Electroforming mold and method for manufacturing electroformed product using the electroforming mold

Abstract

To provide an electric mold that can be repeatedly used.SOLUTION: An electric mold 80 comprises a conductive substrate 10, an electric mold base 31, 36 arranged on the substrate 10, a conductive sacrificial layer 50 covering a surface of the substrate 10 or a surface of the electric mold base 31, 36 that faces a cavity 33 which is formed by the substrate 10 and the electric mold base 31, 36 and allows an electrically molded product 70 to be formed therein, and a resist layer 55 covering the sacrificial layer 50 except a part corresponding to a bottom surface 33a of the cavity 33.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to an electroforming mold and a method for manufacturing an electroformed product using the electroforming mold.

Background Art

[0002] For example, minute-shaped structures such as parts of a watch are manufactured by electroforming (a method for manufacturing, repairing, or replicating metal products by electroplating; hereinafter referred to as electroforming). Against such a background, in recent years, the application of the LIGA (Lithographie, Galvanoformung, Abformung) method, in which a photoresist layer is formed on a substrate and a pattern of a soluble portion and an insoluble portion is formed in the photoresist layer to manufacture an electroforming mold and produce a fine and highly accurate electroformed product, has been spreading.

[0003] Depending on the shape of the electroformed product, a plurality of resist layers may be formed. In this case, in the case of having a step between layers, by forming an intermediate conductive layer at the step portion, the growth rate of electroforming in the layer above the step can be increased (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in electroforming, particularly the LIGA method, a photoresist layer is used as a mold (electroforming mold) for an electroformed product, but in order to finally remove the electroformed product from the electroforming mold, it is necessary to dissolve the photoresist layer that is the electroforming mold. That is, every time an electroformed product is manufactured, it is necessary to remake the electroforming mold.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide an electroforming mold that can be repeatedly used and a method for manufacturing an electroformed product using the electroforming mold.

Means for Solving the Problems

[0007] A first aspect of the present invention is an electroforming mold including a conductive substrate, an electroforming mold base disposed on the substrate, and a sacrificial layer covering at least the surface of the substrate that faces a cavity portion formed by the substrate and the electroforming mold base, in which an electroformed product is formed, among the surfaces of the substrate and the electroforming mold base, and an insulating resist layer covering at least a part of the sacrificial layer except for at least a part of the portion corresponding to the bottom surface of the cavity portion.

[0008] A second aspect of the present invention is a method for manufacturing an electroformed product using an electroforming mold, in which plating is grown in the cavity portion by electroplating using the electroforming mold according to the present invention, and after the plating has grown until the cavity portion is filled, at least the sacrificial layer among the sacrificial layer and the resist layer is dissolved without dissolving the electroforming mold base, and the electroformed product made of the plating filling the cavity portion is separated from the electroforming mold.

Effects of the Invention

[0009] According to the electroforming mold of the present invention, it can be repeatedly used. Further, according to the method for manufacturing an electroformed product using the electroforming mold of the present invention, an electroformed product can be manufactured by repeatedly using the electroforming mold.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of an electroforming mold according to the present invention and a method for manufacturing an electroformed product using the electroforming mold will be described with reference to the drawings.

[0012] <Embodiment 1> Figs. 1 to 6 are cross-sectional views (Part 1 to Part 6) schematically showing the flow (indicated by arrows) of an example of a method (manufacturing method) for manufacturing an electroforming mold 80 which is a mold for manufacturing an electroformed product 70. The steps are in the order of Fig. 2 following Fig. 1, Fig. 3 following Fig. 2, Fig. 4 following Fig. 3, Fig. 5 following Fig. 4, and Fig. 6 following Fig. 5. Fig. 7 is a cross-sectional view schematically showing the flow (indicated by arrows) of an example of a method for manufacturing an electroformed product 70 using the electroforming mold 80 manufactured in the steps of Figs. 1 to 6.

[0013] The electroforming mold 80 is an embodiment of the electroforming mold according to the present invention, and the method for manufacturing the electroformed product 70 using this electroforming mold 80 is an embodiment of the method for manufacturing the electroformed product according to the present invention.

[0014] (Electroforming mold) First, an example of the method for manufacturing the electroforming mold 80 will be described with reference to Figs. 1 to 6. Note that the electroforming mold 80 is not limited to being manufactured by the manufacturing method shown in Figs. 1 to 6, and it may be manufactured by other manufacturing methods.

