A patterning process for forming a negative pattern by lithography, comprising at least the steps of: using a composition for forming silicon-containing film, containing a silicon-containing compound and an organic solvent, to form a silicon-containing film; wherein the silicon-containing compound is obtained by hydrolytically condensing a mixture comprising: one or more kinds selected from a hydrolyzable silicon compound represented by the following general formula (A-1), a hydrolyzate of the compound, a condensate of the compound, and a hydrolysis condensate of the compound; and one or more kinds selected from a reactive compound represented by the following general formula (A-2-2), a hydrolyzate of the compound, a condensate of the compound, and a hydrolysis condensate of the compound, (R 2) m2 (OR 3) (3-m2) Si-R 1 -Si(R 4) m4 (OR 5) (3-m4) (A-1) U(OR 21) m21 (OR 22) m22 m23/2 (A-2-2),wherein R 1 represents a single bond, or a divalent organic group having 1 to 20 carbon atoms, each R 2 and R 4 independently represent a hydrogen atom, or a monovalent organic group having 1 to 20 carbon atoms, each R 3 and R 5 independently represent a hydrogen atom, or an alkyl group having 1 to 6 carbon atoms, and m2 and m4 represent integers satisfying that 0≤m2+m4≤2; each R 21 and R 22 independently represent a hydrogen atom, or an organic group having 1 to 30 carbon atoms, m21+m22+m23/2 represents a valence to be determined by a kind of U, each m21, m22, and m23 independently represent an integer of 0 or more, and U represents one of elements belonging to the III group, IV group, and V group in the periodic table, except for carbon and silicon; using a silicon-free resist composition to form a photoresist film on the silicon-containing film; heat-treating the photoresist film, and subsequently exposing the photoresist film to a high energy beam; and using a developer comprising an organic solvent to dissolve an unexposed area of the photoresist film, thereby obtaining a negative pattern. using a composition for forming silicon-containing film, containing a silicon-containing compound and an organic solvent, to form a silicon-containing film; wherein the silicon-containing compound is obtained by hydrolytically condensing a mixture comprising: one or more kinds selected from a hydrolyzable silicon compound represented by the following general formula (A-1), a hydrolyzate of the compound, a condensate of the compound, and a hydrolysis condensate of the compound; and one or more kinds selected from a reactive compound represented by the following general formula (A-2-2), a hydrolyzate of the compound, a condensate of the compound, and a hydrolysis condensate of the compound, (R 2) m2 (OR 3) (3-m2) Si-R 1 -Si(R 4) m4 (OR 5) (3-m4) (A-1) U(OR 21) m21 (OR 22) m22 m23/2 (A-2-2),wherein R 1 represents a single bond, or a divalent organic group having 1 to 20 carbon atoms, each R 2 and R 4 independently represent a hydrogen atom, or a monovalent organic group having 1 to 20 carbon atoms, each R 3 and R 5 independently represent a hydrogen atom, or an alkyl group having 1 to 6 carbon atoms, and m2 and m4 represent integers satisfying that 0≤m2+m4≤2; each R 21 and R 22 independently represent a hydrogen atom, or an organic group having 1 to 30 carbon atoms, m21+m22+m23/2 represents a valence to be determined by a kind of U, each m21, m22, and m23 independently represent an integer of 0 or more, and U represents one of elements belonging to the III group, IV group, and V group in the periodic table, except for carbon and silicon; using a silicon-free resist composition to form a photoresist film on the silicon-containing film; heat-treating the photoresist film, and subsequently exposing the photoresist film to a high energy beam; and using a developer comprising an organic solvent to dissolve an unexposed area of the photoresist film, thereby obtaining a negative pattern. R 1 represents a single bond, or a divalent organic group having 1 to 20 carbon atoms, each R 2 and R 4 independently represent a hydrogen atom, or a monovalent organic group having 1 to 20 carbon atoms, each R 3 and R 5 independently represent a hydrogen atom, or an alkyl group having 1 to 6 carbon atoms, and m2 and m4 represent integers satisfying that 0≤m2+m4≤2; each R 21 and R 22 independently represent a hydrogen atom, or an organic group having 1 to 30 carbon atoms, m21+m22+m23/2 represents a valence to be determined by a kind of U, each m21, m22, and m23 independently represent an integer of 0 or more, and U represents one of elements belonging to the III group, IV group, and V group in the periodic table, except for carbon and silicon; using a silicon-free resist composition to form a photoresist film on the silicon-containing film; heat-treating the photoresist film, and subsequently exposing the photoresist film to a high energy beam; and using a developer comprising an organic solvent to dissolve an unexposed area of the photoresist film, thereby obtaining a negative pattern.