KR100582129B1 - Plating device - Google Patents

Abstract

It is desired to form a plurality of combination plating films in succession in one conveyance rail. In order to meet this demand, a simple solder plating apparatus is provided.

This plating apparatus installs several plating bath in the lower part of a conveyance rail, and installs a plating liquid storage bath in this plating bath. The plating film formed on the conductive member 21 can be selected by moving the plating solution in the plating bath and the plating liquid storage bath. As a result, a plurality of combination plating films can be formed on the conductive member 21 continuously in one conveyance rail.

Transverse Pusher, Transfer Rail, Pre-Dip Bath, Plating Bath, Water Washing Bath, Plating Solution Aisle Pipe, Plating Bath

Description

Plating Equipment {PLATING DEVICE}

BRIEF DESCRIPTION OF THE DRAWINGS The figure explaining the plating line used for the plating apparatus of this invention.

2 is a view for explaining a plating line used in the plating apparatus of the present invention.

3 is a view for explaining a semiconductor chip which performs the present invention and conventional plating.

Fig. 4 is a view for explaining a cross section viewed from the A-A direction of the semiconductor lead frame shown in Fig. 3, which is made of the present invention and the conventional two-layer plating film.

Fig. 5 is a view for explaining the layout of the present invention and the whole automatic plating apparatus.

Fig. 6 is a view for explaining a cross section seen from the B-B direction of the chemical etching bath of the entirety of the present invention and the conventional automatic plating apparatus shown in Fig. 5;

<Explanation of symbols for the main parts of the drawings>

21: conductive member

22: first plating film

23: second plating film

31: alkali electrolytic cleaning bath

32, 34, 36, 38, 40, 277, 377: tub for water washing

33: chemical etching bath

35: acid activated bath

37: solder plating apparatus

39: neutralization bath

41: hot water wash tub

42: drying device

271, 331, 371: Lateral feed pusher

272, 332, 372: conveying rail

273, 373: Free Deep Tub

274, 374: first plating bath

275, 375: second plating bath

276, 376: third plating bath

278, 378: plating liquid passage pipe

279, 379: first plating liquid storage bath

280, 380: second plating liquid storage bath

381: 3rd plating liquid storage bath

333: Suspension hook

334: plating auxiliary rack

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating apparatus, and relates to a plating apparatus in which a plating bath and a plating liquid storage tub corresponding to the bath are connected by a pipe, and the plating solution can be moved. And as a plating liquid moves between both bathtubs, it is related with the plating apparatus which can form the single layer or at least 2 layer or more of the plating film of the metal material of multiple combination in one conveyance rail.

The lead material which coat | covered the surface of the electrically conductive member, such as a Cu single member, Cu alloy, or Fe-Ni alloy, with the plating layer of Sn single member or Sn alloy, has the outstanding electroconductivity and mechanical strength which the Cu single member or Cu alloy has. In addition, the lead material is a high-performance conductor that combines the corrosion resistance and good solderability of the Sn single member or the Sn alloy. Therefore, they are widely used in the field of electric and electronic devices such as various terminals, connectors, and leads, and the field of power cables.

In addition, when mounting a semiconductor chip on a circuit board, it is performed to improve the solderability of an outer lead part by carrying out the fusion plating or electroplating which used Sn alloy by the outer lead part of a semiconductor chip. Representative examples of such Sn alloys are solder (Sn-Pb alloys), and because they have good solderability, corrosion resistance, and the like, they are widely used for industrial plating of electrical and electronic industrial parts such as connectors and lead frames.

FIG. 4 is a cross-sectional view showing the basic configuration of an AA cross-section lead material in the semiconductor lead frame shown in FIG. For example, the conductive member 21 is composed of a Cu-based alloy containing Cu and Cu as a main component or a Fe-Ni-based alloy containing Fe-Ni as a main component. And the plating film of 2 layers which is another metal material is given to the surface of these electrically conductive members 21. As shown in FIG. For example, the first plating film 22 of Sn and the second plating film 23 of Sn-Bi are formed in this order. Here, when the thickness of the first plating film 22 is t ₁ and the thickness of the second plating film 3 is t ₂ , t ₁ is about 3 to 15 μm, t ₂ is about 1 to 5 μm, When t ₂ / t ₁ is set at about 0.1 to 0.5, it has good properties in terms of cost, solderability and heat resistance, and also in terms of solder joint strength and welding strength of the welded portion with aluminum wires. It is known that it is suitable because a performance improvement can be obtained.