[0015] First, as shown in Fig. 1, a photoresist layer 20 is laminated on a substrate 10. The substrate 10 may be such that the substrate body 11 has conductivity, or when the substrate body 11 has no conductivity, for example, in the case of silicon, a conductive film (conductive layer) 12 having conductivity may be formed on the surface 11a of the substrate body 11 on which the photoresist layer 20 is laminated. When the substrate body 11 has conductivity, it is not necessary to form (laminate) the conductive film 12 on the substrate body 11. In this case, it corresponds to the substrate 10 in which the substrate body 11 has conductivity.

[0016] In the present embodiment, the conductive layer 12 is formed of, for example, a laminated film of titanium (Ti) and nickel (Ni) (titanium on the substrate body 11 side), but the conductive layer 12 is not limited to this material and may be any material having conductivity. Note that when the substrate body 11 has conductivity, the conductive layer 12 may not be provided.

[0017] The photoresist layer 20 may be a positive resist in which the portion irradiated with ultraviolet light (UV rays) is soluble and the portion not irradiated is insoluble, or a negative resist in which the portion irradiated with ultraviolet light is insoluble and the portion not irradiated is soluble. The photoresist layer 20 in the method for manufacturing the electroformed article 70 shown in FIG. 1 will be described on the premise that it is a negative resist.

[0018] Next, a photomask 90 is disposed on the surface (upper surface shown in the figure) side of the photoresist layer 20, and ultraviolet light L is irradiated onto the photoresist layer 20 from above through the photomask 90.

[0019] The photomask 90 has a pattern composed of a light-transmitting portion 92 that allows ultraviolet light L to pass through and a light-shielding portion 91 that does not allow ultraviolet light L to pass through. The pattern is formed corresponding to the contour shapes of the electroforming mold 80 and the electroformed article 70.

[0020] When ultraviolet light L is irradiated through the photomask 90, the portion below the light-transmitting portion 92 in the photoresist layer 20 becomes insoluble portion 22 by transmitting ultraviolet light L and being irradiated with ultraviolet light L, and remains even after development processing. On the other hand, the portion below the light-shielding portion 91 in the photoresist layer 20 becomes soluble portion 21 by blocking ultraviolet light L and not being irradiated with ultraviolet light L, and is removed by development processing as shown in FIG. 2.

[0021] In this way, the light-shielding portion 91 of the photomask 90 forms the soluble portion 21 in the photoresist layer 20, and the light-transmitting portion 92 forms the insoluble portion 22 in the photoresist layer 20. In the case where the photoresist layer 20 is a positive resist, on the contrary, the light-shielding portion 91 forms an insoluble portion in the photoresist layer 20, and the light-transmitting portion 92 forms a soluble portion in the photoresist layer 20.

[0022] As shown in FIG. 2, when the soluble portion 21 is removed by development processing, the portion where the soluble portion 21 existed becomes a cavity portion 23, and in this cavity portion 23, the substrate 10 is in an exposed state, and a pattern of this cavity portion 23 and the insoluble portion 22 is formed.

[0023] Then, in the electroplating process, in the cavity 23, a metal such as nickel is deposited and grown from the substrate 10, and a first layer electroforming mold base 31 made of a metal such as nickel corresponding to the contour shape of the cavity 23 is formed. The surface (the upper surface shown in the figure) of the first layer electroforming mold base 31 may be ground and polished flat.

[0024] After that, when the insoluble part 22 of the photoresist layer 20 is removed by another process, the part where the insoluble part 22 existed between the first layer electroforming mold bases 31 becomes the cavity 33.

[0025] Next, a photoresist layer 25 is formed so as to cover the first layer electroforming mold base 31 including the cavity 33 between the first layer electroforming mold bases 31. The photoresist layer 25 is made of the same material as the photoresist layer 20, but may be formed of a different material or may be a positive-type photoresist layer.

[0026] Next, a photomask 95 is disposed on the surface (the upper surface shown in the figure) side of the photoresist layer 25, and ultraviolet light L is irradiated onto the photoresist layer 20 through the photomask 95 from above.

[0027] The photomask 95 has a pattern composed of a light-transmitting part 97 that allows ultraviolet light L to pass through and a light-shielding part 96 that does not allow ultraviolet light L to pass through. The pattern is formed corresponding to the contour shapes of the electroforming mold 80 and the electroformed product 70.

[0028] When ultraviolet light L is irradiated through the photomask 95, in the photoresist layer 25, the part below the light-transmitting part 97 becomes an insoluble part 27 by transmitting ultraviolet light L and being irradiated with ultraviolet light L, and remains even after the development process. On the other hand, in the photoresist layer 25, the part below the light-shielding part 96 becomes a soluble part 26 by blocking ultraviolet light L and not being irradiated with ultraviolet light L, and is removed by the development process as shown in FIG. 3.

