Rapid coating of wafers
US8906452B1 · kind B1 · utility
Inventor
Key dates
| Filing date | May 24, 2012 |
| Grant date | Dec 9, 2014 |
| Priority date | — |
| Expiry date | May 24, 2032 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/162
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An improved technique achieves a uniform photoresist film on a wafer by controlling the volatility of the solvent in a photoresist solution during the bake process step. Because film formation takes place in the bake rather than the spin steps of the process, the improved technique involves using less viscous and therefore less costly and easier to use resists to cast relatively thick photoresist films. Such control is achieved in an enclosed chamber into which a carrier gas is introduced; the carrier gas mixes with gaseous solvent to create a saturating atmosphere in which the rate of evaporation of solvent decreases. This enables the heating of the wafer without the reduction of solvent in the film so that the photoresist can self-level. When the film has self-leveled, the solvent is then baked off as usual.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.