Browse Prior Art Database

Means to Automate the Creation of VLSI A/C Wafer Test Patterns from Hardware A/C Tests

IP.com Disclosure Number: IPCOM000103076D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 47K

Publishing Venue

IBM

Related People

Billings, RV: AUTHOR [+4]

Abstract

In many cases it is very difficult and time consuming to create critical path or A/C patterns for sorting VLSI chips. An innovative approach is to first use the chip's built-in hardware self-test function to identify its long delay paths. This method identifies the machine state the cycle before an A/C timing failure occurs. A process has been developed to automatically convert this machine state information into test fixture patterns to sort the speed of wafers or modules being fabricated. Once automated, this process aids in the development of additional wafer patterns from empirical hardware results from a wider process or speed sample of modules.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Means to Automate the Creation of VLSI A/C Wafer Test Patterns from Hardware A/C Tests

      In many cases it is very difficult and time consuming to create
critical path or A/C patterns for sorting VLSI chips. An innovative
approach is to first use the chip's built-in hardware self-test
function to identify its long delay paths.  This method identifies
the machine state the cycle before an A/C timing failure occurs.  A
process has been developed to automatically convert this machine
state information into test fixture patterns to sort the speed of
wafers or modules being fabricated.  Once automated, this process
aids in the development of additional wafer patterns from empirical
hardware results from a wider process or speed sample of modules.
With a better library of test cases created to identify the
functional speeds of the newly fabricated wafers, less high speed
module yield is lost from an excessive guardband, which would
normally be required to guarantee system functionality.

                            (Image Omitted)

      Disclosed anonymously.