JPH037143B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an injection plating device used for partially plating precious metals such as gold and silver on IC lead frames.

As a conventional jet plating device of this type, there is one shown in FIGS. 1 and 2, for example. In the figure, numeral 1 is a box called a "spargeer", which is equipped with a mask plate 2 that also serves as a mask body and an upper lid. Then, the IC lead frame 3, which is the object to be plated, is brought into contact with the mask plate 2 by using the forward and backward movement of the press plate 4, and the plating liquid A is applied to the plating liquid injection opening 5 provided in the mask plate 2 as shown in the arrow in the figure. The plating liquid is sprayed from the nozzle 6 in the direction shown, and the plating liquid is sprayed onto the island portion 7 for mounting the semiconductor element of the IC lead frame 3 exposed to the plating liquid injection opening 5 and at the tip of the lead pin portion 8 adjacent thereto. 5
The plating target part 8 whose outermost periphery is divided by
Plating liquid A is applied to a. Note that 9 in the figure is a support pin for supporting the island portion.
Further, the nozzle 6 is provided with an anode 10,
The IC lead frame 3 can be made into a cathode during spray plating.

By the way, these conventional injection plating devices only plate the minimum necessary parts due to the skyrocketing prices of precious metals such as gold and silver, and in order to conserve precious metal resources. There was a request to apply the
As the size of IC lead frames increases and the area of the part to be plated increases accordingly, this demand becomes stronger.

Therefore, in order to bond a semiconductor element to the IC lead frame 3, it is essentially sufficient to plate only the plating target part 8a at the tip of the lead pin part 8, and conventionally, the island part 7 is plated with a precious metal. For example, DIE bonding was performed by forming a gold-silicon eutectic, but this idea was devised based on two points: the island part 7 could be replaced with a conductive adhesive without plating. As shown in Fig. 3, an island mask part 11 corresponding to an island part 7 is integrally provided on a mask plate 2 which also serves as a mask body (for example, Utility Model Application No. 57-48265). . According to this conventional technology, it is possible to prevent the plating liquid A from adhering to the island portion 7, and therefore it is somewhat effective in meeting the demand for saving precious metals. However, in general, the shape of the IC lead frame 3 is not constant, and There are types,
Since the sizes of the island portions 7 are often different, it is necessary to prepare a large number of mask plates 2 on which island mask portions 11 are formed to correspond to all the shapes, and when processing holes in the mask plate 2. , the shape of the supporting part 12 of the island mask part 11 must be selected from various shapes according to the shape of the IC lead frame 3 (for example, the cross-sectional view may be triangular, rhombic, semicircular, etc.), and troublesome processing is required. There were also some problems.

Furthermore, recently there are cases where the island portion 7 and the lead pin portion 8 are not on the same plane (specifically, when the IC lead frame 3 is placed on the mask plate 2, the island portion 7 is slightly moved toward the pressing plate 4 side). (I will be traveling on business). In the conventional example, there was also a problem in that the island portion 7 could not be masked.

The present invention has been made in view of the various problems described above, and in addition to the first mask body having a plating liquid injection opening, a plating liquid is sprayed at the tip of the nozzle, and an island part of the IC lead frame is provided. It is an object of the present invention to solve the above-mentioned conventional problems by providing a spray plating device that is equipped with a corresponding second mask body that is replaceable.

Hereinafter, the details of the present invention will be explained based on the drawings. In the following description, parts common to those of the prior art are denoted by common reference numerals, and redundant description will be omitted.

FIG. 4 and FIG. 5 are diagrams showing an embodiment of the present invention. First, to explain the structure, 20 is a nozzle, and the tip 21 has a plating liquid injection opening 5 provided in the mask plate 2, which is the first mask body.
A second mask body 22 is provided which is brought into contact with the island portion 7 of the IC lead frame 3, and is combined with the mask plate 2.

This second mask body 22 is provided with a sealing material 23 at its tip to improve adhesion to the island portion 7, and has a shape corresponding to the island portion 7 of the IC lead frame 3. Further, this mask body 22 is attached near the tip 21 of the nozzle 20 to a support member 24 inserted through the inside of the nozzle 20, and specifically, as shown in the figure, a recess 26 is provided at the lower end of the body 25. The support member 24 is inserted and fitted into the tip of the support member 24 as a support portion, thereby being attached to the support member 24 so as to be replaceable.

Moreover, according to such a mounting structure, the recess 2
By interposing an appropriate spacer at the bottom of the mask 6, the height position of the second mask body 22 can be easily adjusted.

The support member 24 is fixed to a damper member 27 installed inside the box 1, and the nozzle 2
It passes through 0. Similarly to the damper member 27, the nozzle 20 is fixed to a base plate 28 installed within the box 1, and can be converted into an anode.

In addition, in the illustrated example, the body 25 of the second mask body 22
has a tapered shape, but it is fine if the shape does not interfere with the jetting of the plating liquid A from the nozzle 20.
It is not limited to the illustrated shape.

Next, the effect will be explained.

The plating liquid A injected from the tip 21 of the nozzle 20 rises along the body 25 of the second mask body 22, and enters the plating liquid spraying opening 5 of the mask plate 2 between the mask plate 2 and the second mask body. Touch only the plating target part 8a of the IC lead frame 3 that is not covered by the parts 22 and 22, and apply precious metal plating to that part. That is, since the plating target portion 8a is partitioned at its outermost edge f by the plating liquid injection opening 5 and also from the inner island portion 7 by the second mask body 22, the plating liquid is A does not touch any part other than the part to be plated 8a. After colliding with the plating target part 8a, the plating liquid A is quickly collected into the plating box 1.

