Master disc for electroforming, method for manufacturing master disc for electroforming, and metallic molded product manufacturing method

Abstract

To provide a master disc for electroforming for manufacturing a metallic molded product having an opening according to arrangement of a mask by electroforming that can be used a plurality of times, a method for manufacturing the master disc for electroforming, and a method for manufacturing the metallic molded product.SOLUTION: In a master disc for electroforming, a method for manufacturing the master disc for electroforming, and a metallic molded product manufacturing method, the master disc for electroforming comprises a semiconductor substrate and an insulative mask provided at a part of a surface of the semiconductor substrate. The mask is formed from an insulation layer formed by insulation treatment on the surface of the semiconductor substrate, a portion without provision of a mask on the surface of the semiconductor substrate is an alloy layer containing constituent elements of the semiconductor substrate and metal elements diffused into the semiconductor substrate, and the mask projects with respect to a surface of the alloy layer.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an electroforming master, a method for manufacturing an electroforming master, and a method for manufacturing a metal molded product. [Background technology]

[0002] A metal molding manufacturing method is known that uses electroforming technology to manufacture a metal molding having a plurality of openings (see, for example, Patent Document 1). The metal molding manufacturing method described in Patent Document 1 uses an electroforming master in which a non-conductive mask is formed on part of a substrate having a conductive surface, and includes an electroforming step in which a metal layer is grown on the conductive surface immersed in an electroforming solution, and openings are formed at positions corresponding to the mask, and by performing the electroforming step, a metal molding having openings is manufactured.

[0003] In Patent Documents 1 and 2, a nozzle plate used in the recording head of an inkjet printer is manufactured as a metal molded product. The nozzles eject ink to record dots corresponding to pixels, which are components of the image to be printed.

[0004] A nozzle plate is a thin metal plate in which a plurality of openings that function as nozzles for ejecting ink are arranged one-dimensionally or two-dimensionally. To form the plurality of openings arranged in this manner, Patent Documents 1 and 2, etc., use an electroforming master in which a plurality of masks are arranged one-dimensionally or two-dimensionally on the surface of a conductive substrate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 08-142334 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-23792 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Documents 1 and 2, a photosensitive resin is used as a mask, and after a metal molded product is produced by electroforming using an electroforming master, both the mask and the electroforming master are peeled off when the metal molded product is peeled off from the electroforming master. As a result, an electroforming master equipped with a mask cannot be used multiple times.

[0007] If an electroforming master can be reused multiple times, the manufacturing process for metal molded products can be made more efficient and costs can be reduced.

[0008] The present disclosure has been made in consideration of the above circumstances, and aims to provide an electroforming master for producing a metal molded product by electroforming, having openings corresponding to the arrangement of a mask, which can be used multiple times. Another object of the present disclosure is to provide a method for manufacturing an electroforming master that can be reused multiple times, and a method for manufacturing a metal molded product using the electroforming master. [Means for solving the problem]

[0009] The electroforming master of the present disclosure includes a semiconductor substrate and an insulating mask provided on a portion of the surface of the semiconductor substrate; The mask is made of an insulating layer formed by insulating the surface of a semiconductor substrate, a portion of the surface of the semiconductor substrate where the mask is not provided is an alloy layer containing a constituent element of the semiconductor substrate and a metal element diffused into the semiconductor substrate; The mask protrudes above the surface of the alloy layer.

[0010] The insulating layer is preferably an oxide film which is an oxide of a constituent element of the semiconductor substrate, a nitride film which is a nitride of the constituent element, or an oxynitride film which is an oxynitride of the constituent element.

[0011] The alloy layer is preferably a thermally diffused alloy layer obtained by thermally diffusing a metal element into the semiconductor substrate.

[0012] Preferably, the semiconductor substrate is a silicon substrate, the insulating layer is a silicon oxide film, and the alloy layer is mainly composed of silicon and a metal element.

[0013] The metal element is preferably nickel, tantalum or chromium.

[0014] The method for manufacturing an electroforming master according to the present disclosure includes the steps of: forming a resist pattern on an insulating layer of a semiconductor substrate having an insulating layer formed on its surface by an insulating treatment; a step of etching the insulating layer using the resist pattern as a mask to form a mask made of the insulating layer; forming a metal layer on a surface of a semiconductor substrate with a mask; a step of heat-treating the semiconductor substrate having the metal layer to diffuse metal elements constituting the metal layer from the surface of the semiconductor substrate into the semiconductor substrate; and removing the metal layer remaining on the surface of the semiconductor substrate.

