JPH0159358B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an etched product.

There are various types of processed products that are manufactured by selectively etching a metal plate using a corrosion-resistant film to obtain a predetermined pattern, and metal conductive plates are one example of such processed products. . A metal conductive plate is also called a lead frame, and as shown in Figure 1, it has a pattern consisting of a large number of thin branch-like metal strips 2 made by removing unnecessary parts of a thin metal plate by corrosion.
This metal strip 2 is later connected to a wafer chip on the wafer chip mounting portion 3 by wire bonding or the like. The thickness of such metal strips 2 is on the order of several tens of microns, and a large number of patterns are usually formed on one metal plate, resulting in a crowded state as a whole. Regardless, extremely strict dimensional accuracy is required.

To form such a lead frame by etching, a common method is to form a corrosion-resistant film on the necessary parts of the metal plate and remove the metal in unnecessary parts by chemical etching. As shown in Figure 2, when using this method, even if the shape of the corrosion-resistant film is made to exactly match the required pattern shown by the imaginary lines, in the product actually obtained by etching, as shown in the solid line, the metal strip The corners of 2 are rounded due to side etching, making it difficult to create sharp corners. When creating a master plate for forming a corrosion-resistant film, the conventional method is to draw the necessary pattern 2 as shown in Fig. 3b, and then fill in unnecessary parts as shown in Fig. 3a ( Hatching method) or the required pattern 2 as shown in Figure 4b.
In order to draw the outline shown in Figure 4a, a relatively thick line is used (thick line contour method is used).In addition, line width accuracy and shape changes, especially shape changes due to the side etching of the corners mentioned above, are taken. For this purpose, a special pattern 5 called a serif as shown in Fig. 5 is added to the corner part, or a bridge part 6 (Showa 57) is added to the corner part as shown in Fig. 6.
Attempts have been made to solve the problem by adding patterns other than the original, such as creating a pattern (see Patent Application Publication No. 26169, 2013) to prevent changes in shape due to side etching. However, when an etched product is manufactured using an original plate created by the hatching method, the amount of side etching in the densely patterned area and the sparsely patterned area differs markedly, making it difficult to produce a standard product. It is difficult to create, requires correction on the original plate, and is extremely complicated. Moreover, the number of parts to be etched increases, and the etchant becomes fatigued.
Furthermore, even in a method of drawing the outline of a pattern using relatively thick lines (thick line outline method), the outlines overlap in areas where the pattern is dense, resulting in thicker lines and a larger amount of side etching. Therefore, corners tend to become rounded particularly in areas with dense patterns. In addition, adding special patterns that are not present in the original, such as serifs and bridges, complicates the creation of the master plate, and the side etching speed changes because the line width of unnecessary parts differs, resulting in poor line width accuracy. It is bound to have an impact.

For this reason, it is possible to easily obtain high-quality etched products with sharp required patterns based on standards, and the fatigue of the etchant during etching is extremely low, thus extending the life of the etchant. It is desired to develop a method for manufacturing etched products that can be made for a long time and is economically advantageous.

This invention was made in view of the above circumstances, and it is possible to easily obtain a high-quality etched product having a sharp required pattern based on the standard, and to reduce fatigue of the etching solution during etching. It is an object of the present invention to provide an economically advantageous method for manufacturing etched products, which has a significantly lower amount of etchant and can therefore extend the life of the etchant.

Corresponding to this object, the method for producing an etched product of the present invention is a method for producing an etched product in which a necessary pattern is obtained by etching a metal plate using a corrosion-resistant film, the method comprising: forming the corrosion-resistant film; On the original plate for printing, an image area for non-corrosion film formation that follows the outline of the required pattern through the offset amount of side etching is drawn along the axis line, and the image area is drawn at the corner of the pattern or the adjacent image area. It is characterized by the use of discontinuous drawings in areas where the drawing areas are close to each other.

Hereinafter, details of the present invention will be explained with reference to the drawings showing one embodiment.

In FIG. 7, 11 is a lead frame as an example of an etched product, and the lead frame 11 is a metal plate that is etched using a corrosion-resistant film to remove unnecessary portions 12 and form metal strips 13 in the required pattern. This is what I did. As shown in FIG. 8, the original plate 14 for forming the corrosion-resistant film has an image area 15 for non-corrosion-resistant film formation that follows the outline of the metal strip 13 of the required pattern with a side etching offset amount d. Draw with a thin line of 200μm or less. However, the image portion 15 is discontinuous at a portion 17 corresponding to the corner portion 16 of the metal strip 13 or at a portion where adjacent image portions 15 come close to each other.

When a metal plate is etched using the corrosion-resistant film formed by the master plate constructed in this way, a corroded area 18 is formed along the image area 15 on the metal plate as shown in FIG. The corroded portion 18 becomes thicker than the image area 15 due to side etching, and as a result, the inside of the corroded area 18 matches the desired contour of the metal strip 13, and the discontinuous portion of the image area 15 also forms on the side. As a result of etching, the corroded part 18 is continuous, and the unnecessary part 12 is replaced by the necessary metal strip 1 by the corroded part 18.
It is separated from 3 and falls off, and finally the desired metal strip 1
Get 3.

In this way, in the method for manufacturing etched products of the present invention, it is not necessary to add patterns that are not on the original, such as serifs or bridges, on the original to obtain the desired product shape, and This can be done by deleting a part, so it is extremely easy to create an original version. Furthermore, it is possible to easily obtain high-quality etched products having sharp required patterns based on standards. Moreover, since etching is carried out only within the thin corroded area 18, and there is no need to remove all unnecessary parts, fatigue of the etchant is significantly reduced, and the life of the etchant can therefore be extended, making it economical. It is also advantageous.

It goes without saying that the arrangement of the image portion 15 and the discontinuous portion is not limited to that shown in FIG. 8, and various selections as shown in FIGS. 10 to 14 are possible.

[Brief explanation of drawings]

Fig. 1 is an enlarged plan view showing an example of a lead frame, Fig. 2 is an enlarged plan view showing metal strips of the lead frame, Fig. 3 is an illustration showing the hatching method, and Fig. 4 is an explanation showing the thick line contour method. 5 is an enlarged plan view showing serifs, FIG. 6 is an enlarged plan view showing a bridge portion, FIG. 7 is an enlarged partial plan view showing a lead frame related to an embodiment of the present invention, and FIG. FIG. 9 is an enlarged partial plan view showing an etched state of a lead frame in accordance with one embodiment of the present invention; FIG. An explanatory diagram showing a drawing diagram of an original plate related to the example, FIG. 11 is an explanatory diagram showing a drawing part of an original plate related to another embodiment, and FIG. 12 is an explanatory diagram showing a drawing part of an original plate related to another embodiment. Explanatory diagram, 1st
FIG. 3 is an explanatory diagram showing the image area of the original plate related to another embodiment, and FIG. 14 is an explanatory diagram showing the image area of the original plate related to another embodiment. 11... Lead frame, 12... Unnecessary part, 13
...metal strip, 14...original plate, 15...image area, 16...corner area, 17...corresponding area, 18...corroded area.

Claims (1)

[Claims] 1. A method for manufacturing an etched product in which a required pattern is obtained by etching a metal plate using a corrosion-resistant film, the original plate for forming the corrosion-resistant film being offset by side etching to the outline of the required pattern. The image area for non-corrosion film formation that runs through the pattern is drawn as a thin line, and the image area is drawn discontinuously at the corner part of the pattern or at the part where the adjacent image areas come close to each other. A method of manufacturing an etched product characterized by using etched products.