pcb plays lub luag haujlwm tseem ceeb hauv kev sib txuas thiab xa hluav taws xob hluav taws xob, thiab cov txheej txheem pcb electroplating tooj liab, raws li cov tub ntxhais txuas hauvpcb manufacturing txheej txheem, plays lub luag hauj lwm txiav txim siab nyob rau hauv kev ua tau zoo thiab zoo ntawm lub rooj tsav xwm Circuit Court. Los ntawm cov xov tooj smartphones mus rau siab - khoos phis tawj ua tau zoo, los ntawm cov khoom siv hluav taws xob hauv tsheb mus rau cov khoom siv dav hlau, yuav luag txhua cov khoom siv hluav taws xob 'cov ntawv luam tawm hluav taws xob cia siab rau tooj liab electroplating technology.
1, Txoj Cai ntawm Copper Electroplating
pcb electroplating ntawm tooj liab yog cov txheej txheem electrochemical raws li Faraday txoj cai. Nyob rau hauv lub da dej electroplating, pcb yog siv los ua cathode thiab tooj liab anode yog immersed nyob rau hauv ib qho electrolyte uas muaj tooj liab ions. Thaum qhov hluav taws xob ncaj qha tam sim no tau thov ntawm cathode thiab anode, tam sim no dhau los ntawm electrolyte, ua rau muaj kev cuam tshuam ntawm electrochemical.
Cov tshuaj tiv thaiv Anodic: Cov tooj liab anode dhau los ua cov tshuaj tiv thaiv oxidation, qhov twg tooj liab atoms poob ob lub electrons thiab ua tooj liab ions uas nkag mus rau hauv electrolyte. Qhov sib npaug ntawm cov tshuaj tiv thaiv yog Cu-2e ⁻ → Cu ² ⁺.
Cathodic cov tshuaj tiv thaiv: Nyob rau saum npoo ntawm pcb, tooj liab ions tau txais electrons thiab raug txo rau tooj liab atoms, uas tso rau ntawm pcb nto. Qhov sib npaug ntawm cov tshuaj tiv thaiv yog Cu ² ⁺+2e ⁻ → Cu.
Los ntawm kev tswj tsis tau xws li tam sim no ceev, electroplating lub sij hawm, thiab electrolyte muaj pes tsawg leeg, tus nqi deposition thiab txheej thickness ntawm tooj liab yuav raug tswj kom raug.
2, txheej txheem ntws
(1) Ua ntej ua
Ntxuav: Ua ntej, ntxuav lub pcb substrate kom huv si kom tshem tawm cov impurities xws li roj stains, plua plav, thiab oxides ntawm qhov chaw. Cov kev tu ib txwm muaj xws li alkaline tu, acidic tu, thiab ultrasonic tu. Kev ntxuav alkaline tuaj yeem tshem tawm cov roj thiab cov pa phem, thaum cov kua qaub ntxuav feem ntau yog siv los tshem tawm oxides. Ultrasonic tu tuaj yeem ua kom huv si huv qhov khoob thiab qhov ntawm qhov chaw ntawm lub substrate los ntawm cov nyhuv cavitation ntawm ultrasonic tsis. Lub substrate huv huv yuav tsum tsis muaj qhov pom tseeb impurities thiab nthuav tawm cov xim hlau tsis sib xws.
Micro corrosion: Lub hom phiaj ntawm micro corrosion yog tsim cov micro ntxhib saum npoo ntawm pcb nto, ua kom cov adhesion ntawm cov txheej tom ntej electroplated tooj liab thiab cov substrate. Feem ntau, cov kev daws teeb meem uas muaj micro etchants xws li persulfate lossis sulfuric acid hydrogen peroxide yog siv los kho cov substrates. Thaum lub sij hawm micro etching txheej txheem, tus neeg sawv cev micro etching tau txais cov tshuaj tiv thaiv nrog cov tooj liab, dissolving ib txheej nyias ntawm tooj liab thiab tsim cov qauv me me concave convex. Lub℃ntawm micro corrosion yuav tsum tau nruj me ntsis tswj, nrog ib tug dav micro corrosion npaum tswj ntawm 0.5-1.5 μ m los xyuas kom meej adhesion zoo tsis muaj ntau heev corrosion ntawm lub substrate.
Pre immersion: Pre immersion yog txheej txheem ntawm immersing lub ntxuav thiab micro etched pcb mus rau hauv lub pre immersion tov uas muaj tej yam Cheebtsam, tso cai rau lub substrate nto adsorb ib txheej ntawm active tshuaj thiab npaj rau cov txheej txheem ua kom tom ntej. Cov muaj pes tsawg leeg ntawm cov tshuaj ua ntej immersion feem ntau zoo ib yam li cov tshuaj ua kom muaj zog, tab sis nrog qis concentration. Nws lub luag haujlwm tseem ceeb yog los tiv thaiv lub substrate los ntawm kev oxidized dua ua ntej ua kom thiab txhim kho cov nyhuv ua kom zoo. Lub sij hawm ua ntej soaking feem ntau yog luv, feem ntau yog li ntawm ob peb feeb mus rau kaum vib nas this.
