Njengoba sonke sazi, izakhiwo eziyisisekelo ze PCB (ibhodi lesifunda eliphrintiwe) lincike ekusebenzeni kwe-substrate impahla yayo. Ngakho-ke, ukuze kuthuthukiswe ukusebenza kwebhodi lesifunda, ukusebenza kwe-substrate impahla kufanele kuqala kuthuthukiswe. Kuze kube manje, izinto ezintsha ezihlukahlukene ziyathuthukiswa futhi zisetshenziselwa ukuhlangabezana nezidingo zobuchwepheshe obusha kanye nezimakethe zemakethe.

Eminyakeni yamuva, amabhodi esifunda anyathelisiwe abe noshintsho. Imakethe isuke ikakhulukazi emikhiqizweni yezingxenyekazi zekhompuyutha ezijwayelekile njengamakhompyutha edeskithophu yaya kwezokuxhumana okungenantambo njengamaseva namatheminali eselula. Imishini yokuxhumana ephathwayo emelwe omakhalekhukhwini be-smart phone ikhuthaze ukuthuthukiswa kwama-PCB anomthamo omkhulu, isisindo esilula kanye nama-PCB asebenza ngezindlela eziningi. Uma ingekho impahla engaphansi, futhi izidingo zayo zenqubo zihlobene eduze nokusebenza kwe-PCB, ubuchwepheshe besekethe obuphrintiwe ngeke bufezeke. Ngakho-ke, ukukhethwa kwe-substrate material kudlala indima ebalulekile ekuhlinzekeni ikhwalithi nokuthembeka kwe-PCB kanye nomkhiqizo wokugcina.

Hlangana nezidingo zokuminyana okuphezulu nemigqa emihle

•Izimfuneko zefoyili yethusi

Wonke amabhodi e-PCB aqhubekela ekuminyaneni okuphezulu namasekhethi angcono kakhulu, ikakhulukazi i-HDI PCB (High Density Interconnect PCB). Eminyakeni eyishumi edlule, i-HDI PCB yayichazwa ngokuthi i-PCB, futhi ububanzi bayo bomugqa (L) nesikhala somugqa (S) kwakungu-0.1mm noma ngaphansi. Kodwa-ke, amanani amanje ajwayelekile we-L no-S embonini ye-elekthronikhi angaba mancane njengo-60 μm, futhi ezimweni ezithuthukile, amanani awo angaba ngaphansi kuka-40 μm.

Unganquma kanjani i-PCB substrate material yakho

Indlela yendabuko yokwakheka komdwebo wesifunda isenqubo yokuthwebula nokunamathisela. Ngokusetshenziswa kwe-substrates ye-foil yethusi emincane (enogqinsi ebangeni lika-9μm kuya ku-12μm), inani eliphansi lika-L no-S lifinyelela ku-30μm.

Ngenxa yezindleko eziphezulu zefoyili yethusi elincanyana i-CCL (i-Copper Clad Laminate) kanye nokukhubazeka okuningi esitakini, abakhiqizi abaningi be-PCB bavame ukusebenzisa indlela ye-etching-copper foil, futhi ukujiya kwe-foil yethusi kusethelwe ku-18μm. Eqinisweni, le ndlela ayinconywa ngoba iqukethe izinqubo eziningi kakhulu, ukushuba kunzima ukulawula futhi kuholela ezindlekweni eziphakeme. Ngenxa yalokho, i-foil yethusi encane ingcono. Ngaphezu kwalokho, lapho amanani ebhodi we-L no-S engaphansi kuka-20μm, i-foil yethusi evamile ayisebenzi. Okokugcina, kunconywa ukusebenzisa i-ultra-thin copper foil, ngoba ukushuba kwayo kwethusi kungalungiswa ebangeni le-3μm kuya ku-5μm.

Ngaphezu kobukhulu be-foil yethusi, ama-circuits amanje anembayo nawo adinga ingaphezulu le-copper eline-roughness ephansi. Ukuze kuthuthukiswe ikhono lokubopha phakathi kwe-foil yethusi kanye ne-substrate impahla futhi uqinisekise amandla e-peel we-conductor, ukucubungula okungalungile kwenziwa endizeni ye-foil yethusi, futhi ukuhlukumeza okuvamile kwe-foil yethusi kukhulu kuno-5μm.

