Semiconductor device using MEMS technology

• US 20060267109A1
• Filed: 01/30/2006
• Published: 11/30/2006
• Est. Priority Date: 05/30/2005
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Ohguro, Tatsuya
• Granted Patent: US 7,582,940 B2
• Time in Patent Office: Days
• US Class Current: 257/396
• CPC Class Codes: B81C 1/00333 Aspects relating to packaging of MEMS devices, not covered by groups B81C1/00269 - B81C1/00325
• CPC Class Codes: B81C 2203/0136 Growing or depositing of a covering layer
• CPC Class Codes: B81C 2203/0145 Hermetically sealing an opening in the lid

Abstract

A semiconductor device using a MEMS technology according to an example of the present invention comprises a cavity, a lower electrode positioned below the cavity, a moving part positioned in the cavity, an upper electrode coupled with the moving part, a film which covers an upper part of the cavity and has an opening, and a material which closes the opening and seals the cavity.

Claims

1. A semiconductor device using a MEMS technology comprising:

a cavity;

a lower electrode positioned below the cavity;

a moving part positioned in the cavity;

an upper electrode coupled with the moving part;

a first film which covers an upper portion of the cavity and has a first opening; and

a material which closes the first opening and seals the cavity.

2. The semiconductor device according to claim 1, wherein a position of the first opening does not overlap a position of a second opening which allows movement of the moving part as seen from above the cavity.

3. The semiconductor device according to claim 2, wherein the first and second openings are 0.3 μ

m or more away from each other as seen from above the cavity.

4. The semiconductor device according to claim 1, further comprising a second film which covers the first film.

5. The semiconductor device according to claim 1, wherein the material is one selected from a semiconductor including Si or SiGe, an insulator and a conductor.

6. The semiconductor device according to claim 1, wherein a surface of the first film is a curved surface.

7. The semiconductor device according to claim 1, further comprising a column which is positioned inside the cavity and supports the first film.

8. A piezoelectric type variable capacity comprising:

a semiconductor device according to claim 1;

and

a piezoelectric element as an actuator coupled with the moving part.

9. A semiconductor device using a MEMS technology comprising:

a cavity;

a lower electrode which is positioned below the cavity;

a moving part which is positioned in the cavity;

an upper electrode coupled with the moving part; and

a first film which covers an upper portion of the cavity and is formed of a porous material.

10. The semiconductor device according to claim 9, further comprising a second film which covers the first film and has the density higher than that of the first film.

11. The semiconductor device according to claim 9, wherein a surface of the first film is a curved surface.

12. The semiconductor device according to claim 9, further comprising a column which is positioned inside the cavity and supports the first film.

13. A piezoelectric type variable capacity comprising:

a semiconductor device according to claim 9;

and

a piezoelectric element as an actuator coupled with the moving part.

14. A semiconductor device using a MEMS technology comprising:

a cavity;

a lower electrode positioned below the cavity;

a moving part positioned in the cavity;

an upper electrode coupled with the moving part;

a first film which covers an upper portion of the cavity; and

a plurality of columns which are positioned inside the cavity, support the first film and are arranged at a pitch which is not greater than 500 μ

m.

15. The semiconductor device according to claim 14, wherein each of the plurality of columns is a prismatic column or a cylindrical column, and a length of one side of each column or a diameter of the same is not greater than 40 μ

m.

16. The semiconductor device according to claim 14, further comprising a second film which covers the first film.

17. A piezoelectric type variable capacity comprising:

a semiconductor device according to claim 14;

and

a piezoelectric element as an actuator coupled with the moving part.

18. A manufacturing method of the semiconductor device using a MEMS technology comprising:

forming a dummy layer;

forming a film with an opening on the dummy layer;

removing the dummy layer to form a cavity; and

closing the opening to seal the cavity.

19. The manufacturing method according to claim 18, wherein the opening is closed by forming a seed layer around the opening and growing the seed layer by selective growth.

20. A manufacturing method of the semiconductor device using a MEMS technology comprising:

forming a dummy layer;

forming a porous film on the dummy layer;

reacting a reactive gas with the dummy layer and removing the dummy layer to form a cavity; and

forming on the porous film a film having the density higher than that of the porous film.