Vapor deposition of anti-stiction layer for micromechanical devices

• US 7,927,423 B1
• Filed: 05/25/2005
• Issued: 04/19/2011
• 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): Kackar; Ram N
• Assistant Examiner(s): Chandra; Satish
• Application Number:
  US11/136,922
• Time in Patent Office: 2,155 Days
• Field of Search: 210/294, 210/321.6, 210/322.2, 210/323.2, 210/324, 118/715
• US Class Current: 118/715
• 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 vapor deposition system for depositing Ultra-thin passivation layers on the surfaces of micromechanical devices, comprising:

a deposition chamber having walls defining a sealed enclosure for processing micromechanical devices contained therein, the chamber including an inlet for receiving gas and an outlet for exhausting gas;

a source of vaporized passivants provided in controlled fluid communication with the inlet for introducing the vaporized passivants in a gas stream into the chamber for deposition on the surfaces of the micromechanical devices;

a vacuum pump in fluid communication with the outlet for pulling a partial vacuum in the chamber and drawing the vaporized passivants though the chamber; and

a filter-diffuser device connected to the inlet, the filter-diffuser device having multiple filters for filtering vapor after flowing through the inlet and allowing the passivants to flow through into the chamber, the filters being arranged to uniformly distribute the vapor flow into the chamber, each filter having filter walls formed of a porous metal,

wherein the passivant is perfluordecanoic acid (PFDA) and the filters have pores that allow individual PFDA molecules to flow through the filter walls but that filter out larger PFDA particles,

wherein the filter-diffuser device includes a manifold having a cylindrical body portion, wherein the filters are attached to the periphery of the body portion and extend radially outward from the body portion.

2. The system of claim 1 wherein the porous metal of the filters consists essentially of stainless steel.

3. The system of claim 1, wherein the filter walls of each filter 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.