PRESSURE-SENSING INTEGRATED CIRCUIT DEVICE WITH DIAPHRAGM

• US 20170292884A1
• Filed: 11/20/2016
• Published: 10/12/2017
• Est. Priority Date: 04/11/2016
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Inventors: CHING, JR., MARIANO LAYSON, DESCARTIN, ALLEN M., ARAYATA, ALEXANDER M.
• Granted Patent: US 10,151,658 B2
• Time in Patent Office: Days
• CPC Class Codes: G01L 17/00 Devices or apparatus for measuring tyre pressure or the pressure in other inflated bodies
• CPC Class Codes: G01L 19/0038 being part of the housing other details about the housing G01L19/14
• CPC Class Codes: G01L 19/0654 against moisture or humidity
• 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: H01L 21/565 Moulds
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48106 the connector being orthogonal to a side surface of the semiconductor or solid-state body, e.g. parallel layout
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 23/3107 the device being completely enclosed
• CPC Class Codes: H01L 23/49503 characterised by the die pad
• CPC Class Codes: H01L 23/49541 Geometry of the lead-frame
• CPC Class Codes: H01L 24/49 of a plurality of wire connectors
• CPC Class Codes: H01L 24/85 using a wire connector wire bonding in general B23K20/004
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: H01L 2924/146 Mixed devices

Abstract

An integrated circuit (IC) device includes a pressure sensor die, a flexible gel covering a least a pressure-sensing region of the die, and a flexible diaphragm covering the gel. The IC device has encapsulant and a lid that define a cavity above the diaphragm. The lid has an aperture that enables proximate ambient air pressure outside the device to be sensed by the pressure-sensing region through the flexible diaphragm and the flexible gel. The diaphragm protects the gel material from potentially harmful ambient materials. The diaphragm may be a part of the lid.

Claims

1. A pressure-sensing integrated circuit (IC) device, comprising:

a pressure-sensing die;

a flexible gel covering at least a pressure-sensing region of the pressure-sensing die; and

a flexible diaphragm covering the flexible gel, wherein the flexible diaphragm and the flexible gel enable the pressure sensor to sense ambient pressure outside of the IC device.

2. The IC device of claim 1, further comprising:

a lid having an aperture; and

a multi-tiered encapsulant upon which the lid is attached, wherein a recess is defined beneath the lid, wherein;

the die is partially covered by the encapsulant;

the gel is located within a first tier of the encapsulant;

the diaphragm is located within a second tier of the encapsulant above the first tier; and

the lid is located within a third tier of the encapsulant above the second tier.

3. The device of claim 2, wherein the diaphragm comprises:

a convex central section covering the gel;

an annular wall section contacting the encapsulant; and

an annular support section connecting the central section to the wall section.

4. The device of claim 3, wherein:

the central section is made of a first material; and

the wall and support sections are made of a second material different from the first material.

5. The device of claim 3, wherein:

a top surface of the first tier of the encapsulant forms an annular flange around a portion of the gel; and

the support section of the diaphragm covers the flange.

6. The device of claim 2, wherein:

the device further comprises a lead frame having a paddle and a plurality of leads;

the die is attached to the paddle and electrically connected to the leads; and

the encapsulant covers the leads and at least a portion of the die.

7. The device of claim 6, wherein:

the die has a plurality of die pads electrically connected to corresponding leads via corresponding bond wires;

the die pads and the bond wires are covered with the encapsulant; and

the pressure-sensing region is not covered by the encapsulant.

8. The device of claim 1, wherein the diaphragm is integral with the lid.

15. The device of claim 1, wherein the diaphragm is impermeable to at least one gas in the ambient air.

16. The device of claim 1, wherein the diaphragm is a unitary article of manufacture made of one material.

9. An integrated circuit device, comprising:

a lead frame including a die paddle and a plurality of leads surrounding the die paddle;

a pressure-sensing die attached to the die paddle and electrically connected to the leads;

an encapsulant that covers the leads and the electrical connections between the leads and the pressure-sensing die, wherein a bottom surface of the lead frame forms a bottom surface of the integrated circuit device and the encapsulant forms side walls of the device, wherein a cavity is formed between the side walls and over the pressure-sensing die;

a gel material covering a pressure-sensing region on a top surface of the pressure-sensing die;

a lid that extends between the side walls and over the cavity, wherein the lid has a central opening that allows ambient air to enter the cavity so that the pressure-sensing die can measure the ambient air pressure; and

a diaphragm located beneath the central opening and that covers the gel material.

10. The integrated circuit device of claim 9, wherein the diaphragm and the lid are a single unit.

11. The integrated circuit device of claim 10, wherein the lid has a top portion formed of metal and a diaphragm portion formed of a flexible material.

12. A method for assembling an integrated circuit (IC) device, the method comprising:

attaching a die to a paddle of a lead frame, wherein the die comprises a pressure sensor;

electrically connecting the die to leads of the lead frame;

encapsulating a portion of the die and the lead frame with an encapsulant, wherein a recess is formed over the pressure sensor such that at least a pressure-sensing region of the die is not covered by the encapsulant;

placing a gel into the recess and in contact with the pressure-sensing region of the die;

inserting a diaphragm into the recess and in contact with the gel; and

placing a lid having an aperture over the recess and the diaphragm.

13. The method of claim 12, wherein in the encapsulation step comprises:

placing a film-covered shaping form over the pressure sensor to prevent the encapsulant from covering the pressure-sensing region and to form the shape of the recess;

injecting an uncured encapsulant into a molding enclosure containing the die and the lead frame;

curing the encapsulant; and

removing the film-covered shaping form.

14. The method of claim 12, wherein the encapsulation step is performed using film-assisted molding.