Methods for packaging image sensitive electronic devices

• US 20030232461A1
• Filed: 02/21/2003
• Published: 12/18/2003
• Est. Priority Date: 06/04/2002
• Status: Active Grant

• Current Assignee: SuperMax Technology Ltd.
• Original Assignee: Chad A. Cobbley, Todd O. Bolken
• Inventors: Cobbley, Chad A., Bolken, Todd O.
• Granted Patent: US 7,195,940 B2
• Time in Patent Office: Days
• US Class Current: 438/106
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/32145 the bodies being stacked
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48145 the bodies being stacked
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/484 Connecting portions
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/85399 Material
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 2224/92 Specific sequence of method steps
• CPC Class Codes: H01L 2224/92247 the second connecting process involving a wire connector
• CPC Class Codes: H01L 2225/06506 Wire or wire-like electrical connections between devices
• CPC Class Codes: H01L 2225/06555 Geometry of the stack, e.g. form of the devices, geometry to facilitate stacking
• CPC Class Codes: H01L 23/293 Organic, e.g. plastic
• CPC Class Codes: H01L 23/3128 the substrate having spherical bumps for external connection
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/73 Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• CPC Class Codes: H01L 25/0657 : Stacked arrangements of devices
• CPC Class Codes: H01L 27/14603 : Special geometry or disposition of pixel-elements, address-lines or gate-electrodes
• CPC Class Codes: H01L 27/14618 : Containers
• CPC Class Codes: H01L 27/14625 : Optical elements or arrangements associated with the device
• CPC Class Codes: H01L 27/14683 : Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof not peculiar thereto H01L21/00
• 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 2924/00011 : Not relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/15174 : in different layers of the multilayer substrate
• CPC Class Codes: H01L 2924/15311 : being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/16152 : Cap comprising a cavity for hosting the device, e.g. U-shaped cap
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/1815 : Shape
• CPC Class Codes: H01L 31/0203 : Containers; Encapsulations , e.g. encapsulation of photodiodesfor photovoltaic devices H01L31/048; for organic photosensitive devices H10K30/80
• CPC Class Codes: Y10S 257/924 : with passive device, e.g. capacitor, or battery, as integral part of housing or housing element, e.g. cap

Abstract

The invention provides methods for packaging for electronic devices that are light or other radiation-sensitive, such as image sensors including CCD or CMOS chips. In one embodiment of the invention, an image sensor package is assembled by surrounding a chip with a barrier of transfer mold compound and covering the chip with a transparent lid. In another embodiment of the invention, the perimeter area of a chip, including interconnections such as wire bonds and bond pads, is encapsulated with a liquid dispensed epoxy, and a transparent lid is attached. In yet another embodiment of the invention, chip encapsulation is accomplished with a unitary shell of entirely transparent material. In yet another embodiment of the invention, a substrate-mounted chip and a transparent lid are loaded into a transfer mold that holds them in optimal alignment. The transfer mold is then filled with molding compound to encapsulate the chip and interconnections, and to retain the transparent lid.

Claims

1. A method for assembling a package containing an electronic device sensitive to light or other radiation comprising:

mounting said electronic device on a carrier substrate having at least one conductive trace thereon, said at least one conductive trace having a first end and a second end;

providing at least one electrical interconnection between said electronic device and said first end of said at least one conductive trace;

forming a molded barrier on said carrier substrate, said molded barrier surrounding a central exposed area that contains said electronic device and said at least one electrical interconnection;

positioning a transparent lid over said central exposed area; and

fixing said transparent lid in place.

2. The method according to claim 1, wherein said forming a molded barrier is performed prior to said mounting said electronic device.

3. The method according to claim 1, further comprising:

monitoring an output of said electronic device during said positioning said transparent lid, said output varying in relation to said positioning of said transparent lid; and

fixing said transparent lid in place when positioned such that said output has a desired value.

4. The method according to claim 1, wherein said positioning said transparent lid comprises supporting said transparent lid on a ledge formed on an inner perimeter of said molded barrier.

5. The method according to claim 1, wherein said positioning said transparent lid comprises filling said central exposed area of said molded barrier with a clear compound to form a transparent shell that encapsulates said electronic device and said at least one electrical interconnection.

6. The method according to claim 5, further comprising:

forming a surface of said transparent shell into the shape of a lens.

7. The method according to claim 1, wherein said fixing said transparent lid in place comprises applying an activated adhesive between an outer perimeter of said transparent lid and an inner perimeter of said molded barrier and setting said activated adhesive.

8. The method according to claim 1, wherein said mounting said electronic device comprises providing an image sensor.

9. The method according to claim 1, further comprising selecting said electronic device to comprise a solid-state device comprising at least one of a charge coupled device, a complementary metal-oxide semiconductor and an erasable programmable read-only memory.

10. The method according to claim 9, further comprising fabricating said electronic device to comprise a plurality of semiconductor devices.

11. The method according to claim 1, further comprising forming said carrier substrate of a material comprising at least one of plastic, FR-4 and BT.

12. The method according to claim 11, further comprising:

positioning at least one intermediate conductive trace in communication with said second end of said at least one conductive trace of said carrier substrate.

13. The method according to claim 12, wherein a plurality of said packages each containing at least one of said electronic device is formed onto a single carrier substrate and further comprising:

dividing said carrier substrate into separate pieces, each of said pieces comprising one of said plurality of packages.

