METHOD OF MAKING LIGHT EMITTING DEVICE HAVING A MOLDED ENCAPSULANT

• US 20070141739A1
• Filed: 10/20/2006
• Published: 06/21/2007
• Est. Priority Date: 10/24/2005
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Thompson, D., Ouderkirk, Andrew, Leatherdale, Catherine, Boardman, Larry, Kecman, Fedja
• Granted Patent: US 7,595,515 B2
• Time in Patent Office: Days
• US Class Current: 438/28
• CPC Class Codes: C08J 2383/04 Polysiloxanes
• CPC Class Codes: C08J 3/243 Two or more independent types of crosslinking for one or more polymers
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• 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 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 2924/01067 Holmium [Ho]
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/1815 Shape
• CPC Class Codes: H01L 2933/0091 Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

Disclosed herein is a method of making a light emitting device comprising an LED and a molded silicon-containing encapsulant. The method includes contacting the LED with a photopolymerizable composition containing a silicon-containing resin having silicon-bonded hydrogen and aliphatic unsaturation and two metal-containing catalysts. One catalyst may be activated by actinic radiation, and the second by heat but not the actinic radiation. Polymerization of the photopolymerizable composition to form the encapsulant may be carried out by selectively activating the different catalysts. At some point before polymerization is complete, a mold is used to impart a predetermined shape to the encapsulant.

Claims

1. A method of making a light emitting device, the method comprising:

providing a light emitting diode;

contacting the light emitting diode with a photopolymerizable composition comprising;

a silicon-containing resin comprising silicon-bonded hydrogen and aliphatic unsaturation,

a first metal-containing catalyst that may be activated by actinic radiation, and

a second metal-containing catalyst that may be activated by heat but not the actinic radiation; and

contacting the photopolymerizable composition with a mold.

2. The method of claim 1, further comprising:

applying actinic radiation to the photopolymerizable composition after contacting it with the mold,

wherein the actinic radiation is at a wavelength of 700 nm or less and initiates hydrosilylation within the silicon-containing resin, the hydrosilylation comprising reaction between the silicon-bonded hydrogen and the aliphatic unsaturation.

3. The method of claim 1, further comprising:

heating the photopolymerizable composition to a temperature of less than about 150°

C. after contacting it with the mold, wherein heating initiates hydrosilylation within the silicon-containing resin, the hydrosilylation comprising reaction between the silicon-bonded hydrogen and the aliphatic unsaturation.

4. The method of claim 1, further comprising:

applying actinic radiation to the photopolymerizable composition after contacting it with the mold, wherein the actinic radiation is at a wavelength of 700 nm or less and initiates hydrosilylation within the silicon-containing resin, thereby forming a partially polymerized composition, the hydrosilylation comprising reaction between the silicon-bonded hydrogen and the aliphatic unsaturation; and

heating the partially polymerized composition to a temperature of less than about 150°

C. to further initiate hydrosilylation.

11. The method as in any one of claims 1, 5 and 8, wherein the mold is transparent to the actinic radiation.

12. The method as in any one of claims 2, 4, 5, 6 and 9, wherein applying actinic radiation comprises activating the light emitting diode.

13. The method of claim 1, the mold comprising a mold material and being shaped to impart a positive or negative lens on a substantial portion of the surface of the photopolymerizable composition.

14. The method of claim 1, the mold comprising a mold material and being shaped to impart macrostructures, each macrostructure having a dimension of from 10 um to 1 mm.

15. The method of claim 1, the mold comprising a mold material and being shaped to impart microstructures, each microstructure having a dimension of from 100 nm to less than 10 um.

