Methodology for repeatable post etch CD in a production tool

US6858361B2 · kind B2 · utility

Inventors

• David Mui · Fremont, US
• Hiroki Sasano · Sunnyvale, US
• Wei Liu · Espoo, FI

Key dates

• Filing date: Sep 9, 2002
• Grant date: Feb 22, 2005
• Expiry date: Feb 5, 2023

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L22/20
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

A method and apparatus for processing a semiconductor wafer is provided for reducing dimensional variation by feeding forward information relating to photoresist mask CD and profile to adjust the next process the inspected wafer will undergo (e.g., a photoresist trim process). After the processing step, dimensions of a structure formed by the process, such as the CD of a gate formed by the process, are measured, and this information is fed back to the process tool to adjust the process for the next wafer to further reduce dimensional variation. By taking into account photoresist CD and profile variation when choosing a resist trim recipe, post-etch CD is decoupled from pre-etch CD and profile. With automatic compensation for pre-etch CD, a very tight distribution of post-etch CD is achieved. In certain embodiments, the CD and profile measurements, trim, etch processing and post-etch cleaning are performed at a single module in a controlled environment. All of the transfer and processing steps performed by the module are performed in a clean environment, thereby increasing yield by avoiding exposing the wafer to the atmosphere and possible contamination between steps.