JP7527184B2 - Manufacturing method of electroformed products and electroformed products - Google Patents

Description

The present invention relates to a method for manufacturing electroformed products and electroformed products.

For example, minute structures such as watch parts are manufactured by electroforming. Electroformed products formed from multi-layered (multi-stage) electroformed parts, whose contour shape varies depending on the position in the thickness direction, have also been proposed (see, for example, Patent Documents 1 and 2).

According to the technology described in Patent Document 1, a barrier layer is provided on the surface (surface in contact with the second layer (second stage) electroformed portion) of the first layer (first stage) electroformed portion (portion formed in the electroforming (plating) process), a second layer of resist is formed on the entire surface of the barrier layer and the first layer of resist, and after the second layer of resist is exposed and developed, the barrier layer on the surface of the first layer of electroformed portion is removed to form the second layer of electroformed portion in contact with the surface of the first layer of electroformed portion.

According to the technology described in Patent Document 2, a second layer of resist is formed on the entire surface of the first layer of electroformed part (the part formed in the electroforming (plating) process), and after the second layer of resist is exposed to light and developed, a second layer of electroformed part is formed in contact with the surface of the first layer of electroformed part.

Patent No. 6284144 European Patent Application Publication No. 2405301 (EP-A1-002405301)

In the technology described in Patent Document 1, when removing the barrier layer on the surface of the first electroformed portion, not only the barrier layer formed on the surface of the first electroformed portion that contacts the second electroformed portion is removed, but also the barrier layer in the area that contacts the resist of the second layer.

When this happens, a gap is formed between the first electroformed portion and the second resist layer, which corresponds to the barrier layer that was removed. As a result, the second electroformed portion is also formed in this gap, and the second electroformed portion, which should be outlined by the second resist layer, is formed in the gap outside the second resist layer, resulting in a problem of reduced dimensional accuracy of the shape of the electroformed portion.

In addition, in the technology described in Patent Document 2, an oxide film is formed on the surface of the electroformed portion of the first layer due to a reaction between the electroformed portion and oxygen in the air. The oxide film reduces the degree of bonding between the electroformed portion of the second layer and the electroformed portion of the first layer. Therefore, after the exposure and development of the second layer resist, the oxide film formed on the surface of the electroformed portion of the first layer must be removed using a strong acid or the like.

However, when this oxide film is removed, not only the oxide film formed on the surface of the first electroformed portion that comes into contact with the second electroformed portion is removed, but also the oxide film in the area that comes into contact with the resist of the second layer.

If this is done, as in the case of Patent Document 1, a gap corresponding to the removed oxide film is formed between the first electroformed portion and the second resist layer. As a result, the second electroformed portion is also formed in this gap, and the second electroformed portion, which should be outlined by the second resist layer, is formed in the gap outside the second resist layer, resulting in a problem of reduced dimensional accuracy of the shape of the electroformed portion.

The present invention has been made in consideration of the above circumstances, and aims to provide a manufacturing method for an electroformed product and an electroformed product that can prevent corrosion of the electroformed parts at the boundary between layers, improve the accuracy of the shape, and obtain sufficient adhesion between layers.

The first aspect of the present invention is a manufacturing method for an electroformed product in which electroformed parts formed by metal plating are stacked in the thickness direction to integrally form multiple layers of the electroformed parts. This manufacturing method for an electroformed product involves forming a metal film that is resistant to the formation of an oxide film and has good corrosion resistance on the surface of the previously formed electroformed part on which the next electroformed part will be stacked, forming a resist for the next electroformed part on the metal film, removing the part of the resist that corresponds to the next electroformed part by exposure and development, and forming the next electroformed part in the part from which the resist was removed.

The second aspect of the present invention is an electroformed product in which electroformed parts formed by metal plating are stacked in the thickness direction, and at the boundaries where steps occur between the stacked electroformed parts, there is no oxide film and a metal film with good corrosion resistance is formed.

The manufacturing method of electroformed products and electroformed products of the present invention can prevent corrosion of the electroformed parts at the layer boundaries, improve the accuracy of the shape, and obtain sufficient adhesion between the layers.

