1. Field of the Invention
The present invention relates to a mold of a minute component and a method for manufacturing the same, and a method for manufacturing a minute component; in particular, to a mold of an electroformed component having a multistage structure and a method for manufacturing the same, and a method for manufacturing an electroformed component.
2. Description of the Related Art
Conventional multistage electroforming molds include a concave portion constituted of a basal part formed of a substrate and side walls formed by a resist agent on the upper face of the substrate, wherein a multistage configuration was obtained by forming a second layer mold on a component of a first layer having been formed in the concave portion by an electroforming method. In conventional electroforming molds and methods for manufacturing an electroformed component, therefore, it was necessary to form layers of a mold and a component layer by layer in accordance with number of steps included in a component.
However, according to the electroforming mold and the method for manufacturing the same mentioned above, it was required to manufacture a component and an electroforming mold layer by layer in accordance with number of steps included in a component.
Further, since height control of the layer of a component precipitated by electroforming is difficult, the surface does not become even. Since a mold and a component of the following layer are formed on the upper face of the layer of the component having an uneven surface and a step portion, there is difficulty in forming the mold and the component of the following layer as well as in height control. Controlling the thickness of the electroforming mold step by step is possible through a grinding process, but ground residues through the grinding remain on the electroforming mold and the resist, thereby making height control in post-processes difficult. Further, when electroforming is carried out in a state of being divided into multiple cycles, there also occurs such problems that adhesive power between the interface of respective layers weakens to decrease strength of an electroformed object, and that, caused by different stresses of the electroformed objects formed in respective electroforming processes, configuration of the electroformed object changes.
The invention is going to solve such problems that exist in a conventional electroforming mold and a method for manufacturing an electroformed component, and aims to manufacture an electroforming mold capable of height control as well as to manufacture an intended component in one electroforming process.
The method for manufacturing an electroforming mold according to the invention includes the steps of forming a first negative type photosensitive material on the upper face of an electroconductive substrate, exposing the first negative type photosensitive material through a photomask pattern arranged above the first negative type photosensitive material, forming a positive type photosensitive material on the upper face of the first negative type photosensitive material, exposing the positive type photosensitive material through a photomask pattern arranged above the positive type photosensitive material, developing the positive type photosensitive material to remove the exposed region of the positive type photosensitive material, forming a film of an electroconductive layer on the upper faces of the first negative type photosensitive material exposed by removing the exposed region of the positive type photosensitive material and the positive type photosensitive material, removing the positive type photosensitive material and the electroconductive layer formed on the upper face of the positive type photosensitive material, forming a second negative type photosensitive material on the upper face of the first negative type photosensitive material exposed by removing the electroconductive layer and the positive type photosensitive material and on the upper face of the electroconductive layer, exposing the second negative type photosensitive material through a photomask pattern arranged above the second negative type photosensitive material, and developing the first negative type photosensitive material and the second negative type photosensitive material to remove the unexposed region of the first negative type photosensitive material and the unexposed region of the second negative type photosensitive material.
Further, the method for manufacturing an electroforming mold according to the invention includes the steps of forming a film of a first electroconductive layer on the upper face of a substrate, forming a first negative type photosensitive material on the upper face of the first electroconductive layer, exposing the first negative type photosensitive material through a photomask pattern arranged above the first negative type photosensitive material, forming a positive type photosensitive material on the upper face of the first negative type photosensitive material, exposing the positive type photosensitive material through a photomask pattern arranged above the positive type photosensitive material, developing the positive type photosensitive material to remove the exposed region of the positive type photosensitive material, forming a film of a second electroconductive layer on the upper faces of the first negative type photosensitive material exposed by removing the exposed region of the positive type photosensitive material and the positive type photosensitive material, removing the positive type photosensitive material and the second electroconductive layer formed on the upper face of the positive type photosensitive material, forming a second negative type photosensitive material on the upper face of the first negative type photosensitive material exposed by removing the second electroconductive layer and the positive type photosensitive material and on the upper face of the second electroconductive layer, exposing the second negative type photosensitive material through a photomask pattern arranged above the upside of the second negative type photosensitive material, and developing the first negative type photosensitive material and the second negative type photosensitive material to remove the unexposed region of the first negative type photosensitive material and the unexposed region of the second negative type photosensitive material.
Further, the method for manufacturing an electroforming mold according to the invention includes the steps of forming a first positive type photosensitive material on the upper face of an electroconductive substrate, exposing the first positive type photosensitive material through a photomask pattern arranged above the first positive type photosensitive material, forming a negative type photosensitive material on the upper face of the first positive type photosensitive material, exposing the negative type photosensitive material through a photomask pattern arranged above the negative type photosensitive material, developing the negative type photosensitive material to remove the unexposed region of the negative type photosensitive material, forming a film of an electroconductive layer on the upper faces of the first positive type photosensitive material exposed by removing the exposed region of the negative type photosensitive material and the negative type photosensitive material, removing the negative type photosensitive material and the electroconductive layer formed on the upper face of the negative type photosensitive material, forming a second positive type photosensitive material on the upper face of the first positive type photosensitive material exposed by removing the negative type photosensitive material and on the upper face of the electroconductive layer, exposing the second positive type photosensitive material through a photomask pattern arranged above the second positive type photosensitive material, and developing the first positive type photosensitive material and the second positive type photosensitive material to remove the exposed region of the first positive type photosensitive material and the exposed region of the second positive type photosensitive material.
