JPH07254674A - Plating equipment for lead frame and electrode stripping apparatus therefor - Google Patents

Abstract

PURPOSE:To prevent fluctuation in the thickness of plating and to prevent the plating liquid from being entrained while automating the operation for striping the electrode with high efficiency. CONSTITUTION:When a lead frame 1 is subjected to plating while being carried, a plating liquid 11a is ejected to the rear surface of the lead frame 1 by means of a first pump 15. The plating liquid 11a is also dropped naturally from a liquid storage tank 17 onto the surface of the lead frame 1 thus feeding the plating liquid positively onto the surface of the lead frame 1. Furthermore, an endless cathode wire 14 is provided while penetrating a plating bath and a stripping tank. The cathode wire 14 is disposed oppositely to a plating anode plate 12 in the plating bath and disposed oppositely to a stripping anode plate in the stripping tank.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating device for a lead frame such as an IC lead frame and a peeling device for electrodes used therein.

[0002]

2. Description of the Related Art In general, a lead frame such as an IC lead frame is formed by photo-etching or pressing a thin strip-shaped metal into a shape having a large number of leads. In order to perform various surface treatments (plating, etc.) on the surface of such a lead frame, the lead frames connected in multiples (for example, 3 to 10) are continuously conveyed while being immersed in the treatment liquid. The most common method is to do so. In this case, as the transportation method, a roller transportation method using a roller conveyor, a rack hooking method, a hold / release method using a spring or the like is used.

Here, as the plating applied to the surface of the lead frame, spot plating of silver or the like, plating for pretreatment of this spot plating (for example, copper strike plating or nickel plating), exterior solder plating, etc. There are types.

[0004]

By the way, as described above, when the lead frame surface is plated, especially in exterior solder plating, since the lead frame is already resin-molded, the lead frame is likely to be distorted during transportation. There was a problem. For this reason, conventionally, a method of hooking and transporting the lead frame has been adopted, but in the case of this method, there is a problem that the plating thickness tends to vary, and the required average film thickness cannot be plated. is there.
Further, this hooking method has a problem that the plating solution is taken out of the plating tank.

On the other hand, regarding the cathode contactor used for plating, it is preferable to remove the plating adhering to the cathode contactor and recycle the cathode contactor.
The conventional chemical peeling method has a problem that the peeling speed is slow and the apparatus becomes large. Further, in the fact that the electrolytic stripping method has not been developed yet, a sufficiently satisfactory apparatus for efficiently performing the plating process and the electrode stripping process has not been developed.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a lead frame plating apparatus which does not cause variations in plating thickness and carry-out of plating solution. Is. It is another object of the present invention to provide an electrode peeling device used in a lead frame plating device capable of automatically and efficiently performing a peeling process of an electrode used for plating and reusing the electrode. It is a thing.

[0007]

In order to achieve the above-mentioned object, a lead frame plating apparatus according to the present invention performs plating on the surface of a lead frame while conveying the lead frame while being immersed in a plating solution. In the lead frame plating apparatus, a liquid flow forming means for forming a liquid flow of the plating liquid toward the lead frame is provided.

Here, the liquid flow forming means may be a pump for spraying the plating solution onto the lower surface of the lead frame, and a storage tank for allowing the plating solution to naturally drop onto the upper surface of the lead frame. It is also possible to use a pump that raises the plating solution to the storage tank. In this case, it is preferable to arrange the anode plate for plating along the outer surface of the liquid flow of the plating solution.

The electrode stripping apparatus according to the present invention is an electrode stripping apparatus used in a lead frame plating apparatus for plating the surface of a lead frame while transporting the lead frame while being immersed in a plating solution. An endless electrode wire that is circulated through each of the plating tank and the peeling tank is driven, and the electrode wire is arranged to face the plating anode plate in the plating tank and is peeled in the peeling tank. It is characterized in that it is arranged so as to face the anode plate.

Here, it is preferable that the electrode wire is grounded, and the plating anode plate is connected to a positive terminal and the stripping anode plate is connected to a negative terminal. Further, it is preferable that the electrode wire is arranged so as to come into contact with both the lead frame and a plurality of transport rollers that transport the lead frame in the plating tank. In this case, it is preferable to provide an escape rod for retracting the electrode wire to a position separated from the lead frame between the adjacent transport rollers.

