Diaphragm-based-sensors

• US 5,295,395 A
• Filed: 02/07/1991
• Issued: 03/22/1994
• Est. Priority Date: 02/07/1991
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Burns, David W., Akinwande, Akintunde I., Carney, James K., Horning, Robert D., Hocker, G. Benjamin, Stratton, Thomas G., McPherson, Scott A., Saathoff, Deidrich J., Mirza, Amir R.
• Primary Examiner(s): WOODIEL, DONALD
• Application Number:
  US07/652,148
• Time in Patent Office: 1,139 Days
• Field of Search: 73/715-728, 73/182, 92/103 R, 92/103 SD, 338/4, 361/283
• US Class Current: 73/721
• CPC Class Codes: B81B 2201/0292 Sensors not provided for in B81B2201/0207 - B81B2201/0285
• CPC Class Codes: B81B 2203/0127 Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function
• CPC Class Codes: B81C 1/00182 Arrangements of deformable or non-deformable structures, e.g. membrane and cavity for use in a transducer
• CPC Class Codes: G01L 9/0042 Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms details about the integration or bonding of piezoresistor in or on the diaphragm G01L9/0052 and G01L9/0057 respectively
• CPC Class Codes: G01L 9/0073 using a semiconductive diaphragm
• CPC Class Codes: H01L 21/2007 Bonding of semiconductor wafers to insulating substrates or to semiconducting substrates using an intermediate insulating layer H01L21/2011 takes precedence; bonding of semiconductor wafers to semiconductor wafers for junction formation H01L21/187

Abstract

The formation of diaphragms by silicon wafer bonding provides for a structure having at least two such diaphragms with cavities in the wafers to which the diaphragm layer is bonded. Passageways through the wafers provide for communication of a fluid to the diaphragms. In some locations less than all of a plurality of diaphragms may be bonded to only one wafter having a cavity adjacent the diaphragm.

Claims

1. A diaphragm transducer responsive to changes in a relevant fluid or fluids, comprising:

a diaphragm layer bonded on one side by an A surface and bounded on the opposite side by a B surface, an area extending between the A and B surfaces constituting a flexible diaphragm;

an A wafer bounded on one side by an inner surface and bounded on the opposite side by an outer surface, said inner surface bonded to the A surface of the diaphragm layer, said A wafer containing an A cavity, said A cavity being located adjacent and opening to the diaphragm;

a B wafer bounded on one side by an inner surface and bounded on the opposite side by an outer surface, said inner surface bonded to the B surface of the diaphragm layer, said B wafer containing a B cavity, said B cavity being and located in the bonded structure adjacent and opening to the diaphragm, and on the opposite side thereof from said A cavity;

and wherein an A access passage connects the A cavity to an outer surface of either wafer A or wafer B and a B access passageway connects the B cavity to the outer surface of either wafer A or wafer B, and wherein each access passageway is sufficiently large to allow for communication of a relevant fluid there through;

and wherein said diaphragm layer contains a second diaphragm and wherein said A wafer further contains a second A cavity adjacent and opening to said second diaphragm.

2. A diaphragm transducer as set forth in claim 1 wherein said second A cavity is in communicating connection with a relevant fluid via said A access passageway.

3. A diaphragm transducer as set forth in claim 2 wherein said A access passageway provides access to a relevant fluid located on the outside of said A wafer and wherein said B access passageway provides access to a separate relevant fluid on the outside of said B wafer.

4. A diaphragm transducer as set forth in claim 3 wherein said A and B access passageways both provide access to separate relevant fluids on the outside of the same wafer.