METHOD OF MANUFACTURING A SEMICONDUCTOR DEVICE
A method of manufacturing a semiconductor device comprises forming a silicon film, converting a surface of the silicon film into a hydrophilic surface, forming an insulating film over the silicon film, and polishing the insulating film formed over the silicon film.
1 . A method of manufacturing a semiconductor device comprising:
forming a silicon film over a semiconductor substrate;
patterning the silicon film;
forming a trench in the semiconductor substrate;
converting at least a surface of the silicon film into a hydrophilic surface;
forming an insulating film over the silicon film and in the trench; and
polishing the insulating film formed over the silicon film.
2 . The method according to claim 1 , wherein the silicon film is a polysilicon film.
3 . The method according to claim 1 , wherein converting the surface into the hydrophilic surface comprises, forming a silicon oxide film at least over the surface of the silicon film by thermally oxidizing the silicon film, or forming a silicon nitride film at least over the surface of the silicon film by having the silicon film reacted with ammonia.
4 . The method according to claim 3 , wherein polishing the insulating film is finished in a state where a surface of the silicon film after polishing shows hydrophilicity.
5 . The method according to claim 2 , wherein surface roughness of the silicon film after polishing is 3 nm or more.
6 . The method according to claim 1 , wherein polishing the insulating film is performed by using abrasive grains having a first mechanical hardness lower than a second mechanical hardness of the surface of the silicon film.
7 . The method according to claim 6 , wherein the abrasive grains are cerium oxide particles.
8 . The method according to claim 1 , wherein converting the surface into the hydrophilic surface is performed after forming the trench and before forming the insulating film.
9 . The method according to claim 1 , wherein converting the surface into the hydrophilic surface is forming a thermal oxide film over the surface of the silicon film in forming the insulating film.
10 . The method according to claim 3 , wherein the silicon oxide film has a thickness of 15 nm or less.
11 . The method according to claim 1 , wherein the silicon film is a film obtained by crystallizing an amorphous silicon layer formed over the semiconductor substrate by subjecting the amorphous silicon layer to heat treatment.
12 . A method of manufacturing a semiconductor device comprising:
forming a polysilicon film over a semiconductor substrate;
patterning the polysilicon film;
forming a trench in the semiconductor substrate;
forming a silicon oxide film over a surface of the polysilicon film by performing heat treatment;
forming an insulating film over the polysilicon film and in the trench; and
polishing the insulating film formed over the polysilicon film using abrasive grains of cerium oxide.
13 . The method according to claim 12 , wherein surface roughness of the polysilicon film after polishing is 3 nm or more.
14 . The method according to claim 12 , wherein forming the silicon oxide film is performed after forming the trench and before forming the insulating film.
15 . The method according to claim 12 , wherein the silicon oxide film has a thickness of 15 nm or less.
16 . The method according to claim 12 , wherein the polysilicon film is a film obtained by crystallizing an amorphous silicon layer formed over the semiconductor substrate by subjecting the amorphous silicon layer to heat treatment.