Method of reworking structures incorporating low-k dielectric materials

US7008803B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Terence L. Kane · Beacon, US
• Chung-Ping Eng · Hopewell Junction, US
• Brett H. Engel · Fishkill, US
• Barry Ginsberg · Poughkeepsie, US
• Dermott MacPherson · Pleasant Valley, US
• John Charles Petrus · Potsdam, US

Key dates

• Filing date: Oct 24, 2002
• Grant date: Mar 7, 2006
• Expiry date: Aug 15, 2023

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L2924/0002
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Methods of etching a semiconductor structure using ion milling with a variable-position endpoint detector to unlayer multiple interconnect layers, including low-k dielectric films. The ion milling process is controlled for each material type to maintain a planar surface with minimal damage to the exposed materials. In so doing, an ion beam mills a first layer and detects an endpoint thereof using an optical detector positioned within the ion beam adjacent the first layer to expose a second layer of low-k dielectric film. Once the low-k dielectric film is exposed, a portion of the low-k dielectric film may be removed to provide spaces therein, which are backfilled with a material and polished to remove the backfill material and a layer of the multiple interconnect metal layers. Still further, the exposed low-k dielectric film may then be removed, and the exposed metal vias polished.