METHOD AND SYSTEM FOR SEALING A SUBSTRATE

• US 20100072595A1
• Filed: 11/30/2009
• Published: 03/25/2010
• 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 D.
• Granted Patent: US 7,935,555 B2
• Time in Patent Office: Days
• US Class Current: 257/678
• 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 to 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. An electronic device comprising a micro-electromechanical systems (MEMS) device, a metal layer, a mask, a metal seal layer, and a backplane prepared by a process comprising the steps of:

providing a MEMS device on a substrate;

depositing a metal layer on the substrate;

forming a mask with one or more perimeter cavities over the metal layer;

depositing one or more metal seal layers in the one or more perimeter cavities, thereby forming a seal proximate to the perimeter of the MEMS device; and

joining a backplane to the seal.

2. The electronic device of claim 1, wherein the MEMS device comprises an interferometric modulator.

3. The electronic device of claim 1 further prepared by a process comprising removing the mask, and the metal layer, at areas not covered by the one or more metal seal layers, thereby forming a sealant wall.

4. The electronic device of claim 3 further prepared by a process comprising removing a sacrificial layer from the MEMS device.

5. The electronic device of claim 1 further prepared by a process comprising applying a desiccant between the MEMS device and the backplane.

6. The electronic device of claim 5, wherein the desiccant is selected from the group consisting of zeolites, molecular sieves, surface adsorbents, bulk adsorbents and chemical reactants.

7. The electronic device of claim 1, wherein the desiccant comprises a powder.

8. The electronic device of claim 1, wherein the seal proximate to the perimeter of the MEMS device comprises a non-hermetic seal.

9. The electronic device of claim 8, wherein the non-hermetic seal is selected from the group consisting of conventional epoxy-based adhesive, polyisobutylene, butyl rubber, o-rings, polyurethane, thin film metal weld, liquid spin-on glass, solder, polymers and plastic.

10. The electronic device of claim 1, wherein the seal proximate to the perimeter of the MEMS device comprises a substantially hermetic seal.

11. The electronic device of claim 10, wherein the substantially hermetic seal comprises metal.

12. The electronic device of claim 1 further prepared by depositing an insulator layer on the substrate before depositing the metal layer.

13. The electronic device of claim 12, wherein the depositing the insulator layer comprises depositing the insulator layer to contact the substrate.

14. The electronic device of claim 12, wherein the depositing the insulator layer comprises depositing the insulator layer on at least one layer in contact with the substrate.

15. The electronic device of claim 14, wherein the at least one layer comprises a conductive material.