Method for fabricating a semiconductor device having a refractory metal pillar for electrical connection
First Claim
1. A method for fabricating a semiconductor device, said method comprising the steps of:
- forming a first insulation film on a first wiring layer formed on a semiconductor substrate;
forming a second insulation film on said first insulation film;
forming a third insulation film on said second insulation film;
forming a hole through said first, second and third insulation films to expose said first wiring layer at its bottom;
forming a refractory metal pillar structure by filling in said hole with a refractory metal;
forming a fourth insulation film to cover exposed surfaces of said pillar structure and said third insulation film;
selectively removing portions of said third and fourth insulation films to form an opening exposing a side and a top surface of said refractory metal pillar structure; and
filling in said opening with a conductive wiring material to form a second wiring layer to electrically connect with said refractory metal pillar.
2 Assignments
0 Petitions
Accused Products
Abstract
Disclosed is a method for fabricating a semiconductor device which prevents generation of imperfections in an aluminum alloy as an upper wiring even when part of a refractory metal pillar, which fills in a contact hole connecting lower and upper wiring layers, is exposed due to displacement of the upper wiring layer. The method comprises forming a third insulation film, a second insulation film and a second wiring layer, on a first wiring layer, forming holes which extend to the first wiring layer therethrough, forming refractory metal pillars by filling in the holes with a refractory metals, and forming a fourth insulation film. The second wiring layer is formed within a groove formed by removing the third and fourth insulation films to expose top and side surfaces of the refractory metal pillar. Even when displacement is caused between the refractory metal pillar and the second wiring layer, the reliability does not decrease, since the refractory metal pillars are covered with the fourth insulation film. The second wiring layer is preferably formed by polishing.
-
Citations
22 Claims
-
1. A method for fabricating a semiconductor device, said method comprising the steps of:
-
forming a first insulation film on a first wiring layer formed on a semiconductor substrate; forming a second insulation film on said first insulation film; forming a third insulation film on said second insulation film; forming a hole through said first, second and third insulation films to expose said first wiring layer at its bottom; forming a refractory metal pillar structure by filling in said hole with a refractory metal; forming a fourth insulation film to cover exposed surfaces of said pillar structure and said third insulation film; selectively removing portions of said third and fourth insulation films to form an opening exposing a side and a top surface of said refractory metal pillar structure; and filling in said opening with a conductive wiring material to form a second wiring layer to electrically connect with said refractory metal pillar. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
-
-
14. A method for fabricating a semiconductor device, said method comprising the steps of:
-
forming a first insulation film on a first wiring layer formed on a semiconductor substrate; forming a second insulation film to a predetermined thickness on said first insulation film; forming a hole through said first and second insulation films to expose said first wiring layer at its bottom; forming a refractory metal pillar structure by filling in said hole with a refractory metal; forming a third insulation film to cover exposed surfaces of said pillar structure and said second insulation film; selectively removing portions of said second and third insulation films to form an opening exposing a side and a top surface of said refractory metal pillar structure, wherein a height of said side of said pillar exposed is made substantially equal to said predetermined thickness by etching said second insulation film with a higher etch rate than said first insulation film so that said first insulation film is used as an etching stopper film; and filling in said opening with a conductive wiring material to form a second wiring layer to electrically connect with said refractory metal pillar. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
-
-
22. A method for fabricating a semiconductor device, said method comprising the steps of:
-
forming a first insulation film on a first wiring layer formed on a semiconductor substrate; forming a second insulation film to a predetermined thickness on said first insulation film; forming a hole through said first and second insulation films to expose said first wiring layer at its bottom; forming a refractory metal pillar structure by filling in said hole with a refractory metal; forming a third insulation film to cover exposed surfaces of said pillar structure and said second insulation film; selectively removing a portion of said third insulation film to form an opening exposing a top surface of said refractory metal pillar structure and a surface of said second insulation film adjacent to said top surface of said refractory metal pillar structure using a first etchant; selectively removing a portion of said second insulation film exposed by said first etchant to form an opening exposing a side surface of said refractory metal pillar structure using a second etchant different from said first etchant, wherein a height of said side of said pillar exposed is made substantially equal to said predetermined thickness by etching said second insulation film with a higher etch rate than said first insulation film so that said first insulation film is used as an etching stopper film; and filling in said opening with a conductive wiring material to form a second wiring layer.
-
Specification