Electroformed parts and their manufacturing methods

Abstract

The present invention provides a method for manufacturing a component in which two or more components are integrally formed, which is compact and capable of stably and accurately connecting each component. [Solution] The electroformed component 10 comprises a first structure 11 formed by depositing electroformed material and a second structure 12 connected to the first structure 11, wherein the second structure 12 is connected only to the side surface of the first structure 11 along the depositing direction. The connection surfaces of the first structure 11 and the second structure 12 may be configured such that the protrusions and recesses 11a and 12a provided on each structure engage with each other.

Description

Technical Field

[0001] The present invention relates to an electroformed part by an electroplating method and a method for manufacturing the same.

Background Art

[0002] Conventionally, in a movement of a wristwatch or the like, a part that engages with a gear and pushes the teeth of the gear to perform a feed operation of the gear has been used. Examples of such parts include a feed claw that rotates an index wheel of a wristwatch (see, for example, Patent Document 1). Parts such as feed claws are required to have excellent dimensional accuracy, slidability, wear resistance, hardness, etc., and are made of a metal member such as stainless steel, or in order to enhance wear resistance, a metal member having a hard member such as ruby disposed at a contact portion with another part has been used.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a part such as a feed claw is composed only of a single metal member such as stainless steel, wear occurs at a portion that contacts and slides with another part, and it is difficult to ensure reliability over a long period of time. Further, when a hard member such as ruby is disposed on a metal member, although wear is reduced, since each of the metal member and the hard member is minute, it is difficult to fix them by adhesion or the like, and since the fixing force of these parts itself is small, there is also a problem that the connection between the parts is unstable. Furthermore, when trying to achieve more stable fixing of the metal member and the hard member, it is difficult to miniaturize the parts.

[0005] <​In view of the above problems, the present invention aims to provide a method for manufacturing a component in which two or more members are integrally formed, which is compact and capable of stably connecting each member with high precision. [Means for solving the problem]

[0006] The electroformed component comprises a first structure formed by depositing electroformed material and a second structure connected to the first structure, wherein the second structure is connected only to the side surface of the first structure along the depositing direction. The side surface of the second structure connected to the first structure, and the side surface of the first structure connected to the second structure, may each have protrusions and recesses, and when the connection interface between the first structure and the second structure is viewed from above, the protrusions and recesses may be configured to engage with each other. Furthermore, the electroformed component may have a metal film covering the connection interface between the first structure and the second structure on the first structure and the second structure. Furthermore, the electroformed product may also be a component of a clock. In that case, the electroformed component is a feed pawl for engaging with a gear to rotate the gear, and the feed pawl includes a pawl portion that engages with the gear and a lever portion extending from the pawl portion, the pawl portion may be made of the second structure and the lever portion may be made of the first structure.

[0007] Furthermore, the method for manufacturing an electroformed component in which a first structure and a second structure are connected comprises: a groove forming step of forming a groove on the surface of a substrate that includes a region corresponding to the planar shape of the first structure, leaving at least island portions corresponding to the planar shape of the second structure; a conductive film forming step of forming a conductive film on the surface of the substrate including the inside of the groove; a photoresist forming step of forming a photoresist layer on the conductive film; a mask forming step of patterning the photoresist layer and opening a region corresponding to the planar shape of the first structure; an electroforming step of depositing an electroformed member on the conductive film in the opening of the photoresist layer by electroforming with the conductive film as one electrode; and a grinding and polishing step of grinding and polishing the substrate from the side opposite to the side on which the electroformed member was formed, up to at least the bottom of the groove, to remove it. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a method for manufacturing a component in which two or more members are integrally formed, which is compact and capable of connecting each member with high precision and stability. [Brief explanation of the drawing]

