Bonding Issues Related to Probe Needle Mark Size on Aluminum Bond Pads

摘要

This paper describes the reliability issues related to damage Aluminum bond pads in a microchip. The damaged bond pads are caused due to heavy probe needle marks and indentation during Electrical Wafer Sort (EWS) process due to the probe tips. Figure 1 shows the indentation marks in the bond pad which may result in a bonding issues of wire bond or bumps to the bond pads. Multiple probe marks, due to reworks, will generate heavy probe marks on the bond pad during EWS testing. If the probe marks are not controlled, there is a reliability concern for bump process. It is necessary to control the manufacturability of wafer sort process to sustain probe needle mark size with an area of less than 25% of the aluminum bond area. The probe mark size requirement was due to new technologies with reduced bond pad size and assembly site bonding issues of bumps to the bond pads. The probe needle mark size process was developed for Teradyne Catalyst, A585, and A565 mixed signal testers in conjunction with Electroglas 4090 micro probers. The process can be converted to additional automated test equipment platforms, including parametric test.