5 is a layout of the entire automatic plating apparatus. First, in the alkaline electrolytic cleaning bath 31, organic contaminants such as oils and fats that impair adhesion and solderability of the solder plating film on the surface of the conductive member 21 are removed. Next, after being washed in the water washing bath 32, the chemical etching bath 33 is subjected to a chemical etching process (basically, a process using an oxidation reduction reaction), and then to the presence of grain boundaries or inclusions. As a result, the surface of the conductive member 21 which becomes a nonuniform surface is made uniform.

Next, the oxide film adhered to the water washing bath 34 is removed in the acid activating bath 35 after being washed in the water washing bath 34. Next, after wash | cleaning in the water washing tub 36, plating is performed in the solder plating apparatus 37. FIG. Since the solder plating solution is strongly acidic, the surface after plating is acidic. On such surfaces, the coating discolors with time, and the solderability deteriorates. Therefore, in the water washing bath 38 and the neutralization bath 39, the acid remaining on the plating surface is neutralized to remove the adsorbed organic matter. Thereafter, the water washing tub 40 and the hot water washing tub 41 are washed, and in the drying apparatus 42, the plated conductive member 21 is dried.

FIG. 6 is a cross-sectional view in the B-B direction of the chemical etching bath 33 in the overall plating apparatus shown in FIG.

The operation in the chemical etching bath 33 is as described above. Here, the structure in this plating apparatus is demonstrated. In this plating apparatus, both the lateral transfer type pusher 331 and the conveyance rail 332 are movable in an up-down direction. And the upper limit position and the lower limit position of these movable ranges are determined, and it moves repeatedly between them. The hanging hook 333 is hooked to the conveyance rail 332 at suitable intervals according to the work purpose. It is usually the distance between the centers of adjacent baths. And the plating auxiliary rack 334 which suspends the electrically-conductive member 21 to be plated is caught by this suspension hook 333, and is attached to this plating apparatus. Next, the transverse pusher 331 will be described. The distance between the transverse pushers 331 is basically equal to the distance between the centers of adjacent baths. And this lateral feed pusher 331 is provided in one arm, and it returns to that much when the suspension hook 333 is conveyed by one span in a working direction. And this lateral feed pusher 331 is conveyed 1 span at the upper limit position, and it returns to that much from the lower limit position. In addition, although the conveyance rail 332 moves to an up-down direction, it does not move to an advancing direction. By the repetition of this work, this plating apparatus is functioning.

In the above plating apparatus, there was one preplating treatment line and one solder plating line. For example, when the plating film of Sn is formed in the 1st plating film 22 in the conductive member 21, and the Sn-Bi plating film is formed in the 2nd plating film 23, and the 1st plating in the conductive member 21 is carried out. The plating film of Sn may be formed in the film 22 and the plating film of Sn-Ag may be formed in the 2nd plating film 23 in some cases. In this case, the first plating film may use the same Sn plating solution, but the second plating film uses a different plating solution. Therefore, after finishing forming the former plating film in the electrically-conductive member 21, after stopping the 1-degree plating apparatus, replacing the plating liquid in the bathtub with the latter plating liquid, the plating film was formed in the next electrically-conductive member 21. .

As described above, in this solder plating apparatus, there was one preplating treatment line and one solder plating line. For this reason, when a plurality of combinations of plating films are formed on the conductive member 21, there is a problem that the operation cannot be performed continuously when the combination of plating films is replaced. In other words, in this plating apparatus, the conductive member 21 was immersed in the prepared plating solution in order to form a plating film of the same plating film combination continuously. However, according to the use of the electrically conductive member 21 to be plated, plural combination plating films could not be continuously formed in the electrically conductive member 21. That is, there was a problem that a large amount of time and effort was spent on replacing the plating liquid with respect to the solder plating line.

