Flip chip integration on qubit chips

Patent metadata

Field	Value
Publication number	US-10355193-B2
Application number	US-201715823675-A
Country	US
Kind code	B2
Filing date	Nov 28, 2017
Priority date	Nov 28, 2017
Publication date	Jul 16, 2019
Grant date	Jul 16, 2019

Abstract

A quantum bit (qubit) flip chip assembly may be formed when a qubit it formed on a first chip and an optically transmissive path is formed on a second chip. The two chips may be bonded using solder bumps. The optically transmissive path may provide optical access to the qubit on the first chip.

First claim

What is claimed is:

1. A method for forming a quantum bit (qubit) flip-chip assembly, the method comprising:
forming a qubit on a first chip;
forming an optically transmissive path in a second chip; and
bonding the first chip to the second chip; and
wherein the optically transmissive path is located above the qubit.

2. The method of claim 1 , wherein the path has an aperture with a diameter large enough to allow for treatment of the qubit.

3. The method of claim 1 , wherein the optically transmissive path has an aperture of 100 microns or less.

4. The method of claim 1 , further comprising laser annealing the qubit by applying a laser through a surface of the qubit chip that is opposite the second chip.

5. The method of claim 1 , further comprising ion etching the qubit.

6. The method of claim 1 , wherein the forming the optically transmissive path comprises drilling, using a high-power laser beam, the second chip to form a through-hole in the second chip.

7. The method of claim 6 , wherein the etching comprises deep-reactive ion etching.

8. The method of claim 6 , wherein the etching comprises a chemical etch, and wherein the chemical etch is a tetramethylammonium hydroxide (TMAH) etch.

9. The method of claim 1 , wherein the forming the optically transmissive path comprises etching a through-hole in the second chip.

10. The method of claim 1 , wherein the second chip comprises a transparent substrate.

11. The method of claim 10 , wherein the transparent substrate is Magnesiumoxide (MgO).

12. A flip chip apparatus comprising:
a first chip comprising a qubit;
a second chip bonded to the first chip, wherein the first chip and the second chip are bonded by a plurality of solder bumps; and
wherein an optically transmissive path in the second chip provides for optical access to the qubit on the first chip.

13. The apparatus of claim 12 , wherein the second chip comprises a transparent substrate.

14. The apparatus of claim 13 , wherein the transparent substrate is sapphire.

15. The apparatus of claim 12 , wherein the optically transmissive path has a diameter large enough to allow for treatment of one or more of the plurality of qubits.

16. The apparatus of claim 12 , wherein the qubit is accessible for laser annealing via the optically transmissive path.

17. The apparatus of claim 12 , wherein the optically transmissive path of the second chip is aligned with the qubit on the first chip.

18. The apparatus of claim 12 , wherein the optically transmissive path is formed with a chemical etch.

19. The apparatus of claim 12 , wherein the optically transmissive path is formed using a high-power laser beam.

20. The apparatus of claim 12 , wherein the first chip is comprised of a transparent substrate.

Assignees

• IBM

Inventors

• Rosenblatt Sami
• Orcutt Jason S
• Sandberg Martin O
• Brink Markus
• Adiga Vivekananda P
• Bronn Nicholas T

Classifications

• H10W90/722

  between stacked chips · CPC title

• H10W90/297

  characterised by the through-semiconductor vias [TSVs] in the stacked chips · CPC title

• H10W90/295

  optical coupling · CPC title

• H10W72/07236

  Soldering or alloying · CPC title

• H10W72/07232

  Compression bonding, e.g. thermocompression bonding · CPC title