Variable step height control of lithographic patterning through transmitted light intensity variation
US5821013A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 13, 1996 |
| Grant date | Oct 13, 1998 |
| Priority date | — |
| Expiry date | Dec 13, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/50
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method and apparatus for forming layers of photo-sensitive materials in different thicknesses. A mask including a first area that substantially blocks light transmission and a second area having optical characteristics, which partially blocks light transmission is employed. Light is projected through the mask onto a layer of photo-sensitive material. The first area substantially blocks the light from passing through and leaves portions of the photo-sensitive material unexposed. The secondary area reduces the intensity of light passing through the mask and projected onto other portions of the photo-sensitive material. After developing the photo-sensitive material, at least two thicknesses of photo-sensitive material results. The second area may include a number of sections that vary from each other in optical characteristics such that the intensity of the light projected onto the layer of photo-sensitive material through the second area varies in steps or continuously.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.