5. A method of making a light emitting device, the method comprising:

providing a light emitting diode;

contacting the light emitting diode with a photopolymerizable composition comprising;

a silicon-containing resin comprising silicon-bonded hydrogen and aliphatic unsaturation,

a first metal-containing catalyst that may be activated by actinic radiation, and

a second metal-containing catalyst that may be activated by heat but not the actinic radiation; and

applying actinic radiation to the photopolymerizable composition, wherein the actinic radiation is at a wavelength of 700 nm or less and initiates hydrosilylation within the silicon-containing resin, thereby forming a partially polymerized composition, the hydrosilylation comprising reaction between the silicon-bonded hydrogen and the aliphatic unsaturation; and

contacting the partially polymerized composition with a mold.

6. The method of claim 5, further comprising:

applying actinic radiation to the partially polymerized composition after contacting it with the mold, wherein the actinic radiation applied to the partially polymerized composition is at a wavelength of 700 nm or less and further initiates hydrosilylation within the silicon-containing resin.

7. The method of claim 5, further comprising:

heating the partially polymerized composition to a temperature of less than about 150°

C. after contacting it with the mold, wherein heating further initiates hydrosilylation within the silicon-containing resin.

8. A method of making a light emitting device, the method comprising:

providing a light emitting diode;

contacting the light emitting diode with a photopolymerizable composition comprising;

a silicon-containing resin comprising silicon-bonded hydrogen and aliphatic unsaturation,

a first metal-containing catalyst that may be activated by actinic radiation, and

a second metal-containing catalyst that may be activated by heat but not the actinic radiation; and

heating the photopolymerizable composition to a temperature of less than about 150°

C. to initiate hydrosilylation within the silicon-containing resin, thereby forming a partially polymerized composition, the hydrosilylation comprising reaction between the silicon-bonded hydrogen and the aliphatic unsaturation; and

contacting the partially polymerized composition with a mold.

9. The method of claim 8, further comprising:

applying actinic radiation to the partially polymerized composition, wherein the actinic radiation is at a wavelength of 700 nm or less and further initiates hydrosilylation within the silicon-containing resin.

10. The method of claim 8, further comprising:

heating the partially polymerized composition to a temperature of less than about 150°

C. to further initiate hydrosilylation within the silicon-containing resin.

16. A method of making a light emitting device, the method comprising:

providing a light emitting diode;

contacting the light emitting diode with a photopolymerizable composition comprising;

a silicon-containing resin comprising silicon-bonded hydrogen and aliphatic unsaturation,

a first metal-containing catalyst that may be activated by actinic radiation, and

a second metal-containing catalyst that may be activated by heat but not the actinic radiation;

shaping a surface of the photopolymerizable composition by contacting it with a mold;

applying actinic radiation to the photopolymerizable composition to form an at least partially polymerized composition, wherein the actinic radiation is at a wavelength of 700 nm or less and initiates hydrosilylation within the silicon-containing resin, the hydrosilylation comprising reaction between the silicon-bonded hydrogen and the aliphatic unsaturation;

separating the mold from the at least partially polymerized composition.

17. A light emitting device prepared according to the method of claim 16.

18. A method of making a light emitting device, the method comprising:

providing a light emitting diode;

contacting the light emitting diode with a photopolymerizable composition comprising;

a silicon-containing resin comprising silicon-bonded hydrogen and aliphatic unsaturation,

a first metal-containing catalyst that may be activated by actinic radiation, and

a second metal-containing catalyst that may be activated by heat but not the actinic radiation;

shaping a surface of the photopolymerizable composition by contacting it with a mold;

heating the photopolymerizable composition to a temperature of less than about 150°

C. to form an at least partially polymerized composition, wherein heating initiates hydrosilylation within the silicon-containing resin, the hydrosilylation comprising reaction between the silicon-bonded hydrogen and the aliphatic unsaturation;

separating the mold from the at least partially polymerized composition.

