Pellicle for photomask and method of fabricating the same
A pellicle for a photomask comprises a pellicle membrane. The pellicle membrane incudes a base layer having a first surface and a second surface facing the first surface, and a first recovery layer covering the first surface of the base layer. A content of SP2 covalent bonds between carbon atoms contained in the first recovery layer is less than or equal to a content of SP2 covalent bonds between carbon atoms contained in the base layer.
1. A method of fabricating a pellicle for a photomask, the method comprising:
providing a pellicle membrane; and
transcribing the pellicle membrane onto a frame,
wherein providing the pellicle membrane includes,
forming a base layer having a first surface and a second surface facing the first surface,
coating a first carbon-containing material on the first surface of the base layer, and
performing a first heat treatment process at a first process temperature to form a first recovery layer that is bonded to the base layer,
wherein the first carbon-containing material includes a catecholamine.
2. The method of claim 1 , wherein providing the pellicle membrane further includes:
forming a support layer;
providing the support layer on the second surface of the base layer; and
performing a second heat treatment process at a second process temperature to bond the support layer to the base layer.
3. The method of claim 2 , wherein
the first process temperature is between 900 and 2,000° C., and
the second process temperature is between 100 and 300° C.
4. The method of claim 1 , wherein
the base layer includes one of graphene, graphite, or both graphene and graphite, and
a content of SP3 covalent bonds between carbon atoms contained in the first recovery layer greater than a content of SP3 covalent bonds between carbon atoms contained in the base layer.
5. The method of claim 1 , wherein forming the base layer includes providing vapor of a second carbon-containing material to deposit carbon atoms on a catalytic metal substrate.
6. The method of claim 1 , wherein the base layer includes a first pinhole on the first surface,
wherein coating the first carbon-containing material includes filling the first pinhole with the first carbon-containing material.
7. The method of claim 6 , wherein the base layer further includes a second pinhole on the second surface,
wherein providing the pellicle membrane further includes,
coating a third carbon-containing material on the second surface of the base layer to fill the second pinhole with the third carbon-containing material, and
performing a heat treatment process to form a second recovery layer bonded to the base layer,
wherein the third carbon-containing material includes a catecholamine.