Micromachined capsules having porous membranes and bulk supports

• US 5,770,076 A
• Filed: 06/07/1995
• Issued: 06/23/1998
• Est. Priority Date: 03/07/1994
• Status: Expired due to Term

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Ferrari, Mauro, Chu, Wen-Hwa
• Primary Examiner(s): Drodge, Joseph W.
• Application Number:
  US08/482,237
• Time in Patent Office: 1,112 Days
• Field of Search: 210/321.6, 210/500.22, 210/500.26, 210/490, 604/890.1, 604/891.1, 604/892.2, 424/421, 424/424, 424/425, 424/451, 424/456, 216/56, 216/2
• US Class Current: 210/490
• 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 2325/04 Characteristic thickness
• 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 67/0034 by micromachining techniques, e.g. using masking and etching steps, photolithography
• 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 69/02 characterised by their properties
• CPC Class Codes: B01D 69/1216 Three or more layers
• CPC Class Codes: B01D 71/0213 Silicon
• CPC Class Codes: B01J 13/02 Making microcapsules or microballoons for medical preparations A61K9/50
• CPC Class Codes: B81B 2201/10 Microfilters, e.g. for gas or fluids
• CPC Class Codes: B81B 3/007 For controlling stiffness, e.g. ribs
• CPC Class Codes: B81C 1/00087 Holes
• CPC Class Codes: B81C 2201/014 by depositing an etch stop layer, e.g. silicon nitride, silicon oxide, metal
• CPC Class Codes: C04B 41/4582 Porous coatings, e.g. coating containing porous fillers
• 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: G03F 7/0015 : Production of aperture devices, microporous systems or stamps

Abstract

Surface micromachining and bulk micromachining are employed for realizing a porous membrane with bulk support for a microparticle fiter. The filter is sufficiently sturdy to allow for easy handling. It may be used as a diffusion barrier and under high pressures. The disclosed fabrication method is simple, reliable, and integrated-circuit compatible, and thus amenable to mass production. Electronic circuitry may be integrated on the filter surface, as may be desired for several purposes, such as fluid characterization, filter self-cleaning, or charging of the filter surfaces. Methods are shown for the realization of biological containment capsules based on this microfilter.

Claims

1. A microfabricated containment capsule, comprising:

at least one bulk substrate, said at least one bulk substrate delimiting a cavity having a boundary, a first portion of said boundary constituting an inner wall of a solid portion of said at least one bulk substrate; and

at a second portion of said boundary, a membrane having at least one porous area with controlled pores and rib members to provide additional structural support to said at least one porous area, providing a selective molecular barrier between an interior and an exterior of said containment capsule.