[0009] [Figure 1] These figures illustrate an electroformed component (feed claw) in an embodiment of the present invention, where (a) is a plan view of the feed claw and (b) is a front view of the feed claw. [Figure 2] This embodiment shows the groove formation process in the manufacturing method of the electroformed component (feed claw), where (a) is a plan view of the substrate and (b) is a cross-sectional view AA of (a). [Figure 3] This embodiment shows the conductive film formation process in the manufacturing method of the electroformed component (feed claw), where (a) is a plan view of the substrate and (b) is a cross-sectional view AA of (a). [Figure 4] This example shows the mask formation process in the manufacturing method of the electroformed component (feed claw), where (a) is a plan view of the substrate and (b) is a cross-sectional view AA of (a). [Figure 5] This is a cross-sectional view showing the electroforming process in the manufacturing method of the electroformed component (feed claw) of this embodiment. [Figure 6] This is a cross-sectional view showing the photoresist removal step in the manufacturing method of the electroformed component (feed claw) of this embodiment. [Figure 7] This is a cross-sectional view showing the grinding and polishing process in the manufacturing method of the electroformed component (feed claw) of this embodiment. [Modes for carrying out the invention]

[0010] The following describes the electroformed component and its manufacturing method according to the present invention, using the feed pawl of a watch component and its manufacturing method as examples. Figure 1 is a diagram illustrating the electroformed component (feed pawl) in an embodiment of the present invention, where (a) is a plan view of the feed pawl and (b) is a front view of the feed pawl. The feed pawl 10 in this embodiment is a rod-shaped component with a substantially rectangular cross-section and comprises a lever portion 11 as the first structure of the present invention and a substantially rectangular hard portion 12 as the second structure of the present invention, which is connected to one side of one end of the lever portion 11. The feed pawl 10 performs a gear feeding operation by transmitting the force received at the other end of the lever portion 11 to the gear via the hard portion 12, which is in contact with the gear located at one end of the lever portion 11.

[0011] The lever portion 11 is made of nickel (Ni) and formed by electroforming. The lever portion 11 may be made of any material that can be formed by electroforming, and may be made of metallic materials such as copper (Cu), gold (Au), or silver (Ag). The portion of the lever portion 11 that connects to the hard portion 12 on one side surface has a recessed portion 11a. The recessed portion 11a consists of wedge-shaped recesses and protrusions that alternately continue in the direction in which the lever portion extends, and is arranged over a predetermined length from the end of the lever portion 11 on one side surface of the lever portion 11. The recessed portion 11a is formed on the lever portion 11 in such a way that the recesses and protrusions can be seen when the connection interface between the lever portion 11 and the hard portion 12 is viewed from above, or in other words, when the side surface of the lever portion 11 to which the hard portion 12 is connected is observed from a viewpoint parallel to that surface. The side surface of the lever portion 11 is also provided with a metal film 13 on its outer circumference. The metal film 13 is formed, for example, as a laminated film of titanium (Ti) and nickel (Ni).

[0012] The hard portion 12 is made of silicon (Si), which has excellent processability by etching and is harder than the lever portion 11 (a material with higher hardness). The portion of the hard portion 12 that connects to the lever portion 11 has a recessed portion 12a that engages with the recessed portion 11a of the lever portion 11. The lever portion 11 and the hard portion 12 are arranged so that the recessed portions 11a and 12a formed on each of them engage with each other, and are connected via a metal film 13. Here, the hard portion 12 is connected only on the side surface of the lever portion 11 which is formed by electroforming, along the deposition direction.

[0013] In the electroformed component of the present invention, exemplified by the feed claw 10, two or more different members are integrally formed using electroforming, enabling high precision and stable connection while ensuring the adhesion strength of each member. Furthermore, by connecting one member only to the side surface of the other member formed by electroforming along the deposition direction, the component can be miniaturized compared to a configuration in which a structure is provided on the surface or back side that connects to the side surface of the member.

[0014] Furthermore, by making the connection parts of each component interlocking protrusions and recesses, a more stable connection with higher adhesion strength becomes possible. In this embodiment, when the feed pawl 10 performs a feeding operation against the gear, the hard part 12 becomes the contact part with the gear, and by setting the sides forming the recesses and protrusions of the protrusions and recesses

[0015] Furthermore, a protective film (not shown) covering the connection interface between the lever portion 11 and the rigid portion 12 may be provided on one or both of the front and back surfaces of the lever portion 11 and the rigid portion 12. The protective film can be formed of, for example, a metal film such as nickel (Ni). By providing the protective film, the connection between the lever portion 11 and the rigid portion 12 can be made stronger.