1A to 1C are schematic cross-sectional views (part 1) showing the flow of a method for manufacturing a two-layer electroformed product according to one embodiment of the present invention. 5 is a schematic cross-sectional view (part 2) showing the flow of a manufacturing method for a two-layer electroformed product of an embodiment. FIG. 5A to 5C are schematic cross-sectional views (part 3) showing the flow of a method for manufacturing a two-layer electroformed product according to an embodiment of the present invention. 4 is a schematic cross-sectional view (part 4) showing the flow of a manufacturing method for a two-layer electroformed product of an embodiment. 5 is a schematic cross-sectional view (part 5) showing the flow of a manufacturing method for a two-layer electroformed product of an embodiment. 6 is a schematic cross-sectional view (part 6) showing the flow of a manufacturing method for a two-layer electroformed product of an embodiment. 7 is a schematic cross-sectional view (part 7) showing the flow of a manufacturing method for a two-layer electroformed product of an embodiment. 8 is a schematic cross-sectional view (part 8) showing the flow of a manufacturing method for a two-layer electroformed product of an embodiment. 9 is a schematic cross-sectional view showing the flow of a manufacturing method for a two-layer electroformed product of an embodiment; FIG. 10 is a schematic cross-sectional view showing the flow of a manufacturing method for a two-layer electroformed product according to an embodiment of the present invention; FIG. FIG. 11 is a schematic cross-sectional view (part 11) showing the flow of a method for manufacturing a two-layer electroformed product according to an embodiment of the present invention. FIG. 12 is a schematic cross-sectional view showing the flow of a manufacturing method for a two-layer electroformed product according to an embodiment of the present invention; This is a schematic cross-sectional view (part 1) of an electroformed product at a step in a manufacturing method of variant 1, in which an electroformed product in which the second layer electroformed portion is larger in size than the first layer electroformed portion, corresponding to the step shown in Figure 1E. FIG. 2 is a schematic cross-sectional view (part 2) of an electroformed product at a step in the manufacturing method of modified example 1 corresponding to the step shown in FIG. 1H. 1C is a schematic cross-sectional view (part 3) of an electroformed product at a step in the manufacturing method of modified example 1 corresponding to the step shown in FIG. 1L. This is a schematic cross-sectional view of an electroformed product at the step of forming a first layer of resist on an overhanging layer in a manufacturing method of variant 2 for producing an electroformed product having a metal coating formed on the side of the first layer electroformed portion, corresponding to the step shown in Figure 1A. 13 is a schematic cross-sectional view of an electroformed product in a process of removing the first layer of resist after forming the first layer of electroformed portion in the manufacturing method of modified example 2. FIG. 13 is a schematic cross-sectional view of an electroformed product in a step of removing a portion of the overhanging layer in the manufacturing method of modified example 2. FIG. 13 is a schematic cross-sectional view of an electroformed product at a step in which a metal coating is formed on the surface, side surface, and upper surface of the substrate of the first layer electroformed portion in a manufacturing method of modified example 2. FIG. 13 is a schematic cross-sectional view of an electroformed product in a step of forming a second layer of resist in the manufacturing method of modified example 2. FIG. 13 is a schematic cross-sectional view of an electroformed product at a step in which a second layer electroformed portion is formed and the resist is removed in the manufacturing method of modified example 2. FIG. This is a schematic cross-sectional view of an electroformed product at a process in which the first layer electroformed portion and the second layer electroformed portion are integrated to form an electroformed product in which a metal coating is formed on the side surface of the first layer electroformed portion in the manufacturing method of variant example 2. 1 is a schematic cross-sectional view of an electroformed product in a process of removing the metal coating by etching, except for the portion directly below the first electroformed layer of the metal coating. FIG. 13 is a schematic cross-sectional view (part 1) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 3. 13 is a schematic cross-sectional view (part 2) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 3. 13 is a schematic cross-sectional view (part 3) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 3. 5 is a schematic cross-sectional view (part 4) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 3. 5 is a schematic cross-sectional view (part 5) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 3. 6 is a schematic cross-sectional view (part 6) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 3. 7 is a schematic cross-sectional view (part 7) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 3. 8 is a schematic cross-sectional view (part 8) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 3. 13 is a schematic cross-sectional view (part 1) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 4. 13 is a schematic cross-sectional view (part 2) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 4. 13 is a schematic cross-sectional view (part 3) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 4. 4 is a schematic cross-sectional view (part 4) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 4. 5 is a schematic cross-sectional view (part 5) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 4. 6 is a schematic cross-sectional view (part 6) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 4. 7 is a schematic cross-sectional view (part 7) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 4. FIG. 8 is a schematic cross-sectional view (part 8) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 4. 13 is a schematic cross-sectional view (part 1) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 5. 13 is a schematic cross-sectional view (part 2) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 5. 13 is a schematic cross-sectional view (part 3) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 5. 5 is a schematic cross-sectional view (part 4) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 5. 5 is a schematic cross-sectional view (part 5) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 5. 6 is a schematic cross-sectional view (part 6) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 5. FIG. 7 is a schematic cross-sectional view (part 7) showing the flow of a manufacturing method for a two-layer electroformed product of modified example 5.

Below, the manufacturing method of electroformed products and embodiments of electroformed products according to the present invention will be described with reference to the drawings.

Figures 1A to 1L are schematic cross-sectional views showing the flow of a manufacturing method for an electroformed product 100 according to one embodiment of the present invention. The manufacturing method for the electroformed product 100 shown in the figures is a manufacturing method for an electroformed product 100 in which two layers of electroformed portions 40, 80 formed by metal plating are stacked in the thickness direction to integrally form the electroformed portions 40, 80.

In this manufacturing method, first, a first layer of resist 20 is applied onto a conductive substrate 10 as shown in FIG. 1A.

The conductive substrate 10 may be formed of a conductive metal, or may be formed so as to exhibit conductivity by forming a conductive film on a substrate body such as a semiconductor such as silicon or a substrate body such as a non-conductive resin. The conductive substrate 10 may also be formed by laminating multiple types of metal.

The resist 20 is formed, for example, of a chemically amplified epoxy-based negative photoresist, but is not limited to negative type and may be, for example, a polymethyl methacrylate-based positive photoresist, etc.

In the manufacturing method of this embodiment, next, as shown in FIG. 1B, the resist 20 is irradiated (exposed) to UV light (ultraviolet light) L through a photomask 30 in which openings 31 and shielding portions 32 are formed. As a result, in the resist 20, there are formed areas (exposed areas) 21 in which the UV light L is irradiated through the openings 31, and areas (unexposed areas) 22 in which the UV light L is not irradiated due to the shielding portions 32.

Next, as shown in FIG. 1C, development is performed to remove the unexposed regions 22 of the resist 20, and a cavity 23 is formed corresponding to the portion where the unexposed regions 22 were previously located.

Next, as shown in FIG. 1D, the substrate 10 is used as the cathode to perform electroplating with nickel (Ni), forming a first layer electroplated portion 40 (a previously formed electroplated portion) made of nickel that fills the cavity 23, using the exposed area 21 and the substrate 10 as a mold.

The electroforming material is not limited to nickel, and any material that can be electroformed, such as copper (Cu), tin (Sn), and cobalt (Co), can be used. Here, if necessary, the surface 41 of the first layer of electroformed portion 40 and the surface of the first layer of resist 20 (exposure area 21) are ground and polished to be flat.

Next, the oxide film formed on the surface 41 of the first electroformed portion 40 (the surface on the side on which the next electroformed portion (the second electroformed portion 80) will be laminated (the upper surface in FIG. 1E)) is removed, and a metal film 50 is formed, which is a layer of a precious metal (e.g., a metal selected from the group consisting of gold (Au), silver (Ag), and platinum group elements) or an alloy of a precious metal (e.g., in the case of gold, an alloy that is difficult to form an oxide film, such as a gold-silver alloy, which is an alloy of gold and silver, or a gold-platinum alloy, which is an alloy of gold and platinum).

The metal coating 50 may have a titanium (Ti) or chromium (Cr) layer on the lower layer side, but must have a precious metal or a precious metal alloy formed on the upper layer side (exposed side).

Note that a metal coating 50 may also be formed on the surface of the exposed area 21 of the resist 20 other than the surface 41 of the electroformed portion 40. However, since the metal coating 50 on the surface of the exposed area 21 is eventually removed, it is not necessary for the electroformed product 100.

The metal coating 50 on only the surface 41 of the electroformed portion 40 may be formed by wet plating, or it may be formed by adhering a stencil mask with openings corresponding to the surface 41 of the electroformed portion 40 to the surface and then performing dry plating such as sputtering, vapor deposition, or ion plating. The metal coating 50 may also be formed by any of the methods described above on the entire surface of the electroformed portion 40, including the surface 41, after removing the exposed area 21 of the resist 20 in the first layer.

After forming a metal film 50 on the surface 41 of the electroformed portion 40, a second layer of resist 60 (resist for the next electroformed portion) is formed on the first layer of electroformed portion 40 and the exposed area 21 of the resist 20, as shown in FIG. 1F.

