Cov kev kho deg dav dav ntawm PCB suav nrog tin spraying, OSP, kub immersion, thiab lwm yam “sov” ntawm no yog hais txog cov ntsiab lus ntawm kev sib txuas ntawm PCB uas muab kev sib txuas hluav taws xob ntawm cov khoom siv hluav taws xob lossis lwm lub tshuab thiab lub voj voog ntawm PCB, xws li cov ntaub qhwv. Los yog hu rau qhov txuas txuas. Lub solderability ntawm liab qab tooj liab nws tus kheej yog zoo heev, tab sis nws yog ib qho yooj yim rau oxidize thaum raug huab cua, thiab nws yog ib qho yooj yim kom kis tau. Qhov no yog vim li cas PCB yuav tsum tau kho saum npoo.

1. Txau tin (HASL)

Qhov twg perforated li dominate, yoj soldering yog txoj kev zoo tshaj plaws soldering. Kev siv cov cua kub-cua solder leveling (HASL, Kub-air solder leveling) kev kho tshuab saum npoo yog txaus kom ua tau raws li cov txheej txheem ntawm yoj soldering. Tau kawg, rau lub sijhawm uas xav tau kev sib txuas siab zog (tshwj xeeb yog kev sib txuas lus), electroplating ntawm nickel / kub feem ntau siv. . HASL yog lub ntsiab kev kho mob thev naus laus zis siv thoob ntiaj teb, tab sis muaj peb lub zog tsav tsheb tseem ceeb uas tsav cov khoom siv hluav taws xob los txiav txim siab lwm yam thev naus laus zis rau HASL: tus nqi, cov txheej txheem tshiab thiab cov kev cai tsis muaj hlau lead.

Los ntawm tus nqi ntawm qhov pom, ntau yam khoom siv hluav taws xob xws li kev sib txuas lus hauv xov tooj thiab cov khoos phis tawj ntawm tus kheej tau dhau los ua cov khoom siv nrov. Tsuas yog los ntawm kev muag ntawm tus nqi lossis tus nqi qis dua tuaj yeem ua rau peb invincible hauv kev sib tw hnyav. Tom qab kev txhim kho ntawm kev sib dhos tshuab rau SMT, PCB pads xav tau kev tshuaj ntsuam luam ntawv thiab cov txheej txheem rov ua dua thaum lub sij hawm sib dhos. Nyob rau hauv cov ntaub ntawv ntawm SMA, cov txheej txheem kev kho mob ntawm PCB tseem siv HASL thev naus laus zis, tab sis raws li SMT cov cuab yeej txuas ntxiv zuj zus, cov ntaub qhwv thiab cov stencil qhib tau me dua, thiab qhov tsis zoo ntawm HASL thev naus laus zis tau maj mam nthuav tawm. Cov ntaub qhwv ua tiav los ntawm HASL thev naus laus zis tsis tiaj txaus, thiab kev sib koom ua ke tsis tuaj yeem ua tau raws li cov txheej txheem ntawm cov ntaub qhwv zoo. Kev txhawj xeeb txog ib puag ncig feem ntau tsom rau qhov muaj feem cuam tshuam ntawm txhuas rau ib puag ncig.

2. Organic Solderability Protective Layer (OSP)

Organic solderability preservative (OSP, Organic solderability preservative) yog cov organic txheej siv los tiv thaiv oxidation ntawm tooj liab ua ntej soldering, uas yog, los tiv thaiv cov solderability ntawm PCB pads los ntawm kev puas tsuaj.

Tom qab lub PCB nto yog kho nrog OSP, ib tug nyias organic compound yog tsim nyob rau saum npoo ntawm tooj liab los tiv thaiv tooj liab los ntawm oxidation. Lub thickness ntawm Benzotriazoles OSP feem ntau yog 100 A °, thaum lub thickness ntawm Imidazoles OSP yog thicker, feem ntau 400 A °. OSP zaj duab xis yog pob tshab, nws tsis yooj yim rau kev paub qhov txawv ntawm nws lub neej nrog lub qhov muag liab qab, thiab nws nyuaj rau kev kuaj xyuas. Thaum lub sij hawm sib dhos txheej txheem (reflow soldering), OSP yog yooj yim yaj mus rau hauv lub solder paste los yog acidic Flux, thiab nyob rau tib lub sij hawm lub active tooj liab nto raug, thiab thaum kawg Sn / Cu intermetallic tebchaw yog tsim ntawm lub Cheebtsam thiab cov ntaub qhwv. Yog li ntawd, OSP muaj cov yam ntxwv zoo heev thaum siv los kho qhov chaw vuam. OSP tsis muaj teeb meem ntawm cov hmoov txhuas, yog li nws yog ib puag ncig zoo.

Kev txwv ntawm OSP:

①. Txij li OSP yog pob tshab thiab tsis muaj xim, nws yog ib qho nyuaj rau kev soj ntsuam, thiab nws yog ib qho nyuaj rau kev paub qhov txawv ntawm cov PCB tau coated nrog OSP.

