Semiconductor device and method of manufacturing same
To provide a semiconductor device having improved performance. The semiconductor device has a first insulating film formed on the main surface of a semiconductor substrate and a second insulating film formed on the first insulating film. The semiconductor device further has a first opening portion penetrating through the second insulating film and reaching the first insulating film, a second opening portion penetrating through the first insulating film and reaching the semiconductor substrate, and a trench portion formed in the semiconductor substrate. A first opening width of the first opening portion and a second opening width of the second opening portion are greater than a trench width of the trench portion. The trench portion is closed by a third insulating film while leaving a space in the trench portion.
1. A semiconductor device, comprising:
a semiconductor substrate;
a first insulating film formed over a main surface of the semiconductor substrate and containing silicon and oxygen;
a second insulating film formed over the first insulating film;
a first opening portion penetrating through the second insulating film and reaching the first insulating film;
a second opening portion penetrating through a portion of the first insulating film exposed from the first opening portion and reaching the semiconductor substrate;
a trench portion formed in a portion of the semiconductor substrate exposed from the second opening portion; and
a third insulating film formed in the trench portion, in the second opening portion, and in the first opening portion, wherein
a material of the second insulating film is different from a material of the first insulating film,
a first opening width of the first opening portion and a second opening width of the second opening portion are each greater than a trench width of the trench portion,
the trench portion is closed by the third insulating film while leaving a space in the trench portion, and
the third insulating film covers a portion of the main surface of the semiconductor substrate exposed by the second opening portion.
2. The semiconductor device according to claim 1 , wherein the second opening width of the second opening portion is equal to the first opening width of the first opening portion or greater than the first opening width of the first opening portion.
3. The semiconductor device according to claim 2 , further comprising:
a fourth insulating film formed over the second insulating film and containing silicon and oxygen; and
a third opening portion penetrating through the fourth insulating film and reaching the second insulating film,
wherein the first opening portion penetrates through a portion of the second insulating film exposed from the third opening portion and reaches the first insulating film,
wherein a material of the second insulating film is different from a material of the fourth insulating film,
wherein a third opening width of the third opening portion is equal to the first opening width of the first opening portion or greater than the first opening width of the first opening portion, and wherein the third insulating film lies in the third opening portion.
4. The semiconductor device according to claim 3 ,
wherein the trench portion, the second opening portion, the first opening portion, and the third opening portion are closed by the third insulating film while leaving the space in the trench portion, in the second opening portion, in the first opening portion, and in the third opening portion, and
wherein a height position of an upper end of the space is lower than a height position of an upper surface of the fourth insulating film.
5. The semiconductor device according to claim 1 ,
wherein the trench portion and the second opening portion are closed by the third insulating film while leaving the space in the trench portion and in the second opening portion, and
wherein a height position of an upper end of the space is lower than a height position of a lower surface of the second insulating film.
6. The semiconductor device according to claim 1 , wherein the second insulating film contains silicon and nitrogen.
7. The semiconductor device according to claim 6 , wherein the first insulating film has a silicon oxide film and the second insulating film has a silicon nitride film or a silicon oxynitride film.
8. The semiconductor device according to claim 1 , wherein an etch rate of the second insulating film by a hydrofluoric acid-containing etchant is smaller than an etch rate of the first insulating film by the etchant.
9. The semiconductor device according to claim 3 ,
wherein the first insulating film is formed over the main surface of the semiconductor substrate in a first region of the main surface of the semiconductor substrate, and
wherein the semiconductor device further comprises:
a semiconductor element formed over the main surface of the semiconductor substrate in a second region of the main surface of the semiconductor substrate and including a conductor portion;
a fifth insulating film formed in the same layer as that of the second insulating film so as to cover the semiconductor element in the second region;
a sixth insulating film formed over the fifth insulating film as the same layer as the fourth insulating film and containing silicon and oxygen;
a hole portion penetrating through the sixth insulating film and the fifth insulating film and reaching the conductor portion of the semiconductor element; and
a coupling electrode formed to fill the hole portion and electrically coupled to the conductor portion.
10. A semiconductor device, comprising:
a semiconductor substrate;
a first insulating film formed over a main surface of the semiconductor substrate;
a second insulating film formed over the first insulating film;
a first opening portion penetrating through the second insulating film and reaching the first insulating film;
a second opening portion penetrating through a portion of the first insulating film exposed from the first opening portion and reaching the semiconductor substrate;
a trench portion formed in a portion of the semiconductor substrate exposed from the second opening portion; and
a third insulating film formed in the trench portion, in the second opening portion, and in the first opening portion, wherein
a material of the second insulating film is different from a material of the first insulating film,
a second opening width of the second opening portion is different from a first opening width of the first opening portion, and a smaller one of the first opening width of the first opening portion and the second opening width of the second opening portion is greater than a trench width of the trench portion, and
the trench portion is closed by the third insulating film while leaving a space in the trench portion.
11. The semiconductor device according to claim 10 , further comprising:
a fourth insulating film formed over the second insulating film and containing silicon and oxygen; and
a third opening portion penetrating through the fourth insulating film and reaching the second insulating film, wherein
the first opening portion penetrates through a portion of the second insulating film exposed from the third opening portion and reaches the first insulating film,
the material of the second insulating film is different from a material of the fourth insulating film,
a third opening width of the third opening portion is greater than the smaller one of the first opening width of the first opening portion and the second opening width of the second opening portion, and
the third insulating film lies in the third opening portion.
12. The semiconductor device according to claim 11 , wherein
the trench portion, the second opening portion, the first opening portion, and the third opening portion are closed by the third insulating film while leaving the space in the trench portion, in the second opening portion, in the first opening portion, and in the third opening portion, and
a height position of an upper end of the space is lower than a height position of an upper surface of the fourth insulating film.
13. The semiconductor device according to claim 12 , wherein the first opening width of the first opening portion is less than any of the second opening width of the second opening portion and the third opening width of the third opening portion.
14. A semiconductor device, comprising:
a semiconductor substrate;
a first insulating film formed over a main surface of the semiconductor substrate;
a second insulating film formed over the first insulating film;
a first opening portion penetrating through the second insulating film and reaching the first insulating film;
a second opening portion penetrating through a portion of the first insulating film exposed from the first opening portion and reaching the semiconductor substrate;
a trench portion formed in a portion of the semiconductor substrate exposed from the second opening portion; and
a third insulating film formed in the trench portion, in the second opening portion, and in the first opening portion, wherein
a material of the second insulating film is different from a material of the first insulating film,
a second opening width of the second opening portion is different from a first opening width of the first opening portion, and a smaller one of the first opening width of the first opening portion and the second opening width of the second opening portion is greater than a trench width of the trench portion,
the trench portion is closed by the third insulating film while leaving a space in the trench portion, and
the second opening width of the second opening portion is greater than the first opening width of the first opening portion.
15. The semiconductor device according to claim 10 , wherein
the trench portion and the second opening portion are closed by the third insulating film while leaving the space in the trench portion and in the second opening portion, and
a height position of an upper end of the space is lower than a height position of a lower surface of the second insulating film.
16. The semiconductor device according to claim 10 , wherein the first insulating film contains silicon and oxygen and the second insulating film contains silicon and nitrogen.
17. The semiconductor device according to claim 16 , wherein the first insulating film has a silicon oxide film and the second insulating film has a silicon nitride film or a silicon oxynitride film.