MEMS DEVICE AND FABRICATION METHOD OF THE SAME

• US 20080179988A1
• Filed: 10/16/2007
• Published: 07/31/2008
• Est. Priority Date: 01/25/2007
• Status: Active Grant

• Current Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Original Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Inventors: Cho, Jin-woo, Jeong, Hee-moon, Chang, Seok-mo, Park, Yong-hwa, Kim, Jun-o
• Granted Patent: US 7,800,280 B2
• Time in Patent Office: Days
• US Class Current: 310/309
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 2203/058 Rotation out of a plane parallel to the substrate
• CPC Class Codes: B81B 3/0051 For defining the movement, i.e. structures that guide or limit the movement of an element mechanical arrangements for preventing or damping vibration or shock H01H3/60
• CPC Class Codes: G02B 26/085 the reflecting means being moved or deformed by electromagnetic means
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129
• CPC Class Codes: G02B 26/105 with one or more pivoting mirrors or galvano-mirrors G02B26/101 takes precedence

Abstract

A microelectromechanical systems (MEMS) device includes a frame, an actuator formed on the same layer as the frame and connected to the frame to be capable of performing a relative motion with respect to the frame, and at least one stopper restricting a displacement of the actuator in a direction along the height of the actuator. The MEMS device is fabricated by bonding a second substrate to a first substrate, forming the frame and the actuator by partially removing the first substrate, and forming the at least one stopper by partially removing the second substrate.

Claims

1. A microelectromechanical systems (MEMS) device comprising:

a frame;

an actuator formed on a same layer as the frame and connected to the frame to be capable of performing a relative motion with respect to the frame; and

at least one stopper which restricts a displacement of the actuator in a direction along a height of the actuator.

2. The MEMS device of claim 1, wherein the at least one stopper comprises an ascending restriction stopper which restricts an upward displacement of the actuator and a descending restriction stopper which restricts a downward displacement of the actuator.

3. The MEMS device of claim 2, wherein the ascending restriction stopper is fixed to the frame, and includes an end portion that overlaps the actuator by being separated a predetermined distance from the actuator when there is no displacement of the actuator.

4. The MEMS device of claim 2, wherein the descending restriction stopper is fixed to the actuator, and includes an end portion that overlaps the frame by being separated a predetermined distance from the frame when there is no displacement of the actuator.

5. The MEMS device of claim 1, further comprising a stage fixed to the actuator.

6. The MEMS device of claim 5, wherein the at least one stopper is formed on a same layer as the stage.

7. The MEMS device of claim 5, further comprising a separation column provided between the actuator and the stage to restrict deformation of the stage due to thermal deformation of the actuator.

8. The MEMS device of claim 7, wherein a circular opening portion to restrict thermal transfer between the stage and the actuator is formed in a peripheral area of an area where the actuator is coupled to the separation column.

9. The MEMS device of claim 1, wherein the actuator is connected to the frame to be capable of pivoting with respect to the frame.

10. The MEMS device of claim 9, further comprising an electrostatic capacity sensor which detects an amount of pivot of the actuator.

11. The MEMS device of claim 10, wherein the electrostatic capacity sensor comprises:

a drive comb which pivots with the actuator according to the pivoting of the actuator; and

a fixed comb which is fixedly supported at a complementary position where the fixed comb is engaged with the drive comb, and forms an overlapping surface whose area changes according to the pivoting of the drive comb.

12. The MEMS device of claim 1, wherein the actuator comprises:

an external variable portion connected to the frame to be capable of pivoting about a first pivot axis with respect to the frame; and

an internal variable portion located inside the external variable portion to be capable of pivoting about a second pivot axis with respect to the external variable portion, the second pivot axis being perpendicular to the first pivot axis,

wherein the stopper restricts a displacement of the external variable portion in the direction along the height of the actuator.

13. The MEMS device of claim 1, further comprising:

a drive coil wound around a peripheral portion of the actuator; and

at least one magnet which forms a magnetic field that crosses current flowing in the drive coil.

14. A method of fabricating a microelectromechanical systems (MEMS) device, the method comprising:

bonding a second substrate to a first substrate;

forming a frame and an actuator connected to the frame to be capable of performing a relative motion with respect to the frame by partially removing the first substrate; and

forming at least one stopper which restricts a displacement of the actuator in a direction along the height of the actuator by partially removing the second substrate.

15. The method of claim 14, wherein the first and second substrates are formed of silicon.

16. The method of claim 14, wherein the forming of an actuator comprises forming the actuator connected to the frame to be capable of pivoting with respect to the frame.

17. The method of claim 14, wherein the forming of at least one stopper comprises forming an ascending restriction stopper which restricts an upward displacement of the actuator and a descending restriction stopper which restricts a downward displacement of the actuator.

18. The method of claim 14, further comprising partially etching a lower surface of the second substrate before bonding the first substrate and the second substrate to allow an end portion of the at least one stopper to be separated from the first substrate.

19. The method of claim 14, further comprising forming a stage fixed to the actuator by partially removing the second substrate.

20. The method of claim 19, further comprising partially etching a lower surface of the second substrate before bonding the first and second substrates to form a separation column provided between the actuator and the stage.

21. The method of claim 14, further comprising partially etching an upper surface of the first substrate before bonding the first and second substrates to allow an end portion of the stopper to be separated from the first substrate.

22. The method of claim 14, wherein the forming of the actuator comprises:

forming an external variable portion connected to the frame to be capable of pivoting about a first pivot axis with respect to the frame; and

forming an internal variable portion located inside the external variable portion to be capable of pivoting about a second pivot axis with respect to the external variable portion, the second pivot axis being perpendicular to the first pivot axis.

23. The method of claim 14, further comprising:

forming a drive coil wound around a peripheral portion of the actuator; and

arranging at least one magnet which forms a magnetic field that crosses current flowing in the drive coil.

24. The method of claim 23, wherein the forming of the drive coil comprises:

forming at least one drive coil groove by etching a lower surface of the first substrate; and

depositing metal in the at least one drive coil groove.