Vapor deposition of anti-stiction layer for micromechanical devices

• US 9,150,959 B2
• Filed: 04/19/2011
• Issued: 10/06/2015
• Est. Priority Date: 05/25/2005
• Status: Active Grant

• Current Assignee: Kenneth A. Abbott
• Original Assignee: Kenneth A. Abbott
• Inventors: Abbott, Kenneth A.
• Primary Examiner(s): LUND, JEFFRIE ROBERT
• Application Number:
  US13/089,596
• Publication Number:
  US 20120040095A1
• Time in Patent Office: 1,631 Days
• Field of Search: 118/715, 156/345.29, 156/345.33
• US Class Current: 1/1
• CPC Class Codes: B03C 3/017 Combinations of electrostatic separation with other processes, not otherwise provided for
• CPC Class Codes: B05D 1/185 applying monomolecular layers B05D1/204 takes precedence
• CPC Class Codes: B05D 1/60 Deposition of organic layers from vapour phase vapour phase deposition in general C23C14/00, C23C16/00
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 3/0005 Anti-stiction coatings
• CPC Class Codes: B81C 2201/112 Depositing an anti-stiction or passivation coating, e.g. on the elastic or moving parts
• CPC Class Codes: C23C 14/24 Vacuum evaporation
• CPC Class Codes: C23C 14/564 Means for minimising impurities in the coating chamber such as dust, moisture, residual gases
• CPC Class Codes: C23C 16/4402 Reduction of impurities in the source gas
• CPC Class Codes: C23C 16/45568 Porous nozzles
• CPC Class Codes: C23C 16/45578 Elongated nozzles, tubes with holes

Abstract

A vapor deposition system includes a filter-diffuser device connected to a vapor inlet within a vacuum chamber for simultaneously filtering inflowing vapor to remove particulate matter while injecting vapor containing perfluordecanoic acid (PFDA) into the chamber through radially arranged porous metal filters to enable the deposition of a uniform monolayer of PFDA molecules onto the surfaces of a micromechanical device, such as a digital micromirror device.

Claims

1. A method of passivating the surfaces of a micromechanical device, the method comprising:

providing a micromechanical device within a sealed chamber;

pulling a partial vacuum in the chamber;

introducing a vapor consisting of passivants to an inlet to the chamber having a filter-diffuser located thereat, the passivants include perfluordecanoic acid (PFDA);

simultaneously, at the filter-diffuser, filtering the vapor arriving at the inlet and injecting the vapor in multiple directions to uniformly distribute the vapor within the chamber, the vapor being injected through a manifold having a cylindrical body portion coupled to a central cylindrical cavity, wherein filters are attached to the periphery thereof and extend radially outward from the body portion;

flowing the vapor from the manifold to the central cylindrical cavity and radially outward through the filters and into the chamber;

filtering the vapor at the inlet such that pores in the filter walls allow individual PFDA molecules to flow through the filter walls but that filter out larger PFDA particles; and

allowing the vapor to react with the surfaces of the micromechanical device for a predetermined time.

2. The method as recited in claim 1, further comprising reacting the passivant with the surfaces of the micromechanical device to provide an ultra-thin, anti-stiction layer on the surfaces.

3. The method as recited in claim 1, further comprising symmetrically arranging multiple cylindrical filter walls in daisy-wheel fashion around the periphery of the manifold near the chamber inlet.

4. The method as recited in claim 1, further comprising selecting each filter having filter walls formed of a porous metal to include stainless steel.

5. The method as recited in claim 1, further comprising providing filter walls for each filter that include a cylindrical sidewall terminating in an end wall that cooperate to define a cylindrical cavity within the filter, the manifold having an interior cavity in fluid communication with each filter cavity to provide vapor from the inlet to the filter cavities.

6. The method as recited in claim 1, further comprising providing filters having elongated cylindrical walls terminating in threaded ends.

7. The method as recited in claim 6, wherein the threaded ends of the filters screw into threaded sockets at the periphery of the cylindrical body of the manifold.

8. The method as recited in claim 1, wherein providing a micromechanical device within a sealed chamber further comprises providing at least one wafer containing a plurality of chips within a sealed chamber.

9. The method as recited in claim 1, wherein providing a micromechanical device within a sealed chamber further comprises providing a plurality of separated chips within a sealed chamber.

10. A method of passivating the surfaces of a micromechanical device, the method comprising:

providing a micromechanical device within a sealed chamber;

pulling a partial vacuum in the chamber;

introducing a vapor containing passivants to an inlet to the chamber;

simultaneously filtering the vapor arriving at the inlet and injecting the vapor in multiple directions to uniformly distribute the vapor within the chamber, the vapor being injected through a manifold having a cylindrical body portion coupled to a central cylindrical cavity, wherein filters are attached to the periphery thereof and extend radially outward from the body portion;

flowing the vapor from the manifold to the central cylindrical cavity and radially outward through the filters and into the chamber;

filtering the vapor at the inlet such that pores in the filter walls allow individual passivant molecules to flow through the filter walls but that filter out larger passivant particles; and

allowing the vapor to react with the surfaces of the micromechanical device for a predetermined time.

11. The method as recited in claim 10, wherein providing a micromechanical device within a sealed chamber further comprises providing at least one wafer containing a plurality of chips within a sealed chamber.

12. The method as recited in claim 10, wherein providing a micromechanical device within a sealed chamber further comprises providing a plurality of separated chips within a sealed chamber.

13. The method as recited in claim 10, further comprising reacting the passivant with the surfaces of the micromechanical device to provide an ultra-thin, anti-stiction layer on the surfaces.

14. The method as recited in claim 10, further comprising symmetrically arranging multiple cylindrical filter walls in daisy-wheel fashion around the periphery of the manifold near the chamber inlet.

15. The method as recited in claim 10, further comprising selecting each filter having filter walls formed of a porous metal to include stainless steel.

16. The method as recited in claim 10, further comprising providing filter walls for each filter that include a cylindrical sidewall terminating in an end wall that cooperate to define a cylindrical cavity within the filter, the manifold having an interior cavity in fluid communication with each filter cavity to provide vapor from the inlet to the filter cavities.

17. The method as recited in claim 10, further comprising providing filters having elongated cylindrical walls terminating in threaded ends.

18. The method as recited in claim 10, wherein the threaded ends of the filters screw into threaded sockets at the periphery of the cylindrical body of the manifold.

19. A method of passivating the surfaces of a micromechanical device, the method comprising:

providing a micromechanical device within a sealed chamber;

pulling a partial vacuum in the chamber having a filter-diffuser located thereat;

introducing a vapor consisting of passivants to an inlet to the chamber, the vapor being injected through a manifold having a cylindrical body portion coupled to a central cylindrical cavity, wherein filters are attached to the periphery thereof and extend radially outward from the body portion;

flowing the vapor from the manifold to the central cylindrical cavity and radially outward through the filters and into the chamber;

filtering the vapor at the filter-diffuser at the inlet such that pores in the filter walls of the filter-diffuser allow individual passivant molecules to flow through the filter walls but that filter out larger passivant particles; and

allowing the vapor to react with the surfaces of the micromechanical device for a predetermined time.

20. The method as recited in claim 19, wherein providing a micromechanical device within a sealed chamber further comprises providing at least one wafer containing a plurality of chips within a sealed chamber.

21. The method as recited in claim 19, wherein providing a micromechanical device within a sealed chamber further comprises providing a plurality of separated chips within a sealed chamber.