JP7705289B2 - Electroforming mold and method of manufacturing electroformed product using electroforming mold - Google Patents

Description

The present invention relates to an electroforming mold and a method for manufacturing an electroformed product using the electroforming mold.

For example, minute structures such as watch parts are manufactured by electroforming (a method for manufacturing, repairing, or replicating metal products using electroplating; hereafter referred to as electroforming). In this context, the LIGA (Lithographie, Galvanoformung, Abformung) method has been widely applied in recent years. This method involves forming a photoresist layer on a substrate, forming a pattern of soluble and insoluble parts in the photoresist layer, producing an electroforming mold, and manufacturing fine, high-precision electroformed products.

Depending on the shape of the electroformed product, multiple resist layers may be formed. In this case, if there is a step between layers, an intermediate conductive layer can be formed in the step to increase the growth rate of the electroformed layer above the step (see, for example, Patent Document 1).

Patent No. 4840756

In electroforming, and particularly in the LIGA method, a photoresist layer is used as the mold for the electroformed product (electroforming mold), but in order to finally remove the electroformed product from the electroforming mold, the photoresist layer, which is the electroforming mold, must be dissolved. In other words, the electroforming mold must be recreated every time an electroformed product is manufactured.

The present invention has been made in consideration of the above circumstances, and aims to provide an electroforming mold that can be reused repeatedly and a method for manufacturing electroformed products using the electroforming mold.

The first aspect of the present invention is an electroforming mold comprising a conductive substrate, an electroforming mold base disposed on the substrate, a sacrificial layer covering at least the surfaces of the substrate and the electroforming mold base that face a cavity formed by the substrate and the electroforming mold base in which an electroformed product is to be formed, the surfaces being in contact with the substrate, and an insulating resist layer covering the sacrificial layer except for at least a portion of the portion that corresponds to the bottom surface of the cavity.

The second aspect of the present invention is a method for manufacturing an electroformed product using an electroformed mold, which uses the electroformed mold according to the present invention to grow plating in the hollow portion by electroplating, and after the plating has grown to fill the hollow portion, at least the sacrificial layer out of the sacrificial layer and the resist layer is dissolved without dissolving the electroformed mold base, and the electroformed product formed by plating and filling the hollow portion is separated from the electroformed mold.

The electroforming mold according to the present invention can be reused repeatedly. Furthermore, according to the method for manufacturing electroformed products using the electroforming mold according to the present invention, the electroforming mold can be reused repeatedly to manufacture electroformed products.

FIG. 1 is a cross-sectional view (part 1) showing a schematic flow of an example of a method (manufacturing method) for manufacturing an electroforming mold, which is a mold for manufacturing an electroformed product. 1 is a cross-sectional view (part 2) showing a schematic diagram of an example of a method (manufacturing method) for manufacturing an electroforming mold, which is a mold for manufacturing an electroformed product. 1 is a cross-sectional view (part 3) showing a schematic flow of an example of a method (manufacturing method) for manufacturing an electroforming mold, which is a mold for manufacturing an electroformed product. 4 is a cross-sectional view (part 4) showing a schematic flow of an example of a method (manufacturing method) for manufacturing an electroforming mold, which is a mold for manufacturing an electroformed product. 5 is a cross-sectional view (part 5) showing a schematic flow of an example of a method (manufacturing method) for manufacturing an electroforming mold, which is a mold for manufacturing an electroformed product. 6 is a cross-sectional view (part 6) showing a schematic flow of an example of a method (manufacturing method) for manufacturing an electroforming mold, which is a mold for manufacturing an electroformed product. 7 is a cross-sectional view showing a schematic flow of an example of a method for manufacturing an electroformed product using the electroforming mold shown in FIG. 6. FIG. 1 is a cross-sectional view (part 1) showing a schematic flow of an example of a manufacturing method for an electroforming mold in which the portion interposed between the electroforming mold base and the electroformed product is formed of a resist layer that functions as a non-conductive sacrificial layer, and shows the steps following the manufacturing method flow shown in FIGS. 1 to 4. This is a cross-sectional view (part 2) showing a schematic flow of one example of a manufacturing method for an electroforming mold in which the portion interposed between the electroforming mold base and the electroformed product is formed of a resist layer that functions as a non-conductive sacrificial layer. 10A to 10C are cross-sectional views showing a schematic flow of an example of a method for manufacturing an electroformed product using the electroforming mold shown in FIG.

The following describes an embodiment of the electroforming mold according to the present invention and a method for manufacturing an electroformed product using the electroforming mold, with reference to the drawings.

