Multiple photoresist layer process using selective hardening
US4859573A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 21, 1987 |
| Grant date | Aug 22, 1989 |
| Priority date | — |
| Expiry date | Aug 21, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/095
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A process for selectively hardening a surface layer of a polymeric photoresist to make such surface layer opaque and insoluble in photoresist carrier solvents, where such selectivity is coextensive with the polymeric/monomeric pattern created in the photoresist. Representative hardening processes include controlled exposure to certain gas plasmas, ion bombardment, or irradiation by ultraviolet radiation of chosen wavelength range. The selectively hardened polymeric regions act as a barrier to the carrier solvent in which the polymer film is laid down and to the developer subsequently employed to remove the monomeric regions. The hardened polymeric regions further exhibit an actinic radiation barrier property preventing radiation depolymerization. In one form the process may be used in a two-layer photoresist structure, where the pinhole-covering thicker second layer is laid down and exposed before developing the monomeric regions of the thinner first layer. Thereafter, a single development operation serves to remove the monomeric regions of both layers. The actinic barrier prevents depolymerization of the monomeric regions of the first layer during the second exposure. In a second …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.