The interfacial reaction of Ag-xPd wire bonding on Al pad under various testing conditions

• Main Authors: Wei-HsiangHuang, 黃蔚翔
• Other Authors: kwang-Lung Lin
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/10491905604810275587

碩士 === 國立成功大學 === 材料科學及工程學系 === 104 === The industry is trying to replace part of gold and copper wire bond with silver wires. Ag-Pd alloy wire was reported as a potential candidate because of its high reliability. This study investigated the interfacial reaction of Ag-xPd wire bonding on Al pad under various testing conditions. Aging, pressure cook test (PCT), temperature cycling test (TCT) and un-biased accelerated and humidity stress test (u-HAST) were applied on As-bonded AgxPd(1~6%) wire bonding samples to study the interfacial reaction. The SEM images of wire bond under different test conditions were analyzed. The results indicated that the growth of the intermetallic compound (IMC) was enhanced when the content of Pd is more than 3.5%. The composition of IMC was analyzed by SEM-EDX. It shows that the contents of Al in IMC decrease when the Pd content of alloy wire increases. An increase in the content of Pd in alloy wire leads to promote the formation of (Ag,Pd)2Al rather than (Ag,Pd)3Al2. After PCT test, the corrosion behavior occurred at the interface and Ag-rich IMC (Ag,Pd)3Al formed above the Al-pad. Under TCT test, the (Ag,Pd)3Al2 formed at the interface. The (Ag,Pd)3Al2 exhibits larger difference the coefficient of thermal expansion (CTE) with alloy wire. It tends to induce the crack formation during TCT test. The increasing Pd content inhibits the corrosion of the wire bond under u-HAST test.