Further, the method for manufacturing an electroforming mold according to the invention includes the steps of forming a positive type photosensitive material on the upper face of an electroconductive substrate, exposing the positive type photosensitive material through a photomask pattern arranged above the positive type photosensitive material, forming a first negative type photosensitive material on the upper face of the positive type photosensitive material, exposing the first negative type photosensitive material through a photomask pattern arranged above the first negative type photosensitive material, developing the first negative type photosensitive material to remove the unexposed region of the first negative type photosensitive material, forming a film of an electroconductive layer on the upper faces of the positive type photosensitive material exposed by removing the exposed region of the first negative type photosensitive material and the first negative type photosensitive material, removing the first negative type photosensitive material and the electroconductive layer formed on the upper face of the first negative type photosensitive material, forming a second negative type photosensitive material on the upper side of the positive type photosensitive material exposed by removing the electroconductive layer and the first negative type photosensitive material and on the upper face of the electroconductive layer, exposing the second negative type photosensitive material through a photomask pattern arranged above the second negative type photosensitive material, and developing the positive type photosensitive material and the second negative type photosensitive material to remove the exposed region of the positive type photosensitive material and the unexposed region of the second negative type photosensitive material.
Further, the method for manufacturing an electroforming mold according to the invention includes the steps of forming a first negative type photosensitive material on the upper face of an electroconductive substrate, forming a positive type photosensitive material on the upper face of the first negative type photosensitive material, exposing the positive type photosensitive material through a mask pattern arranged above the positive type photosensitive material, developing the positive type photosensitive material to remove the exposed region of the positive type photosensitive material, forming a film of an electroconductive layer on the upper faces of the first negative type photosensitive material exposed by removing the exposed region of the positive type photosensitive material and the positive type photosensitive material, removing the positive type photosensitive material and the electroconductive layer formed on the upper face of the positive type photosensitive material, forming a second negative type photosensitive material on the upper face of the first negative type photosensitive material exposed by removing the electroconductive layer and the positive type photosensitive material and on the upper face of the electroconductive layer, exposing the second negative type photosensitive material through a mask pattern arranged above the second negative type photosensitive material, and developing the first negative type photosensitive material and the second negative type photosensitive material to remove the unexposed region of the first negative type photosensitive material and the unexposed region of the second negative type photosensitive material.
Further, the method for manufacturing an electroforming mold according to the invention includes the steps of forming a layer of a first electroconductive layer on the upper face of a substrate, forming a first negative type photosensitive material on the upper face of the first electroconductive layer, forming a positive type photosensitive material on the upper face of the first negative type photosensitive material, exposing the positive type photosensitive material through a mask pattern arranged above the positive type photosensitive material, developing the positive type photosensitive material to remove the exposed region of the positive type photosensitive material, forming a film of a second electroconductive layer on the upper faces of the first negative type photosensitive material exposed by removing the exposed region of the positive type photosensitive material and the positive type photosensitive material, removing the positive type photosensitive material and the second electroconductive layer formed on the upper face of the positive type photosensitive material, forming a second negative type photosensitive material on the upper face of the first negative type photosensitive material exposed by removing the second electroconductive layer and the positive type photosensitive material and on the upper face of the second electroconductive layer, exposing the second negative type photosensitive material through a mask pattern arranged above the second negative type photosensitive material, and developing the first negative type photosensitive material and the second negative type photosensitive material to remove the unexposed region of the first negative type photosensitive material and the unexposed region of the second negative type photosensitive material.
The electroforming mold according to the invention includes an electroconductive substrate, a first negative type photosensitive material that is formed on the upper face of the electroconductive substrate and has a first through-hole in the thickness direction, an electroconductive layer formed on a part of the face of the first negative type photosensitive material opposite the face being in contact with the electroconductive substrate, and a second negative type photosensitive material that is formed on a part of the face of the electroconductive layer opposite the face being in contact with the first negative type photosensitive material and has a second through-hole above the face including the aperture face of the first through-hole with respect to the upper face of the first negative type photosensitive material.
Further, the electroforming mold of the invention includes a first electroconductive layer formed on a substrate, a first negative type photosensitive material that is formed on the face of the first electroconductive layer opposite the face being in contact with the substrate and has a first through-hole in the thickness direction, a second electroconductive layer formed on a part of the face of the first negative type photosensitive material opposite the face being in contact with the first electroconductive layer, and a second negative type photosensitive material formed on a part of the face of the second electroconductive layer opposite the face being in contact with the first negative type photosensitive material and has a second through-hole above the face including the aperture face of the first through-hole with respect to the upper face of the first negative type photosensitive material.
Further, the electroforming mold according to the invention includes an electroconductive substrate, a first negative type photosensitive material that is formed on the upper face of the electroconductive substrate and has a first through-hole in the thickness direction, a second negative type photosensitive material that is formed on a part of the upper face of the first negative type photosensitive material and has a second through-hole passing through in the thickness direction on the upside of the first through-hole, and an electroconductive layer formed within the second through-hole and on the upper face of the first negative type photosensitive material.
