Method for producing electric casting and parts of watch

Abstract

To provide a method for producing electric casting by which the degree of sharpness of the corners at the bottom of a recess where plating is grown is reduced and the processing of the corners is performed without manual operation.SOLUTION: In a method for producing an electric casting 100, a photoresist layer 20 corresponding to the shape of the electric casting 100 is formed on a conductive substrate 10, a substrate 10 on which the photoresist layer 20 is not formed is sputtered, a conductive material is scattered from the conductive layer 12 of the substrate 20, the scattered conductive material is adhered to a side surface 21a of the photoresist layer 20, a metal is deposited from the conductive layer 12a adhered to the conductive layer 12 and the side surface 21 in a cavity 23 which is a region on which the photoresist layer 20 is not formed by wet plating to form the electric casting 100, and the photoresist layer 20 is removed to produce the electric casting 100.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing electroformed products and watch parts. [Background technology]

[0002] For example, electroforming (a method for manufacturing, repairing, or replicating metal products using electroplating; hereafter referred to as electroforming) is known as a technique for manufacturing minute structures such as watch parts. The LIGA (Lithographie, Galvanoformung, Abformung) method is becoming more widely used in the electroforming manufacturing process. In the LIGA method, a photoresist layer is formed on a substrate, and a pattern of soluble and insoluble parts is formed in the photoresist layer to manufacture a mold for forming an electroformed product for plating. Molds (electroforming molds) manufactured using the LIGA method can be formed into molds with fine and highly accurate contours.

[0003] Here, when using an electroforming mold to manufacture an electroformed product having a shape with an inclined surface on the outer peripheral edge of the upper or lower surface, in addition to the bottom surface of the electroforming mold, the side surface adjacent to the bottom surface may also be made conductive.

[0004] For example, when forming soluble and insoluble parts of a photoresist, an electroforming mold is irradiated with light (ultraviolet rays, etc.) in a linear manner, and therefore the corners at the bottom of the concave space formed in the subsequent development process (corresponding to the part where the bottom surface and side surface of the electroformed object meet) become sharp.

[0005] Therefore, the corners of the electroformed product produced using the electroforming mold are also sharp, and when the electroformed product is combined with other fixtures, the other parts may be scraped by the sharp corners of the electroformed product, and the desired specifications may not be obtained. Therefore, in a process after the LIGA process, it was necessary to perform barrel polishing or other processing such as making the corners of the lower surface of the electroformed product into an inclined surface or forming roundness at the corners.

[0006] However, when barrel polishing is performed in a later process to reduce the sharpness of corners, for example, the shape of the electroformed product, such as a seconds stop lever part having a long and thin portion, may become tangled or deformed due to the agitation caused by the barrel polishing. Also, there is a risk that vibration-resistant pressure spring parts, which are formed thin to give them elasticity, may become deformed.

[0007] Therefore, a technique has been proposed in which, during the LIGA process, a conductive hardener is manually placed, using a microsyringe or pipette, into the bottom corners of the concave space (recess) where the plating that will become the electroformed product is grown (see, for example, Patent Document 1).

[0008] The technology proposed in Patent Document 1 places a conductive hardener at the corners of the recess, making not only the bottom surface of the electroforming mold but also part of the adjacent side surface conductive, thereby making it possible to form inclined surfaces or round the corners of the underside of the electroformed product. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 4530263 Summary of the Invention [Problem to be solved by the invention]

[0010] However, in the above-mentioned proposed technique, when the width of the opening of the recess in the electroforming mold is narrow and the depth of the recess is deep, which is a high aspect ratio, it is difficult to manually place the hardener accurately at the corners of the bottom of the recess, and it is also difficult to automate the process using a device instead of manually. Furthermore, when a conductive seed metal is formed as the starting point of plating, plating grows faster in the seed metal formed on the side wall close to the anode than in the conductive hardener at the corners of the bottom of the recess, and there is a risk of unnecessary cavities (voids) being formed inside the electroformed product.

[0011] The present invention has been made in consideration of the above circumstances, and aims to provide a method for manufacturing electroformed products and watch parts that can produce electroformed products having inclined surfaces (including rounded corners) on the corners of their underside, or electroformed products having an inclined surface on the outer periphery of their upper side, without manual labor, with high precision, and without forming voids. [Means for solving the problem]

[0012] The first aspect of the present invention is a method for manufacturing an electroformed product, which comprises forming an insulator layer corresponding to the shape of an electroformed product on a conductive substrate, sputtering an area of ​​the substrate where the substrate is exposed and where the insulator layer is not formed to scatter a conductive material from the substrate and adhere the scattered conductive material to a side surface of the insulator layer, depositing a metal by wet plating from the conductive material adhered to the substrate and the side surface in the area where the insulator layer is not formed to form the electroformed product, and removing the insulator layer to manufacture the electroformed product.

[0013] The second aspect of the present invention is a method for manufacturing an electroformed product, which includes forming an insulator layer corresponding to the shape of an electroformed product on a conductive substrate, applying wet plating to areas of the substrate where the substrate is exposed and where the insulator layer is not formed, forming a conductive sacrificial layer on the exposed substrate, sputtering the formed sacrificial layer to scatter conductive material from the sacrificial layer and attaching the scattered conductive material to sides of the insulator layer, depositing metal from the sacrificial layer and the conductive material attached to the sides in the areas where the insulator layer is not formed by wet plating to form the electroformed product, and removing the insulator layer to manufacture the electroformed product.

