JPH11236694A - Production of injection molding die for fine parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an injection molding die having many fine side walls by coating the surface of a transparent substrate having an opaque electrically conductive layer for forming side walls of a prescribed shape with a photosensitive insoluble material, back-exposing and patterning it, successively laminating a sacrificial layer and an electroforming plating layer on the opaque electrically conductive layer and thereafter separating the electroforming plating layer. SOLUTION: On the surface of an opaque substrate 10 composed of borosilicate glass, an opaque electrically conductive layer 20 composed of gold pattered to a desired shape for forming side walls are formed. So as to cover this opaque electrically conductive layer 20, the photosensitive insoluble material is applied, from the opposite side of the glass substrate 10, back exposure is executed, and a photosensitive insoluble material layer 30 is developed. Next, an electrically conductive sacrificial layer 40 is formed on the opaque electrically conductive layer 20 by an electrolytic plating method, and an injection molding die 50 composed of an Ni electroforming plating layer is formed on the sacrificial layer 40 by an Ni electroforming plating method. Finally, the transparent substrate 10, opaque electrically conductive layer 20, photosensitive insoluble material layer 30 and sacrificial layer 40 are removed to obtain the injection molding die 50 of about <=100 μm having taper angles θ on the recessed parts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an injection mold used for an injection molding method, which is a kind of part manufacturing method, and more particularly to an injection mold for a fine part.

[0002]

2. Description of the Related Art A part manufacturing method called an injection molding method is generally used as a part manufacturing method. In this manufacturing method, a large number of parts are transfer-molded based on one set of injection molds, and therefore, it is important to form the base injection mold with high precision.

Conventionally, there are two types of methods for manufacturing an injection mold using a cutting method.

[0004] First, there is a method of directly cutting a rigid metal material. This method is the simplest method with few manufacturing steps, and is often used when accuracy and fine shape are not required.

Another method is used when a certain degree of accuracy is required. FIG. 6 shows a conventional method of manufacturing the injection mold. First, the original mold 60 is formed by a cutting method using a material that is easily cut, such as a plastic material (FIG. 6A). Since plastic materials have better workability than metal materials, there is an advantage that dimensional accuracy can be easily obtained.

Thereafter, a conductive layer 70 is formed on the original mold 60, and an injection mold 52 is formed on the conductive layer 70 by electroforming plating (FIG. 6B). Conductive layer 70
Is an electrode film for the electroforming plating method, so that 0.2 to 0.2.
A film thickness of about 5 μm is sufficient. Usually, the conductive layer 70 is formed by a vapor deposition method, a sputtering method, or the like.

Finally, the injection mold 52 is completed by removing the original mold 60 and the conductive layer 70 (FIG. 6).
(C)).

The above is the method of manufacturing an injection mold conventionally used. On the other hand, a method of forming a fine and highly accurate injection mold by combining a photolithography method and an electroforming plating method used in the field of LSI has been studied. The purpose of this study is to find a manufacturing method that can respond to recent miniaturization of components. However, in practice, it has not been possible to form a usable injection mold. Therefore, conventionally, the manufacturing method of the injection molding die actually used only requires the cutting work by using only the above two kinds of methods.

[0009]

SUMMARY OF THE INVENTION As mentioned above,
The conventional method of manufacturing an injection mold requires cutting. However, there are some shapes that cannot be completely processed by the cutting process, and particularly when the processing size is 100 μm or less, the processing often cannot be performed. Even if it could be processed, the processing accuracy was very poor and it was difficult to use it as a mold.

In the method for manufacturing an injection mold of the present invention, 10
Since it is possible to sufficiently process even a dimension of 0 μm or less, it is possible to manufacture an injection mold that could not be manufactured conventionally. That is, an object of the present invention is to provide an injection mold for a fine component.

