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SILICON WAFER THINNING AND DICING ROUND OR NON ORTHOGONAL DIE USING DRY ETCHING

IP.com Disclosure Number: IPCOM000007267D
Original Publication Date: 1994-Oct-01
Included in the Prior Art Database: 2002-Mar-08
Document File: 1 page(s) / 81K

Publishing Venue

Motorola

Related People

David Shumate: AUTHOR [+4]

Abstract

This paper describes a novel method of Silicon wafer thinning and etching round or non orthogo- nal shapes using a dry etch system. There are sev- eral types of dry etch systems on the market today. The most efficient systems are the microwave radi- cal generators. In addition this type ofsystem imparts little or no radiation damage to the material being etched.

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Technical Developments Volume 23 October 1994

SILICON WAFER THINNING AND DICING ROUND OR NON ORTHOGONAL DIE USING DRY ETCHING

by David Shumate, Hiep Le, Garty Vick and Bill Wasmer

  This paper describes a novel method of Silicon wafer thinning and etching round or non orthogo- nal shapes using a dry etch system. There are sev- eral types of dry etch systems on the market today. The most efficient systems are the microwave radi- cal generators. In addition this type ofsystem imparts little or no radiation damage to the material being etched.

  Current methods ofwafer thinning in the semi- conductor industry uses a lapping, grinding or wet chemical etching. A typical process is to remove about ,002 to ,010 inches from the back surface ofa wafer. Generally speaking the lapping and grinding method imparts a lot of stress and damage into the back surface of a wafer. This stress is removed with a wet chemical etch. Another method of thinning uses a wet chemistry and etches the back surface of the wafer. A new method for thinning Silicon wafers is to use a microwave Fl radical generator. These systems can generate etch rates of up to 0.0008 inch per minute at 100 degrees C. In 10 minutes of etch- ing about 0.010 inches of material can be removed. The Fl radicals impart no radiation damage on the wafer surface.

  One method of mounting a wafer in a radical generator is to put the wafer on a A1203 (Alumi- num oxide) tray. The A1203 is inert to the Fl radi- cals. The tray would also protect the front surface of the wafer. If this was not sufficient then a layer of photoresist or wax could be applied to the front sur- face and increase protection to the front surface of the wafer. An example of the A1203 tray and wafer are illustrated in Figure 1. I is the wafer and II is the tray. Note the surface of t...