Ukushumeka ucwecwe lwethusi lwe-hump njengoba into eyisisekelo ihlose ukuthuthukisa amandla ayo ekhasi. Kodwa-ke, ukuze kulawulwe ukunemba komthofu kude nokweqisa ngesikhathi sokufakwa kwesifunda, kuvame ukubangela ukungcola kwe-hump, okungase kubangele ukujikeleza okufushane phakathi kwemigqa noma ukuncipha komthamo wokufakwa, okuthinta ikakhulukazi amasekhethi amahle. Ngakho-ke, i-foil yethusi enobunzima obuphansi (ngaphansi kuka-3 μm noma ngisho no-1.5 μm) iyadingeka.

Nakuba ukuqina kwe-foil yethusi kuncishisiwe, kusadingeka ukugcina amandla e-peel omqhubi, okubangela ukwelashwa okukhethekile ebusweni be-foil yethusi kanye ne-substrate material, okusiza ukuqinisekisa amandla e-peel umqhubi.

• Izidingo zokufaka ama-laminates e-dielectric

Esinye sezici zobuchwepheshe eziyinhloko ze-HDI PCB ilele enqubweni yokwakha. I-RCC evame ukusetshenziswa (i-resin coated copper) noma i-prepreg epoxy glass cloth kanye ne-copper foil lamination ayivamisile ukuholela kumasekhethi amahle. Manje sekuthambekele ekusebenziseni i-SAP ne-MSPA, okusho ukusetshenziswa kwefilimu ye-dielectric efaka i-laminated electroless copper plating ukukhiqiza izindiza ze-copper conductive. Ngenxa yokuthi indiza yethusi incane, izifunda ezinhle zingakhiqizwa.

Enye yamaphuzu ayisihluthulelo e-SAP iwukuba i-laminate dielectric materials. Ukuze kuhlangatshezwane nezidingo zamasekhethi anembayo anomthamo omkhulu, ezinye izidingo kufanele zibekwe phambili ngezinto zokwakha ze-laminate, okuhlanganisa izakhiwo ze-dielectric, ukwahlukanisa, ukumelana nokushisa nokubopha, kanye nokuvumelana nezimo kobuchwepheshe okuhambisana ne-HDI PCB.

Ephaketheni le-semiconductor yomhlaba wonke, ama-substrates okupakisha e-IC aguqulwa asuka ku-ceramic substrates abe yi-organic substrates. Ukuphakama kwephakeji ye-FC substrates iba yincane futhi ibancane, ngakho-ke inani lamanje elijwayelekile lika-L no-S lingu-15 μm, futhi lizoba lincane.

Ukusebenza kwama-substrates anezendlalelo eziningi kufanele kugcizelele izici eziphansi ze-dielectric, i-coefficient ephansi ye-thermal expansion (CTE) kanye nokumelana nokushisa okuphezulu, okubhekisela kuma-substrates angabizi kakhulu ahlangabezana nemigomo yokusebenza. Namuhla, ubuchwepheshe be-MSPA bokufaka i-dielectric stacking buhlanganiswe ne-foil yethusi elincanyana elizosetshenziswa ekukhiqizeni ngobuningi bamasekhethi anembayo. I-SAP isetshenziselwa ukwenza amaphethini wesekethe ngawo womabili amanani we-L no-S angaphansi kuka-10 μm.

Ukuminyana okuphezulu nokubazacile kwama-PCB kubangele ama-HDI PCBs ukuthi ashintshe ukusuka ku-lamination ngama-cores kuya kuma-cores anoma yiluphi ungqimba. Kuma-HDI PCB anomsebenzi ofanayo, indawo nogqinsi lwama-PCB axhumene kunoma iyiphi ungqimba kwehliswa ngo-25% uma kuqhathaniswa nalawo anama-laminates angumongo. Kuyadingeka ukufaka ungqimba oluncane lwe-dielectric olunezici zikagesi ezingcono kulawa ma-HDI PCB amabili.