[0016] Next, a method for manufacturing an electroformed part (feed claw) according to an embodiment of the present invention will be described. The feed claw 10 of this embodiment is manufactured by the following steps. [Groove formation step: FIG. 2] FIG. 2 shows the groove formation step in the method for manufacturing an electroformed part (feed claw) of this embodiment, (a) is a plan view of the substrate, and (b) is a cross-sectional view taken along line A-A of (a). Note that FIG. 2 shows a method for simultaneously manufacturing three feed claws 10. First, a silicon (Si) substrate 110, which is a constituent material of the lever portion 10, is prepared. Then, a region corresponding to the planar shape of the rigid portion 12 is left as an island portion 112 on the surface of the substrate 110, and a groove 111 is formed so as to include at least a region corresponding to the planar shape of the lever portion 11. In this embodiment, the groove 111 is formed in all regions of the substrate 110 except for the island portion 112 corresponding to the planar shape of the rigid portion 12. The formation of the groove 111 is performed by forming a pattern of the island portion 112 with a photoresist on the substrate 110 and etching the substrate 110 using this photoresist pattern as a mask.

[0017] [Conductive film formation step: FIG. 3] FIG. 3 shows the conductive film formation step in the method for manufacturing an electroformed part (feed claw) of this embodiment, (a) is a plan view of the substrate, and (b) is a cross-sectional view taken along line A-A of (a). After the groove formation step, a conductive film 113 is formed on the surface of the substrate 110 in which the groove 111 is formed. The conductive film 113 is formed so as to cover the entire surfaces of the groove 111 and the island portion 112. The conductive film 113 is formed of, for example, a laminated film of titanium (Ti) and nickel (Ni) (titanium is on the side of the substrate 110), but the conductive film 113 is not limited to this material and may be any material having conductivity. When the substrate 110 has conductivity, the conductive film 113 may not be provided.

[0018] [Mask formation process: Figure 4] Figure 4 shows the mask formation process in the method for manufacturing the electroformed part (feed claw) of this embodiment. (a) is a plan view of the substrate, and (b) is a cross-sectional view taken along line A-A of (a). After the conductive film formation process, a photoresist layer 114 is formed on the conductive film 113. The photoresist layer 114 may be either a positive resist or a negative resist. In this embodiment, the explanation is based on the premise that the photoresist layer 114 is a negative resist. Next, a photomask (not shown) is placed on the surface (upper surface shown in the figure) side of the photoresist layer 114, and ultraviolet light is irradiated onto the photoresist layer 114 through the photomask from above. Then, after irradiating with ultraviolet light, the photoresist layer 114 is developed.

[0019] The photomask has a pattern composed of a light-transmitting portion that allows ultraviolet light to pass through and a light-blocking portion that does not allow ultraviolet light to pass through, and this pattern is formed corresponding to the planar shape of the lever portion 11. When ultraviolet light is irradiated through the photomask, in the photoresist layer 114, the portion below the light-transmitting portion becomes insoluble due to passing through the ultraviolet light and being irradiated with ultraviolet light L, and remains even after the development process. On the other hand, in the photoresist layer 114, the portion below the light-blocking portion becomes soluble because it blocks the ultraviolet light and is not irradiated with ultraviolet light, and is removed by the development process. In the case where the photoresist layer 114 is a positive resist, on the contrary, the light-blocking portion forms an insoluble portion in the photoresist layer 114, and the light-transmitting portion forms a soluble portion in the photoresist layer 114.

[0020] As shown in Figure 4, when the soluble portion of the photoresist layer 114 is removed by the development process, the portion where the soluble portion existed is opened, and the conductive film 113 is exposed.

[0021] [Electroforming process: Figure 5] Figure 5 is a cross-sectional view showing the electroforming process in the manufacturing method of the electroformed component (feed claw) of this embodiment, and shows the AA cross-section shown in Figure 4 during the electroforming process. After the mask formation process, the substrate 110 and the nickel anode are immersed in a plating solution containing nickel ions, and current is passed through the conductive film 113 of the substrate 110 as the cathode and the nickel anode as the anode, causing nickel (Ni) to deposit and grow (deposit) on the conductive film 113 exposed from the photoresist layer 114. Through this process, a nickel (Ni) structure (electroformed product) 115 is formed within the opening of the photoresist layer 114.

