Browse Prior Art Database

WAFER SCRUBBER TEST METHOD

IP.com Disclosure Number: IPCOM000005944D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2001-Nov-19
Document File: 1 page(s) / 41K

Publishing Venue

Motorola

Related People

Robert Governal: AUTHOR

Abstract

The failure of a wafer scrubber to remove surface contamination from a wafer can cause catastrophic contamina- tion effects such as reduced yields. The test disclosed below measures the effectiveness of a wafer scrubber in remov- ing contamination and can serve as an early warning system to let an operator know that a wafer scrubber is failing. In the present test, clean wafers are evaluated using a particle detector such as a Tencor 4500 to obtain background counts. The wafers are then inoculated with particles from a clean room swab in an alternating pattern on the wafer. The particles are again counted on the particle detector and data histograms are plotted. The wafers are then cycled through the wafer scrubber and the particles are then recounted and plotted. A removal rate can be calculated from the difference in the two counts divided by the "after contamination" counts.

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Technical Developments October 1990

WAFER SCRUBBER TEST METHOD

by Robert Governal

   The failure of a wafer scrubber to remove surface contamination from a wafer can cause catastrophic contamina- tion effects such as reduced yields. The test disclosed below measures the effectiveness of a wafer scrubber in remov- ing contamination and can serve as an early warning system to let an operator know that a wafer scrubber is failing. In the present test, clean wafers are evaluated using a particle detector such as a Tencor 4500 to obtain background counts. The wafers are then inoculated with particles from a clean room swab in an alternating pattern on the wafer. The particles are again counted on the particle detector and data histograms are plotted. The wafers are then cycled through the wafer scrubber and the particles are then recounted and plotted. A removal rate can be calculated from the difference in the two counts divided by the "after contamination" counts.

   The method is highly beneficial in its ability to show contamination patterns on a particle detection system both before and after scrubbing. The test may be applied to any wafer scrubber to measure its effectiveness at removing particles. The technique may be used a general preventative tool to reduce the number of wafers lost due to scrubber failure and also to test the operation and efficiency of a wafer scrubber.

0 Motorola, Inc. 1990

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