<Embodiment 1>
Figures 1 to 6 are cross-sectional views (Nos. 1 to 6) that show a schematic flow (indicated by arrows) of one example of a method (manufacturing method) for manufacturing an electroformed mold 80, which is a mold for manufacturing an electroformed product 70, and the steps are in the order of Figure 1 followed by Figure 2, Figure 2 followed by Figure 3, Figure 3 followed by Figure 4, Figure 4 followed by Figure 5, and Figure 5 followed by Figure 6. Figure 7 is a cross-sectional view that shows a schematic flow (indicated by arrows) of one example of a method for manufacturing an electroformed product 70 using the electroformed mold 80 manufactured by the steps of Figures 1 to 6.

The electroforming mold 80 is one embodiment of the electroforming mold according to the present invention, and the manufacturing method of the electroformed product 70 using this electroforming mold 80 is one embodiment of the manufacturing method of the electroformed product according to the present invention.

(Electroforming mold)
First, an example of a manufacturing method for the electroforming mold 80 will be described with reference to Figures 1 to 6. Note that the electroforming mold 80 is not limited to one manufactured by the manufacturing method shown in Figures 1 to 6, and may be one manufactured by another manufacturing method.

First, as shown in FIG. 1, a photoresist layer 20 is laminated on a substrate 10. The substrate 10 may have a conductive substrate body 11, or may have a conductive conductive film (conductive layer) 12 formed on the surface 11a of the substrate body 11 on which the photoresist layer 20 is laminated, in the case where the substrate body 11 is not conductive, for example, silicon. When the substrate body 11 is conductive, the conductive film 12 does not need to be formed (laminated) on the substrate body 11, in which case the substrate body 11 corresponds to a conductive substrate 10.

In this embodiment, the conductive layer 12 is formed, for example, of a laminated film of titanium (Ti) and nickel (Ni) (with the titanium on the substrate body 11 side), but the conductive layer 12 is not limited to this material and may be any material that is conductive. Note that when the substrate body 11 is conductive, the conductive layer 12 may not be provided.

The photoresist layer 20 may be a positive resist in which the parts irradiated with ultraviolet light (ultraviolet light) are soluble and the parts not irradiated are insoluble, or a negative resist in which the parts irradiated with ultraviolet light are insoluble and the parts not irradiated are soluble. The photoresist layer 20 in the manufacturing method of the electroformed product 70 shown in Figure 1 will be described on the assumption that it is a negative resist.

Next, a photomask 90 is placed on the surface (top surface as shown) of the photoresist layer 20, and ultraviolet light L is irradiated onto the photoresist layer 20 from above through the photomask 90.

The photomask 90 has a pattern consisting of light-transmitting sections 92 that transmit ultraviolet light L and light-shielding sections 91 that do not transmit ultraviolet light L. The pattern is formed to correspond to the contour shapes of the electroforming mold 80 and the electroformed product 70.

When ultraviolet light L is irradiated through the photomask 90, the portions of the photoresist layer 20 below the light-transmitting portions 92 become insoluble portions 22 due to the ultraviolet light L being transmitted therethrough and being irradiated with the ultraviolet light L, and remain even after development processing. On the other hand, the portions of the photoresist layer 20 below the light-shielding portions 91 become soluble portions 21 due to the ultraviolet light L being blocked and not being irradiated with the ultraviolet light L, and are removed by development processing as shown in FIG. 2.

In this way, the light-shielding portions 91 of the photomask 90 form soluble portions 21 in the photoresist layer 20, and the light-transmitting portions 92 form insoluble portions 22 in the photoresist layer 20. In contrast, when the photoresist layer 20 is a positive resist, the light-shielding portions 91 form insoluble portions in the photoresist layer 20, and the light-transmitting portions 92 form soluble portions in the photoresist layer 20.

As shown in FIG. 2, when the soluble portion 21 is removed by the development process, the portion where the soluble portion 21 was present becomes a cavity portion 23, and in this cavity portion 23, the substrate 10 is exposed, and a pattern of this cavity portion 23 and the insoluble portion 22 is formed.

Then, in the electroplating process, a metal such as nickel is precipitated and grown from the substrate 10 in the cavity 23, forming a first layer electroforming mold base 31 of a metal such as nickel that corresponds to the contour shape of the cavity 23. The surface of the first layer electroforming mold base 31 (the top surface shown in the figure) may be ground and polished flat.

