Passive shield for CVD wafer processing which provides frontside edge exclusion and prevents backside depositions
US5851299A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 25, 1994 |
| Grant date | Dec 22, 1998 |
| Priority date | — |
| Expiry date | Mar 25, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C16/4585
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
An improved apparatus for CVD processing is described wherein a wafer mounted on a vertically movable susceptor beneath a gas outlet or showerhead is raised into contact with a shield ring which normally rests on a ring support in the chamber. The shield ring engages the frontside edge of the wafer, lifting the shield ring off its support, when the susceptor and the wafer are raised to a deposition position in the chamber. The shield ring, by engaging the frontside edge of the wafer, shields the edge of the top surface of the wafer, as well as the end edge and the backside of the wafer, during the deposition. Matching tapered edges, respectively, on the susceptor and the shield ring permit alignment of the shield ring with respect to the susceptor, and alignment of the wafer to the susceptor and the shield ring. Alignment means are also disclosed to circularly align the shield ring to its support in the chamber. Multi-unit shield rings permit the use of wider shield rings and prevent cracking of the shield ring due to thermal stresses caused by temperature differences near and away from the wafer during processing. These shield rings may also have tapered edges to ensure alignment …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.