JPS5952707B2 - Manufacturing method for molding molds - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a molding die having a highly accurate fine pattern.

Today, many molded products, such as plastic processed products, are on the market, but all of them are molded by, for example, press processing using a mold called a metal mold, so it takes a lot of money to make the molded product. Molds have become indispensable.

There are also many examples where plastic technology is used, and the molds are made using precision processing technology. A lenticular lens (plastic lens) is a typical example made using such a mold. Generally, this lens is made of plastic arranged in a semi-cylindrical shape, and is also called a kamaboko lens, and is a kind of plastic lens. Traditionally, the molds required to make lenticular lenses have been made by marking the surface of a mirror-polished metal plate with a diamond needle.

However, this type of technology has a drawback in that its accuracy is limited, and the pitch that can be obtained with today's technology is only a few tens of microns, and the manufacturing process is complicated. The present invention has been made in view of this point, and uses a method that is completely different from conventional technology, applying microfabrication technology used in the semiconductor field, to achieve precision that was previously unattainable. The present invention provides a method for manufacturing a molding die that can be easily obtained.

An embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 5.

First, to explain the outline of the present invention, an insulating film sufficient to form a predetermined groove is provided on a silicon substrate, and then an etching-resistant film is formed using photoresist on the insulating film using a photolithography method. This is immersed in an insulating coating etching solution and the insulating coating is etched to form a predetermined groove, thereby forming a mold.

In this process, the most preferable method to satisfy the spherical curvature required for molded products such as lenticular lenses made using this mold is to create a thickness gradient in the photoresist film by photolithography. By etching this, an insulating film proportional to the photoresist film thickness is formed. For sumo wrestlers, it is very difficult to achieve this. Therefore, in the present invention, instead of this, a method of etching the insulating film in a stepwise manner is used. Next, the details will be explained according to the order of each process shown in FIGS. 1 to 5.

First, in FIG. 1, an insulating film, for example, a silicon oxide film 2 having a thickness of 5,000 μm, is formed on a silicon substrate 1. After coating an etching-resistant film, that is, a photoresist film, on this silicon pentoxide film 2, the photoresist film is exposed to light through a mask having a predetermined pattern, and then developed. The silicon oxide film 2 is etched by immersing it in an etching solution consisting of ammonium fluoride and hydrofluoric acid mixed in the same proportions to form a groove 3 having a width of, for example, 13 μm and a depth of approximately 1000 to 1500 mm, as shown in FIG. form. Furthermore, in order to make the groove as close to a spherical surface as possible, the width is set to, for example, 25 mm as shown in Figure 3 in the same manner as described above.
Groove 4 whose depth reaches one main surface of silicon substrate 1 at μ
form. Subsequently, a resin 5 is applied as shown in FIG. 4 in order to smooth the difference in level between the grooves 3 and 4. The mold is basically completed through the steps up to this point, but when molding using such a mold, in order to improve the releasability between the mold and the molded product, as shown in Figure 5. A metal film 6 such as copper, gold, or zinc is deposited on the resin 5 by, for example, a vacuum deposition method. As is clear from the above description, according to the method for manufacturing a molding die according to the present invention, a predetermined groove is formed by etching an insulating film provided on a silicon substrate stepwise by photolithography. By forming the grooves and applying resin to curve the grooves so that the cross section becomes approximately semi-cylindrical, it is possible to improve the accuracy of fine patterns, which had been a problem in the past, and to improve the accuracy of the grooves. The process is simplified as the depth can be easily adjusted, there is no need to polish the surface of the mold that was required in the conventional method, and the process can be done in one go without the need for the repeated time required for tool bit processing. Therefore, a manufacturing method with extremely good workability and low cost can be obtained.

In the above embodiment, etching was carried out in two stages to form the groove so that the cross section became semi-cylindrical. The accuracy may be increased. In addition, the resin applied to the groove may be made to use a high viscosity resin depending on the level difference of the groove to be formed, if the level difference is large, and a low viscosity resin if the level difference is small. As a result, a smooth semi-cylindrical shape can be obtained, and the flat portion between the grooves can be prevented from becoming curved, thereby achieving desired flatness. Further, the resin may be a thermosetting resin such as epoxy or an ultraviolet curable resin, and if the resin used is suitable for release from the mold, the metal film deposited thereon may be omitted. obtain. Furthermore, although a case has been described in which a silicon oxide film is used as the insulating film, other insulating films such as silicon nitride or silicon carbide may also be used.

[Brief explanation of the drawing]

1 to 5 are process diagrams showing one embodiment of the present invention in order of each step. 1 is a silicon substrate, 2 is a silicon oxide film, 3 and 4 are grooves,
5 is a resin, and 6 is a metal film.

Claims (1)

[Claims] 1. Prepare a substrate with an etched surface, and form a predetermined groove by etching the surface of the substrate stepwise by photolithography. A resin is applied to the groove to curve the groove, and its cross section is A method for manufacturing a molding die, characterized in that the mold is formed into a semi-cylindrical shape.