[0011]

In the lead frame plating apparatus according to the present invention, the lead frame is immersed in the plating solution by, for example, a flow of the plating solution sprayed from below or a flow of the plating solution spontaneously dropped from above. The plating solution is surely supplied to the surface of the lead frame transported by. Therefore, the variation in the plating thickness is prevented, the plating having the average film thickness is reliably performed on the lead frame, and the plating solution is prevented from being taken out of the plating tank.

In this case, if the plating anode plate is arranged along the outer surface of the plating solution flow, the plating solution flow is reliably directed to the lead frame side, and the plating solution is supplied to the lead frame surface. Will be more certain.

In the electrode stripping apparatus according to the present invention, when the electrode wire is in the plating bath, the electrode wire is driven by an endless electrode wire which is circulated through the plating bath and the stripping bath. The surface of the lead frame is plated by the wire and the anode plate for plating, and when the electrode wire is in the peeling tank, the plating adhered to the electrode wire is peeled by the electrode wire and the anode plate for peeling. In this way, the adhered plating of the electrode wire is automatically and efficiently peeled off, which can contribute to the reuse of the electrode.

In this case, if a relief rod for retracting the electrode wire to a position separated from the lead frame is provided between the transport rollers adjacent to each other, the lead frame portion in contact with the electrode wire will have a trace without plating. Is prevented, and the plating can be surely adhered to the entire surface of the lead frame.

[0015]

EXAMPLES Next, specific examples of the lead frame plating apparatus and the electrode peeling apparatus used therefor according to the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a carrier device used in a lead frame plating apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic view of a main part of the plating apparatus (A in FIG. 1).
Arrow view) is shown. The plating apparatus according to the present embodiment is applied to a plating process for performing exterior solder plating on the lead frame 1 that has been resin-molded 1a and is connected in multiple lines. In the transfer device used in this embodiment, two main support bars 2 and 2 are supported by a support frame (not shown) and are arranged in parallel to each other in the transfer direction. An expansion / contraction screw bar 3 formed by threading in the right and left opposite directions with respect to the central portion is screwed into each of the main support bars 2, and the expansion / contraction screw bar 3 is rotated by a motor (not shown). The distance between them is adjustable. A support plate 4 is attached to each main support bar 2 so as to face each other at predetermined intervals.
In the lower part, a drive gear 5 is pivotally supported, and in the upper part, an upper roller 6 as a pressing roller is pivotally supported.

A roller 7 with a collar is integrally attached to the drive gear 5. The flanged roller 7 is a roller main body 7 a that supports the lower surface of the side edge portion of the lead frame 1.
And a flange portion 7b integrally provided on the drive gear 5 side of the roller body 7a. Here, when the lead frame 1 is conveyed by the roller 7 with the collar, the flange portion 7b comes into contact with the side edge of the lead frame 1 and restricts the movement of the lead frame 1 in the width direction.

As shown in FIG. 3, a common transmission gear 8 is meshed with the two drive gears 5 and 5 forming a pair on the base end side in the carrying direction, and the drive gears 5 adjacent to each other are also engaged. , 5, an intermediate gear 9 is interposed. Here, the intermediate gear 9 is supported by a support plate (not shown) attached to the main support bar 2, and the transmission gear 8 is also supported by a support plate (not shown). In this way, when the transmission gear 8 is rotated by the rotation of the motor 10, all the drive gears 5 of each pair are synchronously rotated in the same direction, whereby the collared rollers 7 are driven by the drive gears 5 as indicated by arrows B. Is rotated in the same direction as.

The upper roller 6 presses the lead frame 1 supported on the roller main body 7a of the flanged roller 7 from above, and is located slightly inside the roller main body 7a of each flanged roller 7. It is arranged so as to be rotationally driven in synchronization with the collared roller 7 by a motor (not shown). The upper roller 6 may be a free roller.

Thus, as shown in FIG. 2, the lead frame 1 to be transported is arranged so as to be positioned below the liquid level L of the plating solution 11a in the plating tank 11, and the legs of the lead frame 1 are placed. The lower surface of the portion 1b is supported on the roller main bodies 7a of the pair of left and right flanged rollers 7 that are synchronously driven, and the upper surface of the foot portion 1b of the lead frame 1 is pressed by the upper roller 6 so that these roller main bodies 7a It is conveyed forward while being sandwiched between the upper rollers 6. At this time, the flange portions 7b provided integrally with the roller body 7a are in contact with both side edges of the lead frame 1 to restrict the movement of the lead frame 1 in the width direction.

