Underlayer composition and method of imaging underlayer
View Patent ↗A method of forming a pattern comprises diffusing an acid, generated by irradiating a portion of a photosensitive layer, into an underlayer comprising an acid sensitive copolymer comprising an acid decomposable group and an attachment group, to form an interpolymer crosslink and/or covalently bonded to the surface of the substrate. Diffusing comprises heating the underlayer and photosensitive layer. The acid sensitive group reacts with the diffused acid to form a polar region at the surface, in the shape of the pattern. The photosensitive layer is removed to forming a self-assembling layer comprising a block copolymer having a block with an affinity for the polar region, and a block having less affinity than the first. The first block forms a domain aligned to the polar region, and the second block forms a domain aligned to the first. Removing either the first or second domain exposes a portion of the underlayer.
1. An underlayer comprising:
an acid sensitive copolymer comprising:
an acid decomposable group;
an attachment group; and
a functional group; and
a photoacid generator,
where the functional group is operative to adjust neutrality of the acid-sensitive copolymer relative to a self-assembling block copolymer that is to be disposed on the underlayer, where the neutrality means that a surface energy of the underlayer is substantially the same as that of at least one block of the block copolymer;
wherein the attachment group is covalently bonded to a hydrophilic surface of a substrate by alkoxide linkages where the attachment group comprises a thiol, a primary or secondary amine substituted, a straight chain or branched C 1-30 alkyl, a C 3-30 cycloalkyl, a C 6-30 aryl, a C 7-30 alkaryl, a C 7-30 aralkyl, a C 1-30 heteroalkyl, a C 3-30 heterocycloalkyl, a C 6-30 heteroaryl, a C 7-30 heteroalkaryl, a C 7-30 heteroaralkyl, or a combination comprising at least one of these groups; and wherein the acid decomposable groups are ester groups, acetal groups, ketal groups, or pyrocarbonate groups.
2. The underlayer of claim 1 , wherein the acid sensitive copolymer has the formula:
wherein R 1 is a C 1-30 acid decomposable group comprising a tertiary alkyl ester group, R 3 is a C 1-30 attachment group comprising a thiol, or primary or secondary amine group, R 5 and R 7 represent the functional group and are independently a C 1-30 aromatic group or ester group, R 2 , R 4 , R 6 , and R 8 are independently H or a C 1-10 organic group, mole fractions w and x are 0.001 to 0.999, mole fractions y and z are 0 to 0.9, and the sum of mole fractions w, x, y, and z is 1.
3. The underlayer of claim 1 , where the acid sensitive copolymer has the structure of formula 1:
wherein R 1 is a C 1-30 acid decomposable group comprising a tertiary alkyl ester group, R 3 is a C 1-30 attachment group, R 5 and R 7 represent the functional group and are independently a C 1-30 aromatic group or an ester group, R 2 , R 4 , R 6 and R 8 are independently H or a C 1-10 organic group, mole fractions w and x are 0.001 to 0.999 and mole fractions y and z are less than 0.9, where the sum of mole fractions w, x, y, and z is 1; or has the structure of formula 2:
wherein R 9 is a C 1-20 acid decomposable group comprising a tertiary alkyl ester group, R 10 is H or a C 1-30 alkyl group, R 2 , R 4 , and R 6 are independently H, methyl, ethyl, or phenyl, mole fraction x is 0.05 to 0.65, mole fraction y is 0.35 to 0.95, and mole fraction z is 0 to 0.9, where the sum of mole fractions x, y, and z is 1; or has the structure of formula (3):
where mole fraction a is 0.05 to 0.65, and mole fraction b is 0.35 to 0.95, and the sum of mole fractions a and b is 1; or has the structure of formula (4):
where mole fraction a is 0.05 to 0.65, mole fraction b is 0.15 to 0.75, and mole fraction c is 0.20 to 0.80, and the sum of mole fractions a, b, and c is 1; or has the structure of formula (5):
where mole fraction a is 0.05 to 0.65, mole fraction b is 0.15 to 0.75, and mole fraction c is 0.20 to 0.80, and the sum of mole fractions a, b, and c is 1; or has the structure of formula (6):
wherein R 11 is a C 1-20 acid decomposable group comprising a tertiary alkyl ester group, R 12 is a C 1-30 hydroxy-containing group, R 13 is H, a C 1-10 alkyl, or C 1-10 alkoxy; R 2 , R 4 , and R 6 are independently H, methyl, ethyl, or phenyl, mole fraction x is 0.05 to 0.65, mole fraction y is 0.35 to 0.95, and mole fraction z is 0 to 0.90, where the sum of mole fractions x, y, and z is 1; or has the structure of formula (7):
where mole fraction a is 0.05 to 0.65, mole fraction b is 0.15 to 0.75, and mole fraction c is 0.2 to 0.8, and the sum of mole fractions a, b, and c is 1; or has the structure of formula (8):
where mole fraction a is 0.05 to 0.65, mole fraction b is 0.15 to 0.75, and mole fraction c is 0.2 to 0.8, and the sum of mole fractions a, b, and c is 1; or has the structure of formula (9):
where mole fraction a is 0.05 to 0.65, mole fraction b is 0.15 to 0.75, mole fraction c is 0.2 to 0.8, mole fraction d is 0.1 to 0.6, and the sum of mole fractions a, b, c, and d is 1.
4. The underlayer of claim 1 , wherein the functional group comprises phenyl, 4-methoxyphenyl, hydroxyphenyl, methyl, ethyl, n-propyl, 2-propyl, n-butyl, 2-butyl, isobutyl, or a combination comprising at least one of the foregoing.
5. The underlayer of claim 1 , wherein the photoacid generator is at least one selected from a sulfonium salt and an iodonium salt.
6. The underlayer of claim 1 , wherein the acid decomposable group is 2-(2-methyl)propyl, 2-(2-methyl)butyl, 1-methylcyclopentyl, 1-ethylcyclopentyl, 1-methylcyclohexyl, 1-ethylcyclohexyl, 2-methyladamantyl, 2-ethyladamantyl, or a combination comprising at least one of the foregoing.