JPS5852035B2 - Receiving member in partial plating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a receiving member in a partial plating apparatus for applying partial plating to an electronic component frame such as an ICIJ-de frame.

In recent years, electronic components have become increasingly integrated into IC-LSIs, and their production is increasing in large quantities and in a wide variety of products.

As the precision of plating progresses, the price of precious metals such as gold and silver for plating has soared, and from the perspective of saving precious metals, conventionally the entire surface was plated, including unnecessary parts, but now only the necessary parts are plated. There is a rapid shift to partial plating.

The most important requirements for performing this partial plating are precision and high-speed plating finishing, as well as rapid response when changing the plating pattern.

However, the conventional nozzle method, in which the frame of the object to be plated is placed on a receiving member with patterned holes corresponding to the areas that require plating, or a sealing member with patterned holes on its upper surface. However, the partial plating means in which the plate is held between a holding member from above and a plating solution is jetted from a nozzle provided in a hole in the receiving member has the following problems.

(2) A conventional nozzle is provided in a hole in a receiving member with an open periphery for liquid discharge.

As a result, air gets mixed into the jet liquid, creating air pockets between the frame and the part to be plated, which tends to result in unplated parts, and also causes loss of flow velocity due to collision between the returning liquid and the jet liquid.
The splashing of the liquid stream tends to cause uneven plating and poor coverage.

＠Nozzles are generally cylindrical with a cross section of ○ shape, so the momentum of the jet liquid is strongest in the center of the ○ shape and the ion exchange is active, but the momentum of the jet liquid decreases concentrically from there. However, the plating film thickness is uneven, being thicker at the center and thinner at the periphery.

In particular, when the part that requires plating is a mouth shape, the variation in film thickness between the center and the four corners is even greater.

When the shape, spacing, etc. of the parts of the frame that require plating are changed in response to changes in the use, properties, model, etc. of QIC, the nozzle method requires changes in nozzle diameter, position, nozzle support member, masking pattern, and receiver. It is necessary to replace parts, etc., and the associated costs and adjustment time are almost the same as replacing with a new device.

■Also, since the anode serves as a nozzle, the effective area cannot be made large, and the distance between the anode and the object to be plated cannot be kept close, and the drained liquid hits the anode and impedes the flow rate, resulting in poor plating efficiency. This is also an obstacle to increasing the speed of plating.

As mentioned above, the partial plating equipment using the conventional nozzle method is
The accuracy of finishing, plating efficiency, quick response to pattern changes, etc. are changing day by day, becoming more detailed, and mass consumption.
It is in a very unbalanced situation as a means for partial plating on CIJ-frames, etc.

The present invention relates to partial plating means for IC lead frames and the like, and is an object of the present invention to solve the above-mentioned problems.

In other words, its purpose is to use it as a means for partial plating on frames for electronic components, which are becoming increasingly finer day by day. Eliminates poor coverage, increases the area of the anode, and allows it to be placed close to the object to be plated, resulting in more precise plating, improved plating efficiency, and uniform film thickness over the entire area that requires plating. An object of the present invention is to provide a receiving member for a partial plating device that can easily and quickly respond to pattern changes.

The present invention will be explained below with reference to illustrated examples.

Reference numeral 1 denotes an outer tank which is oblong in shape with an opening at the top, and a constant pressure tank 2 which is also open at the top and has an oblong shape in the center of its lower part.

The length of the constant pressure tank 2 is longer than the expected longest length of the IC lead frame 3 to be plated, and after that, the upper ends of the left and right side plates 4 are respectively used as supporting surfaces 5.

A is a receiving member, which is composed of a separable lower unit 6 and upper unit 7.

The lower unit 6 has cutouts at the lower portions of the front, rear, left and right sides of its lower half, so that the remaining lower part 8 can be engaged with the constant pressure tank 2 from above, and each side plate of the constant pressure tank 2 is cut out at each cutout lower surface 9. It can be supported in close contact with the support surface 5 of No. 4.

Further, in the lower part 8, a liquid introduction groove 10 is formed which is continuous in the longitudinal direction and opens larger toward the bottom, and plating liquid passage holes 11 are formed at the top and bottom of the unit 6 at equal intervals in the longitudinal direction. to form many pieces.