Anode plates (anode plates) 12 for plating, which are arranged in a tapered shape toward the lead frame 1 side, are provided above and below the lead frame 1 conveyed as described above. ing. Further, a groove 13 is formed in the roller body 7a of the flanged roller 7 in the circumferential direction, and the cathode 13 has a circular cross section so as to fit in the groove 13 and to contact the foot portion 1b of the lead frame 1. A wire (cathode contact band) 14 is provided.

The plating solution 11a in the plating tank 11 is circulated by the first pump 15 provided at the lower center of the plating tank 11 and flows toward the lower surface of the lead frame 1 (see arrow C in FIG. 2). ) Is formed, and the liquid is pumped up by the second pump 16 and once stored in the liquid storage tank 17, the free-falling liquid flow toward the upper surface of the lead frame 1 via the supply pipe 18 (arrow D in FIG. 2).
) Is formed. These respective liquid streams are directed to the upper and lower surfaces of the lead frame 1 by the plating anode plate 12 which is arranged in a tapered shape toward the lead frame 1 side along the outer surfaces of the liquid streams. As a result, the plating solution 11a is reliably supplied to the surface of the lead frame 1.

As shown in the schematic view of FIG. 4, the cathode wire 14 is arranged endlessly so as to penetrate through the plating bath 11 and a stripping bath 19 provided separately from the plating bath 11. The drive roller 20 is driven to circulate in synchronization with the flanged roller 7 in the transport direction of the lead frame 1. A stripping anode plate 21 is provided in the stripping tank 19 so as to face the cathode wire 14. Here, the cathode wire 14
Is connected to each ground terminal of the plating rectifier 22 and the stripping rectifier 23, the plating anode plate 12 is a positive terminal (for example, +5 V) of the plating rectifier 22, and the stripping anode plate 21 is a negative electrode of the stripping rectifier 23. Terminal (eg -5V)
Respectively connected to. Thus, metal ions are deposited on the lead frame 1 and the cathode wire 14 in the plating tank 11, and the cathode wire 14 is separated in the peeling tank 19.
The metal ions attached to are dissolved. In the peeling tank 19, the liquid in the tank is circulated by a liquid circulation pump (not shown).

The cathode wire 14 also includes, as shown in FIG. 5, adjacent flanged rollers 7,
A relief rod 24 provided between the flanged rollers 7 is used to retract the flanged rollers 7, 7 to a position separated from the lead frame 1. By providing such escape rods 24, it is possible to prevent the traces on the lead frame contacting the cathode wires 14 from being left without plating, and it is possible to reliably deposit plating on the entire surface of the lead frame 1.

In order to prevent the lead frame 1 from being deformed at the time of carrying it in the lead frame 1 carrying device in this embodiment, as shown in FIG. 6, the resin mold 1a of the lead frame 1 being carried is formed. An endless belt 25 is arranged at a lower position (in FIG. 6, only a cross section of the upper portion of the belt 25 is shown), and lift sponges 26 are attached to the belt 25 at predetermined intervals to lift them. Lead frame 1 with sponge 26
It is preferable to support the resin mold 1a. By doing so, the lead frame 1 in the case of forming a liquid flow of the plating solution toward the lead frame 1 in particular
It is possible to reliably prevent the deformation and the like. Note that such an endless belt 25 can be arranged not only below the resin mold 1a but also above it. Further, in order to perform the plating treatment without any trouble, it is preferable that the belt 25 is a perforated or mesh-shaped plastic belt, preferably a urethane molded belt.

In the above description, the lead frame 1
Although the description has been made on the case where the sheets are conveyed in only one row, in the actual processing apparatus, the conveying apparatuses as shown in the drawing are arranged side by side in a plurality of rows in the lateral direction (direction orthogonal to the conveying direction) and The drive gear 5 is driven synchronously so that a plurality of rows of lead frames 1 can be processed simultaneously.

In the carrying apparatus of the present embodiment, when carrying the lead frames 1 having different widths, the expansion / reduction screw bar 3 is rotated by a motor so that the interval between the main support bars 2 and 2 is leaded. It can be adjusted according to the width of the frame 1. Therefore, even if the width of the lead frame 1 is changed, it is possible to prevent the meandering, the jamming, and the like that occur when the lead frame 1 is conveyed, and it is possible to reliably prevent the lead frame 1 from being deformed due to the meandering and the like. it can.

