PACKAGE-IN-PACKAGE SEMICONDUCTOR SENSOR DEVICE

• US 20160027992A1
• Filed: 07/22/2014
• Published: 01/28/2016
• Est. Priority Date: 07/22/2014
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Lo, Wai Yew
• Granted Patent: US 9,362,479 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01L 19/0069 from the sensor to its support
• CPC Class Codes: G01L 19/0076 using buried connections
• CPC Class Codes: G01L 19/0084 to the outside of the housing other details about the housing see G01L19/14
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45139 Silver (Ag) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/45147 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/4554 Coating
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/85444 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/85447 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/92247 the second connecting process involving a wire connector
• CPC Class Codes: H01L 24/00 Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/15724 : Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2924/15747 : Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2924/1576 : Iron [Fe] as principal constituent
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/207 : Diameter ranges
• CPC Class Codes: H10N 30/02 : Forming enclosures or casings
• CPC Class Codes: H10N 30/03 : Assembling devices that include piezoelectric or electrostrictive parts
• CPC Class Codes: H10N 30/302 : Sensors
• CPC Class Codes: H10N 30/802 : Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits
• CPC Class Codes: H10N 30/883 : Additional insulation means preventing electrical, physical or chemical damage, e.g. protective coatings

Abstract

A semiconductor sensor device includes a device substrate, a micro-controller unit (MCU) die attached to the substrate, and a packaged pressure sensor having a sensor substrate and a pressure sensor die. The sensor substrate has a front side with the pressure sensor die attached to it, a back side, and an opening from the front side to the back side. A molding compound encapsulates the MCU die, the device substrate, and the packaged pressure sensor. A back side of the sensor substrate and the opening in the sensor substrate are exposed on an outer surface of the molding compound.

Claims

1. A method for assembling a semiconductor sensor device, the method comprising:

a) providing a sensor substrate having a front side and a back side;

b) forming an opening through the sensor substrate;

c) flip-chip bonding a pressure sensor die to the front side of the sensor substrate;

d) filling a region between the pressure sensor die and the sensor substrate with a pressure-sensitive gel; and

e) encapsulating the sensor substrate, the pressure sensor die, and the pressure-sensitive gel with a molding compound, leaving the back side of the sensor substrate exposed.

2. The method of claim 1, wherein the pressure sensor die can sense atmospheric pressure outside of the semiconductor sensor device via the opening in the sensor substrate and the pressure-sensitive gel.

3. The method of claim 1, wherein after step d) and before step e), the method further comprises:

providing a device substrate;

attaching a microcontroller unit (MCU) die to the device substrate;

attaching the pressure sensor die to the MCU die; and

electrically connecting the MCU die to bond pads on the sensor substrate with bond wires;

wherein step e) includes encapsulating the MCU die and the device substrate with the molding compound, and

wherein the sensor substrate provides electrical interconnection between the bond pads and the pressure sensor die.

4. The method of claim 3, wherein the device substrate is a lead frame comprising a die paddle and at least one lead, and the step of attaching the MCU die to the substrate comprises:

attaching the MCU to the die paddle; and

electrically connecting the MCU die to the at least one lead with the bond wires.

5. The method of claim 4, further comprising:

depositing a layer of adhesive onto the die paddle before the MCU is attached to the die paddle.

6. The method of claim 3, further comprising:

depositing a layer of adhesive onto the MCU before the pressure-sensor die is attached to the MCU.

7. The method of claim 3, wherein, after step d) and before step e), further comprising:

attaching another sensor die on the device substrate; and

electrically connecting the another sensor die to the MCU with additional bond wires;

wherein step e) includes encapsulating the another sensor die and the additional bond wires with the molding compound.