[0029] When the soluble portion 26 is removed by the developing process, the portion where the soluble portion 26 was present becomes a cavity portion 28 surrounded by the insoluble portion 27 and the substrate 10. In this cavity portion 28, the first electroforming mold base portion 31 is exposed, and a pattern of the cavity portion 28 and the insoluble portion 27 is formed.

[0030] Then, by the electroplating process, in the cavity portion 28, a metal such as nickel grows from the first electroforming mold base portion 31 connected to the conductive layer 12 of the substrate 10. As shown in FIG. 4, a second electroforming mold base portion 36 of a metal such as nickel corresponding to the contour shape of the cavity portion 28 is formed, and an electroforming mold laminated in two layers in the thickness direction is formed. Note that the surface (upper surface in the drawing) of the second electroforming mold base portion 36 may be ground and polished flat.

[0031] Thereafter, when the insoluble portion 27 of the photoresist layer 25 is removed by another process, the portions where the insoluble portion 27 was present between the first electroforming mold base portions 31 and between the second electroforming mold base portions 36 become cavity portions 33 surrounded by the electroforming mold base portions 31, 36 and the substrate 10.

[0032] Note that the second electroforming mold base portion 36 is laminated on the first electroforming mold base portion 31 in the thickness direction of the substrate 10 and is smaller than the first electroforming mold base portion 31. Therefore, at the boundary between the first electroforming mold base portion 31 and the second electroforming mold base portion 36, a stepped portion 34 where the first electroforming mold base portion 31 protrudes from the second electroforming mold base portion 36 is formed.

[0033] Next, as shown in FIG. 5, among the first electroforming mold base portion 31, the second electroforming mold base portion 36, and the surface (including the side surface) of the substrate, the surface facing the cavity portion 33 where the electroformed product 70 is formed is coated with a sacrificial layer 50. The sacrificial layer 50 is a layer that functions to separate the electroformed product 70 from the electroforming mold 80 by being dissolved later in place of the electroforming mold base portions 31 and 36, and is formed of, for example, copper (Cu) by sputtering (the thickness is, for example, 2 [μm]). Note that a titanium layer may be formed between the copper sacrificial layer 50 and the surface facing the cavity portion 33 where the electroformed product 70 is formed.

[0034] Since the sacrificial layer 50 serves as the starting point for electroforming the electroformed product 70, it is formed of a conductive material. The sacrificial layer 50 is not limited to copper. Since the sacrificial layer 50 is later dissolved in place of the electroforming mold bases 31, 36, it needs to be formed of a material that can be dissolved by a chemical different from that for the electroforming mold bases 31, 36. Therefore, the sacrificial layer 50 is formed of a material different from that of the electroforming mold bases 31, 36.

[0035] Although not shown in this embodiment, a copper layer may be uniformly formed thickly (for example, 2 [μm]) by electroless plating on the sacrificial layer 50. By forming the copper layer, when the sacrificial layer 50 is formed by electroless plating instead of sputtering, the thickness of the sacrificial layer 50 can be formed more uniformly, and the dimensional accuracy of the electroformed product 70 can be improved.

[0036] Next, using a metal mask (stencil mask) 98 in which an opening 99 is formed in a portion corresponding to the portion (the bottom surface 33a in contact with the conductive layer 12 of the substrate 10) of the sacrificial layer 50 that serves as the starting point for plating, particles 61 (for example, ferrite particles having a size of about 10 [μm]) are arranged on the bottom surface 33a that serves as the starting point for plating in the sacrificial layer 50. Specifically, by immersing in a solution 60 in which the particles 61 are dispersed, the particles 61 settle from the portion of the opening 99 to the bottom surface 33a, and the particles 61 can be arranged on the bottom surface 33a.

[0037] Next, the sacrificial layer 50 is coated with a resist layer 55. Specifically, a resist layer 55 of silicon (Si) is formed on the surface of the sacrificial layer 50 by sputtering. A titanium layer may be formed between the sacrificial layer 50 and the resist layer 55 to enhance the adhesion between the sacrificial layer 50 and the resist layer 55.

[0038] Here, at the bottom surface 33a where the particles 61 are interposed, the adhesion between the sacrificial layer 50 and the resist layer 55 laminated on the sacrificial layer 50 is lower than that of portions other than the bottom surface 33a. The resist layer 55 is non-conductive.

