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Technique for Eliminating Backside Contamination During Wafer Processing/ Characterization

IP.com Disclosure Number: IPCOM000053108D
Original Publication Date: 1981-Aug-01
Included in the Prior Art Database: 2005-Feb-12
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Conner, TF: AUTHOR [+3]

Abstract

To eliminate contamination introduced by the wafer chuck or holder during wafer processing and characterization, this article proposes the use of a silicon wafer as a barrier between the wafer chuck and the device wafer.

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Technique for Eliminating Backside Contamination During Wafer Processing/ Characterization

To eliminate contamination introduced by the wafer chuck or holder during wafer processing and characterization, this article proposes the use of a silicon wafer as a barrier between the wafer chuck and the device wafer.

The chuck illustrated schematically above is primarily usable as a stable base for testing device wafers. The device wafer 1 is held to the chuck 2 through the use of vacuum which increases friction between the chuck surface and the wafer. Normally, this would increase the chances of metallic contamination from the chuck surface 3. Elimination of this contamination is achieved through the use of a base silicon wafer 4 as a barrier between the wafer chuck and the device wafer.

To provide a vacuum path to the (new) surface 5, holes 6 are opened in wafer 4 connecting to the chuck an internal vacuum system 7, indicated in broken lines. Preferably, these holes are ultrasonically bored, but one could equally mask the wafer and use a chemical etch to achieve the same result. Subsequently, using a conductive silver epoxy 8 for good electrical contact, wafer 4 is adhered to the wafer chuck 2. If no electrical contact is required, one could oxidize wafer 4 before attaching it to the wafer chuck 2. Wafer 4 now acts as a barrier effectively preventing backside contamination which otherwise could have come from the wafer chuck 2.

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