Apparatus and method for indirect surface cleaning
View Patent ↗A photomask includes at least one feature disposed thereon. The at least one feature has an associated design location, where a distance between a location of the at least one feature and the associated design location defines a positional error of the at least one feature. A method for improving a performance characteristic of the photomask includes directing electromagnetic radiation toward the photomask, the electromagnetic radiation having a wavelength that substantially coincides with a high absorption coefficient of the photomask; generating a thermal energy increase in the photomask through incidence of the electromagnetic radiation thereon; and decreasing the positional error as a result of the generating the thermal energy increase in the photomask.
1. A method for improving a performance characteristic of a photomask, the photomask having at least one feature disposed thereon, the at least one feature having an associated design location, a distance between a location of the at least one feature and the associated design location defining a positional error of the at least one feature, the method comprising:
directing electromagnetic radiation toward the photomask, the electromagnetic radiation having a wavelength that substantially coincides with a high absorption coefficient of the photomask;
generating a thermal energy increase in the photomask through incidence of the electromagnetic radiation thereon; and
decreasing the positional error as a result of the generating the thermal energy increase in the photomask.
2. The method of claim 1 , further comprising directing the electromagnetic radiation through a material positioned above the photomask.
3. The method of claim 2 , wherein the photomask is at least partially enclosed within a pellicle, and the material is a pellicle film.
4. The method of claim 1 , wherein the laser wavelength is above 8 micrometers.
5. The method of claim 1 , wherein the photomask is a quartz photomask, and the electromagnetic radiation wavelength is about 9 micrometers.
6. The method of claim 1 , wherein a thin film is disposed on the photomask, and the at least one feature is contained in the thin film.
7. The method of claim 6 , wherein the thin film is partially light-absorbing.
8. The method of claim 1 , wherein the decrease in the positional error is a result of at least one of dehydration, oxidation, annealing, and densification.
9. The method of claim 1 , wherein the at least one feature includes a first feature disposed at a first location and a second feature disposed at a second location, the second location being different from the first location, the method further comprising
decreasing a positional error of the first feature by a first amount; and
decreasing a positional error of the second feature by a second amount, the first amount being different from the second amount.
10. The method of claim 1 , wherein the photomask includes a plurality of materials, the electromagnetic radiation is a laser beam, and the laser beam has a wavelength that substantially coincides with a high absorption coefficient of at least two materials of the plurality of materials.
11. A method for improving optical characteristics of a photomask, comprising:
directing electromagnetic radiation toward the photomask, the photomask having a partially-absorbing thin film disposed thereon, the electromagnetic radiation having a wavelength that substantially coincides with a high absorption coefficient of the photomask;
generating a thermal energy increase in the photomask in response to the electromagnetic radiation incident thereon; and
modifying a position of a first feature on the photomask relative to a second feature on the photomask.
12. The method of claim 11 , wherein said modifying includes increasing a distance between the first feature and the second feature.
13. The method of claim 11 , wherein said modifying includes decreasing a distance between the first feature and the second feature.
14. The method of claim 11 , wherein the photomask is at least partially enclosed within a pellicle, the method further comprising directing the electromagnetic radiation through a pellicle film positioned above the photomask.
15. The method of claim 14 , wherein the electromagnetic radiation is further directed toward the thin film, and the electromagnetic radiation has a wavelength that substantially coincides with a high absorption coefficient of the thin film.
16. A method for improving optical characteristics of a photomask, comprising:
directing electromagnetic radiation toward a partially-absorbing thin film disposed on the photomask, the electromagnetic radiation having a wavelength that substantially coincides with a high absorption coefficient of the thin film;
generating a thermal energy increase in the thin film in response to the electromagnetic radiation incident thereon; and
modifying a position of a first feature on the photomask relative to a second feature on the photomask.
17. The method of claim 16 , wherein said modifying includes increasing a distance between the first feature and the second feature.
18. The method of claim 16 , wherein said modifying includes decreasing a distance between the first feature and the second feature.
19. The method of claim 16 , wherein the photomask is at least partially enclosed within a pellicle, the method further comprising directing the electromagnetic radiation through a pellicle film positioned above the photomask.
20. The method of claim 16 , wherein the electromagnetic radiation is further directed toward the photomask, and the electromagnetic radiation has a wavelength that substantially coincides with a high absorption coefficient of the photomask.