JPS61124596A - Partial plating method - Google Patents

Abstract

PURPOSE:To perform easily, selective electroplating on a fine part by providing a laser beam irradiating conductor toward a plating part, making a plating liquid flow down along the outside periphery of the conductor, and also irradiating a laser beam on a partial plating part. CONSTITUTION:A conductor 4 for irradiating a laser beam 3 is provided on the upper part of a partial plating part 2 of a body to be plated 1. The laser beam 3 from a laser light source 9 is condensed and led into the conductor 4, and from a gap of the conductor 4 and a nozzle 6, a plating liquid 10 is made to flow down along the outside peripheral wall of the conductor 4. In this way, the plating liquid 10 is supplied to a partial plating part 2 of the body to be plated 1, and also electroplating is executed by irradiating the laser beam 3 on the partial plating part 2. In this case, an anode 11 is provided in the plating liquid, and a plating voltage is applied by using the body to be plated 1 as a cathode. By this method, the electroplating of a dot-like or linear pattern can be performed precisely and quickly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a partial plating method, in particular a method for selectively electroplating desired local parts of an object to be plated without using a mask or the like.

[Conventional technology]

Electroplating only the necessary parts of a conductive substrate such as metal is widely practiced, especially in the field of electronic components. For example, as shown in Figure 3, an IC lead frame has a tab (a) and an inner lead (b) around it.
), and a 7 outer lead (C) is provided on the outside, and an IC element such as 3i is mounted on the tab (a).
After the electrodes on the element and the tips of the inner leads (b) are wire-bonded, they are molded with epoxy or the like. In such a lead frame, All or A(+
However, due to economic efficiency and insulation failure between the leads due to AIJ migration, the wire ends of the tab (a) and inner lead (b), that is, the dotted line (d) shown in the figure, were plated.
) now only the part surrounded by 80 or 80 is sporatomettsugi. Such plating was necessary for die bonding on the tab and wire bonding of the inner leads.

As such spot plating, a method is widely used in which a rubber mask is pressed against the surface other than the plated portion, and a plating solution is sprayed onto the plated portion to carry out electroplating. However, even with sub-I-plating using this method, migration between tabs and leads and between leads could not be completely prevented.

Recently, when mounting an IC element on a tab, Sl-A (]
Instead of the eutectic bond brazing method, a method using an epoxy adhesive came to be used, and it became sufficient to plate the lead frame with Au, Ag, etc. only at the tips of the inner leads. In addition, in order to completely prevent the migration, it is necessary to attach a diameter of 0.0 mm to the tip surface of the inner lead.
It is desired to plate in a circular shape of 1 to O, Smtn.

[Problem that the invention seeks to solve]

A resist plating method is known as a method for selectively plating the minute portions of the F-type. This method performs electroplating by applying resist to the surface other than the plated parts, and as resist application requires a complicated process and a large amount of cost, it is not practical for partial plating of lead frames etc. .

Furthermore, AIJ plating is considered ideal for contacts such as switches and connectors, and in order to make economical use of it, it is highly desirable to localize electroplating only to the necessary areas, just like with lead frames. It is rare.

[Means for solving problems]

4 In view of this, as a result of various studies, the present invention has developed a partial plating method that can easily perform selective plating on minute parts, which was difficult in practice with conventional plating methods. A conductor for laser beam irradiation is provided directly above the plated area and directed toward the plated area, and the plating liquid is flowed down along the outer peripheral wall of the conductor to supply the plating liquid to the partially plated area, and the conductor This method is characterized by electroplating by irradiating the plated portion with a laser beam.

That is, as shown in FIG.
A conductor (4) is provided to irradiate a laser beam (3) toward the conductor (4). The conductor (4) passes through a plating liquid tank (5) provided above the object to be plated (1) above the nozzle (6) at the lower end, and a mirror (7) and a lens (8) are attached to the upper end of the nozzle (6). A laser beam (3) from a laser light source (9) is provided.
) is introduced to focus the light. On the other hand, the plating solution (10) is caused to flow down the outer peripheral wall of the conductor (4) from the gap between the conductor (4) and the nozzle (6). In this way, the Menu V solution (10) is supplied to the partially plated portion (2) of the object to be plated (1), and the partially plated portion (2) is irradiated with a laser beam (3) for electroplating. In this electroplating, as shown in the figure, it is preferable to provide an anode (11) in the plating solution in the plating film (5) and apply a plating voltage using the object to be plated (1) as a cathode.