② OSP nws tus kheej yog rwb thaiv tsev, nws tsis ua hluav taws xob. OSP ntawm Benzotriazoles kuj yog nyias, uas tej zaum yuav tsis cuam tshuam rau qhov kev ntsuam xyuas hluav taws xob, tab sis rau OSP ntawm Imidazoles, cov yeeb yaj kiab tiv thaiv tsim yog tuab heev, uas yuav cuam tshuam rau kev kuaj hluav taws xob. OSP tsis tuaj yeem siv los tswj cov hluav taws xob tiv tauj, xws li cov keyboards rau cov yuam sij.

③ Thaum lub sij hawm vuam txheej txheem ntawm OSP, yuav tsum muaj zog Flux, txwv tsis pub cov yeeb yaj kiab tiv thaiv tsis tuaj yeem raug tshem tawm, uas yuav ua rau vuam tsis xws luag.

④ Thaum lub sijhawm khaws cia, qhov chaw ntawm OSP yuav tsum tsis txhob raug cov kua qaub, thiab qhov kub thiab txias yuav tsum tsis txhob siab dhau, txwv tsis pub OSP yuav volatilize.

3. Kub Kub (ENIG)

ENIG txoj kev tiv thaiv mechanism:

Ni/Au yog plated rau ntawm qhov chaw tooj liab los ntawm kev siv tshuaj. Lub deposition thickness ntawm lub puab txheej ntawm Ni yog feem ntau 120 mus rau 240 μin (kwv yees li 3 mus rau 6 μm), thiab lub deposition thickness ntawm lub txheej txheej ntawm Au yog kuj nyias, feem ntau 2 mus rau 4 μinch (0.05 mus rau 0.1 μm). Ni tsim ib txheej txheej ntawm cov solder thiab tooj liab. Thaum lub sij hawm soldering, Au nyob rau sab nraud yuav sai sai yaj rau hauv lub solder, thiab cov solder thiab Ni yuav tsim ib tug Ni / Sn intermetallic compound. Cov kub plating sab nraud yog tiv thaiv Ni oxidation los yog passivation thaum lub sij hawm cia, yog li cov kub plating txheej yuav tsum ntom txaus thiab lub thickness yuav tsum tsis txhob nyias dhau.

Immersion kub: Nyob rau hauv cov txheej txheem no, lub hom phiaj yog tso ib tug nyias thiab nruam kub tiv thaiv txheej. Lub thickness ntawm lub ntsiab kub yuav tsum tsis txhob tuab heev, txwv tsis pub cov pob qij txha solder yuav nkig heev, uas yuav cuam tshuam rau kev ntseeg siab ntawm vuam. Zoo li npib tsib xee plating, immersion kub muaj qhov kub thiab txias ua haujlwm ntev. Thaum lub sij hawm dipping txheej txheem, ib qho kev hloov pauv yuav tshwm sim – ntawm qhov chaw ntawm npib tsib xee, kub hloov npib tsib xee, tab sis thaum qhov kev hloov pauv mus txog ib theem, qhov kev hloov pauv yuav tsum nres. Kub muaj lub zog siab, ua haujlwm tsis zoo, kub tsis kam, thiab tsis yooj yim rau oxidize, yog li nws tuaj yeem tiv thaiv npib tsib xee los ntawm oxidation lossis passivation, thiab tsim nyog rau kev ua haujlwm hauv kev siv zog siab.

Lub PCB nto kho los ntawm ENIG yog tiaj tus heev thiab muaj kev sib raug zoo, uas tsuas yog siv rau kev sib cuag ntawm lub pob. Qhov thib ob, ENIG muaj qhov zoo tshaj plaws solderability, kub yuav yaj sai sai rau hauv cov molten solder, yog li nthuav tawm Ni.

Kev txwv ntawm ENIG:

ENIG cov txheej txheem yog qhov nyuaj dua, thiab yog tias koj xav ua tiav cov txiaj ntsig zoo, koj yuav tsum tswj hwm cov txheej txheem tsis tu ncua. Qhov teeb meem tshaj plaws yog tias PCB nto kho los ntawm ENIG yog qhov ua rau cov pawm dub thaum ENIG lossis soldering, uas yuav muaj kev cuam tshuam loj heev rau kev ntseeg siab ntawm cov pob qij txha. Lub tiam mechanism ntawm cov dub disk yog heev nyuaj. Nws tshwm sim ntawm lub interface ntawm Ni thiab kub, thiab nws yog ncaj qha manifested li oxidation ntau dhau ntawm Ni. Cov kub ntau dhau yuav ua rau cov pob qij txha thiab ua rau muaj kev ntseeg siab.

Txhua qhov txheej txheem kho saum npoo muaj nws tus kheej tshwj xeeb, thiab qhov kev thov ntawm daim ntawv thov kuj txawv. Raws li daim ntawv thov ntawm cov laug cam sib txawv, qhov kev kho deg sib txawv yuav tsum tau ua. Raws li kev txwv ntawm cov txheej txheem ntau lawm, qee zaum peb muab cov lus qhia rau cov neeg siv khoom raws li cov yam ntxwv ntawm cov laug cam. Qhov laj thawj tseem ceeb yog kom muaj qhov tsim nyog qhov chaw kho raws li tus neeg siv khoom daim ntawv thov khoom thiab lub tuam txhab cov txheej txheem muaj peev xwm. s Xaiv.