Published Articles / Papers

How to Extract Defect Densities from Distributions

Alain R. Comeau, IEEE Transactions on Semiconductor Manufacturing, Vol. 3, No. 2, May 1990.

Abstract

A technique is presented for representing a defect density, such as might be found on an integrated circuit. Distributions are a powerful tool for presenting defect distributions for test structures and are convenient for yield analysis and modeling. How the concept of distribution can be extended to give more information on the defects is shown. The power of this approach derives from its invariability to test stricture geometry, which enables direct comparison of data from different structures. It is explained how and why defect distributions measured on test structures can be related to those of other structures, i.e. integrated circuits. The mathematics are simple and lead to a defect density which can be expressed in units of defects per geometric factor per independent variable.

Modeling the Bending of Probes

Alain R. Comeau and Normand Nadeau, IEEE Transactions on Semiconductor Manufacturing, Vol. 4, No. 2, May 1991.

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Abstract

An analytical model for the bending of probes used in the semiconductor industry is presented. It is shown that tip sliding distance is twice as large as was previously believed. This difference is shown to be caused by the beam curvature, which increases the angle between the tip and the vertical and pushes the tip forward. The model uses the probe shape and the material elastic properties to estimate the beam curvature. Tip sliding distance, force, and tip angle variance are calculated as functions of beam dimensions and overdrive. The model is in agreement with sliding distance measured by scanning electron microscopy.

Improvement to Bulk Oxygen Precipitate Density

Alain R. Comeau, Journal of Electrochemical Society, Vol. 139, No. 5, May 1992

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Abstract

The addition of a ramped nucleation cycle, just after an initial oxidation, is shown to greatly increase the precipitation of interstitial oxygen during simulated processing on N/N+ antimony doped epitaxial wafers. When used with fully processed wafers, the ramped nucleation improves internal gettering. Oxygen precipitate density and bulk stacking fault density achieved are about a factor of 100 higher when using ramped nucleation. These results indicate that N/N+ antimony doped epitaxial wafers have an intrinsic gettering capability as good as that of lightly doped material when using an activation cycle (initial oxidation) and subsequent ramped nucleation. A method for calculating bulk stacking fault density is presented. It is shown that, at high concentration (above 107 cm−3), the square of the bulk stacking fault length is inversely proportional to their density. This finding indicates that the growth of bulk stacking faults is limited by the supply of interstitial silicon generated in the bulk during oxygen precipitate growth.

An Automated Electrical Defect Identification and Location Method for CMOS Processessing a Specially Designed Test Chip

Alain R. Comeau, and Jacques Laneuville, IEEE Transactions on Semiconductor Manufacturing, Vol. 5, No. 3, August 1992.

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Abstract

A test chip (named Yieldchip) was designed, simulated, fabricated, and tested on a 3- mu m process. The layout of the Yieldchip’s cells enables the test program to electrically locate and identify active faults, thereby automating the, classification of defects. The Yieldchip can detect more than one defect per circuit in most circumstances. The algorithm can identify the 21 simple defects of the cells and can be used as an expert system to extend this list. Unidentified detectable faults are flagged at all times and located if possible.

Mixed-Signal Yield Improvement, the Human Factor

Alain R. Comeau, Semiconductor Fabtech, 12^th edition, 2000

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Abstract

When I started to write this article, I put down on three pages the outline of the subjects I wanted to discuss. Interestingly enough, the outline started with a long list of knowledge and skills one should have to be as efficient as possible in mixed-signal field improvement. Only at the third page did I consider defining what mixed-signal products even were! I guess this set the tone. In this article, we will mostly discuss people skills (sorry, techies!). In a high-tech world where marketing is oriented towards equipment, machines, devices, and product performance, etc., we will talk about people. But first, in order to set up the proper background, let me start at the end.

A Systems-First Approach to High-Voltage IC Design

How SimpleChips designs high-voltage silicon for systems that must perform reliably over decades

Samir Jaber , Wevolver.com, January 2026

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Business Tai Chi: Values-First Model for Operating a Deep-Tech Company

Samir Jaber , Wevolver.com, March 2026

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Abstract

Echoing Tai Chi’s balance over force, SimpleChips founder Alain R. Comeau redefines success beyond revenue metrics, emphasizing three pillars: financial sustainability for independent engineering focus; alignment with core values (integrity, innovation, quality, service) for purposeful decisions; and continuous learning to compound expertise from project iterations.

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