Then, the insoluble portion 22 of the photoresist layer 20 is removed by a separate process, and the portion between the electroforming mold base portions 31 of the first layer where the insoluble portion 22 was present becomes a cavity portion 33.

Next, a photoresist layer 25 is formed to cover the first electroforming mold base 31, including the cavities 33 between the first electroforming mold bases 31. The photoresist layer 25 is made of the same material as the photoresist layer 20, but may be made of a different material or may be a positive photoresist layer.

Next, a photomask 95 is placed on the surface (top surface as shown) of the photoresist layer 25, and ultraviolet light L is irradiated onto the photoresist layer 20 from above through the photomask 95.

The photomask 95 has a pattern made up of light-transmitting sections 97 that transmit the ultraviolet light L and light-shielding sections 96 that do not transmit the ultraviolet light L. The pattern is formed to correspond to the contour shapes of the electroforming mold 80 and the electroformed product 70.

When ultraviolet light L is irradiated through the photomask 95, the portion of the photoresist layer 25 below the light-transmitting portion 97 becomes an insoluble portion 27 due to being irradiated with ultraviolet light L through the light-transmitting portion 97, and remains even after development processing. On the other hand, the portion of the photoresist layer 25 below the light-shielding portion 96 becomes a soluble portion 26 due to being shielded from ultraviolet light L and not being irradiated with ultraviolet light L, and is removed by development processing as shown in FIG. 3.

When the soluble portion 26 is removed by the development process, the area where the soluble portion 26 was present becomes a cavity portion 28 surrounded by the insoluble portion 27 and the substrate 10, and in this cavity portion 28, the first layer electroforming mold base portion 31 is exposed, and a pattern of this cavity portion 28 and the insoluble portion 27 is formed.

Then, in the cavity 28, a metal such as nickel grows from the first-layer electroforming mold base 31 connected to the conductive layer 12 of the substrate 10 through the electroplating process, and as shown in FIG. 4, a second-layer electroforming mold base 36 made of a metal such as nickel is formed that corresponds to the contour shape of the cavity 28, forming an electroforming mold that is stacked in two layers in the thickness direction. The surface of the second-layer electroforming mold base 36 (the top surface shown in the figure) may be ground and polished flat.

Then, the insoluble portion 27 of the photoresist layer 25 is removed by a separate process, and the portions between the electroforming mold bases 31 of the first layer and between the electroforming mold bases 36 of the second layer where the insoluble portion 27 was present become hollow portions 33 surrounded by the electroforming mold bases 31, 36 and the substrate 10.

The second-layer electroforming mold base 36 is stacked on the first-layer electroforming mold base 31 in the thickness direction of the substrate 10, and is smaller than the first-layer electroforming mold base 31. Therefore, at the boundary between the first-layer electroforming mold base 31 and the second-layer electroforming mold base 36, a step 34 is formed where the first-layer electroforming mold base 31 protrudes from the second-layer electroforming mold base 36.

5, the surfaces of the first electroforming mold base 31, the second electroforming mold base 36, and the substrate (including the side surfaces) that face the cavity 33 in which the electroformed product 70 is to be formed are covered with a sacrificial layer 50. The sacrificial layer 50 is a layer that will later be dissolved in place of the electroforming mold bases 31 and 36 to separate the electroformed product 70 from the electroforming mold 80, and is formed by sputtering, for example, of copper (Cu) (thickness, for example, 2 μm). A titanium layer may be formed between the copper sacrificial layer 50 and the surface that faces the cavity 33 in which the electroformed product 70 is to be formed.

The sacrificial layer 50 is formed of a conductive material because it serves as the starting point for plating to form the electroformed product 70. The sacrificial layer 50 is not limited to copper. The sacrificial layer 50 is later dissolved in place of the electroformed mold bases 31, 36, so it must be formed of a material that is dissolved by a different chemical than the electroformed mold bases 31, 36. Therefore, the sacrificial layer 50 is formed of a different material than the electroformed mold bases 31, 36.

Although not shown in the present embodiment, a copper layer of uniform thickness (e.g., 2 μm) may be formed on the sacrificial layer 50 by electroless plating. By forming a copper layer, when the sacrificial layer 50 is formed by electroless plating instead of sputtering, the thickness of the sacrificial layer 50 can be made more uniform, and the dimensional accuracy of the electroformed product 70 can be improved.

