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Hermetic sealing of silicon

  • US 4,701,424 A
  • Filed: 10/30/1986
  • Issued: 10/20/1987
  • Est. Priority Date: 10/30/1986
  • Status: Expired due to Fees
First Claim
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1. A method of forming a hermetic seal between a first silicon wafer and a second silicon wafer including the steps of:

  • forming opposing troughs in each of said two silicon wafers;

    forming an isolation layer suitable for forming a barrier between silicon and metal during heating;

    forming a diffusion barrier suitable for limiting diffusion of gold;

    forming a tub of polysilicon in the cavity lined by the diffusion barrier;

    forming a gold strip on one of the polysilicon tubs;

    positioning the two silicon wafers adjacent each other so that the gold strip on one polysilicon tub aligns with the polysilicon tub of the other wafer; and

    heating the adjacent silicon wafers in a thermal gradient so as to form a silicon gold eutectic which migrates to the diffusion barrier of the silicon wafer which do not have gold film on the polysilicon tub.

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