JPS59188952A - Manufacture of lead frame - Google Patents

Abstract

PURPOSE:To enable to immediately confirm when the positional slippage of plating generates by a method wherein the position indicating parts of penetration holes, etc. showing the boundary of the plated region are previously formed at the place other than the part becoming a lead frame form of a metallic band strip. CONSTITUTION:The position indicating parts 12 are provided on the metallic band strip 10 in the longitudinal direction at fixed intervals and surround the plated regions 14 of partial plating to be applied, consisting of a plurality of penetration holes bored in the place other than the part becoming the lead frame form. The metallic band strip 10 thus previously provided with the indicating parts 12 showing the boundary of the region 14 is made to run in a series of plating processes, thus applying the partial plating in the regions 14. Such a manufacture enables to judge it even by visual observation at a glace whether the partial plating is exactly applied to a desired plated region or not and then enables to immediately cope with the accident in the case of the slippage of plating position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a lead frame, and more specifically, the present invention relates to a method for manufacturing a lead frame, and more particularly, before forming a metal strip into a lead frame shape by press working or the like, the internal lead portions of the metal strip are , plating of parts that are to become element attachment parts, external lead parts, etc. In products where partial plating is applied to the necessary parts and then formed into a lead frame shape by press processing etc., the partial plating to be applied before partial plating is applied. By providing a position indicator such as a through hole to indicate the boundary of the area, it is possible to check at a glance whether the partial plating position to be applied is accurate or not, eliminating plating defects and manufacturing lead frames with high yield. The present invention relates to a method for manufacturing a lead frame.

When manufacturing a lead frame, first a metal strip is formed into a lead frame shape by pressing or etching, and then predetermined portions are applied to the parts that require plating, such as the internal lead part, the element f bow part, and the external lead part. There is a method of plating. In addition, in order to prevent deformation of the lead frame shape during the plating process, contrary to the above, it is necessary to plate the parts that will become the internal lead part, element attachment part, external lead part, etc. at the stage of forming the metal strip. There is a method in which predetermined partial plating is applied to corresponding parts, and then the lead frame shape is formed by press working or the like.

In either case, it goes without saying that the position of the partial plating must accurately match the predetermined shape of the lead frame.

In order to apply the above-mentioned partial plating, feed holes at specified pinch points on both sides of the metal strip, feed the metal strip intermittently based on these holes, and perform partial plating at predetermined intervals. I am trying to apply it.

However, when performing multiple types of plating in a continuous process, such as silver plating or gold plating on the element attachment part and internal lead part, and tin plating or solder alloy plating on the external lead part, the plating line The length of the metal strip can be as long as 20 meters, and during this time, the metal strip sometimes gets caught in a part of the feeding mechanism and flows while being misaligned, and partial plating is applied continuously to the misaligned position. There is a real problem of large quantities of defective products.

Even in this case, when the former manufacturing method is used, the partial plating is directly flowed onto the lead frame shape, so it is possible to immediately check whether the plating position is accurate or not, and it is possible to deal with accidents and the like.

However, when using the latter manufacturing method, there is no guideline as the partial plating is poured directly onto the metal strip.
It is not easy to visually check whether the plating position is correct or not, measurement confirmation takes time, and even if a reference gauge is used to determine whether the plating position is correct or not, the plating may not be done at the correct pitch after the position has shifted. (However, it is difficult to confirm because the position is continuously shifted).

The present invention has been made to solve the above-mentioned difficulties of the latter manufacturing method, and its purpose is to be able to visually confirm any misalignment of the plating, and to be able to quickly deal with accidents, etc. , provides a lead frame manufacturing method that can manufacture lead frames with a high yield, and its features include position indicator parts such as through holes that indicate the boundaries of rough plating areas, corresponding to the areas to be plated,
After the metal strip is provided in a part other than the part that will become the lead frame shape, the required partial plating is performed.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a metal strip 10 used in the method of the invention. 12
are position display parts provided on the metal strip 10 at predetermined intervals in the longitudinal direction thereof, and are perforated in areas other than the part that will become the lead frame shape, surrounding the plating area 14 of the partial plating to be applied. It consists of multiple through holes.

The through hole may be a round hole or a square hole.

In the illustrated example, the through hole is bored in a punched part between the leads that will become the internal lead part 16 in a later process, and the internal lead part 1
6 and the necessary plating area 14 of the element attachment part 18 inside thereof.
It is set up around.

Note that the position display section 12 may be located in the plating area 14 depending on the case.
Alternatively, one through hole may be provided at each of the four corners of the plating area 14, or one through hole may be provided at each of the three corners of the plating area 14.
The sides may be indicated, or even two may be provided to indicate only one side of the plating area 14''.Furthermore, instead of a through hole, a groove, a recess, a protrusion, etc. (
(not shown) may be provided at a location other than the portion forming the lead frame shape to define the boundary of the plating region 14.

Incidentally, reference numeral 20 denotes feed holes provided with a constant pitch on both side edges of the metal strip 10.

The above position display section 12. The feed hole 20 is accurately formed in the metal strip 10 by continuous press working.

The metal strip 10 provided with the position indicator 12 indicating the boundary of the plating area 14 in advance is passed through a series of normal plating processes, and the plating area 14 is partially plated with, for example, silver. Partial plating can be performed using a conventional method using a comb mask or the like. Even if the partial plating deviates from the position display section 12 for some reason, it can be immediately confirmed visually using the position display section 12 as a guide, so the plating work can be stopped and appropriate countermeasures can be taken. . After that, using an appropriate mold, align the plated portion of the partially plated metal strip 10 to the desired plating area of the lead frame, and press with a press.

In addition, for the external lead portion 22, necessary plating such as tin plating is applied at the same time during the above series of plating steps. The plating on the external lead portion 22 may also be performed with high positional accuracy), or the necessary tin plating or the like may be applied at an appropriate stage in the subsequent process.

Alternatively, a position display section is provided on the external lead section 22 to indicate only the plating area (not shown), and the tin plating or the like corresponding to the external lead section 22 and the internal lead section 16. Even if silver plating or the like corresponding to the element attachment portion 1B is plated in a series of plating steps, the accuracy of the plating position can be similarly quickly confirmed.

Alternatively, the internal reat portion 16. Element attachment part 18
Of course, both the position display section 1-2 indicating the plating area 14 corresponding to the plating area 1-2 and the position display section (not shown) indicating the plating area of the external lead section 22 may be provided.

As described above, according to the lead frame manufacturing method according to the present invention, it is possible to visually determine whether or not the partial plating is accurately plated on the desired plating area, thereby preventing accidents when the plating position shifts. This has the remarkable effect of being able to immediately deal with problems, eliminate plating defects, and manufacture lead frames with a high yield.

Although the present invention has been variously explained above with reference to preferred embodiments, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. It is.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment of a metal strip provided with a position display section. 10... Metal strip, 12... Position display section. 14... Plating area, 16... Internal reat part,
18... Element attachment part, 20... Feed hole. 22...External lead part.

Claims (1)

[Claims] ■ Plating the parts that will become the internal lead part, element attachment part, external lead part, etc. when the metal strip is formed into a lead frame shape. Apply the necessary partial plating in advance according to the necessary parts, and then press. In a method for manufacturing a lead frame in which a desired lead frame shape is formed by processing or etching, a position indicating portion such as a through hole indicating the boundary of the plating region is placed in advance on a metal strip, corresponding to the plating region to be plated. A method for manufacturing a lead frame, characterized in that the required partial plating is performed after the lead frame is provided at a location other than the portion that will form the lead frame shape.