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Method for forming interconnection structure

DC CAFC
  • US 6,197,696 B1
  • Filed: 03/23/1999
  • Issued: 03/06/2001
  • Est. Priority Date: 03/26/1998
  • Status: Expired due to Term
First Claim
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1. A method for forming an interconnection structure, comprising the steps of:

  • a) forming a first insulating film over lower-level metal interconnects;

    b) forming a second insulating film, having a different composition than that of the first insulating film, over the first insulating film;

    c) forming a third insulating film, having a different composition than that of the second insulating film, over the second insulating film;

    d) forming a thin film over the third insulating film;

    e) forming a first resist pattern on the thin film, the first resist pattern having openings for forming wiring grooves;

    f) etching the thin film using the first resist pattern as a mask, thereby forming a mask pattern out of the thin film to have the openings for forming wiring grooves;

    g) forming a second resist pattern on the third insulating film, the second resist pattern having openings for forming contact holes;

    h) dry-etching the third insulating film under such conditions that the third insulating film and the first and second resist patterns are etched at a relatively high rate and that the second insulating film is etched at a relatively low rate, thereby patterning the third insulating film to have the openings for forming contact holes and removing the first and second resist patterns either entirely or partially with respective lower parts thereof left;

    i) dry-etching the second insulating film using the patterned third insulating film as a mask under such conditions that the second insulating film is etched at a relatively high rate and that the first and third insulating films are etched at a relatively low rate, thereby patterning the second insulating film to have the openings for forming contact holes;

    j) dry-etching the third and first insulating films using the mask pattern and the patterned second insulating film as respective masks under such conditions that the first and third insulating films are etched at a relatively high rate and that the mask pattern and the second insulating film are etched at a relatively low rate, thereby forming wiring grooves and contact holes in the third and first insulating films, respectively; and

    k) filling in the wiring grooves and the contact holes with a metal film, thereby forming upper-level metal interconnects and contacts connecting the lower- and upper-level metal interconnects together.

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