Method of making radiation emitter devices

• US 6,849,867 B2
• Filed: 01/08/2003
• Issued: 02/01/2005
• Est. Priority Date: 03/15/1999
• Status: Expired due to Term

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Roberts, John K., Reese, Spencer D.
• Primary Examiner(s): Flynn, Nathan J.
• Assistant Examiner(s): Andújar, Leonardo
• Application Number:
  US10/338,540
• Publication Number:
  US 20030168670A1
• Time in Patent Office: 755 Days
• Field of Search: 257 99-100, 257/98, 438 22- 29
• US Class Current: 257/25
• CPC Class Codes: B60Q 1/2665 on rear-view mirrors lighting devices for vehicle interior on or for rear-view mirrors B60Q3/258
• CPC Class Codes: H01L 2224/04042 Bonding areas specifically adapted for wire connectors, e.g. wirebond pads
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/4823 connecting the wire to a pin of the item
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48463 the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
• CPC Class Codes: H01L 2224/48599 Principal constituent of the connecting portion of the wire connector being Gold (Au)
• CPC Class Codes: H01L 2224/48699 Principal constituent of the connecting portion of the wire connector being Aluminium (Al)
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• CPC Class Codes: H01L 2224/85 using a wire connector
• CPC Class Codes: H01L 2224/97 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 23/49562 for devices being provided for in H01L29/00
• CPC Class Codes: H01L 24/05 of an individual bonding area
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/49 of a plurality of wire connectors
• 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 2924/00012 : 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 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/01019 : Potassium [K]
• CPC Class Codes: H01L 2924/0102 : Calcium [Ca]
• CPC Class Codes: H01L 2924/01027 : Cobalt [Co]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01075 : Rhenium [Re]
• CPC Class Codes: H01L 2924/01077 : Iridium [Ir]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/01322 : Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/09701 : Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 2924/10329 : Gallium arsenide [GaAs]
• CPC Class Codes: H01L 2924/10336 : Aluminium gallium arsenide [AlGaAs]
• CPC Class Codes: H01L 2924/12041 : LED
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/12044 : OLED
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/351 : Thermal stress
• 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 33/483 : Containers
• CPC Class Codes: H01L 33/50 : Wavelength conversion elements
• CPC Class Codes: H01L 33/54 : having a particular shape
• CPC Class Codes: H01L 33/56 : Materials, e.g. epoxy or silicone resin
• 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 33/641 : characterized by the materials
• CPC Class Codes: H01L 33/642 : characterized by the shape
• CPC Class Codes: H01L 33/647 : the elements conducting electric current to or from the semiconductor body
• CPC Class Codes: H10K 50/84 : Passivation; Containers; Encapsulations
• CPC Class Codes: H10K 50/85 : Arrangements for extracting light from the devices
• CPC Class Codes: H10K 50/87 : Arrangements for heating or cooling

Abstract

A radiation emitting device of the present invention includes at least one radiation emitter, first and second electrical leads electrically coupled to the radiation emitter, and an integral encapsulant configured to encapsulate the radiation emitter and a portion of the first and second electrical leads. The encapsulant has at least a first zone and a second zone, where the second zone exhibits at least one different characteristic from the first zone. Such different characteristics may be a physical, structural, and/or compositional characteristic. Preferably, the at least one different characteristic includes at least one of the following: mechanical strength, thermal conductivity, thermal capacity, coefficient of thermal expansion, specific heat, oxygen and moisture impermeability, adhesion, and transmittance with respect to radiation emitted from the radiation emitter. The radiation emitter may be in a form of an emitter, and is preferably an LED.

Claims

1. A method of making a radiation emitting device comprising the steps of:

attaching and electrically coupling at least one radiation emitter to a lead frame to form a subassembly;

inserting said subassembly into a mold cavity;

partially filling the mold cavity with a first encapsulant material;

filling the remainder of the mold cavity with a second encapsulant material; and

removing the encapsulated subassembly from the mold cavity.

2. The method of claim 1 further comprising the step of applying a glob top to said at least one radiation emitter prior to inserting said subassembly into a mold cavity.

3. The method of claim 1 further comprising the step of partially curing the first encapsulant material before filling the remainder of the mold cavity with the second encapsulant material.

4. The method of claim 1 and further including the step of curing the first and second encapsulant materials before removing the encapsulated subassembly from the mold cavity.

5. The method of claim 1 wherein the first encapsulant material is substantially transparent to radiation emitted by the radiation emitter.

6. The method of claim 1 wherein said second encapsulant material is opaque.

7. A radiation emitter method of manufacture comprising the steps of:

providing at least one subassembly comprising a lead frame and at least one radiation emitter electrically connected to said lead frame;

encapsulating a first portion of said subassembly with a first encapsulant material; and

encapsulating a second portion of said subassembly with a second encapsulant material having at least one different characteristic than said first encapsulant material, wherein said at least one different characteristic is selected from the group comprising;

cohesion, mechanical compression strength, mechanical tensile strength, thermal conductivity, specific heat, coefficient of thermal expansion, adhesion, oxygen permeability, gas permeability, moisture permeability, transmittance, glass transition temperature and microcrystalline structure.

8. The method of claim 7 wherein said at least one different characteristic is thermal conductivity.

9. The method of claim 7 further comprising the step of applying a glob top to said at least one radiation emitter prior to encapsulating said at least one radiation emitter.

10. The method of claim 7 wherein the first encapsulant material is substantially transparent to radiation emitted by the radiation emitter.

11. The method of claim 7 wherein said second encapsulant material is opaque.

12. A radiation emitter method of manufacture comprising the steps of:

providing a plurality of interconnected subassemblies, each subassembly comprising a lead frame and at least one radiation emitter electrically connected to said lead frame;

encapsulating a first portion of said subassemblies with a first encapsulant material; and

encapsulating a second portion of said subassemblies with a second encapsulant material having at least one different characteristic than said first encapsulate material.

13. The method of claim 12 further comprising the step of applying a glob top to said at least one radiation emitter prior to encapsulating said at least one radiation emitter.

14. The method of claim 12 further comprising the step of singulation of said subassemblies subsequent to encapsulating said first and second portions.

15. The method of claim 12 wherein the first encapsulant material is substantially transparent to radiation emitted by the radiation emitter.

16. The method of claim 12 wherein said second encapsulant material is opaque.