[0011]

In order to solve the above-mentioned problems, a method of manufacturing an injection mold for fine parts according to the present invention provides a method for manufacturing an injection-molding die for fine parts on a transparent substrate on which an opaque conductive layer having a desired shape is formed. A step of coating the photosensitive insoluble material layer, and thereafter patterning the photosensitive insoluble material layer by exposing from the transparent substrate side through the opaque conductive layer,
A step of forming a sacrificial layer having a desired thickness by performing a plating process on the opaque conductive layer; and forming an electroformed plating layer by performing an electroformed plating process on the sacrificial layer; Dissolving the layer and the photosensitive insoluble material layer to remove the transparent substrate and the opaque conductive layer from the electroformed plating layer.

[0012]

FIG. 1 is a view showing a method of manufacturing an injection mold for fine parts according to the present invention. And FIG.
FIG. 3 is a view showing a method of forming an original mold serving as a base of an injection mold for fine parts according to the present invention. Hereinafter, the method of manufacturing the injection mold for microparts of the present invention will be described step by step.

First, in FIG. 2A, the opaque conductive layer 20 is patterned in a desired shape on the transparent substrate 10, and the opaque conductive layer 20 on the transparent substrate 10 is formed. Is coated with a photosensitive insoluble material layer 30.

In the present embodiment, a borosilicate glass substrate having a thickness of 0.4 mm is used as the transparent substrate 10, and an opaque conductive layer 20 made of gold (Au) having a thickness of 0.2 μm is formed thereon. Patterned. The opaque conductive layer 20 made of Au is patterned by a photolithography etching method after being formed by a sputtering method.

Further patterned opaque conductive layer 2
0 was coated with the photosensitive insoluble material layer 30. In this embodiment, a negative thick film resist (trade name: THB-30) manufactured by JSR Corporation is used as the photosensitive insoluble material layer 30. Further, a spin coating method was used as a coating method, and the coating was performed with a thickness of 110 μm by performing the coating twice under the condition of spin coating at a rotation speed of 1000 rpm for 10 seconds. In this embodiment, every time one spin coating is completed, prebaking is performed for 5 minutes on a hot plate at 100 ° C. to evaporate the solvent in THB-30.

Next, the photosensitive insoluble material layer 30 is
Exposure is performed from the other surface side where the 0 opaque conductive layer 20 is not formed (FIG. 2B). By performing the exposure in this manner, the patterned opaque conductive layer 20 serves as an exposure mask, and an exposed portion and an unexposed portion are generated in the photosensitive insoluble material layer 30. Such an exposure method is generally called a back exposure method.

In this embodiment, PEM-1000 manufactured by Union Optical Co., Ltd. was used as an exposure apparatus, and back exposure was performed under an exposure condition of 600 mJ / cm 2.

When the photosensitive insoluble material layer 30 having a thickness exceeding 100 μm is exposed by the back exposure method as in the present embodiment, a sufficient number of exposures are performed so that the exposure extends to the vicinity of the surface of the photosensitive insoluble material layer 30. Need quantity. Therefore, in the vicinity of the transparent substrate 10 of the photosensitive insoluble material layer 30, the exposure amount tends to be excessive. In such an excessive light exposure state, scattering of ultraviolet light due to the ultraviolet light diffraction phenomenon at the edge of the opaque conductive film 20 naturally increases. As a result, the transparent substrate 10 of the photosensitive insoluble material layer 30
In the vicinity, the exposure is slightly wider than the pattern width of the opaque conductive layer 20.

FIG. 1A shows a state in which the photosensitive insoluble material layer 30 exposed in FIG. 3B has been developed. The cross-sectional shape of the developed and patterned photosensitive insoluble material layer 30 has a bulging shape near the transparent substrate 10 due to the influence of the above-described ultraviolet light diffraction phenomenon. In the present embodiment, the height h from the surface of the opaque conductive layer 20 to the top of the bulge (hereinafter referred to as the bulge height) was 10 μm. The bulge height h naturally varies somewhat depending on the exposure conditions, but according to our experimental results, it is known that the bulge height h occurs between h = 5 and 20 μm.

In this embodiment, THB at 40 ° C.
Developing was performed for 10 minutes by a spray developing method using a -30 exclusive developer. Rinsing after development was performed by immersing the film in running water (pure water) at 20 ° C. for 1 minute.

