Complete, contactless I/O testing reaching the boundary in minimizing digital IC testing cost

Abstract

Embedded test of memory and random logic can enable very low cost ATE to test large, high speed ICs because high quality at-speed tests can be generated onchip. However, it is also necessary to test the DC and AC parameters of the input/output (I/O) circuitry. This paper describes how most I/O pin characteristics can be tested cost-effectively with a variety of novel techniques that exploit the 1149.1 and 1149.4 test standards. The techniques measure VOL/IOL, VOH/IOH, VIH, and VIL at DC, perform at-speed I/O wrap, and test on-chip power rail impedance, all via minimum pin-count (MPC) access. The 1149.4 bus is also suitable, of course, for testing mixed-signal functions. The paper then discusses costs and benefits of MPC testing of high pin-count ICs on a low cost tester to show that testing costs can be reduced to insignificance.