Injection-molded package for MEMS inertial sensor

• US 20060134825A1
• Filed: 12/20/2004
• Published: 06/22/2006
• Est. Priority Date: 12/20/2004
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: DCamp, Jon B., Curtis, Harlan L.
• Granted Patent: US 7,482,193 B2
• Time in Patent Office: Days
• US Class Current: 438/106
• CPC Class Codes: B81B 7/0038 using materials for controlling the level of pressure, contaminants or moisture inside of the package, e.g. getters
• CPC Class Codes: B81C 2203/0154 Moulding a cap over the MEMS device
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• 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 2924/16235 Connecting to a semiconductor or solid-state bodies, i.e. cap-to-chip

Abstract

Methods of packaging devices such as MEMS devices are disclosed. An illustrative method of packaging a device in accordance with an illustrative embodiment of the present invention can include the steps of providing a substrate having an device provided therein or thereon, attaching a cap to the substrate and sealing the device within an interior cavity of the capped substrate, inserting the capped substrate into a vacuum chamber and evacuating gasses and/or contaminants contained within the interior cavity, and then injection molding a package about the capped substrate in the vacuum chamber. A number of small-sized openings disposed through the cap can be utilized to create a controlled vacuum pressure within the interior cavity of the device when the device is in the vacuum chamber, prior to injection molding the package about the capped substrate. In some embodiments, an inert gas can be injected into the evacuated interior cavity to create a partial pressure for the inertial sensor, prior to injection molding the package about the capped substrate.

Claims

1. A method of packaging a MEMS device, comprising the steps of:

providing a substrate having an inertial sensor provided therein or thereon;

attaching a cap to the substrate and sealing the inertial sensor within an interior cavity at least partially formed by the cap and substrate;

inserting the capped substrate into a vacuum chamber and evacuating gasses and/or contaminants contained within the interior cavity to form a reduced pressure or vacuum-filled reference cavity therein; and

injection molding a package about the capped substrate while under a reduced or vacuum pressure within said vacuum chamber.

2. The method of claim 1, further including the step of forming a number of openings through the cap.

3. The method of claim 2, wherein said step of inserting the capped substrate into a vacuum chamber and evacuating gasses and/or contaminants contained therein includes the step of applying a negative vacuum pressure to the capped substrate and drawing the gasses and/or contaminants out of the interior cavity through the openings.

4. The method of claim 1, further including the step of depositing getter material onto the cap prior to said step of attaching the cap to the substrate.

5. The method of claim 4, further including the step of firing the getter after said step of inserting the capped substrate into the vacuum chamber and evacuating gasses and/or contaminants contained within the interior cavity.

6. The method of claim 1, further including the steps of:

providing a lead frame including one or more conductive leads; and

attaching the capped substrate to the lead frame and electrically connecting the inertial sensor to the one or more conductive leads.

7. The method of claim 6, wherein said step of attaching the capped substrate to the lead frame is performed prior to said step of inserting the capped substrate into the vacuum chamber and evacuating gasses and/or contaminants contained within the interior cavity.

8. The method of claim 6, wherein said step of attaching the capped substrate to the lead frame is accomplished using a number of wire bonds.

9. The method of claim 6, wherein said step of attaching the capped substrate to the lead frame is accomplished using a thermocompression bonding technique.

10. The method of claim 1, further including the step of injecting an inert gas into the interior cavity and forming a partial pressure therein.

11. The method of claim 10, wherein said step of injecting an inert gas into the interior cavity and forming a partial pressure therein is performed after said step of evacuating gasses and/or contaminants contained within the interior cavity.

12. The method of claim 1, wherein said step of injection molding a package about the capped substrate is accomplished using a metal injection molding process.

13. The method of claim 1, wherein said step of injection molding a package about the capped substrate is accomplished using a ceramic injection molding process.

14. The method of claim 1, wherein said step of injection molding a package about the capped substrate is accomplished using a plastic injection molding process.

15. The method of claim 1, wherein said inertial sensor is a MEMS gyroscope.

16. The method of claim 1, wherein said inertial sensor is a MEMS accelerometer.

17. A method of packaging a device, comprising the steps of:

providing a substrate having an device provided therein or thereon;

providing a cap having a number openings;

attaching the cap to the substrate and sealing the device within an interior cavity at least partially formed by the cap and substrate;

inserting the capped substrate into a vacuum chamber and drawing gasses and/or contaminants contained within the interior cavity out through the openings to form a controlled vacuum pressure within the interior cavity; and

injection molding a package about the capped substrate.

