Degassing method and apparatus
US6182376A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 10, 1997 |
| Grant date | Feb 6, 2001 |
| Priority date | — |
| Expiry date | Jul 10, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/67109
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An apparatus and method is provided for capturing, heating and degassing a wafer without using moving parts and without exposing the wafer to external stress. A degassing chamber is backfilled with a dry gas that improves wafer heating ramp rates and wafer heating uniformity. The backfilled gas efficiently conducts heat at relatively low pressures. Thus the degassing chamber may be evacuated via a cryo-pump without the need for an intermediate rough pumping step. Further, because the wafer is heated primarily by conduction, wafer temperatures are easily and precisely controlled independent of layers previously deposited on the wafer. Frontside heating elements such as heat generators and/or heat reflectors are provided that further improve wafer heating ramp rates and wafer heating uniformity by directing heat toward the front surface of the wafer. Preferably as heat radiates from the wafer it is reflected back to the wafer by a frontside reflector. The improved wafer heat uniformity provides more uniform desorption of contaminants which are then entrained by the dry gas and pumped from the degassing chamber. An isolation valve such as a slit valve provides a highly reliable and in…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.