8. The method of claim 1, wherein the sensor substrate is formed by the steps of:

forming a first insulating layer;

forming a metal layer on the first insulating layer;

patterning the metal layer to form traces therein;

forming a second insulating layer on the first insulating layer and the traces;

forming a first set of vias in at least the first insulating layer and connected to at least one of the traces, the first set of vias having exposed ends;

forming a second set of vias in the first and second insulating layers and connected to at least one of the traces;

and removing a portion of the second insulating layer and the second set of vias to expose ends of the second set of vias;

wherein the first insulating layer forms the front side of the sensor substrate and the second insulating layer forms the back side of the sensor substrate, wherein the pressure sensor die is flip-chip bonded to the exposed ends of the first set of vias.

9. The method of claim 8, further comprising conductive metal bumps for flip-chip bonding the sensor substrate to the exposed ends of the first set of vias.

10. The method of claim 1, wherein the encapsulation in step e) is performed by:

applying a mold pin to the opening in the sensor substrate to prevent the molding compound from entering the opening; and

injecting the molding compound around the sensor substrate, pressure sensor die, and pressure-sensitive gel after applying the mold pin; and

curing the molding compound.

11. The method of claim 1, wherein the sensor substrate is formed by the steps of:

forming a first insulating layer;

forming a metal layer on the first insulating layer;

patterning the metal layer to form traces therefrom and wire-bond pads connected to the traces;

forming a second insulating layer on the first insulating layer and the traces;

forming vias in at least the first insulating layer and connected to at least one of the traces, the vias having an exposed ends; and

removing a portion of the second insulating layer to expose the wire-bond pads of the traces;

wherein the first insulating layer forms the front side of the sensor substrate and the second insulating layer forms the back side of the sensor substrate, wherein the pressure sensor die is flip-chip bonded to the exposed ends of the vias.

12. A semiconductor sensor device assembled using the method of claim 1.

13. A semiconductor sensor device, comprising:

a device substrate;

a micro controller unit (MCU) die attached to the device substrate;

a pressure sensor package having a sensor substrate and a pressure sensor die electrically connected to the sensor substrate, the sensor substrate having a front side with the pressure sensor die attached thereto, a back side, and an opening from the front side to the back side; and

a molding compound encapsulating the MCU die, the device substrate, and the pressure sensor package, the molding compound having an outer surface;

wherein the back side of the sensor substrate and the opening in the sensor substrate are exposed on the outer surface of the molding compound.

14. The sensor device of claim 13, wherein:

the device substrate is a lead frame comprising a die paddle and at least one lead;

the MCU die is attached to the die paddle by an adhesive layer; and

the MCU die is electrically connected to the at least one lead with at least one bond wire.

15. The sensor device of claim 13, wherein the pressure sensor die is flip-chip mounted to the sensor substrate using conductive bumps, the sensor device further comprising:

a pressure-sensitive gel covering the conductive bumps and the pressure sensor die, and at least partially filling the opening in the sensor substrate.

16. The sensor device of claim 13, wherein the pressure sensor die is attached to the MCU using a layer of adhesive.

17. The sensor device of claim 13, wherein the sensor substrate comprises:

first and second insulating layers;

patterned traces disposed between the first and second insulating layer;

a first set of metal vias disposed in the first insulating layer and connecting to the patterned traces, the first set of metal vias having exposed ends on the front side of the sensor substrate; and

metal bumps on the exposed ends of the first set of metal vias, wherein the metal bumps electrically connect the pressure sensor die to exposed ends of the first set of metal vias on the sensor substrate.

18. The sensor device of claim 17, wherein the sensor substrate further comprises:

a second set of vias disposed in the first and insulating layers and connecting to the patterned traces;

wherein a portion of the second insulating layer is absent, thereby exposing ends of the second set of vias to form substrate bond pads connected to the patterned traces, and

wherein the MCU die is electrically connected to the substrate bond pads on the exposed end portions of the second set of vias.

19. The sensor device of claim 18, wherein a portion of the second insulating layer is absent thereby exposing a portion of the patterned traces and substrate bond pads connected to the patterned traces, and wherein the MCU die is electrically connected to the substrate bond pads on the sensor substrate.

20. The sensor device of claim 13, further comprising:

another sensor die attached to the device substrate and electrically connected to the MCU with additional bond wires.