Next, as shown in FIG. 1G, the resist 60 is irradiated (exposed) with UV light L through a photomask 70 in which openings 71 and shielding portions 72 are formed. As a result, the second layer of resist 60 is formed with an area (exposed area) 61 where the UV light L is irradiated through the openings 71, and an area (unexposed area) 62 where the UV light L is not irradiated due to the shielding portions 72. The unexposed area 62 is formed so that at least a portion of it overlaps with the electroformed portion 40 of the first layer.

Next, as shown in FIG. 1H, development is performed to remove the unexposed regions 62 of the resist 60, and a cavity 63 (a portion corresponding to the next electroforming portion) corresponding to the unexposed regions 62 is formed. In addition, a portion of the exposed regions 61 of the resist 60 that have not been removed remains on the metal coating 50.

Here, the surface 41 of the first layer of electroformed portion 40 is covered with a metal coating 50, and in the area facing the cavity 63, the electroformed portion 40 is not exposed to the cavity 63, but rather the metal coating 50 covering the electroformed portion 40 is exposed.

In a case where the surface of the electroformed portion 40 is not covered with the metal film 50, which is different from the present embodiment, the surface of the electroformed portion 40 is exposed to air before the second layer of resist 60 is formed, and therefore the surface of the electroformed portion 40 oxidizes to form an oxide film. This oxide film is also formed by development that removes the unexposed areas 62 and exposure to the cavities 63.

The oxide film must be removed because it reduces the adhesion between the first-layer electroformed portion 40 and the second-layer electroformed portion 80 formed thereon. To remove the oxide film, a strong acid such as hydrochloric acid is used, and when the oxide film in the area facing the cavity 63 is removed with the strong acid, the strong acid penetrates into the boundary 65 between the surface 41 of the electroformed portion 40 and the remaining resist 60 (exposed area 61) of the second layer, and also removes the oxide film that was formed at this boundary 65.

When the oxide film at the boundary 65 is removed, a gap appears at the boundary 65, causing an error in the contour shape of the second layer electroformed portion 80, which will be described later. In addition, because the boundary 65 is narrow, corrosive oxide film removal solution and plating solution are likely to remain, which may corrode the surface of the electroformed portion 40.

In contrast, in the manufacturing method of this embodiment, the surface 41 of the first-layer electroformed portion 40 is covered with a metal film 50 as shown in FIG. 1H. The metal film 50 is composed of elements that are difficult to oxidize, and is almost never oxidized, so it has a better affinity with the second-layer electroformed portion 80 than an oxide film, and has high adhesion. Therefore, in the manufacturing method of this embodiment, since the metal film 50 is already present at the stage where the cavity 63 shown in FIG. 1H is formed, there is no need to perform a process of removing the oxide film using a strong acid.

If there is any residue of resist 60 on the surface of metal film 50 after development, the residue can be removed by plasma ashing or the like, and this plasma ashing will not cause gaps at boundary 65.

Next, as shown in FIG. 1I, electroplating with nickel is performed using the substrate 10 as the cathode, and the exposed area 61 and the electroplated portion 40 of the first layer are used as a mold to form the electroplated portion 80 of nickel that fills the cavity 63.

The electroforming material is not limited to nickel, and any material that can be electroformed, such as copper, tin, and cobalt, can be used. Here, if necessary, the surface of the second layer electroformed portion 80 and the surface of the second layer resist 60 (exposed area 61) are ground and polished to be flat.

Next, as shown in FIG. 1J, the first layer of resist 20 (exposed area 21) and the second layer of resist 60 (exposed area 61) are removed to form an electroformed product 100 in which the first layer of electroformed portion 40 and the second layer of electroformed portion 80, which has a different shape from the first layer, are integrated.

Next, as shown in FIG. 1K, if necessary, the metal film 50 formed at the boundary 65 of the electroformed product 100 is removed by etching (if necessary, the metal film 50 may be distinguished from the removed metal film 51 and the metal film 52 that remains without being removed). If the metal film 50 is gold, for example, an iodine-based etching solution may be used as the etching solution.

Finally, the electroformed product 100 is removed from the substrate 10 to obtain an electroformed product 100 in which the shapes of the two layers are integrated, as shown in FIG. 1L.

As described above, according to the manufacturing method of the electroformed product 100 of this embodiment, since there is no oxide film on the surface of the first electroformed portion 40, no gap is formed at the boundary 65 between the surface of the first electroformed portion 40 and the second resist layer 60.

This makes it possible to prevent errors in the contour shape, shape defects, and corrosion in the second-layer electroformed portion 80 caused by gaps at the boundary 65, thereby improving the dimensional accuracy of the manufactured electroformed product 100.

In addition, there is no need to remove the oxide film using, for example, a corrosive liquid (such as a strong acid) before electroplating the second layer.

The electroformed product 100 produced by the manufacturing method of this embodiment has a metal coating 50 formed at the boundary where a step occurs between the first layer electroformed portion 40 and the second layer electroformed portion 80. However, since the metal coating 50 has good adhesion between the electroformed portions 40 and 80, the strength of the integration between the electroformed portions 40 and 80 can be ensured.

In addition, the electroformed product 100 of this embodiment does not have an oxide film at the boundary between the first electroformed portion 40 and the second electroformed portion 80, so discoloration and loss of strength due to corrosion caused by residual corrosive oxide film removal solution or plating solution can be prevented.

<Modification 1>
In the manufacturing method of the electroformed product 100 and the electroformed product 100 of the above-mentioned embodiment, the second layer electroformed portion 80 formed later is smaller in size than the first layer electroformed portion 40 formed earlier, and as shown in Figure 1E, the second layer electroformed portion 80 is formed with a size corresponding to a portion of the area of the metal coating 50 that is formed only on the surface of the first layer electroformed portion 40 and is not formed on the surface of the exposed area 21 of the first layer resist 20.

However, the manufacturing method for electroformed products and electroformed products of the present invention are not limited to those in which the electroformed portion of the second layer is smaller in size than the electroformed portion of the first layer, and the electroformed portion of the second layer may be larger in size than the electroformed portion of the first layer, or the electroformed portion of the second layer may be the same size as the electroformed portion of the first layer.

For example, we will specifically explain variant 1 of the method for manufacturing an electroformed product 100 in which the second layer electroformed portion 80 is larger than the first layer electroformed portion 40.

Figure 1M is a schematic cross-sectional view (part 1) of an electroformed product in a step in the manufacturing method of variant 1, which produces an electroformed product in which the second-layer electroformed portion 80 is larger than the first-layer electroformed portion 40, corresponding to the step shown in Figure 1E.

