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In-Line Reliability Limited Yield

IP.com Disclosure Number: IPCOM000062478D
Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Effron, MS: AUTHOR

Abstract

The method described here is an extension of the concept described in U.S. Patent 3,751,647, which emphasizes photo limited yield (PLY) modeling. A reliability test limited yield (RTLY) is created, utilizing electrical test data taken at progressive stages of device processing and packaging, to project failure probability. Thus, a semiconductor manufacturing line control is established to attain high reliability required of very large-scale integration (VLSI) circuits. VLSI product is normally tested on wafers ("Post-metallization probe"), at the device level, deck level of assembly, post burn-in, and final module test. RTLY data is taken at each of the normal test levels. For RTLY determination, the product is tested outside of the normal test window in increasing increments of voltage on any of several voltage parameters.

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In-Line Reliability Limited Yield

The method described here is an extension of the concept described in U.S. Patent 3,751,647, which emphasizes photo limited yield (PLY) modeling. A reliability test limited yield (RTLY) is created, utilizing electrical test data taken at progressive stages of device processing and packaging, to project failure probability. Thus, a semiconductor manufacturing line control is established to attain high reliability required of very large-scale integration (VLSI) circuits. VLSI product is normally tested on wafers ("Post-metallization probe"), at the device level, deck level of assembly, post burn-in, and final module test. RTLY data is taken at each of the normal test levels. For RTLY determination, the product is tested outside of the normal test window in increasing increments of voltage on any of several voltage parameters. Failure types and patterns are recorded for each increment of test voltages. By so doing, test data as a function of the voltage increments can be used to project potential field fail rates, for each fail type. Projection of RTLY per type of failure is calculated by standard reliability forecasting techniques. Once the modeling has been checked and adjusted to fit end product reliability test results, utilization of RTLY data provides measurement of progress toward reliability goals. Determination of largest detractors to RTLY, both in terms of defect type and location of greatest occurrence within the manufac...