Coupon wafer and method of preparation thereof

Patent metadata

Field	Value
Publication number	US-2023117282-A1
Application number	US-202117911111-A
Country	US
Kind code	A1
Filing date	Mar 16, 2021
Priority date	Mar 17, 2020
Publication date	Apr 20, 2023
Grant date	—

Abstract

A coupon wafer comprising a device coupon (110) for use in a micro-transfer printing process used to fabricate an optoelectronic device. The coupon wafer includes a wafer substrate (124), and the device coupon (110) is attached to the wafer substrate via a tether (122) and the tether (122) is formed from a dielectric material.

First claim

1 . A coupon wafer comprising a device coupon for use in a micro-transfer printing process used to fabricate an optoelectronic device, wherein
the coupon wafer includes a wafer substrate, and the device coupon is attached to the wafer substrate via a tether; and wherein the tether comprises a dielectric material.

2 . The coupon wafer of claim 1 , wherein the tether extends across a surface of the device coupon and across a portion of an upper surface of the wafer substrate.

3 . The coupon wafer of claim 1 , wherein the tether is a multi-layered tether.

4 . The coupon wafer of claim 3 , wherein the tether includes a layer of silicon nitride or a layer of silicon oxide.

5 . The coupon wafer of claim 3 , wherein the tether includes: a layer of silicon nitride and a layer of photoresist; a layer of silicon oxide and a layer of photoresist; or a layer of silicon nitride, a layer of silicon oxide, and a layer of photoresist.

6 . The coupon wafer of claim 1 , wherein the tether has a thickness of at least 20 nm and no more than 500 nm.

7 . The coupon wafer of claim 1 , wherein the device coupon includes an anti-reflective coating, and the tether is at least partially provided by the anti-reflective coating.

8 . The coupon wafer of claim 1 , further comprising a sacrificial layer, located between the device coupon and the wafer substrate.

9 . The coupon wafer of claim 8 , wherein the tether extends down a sidewall of the device coupon, across a portion of an upper surface of the sacrificial layer, down a sidewall of the sacrificial layer, and across a portion of an upper surface of the wafer substrate.

10 . The coupon wafer of claim 1 , further comprising a gap, between the device coupon and the wafer substrate.

11 . The coupon wafer of claim 10 , wherein the tether extends down a sidewall of the device coupon, above a portion of an upper surface of the wafer substrate, and down to contact the wafer substrate.

12 . The coupon wafer of claim 1 , wherein the tether comprises a first region which extends down a vertical side of the device coupon towards the wafer substrate, and a second region which extends horizontally away from the device coupon.

13 . The coupon wafer of claim 1 , wherein the coupon wafer comprises a raised platform above which the device coupon is located, wherein the tether extends beyond the raised platform and along a sidewall thereof.

14 . The coupon wafer of claim 1 , the coupon wafer comprising:
a channel, being bounded on one side by a surface of the device coupon and on an opposite side by a sidewall of the coupon wafer; and wherein the tether extends across a surface of the device coupon, and across the channel to contact one or more sidewalls of the coupon wafer.

15 . The coupon wafer of claim 14 , wherein a portion of the tether extending across the channel is narrower than an adjacent portion of tether.

16 . The coupon wafer of claim 14 , wherein the channel extends around the entire perimeter of the device coupon.

17 . The coupon wafer of claim 1 , wherein the tether includes one or more apertures therethrough.

18 . A method of preparing a coupon wafer for use in a micro-transfer printing process, the coupon wafer comprising a device coupon used to fabricate an optoelectronic device, wherein the method comprises:
depositing a tether across a surface of the device coupon to attach the device coupon to a wafer substrate of the coupon wafer; wherein the tether comprises a dielectric material.

19 . The method of claim 18 , wherein the method further comprises:
a filling step, performed before depositing the tether, of at least partially filling a channel with a filling material, the channel being bounded on one side by a surface of the device coupon and on an opposite side by a sidewall of the coupon wafer, and an etching step, performed after depositing the tether, of removing the filling material, leaving a gap between the device coupon and one or more sidewalls of the coupon wafer.

20 . A method of micro-transfer printing, using the coupon wafer of claim 1 , comprising steps of:
adhering the device coupon to a stamp, and lifting it away from the coupon wafer; and depositing the device coupon on a platform wafer, thereby forming an optoelectronic device.

21 . An optoelectronic device, formed using the method of claim 20 .

Assignees

• Rockley Photonics Ltd

Inventors

• Dernaika Mohamad
• Peters Frank
• Yu Guomin

Classifications

• H10P72/7428

  used to support diced chips prior to mounting · CPC title

• H10P95/112

  leaving a reusable substrate, e.g. epitaxial lift off · CPC title

• H10P72/74 Primary

  using temporarily an auxiliary support · CPC title

• H10W74/014

  using batch processing · CPC title

• H10W72/0198

  batch processes · CPC title