Anodes 12 are disposed horizontally on the upper surface of the unit 6 along both sides of the liquid passage hole 11.

On the other hand, the upper unit T can be placed on the lower unit 6, and has a hemispherical large hole 13 communicating with each of the liquid passage holes 11 and containing the anode 12 portion in the lower part, and a liquid jet hole 14 communicating with the large hole 13. The formed and opened upper part has patterned hole portions 15 corresponding to areas requiring plating.

Further, each of the large holes 13 is formed with a drainage hole 16 so as to communicate outwardly on both sides of the upper unit 7, and the size of the drainage hole 16 is preferably slightly wider than the pattern hole portion 15.

1T is a holding member which can be raised and lowered by an air cylinder (not shown), and has a sealing material 18 pasted on its lower surface and a cathode (not shown).

19 is a plating liquid main tank, and the plating liquid is sent to the constant pressure tank 2 via a pump 20 and a liquid supply pipe 21.

Reference numeral 22 denotes a return pipe for returning the plating solution stored in the outer tank 1 to the water tank 19.

In the above configuration, the upper unit 7 of the receiving member A is prepared in advance in several types with different pattern hole portions 15 to accommodate differences in size, shape, etc. of the portions of the lead frame 3 that require plating. be.

The material of the receiving member A is made of synthetic resin that is resistant to plating liquid, but the upper unit 7 in particular should be made of a slightly soft material.
Alternatively, in the case of a hard material, it is desirable to form a sealing coating on the upper mounting surface or to mount a sealing plate with patterned holes.

In addition, if the joint surfaces between the upper unit 7 and the lower unit 6 and the joint surfaces between the lower unit 6 and the upper surface of the side plate 4 of the constant pressure tank 2 are in close contact, the upper unit 7 The lower part 8 of the upper unit T may be engaged with the inside of the tank 2, or conversely, the tank 2 may be sandwiched between the lower part of the upper unit T.

The size of the hemispherical large hole 13 of the upper unit 7 is such that the maximum inner diameter of the lower part is slightly larger than the distance between the outer ends of the anodes 12 on both sides of the liquid passage hole 11, and the height of the hole 13 is set to be larger than that of the upper part. It is desirable that the liquid jet hole 14 be formed at a shallow depth.

Next, the action and effect of the present invention will be explained using the above-mentioned actual case.

First, place the lower unit 6 of the receiving member A on the constant pressure tank 2,
The upper unit 7 is placed thereon, and this upper unit 7 is selected to have a hole pattern 15 corresponding to the size, shape, etc. of the portion of the IC lead frame 3 to be plated that requires plating.

Then, the lead frame 3 is placed on the upper unit 7 so that the part that requires plating matches the pattern hole 15, and after sealing by lowering the presser member 17 from above,
All that is required is to operate the pump 20.

As a result, the plating solution in the water tank 19 once enters the constant pressure tank 2, reaches a constant pressure, the liquid level rises, and flows into the liquid passage hole 11 from the liquid introduction groove 10 of the lower unit 6 of the receiving member A.

The plating liquid reaches the upper pattern hole portion 15 from the liquid jet hole 14 through the hemispherical large hole 13 of the upper unit 7, collides with the portion of the lead frame 3 that requires plating, and the plating is rolled over.

After that, the plating solution flows from the shallow liquid jet hole 14 immediately along the inner peripheral surface of the hemispherical large hole 13, and flows through the drainage holes 16 on both sides.
and is discharged to the side of the upper unit 7.

In the above case, the anodes 12 are provided on both sides of the liquid passage hole 11 on the upper surface of the lower unit 6, and are within the range of the large hemispherical hole 13 of the upper unit 7, so the plating liquid flows in and is discharged in a jet manner. The anode 12 does not become an obstacle at all during the process, does not hinder the flow rate of the plating solution, is close to the lead frame 3 that is the object to be plated, and has a large effective surface area as an anode, resulting in faster plating. This improves plating efficiency.

Further, the drainage hole 16 is provided near the jet hole 14, and it is also formed to have the same width as the pattern hole portion 15.
The plating solution is discharged evenly and immediately without stagnation in any part of the pattern holes 15.

