X-ray lithography using holographic images
US5612986A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 22, 1995 |
| Grant date | Mar 18, 1997 |
| Priority date | — |
| Expiry date | Sep 22, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03H2001/0094
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Methods for forming X-ray images having 0.25 .mu.m minimum line widths on X-ray sensitive material are presented. A holgraphic image of a desired circuit pattern is projected onto a wafer or other image-receiving substrate to allow recording of the desired image in photoresist material. In one embodiment, the method uses on-axis transmission and provides a high flux X-ray source having modest monochromaticity and coherence requirements. A layer of light-sensitive photoresist material on a wafer with a selected surface is provided to receive the image(s). The hologram has variable optical thickness and variable associated optical phase angle and amplitude attenuation for transmission of the X-rays. A second embodiment uses off-axis holography. The wafer receives the holographic image by grazing incidence reflection from a hologram printed on a flat metal or other highly reflecting surface or substrate. In this second embodiment, an X-ray beam with a high degree of monochromaticity and spatial coherence is required.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.