Composition for forming resist underlying film

A resist underlayer film-forming composition comprising a hydrolysis condensate of a hydrolyzable silane mixture containing an alkyltrialkoxysilane and at least two hydrolyzable silanes, comprising a first and a second hydrolyzable silane, of the following Formula (1):

• R1aR2bSi(R3)4-(a+b) (1)
• wherein in both the first and the second hydrolysable silane:
• R2 is a group bonded to the silicon atom, and is each independently a substitutable alkyl group, a substitutable halogenated alkyl group, a substitutable alkoxyalkyl group, or an organic group containing an epoxy group, an acryloyl group, a methacryloyl group, a mercapto group, an amino group, an amide group, an alkoxy group, a sulfonyl group, or a cyano group, or any combination of these;
• R3 is a group or atom bonded to the silicon atom, and is each independently an alkoxy group, an aralkyloxy group, an acyloxy group, or a halogen atom;
• a is 1;
• b is an integer of 0 to 2;
• and
• 4−(a+b) is an integer of 1 to 3,
• wherein in the first hydrolyzable silane, R1 is a group bonded to the silicon atom, and is an organic group containing a succinic anhydride skeleton, and
• wherein in the second hydrolyzable silane, R1 is a group bonded to the silicon atom, and is a group of the following Formula (1-2):
• wherein X101 is any of groups of the following Formula (1-3) to (1-5), and the carbon atom of the ketone group in each of the following Formula (1-4) and (1-5) is bonded to the nitrogen atom bonded to R102 in Formula (1-2):
• wherein R103 to R107 are each independently a hydrogen atom, a substitutable alkyl group, a substitutable alkenyl group, or an organic group containing an epoxy group or a sulfonyl group;
• R101 is each independently a hydrogen atom, a substitutable alkyl group, a substitutable alkenyl group, or an organic group containing an epoxy group or a sulfonyl group;
• R102 is each independently an alkylene group, a hydroxyalkylene group, a sulfide bond (—S—), an ether bond (—O—), or an ester bond (—C(═O)—O— or —O—C(═O)—);
• and
• wherein the amount of the alkyltrialkoxysilane contained in the hydrolyzable silane mixture is 0% by mole or more and less than 40% by mole relative to the total amount by mole of all hydrolyzable silanes contained in the hydrolyzable silane mixture.