Printed circuit board and method for manufacturing printed circuit board

Patent metadata

Field	Value
Publication number	US-11304309-B2
Application number	US-201917048806-A
Country	US
Kind code	B2
Filing date	Mar 7, 2019
Priority date	May 11, 2018
Publication date	Apr 12, 2022
Grant date	Apr 12, 2022

Abstract

A printed circuit board according to an embodiment of the present disclosure includes a base film having an insulating property, and a conductive pattern that is stacked on at least one surface of the base film and that includes a plurality of wiring parts arranged in parallel. The plurality of wiring parts have an average width of 5 μm or more and 15 μm or less. The plurality of wiring parts have an electroless plating layer and an electroplating layer stacked on the electroless plating layer. A void density at an interface between the electroless plating layer and the electroplating layer in a section of the plurality of wiring parts in a thickness direction is 0.01 μm2/μm or less.

First claim

The invention claimed is:

1. A printed circuit board comprising:
a base film having an insulating property; and
a conductive pattern that is stacked on at least one surface of the base film and that includes a plurality of wiring parts arranged in parallel,
wherein the plurality of wiring parts have an average width of 5 μm or more and 15 μm or less,
the plurality of wiring parts have an electroless plating layer and an electroplating layer stacked on the electroless plating layer, and
a void density at an interface between the electroless plating layer and the electroplating layer in a section of the plurality of wiring parts in a thickness direction is 0.01 μm 2 /μm or less.

2. The printed circuit board according to claim 1 , wherein a maximum area of a void formed at the interface is 0.01 μm 2 or less.

3. The printed circuit board according to claim 1 , wherein an average spacing of the plurality of wiring parts is 5 μm or more and 15 μm or less.

4. The printed circuit board according to claim 1 , wherein the electroless plating layer and the electroplating layer contain copper as a main component.

5. A method for manufacturing a printed circuit board, comprising a step of forming, by a semi-additive method, a conductive pattern including a plurality of wiring parts arranged in parallel on at least one surface of a base film having an insulating property,
wherein the step of forming includes
an electroless plating step of subjecting the one surface of the base film to electroless plating,
a resist pattern-forming step of forming a resist pattern having an inverted shape of the plurality of wiring parts on a surface of an electroless plating layer formed in the electroless plating step,
a plasma treatment step of subjecting surfaces of the resist pattern and the electroless plating layer after the resist pattern-forming step to plasma treatment, and
an electroplating step of subjecting the surface of the electroless plating layer after the plasma treatment step to electroplating,
the plurality of wiring parts have an average width of 5 μm or more and 15 μm or less, and
an amount of ashing of the resist pattern through the plasma treatment step is 60 nm or more and 300 nm or less.

6. The method for manufacturing a printed circuit board according to claim 5 , wherein an initial current density in the electroplating step is 0.003 A/m 2 or more and 0.015 A/m 2 or less.

7. The printed circuit board according to claim 1 , wherein the void density is 0.001 μm 2 /μm or more and 0.01 μm 2 /μm or less.

8. The printed circuit board according to claim 1 , wherein a void is formed at the interface.

9. The printed circuit board according to claim 8 , wherein a maximum area of the void formed at the interface is 0.01 μm 2 or less.

10. The printed circuit board according to claim 8 , wherein a maximum area of the void formed at the interface is 0.001 μm 2 or more and 0.01 μm 2 or less.

Assignees

• Sumitomo Electric Industries

Inventors

• Sakai Shoichiro
• Imazaki Eiko
• Nitta Koji

Classifications

• C25D5/34

  Pretreatment of metallic surfaces to be electroplated · CPC title

• C25D3/38

  of copper · CPC title

• H05K3/181

  by electroless plating (adhesives therefor H05K3/387) · CPC title

• H05K1/09

  Use of materials for the {conductive, e.g. } metallic pattern · CPC title

• C25D21/12

  Process control or regulation (controlling or regulating in general G05) · CPC title