Package structure of full color LED form by overlap cascaded die bonding

• US 20030047742A1
• Filed: 11/15/2001
• Published: 03/13/2003
• Est. Priority Date: 09/11/2001
• Status: Active Grant

• Current Assignee: Chang Hsiu Hen
• Original Assignee: Chang Hsiu Hen
• Inventors: Hen, Chang Hsiu
• Granted Patent: US 6,563,139 B2
• Time in Patent Office: Days
• US Class Current: 257/89
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 25/0756 Stacked arrangements of devices
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

The present invention discloses a light source of full color LED (light emitted diode) by using die bond and packaging technology. A first mono-color LED chip with reflective metal on the bottom and transparent metal-oxide on the top of the chip is bonded on the PC board by thermal or ultrasonic die bond. A second mono-color LED chip with reflective metal on both sides is bonded in cascade on the first LED chip by thermal or ultrasonic die bond. The first LED chip emits light through the transparent metal-oxide to mix with the second LED light such that a different color light will obtain. The reflective metal reflects all the light to enforce the light intensity. In near field application, a red, a blue and a green LED are die bond in cascade to get a white light or full color light. In far field application, a yellow and a blue LED are die bond in cascade on the PC board, in its side is another cascaded die bond of a red and a green LED to get a white light or full color light.

Claims

1. A full color LED packaging structure containing three primary color LED dice bond in cascaded, by using a reflective metal layer and a transparent conductive layer to overlap bond the red, blue and green LED dice in cascaded on a pc-board, comprising:

(a) a pc-board, wherein a reflective metal layer is deposited and patterned to form a die bonding pad, a red LED positive bonding pad, a blue LED positive bonding pad, a green light positive bonding pad and a common ground bonding pad;

(b) a first red LED die having a transparent conductive layer of positive electrode and a reflective metal layer of negative electrode, the red LED die is directly overlap bond to the die bonding pad of the pc-board;

(c) a second blue LED die having a transparent conductive layer of positive and negative electrode, the blue LED die is directly overlap bond in cascaded on the red LED die;

(d) a third green LED die having a transparent conductive layer of positive and negative electrode, the green LED die is directly overlap bond in cascaded on the blue LED die;

(e) a plurality of bonding wires for electrically connecting the positive and negative bonding pads of the red LED die, the blue LED die and the green LED die to the positive bonding pads and the common ground bonding pad on the pc-board respectively.

2. The full color LED packaging structure according to claim 1, wherein the red LED die is a pn-junction diode form by epitaxy a p-type InGaP on an n-type GaAs substrate, the size of the die is 400 μ

m to 1000 μ

m rectangular;

3. The full color LED packaging structure according to claim 1, wherein a rectangular reflective metal layer is deposited on one side of the positive electrode of the red LED die to form the positive bonding pad of the red LED, and for reflecting the red light.

4. The full color LED packaging structure according to claim 1, wherein the blue LED die is a pn-junction diode form by epitaxy a p-type InGaN/p-type InGaN on a transparent sapphire substrate, the size of the die is 300 μ

m to 900 μ

m rectangular.

5. The full color LED packaging structure according to claim 1, wherein a square reflective metal layer is deposited on one side of the positive electrode of the blue LED die to form a positive bonding pad of the blue LED, and for reflecting the red and blue light, a rectangular strip of p-type InGaN is etch away and a reflective metal is deposited to form a negative bonding pad.

6. The full color LED packaging structure according to claim 1, wherein the green LED die is a pn-junction diode form by epitaxy an n-type InGaN/p-type InGaN on a transparent sapphire substrate, the size of the die is 200 μ

m to 800 μ

m square.

7. The full color LED packaging structure according to claim 1, wherein a square reflective metal layer is deposited on one side of the positive electrode of the green LED die to form the positive bond pad of the green LED, and for reflecting the red, blue and green light, a square of p-type InGaN is etch away and a reflective metal is deposited to form a negative bonding pad.

16. The full color LED packaging structure according to claim 1 or 9, wherein the green LED die is a pn-junction diode form by epitaxy a p-type InGaN/p-type InGaN on a transparent sapphire substrate, the size of the die is 200 μ

m to 600 μ

m square

20. The full color LED packaging structure according to claim 1, 9, or 19, wherein the reflective metal layer and bonding pad is aluminum, copper or gold, the thickness of this layer is 1000 Å

to 10000 Å

, the better is 2000 Å

to 5000 Å

.

21. The full color LED packaging structure according to claim 1, 9 or 19, wherein the overlap die bond is thermal bonding by heating to the eutectic point of metal at 450°

C. to 550°

C.

22. The full color LED packaging structure according to claim 1, 9 or 19, wherein the transparent conductive layer is Indium oxide (In₂O₃) or other transparent conductive materials, with thickness of 200 Å

to 10000 Å

, the better of 500 Å

to 1000 Å

.

