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Eliminating Process Cassette Upright Support Shadowing During Batch Electroless Plating

IP.com Disclosure Number: IPCOM000132316D
Publication Date: 2005-Dec-07
Document File: 2 page(s) / 188K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that modifies the process cassette holder, using a recessed wafer holder, to eliminate the shadowing effects of the two support uprights. Benefits include preventing unwanted wafer movement and improving the uniformity of cleaned wafers.

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Eliminating Process Cassette Upright Support Shadowing During Batch Electroless Plating

Disclosed is a method that modifies the process cassette holder, using a recessed wafer holder, to eliminate the shadowing effects of the two support uprights. Benefits include preventing unwanted wafer movement and improving the uniformity of cleaned wafers.

Background

The current process cassette design uses four uprights that run the entire vertical length of the cassette (see Figure 1). Two are used for mechanical stability, and due to their locations do not mask the chemical dispense to the wafer surface from the spray posts (i.e. contribute to thin electroless plating). The other uprights are located at the outer area of the process cassette (i.e. furthest away from the center of rotation) and are used primarily to prevent the wafers from being slung out of the process cassette during rotation. This second set of support uprights shadows the area of the wafer directly in back of the support uprights.

Currently, this problem is not solved by any existing batch spray hardware. Single wafer immersion processes are not subject to shadowing effects, due to the absence of the supports posts.

General Description

Figure 2 shows the disclosed method’s process cassette redesign, enabling the elimination of the two large support uprights while still addressing the rotational forces applied to the wafers. The disclosed method uses a recessed, horseshoe-shaped wafer holder with a wire vertical...