Further, the electroforming mold according to the invention includes a substrate, a first electroconductive layer formed on the upper face of the substrate, a first negative type photosensitive material that is formed on the upper face of the first electroconductive layer and has a through-hole in the thickness direction, a second negative type photosensitive material that is formed on a part of the upper face of the first negative type photosensitive material and has a second through-hole passing through in the thickness direction above the first through-hole, and a second electroconductive layer formed within the second through-hole and on the upper face of the first negative type photosensitive material.
The method for manufacturing an electroformed component according to the invention includes the steps of dipping an electroforming mold in an electroforming liquid, the electroforming mold having an electroconductive substrate, a first negative type photosensitive material that is formed on the upper face of the electroconductive substrate and has a first through-hole in the thickness direction, an electroconductive layer formed on a part of the face of the first negative type photosensitive material opposite the face being in contact with the electroconductive substrate, a second negative type photosensitive material that is formed on a part of the face of the electroconductive layer opposite the face being in contact with the first negative type photosensitive material and has a second through-hole above the face including an aperture face of the first through-hole with respect to the upper face of the first negative type photosensitive material, applying voltage to the electroconductive substrate, precipitating a metal on the exposed face of the electroconductive substrate, bringing a part of the precipitated metal into contact with the electroconductive layer to apply voltage to the electroconductive layer, and precipitating a metal on the exposed face of the precipitated metal and the exposed face of the electroconductive layer.
Further, the method for manufacturing an electroformed component according to the invention includes the steps of dipping an electroforming mold in an electroforming liquid, the electroforming mold having a first electroconductive layer formed on a substrate, a first negative type photosensitive material that is formed on the face of the first electroconductive layer opposite the face being in contact with the substrate and has a first through-hole in the thickness direction, a second electroconductive layer formed on a part of the face of the first negative type photosensitive material opposite the face being in contact with the first electroconductive layer, a second negative type photosensitive material that is formed on a part of the face of the second electroconductive layer opposite the face being in contact with the first negative type photosensitive material and has a second through-hole above the face including an aperture face of the first through-hole with respect to the upper face of the first negative type photosensitive material, applying voltage to the first electroconductive layer, precipitating a metal on the exposed face of the first electroconductive layer, bringing a part of the precipitated metal into contact with the second electroconductive layer to apply a voltage to the second electroconductive layer, and precipitating a metal on the exposed face of the precipitated metal and the exposed face of the second electroconductive layer.
In the electroforming mold and the method for manufacturing the same according to the invention, upon manufacturing a multistage electroformed component, without forming a mold for forming a following layer on the layer of the formed component through removing a resist forming the side wall of an electroforming mold every time when one layer is formed, negative resists are formed and exposed, and, after superimposing negative resists of respective stages into a laminated layer, development is carried out, thereby manufacturing a multistage electroforming mold having an electroconductive layer on a basal part of respective step portions. Accordingly, it becomes unnecessary to carry out electroforming every time when respective stages are formed, and an intended component can be formed in one electroforming process.
Further, since a mold is manufactured without forming a resist for a following layer on the layer of a component under a forming process, it is possible to manufacture a mold capable of height control as well as to prevent the interface of layers between the electroformed parts from becoming uneven or height thereof from becoming uneven.
Further, when an electroconductive layer is formed on the surface of a resist in a lower layer so that the lower resist layer has a region being in contact with an upper resist layer, since the degree of adhesion increases in the region where the resists having affinity are in contact with each other, strong connection can be achieved. Thus, a mold with a high strength can be obtained as an electroforming mold.
Furthermore, when a mold is formed so that it has plural concave portions on one substrate and that each of electroconductive layers arranged on the respective concave portions is arranged so as to be separated from electroconductive layers arranged for other concave portions, since each of concave portions precipitates an electroformed object independently, a uniform electroformed component can be obtained.
Hereinafter, embodiments of the invention will be described based on
First, in
Thickness of the substrate 1 is around from 100 μm to 10 mm. A thickness that can keep strength of the electroforming mold 101 in an electroforming process, grinding process and the like described later may be sufficient. Thickness of an electroconductive layer 2 is around from 5 nm to 10 μm. A thickness that makes conduction possible in an electroforming process described later may be sufficient. Thickness of a photoresist 3 is form 1 μm to 5 mm, which is approximately the same thickness as that of the first step of an electroformed object to be produced. As for material of the substrate 11, a material generally used in the silicon process such as glass and silicon, or a metal material such as stainless steel and aluminum is used. Material of the electroconductive layer 2 is gold (Au), silver (Ag), nickel (Ni) or the like, and chromium (Cr), titanium (Ti) or the like may be formed between the electroconductive layer 2 and the substrate 1 as an anchor metal (not shown) for strengthening adhesion force of the electroconductive layer 2. In this connection, when the material of the substrate 1 is a metal, the electroconductive layer 2 is not necessarily required. As the photoresist 3, a negative type photoresist is used.
