Iphakheji ye-Flip-Chip: Izinto Okucatshangwa Ngazo Ngesakhiwo, Inqubo, kanye Nobunjiniyela

1. Iyini iphakheji ye-Flip-Chip?

Iphakheji ye-flip-chip iwubuchwepheshe bokuxhumana obusezingeni le-die lapho i-semiconductor die ifakwe khona ibheke phansi, ubuso bayo obusebenzayo bubheke phansi. Ngokungafani nokubopha ngocingo, okuhambisa amasignali kusuka emphethweni we-die, ukuxhumana kwe-flip-chip kusebenzisa ama-solder bumps noma ama-micro bumps abekwe ngqo kuma-I/O pads.

Lawa maqhubu akha ukuxhumana kukagesi nokwemishini phakathi kwedayi kanye ne-substrate noma i-PCB. Lo mklamo oqondile we-bump-to-pad ufinyeza ngokuyisisekelo indlela yesignali futhi uqeda ukungasebenzi kahle kwe-parasitic okukhona kuma-wire loops.

2. Isakhiwo Esiyisisekelo Sephakheji Ye-Flip-Chip

Ama-Silicon Die kanye nama-I/O Pads

I-silicon die iqukethe yonke i-active circuitry, enama-aluminium noma ama-copper I/O pads asatshalaliswa endaweni esebenzayo. Ekucushweni kwe-flip-chip, lawa ma-pads awagcini nje emngceleni we-die. Ukuhlelwa kwama-area-array pad kuvumela ukubalwa kwe-I/O okuphezulu kakhulu ngaphakathi kwe-die footprint efanayo, okusekela ngqo izidingo zobuningi bama-processor anamuhla nama-ASIC.

Amaqhubu e-Solder

Ama-solder bumps, ngokuvamile i-C4 (Controlled Collapse Chip Connection) noma ama-micro bumps, asebenza njengabaqhubi bakagesi kanye nama-mechanical anchors. I-Bump pitch inquma ubukhulu be-I/O obungafinyeleleka; amaphakheji amanje athuthukile asebenza kuma-pitches angaphansi kuka-100 µm. I-bump metallurgy ivame ukuhilela ama-alloy angenawo umthofu njenge-SnAgCu, akhethelwe ukuthembeka nokuhambisana nemvelo.

Izinto Zokugcwalisa Ngaphansi

I-Underfill iyinto esuselwe ku-epoxy ekhishwa esikhaleni esiphakathi kwe-die ne-substrate ngemva kokugeleza kabusha. Isabalalisa kabusha ukucindezeleka kwe-thermomechanical kuyo yonke indawo ye-die esikhundleni sokuyigxilisa emajoyintini e-solder ngamanye. Ngaphandle kwe-underfill, ukungafani kwe-CTE phakathi kwe-silicon ne-organic substrates kungabangela ukwehluleka okusheshayo kokukhathala kwe-solder ngaphansi kokujikeleza kokushisa.

Izixhumi ze-Substrate kanye nezixhumi zangaphandle

I-substrate yephakheji inikeza ukuhanjiswa kwesignali, ukusatshalaliswa kwamandla, kanye nokusekelwa kwemishini. Ekulungiselelweni kwe-FCBGA, amabhola e-solder phansi kwe-substrate axhuma kwi-PCB yesistimu. Izinto ze-substrate ezifana ne-BT resin noma i-ABF (i-Ajinomoto Build-up Film) zikhethwa ngokusekelwe ezimpahleni ze-dielectric, izidingo zokubalwa kwezingqimba, kanye nokusebenza kokushisa.

3. Iphakheji ye-Flip-Chip vs Ukubopha Kwezintambo Zendabuko

Ubude Bokuxhumana kanye Nezimbungulu Zikagesi

Amabhondi entambo aletha ubude be-loop obuyi-millimeter obuhambisana ne-inductance kanye nokumelana. Ama-flip-chip bumps alinganisa amashumi ama-micrometer ukuphakama, okunciphisa i-inductance yokuxhumana ngokulandelana kobukhulu. Lo mehluko uthinta ngqo ubuqotho besiginali kumaza e-GHz kanye nokusebenza kahle kokulethwa kwamandla ngaphansi kwemithwalo yamandla aphezulu.