A conductive sacrificial layer 40 having a desired thickness is formed by electrolytic plating on the opaque conductive layer 20 from which the photosensitive insoluble material layer 20 has been developed and removed.
Further, an injection mold 50 composed of an electroformed plating layer is formed on the sacrificial layer 40 by electroforming plating.
(B)). In this step, finally, the photosensitive insoluble material layer 30
Are completely covered by the injection mold 50.

In the present embodiment, copper (Cu), which is a material that is easily etched for forming the sacrificial layer 40, is selected as the plating material, and the sacrificial layer 40 is formed with a thickness of 10 μm. The thickness of 10 μm is a thickness set so as to match the bulging height h of the photosensitive insoluble material layer 30 in FIG. The most characteristic feature of the present invention is that the sacrifice layer 40 is formed. Further, it is effective that the thickness of the sacrifice layer 40 is equal to or larger than the height h of the sacrifice layer 40 to effectively achieve the present invention. It is important in doing.

Further, in the present embodiment, the injection molding die 50 formed of a Ni electroformed plating layer is formed by using a nickel (Ni) electroforming plating method for forming the injection molding die 50.
It was formed with a thickness of 0 μm. The bath composition of the Ni electroformed plating used was as follows. Pure water 5 L Nickel sulfamate 1650 g Nickel chloride 150 g Boric acid 225 g Sodium lauryl sulfate 5 g Further, electroforming plating conditions in the present embodiment were a bath temperature of 50 ° C., a current density of 2 A / dcm 2, and an electroforming time of 20 hours.

Finally, as shown in FIG. 1 (c), the transparent substrate 10, the opaque conductive layer 20, the photosensitive insoluble material layer 30, and the sacrificial layer 40 are removed, and an injection mold formed by electroforming plating. 50 is completed. In the injection mold 50 manufactured according to the present invention, a taper angle θ occurs in the concave portion. This is a transfer of the taper angle originally formed on the photosensitive insoluble material layer 30 at the time of FIG. The taper angle θ hardly changes at an angle of about 10 degrees. This taper angle of θ = 10 degrees is
This is a very good angle for releasing the molded product from the injection molded product. This is one of the features that the present invention is effective for the method of manufacturing an injection mold.

In this embodiment, first, the photosensitive insoluble material layer 30 made of THB-30 is dissolved by a stripping solution exclusive for THB-30, and the sacrificial layer 40 made of Cu is dissolved by a nitric acid-based etchant. By doing so, the opaque conductive layer 20 made of Au and the transparent substrate 10 made of glass could be removed from the injection mold 50 without difficulty.

As described above, the present invention is characterized in that a sacrificial layer is formed on an opaque conductive layer.
The reason will be described below. FIG. 4 is a diagram showing a case where an injection mold is formed without forming a sacrificial layer. FIG.
After the state of (a), an injection mold 50b is formed directly on the opaque conductive layer 20 by electroforming plating (FIG. 4).
(A)).

Thereafter, the transparent substrate 10, the opaque conductive layer 2
The injection mold 50b is completed by removing the O and the photosensitive insoluble material layer 30 (FIG. 4B). The electroforming plating method has very good transferability, and the injection mold 50 manufactured by this method is transfer-molded with the bulge shape of the photosensitive insoluble material layer 30 as shown in FIG. 4B. I will. In the injection molding method, it is necessary to inject a molding material into an injection mold and then release the solidified molded product. It is clear that mold release cannot be performed with a shape having a narrow opening as shown in FIG. 4B, and a shape that cannot function as an injection molding die is formed when a sacrificial layer is not formed as described above. By forming the sacrificial layer as in the present invention, the shape in which the opening is narrowed can be eliminated, and as a result, a shape that can function as an injection mold can be formed.

Next, as an example of use of the injection mold manufactured according to the present invention, a case of manufacturing an ink jet head part will be described. First, after a brief description of the entire ink jet head, the production using the present invention will be described.

