JPH02140961A - Forming method for thin plate material - Google Patents

Abstract

PURPOSE:To simply, inexpensively and rapidly form a thin plate material by totally punching in a desired pattern by half punching the material in a second step and etching it in a third step. CONSTITUTION:The whole surface of a thin plate base material 1 is coated with photoresist to form a masking layer 2, and the material 1 is inserted between a pair of punch 3 and a die 4 for forming a mold. The punch 3 is pressed to the material 1 by a press to intrude the protrusion 3b of the punch 3 into the material 1. Thus, it is not totally punched but a half punched part 1b is formed, and the layer 2 is separated. Then, the half punched material 1 is dipped in etchant E. In this case, since no masking layer is provided on the sheared section S, etching zones 5 are formed on both side faces. When the zones 5 of the both sides are connected, the part 1b is totally punched as scrap zone. Thus, the thin plate material can simply, inexpensively and rapidly be formed.

Description

[Detailed description of the invention] "Industrial application field" TECHNICAL FIELD This invention relates to a method and force for forming thin plate materials.

"Prior Art" Conventionally, IC lead frames have been manufactured using photo-etching techniques or press punching techniques. The former, that is, the IC lead frame is made using photo-etching technology! ! In order to fabricate two parts, first, a photoresist is coated on a metal plate, and then the photoresist-coated surface is exposed to ultraviolet light corresponding to the IC lead frame. Next, development is performed to form a photoresist relief image of the IC lead frame. Then, the exposed portions of the four metal plates of the photoresist relief image are etched away by etching. In order to manufacture an IC lead frame using the latter method, that is, press punching technology, first, a mold consisting of a pair of punches and a die shaped like an IC lead frame is prepared. Next, a metal plate is inserted between the punch and the die. Then, a press is used to press the die and punch out the metal plate.

``Problems to be Solved by the Invention'' By the way, in the manufacture of IC lead frames using the above-mentioned photoetching technology, there are problems such as foreign matter getting mixed in when the photoresist is fabricated, and foreign matter adhering to the photoresist during exposure. As a result, pinholes are often formed during etching, or etching defects often occur. In order to prevent such harmful effects, it was necessary to make a large investment in cleaning the working environment. Another drawback was that the etching process time was extremely long. If double-sided etching is performed, the etching processing time will be halved, but for this reason,
It was extremely difficult to form photoresist relief images that were m apart from each other on both sides of a metal plate. On the other hand, in manufacturing IC lead frames using press punching technology, extremely precise molds made of cemented carbide were required.

In addition to this, there was the problem that such precise molds could only be made by experts. For this reason, capital investment for molds has become expensive. Furthermore, it is difficult to control the residual stress generated in the mold during press punching, and therefore there is a problem in that the durability of the mold is poor.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a simple, inexpensive, and quick method for forming a thin plate material. Furthermore, it is an object of the present invention to provide a method of forming a thin plate material that can obtain a much higher yield.

"Means for Solving the Problems" The present invention includes a first step of forming a masking layer on the entire surface of a thin plate material, and a contour of a desired pattern from one side of the thin plate material that has undergone the first step. The half-blank portion is completely punched out by performing a second step of half-cutting along the contour and separating the masking layers inside and outside the contour, and etching the thin plate material that has undergone the second step. The above-mentioned problem is solved by providing a third step of doing so.

"Operation" The thin plate material is fully punched into a desired pattern by half punching in the second step and etching in the third step. According to this molding method, the burden of etching is reduced by the amount of half-blanking.

On the other hand, the burden of punching becomes lighter by the amount of etching.

Embodiment J An embodiment of the present invention will be described below with reference to the drawings.

1 to 3 show an IC which is an embodiment of the present invention.
It is a figure for explaining the manufacturing method of a lead frame.

Hereinafter, a method for manufacturing an IC lead frame according to the same embodiment will be explained in order of steps.

(1) Masking process First, as shown in Fig. 1, photoresist is uniformly applied to the entire surface of the thin plate base material 1 obtained by rolling copper or copper alloy, and masking layers 2, 2 are formed. do. Here, as the thin plate base material 1, one having a plate thickness t of 0.1 to Q, 5 mm is suitable. The above-mentioned photoresist may be a commercially available product, such as KMER from Kodak Co., O
MR, AZ made by Shibre, etc. are used.

