Browse Prior Art Database

Direct Readout Particle Detection System

IP.com Disclosure Number: IPCOM000051980D
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Abraitis, A: AUTHOR [+2]

Abstract

Conventionally, in order to quickly find particle contamination on blan wafers, a photograph was taken and then the light points would be counted on an image analyzer. Described is a new method to by-pass the photograph using a special 4-way illuminator system which produces uniform lighting. The light points of the particles on a semiconductor wafer are detected directly with a special plumbicon camera which integrates the image and then scans. The outputs of the particles are counted, and sized, and the location given on an output printer in less than one minute.

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Direct Readout Particle Detection System

Conventionally, in order to quickly find particle contamination on blan wafers, a photograph was taken and then the light points would be counted on an image analyzer. Described is a new method to by-pass the photograph using a special 4-way illuminator system which produces uniform lighting. The light points of the particles on a semiconductor wafer are detected directly with a special plumbicon camera which integrates the image and then scans. The outputs of the particles are counted, and sized, and the location given on an output printer in less than one minute.

As the drawing indicates, the technique comprehends illuminating a blank wafer with four high intensity lamps. The even lighting pattern which is produced on the wafer is a dark field illumination. The particles scatter light, and the background contrast is black. The high contrast now allows the special plumbicon camera to integrate these small light points. An electronic processor can now count, measure, and map these points. The display can produce histograms and distributions immediately. This new system eliminates the need to take photographs which then must be counted on an image analyzer.

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