Further, the photoresist 3 may also be a chemical amplification type photoresist. When producing a structure with a high aspect ratio, for the photoresist 3, use of an epoxy-type resin-based chemical amplification type photoresist is desirable. Further, as for the photoresist 3, a photoresist, which is insoluble in a developer of a light-absorbing body 10 in a developing process of the light-absorbing body 10 described later, is used. A formation method of the electroconductive layer 2 is a sputtering method, vacuum evaporation method, or the like. A formation method of the photoresist 3 is spin coating, dip coating or spray coating, or a photoresist film in sheet may be stuck to the substrate 1. Further, plural photoresist films in sheet may be laminated to give a photoresist 3 having an intended thickness. In order to form the insoluble portion 3a and the soluble portion 3b, ultraviolet light is exposed through a photo mask. Further, when the photoresist 3 is of a chemical amplification type, PEB (Post Exposure Bake) is carried out after the exposure.
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In other word, the photo mask 4b, which is larger than the photo mask 4a arranged above the photoresist 3, is arranged above the face of the light-absorbing body 10 opposite to the face being in contact with the unexposed region of the photoresist 3. More specifically, the photomask 4b is arranged so as to cover the upside of the face opposite the face being in contact with the boundary between the unexposed region and the exposed region of the photoresist 3, with respect to the light-absorbing body 10. On this occasion, the photoresist 3 is arranged so that it covers the upside of the face opposite a face being in contact with the upper face of the photoresist 3 lying between from 1 μm to 500 μm from the boundary between the unexposed region and the exposed region in the direction toward the exposed region.
Then, after arranging the photo mask 4b, light is irradiated from above the photo mask 4b, and ultraviolet light 20b is irradiated through the photo mask 4b to the light-absorbing body 10. At this time, the soluble portion 3b is not irradiated by the ultraviolet 20b, because the upside of the portion is covered with the photo mask 4b.
In this connection, the thickness of the light-absorbing body 10 is sufficient when it is thicker than that of an electrode in an electrode-forming process described later, and is 20 μm or less. As for the light-absorbing body 10, a positive type photoresist is used, and a positive type resist of novolac-type resin is used. The formation method of the light-absorbing body 10 is spin coating or spray coating.
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In this connection, in the case where the electroconductive layer 5 is formed by using a spattering method without forming a light-absorbing body 10, since the process uses plasma, the soluble portion 3b is also irradiated by ultraviolet light to make the soluble portion 3b insoluble in a development process described later. However, in the invention, since the light-absorbing body 10 is formed on the soluble portion 3b, the ultraviolet light is absorbed by the light-absorbing body 10 upon forming the electroconductive layer 5 by a spattering method and the ultraviolet light is not irradiated to the soluble portion 3b. Further, since the light-absorbing body 10 is constituted of a positive type photoresist, it has such nature that it becomes easily soluble when irradiated by ultraviolet light. Accordingly, in a liftoff process described later, the light-absorbing body 10 can be removed easily.
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Then, after arranging the photomask 4c, ultraviolet light 20a is irradiated to carry out exposure, followed by developing to form an insoluble portion 6a and a soluble portion 6b.
Thickness of the photoresist 6 is around from 1 μm to 5 mm, and is approximately equal to that of a second step of an electroformed object to be formed. As for the photoresist 6, a negative type photoresist is used. Further, the photoresist 6 may be a chemical amplification type photoresist. When producing a structure with a high aspect ratio, as a photoresist 6, desirably an epoxy-type resin-based chemical amplification type photoresist is used. In this connection, the material of the photoresist 6 is desirably the same as that of the photoresist 3, because they can be developed with the same developer in a development process described later, but a material different from that of the photoresist 3 may be used. A formation method of the photoresist 6 is spin coating, dip coating or spray coating, or a photoresist film in sheet may be stuck onto the electroconductive laser 5. Further, plural photoresist films in sheet may be laminated to give a photoresist 6 having an intended thickness. In order to form an insoluble portion 6a and a soluble portion 6b, ultraviolet light 20a is exposed through the photo mask 4c. Further, when the photoresist 6 is of a chemical amplification type, PEB (Post Exposure Bake) is carried out after the exposure.
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According to the above-described process, the electroforming mold 101, which includes the first electroconductive layer 2 formed on the substrate 1, the first negative type photosensitive material 3 that is formed on the face of the first electroconductive layer 2 opposite the face being in contact with the substrate 1 and has the through-hole 24 in the thickness direction, the second electroconductive layer 5 formed on a part of the face of the first negative type photosensitive material 3 opposite the face being in contact with the first electroconductive layer 2, and the second negative type photosensitive material 6 that is formed on a part of the face of the second electroconductive layer 5 opposite the face being in contact with the first negative type photosensitive material 3 and has the second through-hole 25 above the face including the aperture face of the first through-hole 24 with respect to the upper face of the first negative type photosensitive material 3, is obtained.
