1. Isimo samanje

Wonke umuntu uyakwazi lokho ngoba ibhodi yesifunda ephrintiwe azikwazi ukusetshenzwa kabusha ngemva kokuthi zihlanganisiwe, ukulahlekelwa kwezindleko okubangelwa ukulahlwa ngenxa yama-microvoid kuphezulu kakhulu. Nakuba abayisishiyagalombili babakhiqizi be-PWB bebonile iphutha ngenxa yokubuya kwamakhasimende, amaphutha anjalo aphakanyiswa kakhulu ngumhlanganisi. Inkinga ye-solderability ayizange ibikwe ngumkhiqizi we-PWB nhlobo. Abahlanganisi abathathu kuphela abathathe ngephutha inkinga “ye-tin shrinkage” ebhodini eliwugqinsi le-high aspect ratio (HAR) elinamasinki/izindawo zokushisa ezinkulu (kubhekiselwa kunkinga ye-wave soldering). I-solder yeposi igcwaliswa kuphela kuhhafu wokujula komgodi) ngenxa yongqimba lwesiliva lokucwiliswa. Ngemva kokuba umkhiqizi wemishini yasekuqaleni (i-OEM) enze ucwaningo olunzulu nokuqinisekisa okwengeziwe ngale nkinga, le nkinga ibangelwa ngokuphelele inkinga ye-solderability ebangelwa umklamo webhodi lesifunda, futhi ayihlangene nenqubo yesiliva yokucwiliswa noma enye yokugcina. izindlela zokwelapha ezingaphezulu.

2. Ukuhlaziywa kwembangela yezimpande

Ngokuhlaziywa kwembangela yokukhubazeka, izinga lokukhubazeka lingancishiswa ngenhlanganisela yokuthuthukiswa kwenqubo kanye nokwenza kahle kwepharamitha. Umphumela we-Javanni uvame ukuvela ngaphansi kwemifantu phakathi kwe-solder mask kanye nendawo yethusi. Ngesikhathi senqubo yokucwiliswa kwesiliva, ngenxa yokuthi imifantu mincane kakhulu, ama-ion esiliva lapha anqunyelwe uketshezi lokucwiliswa kwesiliva, kodwa ithusi lapha lingagqwala libe ama-ion ethusi, bese kuba ukusabela kwesiliva kokucwiliswa kwenzeka endaweni yethusi ngaphandle kwe-copper. imifantu. . Ngenxa yokuthi ukuguqulwa kwe-ion kuwumthombo wokusabela kwesiliva kokucwiliswa, izinga lokuhlasela endaweni yethusi ngaphansi kokuqhekeka lihlobene ngokuqondile nobukhulu besiliva lokucwiliswa. 2Ag++1Cu=2Ag+1Cu++ (+ iyiyoni yensimbi elahlekelwa i-electron) imifantu ingakheka nganoma yisiphi isizathu kulezi ezilandelayo: ukugqwala okuseceleni/ukukhula ngokweqile noma ukungahlanganisi kahle kwemaski ye-solder endaweni yethusi; ungqimba lwethusi olungalingani lwe-electroplating (imbobo Indawo yethusi encane); Kukhona imihuzuko ejulile esobala esisekelweni sethusi ngaphansi kwe-solder mask.

Ukugqwala kubangelwa ukusabela kwesibabule noma umoya-mpilo emoyeni ngendawo yensimbi. Ukusabela kwesiliva nesibabule kuzokwakha ifilimu ephuzi yesiliva sulfide (Ag2S) ngaphezulu. Uma okuqukethwe kwesulfure kuphezulu, ifilimu ye-sulfide esiliva ekugcineni izoba mnyama. Kunezindlela eziningana zokuthi isiliva lingcoliswe yisibabule, umoya (njengoba kushiwo ngenhla) noma eminye imithombo yokungcola, njengephepha lokupakisha le-PWB. Ukusabela kwesiliva nomoya-mpilo kungenye inqubo, ngokuvamile umoya-mpilo kanye nethusi ngaphansi kongqimba lwesiliva kusabela ukukhiqiza i-cuprous oxide ensundu emnyama. Lolu hlobo lwesici luvame ukuthi isiliva lokucwiliswa lishesha kakhulu, lakha ungqimba lwesiliva lokucwiliswa okuphansi, okwenza ithusi engxenyeni engezansi yesendlalelo sesiliva kube lula ukuxhumana nomoya, ngakho-ke ithusi lizosabela nge-oxygen. emoyeni. Isakhiwo sekristalu esixekethile sinezikhala ezinkulu phakathi kwezinhlamvu, ngakho-ke ungqimba lwesiliva oluqinile luyadingeka ukuze kuzuzwe ukumelana ne-oxidation. Lokhu kusho ukuthi ungqimba oluyisiliva olushubile kufanele lufakwe ngesikhathi sokukhiqiza, okwandisa izindleko zokukhiqiza futhi kwandisa amathuba okuba nezinkinga zokudayiswa, njengama-microvoid kanye nokungasondeli kahle.