Next, using a metal mask (stencil mask) 98 in which openings 99 are formed in the portions of the sacrificial layer 50 that correspond to the starting points of plating (bottom surface 33a in contact with conductive layer 12 of substrate 10), particles 61 (e.g., ferrite particles with a size of about 10 μm) are placed on bottom surface 33a, which is the starting point of plating, of the sacrificial layer 50. Specifically, by immersing in a solution 60 in which the particles 61 are dispersed, the particles 61 settle from the openings 99 to the bottom surface 33a, and the particles 61 can be placed on the bottom surface 33a.

Next, the sacrificial layer 50 is covered with a resist layer 55. Specifically, a resist layer 55 of silicon (Si) is formed on the surface of the sacrificial layer 50 by sputtering. A titanium layer may be formed between the sacrificial layer 50 and the resist layer 55 to increase the adhesion between the sacrificial layer 50 and the resist layer 55.

Here, at the bottom surface 33a where the particles 61 are present, the adhesion between the sacrificial layer 50 and the resist layer 55 laminated on the sacrificial layer 50 is lower than in the other areas. The resist layer 55 is non-conductive.

Therefore, as shown in FIG. 6, when ultrasonic cleaning is performed on the resist layer 55, the portion of the resist layer 55 that is layered on the bottom surface 33a of the cavity 33 and has relatively low adhesion to the sacrificial layer 50 due to the presence of particles 61 is removed, and the sacrificial layer 50 is exposed.

In other words, the hollow portion 33 in which the electroformed product 70 is formed has the conductive sacrificial layer 50 exposed only in the portion corresponding to the bottom surface 33a of the hollow portion 33, and the portion of the sacrificial layer 50 other than the bottom surface 33a is covered with the non-conductive resist layer 55. Therefore, in the manufacturing method in which the electroformed product 70 is formed in the hollow portion 33 by electroplating, plating can be grown only from the sacrificial layer 50 corresponding to the bottom surface 33a. Note that the portion of the sacrificial layer 50 exposed in the portion corresponding to the bottom surface 33a by removing the resist layer 55 may be a part or the whole of the portion corresponding to the bottom surface 33a.

The resist layer 55 may also be removed from a portion of the resist layer 55 that is adjacent to the portion corresponding to the bottom surface 33a of the cavity 33 and corresponds to the side surface 33b of the cavity 33. In other words, the resist layer 55 may cover the sacrificial layer 50 excluding the portion corresponding to the bottom surface 33a of the cavity 33 and a portion corresponding to the side surface 55b.

As a method for removing the resist layer 55 on the bottom surface 33a, instead of using the particles 61 described above, an aluminum film may be formed only on the bottom surface 33a by vacuum deposition.

Since the resist layer 55 has defects such as pinholes, the liquid used to remove the aluminum film dissolves the aluminum through the defects, peeling off the resist layer 55 (lift-off), and the resist layer 55 on the bottom surface 33a can be removed.

As an alternative method, the resist layer 55 on the bottom surface 33a may be removed by vacuum deposition from an oblique direction or by irradiation with laser light.

Next, using a mask 65 with an opening 67 formed corresponding to the area of the step 34 formed at the boundary between the first layer electroforming mold base 31 and the second layer electroforming mold base 36, an intermediate conductive layer 45 is formed on the step 34 by vacuum deposition. The intermediate conductive layer 45 is made of, for example, the same nickel as the conductive layer 12 (or nickel with titanium interposed therebetween).

The electroforming mold 80 of embodiment 1 shown in Figure 6 is manufactured by the above manufacturing method. Here, the electroforming mold 80 has a conductive substrate 10, a first layer electroforming mold base 31, a second layer electroforming mold base 36, a sacrificial layer 50 that covers the surface of the substrate 10 and the surfaces of the electroforming mold bases 31 and 36 that face the cavity 33 that forms the electroformed product 70, a resist layer 55 that covers the sacrificial layer 50 except for the bottom surface 33a of the cavity 33, and an intermediate conductive layer 45 arranged on the step portion 34.

(Method of manufacturing electroformed products)
7 is a cross-sectional view showing a schematic flow of an example of a manufacturing method of an electroformed product 70 using the electroforming mold 80. Next, an example of a manufacturing method of an electroformed product 70 using this electroforming mold 80 will be described with reference to FIG. When electroplating, for example, nickel, is performed using the electroforming mold 80, an electroformed product 70 of nickel grows from the sacrificial layer 50 exposed on the bottom surface 33a. When the electroformed product 70 fills the cavity 33 of the first layer of the electroforming mold base 31, the grown electroformed product 70 comes into contact with the intermediate conductive layer 45 of the step portion 34, and electricity flows through the intermediate conductive layer 45.