Ua kom muaj zog: Kev ua kom muaj zog yog ib qho tseem ceeb hauv cov txheej txheem ua ntej - kev kho mob, uas yog lub hom phiaj rau adsorb txheej ntawm catalytically active hlau hais, feem ntau palladium hais, nyob rau saum npoo ntawm pcb. Cov palladium particles no yuav ua cov chaw catalytic rau cov tshuaj tooj liab plating los yog electroplating, txhawb kev txo qis thiab tso nyiaj ntawm tooj liab ions. Feem ntau siv txoj kev ua kom muaj xws li colloidal palladium activation method thiab ionic palladium activation method. Colloidal palladium activation tov yog tsim los ntawm palladium ntsev, tin ntsev, thiab chelate tus neeg sawv cev. Thaum lub sij hawm ua kom cov txheej txheem, colloidal palladium hais yog adsorbed rau saum npoo ntawm pcb; Txoj kev ua kom ion palladium yog adsorb palladium ions ntawm lub substrate nto los ntawm kev sib pauv ion, thiab tom qab ntawd txo lawv mus rau hlau palladium los ntawm tus neeg sawv cev txo. Cov tsis xws li kev ua kom lub sij hawm thiab qhov kub thiab txias yuav tsum tau tswj kom meej raws li hom kev ua kom muaj kev daws teeb meem thiab cov khoom siv ntawm pcb kom ntseeg tau tias cov txheej txheem ua kom zoo ib yam thiab ntom ntom.
(2) Tshuaj tooj liab plating
Rau qee qhov pcb substrates ua los ntawm cov khoom siv tsis yog -cov khoom siv, xws li iav fiber ntau reinforced yas, chemical tooj liab plating yuav tsum tau ua ua ntej electroplating tooj liab los ua ib txheej txheej tooj liab nyias rau ntawm qhov chaw substrate, muab txoj hauv kev rau electroplating tooj liab.
Lub hauv paus ntsiab lus ntawm Chemical Copper Plating: Tshuaj tooj liab plating yog tus kheej catalytic oxidation - txo cov tshuaj tiv thaiv. Nyob rau ntawm qhov chaw nrog catalytic kev ua ub no, tooj liab ions raug txo mus rau hlau tooj liab los ntawm kev ua ntawm ib tug txo tus neeg sawv cev thiab tso rau ntawm lub substrate nto. Lub ntsiab lus sib npaug yog: Cu ² ⁺+2HCHO+4OH ⁻ → Cu+2HCOO ⁻+2H ₂ O + H ₂ ↑. Nyob rau hauv cov tshuaj tiv thaiv no, tooj liab ions raug txo kom tooj liab atoms los ntawm kev tau txais electrons nyob rau hauv lub catalysis ntawm palladium chaw, thaum formaldehyde yog oxidized rau formate ions.
Tshuaj tooj liab plating txheej txheem: Ua ntej, lub tshuab txais pcb yog raus rau hauv cov tshuaj tooj liab plating tov uas muaj tooj liab ntsev, complexing agents, txo cov neeg ua hauj lwm, thiab lwm yam additives. Qhov kub ntawm cov tshuaj plating feem ntau tswj ntawm 40-50 degree, thiab pH tus nqi yog nyob ib ncig ntawm 12-13. Nyob rau hauv tus txheej txheem ntawm electroless tooj liab plating, nws yog ib qhov tsim nyog yuav tau do lub plating tov kom tsim nyog los xyuas kom meej lub uniformity ntawm lub plating tov thiab cov kev kawm txaus ntawm cov tshuaj tiv thaiv. Lub sij hawm rau electroless tooj liab plating nyob ntawm qhov yuav tsum tau thickness ntawm cov tooj liab txheej, thiab ib txheej tooj liab nrog ib tug tuab ntawm 0.2-0.5 μ m feem ntau yuav tau. Tom qab cov tshuaj tooj liab plating, lub pcb yuav tsum tau muab ntxuav kom tshem tawm cov residual plating tov thiab impurities ntawm qhov chaw.
(3) Electroplated tooj liab
Tag nrho pawg thawj coj saib electroplated tooj liab: Tag nrho pawg thawj coj saib electroplated tooj liab, tseem hu ua thawj tooj liab, feem ntau yog siv los electroplate ib txheej ntawm tooj liab rau tag nrho cov nto ntawm ib tug pcb uas tau undergone tshuaj tooj liab plating, thiaj li yuav ua rau kom lub thickness ntawm cov tooj liab txheej, txhim kho conductivity thiab mechanical zog, thiab tiv thaiv cov tshuaj tooj liab plating txheej txheem substrate. Tag nrho cov phaj tooj liab electroplating feem ntau yog siv cov tshuaj acidic tooj liab sulfate plating, nrog tooj liab sulfate cov ntsiab lus feem ntau ntawm 150-250g / L thiab sulfuric acid cov ntsiab lus ntawm 50-200g / L hauv cov mis, nrog rau cov nyiaj tsim nyog ntawm chloride ions thiab additives. Hauv cov txheej txheem electroplating, pcb yog siv los ua cathode, thiab phosphor tooj liab npas feem ntau yog siv los ua cov anode los ntxiv cov tooj liab ions hauv cov tshuaj plating. Tam sim no qhov ceev yog feem ntau tswj ntawm 1-2A / dm ², thiab lub sij hawm electroplating nyob ntawm qhov yuav tsum tau tooj liab txheej thickness, feem ntau nce tooj liab txheej thickness mus rau 5-20 μ m. Thaum lub sij hawm tus txheej txheem ntawm electroplating tooj liab rau tag nrho lub rooj tsavxwm, nruam pom ntawm cov plating tov yog yuav tsum tau tshem tawm impurities thiab hais los ntawm lub plating tov, kom ntseeg tau qhov zoo ntawm txheej.