In the process shown in FIG. 1E, the metal film 50 is formed only on the surface 41 of the electroformed portion 40. On the other hand, in the process shown in FIG. 1M, the metal film 50 is formed not only on the surface 41 of the electroformed portion 40 of the first layer, but also on the surface of the exposed region 21 of the resist 20 adjacent to the electroformed portion 40.

Even if the second layer electroformed portion 80 is larger than the first layer electroformed portion 40, the metal film 50 is formed only on the surface 41 of the electroformed portion 40, and the metal film 50 does not necessarily have to be formed on the surface of the exposed region 21 of the adjacent resist 20.

However, if a metal film 50 is also formed on the surface of the exposed region 21 of the adjacent resist 20, the growth of plating can be promoted in the region of the second-layer electroformed portion 80 that protrudes in the width direction from the first-layer electroformed portion 40, so it is preferable to also form a metal film 50 on the surface of the exposed region 21 of the adjacent resist 20.

The metal coating 50 may also be formed to match the shape of the second-layer electroformed portion 80. In this case, the metal coating 50 can be formed to match the shape of the second-layer electroformed portion 80 by etching using a stencil mask or photolithography.

After forming a metal film 50 on the surface 41 of the first layer of electroformed portion 40 and the surface of the exposed area 21 of the resist 20 (Figure 1M), a second layer of resist 60 is formed on the metal film 50 as in Figure 1F, and the resist 60 is irradiated (exposed) to UV light L through a photomask 70 as in Figure 1G.

The light-shielding portion 72 of the photomask 70 is formed to a size corresponding to the second layer electroformed portion 80, i.e., a size larger than the first layer electroformed portion 40.

Figure 1N is a schematic cross-sectional view (part 2) of an electroformed product at a step in the manufacturing method of variant 1, which corresponds to the step shown in Figure 1H of the above embodiment.

The unexposed regions 62 of the second layer of resist 60, which are shielded by the photomask 70, are subsequently removed by development, as shown in FIG. 1N (the drawing corresponding to FIG. 1H). At this time, the metal film 50 remains exposed over the entire bottom of the cavity 63 formed by removing the unexposed regions 62.

Next, similar to the process in FIG. 1I, electroplating is performed using the substrate 10 as the cathode to form a second electroformed portion 80 made of nickel that fills the cavity 63. This forms a second electroformed portion 80 that is larger in size than the first electroformed portion 40.

Then, similar to the process of FIG. 1J, the remaining portions of the second layer resist 60 and the first layer resist 20, excluding the second layer electroformed portion 80 and the first layer electroformed portion 40, are removed.

At this time, unlike the above embodiment, the metal film 50 is formed on the surface of the first layer of resist 20, so the second layer of resist 60 covering the first layer is removed. However, since the first layer of resist 20 is covered by the metal film 50, it may not be possible to remove the first layer of resist 20 at the same time in the process of removing the second layer of resist 60.

Therefore, if the first layer of resist 20 cannot be removed at the same time in the process of removing the second layer of resist 60, after removing the second layer of resist 60, the metal coating 50 covering the surface of the first layer of resist 20 in the area protruding from the electroformed portion 80 of the second layer is removed by etching, and after this metal coating 50 is removed, the first layer of resist 20 is removed.

Figure 1O is a schematic cross-sectional view (part 3) of an electroformed product at a step in the manufacturing method of variant 1, which corresponds to the step shown in Figure 1L of the above embodiment.

Finally, by removing the electroformed product 100 from the substrate 10, an electroformed product 100 can be obtained in which the first electroformed portion 40 and the second electroformed portion 80, which has a different shape from the first layer and is larger in size, are integrated together, as shown in FIG. 1O.

In addition, the metal coating 50 on the bottom surface of the second-layer electroformed portion 80, which protrudes from the area between the first-layer electroformed portion 40 and the second-layer electroformed portion 80, may be removed by etching if necessary.

In this way, even with the manufacturing method of the electroformed product 100 in which the second-layer electroformed portion 80 is formed to be larger in size than the first-layer electroformed portion 40, no gaps are formed at the boundary 65 (see Figure 1N) between the surface of the first-layer electroformed portion 40 and the second-layer resist 60, improving the dimensional accuracy of the manufactured electroformed product 100.

This allows the same effects and advantages to be achieved as in the manufacturing method of the electroformed product 100 in which the second layer electroformed portion 80 is formed to a smaller size than the first layer electroformed portion 40.

<Modification 2>
In the manufacturing method of the electroformed product 100 and the electroformed product 100 of the above-mentioned embodiment, a metal coating 50 is not formed on the side of the electroformed part 100 (the surface along the stacking direction in which the first layer electroformed portion 40 and the second layer electroformed portion 80 are stacked).

However, since the surface on which the metal coating 50 is formed can have improved wear resistance, corrosion resistance, and decorativeness, when the manufactured electroformed product 100 is applied to a part (e.g., a gear, a watch dial, a watch index) where improved wear resistance, corrosion resistance, and decorativeness of the side surface are required, it is preferable to form the metal coating 50 on the side surface of the electroformed product 100.

Therefore, for example, a manufacturing method of variant 2 for manufacturing an electroformed product 100 in which a metal coating 50 is formed on the side surface of the first layer of electroformed portion 40 will be described, highlighting the differences from the above-mentioned embodiment.

Figure 1P is a schematic cross-sectional view of an electroformed product in the step of forming a first layer of resist 20 on a substrate 10 in a manufacturing method of variant 2 for manufacturing an electroformed product 100 having a metal coating 50 formed on the side surface 40a of the first layer of electroformed portion 40, which corresponds to the step shown in Figure 1A.

In the process shown in FIG. 1A, the first layer of resist 20 is directly laminated on the substrate 10. On the other hand, in the process shown in FIG. 1P, before forming the first layer of resist 20 on the substrate 10, an overhanging layer 11 is formed on the substrate 10, and the first layer of resist 20 is then formed on this overhanging layer 11.

Here, the overhanging layer 11 is a layer that forms a gap between the substrate 10 and the first electroformed portion 40, so that the bottom edge of the first electroformed portion 40, which will be described later, has a shape that overhangs the substrate 10 in the shape of an overhang. The overhanging layer 11 is made of a conductive material different from the metal that forms the metal film 50.