(2) Half-blanking step In the masking step, the thin plate base material 1 on which the masking layer 2°2 has been formed is inserted between a pair of punches 3 and dies 4 that constitute a mold for an IC lead frame. Next, the punch 3 is pressed against the thin plate 1 by a press, so that the convex portion 3b of the punch 3 bites into the thin plate base material 1. Here, the convex portion 3b is pulled back in the middle of biting without cutting off the entire thin plate base material l. In this way, a half-blanked portion 1b in the shape of an IC lead frame is formed.

In addition, along with this, the masking layers 2, 2 are separated, and as shown in FIG.
It becomes. And between these, shear planes S, S,
... is intervening. In this example, the height Pl+ of the protrusion 3b of the punch 3 and the depth Dh of the four parts 4b of the die 4 are both equal to the board thickness t.
(0.1 to 0.5 mm). Also,
The width Pv of the protrusion 3b is equal to or smaller than the tip of the plate, and the width Pw of the protrusion 3b is lρ equal to or larger than the width Dv of the fourth part 4b. Further, the punch 3 and die 4 in this example have the same configuration as in plate making for printing. However, it goes without saying that a normal mold configuration may also be used.

(3) Etching step The thin plate base material I after the half-blanking step is then immersed in an etching solution E containing a ferric chloride solution, a copper chloride solution, or the like. At this time, as shown in Fig. 3, the shear planes S, S,...
・Since there is no masking layer, first, the shear planes S, S
, . . . are severely corroded by the etching solution E.

Since the shear planes S, S, . Then, when the etching zones 5 and 5 on both sides are connected, the half-opening part lb
will be removed (completely removed) as a scrap zone.

Through the above steps, an IC lead frame is manufactured.

In the above-mentioned embodiment, the case of double-sided etching was described, but instead of this, single-sided etching may be performed as shown in FIG. This single-sided etching can be performed by spraying an etching solution onto only one side of the thin plate base material.

In addition, in the above embodiments, a copper plate or a copper alloy plate is used as the thin plate base material l, but the present invention is not limited to this, and for example, an iron plate or its alloy plate, a nickel plate or its alloy plate, etc. May be used.

Furthermore, in the above embodiments, a case was described in which a photoresist was used as the masking material, but the masking material is not limited to this. As long as the film meets these conditions, a metal plating film or a sputtering film may be used.

"Effects of the Invention" As is clear from the above description, according to the method of forming a thin plate material of the present invention, the following effects can be obtained.

(1) First, it is half-blanked using a press, and then etched, so the actual board thickness for etching can be reduced by the half-blanked amount, and in addition to this, double-sided etching is performed. Therefore, the etching processing time can be significantly shortened compared to the conventional manufacturing method using only photoetching technology. In addition, in this type of molding method, the etching process was rate-limiting, but according to the method of the present invention, as described above, the etching process time can be significantly shortened.
Overall, the manufacturing time can be shortened.

(2) Also, as mentioned above, the actual plate thickness for etching is thinned by the amount of half-blanking (as a result,
The amount of corrosion on thin plate materials is also reduced. Therefore, deterioration of the etching solution can be delayed.

(3) The mold for half punching does not require the punch and die to overlap with high precision, so the dimensional accuracy is -
It's rough and good. Therefore, the manufacturing cost of the mold becomes low.

(4) Since the punch does not completely punch out the material, the punch will not dig into the material beyond the thickness of the thin plate material. Therefore, the life of the punch can be extended.

(5) There is no need to drop scraps as in the case of complete punching, and there is no occurrence of cracks, making it easy to process very close parts.

(6) Compared to the case of complete punching, the height of the convex portion of the bonder can be lowered, which increases the buckling strength, making it possible to process finer slits than with normal punching.

[Brief explanation of the drawing]

1 to 3 show an IC which is an embodiment of the present invention.
FIG. 1 is a diagram used to explain a method for manufacturing a lead frame, and FIG. 1 is a diagram used to explain a masking process, FIG. 2 is a diagram used to explain a half-cutting process, and FIG.
The figure is a diagram for explaining the etching process, and FIG. 4 is a diagram showing the etching process in one embodiment of the same embodiment. !・・・・・・Thin plate material! b...Half-opening part, 2
゜2a, 2b... Masking layer.

Claims (1)

[Claims] A first step of forming a masking layer on the entire surface of the thin plate material,
a second step of cutting half of one side of the thin plate material that has undergone the first step along the contour of a desired pattern and separating the masking layers inside and outside the contour; A method for forming a thin plate material, comprising a third step of completely punching out the half-blanked portion by etching the thin plate material that has undergone the steps of (1).