Umhlangano we-PCB

I-PCBA yisifinyezo se-Printed Circuit Board Assembly, esibhekisela enqubweni yokunamathisela izingxenye ze-elekthronikhi kwi-PCB ukuze kwakhiwe uhlelo oluphelele lwesekethe. Kuyisinyathelo esibalulekile ekukhiqizweni kwemikhiqizo ye-elekthronikhi.

Ngokuyinhloko ubuchwepheshe be-Through-Hole (THT), ubuchwepheshe be-Surface Mount (SMT), kanye nobuchwepheshe be-hybrid. Izingxenye ze-THT solders ezinezintambo ezifakwe ngemigodi, izingxenye ze-SMT solders ngqo ebusweni be-PCB, kanye nobuchwepheshe be-hybrid buhlanganisa kokubili.

Izinyathelo zifaka phakathi ukulungiswa kwezinto, ukuhlolwa kwe-PCB, i-SMT (ukuphrinta i-solder paste, ukubeka izingxenye, ukugoqa kabusha), i-THT (ukucubungula i-lead, ukugoqa amagagasi), ukushisela, ukuhlolwa kwekhwalithi, ukuhlanza nokufaka i-coating, kanye nokuhlanganiswa kokugcina.

Ixhuma izingxenye ezihlukene ngokwedizayini, ivumela imisebenzi efana nokucubungula isignali kanye nokuguqulwa kwamandla. Yisinyathelo esibalulekile sokuguqula umklamo ube yimikhiqizo ebonakalayo.

Inqubo eyisisekelo iyafana, kodwa ilungiswa ngokuya ngobunkimbinkimbi bomkhiqizo, izinhlobo zezingxenye, isikali sokukhiqiza, njll. Isibonelo, imikhiqizo emincane enembile kakhulu ingase yengeze ukuhlolwa ngesandla, kuyilapho ukukhiqizwa kwesisindo kugxile ezenzakalelayo.

I-THT iwubuchwepheshe be-Through-Hole, lapho izingxenye ezinezintambo zifakwa khona emigodini ukuze zifakwe nge-solder. Izinzuzo: amandla aphezulu omshini, afanele izingxenye zamandla aphezulu; Okubi: ukusebenza okukhulu kwesikhala, ukusebenza kahle okuphansi.

I-SMT iwubuchwepheshe be-Surface Mount, obunezinzuzo zobuningi obukhulu bokuhlanganiswa, usayizi omncane wezingxenye, ukufaneleka kokukhiqizwa okuzenzakalelayo, ukusebenza kahle okuphezulu, kanye nezindleko eziphansi.

Ubuchwepheshe be-hybrid busetshenziswa lapho imikhiqizo idinga ukusebenzisa amandla aphezulu/amandla omshini we-THT kanye nobukhulu obukhulu/usayizi omncane we-SMT, njengamamojula wamandla anama-inductor angena emigodini kanye nama-chip afakwa endaweni.

Kuthonywa yizindleko zezingxenye, inani/usayizi/ubunkimbinkimbi be-PCB, ubunzima bokuhlanganisa, ivolumu yokukhiqiza, izidingo zokuhlola, njll. Amaqoqo amakhulu anciphisa izindleko zamayunithi, kuyilapho izinqubo eziyinkimbinkimbi zandisa izindleko.

Ama-elekthronikhi abathengi: izindleko eziphansi, ukuminyana okuphezulu, ukwenziwa kube kuncane; Ukulawulwa kwezimboni: ukuzinza, ukulwa nokuphazamiseka; Amadivayisi ezokwelapha: ukunemba okuphezulu nokuthembeka, okudinga ukuhambisana ngokuqinile nezindinganiso.

Izinto ezivamile njenge-FR-4 (izakhiwo zikagesi/zomshini ezinhle zemikhiqizo ejwayelekile) kanye ne-CEM-1 (izindleko eziphansi kodwa ukusebenza okuphansi). I-coefficient yokwandisa ukushisa ithinta ukuthembeka kwejoyinti le-solder; umehluko omkhulu ungabangela izinkinga zokucindezeleka.

Khetha ngokusekelwe ebunkimbinkimbi besekethe: izingqimba ezimbili zamasekethe alula, izingqimba eziningi kweziyinkimbinkimbi. Izingqimba eziningi zinikeza isikhala esiningi somzila kodwa izindleko ziphakeme, ngezidingo eziqinile zokulungiswa kwezingqimba.

Ama-PCB amakhulu kakhulu adlula imikhawulo yemishini; lawo angaphansi kobukhulu abangela ubunzima bokuphatha/ukushisisa, okuthinta ukwakheka kwezingxenye kanye nokushabalaliswa kokushisa.

