Modulation of peripheral critical dimension on photomask with differential electron beam dose
US6210843A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 22, 1999 |
| Grant date | Apr 3, 2001 |
| Priority date | — |
| Expiry date | Nov 22, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/3175
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method is described comprising depositing a layer of resist on a mask substrate having transparent and opaque layers. The resist layer is then exposed to radiation. The radiation is patterned to produce features within an active device area and a moat surrounding the active device area. The radiation is also controlled to have a differential increased incident energy in the moat area of the mask compared to the active device area. Specifically, the exposure dose applied to the moat is greater than that normally required to completely remove the resist during the developing stage. The magnitude of the additional exposure dose is empirically derived and is based upon such factors as the type of resist and the thickness of the resist.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.