# US 10,874,016 B2 · Method of manufacturing physical structure for high frequency signal transmission

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- Number: US 10,874,016 B2
- Document ID: US10874016B2
- Status: Granted
- Kind: B2
- Application number: 16/577,062
- Filed: 2019-09-20
- Published: 2020-01-09
- Granted: 2020-12-22
- Earliest claimed: 2016-06-07
- Assignees: Avary Holding (Shenzhen) Co., Limited.; HongQiSheng Precision Electronics (QinHuangDao) Co., Ltd.
- Applicants: Avary Holding (Shenzhen) Co., Limited.; HongQiSheng Precision Electronics (QinHuangDao) Co., Ltd.
- Inventors: Ming-Jaan Ho; Hsiao-Ting Hsu
- Web page: https://patentgrep.com/patent/US10874016B2

## CPC

- H05K 1/0237: {High frequency adaptations (H05K1/0216 takes precedence)}
- H05K 3/06: the conductive material being removed chemically or electrolytically, e.g. by photo-etch process {(semi-additive methods H05K3/108)}
- H05K 3/108: {by semi-additive methods; masks therefor (characterised by metallic etch mask H05K3/062; electroplating methods or apparatus H05K3/241)}
- H05K 3/188: {by direct electroplating}
- H05K 1/0326: {containing O}
- H05K 1/09: Use of materials for the {conductive, e.g. } metallic pattern
- H05K 3/244: {Finish plating of conductors, especially of copper conductors, e.g. for pads or lands (selective plating methods H05K3/243; finish plating of conductors made by printing techniques H05K3/246; solder as finish H05K3/3465)}
- Y10T 29/49155: Manufacturing circuit on or in base
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A method for fabricating a sandwiched structure of silver-copper-silver functioning as a high frequency signal transmission structure includes an insulating sheet and a conductive circuit on the insulating sheet. The conductive circuit includes a silver conductive layer bonded to the insulating sheet, a copper conductive layer formed on the silver conductive layer, and a silver covering layer laid to cover top and side surfaces of the copper conductive layer. The silver conductive layer and the silver covering layer together enclose the copper conductive layer and the higher conductivity of the silver together with the skin effect improves high-frequency transmission efficiency of the copper.

## Claims

### Claim 1

A method of manufacturing a high frequency signal transmission structure, comprising:
providing an insulating sheet, forming a silver bottom layer on the insulating sheet;
forming a copper conductive layer on a part of the silver bottom layer;
removing the silver bottom layer which is not covered by the copper conductive layer; and
forming a silver covering layer on the copper conductive layer, wherein the copper conductive layer is surrounded by the silver bottom layer and the silver covering layer, the silver bottom layer, the copper conductive layer and the silver covering layer cooperatively form a conductive circuit, the copper conductive layer is a core of the conductive circuit, and the silver conductive layer and the silver covering layer cooperatively form a cladding layer wrapping the core of the conductive wiring layer.

### Claim 2 (depends on 1)

The method of claim 1, wherein the silver bottom layer is formed on the insulating sheet by vacuum evaporation.

### Claim 3 (depends on 2)

The method of claim 2, wherein the copper conductive layer is formed by electroplating.

### Claim 4 (depends on 3)

The method of claim 3, wherein forming the copper conductive layer comprising:
forming a dry film on the silver bottom layer;
exposing and developing the dry film to deform a pattern of the copper conductive layer;
electroplating a copper layer on the silver bottom layer to form the copper conductive layer, and
removing the dry film.

### Claim 5 (depends on 1)

The method of claim 1, wherein the insulating sheet is made from polyester polymer, polynaphthalene dicarboxylic acid glycol ester, polyimide, or polyterephthalate.

### Claim 6 (depends on 5)

The method of claim 5, wherein the pre-treating of the surface of the insulating sheet comprising: hydrolyzing an ester group comprised in the insulating sheet is into carboxyl; and changing the carboxyl (—COOH) into ester ions (—COO—) in an alkaline environment.

### Claim 7 (depends on 1)

The method of claim 1, wherein before evaporating a silver bottom layer on the insulating sheet, further comprising pre-treating a surface of the insulating sheet.

### Claim 8 (depends on 1)

The method of claim 1, wherein the silver bottom layer not covered by the copper conductive layer is removed by etching with an alkaline solution.

### Claim 9 (depends on 1)

The method of claim 1, wherein a thickness of the silver conductive layer is same as a thickness of the silver covering layer.

### Claim 10 (depends on 1)

The method of claim 1, wherein a thickness of the silver conductive layer is approximately 0.1 μm to 2 μm.

### Claim 11 (depends on 1)

The method of claim 1, wherein an electrical conductivity of the cladding layer is larger than an electrical conductivity of the core.

### Claim 12 (depends on 1)

The method of claim 1, wherein the silver covering layer is formed by a sterling silver method.

### Claim 13 (depends on 1)

The method of claim 1, wherein a side surface of the silver conductive layer is covered by the silver covering layer.