US 5,858,877 A · Self-aligned process for making contacts to silicon substrates during the manufacture of integrated circuits therein

Abstract

A process for forming vertical contacts in the manufacture of integrated circuits, and devices so manufactured. The process eliminates the need for precise mask alignment and allows the etch of the contact hole to be controlled independent of the etch of the interconnect trough. The process includes the steps of: forming an insulating layer on the surface of a substrate; forming an etch stop layer on the surface of the insulating layer; forming an opening in the etch stop layer; etching to a first depth through the opening in the etch stop layer and into the insulating layer to form an interconnect trough; forming a photoresist mask on the surface of the etch stop layer and in the trough; and continuing to etch through the insulating layer until reaching the surface of the substrate to form a contact hole. The above process may be repeated one or more times during the formation of multi-level metal integrated circuits.

Claims24

Dependent claims

A process for forming electrical contacts for integrated circuits, comprising the steps of:

a. forming a first layer on a substrate;
b. forming an etch stop layer consisting of an inorganic compound on the first layer, the etch stop layer being selectively etchable with respect to the first layer;
c. forming an opening in the etch stop layer at a desired location of a trough;
d. etching the first layer through the opening to a first depth to form a trough;
e. forming a mask over the trough and the etch stop layer;
f. selectively removing the mask to expose portions of the first layer within the trough at a desired location of a contact hole;
g. etching the exposed portions of the first layer to a second depth to form a contact hole;
and
h. removing the mask.

6 more elements

Dependencies are inferred from the claim text.

Self-aligned process for making contacts to silicon substrates during the manufacture of integrated circuits therein

Life of this patent

Self-aligned process for making contacts to silicon substrates during the manufacture of integrated circuits therein

Life of this patent

Abstract

Claims24