JPH1168293A - Horizontal carriage electric plating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a horizontal carriage electric plating device, capable of performing the plating of uniform film thickness to printed wiring boards in various sizes and shapes. SOLUTION: This device for performing electrical plating, while horizontally holding the printed wiring board 6 inside a plating processing tank 4 is provided with a clamping body 5 for holding one side of the printed wiring board 6, a pair of upper and lower anodes 1 for which a distance from the printed wiring board 6 becomes an equal interval at the time of installing the printed wiring board 6 and an electrically insulated shielding body 2, erected with a prescribed interval from the side opposite to the side held by the clamping body 5 of the printed wiring board 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal transport type electroplating apparatus used in a process for forming a conductive circuit on a printed wiring board.

[0002]

2. Description of the Related Art Conventionally, as a method of electroplating performed in a conductive circuit forming step of a printed wiring board, as shown in FIG. 4, a jig is used while a printed wiring board 6 is held vertically by a transfer robot 12 as shown in FIG. 11 and a method of performing plating in a plating tank 4 filled with a plating solution 9, and as shown in FIGS. And plating while transporting the plating.

[0003]

However, the plating apparatus shown in FIG. 4 involves a complicated operation of attaching the printed wiring board 6 to the jig 11 and removing it after performing the plating process. Therefore, there is a problem that the plating film thickness cannot be made uniform.

[0004] In order to solve the above problems, a device of a horizontal transport system has been developed, but there are many technical problems,
Not widely applied. The technical problem is that it is difficult to control the current distribution according to the printed wiring boards 6 of various sizes and shapes, and it is not possible to satisfy the uniformity of the plating film thickness.

As a method of controlling the current distribution in the horizontal transport system, as shown in FIG. 5, a printed wiring board 6 is held horizontally by a gripping body 5 connected to a transport drive unit 10, In the process of transporting the anode, the anode 1 is divided and installed in a strip shape, and only the anode 1 arranged in the vertical direction of the printed wiring board 6 for electroplating is energized, and the area of the anode 1 to be energized is changed. There is a way to make it happen. However, in this method, there are many gaps between the printed wiring board 6 and the anode 1 and around the anode 1 where current can flow around.
The current tends to concentrate on the end of the printed wiring board 6, and the cross section of the end of the printed wiring board 6 subjected to the plating process becomes as shown in FIG.

Further, as shown in FIG. 6, it has been proposed to dispose an electrically insulating shield 2 in the vicinity of the surplus portion of the anode 1 with respect to the printed wiring board 6 to control the current distribution. However, even with this method, there are many gaps between and around the printed wiring board 6 and the anode 1, and the position where the current concentrates moves only from the end of the printed wiring board 6 to the center. 8, the plating state will be obtained.

The present invention has been made in view of the above problems, and has as its object to provide a horizontal transport electroplating apparatus capable of plating a printed wiring board 6 having various sizes and shapes with a uniform film thickness. And

[0008]

As shown in FIG. 1, the present invention relates to an apparatus for performing electroplating while holding a printed wiring board 6 horizontally in a plating tank 4, wherein one side of the printed wiring board 6 is provided. And a pair of upper and lower anodes 1 and 1 that are equally spaced from the printed wiring board 6 when the printed wiring board 6 is installed, and a printed wiring board 6.
And an electrically insulating shielding body 2 that stands up from the side opposite to the side held by the gripping body 5 at a predetermined interval.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A grip body 5 used in the present invention is:
As shown in FIG. 2, the printed wiring board 6 is conveyed while being close to the inner wall 3 of the plating bath, and serves as a cathode during the plating process. The distance C between the inner wall 3 of the plating bath and the printed wiring board 6 is preferably 30 mm or less, and when the distance C is longer than this, the plating film thickness becomes gradually non-uniform.

The electrically insulating shield 2 used in the present invention
Can be moved left and right on the drawing according to the width dimension of the printed wiring board 6, so that the distance G from the printed wiring board 6 can be kept constant at all times. The distance G between the electrically insulating shield 2 and the printed wiring board 6 is preferably 50 mm or less. If the distance G is larger than this, the plating film thickness becomes gradually non-uniform. In the present invention, the surrounding space between the printed wiring board 6 and the anode 1 is narrowed by the electrically insulating shield 2 so that the current flows directly from the anode 1 to the printed wiring board 6 at the shortest distance.

In addition, the vertical height L of the electrically insulating shielding body 2 is such that the relationship between the distance H between the vertically arranged anodes 1 and 1 satisfies L ≧ H / 2. It is preferable for forming a film thickness.

The above-mentioned C, G and L are preferable for minimizing the gap where the current flows from the anodes 1 and 1 at the end of the printed wiring board 6 where the current tends to concentrate, and forming a uniform plating film thickness. The range is shown, and as these three conditions are satisfied, a more uniform plating film thickness can be formed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings.
FIG. 3 is a plan view showing a main part of the present invention. The printed wiring board 6 is held horizontally by a gripper 5 attached to a drive motor 7 and a transport drive unit 10, and is transferred to a plating tank 4. Conveyed. As shown in FIG. 1, the printed wiring board 6 is continuously transported and plated between pulleys 8 installed above and below the printed wiring board 6 for stabilizing the posture in the plating bath 4. .