In addition, in addition to the above, much effort has been put into managing the solder plating line. For example, after using the plating liquid which is one plating bath, another plating liquid with a different plating liquid structure may be used. At this time, if the former plating liquid is not removed reliably, the liquid composition of the latter plating liquid is replaced. In addition, if the plating liquid composition to be used differs, the anode used in the plating bath will also need to be replaced differently. That is, there has been a problem that a lot of effort is put into the maintenance surface such as plating solution management or plating bath management.

In order to achieve the above object, in the present invention, the plating line has a plurality of plating baths in the lower portion of the conveying rail. In addition, a plating liquid storage bath is provided corresponding to the plating bath to provide a function of moving the plating liquid between both bathtubs. Alternatively, a plurality of plating baths and plating solution storage baths are provided at the bottom of the conveyance rail to provide a function of moving the plating solution between both baths. Thereby, it is characterized by being able to form a plural combination of single layer or two or more plating films continuously to the conductive member 21 in one conveyance rail.

1 is a layout briefly showing the function of a solder plating line for carrying out the plating apparatus of the present invention. In this solder plating line, the pre-dip bath 273, the first plating bath 274, the second plating bath 275, the third plating bath 276, and the water washing bath 277 are lower than the conveying rail 272. Is installed on. Then, the plated film is formed on the conductive member 21 (refer to FIG. 4) by the lateral transfer type fuser 271 by one pitch, and the bath is used as in the prior art.

According to the first aspect of the present invention, the plating liquid storage bath is provided as necessary in correspondence with the plating bath. For example, as shown in FIG. 1, the first plating bath 274 is not provided in the first plating bath 274, and the first plating solution storage bath 279 for the second plating bath 275 is used. Second plating liquid storage baths 280 for 276 are respectively provided. In this case, in order to utilize the work space efficiently, a plating liquid storage bath was provided in the lower part of the plating bath so that a plating liquid could be accommodated for a short time at the time of storing a plating liquid. As a result, in this solder plating line, a plurality of combination plating films can be formed in succession to the conductive member 21 in one conveyance rail depending on the intended use.

2 is a layout briefly showing the function of the solder plating line for carrying out the plating apparatus of the present invention, similarly to FIG. In this solder plating line, the pre-dip bath 373, the first plating bath 374, the second plating bath 375, the third plating bath 376, and the water washing bath 377 are formed of the transfer line 372. It is installed at the bottom. Then, the pitches are transferred one by one by the lateral transfer pusher 371, and a plating film is formed on the conductive member 21 by using these bathtubs.

In the second embodiment, the plating liquid storage bath is provided for all the plating baths. For example, as shown in FIG. 2, the first plating liquid storage bath 379 for the first plating bath 374 is used, and the second plating liquid storage bath 380 for the second plating bath 375 is formed. 3rd plating liquid storage baths 381 for the 3 plating baths 376 are provided, respectively. Also in this case, the plating liquid storage bath was provided in the lower part of the plating bath similarly to the said 1st aspect. Thereby, in this solder plating line, it is characterized by being able to form a plurality of combination plating films in succession to the conductive member 21 which can be plated by one conveyance rail according to a use.

Specifically, the conveyance structure of this solder plating line is the same as that of FIG. 6 mentioned above. For example, in the solder plating line of FIG. 1, a plating solution of Sn can be put in the first plating bath 274, a plating solution of Sn-Bi can be put in the second plating bath 275, and a third plating bath is placed. In 276, a plating solution of Sn-Ag can be put. Then, the plating bath required for this plating bath is selected according to the use purpose of the plated conductive member 21, and the plating liquid of the plating bath, which is not necessary, moves to the plating liquid storage bath. In this embodiment, however, the plating liquid can always be put in the first plating bath 274 containing the plating liquid of Sn, and the conductive member 21 is immersed in the plating liquid of Sn. As a result, a single layer plating film of Sn is formed on the conductive member 21, or a plating film of Sn-Bi or Sn-Ag is formed on the second layer by Sn. In addition, since the structure of a lead material is the same as that of FIG. 4, the code | symbol was common.

