Patent Application
20240176229
The present application claims priority based on Japanese Patent Application No. 2021-054711 filed with the Japan Patent Office on Mar. 29, 2021, the entire disclosure of which is entirely incorporated herein by reference.
The present disclosure relates to a method for manufacturing an electroforming mold and a photomask.
For example, a structure having a minute shape such as a component of a timepiece is manufactured by electroforming (electroforming; a method for manufacturing, repairing, or replicating a metal product by an electroplating method). When a component (electroformed article) is manufactured by electroforming, a photoresist layer is formed on a substrate, and a pattern of a soluble portion and an insoluble portion is formed on the photoresist layer, thereby manufacturing an electroforming mold (see, for example, Patent Literature 1: JP 4550569 B2).
Examples of the electroforming mold using the pattern of a soluble portion and an insoluble portion include a formation method of emitting light using a photomask in which a pattern is formed by a light shielding portion and a light transmitting portion, and a formation method of irradiating a region corresponding to an insoluble portion by scanning laser light without using a photomask.
Meanwhile, there is a phenomenon in which a photoresist layer is slightly deformed in an exposure step or a post exposure bake (PEB) (baking after exposure/before development) step after exposure in the case of a chemically amplified resist, and a corner portion of an electroforming mold is blunted. That is, the corner portion has a rounded end, and the resolution (sharpness) decreases. For this reason, in an electroformed article manufactured using an electroforming mold, the reproducibility of the end shape of the corner portion may deteriorate.
The present disclosure has been made in view of the above circumstances, and an object is to provide a method for manufacturing an electroforming mold, and a photomask capable of preventing an end of a corner portion in a pattern of a photoresist layer from being blunted.
A first of the present disclosure is a method for manufacturing an electroforming mold. The method includes: forming a pattern including a soluble portion and an insoluble portion in a photoresist layer stacked on a substrate; removing the soluble portion to form a cavity, and when a corner portion is formed in the soluble portion, forming a soluble portion corner correction portion that is configured to suppress a decrease in sharpness of the corner portion of the soluble portion in a region facing the corner portion of the soluble portion across a vertex of the corner portion of the soluble portion.
A second of the present disclosure is a method for manufacturing an electroforming mold. The method includes forming a pattern comprising a soluble portion and an insoluble portion in a photoresist layer stacked on a substrate; removing the soluble portion to form a cavity; and when a corner portion is formed in the insoluble portion, forming an insoluble portion corner correction portion that is configured to suppress a decrease in sharpness of the corner portion in a region facing the corner portion across a vertex of the corner portion.
A third of the present disclosure is a photomask for forming a pattern including a soluble portion and an insoluble portion in a photoresist layer formed by being stacked on a substrate. The photomask is provided with a pattern including a light shielding portion and a light transmitting portion. When a corner portion is formed in the light shielding portion, a light shielding portion corner correction portion configured to suppress a decrease in sharpness of the corner portion of the light shielding portion is formed in a region facing the corner portion of the light shielding portion across a vertex of the corner portion of the light shielding portion.
A fourth of the present disclosure is a photomask used for forming a pattern including a soluble portion and an insoluble portion in a photoresist layer formed by being stacked on a substrate. The photomask is provided with a pattern comprising a light shielding portion and a light transmitting portion. When a corner portion is formed in the light transmitting portion, a light transmitting portion corner correction portion configured to suppress a decrease in sharpness of the corner portion of the light transmitting portion is formed in a region facing the corner portion of the light transmitting portion across a vertex of the corner portion of the light transmitting portion.
Hereinafter, an embodiment of a method for manufacturing an electroforming mold, and a photomask according to the present disclosure will be described with reference to the drawings.
Note that, in the method for manufacturing the electroformed article 200 illustrated in
In the method for manufacturing the electroformed article 200, as illustrated in
When the substrate main body 11 has conductivity, the conductive film 12 may not be provided. In addition, when the substrate main body 11 does not have conductivity and the conductive film 12 is not formed, the conductive film may be formed at least in the cavity portion 23 after a cavity portion 23 is formed
The photoresist layer 20 may be a positive resist or a negative resist. The positive resist includes a soluble portion and an insoluble portion. In the soluble portion of the positive resist, a portion where ultraviolet light (ultraviolet ray) is irradiated dissolves. The insoluble portion of the positive resist is a portion where the ultraviolet light (ultraviolet ray) is not irradiated. The negative resist includes an insoluble portion and a soluble portion. In the insoluble portion of the negative resist, a portion where the ultraviolet light (ultraviolet ray) is irradiated does not dissolve. The ultraviolet light (ultraviolet ray) is a portion where the ultraviolet light (ultraviolet ray) is not irradiated. Descriptions will be given on the assumption that the photoresist layer 20 in the method for manufacturing the electroformed article 200 illustrated in
In the method for manufacturing the electroformed article 200, the photomask 80 or photomask 180 is then disposed on the surface (upper surface in the drawing) side of the photoresist layer 20, and the photoresist layer 20 is irradiated with ultraviolet light L from above through the photomask 80 or photomask 180.
Each of the photomask 80 and the photomask 180 has a pattern including a light transmitting portion 81 that allows the ultraviolet light L to pass therethrough and a light shielding portion 82 that does not allow the ultraviolet light L to pass therethrough. The pattern forms an electroforming mold corresponding to the profile shape of the electroformed article 200.
When the ultraviolet light L is emitted through the photomasks 80, 180, a lower portion of the photoresist layer 20 below the light transmitting portion 81 becomes an insoluble portion 21 by being irradiated with the transmitted ultraviolet light L, and remains in a development process. On the other hand, a lower portion of the photoresist layer 20 below the light shielding portion 82 becomes a soluble portion 22 by not being irradiated with the shielded ultraviolet light L, and is removed in the development process.
Thus, the light shielding portion 82 of the photomask 80, 180 forms the soluble portion 22 in the photoresist layer 20, and the light transmitting portion 81 forms the insoluble portion 21 in the photoresist layer 20. Note that when the photoresist layer 20 is a positive resist, on the contrary, the light shielding portion 82 forms an insoluble portion in the photoresist layer 20, and the light transmitting portion 81 forms a soluble portion in the photoresist layer 20.
When the soluble portion 22 is removed by the development process, a portion where the soluble portion 22 existed becomes the cavity portion 23. The substrate 10 is brought into an exposed state in the cavity portion 23, and a pattern of the cavity portion 23 and the insoluble portion 21 becomes a mold (electroforming mold) for molding the electroformed article 200.
Then, in the cavity portion 23, metal such as nickel grows from the substrate 10 in an electroplating step, and the electroformed article 200 of metal such as nickel corresponding to the profile shape of the cavity portion 23 is manufactured. Note that when the substrate 10 is an insulator having no conductivity, it is sufficient if a conductive film is formed at least in the cavity portion 23 at this stage.
Here, descriptions will be given on the assumption that the photomask 180 used in the conventional method for manufacturing an electroforming mold has a pattern including a star-shaped light shielding portion 82 and a light transmitting portion 81 around the star-shaped light shielding portion 82 as illustrated, for example, in
The reason why the end of the corner portion 21a of the insoluble portion 21 becomes blunt and rounded as described above is presumed to be that the insoluble portion 21 shrinks due to crosslinking between molecules of the insoluble portion 21 at the time of exposure with the ultraviolet light L or at the time of post exposure bake (PEB) (baking after exposure/before development) after exposure in a case where the photoresist layer 20 is a chemically amplified resist.
Also, the reason why the end of the corner portion 23a of the cavity portion 23 becomes blunt and rounded is presumed to be that pulling occurs between the two insoluble portions 21 sandwiching the corner portion 23a of the cavity portion 23 due to shrinkage caused by crosslinking between the molecules, and the insoluble portions 21 in the region facing the corner portion 23a across the vertex 23b are attracted to the corner portion by the stress of the pulling.
As described above, when the end of the corner portion 23a of the cavity portion 23 becomes blunt or the end of the corner portion 21a of the insoluble portion 21 becomes blunt, the shape of the cavity portion 23 does not reproduce the shape of the intended design, and the dimensions of the electroformed article 200 manufactured by the electroforming mold formed with the pattern of the cavity portion 23 and the insoluble portion 21 is different from the dimension of the intended design.
On the other hand, as illustrated in
In the photomask 80, when a corner portion 82a (which is a portion bent at an angle less than 180 [degrees]) is formed in the light shielding portion 82, a light shielding portion corner correction portion 84 is formed in a region facing the corner portion 82a of the light shielding portion 82 across a vertex 82b of the corner portion 82a of the light shielding portion 82. The light shielding portion corner correction portion 84 suppresses a decrease in sharpness of the corner portion 82a of the light shielding portion 82.
Similarly to the light shielding portion 82, the light shielding portion corner correction portion 84 is a light shielding portion that does not allow the ultraviolet light to pass therethrough. That is, the light shielding portion corner correction portion 84 forms a soluble portion corner correction portion 24 which is a soluble portion (cavity) in the photoresist layer 20.