[0015] In the step of forming the metal layer, it is preferable to remove a native oxide film formed on the surface of the semiconductor substrate before forming the metal layer in a film forming apparatus for forming the metal layer.

[0016] In the step of forming the metal layer, the metal layer is formed by a sputtering method, and the native oxide film is preferably removed by reverse sputtering the surface of the semiconductor substrate.

[0017] It is preferable to use a silicon substrate as the semiconductor substrate.

[0018] The method for manufacturing a metal molded product using an electroforming master according to the present disclosure includes the steps of: an electroforming step in which, while the electroforming master is immersed in an electroforming solution, a current is passed through the alloy layer, causing a metal to precipitate from the electroforming solution and grow a metal layer on the surface of the alloy layer, and openings are formed at positions corresponding to the mask, thereby forming a metal molded product having openings; a peeling step of peeling the metal molded object from the surface of the alloy layer; a cleaning step of cleaning the electroforming master using sulfuric acid / hydrogen peroxide, sulfamic acid, or ferric chloride after the peeling step; This process is repeated to produce multiple metal molded products using one electroforming master. [Effects of the Invention]

[0019] According to the present disclosure, it is possible to provide an electroforming master that can be used multiple times and is used to produce, by electroforming, a metal molded product having openings corresponding to the arrangement of a mask. Furthermore, the present disclosure can provide a method for manufacturing an electroforming master that can be used multiple times, and a method for manufacturing a metal molded product using the electroforming master. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view showing an example of a metal molded product. [Figure 2] FIG. 2 is a plan view showing an electroforming master. [Figure 3] FIG. 2 is a cross-sectional view of a portion of an electroforming master. [Figure 4] 1A to 1C are diagrams illustrating a manufacturing process of an electroforming master. [Figure 5] 1A to 1C are diagrams illustrating a part of the manufacturing process of an electroforming master. [Figure 6] 1A to 1C are diagrams illustrating a manufacturing process of a metal molded product. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0022] <Metal moldings> 1 is a diagram showing an example of a metal molded product having an opening produced by a method for producing a metal molded product according to an embodiment using an electroforming master according to an embodiment. In this example, the metal molded product is a nozzle plate 10 used in a recording head of an inkjet printer.

[0023] The nozzle plate 10 is a plate-like member formed of electroformed metal such as nickel (Ni) and having a rectangular planar shape. The nozzle plate 10 has a plurality of substantially circular openings 12 (hereinafter referred to as nozzles 12) arranged two-dimensionally and functioning as nozzles. The nozzles 12 are formed in a substantially circular shape, and their diameter D is, for example, 100 μm or less, preferably 20 μm to 50 μm. In the recording head, the nozzle plate 10 is disposed with its long dimension corresponding to the main scanning direction X of the inkjet printer and its short dimension corresponding to the sub-scanning direction Y. The length of the nozzle plate 10 in the main scanning direction is, for example, 100 mm, and its length in the sub-scanning direction is, for example, 40 mm. In this example, the nozzle plate 10 is provided with eight nozzle rows arranged in the sub-scanning direction Y, each row including 130 nozzles 12 arranged at regular intervals in the main scanning direction X.

[0024] <Electroforming master> FIG. 2 is a plan view showing a portion of an embodiment of an electroforming master 20 used to manufacture the nozzle plate 10, and FIG. 3 is a cross-sectional view of the portion of the electroforming master 20 shown in FIG. 2 taken along line III-III.

[0025] The electroforming master 20 includes a semiconductor substrate 21 and an insulating mask 23 provided on a portion of the surface 21S of the semiconductor substrate 21. The mask 23 is provided to form openings in the metal molded product (here, the nozzles 12 of the nozzle plate 10). On the surface of the semiconductor substrate 21, the portion where the mask 23 is not provided is an alloy layer 21a containing the constituent elements of the semiconductor substrate 21 and a metal element. The alloy layer 21a is conductive, and during electroforming using the electroforming master 20, a metal layer that will become the nozzle plate 10 grows on the surface of the alloy layer 21a.