Figure 1Q is a schematic cross-sectional view of an electroformed product 100 in a process in which the first layer of resist 20 is removed after the first layer of electroformed portion 40 is formed in the manufacturing method of variant example 2. As shown in Figure 1P, the first layer of resist 20 is formed on the overhanging formation layer 11, and then the first layer of electroformed portion 40 is formed in the same manner as in the processes of Figures 1B to 1D. Thereafter, the first layer of resist 20 is removed as shown in Figure 1Q, and further, a portion of the overhanging formation layer 11 on the substrate 10 is removed by etching.

Figure 1R is a schematic cross-sectional view of the electroformed product 100 in the process of removing a portion of the overhanging layer 11 in the manufacturing method of variant 2. When the overhanging layer 11 is removed by etching, typically only the overhanging layer 11 that faces the resist 20 is removed by etching, but in variant 2, the etching time is extended, and as shown in Figure 1R, a portion of the overhanging layer 11 between the first electroformed portion 40 and the substrate 10 is also removed.

Specifically, a portion of the overhanging layer 11 between the first electroformed portion 40 and the substrate 10 is removed so that the side surface 11a of the overhanging layer 11 between the first electroformed portion 40 and the substrate 10 is recessed inward from the side surface 40a of the electroformed portion 40.

As a result, a gap 12 is formed between the first electroformed portion 40 and the substrate 10, below the edge of the electroformed portion 40 adjacent to the side surface 40a of the first electroformed portion 40, where the overhanging layer 11 has been removed, and in this gap 12, the edge of the electroformed portion 40 adjacent to the side surface 40a of the electroformed portion 40 becomes overhanging with respect to the substrate 10.

Figure 1S is a schematic cross-sectional view of the electroformed product 100 in the process of forming a metal coating 50 on the surface 41 and side 40a of the first-layer electroformed portion 40 and on the upper surface of the substrate 10 in the manufacturing method of variant example 2. In the state shown in Figure 1R, the metal coating 50 is formed by sputtering or vapor deposition, as in Figure 1E. As a result, as shown in Figure 1S, the metal coating 50 is formed on the surface 41 and side 40a corresponding to the upper surface of the first-layer electroformed portion 40, and on the upper surface of the substrate 10.

In addition, a gap 12 is formed below the edge of the electroformed portion 40 adjacent to the side surface 40a of the electroformed portion 40 of the first layer, so the metal coating 50 formed on the side surface 40a of the electroformed portion 40 and the metal coating 50 formed on the upper surface of the substrate 10 are not connected, but a gap is formed.

Figure 1T is a schematic cross-sectional view of the electroformed product 100 in the process of forming the second layer of resist 60 in the manufacturing method of variant example 2. As shown in Figure 1T, the second layer of resist 60 is formed to completely cover the first layer of electroformed portion 40 and to a height range that allows the second layer of electroformed portion 80 to be formed on the first layer of electroformed portion 40.

Figure 1U is a schematic cross-sectional view of an electroformed product 100 in a process in which a second-layer electroformed portion 80 is formed and resist 60 is removed in the manufacturing method of modified example 2, and Figure 1V is a schematic cross-sectional view of an electroformed product 100 in a process in which a first-layer electroformed portion 40 and a second-layer electroformed portion 80 are integrated to form an electroformed product 100 in which a metal coating 50 is formed on the side surface 40a of the first-layer electroformed portion 40 in the manufacturing method of modified example 2.

As in the steps of Figures 1G to 1I, a second-layer electroformed portion 80 is formed on the first-layer electroformed portion 40 via a metal film 50, and as in Figure 1J, the resist 60 is removed as shown in Figure 1U, and finally, the overhanging layer 11 is removed by etching. This makes it possible to manufacture an electroformed product 100 in which a metal film 50 is formed on the side surface 40a of the first-layer electroformed portion 40 as shown in Figure 1V.

As shown in FIG. 1U, a gap is formed between the metal film 50 formed on the side surface 40a of the first-layer electroformed portion 40 and the metal film 50 formed on the substrate 10, so that the etching solution for removing the overhanging layer 11 can penetrate between the first-layer electroformed portion 40 and the substrate 10 through the gap.

As a result, the overhanging layer 11 formed between the first electroformed portion 40 and the substrate 10 can be easily removed with an etching solution in the structure shown in FIG. 1U, compared to a structure without a gap (where the first electroformed portion 40 is formed directly on the substrate 10 without the overhanging layer 11 in between).

In the example shown in FIG. 1Q, the electroformed portion 40 is formed in contact with the overhanging layer 11, but it is also possible to form a metal coating 50 on the upper surface of the overhanging layer 11 and then form the electroformed portion 40 on the metal coating 50.

Figure 1W is a schematic cross-sectional view of an electroformed product 100 in a process of removing the metal film 50 by etching, except for the portion directly below the first electroformed portion 40. Prior to removing a portion of the overhanging layer 11 between the first electroformed portion 40 and the substrate 10 to form a gap 12 as shown in Figure 1R, the metal film 50 formed on the overhanging layer 11 is removed by etching, except for the portion directly below the first electroformed portion 40, as shown in Figure 1W.

At this time, it is not necessary to remove the metal film 50 directly below the electroformed portion 40 to a position recessed inward from the side surface 40a of the electroformed portion 40, as in the case of the overhanging layer 11 described above. After that, as in FIG. 1R, it is sufficient to remove the overhanging layer 11 between the first electroformed portion 40 (the metal film 50 remaining directly below it) and the substrate 10 to a position recessed inward from the side surface 40a of the electroformed portion 40.

In this way, even with the manufacturing method of the electroformed product 100 of variant 2, in which the metal film 50 is left on the side surface 40a of the first layer electroformed portion 40, no gaps are formed at the boundary 65 (see Figure 1T) between the surface of the first layer electroformed portion 40 and the second layer resist 60, improving the dimensional accuracy of the manufactured electroformed product 100.

This allows the same effects and advantages to be achieved as in the manufacturing method of the electroformed product 100 in which the second-layer electroformed portion 80 is formed to a smaller size than the first-layer electroformed portion 40, and also improves the wear resistance, corrosion resistance, and decorativeness of the side surface 40a of the first-layer electroformed portion 40.

<Modification 3>
In the electroformed product 100 of the embodiment, the second layer electroformed portion 80 is integrated in a state in which it is placed on the surface 41 of the first layer electroformed portion 40. However, if the second layer electroformed portion 80 is integrated in a state in which a part (anchor portion) of the second layer electroformed portion 80 is inserted into the first layer electroformed portion 40, the shear strength at the boundary between the first layer electroformed portion 40 and the second layer electroformed portion 80 can be improved.