The second through-hole 25 is formed above the face including the edge portion of the aperture face of the first through-hole 24 with respect to the upper face of the photoresist 3 so that the second through-hole 25 overlies and completely exposes both the first through-hole 24 and a peripheral part of the elecroconductive layer 5 that surrounds the first through-hole 25. That is, they are in such positional relation that, when the second through-hole 25 is viewed from above, the first through-hole 24 is positioned within and completely exposed by the second through-hole 25. Further, since the arrangement is so that, when the photo mask 4b is arranged, the mask 4b covers the upside of the soluble portion 3b as well as catches on a part of the insoluble portion 3a, the electroconductive layer 5 is formed so as to have an edge portion formed apart from the face forming the first through-hole 24, i.e., the electroconductive layer 5 is spaced from the edge of the first through-hole 24. That is, as shown in
As for combination of the photosensitive materials, as mentioned above, it is preferred that the photoresist 3 and the photoresist 6 are negative type photoresists and the light-absorbing body 10 is a positive type photoresist. Because, the region of the soluble portion 3b is not exposed in the exposure of the light-absorbing body 10 in
In addition to the above-described combination of photosensitive materials, replacement of a negative type photoresist with a positive type photoresist with regard to the photoresist 3 and the photoresist 6 and replacement of a positive type photoresist with a negative type photoresist with regard to the light-absorbing body 10 also makes the operation possible.
Further, replacement of a negative type photoresist with a positive type photoresist with regard to the photoresist 3 and replacement of a positive type photoresist with a negative type photoresist with regard to the light-absorbing body 10 also makes the operation possible.
An electroforming tank 21 is filled with an electroforming liquid 22, and the electroforming mold 101 and an electrode 23 are dipped in the electroforming liquid 22. The electroforming liquid 22 varies depending on a metal to be precipitated and, for example, an aqueous solution containing nickel sulfamate hydrated salt is used when nickel is intended to be precipitated. Material of the electrode 23 is substantially the same material as a metal to be precipitated, thus nickel is employed when nickel is intended to be precipitated, and a nickel plate or a titanium basket containing nickel balls is used as the electrode 23.
In this connection, in the manufacturing method of the invention, a material to be precipitated is not limited to nickel. The method can be applied to all the materials capable of electroforming, such as cupper (Cu), cobalt (Co) and tin (Sn). The electroconductive layer 2 of the electroforming mold 101 is connected to a power source V. By supply of electrons through the electroconductive layer 2 by the voltage of the power source V, a metal is precipitated gradually from the electroconductive layer 2. The precipitated metal grows in the thickness direction of the substrate 1.
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As the result of the above-described process, the electroforming mold 102 that is the same as the electroforming mold 101 obtained in the first embodiment and has a through-pattern 7a formed in the through-holes 24 and 25 can be obtained. When an electroformed component is formed by using the electroforming mold 102, a hollow portion coaxial for respective stages is formed at the center.
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Further, so as not to expose the light-absorbing body 10 formed in a region for forming an insoluble portion 6a of a photoresist 6 in a process described later with respect to the photoresist 3, a photo mask (second mask pattern) 4bb is arranged above the light-absorbing body 10. On this occasion, the photo mask 4bb is arranged in a position separated from the photo mask 4ba so that it covers a region for forming an insoluble portion 6a described later and catches on a region for not forming the insoluble portion 6a. In this connection, the photo mask 4ba may be arranged so that it covers the region to be the insoluble portion 6a alone, or may be arranged so that it not completely covers the region to be the insoluble portion 6a.
Next, ultraviolet light 20b is irradiated from above the photo masks 4ba and 4bb to irradiate the ultraviolet light 20b to the light-absorbing body 10 through the photo masks 4ba and 4bb. At this time, the upside of the soluble portion 3b is covered with the photo mask 4ba, therefore the portion 3b is not irradiated by the ultraviolet light 20b and is not exposed.
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In this connection, when the photo mask 4ba is arranged so as to cover the region of the soluble portion 3b alone, the light-absorbing body 10a is formed on the upper face of the soluble portion 3b, and, when it is arranged so as to cover the soluble portion 3b not completely, the light-absorbing body 10a is formed in such away that it covers up to the inner periphery of the boundary between the soluble portion 3b and the insoluble portion 3a.
On the other hand, the light-absorbing body 10b is formed in a region where the insoluble portion 6a of the photoresist 6 is formed in a process described later. Since the photo mask 4bb is arranged so that it covers the region for forming the insoluble portion 6a and catches on the region for not forming the insoluble portion 6a, the light-absorbing body 10b is formed so as to cover the face where the insoluble portion 6a is to be formed later and also to catch on a part of the face where the insoluble portion 6a is not to be formed.
In this connection, when the photo-mask 4bb is arranged so as to cover the region for forming the insoluble portion 6a alone, the light-absorbing body 10b is formed on the upper face of the face for forming the insoluble portion 6a, and, when the photo mask 4bb is arranged so as to cover the region for forming the insoluble portion 6a not completely, the light-absorbing body 10b is formed in such a way that it covers up to the portion slightly recessed from the boundary between the faces forming and not forming the insoluble portion 6a into the face side for forming the insoluble portion 6a.
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Then, the ultraviolet light 20a is irradiated from above the photo mask 4c and, through the photo mask 4c, the ultraviolet light 20a is irradiated to the photoresist 6, thereby forming the insoluble portion 6a that is the exposed region and the soluble portion 6b that is an unexposed region.