[0026] The masks 23 are formed in locations corresponding to the nozzle formation positions in order to form the nozzles 12 provided in the nozzle plate 10. In this example, the masks 23 are circular. Because the masks 23 are insulating, metal does not grow in the areas covered by the masks 23, and these become openings, through which the nozzles 12 are formed. In this example, corresponding to the arrangement pitch and number of the nozzles 12 in the nozzle plate 10 described above, 130 masks 23 in 8 rows are formed in an area of ​​100 mm x 40 mm on the electroforming master 20. The diameter DM of the masks 23 is larger than the diameter D of the nozzles 12, and is, for example, 150 μm to 200 μm. The thickness of the masks 23 is, for example, 2 μm.

[0027] The mask 23 is composed of an insulating layer formed by an insulating treatment on the surface of the semiconductor substrate 21. The insulating treatment on the surface of the semiconductor substrate 21 is a treatment in which elements that bond with semiconductor constituent elements to form an insulator, such as oxygen, nitrogen, or oxygen and nitrogen, are diffused into the surface of the semiconductor substrate 21. Specific examples of such treatments include thermal diffusion treatment and ion implantation treatment using ion beam mixing. In the case of thermal diffusion treatment, for example, the semiconductor substrate 21 is heat-treated in a gas containing oxygen, a gas containing nitrogen, or a gas containing oxygen and nitrogen, thereby thermally diffusing oxygen, nitrogen, or oxygen and nitrogen into the surface layer of the semiconductor substrate 21. In the case of ion implantation treatment, for example, oxygen ions, nitrogen ions, or oxygen ions and nitrogen ions are implanted into the surface of the semiconductor substrate 21 as an ion beam and diffused into the surface layer of the semiconductor substrate 21. By such treatment, the semiconductor elements that constitute the semiconductor substrate 21 are oxidized, nitrided, or oxynitrided in the surface layer of the semiconductor substrate 21, thereby forming oxides, nitrides, or oxynitrides of the semiconductor elements, thereby providing insulation. That is, the insulating layer formed by the insulating treatment on the surface of semiconductor substrate 21 is a region insulated by the insulating treatment in the surface layer of semiconductor substrate 21. The insulating layer formed by the insulating treatment is preferably an oxide, nitride, or oxynitride of the constituent elements of semiconductor substrate 21. The insulating layer formed by the insulating treatment is preferably a thermal oxide film which is an oxide of the constituent elements of semiconductor substrate 21 formed by thermal diffusion treatment, a thermal nitride film which is a nitride of the constituent elements of semiconductor substrate 21, or a thermal oxynitride film which is an oxynitride of the constituent elements of semiconductor substrate 21.

[0028] As described above, the mask 23 in the electroforming master 20 comprises an insulating layer formed by forming and patterning an insulating region on the surface of the semiconductor substrate 21 through atomic diffusion into the surface of the semiconductor substrate 21. The mask 23 is obtained by patterning the insulating layer formed by atomic diffusion into the surface of the semiconductor substrate 21 (i.e., the insulating region on the surface of the semiconductor substrate 21). That is, in this embodiment, the mask 23 is not formed from an insulating layer formed on the surface of the semiconductor substrate 21 by chemical vapor deposition, physical vapor deposition, or the like.

[0029] However, in this specification, the phrase "the mask is composed of an insulating layer (referred to as a "first insulating layer" in this paragraph) formed by insulating the surface of the semiconductor substrate" does not limit the mask to one composed only of the first insulating layer, but means that the mask is composed primarily of the first insulating layer. "Mainly" means that the first insulating layer occupies at least 80% of the thickness of the mask 23 in the direction perpendicular to the surface of the semiconductor substrate 21 from the semiconductor substrate 21 side. Therefore, the mask 23 may have a laminated structure including a second insulating layer on the first insulating layer that has good adhesion to the first insulating layer. Specifically, the mask 23 may further include an insulating layer (hereinafter referred to as the second insulating layer) formed by vapor deposition or the like on the first insulating layer (e.g., a thermal oxide film) formed by insulating the surface of the semiconductor substrate 21. In this case, it is preferable that the first insulating layer and the second insulating layer be composed of the same constituent elements from the viewpoint of adhesion.

[0030] Examples of the semiconductor substrate 21 include a silicon (Si) substrate and a germanium (Ge) substrate, with a silicon substrate being particularly preferred. The semiconductor substrate 21 may be either an n-type or a p-type, and may be an intrinsic semiconductor containing no impurities. When the semiconductor substrate 21 is a silicon substrate, the constituent element is silicon, and the oxide, nitride, and oxynitride of the constituent element are silicon oxide, silicon nitride, and silicon oxynitride, respectively.

