Projection exposure method, projection exposure apparatus, laser radiation source and bandwidth narrowing module for a laser radiation source
US8896816B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 12, 2011 |
| Grant date | Nov 25, 2014 |
| Priority date | — |
| Expiry date | May 10, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S3/225
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In a projection exposure method for the exposure of a radiation-sensitive substrate arranged in the region of an image surface of a projection objective with at least one image of a pattern of a mask arranged in the region of an object surface of the projection objective, laser radiation having a spectral intensity distribution I(ω) dependent on the angular frequency ω is used. The laser radiation is characterized by an aberration parameter α in accordance with:and a coherence time τ in accordance with:The laser radiation is introduced into an illumination system for generating an illumination radiation directed onto the mask, and the pattern is imaged onto the substrate with the aid of a projection objective. The spectral intensity distribution is set so that ατ2≦0.3. The influence of temporally varying speckles on image generation can be reduced by comparison with conventional methods, without simultaneously increasing the influence of chromatic aberrations on image generation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.