Ubuningi be-I/O kanye nendlela yokushisa

Ukubopha ngentambo kuvimbela i-I/O emngceleni we-die, kunciphisa ukukala kobuningi. I-Flip-chip ivumela ukusetshenziswa okugcwele kwe-area-array, isekela izinkulungwane zokuxhumeka kwe-I/O. Ngokwesimo sezulu, i-die backside kumaphakheji e-flip-chip ingaxhunywa ngqo ku-heat spreader, inikeze indlela yokushisa ephikiswa kancane amaphakheji aboshwe ngentambo angenakukwazi ukuyifanisa ngaphandle kobunzima obengeziwe.

Isikhundla Ekukhetheni Ukupakisha

I-Flip-chip ayiyona indawo evamile yokubopha intambo. Ibhekana nezidingo ezithile: inani eliphezulu le-I/O, ubuqotho besignali obuqinile, kanye nokusabalala okuphezulu kokushisa. Ukubopha intambo kuhlala kungabizi kakhulu kumadivayisi ayinkimbinkimbi kancane lapho la mapharamitha engabalulekile kangako.

4. Inqubo Yokupakisha I-Flip-Chip

Ukwakheka Kweziqhubu

Amaqhubu akheka ezingeni le-wafer ngezinqubo zokufaka i-electroplating noma zokuhwamuka. Amaqhubu e-solder e-C4 ahlala ejwayelekile ezinhlelweni eziningi, kuyilapho amaqhubu e-Cu pillar anezivalo ze-solder ebhekana nezidingo ze-pitch ezincanyana. Inqubo yokwakheka kwamaqhubu ichaza ubukhulu obubalulekile obunquma ukuvunwa kokuhlanganiswa kanye nokuthembeka kwesikhathi eside.

I-Wafer Dicing

Ngemva kokugoqa, i-wafer ifakwa ibe yidayi ngayinye. Ukugoqa kumele kugcine ubuqotho be-bump futhi kugweme ukugoqa komphetho okungalimaza amandla edayi. Ukugoqa ama-blade kanye nokugoqa nge-laser kukhethwa ngokusekelwe ekujikeni kwe-wafer, ukucushwa kwe-bump, kanye nezidingo zokuphuma.

Ukubekwa Kwe-Die kanye Nokugeleza Kabusha

Idayi iyaphendulwa bese ibekwa phezu kwe-substrate enezimbobo ezihambisana nama-pad ahambisanayo. Ngesikhathi sokugeleza kabusha, ukucindezeleka kobuso be-solder kunikeza ukuzivumelanisa, okukhokhela amaphutha amancane okubeka. Amaphrofayili okugeleza kabusha kumele alinganisele ukumanzisa okuphelele kwe-solder ngokumelene nokukhula ngokweqile kwe-intermetallic.

Ukusabalalisa Nokuphola Okungaphansi Kokugcwalisa

Ukugcwalisa ngaphansi kwe-capillary kukhishwa eceleni komphetho we-die bese kudonswa esikhaleni ngesenzo se-capillary. Ukugcwaliswa okuphelele ngaphandle kwezikhala kubalulekile; ama-air pockets abanjiwe aba yizindawo zokugxila ekucindezelekeni kanye nezindawo zokuqala ukugqwala. Ukushisa okushisa kuhlanganisa i-epoxy, kusungula izakhiwo zokugcina zemishini.

Ukuhlanganiswa Kwephakheji Yokugcina

Kumaphakheji e-flip-chip yohlobo lwe-BGA, amabhola e-solder anamathiselwa phansi kwe-substrate bese ephinde ageleze. Iphakheji eliqediwe lihlolwa ngogesi futhi lihlolwe ngokubonakalayo ngaphambi kokuthunyelwa. Izilawuli zenqubo esinyathelweni ngasinye zinquma isivuno sokuhlanganiswa okuphelele.

5. Izinto Ezibalulekile Ekupakisheni Ama-Flip-Chip

Ama-Solder Alloys

Ama-alloy angenawo umthofu, ikakhulukazi i-SnAgCu (SAC), aseyindinganiso yemboni. Ukwakheka kwe-alloy kuthinta iphuzu lokuncibilika, ukuziphatha kokumanzisa, kanye nezakhiwo zemishini. Okuqukethwe kwesiliva okuphezulu kuthuthukisa ukumelana nokukhathala kodwa kwandisa izindleko; ukukhethwa kwe-alloy kulinganisela izidingo zokuthembeka ngokumelene nezithiyo zomnotho.