[0031] The alloy layer 21a is a layer formed by diffusing metal elements into the surface layer of the semiconductor substrate 21, and includes the constituent elements of the semiconductor substrate 21 and the metal elements diffused into the semiconductor substrate 21. The proportion of the constituent elements of the semiconductor substrate 21 and the metal elements in the total elements constituting the alloy layer 21a is preferably 80 at % or more, and more preferably 90 at % or more. As shown in FIG. 3 , the surface layer of the semiconductor substrate 21 has a region where the alloy layer 21a is formed and a region where it is not formed. The surface 21S of the semiconductor substrate 21 is a substantially flat surface and is composed of an alloy layer surface 21aS and a semiconductor surface 21bS. The alloy layer surface 21aS is the surface of the region where the alloy layer 21a is formed, and the semiconductor surface 21bS is the surface of the region where the alloy layer 21a is not formed. Since the mask 23 is formed on the flat surface 21S of the semiconductor substrate 21, the mask 23 protrudes from the surface of the alloy layer 21a. The portion of semiconductor substrate 21 that comes into contact with mask 23 includes a region where alloy layer 21a is not formed. Basically, the portion that comes into contact with mask 23 coincides with semiconductor surface 21bS where alloy layer 21a is not formed, but it is acceptable for mask 23 to include a partial alloy region inside from the periphery thereof.

[0032] Alloy layer 21a is a region alloyed by diffusing metal elements into the surface layer of semiconductor substrate 21, and is not a film formed on semiconductor substrate 21. When semiconductor substrate 21 is a silicon substrate, alloy layer 21a is mainly composed of silicon and metal elements. Here, "mainly composed of silicon and metal elements" means that the proportion of silicon and metal elements among all elements constituting alloy layer 21a is 80 at % or more.

[0033] The alloy layer 21a can be formed, for example, by forming a metal layer on the semiconductor surface of the semiconductor substrate 21 and then performing heat treatment to diffuse metal elements from the metal layer into the surface layer of the semiconductor substrate 21 (see the method for manufacturing an electroforming master described below). The alloy layer 21a can also be formed by implanting metal ions as an ion beam into the semiconductor surface of the semiconductor substrate 21 and diffusing them into the surface layer of the semiconductor substrate 21. It is particularly preferable that the alloy layer 21a be a thermally diffused alloy layer.

[0034] Examples of metals that can be alloyed with the constituent elements of the semiconductor substrate 21 include nickel (Ni), tantalum (Ta), chromium (Cr), cobalt (Co), molybdenum (Mo), palladium (Pd), tungsten (W), platinum (Pt), titanium (Ti), vanadium (V), niobium (Nb), hafnium (Hf), zirconium (Zr), and alloys thereof, with nickel being particularly preferred. When the semiconductor substrate 21 is a silicon substrate and the alloying metal is nickel, the alloy layer 21a is nickel silicide.

[0035] In the electroforming master 20 described above, the mask 23 is made of an insulating layer formed by insulating the surface of the semiconductor substrate 21. This ensures high adhesion to the semiconductor substrate 21, preventing the mask 23 from peeling off when the electroformed metal molded product is peeled off. Therefore, when manufacturing multiple metal molded products, it is not necessary to redo the formation of the mask 23. Because the mask 23 protrudes above the surface 21aS of the alloy layer 21a, it is highly functional as a mask for forming openings in metal molded products such as the nozzles 12 of the nozzle plate 10. Variations in opening diameter can be suppressed without the need to perform a process of forming a resist mask on a thermal oxide film, as in JP-A-08-142334.

[0036] Because alloy layer 21a is an alloy layer formed by diffusing metal elements into the surface layer of semiconductor substrate 21 and containing metal elements as its main components, it is not peeled off along with the metal molded product, which is the electroformed product, but remains as part of semiconductor substrate 21. Therefore, not only is it not necessary to redo the formation of mask 23 on semiconductor substrate 21, but electroforming master 20 can be used multiple times without redoing the formation of alloy layer 21a. This improves the efficiency of the manufacturing process for metal molded products and reduces manufacturing costs.