Figures 2A to 2H are schematic cross-sectional views showing the flow of a manufacturing method for a two-layer electroformed product 100, which is a modified example (modified example 3) of the embodiment shown in Figures 1A to 1L. In the manufacturing method of the illustrated modified example 3, first, as shown in Figure 2A, a first layer of resist 20 is applied onto a conductive substrate 10, and similarly to the above-mentioned embodiment, an exposed area 21 and an unexposed area 22 are formed in the resist 20 by irradiating UV light L using a photomask 30, and the unexposed area 22 is removed to form the electroformed portion 40.

At this time, the exposed area 21 between the two unexposed areas 22 (corresponding to the electroformed portion 40 in the figure) corresponds to the cavity in which the anchor portion 81 will be formed later in the second layer electroformed portion 80.

Then, after development, plating is performed to form the first layer of electroformed portions 40 in the areas corresponding to the two unexposed areas 22.

Next, as shown in FIG. 2B, when the exposed area 21 of the first layer of resist 20 is completely removed, a cavity 24 is formed between the two electroformed portions 40. Then, the entire surface including the surfaces 41 of the two electroformed portions 40 is dry-plated or wet-plated to form a gold film 50 on the surfaces 41 of the electroformed portions 40, as shown in FIG. 2C. The metal film 50 is formed after the oxide film on the surfaces of the electroformed portions 40 has been removed in advance.

After forming a metal film 50 on the surface 41 of the electroformed portion 40, a second layer of resist 60 is formed on the substrate 10 so as to cover the top of the first layer of electroformed portion 40, as shown in FIG. 2D.

Next, as shown in FIG. 2E, UV light L is irradiated onto the resist 60 through a photomask 90 in which openings 91 and shielding portions 92 are formed. As a result, the resist 60 is formed into an area (exposed area) 61 where the UV light L is irradiated through the openings 91, and an area (unexposed area) 62 where the UV light L is not irradiated due to the shielding portions 92. The unexposed area 62 is formed so that at least a portion of it straddles the two electroformed portions 40 of the first layer, i.e., so as to include a cavity 24.

Next, as shown in FIG. 2F, development is performed to remove the unexposed regions 62 of the resist 60, and a cavity 63 corresponding to the portion where the unexposed regions 62 were previously located is formed. This cavity 63 includes the cavity 24 between the two electroformed portions 40 of the first layer.

Here, the surface 41 of the first layer electroformed portion 40 is covered with the metal film 50, and in the area facing the cavity 63, the electroformed portion 40 is not exposed to the cavity 63, but the gold film 50 covering the electroformed portion 40 is exposed. Also, part of the exposed area 61 of the resist 60 that was not removed remains on the metal film 50.

Next, as shown in FIG. 2G, electroplating with nickel is performed using the substrate 10 as the cathode, and the exposed area 61, the electroformed portion 40 of the first layer, and the substrate 10 are used as a mold to form the electroformed portion 80 of the second layer made of nickel that fills the cavity 63. Here, a part of the electroformed portion 80 of the second layer forms an anchor portion 81 inserted into the cavity 24 between the two electroformed portions 40 of the first layer.

The electroforming material is not limited to nickel, and any material that can be electroformed, such as copper, tin, and cobalt, can be used.

Next, if necessary, the surface of the second layer electroformed portion 80 and the surface of the second layer resist 60 (exposed area 61) are ground and polished to be flat, and the second layer resist 60 (exposed area 61) is removed to form an electroformed product 100 in which the first layer electroformed portion 40 and the second layer electroformed portion 80, which has a different shape from the first layer, are integrated.

Then, if necessary, the metal film 50 formed at the boundary 65 (see FIG. 2F) of the electroformed product 100 is removed by etching, and finally, the electroformed product 100 is removed from the substrate 10, thereby obtaining an electroformed product 100 in which the shapes of the two layers are integrated, as shown in FIG. 2H.

In this way, the electroformed product 100 manufactured by the manufacturing method of variant example 3 not only achieves the same effect as the electroformed product 100 of the embodiment, but also improves the shear strength at the boundary where a step occurs between the electroformed portion 40 of the first layer and the electroformed portion 80 of the second layer, since a portion of the electroformed portion 80 of the second layer is inserted into the cavity 24 of the electroformed portion 40 of the first layer as an anchor portion 81 and is integrated.

<Modification 4>
In the manufacturing method of the electroformed product 100 of variant example 3, after the first layer of electroformed portion 40 is formed (see Figure 2A), the first layer of resist 20 (exposed area 21) is removed before the metal coating 50 is formed (see Figure 2C). However, the manufacturing method of the electroformed product of the present invention is not limited to this form.

Figures 3A to 3H are schematic cross-sectional views showing the flow of a manufacturing method for a two-layer electroformed product 100, which is variant example 4.

The manufacturing method of the electroformed product 100 of the modified example 4 is another modified example of the embodiment shown in Figures 1A to 1L, and is the same as the modified example 3 except for some steps. In the manufacturing method of the modified example 4, after forming the first layer of electroformed portion 40 (see Figure 3A), as shown in Figure 3B, a metal coating 50 is formed on the surface 41 of the first layer of electroformed portion 40, and then the first layer of resist 20 (exposed area 21) is removed as shown in Figure 3C.

Here, the metal film 50 is formed on the surface 41 of the first layer electroformed portion 40 by dry plating using a stencil mask 110 in which openings 111 corresponding to the surface 41 of the electroformed portion 40 are formed, as shown in FIG. 3B. The metal film 50 can also be formed by wet plating, but attention must be paid to the possibility that when removing the oxide film on the surface of the electroformed portion 40, the removal liquid may seep into the gaps with the resist 21 and remain, causing corrosion.

As a result, the metal film 50 is formed only on the surface 41 of the electroformed portion 40, and the metal film 50 is not formed on the surface of the resist 20 corresponding to the shielded portion other than the opening 111. As a result, the metal film 50 can be formed in a smaller amount than in the third modification, and the amount of expensive precious metal used to form the metal film 50 can be reduced.

After the metal film 50 is formed on the surface 41 of the electroformed portion 40 (FIG. 3B), the exposed areas 21 of the first layer of resist 20 are all removed as shown in FIG. 3C, and then a second layer of resist 60 is formed on the substrate 10 so as to cover the top of the first layer of electroformed portion 40 (FIG. 3D).

Next, as shown in FIG. 3E, UV light L is irradiated onto the resist 60 through a photomask 90 in which openings 91 and shielding portions 92 are formed. As a result, the resist 60 is formed with an area (exposed area) 61 where the UV light L is irradiated through the openings 91, and an area (unexposed area) 62 where the UV light L is not irradiated due to the shielding portions 92. The unexposed area 62 is formed so that at least a portion of it straddles the two electroformed portions 40 of the first layer, i.e., so as to include the cavity 24 of the electroformed portion 40 of the first layer.

