Compliant micro device transfer head

• US 9,505,230 B2
• Filed: 05/17/2016
• Issued: 11/29/2016
• Est. Priority Date: 05/08/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Bibl, Andreas, Higginson, John A., Hu, Hsin-Hua
• Primary Examiner(s): Caputo, Lisa
• Assistant Examiner(s): PLUMB, NIGEL H
• Application Number:
  US15/157,247
• Publication Number:
  US 20160257131A1
• Time in Patent Office: 196 Days
• Field of Search: 735/143.2, 735/141.6, 735/140.1, 734/88, 347/159, 347/111
• US Class Current: 1/1
• CPC Class Codes: B25J 15/0052 multiple gripper units or multiple end effectors
• CPC Class Codes: B25J 15/0085 with means for applying an electrostatic force on the object to be gripped
• CPC Class Codes: B41J 2/385 characterised by selective supply of electric current or selective application of magnetism to a printing or impression-transfer material B41J2/005 takes precedence
• CPC Class Codes: B41J 2/39 using multi-stylus heads
• CPC Class Codes: B81B 2201/038 Microengines and actuators not provided for in B81B2201/031 - B81B2201/037
• CPC Class Codes: B81C 99/002 Apparatus for assembling MEMS, e.g. micromanipulators micromanipulators per se B25J7/00
• CPC Class Codes: H01L 21/67144 Apparatus for mounting on conductive members, e.g. leadframes or conductors on insulating substrates
• CPC Class Codes: H01L 21/6835 using temporarily an auxiliary support
• CPC Class Codes: H01L 2221/68322 Auxiliary support including means facilitating the selective separation of some of a plurality of devices from the auxiliary support
• CPC Class Codes: H01L 2221/68354 used to support diced chips prior to mounting
• CPC Class Codes: H01L 2221/68363 used in a transfer process involving transfer directly from an origin substrate to a target substrate without use of an intermediate handle substrate
• 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 2221/68381 Details of chemical or physical process used for separating the auxiliary support from a device or wafer
• CPC Class Codes: H01L 2224/29036 covering only the central area of the surface to be connected
• CPC Class Codes: H01L 2224/29101 the principal constituent melting at a temperature of less than 400°C
• CPC Class Codes: H01L 2224/2919 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/7565 Means for transporting the components to be connected
• 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 2224/83815 Reflow soldering
• CPC Class Codes: H01L 2224/83855 : Hardening the adhesive by curing, i.e. thermosetting
• 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 24/97 : 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 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 2924/12041 : LED
• CPC Class Codes: H01L 33/0093 : Wafer bonding; Removal of the growth substrate

Abstract

A compliant micro device transfer head and head array are disclosed. In an embodiment a micro device transfer head includes a spring portion that is deflectable into a space between a base substrate and the spring portion.

Claims

1. An electrostatic transfer method comprising:

positioning an array of compliant electrostatic transfer heads over an array of micro devices;

contacting the array of micro devices with the array of compliant electrostatic transfer heads;

sensing contact of the array of micro devices with the array of compliant electrostatic transfer heads;

applying a voltage to the array of compliant electrostatic transfer heads to create a grip pressure for each compliant electrostatic transfer head;

picking up the array of micro devices with the array of compliant electrostatic transfer heads; and

releasing the array of micro devices onto a receiving substrate.

2. The electrostatic transfer method of claim 1, wherein sensing contact of the array of micro devices with the array of compliant electrostatic transfer heads comprises sensing strain with a sensor.

3. The electrostatic transfer method of claim 2, wherein sensing strain comprises measuring a change in voltage with the sensor.

4. The electrostatic transfer method of claim 2, wherein the sensor is located along a spring member that deflects when contacting the array of micro devices with the array of compliant electrostatic transfer heads.

5. The electrostatic transfer method of claim 2, wherein each compliant electrostatic transfer head includes a mesa structure that deflects toward a base substrate upon contacting the array of micro devices with the array of compliant electrostatic transfer heads.

6. The electrostatic transfer method of claim 2, wherein applying the voltage to the array of compliant electrostatic transfer heads comprises applying bi-polar voltages to the array of compliant electrostatic transfer heads.

7. The electrostatic transfer method of claim 2, further comprising sensing contact of the receiving substrate with the array of micro devices with the sensor.

8. The electrostatic transfer method of claim 1, wherein sensing contact of the array of micro devices with the array of compliant electrostatic transfer heads comprises sensing strain with a plurality of sensors.

9. The electrostatic transfer method of claim 8, wherein sensing strain comprises measuring a change in voltage with each sensor.

10. The electrostatic transfer method of claim 8, wherein each sensor is located along a separate spring member that deflects when contacting the array of micro devices with the array of compliant electrostatic transfer heads.

11. The electrostatic transfer method of claim 8, wherein each compliant electrostatic transfer head includes a mesa structure that deflects toward a base substrate upon contacting the array of micro devices with the array of compliant electrostatic transfer heads.

12. The electrostatic transfer method of claim 8, wherein applying the voltage to the array of compliant electrostatic transfer heads comprises applying bi-polar voltages to the array of compliant electrostatic transfer heads.

13. The electrostatic transfer method of claim 12, wherein each micro device is a micro LED device.

14. The electrostatic transfer method of claim 13, wherein each micro LED device has a maximum width of 1 to 100 μ

m.

15. The electrostatic transfer method of claim 14, wherein each mesa structure has a maximum width of 1 to 100 μ

m.

16. The electrostatic transfer method of claim 15, wherein a pitch of the array of compliant electrostatic transfer heads is an integer multiple of a pitch of the array of micro devices.

17. The electrostatic transfer method of claim 8, further comprising sensing contact of the receiving substrate with the array of micro devices with the plurality of sensors.

18. The electrostatic transfer method of claim 1, comprising applying the voltage to the array of compliant electrostatic transfer heads to create the grip pressure for each compliant electrostatic transfer head prior to contacting the array of micro devices with the array of compliant electrostatic transfer heads.