Superfine pattern mask, method for production thereof, and method employing the same for forming superfine pattern

A composition for forming a superfine pattern, comprising perhydropolysilazane (I), silicon-containing polymer (II) having a hydrocarbon group, and a solvent which dissolves said perhydropolysilazane (I) and said silicon-containing polymer (II) but which does not dissolve a resist pattern;

• wherein the mixture of said perhydropolysilazane (I) and said silicon-containing polymer (II) contains silicon-hydrogen bonds and silicon-hydrocarbon group bonds in such amounts that the number of the silicon-hydrocarbon group bonds is in a ratio of 1 to 44% based on the total number of the silicon-hydrogen bonds and the silicon-hydrocarbon group bonds and further wherein said silicon-containing polymer (II) is chosen from the group consisting of
• a) a silicon-containing polymer (II) comprising a repeating unit represented by the following formula (IIa):
• in which each Ra may be the same or different from each other and is selected from the group consisting of hydrogen, an alkyl group having 1 to 6 carbon atoms, a fully or partly fluorinated alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkylamino group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms, provided that all the Ras contained in said silicon-containing polymer (II) are not hydrogen atoms at the same time and that the weight average molecular weight is in the range of 500 to 6000;
• b) a silicon-containing polymer (II) comprising a repeating unit represented by the following formula (IIc):
• [RcSiO1.5] (IIc)
• in which Rc is selected from the group consisting of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkylamino group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms, provided that all the Rcs contained in said repeating unit (IIc) are not hydrogen atoms at the same time and that the weight average molecular weight is in the range of 1000 to 8000 and
• c) a silicon-containing polymer (II) comprising a repeating unit represented by the following formula (IIb):
• in which each Rb may be the same or different from each other and is selected from the group consisting of hydrogen and an alkyl group having 1 to 6 carbon atoms, provided that all the Rbs contained in said repeating unit (IIb) are not hydrogen atoms at the same time and that the weight average molecular weight is in the range of 650 to 6000 wherein said silicon-containing polymer-comprising a repeating unit represented by the formula (IIb) is methylhydropolysilazane.