JPH07102400A - Plating device and current value deciding method - Google Patents

Abstract

PURPOSE:To provide a plating device in which the thickness and dispersion of plating can be controlled and uniformized even in the case the shape and area of the object to be plated in accordance with divided anodes are different and to provide a method for deciding current value. CONSTITUTION:An anode by which the object 4 to be plated is applied with plating in a plating tank 3 is divided, they are partitioned by bulkheads 5 to form into divided anodes 6 respectively, the surface of the object 4 to be plated is subdivided into small sections in accordance with the divided anodes 6, the area to be plated in practice is found per small section, the relationship between the size of the area to be plated and the current value is represented by a fuzzy rule in accordance with a rule of thumb, and the membership function of the position of each small section to the area to be plated and the membership function of the plating current value per small section are found. By practicing fazzy inference in accordance with fazzy knowredge contg. the same all membership functions, the plating current value for applying electric current to the divided anode per small section is decided, and a current value setting command 8 is given to plural current sources 1 in a power source part 2 from a control part 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating apparatus and a current value determining method, and more particularly to a plating apparatus and a current value determining method for plating a multilayer ceramic substrate.

[0002]

2. Description of the Related Art As a conventional plating apparatus, for example, in the case of the invention disclosed in Japanese Patent Laid-Open No. 61-281894, a split anode 41 is an object to be plated as shown in the circuit diagram of FIG. It is unavoidable in the case of plating with one anode by providing corresponding to a printed circuit board terminal, providing a current detector 42 and a changeover switch 43 in series, and switching between a power feeding circuit 44 and a resistance circuit 45. The unevenness of the plating thickness depending on the location of the terminal is made uniform by controlling it for each terminal (for each pin), so that the maximum current density can be increased and the plating can be performed accordingly. It has the effect of shortening the processing time.

[0003]

Although the conventional plating apparatus described above can control the current value for each divided anode, the adjustment of the current value in this case is only for the plating object having the same shape. With the aim of controlling the variation in the plating thickness with respect to the target, if the shape and area of the plating target corresponding to the split anodes are different, then the experiment (trial and error) must be repeated to get closer to the target. However, there is a problem that it cannot be easily handled.

The object of the present invention is to determine a plating apparatus and a current value which can control and make uniform the thickness variation of the plating even when the shape and area of the plating object corresponding to the divided anodes are different. To provide a method.

[0005]

The plating apparatus of the present invention comprises:
A power supply unit including a plurality of current sources each having a current value setting function, an electrode unit that divides an anode for plating an object to be plated in a plating tank and separates each with partition walls, and uses each as a divided anode, The control unit determines a current value to be set for each of the plurality of current sources included in the power supply unit and issues a current value setting command.

In the method for determining the plating current value of the present invention, the anode for plating the object to be plated in the plating tank is divided into partition anodes, and the surfaces of the object to be plated correspond to the divided anodes. Into small sections, determine the area to be actually plated for each small section, and divide each small section according to the position of each small section on the surface of the object to be plated and the area to be plated. This is a configuration for determining the plating current value applied to the anode.

[0007]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention.

The plating apparatus 10 shown in FIG. 1 has a power source unit 2 having a plurality of current sources 1 each of which can individually set a current value, and an electric current supplied from the power source unit 2 to be flowed so that an object to be plated in a plating tank 3 is supplied. 4 includes an electrode section 7 having a plurality of divided anodes 6 separated by partition walls 5 for plating, and a control section 9 for issuing a current value setting command 8 for determining a current value to be set in the current source 1. There is.

FIG. 2 is a flow chart showing the procedure for determining the plating current value set in the current source.

In the procedure for determining the plating current value shown in FIG. 2, in step (hereinafter referred to as S) 11, the area to be plated of the portion of the object 4 to be plated divided into the divided anodes 6 is calculated, and in step S12, the divided anodes are calculated. The fuzzy knowledge defining the relationship of how much current should be applied to each split anode 6 is constructed by considering the split state of 6 and the distribution of the area to be plated of the plating object 4 obtained in S11, and S13 In step S14, fuzzy inference is executed based on the fuzzy knowledge previously constructed, and in step S14, the current value of each divided anode 6 is determined from the conclusion obtained by executing the fuzzy inference first.