23. The full color LED packaging structure according to claim 1, 9 or 19, wherein the square reflective metal positive and negative bonding pad is aluminum, copper or gold, with width of 50 μ

m to 200 μ

m, the better of 100 μ

m.

24. The full color LED packaging structure according to claim 1, 9 or 19, wherein the overlap bond is ultrasonic bonding.

25. The full color LED packaging structure according to claim 1, 9 or 19, wherein the overlap bonding is by transparent epoxy adhesion.

8. A bias method of an overlap cascaded three primary color LEDs packaging structure, having adjusting bias for supplying the red LED, the blue LED and green LED separately to adjust the color by changing the light intensity of each LED.

9. A full color LED packaging structure containing a blue LED die on a yellow LED die in parallel side-by-side with another green LED die on a red LED die, by using a reflective metal layer and a transparent conductive layer to bond the yellow LED die to a pc-board and the blue LED die is overlap cascaded bond to the yellow LED die, the red LED die is bond to the pc-board and the green LED die is overlap cascaded bond to the red LED die, comprising:

(a) a pc-board, wherein a reflective metal layer is deposited and patterned to form a die bonding pad, a red LED positive bonding pad, a blue LED positive bonding pad, a yellow LED positive bonding pad, a green LED positive bonding pad and a common ground bonding pad;

(b) a first yellow LED die having a transparent conductive layer of positive electrode and a reflective metal layer of negative electrode, the yellow LED die is directly overlap bond to the die bonding pad of the pc-board;

(c) a second blue LED die having a transparent conductive layer of positive and negative electrodes, the blue LED die is directly overlap bond in cascaded on the yellow LED die;

(d) a third red LED die having a transparent conductive layer of positive and negative electrodes, the red LED die is directly overlap bond to the die bonding pad of the pc-board in one side nearby the yellow and blue LED dice;

(e) a fourth green LED die having a transparent conductive layer of positive and negative electrodes, the green LED die is directly overlap bond in cascaded on the red LED die;

(f) a plurality of bonding wires for electrically connecting the positive and negative bonding pad of the yellow LED die, the blue LED die, the red LED die and green LED die to the positive bonding pads and the common ground bonding pad on the pc-board respectively.

10. The full color LED packaging structure according to claim 9, wherein the yellow LED die is a pn-junction diode form by epitaxy a p-type InGaAlP on an n-type GaAs substrate, the size of the die is 300 μ

m to 1000 μ

m rectangular.

11. The full color LED packaging structure according to claim 9, wherein a rectangular reflective metal layer is deposited on one side of the positive electrode of the yellow LED die to form the positive bond pad of the red LED, and for reflecting the yellow light.

12. The full color LED packaging structure according to claim 9, wherein the blue LED die is a pn-junction diode form by epitaxy a p-type InGaN/p-type InGaN on a transparent sapphire substrate, the size of the die is 200 μ

m to 900 μ

m rectangular.

13. The full color LED packaging structure according to claim 9, wherein a square reflective metal layer is deposited on one side of the positive electrode of the blue LED die to form the positive bond pad of the blue LED, and for reflecting the yellow and blue light, a square of p-type InGaN is etch away and a reflective metal is deposited to form a negative bonding pad.

14. The full color LED packaging structure according to claim 9, wherein the red LED die is a pn-junction diode form by epitaxy a p-type InGaAlP on an n-type GaAs substrate, the size of the die is 300 μ

m to 700 μ

m rectangular.

15. The full color LED packaging structure according to claim 9, wherein a rectangular reflective metal layer is deposited on one side of the positive electrode of the red LED die to form the positive bond pad of the red LED, and for reflecting the red light.

17. The full color LED packaging structure according to claim 9, wherein a square reflective metal layer is deposited on one side of the positive electrode of the blue LED die to form the positive bond pad of the blue LED, and for reflecting the red and green light, a square of p-type InGaN is etch away and a reflective metal is deposited to form a negative bonding pad.

18. A bias method of an overlap cascaded blue LED on yellow LED and green LED on red LED package structure, having adjusting bias for supplying the yellow, blue, red and green LED separately to adjust the color by changing the light intensity of each LED.

19. A full color LED packaging structure containing a first LED die and a second complementary LED die, by using a reflective metal layer and a transparent conductive layer, the first LED die is bond to a pc-board and the second complementary LED die is overlap cascaded bond to the first LED die, comprising:

(a) a pc-board, wherein a reflective metal layer is deposited and patterned to form a die bonding pad, a first LED positive bonding pad, a second complementary LED positive bonding pad and a common ground bonding pad;

(b) a first LED die having a transparent conductive layer of positive electrode and a reflective metal layer of negative electrode, the first LED die is directly overlap bond to the die bonding pad of the pc-board;

(c) a second complementary LED die having a transparent conductive layer of positive and negative electrodes, the blue LED die is directly overlap bond in cascaded on the yellow LED die;

(d) a plurality of bonding wires for electrically connecting the positive and negative bonding pads of the first LED die and the second complementary LED die to the positive bonding pads and the common ground bonding pad on the pc-board respectively.