Next, as shown in FIG. 3F, development is performed to remove the unexposed regions 62 of the resist 60, and a cavity 63 is formed corresponding to the portion where the unexposed regions 62 were previously located. This cavity 63 includes the cavity 24 between the two electroformed portions 40 of the first layer.

Here, the surface 41 of the first layer electroformed portion 40 is covered with a metal coating 50, and the area facing the cavity 63 other than the surface 41 is exposed to the cavity 63.

Therefore, before the next electroplating, it is necessary to remove the oxide film on the side of the electroformed portion 40 facing the cavity 63. At this time, since the metal film 50 is present at the boundary 65 between the resist 60 (exposed region 61) and the electroformed portion 40, no voids are generated at the boundary 65. Note that the part of the exposed region 61 of the resist 60 that has not been removed remains on the metal film 50.

Next, as shown in FIG. 3G, electroplating with nickel is performed using the substrate 10 as the cathode, and the exposed area 61, the electroformed portion 40 of the first layer, and the substrate 10 are used as a mold to form the electroformed portion 80 of the second layer made of nickel that fills the cavity 63. Here, a part of the electroformed portion 80 of the second layer forms an anchor portion 81 inserted into the cavity 24 between the two electroformed portions 40 of the first layer.

The electroforming material is not limited to nickel, and any material that can be electroformed, such as copper, tin, and cobalt, can be used.

Next, if necessary, the surface of the second layer electroformed portion 80 and the surface of the second layer resist 60 (exposed area 61) are ground and polished to be flat, and the second layer resist 60 (exposed area 61) is removed to form an electroformed product 100 in which the first layer electroformed portion 40 and the second layer electroformed portion 80, which has a different shape from the first layer, are integrated.

Then, the metal film 50 formed at the boundary 65 (see FIG. 3F) of the electroformed product 100 is removed by etching, and finally, the electroformed product 100 is removed from the substrate 10, thereby obtaining an electroformed product 100 in which the shapes of the two layers are integrated, as shown in FIG. 3H.

In this way, the electroformed product 100 manufactured by the manufacturing method of variant example 4 not only achieves the same effect as the electroformed product 100 of the embodiment, but also improves the shear strength at the boundary between the electroformed portion 40 of the first layer and the electroformed portion 80 of the second layer, since a portion of the electroformed portion 80 of the second layer is inserted into the cavity 24 of the electroformed portion 40 of the first layer as an anchor portion 81 and is integrated.

In addition, the amount of metal coating 50 used can be reduced compared to the manufacturing method of variant 3, reducing manufacturing costs.

In addition, the boundary (periphery) between the anchor portion 81 in the second-layer electroformed portion 80 and the first-layer electroformed portion 40 can be structured so that the same type of metal (e.g., nickel) is in direct contact with each other without the metal coating 50 interposed therebetween, resulting in improved affinity and higher adhesion compared to a structure in which the metal coating 50 is interposed, and further increasing the strength of the integration between the first-layer electroformed portion 40 and the second-layer electroformed portion 80.

<Modification 5>
In the electroformed product 100 of variants 3 and 4, the anchor portion 81 of the second layer electroformed portion 80 is inserted into the first layer electroformed portion 40, thereby improving the shear strength at the boundary between the first layer electroformed portion 40 and the second layer electroformed portion 80. However, by having the first layer electroformed portion 40 have a constricted portion and forming the tip portion of the anchor portion 81 larger than the constricted portion, the strength against tension in the stacking direction between the first layer electroformed portion 40 and the second layer electroformed portion 80 can be made stronger than that of the electroformed product 100 of variants 3 and 4.

The manufacturing method of the electroformed product 100 of variant 5 involves forming a narrowed portion 24b in the cavity 24 of the first layer electroformed portion 40 in the electroformed product 100 of variants 3 and 4, closer to the second layer electroformed portion 80, than the tip portion 24a, which is the farther portion, and forming the tip portion 81a of the anchor portion 81 of the second layer electroformed portion 80 to be thicker than the base portion 81b.

Figures 4A to 4G are schematic cross-sectional views showing the flow of a manufacturing method for a two-layer electroformed product 100, which is variant example 5.

The manufacturing method of the electroformed product 100 of the fifth modified example is to first form a cavity-forming member 120 made of, for example, copper on a conductive substrate 10, as shown in FIG. 4A, which corresponds to the tip 81a of the anchor portion 81 of the second-layer electroformed portion 80. The cavity-forming member 120 will later form the tip 24a of the cavity 24. At this time, the cavity-forming member 120 needs to be a different element from the electroformed portion 40, since it will need to be selectively removed later.

Then, resist 20 is applied so as to cover this cavity-forming member 120, and as shown in FIG. 4B, the resist 20 is irradiated with UV light L through a photomask 30 in which openings 31 and shielding portions 32 are formed so that the portion of the resist 20 corresponding to the center of the cavity-forming member 120 (the portion thinner than the cavity-forming member: the portion that will later form the constricted portion 24b) is the exposed region 21, and the portions corresponding to both sides of the cavity-forming member 120 and their outer portions are the unexposed regions 22.

Next, as shown in FIG. 4C, the unexposed regions 22 of the resist 20 are removed by development, forming a cavity 23 on both sides of the cavity-forming member 120 and portions corresponding to the outer portions thereof.

Next, as shown in FIG. 4D, the remaining exposed area 21 of the resist 20 and the substrate 10 are used as a mold to form a first layer electroformed portion 40 of nickel that fills the cavity 23, for example, by electrolytic nickel plating. Here, because the cavity-forming member 120 and the exposed area 21 of the resist 20 remain on the substrate 10, the first layer electroformed portion 40 has a shape that does not have a central portion.

Next, if necessary, grinding and polishing are performed so that the surface of the first layer of electroformed portion 40 and the surface of the first layer of resist 20 (exposed area 21) are flat.

Next, a metal film 50 is formed on the surface 41 of the first electroformed portion 40 by dry plating or wet plating using a stencil mask 110 in which openings 111 corresponding to the surface 41 of the first electroformed portion 40 are formed, and then the exposed areas 21 of the resist 20 are removed as shown in FIG. 4D.

Next, as shown in FIG. 4E, the cavity-forming member 120 is removed by etching. For example, if the cavity-forming member 120 is made of copper, the cavity-forming member 120 is selectively removed using an ammonium peroxodisulfate-based etching solution.

