Flip chip led apparatus

• US 6,483,196 B1
• Filed: 04/03/2000
• Issued: 11/19/2002
• Est. Priority Date: 04/03/2000
• Status: Expired due to Term

• Current Assignee: Current Lighting Solutions, LLC (f/k/a GE Lighting Solutions, LLC) (American Industrial Partners)
• Original Assignee: General Electric Company
• Inventors: Minnear, William P., Wojnarowski, Robert J., Benicewicz, Pamela K.
• Primary Examiner(s): POTTER, ROY KARL
• Application Number:
  US09/542,037
• Time in Patent Office: 960 Days
• Field of Search: 257/778, 257/737, 257/642, 257/432, 257/435
• US Class Current: 257/778
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/0558 being stacked
• CPC Class Codes: H01L 2224/05611 Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/05624 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/05644 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/05655 Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/05669 Platinum [Pt] as principal constituent
• CPC Class Codes: H01L 2224/05671 Chromium [Cr] as principal constituent
• CPC Class Codes: H01L 2224/05684 Tungsten [W] as principal constituent
• CPC Class Codes: H01L 2224/13 of an individual bump connector
• CPC Class Codes: H01L 2224/48091 Arched
• 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 24/05 of an individual bonding area
• 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 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/54 having a particular shape

Abstract

A flip chip structure of a light-emitting device comprising a UV/blue light emitting diode (LED) is disclosed. The flip chip structure is optimized to produce unique light focusing and phosphor illumination out the bottom of the structure. The flip chip structure includes a substrate, a gallium nitride layer epitaxially grown on a top surface of the substrate, and one or more layers of lensing material deposited on a bottom surface of the substrate. The lensing material is preferably a polymer lensing material, an index matching material, or a mixture thereof. The gallium nitride layer is deposited in the form of one or more odd-sided polygons, for enhanced light extraction.

Claims

1. A semiconductor device formed in a flip chip arrangement comprising:

a substrate formed of a substantially transparent material;

a semiconductor layer deposited on a top surface of the substrate; and

one or more layers of lensing material deposited on a bottom surface of the substrate for redirecting of light, the lensing material being a polymer lensing material, an index matching material or a mixture thereof.

2. The semiconductor device of claim 1 wherein the one or more layers of lensing material further comprise a phosphor material.

3. The semiconductor device of claim 1 further comprising a phosphor material deposited on a topmost surface of the one or more layers of lensing material.

4. The semiconductor device of claim 1 wherein the semiconductor layer is gallium nitride.

5. The semiconductor device of claim 1 further comprising one or more reflectors formed on one or more sides of the semiconductor device.

6. The semiconductor device of claim 5 wherein the one or more reflectors redirect light at a ninety degree angle.

7. The semiconductor device of claim 1 wherein the substrate includes one or more laser ablation areas formed on the bottom surface thereof.

8. The semiconductor device of claim 4 wherein the semiconductor layer is deposited in the form of one or more odd-sided polygons.

9. The semiconductor device of claim 1 wherein the polymer lensing material is selected from the group consisting of epoxy, PMMA, polycarbonate, polyimide or mixtures thereof.

10. The semiconductor device of claim 1 wherein the index matching material is a silicone (RTV).

11. The semiconductor device of claim 1 wherein each layer of the one or more layers of lensing material has a lower index of refraction than that of the substrate and the semiconductor layer.

12. The semiconductor device of claim 1 wherein each layer of the one or more layers of lensing material has an index of refraction lower than the layer of lensing material deposited directly underneath.

13. The semiconductor device of claim 1 wherein the lensing material is further deposited on a topmost surface of the semiconductor layer.

14. The semiconductor device of claim 1 further comprising a fresnel lens positioned on the topmost surface of the layer of lensing material.

15. The semiconductor device of claim 1 wherein the substrate is formed of sapphire (Al₂O₃).

16. The semiconductor device of claim 1 wherein the polymer, index matching material or mixture thereof has an optical index lower than that of the semiconductor layer.

17. A light emitting diode (LED) interconnection package comprising:

an LED formed in a flip chip arrangement, the LED comprising a substrate formed of a substantially transparent material, a semiconductor layer deposited on a top surface of the substrate, and one or more layers of a polymer deposited on a bottom surface of the substrate, the LED having a contact surface and bonding pads attached thereto, each bonding pad including a flip chip solder bump;

contact pads connected to the solder bumps;

an interconnect board connected to the contact pads for electrical connection of the LED; and

a lead frame connected to the interconnect board.

18. The LED interconnection package of claim 17 wherein the one or more layers of polymer further comprise a phosphor material.

19. The LED interconnection package of claim 17 further comprising a phosphor material deposited on a topmost surface of the one or more layers of polymer.

20. The LED of claim 17 further comprising one or more reflectors formed on one or more sides of the LED.

21. The LED of claim 20 wherein the one or more reflectors redirect light at a ninety degree angle.

22. The LED of claim 17 wherein the substrate includes one or more laser ablation areas formed on the bottom thereof.

23. The LED of claim 17 wherein the semiconductor layer is deposited in the form of one or more odd-sided polygons.

24. The LED of claim 17 wherein the one or more layers of polymer is an epoxy or mixtures thereof.

25. The LED of claim 17 wherein the one or more layers of polymer are further deposited on a topmost surface of the semiconductor layer.

26. The LED of claim 17 further comprising a fresnel lens positioned on the topmost surface of the one or more layers of polymer.

27. The LED of claim 17 wherein the substrate is formed of sapphire (Al₂O₃).

28. The LED of claim 17 wherein the semiconductor layer is an epitaxially grown gallium nitride layer.

29. The LED of claim 17 wherein the one or more layers of polymer has a lower index of refraction than the substrate and the semiconductor layer.

30. The LED of claim 17 wherein the semiconductor layer is deposited in the form of one or more odd-sided polygons.

31. A semiconductor device formed in a flip chip arrangement comprising:

a substrate formed of a substantially transparent material; and

a semiconductor layer deposited on the top surface of the substrate in the form of one or more odd-sided polygons.

32. The semiconductor device of claim 31 wherein the semiconductor layer is gallium nitride.

33. The semiconductor device of claim 31 further comprising one or more layers of lensing material deposited on the bottom surface of the substrate.

34. The semiconductor device of claim 33 wherein the one or more layers of lensing material have an index of refraction lower than that of the substrate and the semiconductor layer.

35. The semiconductor device of claim 31 wherein the substrate is formed of sapphire (Al₂O₃).

36. The semiconductor device of claim 31 wherein the one or more odd-side polygons are electrically connected.