[0039] Therefore, as shown in FIG. 6, when the resist layer 55 is ultrasonically cleaned, the portion of the resist layer 55 laminated on the bottom surface 33a of the cavity 33, where the adhesion to the sacrificial layer 50 is relatively low due to the presence of the particles 61, is removed, and the sacrificial layer 50 is exposed.

[0040] That is, in the cavity 33 where the electroformed product 70 is formed, the sacrificial layer 50 having conductivity is exposed only in the portion corresponding to the bottom surface 33a of the cavity 33, and the portion of the sacrificial layer 50 other than the bottom surface 33a is covered with the non-conductive resist layer 55. Therefore, in the manufacturing method of forming the electroformed product 70 by electroplating in the cavity 33, plating can be grown only from the sacrificial layer 50 corresponding to the bottom surface 33a. Note that the portion of the sacrificial layer 50 exposed after removing the resist layer 55 in the portion corresponding to the bottom surface 33a may be a part or all of the portion corresponding to the bottom surface 33a.

[0041] Further, a part of the resist layer 55 corresponding to the side surface 33b of the cavity 33 adjacent to the portion corresponding to the bottom surface 33a of the cavity 33 may also be removed. That is, the resist layer 55 may be in a state of covering the range excluding a part of the portion corresponding to the side surface 55b as well as the portion corresponding to the bottom surface 33a of the sacrificial layer 50.

[0042] As a method for removing the resist layer 55 on the bottom surface 33a, instead of using the above-described particles 61, an aluminum film may be formed only on the bottom surface 33a by vacuum evaporation.

[0043] Since defects such as pinholes exist in the resist layer 55, the liquid for removing the aluminum film dissolves the aluminum through the defects, so that the resist layer 55 is peeled off (lifted off), and the resist layer 55 on the bottom surface 33a can be removed.

[0044] As other methods, the resist layer 55 on the bottom surface 33a may be removed by vacuum evaporation from an oblique direction, laser light irradiation, or the like.

[0045] Next, using a mask 65 having an opening 67 corresponding to the region of the step portion 34 formed at the boundary between the first electroforming mold base 31 and the second electroforming mold base 36, an intermediate conductive layer 45 is formed on the step portion 34 by vacuum evaporation. The intermediate conductive layer 45 is formed of, for example, the same nickel (or nickel with titanium in between) as the conductive layer 12.

[0046] By the manufacturing method as described above, the electroforming mold 80 of Embodiment 1 shown in FIG. 6 is manufactured. Here, the electroforming mold 80 includes a conductive substrate 10, a first electroforming mold base 31, a second electroforming mold base 36, a sacrificial layer 50 that covers the surface facing the cavity 33 for forming the electroformed article 70 among the surfaces of the substrate 10 and the electroforming mold bases 31 and 36, a resist layer 55 that covers portions other than the bottom surface 33a of the cavity 33 of the sacrificial layer 50, and an intermediate conductive layer 45 disposed on the step portion 34.

[0047] (Method for manufacturing an electroformed article) FIG. 7 is a cross-sectional view schematically showing an example of the process for manufacturing an electroformed article 70 using the electroforming mold 80. Next, an example of the method for manufacturing the electroformed article 70 using this electroforming mold 80 will be described with reference to FIG. 7. When electroplating nickel, for example, on the electroforming mold 80, a nickel electroformed article 70 grows from the sacrificial layer 50 exposed on the bottom surface 33a. When the electroformed article 70 fills the cavity 33 of the first electroforming mold base 31, the grown electroformed article 70 comes into contact with the intermediate conductive layer 45 of the step portion 34, and electricity flows through the intermediate conductive layer 45.

[0048] As a result, in the cavity 33 of the second electroforming mold base 36, plating grows from the electroformed article 70 that fills the cavity 33 of the first layer and the intermediate conductive layer 45, and the electroformed article 70 is formed so as to fill the cavity 33 of the second layer.

[0049] In this way, the plating for filling the cavity 33 of the second layer grows not only from the electroformed article 70 that fills the cavity 33 of the first layer but also from the intermediate conductive layer 45. Therefore, compared with an electroforming mold without the intermediate conductive layer 45, the time required to fill the cavity 33 of the second layer with plating can be shortened.

[0050] Next, after the electroformed product 70 is formed up to the second-layer cavity portion 33, the resist layer 55, the sacrificial layer 50, and the electroformed product 70 filling the second-layer cavity portion 33 are ground and polished flat so that the upper surface of the second-layer electroforming mold base 36 is exposed. Thereby, the sacrificial layer 50 serving as the boundary between the electroforming mold base 36 and the electroforming mold base 31 and the electroformed product 70 is exposed on the upper surface. Ideally, by completing the grinding and polishing up to the extent that the sacrificial layer 50 is exposed, the consumption of the electroforming mold base 36 can be suppressed.

