Lighting module and method the production thereof

• US 20060163601A1
• Filed: 01/15/2004
• Published: 07/27/2006
• Est. Priority Date: 02/28/2003
• Status: Active Grant

• Current Assignee: OSRAM OLED GMBH (Ams-Osram AG)
• Original Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Inventors: Hahn, Berthold, Lugauer, Hans-Jurgen, Harle, Volker
• Granted Patent: US 7,560,741 B2
• Time in Patent Office: Days
• US Class Current: 257/100
• 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 25/0753 the devices being arranged next to each other
• 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 2924/00014 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 2924/16195 Flat cap [not enclosing an internal cavity]
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: H01L 33/56 Materials, e.g. epoxy or silicone resin
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

An illumination module with at least one thin-film light emitting diode chip which is applied on a chip carrier having electrical connecting conductors and has a first and a second electrical connection side and also an epitaxially fabricated semiconductor layer sequence. The semiconductor layer sequence has an n-conducting semiconductor layer, a p-conducting semiconductor layer and an electromagnetic radiation generating region arranged between these two semiconductor layers and is arranged on a carrier. Moreover, it has a reflective layer at a main area facing toward the carrier, which reflective layer reflects at least one part of the electromagnetic radiation generated in the semiconductor layer sequence back into the latter. The semiconductor layer sequence has at least one semiconductor layer with at least one micropatterned, rough area. The coupling-out area of the thin-film light emitting diode chip is essentially defined by a main area remote from the reflective layer and is free of housing material such as potting or encapsulating material.

Claims

1. A light emitting semiconductor component with at least one thin-film light emitting diode chip which is applied on a chip carrier having electrical connecting conductors and has a first and a second electrical connection side and also an epitaxially fabricated semiconductor layer sequence, wherein the semiconductor layer sequence is arranged on a carrier and comprises:

(a) an n-conducting semiconductor layer, a p-conducting semiconductor layer and an electromagnetic radiation generating region arranged between these two semiconductor layers;

(b) a reflective layer at a main area facing toward the carrier, which reflective layer reflects at least one part of the electromagnetic radiation generated in the semiconductor layer sequence back into the latter;

(c) at least one semiconductor layer with at least one micropatterned, rough area; and

(d) a coupling-out area essentially defined by a main area facing away from the reflective layer; and

wherein the coupling-out area of the thin-film light emitting diode chip is free of housing material such as potting or encapsulating material.

2. The light emitting semiconductor component as claimed in claim 1,

wherein

the semiconductor layer sequence contains at least one material from the system In_xAl_yGa_1-x-yN where 0 x 1, 0 y 1 and x+y 1.

3. The light emitting semiconductor component as claimed in claim 1,

wherein

the semiconductor layer sequence generates electromagnetic radiation with a wavelength in the UV range.

4. The light emitting semiconductor component as claimed in claim 1,

wherein

the coupling-out area of the thin-film light emitting diode chip adjoins a region which is filled with a gas and/or provided with a vacuum.

5. The light emitting semiconductor component as claimed in claim 1,

wherein

the carrier on which the semiconductor layer sequence is arranged is a carrier substrate, in particular a semiconductor carrier substrate.

6. The light emitting semiconductor component as claimed in claim 1,

wherein

the carrier on which the semiconductor layer sequence is arranged is the chip carrier.

7. The light emitting semiconductor component as claimed in claim 1,

wherein

the semiconductor component has a housing frame, which is arranged on the chip carrier or on a housing bottom which is different therefrom and has electrical connecting conductors and on which the chip carrier is applied and to the connecting conductors of which it is electrically connected, and which defines with this a housing cavity in which the thin-film light emitting diode chip is arranged.

8. The light emitting semiconductor component as claimed in claim 7,

wherein

the housing cavity is defined by a leadframe around which a housing basic body is formed, the bottom of the housing basic body with the part of the leadframe integrated therein forming the chip carrier or the housing bottom.

9. The light emitting semiconductor component as claimed in claim 8,

wherein

the housing basic body is essentially composed of plastic.

10. The light emitting semiconductor component as claimed in claim 7,

wherein

the chip carrier or the housing bottom is a printed circuit board which has a metal plate which preferably contains copper and which is electrically and thermally conductively connected to the first electrical connection side of the thin-film light emitting diode chip.

