Integrated sensor having plurality of released beams for sensing acceleration and associated methods

• US 6,750,775 B2
• Filed: 02/26/2001
• Issued: 06/15/2004
• Est. Priority Date: 10/24/1997
• Status: Expired due to Term

• Current Assignee: STMicroelectronics Incorporated (STMicroelectronics NV)
• Original Assignee: STMicroelectronics Incorporated (STMicroelectronics NV)
• Inventors: Chan, Tsiu Chiu, DeSilva, Melvin Joseph
• Primary Examiner(s): Lee, Benjamin C.
• Application Number:
  US09/792,962
• Publication Number:
  US 20020008296A1
• Time in Patent Office: 1,205 Days
• Field of Search: 340/669, 340/683, 340/670, 340/671, 340/687, 340/689, 340/686.1, 340/436, 340/440, 340/540, 735/140.1, 735/141.5, 735/141.6, 735/142.1, 735/142.2, 735/142.3, 735/142.4, 735/142.9, 735/143.6, 735/143.7, 735/143.8, 200/61.45 R, 200/61.48, 200/61.49, 200/61.5, 200/61.51, 200/61.52
• US Class Current: 340/669
• CPC Class Codes: B81B 2201/014 having a cantilever fixed on one side connected to one or more dimples
• 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 2203/0735 Post-CMOS, i.e. forming the micromechanical structure after the CMOS circuit
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/135 by making use of contacts which are actuated by a movable inertial mass
• CPC Class Codes: G01P 15/18 in two or more dimensions

Abstract

An integrated circuit and method are provided for sensing activity such as acceleration in a predetermined direction of movement. The integrated released beam sensor preferably includes a switch detecting circuit region and a sensor switching region connected to and positioned adjacent the switch detecting circuit region. The sensor switching region preferably includes a plurality of floating contacts positioned adjacent and lengthwise extending outwardly from said switch detecting circuit region for defining a plurality of released beams so that each of said plurality of released beams displaces in a predetermined direction responsive to acceleration. The plurality of released beams preferably includes at least two released beams lengthwise extending outwardly from the switch detecting circuit region to different predetermined lengths and at least two released beams lengthwise extending outwardly from the switch detecting circuit region to substantially the same predetermined lengths. The methods of forming an integrated sensor advantageously are preferably compatible with know integrated circuit manufacturing processes, such as for CMOS circuit manufacturing, with only slight variations therefrom.

Claims

1. A method of sensing an activity, the method comprising:

providing a switch detecting circuit region;

providing a first plurality of floating contacts positioned in spaced relation in a normally open position with at least one fixed contact layer, each of the first plurality of floating contacts having substantially the same length;

contacting less than all of the first plurality of floating contacts with the at least one fixed contact layer so as to form a closed switch position;

generating an activity confirmation signal responsive to a majority of the first plurality of floating contacts contacting the at least one fixed contact layer;

providing a second plurality of floating contacts having a different length than the first plurality of contacts;

contacting less than all of the second plurality of floating contacts with the at least one fixed contact layer so as to form a closed switch position; and

generating an activity confirmation signal responsive to a majority of the second plurality of floating contacts contacting the at least one fixed contact layer.