As a result, in the cavity 33 of the second layer electroforming mold base 36, plating grows from the electroformed product 70 that filled the cavity 33 of the first layer and the intermediate conductive layer 45, forming an electroformed product 70 that fills the cavity 33 of the second layer.

In this way, the plating that fills the cavity 33 of the second layer grows not only from the electroformed product 70 that fills the cavity 33 of the first layer, but also from the intermediate conductive layer 45, so the time required to fill the cavity 33 of the second layer with plating can be shortened compared to an electroformed mold in which the intermediate conductive layer 45 is not disposed.

Next, after the electroformed product 70 has been formed up to the second layer cavity 33, the electroformed product 70 with the resist layer 55, sacrificial layer 50, and second layer cavity 33 filled is ground and polished flat so that the top surface of the second layer electroformed mold base 36 is exposed. This exposes the sacrificial layer 50, which is the boundary between the electroformed product 70 and the electroformed mold base 36 and electroformed mold base 31, on the top surface. Ideally, by completing the grinding and polishing to the extent that the sacrificial layer 50 is exposed, wear on the electroformed mold base 36 can be suppressed.

Then, the electroformed product 70 is separated from the electroformed mold base 36 and the electroformed mold base 31 by dissolving the sacrificial layer 50 exposed on the upper surface. At this time, the chemical used to dissolve the sacrificial layer 50 is selected as a chemical that does not affect the electroformed mold bases 31 and 36, so the electroformed mold bases 31 and 36 are not dissolved and remain as the electroformed mold bases 31 and 36 shown in FIG. 4.

Therefore, the electroforming mold bases 31 and 36 in the state shown in FIG. 4 can be reused to form the electroforming mold 80 in the steps shown in FIGS. 5 and 6, allowing the electroforming mold bases 31 and 36 to be used repeatedly.

The electroformed product 70 separated from the electroforming mold 80 has a resist layer 55 and an intermediate conductive layer 45 remaining on the surface. If this does not interfere with the electroformed product 70, the resist layer 55 and the intermediate conductive layer 45 may be left on the electroformed product 70. On the other hand, if the resist layer 55 and the intermediate conductive layer 45 are not required, a separate process may be added to the electroformed product 70 to remove the resist layer 55 and the intermediate conductive layer 45.

As described above in detail, the electroforming mold 80 of embodiment 1 can be reused repeatedly, rather than being used up each time an electroformed product 70 is manufactured. Furthermore, according to the method for manufacturing an electroformed product 70 using the electroforming mold 80 of this embodiment, the electroformed product 70 can be manufactured by repeatedly using the electroforming mold 80.

Therefore, the manufacturing method of the electroformed product 70 using the electroformed mold 80 of this embodiment can reduce the manufacturing cost of the electroformed product 70 compared to a manufacturing method in which an electroformed mold is used up each time an electroformed product 70 is manufactured.

<Embodiment 2>
The electroforming mold 80 of the above-mentioned embodiment 1 has a conductive sacrificial layer 50 formed on the entire surface of the substrate 10 and the electroforming mold bases 31, 36, that faces the cavity 33 in which the electroformed product 70 is formed, which is formed by the substrate 10 and the electroforming mold bases 31, 36.However, the electroforming mold of the present invention is not limited to having a conductive sacrificial layer 50 formed on the entire surface facing the cavity 33.

In other words, the conductive sacrificial layer 50 only needs to cover at least a portion (a portion of the bottom surface 33a or the entire bottom surface 33a) of the surface facing the cavity 33 in which the electroformed product 70 is formed, that is in contact with the substrate 10 (the bottom surface 33a of the cavity 33).

In other words, the conductive sacrificial layer 50 is the starting point for the growth of the electroformed product 70, and therefore must be in contact with the substrate 10, and must therefore be formed as part of the bottom surface 33a of the cavity 33 and in contact with the substrate 10.

On the other hand, the sacrificial layer 50 itself needs to dissolve to separate the electroforming mold bases 31, 36 from the electroformed product 70, but the portion between the electroforming mold bases 31, 36 and the electroformed product 70 does not need to be conductive. In other words, the portion between the electroforming mold bases 31, 36 and the electroformed product 70 is not the sacrificial layer 50, which is conductive, but rather it only needs to dissolve regardless of whether it is conductive and perform the function of separating the electroforming mold bases 31, 36 from the electroformed product 70.

