Gassing-free exposure mask
View Patent ↗The present invention relates to an exposure mask for structuring a photoresist layer on a substrate wafer, in which an inorganic adhesive is used as an adhesive device for connecting a reticle having a lithographic structure, a frame and a pellicle. For chemical reasons, an adhesive of this type has no tendency or a considerably lower tendency to gassing out than an organic adhesive used in conventional exposure masks, so that the risk of particles which are deposited on the lithographic structure and which can cause projection errors during an exposure process is largely ruled out. The invention relates further to a method of producing such an inorganic adhesive and also a method of producing an exposure mask with the aid of such an inorganic adhesive.
1. An exposure mask for structuring a photoresist layer on a substrate wafer, comprising:
a reticle which has a lithographic structure;
a frame; and
a pellicle arranged at a defined distance from the lithographic structure by the frame;
the reticle, the frame and the pellicle each comprising quartz glass and being connected by an adhesive device comprising an inorganic adhesive.
2. The exposure mask as claimed in claim 1 , wherein the inorganic adhesive of the adhesive device is of the waterglass type which includes at least the elements silicon, oxygen and an alkali metal.
3. The exposure mask as claimed in claim 2 , wherein the adhesive device used is a potassium silicate solution.
4. Use of an inorganic adhesive as an adhesive for connecting a reticle, a frame and a pellicle of an exposure mask, wherein the reticle, the frame and the pellicle comprise quartz glass; the reticle having a lithographic structure and the pellicle being arranged at a defined distance from the lithographic structure by the frame.
5. The use of an inorganic adhesive as claimed in claim 4 , wherein the inorganic adhesive is of a waterglass type which includes at least the elements silicon, oxygen and an alkali metal.
6. The use of an inorganic adhesive as claimed in claim 5 , wherein the adhesive is a potassium silicate solution.
7. A method of producing an exposure mask comprising a reticle which has a lithographic structure, a frame and a pellicle, wherein the pellicle is arranged at a defined distance from the lithographic structure by the frame; and wherein the reticle, the frame and the pellicle each comprise quartz glass and are connected by an inorganic adhesive, the method comprising:
a) applying the inorganic adhesive to at least one of a first side of the frame and a side of the pellicle that faces the frame;
b) joining the first side of the frame and the side of the pellicle that faces the frame;
c) applying the inorganic adhesive to at least one of a second side of the frame and a side of the reticle provided with the lithographic structure;
d) joining the first side of the frame and the side of the reticle that faces the frame; and
e) drying the inorganic adhesive.
8. The method as claimed in claim 7 , wherein drying of the inorganic adhesive is carried out between steps b) and c).
9. The method as claimed in claim 7 , wherein the application of the inorganic adhesive is carried out with a roll.
10. The method as claimed in claim 7 , wherein the application of the inorganic adhesive is carried out with a metering cannula.
11. The method as claimed in claim 7 , wherein the inorganic adhesive is of a waterglass type which includes at least elements silicon, oxygen and an alkali metal.
12. The method as claimed in claim 11 , wherein the adhesive used is a potassium silicate solution and the drying of the adhesive is carried out at a temperature of 23° C. and with an atmospheric humidity of 38%.