Effect of Conventional and Granular Capillaries Usage on the Bondability, Reliability, and Manufacturability of Gold Wedge Bonds

Abstract

The evaluation of the manufacturability, bondability, and reliability performances of the granular capillary is required to produce high-quality wire bonds. In this paper, two different types of wire bonding capillaries, namely, granular and conventional capillaries, were used for the gold (Au) wire bonding process. The wire pulling test was performed on the Au wire bonds created by both types of capillaries right after the wire bonding process and after the Au wire bonds were gone through accelerated tests of high-temperature storage and temperature cycling tests. It is noted that wire pull strengths were increased with the usage of the granular capillary compared to that of the conventional capillary for all five samples due to the occurrence of intimate bond between Au wedge bonds and bond pads. The increase of yield and the occurrence of consistence with one type of the failure mode for the Au wedge bonds that used granular capillary are due to the increment of scrubbing surface area between Au wire bonds and bond pads. The reduction of wire bonder stoppage with the usage of the granular capillary is due to the reduction of the short tail failure mode occurrence. This can be seen through the increment of the average yield percentage. It is observed that the granular capillary has the highest number of touchdowns or lifetimes compared to that of the conventional capillary. It is also found that the created wire bonds that used granular capillary have good bondability and reliability. These findings are based on the evaluation of the bonding interface thickness and distribution.