Abstract: A method and apparata for correcting for pulse width timing error during testing of an integrated circuit are described. The method includes storing in a memory, associated with a selected terminal of an integrated circuit, event timing data pertaining to testing of the integrated circuit. Functional data is provided, pertaining to the testing, and it is determined if the functional data causes a state transition in the integrated circuit, the state transition causing a pulse. If a pulse is created, then the event timing data is adjusted, thereby to produce pulse width adjusted event timing. A test signal is then applied to the selected terminal of the integrated circuit, the test signal including pulse width adjusted event timing. A test program first loads scrambler and sequencer memories with a code representing event timing data and event type data for a number of events that are to occur during a test vector, as specified by the user.

Abstract: A method and apparatus for calibrating tester timing accuracy during testing of integrated circuits. An ATE tester measures itself through reference blocks that have the same relevant dimensions as the integrated circuits to be tested. The number of reference blocks required is equal to the number of signal terminals on an integrated circuit to be tested being subject to timing calibration. A signal trace electrically connects a different signal terminal to a common reference terminal on each reference block. Each signal trace used should be closely matched both physically and electrically to the other signal traces used in the set of reference blocks, so that the electrical path length associated with each trace is nearly identical. To perform the timing calibration, the reference blocks may be mounted on a single fixture one at a time, or using multi-site fixtures, multiple reference blocks may be used in parallel.