Radiation emitting semiconductor device

• US 7,195,942 B2
• Filed: 05/03/2004
• Issued: 03/27/2007
• Est. Priority Date: 02/15/2000
• Status: Expired due to Term

• Current Assignee: OSRAM GmbH (Ams-Osram AG)
• Original Assignee: OSRAM GmbH (Ams-Osram AG)
• Inventors: Strauss, Uwe, Eisert, Dominik, Zehnder, Ulrich, Mundbrod-Vangerow, Manfred, Haerle, Volker, Kuehn, Frank
• Primary Examiner(s): Lebentritt; Michael
• Assistant Examiner(s): Stevenson; Andre'
• Application Number:
  US10/837,828
• Publication Number:
  US 20050003565A1
• Time in Patent Office: 1,058 Days
• Field of Search: 438/113, 438/33, 438/68, 438/69, 438/42, 438/271, 438/444, 438/458, 438/460, 438/462, 438/464, 349/158, 349/187
• US Class Current: 438/33
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/32257 the layer connector connecting to a bonding area disposed in a recess of the surface of the item
• 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 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 2924/10155 being other than a cuboid
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

Radiation-emitting semiconductor device, method for fabricating same and radiation-emitting optical device.

A radiation-emitting semiconductor device with a multilayer structure (100) comprising a radiation-emitting active layer (10), with electrical contacts (30, 40) for impressing a current in the multilayer structure (100) and with a radiotransparent window layer (20). The window layer is arranged exclusively on the side of the multilayer structure (100) facing away from a main direction of radiation of the semiconductor device and has at least one side wall that includes a first side wall portion (20a) which extends obliquely, concavely or in a stepwise manner toward a central axis of the semiconductor device lying perpendicular to the multilayer sequence. In its subsequent extension toward the back side, viewed from the multilayer structure, the side wall changes over into a second side wall portion (20b) that extends perpendicularly to the multilayer structure, that is, parallel to the central axis, and the portion of the window layer (20) encompassing the second side wall portion (20b) forms a mounting pedestal for the semiconductor device. The first and second side wall portions are fabricated especially preferably by means of a saw blade having a shaped edge. In a preferred optical device, the semiconductor device is mounted window layer downward in a reflector cup.

Claims

1. A method for fabricating a plurality of radiation-emitting semiconductor devices, each said device including a multilayer structure that contains a radiation-emitting active layer and a radiotransparent window layer that is disposed on a side of said multilayer structure facing away from a main direction of radiation of the semiconductor device, said window layer including a first side wall portion which extends obliquely, concavely or in a stepwise manner with respect to a central axis of the semiconductor device lying perpendicular to the multilayer sequence, and which in its subsequent extension toward the back side, viewed from said multilayer structure, changes over into a second side wall portion that forms a mounting pedestal for said semiconductor device, said method comprising the following steps:

fabricating a plurality of mutually adjacent multilayer structures on a large area substrate wafer including a radiotransparent window layer,

sawing into said substrate wafer from the back of the substrate, with a saw blade having a shaped edge that has the negative shape of the intended oblique, concave or stepwise shape of said first side wall portions, to a predetermined depth at which the blade-shaped portion of said saw blade saws into said substrate, said saw blade also having a blade side surface having a negative shape of said second sidewall portion,

dividing said wafer along said sawcuts into separated devices, and

processing the separated devices further.

2. The method as recited in claim 1, wherein the dividing is done by means of a breaking method or a second sawcut.

3. The method as recited in claim 1 or 2, wherein before the back of said substrate is sawn into, metal contacts are produced on the unoccupied surfaces of said substrate or said multilayer structure.

4. The method of claim 1, wherein the sawing is performed with a saw blade having a V-shaped edge.

5. The method of claim 4 wherein a surface of said V-shaped edge forms with said central axis an angle that is between 20°

and 30°

.

6. The method of claim 1 wherein said second sidewall portion and said blade side surface extends parallel to said central axis.

7. The method of claim 1 wherein said substrate wafer is an epitaxial substrate, and said fabricating includes growing said multilayer structure on said epitaxial substrate.

8. The method of claim 1 wherein said further processing includes mounting a said separated device with a reflector cup that has a floor and oblique or paraboloid side walls such that said window layer is oriented toward the floor of said reflector cup.