Ukuvezwa kwethusi kuvame ukuhlobana nenqubo yamakhemikhali ngaphambi kokucwiliswa kwesiliva. Lesi sici sivela ngemva kwenqubo yesiliva yokucwiliswa, ikakhulukazi ngoba ifilimu esele engasuswanga ngokuphelele inqubo yangaphambilini ivimbela ukubekwa kongqimba lwesiliva. Okuvame kakhulu ifilimu esalayo elethwa inqubo ye-mask solder, ebangelwa ukuthuthukiswa okungcolile kumthuthukisi, okubizwa ngokuthi “ifilimu esele”. Le filimu eyinsalela ivimbela ukusabela kwesiliva kokucwiliswa. Inqubo yokwelapha ngomshini nayo ingenye yezizathu zokuvezwa kwethusi. Isakhiwo esiphezulu sebhodi lesifunda sizothinta ukufana kokuxhumana phakathi kwebhodi nesisombululo. Ukujikeleza kwesixazululo okwanele noma okweqile kuzophinde kwakha isendlalelo sokucwiliswa kwesiliva esingalingani.

Ukungcoliswa kwe-ion Izinto ze-ionic ezikhona ebusweni bebhodi lesifunda zizophazamisa ukusebenza kukagesi webhodi lesifunda. Lawa ma-ion ikakhulukazi aphuma oketshezini oluyisiliva olucwiliswa ngokwalo (ungqimba lokucwiliswa kwesiliva luhlala noma ngaphansi kwe-solder mask). Izixazululo zesiliva zokucwiliswa ezihlukene zinokuqukethwe kwe-ion okuhlukile. Ukuphakama kokuqukethwe kwe-ion, kwandisa inani lokungcoliswa kwe-ion ngaphansi kwezimo ezifanayo zokugeza. I-porosity yongqimba lwesiliva lokucwiliswa nayo ingenye yezinto ezibalulekile ezithinta ukungcoliswa kwe-ion. Isendlalelo sesiliva esine-porosity ephezulu kungenzeka sigcine ama-ion esixazululweni, okwenza kube nzima ukugeza ngamanzi, okuzogcina kuholele ekwandeni okuhambisanayo kwenani lokungcola kwe-ion. Umphumela wangemuva kokugeza uzophinde uthinte ngqo ukungcoliswa kwe-ion. Ukugeza okunganele noma amanzi angafaneleki kuzodala ukungcoliswa kwe-ion kudlule izinga.

Ama-microvoid ngokuvamile angaphansi kwe-1mil ngobubanzi. Ama-voids atholakala ku-compound ye-metal interface phakathi kwe-solder ne-solder surface abizwa ngokuthi ama-microvoids, ngoba empeleni “ama-cavities endiza” endaweni ehlanganisiwe, ngakho ayancipha kakhulu. Amandla okushisela. Ingaphezulu le-OSP, i-ENIG nesiliva lokucwiliswa lizoba nama-microvoid. Imbangela yokwakheka kwabo ayicacile, kodwa izici eziningana ezinethonya ziye zaqinisekiswa. Nakuba wonke ama-microvoid ongqimba lwesiliva lokucwiliswa enzeka phezu kwesiliva eliwugqinsi (ugqinsi oludlula u-15μm), akuzona zonke izingqimba zesiliva eziwugqinsi ezizoba nama-microvoid. Lapho ukwakheka kwendawo yethusi ngaphansi kwesendlalelo sesiliva sokucwiliswa kubi kakhulu, ama-microvoid maningi amathuba okuthi enzeka. Ukwenzeka kwama-microvoid nakho kubonakala kuhlobene nohlobo nokwakheka kwezinto eziphilayo ezifakwe ndawonye kungqimba olusiliva. Ukuphendula lesi simo esingenhla, abakhiqizi bemishini yoqobo (i-OEM), abahlinzeki benkonzo yokukhiqiza imishini (EMS), abakhiqizi be-PWB nabaphakeli bamakhemikhali benza izifundo zokushisela ezimbalwa ngaphansi kwezimo ezifanisiwe, kodwa akekho kubo ongaqeda ngokuphelele ama-microvoid.