Therefore, the conductive sacrificial layer 50 only needs to cover at least a portion of the bottom surface 33a of the cavity 33 (a portion of the bottom surface 33a or the entire bottom surface 33a), and the portion of the surface facing the cavity 33 in which the electroformed product 70 is formed, which is between the electroforming mold base 31, 36 and the electroformed product 70, except for the portion of the bottom surface 33a on which the conductive sacrificial layer 50 is disposed, may be formed of a non-conductive sacrificial layer.

Figures 8 and 9 are cross-sectional views showing a schematic flow of an example of a method for manufacturing an electroforming mold 180 in which the portion interposed between the electroforming mold base 31, 36 and the electroformed product 70 is formed of a resist layer 55 that functions as a non-conductive sacrificial layer, and show steps following the flow of the manufacturing method shown in Figures 1 to 4. Also, Figure 10 is a cross-sectional view showing a schematic flow of an example of a method for manufacturing an electroformed product 70 using the electroforming mold 180 shown in Figure 9.

The electroforming mold 180 of this embodiment is manufactured by the manufacturing method shown in Figures 1 to 4, in which electroforming mold bases 31, 36 are formed on a substrate 10. As shown in Figure 8, the first layer electroforming mold base 31, the second layer electroforming mold base 36, and the surface of the substrate (including the side surfaces) that face the cavity 33 in which the electroformed product 70 is formed are coated with an insulating resist layer 55 by a spray coating method. The spray coating method allows the resist to be applied thinly and uniformly to match the unevenness of the surface of the object to be coated.

The resist layer 55 is dissolved together with the sacrificial layer 50 that will be formed later. Therefore, the resist layer 55 functions in the same manner as the sacrificial layer 50 in embodiment 1. The resist that forms the resist layer 55 is, for example, a positive resist. Positive resist has higher solubility than negative resist, and is therefore easier to use than negative resist when used as a sacrificial layer that will be dissolved later.

Next, a photomask 195 is placed, and the resist layer 55 is exposed from above through the photomask 195. The photomask 195 has a transparent portion 196 formed therein that transmits ultraviolet light L. The transparent portion 196 is formed corresponding to the bottom surface 33a of the cavity 33, and the resist layer 55 on the bottom surface 33a exposed through the transparent portion 196 is removed by exposure to ultraviolet light L, exposing the substrate 10 at the bottom surface 33a.

9, a mask 65 having an opening 67 corresponding to the area of the step 34 formed at the boundary between the first-layer electroforming mold base 31 and the second-layer electroforming mold base 36 is used to form an intermediate conductive layer 45 on the step 34 by vacuum deposition. The intermediate conductive layer 45 is made of, for example, the same nickel as the conductive layer 12 (or nickel with titanium interposed therebetween).

Next, an electroplating process is performed to form a sacrificial layer 50, for example of copper, on the substrate 10 exposed on the bottom surface 33a of the cavity 33.

The electroforming mold 180 of the second embodiment shown in Fig. 9 is manufactured by the manufacturing method described above. Here, the electroforming mold 180 includes a conductive substrate 10, a first-layer electroforming mold base 31, a second-layer electroforming mold base 36, and, among the surfaces of the substrate 10 and the electroforming mold bases 31 and 36 that face a cavity 33 forming the electroformed product 70, the surface that contacts the substrate 10 (bottom surface 33a of cavity 33) is covered with a conductive sacrificial layer 50 .

On the other hand, the electroforming mold 180 is formed of a non-conductive insulating resist layer 55 in the portion between the electroforming mold base 31, 36 and the electroformed product 70. This resist layer 55 dissolves together with the sacrificial layer 50 during the manufacturing process of the electroformed product 70, and functions as a sacrificial layer.

(Method of manufacturing electroformed products)
Next, an example of a manufacturing method of the electroformed product 70 using this electroforming mold 180 will be described with reference to Fig. 10. When electroplating, for example, nickel, is performed using the electroforming mold 180, the nickel electroformed product 70 grows from the sacrificial layer 50 formed on the bottom surface 33a. When the electroformed product 70 fills the cavity 33 of the first layer of the electroforming mold base 31, the grown electroformed product 70 comes into contact with the intermediate conductive layer 45 of the step portion 34, and electricity flows through the intermediate conductive layer 45.

As a result, in the cavity 33 of the second layer electroforming mold base 36, plating grows from the electroformed product 70 that filled the cavity 33 of the first layer and the intermediate conductive layer 45, forming an electroformed product 70 that fills the cavity 33 of the second layer.