[0051] Then, the electroformed product 70 is separated from the electroforming mold base 36 and the electroforming mold base 31 by dissolving the sacrificial layer 50 exposed on the upper surface. At this time, since the chemical used for dissolving the sacrificial layer 50 is selected as a chemical that has no influence on the electroforming mold bases 31 and 36, the electroforming mold bases 31 and 36 are not dissolved and remain as the electroforming mold bases 31 and 36 in the state shown in FIG. 4.

[0052] Therefore, by reusing the electroforming mold bases 31 and 36 in the state shown in FIG. 4 and forming the electroforming mold 80 in the processes shown in FIGS. 5 and 6, the electroforming mold bases 31 and 36 can be reused repeatedly.

[0053] Note that although the resist layer 55 and the intermediate conductive layer 45 remain on the surface of the electroformed product 70 separated from the electroforming mold 80, if there is no problem with the electroformed product 70, the resist layer 55 and the intermediate conductive layer 45 may be left on the electroformed product 70 as they are. On the other hand, when the resist layer 55 and the intermediate conductive layer 45 are unnecessary, a process for removing these resist layer 55 and intermediate conductive layer 45 may be added to the electroformed product 70 separately.

[0054] As described in detail above, the electroforming mold 80 of Embodiment 1 can be repeatedly used instead of being used up every time an electroformed product 70 is manufactured. Further, according to the method for manufacturing an electroformed product 70 using the electroforming mold 80 of the present embodiment, the electroformed product 70 can be manufactured by repeatedly using the electroforming mold 80.

[0055] Therefore, the method for manufacturing the electroformed article 70 using the electroforming mold 80 of the present embodiment can reduce the manufacturing cost of the electroformed article 70 as compared with the manufacturing method in which the electroforming mold is used up every time the electroformed article 70 is manufactured.

[0056] <Embodiment 2> In the electroforming mold 80 of the above-described Embodiment 1, on the entire surface of the surface of the substrate 10 and the surfaces of the electroforming mold bases 31 and 36 that faces the cavity 33 in which the electroformed article 70 is formed, which is formed by the substrate 1 and the electroforming mold bases 31 and 36, the conductive sacrificial layer 50 is formed. However, the electroforming mold according to the present invention is not limited to the one in which the conductive sacrificial layer 50 is formed on the entire surface of the surface facing the cavity 33.

[0057] That is, the conductive sacrificial layer 50 only needs to cover at least a part (a part or the entire surface of the bottom surface 33a) of at least the surface in contact with the substrate 10 (the bottom surface 33a of the cavity 33) among the surfaces facing the cavity 33 in which the electroformed article 70 is formed.

[0058] That is, since the conductive sacrificial layer 50 serves as a starting point for the growth of the electroformed article 70, it is necessary to be in contact with the substrate 10. Therefore, it is essential that the conductive sacrificial layer 50 is formed on a part of the bottom surface 33a of the cavity 33 and is in contact with the substrate 10.

[0059] On the other hand, the sacrificial layer 50 needs to separate the electroforming mold bases 31 and 36 from the electroformed article 70 by dissolving the sacrificial layer 50 itself. However, as the portion intervening between the electroforming mold bases 31 and 36 and the electroformed article 70, it is not necessary to have conductivity. That is, the portion intervening between the electroforming mold bases 31 and 36 and the electroformed article 70 does not need to be the conductive sacrificial layer 50, and may exhibit a function of separating the electroforming mold bases 31 and 36 from the electroformed article 70 by dissolving regardless of whether it has conductivity or not.

[0060] Therefore, the conductive sacrificial layer 50 only needs to cover at least a part (a part or the whole of the bottom surface 33a) of the bottom surface 33a of the cavity 33. Among the surfaces facing the cavity 33 where the electroformed product 70 is formed, for the portion intervening between the electroforming mold bases 31 and 36 and the electroformed product 70, excluding the part of the bottom surface 33a where the conductive sacrificial layer 50 is disposed, it may be formed of a non-conductive sacrificial layer.

[0061] Figs. 8 and 9 are cross-sectional views schematically showing an example of the process flow of manufacturing the electroforming mold 180 in which the portion intervening between the electroforming mold bases 31 and 36 and the electroformed product 70 is formed of a resist layer 55 that functions as a non-conductive sacrificial layer, showing the processes following the process flow shown in Figs. 1 to 4. Further, Fig. 10 is a cross-sectional view schematically showing an example of the process flow of manufacturing the electroformed product 70 using the electroforming mold 180 shown in Fig. 9.

