Pellicle for protection of photolithographic mask

A frame-supported pellicle for dust-proofing of a photolithographic mask which comprises:

• (a) a frame member;
• (b) a transparent film of a polymeric material flatly supported by the frame member by adhesive bonding;
• and
• (c) a layer of a sticky adhesive on one of the surfaces of the transparent film of a polymeric material, the sticky adhesive being an organopolysiloxone composition comprising:
• (A) 100 parts by weight of an organopolysiloxane resin consisting of monofunctional siloxane units expressed by the unit formula (CH.sub.3).sub.3 SiO.sub.0.5 and tetravalent siloxane units expressed by the unit formula SiO.sub.2 in a molar ratio in the range from 1:0.4 to 1:1.5;
• and
• (B) from 20 to 50 parts by weight of a diorganopolysiloxane represented by the general formula
• R.sup.1 --SiMe.sub.2 --O--(--SiMe.sub.2 --O--).sub.x --(--SiMeR.sup.2 --O--).sub.y --SiMe.sub.2 --R.sup.1,
• in which Me is a methyl group, R.sup.1 is a hydroxy group, methyl group or vinyl group, R.sup.2 is a methyl group or vinyl group, x is a positive integer and y is 0 or a positive integer with the proviso that x+y is in the range from 100 to 10,000;
• or a partial or complete condensation product thereof.