Monolithic flow sensor and pressure sensor

• US 6,150,681 A
• Filed: 07/24/1998
• Issued: 11/21/2000
• Est. Priority Date: 07/24/1998
• Status: Expired due to Term

• Current Assignee: Silicon Microstructures, Inc (TE Connectivity Ltd. (United Kingdom))
• Original Assignee: Silicon Microstructures, Inc (TE Connectivity Ltd. (United Kingdom))
• Inventors: Allen, Henry V.
• Primary Examiner(s): MINTEL, WILLIAM A
• Application Number:
  US09/129,198
• Time in Patent Office: 851 Days
• Field of Search: 257/254, 257/417, 257/418, 257/419, 73/204.26, 73/204.24, 73/861.47, 73/718, 73/721, 73/724, 73/727, 73/279, 73/274, 438/53
• US Class Current: 257/254
• CPC Class Codes: G01F 1/28 by drag-force, e.g. vane type or impact flowmeter
• CPC Class Codes: G01F 1/383 with electrical or electro-mechanical indication
• CPC Class Codes: G01L 19/0038 being part of the housing other details about the housing G01L19/14
• CPC Class Codes: G01L 19/0092 Pressure sensor associated with other sensors, e.g. for measuring acceleration or temperature G01L9/025, G01L9/045, G01L9/065, G01L9/085, G01L9/105, G01L9/125, G01L19/02, G01L19/04 take precedence; measuring two or more variable G01D21/02; temperature sensors with pressure compensation G01K1/26
• CPC Class Codes: G01L 19/148 Details about the circuit board integration, e.g. integrated with the diaphragm surface or encapsulation
• CPC Class Codes: G01L 9/0055 bonded on a diaphragm
• CPC Class Codes: G01L 9/065 with temperature compensating means non electric temperature compensating means G01L19/04

Abstract

A monolithic, integrated circuit sensor combining both a differential pressure sensor and a flow sensor on the same silicon chip. The integrated circuit has a diaphragm with a number of piezo-resistive elements placed on it in the normal manner for a pressure sensor. In addition, a channel is provided between the spaces on the two sides of the diaphragm. The channel has a cross-section which is a fraction of the size of the diaphragm. In one embodiment, the channel is a hole in the diaphragm. In another embodiment, the channel is an etched groove in the frame supporting the diaphragm.

Claims

1. An integrated circuit sensor comprising:

a diaphragm having first and second sides in contact with first and second spaces, respectively;

a sensing element on said diaphragm; and

a channel extending from said first space to a position providing gas flow to said second space, said channel having a cross-section which is a fraction of an area of said diaphragm.

2. The integrated circuit of claim 1 wherein said channel comprises a hole in said diaphragm.

3. The integrated circuit of claim 1 further comprising:

a frame supporting said diaphragm; and

wherein said channel comprises a groove etched in said frame.

4. The integrated circuit of claim 3 wherein said groove is V-shaped.

5. The integrated circuit of claim 1 wherein said integrated circuit is formed from <

100>

silicon.

6. The integrated circuit of claim 1 further comprising a temperature compensation circuit of the type designed for pressure sensors, coupled to said sensing element, for compensation for flow measurements.

7. The integrated circuit of claim 1 wherein said sensing element is a plurality of piezoresistive elements.

8. The integrated circuit of claim 1 wherein said sensing element is a capacitive element.

9. An integrated circuit sensor comprising:

a diaphragm having first and second sides in contact with first and second spaces, respectively;

a plurality of piezoresistive elements on said diaphragm;

a channel extending from said first space to a position providing gas flow to said second space, said channel having a cross-section which is a fraction of an area of said diaphragm;

a frame supporting said diaphragm; and

a temperature compensation circuit, coupled to said piezoresistive elements, for compensation for flow measurements;

wherein said channel comprises a V-shaped groove etched in said frame; and

wherein said integrated circuit is formed from <

100>

silicon.

10. The integrated circuit sensor of claim 9 wherein said diaphragm has multiple edges and said V-shaped groove extends along most of at least two of said edges of said diaphragm.