Izinto Zokungagcwalisi Ngaphansi

Ama-formulations angaphansi kokugcwalisa aklanywe ukuze afane ne-CTE yesistimu ye-solder kanye ne-substrate. Usayizi wezinhlayiya zokugcwalisa kanye nomthwalo kuthinta izici zokugeleza kanye ne-modulus yokugcina. Ama-underfill angaphinde asebenze akhona kodwa alahlekelwa ukusebenza okuthembekile uma kuqhathaniswa nama-formulations ajwayelekile.

Izinto ze-substrate kanye ne-RDL

Ama-substrate e-organic asebenzisa i-BT resin noma izendlalelo zokwakheka kwe-ABF kuye ngokuthi inani lezingqimba kanye nezidingo zosayizi wesici lingakanani. Izingqimba zokusabalalisa kabusha (RDL) ku-die noma i-substrate zixhumanisa i-fan out fine-pitch bump kuya ezicini ze-substrate eziqinile. Ukukhethwa kwezinto kuthinta ngqo ukusebenza kukagesi, ukuziphatha kwe-warpage, kanye nesivuno sokukhiqiza.

6. Ukusebenza Ngogesi Nokushisa Kwamaphakheji E-Flip-Chip

Izinzuzo Zobuqotho Besignali

Ubude bokuxhumana obuncishisiwe buholela ekungeneni okuphansi kanye nokulawulwa kwe-impedance okuthuthukisiwe. Amasignali emvamisa ephezulu ahlangabezana nokuncishiswa okuncane kanye nokubonakaliswa okuncane. Lezi zici zenza ukupakishwa kwe-flip-chip kubaluleke kakhulu kumaprosesa asebenza kumaza ewashi le-multi-GHz kanye nezixhumi ze-serial zesivinini esikhulu.

Ukulethwa Kwamandla Nokushabalaliswa Kwezimo Ezishisayo

Ama-power bump amaningi kanye nama-ground bumps asatshalaliswa endaweni ye-die anciphisa ukwehla kwamandla okumelana. I-die eveziwe ngemuva ivumela ukunamatheliswa kwe-heat spreader okuqondile, okunikeza amanani okumelana nokushisa angafinyeleleki ngokulungiswa okune-wire-bond. Ama-processor anamandla aphezulu kanye nama-GPU ancike kulolu hlobo lwe-thermal architecture.

7. Iphakheji ye-Flip-Chip: Izinselele Zomshini Nokukhiqiza

Ukungafani kwe-CTE kanye nokukhathala kwe-Solder

I-Silicon (CTE ~3 ppm/°C) kanye ne-organic substrates (CTE ~15-17 ppm/°C) zanda ngamazinga ahlukene ngesikhathi sokuvakasha kokushisa. Lokhu kungafani kubangela ukucindezeleka kwe-shear emajoyintini e-solder, okuholela ekuqalisweni kokuqhekeka kokukhathala kanye nokusabalala. Ukugcwalisa okungaphansi kokugcwalisa kunciphisa kodwa akukususi lokhu kukhathazeka okuyisisekelo kokuthembeka.

Ukulawulwa Kwenqubo Yokugcwalisa Okungaphansi

Ukumbozwa okungaphelele kwe-underfill noma i-void entrapment kudala amaphuzu abuthakathaka okuthembeka. Amapharamitha okukhipha, izinga lokushisa le-substrate, kanye ne-viscosity ye-underfill kumele kulawulwe ngokuqinile. Amanani okuvala ayanda njengoba i-bump pitch incipha, okuletha izinselele eziqhubekayo zobunjiniyela bezinqubo kuma-node athuthukile.

Ukuzwela kwe-Warpage kanye ne-Yield

Ukugoba kwephakheji kuthinta kokubili ukuvunwa kwenhlangano kanye nokuthembeka kwezinga lebhodi. I-die enkulu kuma-substrate amancane isengozini kakhulu. Ama-fine-pitch bumps adinga ukunemba kokubekwa okuqinile kanye nokubekezelelana kwe-coplanarity, okwandisa umthelela wokuvunwa kwanoma yikuphi ukushintshashintsha kwenqubo.

8. Izinhlobo Ezivamile Zamaphakheji E-Flip-Chip

I-FCOB kanye ne-FCCSP

I-Flip-Chip on Board (FCOB) ifaka idayisi ngqo kwi-PCB yesistimu ngaphandle kwe-substrate yephakheji ephakathi, inciphisa usayizi kanye nezindleko zezinhlelo zokusebenza ezifanele. I-Flip-Chip Chip Scale Package (FCCSP) isebenzisa i-substrate encane, igcina indawo ecishe ibe yinde ngenkathi inikeza ukuguquguquka komzila.

