Comparison of Two Temporary Carriers for Test and Burn-In of Memory Die

Abstract

Die-Level-Bum-In (DLBI) approaches based on temporary bare die carriers are emerging in the industry as a practical, near-term solution for the production of known-good-die requiring bum-in. The goal for carrier development for test and burn-in is a cost-effective, bare die contact and. fixturing approach for both peripheral and array contacts as well as wire bond and bumped die. We are using both an FSRAM and a DRAM die to evaluate two bare die carrier technologies. The carriers differ in the type of bump used to contact the die ("piercing" vs. "burnishing" contacts) and in the design of the fixture used to hold the die in contact with the carrier. Mechanical evaluations include measurements of critical carrier features such as bump height, die alignment guide and aluminum bond pad damage caused by the carrier contacts. Contact integrity and the impact of bare-die test and burn-in on subsequent wirebond strength is being evaluated. Functionality of both carrier designs has been demonstrated by successful memory burn-in and at-speed test for both die types.