Silicon-containing resist underlayer film-forming composition and patterning process

A silicon-containing resist underlayer film-forming composition containing at least a solvent having a boiling point of 180° C. or higher and any one of a condensation product and a hydrolysis condensation product or both of a mixture comprising:

• one or more kinds of a compound (A) selected from the group consisting of an organic boron compound shown by the following general formula (1) and a condensation product thereof and
• one or more kinds of a silicon compound (B) shown by the following general formula (2),
• R1m0B(OH)m1(OR)(3-m0-m1) (1)
• wherein
• R represents an organic group having 1 to 6 carbon atoms and optionally forming a cyclic organic group by bonding of two ORs;
• R1 represents an organic group selected from the group consisting of a methyl group, an ethyl group, a propyl group, a n-butyl group, a tert-butyl group, a cyclohexyl group, a phenyl group, and those groups shown below:
• where (B) represents a bonded site to B in the general formula (1), and optionally forming a cyclic organic group by bonding of two R1s;
• and
• m0 represents 1 or 2, m1 represents 0, 1, or 2, and 1≦m0+m1≦3,
• R10m10R11m11R12m12Si(OR13)(4-m10-m11-m12) (2)
• wherein
• R13 represents an organic group having 1 to 6 carbon atoms;
• each of R10, R11, and R12 represents a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms;
• and
• m10, m11, and m12 represent 0 or 1, and 0≦m10+m11+m12≦3.