HIGH OUTPUT POWER LIGHT EMITTING DEVICE AND PACKAGED USED THEREFOR

• US 20090261374A1
• Filed: 03/07/2008
• Published: 10/22/2009
• Est. Priority Date: 03/12/2007
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Hayashi, Masaki
• Granted Patent: US 8,610,143 B2
• Time in Patent Office: Days
• US Class Current: 257/99
• CPC Class Codes: H01L 2224/05554 being square
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• 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 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 24/73 Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• 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 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/01066 Dysprosium [Dy]
• CPC Class Codes: H01L 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/12035 Zener diode
• CPC Class Codes: H01L 2924/12036 PN diode
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/20753 : larger or equal to 30 microns less than 40 microns
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding
• CPC Class Codes: H01L 33/60 : Reflective elements
• CPC Class Codes: H01L 33/62 : Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H01L 33/647 : the elements conducting electric current to or from the semiconductor body

Abstract

An object of the present invention is to provide a light emitting device that has high output power and long service life where a package is suppressed from discoloring due to heat generation. The light emitting device 1 of the present invention contains a light emitting element 10, a package 40 formed of a thermosetting resin, the package having a recess 43 wherein the light emitting element 10 is mounted, a first lead electrode 20 which is exposed at the bottom of the recess 43 of the package 40 and whereon the light emitting element 10 is mounted, and a second lead electrode 30 which is exposed at the bottom of the recess 43 of the package 40 and is electrically connected to the light emitting element 10. The light emitting element 10 is bonded to the first lead electrode 20 through a eutectic layer 70, and at least a surface of the first electrode 20 is coated with an Ag film 22, a thickness of the Ag film 22 being in the range from 0.5 μm to 20 μm.

Claims

1-8. -8. (canceled)

9. A light emitting device comprising:

a light emitting element;

a package formed of a thermosetting resin, the package having a recess wherein the light emitting element is mounted;

a first lead electrode which is exposed at the bottom of the recess of the package and whereon the light emitting element is mounted; and

a second lead electrode which is exposed at the bottom of the recess of the package and is electrically connected to the light emitting element;

wherein the light emitting element is bonded to the first lead electrode through a eutectic layer, and

at least a surface of the first electrode is coated with an Ag film, a thickness of the Ag film being in the range from 0.5 μ

m to 20 μ

m.

10. The light emitting device according to claim 9, wherein the thickness of the Ag film is in the range from 1 μ

m to 15 μ

m.

12. The light emitting device according to claim 9, wherein the eutectic layer is formed of a soldering material having a melting point in the range of 200°

C. to 350°

C.

14. The light emitting device according to claim 9, wherein the package is formed of a cured thermosetting epoxy resin compound containing a triazine-induced epoxy resin.

16. The light emitting device according to claim 9, wherein the package has a reflectivity of 70% or higher for light of 430 nm or longer, and

the light emitting element emits a light having a peak emission wavelength in the range from 430 nm to 530 nm.

18. The light emitting device according to claim 9, further comprising a transparent sealing member for sealing the light emitting element, the sealing material being formed of a thermosetting resin.

11. A light emitting device comprising:

a light emitting element;

a package formed of a thermosetting resin, the package having a recess wherein the light emitting element is mounted;

a first lead electrode which is exposed at the bottom of the recess of the package and whereon the light emitting element is mounted; and

a second lead electrode which is exposed at the bottom of the recess of the package and is electrically connected to the light emitting element;

wherein the light emitting element is bonded to the first lead electrode through a eutectic layer,

at least a surface of the first electrode is coated with an Ag film, and

a part of the surface of the first or second lead electrode is a bonding region to be bonded with the light emitting element, the bonding region having a flatness in the range from 0.001 to 50 μ

m.

13. The light emitting device according to claim 11, wherein the eutectic layer is formed of a soldering material having a melting point in the range of 200°

C. to 350°

C.

15. The light emitting device according to claim 11, wherein the package is formed of a cured thermosetting epoxy resin compound containing a triazine-induced epoxy resin.

17. The light emitting device according to claim 11, wherein the package has a reflectivity of 70% or higher for light of 430 nm or longer, and

the light emitting element emits a light having a peak emission wavelength in the range from 430 μ

m to 530 μ

m.

19. The light emitting device according to claim 11, further comprising a transparent sealing member for sealing the light emitting element, the sealing material being formed of a thermosetting resin.

20. A method for manufacturing a light emitting device comprising:

a light emitting element;

a package formed of a thermosetting resin, the package having a recess wherein the light emitting element is mounted;

a first lead electrode which is exposed at the bottom of the recess of the package and whereon the light emitting element is mounted;

a second lead electrode which is exposed at the bottom of the recess of the package and is electrically connected to the light emitting element;

an Ag film for coating at least a surface of the first electrode; and

a eutectic layer positioned between the light emitting element and the first lead electrode;

the method comprising the steps of;

coating the surface of the first electrode with the Ag film;

sandwiching both the first and second lead electrodes between a upper die and a lower die, at least the upper die having an inner cavity corresponding to a shape of the package, and pressing the first and second lead electrodes against a protrusion provided with the upper die for forming the recess of the package;

injecting a thermosetting resin into the inner cavities of the upper die and the lower die and heat curing the thermosetting resin to form the package;

applying the eutectic layer formed of a metal soldering material to a back surface of the light emitting element;

mounting the light emitting element in the recess of the package so that the eutectic layer makes contact with an upper surface of the first lead electrode, and fixing the light emitting element on the first lead electrode by heating and melting the eutectic layer; and

electrically connecting the light emitting element to the first and second lead electrodes.