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As the result of the above-described process, the electroforming mold 103, which includes the substrate 1, the first electroconductive layer 2 formed on the upper face of the substrate 1, the first negative type photosensitive material 3 that is formed on the upper face of the first electroconductive layer 2 and has the first through-hole 24 in the thickness direction, the second negative type photosensitive material 6 that is formed on a part of the upper face of the first negative type photosensitive material 3 and has the second through-hole 25 passing through in the thickness direction above the first through-hole 24, and the second electroconductive layer 5 that is formed within the second through-hole 25 and on the upper face of the first negative type photosensitive material 3 wherein the second electroconductive layer 5 is formed while being separated relative to the second negative type photosensitive material 6 by a predetermined distance W6, is obtained. One end (lower end) of the first through-hole 24 exposes the first electroconductive layer 2 and the side of the through-hole 25 exposes the first negative type photosensitive material 3.
Here,
As described above, when the electrode 5a is formed on the upper face of the insoluble portion 3a in a state of being separated from the insoluble portion 6a so as not to be brought into contact with the insoluble portion 6a, the insoluble portion 3a and the insoluble portion 6a are brought into contact directly with each other. Since both of the insoluble portion 3a and the insoluble portion 6a are made of photoresist materials, affinity is high to make the degree of adhesion high. Therefore, it becomes possible to connect the insoluble portion 3a and the insoluble portion 6a strongly, thereby giving the electroforming mold 103 with high strength.
Further, in the third embodiment, in the process in
When the edge portion of the electrode 5a lies in the same plane as the edge face of the insoluble portion 3a, electric field concentrates on the edge portion of the upper face of the electrode 5a, which could lead to formation of an electroformed object with an increased thickness at the portion, but, by arranging it so as to recess from the edge face of the insoluble portion 3a by W5, it is possible to prevent concentration of the electrolysis and to allow the object to grow in a uniform thickness. Further, when the edge portion of the electrode 5a projects beyond the edge portion of the insoluble portion 3a, generation of curvature of the electrode 5a due to stress or formation of a “hollow” in the lower portion of the projecting electrode 5a during the electroforming could be lead, but, since it is arranged while being recessed from the edge portion of the insoluble portion 3a by W5, it is possible to prevent the “hollow” from being formed.
However, it is sufficient for the electrode 5a that it is formed on the insoluble portion 3a and has an exposed face, and position to be formed is not restricted. Accordingly, one edge of the electrode 5a may lie in the same plane as the edge face of the insoluble portion 3a, or may project beyond the edge face of the insoluble portion 3a. Further, the other edge of it may be in contact with the insoluble portion 6a.
Here, the electroforming mold 103 according to the embodiment will be described more specifically. For example, description will be given as an electroforming mold for use in manufacturing the gear 130 shown in
That is, the electroforming mold 103 in this case is formed so as to have a circular outer shape to surround the circumference of the gear 130, and the second through-hole 25 formed in the photoresist 6 constitutes the outer shape of the gear 130 when viewed from above. Further, the first through-hole 24 formed in the photoresist 3 is configured in such a shape that it can make a step 131a on the front edge side of plural cog portions 131.
In doing so, as shown in
In the electroforming mold 103 for manufacturing such gear 130, in order to electroform respective cog portions 131 shown in
In other words, when the electroforming mold 103 is viewed from above, as shown in
First, as shown in
On this occasion, if, as shown in
That is, there occurred such problem that the irradiated ultraviolet light 20a not only exposes the region of the photoresist 6 that is not hidden by the photo mask 4c to form the insoluble portion 6a, but a part of the ultraviolet light) 20a having transmitted through the photoresist 6 is reflected from the electrode 5a, thereby also exposing a part of the region hidden by the photo mask 4c (a region for forming the soluble portion 6b). Particularly, since the ultraviolet light 20a passing nearby the edge portion of the photomask 4c is diffracted by the edge portion to vary the incident angle, after being reflected from the electrode 5a, it easily exposed the region hidden by the photo mask 4c.
Consequently, it was intended, by the photo mask 4c, to form the insoluble portion 6a and the soluble portion 6b surly in an intended position while clearly sectionalizing the regions of the photoresist 6 to which the ultraviolet light 20a is exposed or unexposed, but the insoluble portion 6a was also formed in an unintended region. As the result, when the photoresist 6 was developed to remove the soluble portion 6b, for example, a convex portion in a line had been formed needlessly on the edge portion of the insoluble portion 6a. Accordingly, when a metal was precipitated through electroforming, a portion being in contact with the convex portion was concaved to manufacture a gear (electroformed component) 130 with a “streak” in a line on the outer surface thereof, as described above.
On the contrary, as shown in
As the result, a gear 130, which has a smoothed outer surface without a “streak” and the like, can be manufactured surely by an electroforming. Particularly, the gear 130 falls in a state that the outer face thereof is ground every time it repeats engagement with other gear through the cog portion 131, but, since a smoothened outer surface without a “streak” can be formed, slide resistance can be reduced as far as possible. Accordingly, it is possible to rotate the gear 130 more smoothly, as well as to enhance endurance.
Further, since the electrode 5a is formed so as to be separated from the aperture edge 24a of the first through-hole 24 by a constant distance W5, when a metal is precipitated near the aperture edge 24a, the metal is not brought into contact with the electrode 5a without any delay, thereby preventing convergence of electric field and preventing precipitation of the metal in a distorted shape. This makes it easy to precipitate the metal in a uniform thickness surely, and possible to carry out electroforming in accordance with the electroforming mold 103.