Usayizi wephedi, ukuma, kanye nesikhala kuthinta ngqo ikhwalithi yokunamathisela. Amaphedi amancane kakhulu abangela amalunga omile; isikhala esiseduze kakhulu siholela ekuvaleni amasekethe amafushane.

Ukulinganisa i-solder yomoya oshisayo (HASL): izindleko eziphansi kodwa ukuthamba okubi, okuthinta ukunamathela kahle kwe-pitch; igolide lokucwiliswa kwe-nickel elingena-electro (ENIG): ukunamathela okuhle, ukunemba okuphezulu, izindleko eziphezulu; i-organic solderability preservative (OSP): ivikela ithusi, izindleko eziphakathi nendawo, izidingo zokugcina eziqinile.

Ukuhlolwa okubonakalayo (ukuklwebheka, ukuguqulwa), ukuhlolwa kwe-flying probe/ICT (ukuxhumana), ukuhlaziywa kwe-metallographic (isakhiwo sangaphakathi/ukufakwa kweplati).

Ukuhlanza ukuze kususwe ukungcola; Ama-PCB aphathwe nge-OSP adinga ukubhaka ukuze kususwe umswakama futhi kuvinjelwe amabhamuza okunamathela.

Amafayela okuklama afana ne-Gerber acacisa ukwakheka kwezingxenye kanye nezikhundla zamaphedi, asebenza njengesisekelo sokuhlanganiswa ukuqinisekisa ukuhambisana komklamo.

Izingxenye azikwazi ukufakwa, ama-short-circuits/ama-open-circuits kagesi, ukuphazamiseka kwesignali, ukushabalaliswa kokushisa okubi, okuholela ekuhlulekeni kokusebenza noma ezinkingeni zokusebenza.

Ukuhlelwa kwezingxenye okunengqondo (gwema izindawo ezixinene/ezinzima ukufinyelela kuzo), ukwakheka kwephedi okulungiselelwe kahle, ukuhambisana kwe-SMT/THT, ukubeka izimbobo, kanye nokuqondisa ukuze kugwenywe ama-engeli abukhali kanye nokulandelana okude.

Cabanga ngokusebenza kukagesi (ukufanisa ipharamitha), ukuhambisana kwephakeji namaphedi, ukuthembeka, izindleko, kanye nokuqina kokunikezwa.

Amaphakheji angena emigodini (isb., i-DIP) ye-THT, indawo enkulu yokusebenza; Amaphakheji okufaka phezulu (isb., i-SOP/BGA) ye-SMT, ukuminyana okuphezulu kodwa ubunzima obukhulu bokunamathela (isb., i-BGA idinga ukulawulwa okunembile kokushisa).

Ukungashibiliki kahle kubangela amalunga omile kanye nokushibilika okungamanga. Ama-lead anamafutha/anamafutha adinga ukwelashwa kusengaphambili (ukuhlanzwa, ukushintshwa).

Ukushiswa kabusha kwe-reflow kufaneleka izingxenye ze-SMT; ukushiswa kwamagagasi kufaneleka izingxenye ze-SMT ezinkulu. Imininingwane ivame ukusho izinqubo ezihambisanayo.

Ukukhipha kuqala (FIFO), izinga lokushisa/umswakama olawulwayo (20-25℃, 40%-60%RH), ukusampula okuvamile, kanye nokuhlolwa/ukuklebhula izingxenye eziphelelwe yisikhathi/ezisolwayo.

Umsebenzi wesekethe ongajwayelekile (amapharamitha angalungile, ukwehluleka kwe-chip), amasekethe amafushane/ukulayisha ngokweqile, kanye nomonakalo kwi-PCB nakwezinye izingxenye.

Ukuhlolwa okubonakalayo (umonakalo, ukushiswa kwe-lead), ukuhlolwa kwamapharamitha kagesi (imitha ye-multimeter/LCR), kanye nokuhlolwa kokusebenza kwezingxenye ezibalulekile (isb., ukuqinisekiswa kohlelo lwe-chip).

Ukucindezeleka okukhulu kokushisa kungabangela ukuqhekeka kwejoyinti le-solder yangaphakathi kuma-chips noma ukuwohloka kwe-dielectric kuma-capacitor, okuholela ekukhukhulekeni noma ekuhlulekeni kwamapharamitha. Iphrofayili yokushisa nesikhathi kumele kulawulwe.

Izimpawu ezihlanganisiwe (isb., i-capacitor ±, imicibisholo ye-diode) zimakwe kuma-PCB pads. Ukufakwa ngesandla kudinga ukuqinisekiswa okubonakalayo; imishini ezenzakalelayo idinga amapharamitha e-polarity ahleliwe.

