Method and system for sealing a substrate

• US 7,642,127 B2
• Filed: 07/17/2007
• Issued: 01/05/2010
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Floyd, Philip
• Primary Examiner(s): Nhu; David
• Application Number:
  US11/779,185
• Publication Number:
  US 20070298541A1
• Time in Patent Office: 903 Days
• Field of Search: 438/30, 438/106, 438/553, 438/680, 438/723, 438/743, 438/756, 438/683, 438/648, 438/656, 438/780
• US Class Current: 438/106
• CPC Class Codes: B81C 1/00269 Bonding of solid lids or wafers to the substrate
• CPC Class Codes: B81C 2203/019 characterised by the material or arrangement of seals between parts
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26

Abstract

A method of sealing a microelectromechanical system (MEMS) device from ambient conditions is described, wherein the MEMS device is formed on a substrate and a substantially hermetic seal is formed as part of the MEMS device manufacturing process. The method comprises forming a metal seal on the substrate proximate a perimeter of the MEMS device using a method such as photolithography. The metal seal is formed on the substrate while the MEMS device retains a sacrificial layer between conductive members of MEMS elements, and the sacrificial layer is removed after formation of the seal and prior to attachment of a backplane.

Claims

1. A method of sealing a microelectromechanical system (“

MEMS”

) device from ambient conditions, comprising;

providing a substrate comprising a MEMS device;

forming a metal seal on the substrate, wherein forming the metal seal comprises forming an insulator layer on the substrate, and forming a metal sealant wall on the insulator layer, wherein forming the metal seal and the metal sealant wall further comprise depositing one or more metal layers over the insulator layer; and

attaching a backplane to the metal seal so as to seal the MEMS device from ambient conditions.

2. The method of sealing a MEMS device from ambient conditions according to claim 1, wherein the one or metal layers comprise at least one of a metal seed layer and an adhesion layer.

3. The method of sealing a MEMS device from ambient conditions according to claim 1, wherein attaching the backplane comprises soldering.

4. The method of sealing a MEMS device from ambient conditions according to claim 1, wherein the MEMS device comprises a sacrificial layer, and wherein the method further comprises removing the sacrificial layer from the MEMS device after forming the metal seal.

5. The method of sealing a MEMS device from ambient conditions according to claim 1, wherein the MEMS device comprises an interferometric modulator.

6. The method of sealing a MEMS device from ambient conditions according to claim 1, wherein forming the metal seal comprises electroplating.

7. The method of sealing a MEMS device from ambient conditions according to claim 1, wherein the substrate is a transparent substrate.

8. The method of sealing a MEMS device from ambient conditions according to claim 1, wherein the MEMS device comprises an array of interferometric modulators.

9. A method of making a microelectromechanical system (“

MEMS”

) device, comprising;

providing a MEMS device formed on a substrate;

depositing an insulator on the substrate;

depositing one or more metal layers on the insulator;

forming a sealant wall proximate to a perimeter of the MEMS device and over the insulator, wherein forming a sealant wall comprises;

providing a mask layer over the one or more metal layers; and

patterning the mask layer to define one or more cavities; and

attaching a backplane to the sealant wall.

10. The method of making a MEMS device according to claim 9, wherein the MEMS device comprises a sacrificial layer.

11. The method of making a MEMS device according to claim 10 further comprising removing the sacrificial layer from the MEMS device prior to attaching the backplane.

12. The method of making a MEMS device according to claim 9 further comprising forming one or more metal seal layers in the one or more cavities, thereby forming a hermetic seal proximate to a perimeter of the MEMS device.

13. The method of making a MEMS device according to claim 9 further comprising removing the mask layer, the one or more metal layers and the insulating layer.

14. The method of making a MEMS device according to claim 9, wherein forming one or more metal seal layers comprises electroplating over the mask layer.

15. The method of making a MEMS device according to claim 9, further comprising forming one or more adhesion metal layers over the one or more metal seal layers, wherein the one or more adhesion metal layers are configured for attachment to the backplane.

16. The method of making a MEMS device according to claim 15, wherein the one or more adhesion layers comprises a solder.

17. The method of making a MEMS device according to claim 9, wherein the mask comprises photoresist.

18. The method of making a MEMS device according to claim 9, wherein the one or metal layers deposited over the insulator layer comprise at least one of a metal seed layer and an adhesion layer.

19. The method of making a MEMS device according to claim 9, wherein the backplane comprises a pre-deposited adhesion layer configured to adhere to the sealant wall.

20. The method of making a MEMS device according to claim 9, wherein attaching the backplane to the sealant wall comprises soldering.

21. The method of making a MEMS device according to claim 9, wherein the backplane comprises an adhesion layer and a solder layer proximate to an area for attachment to the sealant wall.

22. The method of making a MEMS device according to claim 21, wherein the adhesion layer comprises metal.

23. The method of making a MEMS device according to claim 9, wherein the insulator contacts the substrate.

24. The method of making a MEMS device according to claim 9, wherein the insulator is disposed on at least one layer in contact with the substrate.

25. The method of making a MEMS device according to claim 24, wherein the at least one layer comprises a conductive lead.

26. The method of making a MEMS device according to claim 17, wherein forming the mask comprises the use of UV light.

27. A method of sealing a microelectromechanical system (“

MEMS”

) device from ambient conditions, comprising;

providing a substrate comprising a MEMS device;

forming a metal seal on the substrate, wherein forming the metal seal comprises forming an insulator layer on the substrate, and forming a metal sealant wall on the insulator layer, wherein the MEMS device comprises a sacrificial layer, and wherein the method further comprises removing the sacrificial layer from the MEMS device after forming the metal seal; and

attaching a backplane to the metal seal so as to seal the MEMS device from ambient conditions.

28. The method of sealing a MEMS device from ambient conditions according to claim 27, wherein forming the metal seal and metal sealant wall further comprises depositing one or more metal layers over the insulator layer.

29. The method of sealing a MEMS device from ambient conditions according to claim 28, wherein the one or metal layers comprise at least one of a metal seed layer and an adhesion layer.

30. The method of sealing a MEMS device from ambient conditions according to claim 27, wherein attaching the backplane comprises soldering.

31. The method of sealing a MEMS device from ambient conditions according to claim 27, wherein the MEMS device comprises an interferometric modulator.

32. The method of sealing a MEMS device from ambient conditions according to claim 27, wherein forming the metal seal comprises electroplating.

33. The method of sealing a MEMS device from ambient conditions according to claim 27, wherein the substrate is a transparent substrate.

34. The method of sealing a MEMS device from ambient conditions according to claim 27, wherein the MEMS device comprises an array of interferometric modulators.