[0014] A third aspect of the present invention is a watch part as an electroformed product produced by the method for producing an electroformed product according to the present invention. Effect of the Invention

[0015] The manufacturing method of electroformed products and watch parts according to the present invention can provide a manufacturing method of electroformed products that can manufacture electroformed products having inclined surfaces (including rounded corners) on the corners of the lower surface and electroformed products having inclined surfaces on the outer periphery of the upper surface without manual labor, with high accuracy, and without forming voids. In particular, when the present invention manufactures a plurality of electroformed products simultaneously, it is possible to form inclined surfaces (including rounded corners) on all of the plurality of electroformed products at the same time, which improves manufacturing efficiency compared to the case where inclined surfaces are formed on the corners of each individual electroformed product. [Brief description of the drawings]

[0016] [Figure 1] 1A to 1C are cross-sectional views showing schematic steps of one embodiment of a method for producing an electroformed product (production method), illustrating a step of forming a photoresist layer and a step of exposing the photoresist layer. [Diagram 2] FIG. 2 is a cross-sectional view showing a schematic diagram of steps in one embodiment of a method for producing an electroformed product (production method), showing a development step and a sputtering step of a conductive layer. [Diagram 3] 3 is an enlarged view showing the details of part A in the lower part of FIG. [Figure 4] 1A to 1C are cross-sectional views showing a schematic diagram of steps in one embodiment of a method for producing an electroformed product (production method), illustrating a step of forming a sacrificial layer. [Diagram 5] 1A to 1C are cross-sectional views showing schematic steps of an embodiment of a method for producing an electroformed product (production method), illustrating an electroforming step and a grinding step. [Figure 6] 1A to 1C are cross-sectional views each showing a schematic diagram of a process of one embodiment of a method for producing an electroformed product (production method), illustrating a separation process of the electroformed product. [Figure 7] 1 is a cross-sectional view showing a schematic diagram of a process according to Modification 1 of Embodiment 1, illustrating an additional plating process. [Figure 8] 1A to 1C are cross-sectional views illustrating the steps of Variation 1 of Embodiment 1, showing an electroforming step and a photoresist layer removal step. [Figure 9] 10A to 10C are cross-sectional views illustrating a process of removing a portion of a sacrificial layer according to Modification 1 of Embodiment 1. [Figure 10] 10 is an enlarged view showing the details of part B in FIG. 9. FIG. [Figure 11] 10A to 10C are cross-sectional views illustrating the steps of removing a portion of the sacrificial layer in the first modified example. [Figure 12] 11A to 11C are cross-sectional views illustrating the steps of the second modified example, showing an electroforming step, a photoresist layer removing step, and a separation step of the electroformed product. [Figure 13] FIG. 11 is a cross-sectional view showing a manufacturing process of the modified example 2 in which a step of providing a phosphorescent paint is added, and shows a separation step of the electroformed product. [Figure 14] 13A to 13C are cross-sectional views illustrating the steps of forming a sacrificial layer in the third modification. [Figure 15] 13A to 13C are cross-sectional views illustrating the steps of the third modification, showing a sputtering step of a sacrificial layer. [Figure 16] 16 is an enlarged view showing the details of part C in FIG. 15. FIG. [Figure 17] 11A to 11C are cross-sectional views illustrating the steps of the third modified example, showing an electroforming step, a photoresist layer removing step, and a separation step of the electroformed product. [Figure 18] FIG. 13 is a cross-sectional view showing a schematic process of Modification 4, illustrating a process for producing an electroformed body in which a plurality of electroformed pieces grow above the upper surface of the insoluble portion and are connected by connecting parts. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a method for manufacturing an electroformed product according to the present invention and a watch component manufactured by the method for manufacturing an electroformed product will be described as follows with reference to the drawings.

[0018] <Embodiment 1> Figures 1 to 6 are cross-sectional views showing the steps of one embodiment (embodiment 1) of a method (manufacturing method) for producing an electroformed product 100, with Figure 1 showing the steps of forming a photoresist layer and exposing, Figure 2 showing the steps of developing and sputtering a conductive layer, Figure 4 showing the step of forming a sacrificial layer, Figure 5 showing the steps of electroforming and grinding, and Figure 6 showing the step of separating the electroformed product. Figure 3 is an enlarged view showing the details of part A in the lower part of Figure 2.

[0019] The method for manufacturing the electroformed product 100 shown in FIGS. 1 to 6 is one embodiment of the method for manufacturing an electroformed product according to the present invention.

[0020] First, a conductive substrate 10 shown in the upper part of Fig. 1 is prepared. The substrate 10 is a substrate body 11 on which a conductive film (conductive layer) 12 having conductivity is formed. The substrate body 11 may or may not have conductivity. When the substrate body 11 has conductivity, the substrate 10 may be composed of only the substrate body 11 without the conductive layer 12.

[0021] The substrate body 11 in this embodiment is made of, for example, silicon (Si) that does not have electrical conductivity. The substrate 10 has a configuration in which a conductive layer 12 is formed on an upper surface 11a of the substrate body 11 (the surface 11a on the side on which a photoresist layer 20 described later is laminated).

[0022] The conductive layer 12 in this embodiment is made of, for example, titanium (Ti). Note that the conductive layer 12 is not limited to titanium and may be made of other conductive materials.

[0023] (Photoresist layer formation process) Next, as shown in the middle of FIG. 1, a photoresist layer 20 (insulating layer) is laminated on the substrate 10. The photoresist layer 20 is formed on the conductive layer 12 of the substrate 10. The photoresist layer 20 may be a positive resist in which the parts irradiated with ultraviolet light (ultraviolet light) become soluble parts and the parts not irradiated become insoluble parts, or a negative resist in which the parts irradiated with ultraviolet light become insoluble parts and the parts not irradiated become soluble parts. The photoresist layer 20 in this embodiment is a negative resist.

[0024] (Exposure process) Next, as shown in the lower part of FIG. 1, a photomask 90 is placed on the surface (upper surface) side of the photoresist layer 20, and ultraviolet light L is irradiated onto the photoresist layer 20 from above through the photomask 90.