Idinga ukuthunyelwa kusuka emazingeni aphezulu kanye nesivinini esikhulu

Ubuchwepheshe bezokuxhumana nge-elekthronikhi busukela konezintambo kuye kongenantambo, ukusuka kumafrikhwensi aphansi kanye nesivinini esiphansi kuye kumafrikhwensi aphezulu kanye nesivinini esikhulu. Ukusebenza kwama-smartphones kushintshile kusuka ku-4G kuya ku-5G, okudinga isivinini esisheshayo sokudlulisela kanye namavolumu amakhulu okudlulisela.

Ukufika kwenkathi ye-computing yamafu yomhlaba wonke kuye kwaholela ekwandeni okuningi kwethrafikhi yedatha, futhi kukhona umkhuba ocacile wemishini yokuxhumana ye-high-frequency kanye nesivinini esikhulu. Ukuze kuhlangatshezwane nezidingo ze-high-frequency and high-speed transmission, ngaphezu kokunciphisa ukuphazamiseka kwesignali nokusetshenziswa, ubuqotho besignali kanye nokukhiqiza kuyahambisana nezidingo zokuklama ze-PCB design, izinto zokusebenza eziphezulu ziyisici esibaluleke kakhulu.

Umsebenzi oyinhloko kanjiniyela ukunciphisa izakhiwo zokulahlekelwa kwesignali kagesi ukwandisa isivinini se-PCB nokuxazulula izinkinga zesignali yobuqotho. Ngokusekelwe eminyakeni engaphezu kweshumi yezinsizakalo zokukhiqiza ze-PCBCart, njengesici esibalulekile esithinta ukukhethwa kwe-substrate material, lapho i-dielectric constant (Dk) ingaphansi kuka-4 kanye nokulahlekelwa kwe-dielectric (Df) kungaphansi kuka-0.010, kuthathwa njenge i-intermediate Dk/Df laminate Lapho u-Dk ingaphansi kuka-3.7 futhi i-Df ingaphansi kuka-0.005, ithathwa njenge-laminate ka-Df ephansi. Njengamanje, izinhlobonhlobo zezinto ze-substrate ziyatholakala emakethe.

Kuze kube manje, kunezinhlobo ezintathu eziyinhloko zezinto ezivame ukusetshenziswa ezisetshenziswa kakhulu zebhodi lesifunda lesifunda: ama-fluorine-based resins, ama-PPO noma ama-PPE resins nama-epoxy resins aguquliwe. I-fluorine series dielectric substrates, njenge-PTFE, inezinto eziphansi kakhulu ze-dielectric futhi ngokuvamile zisetshenziselwa imikhiqizo enefrikhwensi engu-5 GHz noma ngaphezulu. I-epoxy resin eguquliwe i-FR-4 noma i-PPO substrate ifanele imikhiqizo enobubanzi obungu-1GHz ukuya ku-10GHz.

Uma kuqhathaniswa nezinto ezintathu ze-substrate ephezulu, i-epoxy resin inenani eliphansi kakhulu, nakuba i-fluorine resin inenani eliphakeme kakhulu. Ngokuphathelene nokungaguquki kwe-dielectric, ukulahlekelwa kwe-dielectric, ukumuncwa kwamanzi, nezici zemvamisa, ama-resin asekelwe ku-fluorine enza kahle kakhulu, kuyilapho ama-epoxy resins enza kabi kakhulu. Uma i-frequency esetshenziswa umkhiqizo ingaphezulu kuka-10GHz, i-fluorine-based resin kuphela ezosebenza. Ububi be-PTFE buhlanganisa izindleko eziphezulu, ukungaqini kahle, kanye ne-coefficient ephezulu yokwandisa okushisayo.