In this connection, it is beneficial to set a predetermined distance W6 between the electrode 5a and the photoresist 6 based on the thickness of the photoresist 6. For example, when the thickness of the photoresist 6 is increased, since the irradiating light 20a diffracted at the photo mask 4c enters toward a more soluble portion 6b side till it passes through the photoresist 6, it is preferred to set the predetermined distance W6 to be larger, thereby widening the spacing between the electrode 5a and the photoresist 6. In doing so, it is possible surely to prevent the reflection light reflected from the electrode 5a from being generated.
The electroforming mold 1002 shown in
In
In
As described above, since the electrodes 5ab and 5ac are separated from each other, each of the electrodes works only on the electroformed object 120a or 121a precipitated for the respective convex portions. Accordingly, even if the precipitation rate of the electroformed objects 120a and 121a at respective convex portions is not uniform, each of the electroformed objects 120a and 121a is precipitated independently and it is free of influence from the electroformed object 120a or 121a precipitated in the neighboring mold.
Lastly, in
Incidentally, when it is intended to make the electroformed object 120a and electroformed object 121a have the same intended thickness, thicknesses of the electroformed objects 120a and 121a are uniformed, for example, in a grinding process. Incidentally, when thickness control of the electroformed objects 120a and 121a is possible in the electroforming process, no grinding process may be carried out.
Here, in order to make a comparison with the electroforming mold 1002 shown in
That is, as shown in
First, as shown in
Further, as shown in
Accordingly, in the case where plural electroforming molds are configured to be arranged on the same substrate, when the electrodes of the neighboring electroforming molds are separated from each other as the electroforming mold 1002 shown in the fourth embodiment, the uniformly precipitated electroformed components 120 and 121 can be obtained.
An electroforming mold 1003 shown in
According to the electroforming mold 1003, as shown in
Accordingly, the case where each of the electrodes 5aa, 5ab, 5ac and 5ad is arranged while being separated from the insoluble portion 6a can also give the same effect as Example described in
Next, fifth embodiment of the method for manufacturing an electroforming mold according to the invention will be described. In this connection, in the fifth embodiment, the same parts as the constituent elements in the first embodiment are given the same symbol and description about them is omitted.
A different point between the fifth embodiment and the first embodiment is the point that, in the first embodiment, each of the photo mask 3 formed on the electroconductive layer 2 and the light-absorbing body 10 formed on the photo mask 3 is exposed separately, but that, in the fifth embodiment, the photo mask 3 and the light-absorbing body 10 are exposed simultaneously.
In other words, the method for manufacturing an electroforming mold of the embodiment is a method in which a process of forming a film of the electroconductive layer 2 on the upper face of the substrate 1, a process of forming the photoresist 3 on the upper face of the electroconductive layer 2, and a process for forming the light-absorbing body 10 on the upper face of the photoresist 3 are carried out, and then a process for exposing the light-absorbing body 10 through the photo mask 4b arranged above the light-absorbing body 10 is carried out. The latter process is the same as that in the first embodiment.
Hereinafter, these respective processes are described in detail.
First, as shown in
On this occasion, the electroconductive layer 2 is made of, for example, gold, silver, nickel or the like and is formed by a spattering method, a vacuum evaporation method or the like. In this connection, between the electroconductive layer 2 and the substrate 1, chromium, titanium or the like, which is not shown, may be interposed as an anchor metal in order to strengthen the adhesion force of the electroconductive layer 2. Further, when an electroconductive substrate such as stainless steel and aluminum is adopted as the substrate 1, the electroconductive layer 2 is not necessarily required.
The photoresist 3 is a negative type photoresist, or a chemical amplification type photoresist, and is formed by spin coating or the like. Particularly, when a structure with a high aspect ratio is to be produced, as the photoresist 3, use of a chemical amplification type photoresist based on an epoxy-type resin is desirable. Further, as the photoresist 3, one which is insoluble in a developer of the light-absorbing body 10 is used.
After forming the electroconductive layer 2 and the photoresist 3, as shown in
Then, as shown in
Subsequently, the light-absorbing body 10 alone is developed by using an alkaline developer containing, for example, TMAH (tetramethylammonium hydroxide). In this connection, when a chemical amplification type photoresist is used as the photoresist 3, it is subjected to PEB. Here, since the light-absorbing body 10 is of a positive type, the region exposed by the ultraviolet light 20b alone is removed. Accordingly, as shown in
Subsequently, as shown in
Then, as shown in
Subsequently, as shown in
By the irradiation of ultraviolet light, a state is achieved in which, as shown in
Lastly, the photoresists 3 and 6 are subjected to development to remove both of the insoluble portions 3b and 6b of the both photoresists 3 and 6. As the result, as shown in
As mentioned above, in the method for manufacturing an electroforming mold of the embodiment, different from the method described in the first embodiment, since the photoresist 3 and the light-absorbing body 10 are exposed at one time by a first irradiation of the ultraviolet light 20b, it is possible to reduce the number of the photo mask by one, as well as to reduce the process for arranging the photo mask by one process. Accordingly, the manufacturing time can be shortened and, simultaneously, the cost necessary for the photo mask can be lowered.
Further in the method according to the first embodiment, there was such requirement that, upon arranging the photomask 4b above the light-absorbing body 10, it must be registered on the basis of the position of the photomask 4a that had been arranged upon exposing the photoresist 3. This is done to allow the light-absorbing body 10 to be formed in a state of precise registration relative to the soluble portion 3b and the insoluble portion 3a.
On the contrary, in the embodiment, since the process in which the photoresist 3 is exposed by utilizing the photo mask 4a before forming the light-absorbing body 10 becomes unnecessary and the photoresist 2 and the light-absorbing body 10 can be exposed at one time, registration of the photomask 4b is unnecessary. Therefore, the manufacture becomes easier. Further, the insoluble portion 3a and the soluble portion 3b can be formed precisely at a targeted position, and the electroconductive layer 5 can be precisely divided according to an intended pattern to form the electrodes 5a. As the result, an electroformed component can be produced with high accuracy.
Next, a sixth embodiment of the method for manufacturing an electroforming mold according to the invention will be described. In the sixth embodiment, description will be given while exemplifying a case where an electroforming mold for use in the fourth embodiment is manufactured by the same manufacturing process as that in the aforementioned fifth embodiment.
In this connection, in the sixth embodiment, the same parts as the constituent elements in the fourth embodiment are given the same symbol and description about them is omitted.
First, as shown in
Then, after arranging the photo mask 140, the ultraviolet light 20b is irradiated from above through the photo mask 140 toward the light-absorbing body 10. This gives a state in which, as for the photoresist 3 and the light-absorbing body 10, regions that are not hidden by the photo mask 140 have been exposed by the ultraviolet light 20b. As the result, as for the photoresist 3, the exposed region becomes the insoluble portion 3a and the unexposed region with the help of the photo mask 140 becomes the soluble portion 3b.
Subsequently, only the light-absorbing body 10 is developed. Here, since the light-absorbing body 10 is of a positive type, only the region exposed by the ultraviolet light 20b is removed. Accordingly, as shown in
Subsequently, as shown in
Subsequently, as shown in
Incidentally, the soluble portions 3b having been hidden by the aforementioned photo masks 141 are kept in a state of being not hidden at this second round of exposure.
By the irradiation of the ultraviolet light 20a, the photoresist 6 goes into a state that regions not hidden by the two photo masks 150 have been exposed. Incidentally, since the photoresist 6 is of a negative type photoresist, the exposed region becomes the insoluble portion 6a, and the unexposed region with the help of the photo mask 150 becomes the soluble portion 6b.
In particular, since a portion that constituted the soluble portion 3b at the first exposure goes into an exposed state at this second round of irradiation of the ultraviolet light 20a, it varies from the soluble portion 3b to the insoluble portion 3a.
Lastly, the photoresists 3 and 6 are subjected to development to remove both of the insoluble portions 3a and 6a of both photoresists 3 and 6. As the result, as shown in
As mentioned above, according to the method for manufacturing an electroforming mold of the embodiment, since the photoresist 3 and the light-absorbing body 10 are exposed at one time by the first irradiation of the ultraviolet light 20b, even an electroforming mold having a complicated figure can be easily manufactured and, at the same time, each of the electrodes 5aa, 5ab, 5ac and 5ad and the first through-hole 24 can be manufactured at a targeted position with high accuracy.
In this connection, in the embodiment, the thickness of the electroconductive layer 5 is preferably thinned as far as possible. In doing so, strength of the reflected light from the electrodes 5aa, 5ab, 5ac and 5ad, which was described in the aforementioned third embodiment, can be lowered. As the result, when an electroformed component is manufactured by using the electroforming mold 1002 of the embodiment, it is possible to prevent a “streak” from being generated on the outer surface thereof as far as possible.
In this connection, technical scope of the invention is not restricted to the aforementioned embodiments, but various changes may be made to it within a range that does not depart from the point of the invention.
All the Examples having been described hitherto can also be practiced by replacing a negative type photoresist with a positive type resist with regard to the photoresist 3 and replacing a positive type photoresist with a negative type photoresist with regard to the light-absorbing body 10. In that case, as for the photoresist 6, either a negative type photoresist or a positive type resist may be selected.
When exposing the positive type photoresist 3, the photo mask 4a is arranged above a region for forming the insoluble portion 3a, so as to allow a region for forming the soluble portion 3b to be irradiated by the light. And, when exposing the negative type light-absorbing body 10, the photo mask 4b is arranged above a region for being removed at pattern formation, so as to allow a region for forming a pattern to be irradiated by the light. In exposure of the photoresist 6, when a negative type photoresist is selected, the photo mask 4c is arranged above the region for forming the soluble portion 6b, so as to allow a region for forming the insoluble portion 3a to be irradiated by the light, and, when a positive type photoresist is selected, the photo mask 4c is arranged above a region for forming the insoluble portion 6a, so as to allow a region for forming the soluble portion 6b to be irradiated by the light.
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2005-007052 | Jan 2005 | JP | national |
2005-203983 | Jul 2005 | JP | national |
2005-335328 | Nov 2005 | JP | national |
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