Gas pressure gage

• US 4,747,311 A
• Filed: 03/10/1987
• Issued: 05/31/1988
• Est. Priority Date: 03/20/1986
• Status: Expired due to Term

• Current Assignee: SII NanoTechnology Inc. (Hitachi High- Tech Corporation)
• Original Assignee: Seiko Instruments Incorporated (Seiko Group)
• Inventors: Hojoh, Hisao
• Primary Examiner(s): WOODIEL, DONALD
• Application Number:
  US07/024,370
• Time in Patent Office: 448 Days
• Field of Search: 73/704, 73/702, 73/714, 73/753, 73/711, 73/709, 73/756, 324/460, 324/461, 324/462, 324/463
• US Class Current: 73/702
• CPC Class Codes: G01L 21/00 Vacuum gauges
• CPC Class Codes: G01L 21/30 by making use of ionisation effects
• CPC Class Codes: G01L 21/32 using electric discharge tubes with thermionic cathodes
• CPC Class Codes: G01L 9/0022 of a piezoelectric element

Abstract

Regarding a gas pressure gage for measuring a gas pressure in a vacuum chamber of a semiconductor element manufacturing apparatus, or the like, the present invention has made it possible to attain a small-sized and unitary gas pressure gage and to implement a thorough measurement of gas pressure from the atmospheric pressure to a high vacuum of about 10^-10 Torr, by mounting both a mechanical vibrator type pressure gage and an ionization type pressure gage on a flange provided for fitting a chamber and by providing a control circuit for making the former gage operate in a low-vacuum region and the latter in a high-vacuum region.

Claims

1. A gas pressure gage wherein a pressure gage using a mechanical vibrator driven by an electric field or a magnetic field and an ionization-type pressure gage are incorporated in a common flange and which is provided with a control circuit for making the pressure gage using the mechanical vibrator operate in a low-vacuum region and the ionization-type pressure gage in a highvacuum region.

2. A gas pressure gage according to claim 1 wherein the mechanical vibrator is a quartz vibrator.

3. A gas pressure gage according to claim 1 wherein the ionization-type pressure gage is a Bayard-Alpert gage.