Study of silver alloy wire decapsulation methods for failure analysis

Silver alloy wires with the advantage of low cost, good thermal conductivity and electrical conductivity have been adopted in packaging industry [1, 2]. For plastic encapsulated microelectronics (PEMs) conventional wet decapsulation method is widely used and is implemented by using individual acid or mix acid. However silver alloy dissolves easily in acid. In this study, we present an automatic decapping approach using chemical acid mixture with KI+I2. This method is effective for silver alloy wire packages. There is no observable attack or corrosion on wires or bonding pads, and the wires are very uniform with no evidence of thinning or pitting.