[0025] The photomask 90 has an optical pattern composed of light-transmitting portions 91 that transmit the ultraviolet light L and light-shielding portions 92 that do not transmit the ultraviolet light L. The optical pattern of the photomask 90 is formed corresponding to the shape of the electroformed product 100 to be manufactured.

[0026] (Development process) When ultraviolet light L is irradiated through the photomask 90, the portion of the photoresist layer 20 below the light-transmitting portion 91 becomes an insoluble portion 21 due to irradiation with the ultraviolet light L, and the portion below the light-shielding portion 92 becomes a soluble portion 22 due to not being irradiated with the ultraviolet light L. Then, as shown in the upper part of Fig. 2, the soluble portion 22 is removed by the development process to become a hollow portion 23 (recess), and the insoluble portion 21 remains, exposing the substrate 10. The hollow portion 23 and the insoluble portion 21 form a mold in which a pattern for manufacturing an electroformed product 100 is formed.

[0027] When the photoresist layer 20 is a positive resist, the light-shielding portions 92 form insoluble portions in the photoresist layer 20, and the light-transmitting portions 91 form soluble portions in the photoresist layer 20, in contrast to the above.

[0028] (Sputtering process of conductive layer) Next, as shown in the lower part of Figure 2, for a mold on which a pattern is formed by hollow portions 23 and insoluble portions 21 on substrate 10, conductive layer 12 of substrate 10 is negatively charged, and a plasma treatment is performed in which oxygen gas is introduced in a vacuum region to cause the sputtering phenomenon.

[0029] 3, the oxygen gas plasma collides with the conductive layer 12 in the cavity 23, scattering particles of the material (conductive material) of the conductive layer 12 from the conductive layer 12, and the particles of the material scattered from the conductive layer 12 form the conductive layer 12a attached to the side surface 21a of the insoluble portion 21 facing the cavity 23. The conductive layer 12a is formed from the lowermost part of the side surface 21a that contacts the conductive layer 12 to a predetermined height range.

[0030] In the case of the above-mentioned oxygen gas, for example, the sputtering phenomenon can be generated by the RIE (Reactive Ion Etching) method at a power of 110 [W] or more at a pressure of 16 [Pa]. When argon gas is introduced instead of oxygen gas, the sputtering phenomenon can also be generated by the RIE method at a pressure of 16 [Pa] and a power of 60 [W] or more.

[0031] In this embodiment, when oxygen gas is introduced into the plasma treatment instead of argon gas, it is possible to ash organic matter adhering to the surface of the conductive layer 12, and this is preferable when performing an ashing process at the same time. Note that ashing of organic matter is generally performed by the PE (plasma etching) method which does not involve sputtering, but the RIE method allows ashing without sputtering by keeping the output low.

[0032] (Sacrificial layer formation process) Next, as shown in the upper part of Fig. 4, the mold on which the conductive layer 12a shown in Fig. 3 is formed is subjected to wet plating in which the conductive layer 12 is connected to the negative electrode (-), thereby forming a conductive sacrificial layer 30 at the bottom of the cavity 23 as shown in the lower part of Fig. 4. For example, gold (Au) plating can be applied as the wet plating. The sacrificial layer 30 is not limited to gold plating, and plating with other conductive materials such as copper (Cu) plating or nickel (Ni) plating can also be applied. However, since the sacrificial layer 30 needs to be selectively dissolved with respect to the electroformed product 100, it is desirable that the sacrificial layer 30 be made of a material different from that of the electroformed product 100.

[0033] However, when a finishing film (coating) is formed on the surface of the electroformed object 100 using a material different from the material of the electroformed object 100, the electroformed object 100 is protected by the finishing film, so the sacrificial layer 30 can be formed using the same material as the electroformed object 100. In addition, when the materials are the same, selective dissolution is not possible, but by overlaying a sacrificial layer made of a different material on the sacrificial layer 30 or applying a release agent to the sacrificial layer 30, it becomes possible to distinguish the sacrificial layer made of a different material or the release agent from the electroformed object 100 and selectively dissolve them.

[0034] Here, the sacrificial layer 30 is formed flat with the conductive layer 12 as a starting point at the bottom of the cavity 23, and is formed with the conductive layer 12a as a starting point at the portion in contact with the side surface 21a of the insoluble portion 21. As a result, as shown in the lower part of Fig. 4, at a corner C which is the boundary between the conductive layer 12 at the bottom and the conductive layer 12a at the side surface 21a, the sacrificial layer 30 grown upward from the conductive layer 12 and the sacrificial layer 31 grown laterally or obliquely upward from the conductive layer 12a overlap with each other to form an inclined surface 32 (including a rounded curved surface) filling the corner C.

[0035] (Electroforming process) Next, by performing electroforming on the mold on which the sacrificial layer 30 has been formed, as shown in the upper part of Figure 5, a metal such as nickel precipitates and grows in the cavity 23 starting from the sacrificial layer 30 including the inclined surface 32, and an electroformed product 100 of a metal such as nickel that corresponds to the shape of the cavity 23 is formed.

[0036] (Grinding process) In the electroforming process, the electroformed product 100 is grown to protrude above the upper surface 21b of the insoluble portion 21 as shown in the upper part of Fig. 5. When the portion of the electroformed product 100 protruding from the cavity 23 to the upper surface 21b of the insoluble portion 21 is not required, the upper part of the electroformed product 100 is ground so that the upper surface 100a of the electroformed product 100 is equal to or lower than the height position of the upper surface 21b of the insoluble portion 21 as shown in the lower part of Fig. 5. As a result, the electroformed product 100 is formed into a shape corresponding to the cavity 23. When grinding the upper surface 100a of the electroformed product 100 to a position lower than the upper surface 21b of the insoluble portion 21, not only the upper surface 100a of the electroformed product 100 is ground, but the upper surface 21b of the insoluble portion 21 is also ground as a whole.

[0037] Furthermore, if the growth of the electroformed object 100 is stopped at a position lower than the upper surface 21b of the insoluble portion 21 in the electroforming process, an inclined surface 10f can be formed on the outer peripheral edge of the upper surface 100a, as in the electroformed object 100 of the modified example 2 (see Figures 12 and 13) and the modified example 3 (see Figure 17) described below.

[0038] (Separation process of electroformed products) Next, as shown in the upper part of Figure 6, the insoluble portion 21 of the photoresist layer 20 of the mold is dissolved and removed, and further, as shown in the lower part of Figure 6, the sacrificial layer 30 is dissolved and removed, thereby separating the electroformed object 100 from the substrate 10 and obtaining an electroformed object 100 corresponding to the shape of the hollow portion 23.

[0039] In this way, the electroformed product 100 manufactured by the manufacturing method of the electroformed product 100 of this embodiment has corners 100e at the outer periphery of the lower surface which are formed by transferring the inclined surface 32 of the sacrificial layer 30, and is therefore formed as an inclined surface (including a rounded surface) that fills the corners C of the electroforming mold. Therefore, the corners 100e of the electroformed product 100 formed as inclined surfaces have less sharpness than the corners of an electroformed product formed without filling the corners C with the sacrificial layer 30.

[0040] Furthermore, the manufacturing method for the electroformed product 100 of this embodiment does not require the manual operation of placing a conductive hardener or the like at the corners C of the cavity 23 using a microsyringe or pipette in the electroforming process, so that the manufacturing process can be automated and the electroformed product 100 having inclined surfaces (including rounded corners) at the corners 100e of the underside can be manufactured with high accuracy and reproducibility. Furthermore, the manufacturing method for the electroformed product 100 of this embodiment can also prevent unnecessary cavities (voids) from being formed inside the electroformed product 100 in the electroforming process.

[0041] In this embodiment, when multiple cavities 23 are formed as an electroforming mold, multiple electroformed objects 100 having inclined surfaces (including rounded surfaces) at the corners 100e of their undersides corresponding to the number of cavities 23 can be simultaneously manufactured, thereby improving manufacturing efficiency compared to the case where multiple electroformed objects 100 having inclined surfaces (including rounded surfaces) at the corners 100e of their undersides are manufactured individually.

[0042] <Variation 1> In the above-mentioned first embodiment, an electroformed product 100 is manufactured in which nickel, the material of electroforming, is exposed on the surface as it is. However, the manufacturing method of an electroformed product according to the present invention can be applied to the manufacturing method of an electroformed product in which an electroformed product 100 whose surface is coated with a finishing film 40 is manufactured as follows. The manufacturing method of this modified example 1 is modified example 1 in which a part of the manufacturing process of the first embodiment is modified. Figs. 7 to 11 are cross-sectional views showing the process of modified example 1, Fig. 7 shows an additional plating process, Fig. 8 shows an electroforming process and a photoresist layer removal process, Fig. 9 shows a process of removing a part of the sacrificial layer, and Fig. 11 shows a process of removing a part of the sacrificial layer. Fig. 10 is an enlarged view showing the details of part B in Fig. 9.

[0043] (Additional plating process) That is, in the manufacturing method of the electroformed product 100 of the first modification, after the step of forming the sacrificial layer 30 shown in FIG. 4 and before the electroforming step, as shown in the upper part of FIG. 7, wet plating is performed on the mold on which the sacrificial layer 30 is formed, with the conductive layer 12 connected to the negative electrode (-), to form a conductive additional plating layer 41 on the sacrificial layer 30, as shown in the lower part of FIG. 7. The wet plating in the step of forming the additional plating layer 41 (additional plating step) can be made of a material different from that of the sacrificial layer 30, for example, copper (Cu) plating. The additional plating layer 41 is not limited to copper plating, and may be made of a material different from that of the sacrificial layer 30, and is preferably made of the same material as the conductive layer 12. In the manufacturing method of the electroformed product 100 of the first modification, the plating layer 41 may be formed in a plurality of layers.

[0044] In the manufacturing method of the electroformed product 100 of the first modification, the plating layer 41 may be formed by dry plating. In the manufacturing method of the electroformed product 100 of the first modification, an ion plating method, a vacuum sputtering method, a vacuum deposition method, or the like can be used as the dry plating. When such dry plating is used, in the manufacturing method of the electroformed product 100 of the first modification, the plating layer 41 can be deposited also on the side surface 21a.

[0045] The plating layer 41 formed in the additional plating process conforms to the surface of the sacrificial layer 30, so that an inclined surface 42 conforming to the inclined surface 32 of the sacrificial layer 30 is formed on the outer peripheral edge of the lower surface, as shown in the lower part of Figure 7.

[0046] (Electroforming process) Next, by performing electroforming (electroforming) similar to that of embodiment 1 on the mold on which the additional plating layer 41 has been formed, as shown in the upper part of Figure 8, a metal such as nickel precipitates and grows in the cavity 23 starting from the additional plating layer 41, and an electroformed product 100 of a metal such as nickel that corresponds to the shape of the cavity 23 is formed.

[0047] (Photoresist layer removal process) 8, if necessary, at least the portion of the electroformed object 100 that protrudes higher than the upper surface 21b of the insoluble portion 21 is ground in the same manner as in the grinding step (see FIG. 5) in embodiment 1. Next, the insoluble portion 21 of the photoresist layer 20 is dissolved and removed from the mold, and the electroformed object 100 is formed on the substrate 10 with the sacrificial layer 30 and the plating layer 41 interposed therebetween, as shown in the lower part of FIG.

[0048] (Step of removing part of the sacrificial layer) 9 and 10, the outer peripheral edge of the sacrificial layer 30 (at least a part of the portion between the conductive layer 12a and the inclined surface 42 of the plating layer 41, which corresponds to the inclined surface 32) is removed. As a result, in the mold, a gap 30a corresponding to the portion of the sacrificial layer 30 where the inclined surface 32 was formed is formed between the plating layer 41 and the conductive layer 12a at the peripheral portion of the plating layer 41. In other words, the sacrificial layer 30 is recessed inward from the outer peripheral edge of the lower surface of the electroformed product 100, and the outer peripheral edge of the lower surface of the electroformed product 100 becomes an eaves that protrudes outward from the sacrificial layer 30.

[0049] (Film forming process) Next, as shown in the upper part of FIG. 11, a film forming process is performed on the mold in which the gap 30a is formed between the plating layer 41 and the conductive layer 12a. In the film forming process, the material of the conductive layer 12 is attached to the side surface 100b and the upper surface 100a of the electroformed product 100 by sputtering to form a film 43, and the plating layer 41 formed on the lower surface 100c of the electroformed product 100 is combined with the plating layer 41 formed on the lower surface 100c of the electroformed product 100, so that the entire surface of the electroformed product 100 is coated with a finishing film 40 consisting of the plating layer 41 and the film 43 including the inclined surface 42. The film 43 formed by sputtering does not cover the sacrificial layer 30 inside the eaves of the electroformed product 100, so that the sacrificial layer 30 is maintained in a state of communicating with the outside through the gap 30a. Note that the film forming process is not limited to the above-mentioned sputtering, and a film forming process of plating (dry plating or wet plating) including sputtering can be applied.

[0050] (Separation process of electroformed products) Next, the sacrificial layer 30 that is connected to the outside of the mold is dissolved and removed, and the electroformed object 100 coated with the finishing film 40 is separated from the substrate 10, and an electroformed object 100 coated with the finishing film 40 that corresponds to the shape of the cavity 23 is obtained.

[0051] In this way, in the electroformed product 100 manufactured by the manufacturing method of the electroformed product 100 of the first modification, the corners 100e at the outer periphery of the lower surface are formed as inclined surfaces (including rounded surfaces) that fill the corners C in the electroforming mold, because the corners 100e are formed as inclined surfaces by transferring the inclined surfaces 32 in the sacrificial layer 30. Therefore, in the electroformed product 100, the corners 100e formed as inclined surfaces have less sharpness than the corners of an electroformed product that are formed without filling the corners C with the sacrificial layer 30.

[0052] In variant example 1, when multiple cavities 23 are formed as an electroforming mold, multiple electroformed objects 100 having inclined surfaces (including rounded surfaces) at the corners 100e of their undersides corresponding to the number of cavities 23 can be simultaneously manufactured, thereby improving manufacturing efficiency compared to the case where multiple electroformed objects 100 having inclined surfaces (including rounded surfaces) at the corners 100e of their undersides are manufactured individually.

[0053] Furthermore, the manufacturing method of the electroformed product 100 of Modification 1 does not require the manual operation of placing a conductive hardener or the like at the corners C of the cavity 23 using a microsyringe or pipette in the electroforming process, so that the manufacturing process can be automated and the electroformed product 100 having inclined surfaces (including rounded corners) at the corners 100e of the underside can be manufactured with high accuracy and reproducibility. Furthermore, the manufacturing method of the electroformed product 100 of Modification 1 can also prevent unnecessary cavities (voids) from being formed inside the electroformed product 100 in the electroforming process.

[0054] Furthermore, in the manufacturing method of the first modification, by removing a part of the sacrificial layer 30 to form a gap 30a between the conductive layer 12a and the plating layer 41, it is possible to prevent the film 43 from covering the entire periphery of the sacrificial layer 30 when sputtering is performed in the (film formation step). Therefore, since the entire periphery of the sacrificial layer 30 is not covered by the film 43, it is possible to prevent the film 43 from hindering dissolution of the sacrificial layer 30 when dissolving the sacrificial layer 30 in the (electroformed product separation step).

[0055] Furthermore, the electroformed product 100 obtained by the manufacturing method of variant example 1 has its entire surface coated with the finishing film 40, which simplifies the process compared to a manufacturing process in which the electroformed product 100 is separated from the substrate 10 and then the finishing film 40 is coated in a separate process.

[0056] When the electroformed product 100 manufactured by the manufacturing method of the above-mentioned modification is used as a mold for molding a resin product, for example, the mold needs to be hard and have low abrasion resistance in order to withstand repeated use. Therefore, when the electroformed product 100 is used as a mold, it is preferable that the finishing film 40 is made of DLC (Diamond-Like Carbon), which is hard and has low abrasion resistance.

[0057] <Variation 2> The above-mentioned first embodiment has a step of forming a sacrificial layer 30 in the cavity 23 after the sputtering step of the conductive layer 12 (see Figs. 2 and 3), but the manufacturing method of the electroformed product according to the present invention can apply the following manufacturing method for manufacturing an electroformed product 100 having an inclined surface on the outer peripheral edge of the upper surface without forming the sacrificial layer 30. This manufacturing method is a part of the manufacturing method of the first embodiment, and is a second modification of the first embodiment. Fig. 12 is a cross-sectional view showing the steps of the second modification, and shows the electroforming step, the photoresist layer removal step, and the electroformed product separation step. Fig. 13 is a cross-sectional view showing the manufacturing method of the second modification with the addition of a step of providing a phosphorescent paint, and shows the electroformed product separation step.

[0058] (Electroforming process) That is, in the manufacturing method of the electroformed product 100 of the modified example 2, after the sputtering process of the conductive layer 12 shown in Figures 2 and 3, the process of forming the sacrificial layer 30 shown in Figure 4 is not performed, and electroformation is performed in the same manner as the electroformation process shown in Figure 5, so that, as shown in the upper part of Figure 12, a metal such as nickel is precipitated and grown in the cavity 23 starting from the conductive layers 12, 12a, thereby forming an electroformed product 100 of a metal such as nickel that corresponds to the shape of the cavity 23.