In addition,
For example, as illustrated in
In short, it is sufficient if the light shielding portion corner correction portion 84 removes the insoluble portions 21 attracted to the vicinity of the vertex 23b of the corner portion 23a in the region facing the corner portion 23a across the vertex 23b even in a case where pulling occurs due to shrinkage caused by crosslinking between the molecules between the two insoluble portions 21 sandwiching the corner portion 23a of the cavity portion 23 formed by the light shielding portion 82.
In a case where the light shielding portion corner correction portion 84 is a rectangle or a polygon, it is preferable that the vertex of the portion 84 is formed in the orientation (pose) facing the corner portion 82a across the vertex 82b to alleviate the stress generated in the two insoluble portions 21 sandwiching the corner portion 23a. However, the sides of the rectangle or the polygon of the light shielding portion corner correction portion 84 may be formed in the orientation facing the corner portion 82a across the vertex 82b.
The light shielding portion corner correction portion 84 may have a configuration in which the light shielding portion corner correction portion 84 contacts the light shielding portion 82, wherein the light shielding portion corner correction portion 84 contacts the vertex 82b of the corner portion 82a of the light shielding portion 82 or a configuration in which the light shielding portion corner correction portion 84 is separated from the light shielding portion 82 wherein the light shielding portion corner correction portion 84 is separated from the vertex 82b of the corner portion 82a of the light shielding portion 82. The light shielding portion corner correction portion 84 may have a configuration in which the light shielding portion corner correction portion 84 overlaps the vertex 82b of the corner portion 82a of the light shielding portion 82 and the light shielding portion corner correction portion 84 and the light shielding portion 82 are connected. When the light shielding portion corner correction portion 84 is separated from the vertex 82b of the corner portion 82a of the light shielding portion 82, the separation distance is preferably 10 [μm] or less.
In addition, in the photomask 80, as illustrated in
For example, as illustrated in
The light transmitting portion corner correction portion 85 has a configuration in which the light transmitting portion corner correction portion 85 contacts the light transmitting portion 81, wherein the vertex of the light transmitting portion corner correction portion 85 contacts the vertex 81b of the corner portion 81a of the light transmitting portion 81, or a configuration in which the light transmitting portion corner correction portion 85 and the light transmitting portion 81 are connected, wherein the vertex of the light transmitting portion corner correction portion 85 and the vertex 81b of the corner portion 81a overlap with each other.
In addition, it is preferable that the vertex of the rectangle or polygon of the light transmitting portion corner correction portion 85 is formed in the orientation facing the corner portion 81a across the vertex 81b to alleviate the stress generated in the corner portion 21a. However, the sides of the rectangle or the polygon of the light transmitting portion corner correction portion 85 may be formed in the orientation facing the corner portion 82a across the vertex 81b.
When an electroforming mold is manufactured in the step illustrated in
That is, even in a case where pulling occurs due to shrinkage caused by crosslinking between the molecules between the two insoluble portions 21 sandwiching the corner portion 23a of the cavity portion 23, the cavity is formed by the light shielding portion corner correction portion 84 in the region facing the corner portion 23a across the vertex 23b and the insoluble portion 21 (see the right-half region in
In addition, when the electroformed article 200 is manufactured in the step illustrated in
That is, pulling occurs between the corner portion 21a of the insoluble portion 21 and the insoluble portion corner correction portion 25 formed by the light transmitting portion corner correction portion 85 due to shrinkage caused by crosslinking between the molecules, and a vertex 21b of the corner portion 21a remains.
As a result, according to the method for manufacturing an electroforming mold using the photomask 80 of the present embodiment, a decrease in the sharpness of the end of the corner portion 23a of the cavity portion 23 is prevented or suppressed, and a decrease in the end of the corner portion 21a of the insoluble portion 21 is prevented or suppressed, so that the shape of the cavity portion 23 can be produced as the shape of the intended design.
Therefore, according to the method for manufacturing the electroforming mold using the photomask 80 of the present embodiment, it is possible to prevent or suppress a decrease in the sharpness of the corner portions 21a and 23a as compared with the method for manufacturing the electroforming mold using the conventional photomask 180. As a result, according to the method for manufacturing the electroformed article to which the method for manufacturing the electroforming mold of the present embodiment is applied, the dimensional accuracy of the manufactured electroformed article 200 can be improved as compared with the method for manufacturing the electroformed article to which the conventional method for manufacturing the electroforming mold is applied.
Note that, in the electroforming mold manufactured by the method for manufacturing the electroforming mold using the photomask 80 of the present embodiment, the insoluble portion corner correction portion 25 is formed in a portion corresponding to the light transmitting portion corner correction portion 85. Therefore, in the electroformed article 200 manufactured using the electroforming mold having the insoluble portion corner correction portion 25, as illustrated in
That is, as illustrated in
Therefore, the weight of the electroformed article 200 can be reduced by the amount of the cavity 210 as compared with an electroformed article manufactured by the conventional manufacturing method by which the cavity 210 is not formed. Accordingly, energy can be saved as a result of the weight reduction when the electroformed article 200 is used as a moving object.
In addition, the electroformed article 200 having the corner portion 220 bent over the angle 180 [degrees] and formed with the cavity 210 can hold lubricating oil 300 in the cavity 210 and at a corner around the cavity 210, and the like when the lubricating oil 300 is applied to a surface 230 of the electroformed article 200, for example, as illustrated in
Therefore, when the surface 230 of the electroformed article 200 slides with another object 400, the lubricating oil 300 held in the cavity 210 can be supplied to the sliding surface (the same as the surface 230) between the electroformed article 200 and the other object 400 to hold the lubricating oil 300 on the sliding surface (the surface 230), and the durability of the sliding surface (the surface 230) between the electroformed article 200 and the other object 400 can be improved (the life can be extended).
In addition, for example, as illustrated in
In addition, for example, as illustrated in
Therefore, in a case where the other object 400 is advanced toward the surface 230 of the electroformed article 200 in a direction shown with an arrow to bond the electroformed article 200 and the other object 400, the adhesive 500 held in the cavity 210, at the corner around the cavity 210, or the like is supplied between the electroformed article 200 and the other object 400. Accordingly, the adhesive 500 between the electroformed article 200 and the other object 400 can be sufficiently supplied, and the electroformed article 200 and the other object 400 can be firmly bonded.
In addition, for example, as illustrated in
Therefore, the other object 400 having the width W2 (≈W1) substantially the same as the width W1 or the width W2 (>W1) wider than the width W1 can be inserted into the recess 250 having the width W1 in the electroformed article 200.
In the method for manufacturing the electroforming mold of the present embodiment, the photoresist layer 20 to be exposed with the ultraviolet light L using the photomask 80 is a negative resist. However, in the method for manufacturing the electroforming mold according to the present disclosure, the photoresist layer 20 to be exposed with the ultraviolet light L using the photomask 80 may be a positive resist.
In this case, the light shielding portion 82, which is illustrated in
For this reason, when a photoresist layer of a positive resist is used in the method for manufacturing the electroforming mold of the present disclosure, it is sufficient if the light shielding portion corner correction portion 84 is configured to be in contact with or connected to the light shielding portion 82, and the light transmitting portion corner correction portion 85 is configured to be located close to the light transmitting portion 81 at a distance of 0 to 10 [μm], or separated from the light transmitting portion 81, or connected to the light transmitting portion 81.
In the method for manufacturing the electroforming mold, and the photomask 80 of the embodiment described above, the electroforming mold with the pattern including the corner portion 23a of the soluble portion 22 (cavity portion 23) and the corner portion 21a of the insoluble portion 21 in the photoresist layer 20 is formed. However, the method for manufacturing the electroforming mold and the photomask according to the present disclosure may form a pattern including only the corner portion of the soluble portion (cavity) or may form a pattern including only the corner portion of the insoluble portion in the photoresist layer.
The method for manufacturing the electroforming mold of the present embodiment is the method for manufacturing the electroforming mold in which the electroforming mold is formed with the pattern of the soluble portion 22 and the insoluble portion 21 in the photoresist layer 20 which is the negative resist (in the case of the positive resist photoresist layer 20, the soluble portion and the insoluble portion are reversed) using the photomask 80 formed with the pattern having the light shielding portion 82 for shielding the ultraviolet light L and the light transmitting portion 81 for transmitting the ultraviolet light L. However, the method for manufacturing the electroforming mold according to the present disclosure is not limited to the method for exposing the photoresist layer using the photomask.
That is, the method for manufacturing the electroforming mold according to the present disclosure may be a manufacturing method for manufacturing the electroforming mold with the pattern including the soluble portion and the insoluble portion by scanning a region (soluble portion and soluble portion corner correction portion in positive resist, and insoluble portion and insoluble portion corner correction portion in negative resist) of the photoresist layer to be exposed through the light transmitting portion of the photomask with, for example, laser light without using the photomask and not irradiating a region (insoluble portion and insoluble portion corner correction portion in positive resist, and soluble portion and soluble portion corner correction portion in negative resist) of the photoresist layer to be shielded by the light shielding portion of the photomask with the laser light.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021054711 | Mar 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/013484 | 3/23/2022 | WO |