FIGS. 6 and 7 are diagrams showing other embodiments.

The nozzle 30 in this embodiment has a tip end surface 31
A plurality of nozzle holes 32 are provided in the peripheral portion, and a screw hole 33 is provided as a “support portion” in the center portion. A screw 34 is provided at the lower end of the body 25 of the second mask body 22 as a "threaded part" to be engaged with the screw hole 33, and as shown in the figure, the nozzle 30 is attached to be replaceable.

In this case, the height position of the second mask body 22 can be freely adjusted by adjusting the amount of screwing.

Note that the other configurations and operations are the same as those in the previous embodiment, so redundant explanations will be omitted.

FIGS. 8 and 9 are diagrams showing modifications of the two embodiments described above.

The nozzle 40 in this modification has a support member 4 as a "support part" located slightly below the tip 41.
2 is permanently installed. A recess 43 having a shape corresponding to the shape of the support member 42 is provided at the lower end of the body 25 of the second mask body 22.
2 is replaceably attached by inserting and fitting the recess 43 into the support member 42.

The mask plate 2 also serves as a sealing member for the nozzle 40, and the tip 41 of the nozzle 40 is brought into contact with the lower surface 2a of the mask plate 2 via a sealing member 44 for improving adhesion. The plating liquid A sprayed from the plating box 1 is prevented from leaking into the plating box 1.

A suction tube 45 is connected to a suction source (not shown) and is positioned above the mask plate 2, with an opening 46 facing the plating liquid injection opening 5 of the mask plate 2. Further, an auxiliary mask body 47 having a substantially pyramidal shape that masks the island portion 7 of the IC lead frame 3 from above is provided in the opening 46 of the suction pipe 45 by a supporting member 48, and the support member 48 serves to plate the precious metal plating target portion 8a. All of the applied plating liquid A is suctioned by this suction tube 45 so that it does not touch anything other than the part to be plated 8a.

Note that the other configurations are the same as those of the prior art, so redundant explanation will be omitted.

Next, the operation of this modification will be explained.

The plating liquid A injected from the nozzle 40 is
It rises along the body 25 of the mask body 22, and the mask plate 2 and the second
exposed without being covered by the mask body 22
Touch only the part 8a of the IC lead frame 3 to be plated and apply precious metal plating there. Next, the plating liquid A that has collided with the plating target part 8a is sucked into the suction tube 45 along the auxiliary mask body 47 by a suction source (not shown), that is, the plating liquid A is transferred from the plating box 1 to the nozzle. 40 → Plating target part 8a
→ Follow the "one-way" route called suction tube 45,
After touching the part 8a to be plated on the IC lead frame 3 and plating it with precious metal, and losing the precious metal ions, they do not directly return to the plating box 1, but are quickly discharged.

In the illustrated example (Figures 4 to 9), the plating liquid A is directed from the bottom to the top in the figure, but it may be directed from the left to the right, for example, and the plating liquid A The injection direction can be set freely.

The injection plating device according to the present invention is as described above, and has the following effects.

(a) By making the second mask body for covering the island freely attachable, the second mask body can be attached to the first mask body.
It can be easily replaced separately from the mask body. As a result, by selectively combining the first mask body and the second mask body, for example, N types of first
By preparing a mask body and n types of second mask bodies, it is possible to easily correspond to N×n types of IC lead frame patterns, and versatility is greatly improved.

(b) Furthermore, since the height position of the second mask body is freely adjustable, it can be easily applied to a type of IC lead frame in which the height of the island portion and the lead pin portion are different.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing a conventional injection plating device, FIG. 2 is a partially enlarged perspective view showing the positional relationship between the mask plate and IC lead frame in FIG. 1, and FIG.
The figure further shows a partially enlarged perspective view of a conventional injection plating device corresponding to FIG. 2, FIG. 4 is a schematic sectional view corresponding to FIG. 1 showing an embodiment of the present invention, and FIG.
FIG. 4 is a partially enlarged perspective view showing how the second mask body is attached to the nozzle, FIG. 6 is a schematic sectional view corresponding to FIG. 1 showing another embodiment of the present invention, and FIG.
FIG. 6 is a partially enlarged perspective view showing how the second mask body is attached to the nozzle; FIG. 8 is a schematic enlarged sectional view showing a modification of the two embodiments shown in FIGS. 4 to 7; FIG. 9 is a partially enlarged perspective view showing how the second mask body is attached to the nozzle. 1... Metsukibox, 2... Mask board [1st
mask body], 3...IC lead frame, 4...pressing plate, 5...plating liquid injection opening, 6, 20, 3
0,40...Nozzle, 7...Island part, 8...
...Lead pin part, 8a...Platching target part, f...
...Outermost periphery of the part to be plated, A...Plating liquid, 2
2...Second mask body, 23...Sealing material, 24...
...Support member, 45...Suction tube, 47...Auxiliary mask body.

Claims (1)

[Claims] 1. An IC lead frame, which is an object to be plated,
The island part and the tip of the lead pin part facing around the island part are covered with a first mask body, and the island part is covered with a second mask body, and the nozzle provided in the box is covered with a first mask body. In a spray plating device configured to spray plating liquid onto areas not covered by each of the first and second mask bodies, the second mask body is provided with a recessed portion or a threaded portion at the lower end. An injection plating device characterized in that the spray plating device can be attached to a plating box or a support portion fixed to a nozzle through a recess or a threaded portion so that its height can be adjusted.