In this way, the plating that fills the cavity 33 of the second layer grows not only from the electroformed product 70 that fills the cavity 33 of the first layer, but also from the intermediate conductive layer 45, so the time required to fill the cavity 33 of the second layer with plating can be shortened compared to an electroformed mold in which the intermediate conductive layer 45 is not disposed.

Next, after the electroformed product 70 has been formed up to the second-layer cavity 33, the electroformed product 70 with the resist layer 55 and the second-layer cavity 33 filled is ground and polished flat so that the top surface of the second-layer electroformed mold base 36 is exposed. This exposes the resist sacrificial layer 50, which functions as a sacrificial layer and is the boundary between the electroformed product 70 and the electroformed mold base 36 and electroformed mold base 31, on the top surface.

Then, the resist layer 55 exposed on the upper surface is dissolved, and further, the sacrificial layer 50 in contact with the substrate 10 is dissolved, thereby separating the electroformed product 70 from the electroformed mold base 36 and the electroformed mold base 31. At this time, the chemicals used to dissolve the resist layer and the chemicals used to dissolve the sacrificial layer 50 are selected as chemicals that do not affect the electroformed mold bases 31, 36, so the electroformed mold bases 31, 36 are not dissolved, and remain as the electroformed mold bases 31, 36 shown in FIG. 4.

Therefore, the electroforming mold bases 31 and 36 in the state shown in FIG. 4 can be reused to form the electroforming mold 180 in the steps shown in FIGS. 8 and 9, allowing the electroforming mold bases 31 and 36 to be used repeatedly.

The electroformed product 70 separated from the electroforming mold 180 has the intermediate conductive layer 45 remaining on its surface. If this does not interfere with the electroformed product 70, the intermediate conductive layer 45 may be left on the electroformed product 70. On the other hand, if the intermediate conductive layer 45 is not required, a separate process may be added to the electroformed product 70 to remove the intermediate conductive layer 45.

As described above in detail, the electroforming mold 180 of embodiment 2 can be reused repeatedly, rather than being used up each time an electroformed product 70 is manufactured. Furthermore, according to the method for manufacturing an electroformed product 70 using the electroforming mold 180 of this embodiment, the electroformed product 70 can be manufactured by repeatedly using the electroforming mold 180.

Therefore, the manufacturing method of the electroformed product 70 using the electroformed mold 80 of this embodiment can reduce the manufacturing cost of the electroformed product 70 compared to a manufacturing method in which an electroformed mold is used up each time an electroformed product 70 is manufactured.

The electroforming mold 80 in each of the above-mentioned embodiments is manufactured by the steps shown in Figures 1 to 6, or by the steps shown in Figures 1 to 4 and Figures 8 to 9, but the electroforming mold according to the present invention is not limited to those manufactured by the manufacturing method of each embodiment.

In other words, the electroforming mold of the present invention may be manufactured by any manufacturing method as long as it comprises a conductive substrate, an electroforming mold base disposed on the substrate, a conductive sacrificial layer covering at least the substrate surface (bottom surface of the cavity) of the substrate surface and the electroforming mold base surface that faces the cavity, and a resist layer covering the sacrificial layer except for the portion that corresponds to the bottom surface of the cavity.

The electroforming mold 80 in each embodiment is a two-layer electroforming mold, but the electroforming mold according to the present invention is not limited to two layers, and may be a one-layer mold or three or more layers.

The electroforming mold 80 in each embodiment is a two-layer electroforming mold, and therefore has an intermediate conductive layer 45 at the step 34 that is the boundary between the first layer electroforming mold base 31 and the second layer electroforming mold base 36, but an electroforming mold having only a single layer electroforming mold base 31 does not need to have an intermediate conductive layer.

In each embodiment, the electroforming mold 80 has the first layer electroforming mold base 31 and the second layer electroforming mold base 36 formed from metal, but the electroforming mold 80 only needs to have the bottom surface of the cavity 33 (part of the surface of the substrate) that forms the electroformed product 70 covered with a sacrificial layer, and the electroforming mold bases 31 and 36 do not necessarily have to be formed from metal.

Therefore, the electroforming mold bases 31, 36 may be made of resin. Note that the electroforming mold 80 in which the electroforming mold bases 31, 36 are made of resin must be formed using a microfabrication technique other than electroplating, because the resin electroforming mold bases 31, 36 cannot be formed by an electroplating process. In addition, the electroforming mold 80 in which the electroforming mold bases 31, 36 are made of resin may be formed using a pattern using the photoresist described above.