[0037] Even if the mask 23 has a layered structure including an insulating layer (first insulating layer) formed by insulating the surface of the semiconductor substrate 21 and another insulating layer (second insulating layer) formed thereon by vapor deposition or other methods, if the second insulating layer has good adhesion to the first insulating layer, it will remain on the electroforming master 20 when the metal molded product is peeled off, thereby achieving the same effect as described above. If the thickness of the first insulating layer is 80% or more of the thickness of the mask 23, the adhesion between the first insulating layer and the second insulating layer can be improved. Furthermore, if the thickness of the first insulating layer is 80% or more of the thickness of the mask 23, even if the second insulating layer peels off from the first insulating layer (i.e., from the electroforming master), the first insulating layer will maintain the function of the mask 23, allowing the electroforming master 20 to be reused without having to re-form the mask 23. However, when a second insulating layer is provided, materials and processes for forming the second insulating layer are required, and therefore, from the viewpoint of reducing the manufacturing costs of the electroforming master and improving the efficiency of the manufacturing process, it is more preferable that the mask 23 be composed only of an insulating layer formed by insulating treatment on the surface of the semiconductor substrate 21.

[0038] Furthermore, since the electroforming master 20 uses a semiconductor substrate 21 as the main body, it has high resistance to the chemicals used to dissolve electroformed residues, which are used after the production of one metal molded product and before the production of the next metal molded product, when the metal molded product described below is repeatedly produced.

[0039] <Method of manufacturing electroforming master> As one embodiment of the method for manufacturing an electroforming master according to the present disclosure, a method for manufacturing the electroforming master 20 will be described with reference to Figures 4 and 5. Figure 4 shows the manufacturing steps, and Figure 5 shows a preferred example of one of the steps shown in Figure 4.

[0040] First, in step ST1, a semiconductor substrate 21 is prepared, which has an insulating layer 22 formed on its surface by an insulating treatment. For example, the semiconductor substrate 21 is subjected to a heat treatment in a gas containing oxygen, thereby diffusing oxygen into the surface layer of the semiconductor substrate 21, thereby forming the insulating layer 22 on the surface of the semiconductor substrate 21. A commercially available thermally oxidized silicon wafer or the like may also be prepared.

[0041] Next, in step ST2, a resist film 30 is formed on the insulating layer 22 of the semiconductor substrate 21 having the insulating layer 22, and exposure is performed using a pattern forming mask (not shown) to form a resist pattern 31 as shown in step ST3. In this way, steps ST2 to ST3 are steps of forming the resist pattern 31 on the insulating layer 22 of the semiconductor substrate 21 having the insulating layer 22.

[0042] As shown in step ST4, the insulating layer 22 is etched using the resist pattern 31 as a mask to form a mask 23 made of the insulating layer 22 as shown in step ST5. In step ST4, arrow E schematically indicates an etching gas during dry etching.

[0043] Next, in step ST6, a metal layer 25 is formed on the surface of the semiconductor substrate 21 provided with the mask 23. The method for forming the metal layer 25 is not particularly limited, but it is preferably formed by sputtering. The thickness of the metal layer 25 is preferably 5 nm or more and 200 nm or less, and more preferably 10 nm or more and 100 nm or less.

[0044] Thereafter, in step ST7, the semiconductor substrate 21 with the metal layer 25 is heat-treated to diffuse the metal elements constituting the metal layer 25 from the surface of the semiconductor substrate 21 into the semiconductor substrate 21. That is, a thermal diffusion process is performed in which the semiconductor substrate 21 is heated using a heating device 27 to thermally diffuse the metal elements into the semiconductor substrate 21. As a result, the metal elements are diffused into the surface layer of the semiconductor substrate 21, and the surface layer of the semiconductor substrate 21 is alloyed to form an alloy layer 21a. The alloy layer 21a is formed directly below the portion of the metal layer 25 that is in contact with the semiconductor substrate 21. Although the alloy layer 21a is hardly formed directly below the mask 23, some of the metal elements may diffuse directly below the periphery of the mask 23. Furthermore, the metal elements of the metal layer 25 on the mask 23 are hardly diffused into the mask 23, and the metal layer 25 on the mask 23 is maintained even after heating. Examples of the heating device 27 include a hot plate and a rapid thermal processing (RTA) device. The heating atmosphere is preferably a vacuum or an inert gas atmosphere such as nitrogen or argon to prevent oxidation of the metal layer. Conditions such as heating temperature and time may be appropriately selected depending on the metal element used. For example, when nickel is used as the metal layer and silicon is used as the semiconductor substrate, the heating temperature on a vacuum hot plate (MSA Factory PH222 Custom) is preferably 200°C or higher and 700°C or lower, more preferably 250°C or higher and 400°C or lower. The heating time is preferably 1 minute or higher and 60 minutes or lower, more preferably 5 minutes or higher and 20 minutes or lower.

