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Calibration Method for Testers

IP.com Disclosure Number: IPCOM000108008D
Original Publication Date: 1992-Apr-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 49K

Publishing Venue

IBM

Related People

Hivert, C: AUTHOR [+3]

Abstract

The purpose of this article is to describe a tester calibration method that uses the product to be tested as a reference. This corrects the majority of errors generated by probing.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 65% of the total text.

Calibration Method for Testers

       The purpose of this article is to describe a tester
calibration method that uses the product to be tested as a reference.
This corrects the majority of errors generated by probing.

      Major difficulty for fast VLSI test is the poor test system
accuracy to measure critical product timing: access, set-up and hold
time. Typical test system accuracy is in the  500 ps range, which
is not enough to test parameters that are close to 3 ns. The major
reason for this lack of accuracy is the impossibility to calibrate
delays in the transmission lines up to chip terminations because
these terminations are not accessible.

      A possible solution to this problem is to use product to make
calibration. This is possible if product input and output have
latches that can be triggered by other chip inputs. Propagation
delays in the product between inputs and between outputs are very
close to each other (< 30 ps). To calibrate inputs, the trigger time
delay is incremented, and the time for which the trigger is loaded
with the input value can be measured for each input. For each input a
delay is programmed from these measurements so that all inputs are
present at the same time at latch input in the product. To calibrate
outputs, the time between trigger input and data present at chip
output is measured, and these values are loaded in the tester to move
the strobe so that all outputs are simultaneous. This calibration
procedure takes care...