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Method for film thickness endpoint control

  • US 5,131,752 A
  • Filed: 06/28/1990
  • Issued: 07/21/1992
  • Est. Priority Date: 06/28/1990
  • Status: Expired due to Fees
First Claim
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1. A method of control of thickness of a film on a substrate comprising the steps of:

  • positioning the substrate in a chamber,controlling environment in said chamber to change thickness of a film on the substrate,employing an ellipsometer to measure delta and psi coordinates of said film,determining delta and psi coordinates of an endpoint of desired thickness,defining a control line through said endpoint in accordance with the equation A (De)+B (Pe)+C=0 wherein A, B, and C are constants of an unbounded line passing through the endpoint, and De and Pe are the delta and psi coordinates of said endpoint.reading measured delta and psi coordinates to define measurement points as thickness of said film changes,determining the relation between said control line and said measurement points, andterminating change in said film thickness in response to said relation.

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