Therefore, the liquid after colliding with the lead frame 3 will not mix with the jet liquid, and air will not be mixed into the jet liquid.

Note that the liquid that has flowed out of the upper unit 7 is once collected in the outer tank, and then returns to the water tank 19 via the reflux pipe 22 and is circulated.

After that, determine the size and area of the lead frame 3 that requires plating.
If the shape etc. has been changed, choose one with a pattern hole 15 corresponding to the changed plating area from among several types of upper units 7 of the receiving member A prepared in advance. If you replace it with that, you can plan partial plating in the same way as above, leaving everything else as is.

Next, although the above actual case is for intermittent partial plating on the lead frame 3, if band-shaped partial plating is to be applied, at least the upper unit 7 should be replaced with one with a different structure. .

The upper unit 7 is replaceably placed on the lower unit 6 as shown in FIG. 13, a slit-like liquid jet hole 14 which is connected to the slit-like pattern hole at the upper part, and a drainage hole 16 from the large hole 13 to the outside of the unit 7.

When plating the upper unit 7 by placing it on the lower unit 6 described above, the plating solution is passed through the plating solution passage hole 11 of the lower unit 6 into the kamabot-shaped large part of the upper unit 1 in the same manner as described above. The liquid enters the hole 13, passes through the slit-shaped liquid jet hole 14, reaches the slit-shaped pattern hole 15, and collides with the lead frame 3, so that the band-shaped partial plating is rolled up.

Thereafter, the plating solution is immediately discharged from the shallow liquid jet hole 14 to the outside of the unit 7 from the drainage holes 16 on both sides along the inner circumferential surface of the large semicylindrical hole 13.

In this case, as in the above-mentioned actual case, the presence of the anode 12 does not become an obstacle during the process of jetting and discharging the plating solution, and does not impede the flow rate of the solution. Since the is large, the plating efficiency is improved.

Further, since the drainage hole 16 is provided in a large size near the jet hole 14, the plating solution is discharged evenly and immediately without stagnation.

Note that normally there is no need to replace the lower unit 6, but if the intervals between the plating liquid passage holes 11 of the lower unit 6 are wide,
Therefore, if there is a possibility that non-uniform portions will occur in the flow of the plating solution when performing band-shaped plating, the lower unit 6 may also have a slit-shaped plating solution passage hole.

Therefore, the present invention has the following effects.

■ According to the present invention, there are no unplated parts or variations in plating, and the plating can be plated with good coverage and precision and efficiency.

That is, in the conventional nozzle method, a nozzle is provided in a hole of a receiving member, and the periphery thereof is left open for liquid discharge.

As a result, there are problems such as air being mixed into the jet liquid, resulting in unplated areas due to air pockets, and loss of flow velocity due to splashing of the liquid flow and collision between the jet flow and the exhaust flow, resulting in uneven plating and poor plating efficiency. Ta.

On the other hand, in the present invention, the plating solution communicates from the constant pressure chamber and reaches the liquid jet hole of the receiving member, so there is no mixing of air, and the liquid flow does not become droplets, so plating is required in a completely continuous column of liquid. Collision in place.

Moreover, since the plating liquid flow immediately escapes from the drainage hole to the side after colliding with the area where plating is required, there is no loss of flow velocity due to collision between the jet flow and the discharge flow, and sufficient ion exchange occurs quickly, resulting in plating. Precision and speed can be greatly improved.

(6) In the present invention, the plating film thickness does not vary in thickness or thinness at any part of the pattern hole, and uniform plating without variation can be obtained.

In other words, the cross section of the nozzle produced by the conventional nozzle method is mouth-shaped, but if the pattern hole is mouth-shaped, the liquid flow is strong in the center of the nozzle and a thick plating thickness can be obtained, but the concentric surroundings are Become thin.

In particular, the plating film thickness is thinner at the four corners, and according to experimental results, it is 40 to 70% less than the center. This is because the liquid cannot escape and stagnates at the parts of the lead frame where plating is required. This is because liquid exchange is not performed sufficiently.

In contrast, in the receiving member of the present invention, drainage holes are formed at opposing positions near the pattern holes so that the liquid can flow out evenly.

