Browse Prior Art Database

Attainment of Either a Narrow or Wide Oxygen Precipitate Free Zone in Silicon Wafers

IP.com Disclosure Number: IPCOM000050463D
Original Publication Date: 1982-Nov-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Bischoff, BK: AUTHOR [+3]

Abstract

This article describes a method to obtain controlled narrow oxygen precipitate free zones in silicon wafer processing.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 81% of the total text.

Page 1 of 2

Attainment of Either a Narrow or Wide Oxygen Precipitate Free Zone in Silicon Wafers

This article describes a method to obtain controlled narrow oxygen precipitate free zones in silicon wafer processing.

The initial high temperature required in the process places a constraint on the narrow end of a precipitate free zone to above eight microns. In order to attain free zones below this level, and not lose the benefits of the high temperature anneal, the treatment is performed on the wafer prior to polishing.

It should be noted that all wafer processing is normally done on a finished polished product surface. The wafer is submitted for polishing which removes the oxygen-depleted area near the surface from the prior heat treatment. One can now choose the proper time and temperature to give a particular oxygen precipitate free zone width.

Zone widths as narrow as two microns have been achieved using the following processing steps:

1. Solution treat wafers at 1150'C to polishing, following the time- temperature relationship shown in Fig. 1. This insures that all oxygen is in solution, and allows for donor annihilation and the gettering of metal impurities.

2. Polish wafers to product specifications. This step removes the oxygen depleted region that would normally limit the precipitate free zone that one could obtain.

3. Out-diffuse the oxygen below the surface to form the desired precipitate free zone. The process is similar to step number one, but time and temperature...