FIG. 5 is a configuration diagram of a general ink jet head. The main components are a liquid chamber component 100, a nozzle plate 200 constituting a nozzle 210 serving as a discharge hole, a diaphragm 300 serving as a diaphragm, a piezoelectric element 400 for generating a driving force, and a base 500. . The inkjet head is completed by joining these components.

The liquid chamber component 100 has a large number of side walls 1 at equal intervals.
The space formed by the side wall 110 is called a liquid chamber 120. The liquid chamber 120 serves as a pressurizing chamber for pressurizing the ink,
It is aligned and joined so as to communicate with zero. As a result, the ink pressurized in the liquid chamber 120 is discharged from the nozzle 210
Will be ejected. The interval between the nozzles 210 and the interval between the liquid chambers 110 must be the same. Therefore, high dimensional accuracy is required for each part. Also, the narrower the interval, the higher the printing density,
It is also required to increase the density of these intervals.

In recent years, an ink jet head capable of high density printing has been demanded. This aims at improving the printing quality. For this purpose, it is necessary to accurately form a liquid chamber component having a narrow liquid chamber interval.

FIG. 3 is a schematic view of a case where a liquid chamber component is formed using an injection mold according to the present invention. Injection mold 50
Are formed under the same conditions as those described in the present embodiment. The height of the convex part of the injection mold 50 is 100 μm, the width of the bottom part (the upper part in the figure) of the convex part is 40 μm, and the interval between the convex parts is 70 μm.

The injection mold 50 manufactured according to the present invention
The liquid chamber component 100b can be manufactured by injection molding with the injection molding die 51 that is paired with the injection molding die 51. In order to transfer the shape of the injection mold 50 with high precision, the liquid chamber component 100b has side walls 110 having a height of 100 μm at intervals of 70 μm.
b will be formed. The liquid chambers 120b formed by the side walls 110b are also spaced at 70 μm. This 70
The interval of μm is 360 dots /
It means inches (dpi), meaning that high-density printing is possible. As described above, by using the injection mold according to the present invention, it is also possible to manufacture components of an ink jet head capable of high-density printing.

[0034]

According to the method of manufacturing an injection mold of the present invention, a fine injection mold having a size and shape of 100 μm or less, which could not be manufactured conventionally, can be manufactured. That is, an object of the present invention is to provide an injection mold for a fine component.

[Brief description of the drawings]

FIG. 1 is a view showing a method for manufacturing an injection mold for fine parts according to the present invention.

FIG. 2 is a view showing a method of forming an original mold serving as a base of an injection mold for fine parts according to the present invention.

FIG. 3 is a schematic view of a manufacturing process of an inkjet head component using the injection molding die for fine components according to the present invention.

FIG. 4 is a schematic diagram when the process proceeds to an electroforming plating process without forming a sacrificial layer.

FIG. 5 is a configuration diagram of a general inkjet head.

FIG. 6 is a view showing a conventional method of manufacturing an injection mold.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 transparent substrate 20 opaque conductive layer 30 photosensitive insoluble material layer 40 sacrifice layer 50, 50b, 51, 52 injection mold 60 original mold 70 conductive layer 100, 100b liquid chamber component 110, 110b side wall 120, 120b liquid chamber 200 nozzle Plate 210 Nozzle 300 Diaphragm 400 Piezoelectric element 500 Base

Claims (1)

[Claims] 1. A method of manufacturing an injection mold having a large number of fine side walls manufactured by an electroforming method, wherein an opaque conductive layer having a desired shape for forming the side walls is formed. Patterning the photosensitive insoluble material layer by coating a photosensitive insoluble material layer on a transparent substrate, and then exposing the photosensitive insoluble material layer from the transparent substrate side through the opaque conductive layer; By performing a plating process on the layer to form a sacrificial layer having a desired thickness, and by performing an electroforming plating process on the sacrificial layer,
Forming an electroformed plating layer; and dissolving the sacrificial layer and the photosensitive insoluble material layer to remove the transparent substrate and the opaque conductive layer from the electroformed plating layer. A method for producing an injection mold, characterized in that: