Method for controlling plating layer thickness distribution in FPC making process

Abstract

The invention discloses a method for controlling the thickness distribution of a clad layer in the process of manufacturing an FPC, Especially a first electroplating area with an opening is formed on the coating film of each FPC single product during the process of manufacturing the FPC, and a second electroplating area with an opening is formed simultaneously on the outside of the first electroplating area and on the coating films. The method can improve the equal distribution of current and overcome the relatively strong edge effect, thereby achieving the control of the thickness distribution of the clad layer; besides, the invention presents good operability and no influence on the production cost.

Description

technical field [0001] The invention relates to a surface treatment stage in the manufacturing process of a flexible circuit board (FPC), especially a method for controlling the thickness distribution of a plating layer in the electroplating process in this stage. Background technique [0002] As we all know, in the manufacturing process of FPC, it is mainly divided into three stages: circuit formation, surface treatment and shape formation. Taking single-sided FPC as an example, in the surface treatment stage, it is divided into whole surface, cover film hot pressing (or Printing solder resist ink), surface coating treatment and other processes. Among them, the final result of the cover film hot pressing (or printing solder resist ink) process is to form a number of openings on the cover film on the etched circuit according to the product performance requirements, so that the etched circuit needs to be used to connect other The interface part of the component is exposed, a...

AI Technical Summary

Problems solved by technology

Due to the large area of ​​the electroplated product, there is a large difference in the electroplating area between the edge of the product and the center of the product, resulting in a strong edge effect, which will cause a large difference in the thickness of the nickel layer between the edge of the product and the center of the product (please refer to figure 1 ), this is because the current (the direction shown by the arrow in the figure) is introduced from the two contact points 1 and 2 on the product, which will form an edge effect—that is, after the product is energized, the current density at the middle position 90 is small, The current density at positions 10, 20, 30, 40, 50, 60, 70, and 80 around the product is high, and under the same process conditions (current density, current magnitude, time), the thickness of the nickel plating layer at the position with high current density It must be thick, and the thickness of the nickel plating layer at the position where the current density is small must be thin, so that the thickness distribution of the nickel plating layer is not uniform

The traditional method of controlling the thickness distribution of the nickel layer is by adjusting the current magnitude and current density in the electroplating nickel process parameters. This control method can no longer meet the requirements for products with a smaller range of nickel layer thickness distribution.

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