Browse Prior Art Database

Impurity Profiling

IP.com Disclosure Number: IPCOM000076236D
Original Publication Date: 1972-Feb-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Jung, G: AUTHOR [+2]

Abstract

This apparatus and method is adapted for the automation of impurity profiling of semiconductors. In the process the wafer is oxidized, the oxide dissolved, and the resultant solution analyzed.

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Impurity Profiling

This apparatus and method is adapted for the automation of impurity profiling of semiconductors. In the process the wafer is oxidized, the oxide dissolved, and the resultant solution analyzed.

In order to measure an impurity profile in semiconductors by 1) neutron activation, 2) incremental sheet resistance, and 3) chemical profiling technique, it is necessary to oxidize portions of the wafer and analyze the dissolved oxide by techniques 1 and 3, and the wafer for technique 2. This oxidation is usually done anodically. The oxidation and subsequent steps for profiling when done manually is a very time consuming process.

In this apparatus, as shown in Fig. A, a wafer 10 is mounted at approximately a 20 degrees angle in test fixture 12. Included with 12 is a four point probe 14 for measuring incremental sheet resistance, a light source 16, and detector 18 to measure oxide thickness. Anodizing solution is added through inlet 20 and a layer of oxide is formed. The layer thickness of the oxide is controlled by time or anodizing voltage. After the sample has been anodized, the oxide thickness is measured and the layer is dissolved by a solution introduced through inlet 20. The resulting solution is drained through outlet 22 by valve 24 into a container
26. As shown in B, container 26 is mounted on conveyor 28 where it is transported from beneath fixture 12 to a testing station, where the sample can be analyzed by a spectrophotometric device 30. As ind...