Holding apparatus for holding an article such as a semiconductor wafer
US5324012A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 6, 1992 |
| Grant date | Jun 28, 1994 |
| Priority date | — |
| Expiry date | Jul 6, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/6838
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A holder which cleanly holds an article such as a semiconductor wafer and which is high in rigidity, light in weight, high in dimensional stability and excellent in dust resistance. The wafer holder includes a vacuum holding surface formed with a plurality of concentric or helical annular projections and annular vacuum holding grooves which are arranged at a given pitch. A plurality of vacuum holes for vacuum holding purposes are formed in the respective annular grooves so as to be arranged radially and each of the vacuum holes is subjected to pressure reduction by a vacuum source through the interior of the holder, thereby correcting the flatness of a wafer to conform with the upper surfaces of the annular projections. At least the portions of the holder which contact with the wafer (preferably the holder on the whole) are made of a sintered ceramic containing covalent bond-type conductive material such as a TiC-containing sintered Al.sub.2 O.sub.3 so that the contact portions exhibit conductivity and also less pores are present in the surface, thereby practically preventing the occurrence and deposition of fine particles.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.