Process for wafer level treatment to reduce stiction and passivate micromachined surfaces and compounds used therefor

• US 6,674,140 B2
• Filed: 01/29/2001
• Issued: 01/06/2004
• Est. Priority Date: 02/01/2000
• Status: Expired due to Term

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Martin, John R.
• Primary Examiner(s): JACKSON JR, JEROME
• Application Number:
  US09/771,872
• Publication Number:
  US 20010034076A1
• Time in Patent Office: 1,072 Days
• Field of Search: 257/415, 257/642
• US Class Current: 257/415
• CPC Class Codes: B81B 3/0005 Anti-stiction coatings
• CPC Class Codes: B81C 1/0096 For avoiding stiction when the device is in use, i.e. after manufacture has been completed
• CPC Class Codes: B81C 2201/0176 Chemical vapour Deposition
• CPC Class Codes: B81C 2201/112 Depositing an anti-stiction or passivation coating, e.g. on the elastic or moving parts
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• CPC Class Codes: H01L 21/02216 the compound being a molecule comprising at least one silicon-oxygen bond and the compound having hydrogen or an organic group attached to the silicon or oxygen, e.g. a siloxane
• CPC Class Codes: H01L 21/02263 deposition from the gas or vapour phase
• CPC Class Codes: H01L 21/3122 layers comprising polysiloxane compounds
• CPC Class Codes: H01L 2224/05624 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48624 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 24/05 of an individual bonding area
• CPC Class Codes: H01L 24/45 of an individual wire connector
• 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 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/10253 Silicon [Si]
• CPC Class Codes: H01L 2924/12044 : OLED
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/16152 : Cap comprising a cavity for hosting the device, e.g. U-shaped cap
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding

Abstract

This invention discloses a process for forming durable anti-stiction surfaces on micromachined structures while they are still in wafer form (i.e., before they are separated into discrete devices for assembly into packages). This process involves the vapor deposition of a material to create a low stiction surface. It also discloses chemicals which are effective in imparting an anti-stiction property to the chip. These include polyphenylsiloxanes, silanol terminated phenylsiloxanes and similar materials.

Claims

1. A chip having anti-stiction properties, said chip comprising:

a substrate having a micromachined structure fabricated on one surface thereof; and

a layer of a linear organo silicon compound disposed on said micromachined structure, wherein the organic substituents on the silicon atom of said silicon compound are phenyl substituents.

2. The chip of claim 1 wherein said organo silicon compound is selected from the group consisting of diphenylsilanediol, a linear diphenyl siloxane, hexaphenyldisiloxane, silanol-terminated diphenylsiloxane, silanol-terminated polydiphenylsiloxane, tetraphenyldisiloxanediol, triphenyl silane, triphenylsilanol, and mixtures thereof.

3. The chip of claim 1, wherein said micromachined structure comprises at least one inertial sensor.

4. The chip of claim 3 wherein said inertial sensor is an accelerometer or a gyroscope.

5. The chip of claim 1, wherein said micromachined structure includes at least one mirror.

6. The chip off claim 5, wherein said micromachined structure comprises an optical interferometer.

7. A chip of claim 1, wherein said micromachined structure includes at least one element that is movable in response to an imposed electrostatic field.

8. The chip of claim 1, wherein said micromachined structure includes at least one element that is movable in response to an imposed magnetic field.

9. The chip of claim 1, wherein said layer has a thickness generally in the range between 5-100 Angstroms.

11. The chip of claim 1, wherein said linear organo silicon compound is a vapor.

10. A chip having anti-stiction properties, said chip comprising:

a substrate having a micromachined structure fabricated on one surface thereof; and

a layer of an organo silicon compound disposed on said micromachined structure, wherein said organo silicon compound is selected from the group consisting of phenylsilanols and phenylsilanes having at least one hydrogen substituent, and wherein the organic substituents on the silicon atom of said silicon compound are phenyl substituents.

12. The chip of claim 10, wherein said linear organo silicon compound is a vapor.