[0059] Here, the electroformed product 100 is formed by growth starting from the conductive layers 12, 12a, and therefore the upper surface 100a of the electroformed product 100 on the inside of the outer circumferential edge portion 100f that contacts the side surface 21a of the insoluble portion 21 is formed flat starting from the conductive layer 12. On the other hand, the outer circumferential edge portion 100f is formed starting from the conductive layer 12a that extends vertically along the conductive layer 12 and the side surface 21a, and therefore is formed inclined so as to rise higher than the inner flat portion as it approaches the side surface 21a.

[0060] Furthermore, in the electroforming process in variant example 2, by terminating the electroforming process before the upper surface 100a of the portion inside the outer peripheral edge portion 100f reaches the upper surface 21b of the insoluble portion 21, the outer peripheral edge portion 100f is formed on the upper surface of the electroformed object 100 as an inclined surface that is higher than the upper surface 100a of the flat portion, and a recess 100g that is recessed inward can be formed on the upper surface.

[0061] (Photoresist layer removal process) Thereafter, the insoluble portion 21 of the photoresist layer 20 is dissolved and removed, and the mold is in a state where an electroformed product 100 is formed on the substrate 10, as shown in the middle part of FIG.

[0062] In this way, the electroformed product 100 fixed to the substrate 10 can be used as a mold to manufacture a resin product having a shape that is an inverse of the shape of the electroformed product 100, for example, by pressing the electroformed product 100 against a resin material. In this case, only the shape of the recess 100g formed on the upper surface of the electroformed product 100 may be used as the mold.

[0063] (Separation process of electroformed products) On the other hand, when the electroformed object 100 is used as a part rather than as a mold, the conductive layers 12, 12a are removed by dissolving, so that the electroformed object 100 is separated from the substrate 10, as shown in the lower part of Figure 12, and the outer peripheral edge portion 100f of the upper surface is formed as an inclined surface, thereby producing an electroformed object 100 having a recess 100g.

[0064] The manufacturing method of the electroformed product 100 of the second modification does not require the manual operation of placing a conductive hardener or the like at the corners C of the cavity 23 using a microsyringe or pipette in the electroforming process, and therefore can automate the manufacturing process and can manufacture an electroformed mold or electroformed product 100 in which the outer peripheral edge 100f of the upper surface is formed as an inclined surface with high precision and high reproducibility. Furthermore, the manufacturing method of the electroformed product 100 of the second modification can also prevent unnecessary cavities (voids) from being formed inside the electroformed product 100 in the electroforming process.

[0065] In the manufacturing method of the electroformed product 100 of the second modification, a luminous paint is placed in the recess 100g on the upper surface of the electroformed product 100 as shown in the upper part of Fig. 13 while the electroformed product 100 is fixed to the substrate 10 as shown in the middle part of Fig. 12, and after the luminous paint is cured, the conductive layers 12, 12a are dissolved and removed, thereby separating the electroformed product 100 from the substrate 10, and the electroformed product 100 with the luminous paint provided in the recess 100g is obtained. Such an electroformed product 100 can be used, for example, as a hand of a watch provided with luminous paint.

[0066] <Variation 3> The above-mentioned embodiment 1 has a step of forming the sacrificial layer 30 in the cavity 23 after the sputtering step of the conductive layer 12 (see Figs. 2 and 3), but the manufacturing method of the electroformed product according to the present invention sputters the sacrificial layer 30 instead of sputtering the conductive layer 12, and attaches the sacrificial layer 30 to the side surface 21a of the insoluble portion 21. This manufacturing method is a modified example 3 of embodiment 1 in which a part of the manufacturing process of embodiment 1 is changed. Figs. 14 to 17 are cross-sectional views that typically show the process of modified example 3, where Fig. 14 shows the process of forming the sacrificial layer 30, Fig. 15 shows the process of sputtering the sacrificial layer 30, and Fig. 17 shows the electroforming process, the process of removing the photoresist layer, and the process of separating the electroformed product. Fig. 16 is an enlarged view showing the details of part C in Fig. 15.

[0067] (Sacrificial layer formation process) In the manufacturing method of the electroformed product 100 of the third modification, the mold in which the cavity 23 is formed as shown in the upper part of Fig. 2 is subjected to wet plating with the conductive layer 12 connected to the negative electrode (-) as shown in the upper part of Fig. 14 without performing the sputtering process shown in the lower part of Fig. 2. As a result, a sacrificial layer 30 is formed at the bottom of the cavity 23 of the mold as shown in the lower part of Fig. 4. For example, gold (Au) plating can be used as in the first embodiment for the wet plating. The sacrificial layer 30 is not limited to gold plating, and plating of other materials such as copper (Cu) plating or nickel (Ni) plating can also be used, but the material must be different from that of the electroformed product 100.

[0068] (Sacrificial layer sputtering process) Next, as shown in FIG. 15, the conductive layer 12 of the substrate 10 is negatively charged with respect to the sacrificial layer 30, and a sputtering phenomenon is caused to occur by plasma treatment in which argon (Ar) gas is introduced in a vacuum region.

[0069] 16, the argon gas plasma collides with the sacrificial layer 30 in the cavity 23, causing particles of the material of the sacrificial layer 30 (conductive material) to fly out from the sacrificial layer 30, and the particles of the material that fly out from the sacrificial layer 30 form a sacrificial layer 31 attached to the side surface 21a of the insoluble part 21 facing the cavity 23. The sacrificial layer 31 is formed from the lowermost part of the side surface 21a adjacent to the sacrificial layer 30 to a predetermined height range.

[0070] In the case of the above-mentioned argon gas, the sputtering phenomenon can be generated, for example, at a pressure of 16 [Pa] and an output of 60 [W] or more by the RIE method.

