Surface mounting method for high power light emitting diode

• US 6,599,768 B1
• Filed: 08/20/2002
• Issued: 07/29/2003
• Est. Priority Date: 08/20/2002
• Status: Expired due to Term

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: United Epitaxy Company, Ltd. (Ennostar, Inc.)
• Inventors: Chen, Tzer-Perng
• Primary Examiner(s): Fahmy, Wael
• Assistant Examiner(s): Trinh, (Vikki) Hoa B.
• Application Number:
  US10/223,244
• Time in Patent Office: 343 Days
• Field of Search: 438/82, 438/85, 438/88, 438/93, 438/98, 438/99, 438/50, 438/64, 438/69, 438/106, 438/110, 438/112, 438/22, 438/24, 438/23, 438/25, 438/113, 362/249
• US Class Current: 438/22
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• 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 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/83 using a layer connector
• 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 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 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/01023 Vanadium [V]
• CPC Class Codes: H01L 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/01047 Silver [Ag]
• CPC Class Codes: H01L 2924/01074 Tungsten [W]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/12041 : LED
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 33/486 : adapted for surface mounting
• 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

Abstract

Disclosed herein is a surface mounting method for high power output light emitting diode (LED). In the first preferred embodiment, the LED is mounted onto a thermal & electrical base-substrate, which has a plurality of trenches formed therein and filled with an insulating layer to isolate two parts of the base-substrate. A reflective frame assembler having a plurality of reflective frame is then adhered to the upper surface of the base-substrate. Each of them is for placing one LED chip. After a LED is with its two electrodes placed on a pair of the first metal contacts, the transparent resin or epoxy is refilled into reflective frame to seal the LED chip. In the second preferred embodiment, the LED is with two electrodes on the different side. Hence the LED is mounted on one metal contact only, the other electrode is in terms of a wire to bond to the other metal contact.

Claims

1. A method of surface mounting for light emitting elements having p-type electrodes and n-type electrodes thereof on one side, said method comprising the steps of:

providing an electrical and thermal conductive substrate;

forming a plurality of trenches in said substrate;

refilling said trenches with an insulating layer;

forming first metal contact pairs on an upper surface of said substrate, wherein each of said first metal contact pairs has one formed on the left hand side and the other formed on the right hand side of each of said trenches for attaching a light emitting element;

backside milling a bottom surface of said substrate until bottoms of said trenches are all exposed, and thus to isolate two first metal contacts for each first metal contact pair;

forming second metal contact pairs on said milled bottom surface, wherein each of said second metal contact pair has one formed on the left hand side and the other formed on the right hand side of each of said trenches for connecting external electrodes;

mounting a reflective frame assembler having a plurality of reflective frame therein on said upper surface, wherein each of said reflective frame corresponds to one light emitting element so that each of said first metal contact pairs has one reflective frame surrounding, and has a central position thereof aligned with a central position of said reflective frame;

placing said light emitting elements each within said reflective frame and having its p-type electrode and n-type electrode, respectively, onto said first metal contact pair which is surrounded by said reflective frame;

sealing said light emitting elements with a transparent resin or epoxy layer within said reflective frame; and

separating said substrate into an individual device, wherein each device has one encapsulated light emitting element therein and has two second metal contact isolated by one trench.

2. The method of claim 1, wherein said electric &

thermal conductive substrate is selected from a material selected from the group consisting of silicon, copper, and aluminum.

3. The method of claim 2, wherein each of said trenches is formed by a lithographic and an etch step to a depth of about 100-500 μ

m.

4. The method of claim 2, wherein each of said trenches is formed by electrodischarge working or laser cutting to a depth of about 100-500 μ

m.

5. The method of claim 1, wherein said insulting layer is selected from spin on glass (SOG) or polyimide or BCB (B-staged bisbenzocyclobutene.

