JP2011074416A - Apparatus for displacement plating process of belt-shaped material, and method for displacement plating process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for displacement plating process of a belt-shaped material, which can adequately uniformize components of a plating solution in the vicinity of the material to be treated and is effective in preventing the deformation of a flying lead, when continuously plating the belt-shaped material to be treated by using a reel-to-reel technique, and to provide a method for displacement plating process. <P>SOLUTION: The apparatus for displacement plating process, which displacement-plates the surface of the material to be treated 103 while transporting the belt-shaped material to be treated with the reel-to-reel system, includes: a material transportation means for transporting the material to be treated with the reel-to-reel system; and a current-generating plate transportation means which makes the surfaces of the belt-shaped current-generating plates 110 and 111 oppose to the surfaces to be plated of the material to be treated so as not to come in contact with each other and transports the current-generating plates toward the direction opposite to the transportation direction of the material to be treated. The displacement plating treatment method includes plating the material to be treated while agitating the plating solution by a relative motion between the material to be treated and the current-generating plate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a displacement plating apparatus and a displacement plating treatment method for a strip-shaped workpiece effective for continuously performing displacement plating treatment on a strip-shaped workpiece by a reel-to-reel method.

  For a conventional printed wiring board, a flexible wiring board having a structure in which a polyimide film with copper foil is laminated is proposed, and it becomes possible to form fine wiring from the thinness of the copper foil. Miniaturization can be achieved. Furthermore, since the flexible wiring board is made of a belt-like film, continuous chemical liquid processing by a reel-to-reel method is possible, and production efficiency can be improved unlike conventional single wafer processing.

  An example of the flexible wiring board is a tape BGA board in which a large number of leads are formed by etching a copper foil. The tape BGA substrate mainly has a BGA pad on which a solder ball is mounted and a flying lead for bonding to a semiconductor chip via a gold bump. Such a flexible wiring substrate has, for example, a final surface treatment before mounting. In the replacement plating step, replacement plating of tin, silver, gold, solder, or the like is performed on the BGA pad or flying lead made of metal on the wiring board.

  At the time of the displacement plating, in order to obtain a good plating film by making the components in the liquid uniform in the vicinity of the object to be processed and removing foreign substances in the liquid, generally, liquid agitation and filtering by a circulation pump are performed. Done.

However, stirring may be limited depending on the type of the object to be processed. For example, in the case where the object to be processed is a substrate having a part where a circuit is not supported on an insulating substrate such as a flexible wiring substrate having a narrow pitch and fine wiring flying leads, the object to be processed by a circulation pump is directly applied to the object to be processed. When liquid contact occurs, the problem that the flying lead is deformed occurs.
Therefore, in order to avoid deformation of the flying lead, the plating process is currently performed at a position sufficiently away from the workpiece and under weak agitation.

However, in displacement plating, if stirring is insufficient, flying lead material excessive erosion, which is a problem in the mounting process, occurs. In displacement plating, material erosion is governed by the diffusion effect after the reaction, but when the plating solution is heated, a liquid flow due to convection is generated and a stirring effect due to convection occurs only in the device hole. This is because the difference in the stirring effect between the lead and other pattern portions becomes extremely large, and the flying lead is selectively dissolved and corroded.
Therefore, in the agitation of the displacement plating solution, in order to suppress the material erosion of the flying lead, it is necessary to perform an equivalent chemical treatment between the flying lead in the device hole and the other pattern portion in the flexible wiring board.

  On the other hand, for example, in Patent Document 1, there is a report that a uniform chemical treatment can be achieved by spraying a chemical on a hoop material with a nozzle. The nozzle processing in Patent Document 1 cannot be said to be versatile because it causes wiring breakage of the flying lead on a substrate having a portion where a circuit is not supported on an insulating substrate such as a flying lead.

  From the above, in the displacement plating tank, it is necessary to suppress the deformation of the flying lead under the stirring conditions while achieving uniform plating solution components in the vicinity of the strip-shaped workpiece under appropriate liquid stirring conditions. is there.

Japanese Unexamined Patent Publication No. 6-17290

  The present invention has been invented in view of the problems of the prior art, and in the case of continuously plating a strip-shaped workpiece using a reel-to-reel method, the plating solution in the vicinity of the strip-shaped workpiece is treated. It is an object of the present invention to provide a replacement plating apparatus and a replacement plating method for a strip-shaped workpiece, which can effectively homogenize components and prevent deformation of a flying lead.

