Transfer-bonding method for light emitting devices

• US 9,306,117 B2
• Filed: 12/27/2014
• Issued: 04/05/2016
• Est. Priority Date: 07/25/2011
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Wu, Ming-Hsien, Chu, Ying-Chien, Wang, Shih-Hao, Fang, Yen-Hsiang, Chu, Mu-Tao
• Primary Examiner(s): HUBER, ROBERT T
• Application Number:
  US14/583,594
• Publication Number:
  US 20150111329A1
• Time in Patent Office: 465 Days
• Field of Search: 257/89, 257/E33.001, 438/34, 438/35
• US Class Current: 1/1
• CPC Class Codes: H01L 2224/95 at chip-level, i.e. with connecting carried out on a plurality of singulated devices, i.e. on diced chips
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 27/153 in a repetitive configuration, e.g. LED bars
• 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
• CPC Class Codes: H01L 33/0095 Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

A transfer-bonding method for light emitting devices including following steps is provided. A plurality of light emitting devices is formed over a first substrate and is arranged in array, wherein each of the light emitting devices includes a device layer and an interlayer sandwiched between the device layer and the first substrate. A protective layer is formed over the first substrate to selectively cover parts of the light emitting devices, and other parts of the light emitting devices are uncovered by the protective layer. The device layers uncovered by the protective layer are bonded with a second substrate. The interlayers uncovered by the protective layer are removed, so that parts of the device layers uncovered by the protective layer are separated from the first substrate and are transfer-bonded to the second substrate.

Claims

1. A transfer-bonding method for light emitting devices comprising:

(a) providing a first substrate having an elastic interlayer formed thereon and forming a plurality of light emitting devices arranged in array over the elastic interlayer;

(b) providing a second substrate having a mask layer formed thereon, wherein an area of the second substrate is exposed by the mask layer;

(c) bonding the first substrate and the second substrate, such that parts of the light emitting devices are bonded with the area of the second substrate exposed by the mask layer and the light emitting devices are pressed to embedded in the elastic interlayer by the second substrate, wherein a bonding strength between the parts of the light emitting devices and the second substrate is greater than an adhesion between the parts of the light emitting devices and the elastic interlayer; and

(d) separating the elastic interlayer from the parts of the light emitting devices bonded with the second substrate, such that the parts of the light emitting devices are transfer-bonded to the second substrate.

2. The transfer-bonding method for light emitting devices as recited in claim 1, wherein Young'"'"'s Module (E) of the elastic interlayer ranges from 640 KPa to 2 MPa.

3. The transfer-bonding method for light emitting devices as recited in claim 1, wherein a material of the elastic interlayer comprises polydimethylsiloxane (PDMS).

4. The transfer-bonding method for light emitting devices as recited in claim 1, wherein a thickness of each of the light emitting devices is T1, a thickness of the elastic interlayer is T2, and 2≦

(T2/T1).

5. The transfer-bonding method for light emitting devices as recited in claim 1, wherein the second substrate comprises a plurality of bonding pads formed thereon and parts of the bonding pads are exposed by the mask layer.

6. The transfer-bonding method for light emitting devices as recited in claim 5, wherein the size of the bonding pad is larger than or equal to the size of the light emitting devices.

7. The transfer-bonding method for light emitting devices as recited in claim 5, further comprising:

before bonding the first substrate and the second substrate, forming a plurality of conductive bumps over the bonding pads exposed by the mask layer.

8. The transfer-bonding method for light emitting devices as recited in claim 7, wherein parts of the light emitting devices are bonded to the exposed area of the second substrate through the conductive bumps.

9. The transfer-bonding method for light emitting devices as recited in claim 5, wherein parts of the light emitting devices are bonded with the bonding pad uncovered by the mask layer when parts of the light emitting devices are bonded with the area of the second substrate exposed by the mask layer.

10. The transfer-bonding method for light emitting devices as recited in claim 9, the light emitting device bonded with the bonding pad is located at a higher horizontal level while the light emitting devices in contact with the mask layer are located at a lower horizontal level.

11. The transfer-bonding method for light emitting devices as recited in claim 1, wherein a material of the mask layer comprises polyimide, silicon nitride, silicon oxide, photoresist or BCB (bisbenzocyclobutene).

12. The transfer-bonding method for light emitting devices as recited in claim 1, wherein the elastic interlayer deforms when the light emitting devices are pressed and are embedded in the elastic interlayer.

13. The transfer-bonding method for light emitting devices as recited in claim 1, wherein elastic-resilience of the elastic interlayer occurs after the elastic interlayer is separated from the parts of the light emitting devices bonded with the second substrate.

14. The transfer-bonding method for light emitting devices as recited in claim 1, further comprising:

before bonding the first substrate and the second substrate, forming a plurality of conductive bumps over the light emitting devices.

15. The transfer-bonding method for light emitting devices as recited in claim 14, the conductive bumps are formed over at least part of the light emitting devices.

16. The transfer-bonding method for light emitting devices as recited in claim 1, further comprising:

repeating the step (a) to the step (d) at least one time to transfer light emitting devices capable of emitting different color from different first substrates to the second substrate.

17. The transfer-bonding method for light emitting devices as recited in claim 1, wherein the size of light emitting devices are about 1 micro-meter to about 100 micro-meters.