Removable pellicle for lithographic mask protection and handling
US6492067B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 3, 1999 |
| Grant date | Dec 10, 2002 |
| Priority date | — |
| Expiry date | Dec 3, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70983
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A removable pellicle for a lithographic mask that provides active and robust particle protection, and which utilizes a traditional pellicle and two deployments of thermophoretic protection to keep particles off the mask. The removable pellicle is removably attached via a retaining structure to the mask substrate by magnetic attraction with either contacting or non-contacting magnetic capture mechanisms. The pellicle retaining structural is composed of an anchor piece secured to the mask substrate and a frame member containing a pellicle. The anchor piece and the frame member are in removable contact or non-contact by the magnetic capture or latching mechanism. In one embodiment, the frame member is retained in a floating (non-contact) relation to the anchor piece by magnetic levitation. The frame member and the anchor piece are provided with thermophoretic fins which are interdigitated to prevent particles from reaching the patterned area of the mask. Also, the anchor piece and mask are maintained at a higher temperature than the frame member and pellicle which also prevents particles from reaching the patterned mask area by thermophoresis. The pellicle can be positioned over the m…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.