CN101193501A

CN101193501A - Method for controlling plating layer thickness distribution in FPC making process

Info

Publication number: CN101193501A
Application number: CNA2006101572249A
Authority: CN
Inventors: 代新
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2006-11-30
Filing date: 2006-11-30
Publication date: 2008-06-04

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

Method to control thickness of coating distribution in the FPC manufacture process

Technical field

The present invention relates to the surface treatment stage of flex circuit application (FPC) in the processing and manufacturing process, especially a kind of method of controlling the thickness of coating distribution in the electroplating process in this stage.

Background technology

As everyone knows, FPC mainly is divided into circuit formation, surface treatment and profile and formed for three megastages in the processing and manufacturing process, is example with single face FPC, it is divided into operations such as whole, coverlay hot pressing (or printing welding resistance printing ink), overlay coating processing again in the surface treatment stage.Wherein, coverlay hot pressing (or printing welding resistance printing ink) operation final result, be for coverlay is formed the some openings of formation on the circuit in the demand of foundation properties of product in institute's etching, come out with the interface position that need be used for connecting other components and parts in the circuit that etching is formed, the aforementioned surfaces treatment process then is to handle for the copper foil circuit that will come out carries out overlay coating, preventing that copper oxidation and copper are difficult for problems such as welding, so it can be nickel plating gold or oxygen-proof film processing.At present, the maximum nickel-gold electroplating journey of industry using method in surface treatment.The nickel dam that the nickel-gold electroplating journey obtains as the barrier layer between copper layer and the gold layer, prevents phase counterdiffusion between the Jin Yutong, thereby improves the solderability and the useful life of plank that nickel dam has increased the mechanical strength of golden layer on the other hand on the one hand.

Yet, along with properties of product towards the trend development of reliability more, more and more stricter to the requirement of nickel layer thickness distribution capability.Because the electroplated product area is very big, product edge and product center are electroplated area simultaneously very big difference, thereby produce stronger edge effect, can cause the thickness of product edge and center nickel dam that very big difference (please refer to Fig. 1) is arranged, this is because electric current (direction shown in the arrow among the figure) is two contact points 1 from the product, 2 places import, can form edge effect like this---after the product energising just, the current density in centre position 90 is little, position 10 around the product, 20,30,40,50,60,70,80 current density is big, and in same process conditions (current density, size of current, time) under, its nickel coating thickness of position that current density is big will inevitably be thick, its nickel coating thickness of position that current density is little will inevitably approach, and the thickness distribution of nickel coating is just inhomogeneous like this.The method that traditional control nickel layer thickness distributes is that the product that this control method is littler to the nickel layer thickness distribution can not meet the demands by size of current and current density in the adjusting electronickelling technological parameter.

Summary of the invention

At foregoing, purpose of the present invention promptly is to provide a kind of can overcome stronger edge effect, realizes the control to the thickness of plating layer distribution capability, and the method that distributes of operability control thickness of coating good, that do not influence production cost.

The objective of the invention is to be achieved through the following technical solutions:

The invention provides a kind of method that control thickness of coating in the FPC manufacture process is distributed, especially, form in the operation of opening in first electroplating region in the FPC manufacture process on the coverlay of each FPC Dan Pin, simultaneously on this coverlay and be positioned at the outside of this first electroplating region, form second electroplating region with opening.

In said method, wherein:

The described outside that is positioned at this first electroplating region, the while also is meant the outside of the profile that is positioned at each FPC Dan Pin.

Opening in described second electroplating region is made up of several circular opens.

The present invention electroplates the distribution situation of area according to product, by change design---promptly suitable position increases the circular coverlay opening of different size on product, Copper Foil on the circular coverlay opening part product is exposed, improve and electroplate the even distribution capability of area, thereby improve the even distribution capability of electric current, realize the lifting of nickel layer thickness distribution capability.Compared with prior art, the present invention has following two advantages: first point: the distribution situation according to product is electroplated area, design by change---increase the control method good operability of the circular coverlay opening of different size in position; Second point: circular coverlay opening adopts the mode of boring to process, and can obtain not increasing under operation and the mould, and not only shadow but also has not reduced the production fraction defective to production cost.