9. A method for fabricating a plurality of radiation-emitting semiconductor devices, each said device including a multilayer structure that contains a radiation-emitting active layer and a radiotransparent window layer that is disposed on a side of said multilayer structure facing away from a main direction of radiation of the semiconductor device, said window layer including a first side wall portion which extends outwardly with respect to a central axis of the semiconductor device lying perpendicular to the multilayer sequence, and which in its subsequent extension toward the back side, viewed from said multilayer structure, changes over into a second side wall portion that forms a mounting pedestal for said semiconductor device, said method comprising the following steps:

fabricating a plurality of mutually adjacent multilayer structures on a large area substrate wafer including a radiotransparent window layer,

sawing into said substrate wafer from the back of the substrate, with a saw blade having a shaped edge that has the negative shape of the intended outwardly extending shape of said first side wall portions, to a predetermined depth at which the blade-shaped portion of said saw blade saws into said substrate, said saw blade also having a blade side surface having a negative shape of said second sidewall portion,

dividing said wafer along said sawcuts into separated devices, and

processing the separated devices further.

10. The method as recited in claim 9, wherein the dividing is done by means of a breaking method or a second sawcut.

11. The method as recited in claim 9, wherein before the back of said substrate is sawn into, metal contacts are produced on the unoccupied surfaces of said substrate or said multilayer structure.

12. The method of claim 9, wherein the sawing is performed with a saw blade having a V-shaped edge.

13. The method of claim 9 wherein a surface of said V-shaped edge forms with said central axis an angle that is between 20°

and 30°

.

14. The method of claim 9 wherein said second sidewall portion and said blade side surface extends parallel to said central axis.

15. The method of claim 9 wherein said substrate wafer is an epitaxial substrate, and said fabricating includes growing said multilayer structure on said epitaxial substrate.

16. The method of claim 9 wherein said further processing includes mounting said separated device with a reflector cup that has a floor and oblique or paraboloid side walls such that said window layer is oriented toward the floor of said reflector cup.

17. The method of claim 9, wherein the first side wall portion extends away from the central axis obliquely.

18. The method of claim 9, wherein the first side wall portion extends away from the central axis concavely.

19. The method of claim 9, wherein the first side wall portion extends away from the central axis in a stepwise manner.

20. A method for making radiation-emitting semiconductor devices, the method comprising:

fabricating multilayer structures on a front side of a substrate, each multilayer structure comprising at least one radiation-emitting active layer;

inserting a shaped blade into a back side of the substrate to produce a shaped side wall in the substrate, wherein the shaped side wall corresponds to the shape of the blade and comprises a first portion and a second portion, with the first portion extending away from a central axis perpendicular to one of the multilayer structures relative to the second portion;

separating the substrate into different pieces along the shaped side wall, with each piece including a multilayer structure; and

processing each piece further, to produce the radiation-emitting semiconductor devices.

21. The method of claim 20, wherein the first portion of the shaped side wall extends away from the central axis obliquely, concavely, or in a stepwise manner.

22. The method of claim 21, wherein the first portion of the shaped side wall extends away from the central axis obliquely.

23. The method of claim 21, wherein the first portion of the shaped side wall extends away from the central axis concavely.

24. The method of claim 21, wherein the first portion of the shaped side wall extends away from the central axis in a stepwise manner.

25. The method of claim 20, wherein the second portion of the side wall forms part of a mounting pedestal for one of the separated pieces during the further processing.

26. The method of claim 20, wherein the insertion of the shaped blade into the back side of the substrate comprises sawing into the back side of the substrate with the shaped blade.

27. The method of claim 20, wherein the substrate comprises a window adjacent the multilayer structure, wherein the window is transparent to radiation emitted by the active layers.

28. The method of claim 20, wherein the separating comprises breaking or sawing.

29. The method of claim 20, further comprising forming metal contacts on any of the multilayer structures and unoccupied surfaces of the front side of the substrate before the insertion of the shaped blade into the back side of the substrate.

30. The method of claim 20, wherein the shaped blade comprises a V-shaped edge.

31. The method of claim 30, wherein a surface of the V-shaped edge forms with said central axis an angle that is between 20°

and 30°

.

32. The method of claim 20, wherein the second portion of the shaped side wall extends parallel to said central axis.

33. The method of claim 20, wherein the substrate is an epitaxial substrate, and the fabricating comprises growing the multilayer structures on the epitaxial substrate.

34. The method of claim 20, wherein the further processing comprises mounting the separated pieces within a reflector cup that has a floor and oblique or paraboloid side walls such that the back side of the substrate is oriented toward the floor of the reflector cup.