A new test/diagnosis/rework model for use in technical cost modeling of electronic systems assembly

Abstract

This paper presents a test/diagnosis/rework analysis model for use in technical cost modeling of electronic assemblies. The approach includes a model of test operations characterized by fault coverage, false positives, and defects introduced in test, in addition to rework and diagnosis operations that have variable success rates and their own defect introduction mechanisms. The model can accommodate an arbitrary number of rework attempts on any given assembly and can be used to optimize the fault coverage and rework investment during system tradeoff analyses. The model's implementation allows all inputs to the model to be represented as probability distributions thereby accommodating inevitable uncertainties in input data present during tradeoff activities and uses Monte Carlo methods to determine model outputs.

Parameter Estimation for a Model with Both Imperfect Test and Repair

“…Dislis et al [5] have several papers in investigating the dynamics of test cost optimization, while in [6] a comprehensive model with imperfect testing and retesting is described. Trichy et al [7] allow false positives as well as allowing defects to be introduced before and after test. Our model [1,2], illustrated with the simplest test and repair network in Fig.…”

Optimization of Test/Diagnosis/Rework Location(s) and Characteristics in Electronic System Assembly

“…The solution strategy developed in this section is not specific to any particular TDR model formulation, however, we have used the model from Trichy et al [7] (see Section 3). The solution strategy outlined in the section also has several limitations: 1) it assumes the cost of actually placing a TDR is the same independent of the location (this is not necessarily true); 2) the strategy assumes that if rework is performed, it is performed immediately after a test; 3) the methodology does not directly exploit the fact that changing the manufacturing process steps (and possibly the product topology) could reduce test cost further (i.e., the methodology optimizes a given process flow only); and 4) the test operation modeled only accounts for a single fault type as opposed to a portfolio of fault types.…”

Optimization of test/diagnosis/rework location(s) and characteristics in electronic systems assembly using real-coded genetic algorithms

“…in a general process flow and how they relate to the resulting cost and yield, a comprehensive model was developed by Trichy et al [7]. This model provides a detailed formulation of the characteristic parameters for a single TDR operation.…”

“…2 shows the content of the model and detailed formulations are given in [7]. 1 1 Note, several typographical errors should be corrected in [7]: In (2) and (3), the maximum of the summation should be n-1 instead of n, and (4a) can be used for either definition of f p with Fig. 2.…”

“…After all the optimum fault coverages are generated by the GAs optimization, the results can be verified using the Trichy et al model discussed in [7] and Section 3 by assessing a full range of fault coverages for a specific incoming die yield and comparing the GAs optimum fault coverage value with those calculated values. Fig.…”