Donald L Hughes

US Patent:

57447250, Apr 28, 1998

Filed:

Jan 8, 1997

Appl. No.:

8/780428

Inventors:

Shiuh-Hui Steven Chen - Lake Zurich IL
Carl Ross - Mundelin IL
Donald L. Hughes - Mesa AZ

Assignee:

Motorola Inc. - Schaumburg IL

International Classification:

H01G 700

US Classification:

73724

Abstract:

A capacitive pressure sensor and method of fabricating the sensor includes providing a layered structure including a second silicon layer (115), a second insulating layer (203, 205) in contact with the second silicon layer (115), a first silicon layer (123) in contact with the second insulating layer (203, 205), a first insulating layer (201) in contact with the first silicon layer (123), and a mask layer (221) in contact with the first insulating layer (201). A major exposed surface (220) of the second silicon layer (115) is provided by mechanically reducing a thickness (210) of the second silicon layer (115) to a predetermined thickness (116). Preferably this is done by grinding and then polishing the second silicon layer (115). In one embodiment a third insulating layer (211) is in contact with the second major surface (220) of the second silicon layer (115). A third silicon layer (101) having a fourth insulating layer (109) forming a perimeter structure (215) positioned above and surrounding a predefined area (114) of the third silicon layer (101).