Micro-machining minute hollow using native oxide membrane

• US 5,909,048 A
• Filed: 04/14/1997
• Issued: 06/01/1999
• Est. Priority Date: 12/27/1993
• Status: Expired due to Term

• Current Assignee: Fujitsu Semiconductor Limited (Fujitsu Limited)
• Original Assignee: Fujitsu Limited
• Inventors: Sugino, Rinji
• Primary Examiner(s): GUAY, JOHN FRANCIS
• Application Number:
  US08/837,107
• Time in Patent Office: 778 Days
• Field of Search: 257/410, 257/414, 257/415, 257/417, 257/418, 257/419, 257/522, 257/622, 257/394, 257/467, 438/422, 313/325
• US Class Current: 257/522
• CPC Class Codes: B81B 2203/0315 Cavities
• CPC Class Codes: B81C 1/00047 Cavities
• CPC Class Codes: B81C 1/00626 Processes for achieving a desired geometry not provided for in groups B81C1/00563 - B81C1/00619
• CPC Class Codes: B81C 2201/0115 Porous silicon
• CPC Class Codes: H01J 21/105 with microengineered cathode and control electrodes, e.g. Spindt-type
• CPC Class Codes: H01L 21/32137 of silicon-containing layers

Abstract

A native oxide film is formed on the surface of a silicon substrate. The native oxide film has at least island-shaped imperfect SiO₂ regions not formed with a perfect SiO₂ film. Before the native oxide film is formed, a mask layer having a necessary opening is formed over the silicon substrate, according to necessity. The silicon substrate is etched in a vapor phase via the imperfect SiO₂ regions of the native oxide film to form a hollow under the native oxide film at least at a partial region thereof. An upper film is formed on the native oxide film to cover and close the imperfect SiO₂ regions. In this manner, a minute hollow can be formed in the silicon substrate with good controllability.

Claims

1. A micro device with a minute hollow comprising:

an underlying substrate having a concave formed in the surface of said substrate at a predetermined region and having an opening at a surface of the underlying substrate; and

a lid member covering the opening of said concave, said lid member including a porous film having a number of randomly distributed fine holes formed at least in a partial region thereof and an upper film formed on said porous film, wherein said porous film and said upper film collectively seal said opening.

2. A micro device according to claim 1, wherein said porous film comprises a native oxide film.

3. A micro device with a minute hollow comprising:

an underlying substrate having a surface resistant to etching;

a hollow member formed on said underlying substrate and containing a hollow therein, said hollow being covered with a porous film having a number of randomly distributed fine holes at least at a partial region thereof; and

a cover film formed at least on said porous film to cover the fine holes,

wherein said porous film and said cover film collectively seal said hollow.

4. A micro device according to claim 3, wherein said porous film comprises a native oxide film.

5. A micro device with a minute hollow comprising:

a silicon substrate having a recess formed in a surface of said silicon substrate at a predetermined region, having an opening at the surface and extending in a first direction;

a native oxide film having island-shaped fine holes and formed on the opening of said recess at least at a partial region thereof;

an intermediate film resistant to etching formed on said substrate and said native oxide film closing the fine holes;

a hollow formed in said intermediate film, extending in a second direction, and crossing said recess, said hollow being surrounded by an exposed surface resistant to etching at the side wall thereof and by another native oxide film having island-shaped fine holes at the top wall thereof;

an upper film formed at least on said other native oxide film and closing the fine holes; and

a junction hole formed in said intermediate film and said native oxide film at the cross area between said recess and said hollow.