Modeling and evaluating the quality assurance of multichip module systems /

In this dissertation, the quality assurance of multichip

Bibliographic Details
Main Author:	Park, Nohpill
Format:	Thesis Book
Language:	English
Published:	[Place of publication not identified] : [publisher not identified] ; 1997.
Subjects:	Major computer science.
Online Access:	http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=739891311&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD

Description
Summary:	In this dissertation, the quality assurance of multichip module (MCM) systems for testing at assembly is studied using new analytical models and evaluation approaches. Quality reduction during assembly of MCM systems under uneven fault- coverage and imperfect diagnosis is proposed using a Markov- based model. Uneven fault-coverage and imperfect diagnosis occur due to the different procurement and quality levels of manufacturers of these chips. The proposed Markov-chain based model is employed to compute quality by relating different measures, such as known-good-yield, test fault- coverage and diagnosis. Unlike previous works in which quality is computed as function of yield and even (equally- like) fault-coverage, this method computes quality accurately by including the effect of diagnosis as well as the uneveness in fault-coverage at the assembly phase of MCMs to fully characterize the manufacturing process. Parametric results show that an imperfect diagnosis has a more pronounced impact on the quality of MCM systems than an uneven fault-coverage. The effects of a repair process on the defect level of MCM systems is also analyzed. The proposed model, which employs a Markov-chain model, calculates the defect level as function of various figures, such as the probability of successfully repairing a fault (referred to as repairability), the probability of damaging the system and the maximum allowed number of repair cycles. It is shown that due to the repair process the overall defect-level decreases as the MCM yield increases up to the maximum number of repair cycles, thus achieving an increase in repairability. Stratified testing is proposed for an improvement in quality level (QL) and cost-effectiveness in the presence of uneven known-good-yield (KGY) for MCMs consisting of different sets (or strata) of chips. For comparison purposes, exhaustive testing (ET), random testing (RT) and random stratified testing (RST) are also evaluated. Given the strata, KGY and the sample size of the chips under test, the proposed LYSFT (lowest yield- stratum first-testing) approach allocates and tests the sampled chips in a greedy (first) fashion, while RT and RST select the chip (for RT) and the stratum (for RST) randomly. A Markov-chain model is developed to analyze these testing approaches. It is shown the LYSFT dramatically outperforms RT and RST for improving the QL. A considerable reduction in tests can be achieved by the LYSFT at a very small loss in QL compared with ET.
Item Description:	Vita. "Major Subject: Computer Science".
Physical Description:	xii, 108 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc.
Bibliography:	Includes bibliographical references: pages 91-97.