[0062] The electroforming mold 180 of the present embodiment is manufactured by the manufacturing method shown in Figs. 1 to 4. As shown in Fig. 8, for the electroforming mold bases 31 and 36 formed on the substrate 10, the surface facing the cavity 33 where the electroformed product 70 is formed among the surface of the first-layer electroforming mold base 31, the second-layer electroforming mold base 36, and the surface (including the side surface) of the substrate is coated with an insulating resist layer 55 by a spray coating method. The spray coating method can thinly and uniformly apply the resist following the unevenness of the surface of the object to be coated.

[0063] The resist layer 55 is dissolved together with the sacrificial layer 50 formed later. Therefore, the resist layer 55 functions in the same manner as the sacrificial layer 50 in Embodiment 1. Note that the resist forming the resist layer 55 is, for example, a positive resist. Since the positive resist has higher solubility than the negative resist, it is more user-friendly than the negative resist when functioning as a sacrificial layer to be dissolved later.

[0064] Next, the photomask 195 is placed, and the resist layer 55 is exposed from above through the photomask 195. The photomask 195 is formed with a light-transmitting portion 196 that allows ultraviolet light L to pass through. The light-transmitting portion 196 is formed corresponding to the bottom surface 33a of the cavity portion 33, and by exposure to ultraviolet light L, the resist layer 55 on the bottom surface 33a exposed through the light-transmitting portion 196 is removed, and the substrate 10 is exposed at the bottom surface 33a.

[0065] Next, as shown in FIG. 9, using a mask 65 formed with an opening 67 corresponding to the region of the step portion 34 formed at the boundary between the first electroforming mold base 31 and the second electroforming mold base 36, an intermediate conductive layer 45 is formed on the step portion 34 by vacuum deposition. The intermediate conductive layer 45 is formed of, for example, the same nickel as the conductive layer 12 (or nickel with titanium in between).

[0066] Next, by an electroplating process, a sacrificial layer 50 of, for example, copper is formed on the substrate 10 exposed at the bottom surface 33a of the cavity portion 33.

[0067] By the manufacturing method as described above, the electroforming mold 180 of Embodiment 2 shown in FIG. 9 is manufactured. Here, the electroforming mold 180 includes a conductive substrate 10, a first electroforming mold base 31, a second electroforming mold base 36, and among the surfaces of the substrate 10 and the surfaces of the electroforming mold bases 31 and 36, the surface facing the cavity portion 33 where the electroformed product 70 is formed and in contact with the substrate 10 (the bottom surface 33a of the cavity 33) is covered with a conductive sacrificial In layer 50 coating.

[0068] On the other hand, in the electroforming mold 180, the portion intervening between the electroforming mold bases 31 and 36 and the electroformed product 70 is formed of an insulating resist layer 55 having no conductivity. This resist layer 55 dissolves together with the sacrificial layer 50 during the manufacturing process of the electroformed product 70 and functions as a sacrificial layer.

[0069] (Method for manufacturing an electroformed product) Next, an example of a method for manufacturing an electroformed product 70 using this electroforming mold 180 will be described with reference to FIG. 10. When electroplating nickel, for example, with the electroforming mold 180, an electroformed nickel product 70 grows from the sacrificial layer 50 formed on the bottom surface 33a. When the electroformed product 70 fills the cavity 33 of the first-layer electroforming mold base 31, the grown electroformed product 70 comes into contact with the intermediate conductive layer 45 at the stepped portion 34, and electricity flows through the intermediate conductive layer 45.

[0070] As a result, in the cavity 33 of the second-layer electroforming mold base 36, electroplating grows from the electroformed product 70 that fills the cavity 33 of the first layer and the intermediate conductive layer 45, and the electroformed product 70 is formed so as to fill the cavity 33 of the second layer.

[0071] In this way, the electroplating that fills the cavity 33 of the second layer grows not only from the electroformed product 70 that fills the cavity 33 of the first layer but also from the intermediate conductive layer 45. Therefore, compared with an electroforming mold in which the intermediate conductive layer 45 is not disposed, the time taken to fill the cavity 33 of the second layer with electroplating can be shortened.

