冷卻速率對銲錫凸塊之微硬度和接觸電阻的影響及無電鍍鎳對鋁墊打線接合的影響

Abstract

本論文分為兩部份,第一部份探討銲錫凸塊在流銲過程中之冷卻速率對其 微硬度及接觸電阻的影響。實驗結果發現在較高之冷卻速率下,可得較小 的微硬度值及接觸電阻。而較低的冷卻速率則造成高的微硬度值及接觸電 阻。此可歸因於介金屬化合物之產生及金原子之擴散效應。第二部份討論 在鋁墊上無電鍍鎳對打線接合的影響,試片接合強度試驗,測試結果均遠高 於合格值。無電鍍鎳後再施行浸鍍金之試片,則呈較差之接合性。 The thesis is divided into two parts. In part one, the effects of cooling rate on the microhardness and contact resistance of solder bumps during reflow were investigated. Wettability on a Ti/Ni/Au substrate using bump metallurgy was also investigated. The top Au film was found to have good wettability with solder. A high cooling rate of the solder bumps during reflow resulted in the low microhardness and contact resistance. A low cooling rate of the solder bumps during reflow produced more Ni- Sn intermetallic compounds and led to mechanical failure by fracture and to the degradation of the electrical properties of the solder bumps. The effects of electroless Ni plating on Al pads for wirebonding were discussed in part two. The bond strength test of specimens were up to the specificaions. However, the bondability of specimens were immersion dipped Au after electroless Ni plating is very poor.