US 5,912,188 A
Method of forming a contact hole in an interlevel dielectric layer using dual etch stopsGeneral
US 5,912,188 A
Method of forming a contact hole in an interlevel dielectric layer using dual etch stops
Tech Center:
1700 Chemical and Materials Engineering
Examiner:
William Powell
Art Unit:
1765 Organic Chemistry, Polymers, Compositions
Inventors:
MARK I GARDNER; DANIEL KADOSH; FREDERICK N HAUSE
Assignee:
Priority:
08/04/97
Filed:
08/04/97
Granted:
06/15/99
Expiration:
08/04/17
Abstract
A method of forming a contact hole in an interlevel dielectric layer using dual etch stops includes the steps of providing a semiconductor substrate, forming a gate over the substrate, forming a source/drain region in the substrate, providing a source/drain contact electrically coupled to the source/drain region, forming an interlevel dielectric layer that includes first, second and third dielectric layers over the source/drain contact, forming an etch mask over the interlevel dielectric layer, applying a first etch which is highly selective of the first dielectric layer with respect to the second dielectric layer through an opening in the etch mask using the second dielectric layer as an etch stop, thereby forming a first hole in the first dielectric layer that extends to the second dielectric layer without extending to the third dielectric layer, applying a second etch which is highly selective of the second dielectric layer with respect to the third dielectric layer through the opening in the etch mask using the third dielectric layer as an etch stop, thereby forming a second hole in the second dielectric layer that extends to the third dielectric layer without extending to the source/drain contact, and applying a third etch which is highly selective of the third dielectric layer with respect to the source/drain contact through the opening in the etch mask, thereby forming a third hole in the third dielectric layer that extends to the source/drain contact, wherein the first, second and third holes in combination provide the contact hole. In this manner, the contact hole is formed in the interlevel dielectric without any appreciable gouging of the underlying materials.