In each embodiment of the electroforming mold 80, plating can be grown only from the sacrificial layer 50 on the exposed bottom surface 33a, so plating growth in the second layer cavity 33 begins after plating growth in the first layer cavity 33, which is narrower than the second layer cavity 33, is completed.

Therefore, if an electroforming mold is used in which the exposed portion of the sacrificial layer 50 is not limited to only the bottom surface 33a by the resist layer 55, plating will grow faster in the second layer cavity 33, which is wider than the first layer cavity 33, than in the first layer cavity 33. In this case, the second layer cavity 33 will be filled with plating before the first layer cavity 33 is completely filled with plating, and there is a possibility that a cavity will remain in the first layer of the electroformed product 70.

In each embodiment, the electroforming mold 80 is exposed to the cavity 33 and limits the sacrificial layer 50 to only the bottom surface 33a, so plating can be grown from the cavity 33 in the first layer, preventing cavities from remaining in the first layer of the electroformed product 70.

In each embodiment of the electroforming mold 80, the sacrificial layer 50 is formed from a material different from that of the electroforming mold bases 31 and 36. However, if it is possible to dissolve only the sacrificial layer 50 without dissolving the electroforming mold bases 31 and 36, the sacrificial layer 50 may be formed from the same material as the electroforming mold bases 31 and 36.

10: Substrate 31, 36: Electroforming mold base 33: Cavity 33a: Bottom surface 50: Sacrificial layer 55: Resist layer 70: Electroformed product 80: Electroforming mold

Claims (7)

A conductive substrate;
an electroforming mold base disposed on the substrate;
a conductive sacrificial layer covering at least the surface of the substrate that faces a cavity formed by the substrate and the electroforming mold base in which an electroformed product is to be formed, the surface being in contact with the substrate;
an insulating resist layer covering the sacrificial layer except for at least a portion of a portion corresponding to a bottom surface of the cavity;
the electroforming mold base is formed in two or more layers in a thickness direction of the substrate, and has a step between each layer;
An electroforming mold, wherein an intermediate conductive layer is formed on the resist layer covering the sacrificial layer in the step portion. A conductive substrate;
an electroforming mold base disposed on the substrate;
a conductive sacrificial layer covering at least the surface of the substrate that faces a cavity formed by the substrate and the electroforming mold base, the surface being in contact with the substrate, the sacrificial layer being capable of separating the electroformed product from the electroforming mold by being dissolved in place of the electroforming mold base;
an insulating resist layer covering the sacrificial layer except for at least a portion of the portion corresponding to the bottom surface of the cavity portion. the sacrificial layer is formed so as to cover a part of a portion corresponding to a side surface of the cavity portion adjacent to a portion corresponding to a bottom surface of the cavity portion,
The electroforming mold according to claim 2 , wherein the resist layer covers the sacrificial layer except for a part of a portion corresponding to a side surface of the cavity portion adjacent to a portion corresponding to a bottom surface of the cavity portion. the electroforming mold base is formed in two or more layers in a thickness direction of the substrate, and has a step between each layer;
4. The electroforming mold according to claim 2 , wherein an intermediate conductive layer is formed on the resist layer covering the sacrificial layer in the step portion. 3. The electroforming mold according to claim 1 or 2 is used to grow plating in the cavity by electroplating;
A method for manufacturing an electroformed product using an electroforming mold, comprising: after the plating has grown to fill the hollow portion, dissolving at least the sacrificial layer out of the sacrificial layer and the resist layer without dissolving the electroforming mold base; and separating the electroformed product formed by plating that has filled the hollow portion from the electroforming mold. A method for manufacturing an electroformed product using an electroforming mold comprising: a conductive substrate; an electroforming mold base disposed on the substrate; a conductive sacrificial layer covering at least a surface of the substrate and a surface of the electroforming mold base that faces a cavity formed by the substrate and the electroforming mold base and in which an electroformed product is to be formed, the surface being in contact with the substrate; and an insulating resist layer covering the sacrificial layer except for at least a portion of a portion that corresponds to a bottom surface of the cavity,
growing a plating in the cavity by electroplating;
A method for manufacturing an electroformed product using an electroforming mold, comprising: after the plating has grown to fill the hollow portion, dissolving at least the sacrificial layer out of the sacrificial layer and the resist layer without dissolving the electroforming mold base; and separating the electroformed product formed by plating that has filled the hollow portion from the electroforming mold. 7. The method for producing an electroformed product using an electroforming mold according to claim 5 , further comprising removing the resist layer from the electroformed product after the electroformed product is separated from the electroforming mold.