The criteria for determining the uniformity of the plating film thickness are as follows:
Standard deviation (σ) is generally used, and the plating film thickness is set to 20
As a condition for depositing μm, σ is required to be 2 or less. Using the horizontal transport electroplating apparatus of the present invention shown in FIG. 1 and performing various experiments while changing the values of C, G and L, the distance C between the plating processing tank inner wall 3 and the printed wiring board 6, The relationship between the standard deviation (σ) and the distance G between the electrically insulating shield 2 and the printed wiring board 6 is 50 m.
When it is fixed to m, it is found that there is a positive correlation shown in FIG. 10, and as C becomes longer, the standard deviation (σ) becomes larger. Therefore, C is preferably 30 mm or less, more preferably 10 mm or less. .

The electrically insulating shield 2 and the printed wiring board 6
The relationship between the distance G and the standard deviation (σ) has a positive correlation shown in FIG. 11 when the distance C between the inner wall 3 of the plating bath and the printed wiring board 6 is fixed to 30 mm. Indeed, since the standard deviation (σ) is large, G is 50 m
m, more preferably between 5 and 10 mm.

The vertical height L of the electrically insulating shield 2
And the standard deviation (σ) is as shown in FIG. 12. When the height L is equal to or smaller than H / 2, the standard deviation (σ) increases linearly. In this embodiment, L is set at 2H / 3. However, the height L is preferably as high as possible to prevent current from flowing around, and is preferably H / 2 or more.

In the horizontal transfer electroplating apparatus shown in FIG.
When plating was actually performed with C at 5 mm, G at 5 mm, and L at 2H / 3, a printed wiring board having an ideal uniform film thickness as shown in FIG. 9 was obtained.

[0018]

According to the present invention, a plating process having a uniform film thickness can be performed even by a plating apparatus of a system for horizontally transporting a printed wiring board by using an electrically insulating shield. By adjusting the distance between the printed wiring board and the inner wall of the plating bath or the electrically insulating shield, and the height of the electrically insulating shield, plating with a more uniform film thickness can be performed. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a horizontal transport electroplating apparatus showing an embodiment of the present invention.

FIG. 2 shows an enlarged view of a plating tank part of FIG.

FIG. 3 is a plan view of the horizontal transport electroplating apparatus shown in FIG.

FIG. 4 is a perspective view of a vertical transport type electroplating apparatus showing a conventional example.

FIG. 5 is a plan view of a horizontal transport electroplating apparatus showing a conventional example.

FIG. 6 is a cross-sectional view of a horizontal transport electroplating apparatus showing a conventional example.

FIG. 7 is a cross-sectional view of a printed wiring board plated by the horizontal transport type plating apparatus shown in FIG. 5;

FIG. 8 is a cross-sectional view of a printed wiring board plated with the horizontal transport type plating apparatus shown in FIG. 6;

9 is a cross-sectional view of a printed wiring board plated with the horizontal transport electroplating apparatus of the present invention shown in FIG.

FIG. 10 is a graph showing the standard deviation of the plating film thickness when the distance between the inner wall of the plating bath and the printed wiring board is changed.

FIG. 11 is a graph showing a standard deviation of a plating film thickness when a distance between an electrically insulating shield and a printed wiring board is changed.

FIG. 12 is a graph showing a standard deviation of a plating film thickness when a vertical height of an electrically insulating shield is changed.

[Explanation of symbols]

1. Anode 2. Shield 3. 3. Plating tank inner wall Plating tank 5. Grasping body 6. Printed wiring board 7. Drive motor 8. Pulley
9. Plating solution 10. Transport drive unit 11. Jig 12.
Transfer robot 13. Pump 14. Rectifier 15. Voltage / current regulator 16. Plating film

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masami Nakajima 1425 Ogawa Oji, Shimodate City, Ibaraki Prefecture Within Hitachi Chemical Techno Plant Co., Ltd. Inside

Claims (4)

[Claims] An apparatus for performing electroplating while holding a printed wiring board horizontally in a plating bath, wherein a gripper for holding one side of the printed wiring board and a printed wiring board when the printed wiring board is installed And a pair of upper and lower anodes that are equally spaced from each other, and an electrically insulating shield that is erected at a predetermined distance from a side of the printed wiring board opposite to a side held by the gripper. A horizontal transport electroplating apparatus characterized by the following. 2. The horizontal transfer electric device according to claim 1, wherein a distance between a side held by a gripping body of the printed wiring board and an inner wall of the processing tank is 30 mm or less when performing electroplating. Plating equipment. 3. The horizontal transport electroplating apparatus according to claim 1, wherein the distance between the electrically insulating shield and the end of the printed wiring board is 50 mm or less. 4. The vertical length of the electrically insulating shield is:
The horizontal transport electroplating apparatus according to claim 1, wherein the distance is at least に of a distance between anodes provided above and below the processing tank. 5.