11. The light emitting semiconductor component as claimed in claim 7,

wherein

inner walls of the housing cavity are at least partly provided with a layer, preferably with a metallic or oxidic layer, particularly preferably with a layer having TiO₂, Ag, Al or Au, which is reflective for an electromagnetic radiation generated in the semiconductor component.

12. The light emitting semiconductor component as claimed in claim 11,

wherein

the reflective layer is electrically conductive and also electrically connected to the second electrical connection side of the thin-film light emitting diode chip.

13. The light emitting semiconductor component as claimed in claim 7,

wherein

inner walls of the housing cavity are at least partly provided with a diffusor material or with a layer which is diffusely reflective for an electromagnetic radiation generated in the semiconductor component.

14. The light emitting semiconductor component as claimed in claim 7,

wherein

the housing cavity is closed off in gastight and/or watertight fashion.

15. The light emitting semiconductor component as claimed in claim 7,

wherein

the semiconductor component comprises a radiation-transmissive covering plate fitted in such a way that it essentially covers and/or closes the opening of the housing cavity.

16. The light emitting semiconductor component as claimed in claim 15,

wherein

the covering plate is shaped at least in such a way that it comprises an optical device for the beam shaping of an electromagnetic radiation emitted by the semiconductor component, preferably a focussing apparatus.

17. The light emitting semiconductor component as claimed in claim 15,

wherein

the covering plate essentially comprises at least one of the materials glass, quartz glass, ceramic or glass ceramic.

18. The light emitting semiconductor component as claimed in claim 15,

wherein

the covering plate is provided with a diffusor material which is contained in the covering plate and/or is applied on the covering plate.

19. The light emitting semiconductor component as claimed in claim 15,

wherein

at least one main area of the covering plate, preferably the main area of the covering plate that faces the interior of the housing cavity, has a rough structure.

20. The light emitting semiconductor component as claimed in claim 19,

wherein

the rough structure of the main area of the covering plate is irregular.

21. The light emitting semiconductor component as claimed in claim 20,

wherein

the rough structure of the main area of the covering plate comprises a multiplicity of partial areas which are oblique with respect to a main plane of extent of the semiconductor layer sequence and form a multiplicity of different angles with the latter, and which are distributed statistically over the entire main area in particular with regard to said angles.

22. The light emitting semiconductor component as claimed in claim 19,

wherein

the rough structure of the main area of the covering plate has a structure size which is of the order of magnitude of the wavelength of an electromagnetic radiation emitted by the semiconductor component.

23. The light emitting semiconductor component as claimed in claim 1

wherein

a luminescence conversion material is arranged downstream of the thin-film light emitting diode in the emission direction, which material wavelength-converts at least one part of an electromagnetic radiation emitted by the thin-film light emitting diode.

24. The light emitting semiconductor component as claimed in claim 23,

wherein

the luminescence conversion material comprises at least two phosphors that differ with regard to conversion properties and/or particle size.

25. The light emitting semiconductor component as claimed in claim 14,

wherein

a luminescence conversion material is arranged downstream of the thin-film light emitting diode in the emission direction, which material wavelength-converts at least one part of an electromagnetic radiation emitted by the thin-film light emitting diode;

and

at least one part of the luminescence conversion material is admixed with the covering plate.

26. The light emitting semiconductor component as claimed in claim 14,

wherein

a luminescence conversion material is arranged downstream of the thin-film light emitting diode in the emission direction, which material wavelength-converts at least one part of an electromagnetic radiation emitted by the thin-film light emitting diode;

and

at least one part of the luminescence conversion material is applied to at least one of two main areas of the covering plate, preferably to a main area of the covering plate that faces the interior of the housing cavity.

27. The light emitting semiconductor component as claimed in claim 23,

wherein

at least one part of the luminescence conversion material is applied to the coupling-out area of the thin-film light emitting diode chip.

28. The light emitting semiconductor component as claimed in claim 26,

wherein

the luminescence conversion material is applied in the form of a converter layer whose surface comprises a rough structure.

29. The light emitting semiconductor component as claimed in claim 28,

wherein

the rough structure of the converter layer is irregular.

30. The light emitting semiconductor component as claimed in claim 29,

wherein

the rough structure of the converter layer comprises a multiplicity of partial areas which are oblique with respect to a main plane of extent of the semiconductor layer sequence and form a multiplicity of different angles with the latter, and which are distributed statistically over the entire converter layer in particular with regard to said angles.

