Submounts for semiconductor light emitting devices and methods of forming packaged light emitting devices including dispensed encapsulants

• US 7,834,375 B2
• Filed: 04/10/2008
• Issued: 11/16/2010
• Est. Priority Date: 08/04/2005
• Status: Active Grant

• Current Assignee: CREE Led Incorporated (Smart Global Holdings Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Andrews, Peter
• Primary Examiner(s): Toledo; Fernando L
• Application Number:
  US12/100,647
• Publication Number:
  US 20080191237A1
• Time in Patent Office: 950 Days
• Field of Search: 438/26, 438/27, 257/100
• US Class Current: 257/100
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32245 the item being metallic
• 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 2224/48247 connecting the wire to a bond pad of the item
• 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 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/10253 Silicon [Si]
• CPC Class Codes: H01L 2933/005 relating to encapsulations
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/52 Encapsulations
• CPC Class Codes: H01L 33/54 having a particular shape

Abstract

A submount for mounting an LED chip includes a substrate, a die attach pad configured to receive an LED chip on an upper surface of the substrate, a first meniscus control feature on the substrate surrounding the die attach pad and defining a first encapsulant region of the upper surface of the substrate, and a second meniscus control feature on the substrate surrounding the first encapsulant region and defining a second encapsulant region of the upper surface of the substrate. The first and second meniscus control features may be substantially coplanar with the die attach pad. A packaged LED includes a submount as described above and further includes an LED chip on the die attach pad, a first encapsulant on the substrate within the first encapsulant region, and a second encapsulant on the substrate within the second encapsulant region and covering the first encapsulant. Method embodiments are also disclosed.

Claims

1. A submount for mounting an LED, the submount comprising:

a substrate having an upper surface;

a die attach pad on the upper surface of the substrate, the die attach pad configured to receive an LED chip;

a first meniscus control feature on the substrate, the first meniscus control feature surrounding the die attach pad and defining a first encapsulant region of the upper surface of the substrate and configured to limit the flow of a liquid encapsulant material across the upper surface of the substrate;

a second meniscus control feature on the substrate, the second meniscus control feature surrounding the first encapsulant region and defining a second encapsulant region of the upper surface of the substrate including an exposed portion of the substrate between the first meniscus control feature and the second meniscus control feature, wherein the second meniscus control feature is configured to limit the flow of liquid encapsulant material across the upper surface of the substrate; and

a third meniscus control feature disposed within the first encapsulant region and surrounding the die attach pad.

2. The submount of claim 1, wherein the third meniscus control feature defines a third encapsulant region within the first encapsulant region and wherein the first meniscus control feature and the third meniscus control feature define a region in the first encapsulant region surrounding the third encapsulant region.

3. The submount of claim 2, wherein the region of the first encapsulant region defined by the first meniscus control feature and the third meniscus control feature is ring-shaped.

4. The submount of claim 1, further comprising a plurality of surface features on the substrate between the first meniscus control feature and the second meniscus control feature, wherein a path extending in a radial direction from the first meniscus control feature to the second meniscus control feature is interrupted by at least one surface feature.

5. The submount of claim 1, further comprising at least one surface feature on the substrate between the first meniscus control feature and the second meniscus control feature.

6. The submount of claim 5, wherein the at least one surface feature and the first and second meniscus control features comprise the same material.

7. The submount of claim 6, wherein the at least one surface feature and the first and second meniscus control features comprise a plated metal film, and/or a polymer.

8. The submount of claim 6, wherein the first and/or second meniscus control feature comprises a patterned feature on the substrate.

9. The submount of claim 8, wherein the patterned feature comprises a patterned metal feature.

10. The submount of claim 6, wherein the first and/or second meniscus control feature comprises a corner of a patterned feature on the substrate.

11. A submount for mounting an LED, the submount comprising:

a substrate having an upper surface;

a die attach pad on the upper surface of the substrate, the die attach pad configured to receive an LED chip;

a first meniscus control feature on the substrate, the first meniscus control feature surrounding the die attach pad and defining a first encapsulant region of the upper surface of the substrate and configured to limit the flow of a liquid encapsulant material;

a second meniscus control feature on the substrate, the second meniscus control feature surrounding the first encapsulant region and defining a second encapsulant region of the upper surface of the substrate and configured to limit the flow of liquid encapsulant material;

a third meniscus control feature disposed within the first encapsulant region and surrounding the die attach pad; and

a plurality of surface features on the substrate between the first meniscus control feature and the second meniscus control feature, wherein a path extending in a radial direction from the first meniscus control feature to the second meniscus control feature is interrupted by at least one surface feature;

wherein the surface features are discontinuous.

12. A submount for mounting an LED, the submount comprising:

a substrate having an upper surface;

a die attach pad on the upper surface of the substrate, the die attach pad configured to receive an LED chip;

a first meniscus control feature on the substrate, the first meniscus control feature surrounding the die attach pad and defining a first encapsulant region of the upper surface of the substrate and configured to limit the flow of a liquid encapsulant material;

a second meniscus control feature on the substrate, the second meniscus control feature surrounding the first encapsulant region and defining a second encapsulant region of the upper surface of the substrate and configured to limit the flow of liquid encapsulant material;

a third meniscus control feature disposed within the first encapsulant region and surrounding the die attach pad; and

at least one surface feature on the substrate between the first meniscus control feature and the second meniscus control feature;

wherein the at least one surface feature and the first and second meniscus control features comprise a metal film.