Browse Prior Art Database

Techniques for Achieving Silicon Wafer Countouring Produce High Precision Ring Shaped Wafers

IP.com Disclosure Number: IPCOM000123270D
Original Publication Date: 1998-Aug-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Cazcarra, V: AUTHOR

Abstract

In order to improve the automatic handling of large diameter wafers (300mm and more), to get a well defined active surface particularly advantageous for S0I structures and to present a natural barrier against contamination, a new shape of the wafer rim has been designed (see Fig. 1). For more details, please refer to the Research Disclosure Bulletin, March 1998, p. 301. Two processes to produce those high precision ring shape wafers are proposed below.

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Techniques for Achieving Silicon Wafer Countouring Produce High Precision
Ring Shaped Wafers

   In order to improve the automatic handling of large
diameter wafers (300mm and more), to get a well defined active
surface particularly advantageous for S0I structures and to present a
natural barrier against contamination, a new shape of the wafer rim
has been designed (see Fig. 1).  For more details, please refer to
the Research Disclosure Bulletin, March 1998, p. 301.  Two processes
to produce those high precision ring shape wafers are proposed below.

   The first technique is close to what is usually done
today in manufacturing and takes place after the lapping (or sawing)
operation.  The cutting tool, shown in Fig. 2, is adapted in order to
have at the same time the rounded rim and the ring.  Afterwards, the
wafers are polished normally.

   The other technique is based upon a specific ingot
shapping.  Today thanks to the high precision Wire Saw Technology we
can define a process where regularly spaced trenches are made around
the grinded ingot.

   Such trenches of a depth of around 420 microns cab be
made using thick sawing wires (350 microns) with a simultaneously
rotating crystal.

   Later, the damaged zones will be removed by chemical
etching of the ingot.  This should lead to trenches of around 450
microns width as indicated in Fig. 3 and rounded edges.

   Such etched ingot will be accurately sawed (Fig. 3),
using the classical wires of the Wire Saw Tech...