Breeta Sengupta

Scheduling Tests for 3D Stacked Chips under Power Constraints

This paper addresses Test Application Time (TAT)reduction for core-based 3D Stacked ICs (SICs). Applyingtraditional test scheduling methods used for non-stacked chiptesting where the same test schedule is applied both at wafer testand at final test to SICs, leads to unnecessarily high TAT. This isbecause the final test of 3D-SICs includes the testing of all thestacked chips. A key challenge in 3D-SIC testing is to reduce TATby co-optimizing the wafer test and the final test while meetingpower constraints. We consider a system of chips with coresequipped with dedicated Built-In-Self-Test (BIST)-engines andpropose a test scheduling approach to reduce TAT while meetingthe power constraints. Depending on the test schedule, the controllines that are required for BIST can be shared among severalBIST engines. This is taken into account in the test schedulingapproach and experiments show significant savings in TAT. (Less)