Naphthalene derivative, resist bottom layer material, resist bottom layer forming method, and patterning process

A resist bottom layer material comprising a naphthalene derivative having the general formula (1):

• wherein cyclic structures Ar1 and Ar2 denote a benzene or naphthalene ring, X is a single bond or C1-C20 alkylene, m is 0 or 1, and n is such a natural number as to provide a molecular weight of up to 100,000, or
• a naphthalene derivative comprising a partial structure having the general formula (2):
• wherein cyclic structures Ar1 and Ar2 denote a benzene or naphthalene ring, X is a single bond or C1-C20 alkylene, m is 0 or 1, Y is a single bond or C1-C20 alkylene, p and q each are 0 or a natural number, with the proviso that p and q are not equal to 0 at the same time, and n′ is such a natural number as to provide a molecular weight of up to 200,000, or
• a polymer comprising the naphthalene derivative.

A method for forming a resist bottom layer which is included in a multilayer resist film of at least three layers used in the lithography, comprising the steps of:

• coating a resist bottom layer material onto a substrate, and
• heat treating the coating of resist bottom layer material at a temperature of more than 150° C. to 600° C. for 10 to 600 seconds for curing,
• wherein the resist bottom layer material comprises a naphthalene derivative having the general formula (1):
• wherein cyclic structures Ar1 and Ar2 denote a benzene or naphthalene ring, X is a single bond or C1-C20 alkylene, m is 0 or 1, and n is such a natural number as to provide a molecular weight of up to 100,000, or
• a naphthalene derivative comprising a partial structure having the general formula (2):
• wherein cyclic structures Ar1 and Ar2 denote a benzene or naphthalene ring, X is a single bond or C1-C20 alkylene, m is 0 or 1, Y is a single bond or C1-C20 alkylene, p and q each are 0 or a natural number, with the proviso that p and q are not equal to 0 at the same time, and n′ is such a natural number as to provide a molecular weight of up to 200,000, or
• a polymer comprising one or both of the naphthalene derivatives.