# US 2020/0404792 A1 · Systems and methods for etching of metals

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- Number: US 2020/0404792 A1
- Document ID: US20200404792A1
- Status: Published application
- Kind: A1
- Application number: 16/896,554
- Filed: 2020-06-09
- Published: 2020-12-24
- Earliest claimed: 2019-06-18
- Assignees: D-Wave Systems Inc.
- Applicants: D-Wave Systems Inc.
- Inventors: Jeffrey P. Burress; Richard D. Neufeld; Surjit Singh Dhesi
- Web page: https://patentgrep.com/patent/US20200404792A1

## CPC

- H05K 3/067: {Etchants}
- H05K 1/09: Use of materials for the {conductive, e.g. } metallic pattern
- H05K 3/064: {Photoresists}
- H10N 60/01: Manufacture or treatment
- H05K 2201/0338: Layered conductor, e.g. layered metal substrate, layered finish layer or layered thin film adhesion layer
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

A method of fabricating a multilayer superconducting printed circuit board comprises first, forming a bimetal foil to overlie a substrate, the bimetal foil comprising a first layer of a first metal, a layer of a second metal, and a second layer of the first metal, and then etching the second layer of the first metal. Forming a bimetal foil to overlie a substrate may include forming a bimetal foil comprising a first layer of a normal metal, a layer of a superconducting metal, and a second layer of the normal metal. Etching the second layer of the first metal may include preparing a patterned image in the second layer of the first metal for etching, processing the patterned image through a cleaner, rinsing the patterned image, and then, immersing the patterned image in a microetch.

## Claims

### Claim 1

A method of fabricating a multilayer superconducting printed circuit board, the method comprising:
first, forming a bimetal foil to overlie a substrate, the bimetal foil comprising a first layer of a first metal, a layer of a second metal, and a second layer of the first metal; and
then etching the second layer of the first metal.

### Claim 2 (depends on 1)

The method of claim 1, wherein the etching the second layer of the first metal includes:
preparing a patterned image in the second layer of the first metal for etching;
processing the patterned image through a cleaner;
rinsing the patterned image; and
then, immersing the patterned image in a microetch.

### Claim 3 (depends on 2)

The method of claim 2, wherein the processing the patterned image through a cleaner includes processing the patterned image through the cleaner, the cleaner comprising a surfactant.

### Claim 4 (depends on 3)

The method of claim 3, wherein the processing the patterned image through the cleaner includes processing the patterned image through the cleaner, the cleaner which further includes de-ionized water and sulfuric acid.

### Claim 5 (depends on 2)

The method of claim 2, wherein the immersing the patterned image in a microetch includes immersing the patterned image in the microetch, the microetch which includes a catalyst and a first stabilizer.

### Claim 6 (depends on 5)

The method of claim 5, wherein the immersing the patterned image in the microetch, the microetch which includes the catalyst and the first stabilizer includes immersing the patterned image in the microetch, the microetch which includes tungsten and 1, 6 hexanediol.

### Claim 7 (depends on 6)

The method of claim 6, wherein the immersing the patterned image in the microetch includes immersing the patterned image in the microetch, the microetch which further includes de-ionized water, sulfuric acid, hydrogen peroxide, and sodium hydroxybenzene sulfonate.

### Claim 8 (depends on 1)

The method of claim 1, wherein the forming a bimetal foil to overlie a substrate includes forming the bimetal foil to overlie an electrically insulative substrate.

### Claim 9 (depends on 8)

The method of claim 8, wherein the etching the second layer of the first metal includes:
preparing a patterned image in the second layer of the first metal for etching;
processing the patterned image through a cleaner;
rinsing the patterned image; and,
after the processing the patterned image through a cleaner and the rinsing the patterned image, immersing the patterned image in a microetch.

### Claim 10 (depends on 8)

The method of claim 8, wherein the forming the bimetal foil to overlie an electrically insulative substrate includes forming the bimetal foil to overlie at least one of a polyimide or a polytetrafluoroethylene (PTFE) composite.

### Claim 11 (depends on 10)

The method of claim 10, wherein the etching the second layer of the first metal includes:
preparing a patterned image in the second layer of the first metal for etching;
processing the patterned image through a cleaner;
rinsing the patterned image; and
after the processing the patterned image through a cleaner and the rinsing the patterned image, immersing the patterned image in a microetch.

### Claim 12 (depends on 1)

The method of claim 1, wherein the forming a bimetal foil to overlie a substrate, the bimetal foil comprising a first layer of a first metal, a layer of a second metal, and a second layer of the first metal includes forming the bimetal foil to overlie the substrate, the bimetal foil comprising a first layer of a normal metal, a layer of a superconducting metal, and a second layer of the normal metal.

### Claim 13 (depends on 12)

The method of claim 12, wherein the etching the second layer of the first metal includes:
preparing a patterned image in the second layer of the first metal for etching;
processing the patterned image through a cleaner;
rinsing the patterned image; and
after the processing the patterned image through a cleaner and the rinsing the patterned image, immersing the patterned image in a microetch.

### Claim 14 (depends on 12)

The method of claim 12, wherein the forming the bimetal foil to overlie the substrate, the bimetal foil comprising the first layer of the normal metal, the layer of the superconducting metal, and the second layer of the normal metal includes forming the bimetal foil to overlie the substrate, the bimetal foil comprising a first layer of copper, a layer of aluminum, and a second layer of copper.

### Claim 15 (depends on 14)

The method of claim 14, wherein the etching the second layer of the first metal includes:
preparing a patterned image in the second layer of the first metal for etching;
processing the patterned image through a cleaner;
rinsing the patterned image; and
after the processing the patterned image through a cleaner and the rinsing the patterned image, immersing the patterned image in a microetch.

### Claim 16 (depends on 14)

The method of claim 14, wherein the forming the bimetal foil to overlie the substrate, the bimetal foil comprising the first layer of copper, the layer of aluminum, and the second layer of copper includes:
at least partially copper-plating the substrate to form a copper-plated substrate;
at least partially aluminum-plating the copper-plated substrate to form a superconductive substrate; and
at least partially copper-plating the superconductive substrate.

### Claim 17 (depends on 16)

The method of claim 16, wherein the etching the second layer of the first metal includes:
preparing a patterned image in the second layer of the first metal for etching;
processing the patterned image through a cleaner;
rinsing the patterned image; and
then, immersing the patterned image in a microetch.