Electronic microcircuit having internal light enhancement

• US 20060118807A1
• Filed: 12/01/2005
• Published: 06/08/2006
• Est. Priority Date: 12/08/2004
• Status: Active Grant

• Current Assignee: Keysight Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Carlson, Brian, Ives, Fred H., Nicholson, Dean, Storie, Jonathan
• Granted Patent: US 7,847,301 B2
• Time in Patent Office: Days
• US Class Current: 257/99
• 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 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• 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 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/19107 off-chip wires
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding

Abstract

By adding light reflective and/or transparent and/or translucent material within a micro-electronic circuit housing, improved light transfer is achieved between a light generation source and a light utilization device. In one embodiment, the reflective material is placed on the inside surface of a non-metallic housing lid and the light from the light source (typically an LED) reflects from the reflective material and impacts the device (typically an FET). In another embodiment, the LED and FET are encased in a clear (low light-loss) material (typically silicone overcoat) so as to allow the light from the LED to reflect from the top of the clear material onto the FET. If desired, an opaque encapsulant surrounds the clear material and fills out the volume within the housing. In another embodiment, clear or translucent (as opposed to opaque) encapsulant can be used to serve dual purpose as both the structural (volume filling, defined package share/outline) agent as well as to permit the internal light transmission and reflections to illuminate the device.

Claims

1. A non-metallic package comprising therein:

an LED;

an electronic device; and

a clear seal to allow light from said LED to be reflected onto said electronic device.

2. The package of claim 1 wherein said electronic device is selected from the list of GaAs device, InP, and GaN devices.

3. The package of claim 2 wherein said package is selected from the list of ceramic and plastic.

4. The package of claim 3 wherein said plastic is a QFN package.

5. The package of claim 3 comprising:

a non-metallic lid; and

a bonding agent on the edges of said package lid where said edges contact said package so as to create a hermetic seal for said electronic package, said bonding agent selected from the list of metallic, glass, and epoxy.

6. The package of claim 5 wherein said lid contains reflective material.

7. The package of claim 3 further comprising:

a lid shaped to focus light onto specific electronic devices.

8. The package of claim 5 wherein said clear seal is applied to an inside surface of said lid to enhance reflectivity as well as hermeticity.

9. The package of claim 1 wherein said clear seal surrounds said LED and said electronic device.

10. The package of claim 9 wherein said seal is a clear silicone polymer.

11. The package of claim 9 wherein said clear seal has a low loss to light in a particular frequency range.

12. The package of claim 1 wherein said clear seal comprises:

a lens positioned so as to focus light from said LED onto said electronic device.

13. The package of claim 1 wherein said clear seal comprises:

a molding material that serves both as a structural body of the package and a light transmission/reflection medium.

14. The method of making a micro-circuit, said method comprising:

mounting at least one electronic component on a substrate; and

coating said mounted electrical component with a low light loss material so as to promote light transmission among coplanarly mounted electrical components.

15. The method of claim 14 wherein said low light loss material provides rigidity to said mounted components.

16. The method of claim 14 further comprising:

applying a rigid opaque encapsulant over said low light loss material.

17. The method of claim 14 wherein said mounting comprises surface mounting.

18. The method of claim 14 further comprising:

encasing said coated electrical components within a non-metallic housing.

19. The method of claim 14 further comprising:

encapsulating said coated mounted electrical components to form a particular shape having a particular volume.

20. The method of claim 19 wherein said particular shape and volume is such as to allow said encapsulated electronic components to fit within a QFN.

21. The method of claim 14 wherein said substrate is within a framework having sides and an open top, said method further comprising:

positioning a lid over said framework sides; and

sealing said lid to said framework.

22. The method of claim 21 wherein said sealing comprises:

sealing the surfaces of said framework and said lid to prevent moisture from passing through said lid.

23. The method of claim 21 wherein said sealing comprises using non-metallic molded and epoxy sealed packages to provide mechanical robustness.

24. The method of claim 22 wherein said sealing further operates to reflect light from one electronic component mounted on said substrate to another electronic component mounted on said substrate.

33. The circuit of claim 23 wherein said reflecting means comprises:

a non-metallic lid; and

a reflective seal placed either on the inside or the outside surface of said lid.

25. An electronic micro-circuit having internal light enhancement, said micro-circuit enclosed within a non-metallic package, said package comprising:

a substrate upon which a plurality of components can be mounted;

a source of light mounted on said substrate;

an electronic device mounted coplanarly with said source of light, the operation of said electronic component being enhanced by light from said light source; and

means for reflecting light emitted from said light source such that at least a portion of said light impacts said electronic device.

26. The circuit of claim 25 wherein said electronic device is selected from the list of GaAs, InP, and GaN devices.

27. The circuit of claim 25 wherein said electronic device is a FET or an IC.

28. The circuit of claim 25 wherein said light source is an LED chip.

29. The circuit of claim 25 wherein said reflecting means comprises:

a reflective seal placed on at least one surface of said package.

30. The circuit of claim 25 wherein said reflecting means comprises:

a clear silicone overcoat surrounding said light source and said electronic circuit.

31. The circuit of claim 25 wherein said reflecting means comprises:

a rigid clear encapsulant surrounding said electronic device and said light source.

32. The circuit of claim 25 wherein said reflecting means comprises:

a non-metallic lid that is naturally light reflective;

or

a reflective seal placed on the inside surface of said lid.

34. The circuit of claim 25 wherein said reflecting means comprises:

a lens positioned so as to focus light from said light source onto said electronic device.

35. An attenuator comprising:

a plurality of attenuation stages serially interconnected;

each said stage having at least one switching device requiring enhancement by light impacting said switching device;

each said stage being contained in a separate non-metallic housing, each said housing containing at least one said switching device and at least one light source, said switching device and said light source mounted coplanar to each other; and

a light reflector within each said package for directing light from said light source to impact said switching device.

36. The attenuator of claim 35 wherein said switching device and said light source are mounted on a common substrate.

37. The attenuator of claim 36 wherein said light reflector comprises a coating positioned on a non-metallic lid of said package.

38. The attenuator of claim 36 wherein said reflector comprises a low light loss material encompassing said switching device and said light source.

39. The attenuator of claim 36 wherein said switching device comprises a GaAs FET and said light source comprises an LED chip, said LED positioned so that light emits there from in a direction away from said switching device.