[0072] Next, after the electroformed product 70 is formed up to the cavity 33 of the second layer, the resist layer 55 and the electroformed product 70 that fills the cavity 33 of the second layer are ground and polished flat so that the upper surface of the second-layer electroforming mold base 36 is exposed. Thereby, the resist sacrificial layer 50 that functions as a sacrificial layer and forms the boundary between the electroforming mold bases 36 and 31 and the electroformed product 70 is exposed on the upper surface.

[0073] Then, the electroformed product 70 is separated from the electroforming mold bases 36 and 31 by dissolving the resist layer 55 exposed on the upper surface and further dissolving the sacrificial layer 50 in contact with the substrate 10. At this time, since the chemicals used for dissolving the resist layer and the chemicals used for dissolving the sacrificial layer 50 are selected as chemicals that do not affect the electroforming mold bases 31 and 36, the electroforming mold bases 31 and 36 are not dissolved and remain as the electroforming mold bases 31 and 36 in the state shown in FIG. 4.

[0074] Therefore, by reusing the electroforming mold bases 31 and 36 in the state shown in FIG. 4 and forming the electroforming mold 180 in the processes shown in FIGS. 8 and 9, the electroforming mold bases 31 and 36 can be reused repeatedly.

[0075] Note that although the intermediate conductive layer 45 remains on the surface of the electroformed product 70 separated from the electroforming mold 180, if there is no problem with the electroformed product 70, the intermediate conductive layer 45 may be left on the electroformed product 70 as it is. On the other hand, when the intermediate conductive layer 45 is unnecessary, a process of removing the intermediate conductive layer 45 may be additionally performed on the electroformed product 70 separately.

[0076] As described in detail above, the electroforming mold 180 of Embodiment 2 can be repeatedly used instead of being used up every time an electroformed product 70 is manufactured. Also, according to the method for manufacturing an electroformed product 70 using the electroforming mold 180 of the present embodiment, the electroformed product 70 can be manufactured by repeatedly using the electroforming mold 180.

[0077] Therefore, the method for manufacturing an electroformed product 70 using the electroforming mold 80 of the present embodiment can reduce the manufacturing cost of the electroformed product 70 as compared with a manufacturing method in which the electroforming mold is used up every time an electroformed product 70 is manufactured.

[0078] The electroforming mold 80 of each of the above-described embodiments is manufactured in the processes shown in FIGS. 1 to 6, or is manufactured in the processes of FIGS. 1 to 4 and FIGS. 8 to 9. However, the electroforming mold according to the present invention is not limited to those manufactured by the manufacturing methods of the respective embodiments.

[0079] That is, the electroforming mold according to the present invention may have a configuration including a conductive substrate, an electroforming mold base disposed on the substrate, a conductive sacrificial layer covering at least the surface of the substrate (the bottom surface of the cavity portion) among the surfaces of the substrate and the electroforming mold base facing the cavity portion, and a resist layer covering the sacrificial layer except for the portion corresponding to the bottom surface of the cavity portion, and may be manufactured by any manufacturing method.

[0080] The electroforming mold 80 of each embodiment is a two-layer electroforming mold. However, the electroforming mold according to the present invention is not limited to two layers, and may be a single-layer mold or a mold having three or more layers.

[0081] Since the electroforming mold 80 of each embodiment is a two-layer electroforming mold, an intermediate conductive layer 45 is provided at a stepped portion 34 that is the boundary between the first-layer electroforming mold base 31 and the second-layer electroforming mold base 36. However, in an electroforming mold having only the electroforming mold base 31 of a single layer, the intermediate conductive layer may not be provided.

[0082] The electroforming mold 80 of each embodiment is formed by metal for the first-layer electroforming mold base 31 and the second-layer electroforming mold base 36. However, for the electroforming mold 80, it is sufficient that the bottom surface (a part of the surface of the substrate) of the cavity 33 that forms the electroformed product 70 is covered with a sacrificial layer, and the electroforming mold bases 31 and 36 do not necessarily have to be formed of metal.

[0083] Therefore, the electroforming mold bases 31 and 36 may be resin. Note that since the electroforming mold 80 with the electroforming mold bases 31 and 36 made of resin cannot be formed by electroplating in the electroplating process of the resin electroforming mold bases 31 and 36, it is necessary to form them by microfabrication techniques other than electroplating. In addition, the electroforming mold 80 with the electroforming mold bases 31 and 36 made of resin may be formed with the pattern using the aforementioned photoresist.

[0084] Since the electroforming mold 80 of each embodiment can grow plating only from the sacrificial layer 50 of the exposed bottom surface 33a, after the growth of plating in the first-layer cavity 33, which is narrower than the second-layer cavity 33, is completed, the growth of plating in the second-layer cavity 33 is started.

