JPS6145162Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a mask used when partially plating decorative metal plates and lead frames for integrated circuits (hereinafter abbreviated as IC).

There are various types of decorative metal plates, including copper, iron,
In some cases, a design effect can be achieved using minimal resources by partially applying precious metal plating (gold, platinum, silver) to general-purpose metals such as stainless steel, brass, and aluminum in a desired pattern. In addition, 42 nickel alloy (Ni42%, Fe
The part (island) on which the IC chip is placed after press punching and etching a material with high thermal conductivity such as Kovar (29% Ni, 17% Co, Fe remaining), and phosphor bronze to form a predetermined pattern. Adhesive and surrounding inner leads, imparting conductivity,
Currently, parts are plated with precious metals such as gold and silver for corrosion prevention purposes. Since these precious metal platings are quite expensive, they must be applied accurately to the minimum necessary area. The present invention relates to a mask for partial plating that satisfies this requirement and has the advantage of improving workability during plating.

Conventionally, masks for partial plating have been plate-shaped, and the substrate has heat resistance and chemical resistance.
mm thick resin plate (polypropylene, polyethylene, polyvinyl chloride, acrylic, polycarbonate, epoxy resin laminate with glass fiber,
The desired holes were drilled using a numerically controlled milling machine using a polyester laminate containing glass fibers.

If used as is, the plating liquid will leak from between the plating plate and the mask plate, and the plating will be applied to areas other than the required areas. Therefore, a flexible resin such as silicone should be attached using a spray coating method or a laminating method. They were used for the purpose of ganging up on people.

Referring to FIG. 1 of the drawings, partial plating using a conventional mask will be explained using a mask plate 10 formed by applying a flexible resin layer 2 on one side of a mask resin substrate 1 as described above. , this mask board 1
The plated body 3 is installed so that the portion 4 to be plated is exposed through the opening 9 of 0. A backing plate 5 is brought into contact with the mask plate 10, the body to be plated 3, and the backing plate 5, which are held under appropriate pressure. In this state, electrolytic plating is performed by jetting a plating liquid toward the opening 9 to form an electrodeposit 6 on the surface of the portion 4 of the body 3 to be plated.

However, when a resin layer 2 such as silicone is coated on a resin substrate 1 having openings 9 in advance by means such as a spray coating method as shown in FIG. 2 will sag and create a protruding portion 7, or the mask plate 1 will not be bent far inward from the desired plated portion 4 of the body 3 to be plated.
The surface of 0 has a thickness of several 100μ to provide cushioning properties.
Since the coating was applied to a thickness of , the surface had a rough surface portion 8 with considerably large irregularities. For this reason, there was a problem in that the plating liquid entered this area, causing unnecessary plating to occur. On the other hand, the lamination method uses a rubber sheet such as silicone rubber, and after laminating it to the resin substrate 1 using silicone resin as an adhesive, holes are also made in the rubber layer to match the openings 9. Rubber layer 1 with surface 11
2 contacts the plated body 3 with almost no gap as shown in FIG. 2, so it is possible to apply plating to the desired area ^.
Since the rubber layer 12 and the plated body 3 are pressed with high pressure, the contact between the rubber layer 12 and the plated body 3 is good, so there is a problem in that it takes time and effort to remove the silicone rubber from the mask plate after plating. In order to shorten this time and effort, a method of using a rubber layer 12' whose entire surface is roughened as shown in Fig. 3 has been considered. The rubber layer 12' gets stuck between the rubber layer 12' and the body to be plated, and unnecessary parts are plated, which is economically disadvantageous, especially when precious metals are attached.
In addition, metal decorative plates had the disadvantage that the designs were blurred.

In view of these circumstances, the purpose of this invention is to accurately plate the minimum required area,
Another object of the present invention is to provide a mask for partial plating which facilitates the work of removing a plated body during plating. The present invention will be explained below using FIGS. 4 and 5. FIG. 4 shows the mask 13, the covered body 3, and the backing plate 5 of the present invention.

A desired opening 9 is formed in the substrate 1 of the partial plating mask 13 using the same processing method as the conventional method (machining method using a numerically controlled milling machine or the like). The present invention has a mask 13 on which a partially roughened rubber layer 14 is laminated. That is, it is characterized by having a smooth surface 15 around the aperture 9 (within a range of 1 mm at a minimum and 20 mm at a maximum on one side from the hole) and a moderately rough surface 16 around this area.

Having these two surfaces means that due to the function of the smooth surface 15, the edge of the desired part 4 of the body to be plated (i.e., the part of the opening 9) has a rubber layer 1.
Since the plate 4 is smooth, the plated body 3 is in close contact with the plated body 3, so there is no penetration of the plating liquid into this gap, and the plate can be plated on a precise area, which is economical and allows for the relimitation of patterns. Excellent in this respect. In addition, since the contact area with the plated body 3 is small at the rough surface 16 and the affinity is poor, it is easier to remove the plated body 3 from the partial plating mask 13 after plating is completed than from this part. It has the advantage of being able to be peeled off quickly, which has the great advantage of improving work.

In this mask 13, as the material of the rubber layer 14, heat-resistant and chemical-resistant urethane, silicone, fluorine-based resin, or rubber can be used.

The method for manufacturing the mask of the present invention will be described using silicone rubber as an example. There are two ways to make silicone rubber sheets that have a partially roughened surface. As one method, a sheet 19 having a thickness of about 1 to 10 mm is prepared by kneading raw silicone rubber, a vulcanizing agent, a pigment, etc., and then hot pressing the sheet 19 between hot press molds 17 and 18 as shown in FIG. 6.

