Method for fabrication of high vertical aspect ratio thin film structures

• US 5,660,680 A
• Filed: 03/07/1994
• Issued: 08/26/1997
• Est. Priority Date: 03/07/1994
• Status: Expired due to Term

• Current Assignee: Ob Realty, LLC
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Keller, Christopher G.
• Primary Examiner(s): POWELL, WILLIAM A
• Application Number:
  US08/207,459
• Time in Patent Office: 1,268 Days
• Field of Search: 156/633.1, 156/643.1, 156/636.1, 156/645.1, 156/653.1, 156/657.1, 156/659.11, 156/662.1, 204/192.37, 437/86, 437/78, 437/79, 437/228, 437/233, 437/238, 437/927, 437/974, 216/2, 216/67, 216/66
• US Class Current: 438/50
• CPC Class Codes: A61K 9/0024 Solid, semi-solid or solidifying implants, which are implanted or injected in body tissue compositions for intravenous administration, normal injectable solutions or dispersions for, e.g. subcutaneous administration A61K9/0019; brain implants A61K9/0085; (coated) prostheses, catheters or stents A61L
• CPC Class Codes: A61K 9/0097 Micromachined devices; Microelectromechanical systems [MEMS]; Devices obtained by lithographic treatment of silicon; Devices comprising chips intradermal microneedle arrays A61K9/0021; MEMS in general B81B7/02
• CPC Class Codes: B01D 2323/24 Use of template or surface directing agents [SDA]
• CPC Class Codes: B01D 2325/04 Characteristic thickness
• CPC Class Codes: B01D 2325/08 Patterned membranes
• CPC Class Codes: B01D 39/1692 Other shaped material, e.g. perforated or porous sheets
• CPC Class Codes: B01D 39/20 of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires porous ceramic material C04B38/00 ; sintering metals C22C1/04; making porous sintered metal bodies B22F3/10, honeycomb filters B01D46/2418, materials used for filtering exhaust gases of an internal combustion engine F01N3/022, ceramic honeycomb structures C04B38/0006
• CPC Class Codes: B01D 67/0058 by selective elimination of components, e.g. by leaching
• CPC Class Codes: B01D 67/0062 by micromachining techniques, e.g. using masking and etching steps, photolithography
• CPC Class Codes: B01D 67/0072 by deposition from the gaseous phase, e.g. sputtering, CVD, PVD
• CPC Class Codes: B01D 67/0083 Thermal after-treatment
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 69/12 Composite membranes; Ultra-thin membranes
• CPC Class Codes: B01D 71/02 Inorganic material
• CPC Class Codes: B01D 71/0213 Silicon
• CPC Class Codes: B81B 1/002 Holes characterised by their shape, in either longitudinal or sectional plane
• CPC Class Codes: B81B 1/004 Through-holes, i.e. extending from one face to the other face of the wafer
• CPC Class Codes: B81C 1/00246 Monolithic integration, i.e. micromechanical structure and electronic processing unit are integrated on the same substrate
• CPC Class Codes: B81C 2201/032 LIGA process
• CPC Class Codes: B81C 2203/0728 Pre-CMOS, i.e. forming the micromechanical structure before the CMOS circuit
• CPC Class Codes: B81C 99/0085 : using moulds and master templates, e.g. for hot-embossing
• CPC Class Codes: C23C 16/01 : on temporary substrates, e.g. substrates subsequently removed by etching
• CPC Class Codes: G03F 7/00 : Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor using photoresist structures for special production processes, see the relevant places, e.g. B44C, H01L, e.g. H01L21/00, H05K
• CPC Class Codes: Y10T 428/131 : Glass, ceramic, or sintered, fused, fired, or calcined metal oxide or metal carbide containing [e.g., porcelain, brick, cement, etc.]
• CPC Class Codes: Y10T 428/24149 : Honeycomb-like
• CPC Class Codes: Y10T 428/2457 : Parallel ribs and/or grooves
• CPC Class Codes: Y10T 428/24744 : Longitudinal or transverse tubular cavity or cell

Abstract

This invention relates to the area of microelectromechanical systems in which electronic circuits and mechanical devices are integrated on the same silicon chip. The method taught herein allows the fabrication of thin film structures in excess of 150 microns in height using thin film deposition processes. Wafers may be employed as reusable molds for efficient production of such structures.

Claims