Methods of forming channels and vias in insulating layers

  • US 5,173,442 A
  • Filed: 03/24/1992
  • Issued: 12/22/1992
  • Est. Priority Date: 07/23/1990
  • Status: Expired due to Term
First Claim
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1. A method for forming a channel and a via in an insulating layer, said channel being a horizontally disposed in the top surface of and partially through the thickness of the insulating layer and said via being adjacent to the channel and vertically disposed and completely through the thickness of the insulating layer, said method comprising the steps of:

  • covering the insulating layer with a hard mask having an opening to expose the channel and the via wherein the hard mask is non-erodible by an etch;

    covering the hard mask with a soft mask having an opening to expose the via but covering the channel wherein the soft mask is erodible by the etch;

    applying the etch to at least partially remove the insulating layer where the via is exposed until the soft mask is eroded;

    applying the etch after the soft mask is eroded to remove the insulating layer where the channel is exposed and to remove any of the insulating layer remaining where the via is exposed so that the channel and the via are formed; and

    removing the hard mask from the insulating layer.

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