First, the case where only the 1st plating film 22 of Sn single | mono layer is formed in the electrically-conductive member 21 is demonstrated. Here, the plating liquid of Sn always enters the 1st plating bath 274 into which the plating liquid of Sn was put, and the plating film of Sn is formed in the electrically-conductive member 21. FIG. First, the conductive member 21 processed in the pre-plating treatment line is removed from the surface of the hydroxyl film in the pre-dip bath 273, and the plating solution of Sn in the first plating bath 274 is removed. Immerse. In the meantime, since the plating film is not formed on the conductive member 21 in the second plating bath 275 and the third plating bath 276, the plating liquid in the bath is the first plating liquid storage bath 279 and the second plating liquid storage bath. Go to 280. Although the conductive member 21 in which the Sn plating film was formed in the 1st plating bath 274 is conveyed to the 2nd plating bath 275 and the 3rd plating bath 276, since the plating solution does not enter in these plating baths, Not formed. Next, the surface of the electrically conductive member 21 in which the plating film was formed in the water washing tub 277 is cleaned. As a result, a single layer plating film of Sn is formed on the conductive member 21.

Second, the case where two layers of the first plating film 22 and the second plating film 23 are formed on the conductive member 21 is described. The process of forming a plating film in the conductive member 21 is the same as the above-mentioned content. First, since a plating solution of Sn is always contained in the first plating bath 274, the first plating film 22 of Sn is formed in the conductive member 21. And the plating bath which forms the 2nd plating film 23 is selected according to the use use of the electrically conductive member 21. FIG. Here, when forming the Sn-Bi 2nd plating film 23 initially, the Sn-Ag plating liquid of the 3rd plating bath 276 is moved to the 2nd plating liquid storage bath 280. FIG. Next, in the case where a second plating film of Sn-Ag is formed, the plating solution of Sn-Bi of the second plating bath 275 is moved to the first plating solution storage bath 279, and the third plating bath 276 is moved to the third plating bath 276. The plating liquid of Sn-Ag is returned from the second plating liquid storage bath 280. As a result, two layers of a plating film of Sn and Sn-Bi or Sn and Sn-Ag are formed in the conductive member 21.

In the plating apparatus of FIG. 1, the metal material of the plating liquid of the first plating bath 274 is Sn, the metal material of the plating liquid of the second plating bath 275 is Sn-Bi, and the third plating bath 276. The metal material of the plating liquid is Sn-Ag. And since the solution except those metal and the solvent which melt | dissolves them is the same liquid structure, a plating film can be formed continuously in the electrically-conductive member 21. FIG. However, in some cases, a plating film is formed on the conductive member 21 with a plating liquid having a different liquid composition. At this time, a plating bath in which pure water is placed between plating baths with different plating solution configurations is prepared and the surface of the plated conductive member 21 is cleaned to prevent mixing of the plating solutions with different liquid compositions. And when this pure water is not needed, it puts in a plating liquid storage bath. Thereby, a plurality of combination plating films can be formed in the conductive member 21 continuously in one conveyance rail regardless of the liquid composition of a plating liquid.

Specifically speaking about the second aspect, the plating method of the solder plating line is the same as the first aspect described above. For example, in the solder plating line of Fig. 2, a plating solution of Sn can be put in the first plating bath 374, and Sn: Bi = 98 (weight%): 2 (weight%) in the second plating bath 375. ), And a plating solution of Sn: Bi = 43 (% by weight): 57 (% by weight) may be added to the third plating bath 376. Then, the plating bath required for this plating bath is selected according to the use purpose of the plated conductive member 21, and the plating liquid of the plating bath, which is not necessary, moves to the plating liquid storage bath. As a result, a plating film of Sn or Sn: Bi = 98 (wt%): 2 (wt%) single layer is formed on the conductive member 21, or the first layer is Sn: Bi = 43 (wt%) ): 57 (% by weight) of two layers of plating films are formed, or the first layer is Sn: Bi = 98 (% by weight): 2 (% by weight), and the second layer is Sn: Bi = 43 (% by weight): 57 Two layers (weight%) of a plating film or the like may be formed.

