The effects of postbake treatment on a pure matte Snplated copper leadframes under high temperature and humidity conditions were investigated. The samples were divided into two categories: those without postbake treatment (WOPB) and those with postbake treatment (WPB), which exposed at 125□ for 1 hour. The X-ray intensity decreased through all crystal orientations after the postbake treatment. For matte Sn-plated Cu leadframes stored at 55°C/85%RH for 1800 hours, nodule-shaped whiskers were observed on samples WOPB, while none were on samples WPB. The WPB samples have a regular layer of IMCs approximately 27% narrower than the WOPB samples. The IMCs had two distinct layers divided into large-grains and small-grains. The large-grain layers located on the Sn side grew before the small-grain layers. The IMCs in the WOPB and WPB samples were identified as Cu6Sn5 and η-Cu6.26Sn5. IMC precipitates were also observed at the grain boundaries and some IMC precipitates were embedded at the Sn matrix. No Cu3Sn or Kirkendall voids were observed at the interface between the Sn and Cu.
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机译：研究了在高温和湿度条件下对纯无光泽络合铜引线框架进行的后烘烤处理的影响。将样品分为两类：没有退出治疗（WOPB）的那些，与后烘焙处理（WPB）的那些，其暴露在125℃下1小时。 X射线强度在后烘干处理后通过所有晶体取向降低。对于储存在55℃/ 85％RH的遮罩SN镀Cu引线镜1800小时，在样品WOPB上观察到结节形晶须，而NONE在样品WPB上。 WPB样品具有比WOPB样品窄的IMC的常规层。 IMC有两个不同的层，分为大颗粒和小粒。位于SN侧的大谷物层在小晶粒层之前增长。 WOPB和WPB样品中的IMC被鉴定为CU 6 SN 5 和η-CU 6.26 SN 5 。在晶界，也观察到IMC沉淀物，并且在Sn基质中嵌入一些IMC沉淀物。在Sn和Cu之间的界面中观察到Cu 3 SN或KIRKENDALL空隙。
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