Underlayer composition and method of manufacturing a semiconductor device

A method of manufacturing a semiconductor device, comprising:

• forming a photoresist underlayer over a semiconductor substrate,
• wherein the photoresist underlayer comprises:
• a polymer;
• a cross linker;
• and
• polycarbonate or polysulfone photocleavable functional groups,
• wherein the photocleavable functional groups are embedded in the cross linker, and
• the cross linker includes
• where C is carbon, n ranges from 1 to 15;
• A and B independently include a hydrogen atom, a hydroxyl group, a halide, an aromatic carbon ring, or a straight or cyclic alkyl, alkoxyl/fluoro, or alkyl/fluoroalkoxyl chain having a carbon number of between 1 and 12, and each carbon C contains A and B;
• a first terminal carbon C at a first end of a carbon C chain includes X and a second terminal carbon C at a second end of the carbon chain includes Y, wherein X and Y independently include an amine group, a thiol group, an isopropyl alcohol group, or an isopropyl amine group, except when n=1 then X and Y are bonded to a same carbon C;
• forming a photoresist layer over the photoresist underlayer;
• selectively exposing the photoresist layer and photoresist underlayer to actinic radiation;
• decreasing a glass transition temperature (Tg), decreasing a density, or increasing a porosity of a portion of the photoresist underlayer selectively exposed to the actinic radiation by photocleaving the polycarbonate or polysulfone photocleavable functional group;
• and
• developing the selectively exposed photoresist layer to form a patterned photoresist layer.

A method of manufacturing a semiconductor device, comprising:

• forming a first layer over a semiconductor substrate,
• wherein the first layer comprises:
• a cross linker;
• a main polymer;
• and
• a polycarbonate or polysulfone photocleavable functional group embedded in the cross linker,
• wherein the cross linker includes
• where C is carbon, n ranges from 1 to 15;
• A and B independently include a hydrogen atom, a hydroxyl group, a halide, an aromatic carbon ring, or a straight or cyclic alkyl, alkoxyl/fluoro, or alkyl/fluoroalkoxyl chain having a carbon number of between 1 and 12, and each carbon C contains A and B;
• a first terminal carbon C at a first end of a carbon C chain includes X and a second terminal carbon C at a second end of the carbon chain includes Y, wherein X and Y independently include an amine group, a thiol group, an isopropyl alcohol group, or an isopropyl amine group, except when n=1 then X and Y are bonded to a same carbon C, and
• the first layer has a first glass transition temperature, first density, and first porosity;
• forming a resist layer over the first layer;
• decreasing the first glass transition temperature to a second glass transition temperature, decreasing the first density to a second density, or increasing the first porosity of a first portion of the first layer to a second porosity by photocleaving the polycarbonate or polysulfone photocleavable functional group;
• and
• removing a first portion of the resist layer,
• wherein a remaining second portion of the resist layer after the removing the first portion of the resist layer overlies the first portion of the first layer having the second glass transition temperature, second density, or second porosity.