[0045] After the thermal diffusion treatment, in step ST8, the metal layer 25 remaining on the surface of the semiconductor substrate 21 is removed. Specifically, by cleaning with a mixed solution of sulfuric acid and hydrogen peroxide (for example, SH-303 manufactured by Kanto Chemical) 28, the metal layer 25 on the mask 23 of the semiconductor substrate 21 and the metal layer 25 formed on the portions other than the mask 23 that have not diffused into the semiconductor substrate 21 and remain on the surface are removed. Note that, although oxides of metal elements and semiconductor substrate elements may be formed on the surface after cleaning, this is not a problem as long as it does not affect the electroforming process.

[0046] In this manner, the master 20 for electroforming onto the surface of the semiconductor substrate 21 can be produced as shown in step ST9.

[0047] 5 shows a preferred embodiment of the step of forming the metal layer 25 in step ST6. The surface of a semiconductor substrate 21, such as a silicon substrate, may be oxidized in the atmosphere, forming a native oxide film. If a native oxide film is formed, even if a thermal diffusion process is performed after the formation of the metal layer 25, the native oxide film acts as a barrier, preventing diffusion of metal elements into the semiconductor substrate 21 and preventing the formation of the alloy layer 21a. Therefore, if a native oxide film is formed on the surface of the semiconductor substrate 21, it is preferable to remove the native oxide film from the surface of the semiconductor substrate 21 before forming the metal layer 25 on the surface of the semiconductor substrate 21. Methods for removing the native oxide film include a method of cleaning the substrate by irradiating it with an ion beam and reverse sputtering.

[0048] As a specific procedure, a case where the metal layer 25 is formed by sputtering will be described.

[0049] As shown in step ST60 of FIG. 5, the semiconductor substrate 21 with the mask 23 is set in a sputtering film-forming apparatus 40 with a target T for forming the metal layer 25.

[0050] Then, as shown in step ST61, a native oxide film is removed by reverse sputtering the surface of the semiconductor substrate 21 before forming the metal layer 25. In step ST61, the direction of the arrow indicates the traveling direction of the sputtered ions Ar.

[0051] After the native oxide film is removed, the target T is sputtered to form the metal layer 25, as in step ST62.

[0052] In this way, after the native oxide film is removed, the metal layer 25 is formed in the sputtering film formation apparatus 40 without exposing the semiconductor substrate 21 to the atmosphere. This allows the metal elements to be reliably diffused into the semiconductor substrate 21 in the subsequent thermal diffusion step.

[0053] <Metal molded product manufacturing method> An embodiment of the method for manufacturing a metal molded product according to the present disclosure using the electroforming master 20 will be described with reference to Fig. 6. Fig. 6 shows the steps for manufacturing a nozzle plate 10 as a metal molded product.

[0054] With the electroforming master 20 immersed in the electroforming liquid, a current is passed through the alloy layer 21a, and a metal layer is grown on the surface of the alloy layer 21a using metal precipitated from the electroforming liquid (electroforming steps ST11-ST12). The electroforming steps ST11-ST12 are performed with the electroforming master 20 immersed in the electroforming liquid contained in an electroforming tank (not shown) by a holding mechanism (not shown).

[0055] In the electroforming process ST11, a metal layer 11 grows on the surface of the alloy layer 21a, while no metal is deposited on the surface of the insulating mask 23, and the metal layer 11 does not grow. The metal layer 11 gradually grows on the surface of the alloy layer 21a. When the thickness of the grown metal layer 11 subsequently exceeds the thickness of the mask 23, the metal layer 11 grows from the surface of the previously grown metal layer 11 toward the mask 23, covering the edge of the mask 23. As the metal layer 11 grows from the edge toward the center of the mask 23, an opening is formed in the metal layer 11, with the opening center located approximately at the center of the mask 23. This opening becomes the nozzle 12. As the thickness of the metal layer 11 increases, the metal layer 11 grows toward the center of the mask 23, gradually reducing the opening diameter of the nozzle 12. The diameter of the mask 23 is determined so that the nozzle 12 will have the desired opening diameter when the metal layer 11 is grown to the desired thickness. On the mask 23, the growth of the metal layer 11 progresses closer to the surface of the alloy layer 21a. Therefore, as shown in step ST12 of FIG. 6, the opening diameter of the nozzle 12 becomes smaller as it approaches the surface of the alloy layer 21a and becomes larger as it moves away from the surface of the alloy layer 21a, and the cross section of the metal layer 11 constituting the inner wall surface of the nozzle 12 becomes arc-shaped. For example, the opening diameter of the nozzle 12 closer to the surface of the alloy layer 21a is set as a reference for the target opening diameter of the nozzle 12. Then, the diameter of the mask 23 is determined so that the opening diameter of the reference nozzle 12 becomes the target opening diameter. The thickness of the metal layer 11 is, for example, about 50 μm.