Kudinga izinga lokushisa/umswakama olawulwayo (±2℃, 40%-60%RH) kanye nokuvikelwa kwe-ESD (phansi elimelene nokungaguquguquki, izintambo zesandla, izingubo zokusebenza) ukuze kugwenywe ukukhukhuleka kwamapharamitha kanye nomonakalo we-ESD.

Isimiso: Ukuphrinta i-solder paste → ukubekwa kwengxenye → ukushisa ukuze kuncibilike i-paste → ukupholisa ku-solder. Iphrofayili yezinga lokushisa: Shisa (1-3℃/s kuya ku-150-180℃), cwilisa (180-200℃, 60-120s), ukugeleza kabusha (isiqongo esingu-217-235℃, 30-90s), kupholile (3-6℃/s).

Isimiso: I-solder yoketshezi yakha igagasi, futhi ama-lead e-PCB ayashintshwa uma edlula. Kufanelekela izingxenye ze-SMT ezinkulu nezimbobo.

Izicelo: Ukudweba, ukulungisa, kanye nezindawo okunzima ukuzifinyelela ukuze zenzeka. Izinyathelo zokuphepha: Insimbi yokunamathisela engu-20-60W, ucingo lokunamathisela oluyi-0.5-1.0mm, izinga lokushisa elingu-300-350℃, isikhathi esingu-3-5s, ukuhlanza kwangaphambili, kanye nokuhlolwa ngemuva kokuhlolwa.

Khetha ngenqubo: I-solder paste engenalo i-lead (Sn-Ag-Cu, 217-227℃) yokugeleza kabusha; imigoqo ye-solder ene-lead/engenalo i-lead (Sn-Pb, 183℃ ye-lead) yokugoqa amagagasi; ucingo lwe-solder lokugoqa ngesandla, kucatshangelwa ukumanzisa kanye nezindleko.

Amapharamitha enqubo yokulawula (iphrofayili yezinga lokushisa, isikhathi sokunamathisela), ukulinganisa imishini, ukuqeqesha abasebenzi, ukusebenzisa izinto ezifanelekile, ukuhlolwa kwe-AOI/X-Ray, kanye nokulungiswa kabusha kwamaphutha ngesikhathi.

Ijoyinti elomile: Lungisa izinga lokushisa, wandise isikhathi, uhlanze izindawo; I-short circuit: Nciphisa i-solder, yenza ngcono umklamo; Ukuhlanganisa: Lungisa ivolumu yokunamathisela, iphrofayili yokushisa; I-solder enganele: Khulisa i-paste, yenza ngcono inqubo; I-solder engafanele: Engeza i-flux, lungisa izinga lokushisa.

Izindima: Susa ama-oxide, nciphisa ukucindezeleka kobuso, thuthukisa ukumanzi. Izinhlobo: Ezingaphili (umsebenzi ophezulu, ukugqwala, kudinga ukuhlanzwa), ezingaphili (umsebenzi omaphakathi, ukugqwala okuphansi, kudinga ukuhlanzwa), ezisekelwe ku-rosin (ezivamile, ezingagqwali, ezingahlanzeki). Khetha ngenqubo nangomkhiqizo.

Inani le-Tg linquma ukumelana nokushisa kwe-substrate. I-FR-4 ejwayelekile ine-Tg ~130-140℃, kuyilapho izinto ze-Tg ephezulu (≥170℃) zimelana neziqongo zokugeleza kabusha ezingama-250℃, okunciphisa ingozi yokuhlukanisa. Izinqubo ezingenayo i-lead zidinga i-Tg≥150℃.

I-SMT ejwayelekile: 4/4mil (0.1/0.1mm); Izinqubo ze-HDI zifinyelela ku-2/2mil (0.05/0.05mm) ngokuvezwa okunembile kakhulu kanye ne-copper plating engena-electro.

Landela i-IPC-7351: Ububanzi bephedi ye-QFP +0.1-0.2mm uma kuqhathaniswa nobubanzi be-lead; amaphedi angu-0603 ancoma u-0.65×0.65mm we-solder paste engu-0.04-0.06mg ngephedi ngayinye.

I-Dominant SAC305 (96.5Sn/3.0Ag/0.5Cu) iyancibilika ku-217℃, 34℃ ephakeme kune-Sn-Pb eutectic (183℃), edinga amazinga okushisa aphezulu okugeleza kabusha.

Izingxenye ze-0402: i-stencil engu-0.12mm; i-pitch engu-0.5mm BGA: i-stencil engu-0.1mm enokuvulwa kwephedi okungu-85% ukuvimbela amabhola okusonta.

IPC-A-610: I-offset yokunamathisela i-solder ≤25% yobubanzi bephedi; ≤0.1mm ye-QFP yephimbo elingu-0.4mm.

