Method of manufacturing semiconductor device
View Patent ↗A method of manufacturing a semiconductor device including a buried insulating film formed in a bottom part of a trench and a buried-type gate electrode formed in the trench, the method including selectively forming an insulating film in the bottom part of the trench, forming a resist having an opening in a part that corresponds to a region where a device isolation insulating film is formed on a surface of a semiconductor substrate after forming the insulating film, and oxidizing the surface of the semiconductor substrate in the opening to form the device isolation insulating film.
1. A method of manufacturing a semiconductor device including a buried insulating film formed in a bottom part of a trench and a buried-type gate electrode formed in the trench, the method comprising:
selectively forming an insulating film in the bottom part of the trench such that a side wall of the trench is not covered by the insulating film;
forming a mask having an opening in a part that corresponds to a region where a device isolation insulating film is formed on a surface of a semiconductor substrate after forming the insulating film, the mask including an oxide film and a nitride film; and
oxidizing the surface of the semiconductor substrate in the opening to form the device isolation insulating film,
wherein the step of oxidizing the surface of the semiconductor substrate in the opening to form the device isolation insulating film is performed after the step of selectively forming the insulating film in the bottom part of the trench.
2. The method of manufacturing the semiconductor device according to claim 1 , further comprising:
forming a gate oxide film having a film thickness smaller than that of the buried insulating film over the side wall of the trench after forming the device isolation insulating film; and
burying a gate electrode material in the trench after forming the gate oxide film.
3. The method of manufacturing the semiconductor device according to claim 1 , further comprising:
forming a first diffusion region that functions as a body region of a transistor in a region that is adjacent to the trench; and
forming a second diffusion region that functions as a source region of the transistor in a region that is adjacent to the trench in the upper layer of the first diffusion region.
4. The method of manufacturing the semiconductor device according to claim 1 , wherein the device isolation insulating film is formed along with an outer periphery of an active region that functions as a transistor in the semiconductor substrate.
5. The method of manufacturing the semiconductor device according to claim 1 , wherein a transistor formed in the semiconductor device is a vertical field effect transistor having a gate electrode formed in the trench, a source region in a front surface side of the semiconductor substrate, and a drain region in a rear surface side of the semiconductor substrate.
6. A method of manufacturing a semiconductor device including a buried insulating film formed in a bottom part of a trench and a buried-type gate electrode formed in the trench, the method comprising:
selectively forming an insulating film in the bottom part of the trench such that a side wall is not covered by the insulating film;
forming an oxide film after the selectively forming an insulating film;
forming a nitride film after the forming a oxide film;
forming an opening in the nitride film and the oxide film in a part that corresponds to a region where a device isolation insulating film is formed on a surface of a semiconductor substrate; and
oxidizing the surface of the semiconductor substrate in the opening to form the device isolation insulating film,
wherein the step of oxidizing the surface of the semiconductor substrate in the opening to form the device isolation insulating film is performed after the step of selectively forming the insulating film.
7. The method of manufacturing the semiconductor device according to claim 6 , further comprising:
forming a gate oxide film having a film thickness smaller than that of the buried insulating film over the side wall of the trench after forming the device isolation insulating film; and
burying a gate electrode material in the trench after forming the gate oxide film.
8. The method of manufacturing the semiconductor device according to claim 6 , further comprising:
forming a first diffusion region that functions as a body region of a transistor in a region that is adjacent to the trench; and
forming a second diffusion region that functions as a source region of the transistor in a region that is adjacent to the trench in the upper layer of the first diffusion region.
9. The method of manufacturing the semiconductor device according to claim 6 , wherein the device isolation insulating film is formed along with an outer periphery of an active region that functions as a transistor in the semiconductor substrate.
10. The method of manufacturing the semiconductor device according to claim 6 , wherein a transistor formed in the semiconductor device is a vertical field effect transistor having a gate electrode formed in the trench, a source region in a front surface side of the semiconductor substrate, and a drain region in a rear surface side of the semiconductor substrate.