US 5,514,625 AGranted

Method of forming a wiring layer

AssigneeKabushiki Kaisha Toshiba

InventorHitoshi Tsuji

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Abstract

A novolak-based resist layer is formed on an interlayer insulating film, and that portion of the resist layer which is left as a resist mask for a wiring layer groove is formed by the first exposure and the heat treatment in an ammonia atmosphere. Thus, the solution rate of that portion of the resist layer is rendered low with regard to the alkali developing solution. Subsequently, the resist layer is exposed and developed in a regular manner to form a resist mask for defining a contact hole. With the obtained resist pattern used as a mask, the interlayer insulating film is etched to a depth which equals to a length of a contact hole in the depth direction formed at a later step. After that, with use of the resist pattern whose solution rate with respect to the alkali developing solution has been made low as a mask, the wiring layer groove is formed. With the method, a mask resist pattern used for defining a contact hole can be formed in a predetermined region, even if the exposure of the resist layer is displaced from the position where it should have been. Further, no step portion is created between the contact hole and the wiring groove.

Claims14

Dependent claims

A method of forming a wiring layer comprising the steps of:

forming a first wiring layer on a substrate layer;
forming an interlayer insulating film on the first wiring layer;
forming a resist layer on the interlayer insulating film;
exposing the resist layer to light, using a first mask having a pattern corresponding to a groove formed later in the interlayer insulating film to provide a low solution rate in that portion of the resist layer which is other than a portion corresponding to the groove;
exposing the resist layer to light, using a second mask having a pattern corresponding to a contact hole in the groove and formed later in the interlayer insulating film and developing the resist layer using a developing solution, to form a first resist pattern corresponding to the pattern of the second mask;
etching a selected portion of the interlayer insulating film to a first depth, using the first resist pattern;
exposing the resist layer to light and developing the resist layer using a developing solution, to form a second resist pattern corresponding to the pattern of the first mask;
etching a selected portion of the interlayer insulating film to a second depth, using the second resist pattern, to form the contact hole and the groove in the interlayer insulating film;
removing the second resist pattern;
and
forming a second wiring layer by filling the contact hole and the groove with a wiring material.

8 more elements

Dependencies are inferred from the claim text.