In this second aspect, a plating solution of Sn: Bi = 98 (wt%): 2 (wt%) can be used to form the first plating film 22 on the conductive member 21. At this time, by including Bi in the plating solution about several percent, whiskers (needle crystals) are remarkably suppressed in the first plating film 22.

Therefore, in the present invention, a plating bath in which a plurality of plating liquids with different plating liquid constitutions can be put, and a plating liquid storage bath are provided as necessary or as a whole in the plating bath. And both baths of a plating liquid can be moved according to the use use of the electrically-conductive member 21. FIG. As a result, multiple combination plating films can be formed continuously in one conveyance rail.

That is, a plurality of combination plating films can be formed on the conductive member 21 in one conveyance rail in succession. This eliminates the need to temporarily stop the plating apparatus in accordance with the combination of the plating films to replace the plating liquid in the bath. As a result, the work time can be significantly shortened and the effort of replacing the plating liquid can be saved. In addition, when the plating liquids are replaced in the same bath, the plating liquids are not mixed with each other, and the effort in the management of the plating liquids and the maintenance of the plating bath, the plating equipment, etc. can be greatly reduced.

In addition, a plurality of combination plating films can be formed continuously in one conveyance rail. For example, in the first plating bath, the plating liquid is moved to the first plating liquid storage bath, and the plating film is formed in the second and third plating baths. In the first and second plating baths, the plating solution is used as the first and second plating solutions. There exists a method of moving to a storage bath, and forming a single layer plating film only in a 3rd plating bath. In addition, a thick plating film can be formed on the conductive member 21 by placing a plating solution of the same composition into an adjacent plating bath.

In any case, by moving the plating liquid of this invention between both bathtubs as mentioned above, it is possible to form the plating film of multiple combination continuously in one conveyance rail.

As described above, the case of solder plating has been described as an example, but the plating apparatus can be used without being limited to solder plating. For example, Sn plating, Cu plating, Ni plating, etc. are mentioned. Also in these cases, the plating device of a plurality of combinations can be formed in the conductive member 21 continuously in one conveyance rail using this plating apparatus.

As apparent from the above description, the following effects can be obtained in the plating apparatus of the present invention.

This plating apparatus has a function of moving the plating liquid between both baths in a solder plating line, so that a single layer or a plurality of combination plating films can be continuously formed in one conveyance rail. Therefore, the plating liquid is not replaced every time the plating film formed on the conductive member is replaced, so that the plating apparatus is not temporarily suspended. As a result, since a plurality of combinations of plating films can be formed on the conductive member continuously in one conveyance rail, the working time can be greatly reduced, and the effort for replacing the plating liquid can be saved. In addition, when the plating liquids are replaced in the same bath, the plating liquids are not mixed with each other, and the effort in the management of the plating liquids and the maintenance of the plating bath and the plating equipment can be greatly reduced.

Claims (6)

In a plating apparatus having a pre-plating treatment line and a plating line, The plating line has a plurality of plating baths, and a plating liquid storage bath is provided in the desired plating bath. In a plating apparatus having a pre-plating treatment line and a plating line, The plating line has a plurality of plating baths, and a plating liquid storage bath is provided in each of the desired plating baths. The plating apparatus according to claim 1 or 2, wherein a plating film is formed on a conductive member by the plating bath of the plating line. The plating apparatus according to claim 1 or 2, wherein the plating liquid storage bath is provided at a position lower than the plating bath. The plating apparatus according to claim 1 or 2, wherein the plating bath is connected by the plating liquid storage bath and a pipe to move the plating solution through the pipe. The plating bath according to claim 1 or 2, wherein, in the plating bath in which the conductive member is not immersed, the plating liquid is moved to a corresponding plating liquid storage bath so that the conductive member is not immersed in the plating liquid. A plating apparatus comprising a plurality of plating films formed on the conductive member.

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