[0056] Next, the nozzle plate 10 made of the metal layer 11 deposited by electroforming is peeled off from the surface of the alloy layer 21a, i.e., from the electroforming master 20 (peeling step ST13). At this time, the mask 23 is not peeled off from the semiconductor substrate 21, but remains on the semiconductor substrate 21. In this way, the nozzle plate 10 can be manufactured by electroforming using the electroforming master 20.

[0057] After the peeling step ST13, the electroforming master 20 from which the nozzle plate 10 has been peeled is washed with a sulfuric acid / hydrogen peroxide solution mixture 28 (cleaning step ST14). Note that sulfamic acid or ferric chloride may be used as the cleaning liquid instead of the sulfuric acid / hydrogen peroxide solution mixture. Note that the electroforming master 20 after the peeling step is returned to the electroforming master 20 before electroforming by the cleaning step ST14.

[0058] By repeating the electroforming steps ST11 and ST12, the peeling step ST13, and the cleaning step ST14, a single electroforming master 20 can be used to manufacture a plurality of nozzle plates 10, which are metal molded products.

[0059] The electroforming master 20 includes a semiconductor substrate 21, a mask 23 formed by insulating and patterning a portion of the semiconductor substrate 21, and an alloy layer 21a formed by alloying the surface of the semiconductor substrate 21. With this configuration, the mask 23 and the alloy layer 21a are not peeled off when the metal molded product is peeled off after electroforming. Then, in the cleaning step ST14, a cleaning liquid such as a sulfuric acid / hydrogen peroxide solution mixture 28 can remove only the electroformed product residue and deposits remaining on the surface of the electroforming master 20 after peeling, without corroding the electroforming master 20. Thereafter, the electroforming master 20 can be repeatedly used to produce multiple metal molded products without requiring treatments such as reforming the mask 23 or imparting conductivity.

[0060] The following additional notes are provided regarding the above-described embodiments.

[0061] (Appendix 1) a semiconductor substrate and an insulating mask provided on a portion of a surface of the semiconductor substrate; The mask is made of an insulating layer formed by insulating the surface of a semiconductor substrate, a portion of the surface of the semiconductor substrate where the mask is not provided is an alloy layer containing a constituent element of the semiconductor substrate and a metal element diffused into the semiconductor substrate; The mask protrudes above the surface of the alloy layer. Master for electroforming. (Appendix 2) 10. The electroforming master according to claim 1, wherein the mask is made of an oxide film that is an oxide of a constituent element of the semiconductor substrate. (Appendix 3) 3. The electroforming master according to claim 1, wherein the alloy layer is a thermally diffused alloy layer formed by thermally diffusing a metal element into a semiconductor substrate. (Appendix 4) 4. The electroforming master according to claim 1, wherein the semiconductor substrate is a silicon substrate, the insulating layer is a silicon oxide film, and the alloy layer is composed mainly of silicon and a metal element. (Appendix 5) 5. The electroforming master according to claim 4, wherein the metal element is nickel, tantalum, or chromium. (Appendix 6) forming a resist pattern on an insulating layer of a semiconductor substrate having an insulating layer formed on a surface thereof by an insulating treatment; a step of etching the insulating layer using the resist pattern as a mask to form a mask made of the insulating layer; forming a metal layer on a surface of a semiconductor substrate with a mask; a step of heat-treating the semiconductor substrate having the metal layer to diffuse metal elements constituting the metal layer from the surface of the semiconductor substrate into the semiconductor substrate; removing the metal layer remaining on the surface of the semiconductor substrate; A method for manufacturing an electroforming master, comprising: (Appendix 7) In the step of forming a metal layer, a native oxide film formed on a surface of a semiconductor substrate is removed in a film forming apparatus for forming the metal layer before the metal layer is formed. A method for manufacturing an electroforming master according to Appendix 6. (Appendix 8) 8. The method for manufacturing an electroforming master according to claim 7, wherein in the step of forming the metal layer, the metal layer is formed using a sputtering method, and the native oxide film is removed by reverse sputtering the surface of the semiconductor substrate. (Appendix 9) 9. The method for manufacturing an electroforming master according to any one of claims 6 to 8, wherein a silicon substrate is used as the semiconductor substrate. (Appendix 10) A method for producing a metal molded product using the electroforming master according to any one of Supplementary Note 1 to Supplementary Note 5, an electroforming step in which, while the electroforming master is immersed in an electroforming solution, a current is passed through the alloy layer, causing a metal to precipitate from the electroforming solution and grow a metal layer on the surface of the alloy layer, and openings are formed at positions corresponding to the mask, thereby forming a metal molded product having openings; a peeling step of peeling the metal molded object from the surface of the alloy layer; a cleaning step of cleaning the electroforming master using sulfuric acid / hydrogen peroxide, sulfamic acid, or ferric chloride after the peeling step; This is a metal molding manufacturing method in which the above steps are repeated to manufacture multiple metal moldings using a single electroforming master. [Explanation of symbols]

