Methods and apparatus for collecting process characterization data after first failure in a group of tested devices

Abstract

Collecting process characterization data local to a failed integrated circuit (IC), includes providing a wafer having ICs, each IC having contact terminals, the wafer having process characterization test sites distributed across it such that at least one process characterization test site is adjacent each IC; selecting two or more ICs for simultaneous testing; for each of those ICs, coupling two or more contact terminals of the selected IC, and a corresponding two or more contact terminals of an associated test site to corresponding input terminals of a multiplexer, each multiplexer having an output terminal and a select control input terminal, the multiplexer operable to selectively provide an electrical pathway between either an IC contact terminal or a test site contact terminal and the multiplexer output terminal; coupling the output terminal of each multiplexer to a tester channel; operating the multiplexer so that its output terminal is coupled to the IC contact terminal; simultaneously testing two or more ICs; detecting a failure of at least one of the selected ICs prior to completion of testing the remaining ICs simultaneously being tested; subsequent to detecting the failure, operating the multiplexer so that its output terminal is coupled to the test site contact terminal; and collecting process characterization data prior to completion of testing the remaining ICs.