Micro device transfer head heater assembly and method of transferring a micro device

• US 9,463,613 B2
• Filed: 06/17/2014
• Issued: 10/11/2016
• Est. Priority Date: 11/18/2011
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Bibl, Andreas, Higginson, John A., Law, Hung-Fai Stephen, Hu, Hsin-Hua
• Primary Examiner(s): Chan, Sing P
• Application Number:
  US14/307,321
• Publication Number:
  US 20140290867A1
• Time in Patent Office: 847 Days
• Field of Search: 156/230, 156/235, 156/241, 156/249, 156/273.1, 156/273.7, 156/711, 156538-542, 156/556, 156/558, 156/569, 156/583.1, 156/583.4, 156/583.7, 156/752
• US Class Current: 1/1
• CPC Class Codes: B32B 38/18 Handling of layers or the laminate
• CPC Class Codes: H01L 21/67144 Apparatus for mounting on conductive members, e.g. leadframes or conductors on insulating substrates
• CPC Class Codes: H01L 2221/68368 used in a transfer process involving at least two transfer steps, i.e. including an intermediate handle substrate
• CPC Class Codes: H01L 2224/75252 in the upper part of the bonding apparatus, e.g. in the bonding head
• CPC Class Codes: H01L 2224/75725 in the upper part of the bonding apparatus, e.g. in the bonding head
• CPC Class Codes: H01L 2224/7598 specially adapted for batch processes
• CPC Class Codes: H01L 2224/83 using a layer connector
• CPC Class Codes: H01L 2224/83005 being a temporary or sacrificial substrate
• CPC Class Codes: H01L 2224/95001 involving a temporary auxiliary member not forming part of the bonding apparatus, e.g. removable or sacrificial coating, film or substrate
• 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 24/75 Apparatus for connecting with bump connectors or layer connectors
• CPC Class Codes: H01L 24/83 using a layer connector
• CPC Class Codes: H01L 24/95 at chip-level, i.e. with connecting carried out on a plurality of singulated devices, i.e. on diced chips
• CPC Class Codes: H01L 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 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 29/167 further characterised by the doping material H01L29/1604 takes precedence
• 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 2924/10253 Silicon [Si]
• CPC Class Codes: H01L 2924/10329 Gallium arsenide [GaAs]
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/1421 : RF devices
• CPC Class Codes: H01L 2924/1431 : Logic devices
• CPC Class Codes: H01L 2924/1434 : Memory
• CPC Class Codes: H01L 2924/1461 : MEMS
• CPC Class Codes: H01L 2933/0066 : relating to arrangements for conducting electric current to or from the semiconductor body
• 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: Y10T 156/1153 : Temperature change for delamination [e.g., heating during delaminating, etc.]
• CPC Class Codes: Y10T 156/17 : Surface bonding means and/or assemblymeans with work feeding or handling means
• CPC Class Codes: Y10T 156/1705 : Lamina transferred to base from adhered flexible web or sheet type carrier
• CPC Class Codes: Y10T 156/1707 : Discrete spaced laminae on adhered carrier
• CPC Class Codes: Y10T 156/1744 : Means bringing discrete articles into assembled relationship
• CPC Class Codes: Y10T 156/1749 : All articles from single source only
• CPC Class Codes: Y10T 156/1776 : Means separating articles from bulk source
• CPC Class Codes: Y10T 156/1911 : Heating or cooling delaminating means [e.g., melting means, freezing means, etc.]

Abstract

A method of transferring a micro device and an array of micro devices are disclosed. A carrier substrate carrying a micro device connected to a bonding layer is heated to a temperature below a liquidus temperature of the bonding layer, and a transfer head is heated to a temperature above the liquidus temperature of the bonding layer. Upon contacting the micro device with the transfer head, the heat from the transfer head transfers into the bonding layer to at least partially melt the bonding layer. A voltage applied to the transfer head creates a grip force which picks up the micro device from the carrier substrate.

Claims

1. A transfer head assembly comprising:

a base substrate supporting an array of electrostatic transfer heads;

wherein each electrostatic transfer head comprises a mesa structure of 1 to 100 μ

m scale in both x and y dimensions; and

a heater assembly to transfer heat through the base substrate to each electrostatic transfer head.

2. The transfer head assembly of claim 1, wherein the heater assembly comprises a heating element.

3. The transfer head assembly of claim 1, further comprising a dielectric layer covering the mesa structure of each electrostatic transfer head.

4. The transfer head assembly of claim 3, wherein each mesa structure is integrally formed with the base substrate.

5. The transfer head assembly of claim 3, wherein the dielectric layer is 0.5-2.0 μ

m thick.

6. The transfer head assembly of claim 3, wherein each mesa structure is 1-5 μ

m thick.

7. The transfer head assembly of claim 1, wherein each electrostatic transfer head incorporates a monopolar electrode configuration.

8. The transfer head assembly of claim 1, wherein each electrostatic transfer head incorporates a bipolar electrode configuration.

9. The transfer head assembly of claim 8, wherein each electrostatic transfer head comprises a pair of mesa structures, with each mesa structure of 1 to 100 μ

m scale in both x and y dimensions.

10. The transfer head assembly of claim 9, wherein each mesa structure is integrally formed with the base substrate.

11. The transfer head assembly of claim 10, wherein each mesa structure and the base substrate comprise silicon.

12. The transfer head assembly of claim 11, further comprising a dielectric layer covering the pair of mesa structures of each electrostatic transfer head.

13. The transfer head assembly of claim 12, wherein the dielectric layer comprises Al₂O₃.

14. The transfer head assembly of claim 12, wherein the dielectric layer comprises Ta₂O₅.

15. The transfer head assembly of claim 9, wherein each electrostatic transfer head comprises a trench that separates the pair of mesa structures.

16. The transfer head assembly of claim 1, wherein each electrostatic transfer head is configured to apply a separate electrostatic grip pressure to a separate micro device of 1 to 100 μ

m scale.

17. The transfer head assembly of claim 1, wherein the heater assembly further comprises a heat distribution plate.