Resist underlayer film forming composition containing silicon having ester group

A resist underlayer film forming composition for lithography, comprising:

• as a silane, a hydrolyzable silane, a hydrolysis product thereof, or a hydrolysis-condensation product thereof, wherein
• the hydrolyzable silane includes a hydrolyzable silane of Formula (1) or a hydrolyzable silane containing a combination of a hydrolyzable silane of Formula (1) with a hydrolyzable silane of Formula (2), and
• a content of the hydrolyzable silane of Formula (1) or the hydrolyzable silane containing a combination of a hydrolyzable silane of Formula (1) with a hydrolyzable silane of Formula (2) in all silanes is less than 50% by mole,
• R1aR2bSi(R3)4−(a+b) Formula (1)
• [in Formula (1), R1 is a monovalent organic group containing a group of Formula (1-1), Formula (1-2), Formula (1-3), Formula (1-4), or Formula (1-5):
• (in Formula (1-1), Formula (1-2), Formula (1-3), Formula (1-4), and Formula (1-5), each of T1, T4, and T7 is an alkylene group, a cyclic alkylene group, an alkenylene group, an arylene group, a sulfur atom, an oxygen atom, an oxycarbonyl group, an amido group, a secondary amino group, or a combination of these groups and atoms;
• T2 is an alkyl group;
• each of T3 and T5 is an aliphatic ring or an aromatic ring;
• each of T6 and T8 is a lactone ring;
• and n is an integer of 1 or 2) and is bonded to a silicon atom through a Si—C bond;
• R2 is an alkyl group, an aryl group, a halogenated alkyl group, a halogenated aryl group, an alkenyl group, or an organic group having an epoxy group, an acryloyl group, a methacryloyl group, a mercapto group, an amino group, or a cyano group, and is bonded to a silicon atom through a Si—C bond;
• R3 is an alkoxy group, an acyloxy group, or a halogen group;
• and a is an integer of 1, b is an integer of 0 or 1, and a+b is an integer of 1 or 2],
• R4a1R5b1Si(R6)4−(a1+b1) Formula (2)
• [in Formula (2), R4 is a monovalent organic group containing a group of Formula (2-1), Formula (2-2), or Formula (2-3):
• and is bonded to a silicon atom through a Si—C bond;
• R5 is an alkyl group, an aryl group, a halogenated alkyl group, a halogenated aryl group, an alkenyl group, or an organic group having an epoxy group, an acryloyl group, a methacryloyl group, a mercapto group, an amino group, or a cyano group, and is bonded to a silicon atom through a Si—C bond;
• R6 is an alkoxy group, an acyloxy group, or a halogen group;
• and a1 is an integer of 1, b1 is an integer of 0 or 1, and a1+b1 is an integer of 1 or 2].