high frequency switching power supply, solid state relay.
- Automotive electronics, and military electronic components.
- Solar panel components, special telecommunications exchanges, receiving systems, lasers and other industrial electronics.
Advantages and disadvantages of ceramic PCBs
- The first is the material, the traditional PCB substrate is mostly epoxy plastic. Due to its relatively good economy, it still occupies a dominant position in the entire electronic market so far. However, many special fields such as high temperature, corrosive environment, and high vibration frequency are not suitable.
- Ceramic materials are very suitable for use in electronic fields due to their advantages of high thermal conductivity, good chemical stability, high thermal stability and high melting point.
- Good thermal cycling performance, with 50,000 cycles and high reliability.
- Like PCB board (or IMS substrate), various patterns can be etched; no pollution and no pollution.
- The use temperature is wide -55℃～850℃. The coefficient of thermal expansion is close to silicon, simplifying the production process of the power module.
- The advantages of ceramic circuit boards also retain the characteristics of their materials, and unlike traditional PCBs need to use an insulating medium as an insulating layer. The ceramic itself is an insulating layer. At the same time, it also has a high frequency and a low dielectric constant, because its manufacturing process is easier in light, thin, and miniaturized.
- Raw materials are more expensive than traditional PCBs, and the cost is higher.
- The manufacturing area is small, and it is difficult to produce on a large area. High-end products are often used, and low-end products are not used.
- The processing difficulty is also relatively large because of the high hardness and density.
- It is easier to break during processing. In addition, because of the low toughness and brittleness of ceramic materials, the scrap rate in each process is relatively high.
- The final surface metallization is also a high cost of early equipment.
However, as an emerging product, ceramic PCBs are very suitable for the development of this intelligent era, and its shortcomings are constantly improving. A batch of new ceramic materials such as alumina ceramics were manufactured. This increases its toughness and reduces brittleness. At the same time, production technology is constantly improving, reducing costs.
- Drilling: Mechanical drilling holes are used to form connecting pipes between metal layers.
- Plated-through hole: After drilling the copper wire between the connecting layers, the circuit between the layers is not opened. Therefore, a conductive layer must be formed on the hole wall to connect the wires. This process is commonly referred to as “PTH” in industry. The technological process mainly includes 3 procedures: Desmear, chemical copper and electroplated copper.
- Dry film pressing: making photosensitive etched photosensitive layer.
- Layer image transfer: Use exposure to transfer the film image to the surface of the circuit board.
- Outer layer exposure: After the photosensitive film is attached, the circuit board is similar to the inner layer of the production process, exposed again and developed. The main function of this photographic film is to determine the area that needs to be electroplated. Electroplating is not required. The area we cover is the area that does not require electroplating.
- Magnetron sputtering: The energy and momentum between the positive ions generated and the atoms on the surface of the target during the gas glow discharge process. They will be exchanged and used to move the material from the source material to the substrate for thin film deposition.
- Etching-The formation of external lines: A technique that uses chemical reactions or physical impact to remove material. The function of etching is reflected in the selective removal of specific patterns.
- Solder-proof coating: The purpose of the ceramic circuit board is to carry electronic components and achieve the purpose of connection. Therefore, after completing the circuit of the circuit board, the area where the electronic components are assembled must be defined. And polymer materials should be used to properly protect non-assembled areas. Due to the assembly and soldering of electronic components, the polymer material that partially protects the circuit board is called “solder paint”. Most current photosensitive solder resists are wet ink coatings.
After the circuit is completed, the circuit board will be fed into the stripping and etching. The main job is to completely strip the plating resist and expose the copper to be etched to the etching solution. Since the top of the wiring area is already protected by tin, an alkaline etching solution is used to etch copper. However, since the wiring has been protected by tin, the wiring of the wiring area can be maintained, so that the wiring of the wiring area provides the entire wiring board.