In the plating apparatus 10 of one embodiment of the present invention,
When plating the object 4 to be plated, first, consider the total area to be plated of the object 4 to be plated, the target plating film thickness, the plating time, the plating efficiency, the type of metal to be plated, etc. The total current value that the part 2 must flow to the electrode part 7 is calculated.

FIG. 3 is a perspective view for explaining the relative relationship between the object to be plated and the split anode.

The divided anode 6 is vertically divided into 3 by the partition wall 5.
It is divided into a total of 9 parts in the horizontal direction 3, and the names A1 to A9 are given to each. Corresponding to this, the plating target 4
Imaginary subdivisions on the surface of are also labeled P1 to P9.

Taking the case where the electrode portion 7 has the shape shown in FIG. 3 as an example, the procedure for determining the value of the current flowing through each split anode 6 will be described below.

First, in S11, the plating object 4 is also divided into 9 parts according to A1 to A9 of the divided anode 6, and each range is set to P1 to P9 according to the divided anode 6, and plating within each range is performed. Find the area that should be. Since the area to be plated is the area of the wiring pattern in the case of the multilayer ceramic substrate, it can be obtained by using the CAD data when designing the multilayer ceramic substrate. The CAD data is input with information on the coordinates of the start and end points of the wiring pattern and the width of the wiring pattern.
The area to be plated within each range of P9 is obtained. The total area to be plated may be the sum of the areas P1 to P9.

Next, in S12, the relationship between the area to be plated and the current value is expressed by a fuzzy rule such as "if the area to be plated is large, the current is increased" from the empirical rule.
The area to be plated, which is the condition part of this rule, and the current value, which is the conclusion part of the fuzzy rule, are expressed by membership functions to build fuzzy knowledge.
As an empirical rule, the distribution of the plating film thickness when the plating object 4 is plated before is referred to. For example, the plating film thickness is larger in the peripheral portion (ranges P1 to P4, P6 to P9) than in the central portion (range P5) of the object to be plated.

When the plating area in that range is large as compared with the surrounding area, the plating film thickness in that area becomes thin. There is such a thing. Consider fuzzy rules using this rule of thumb.

The following fuzzy rules are considered. When the area to be plated in each range Pn of the object 4 to be plated in FIG. 3 is expressed as an area Mn and the current value flowing through the anode An is expressed as a current value Cn, the rule for determining the current value C5 flowing through the anode A5 is: If M5 is large and area M2 is large, current value C
5 is very large. If the area M5 is normal and the area M2 is large, the current value C5 is increased. If the area M5 is small and the area M2 is large, the current value C is large.
5 can be medium. Considering the symmetry of the electrodes, the electrodes A1, A3, A7, A9 and the electrodes A2, A4,
By applying the same rule to A6 and A8, the number of rules can be reduced.

In order to perform fuzzy inference using these rules, a fuzzy membership function expressing "large" or "small" is necessary.

FIG. 4 is an explanatory diagram for explaining an example of the fuzzy membership function.

FIG. 4 (a) shows a fuzzy membership function for the area M5 as a condition part. For example, in the expression that the area M5 is large, normal or small, the horizontal axis is the area and the vertical axis is " It is indicated by a relative value of a grade from 0 ”to“ 1.0 ”.

Further, FIG. 4 (b) shows the fuzzy membership function with respect to the current value C5 as the conclusion part, and the horizontal axis represents the relative current value index, which takes a value from "0" to "1.0" and the vertical axis. The axis is graded from "0" to "1.0". The abscissa of the fuzzy membership function in the conclusion part is the relative current value index, that is, the total current value determined in proportion to the total area of the object to be plated 4 and each split anode of the result of fuzzy inference. This is because it is necessary to prevent the total sum of the current values of the above from being inconsistent with each other, and in order to make them coincide with the total current value which is determined in proportion to the total area to be plated by multiplying the relative current values by a constant.

Further, since the influences on the surrounding electrodes are different between the electrodes A1 and A5, the membership function of the expression "increasing" may be different for each electrode.