19. A light emitting device prepared according to the method of claim 18.

20. A method of making a light emitting device, the method comprising:

providing a light emitting diode;

contacting the light emitting diode with a photopolymerizable composition comprising;

a silicon-containing resin comprising silicon-bonded hydrogen and aliphatic unsaturation,

a first metal-containing catalyst that may be activated by actinic radiation, and

a second metal-containing catalyst that may be activated by heat but not the actinic radiation;

applying actinic radiation to the photopolymerizable composition to form an at least partially polymerized composition, wherein the actinic radiation is at a wavelength of 700 nm or less and initiates hydrosilylation within the silicon-containing resin, the hydrosilylation comprising reaction between the silicon-bonded hydrogen and the aliphatic unsaturation;

shaping a surface of the at least partially polymerized composition by contacting it with a mold;

further initiating hydrosilylation within the silicon-containing resin of the partially polymerized composition by;

applying actinic radiation is at a wavelength of 700 nm or less, or

heating to a temperature of less than about 150°

C.; and

separating the mold from the polymerized composition.

21. A light emitting device prepared according to the method of claim 20.

22. A method of making a light emitting device, the method comprising:

providing a light emitting diode;

contacting the light emitting diode with a photopolymerizable composition comprising;

a silicon-containing resin comprising silicon-bonded hydrogen and aliphatic unsaturation,

a first metal-containing catalyst that may be activated by actinic radiation, and

a second metal-containing catalyst that may be activated by heat but not the actinic radiation;

heating the photopolymerizable composition to a temperature of less than about 150°

C. to initiate hydrosilylation within the silicon-containing resin, thereby forming a partially polymerized composition, the hydrosilylation comprising reaction between the silicon-bonded hydrogen and the aliphatic unsaturation;

shaping a surface of the at least partially polymerized composition by contacting it with a mold;

further initiating hydrosilylation within the silicon-containing resin of the partially polymerized composition by;

applying actinic radiation is at a wavelength of 700 nm or less, or

heating to a temperature of less than about 150°

C.; and

separating the mold from the polymerized composition.

23. A light emitting device prepared according to the method of claim 22.

24. A light emitting device comprising:

a light emitting diode;

a photopolymerizable composition comprising;

a silicon-containing resin comprising silicon-bonded hydrogen and aliphatic unsaturation, and

a first metal-containing catalyst that may be activated by actinic radiation, and

a second metal-containing catalyst that may be activated by heat but not the actinic radiation; and

a mold.

25. The light emitting device of claim 24, wherein the photopolymerizable composition is at least partially polymerized.

26. A light emitting device comprising:

a light emitting diode;

an at least partially polymerized composition in contact with the light emitting diode and formed from a photopolymerizable composition comprising;

a silicon-containing resin comprising silicon-bonded hydrogen and aliphatic unsaturation,

a first metal-containing catalyst that may be activated by actinic radiation, and

a second metal-containing catalyst that may be activated by heat but not the actinic radiation; and

wherein a surface of the at least partially polymerized composition is shaped as a positive or negative lens on a substantial portion thereof.

27. A light emitting device comprising:

a light emitting diode;

an at least partially polymerized composition in contact with the light emitting diode and formed from a photopolymerizable composition comprising;

a silicon-containing resin comprising silicon-bonded hydrogen and aliphatic unsaturation,

a first metal-containing catalyst that may be activated by actinic radiation, and

a second metal-containing catalyst that may be activated by heat but not the actinic radiation; and

wherein a surface of the at least partially polymerized composition is shaped with macrostructures, each macrostructure having a dimension of from 10 um to 1 mm.

28. A light emitting device comprising:

a light emitting diode;

an at least partially polymerized composition in contact with the light emitting diode and formed from a photopolymerizable composition comprising;

a silicon-containing resin comprising silicon-bonded hydrogen and aliphatic unsaturation,

a first metal-containing catalyst that may be activated by actinic radiation, and

a second metal-containing catalyst that may be activated by heat but not the actinic radiation; and

wherein a surface of the at least partially polymerized composition is shaped with microstructures, each microstructure having a dimension of from 100 nm to less than 10 um.