Flexible devices and methods using laser lift-off

Patent metadata

Field	Value
Publication number	US-2019348573-A1
Application number	US-201815975656-A
Country	US
Kind code	A1
Filing date	May 9, 2018
Priority date	May 9, 2018
Publication date	Nov 14, 2019
Grant date	—

Abstract

A method of making a flexible device comprises providing a rigid substrate and a flexible substrate, disposing a layer of print adhesive on the rigid substrate, and micro-transfer printing micro-devices onto the print adhesive. Each of the micro-devices comprises a micro-device substrate separate, independent, and distinct from the rigid substrate and from the flexible substrate. A bonding layer is provided to bond the flexible substrate to the micro-devices such that (i) the bonding layer is disposed between the flexible substrate and the micro-devices and (ii) the micro-devices are disposed between the rigid substrate and the flexible substrate (e.g., forming a device structure). The flexible substrate is separated from the rigid substrate so that the micro-devices remain bonded to the flexible substrate providing a flexible device. The micro-devices can comprise at least a portion of a micro-device tether.

First claim

1 . A method of making a flexible device, comprising:
providing a rigid substrate and a flexible substrate; disposing a layer of print adhesive on the rigid substrate; transfer printing micro-devices onto the print adhesive, wherein each of the micro-devices comprises a micro-device substrate separate, independent, and distinct from the rigid substrate and from the flexible substrate; providing a bonding layer; bonding the flexible substrate to the micro-devices with the bonding layer such that (i) the bonding layer is disposed between the flexible substrate and the micro-devices and (ii) the micro-devices are disposed between the rigid substrate and the flexible substrate; and separating the flexible substrate from the rigid substrate so that the micro-devices remain bonded to the flexible substrate, wherein separating the flexible substrate from the rigid substrate comprises exposing the print adhesive to electromagnetic radiation and dissociating the rigid substrate from the micro-devices, from the bonding layer, and from the bonded flexible substrate.

2 . (canceled)

3 . The method of claim 1 , wherein the rigid substrate is glass, quartz, sapphire, or a semiconductor, wherein the flexible substrate is plastic, or wherein the rigid substrate is glass, quartz, sapphire, or a semiconductor and the flexible substrate is plastic.

4 . The method of claim 1 , wherein the micro-devices comprise a first micro-device comprising one or more first material(s) and a second micro-device comprising one or more second material(s) that are different from the one or more first material(s).

5 . The method of claim 1 , wherein each of the micro-devices comprises at least a portion of a micro-device tether.

6 . The method of claim 1 , comprising micro-transfer printing each micro-device from a native micro-device source wafer to the print adhesive disposed on the rigid substrate, thereby breaking, fracturing, or separating at least one micro-device tether,
wherein, prior to the micro-transfer printing, each of the micro-devices is physically connected to the native micro-device source wafer by the at least one micro-device tether.

7 . The method of claim 1 , wherein each of the micro-devices is an inorganic micro-light-emitting diode (micro-iLED) and the micro-device substrate is a micro-iLED substrate separate, independent, and distinct from the rigid substrate, from the flexible substrate, and from any other micro-iLED substrate.

8 . The method of claim 1 , wherein each of the micro-devices comprises two or more micro-elements disposed on the micro-device substrate and each of the two or more micro-elements comprises a micro-element substrate separate, independent, and distinct from the rigid substrate, from the flexible substrate, from the micro-device substrate, and from any other micro-element substrate.

9 . The method of claim 8 , wherein each micro-element of the one or more micro-elements comprises at least a portion of a micro-element tether.

10 . The method of claim 9 , comprising micro-transfer printing each of the one or more micro-elements from a native micro-element source wafer to the micro-device substrate, thereby breaking or separating at least one micro-element tether,
wherein, prior to the micro-transfer printing, each of the one or more micro-elements is physically connected to the native micro-element source wafer by the at least one micro-element tether.

11 . The method of claim 10 , comprising micro-transfer printing each micro-device from a native micro-device source wafer to the print adhesive, thereby breaking or separating at least one micro-device tether,
wherein, prior to the micro-transfer printing, each micro-device is physically connected to a native micro-device source wafer with the at least one micro-device tether.

12 . The method of claim 8 , wherein the micro-devices are pixels and one or more of the one or more micro-elements are inorganic micro-light-emitting diodes (micro-iLEDs), and for each of the one or more micro-elements that is an inorganic micro-iLED, the micro-element substrate is a micro-iLED substrate separate, independent, and distinct from the rigid substrate, from the flexible substrate, from the pixel substrate, and from any other micro-iLED substrate.

13 . The method of claim 12 , wherein each of the micro-devices comprises a micro-controller and the method comprises micro-transfer printing the micro-controller from a native micro-controller source wafer to the micro-device substrate of the micro-device, thereby breaking at least one micro-controller tether or separating at least one micro-controller tether,
wherein, prior to the micro-transfer printing the micro-controller is physically connected to a native micro-controller source wafer with the at least one micro-controller tether and the micro-controller comprises a micro-controller substrate separate, independent, and distinct from the rigid substrate, from the flexible substrate, from the micro-device substrate, from any micro-iLED substrate, and from any other micro-controller substrate.

14 . The method of claim 8 , wherein the one or more micro-elements comprises a first micro-element comprising one or more first material(s) and a second micro-element comprising one or more second material(s) that are different from the one or more first material(s).

15 . The method of claim 1 , comprising disposing electrical conductors on the flexible substrate.

16 . The method of claim 14 , wherein each of the micro-devices comprises one or more connection posts extending away from the micro-device substrate electrically connected to a micro-device circuit and the method comprises electrically connecting each connection post of the one or more connection posts to an electrical conductor by micro-transfer printing and bonding the micro-devices to the flexible substrate.

17 . The method of claim 15 , wherein the micro-devices each comprise electrical contacts electrically connected to the micro-device circuits and the method comprises electrically connecting the electrical contacts of each of the micro-devices to the electrical conductors on the flexible substrate.

18 . The method of claim 17 , comprising forming vias through the bonding layer and forming at least one electrical connection through the vias.

19 . The method of claim 1 , wherein the micro-devices each comprise micro-device contact pads and the method comprises disposing electrical conductors on the bonding layer and electrically connecting the electrical conductors to the micro-device contact pads.

20 - 22 . (canceled)

23 . The method of claim 1 , wherein transfer printing micro-devices onto the print adhesive comprising micro-transfer printing the micro-devices onto the print adhesive.

24 . The method of claim 1 , wherein the print adhesive is an epoxy.

25 . A method of making a flexible device, comprising:
providing a rigid substrate and a flexible substrate; disposing a layer of print adhesive on the rigid substrate; transfer printing micro-devices onto the print adhesive, wherein each of the micro-devices comprises a micro-device substrate separate, independent, and distinct from the rigid substrate and from the flexible substrate; providing a bonding layer; bonding the flexible substrate to the micro-devices with the bonding layer such that (i) the bonding layer is disposed between the flexible substrate and the micro-devices and (ii) the micro-devices are disposed betw

Assignees

• X Celeprint Ltd

Inventors

• Raymond Brook
• Bower Christopher Andrew
• Cok Ronald S
• Meitl Matthew

Classifications

• H10W72/0198

  batch processes · CPC title

• H10W90/00

  Package configurations · CPC title

• H10P72/74

  using temporarily an auxiliary support · CPC title

• H10P72/744

  Details of chemical or physical process used for separating the auxiliary support from a device or a wafer · CPC title

• H10P72/7426

  used as a support during build up manufacturing of active devices · CPC title