PCB cov kev xav tau rau non-electrolytic nickel txheej

Electroless npib tsib xee txheej yuav tsum ua kom tiav ntau yam haujlwm:

Kub deposit nto

Lub hom phiaj tseem ceeb ntawm Circuit Court yog tsim kom muaj kev sib txuas ntawm PCB thiab cov khoom siv nrog lub cev muaj zog thiab cov yam ntxwv zoo hluav taws xob. Yog tias muaj cov oxide lossis cov kab mob sib kis rau ntawm PCB nto, qhov kev sib txuas ntawm cov soldered no yuav tsis tshwm sim nrog cov dej tsis muaj zog niaj hnub no.

Kub ib txwm precipitates ntawm nickel thiab yuav tsis oxidize thaum lub sij hawm ntev cia. Txawm li cas los xij, kub tsis precipitate ntawm oxidized npib tsib xee, yog li cov npib tsib xee yuav tsum nyob twj ywm ntshiab ntawm cov nickel da dej thiab dissolution ntawm kub. Nyob rau hauv txoj kev no, thawj qhov yuav tsum tau ntawm npib tsib xee yog nyob twj ywm tsis muaj oxidation ntev txaus kom tso cai rau nag lossis daus ntawm kub. Cov tivthaiv tau tsim cov tshuaj immersion da dej kom tso cai 6-10% phosphorus cov ntsiab lus hauv nag lossis daus ntawm npib tsib xee. Cov ntsiab lus phosphorus no hauv cov txheej electroless npib tsib xee yog suav tias yog kev sib npaug ntawm kev tswj da dej, oxide, thiab hluav taws xob thiab lub cev.

hardness

Cov txheej tsis-electrolytic npib tsib xee txheej yog siv rau hauv ntau daim ntawv thov uas xav tau lub cev muaj zog, xws li tsheb sib kis kabmob. PCB cov kev xav tau tsis tshua muaj zog dua li cov ntawv thov no, tab sis rau kev sib txuas xov tooj

(Wire-bonding), kov ncoo cov ntsiab lus, plug-in connector (ntug-connetor) thiab kev ua haujlwm ruaj khov, qee qhov kev nyuaj siab tseem ceeb heev. Hlau sib txuas yuav tsum muaj nickel hardness. Yog tias cov hlau lead deforms qhov tso nyiaj, qhov poob ntawm kev sib txhuam yuav tshwm sim, uas pab cov hlau lead “melt” rau substrate. Daim duab SEM qhia tau hais tias tsis muaj kev nkag mus rau saum npoo ntawm npib tsib xee / kub lossis npib tsib xee / palladium (Pd) / kub.

Cov yam ntxwv hluav taws xob

Vim nws yooj yim ntawm fabrication, tooj liab yog cov hlau ntawm kev xaiv rau Circuit Court tsim. Lub conductivity ntawm tooj liab yog superior rau yuav luag txhua hlau. Kub kuj muaj cov hluav taws xob zoo conductivity thiab yog qhov kev xaiv zoo tshaj plaws rau cov hlau sab nraud, vim tias cov hluav taws xob zoo li ntws mus rau saum npoo ntawm txoj kab hluav taws xob (“nto” txiaj ntsig).

Tooj 1.7 µΩcm Kub 2.4 µΩcm Nickel 7.4 µΩcm Electroless npib tsib xee plating 55 ~ 90 µΩcm Txawm hais tias cov yam ntxwv hluav taws xob ntawm feem ntau cov laug cam tsis cuam tshuam los ntawm cov nickel txheej, npib tsib xee tuaj yeem cuam tshuam cov yam ntxwv hluav taws xob ntawm high-frequency signals. Lub teeb liab poob ntawm microwave PCB tuaj yeem tshaj tus tsim qauv. Qhov tshwm sim no yog proportional rau lub thickness ntawm npib tsib xee-lub Circuit Court yuav tsum dhau los ntawm cov npib tsib xee kom ncav cuag cov pob qij txha. Hauv ntau daim ntawv thov, cov teeb liab hluav taws xob tuaj yeem rov qab los rau hauv cov qauv tsim tshwj xeeb los ntawm kev qhia tias qhov tso nyiaj npib tsib xee tsawg dua 2.5 µm.

Hu tau tiv

Kev tiv thaiv kev tiv thaiv yog qhov sib txawv ntawm kev sib tw vim tias cov nickel / kub nto tseem tsis tau siv thoob plaws hauv lub neej ntawm cov khoom kawg. Nickel / kub yuav tsum tswj cov hluav taws xob conductivity rau sab nraud kev sib cuag tom qab ib puag ncig mus ntev. Antler’s 1970 phau ntawv qhia txog kev tiv tauj ntawm nickel / kub qhov chaw hauv cov ntsiab lus ntau. Ntau qhov chaw siv qhov kawg tau kawm: 3 “65 ° C, qhov kub siab tshaj plaws rau cov tshuab hluav taws xob uas ua haujlwm ntawm chav tsev kub, xws li khoos phis tawj; 125 ° C, qhov kub ntawm qhov sib txuas dav dav yuav tsum ua haujlwm, feem ntau teev rau kev siv tub rog; 200 ° C, qhov kub no tau dhau los ua qhov tseem ceeb rau cov khoom siv dav hlau. “

Rau qhov kub thiab txias ib puag ncig, tsis muaj nickel barrier yuav tsum tau. Raws li qhov kub thiab txias, cov nyiaj npib tsib xee yuav tsum tau tiv thaiv nickel / kub hloov mus nce.

Nickel barrier txheej Txaus siab rau ntawm 65 ° C Txaus siab rau ntawm 125 ° C Txaus siab rau ntawm 200 ° C 0.0 µm 100% 40% 0% 0.5 µm 100% 90% 5% 2.0 µm 100% 100 µm 10% 4.0. % 100%