JPH0754190A - Partial plaing device - Google Patents

Abstract

PURPOSE:To shorten the time for plating and unify the plating thicknesses by using, as an anode, a metallic plate provided with ejection holes as a nozzle at the time of covering an object to be plated with a mask and subjecting the object to partial plating by ejecting the plating liquid out of the nozzle. CONSTITUTION:The plating liquid in a tank 26 is forcibly fed into a plating liquid supply receptor 18 and the plating liquid is ejected out of the nozzle 36. The specified parts of the object 14 which is to be plated and is enclosed by a mask 12 are thereby partially plated. The nozzle 36 described above is formed of the metallic plate and is provided with the ejection holes 38 consisting of plural through-holes having the same shape. The metallic plate is made of a stainless steel and is used as the anode.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a partial plating apparatus.

[0002]

2. Description of the Related Art In a lead frame for a semiconductor device, a plating film for fixing a semiconductor device and a wire bonding film, for example, a silver plating film, are formed on the element mounting portion (stage) and the tips of the inner leads, respectively. This plating film is applied by a partial plating apparatus called jet plating. FIG. 6 shows an example of the partial plating apparatus. Reference numeral 10 is a sparger, which has a closed box shape. Reference numeral 12 denotes the mask, and a portion corresponding to a plating region of the lead frame 14 as an object to be plated is opened, and the lead frame 14 is pinched with the contact plate 16.
A plating solution supply container 18 is arranged in the sparger 10, and a nozzle plate 20 is arranged on the front side thereof. Reference numeral 22 denotes a baffle plate that is disposed across the plating solution supply container 18 and has a through hole 24 that allows the plating solution to flow back and forth. The plating solution is introduced from the tank 26 into the plating solution supply container 18 by the pump 28, is further ejected from the nozzle 30 provided in the nozzle plate 20, and is ejected from the opening of the mask 12 to a predetermined portion of the lead frame 14. Reference numeral 32 is a platinum wire serving as an anode, which is stretched near the tip of the nozzle 30. As shown in FIG. 7, the nozzle plate 20 is formed by fixing a vinyl chloride tubular body to a through hole provided in a vinyl chloride plate body and forming the nozzle 30. The nozzle 30 is composed of a plurality of units. A predetermined number of lead frames 14 are connected to each unit lead frame. The platinum wire 32 is supported and stretched by a grooved support frame 34.

[0003]

The above-mentioned conventional partial plating apparatus has the following problems. In other words, recently, the lead frame is formed in a fine pattern due to the high density of semiconductor elements, and in particular, a plurality of power supply leads and ground leads are set in other positions not in the same row as the inner lead tip in addition to the signal lead. As a result, the shape and structure have become complicated, and instead of the conventional rectangular plating area, a complicatedly complicated plating area has appeared. When spraying the plating solution onto the plating area having such a complicated shape by the conventional nozzle 30 projecting in a cylindrical shape as described above, the plating solution cannot be sprayed uniformly over the entire plating area, resulting in a plating film having a uniform thickness. The problem is that it is difficult to get. It is considered that the arrangement position of the nozzle 30 may be changed corresponding to a complicated plating region, but the nozzle 3 may be formed due to the relationship with the platinum wire 32 or the like, or the cylindrical shape.
There is also a circumstance that it is difficult to arrange 0 freely. The platinum wire 32 is also expensive.

Therefore, the present invention has been made to solve the above problems, and an object of the present invention is to form a uniform plating film sufficiently corresponding to a complicated plating region and at a low cost. It is to provide a partial plating apparatus that can be formed into a.

[0005]

The present invention has the following constitution in order to achieve the above object. That is, in a partial plating apparatus that covers an object to be plated with a mask and jets a plating solution from a nozzle to an opening of the mask to perform partial plating on a plating region of the object to be plated, the nozzle is to be plated. It is characterized in that a metal plate provided with ejection holes for ejecting a plating solution in a plating region of an object is used, and the metal plate is used as an anode. It is preferable that the ejection holes are formed as a plurality of through holes having the same shape. Further, it is preferable that the metal plate is made of stainless steel.

[0006]

The operation of the present invention will be described with reference to FIGS. The pump 28 pumps up the plating solution in the tank 26 and pumps the plating solution into the plating solution supply container 18 to eject the plating solution from the ejection holes 38 to the plating area of the lead frame 14 surrounded by the mask 12. 14
Partial plating can be applied to a predetermined part of the. In this case, since the nozzle plate 36, which is a metal plate, itself serves as an anode, a large current density can be obtained and the plating time can be shortened. Further, as shown in FIG. 2, the nozzle plate 36 is provided with an ejection hole 38, and the ejection hole 3 is formed.
No. 8 can be freely arranged at any position of the nozzle plate 36 corresponding to the plating area, and the plating solution can be uniformly ejected even in a complicated plating area, and a plating film having a uniform thickness can be obtained. By making the ejection holes 38 have the same shape, the flow velocity of the ejected plating solution can be made the same, which also makes the plating thickness uniform. In addition, the nozzle plate 3
By forming 6 with a stainless plate, it can be formed at low cost.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. In FIG. 1, 10 is a sparger, 12 is a mask thereof, 14 is a lead frame as an example of an object to be plated, 16 is a contact plate, 18 is a plating solution supply container, and 22 is a transverse distribution in the plating solution supply container 18. A baffle plate is provided, 24 is its through hole, 26 is a tank of plating solution,
Reference numeral 28 is a pump, which is basically constructed in the same manner as the conventional partial plating apparatus. Reference numeral 36 denotes a nozzle plate, which is a metal plate mounted on the front surface of the plating solution supply container 18, and is preferably formed of a stainless plate. The nozzle plate 36 also serves as an anode. As shown in FIG. 2, the nozzle plate 36 has a lead frame 14
A plurality of ejection holes 38 having the same shape are opened corresponding to the plating area of each unit lead frame. The nozzle plate 36 shown in FIG. 2 is for a quad-type lead frame, and the four ejection holes 38 in the central portion are mainly on the stage, and the twelve ejection holes 38 on the periphery surround the stage, and the tip portion of the inner lead. It is arranged to correspond to.

