Dynamic feedback electrostatic wafer chuck

US5812361A · kind A · utility

Assignee

• Lam Research Corporation · US

Inventors

• Phillip Jones · Fremont, US
• Seyed Jafar Jafarian-Tehrani · Fremont, US
• Boris Atlas · Wiesbaden, DE
• David R. Liu · Lexington, US
• Ken Tokunaga · Fremont, US
• Ching-Hwa Chen · Milpitas, US

Key dates

• Filing date: Mar 29, 1996
• Grant date: Sep 22, 1998
• Expiry date: Mar 29, 2016

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T279/23
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

An electrostatic chuck system having an electrostatic chuck for securely holding a wafer on a surface of the electrostatic chuck. The electrostatic chuck system comprises a wafer bias sensor coupled to a first portion of the electrostatic chuck for sensing an alternating current signal at the first portion. The wafer bias sensor outputs, responsive to the alternating current signal, a direct current voltage level representative of a direct current bias level of the wafer. The electrostatic chuck system further comprises a variable electrostatic chuck power supply coupled to the wafer bias sensor. The variable electrostatic chuck power supply provides a first potential level to the first portion of the electrostatic chuck. The first potential level is modified, responsive to the direct current voltage level, to substantially maintain a first predefined potential difference between the first portion of the electrostatic chuck and a first region of the wafer overlaying the first portion irrespective of a magnitude of the direct current bias level of the wafer.