The invention of claim 1 for solving the above problem is a displacement plating apparatus for carrying out displacement plating treatment on the surface of the object to be treated in a plating tank while transporting the band-like object to be treated by a reel-to-reel method. Because
A workpiece transport means for transporting the workpiece in a reel-to-reel method;
The surface of the belt-like current plate is opposed to the surface to be processed of the object to be processed at least in the plating tank, but is not brought into contact and is conveyed in a direction opposite to the direction in which the object to be processed is conveyed. Current plate conveying means,
It is the substitution plating processing apparatus of the strip | belt-shaped to-be-processed object characterized by comprising.

According to a second aspect of the present invention, the distance between the band-shaped object to be processed and the band-shaped current plate is such that the object to be processed and the current generated by the conveyance are at least when conveyed in the plating tank. The interval at which the plating solution can be stirred by relative movement with the plate,
The displacement plating apparatus for a strip-like object to be processed according to claim 1.

In the invention of claim 3, there are two belt-shaped current plates, and at least the surface of one current plate is a surface on one side of the belt-shaped workpiece when transported in the plating tank. The surface of the other current plate is arranged so as to face the other surface of the strip-shaped workpiece,
A displacement plating apparatus for a strip-like workpiece according to claim 1 or 2.

The invention of claim 4 is a displacement plating treatment method for carrying out displacement plating treatment in a plating tank on the surface of the treatment object while transporting the belt-like treatment object by a reel-to-reel method,
The object to be processed is conveyed by a reel-to-reel method,
Further, the surface of the belt-shaped current plate is opposed to the surface to be processed of the object to be processed at least in the plating tank, but is not in contact with the direction in which the object to be processed is conveyed. Carry
Performing the plating process while stirring the plating solution in the vicinity of the strip-shaped object by relative movement of the object to be processed and the current plate in the plating tank;
It is the substitution plating processing method of the strip | belt-shaped to-be-processed object characterized by comprising.

  According to the present invention, it is possible to easily achieve good circulation of the plating solution in the vicinity of the surface to be plated of the strip-shaped workpiece, and it is possible to prevent excessive erosion of the base material for displacement plating. In addition, since the current plate controls direct liquid contact with the object to be processed by the circulation pump, deformation of the flying lead can be prevented.

The block diagram which shows typically the structure of an example of the conventional plating apparatus. BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows typically the structure of one Example which concerns on the displacement plating processing apparatus of this invention. Explanatory drawing which shows typically the structure of the strip-shaped to-be-processed object in connection with this invention.

  FIG. 1 shows a part of a conventional plating apparatus for reference. The figure shows an example of an overflow structure among chemical treatment apparatuses in the reel-to-reel method, and shows the treatment area of the washing tank 106 and the plating tank 107, and includes a take-up reel 101 and a take-up reel 102. The plating apparatus is a reel-to-reel system that conveys the flexible wiring substrate 103 to be plated in parallel to the processing tank. The air roll 104 and the liquid roll 105 are used for conveyance.

FIG. 2 is a conceptual diagram of a displacement plating apparatus according to the present invention. For example, strip-shaped current-carrying plate endless transfer rolls 108 and 109 are provided, and current flow is generated on both sides of the flexible wiring board 103 to be plated. The plate A110 and the current plate B111 are arranged. The relative positional relationship between the object to be processed and the current plate is such that the surface to be plated of the object to be processed and the surface of the current plate are opposed to each other, and plating is performed between the object to be processed and the current plate. It is preferable to arrange them at intervals such that the liquid can be sufficiently present. This is because the effect of sufficiently stirring the plating solution existing between the two tends to increase due to the relative movement between the workpiece and the current plate.
For conveying the to-be-plated flexible wiring board 103 and the current plates 110 and 111 in the processing tank, for example, a stepped submerged roll 112 may be used. In the treatment tank, liquid agitation is performed by a liquid circulation pump.

  In this example, two current plates are used. However, if there is only one surface to be plated, at least one current plate may be used. Place on the side of the plating surface. The reason why it is arranged on the side of the surface to be plated is that the plating solution that is well agitated by the relative movement between the object to be processed and the current plate (present between the two) is easily supplied to the surface to be plated.

FIG. 3 shows a to-be-plated flexible wiring board 103 having flying leads 203 and BGA pads 204 formed on a base film 201 made of polyimide used in the present invention.
In general, the material of the current plate is preferably a flexible substrate. In the illustrated example, a polyethylene resin film was used. In general, the size of the current plate is preferably equal to or narrower than the width of the object to be plated. In the example of the figure, an object having a width approximately the same as the object to be processed was used. Moreover, since it is more economical for the current plate to be reusable, it is generally more preferable to use an endless one.

  In order to evaluate plating deposition stability and uniformity of liquid agitation in the vicinity of a workpiece in a device for performing displacement plating treatment on a strip-shaped workpiece by the reel-to-reel method in the present invention, a copper material of a flying lead In order to evaluate the presence or absence of excessive erosion and whether or not the current plate can control the direct liquid contact with the object to be processed by the circulation pump, the presence or absence of deformation of the flying lead was checked.

