Semiconductor light emitting device substrate strips and packaged semiconductor light emitting devices

• US 8,410,491 B2
• Filed: 10/05/2011
• Issued: 04/02/2013
• Est. Priority Date: 08/21/2006
• Status: Active Grant

• Current Assignee: CREE Led Incorporated (Smart Global Holdings Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Loh, Ban P., Madendorp, Nicholas W. Jr.
• Primary Examiner(s): Pham, Hoai V
• Application Number:
  US13/253,657
• Publication Number:
  US 20120025254A1
• Time in Patent Office: 545 Days
• Field of Search: 257/79, 257/81, 257/98, 257/99, 257/E33.001, 257/E33.061
• US Class Current: 257/79
• CPC Class Codes: B29C 2045/14844 Layers protecting the insert from injected material
• CPC Class Codes: B29C 45/14655 connected to or mounted on a carrier, e.g. lead frame
• CPC Class Codes: B29C 45/14836 Preventing damage of inserts during injection, e.g. collapse of hollow inserts, breakage B29C45/14434 takes precedence
• CPC Class Codes: B29C 45/34 having venting means
• CPC Class Codes: B29K 2083/00 Use of polymers having silicon, with or without sulfur, nitrogen, oxygen, or carbon only, in the main chain, as moulding material
• CPC Class Codes: B29K 2995/0018 having particular optical properties, e.g. fluorescent or phosphorescent
• CPC Class Codes: B29L 2011/0016 Lenses
• 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 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• 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 2924/12041 LED
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 33/52 Encapsulations
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

Semiconductor light emitting device packaging methods include fabricating a substrate configured to mount a semiconductor light emitting device thereon. The substrate may include a cavity configured to mount the semiconductor light emitting device therein. The semiconductor light emitting device is mounted on the substrate and electrically connected to a contact portion of the substrate. The substrate is liquid injection molded to form an optical element bonded to the substrate over the semiconductor light emitting device. Liquid injection molding may be preceded by applying a soft resin on the electrically connected semiconductor light emitting device in the cavity. Semiconductor light emitting device substrate strips are also provided.

Claims

1. A packaged semiconductor light emitting device comprising:

a substrate member including a metal base structure having a mounting portion;

a semiconductor light emitting device mounted on the mounting portion; and

an optical element disposed over the semiconductor light emitting device and bonded directly to the metal base structure;

wherein;

the semiconductor light emitting device is mounted on a substantially planar mounting surface of the mounting portion; and

the optical element is directly bonded to a contact surface of the metal base structure that is substantially coplanar with the mounting surface.

2. The packaged semiconductor light emitting device of claim 1 wherein the metal base structure is a lead frame.

3. The packaged semiconductor light emitting device of claim 1 wherein the substrate member includes the metal base structure overmolded with a substrate formed of a plastic material.

4. The packaged semiconductor light emitting device of claim 3 wherein the plastic material is a high temperature plastic material that is a harder material than a material of the optical element and has a lower optical transmissivity than the material of the optical element.

5. The packaged semiconductor light emitting device of claim 4 wherein the high temperature plastic material includes a reflective material additive.

6. The packaged semiconductor light emitting device of claim 4 wherein the high temperature plastic material comprises a polyphthalamide (PPA) and/or a liquid crystal polymer (LCP) and wherein the optical element comprises a thermoset resin.

7. The packaged semiconductor light emitting device of claim 3 wherein:

a receiving cavity is defined in the substrate; and

the semiconductor light emitting device is electrically connected to a lead defined by the metal base structure that extends through the substrate to the receiving cavity.

8. The packaged semiconductor light emitting device of claim 7 wherein the metal base structure is a lead frame.

9. The packaged semiconductor light emitting device of claim 1 wherein the optical element bonded to the substrate member is liquid injection molded to the substrate member over the semiconductor light emitting device.

10. The packaged semiconductor light emitting device of claim 9 wherein the optical element bonded to the substrate member is liquid injection molded directly onto the substrate member over the semiconductor light emitting device.

11. The packaged semiconductor light emitting device of claim 1 wherein the substrate member includes a receiving cavity within which the semiconductor light emitting device is mounted, and including a soft resin on the electrically connected semiconductor light emitting device in the cavity.

12. The packaged semiconductor light emitting device of claim 11 wherein the semiconductor light emitting device is electrically connected to a contact portion of the metal base structure by a bond wire, and the soft resin is disposed between the optical element and the semiconductor light emitting device.

13. The packaged semiconductor light emitting device of claim 12 wherein the optical element comprises a higher durometer material than the soft resin, has a refractive index substantially similar to a refractive index of the soft resin to limit total internal reflection of the semiconductor light emitting device, and has a coefficient of thermal expansion substantially similar to a coefficient of thermal expansion of the soft resin.

14. The substrate strip of claim 11, wherein the soft resin comprises silicone.

15. The packaged semiconductor light emitting device of claim 1 wherein the optical element has a dome-shaped outer surface.

16. A packaged semiconductor light emitting device comprising:

a substrate member including a metal base structure having a mounting portion;

a semiconductor light emitting device mounted on the mounting portion; and

an optical element disposed over the semiconductor light emitting device and bonded directly to the metal base structure;

wherein the substrate member includes the metal base structure overmolded with a substrate formed of a plastic material.

17. The packaged semiconductor light emitting device of claim 16 wherein the plastic material is a high temperature plastic material that is a harder material than a material of the optical element and has a lower optical transmissivity than the material of the optical element.

18. The packaged semiconductor light emitting device of claim 17 wherein the high temperature plastic material includes a reflective material additive.

19. The packaged semiconductor light emitting device of claim 17 wherein the high temperature plastic material comprises a polyphthalamide (PPA) and/or a liquid crystal polymer (LCP) and wherein the optical element comprises a thermoset resin.

20. The packaged semiconductor light emitting device of claim 16 wherein:

a receiving cavity is defined in the substrate; and

the semiconductor light emitting device is electrically connected to a lead defined by the metal base structure that extends through the substrate to the receiving cavity.

21. The packaged semiconductor light emitting device of claim 20 wherein the metal base structure is a lead frame.

22. The packaged semiconductor light emitting device of claim 16 wherein the optical element has a dome-shaped outer surface.

23. A packaged semiconductor light emitting device comprising:

a substrate member including a mounting portion having a substantially planar mounting surface;

a semiconductor light emitting device mounted on the mounting surface; and

an optical element disposed over the semiconductor light emitting device and bonded directly to a contact surface of the substrate member that is substantially coplanar with the mounting surface;

wherein the substrate member includes a metal base structure; and

wherein the substrate member includes the metal base structure overmolded with a substrate formed of a plastic material.

24. The packaged semiconductor light emitting device of claim 23 wherein the optical element has a dome-shaped outer surface.