PACKAGED SEMICONDUCTOR LIGHT EMITTING DEVICES HAVING MULTIPLE OPTICAL ELEMENTS AND METHODS OF FORMING THE SAME

• US 20110101385A1
• Filed: 01/04/2011
• Published: 05/05/2011
• Est. Priority Date: 02/12/2007
• Status: Active Grant

• Current Assignee: CREE Led Incorporated (Smart Global Holdings Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Medendorp, Nicholas W. JR.
• Granted Patent: US 8,669,573 B2
• Time in Patent Office: Days
• US Class Current: 257/88
• CPC Class Codes: B29C 33/0022 Multi-cavity moulds B29C33/301 takes precedence
• CPC Class Codes: B29C 33/02 with incorporated heating or cooling means
• CPC Class Codes: B29C 43/021 characterised by the shape of the surface
• CPC Class Codes: B29C 43/18 incorporating preformed parts or layers, e.g. compression moulding around inserts or for coating articles B29C43/206 takes precedence
• CPC Class Codes: B29L 2011/0016 Lenses
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• 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 2924/01068 Erbium [Er]
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H01L 33/52 Encapsulations

Abstract

Methods of packaging a semiconductor light emitting device include providing a substrate having the semiconductor light emitting device on a front face thereof. A first optical element is formed from a first material on the front face proximate the semiconductor light emitting device but not covering the semiconductor light emitting device and a second optical element is formed from a second material, different from the first material, over the semiconductor light emitting device and the first optical element. Packaged semiconductor light emitting devices are also provided.

Claims

1. A method of packaging a semiconductor light emitting device, comprising:

providing a substrate having the semiconductor light emitting device on a front face thereof;

forming a first optical element from a first material on the front face proximate the semiconductor light emitting device but not covering the semiconductor light emitting device; and

forming a second optical element from a second material, different from the first material, over the semiconductor light emitting device and the first optical element.

2. The method of claim 1, wherein at least one of forming the first optical element or forming the second optical element comprises compression molding the respective optical element.

3. The method of claim 1, wherein the first optical element and the second optical element have different refractive indexes selected to provide a desired optical characteristic for the packaged semiconductor light emitting device.

4. The method of claim 3, wherein the first and second optical elements are configured to provide a selected viewing angle to the packaged semiconductor light emitting device.

5. The method of claim 1, wherein the first material has an adhesion characteristic selected to facilitate adhesion of the first optical element to the substrate during compression molding and/or to limit stress applied to the light emitting device and/or a wire bond coupled thereto during thermal cycling of the packaged semiconductor light emitting device.

6. The method of claim 1, wherein providing the substrate includes mounting the semiconductor light emitting device flush on the front face thereof without a reflector cavity and wherein the second optical element is molded to and extends from the front face of the substrate in a region surrounding the semiconductor light emitting device and extends over the semiconductor light emitting device.

7. The method of claim 1, wherein forming the first optical element comprises forming the first optical element using a process other than compression molding.

8. The method of claim 1, wherein the substrate includes a plurality of semiconductor light emitting devices on the front face thereof and wherein forming the first optical element and forming the second optical element comprise forming a plurality of first optical elements and forming a plurality of second optical elements on the front face of the substrate over corresponding ones of the semiconductor light emitting devices.

9. A method of packaging a semiconductor light emitting device, comprising:

providing a substrate having the semiconductor light emitting device on a front face thereof;

forming a first optical element from a first material on the front face proximate the semiconductor light emitting device; and

forming a second optical element from a second material, different from the first material, over the semiconductor light emitting device and the first optical element, wherein forming the first optical element comprises forming the first optical element using a process other than compression molding and wherein forming the second optical element comprises compression molding the respective optical element on the front face.

10. The method of claim 9, wherein the process other than compression molding comprises dispensing and/or bonding.

11. The method of claim 9, wherein the first optical element and the second optical element have different refractive indexes selected to provide a desired optical characteristic for the packaged semiconductor light emitting device.

12. A method of packaging a semiconductor light emitting device, comprising:

providing a substrate having the semiconductor light emitting device on a front face thereof;

forming a first optical element from a first material on the front face proximate the semiconductor light emitting device; and

forming a second optical element from a second material, different from the first material, over the semiconductor light emitting device and the first optical element without leaving a gap between the first optical element and the second optical element, wherein the first optical element and the second optical element have different refractive indexes selected to provide a desired optical characteristic for the packaged semiconductor light emitting device.

13. The method of claim 12, wherein at least one of forming the first optical element or forming the second optical element comprises compression molding the respective optical element and

14. A packaged semiconductor light emitting device, comprising:

a substrate;

a semiconductor light emitting device on a front face of the substrate;

a first optical element on the front face of the substrate proximate the semiconductor light emitting device but not covering the semiconductor light emitting device; and

a second optical element on the front face of the substrate over the semiconductor light emitting device and the first optical element.

15. The device of claim 14, wherein the semiconductor light emitting device is flush on the front face of the substrate without a reflector cavity and wherein the second optical element extends from the front face of the substrate in a region surrounding the semiconductor light emitting device and extends over the semiconductor light emitting device.

16. The device of claim 14, wherein the semiconductor light emitting device comprises a plurality of semiconductor light emitting devices and wherein the compression molded optical elements comprise a plurality of optical elements over corresponding ones of the semiconductor light emitting devices.

17. The device of claim 14, further comprising a wire bond that electrically couples the semiconductor light emitting device to a contact portion of the substrate and wherein at least one of the optical elements is a compression molded optical element that directly contacts the wire bond.

18. The device of claim 17, wherein the first optical element comprises a first material having an adhesion characteristic selected to facilitate adhesion of the first optical element to the substrate during compression molding and/or to limit stress applied to the light emitting device and/or a wire bond coupled thereto during thermal cycling of the packaged semiconductor light emitting device.

19. A packaged semiconductor light emitting device, comprising:

a substrate;

a semiconductor light emitting device on a front face of the substrate;

a first optical element on the front face of the substrate proximate the semiconductor light emitting device, wherein the first optical element comprises a first material; and

a second optical element on the front face of the substrate over the semiconductor light emitting device and the first optical element with no gap between the first optical element and the second optical element, wherein the second optical element comprises a second material, different from the first material, and wherein the first optical element and the second optical element have different refractive indexes selected to provide a desired optical characteristic for the packaged semiconductor light emitting device.

20. The device of claim 19, wherein the first optical element is on the front face of the substrate proximate the semiconductor light emitting device but not covering the semiconductor light emitting device and wherein the second optical element is on the front face of the substrate over the semiconductor light emitting device and the first optical element