[0085] Therefore, if the resist layer 55 is used to form an electroforming mold that does not limit the exposed portion of the sacrificial layer 50 to only the bottom surface 33a, the growth of plating proceeds faster in the second-layer cavity 33, which is wider than the first-layer cavity 33, than in the first-layer cavity 33. In this case, before the first-layer cavity 33 is completely filled with plating, the second-layer cavity 33 may be filled with plating, and there is a possibility that a cavity may remain in the first-layer portion of the electroformed product 70.

[0086] In each embodiment, the electroforming mold 80 exposes the sacrificial layer 50 only to the bottom surface 33a of the cavity 33, so that plating can be grown from the first-layer cavity 33 to prevent a cavity from remaining in the first layer of the electroformed product 70.

[0087] In each embodiment, the sacrificial layer 50 of the electroforming mold 80 is formed of a material different from that of the electroforming mold bases 31 and 36. However, when only the sacrificial layer 50 can be dissolved without dissolving the electroforming mold bases 31 and 36, the sacrificial layer 50 may be formed of the same material as the electroforming mold bases 31 and 36.

Description of Reference Numerals

[0088] 10 Substrate 31, 36 Electroforming mold bases 33 Cavity 33a Bottom surface 50 Sacrificial layer 55 Resist layer 70 Electroformed product 80 Electroforming mold

Claims

1. A conductive substrate, An electroforming mold base disposed on the substrate, Among the surface of the substrate and the surface of the electroforming mold base, at least the surface in contact with the substrate among the surfaces facing the cavity where the electroformed product is formed, which is formed by the substrate and the electroforming mold base, a conductive sacrificial layer covering the surface, An insulating resist layer covering at least a part of the portion of the sacrificial layer corresponding to the bottom surface of the cavity, The electroforming mold base is formed in two or more layers in the thickness direction of the substrate and has a stepped portion between the layers, An electroforming mold in which a conductive intermediate conductive layer is formed on the resist layer covering the sacrificial layer at the stepped portion.

2. A conductive substrate, An electroforming mold base disposed on the substrate, Among the surface of the substrate and the surface of the electroforming mold base, at least the surface in contact with the substrate among the surfaces facing the cavity where the electroformed product is formed, which is formed by the substrate and the electroforming mold base, a conductive sacrificial layer covering the surface and having a function of separating the electroformed product from the electroforming mold by being dissolved in place of the electroforming mold base, An electroforming mold comprising an insulating resist layer covering at least a part of the portion of the sacrificial layer corresponding to the bottom surface of the cavity.

3. The sacrificial layer is formed covering also a part of the portion corresponding to the side surface of the cavity adjacent to the portion corresponding to the bottom surface of the cavity, The electroforming mold according to claim 2, wherein the resist layer covers the sacrificial layer excluding also a part of the portion corresponding to the side surface of the cavity adjacent to the portion corresponding to the bottom surface of the cavity.

4. The electroforming mold base is formed in two or more layers in the thickness direction of the substrate and has a stepped portion between the layers, The electroforming mold according to claim 2 or 3, wherein a conductive intermediate conductive layer is formed on the resist layer covering the sacrificial layer at the stepped portion.

5. Using the electroforming mold according to claim 1 or 2, growing plating in the cavity by electroplating, After the plating has grown until the cavity is filled, without dissolving the electroforming mold base, dissolving at least the sacrificial layer among the sacrificial layer and the resist layer to separate the electroformed product made of the plating filling the cavity from the electroforming mold, a method for manufacturing an electroformed product using an electroforming mold.

6. A method for manufacturing an electroformed article using an electroforming mold, the method comprising: a conductive substrate; an electroforming mold base disposed on the substrate; a cavity in which an electroformed article is formed, the cavity being formed by the substrate and the electroforming mold base, and facing at least the surface of the substrate or the surface of the electroforming mold base; a conductive sacrificial layer covering at least the surface of the substrate in contact with the substrate; and an insulating resist layer covering at least a part of the sacrificial layer except for at least a part of the portion corresponding to the bottom surface of the cavity. Growing plating in the cavity by electroplating. After the plating has grown until the cavity is filled, without dissolving the electroforming mold base, separating the electroformed article formed by the plating filling the cavity from the electroforming mold by dissolving at least the sacrificial layer among the sacrificial layer and the resist layer.

7. The method for manufacturing an electroformed article using an electroforming mold according to claim 5 or 6, wherein after separating the electroformed article from the electroforming mold, the resist layer is removed from the electroformed article.

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