14. A method for assembling a package containing an electronic device sensitive to light or other radiation comprising:

mounting said electronic device on a carrier substrate having at least one conductive trace thereon, said at least one conductive trace having a first end and a second end;

providing at least one electrical interconnection between a bond pad on said electronic device and said first end of said at least one conductive trace;

encapsulating said first end of said at least one conductive trace, said at least one electrical interconnection and said bond pad of said electronic device with a nonconductive material dispensed in liquid form;

covering a surface of said electronic device with a transparent lid;

curing the liquid nonconductive material to at least a semisolid state; and

retaining said transparent lid by an adhesive interface with said nonconductive material.

15. The method according to claim 14, further comprising:

placing a gasket on said surface of said electronic device prior to said covering said surface with said transparent lid.

16. The method according to claim 14, further comprising:

molding a layer of material onto said carrier substrate that encapsulates said nonconductive material and an outer perimeter of said transparent lid.

17. The method according to claim 14, wherein said mounting said electronic device comprises providing an image sensor.

18. The method according to claim 14, further comprising selecting said electronic device to comprise a solid-state device comprising at least one of a charge coupled device, a complementary metal-oxide semiconductor and an erasable programmable read-only memory.

19. The method according to claim 18, further comprising fabricating said electronic device to comprise a plurality of semiconductor devices.

20. The method according to claim 14, further comprising forming said carrier substrate of a material comprising at least one of plastic, FR-4 and BT.

21. The method according to claim 20, further comprising:

attaching at least one discrete conductive element to said second end of said at least one conductive trace of said carrier substrate.

22. The method according to claim 21, wherein a plurality of said packages, each containing an electronic device, are formed onto a single carrier substrate and further comprising:

dividing said single carrier substrate into separate pieces, each of said pieces comprising one of said packages.

23. A method for assembling a package containing an electronic device sensitive to light or other radiation comprising:

mounting said electronic device on a carrier substrate having at least one conductive trace thereon, said at least one conductive trace having a first end and a second end;

providing at least one electrical interconnection between a bond pad on said electronic device and said first end of said at least one conductive trace; and

enclosing said first end of said at least one conductive trace, said at least one electrical interconnection and said electronic device within a shell formed entirely of a transparent material.

24. The method according to claim 23, wherein said enclosing said first end of said at least one conductive trace, said at least one electrical interconnection and said electronic device within a shell formed entirely of a transparent material comprises molding a clear compound directly onto said carrier substrate to encapsulate said first end of said at least one conductive trace, said at least one electrical interconnection and said electronic device.

25. The method according to claim 24, further comprising:

forming a surface of said shell into the shape of a lens.

26. The method according to claim 24, further comprising selecting said clear compound to be a material selected from a group consisting of epoxy, polystyrene and silicon.

27. The method according to claim 24, further comprising forming said electronic device to be an image sensor.

28. The method according to claim 24, further comprising selecting said electronic device to comprise a solid-state device selected from a group consisting of a charge coupled device, a complementary metal-oxide semiconductor and an erasable programmable read-only memory.

29. The method according to claim 28, further comprising forming said electronic device as a chip stack.

30. The method according to claim 24, further comprising forming said carrier substrate of a material selected from a group consisting of plastic, FR-4 and BT.

31. The method according to claim 30, further comprising:

attaching at least one discrete conductive element to said second end of said at least one conductive trace of said carrier substrate.

32. The method according to claim 31, wherein a plurality of said packages, each contain an electronic device, are formed onto a single carrier substrate and further comprising:

dividing said single carrier substrate into separate pieces, each of said pieces comprising one of said packages.

33. The method according to claim 23, wherein said enclosing said first end of said at least one conductive trace, said at least one electrical interconnection and said electronic device within a shell formed entirely of a transparent material comprises adhesively attaching a preformed shell onto said carrier substrate.

34. A method for assembling a package containing an electronic device sensitive to light or other radiation comprising:

mounting said electronic device on a carrier substrate having at least one conductive trace thereon, said at least one conductive trace having a first end and a second end;

providing at least one electrical interconnection between said electronic device and said first end of said at least one conductive trace;

loading a transparent lid into a mold tooling element;

loading said carrier substrate with said electronic device and said at least one electrical interconnection into said mold tooling element so that a surface of said electronic device is aligned against said transparent lid;

filling said mold tooling element with molding compound;

forming a molded layer on said carrier substrate to encapsulate said at least one electrical interconnection and a perimeter of said electronic device; and

retaining said transparent lid with said molded layer.

35. The method according to claim 34, further comprising:

applying a layer of conformal film between an inside surface of said mold tooling element and said transparent lid prior to said filling said mold tooling element.

36. The method according to claim 34, further comprising selecting said electronic device to be an image sensor.

37. The method according to claim 34, further comprising selecting said electronic device to comprise a solid-state device selected from a group consisting of a charge coupled device, a complementary metal-oxide semiconductor and an erasable programmable read-only memory.

38. The method according to claim 37, further comprising fabricating said electronic device as a chip stack.

39. The method according to-claim 34, further comprising forming said carrier substrate of a material selected from a group consisting of plastic, FR-4 and BT.

40. The method according to claim 39, further comprising:

attaching at least one discrete conductive element to said second end of said at least one conductive trace of said carrier substrate.

41. The method according to claim 40, wherein a plurality of said packages, each containing an electronic device, are formed onto a single carrier substrate and further comprising:

dividing said single carrier substrate into separate pieces, each of said pieces comprising one of said packages.