"Kutengenezwa kwa PCB za kauri ni ""bodi maalum ya mchakato ambapo karatasi ya shaba imeunganishwa moja kwa moja kwenye uso (upande mmoja au upande mbili) wa alumina (Al2O3) au nitridi ya alumini (AlN) substrate ya kauri kwa joto la juu." Substrate ya mchanganyiko nyembamba sana ina sifa bora za insulation ya umeme, conductivity ya joto ya juu, solderability bora na nguvu ya kushikamana ya juu, na inaweza kuchora mifumo mbalimbali kama bodi ya PCB, na uwezo mkubwa wa kubeba sasa. Kwa hiyo, substrate ya kauri imekuwa nyenzo ya msingi ya teknolojia ya muundo wa mzunguko wa umeme wa nguvu na teknolojia ya muunganisho. Inatumiwa sana katika nyanja nyingi. Kwa nini PCB za kauri zinatumiwa? - High-nguvu nguvu semiconductor moduli, semiconductor friji, elektroniki heater, nguvu kudhibiti mzunguko, nguvu kuchanganya mzunguko. - Intelligent nguvu vipengele, high frequency kubadili umeme, hali ya imara relay. - Elektroniki ya magari, na vipengele vya elektroniki vya kijeshi. - Sehemu za jopo la jua, kubadilishana maalum za mawasiliano ya simu, mifumo ya kupokea, lasers na vifaa vingine vya elektroniki vya viwanda. Faida na hasara za PCB za kauri - Kwanza ni nyenzo, substrate ya jadi ya PCB ni plastiki ya epoxy. Kwa sababu ya uchumi wake mzuri, bado inashikilia nafasi ya kutawala katika soko lote la elektroniki hadi sasa. Hata hivyo, maeneo mengi maalum kama vile joto la juu, mazingira corrosive, na frequency ya juu ya vibration si yanafaa. Vifaa vya kauri ni bora kwa ajili ya matumizi katika uwanja wa umeme kutokana na faida zao za conductivity ya juu ya joto, utulivu mzuri wa kemikali, utulivu wa juu wa joto na kiwango cha juu cha kuyeyuka. - Utendaji mzuri wa mzunguko wa joto, na mizunguko 50,000 na kuegemea kwa juu. PCB (au IMS substrate) - Picha za PCB zinaweza kuchorwa kwa njia ya kuchora, na inaweza kuonekana kama ya kawaida. - Joto la matumizi ni pana -55 ° C < 850 ° C. coefficient ya upanuzi wa joto ni karibu na silicon, kurahisisha mchakato wa uzalishaji wa moduli nguvu. Bodi za mzunguko wa kauri pia huhifadhi sifa za vifaa vyao, na tofauti na PCB za jadi zinahitaji kutumia njia ya kutenganisha kama tabaka la kutenganisha. Chumba hicho cha kauri ni tabaka la kutenganisha. Wakati huo huo, pia ina mzunguko wa juu na dielectric mara kwa mara ya chini, kwa sababu mchakato wake wa utengenezaji ni rahisi katika mwanga, nyembamba, na miniaturized. Vifaa vya msingi ni ghali kuliko PCB za jadi, na gharama ni ya juu. - Eneo la utengenezaji ni ndogo, na ni vigumu kuzalisha kwenye eneo kubwa. Bidhaa za hali ya juu hutumiwa mara nyingi, na bidhaa za hali ya chini hazitumiwi. - Ugumu wa usindikaji pia ni kiasi kikubwa kwa sababu ya ugumu wa juu na wiani. - Ni rahisi kuvunjika wakati wa usindikaji. Kwa kuongezea, kwa sababu ya ugumu mdogo na brittleness ya vifaa vya kauri, kiwango cha taka katika kila mchakato ni cha juu. - Metallization mwisho uso pia ni gharama kubwa ya vifaa vya mapema. Hata hivyo, kama bidhaa mpya, PCBs ya kauri ni sahihi sana kwa maendeleo ya enzi hii ya akili, na mapungufu yake ni daima kuboresha. Kundi la vifaa vipya vya kauri kama vile kauri za alumina zilitengenezwa. Hilo huongeza nguvu zake na kupunguza udhaifu wake. Wakati huohuo, teknolojia ya uzalishaji inaboresha daima, ikipunguza gharama. - Drilling: Mechanical drilling mashimo ni kutumika kuunda kuunganisha mabomba kati ya tabaka chuma. - Plated-kupitia shimo: Baada ya kuchimba waya shaba kati ya tabaka kuunganisha, mzunguko kati ya tabaka si kufunguliwa. Kwa hiyo, tabaka conductive lazima kuundwa juu ya ukuta shimo kuunganisha waya. Utaratibu huu ni kawaida inajulikana kama <unk>PTH<unk> katika sekta. Mchakato wa kiteknolojia hasa inajumuisha taratibu tatu: Desmear, shaba ya kemikali na shaba ya electroplated. - Dry filamu kushinikiza: kufanya photosensitive etched photosensitive safu. - Layer picha uhamisho: Kutumia mfiduo kuhamisha filamu picha kwa uso wa bodi ya mzunguko. - Exposition tabaka nje: Baada ya filamu photosensitive ni amefungwa, mzunguko bodi ni sawa na tabaka la ndani ya mchakato wa uzalishaji, wazi tena na maendeleo. Kazi kuu ya filamu hii ya picha ni kuamua eneo ambalo linahitaji kuwa electroplated. Electroplating haihitajiki. Eneo tunalofunika ni eneo ambalo halihitaji electroplating. - Magnetron sputtering: Nishati na kasi kati ya ions chanya zinazozalishwa na atomu juu ya uso wa lengo wakati wa mchakato wa kutolewa kwa mwangaza wa gesi. Wao itakuwa kubadilishana na kutumika kuhamisha nyenzo kutoka nyenzo chanzo kwa substrate kwa ajili ya filamu nyembamba depositions. - Etching-Uundaji wa mistari ya nje: Mbinu ambayo hutumia athari za kemikali au athari ya kimwili kuondoa nyenzo. Kazi ya kuchora huonyeshwa katika kuondolewa kwa njia ya kuchagua kwa michoro fulani. - Solder-uthibitisho mipako: kusudi la kauri mzunguko bodi ni kubeba vipengele vya elektroniki na kufikia kusudi la uhusiano. Kwa hiyo, baada ya kukamilisha mzunguko wa bodi ya mzunguko, eneo ambapo vipengele vya elektroniki ni wamekusanyika lazima kufafanuliwa. Na vifaa vya polima vinapaswa kutumiwa kulinda vizuri maeneo yasiyounganishwa. Kutokana na mkusanyiko na soldering ya vipengele vya elektroniki, nyenzo ya polima ambayo kwa sehemu inalinda bodi ya mzunguko inaitwa <unk> solder rangi <unk>. Wengi wa sasa photosensitive solder inashindana ni mvua wino mipako. Baada ya mzunguko ni kukamilika, bodi mzunguko itakuwa kulishwa katika stripping na etching. Kazi kuu ni kabisa kuondoa plating kukabiliana na kufunua shaba kuwa etched kwa ufumbuzi etching. Kwa kuwa sehemu ya juu ya eneo la waya tayari inalindwa na bati, suluhisho la kuchoma la alkali hutumiwa kuchoma shaba. Hata hivyo, kama wiring imekuwa kulindwa na bati, wiring ya eneo wiring inaweza kudumishwa, hivyo kwamba wiring ya eneo wiring hutoa bodi nzima wiring.