18. The method of claim 17, further including the step of depositing getter material onto the cap prior to said step of attaching the cap to the substrate.

19. The method of claim 18, further including the step of firing the getter after said step of inserting the capped substrate into the vacuum chamber and evacuating gasses and/or contaminants contained within the interior cavity.

20. The method of claim 17, further including the steps of:

providing a lead frame including one or more conductive leads; and

attaching the capped substrate to the lead frame and electrically connecting the device to the one or more conductive leads.

21. The method of claim 20, wherein said step of attaching the capped substrate to the lead frame is performed prior to said step of inserting the capped substrate into the vacuum chamber and evacuating gasses and/or contaminants contained within the interior cavity.

22. The method of claim 20, wherein said step of attaching the capped substrate to the lead frame is accomplished using a number of wire bonds.

23. The method of claim 20, wherein said step of attaching the capped substrate to the lead frame is accomplished using a thermocompression bonding technique.

24. The method of claim 17, further including the step of injecting an inert gas into the interior cavity and forming a partial pressure therein.

25. The method of claim 24, wherein said step of injecting an inert gas into the interior cavity and forming a partial pressure therein is performed after said step of drawing gasses and/or contaminants contained within the interior cavity out through the openings.

26. The method of claim 17, wherein said step of injection molding a package about the capped substrate is accomplished using a metal injection molding process.

27. The method of claim 17, wherein said step of injection molding a package about the capped substrate is accomplished using a ceramic injection molding process.

28. The method of claim 17, wherein said step of injection molding a package about the capped substrate is accomplished using a plastic injection molding process.

29. The method of claim 17, wherein said device is an inertial sensor.

30. The method of claim 17, wherein said inertial sensor is a MEMS accelerometer or a MEMS gyroscope.

31. A method of packaging a device, comprising the steps of:

providing a substrate having an device provided therein or thereon;

attaching a cap to the substrate and sealing the device within an interior cavity at least partially formed by the cap and substrate;

providing a lead frame including one or more conductive leads;

attaching the capped substrate to the lead frame and electrically connecting the device to the one or more conductive leads of the lead frame;

inserting the capped substrate and lead frame into a vacuum chamber and evacuating gasses and/or contaminants contained within the interior cavity to form a reduced pressure or vacuum-filled reference cavity therein; and

injection molding a package about the capped substrate and at least a portion of the lead frame while under a reduced or vacuum pressure within said vacuum chamber.

32. A method of packaging a device, comprising the steps of:

providing a substrate having an device provided therein or thereon;

providing a cap having a number openings therethrough;

attaching the cap to the substrate and sealing the inertial sensor within an interior cavity that is at least partially formed by cap and substrate;

inserting the capped substrate into a vacuum chamber and drawing gasses and/or contaminants contained within the interior cavity out through the openings to form a controlled vacuum pressure therein;

injecting an inert gas into the interior cavity through the openings to form a partial pressure therein; and

injection molding a package about the capped substrate.

33. A method of packaging a device, comprising the steps of:

providing a substrate having a device provided therein or thereon;

attaching a cap to the substrate and sealing the device within an interior cavity at least partially formed by the capped substrate;

inserting the capped substrate into a vacuum chamber and evacuating gasses and/or contaminants contained within the interior cavity to form a reduced pressure or vacuum-filled reference cavity therein; and

injection molding a metal or ceramic package about the capped substrate while under a reduced or vacuum pressure within said vacuum chamber.

34. A method of packaging a MEMS device, comprising the steps of:

providing a substrate having an inertial sensor provided therein or thereon;

attaching a cap to the substrate and sealing the inertial sensor within an interior cavity at least partially formed by the cap and substrate;

inserting the capped substrate into a vacuum chamber and evacuating gasses and/or contaminants contained within the interior cavity to form a reduced pressure or vacuum-filled reference cavity therein; and

injection molding a package about the capped substrate while under a reduced or vacuum pressure within the vacuum chamber.

35-46. -46. (canceled)