Each of the ejection holes 38 is preferably formed as a through hole having the same shape so that the plating solution pumped into the plating solution supply container 18 is ejected at substantially the same flow rate, and in the illustrated example, it is circular. Is formed in. Further, it is preferable to chamfer the edge of the ejection hole 38 on the mask 12 side as necessary as shown in FIG. 3 and adjust the ejection angle of the plating solution by the taper angle of the chamfered portion 38a. is there.
Reference numeral 40 denotes an auxiliary electrode, which is screwed into a screw hole provided in the nozzle plate 36 and provided at an arbitrary position, and is projected toward the inner lead 14 as shown in FIG. By forming the auxiliary electrode so as to correspond to, for example, a corner portion of a plating region where the plating solution is hard to rotate, the current density of the portion can be increased and the plating area can be improved. Reference numeral 42 is a hole for mounting the nozzle plate 36, and the nozzle plate 36 is liquid-tightly mounted on the tip of the plating solution supply container 18 by a bolt (not shown). FIG. 5 shows another embodiment. In this embodiment, the ejection hole 3
Only two 8 are formed for each unit lead frame, and are formed in the same long hole. As described above, the shape and the arrangement of the ejection holes 38 are not particularly limited, and are appropriately selected according to the shape of the plated region of the lead frame 14.

With the above-described structure, the pump 28 pumps up the plating solution in the tank 26 and pumps it into the plating solution supply container 18, and the plating solution is surrounded by the mask 12 from the ejection holes 38. It is possible to carry out partial plating on a predetermined portion of the lead frame 14 by jetting it onto the plating region of the lead frame 14. In this case, since the nozzle plate 36, which is a metal plate, itself serves as an anode, a large current density can be obtained and the plating time can be shortened. The ejection holes 38 can be freely arranged at any positions of the nozzle plate 36 corresponding to the plating area, and the plating solution can be evenly ejected even in a complicated plating area, and a plating film having a uniform thickness can be obtained. . By making the ejection holes 38 have the same shape, the flow velocity of the ejected plating solution can be made the same, which also makes the plating thickness uniform. In particular, by providing the auxiliary electrode 40, it is possible to cope with a more complicated shape of the plating region. Further, by forming the nozzle plate 36 with a stainless plate, it can be formed at low cost.

Although the present invention has been variously described with reference to the preferred embodiments, the present invention is not limited to these embodiments, and many modifications can be made without departing from the spirit of the invention. Of course.

[0011]

According to the partial plating apparatus of the present invention,
With a simple structure, the plating time can be shortened, the plating thickness can be made uniform even in a complicated plating region, and the structure can be inexpensively produced.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing an example of a partial plating apparatus.

FIG. 2 is a front view showing an example of a nozzle plate.

FIG. 3 shows a sectional view of a nozzle hole.

FIG. 4 shows a side view of a nozzle plate.

FIG. 5 is a front view showing another embodiment of the nozzle plate.

FIG. 6 is a sectional view of a conventional partial plating apparatus.

FIG. 7 is a front view of a conventional nozzle plate.

[Explanation of symbols]

 10 sparger 12 mask 14 lead frame 16 contact plate 18 plating solution supply container 36 nozzle plate 38 ejection hole

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[Procedure amendment]

[Submission date] January 7, 1994

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[Figure 7]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norio Wakabayashi 711, Kurita, Nagata, Nagano, Nagano Prefecture Shinko Electric Industry Co., Ltd. (72) Nobuyuki Kurashima, 711, Shinoda, Kurita, Nagano, Nagano Electric Industry Co., Ltd.

Claims (3)

[Claims] 1. A partial plating apparatus which covers an object to be plated with a mask and jets a plating solution from a nozzle to an opening of the mask to partially plate a plating region of the object to be plated corresponding to the opening. A partial plating apparatus using a metal plate provided with ejection holes for ejecting a plating solution in a plating region of an object to be plated, and using the metal plate as an anode. 2. The partial plating apparatus according to claim 1, wherein the ejection holes are a plurality of through holes having the same shape. 3. The partial plating apparatus according to claim 1, wherein the metal plate is made of stainless steel.