Single package design for 3-axis magnetic sensor

• US 20050122101A1
• Filed: 12/22/2004
• Published: 06/09/2005
• Est. Priority Date: 12/04/2003
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Bohlinger, Michael J., Wan, Hong
• Granted Patent: US 7,271,586 B2
• Time in Patent Office: Days
• US Class Current: 324/252
• CPC Class Codes: G01C 17/28 Electromagnetic compasses with north seeking magnetic elements and having electric pick-offs G01C17/26
• CPC Class Codes: G01R 33/0206 Three-component magnetometers
• CPC Class Codes: G01R 33/025 Compensating stray fields G01R33/0017 takes precedence
• CPC Class Codes: H05K 1/183 Components mounted in and supported by recessed areas of the printed circuit board
• CPC Class Codes: H05K 2201/10151 Sensor
• CPC Class Codes: H05K 3/3436 having an array of bottom contacts, e.g. pad grid array or ball grid array components

Abstract

A sensor package is provided comprising an X-axis sensor circuit component, a Y-axis sensor circuit component, and a Z-axis sensor circuit component, each mounted to a top surface of a rigid substrate. To minimize the height of the package, a channel is cut out of the top surface of the substrate in order to accommodate the Z-axis sensor component. On the Z-axis sensor component, input/output (I/O) pads are all arranged in an array along one edge of the sensor to conductively cooperate with I/O pads, or solder-filled vias, on the substrate located at a top edge of the channel. Once the sensors have all been mounted to the substrate, the package is encapsulated, and the overall height is less than 1.2 mm.

Claims

1. A sensor package comprising:

a rigid substrate, the rigid substrate having a top surface, the top surface including a channel;

an X-axis sensor located on the top surface of the rigid substrate for sensing magnetic field along an X-axis, the X-axis sensor including input/output pads;

a Y-axis sensor located on the top surface of the rigid substrate for sensing magnetic field along a Y-axis, the Y-axis sensor including input/output pads;

a Z-axis sensor located in the channel in the top surface of the rigid substrate for sensing magnetic field along a Z-axis, the Z-axis sensor including input/output pads; and

corresponding input/output pads located on the top surface of the rigid substrate for conductively connecting to respective input/output pads on each sensor.

2. The sensor package of claim 1 further including an encapsulation layer around the package, the height of the package including the encapsulation layer being less than 1.2 mm.

3. The sensor package of claim 1 wherein the input/output pads on the Z-axis sensor are arranged in a vertical array along one edge of the sensor and conductively connect with the corresponding input/output pads on the rigid substrate.

4. The sensor package of claim 3, wherein the input/output pads on the Z-axis sensor are conductively connected to the rigid substrate by solder bumps.

5. The sensor package of claim 4 wherein the input/output pads on the rigid substrate comprise solder filled vias located at a top edge of the channel.

6. The sensor package of claim 1 wherein the channel has a width, and the width corresponds to a thickness of the Z-axis sensor.

7. The sensor package of claim 1 wherein the input/output pads on the rigid substrate are arranged on an outer perimeter in a leadless chip carrier design.

8. The sensor package of claim 1 wherein the input/output pads on the rigid substrate are arranged in a grid in the center of the top surface of the substrate in a ball grid array design.

9. The sensor package of claim 1 wherein the rigid substrate is a printed circuit board.

10. A sensor package comprising:

a rigid substrate, the rigid substrate having a top surface, the top surface including a channel having a width and a depth;

an X/Y-axis sensor located on the top surface of the rigid substrate for sensing magnetic field along an X-axis and Y-axis, the X/Y-axis sensor including input/output pads;

a Z-axis sensor located in the channel in the top surface of the rigid substrate for sensing magnetic field along a Z-axis, the Z-axis sensor including input/output pads;

corresponding input/output pads located on the top surface of the rigid substrate for conductively connecting to respective input/output pads on each sensor; and

an encapsulation layer around the package, the height of the package including the encapsulation layer being less than 1.2 mm.

11. The sensor package of claim 10 wherein the input/output pads on the Z-axis sensor are arranged in a vertical array along one edge of the sensor and conductively connect with the corresponding input/output pads on the rigid substrate.

12. The sensor package of claim 11, wherein the input/output pads on the Z-axis sensor are conductively connected to the rigid substrate by solder bumps.

13. The sensor package of claim 12 wherein the input/output pads on the rigid substrate comprise solder filled vias located at a top edge of the channel.

14. The sensor package of claim 10 wherein the width of the channel corresponds to a thickness of the Z-axis sensor.

15. The sensor package of claim 10 wherein the input/output pads on the rigid substrate are arranged on an outer perimeter in a leadless chip carrier design.

16. The sensor package of claim 10 wherein the input/output pads on the rigid substrate are arranged in a grid in the center of the top surface of the substrate in a ball grid array design.

17. The sensor package of claim 10 wherein the rigid substrate is a printed circuit board.

18. A sensor package comprising:

a rigid substrate, the rigid substrate having a top surface, the top surface including a channel having a width and a depth;

an X-axis sensor located on the top surface of the rigid substrate for sensing magnetic field along an X-axis, the X-axis sensor including input/output pads;

a Y-axis sensor located on the top surface of the rigid substrate for sensing magnetic field along a Y-axis, the Y-axis sensor including input/output pads;

a Z-axis sensor located in the channel in the top surface of the rigid substrate for sensing magnetic field along a Z-axis, the Z-axis sensor including input/output pads;

corresponding input/output pads located on the top surface of the rigid substrate for conductively connecting to respective input/output pads on each sensor; and

an encapsulation layer around the package, the height of the package including the encapsulation layer being less than 1.2 mm; and

wherein the input/output pads on the Z-axis sensor are arranged in a vertical array along one edge of the sensor and conductively communicate with the corresponding input/output pads on the rigid substrate.

19. The sensor package of claim 18, wherein the input/output pads on the Z-axis sensor are conductively connected to the rigid substrate by solder bumps.

20. The sensor package of claim 19 wherein the input/output pads on the rigid substrate comprise solder filled vias located at a top edge of the channel.

21. The sensor package of claim 18 wherein the width of the channel corresponds to a thickness of the Z-axis sensor.

22. The sensor package of claim 18 wherein the rigid substrate is a printed circuit board.

23. A method for manufacturing a sensor package by mounting a Z-axis sensor onto a rigid substrate, the rigid substrate having X- and Y-axis sensors mounted onto a top surface of the substrate, the method comprising:

cutting a channel out of the top surface of the rigid substrate;

forming vias on a top edge of the channel;

filling the vias with solder;

forming input/output pads along only one edge of the Z-axis sensor;

placing bumps of solder on the input/output pads;

inserting the Z-axis sensor into the channel with the bumped input/output pads resting on the top surface of the substrate and contacting the solder-filled vias; and

encapsulating the package.

24. The method of claim 23 wherein the step of cutting further comprises creating the channel with a width corresponding to the thickness of the Z-axis sensor, and a depth of a dimension so that the Z-axis sensor positioned in the channel will not extend past a top surface of the X- and the Y-axis sensors.

25. The method of claim 23 further comprising using a re-flow process for conductively connecting the Z-axis sensor and the rigid substrate.

26. The method of claim 23 wherein the total height of the package is less than 1.2 mm.