As a result, a cavity 24 is formed in the first layer electroformed portion 40 on the side closer to the second layer electroformed portion 80 to be laminated, with a narrowed portion 24b that is thinner than the tip portion 24a, which is the farther portion.

Next, a second layer of resist 60 is formed on the substrate 10 so as to cover the first layer of electroformed portion 40.

Next, as shown in FIG. 4F, UV light L is irradiated onto the resist 60 through a photomask 90 in which openings 91 and shielding portions 92 are formed. As a result, the resist 60 is formed with an exposed region 61 irradiated with the UV light L through the openings 91, and an unexposed region 62 not irradiated with the UV light L by the shielding portions 92. The unexposed region 62 is formed so that at least a portion of it straddles the two electroformed portions 40 of the first layer, i.e., so as to include the narrowed portion 24b of the cavity 24.

Next, as shown in FIG. 4G, development is performed to remove the unexposed areas 62 of the resist 60, and a cavity 24 is formed corresponding to the area where the unexposed areas 62 were previously located. For example, electroplating with nickel is performed to form a second-layer electroplated portion 80 made of nickel that fills the cavity 24, using the exposed areas 61, the first-layer electroplated portion 40, and the substrate 10 as a mold.

Here, a part of the electroformed portion 80 of the second layer forms an anchor portion 81 inserted into the cavity 24 between the two electroformed portions 40 of the first layer. This anchor portion 81 has a tip portion 81a formed corresponding to the tip portion 24a of the cavity 24 that is thicker than a base end portion 81b formed corresponding to the constricted portion 24b of the cavity 24. In other words, the tip portion 81a of the anchor portion 81 is formed thicker than the constricted portion 24b of the cavity 24.

Next, the second layer of resist 60 (exposed area 61) is removed to form an electroformed product 100 in which the first layer of electroformed portion 40 and the second layer of electroformed portion 80, which has a different shape from the first layer, are integrated.

Then, by removing the electroformed product 100 from the substrate 10, an electroformed product 100 with the two layers integrated into one shape can be obtained, as shown in Figure 4G.

In this way, the electroformed product 100 manufactured by the manufacturing method of variant example 5 not only achieves the same effect as the electroformed product 100 of the embodiment, but also improves the shear strength at the boundary between the first layer electroformed portion 40 and the second layer electroformed portion 80, since a portion of the second layer electroformed portion 80 is inserted into the first layer electroformed portion 40 as an anchor portion 81 and integrated therewith.

Furthermore, the electroformed product 100 manufactured by the manufacturing method of variant 5 has a first-layer electroformed portion 40 with a constricted portion 24b, and the tip portion 81a of the anchor portion 81 of the second-layer electroformed portion 80 is formed thicker than the constricted portion 24b, so that the first-layer electroformed portion 40 and the second-layer electroformed portion 80 are prevented from coming loose when pulled in the stacking direction, and the electroformed product 100 can have a stronger tensile strength than the electroformed products 100 of variants 3 and 4.

The tip 81a and base 81b of the anchor portion 81 shown in variant example 5 are connected by a portion extending in the stacking direction between the first electroformed portion 40 and the second electroformed portion 80, but instead of a portion extending in the stacking direction, they may be connected by a tapered portion that expands from the base 81b toward the tip 81a.

The electroformed product 100 in the above-mentioned embodiment and each modified example is, for example, a tip part that is pressed into the pallet of a mechanical watch and fixed thereto (the electroformed part 40 in the first layer is the beam part, and the electroformed part 80 in the second layer is the shaft part that is pressed into the pallet), but the manufacturing method of the electroformed product 100 and the electroformed product 100 in the embodiment and each modified example are not limited to the tip parts described above, and can be applied to various parts (gears, etc.) used in watches, and can also be applied to various items other than watches.

The electroformed product manufacturing method and electroformed product of the present invention are particularly suitable for use in integral parts in which the first and second layers have different contour shapes.

The present invention can be applied to any integral electroformed product having two or more layers with different contour shapes between the layers, and is not limited to electroformed products with only two layers.

40: First layer electroformed portion 41: Surface 50: Metal coating 60: Resist 62: Unexposed region 80: Second layer electroformed portion 100: Electroformed product L: UV light

Claims (6)

A method for manufacturing an electroformed product, comprising stacking electroformed parts formed by metal plating in a thickness direction to integrally form a plurality of layers of the electroformed parts, the method comprising the steps of:
forming a metal coating of a precious metal or a metal coating of a precious metal alloy, which is resistant to the formation of an oxide film and has good corrosion resistance, on the surface of the previously formed electroformed portion on which the next electroformed portion is to be laminated;
Next, a resist for the next electroforming portion is formed on the metal film;
Next, the portion of the resist corresponding to the next electroformed portion is removed by exposure and development;
forming the next electroformed portion on the portion from which the resist has been removed;
A method for manufacturing an electroformed product , comprising removing an oxide film from the surface of the electroformed part formed in advance, prior to forming the metal film . The method for manufacturing an electroformed product according to claim 1, wherein before the next electroformed part is formed, at least a portion of the resist that has not been removed to form the next electroformed part is left on the metal coating. forming a cavity in a layer corresponding to the previously formed electroformed portion;
3. The method for manufacturing an electroformed product according to claim 1, further comprising the step of forming an anchor portion inserted into the cavity in the subsequent electroformed part. forming a narrowed portion in a portion of the cavity closer to the next electroformed portion than a portion of the cavity farther from the next electroformed portion;
The method for manufacturing an electroformed product according to claim 3 , wherein a portion of the anchor portion that is inserted into a portion of the cavity farther from the next electroformed portion is formed to be thicker than the constricted portion. forming an overhanging layer on a substrate, the overhanging layer being made of a conductive material different from the metal film;
The electroformed portion to be formed in advance is formed on the overhanging layer;
The overhanging layer is removed to a position recessed inward from the side surface of the previously formed electroformed portion,
forming the metal coating on the substrate and the previously formed electroformed portion;
By removing the overhanging layer to the recessed position, a gap is formed between the metal film formed on the substrate and the metal film formed on the side surface of the previously formed electroformed portion,
A method for manufacturing an electroformed product described in any one of claims 1 to 4, wherein after the next electroformed portion is formed on the previously formed electroformed portion via the metal coating, the overhanging layer remaining between the previously formed electroformed portion and the substrate is removed by etching through the gap. forming the metal coating on the overhang-forming layer prior to forming the electroformed portion formed in advance on the overhang-forming layer;
The method for producing an electroformed product according to claim 5 , further comprising forming the previously formed electroformed portion on the metal coating.