[0022] [Photoresist removal process: Figure 6] Figure 6 is a cross-sectional view showing the photoresist removal process in the manufacturing method of the electroformed component (feed claw) of this embodiment, and shows the AA cross-section shown in Figure 4 during the photoresist removal process. After the electroformed product 115 is formed on the substrate 110, the photoresist layer 114 is removed from the substrate 110 using a resist stripping solution. The removal of the photoresist layer 114 may also be performed by a dry process using a gas such as plasma or ozone.

[0023] [Grinding and polishing process: Figure 7] Figure 7 is a cross-sectional view showing the grinding and polishing process in the manufacturing method of the electroformed component (feed claw) of this embodiment, and shows the AA cross-section shown in Figure 4 during the grinding and polishing process. After the electroforming process, the electroformed product 115 formed in the electroforming process is ground and polished until its upper surface is flat. In this embodiment, the electroformed product 115 was ground and polished until its entire upper surface was flat and the island portion 112 covered with the conductive film 113 was exposed. This grinding and polishing may be performed before the photoresist removal process. In that case, the photoresist layer 114 may be ground and polished together with the electroformed product 115, etc.

[0024] Next, the substrate 110 is ground and polished from the bottom side where the electroformed product 115 is not formed. This grinding and polishing is continued until the electroformed product 115 is exposed from the bottom side. Through this process, an electroformed component (feed claw 10) can be manufactured in which the island portion 112 (hard portion 12) and the electroformed product 115 (lever portion 11) are connected by a conductive film 113 (metal film 13).

[0025] Furthermore, if a protective film (not shown) covering the connection interface between the lever portion 11 and the hard portion 12 is to be provided on either the front or back surface of the lever portion 11 or both surfaces of the hard portion 12, it can be formed by vapor deposition, sputtering, etc., after the grinding and polishing process and before the parts removal process. By forming a protective film on multiple feed claws 10 connected by the photoresist layer 114 at once, and then performing the parts removal process, the protective film can be formed efficiently. The protective film formed on the photoresist layer 114 is removed simultaneously with the removal of the photoresist layer 114 during the parts removal process.

[0026] Although the electroformed component and its manufacturing method of the present invention have been described above based on examples, the present invention is not limited to these examples, and various other embodiments are possible. [Explanation of Symbols]

[0027] 10 Feed claws 11 Lever section 11a Uneven part 12 Hard part 12a Uneven part 13 Metal film 110 circuit boards 111 Groove 112 Islands 113 Conductive film 114 Photoresist layer 115 Electroformed products

Claims

1. An electroformed component comprising a first structure formed by depositing electroformed material and a second structure connected to the first structure, wherein the second structure is connected only to the side surface of the first structure along the depositing direction.

2. The electroformed component according to claim 1, characterized in that the side surface of the second structure connected to the first structure and the side surface of the first structure connected to the second structure each have an uneven portion, and when the connection interface between the first structure and the second structure is viewed from above, the uneven portions are engaged with each other.

3. The electroformed component according to claim 1, characterized in that a metal film covering the connection interface between the first structure and the second structure is provided on the first structure and the second structure.

4. The electroformed part according to any one of claims 1 to 3, characterized in that the electroformed product is a clock component.

5. The electroformed component is a feed pawl for engaging with a gear to rotate the gear, and the feed pawl includes a pawl portion that engages with the gear and a lever portion extending from the pawl portion, wherein the pawl portion is made of the second structure and the lever portion is made of the first structure, as described in claim 4.

6. In a method for manufacturing an electroformed component in which a first structure and a second structure are connected, A groove forming step is to form grooves on the surface of the substrate, leaving island portions corresponding to at least the planar shape of the second structure and including regions corresponding to the planar shape of the first structure, A conductive film forming step of forming a conductive film on the surface of the substrate including the groove, A photoresist formation step of forming a photoresist layer on the conductive film, A mask formation step involves patterning the photoresist layer and opening up a region corresponding to the planar shape of the first structure. An electroforming step in which an electroformed member is deposited on the conductive film within the opening of the photoresist layer by electroforming with the conductive film as one electrode, A grinding and polishing step in which the substrate is ground and polished to remove the electroformed member from the surface opposite to the surface on which the electroformed member is formed, up to at least the bottom surface of the groove, A method for manufacturing electroformed components, characterized by having the following features.

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