Imishini ephezulu (isb., i-Fuji NXT) ine-Cpk≥1.33, ukuphindaphindwa kwe-XY ±25μm, ukunemba kwe-θ ±0.5°, efanelekile kwizingxenye ze-0201 kanye ne-BGA yephimbo engu-0.3mm.

Ingcindezi yokubekwa kwe-MLCC: 0.3-0.5N (ingozi yokuqhekeka uma kunengcindezi ephezulu); ama-QFP lead: 0.8-1.2N uma kuqhathaniswa nezinye izinto.

Lungiselela ukunemba kokubekwa (±0.05mm), qinisekisa ivolumu yokunamathisela i-solder ehambisanayo, izinga lokugeleza kabusha kwerempu ≤3℃/s ukuze unciphise i-gradient yokushisa.

Shisa (150-180℃): irempu engu-1-2℃/s; cwilisa (180-210℃): 60-90s; ukugeleza kabusha okuphezulu 245-255℃, ≥217℃ imizuzu engu-60-90; pholile 2-4℃/s.

I-nitrogen (O₂＜500ppm) yehlisa i-oxidation futhi ithuthukisa ukumanzi, kodwa yengeza u-15-20% ezindleleni zokucubungula, ezifanele ukusetshenziswa okuthembekile kakhulu.

I-IPC-A-610 Isigaba 3: Indawo engenalutho ≤10% yendawo yebhola le-solder; izinhlelo zokusebenza ezibalulekile (isb., ezezimoto) zidinga ≤5%.

Ukusonta kwamagagasi amabili: Igagasi eliguquguqukayo licwilisa ubukhulu be-PCB obuyi-1/3-1/2; ukuphakama kwamagagasi okubushelelezi kungu-0.5-1mm ngaphansi kwephansi le-PCB.

Ukugeleza okungahlanzekile: okuqukethwe okuqinile 10%) kuthuthukisa ukumanzi kodwa kwandisa ingozi yezinsalela, okudinga ukuhlanzwa okuhambisanayo.

Ku-245-255℃ izinga lokushisa lebhodwe le-solder, isivinini singu-1.2-1.8m/min; ama-PCB ethusi ajiyile adinga i-1m/min ukuze agcwalise.

Ukushisela okungenalo umthofu: izinga lokushisa le-tip elingu-350-380℃, isikhathi sokuxhumana samasekhondi angu-≤3. Ukushisa okweqile kubangela ukuphakamisa amaphedi noma ukushiswa komthofu.

Izinhlelo zokuqondanisa ezibonakalayo (ukunemba okungu-±25μm) ezinezihlanganisi zokushintshanisa ziqinisekisa ukuphambuka okungu-＜0.1mm phakathi kwamabhola e-solder nama-pad.

Shisa ngo-150-180℃, izinga lokushisa lokulungisa kabusha lingu-320-350℃, isivinini somoya esingu-4-6 (20-30L/min) ukuze ugweme ukuguguleka komthofu.

Okumanzi: okunobungani nemvelo kodwa kudinga izinga lokushisa eliphezulu (60-80℃), ingozi yokugqwala; Isinyibilikisi (isb., i-NMP): sisebenza kahle kodwa sidinga imishini engaqhumi, imikhawulo ye-VOC.

I-IPC-TM-650: I-Ionic residue

I-AOI yesivinini esiphezulu imboza ≥95% weziphambeko zezingxenye ezingu-0402, ＞98% yama-QFP bridging/due leads, kodwa ihlushwa yizimbobo zangaphakathi ze-BGA.

I-X-Ray ye-Micro-focus ifinyelela isinqumo esingu-5μm, ithola amalunga e-BGA angu-0.3mm pitch kanye nangaphakathi kwe-PCB enezingqimba ezingu-20.

Ukutholwa kwe-ICT okunembe kakhulu kuvula ngaphansi kwe-0.1Ω, ngokumelana kokuthintana kwezinzipho okungu-100mΩ.

IPC-J-STD-033: Izingxenye ze-MSL level 3 ≤amahora angu-168 ku-30℃/60%RH; bhaka ku-125℃ amahora angu-4-8 uma kudlule.

Amalunga angu-0603: amandla amancane okudonsa ≥1.5N; Ama-QFP lead: amandla okugunda ≥5N, ngokwe-IPC-9701.

I-IPC-A-600: ≤1.5%; Ama-PCB ahlanganiswe nge-BGA ≤0.7% ukuvimbela amalunga omile.

Amadivayisi e-CMOS anokuzwela kwe-HBM

Izindleko zezinto zokwakha ziyi-40-50%, ukucubungula (kufaka phakathi ukwehla kwenani) yi-30-40%, ukuhlolwa yi-10-20%. Izindleko zeyunithi ziphakeme ngama-30-50% kunokukhiqiza ngobuningi