  The flexible wiring board to be plated was made of a three-layer material in which a copper foil (thickness: 8 μm) was bonded to a polyimide tape (thickness: 38 μm). The details of the plated flexible wiring board used in this example are as shown in FIG. The flying leads had a line width and a pitch of 35 μm.

  First, in the apparatus for performing displacement plating on the strip-shaped workpiece according to the present invention, the inside of the plating tank 107 was filled with pure tin plating solution, and liquid stirring by a circulation pump was started.

  Next, after the processing temperature reaches 70 ° C., the two wake plates A110 and B111 are transported at 1.0 m / min in the same direction and opposite to the direction in which the flexible wiring board 103 is transported. Then, the conveyance speed of the flexible wiring board 103 was set to 0.3 m / mim, and conveyance was started.

  First, plating deposition stability was evaluated when the displacement plating apparatus according to the present invention was used. The evaluation method was evaluated by measuring the plating thickness of the 500 μm-diameter BGA pad 204 in FIG. 3 (n = 10) and calculating the variation of the plating thickness.

  As a result of the evaluation, the average film thickness was 1.03 μm, the standard deviation was 0.05 μm, and a good tin plating film with small variations could be obtained.

Next, by evaluating the degree of copper material erosion of the flying lead, it was verified whether or not the liquid component was uniform in the vicinity of the object to be processed by conveying the current plate.
For comparison, the degree of copper material erosion when using the conventional plating apparatus according to FIG. 1 was also evaluated.

  As a result of the test, the copper material erosion of the flying lead was confirmed in the conventional plating apparatus, but the copper material erosion of the flying lead was not confirmed in the displacement plating apparatus according to the present invention. From this, compared with the conventional plating apparatus, in the plating apparatus concerning this invention, it confirmed that the uniform liquid stirring in the to-be-processed object vicinity was possible by conveyance of a current plate.

  Further, in order to evaluate whether or not the current plate can control the direct liquid contact with the object to be processed by the circulation pump, the presence or absence of deformation of the flying lead after the plating of the object to be processed was confirmed.

  As a result of the test, no deformation of the flying lead was confirmed in the plating apparatus according to the present invention. On the other hand, as a result of performing the same test on the conventional plating apparatus shown in FIG. 1 at the same liquid circulation rate, the deformation of the flying lead was shot.

DESCRIPTION OF SYMBOLS 101 ... Unwinding reel 102 ... Take-up reel 103 ... Plated flexible wiring board 104 ... In-air roll 105 ... Submerged roll 106 ... Washing tank 107 ... Plating tank 108- ..Conveying roll A for current plate
109 ... Conveying roll B for current plate
110 ... Current plate A
111 ... Current plate B
112 ... Stepped submerged roll 201 ... Base film 202 ... Device hole 203 ... Flying lead 204 ... BGA pad 205 ... Sprocket hole

Claims (4)

A substitution plating apparatus for carrying out substitution plating treatment in a plating tank on the surface of the workpiece while transporting a strip-like workpiece by a reel-to-reel method,
An object conveying means for conveying the object to be processed by a reel-to-reel method;
The surface of the belt-shaped current plate is opposed to the surface to be processed of the object to be processed at least in the plating tank, but is not brought into contact and is conveyed in the direction opposite to the direction in which the object to be processed is conveyed. Current plate conveying means,
A displacement plating apparatus for a strip-like object to be processed. The distance between the strip-shaped object to be processed and the belt-shaped current plate is such that at least when transported in the plating tank, the plating solution is caused by relative movement between the object to be processed and the current plate by the transport. Is an interval that can be stirred,
The displacement plating apparatus for a strip-like object to be processed according to claim 1. There are two belt-shaped current plates, and at least when the sheet is transported in the plating tank, the surface of one current plate is opposed to the surface of one side of the belt-shaped object, and the other current flow The surface of the plate is arranged so as to face the other surface of the strip-shaped workpiece,
The displacement plating apparatus for a strip-like object to be processed according to claim 1 or 2. A substitution plating method for carrying out substitution plating treatment in a plating tank on the surface of the workpiece while transporting a strip-like workpiece by a reel-to-reel method,
The object to be processed is conveyed by a reel-to-reel method,
Further, the surface of the belt-shaped current plate is opposed to the surface to be processed of the object to be processed at least in the plating tank, but is not in contact with the direction in which the object to be processed is conveyed. Carry
Performing the plating process while stirring the plating solution in the vicinity of the strip-shaped object by relative movement of the object to be processed and the current plate in the plating tank;
A replacement plating method for a strip-like object to be processed.

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