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Thin film process monitoring techniques using acoustic waves

  • US 5,271,274 A
  • Filed: 08/14/1991
  • Issued: 12/21/1993
  • Est. Priority Date: 08/14/1991
  • Status: Expired due to Term
First Claim
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1. A system for measuring thickness of at least one film on a substrate, such constituting a composite unit, said film and substrate having an interface, said system comprising:

  • means including a buffer rod having an end shaped to make Hertzian contact with said composite unit for propagating a high frequency acoustic wave through said composite unit, said acoustic wave generating reflected echo waves at the interfaces between the buffer rod and composite, between the composite and air, and between the film and substrate;

    means for receiving said echowaves and generating output signals; and

    means for processing said output signals to give a film thickness value.

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