[0062] 10 Nozzle plate 11 Metal layer 12 Nozzle (opening) 20 Electroforming master 21 Semiconductor substrate 21S surface 21a alloy layer Surface of the 21aS alloy layer 21bS Semiconductor surface without alloy layer 22 Insulating layer 23 Mask 25 metal layer 27 Heating device 28 Sulfuric acid and hydrogen peroxide solution 30 Resist film 31 Resist Pattern 40 Sputtering deposition equipment Ar sputter ions Etching gas T Target X main scanning direction Y sub-scanning direction

Claims

1. a semiconductor substrate; and an insulating mask provided on a portion of a surface of the semiconductor substrate; the mask is made of an insulating layer formed by insulating treatment on the surface of the semiconductor substrate; a portion of the surface of the semiconductor substrate where the mask is not provided is an alloy layer containing a constituent element of the semiconductor substrate and a metal element diffused into the semiconductor substrate; the mask protrudes from the surface of the alloy layer; Master for electroforming.

2. 2. The electroforming master according to claim 1, wherein the insulating layer is an oxide film that is an oxide of a constituent element of the semiconductor substrate, a nitride film that is a nitride of the constituent element, or an oxynitride film that is an oxynitride of the constituent element.

3. 2. The electroforming master according to claim 1, wherein the alloy layer is a thermally diffused alloy layer formed by thermally diffusing the metal element into the semiconductor substrate.

4. 4. The electroforming master according to claim 1, wherein the semiconductor substrate is a silicon substrate, the insulating layer is a silicon oxide film, and the alloy layer contains silicon and the metal element as main components.

5. 5. The electroforming master according to claim 4, wherein the metal element is nickel, tantalum, or chromium.

6. forming a resist pattern on an insulating layer of a semiconductor substrate having an insulating layer formed on a surface thereof by an insulating treatment; a step of etching the insulating layer using the resist pattern as a mask to form a mask made of the insulating layer; forming a metal layer on the surface of the semiconductor substrate provided with the mask; a step of heat-treating the semiconductor substrate provided with the metal layer to diffuse metal elements constituting the metal layer from the surface of the semiconductor substrate into the semiconductor substrate; removing the metal layer remaining on the surface of the semiconductor substrate; A method for manufacturing an electroforming master, comprising:

7. In the step of forming the metal layer, a native oxide film formed on the surface of the semiconductor substrate is removed in a film forming apparatus for forming the metal layer before the metal layer is formed. The method for manufacturing an electroforming master according to claim 6 .

8. 8. The method for manufacturing an electroforming master according to claim 7, wherein in the step of forming the metal layer, the metal layer is formed using a sputtering method, and the removal of the native oxide film is carried out by reverse sputtering the surface of the semiconductor substrate.

9. The method for manufacturing an electroforming master according to claim 6, wherein a silicon substrate is used as the semiconductor substrate.

10. A method for manufacturing a metal molded product using the electroforming master according to claim 1, an electroforming step in which, while the electroforming master is immersed in an electroforming solution, a current is passed through the alloy layer, causing a metal layer to grow on the surface of the alloy layer using metal precipitated from the electroforming solution, and openings are formed at positions corresponding to the mask, thereby forming a metal molded product having the openings; a peeling step of peeling the metal molded article from the surface of the alloy layer; a cleaning step of cleaning the electroforming master using sulfuric acid / hydrogen peroxide, sulfamic acid, or ferric chloride after the peeling step; The above steps are repeated to produce a plurality of the metal molded products using one electroforming master.

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