Qhov kev xaiv ntawm PCB txheej txheej tshuab rau SMT soldering hauv SMT kev ua haujlwm feem ntau yog nyob ntawm hom kev sib dhos zaum kawg, thiab cov txheej txheem kho saum npoo yuav cuam tshuam rau kev tsim khoom, sib dhos thiab siv zaum kawg ntawm PCB. Cov nram qab no luv luv qhia txog kev xaiv ntawm PCB solderability nto txheej.

Thaum xaiv cov txheej txheej solderable ntawm PCB hauv thaj ua haujlwm, xaiv cov khoom siv sib xyaw thiab cov khoom siv yuav tsum raug txiav txim siab.

1. Solder alloy muaj pes tsawg leeg

Lub compatibility ntawm PCB ncoo txheej thiab solder alloy yog qhov tseem ceeb ntawm kev xaiv PCB solderable nto txheej (plating). Qhov no ncaj qha cuam tshuam rau kev sib txuas thiab kev ntseeg siab ntawm cov pob qij txha ntawm ob sab ntawm lub ncoo. Piv txwv li, Sn-Pb kub cua leveling yuav tsum raug xaiv rau Sn-pb alloy, thiab cua kub theem rau hlau tsis muaj hlau lead lossis hlau tsis muaj hlau lead alloy yuav tsum tau xaiv rau cov hlau tsis muaj hlau lead.

2. Kev ntseeg tau

Cov khoom uas yuav tsum tau muaj kev ntseeg siab yuav tsum xub xaiv tib lub cua kub leveling raws li cov solder alloy, uas yog qhov zoo tshaj plaws kev xaiv rau compatibility. Tsis tas li ntawd, cov khoom zoo Ni-Au (ENIG) kuj tseem tuaj yeem txiav txim siab, vim tias qhov kev sib txuas ntawm lub zog ntawm lub interface alloy Ni3Sn4 ntawm Sn thiab Ni yog qhov ruaj khov tshaj plaws. Yog tias siv ENIG, Ni txheej yuav tsum tau tswj kom> 3 µm (5 mus rau 7 µm), thiab Au txheej yuav tsum yog ≤ 1 µm (0.05 txog 0.15 µm), thiab cov kev cai solderability yuav tsum tau muab tso rau tom khw.

3. Cov txheej txheem tsim tawm

Thaum xaiv PCB solderable nto txheej (plating) txheej, qhov sib xws ntawm PCB ncoo txheej txheej thiab cov txheej txheem tsim khoom yuav tsum raug txiav txim siab. Cov cua kub theem (HASL) muaj qhov zoo weldability, tuaj yeem siv rau ob tog rov qab vuam, thiab tuaj yeem tiv taus ntau yam vuam. Txawm li cas los xij, txij li qhov saum npoo ntawm lub ncoo tsis tiaj tus, nws tsis haum rau qhov nqaim. OSP thiab immersion tin (I-Sn) yog qhov tsim nyog rau kev sib dhos ib leeg thiab cov txheej txheem ib zaug.