Method for manufacturing circuit board

Patent metadata

Field	Value
Publication number	US-10653011-B2
Application number	US-201715817052-A
Country	US
Kind code	B2
Filing date	Nov 17, 2017
Priority date	Oct 13, 2017
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

A method for manufacturing the circuit board comprises following steps of providing an insulating substrate, and defining at least one through-hole on the insulating substrate to extending through two opposite surfaces of the insulating substrate; forming a silver layer on each of the two opposite surfaces, and forming a silver conductive structure in each through-hole connecting the silver layers; forming a copper wiring layer on the silver layers to cover each silver conductive structure and a portion region of the silver layers; and etching the silver layers to form a silver wiring layer corresponding to the copper wiring layer, wherein a first etching liquid, which does not etch the copper wiring layer, is used for etching the silver layers.

First claim

What is claimed is:

1. A method for manufacturing the circuit board comprising:
providing an insulating substrate, and defining at least one through-hole on the insulating substrate to extend through two opposite surfaces of the insulating substrate;
forming a silver layer on each of the two opposite surfaces, and forming a silver conductive structure in each of the at least one through-hole connecting the silver layers;
forming a copper wiring layer on the silver layers to cover each silver conductive structure and a portion region of the silver layers; and
etching the silver layers to form a silver wiring layer corresponding to the copper wiring layer, wherein a first etching liquid, which does not etch the copper wiring layer, is used for etching the silver layers; a width of each line of the silver wiring layer is less than a width of a corresponding line of the copper wiring layer, and a spacing between two lines of the silver wiring layer is greater than a spacing between two corresponding lines of the copper wiring layer.

2. The method of the claim 1 , wherein the silver layers and the at least one silver conductive structure are formed by the following steps:
coating a silver paste with nano silver particles on the opposite surfaces of the insulating substrate and the at least one through-hole; and
heating to cure the silver paste with nano silver particles, thereby forming a silver layer on each of the two opposite surfaces, and forming a silver conductive structure in each of the at least one through-hole to connect each silver layer.

3. The method of the claim 2 , wherein a diameter of each nano silver particle is less than 100 nm.

4. The method of the claim 1 , wherein each silver layer has a thickness of about 0.15 μm to about 0.3 μm.

5. The method of the claim 1 , wherein the copper wiring layer is formed by the following steps:
forming a photosensitive layer on a side of each silver layer away from the insulating substrate to cover the silver layer and each silver conductive structure;
exposing and etching two photosensitive layers to form a pattern on the photosensitive layers to expose each silver conductive structure and a portion region of two silver layers, the pattern comprising an opening corresponding to each silver conductive structure;
forming a copper wiring layer corresponding to the pattern to cover each silver conductive structure and the portion region of the silver layers; and
peeling the photosensitive layers exposed and etched off.

6. The method of the claim 1 , wherein after etching the silver layers to form the silver wiring layer corresponding to the copper wiring layer, the method further comprises:
etching the insulating substrate which is not covered by the copper wiring layers with a second etching liquid, to remove the remained silver layers after forming the silver wiring layer;
wherein the second etching liquid, which does not etch the copper wiring layer and the silver wiring layer, is used for etching the insulating substrate.

Assignees

• Hongqisheng Prec Electronics Qinhuangdao Co Ltd
• Avary Holding Shenzhen Co Ltd

Inventors

• Hu xian-qin
• Yang Mei
• Dai Jun

Classifications

• H05K3/067

  Etchants · CPC title

• H05K3/38

  Improvement of the adhesion between the insulating substrate and the metal · CPC title

• H05K2201/0341

  Intermediate metal, e.g. before reinforcing of conductors by plating · CPC title

• C23F1/02

  Local etching · CPC title

• H05K3/4053

  by thick-film techniques · CPC title