Method to reduce line edge roughness for EUV photoresist pattern

A molecular layer deposition method comprising:

• flowing a first precursor over an EUV photoresist comprising a patterned surface having surface irregularities, the first precursor having a general formula R1—(X)n
• wherein R1 comprises one or more of an alkyl group, an alkenyl group, an aryl group, an aromatic group, and a cycloalkyl group, Xn comprises one or more of a hydroxide group, an aldehyde group, a ketone group, an acid group, an amino group, an isocyanate group, a thiocyanate group, and an acyl chloride group, and n is an integer in a range of from 1 to 6,
• wherein the first precursor reacts with a reactive group on the patterned surface to form a first portion of a carbon-containing film;
• removing a first precursor effluent comprising the first precursor from the EUV photoresist;
• flowing a second precursor over the EUV photoresist, the second precursor having a general formula R2—(Y)n
• wherein R2 comprises one or more of an alkyl group, an alkenyl group, an aryl group, an aromatic group, and a cycloalkyl group, Yn comprises one or more of a hydroxide group, an aldehyde group, a ketone group, an acid group, an amino group, an isocyanate group, a thiocyanate group, and an acyl chloride group, and n is an integer in a range of from 1 to 6,
• wherein the second precursor reacts with the first portion to form a conformal carbon-containing film having substantially no surface irregularities
• wherein the carbon-containing film reduces line edge roughness (LER) and reduces line width roughness (LWR) of the EUV photoresist;
• removing a second precursor effluent comprising the second precursor from the EUV photoresist;
• and
• etching the EUV photoresist to remove a portion of the carbon-containing film from a top surface of the patterned surface.

A method of reducing line edge roughness (LER) of an EUV photoresist, the method comprising molecular layer deposition of a carbon-containing film on a patterned surface of the EUV photoresist, wherein the molecular layer deposition comprises:

• flowing a first precursor over the EUV photoresist comprising the patterned surface having surface irregularities to form a first portion of the carbon-containing film on the patterned surface, the first precursor having a general formula R1—(X)n
• wherein R1 comprises one or more of an alkyl group, an alkenyl group, an aryl group, an aromatic group, and a cycloalkyl group, Xn comprises one or more of a hydroxide group, an aldehyde group, a ketone group, an acid group, an amino group, an isocyanate group, a thiocyanate group, and an acyl chloride group, and n is an integer in a range of from 1 to 6;
• removing a first precursor effluent comprising the first precursor from the EUV photoresist;
• flowing a second precursor over the EUV photoresist, the second precursor having a general formula R2—(Y)n
• wherein R2 comprises one or more of an alkyl group, an alkenyl group, an aryl group, an aromatic group, and a cycloalkyl group, Yn comprises one or more of a hydroxide group, an aldehyde group, a ketone group, an acid group, an amino group, an isocyanate group, a thiocyanate group, and an acyl chloride group, and n is an integer in a range of from 1 to 6;
• wherein the second precursor reacts with the first precursor to form the carbon-containing film conformally on the patterned surface and to substantially remove the surface irregularities;
• and
• removing a second precursor effluent comprising the second precursor from the EUV photoresist,
• wherein the carbon-containing film is formed on a sidewall of the EUV photoresist and reduces line edge roughness (LER) and line width roughness (LWR) of the EUV photoresist.