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Method for contactless real-time in-situ monitoring of a chemical etching process

  • US 5,480,511 A
  • Filed: 06/30/1994
  • Issued: 01/02/1996
  • Est. Priority Date: 06/30/1994
  • Status: Expired due to Fees
First Claim
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1. A contactless method for in-situ chemical etch monitoring of an etching process during etching of a workpiece with a wet chemical etchant, said method comprising the steps of:

  • a) providing at least two toroidal windings disposed in the wet chemical etchant to be proximate to but not in contact with the workpiece, each of said at least two toroidal windings having a principal axis through a respective hollow center portion thereof, wherein one of said at least two toroidal windings comprises a generator winding and wherein another one of said at least two toroidal windings comprises a detector winding; and

    b) monitoring an electrical characteristic of the workpiece and the wet chemical etchant between said at least two toroidal windings, wherein a prescribed change in the electrical characteristic is indicative of a prescribed condition of the etching process.

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