6. A method of surface mounting for light emitting elements having p-type electrodes and n-type electrodes thereof on one side, said method comprising the steps of:

providing an electrical and thermal conductive substrate;

forming a plurality of insulating regions in said substrate, wherein each of said insulating regions is to insulate two metal contacts, which are, respectively, attached to two electrodes of a light emitting element;

forming first metal contact pairs on an upper surface of said substrate, wherein each of said first metal contact pairs, has one formed on the left hand side and the other formed on the right hand side of each of insulating regions for attaching a light emitting element;

forming second metal contact pairs on a bottom surface, wherein each of said second metal contact pair has one formed on the left hand side and the other formed on the right hand side of each of said insulating regions for connecting external electrodes;

mounting a reflective frame assembler having a plurality of reflective frame therein on said upper surface, wherein each of said reflective frame corresponds to one light emitting element so that each of said first metal contact pairs has one reflective frame surrounding, and has a central position thereof aligned with a central position of said reflective frame;

placing said light emitting elements each within said reflective frame and having its p-type electrode and n-type electrode, respectively, onto said first metal contact pair which is surrounded by said reflective frame;

sealing said light emitting elements with a transparent resin or epoxy layer within said reflective frame; and

separating said substrate into an individual device, wherein each device has one encapsulated light emitting element therein and has two second metal contact isolated by one insulating region.

7. The method of claim 6, wherein said electrical and thermal conductive substrate is selected from a material selected from the group consisting of silicon, copper, and aluminum.

8. The method of claim 7, wherein said step of forming a plurality of insulating regions comprises the steps of:

attaching a release film on the first surface, of said base substrate;

forming slits in said base substrate;

refilling said slit with an insulating layer; and

removing said release film.

9. The method of claim 8, wherein said step of forming slits is formed by a lithographic and an etch step until throughout said base substrate.

10. The method of claim 8, wherein said step of forming slits is formed by electrodischarge working or laser cutting until throughout said base substrate.

11. The method of claim 8, wherein said insulting layer is selected from spin on glass (SOG) or polyimide or BCB (B-staged bisbenzocyclobutene).

12. A method of surface mounting for light emitting elements having p-type electrodes and n-type electrodes thereof on different sides, said method comprising the steps of:

providing an electrical and thermal conductive substrate;

cutting a upper surface of said substrate so as to form a plurality of trenches therein;

refilling said trenches with an insulating layer;

forming first metal contact pairs on an upper surface of said substrate, wherein each of said first metal contact pairs, has one formed on the left hand side and the other formed on the right hand side of each of said trenches, and one for attaching a light emitting element, the other for bonding a conductive wire;

backside milling a bottom surface of said substrate until bottoms of said trenches are all exposed, and thus to isolate two first metal contacts for each first metal contact pair;

forming second metal contact pairs on said milled bottom surface, wherein each of said second metal contact pair has one formed on the left hand side and the other formed on the right hand side for each of said trenches for connecting external electrodes;

mounting a reflective frame assembler having a plurality of reflective frame therein on said upper surface, wherein each of said reflective frame corresponds to one light emitting element so that each of said first metal contact pairs has one reflective frame surrounding, and a central position of said reflective frame is substantially aligned with either one first metal contact that said reflective frame surrounds;

placing each one of said light emitting elements within said reflective frame corresponding by attaching its electrode on a bottom surface of said light emitting element to said first metal contact of said first metal contact pair that substantially located at a central position of reflective frame corresponding and its electrode on an upper surface of said light emitting element to the other first metal contact by a bonding wire;

sealing said light emitting element and said bonding wire with a transparent resin or epoxy layer within said reflective frame; and

separating said substrate into an individual device, wherein each device has one encapsulated light emitting element therein and has two second metal electrodes isolated by one trench.

13. The method of claim 12, wherein said electrical and thermal conductive substrate is selected from a material selected from the group consisting of silicon, copper, and aluminum.

14. The method of claim 13, wherein each of said trenches is formed by a lithographic and an etch step to a depth of about 100-500 μ

m.

15. The method of claim 13, wherein each of said trenches is formed by electrodischarge working or laser cutting to a depth of about 100-500 μ

m.

16. The method of claim 12, wherein said insulating layer is selected from spin on glass (SOG) or polyimide or BCB (B-staged bisbenzocyclobutene).