Figure 2 shows two partially plated parts (2) of the object to be plated (1).
＞, (2') shows a method of electroplating at the same time, using a flexible conductor (4'), as in the case of Fig. 1, the partially plated part ( 2)
, (2') directly above and adjacent to the partially plated part (2) (2').
Conductors (4') and (4') that emit laser beams (3) and (3') toward (3) is focused by a lens (7) and divided into laser beams (3) and (3').
), (4').

In this way, both conductors (4') are connected to the nozzle (6') of the plating liquid tank (10) provided above the object to be plated (1).
, (4') an equal amount of plating solution (10) is poured out,
The conductors (4'), (4') are caused to flow down onto the partially plated parts (2), (2') by the outer peripheral walls of the conductors (4', (4')), and the conductors (4), (4') are allowed to flow down onto the partially plated parts (2), (2'). 4') from the laser beam (3).

Electroplating is performed by irradiating (3').

In the top view, (11) shows seven nodes provided in the plating solution in the plating solution tank (5).

The conductor (4) is a straight one made of 5iOz fiber or a metal tube with an internal mirror finish, and a flexible conductor (4) is used.
4') is a flexible one made of 5iOz fiber, and the partially plated part (2) of the object to be machined (1),
(2') Directly above, it is almost vertically deep. In addition, it is desirable to use a wave laser such as Ar or YAG, which has low absorption by plating solution components such as water and metal ions, as the laser light source (9), and a small laser light source with an output of several tens of watts or less is sufficient. It is.

(Function) The plating liquid flowing down along the outer circumferential wall of the conductor becomes a thin liquid stream at the end of the conductor, and spreads out as a secondary stream on the partially plated area. In addition, by irradiating the plated part with a laser beam, the surface of the partially plated part is heated, and its stirring effect significantly enhances the electrodeposition of the plated metal, increasing the local allowable current density by several tens to 1000 times. improves. This effect works effectively in combination with the agitation effect of a type of jet stream caused by the falling of the Metetsu solution, realizing ideal partial plating with high resolution.

However, if the laser beam irradiation is omitted in the lever plating method, plating will also occur in the secondary flow area, reducing the localization of the plating.

Further, according to the plating method of the present invention, plating to a thickness of about 0.5 to 5 μm required for ordinary electronic parts such as the lead frame and contacts can be completed in 1 to several seconds. Furthermore, by intermittently moving the object to be plated or the plating system and intermittent application of the plating voltage, a large number of partial platings can be performed quickly. Furthermore, linear plating is also possible by continuously moving the plate while applying the plating voltage.

〔Example〕

Using a 5iOz fiber with a diameter of 120μ and a length of 501μ, 5W was applied from the top of the fiber by the method shown in Figure 1.
A focused Ar laser beam was introduced, and the outer peripheral wall of the fiber was coated with A Ll plating solution N manufactured by Nippon Energel Hull 1- Co., Ltd.
-17 was allowed to flow down, and a phosphor bronze strip (thickness 0.06 m, width 8#I#I) plated with Ni to a thickness of 2.5μ was placed 0.1 m/ mi
The phosphor bronze strip was moved horizontally at a speed of n, and the central part was irradiated with a laser beam and the plating solution was allowed to flow down. A plating current of . As a result, the width is 0.2
5#, 1μ thick Δu-Co alloy was plated in a line. This plating condition has a high resolution and is used for small key switch contacts using the conventional resist plating method! !
A product with almost the same performance was obtained compared to the one manufactured by the manufacturer.

Moreover, the time required for plating was about 1/10th.

(Effects of the Invention) According to the present invention, electroplating of various dotted or linear patterns can be performed precisely and quickly. This not only shortens the time and reduces :j stress, but also enables smaller and more precise partial plating, which brings about remarkable industrial effects.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one example of the method of the present invention, FIG. 2 is an explanatory diagram showing another example of the method of the present invention, and FIG. 3 is a plan view showing an example of a lead frame. 1... Body to be plated 2.2'... Partially plated part 3
．． 3'...Laser beam 4.4'...Laser beam conductor 5...Plating liquid tank 6.6'...Nozzle 7...
・Lens 8...Mirror 9...Laser light source 10...Plating solution 11...Anode a...Tab b...Inner lead C.
・Outer lead

Claims (2)

[Claims] (1) A conductor for laser beam irradiation is provided directly above the partially plated part of the object to be plated and directed towards the plated part, and the plating solution is flowed down along the outer peripheral wall of the conductor to plate the partially plated part. A partial plating method characterized by supplying a liquid and performing electroplating by irradiating the partially plated portion with a laser beam from a conductor. (2) The partial plating method according to claim 1, wherein an anode is provided in the plating solution, the object to be plated is used as the cathode, and a plating voltage is applied between the anode and the cathode.