Graphic electroplating tooj liab: Graphic electroplating tooj liab, tseem hu ua thib ob tooj liab, yog ib qho kev xaiv electroplating ntawm qhov yuav tsum tau muaj Circuit Court graphic qhov chaw ntawm lub pcb tom qab tag nrho cov board electroplating tooj liab thiab graphic hloov lwm lub tsev, ntxiv thickening txheej tooj liab kom tau raws li qhov yuav tsum tau ntawm Circuit Court nqa peev xwm thiab teeb liab kev ua tau zoo. Cov txheej txheem thiab cov txheej txheem ntawm cov txheej txheem plating rau cov duab electroplating tooj liab zoo ib yam li cov khoom siv hluav taws xob tag nrho, tab sis vim tias tsuas yog cov duab kos duab tshwj xeeb yog electroplated, daim npog qhov ncauj yuav tsum tau npog cov khoom uas tsis tas yuav electroplating. Thaum lub sij hawm electroplating txheej txheem, tshwj xeeb yuav tsum tau them rau cov uniformity ntawm tam sim no tis kom paub meej tias cov txheej thickness ntawm txhua feem ntawm cov qauv yog zoo ib yam. Tom qab cov duab electroplating nrog tooj liab, lub thickness ntawm cov tooj liab txheej feem ntau tuaj yeem ncav cuag 20-50 μ m, thiab cov thickness tshwj xeeb yog nyob ntawm tus qauv tsim ntawm pcb.
(4) Post processing
Ntxuav: Tom qab electroplating tooj liab, lub pcb yuav tsum tau muab ntxuav kom huv si ua ntej kom tshem tawm cov residual plating tov thiab impurities ntawm qhov chaw. Kev ntxuav feem ntau siv ntau-theem countercurrent rinsing txoj kev, thawj zaug yaug nrog dej huv, thiab tom qab ntawd yaug nrog dej deionized kom ntseeg tau tias tsis muaj tshuaj lom nyob rau ntawm pcb nto. Lub pcb ntxuav yuav tsum huv si, tsis muaj stains, thiab muaj pH nqi ze rau nruab nrab.
Passivation: Yuav kom txhim kho corrosion kuj ntawm electroplated tooj liab txheej, passivation feem ntau yuav tsum tau kho. Passivation yog tsim los ntawm ib tug nyias nyias passivation zaj duab xis nyob rau saum npoo ntawm ib tug tooj liab txheej, uas muaj peev xwm tiv thaiv cov tshuaj tiv thaiv ntawm oxygen thiab noo noo thiab tooj liab, yog li ncua kev pab cuam lub neej ntawm cov tooj liab txheej. Feem ntau siv cov txheej txheem passivation muaj xws li tshuaj passivation thiab electrochemical passivation. Kev siv tshuaj lom neeg feem ntau siv cov kev daws teeb meem uas muaj chromate, phosphate, lossis organic passivators los kho cov ntawv luam tawm; Electrochemical passivation yog cov txheej txheem ntawm kev siv qee qhov hluav taws xob hauv ib qho hluav taws xob tshwj xeeb los ua oxidation cov tshuaj tiv thaiv ntawm cov txheej tooj liab, tsim cov zaj duab xis passivation. Tom qab kev kho mob passivation, qhov saum npoo ntawm cov txheej tooj liab yuav nthuav tawm ib qho xim passivation zaj duab xis xim, xws li zaj sawv los yog daj daj.
Kev ziab: Cov pcb ntxuav thiab passivated yuav tsum tau qhuav kom tshem tawm cov dej noo. Txoj kev ziab khaub ncaws muaj xws li cua kub kom qhuav, lub tshuab nqus tsev ziab, thiab lwm yam. Cov cua kub kom qhuav yog ib txoj kev siv ntau, uas yuav tsum tau muab cov pcb tso rau hauv ib qho chaw cua kub ntawm qhov kub thiab txias kom sai sai evaporate noo noo. Thaum lub sijhawm ziab, yuav tsum tau them nyiaj rau kev tswj qhov kub thiab txias kom tsis txhob pcb deformation lossis txheej tooj liab oxidation tshwm sim los ntawm qhov kub thiab txias. Lub pcb qhuav yuav tsum tau muab khaws cia kom zoo kom tsis txhob ya raws ntxiv los yog kis kab mob.