31. The light emitting semiconductor component as claimed in claim 28,

wherein

the converter layer comprises a multiplicity of crystallites, and the rough structure of the converter layer is essentially defined by the form of the crystallites.

32. The light emitting semiconductor component as claimed in claim 28,

wherein

the rough structure of the converter layer has a structure size which is of the order of magnitude of the wavelength of an electromagnetic radiation emitted by the semiconductor component.

33. The light emitting semiconductor component as claimed in claim 1,

wherein

the semiconductor component comprises at least two, preferably three, types of thin-film light emitting diode chips which emit visible light in each case having a different wavelength, which is mixed and produces light of a specific color locus in the CIE diagram, in particular white light.

34. The light emitting semiconductor component as claimed in claim 33,

wherein

the semiconductor layer sequence of at least one type of the thin-film light emitting diode chips contains at least one material from the system In_xGa_yAl_1-x-yP where 0 x 1, 0 y 1 and x+y 1.

35. The light emitting semiconductor component as claimed in claim 1,

wherein

the thin-film light emitting diode chip has a thickness of between 0 and 100 m inclusive, preferably between 0 and 50 m inclusive, particularly preferably between 0 and 10 m inclusive.

36. The light emitting semiconductor component as claimed in claim 1,

wherein

the semiconductor component comprises, between at least one electrical connection side of the thin-film light emitting diode chip and an electrical connecting conductor of the chip carrier, an electrical connecting line which essentially comprises a layer of electrically conductive, radiation-transmissive material.

37. The light emitting semiconductor component as claimed in claim 36,

wherein

the electrically conductive, radiation-transmissive material comprises at least one transparent electrically conducting oxide (TCO), preferably indium tin oxide (ITO) or zinc oxide (ZnO).

38. A method for producing a light emitting semiconductor component as claimed in claim 36, having the steps of:

(a) providing at least one thin-film light emitting diode chip with a first and a second electrical connection side, and a chip carrier with at least one first and at least one second electrical connecting conductor;

(b) applying the thin-film light emitting diode chip to the chip carrier;

(c) electrically connecting the first electrical connection side to the first electrical connecting conductor;

(d) coating at least all electrically conductive free areas which are not intended to be electrically connected to the second electrical connection side of the thin-film light emitting diode chip, in particular free areas of the first connecting conductor and also side edges of the thin-film light emitting diode chip, with electrically insulating material;

(e) producing an electrical connection between the second electrical connection side of the thin-film light-emitting diode chip and the second connecting conductor by means of coating the whole area of the chip carrier and of the thin-film light emitting diode chip with an electrically conductive, radiation-transmissive material followed by heat treatment.

39. The method as claimed in claim 38,

in which the first electrical connection side can be contact-connected on the rear side of the thin-film light emitting diode chip, and in which steps (b) and (c) take place simultaneously by means of soldering or adhesively bonding the thin-film light emitting diode chip onto the first electrical connecting conductor by the rear side of said chip.

40. The method as claimed in claim 38,

in which, prior to step (e), electrical contact material is applied to an area via which the second electrical connection side can be electrically contact-connected.

41. The method as claimed in claim 40,

in which the electrical contact material is applied as a thin layer, in the form of narrow strips or in the form of a plurality of layers restricted to small partial regions.

42. The method as claimed in claim 38,

in which the coating with the electrically insulating material takes place by said material firstly being applied to the chip carrier and the thin-film light emitting diode chip and subsequently being patterned, preferably by means of lithography, in such a way that the area via which the second electrical connection side can be electrically contact-connected and also the second electrical connecting conductor are at least partly uncovered for electrical connection.

43. The method as claimed in claim 38,

in which the coating with the electrically insulating material takes place by means of screen printing.

44. The method as claimed in claim 38,

in which the electrically insulating material at least substantially comprises soldering resist.

45. The method as claimed in claim 38,

in which the electrically insulating material comprises SiO₂.

46. The method as claimed in claim 38,

in which a multiplicity of light emitting semiconductor components are produced essentially simultaneously, and in which

the chip carrier comprises a plurality of device sections each containing at least one first and at least one second electrical connecting conductor, and

the semiconductors are subsequently singulated.

47. The method as claimed in claim 46,

in which the device sections are arranged in rowlike fashion in at least one row.

48. The method as claimed in claim 47,

in which individual rows are separated from one another by slots in the chip carrier.