Flexible printed circuit board and method for manufacturing same

Patent metadata

Field	Value
Publication number	US-10285260-B2
Application number	US-201514927888-A
Country	US
Kind code	B2
Filing date	Oct 30, 2015
Priority date	Nov 21, 2014
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

The flexible printed circuit board includes a base layer, a first circuit layer and a second circuit layer, the first circuit and the second circuit layer formed on both sides of the base layer; conducting holes extending through the base layer and the first copper layer, the conducting holes include annular copper ring embedded in the first circuit layer. A height difference between a surface of the annular copper ring and a surface of the first circuit layer is in a range from 0 to 3 micrometers. A method for manufacturing the flexible printed circuit board is also provided.

First claim

What is claimed is:

1. A method for manufacturing a flexible printed circuit board, comprising:
providing a substrate comprising a base layer, a first copper layer and a second copper layer, the first copper formed at one side of the base layer, and the second copper layer formed at an opposite side of the base layer;
forming a first hole extending through the base layer and the first copper layer, a bottom of the first hole sealed by the second copper layer;
posting dry films on the first copper layer and the second copper layer;
removing part of the dry films which corresponding to the part of the first hole on the first copper layer, to expose part of the first copper layer, wherein the first hole is surrounded by the exposed first copper layer and presented with a ring shape;
reducing a thickness of the copper of the exposed first copper layer to form a second hole on the first copper layer, which is communicated with the first hole;
partial plating copper at the first and the second hole to form an annular copper ring and a conducting hole, the plated copper of the conducting hole directly contacting a surface of the second copper layer facing the base layer, a surface of the annular copper ring being at a same level with a surface of the first copper layer; and
removing the dry films, and processing the first copper layer to form a circuit layer, to form the flexible printed circuit board.

2. The method of claim 1 , wherein a height difference between the surface of the annular copper ring and the surface of the first copper layer is in the range from 0 to 3 micrometers.

3. The method of claim 1 , further comprising: receiving shadows or organic conducting coating treatment procedure before posting the dry films.

Assignees

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

Inventors

• Hu xian-qin
• Li yan-lu
• ZHANG Li-bo

Classifications

• H05K2201/09472

  Recessed pad for surface mounting; Recessed electrode of component · CPC title

• H05K3/4623

  the circuit boards having internal via connections between two or more circuit layers before lamination, e.g. double-sided circuit boards (H05K3/462 takes precedence) · CPC title

• H05K2201/09845

  Stepped hole, via, edge, bump or conductor · CPC title

• H05K1/115

  Via connections; Lands around holes or via connections (H05K1/112 takes precedence) · CPC title

• H05K3/4015

  using auxiliary conductive elements, e.g. pieces of metal foil, metallic spheres · CPC title