[0071] (Electroforming process) Next, by performing electrocasting on the mold on which the sacrificial layers 30, 31 are formed, as shown in the upper part of Figure 17, a metal such as nickel precipitates and grows in the cavity 23 starting from the sacrificial layers 30, 31, and an electrocast product 100 of a metal such as nickel that corresponds to the shape of the cavity 23 is formed.

[0072] Here, since the electroformed product 100 is formed by growth starting from the sacrificial layers 30 and 31, the upper surface 100a of the electroformed product 100 on the inside of the outer circumferential edge portion 100f that contacts the side surface 21a of the insoluble portion 21 is formed flat starting from the sacrificial layer 30. On the other hand, the outer circumferential edge portion 100f is formed starting from the sacrificial layer 30 and the sacrificial layer 31 that extends vertically along the side surface 21a, so that it is formed inclined so as to rise higher than the inner flat portion as it approaches the side surface 21a.

[0073] Furthermore, in the electroforming process in variant example 3, by terminating the electroforming process before the upper surface 100a of the portion inside the outer peripheral edge portion 100f reaches the upper surface 21b of the insoluble portion 21, the outer peripheral edge portion 100f is formed on the upper surface of the electroformed object 100 as an inclined surface that is higher than the upper surface 100a of the flat portion, and a recess 100g that is recessed inward can be formed on the upper surface.

[0074] (Photoresist layer removal process) Thereafter, the insoluble portion 21 of the photoresist layer 20 is dissolved and removed, and the mold is in a state where an electroformed product 100 is formed on the substrate 10, as shown in the middle part of FIG.

[0075] In this way, the electroformed object 100 that remains fixed to the substrate 10 can be used as a mold for producing a resin product having a shape that is the inverse of the shape of the electroformed object 100 by pressing it against a resin material or the like, similar to the electroformed object 100 produced in variant example 2.

[0076] (Separation process of electroformed products) On the other hand, when the electroformed object 100 is used as a part rather than as a mold, the sacrificial layers 30, 31 are removed by dissolving, so that the electroformed object 100 is separated from the substrate 10, as shown in the lower part of Figure 17, and the outer peripheral edge portion 100f of the upper surface is formed as an inclined surface, thereby producing an electroformed object 100 having a recess 100g.

[0077] The manufacturing method of the electroformed product 100 of the third modification does not require the manual operation of placing a conductive hardener or the like at the corners C of the cavity 23 using a microsyringe or pipette in the electroforming process, and therefore can automate the manufacturing process and manufacture, with high accuracy and reproducibility, an electroformed mold or an electroformed product 100 in which the outer peripheral edge 100f of the upper surface is formed as an inclined surface. Furthermore, the manufacturing method of the electroformed product 100 of the third modification can also prevent unnecessary cavities (voids) from being formed inside the electroformed product 100 in the electroforming process.

[0078] <Modification 4> In the above-described first embodiment, as shown in the upper part of Fig. 5, the electroformed object 100 grows above the upper surface 21b of the insoluble portion 21, and at least the portion of the electroformed object 100 protruding from the cavity 23 above the upper surface 21b of the insoluble portion 21 is removed in the grinding process, but a fourth modification may be used in which an electroformed object is manufactured by integrating a plurality of electroformed objects using the protruding portion. Fig. 18 is a cross-sectional view that illustrates a schematic process of the fourth modification, illustrating a process for manufacturing an electroformed object in which a plurality of electroformed objects 100 are connected together by the connecting portion 101, with the protruding portion being a connecting portion 101 formed when the plurality of electroformed objects 100 grow above the upper surface 21b of the insoluble portion 21.

[0079] In the manufacturing process of variant example 4, for example, in the case of a mold in which multiple cavities 23 are provided close to each other as shown in the upper part of Figure 18, the portion protruding from the cavity 23 onto the upper surface 21b of the insoluble portion 21 can function as a connecting portion 101 that connects the electroformed objects 100 grown in the multiple cavities 23.

[0080] Therefore, in a state where the insoluble portion 21, the sacrificial layer 30, and the conductive layer 12 of the mold are each removed by dissolution, it is possible to manufacture an integrated electroformed body in which a plurality of electroformed objects 100 are connected by connecting portions 101, as shown in the lower part of Fig. 18. The electroformed body manufactured in this way can be integrally manufactured, for example, into a medal in a chamfered state, with a shape to be embossed as an emblem on its surface. In addition, the electroformed body manufactured in this way can be used as a mold to manufacture a resin product having a shape that is the inverse of the shape of the electroformed body, for example, by pressing the electroformed body against a resin material.

[0081] In this way, in the electroformed product 100 manufactured by the manufacturing method of the electroformed product 100 of the fourth modification, the corners 100e at the outer periphery of the lower surface are formed as inclined surfaces (including rounded surfaces) that fill the corners C in the electroforming mold, because the corners 100e are formed as inclined surfaces by transferring the inclined surfaces 32 in the sacrificial layer 30. Therefore, in the electroformed product 100, the corners 100e formed as inclined surfaces have less sharpness than the corners of an electroformed product that are formed without filling the corners C with the sacrificial layer 30.

[0082] Furthermore, the manufacturing method of the electroformed product 100 of Modification 4 does not require the manual operation of placing a conductive hardener or the like at the corners C of the cavity 23 using a microsyringe or pipette in the electroforming process, so that the manufacturing process can be automated and the electroformed product 100 having inclined surfaces (including rounded corners) at the corners 100e of the underside can be manufactured with high accuracy and reproducibility. Furthermore, the manufacturing method of the electroformed product 100 of Modification 1 can also prevent unnecessary cavities (voids) from being formed inside the electroformed product 100 in the electroforming process.

