Water mark defect prevention for immersion lithography

A material for use in immersion lithography, comprising:

• a polymer that turns soluble to a base solution in response to reaction with acid;
• a photo-acid generator (PAG) that decomposes to form an acid in response to a radiation energy;
• and
• a quencher capable of neutralizing acid and having a reduced mobility, wherein the quencher includes a structure selected from the group consisting of 1) two ring structures and an alkyl group;
• 2) three ring structures;
• 3) one alkyl group and two ring structures;
• 4) two alkyl groups and a long chain, the long chain having at least two carbon atoms;
• 5) two alkyl groups and a long chain, the long chain having an oxygen atom and at least two carbon atoms;
• 6) one ring structure having an oxygen atom and two long chain structures, each long chain structure having at least two carbon atoms;
• 7) two alkyl groups and one branched structure having two short chains, each short chain having one carbon atom;
• 8) two alkyl groups and one branched structure having two long chains, each long chain having at least two carbon atoms;
• and 9) two alkyl groups and one branched structure having three short chains, each short chain having one carbon atom, and
• wherein the quencher is chemically bonded to the polymer.

A method comprising:

• forming a photo sensitive layer over a wafer, the photo sensitive layer including a quencher chemically bonded to a polymer, wherein the quencher includes a structure selected from the group consisting of 1) two ring structures and an alkyl group;
• 2) three ring structures;
• 3) one alkyl group and two ring structures;
• 4) two alkyl groups and a long chain, the long chain having at least two carbon atoms;
• 5) two alkyl groups and a long chain, the long chain having an oxygen atom and at least two carbon atoms;
• 6) one ring structure having an oxygen atom and two long chain structures, each long chain structure having at least two carbon atoms;
• 7) two alkyl groups and one branched structure having two short chains, each short chain having one carbon atom;
• 8) two alkyl groups and one branched structure having two long chains, each long chain having at least two carbon atoms;
• and 9) two alkyl groups and one branched structure having three short chains, each short chain having one carbon atom;
• immersing the photo sensitive layer in an immersion fluid;
• and
• exposing the photo sensitive layer to a radiation energy.