Browse Prior Art Database

Substrate Screening Process

IP.com Disclosure Number: IPCOM000041662D
Original Publication Date: 1984-Feb-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Ahlgren, DC: AUTHOR [+4]

Abstract

This article concerns a screening method for selecting silicon wafers likely to show low oxygen precipitation. Wafers of this type have been shown capable of producing devices of higher yield. The method features a series of heating steps which are designed to simulate the manufacturing environment to select preferential wafer lots. Oxygen precipitated beyond certain limits is detrimental to subsequent device yields. Present screening methods unfortunately fail to simulate the oxygen precipitation kinetics which arise during device processing and accordingly fail as effective wafer screens. In accordance with the method of this article, it has been found that with a series of heat cycles repeated for an appropriate number of times it is possible to simulate the product cycle effect on the substrate.

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Substrate Screening Process

This article concerns a screening method for selecting silicon wafers likely to show low oxygen precipitation. Wafers of this type have been shown capable of producing devices of higher yield. The method features a series of heating steps which are designed to simulate the manufacturing environment to select preferential wafer lots. Oxygen precipitated beyond certain limits is detrimental to subsequent device yields. Present screening methods unfortunately fail to simulate the oxygen precipitation kinetics which arise during device processing and accordingly fail as effective wafer screens. In accordance with the method of this article, it has been found that with a series of heat cycles repeated for an appropriate number of times it is possible to simulate the product cycle effect on the substrate. It has also been found that the resulting oxygen precipitation as determined by Fourier Transform Infrared Spectroscopy (FTIR) can be effectively predicted. The heat cycle of this method is derived by averaging each section of the heat cycle of each process step for time and temperature and then repeating the cycle the appropriate number of times to equal the total processing time (Fig.
1). The times, temperature and cycling are all necessary to reproduce the proper production cycle. One main advantage is that any product cycle (bipolar or FET) can be simulated this way. To apply this approach as a screening method, the total number of heat...