Wafer fabrication process
View Patent ↗A wafer fabrication process with removal of haze formation from a pellicalized photomask surface is provided. The wafer fabrication process includes pre-print wafer processing, wafer print processing using at least one photomask having a pellicle, photomask clean processing, wafer print processing using the photomask, and post-print wafer processing. The photomask clean processing step includes directing a laser through the pellicle towards an inorganic particle disposed on the photomask to remove the particle from the photomask by thermal decomposition.
1. A wafer fabrication process, comprising:
pre-print wafer processing;
wafer print processing using at least one photomask having a pellicle;
photomask clean processing, including:
directing a laser through the pellicle toward an inorganic particle disposed on the photomask to remove the particle from the photomask by thermal decomposition, and
directing an airflow onto the pellicle to reduce thermal build up in the pellicle;
wafer print processing using the photomask; and
post-print wafer processing.
2. The method of claim 1 , wherein the photomask includes a substrate and at least one thin film layer disposed thereon.
3. The method of claim 2 , wherein the thin film layer is patterned and includes void areas under which respective portions of the substrate are exposed.
4. The method of claim 1 , further comprising maintaining a temperature of the photomask below a threshold temperature to prevent damage thereto.
5. The method of claim 1 , wherein the photomask includes a contaminating layer disposed thereon.
6. The method of claim 5 , wherein the contaminating layer is a haze layer.
7. The method of claim 6 , wherein the haze layer is an ammonium sulfate haze layer.
8. The method of claim 5 , wherein the contaminating layer is inorganic.
9. The method of claim 1 , wherein a substrate of the photomask has an absorption spectrum that does not include a local maximum at about 7 μm.
10. The method of claim 1 , wherein the particle has an absorption spectrum with a local maximum at about 3 μm.
11. The method of claim 1 , wherein the particle has an absorption spectrum with a local maximum at about 7 μm.
12. The method of claim 11 , wherein the laser has a wavelength that is substantially the same as the local maximum of the particle absorption spectrum.