Therefore, after the plating liquid collides with the area that requires plating, it is evenly and quickly discharged to the side from all parts, and there is no area where the liquid stagnates, forming a uniform plating film thickness over the entire area that requires plating. According to experimental results, the difference in film thickness when partially plating the mouth shape is less than 5%.

This is the same when applying band-shaped partial plating, and since the liquid flow is improved, uniform plating with no difference in film thickness can be achieved.

ω] According to the present invention, even if the size, shape, etc. of the parts of the lead frame that require plating are changed, it can be easily and quickly accommodated.

In other words, in the conventional nozzle method, when changing the pattern as described above, it is necessary to change the nozzle diameter, nozzle support member, and replace the masking pattern, receiving member, etc., and the associated costs and adjustment time are required to replace the new equipment. It took about the same amount of time to replace it.

In contrast, in the present invention, it is only necessary to select the upper unit of the receiving member from several types of upper units prepared in advance and replace it with the one corresponding to the part that requires plating after the change.
This makes it possible to perform desired partial plating on lead frames of different types having different sizes, shapes, etc. of the portions requiring plating.

Also, in the case of band-shaped partial plating, the upper unit can be replaced with a corresponding one, but the lower unit can also be easily changed if necessary.

Note that if the upper unit is hard or the frame is thick, and a sealing plate with patterned holes is used on the upper unit, it goes without saying that the sealing plate may be changed at the same time.

ω] The present invention can improve plating efficiency and speed up plating.

That is, in the conventional nozzle method, the nozzle also serves as an anode, so it is not possible to have a sufficient effective area for the anode, and it is also necessary to provide a space for liquid drainage, so the anode cannot be placed close to the lead frame side. Therefore, it has been difficult to increase plating efficiency or speed up plating.

In contrast, in the present invention, the anode is located close to the liquid passage hole in the lower unit and within the range of a large hole in the upper unit, such as a hemispherical or kamabot-shaped hole, while the drainage hole is formed separately in the upper unit. It is.

Therefore, the anode has a sufficient effective area, and does not obstruct the inflow and discharge of the plating solution at all.Furthermore, the anode is installed close to the lead frame, which is the object to be plated, and As a result, a high current can be passed, the flow rate of the plating solution is high, and ion exchange is active, making it possible to sufficiently improve the efficiency and speed of plating.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a partially cutaway perspective view of a plating apparatus using the receiving member, Fig. 2 is a vertical cross-sectional view of the central part of the apparatus, and Fig. 3 is the receiving member. FIG. 4 is a partially cutaway enlarged perspective view of a receiving member of a separate winding example. Drawing code, A...Receiving member, 2...Plating liquid constant pressure tank, 6...Lower unit, 7...
...Upper unit, 11...Plating liquid passage hole, 1
2...Anode, 13...Large hole, 14
...Liquid jet hole, 16...Drain hole.

Claims (1)

[Claims] 1. Consisting of a horizontally long lower unit 6 and an upper unit T, the lower unit 6 can be placed in a plating liquid constant pressure tank 2 in a sealed manner, and has a plating liquid communication hole communicating with the tank 2. 11, and an anode 12 is disposed horizontally on its upper surface in close proximity to the through hole 11, while the upper unit 7 is replaceably written on the lower unit 6, communicates with the through hole 11, and has an anode 12 disposed horizontally on its upper surface adjacent to the through hole 11. a large hole 13 including the position of the large hole 13, and a shallow liquid jet hole 14 communicating with the large hole 13 and connected to the pattern hole portion at the upper part;
A drain receiving member for a partial plating apparatus, which has a drainage hole 16 extending from the large hole 13 to the outside of the unit I. 2. The upper unit 7 is provided with a large number of patterned holes in the upper part, a shallow liquid jet hole 14 connected to each hole, and a large hemispherical hole 1 communicating with each jet hole 14 and including the position of the anode 12.
3 and a drainage hole 16 from each large hole 13 to the outside of the unit T. 3. The upper unit 7 is provided with a slit-like pattern hole in the upper part, a shallow liquid jet hole 14 connected to the hole, and a large hole 13 in the shape of a kamabok that communicates with the jet hole 14 and includes the position of the anode 12. A receiving member in a partial plating apparatus according to claim 1, wherein a drainage hole 16 is formed from the large hole 13 to the outside of the unit 7.