Description of drawings

In order to be easy to explanation, the present invention is done to describe in detail by following preferred embodiment and accompanying drawing.

Fig. 1 is that the present invention is to the structural representation in the electroplating process of the method for control thickness of coating distribution in the FPC manufacture process.

Fig. 2 is that the present invention is to the regional structure schematic diagram in the method for control thickness of coating distribution in the FPC manufacture process.

Fig. 3 is the experimental measurement schematic diagram of the present invention to the method for control thickness of coating distribution in the FPC manufacture process.

Embodiment

A kind of method (please refer to Fig. 1) that control thickness of coating in the FPC manufacture process is distributed of the present invention, in order to increase the distributing homogeneity of nickel coating thickness, can be on

product position

10,20,30,40,50,60,70,80 the outside increases some opening a again, b, c, d, e, f, g, h (the shape of these openings, can be processed into circle according to processing conditions, oval, the square arbitrary shape that waits), handle position 10, back like this, 20,30,40,50,60,70,80 change to the inboard that is positioned at product by being positioned at the position around the product before, edge effect just has been added in opening a, b, c, d, e, f, g, the h position, thereby reduced

position

10,20,30,40,50,60,70, the edge effect at 80 places, thus can make being more evenly distributed of nickel coating thickness.

Increase opening in position, just edge effect is farthest reduced, please refer to Fig. 2, if plating face is in zone 3, then can consider in zone 4 or the suitable electroplating region (promptly increasing opening) of regional 5 places increase, reduce the edge effect (in fact just scattered current) in zone 3 greatly, thereby improve the distributing homogeneity of nickel coating thickness.Therefore, that is to say and in the FPC manufacture process, to form in first electroplating region on the coverlay of each FPC Dan Pin (being described regional 3) in the operation of opening, simultaneously on this coverlay and be positioned at the outside of this first electroplating region, formation has second electroplating region of opening, the wherein said outside also can be the outside that is positioned at the profile of each FPC Dan Pin simultaneously, in the process that forms by die-cut formation Dan Pin, the part that can will be formed with second electroplating region of opening is removed with the formation of waste material like this.

Also the present invention is further detailed explanation in conjunction with the accompanying drawings below by specific embodiment.The present invention is after product design is finished, increase the circular coverlay opening of different size in position by NC boring processing mode according to the distribution situation of product plating area, Copper Foil on the circular coverlay opening part product is exposed, improve and electroplate the even distribution capability of area, thereby improve the even distribution capability of electric current, realize the lifting of nickel layer thickness distribution capability.

To product that does not increase circular coverlay opening and the product that has increased circular coverlay opening (being described second electroplating region) in position, adopt same electronickelling process conditions to carry out electronickelling and handle.After the product electronickelling, it is thick to measure its nickel respectively, and instrumentation plan as shown in Figure 3.The thick measurement data of product nickel that does not increase circular coverlay opening is as shown in table 1, and the thick measurement data of product nickel that increases circular coverlay opening in position is as shown in table 2.

Table 1

Table 2

As can be seen from Table 1, do not increase the nickel dam that circular coverlay opening can obtain 2.013 μ m-8.966 μ m.As can be seen from Table 2, increase the nickel dam that circular coverlay opening can obtain 2.418 μ m-4.766 μ m in position.By the comparison of the two, the difference of maximum and minimum value is reduced to 2.348 μ m by 6.953 μ m, realizes the lifting of nickel layer thickness distribution capability effectively, has improved the performance of product.

Claims

1. method that control thickness of coating in the FPC manufacture process is distributed, it is characterized in that: in this FPC manufacture process, wherein form in the operation of opening in first electroplating region on the coverlay of each FPC Dan Pin, simultaneously on this coverlay and be positioned at the outside of this first electroplating region, form second electroplating region with opening.

2. the method that control thickness of coating in the FPC manufacture process is distributed as claimed in claim 1 is characterized in that: the described outside that is positioned at this first electroplating region also refers to be positioned at the outside of the profile of each FPC Dan Pin simultaneously.

3. the method that control thickness of coating in the FPC manufacture process is distributed as claimed in claim 1, it is characterized in that: the opening in described second electroplating region is made up of several circular opens.