Micromirror manufacturing method

• US 7,901,969 B2
• Filed: 12/24/2007
• Issued: 03/08/2011
• Est. Priority Date: 12/26/2006
• Status: Active Grant

• Current Assignee: Ignite USA (Ignite)
• Original Assignee: Olympus Corporation, Silicon Quest Kabushiki-Kaisha
• Inventors: Ichikawa, Hirotoshi, Ishii, Fusao
• Primary Examiner(s): Picardat; Kevin M
• Application Number:
  US12/004,598
• Publication Number:
  US 20090149004A1
• Time in Patent Office: 1,170 Days
• Field of Search: 438 50- 53, 438458-465
• US Class Current: 438/50
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81C 3/002 Aligning microparts
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H01L 2924/1461 MEMS

Abstract

A micro-mirror manufacturing method for dividing a plurality of micro-mirror devices each having at least one mirror, formed on a semiconductor wafer into individual micro-mirror devices can be provided. The manufacturing method comprises a step of depositing an inorganic protection layer on the mirror before separating the micro-mirror devices from the wafer and a step of removing the inorganic protection layer after separating the micro-mirror devices from the wafer.

Claims

1. A method for manufacturing a plurality of micro-electrical-mechanical-systems(MEMS) devices on a semiconductor wafer wherein each having at least one movable element comprising:

depositing and patterning a first sacrificial layer into a plurality of support structures followed by forming a depositing and patterning a plurality of hinges along a vertical and horizontal sidewalls of said support structures;

depositing a second sacrificial layer covering over the hinges and said support structures followed by etching back said second sacrificial layer back to a top surface of said hinges;

depositing and patterning a reflective surface on top of the second sacrificial layer contacting the top surface of said hinge thus forming a plurality of movable elements; and

depositing an inorganic protection layer on top of the reflective surface and the second sacrificial layer covering over the movable elements followed by dicing the semiconductor wafer for separating the semiconductor wafer into the plurality of MEMS devices from the wafer; and

removing the inorganic protection layer and etching off the first and second sacrificial layers after dicing and separating the semiconductor wafer into the MEMS devices.

2. The micro-electrical-mechanical-systems(MEMS) manufacturing method according to claim 1, wherein:

the step of depositing the inorganic protection layer is a step of depositing a silicon compound as the inorganic protection layer.

3. The micro-electrical-mechanical-systems(MEMS) manufacturing method according to claim 1, wherein:

the step of depositing the inorganic protection layer is a step of depositing a silicon dioxide (SiO₂) as the inorganic protection layer.

4. The micro-electrical-mechanical-systems(MEMS) manufacturing method according to claim 1, wherein:

the step of depositing the inorganic protection layer is a step of depositing a silicon carbide (SiC) as the inorganic protection layer.

5. The micro-electrical-mechanical-systems(MEMS) manufacturing method according to claim 1, wherein:

the step of removing the inorganic protection layer is a step of dry etching to remove the inorganic protection layer.

6. The micro-electrical-mechanical-systems(MEMS) manufacturing method according to claim 1, wherein:

the step of depositing and patterning the first sacrificial layer is a step of depositing and patterning an inorganic layer into said plurality of support structures for providing the vertical sidewall to extend above the semiconductor wafer as the hinges to support the movable elements.

7. The micro-electrical-mechanical-systems(MEMS) manufacturing method according to claim 1, wherein:

the step of depositing the inorganic protection layer is a step of depositing the same material as the first sacrificial layer.

8. The method according to claim 1, further comprising:

applying an anti-stiction process to the MEMS devices to prevent the moveable elements from sticting to a contacting surface.

9. The method according to claim 1, further comprising:

forming at least one auxiliary member for each of said MEMS devices as an alignment reference before dicing and separating the semiconductor wafer into the MEMS devices.

10. The method according to claim 1, further comprising:

forming an opening in a back surface of the semiconductor wafer for each of the MEMS device as a relative position reference for packaging the MEMS device before dicing and separating the semiconductor wafer into the MEMS devices.

11. The method according to claim 1, further comprising:

packaging each of said MEMS devices into a is micro-mirror device.

12. A method for manufacturing a plurality of micro-electrical-mechanical-systems(MEMS) devices on a semiconductor wafer wherein each having at least one movable element comprising:

depositing a first inorganic sacrificial layer on the substrate and patterning the first inorganic sacrificial layer into a plurality of support structures followed by depositing a silicon layer and pattering the silicon layer a plurality of hinges along a vertical and horizontal sidewalls of said support structures by patterning each of said hinges to have a horizontal portion attached to a top surface of the semiconductor wafer and a horizontal portion as a platform for supporting a reflective surface thereon; and

depositing a second inorganic sacrificial layer on the hinges and said first inorganic sacrificial layer.

13. The method according to claim 12, wherein:

the step of depositing the second sacrificial layer is a step of depositing the second sacrificial layer with the same material as a said first sacrificial layer.

14. The method according to claim 12, wherein:

the step of depositing the first sacrificial layer is a step of depositing a silicon dioxide (SiO₂) as the first sacrificial layer.

15. The method according to claim 12, further comprising:

removing an inorganic protection layer on top of the second sacrificial layer and etching off the first and second sacrificial layers after dicing and separating the semiconductor wafer into the MEMS devices.

16. The method according to claim 12, further comprising:

packaging each of said MEMS devices into a micro-mirror device.

17. The method according to claim 12, further comprising

simultaneously removing an inorganic protection layer on top of the second sacrificial layer by etching off the inorganic protection layer, the first and second sacrificial layers after dicing and separating the semiconductor wafer into the MEMS devices.

18. The method according to claim 12, further comprising:

performing an inspection on said movable elements before dicing and separating the semiconductor substrate into the MEMS devices by inspecting through the first and second sacrificial layer formed as transparent sacrificial layers.