Kev ceev faj rau kev xaiv ntau txheej PCB cov ntaub ntawv dielectric

Txawm hais tias lub laminated qauv ntawm lub Multilayer PCB, cov khoom kawg yog laminated qauv ntawm tooj liab ntawv ci thiab dielectric. Cov ntaub ntawv uas cuam tshuam rau kev ua haujlwm hauv Circuit Court thiab kev ua haujlwm ntawm cov txheej txheem yog cov khoom siv dielectric. Yog li, kev xaiv ntawm PCB pawg thawj coj saib feem ntau yog xaiv cov khoom siv hluav taws xob, suav nrog prepregs thiab core boards. Yog li dab tsi yuav tsum tau them sai sai rau thaum xaiv?

1. iav hloov kub (Tg)

Tg yog cov khoom tshwj xeeb ntawm cov khoom siv polymers, qhov kub thiab txias tseem ceeb uas txiav txim siab cov khoom siv, thiab qhov tseem ceeb ntawm kev xaiv cov khoom siv substrate. Qhov kub ntawm PCB tshaj Tg, thiab thermal expansion coefficient yuav loj dua.

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Raws li Tg kub, PCB boards feem ntau muab faib ua Tg qis, nruab nrab Tg thiab siab Tg boards. Hauv kev lag luam, cov laug cam nrog Tg nyob ib ncig ntawm 135 ° C feem ntau yog cais raws li cov laug cam qis-Tg; boards nrog Tg nyob ib ncig ntawm 150 ° C yog cais raws li nruab nrab-Tg boards; thiab cov laug cam uas muaj Tg nyob ib ncig ntawm 170 ° C yog cais raws li high-Tg boards.

Yog hais tias muaj ntau lub sij hawm nias thaum lub sij hawm ua PCB (ntau tshaj 1 zaug), los yog muaj ntau txheej PCB (ntau tshaj 14 khaubncaws sab nraud povtseg), los yog soldering kub siab (> 230 ℃), los yog ua hauj lwm kub siab (ntau tshaj 100 ℃), los yog cov thermal stress loj (xws li yoj soldering), siab Tg daim hlau yuav tsum tau xaiv.

2. Coefficient ntawm Thermal Expansion (CTE)

Lub coefficient ntawm thermal expansion muaj feem xyuam rau kev ntseeg tau ntawm vuam thiab siv. Lub hauv paus ntsiab lus ntawm kev xaiv yog ua raws li kev nthuav dav coefficient ntawm Cu li sai tau los txo cov thermal deformation (dynamic deformation) thaum vuam).

3. Thaum tshav kub kub tsis kam

Thaum tshav kub kub kuj feem ntau txiav txim siab lub peev xwm los tiv thaiv qhov kub thiab txias ntawm soldering lub sij hawm. Feem ntau, qhov tseeb welding test yog nqa tawm nrog cov txheej txheem nruj me ntsis dua li cov vuam ib txwm. Nws tseem tuaj yeem raug xaiv raws li qhov ntsuas kev ua tau zoo xws li Td (kub ntawm 5% poob thaum lub sijhawm cua sov), T260, thiab T288 (lub sijhawm thermal tawg).