Ku-PTFE, izinto ezingaphili ngobuningi (ezifana ne-silica) zingasetshenziswa njengezinto zokugcwalisa noma indwangu yengilazi ukuze kuthuthukiswe ukuqina kwento engaphansi kanye nokunciphisa i-coefficient yokunwetshwa okushisayo. Ukwengeza, ngenxa yokungabi namandla kwama-molecule e-PTFE, kunzima ukuthi ama-molecule e-PTFE ahlangane necwecwe lethusi, ngakho-ke ukwelashwa okukhethekile okungaphezulu okuhambisana necwecwe lethusi kumele kubonakale. Indlela yokwelapha ukwenza i-chemical etching ebusweni be-polytetrafluoroethylene ukuze kwandiswe ubuqhwaga obungaphezulu noma ukwengeza ifilimu yokunamathela ukuze kwandiswe ikhono lokunamathela. Ngokusetshenziswa kwale ndlela, izakhiwo ze-dielectric zingase zithinteke, futhi yonke i-fluorine-based high-frequency circuit kumele ithuthukiswe ngokuqhubekayo.

I-insulating resin eyingqayizivele eyenziwe nge-epoxy resin eguquliwe noma i-PPE ne-TMA, i-MDI ne-BMI, kanye nendwangu yengilazi. Ngokufanayo ne-FR-4 CCL, futhi inokumelana nokushisa okuhle kakhulu kanye nezakhiwo ze-dielectric, amandla emishini, kanye nokwenziwa kwe-PCB, konke okuyenza idume kakhulu kune-PTFE-based substrates.

Ngaphezu kwezidingo zokusebenza zezinto ezivikelayo ezifana nama-resin, ukuqina kwethusi njengomqhubi nakho kuyisici esibalulekile esithinta ukulahlekelwa kokudluliswa kwesignali, okuwumphumela womphumela wesikhumba. Ngokuyisisekelo, umphumela wesikhumba ukuthi ukungeniswa kwe-electromagnetic okukhiqizwa ekudluliselweni kwesignali ye-high-frequency kanye nomthofu we-inductive ugxila kakhulu enkabeni yendawo ephambanayo yomthofu, futhi amandla okushayela noma isiginali igxile ubuso bomthofu. Ubulukhuni obungaphezulu bekhondatha budlala indima ebalulekile ekuthonyeni ukulahlekelwa kwesignali yokudlulisela, futhi ukuhwaqeka okuphansi kuholela ekulahlekelweni okuncane kakhulu.

Ngesikhathi esifanayo, ubulukhuni obuphezulu bethusi buzobangela ukulahlekelwa kwesignali ephezulu. Ngakho-ke, ukuqina kwethusi elingaphezulu kufanele kulawulwe ekukhiqizeni kwangempela, futhi kufanele kube phansi ngangokunokwenzeka ngaphandle kokuthinta ukunamathela. Kufanele kuqashelwe kakhulu amasiginali ebangeni lefrikhwensi engu-10 GHz noma ngaphezulu. Ubulukhuni befoyili yethusi budingeka ukuthi bube ngaphansi kuka-1μm, futhi kungcono kakhulu ukusebenzisa ucwecwe lwethusi olunobuso obuphezulu obunobukhulu obungu-0.04μm. Ubulukhuni obungaphezulu be-foil yethusi kufanele buhlanganiswe nokwelashwa kwe-oxidation efanele kanye nesistimu ye-bonding resin. Esikhathini esizayo esiseduze, kungase kube ne-foil yethusi engenayo i-resin ehlanganiswe nephrofayili, enamandla amakhulu e-peel ukuvimbela ukulahlekelwa kwe-dielectric ukuthi kungathinteki.

