Methods for forming microlithographic masks that compensate for proximity effects
US6087046A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 15, 1998 |
| Grant date | Jul 11, 2000 |
| Priority date | — |
| Expiry date | Apr 15, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/36
- WIPO fieldMicro-structural and nano-technology
- WIPO sectorChemistry
Abstract
Methods are disclosed for forming microlithography (photolithography or charged-particle-beam projection lithography) masks exhibiting reduced proximity effects. A first exposure is made, using an electron beam at a first exposure intensity level, on a mask substrate. The first exposure is made on region(s) of the mask substrate corresponding to the desired basic feature(s) of the mask pattern. A second exposure is made, using, the electron beam at a second exposure intensity level, at "secondary exposure regions" that at least partially reside within the basic feature(s). Thus, portions of the basic features receive a cumulative electron exposure that is greater than other portions of the basic features. Such increased cumulative exposure causes an alteration of the profile of the subject basic feature sufficient to cause the resulting modified basic feature to exhibit a reduced proximity effect. The secondary exposure areas are preferably square and/or rectangular, extending along one or more edges of the subject basic feature, and can overlap or not overlap the corresponding edge(s) of the basic feature. The width and exposure intensity levels for the secondary exposure areas ar…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.