Method for manufacturing semiconductor device, and polishing apparatus
View Patent ↗An interlayer insulating film is formed on a semiconductor substrate having a semiconductor element formed thereon. At this time, there are protrusions higher than surroundings thereof and non-protruding portions lower than the protrusions on the surface of the interlayer insulating film. First, a first polishing process is carried out on the surface of the interlayer insulating film with use of a first abrasive having non-Prestonian properties produced by mixing abrasive materials including abrasive grains, a polymer additive and water at a predetermined first mixture ratio. Then, after the first abrasive process shifts to an automatically stopping state, a second polishing process is carried out on the surface of the interlayer insulating film with use of a second abrasive having the concentration of polymer additive lower than that of the first abrasive and produced by mixing the abrasive materials at a second mixture ratio different from the first mixture ratio.
1. A method for manufacturing a semiconductor device comprising:
forming a film to be polished made of an insulating film or a conductive film on a semiconductor substrate; and
flattening a surface of the film after the forming step, wherein the flattening step comprises a first polishing process carried out on the surface of the film using a first abrasive with non-Prestonian properties produced by mixing abrasive materials, including abrasive grains, a polymer additive and water, at a predetermined first mixture ratio, and
a second polishing process carried out on the surface of the film using a second abrasive produced by mixing the abrasive materials at a predetermined second mixture ratio different from the first mixture ratio to make a concentration of the polymer additive lower than that of the first abrasive, wherein the second abrasive is produced so as to have the concentration of the polymer additive equal to or lower than ¼ of that of the first abrasive;
wherein the second polishing process is carried out after the first polishing process shifts to an automatically stopping state in which polishing hardly progresses;
wherein the first polishing process is carried out under a predetermined first polishing pressure and the second polishing process is carried out under a second polishing pressure higher than the first polishing pressure; and
wherein the second polishing process is carried out on the surface of the film in a surface state which causes the first polishing process to shift to the automatically stopping state at a polishing rate equal to or more than 200 nm per minute.
2. The method for manufacturing a semiconductor device according to claim 1 , wherein
the second polishing process comprises removing a surface of the film by thickness of a region including at least part of defects generated in the film in the first polishing process.
3. The method for manufacturing a semiconductor device according to claim 1 , wherein
the second abrasive is produced so as to have the concentration of the polymer additive equal to ¼ of that of the first abrasive.
4. The method for manufacturing a semiconductor device according to claim 1 wherein the first polishing process is carried out using the first abrasive obtained by mixing the supplied abrasive materials at the first mixture ratio controlled by a polishing apparatus, and the second polishing process is carried out using the second abrasive obtained by mixing the supplied abrasive materials at the second mixture ratio controlled by the polishing apparatus.
5. The method for manufacturing a semiconductor device according to claim 1 , wherein
the second polishing process is completed when the film is polished by a thickness equal to or more than 30 nm.
6. The method for manufacturing a semiconductor device according to claim 1 , wherein
the film is a silicon oxide film formed in accordance with an HDP method.
7. The method for manufacturing a semiconductor device according to claim 1 , wherein
the second abrasive is produced so as to have the concentration of the polymer additive lower than ¼ of that of the first abrasive.