As described above, in S12, fuzzy knowledge is constructed by these fuzzy rules and fuzzy membership functions.

Then, in S13, based on the fuzzy knowledge obtained in S12, an inference is performed by the Min-Max method which is generally used in the fuzzy inference, and what is the current value of each divided anode 6? The membership function of the conclusion of goodness is derived.

Finally, in S14, the center of gravity is calculated from the membership function of the conclusion obtained in S13, and this value is set as the relative current value of the corresponding divided anode 6, and similarly, the relative current values of all the divided anodes 6 are obtained. Then, the sum of the current values flowing through the divided anodes 6 by multiplying the relative current values of the divided anodes 6 by a certain constant is equal to the total current value determined in proportion to the total area to be plated. To do so.
In this way, the current value of each split anode 6 is determined.

Next, the operation for plating will be described.

It is assumed that the current value to be applied to each split anode 6 has been determined in advance by the procedure for determining the plating current value shown in FIG. 2. First, the plating target 4 and the electrode portion 7 are set in the plating tank 3. Next, the control unit 9 sends a current value setting command 8 to be supplied to each split anode 6 to the power supply unit 2 for each current source 1.
Applies a current having a current value given by the current value setting command 8 to each split anode 6. When the current is supplied for the determined plating time, the control unit 9 sets all the current value setting commands 8 to "0" and finishes the plating. In this way, the plating target 4
To plate.

By using the plating apparatus 10 and the current value determination method as described above, even when the wiring pattern of the plating object 4 has variations in area and distribution, the inside of each small section corresponding to the divided anode 6 is divided. By calculating the area of the wiring pattern and obtaining the current value using empirical fuzzy knowledge, it is possible to perform plating with a good film thickness distribution.

[0031]

As described above, according to the present invention, the anode for plating the object to be plated in the plating tank is divided into partition anodes, and each of the divided anodes is made to correspond to the divided anode. Into small sections,
Obtain the actual plating area for each small section, and determine the plating current value to be applied to the split anode for each small section, corresponding to the position of each small section on the surface of the object to be plated and the area to be plated. As a result, even if the shape or area of the object to be plated corresponding to the divided anodes is different, it is possible to control and make uniform the variation in the plating thickness.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a flowchart showing a procedure for determining a plating current value set in a current source.

FIG. 3 is a perspective view for explaining a relative relationship between an object to be plated and a split anode.

FIG. 4 is an explanatory diagram illustrating an example of a fuzzy membership function.

FIG. 5 is a circuit diagram of a conventional plating apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 current source 2 power supply section 3 plating tank 4 plating object 5 partition wall 6 split anode 7 electrode section 8 current value setting command 9 control section 10 plating device

Claims (4)

[Claims] 1. A power supply unit including a plurality of current sources each having a current value setting function, and an anode for plating an object to be plated in a plating tank are divided into partition walls, and each partition is used as a divided anode. A plating apparatus comprising: an electrode unit; and a control unit that determines a current value to be set for each of a plurality of current sources included in the power supply unit and issues a current value setting command. 2. The plating apparatus according to claim 1, wherein the plurality of current sources and the plurality of divided anodes are connected in a mutually corresponding relationship. 3. An anode for plating an object to be plated in a plating tank is divided into partition anodes, and the surfaces of the object to be plated are divided into small sections corresponding to the divided anodes. Obtain the area to be actually plated for each small section, and set the plating current value to be applied to the divided anode for each small section in correspondence with the position of each small section on the surface of the object to be plated and the area to be plated. A method for determining a plating current value, characterized by determining. 4. An empirical rule is used to determine the plating current value to be applied to the divided anodes for each of the small sections in correspondence with the position of each of the small sections on the surface of the object to be plated and the area to be plated. The relationship between the size of the plated area and the current value is expressed by a fuzzy rule in accordance with the above, and a membership function for the plated area at the position of each small section and a membership function for the plating current value for each small section are obtained. 4. The plating current value to be applied to the divided anode for each of the small sections is determined by executing fuzzy inference based on fuzzy knowledge including all of these membership functions. Plating current value determination method.