In the present embodiment, the one applied to the exterior solder plating step of the resin-molded lead frame has been described. However, the above-described method for forming the liquid flow of the plating solution to surely perform the plating is It can also be applied to silver spot plating on a frame (bare metal) and pretreatment plating such as copper strike plating and nickel plating leading to this spot plating.

In this embodiment, the cathode wire 14 is arranged so as to fit in the groove 13 of the roller body 7a of the flanged roller 7, but the cathode wire is formed to have a flat cross section. Then, it may be sandwiched between the roller body 7a and the lead frame 1 or between the upper roller 6 and the lead frame 1.

[0030]

As described above, according to the lead frame plating apparatus of the present invention, since the plating solution is reliably supplied to the surface of the lead frame by the liquid flow forming means, variations in plating thickness are prevented. As a result, it is possible to reliably perform plating with an average film thickness, and it is possible to prevent the plating solution from being taken out of the plating tank. In this case, by arranging the plating anode plate along the outer surface of the plating solution flow, the plating solution flow can be reliably directed to the lead frame side, and the plating solution can be supplied to the lead frame surface. It can be performed more reliably.

According to the electrode peeling apparatus of the present invention,
Since the endless electrode wire that is circulated and driven through the plating tank and the stripping tank is provided, the plating adhered to the electrode wire can be stripped automatically and efficiently. Can be used for recycling. In this case, if a relief rod for retracting the electrode wire away from the lead frame is provided between the transport rollers adjacent to each other, it is possible to prevent the lead frame portion in contact with the electrode wire from being left with a trace without plating. Therefore, the plating can be surely adhered to the entire surface of the lead frame.

[Brief description of drawings]

FIG. 1 is a perspective view of a transfer device used in a lead frame plating apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration diagram (a view from an arrow A in FIG. 1) of a main part of the plating apparatus of the present embodiment.

FIG. 3 is an explanatory diagram of a drive mechanism in a lead frame transport device.

FIG. 4 is an explanatory diagram of a power supply system of the plating apparatus of this embodiment.

FIG. 5 is a partial side view of the plating apparatus of this embodiment.

FIG. 6 is a main part configuration diagram showing a modified example of the present embodiment.

[Explanation of symbols]

 1 Lead Frame 7 Roller with Collar (Conveying Roller) 11 Plating Tank 11a Plating Solution 12 Anode Plate for Plating 14 Cathode Wire (Electrode Wire) 15 First Pump 16 Second Pump 17 Liquid Storage Tank 18 Supply Pipe 19 Stripping Tank 21 Stripping Anode plate 22 Rectifier for plating 23 Rectifier for peeling

Claims (8)

[Claims] 1. A liquid flow for forming a liquid flow of the plating solution toward the lead frame in a plating apparatus for a lead frame for plating the surface of the lead frame while being transported while being immersed in the plating solution. An apparatus for plating a lead frame, characterized by comprising forming means. 2. The lead frame plating apparatus according to claim 1, wherein the liquid flow forming means is a pump that sprays the plating solution onto the lower surface of the lead frame. 3. The liquid flow forming means is a liquid storage tank that naturally drops the plating liquid onto the upper surface of the lead frame, and a pump that raises the plating liquid to the liquid storage tank. 2. The lead frame plating apparatus described in 2. 4. The lead frame plating apparatus according to claim 1, wherein the plating anode plate is arranged along an outer surface of the liquid flow of the plating solution. 5. An electrode stripping device for use in a lead frame plating device for plating the surface of a lead frame while transporting the lead frame while being immersed in a plating solution, wherein a plating bath and a stripping bath are respectively provided. An endless electrode wire that penetrates and is driven to circulate is provided, and the electrode wire is arranged to face the plating anode plate in the plating tank and to face the peeling anode plate in the peeling tank. An electrode peeling device. 6. The electrode wire is grounded, and
The electrode stripping device according to claim 5, wherein the plating anode plate is connected to a positive terminal and the stripping anode plate is connected to a negative terminal. 7. The electrode according to claim 5, wherein the electrode wire is arranged so as to be in contact with both the lead frame and a plurality of transport rollers that transport the lead frame in the plating bath. Peeling device. 8. The electrode peeling device according to claim 7, wherein a relief rod for retracting the electrode wire to a position separated from the lead frame is provided between the transport rollers adjacent to each other.