Protruded contact and insertion of inter-layer-dielectric material to match damascene hardmask to improve undercut for low-k interconnects

US7601607B2 · kind B2 · utility

Assignee

• Chartered Semiconductor Manufacturing LTD · SG

Inventors

• Wuping Liu · Singapore, SG
• Raymond Joy · Singapore, SG
• Beichao Zhang · Singapore, SG
• Liang-Choo Hsia · Singapore, SG
• Boon Meng Seah · Singapore, SG
• Shyam Sundar Pal · Sherghati, IN

Key dates

• Filing date: May 15, 2006
• Grant date: Oct 13, 2009
• Expiry date: Apr 26, 2027

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/76814
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

An embodiment of the invention shows a process to form a damascene opening preferably without hardmask overhang or dielectric layer undercut/void. The low-k dielectric material can be sandwiched in two hardmask films to form the dielectric film through which an interconnect opening is etched. A first example embodiment comprises the following. We form a lower interconnect and an insulating layer over a semiconductor structure. We form a first hardmask a dielectric layer, and a second hardmask layer, over the lower interconnect and insulating layer. We etch a first interconnect opening in the first hardmask, the dielectric layer and the second hardmask layer. Lastly, we form an interconnect in the first interconnect opening.