At this time, the rough surface 20 is partially etched into the mold 18 with desired dimensions by etching or sandblasting.
will be established. The other mold 17 may have either a rough surface or a smooth surface. The silicone rubber sheet 19 is
They are simultaneously vulcanized by hot pressing at a pressure of 1 to 20 kg/cm ² and a temperature of 100 to 200° C. for 10 to 60 minutes. At this time, by providing the mold 18 with the protrusions 21 and the mold 17 with the recesses 22, a perforated sheet 23 as shown in FIG. 17a can also be obtained. If there are no holes, a partially roughened sheet 24 without holes is obtained. When using the perforated sheet 23, a silicone resin is used as an adhesive so as to fit into the holes of the resin substrate 1 prepared in advance, and the sheets are pasted together so as not to be misaligned. When using the non-perforated sheet 24,
After adhering in the same manner, it is cut to match the hole in the substrate 1 using, for example, a knife or a laser beam. When using the perforated sheet 23, it is difficult to align the holes with the substrate 1, so it is used for partial plating of metal decorative plates that have relatively high tolerance for dimensional accuracy.
When performing laser cutting using a laser cutter, it is best to use one with dimensional accuracy, such as an IC lead mask. Another way to make a silicone rubber sheet with a partially roughened surface is to use mirror plates (chrome-plated iron plates) on both the upper and lower sides of the mold shown in Figure 6 to obtain a sheet that is completely smooth. After bonding to the substrate by the method described above, cutting is performed using a knife or a laser beam, and then only the area around the hole is covered with a metal plate and roughened by sandblasting to a desired size.

The thus obtained mask plate for partial plating has smooth areas around the holes that contact the object to be plated, so that the plating liquid can penetrate between the mask plate and the object to be plated. It is possible to accurately plate the set point of the body to be plated without any roughness, and since it has a roughened surface, the contact area with the body to be plated is small, making it easy to remove the body to be plated after plating is completed. There was no chance of the mask getting stuck on the mask board when removing it, leading to improved workability. The smooth surface 15 of the mask plate for partial plating of the present invention shown in FIGS. 4 and 5 is several μm.
The roughness is as follows, and the rough surface 16 is several tens of microns to several hundred microns
roughness. Moreover, the area ratio of smooth surfaces to the total area is wide, ranging from 5 to 90%, and the rest is rough surfaces.
The thickness of this rubber sheet is 0.2 to 2.0 mm. When using a silicone rubber sheet, the lower the rubber hardness, the better, 15 to 50℃ (measured with a rubber hardness meter)
is optimal. As an example of silicone rubber material
Examples include KE520-u and KE951-u (manufactured by Shin-Etsu Chemical Co., Ltd.). When using an epoxy resin board containing glass fibers, use KE12SRTV as an adhesive.
(manufactured by Shin-Etsu Chemical Co., Ltd.) by brushing several tens of micrometers, lightly placing the rubber sheet on it, and adhering it by rubbing with an iron or rubber roller to remove air bubbles. At this time, it is even better to use Brimer T (manufactured by Shin-Etsu Chemical Co., Ltd.) as a base treatment to increase the adhesive strength.

The accuracy of the plated portion is approximately 100 μm when using the sheet 23, and approximately 10 μm when using the sheet 24 and later drilling holes in the silicone sheet portion. Further, although the plating liquid is mainly made of precious metals such as gold, silver, and platinum, it goes without saying that it can also be used for base metals such as nickel, tin, and solder. In addition, plating methods include immersion plating and jet jet plating, but in both cases, the plating liquid accumulates in the opening 9 and a soluble or insoluble anode is installed facing the object 3 to be plated. The cathode lead portion is generally set on the backing plate 5 so as to be in contact with the body 3 to be plated.

By using the mask for partial plating of this invention,
For metal decorative plates, we were able to obtain patterns with better reproducibility and no bleeding compared to conventional methods.

Regarding partial plating of IC lead frames, there is no leakage of the plating to the side parts, and it is possible to obtain highly accurate precious metal plating of 10 μ or less in precise areas, and the material is 1/4 to 1 times that of conventional plating. /3 resources can be saved, and by providing a smooth surface and a rough surface, which is a feature of this invention, the time to replace the plated body after plating is completed is 1/3 to 1/2 of the conventional time. , we were able to produce significant effects such as increasing work efficiency.

In addition, the arrangement of the rough and smooth surfaces of the rubber sheet was determined under the conditions described above (a smooth surface is provided with a width of at least 1 mm and a maximum of 20 mm from the opening, and the ratio of the smooth surface to the total area is 5 to 5 mm.
90%), it is free.

[Brief explanation of the drawing]

1 to 3 are explanatory cross-sectional views showing how partial plating is performed using a conventional method mask plate, and FIG. FIG. 5 is a perspective view showing an embodiment of the mask for partial plating of the present invention, and FIG. FIG. 7 is an explanatory diagram showing an example of how to make a sheet, and FIGS. 7a and 7b are cross-sectional views showing an example of the shape of a rubber sheet used when making a mask for partial plating of the present invention. 1...Resin substrate, 2...Flexible resin, 3
... body to be covered, 4... part to be covered, 5...
... Backing plate, 6 ... Electrodeposition, 7 ... Extrusion part,
8... Rough surface part, 9... Opening part, 10... Mask plate, 11... Smooth surface, 12, 12'... Rubber layer,
13...Mask, 14...Rubber layer, 15...Smooth surface, 16...Rough surface, 17, 18...Mold, 19...
Sheet, 20... Rough surface, 21... Convex portion, 22...
Recessed portion, 23... perforated sheet, 24... non-perforated sheet.

Claims (1)

[Scope of utility model registration request] A mask for partial plating that is made by laminating and integrating a rubber sheet with a substrate, with the peripheral part of the opening corresponding to the partial plating area having a smooth surface and the other part having a rough surface.