Idinga ukumelana nokushisa okuphezulu kanye nokuchithwa okuphezulu

Ngomkhuba wokuthuthuka we-miniaturization kanye nokusebenza okuphezulu, okokusebenza kwe-elekthronikhi kuvame ukukhiqiza ukushisa okwengeziwe, ngakho-ke izidingo zokuphatha ezishisayo zemishini kagesi ziya ngokuya ziba nzima. Esinye sezixazululo zale nkinga sise ocwaningweni nasekuthuthukisweni kwama-PCB ahambisa ukushisa. Isimo esiyisisekelo sokuthi i-PCB yenze kahle mayelana nokumelana nokushisa kanye nokushabalalisa ukumelana nokushisa nekhono lokulahla le-substrate. Ukuthuthukiswa kwamanje ku-thermal conductivity ye-PCB kulele ekuthuthukisweni kwe-resin nokugcwalisa ukwengeza, kodwa kusebenza kuphela esigabeni esilinganiselwe. Indlela ejwayelekile ukusebenzisa i-IMS noma i-metal core PCB, esebenza njengezinto zokushisisa. Uma kuqhathaniswa nama-radiator nabalandeli bendabuko, le ndlela inezinzuzo zobukhulu obuncane kanye nezindleko eziphansi.

I-Aluminium iyinto ekhangayo kakhulu enezinzuzo zezinsiza eziningi, izindleko eziphansi kanye ne-conductivity enhle yokushisa. Nokuqina. Ngaphezu kwalokho, ihambisana nemvelo kangangokuthi isetshenziswa yizinsimbi eziningi zensimbi noma izintambo zensimbi. Ngenxa yezinzuzo zomnotho, uxhumano lukagesi oluthembekile, ukuqhutshwa kwe-thermal namandla aphezulu, amabhodi wesekethe angenawo ama-solder futhi angenawo umthofu, asekelwe ku-aluminium asetshenziswe emikhiqizweni yabathengi, izimoto, izimpahla zezempi kanye nemikhiqizo ye-aerospace. Akungabazeki ukuthi isihluthulelo sokumelana nokushisa nokusebenza kokuchithwa kwe-substrate yensimbi ilele ekunamatheleni phakathi kwepuleti lensimbi nendiza yesifunda.

Unganquma kanjani i-substrate material ye-PCB yakho?

Esikhathini sesimanje sika-elekthronikhi, ukuncishiswa okuncane nokubancane kwemishini kagesi kuholele ekuveleni kwama-PCB aqinile kanye nama-PCB aguquguqukayo/aqinile. Ngakho-ke hlobo luni lwe-substrate material olufanele bona?

Izindawo zokufaka izicelo ezengeziwe zama-PCB aqinile kanye nama-PCB aguquguqukayo/aqinile alethe izidingo ezintsha ngokwenani nokusebenza. Isibonelo, amafilimu e-polyimide angahlukaniswa abe yizigaba ezihlukahlukene, okuhlanganisa okusobala, okumhlophe, okumnyama nokuphuzi, okunokumelana nokushisa okuphezulu kanye ne-coefficient ephansi yokwandisa okushisayo ukuze kusetshenziswe ezimweni ezahlukene. Ngokufanayo, i-substrate yefilimu ye-polyester engabizi kakhulu izokwamukelwa yimakethe ngenxa yokunwebeka kwayo okuphezulu, ukuqina kwe-dimensional, ikhwalithi yendawo yefilimu, ukuhlanganisa izithombe zikagesi kanye nokumelana nemvelo, ukuhlangabezana nezidingo eziguqukayo zabasebenzisi.

Ngokufanayo ne-HDI PCB eqinile, i-PCB eguquguqukayo kufanele ihlangabezane nezidingo zokudlulisa isignali yesivinini esikhulu kanye nemvamisa ephezulu, futhi ukunakekelwa kufanele kukhokhwe ekulahlekeni kwe-dielectric kanye nokulahlekelwa kwe-dielectric kwezinto eziguquguqukayo ze-substrate. Isekethe eguquguqukayo ingakhiwa i-polytetrafluoroethylene kanye ne-advanced polyimide substrate. Uthuli lwe-inorganic kanye ne-carbon fiber kungangezwa kunhlaka ye-polyimide ukuze kuphumele ku-substrate enezendlalelo ezintathu eguquguqukayo ehambisa ukushisa. I-inorganic filler material ingaba i-aluminium nitride, i-aluminium oxide noma i-hexagonal boron nitride. Lolu hlobo lwezinto ze-substrate zine-conductivity eshisayo engu-1.51W/mK, ingakwazi ukumelana ne-voltage engu-2.5kV kanye ne-curvature engu-180 degrees.