Micro-electro-mechanical device and method of manufacturing the same

• US 8,168,461 B2
• Filed: 12/08/2010
• Issued: 05/01/2012
• Est. Priority Date: 11/07/2007
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Tsuchiya, Kaoru, Mizoguchi, Takafumi
• Primary Examiner(s): Smith, Zandra
• Assistant Examiner(s): Duong, Khanh
• Application Number:
  US12/963,483
• Publication Number:
  US 20110159626A1
• Time in Patent Office: 510 Days
• Field of Search: None
• US Class Current: 438/50
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2203/0315 Cavities
• CPC Class Codes: B81B 3/007 For controlling stiffness, e.g. ribs
• CPC Class Codes: Y10S 977/724 Devices having flexible or movable element
• CPC Class Codes: Y10S 977/732 Nanocantilever
• CPC Class Codes: Y10S 977/733 Nanodiaphragm
• CPC Class Codes: Y10T 428/249953 Composite having voids in a component [e.g., porous, cellular, etc.]

Abstract

The present invention improves mechanical strength of a micro-electro-mechanical device (MEMS) having a movable portion to improve reliability. In a micro-electro-mechanical device (MEMS) having a movable portion, a portion which has been a hollow portion in the case of a conventional structure is filled with a filler material. As the filler material, a block copolymer that is highly flexible is used, for example. By filling the hollow portion, mechanical strength improves. Besides, warpage of an upper portion of a structure body in the manufacture process is prevented, whereby yield improves. A micro-electro-mechanical device thus manufactured is highly reliable.

Claims

1. A method of manufacturing a micro-electro-mechanical device, comprising:

forming a lower electrode layer on an insulating surface;

forming a first filler material layer including plural kinds of materials over the lower electrode layer;

inducing phase separation in the first filler material layer;

forming an upper electrode layer over the first filler material layer;

forming a structure layer over the upper electrode layer; and

forming a porous second filler material layer by removing any of the materials included in the first filler material layer.

2. The method according to claim 1, wherein any of the materials included in the first filler material layer is removed by etching.

3. The method according to claim 1, wherein a porosity of the second filler material layer is greater than or equal to 20% and less than or equal to 80%.

4. The method according to claim 1, wherein the structure layer includes a portion capable of moving in a direction toward the lower electrode layer or in a direction opposite to the direction toward the lower electrode layer.

5. The method according to claim 1, wherein the porous second filler material layer has a cylinder structure, a gyroid structure, or a lamellar structure.

6. The method according to claim 1, wherein the first filler material layer is formed so as to cover the lower electrode layer.

7. A method of manufacturing a micro-electro-mechanical device, comprising:

forming a lower electrode layer on an insulating surface;

covering an entire surface of the lower electrode layer with a film including block copolymer, the block copolymer including plural kinds of materials;

selectively forming a mask over the film including block copolymer;

forming a first filler material layer by etching the film including block copolymer using the mask;

forming an upper electrode layer over the first filler material layer;

forming a structure layer over the upper electrode layer, and

forming a porous second filler material layer by removing any of the plural kinds of materials included in the block copolymer.

8. The method according to claim 7, wherein the mask is a metal mask.

9. The method according to claim 7, wherein any of the materials included in the first filler material layer is removed by etching.

10. The method according to claim 7, wherein a porosity of the second filler material layer is greater than or equal to 20% and less than or equal to 80%.

11. The method according to claim 7, wherein the structure layer includes a portion capable of moving in a direction toward the lower electrode layer or in a direction opposite to the direction toward the lower electrode layer.

12. The method according to claim 7, wherein the block copolymer includes at least one material selected from a group consisting of hydrophobic aromatic hydrocarbon, hydrophobic aliphatic unsaturation hydrocarbon, hydrophilic aliphatic hydrocarbon, hydrophilic aromatic hydrocarbon, hydrophobic siloxane, and metal complex.

13. The method according to claim 7, wherein the block copolymer includes at least one material selected from a group consisting of polymethylmethacrylate, polystyrene, polyfluorene, polybutadiene, polyisoprene, polyvinyl alcohol, polyethylene glycol, polyvinyl pyridine, polystyrene sulfonic acid, poly dimethylsiloxane, and poly ferrocene.

14. The method according to claim 7, wherein the porous second filler material layer has a cylinder structure, a gyroid structure, or a lamellar structure.

15. A method of manufacturing a micro-electro-mechanical device, comprising:

forming a lower electrode layer on an insulating surface;

forming a first filler material layer including plural kinds of materials covering and in direct contact with the lower electrode layer;

forming an upper electrode layer over the first filler material layer;

forming a structure layer over the upper electrode layer; and

forming a porous second filler material layer by removing any of the materials included in the first filler material layer.

16. The method according to claim 15, further comprising:

inducing phase separation in the first filler material layer.

17. The method according to claim 15, wherein the structure layer includes a portion capable of moving in a direction toward the lower electrode layer or in a direction opposite to the direction toward the lower electrode layer.

18. The method according to claim 15, wherein the porous second filler material layer has a cylinder structure, a gyroid structure, or a lamellar structure.

19. The method according to claim 15, wherein the first filler material layer comprises a block copolymer including at least one material selected from a group consisting of hydrophobic aromatic hydrocarbon, hydrophobic aliphatic unsaturation hydrocarbon, hydrophilic aliphatic hydrocarbon, hydrophilic aromatic hydrocarbon, hydrophobic siloxane, and metal complex.

20. The method according to claim 15, wherein the first filler material layer comprises a block copolymer including at least one material selected from a group consisting of polymethylmethacrylate, polystyrene, polyfluorene, polybutadiene, polyisoprene, polyvinyl alcohol, polyethylene glycol, polyvinyl pyridine, polystyrene sulfonic acid, poly dimethylsiloxane, and poly ferrocene.