I-FCBGA

I-Flip-Chip Ball Grid Array (FCBGA) ihlanganisa i-flip-chip die attach ne-interface ye-BGA substrate. Lokhu kulungiselelwa kusekela umzila oyinkimbinkimbi we-multi-layer, ama-passive ahlanganisiwe, kanye nokubalwa okuphezulu kwe-I/O. I-FCBGA ibusa izinhlelo zokusebenza zokubala ezisebenza kahle kakhulu kufaka phakathi ama-processor eseva kanye nama-ASIC enethiwekhi.

9. Ukusetshenziswa Okuvamile Kokupakisha Ama-Flip-Chip

I-High-Performance Computing

Ama-CPU, ama-GPU, kanye nama- FPGA aphezulu asebenzisa yonke indawo ukupakishwa kwe-flip-chip. Inhlanganisela yokuminyana okuphezulu kwe-I/O, ukusebenza kahle kukagesi, kanye nokusatshalaliswa kokushisa okuphumelelayo kubhekana nezidingo zala madivayisi ngesikhathi esisodwa. Izinhlelo zokusebenza zesikhungo sedatha kanye ne-AI accelerator ziqhuba intuthuko eqhubekayo yobuchwepheshe be-flip-chip.

Ukuxhumana, i-RF, kanye nezimoto

Ama-ASIC okushintsha inethiwekhi kanye nama-amplifiers e-RF power azuza ezixhumanweni ze-flip-chip eziphansi. Ama-elekthronikhi ezimoto asebenzisa kakhulu i-flip-chip ezinhlelweni zokusiza abashayeli ezithuthukisiwe lapho ubuqotho besignali kanye nokuphathwa kokushisa kubalulekile khona. Amadivayisi abathengi afana nama-smartphone asebenzisa i-FCCSP kuma-processor ohlelo lokusebenza.

10. Ukuthembeka Nokuhlolwa Kwephakheji Ye-Flip-Chip

Izindlela Zokwehluleka Ezivamile

Ukuqhekeka kwe-solder bump ngenxa yokukhathala kwe-thermomechanical kumelela indlela eyinhloko yokuguguleka. Ukususwa kwe-underfill kusuka endaweni ye-die noma ye-substrate kuveza amalunga e-solder ekucindezelekeni okusheshayo. Ukufuduka kwe-electromagnetic kuma-bumps anomoya ophezulu kungabangela ukwehluleka okuvulekile ezindleleni zokulethwa kwamandla.

Izindlela Zokuhlola

Ukuhlolwa kwe-X-ray kwembula izikhala ezigobhozayo, ukungalungi kahle, kanye neziphambeko zokuvala. Ukuskena i-acoustic microscopy (i-SAM) kuthola izikhala ezingaphansi kokugcwalisa kanye nokuhlukanisa. Ukuhlolwa kukagesi kuqinisekisa ukuxhumana kanye nokusebenza kwe-parametric. Lezi zindlela zihlanganisa ukuhlola amayunithi anephutha nokuqapha ikhono lenqubo.

11. Kufanele Bakhethe Nini Iphakheji Ye-Flip-Chip?

Imibandela Yesinqumo

Ukupakishwa kwe-flip-chip kuyaqinisekiswa uma inani le-I/O lidlula imikhawulo esebenzayo yokubopha izintambo, ngokuvamile lingaphezu kokuxhumeka okungu-500-700. Amaza esignali kububanzi be-GHz azuza ezifweni ezincishisiwe zokuxhuma. Izidingo zokushabalalisa ukushisa ezingaphezu kuka-10-15W zisekela indlela eqondile yokushisa enikezwa yi-flip-chip.

Ukucatshangelwa Kwengqalasizinda Nezindleko

Ukuhlanganiswa kwe-flip-chip kudinga imishini ekhethekile yokubeka, ukugeleza kabusha, kanye nokugcwalisa okungaphansi. Izindleko ze-substrate zidlula ezinye izindlela ze-leadframe. Onjiniyela kumele bahlole ukuthi izidingo zokusebenza ziyavumelana yini nezindleko zeprimiyamu futhi baqinisekise ukuthi abalingani bokuhlanganiswa banekhono elidingekayo lenqubo kanye nezinhlelo zekhwalithi.