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

• US 8,039,848 B2
• Filed: 07/13/2010
• Issued: 10/18/2011
• 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: Medendorp, Nicholas W. Jr., Loh, Ban P.
• Primary Examiner(s): Pham; Hoai V
• Application Number:
  US12/835,013
• Publication Number:
  US 20100276708A1
• Time in Patent Office: 462 Days
• Field of Search: 257/79, 257/81, 257/98, 257/99, 257/E33.001, 257/E33.061
• US Class Current: 257/81
• 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 semiconductor light emitting device substrate strip, comprising:

a metal base structure;

a plurality of high temperature plastic material substrates on the metal base structure, the substrates including semiconductor light emitting device receiving cavities; and

a passageway extending between the receiving cavities configured to direct a flow of resin between the respective receiving cavities.

2. The substrate strip of claim 1, wherein the high temperature plastic material includes a reflective material additive.

3. The substrate strip of claim 2, wherein the high temperature plastic material comprises a polyphthalamide (PPA) and/or a liquid crystal polymer (LCP) and wherein the reflective material additive comprises titanium dioxide (TiO₂) and/or barium sulfate (BaSO₄).

4. The substrate strip of claim 1, further comprising:

a semiconductor light emitting device positioned in each of the receiving cavities; and

a lens material covering each of the receiving cavities and including a residual resin portion extending through the passageway.

5. The substrate strip of claim 4, wherein the semiconductor light emitting devices are electrically connected to leads defined by the metal base structure that extend through the substrates to the receiving cavities.

6. The substrate strip of claim 5, wherein the light emitting devices are electrically connected by bond wires and wherein the substrate strip further comprises a soft resin between the semiconductor light emitting devices and the bond wires and the lens material.

7. The substrate strip of claim 6, wherein the soft resin comprises silicone.

8. The substrate strip of claim 6, wherein the lens material 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.

9. The substrate strip of claim 4, wherein the high temperature plastic material comprises a higher durometer material than the lens material and has a lower optical transmissivity than the lens material.

10. The substrate strip of claim 9, wherein the high temperature plastic material comprises a polyphthalamide (PPA) and/or a liquid crystal polymer (LCP) and wherein the lens material comprises a thermoset resin.

11. The substrate strip of claim 4, wherein the plurality of high temperature plastic material substrates are overmolded on the metal base structure.

12. The substrate strip of claim 1 wherein the metal base structure is a lead frame.