[0083] Moreover, the manufacturing method of the electroformed product 100 of the fourth modification can simultaneously manufacture the inclined surfaces (including rounded corners) of the corners 100e of the lower surfaces of a plurality of electroformed products 100 constituted as part of an electroformed body.

[0084] In the first embodiment and each of the modifications, the sputtering process on the conductive layer 12 or the sacrificial layer 30 is not limited to plasma treatment, and for example, a blasting method, laser irradiation, etc. may also be applied. In the first embodiment and each of the modifications, the sputtering process may be performed in an atmosphere other than a vacuum.

[0085] In the first embodiment and each of the modified examples, the step of forming the sacrificial layer 30 may include mixing, for example, a brightener into the plating solution that will become the sacrificial layer 30. When the plating material is, for example, nickel, and wet plating is performed using a plating solution (nickel) that will become the sacrificial layer 30 mixed with a brightener such as saccharin or butynediol, the surface of the sacrificial layer 30 becomes smoother than when no brightener is mixed. Therefore, when the sacrificial layer 30 is removed after wet plating using a plating material solution mixed with a brightener, there is no need to add a process for smoothing the lower surface 100c of the electroformed product 100 that was in contact with the sacrificial layer 30, such as polishing. Note that when wet plating is performed without mixing a brightener into the plating solution that will become the sacrificial layer 30, when the plating material is, for example, copper, a matte-like unevenness is formed on the surface of the sacrificial layer 30.

[0086] In the manufacturing method of the electroformed product 100 of the first embodiment and each of the modified examples, the corners of the outer periphery of the upper surface 100a of the electroformed product 100 may be rounded or chamfered to form an obtuse angle. Note that in the manufacturing method of the electroformed product 100 of the first embodiment and each of the modified examples, the chamfering of the corners of the outer periphery of the upper surface of the electroformed product 100 can be performed, for example, after the step of removing the photoresist layer and before the step of separating the electroformed product 100 from the substrate 10, and in the modified example 1, it can be performed after the step of removing the photoresist layer and before the film formation step.

[0087] When chamfering the corners of the outer peripheral edge of the top surface of the electroformed product 100 at the timing described above, this chamfering can be performed within the process of the manufacturing method for the electroformed product 100 in embodiment 1 and each of the modified examples, making the process simpler than a manufacturing process in which chamfering is performed in a separate process after the electroformed product 100 is separated from the substrate 10.

[0088] The manufacturing method of the electroformed product according to the present invention, which has been described in detail in the first embodiment and each of the modified examples, does not require a separate barrel polishing of the manufactured electroformed product, and therefore can avoid tangling of the electroformed products and deformation of the electroformed products that would otherwise occur due to barrel polishing. Therefore, the manufacturing method of the electroformed product according to the present invention is particularly suitable for manufacturing, as electroformed products, parts having elongated portions such as second stop lever parts that may become tangled or deformed by barrel polishing, and thin parts such as vibration-resistant pressure spring parts that may become deformed.

[0089] In the manufacturing method of electroformed products according to the present invention, the electroformed product may be manufactured as a part itself, or the electroformed product may be manufactured as a mold (an object having the inverted shape of the other part) for manufacturing another part. [Explanation of symbols]

[0090] 10 Substrate 12 Conductive layer 20 Photoresist layer 21 Insoluble part 21a side 23 Cavity 30 Sacrificial Layer 100 Electroforming C Corner

Claims

1. An insulating layer corresponding to the shape of an electroformed object is formed on a conductive substrate; performing sputtering on an area of ​​the substrate where the insulating layer is not formed and the substrate is exposed, to cause a conductive material to be scattered from the substrate, and the scattered conductive material to adhere to a side surface of the insulating layer; forming the electroformed product by depositing metal from the conductive material attached to the substrate and the side surface in the region where the insulator layer is not formed by wet plating; The method for producing the electroformed product comprises removing the insulator layer to produce the electroformed product.

2. An insulating layer corresponding to the shape of an electroformed object is formed on a conductive substrate; performing sputtering on an area of ​​the substrate where the insulating layer is not formed and the substrate is exposed, to cause a conductive material to be scattered from the substrate, and the scattered conductive material to adhere to a side surface of the insulating layer; wet plating the exposed area of ​​the substrate to form a sacrificial layer on the exposed substrate and on the conductive material attached to the side of the insulator layer; Next, a metal is deposited from the sacrificial layer by another wet plating process to form the electroformed product; The method for producing the electroformed product comprises removing the insulator layer to produce the electroformed product.

3. After removing the insulator layer, a peripheral portion of the sacrificial layer is removed to form an overhang at a peripheral portion of a lower portion of the electroformed product, the overhang protruding outward beyond the sacrificial layer; Thereafter, a film is formed on the side and upper surfaces of the electroformed product by performing dry plating or wet plating. The method for producing an electroformed product according to claim 2 , further comprising the step of removing the sacrificial layer thereafter.

4. The insulator layer is formed in accordance with the shapes of the plurality of electroformed objects, 3. The method for producing an electroformed product according to claim 2, wherein the wet plating causes a plurality of electroformed products that overflow onto the upper surface of the insulator layer from an area where the insulator layer is not formed to be connected on the upper surface of the insulator layer to form an integrated electroformed product.

5. An insulating layer corresponding to the shape of an electroformed object is formed on a conductive substrate; wet plating an area of ​​the substrate where the insulator layer is not formed, to form a conductive sacrificial layer on the exposed substrate; sputtering the formed sacrificial layer to scatter a conductive material from the sacrificial layer, and attaching the scattered conductive material to a side surface of the insulator layer; forming the electroformed product by depositing metal from the conductive material attached to the sacrificial layer and the side surface in the region where the insulator layer is not formed by wet plating; The method for producing the electroformed product comprises removing the insulator layer to produce the electroformed product.

6. A watch part as an electroformed product produced by the method for producing an electroformed product according to any one of claims 1 to 4.

Images