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Tool for Wafer Aligning Before Chemical Etching of the Wafer Rim

IP.com Disclosure Number: IPCOM000047208D
Original Publication Date: 1983-Oct-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Novak, B: AUTHOR

Abstract

It is well known that the polishing step causes excessive friability of the edge of semiconductor wafers. A very successful solution to this problem is to chamfer the wafer edges. This operation has been described in the literature [1]. After chamfering, however, the wafer edge is damaged, which, in turn, results in scratches on the surface of the wafers during polishing caused by the particles of silicon which are removed from the edge. This edge damage produces various defects during semiconductor processing which greatly affect the final yields. In order to lower edge damage, the wafer rims are chemically etched, as previously described [2]. Thus far, wafers have been manually aligned. The wafers are piled with their notches and flats aligned.

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Tool for Wafer Aligning Before Chemical Etching of the Wafer Rim

It is well known that the polishing step causes excessive friability of the edge of semiconductor wafers. A very successful solution to this problem is to chamfer the wafer edges. This operation has been described in the literature [1]. After chamfering, however, the wafer edge is damaged, which, in turn, results in scratches on the surface of the wafers during polishing caused by the particles of silicon which are removed from the edge. This edge damage produces various defects during semiconductor processing which greatly affect the final yields. In order to lower edge damage, the wafer rims are chemically etched, as previously described [2]. Thus far, wafers have been manually aligned. The wafers are piled with their notches and flats aligned. Unfortunately, with this method, some wafers will have their rims out of specification, due to inevitable misalignment of the notches. In addition, this manual alignment operation is time consuming, imprecise and relatively difficult. A special tool was built to give a reproducible and perfect etching of the wafer rim. The principle basically consists of piling up the wafers and arranging them on an axle (Fig. 1), the axle diameter being thinner than the notch length.

When the axle is rotated by a motor, the wafers also rotate until they stop; this occurs when the axle lodges in the notch. The wafers are then aligned. Next, they are tightened using the hand...