Method of manufacturing articles
By employing controlled potential cleaning with counter electrodes during the etching process, the method addresses the issue of pattern degradation in vapor deposition masks, ensuring high precision and accuracy for ultra-high resolution organic EL display devices.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TOPPAN HOLDINGS INC
- Filing Date
- 2022-07-15
- Publication Date
- 2026-05-15
AI Technical Summary
The challenge in manufacturing organic EL display devices is the degradation of pattern shape and dimensional accuracy due to a low rate of replacement of the etching solution by the cleaning solution, particularly when forming small aperture diameters in vapor deposition masks.
A method involving the use of a ferric chloride solution for etching, followed by a cleaning process with a cleaning solution under controlled potential conditions using counter electrodes and a voltage application device to suppress metal ionization, ensuring precise etching and cleaning of metal materials like iron, nickel, or copper.
This method reduces variations in etching rates, resulting in vapor deposition masks with excellent pattern shape and dimensional accuracy, suitable for ultra-high resolution displays.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a method for manufacturing an article.
Background Art
[0002] Among organic electroluminescence (EL) display devices capable of displaying color images, there are those that use color filters and those that use organic EL elements that emit light in red, green, and blue. In the manufacture of the latter organic EL display device, for example, organic substances that emit light in red, green, and blue are deposited on a glass substrate by vapor deposition through a vapor deposition mask (Patent Document 1).
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] An object of the present invention is to provide a technique that can make it difficult to cause a decrease in the shape or dimensional accuracy of a pattern due to a low rate of replacement of an etching solution with a cleaning solution.
Means for Solving the Problems
[0005] According to one aspect of the present invention, a resist pattern is formed on at least one surface of a plate-shaped metal material, a region exposed at the position of an opening of the resist pattern in the at least one surface is etched using a ferric chloride solution as an etching solution, and then the surfaces of the metal material and the resist pattern are washed with a cleaning solution, and the washing with the cleaning solution is performed under a condition that a potential for suppressing ionization of a metal contained in the metal material is applied. A method for manufacturing an article is provided.
[0006] According to another aspect of the present invention, a method for manufacturing an article is provided, comprising interposing the cleaning solution between a counter electrode and the metal material, and applying a voltage between them such that the potential of the metal material becomes lower than the potential of the counter electrode.
[0007] According to yet another aspect of the present invention, a method for manufacturing an article relating to the above aspect is provided, wherein the counter electrode is made of a conductive material with a standard oxidation-reduction potential higher than that of the metal material.
[0008] According to yet another aspect of the present invention, a method for manufacturing an article relating to any of the above aspects is provided, wherein the metal material is formed from at least one metal selected from the group consisting of iron, nickel, copper and alloys thereof.
[0009] According to yet another aspect of the present invention, a method for manufacturing an article relating to any of the above aspects is provided, wherein the thickness of the resist pattern is 5 μm or more, and the opening has a diameter of 40 μm or less. [Effects of the Invention]
[0010] According to the present invention, a technique is provided that makes it less likely for a decrease in the shape or dimensional accuracy of a pattern to occur due to a low rate of replacement of the etching solution by the cleaning solution. [Brief explanation of the drawing]
[0011] [Figure 1] Figure 1 is a schematic cross-sectional view showing one step in a method for manufacturing an article according to one embodiment of the present invention. [Figure 2] Figure 2 is a schematic cross-sectional view showing other steps in the method for manufacturing an article according to one embodiment of the present invention. [Figure 3] Figure 3 is a schematic cross-sectional view showing yet another step in the method for manufacturing an article according to one embodiment of the present invention. [Figure 4] Figure 4 is a scanning electron microscope image showing an example of a structure obtained by etching and subsequent cleaning. [Figure 5]Figure 5 is a scanning electron microscope image showing another example of a structure obtained by etching and subsequent cleaning. [Modes for carrying out the invention]
[0012] Embodiments of the present invention will be described below with reference to the drawings. The embodiments described below are more specific to any of the above aspects. The matters described below can be incorporated into each of the above aspects, individually or in combination.
[0013] Furthermore, the embodiments shown below illustrate configurations for realizing the technical concept of the present invention, and the technical concept of the present invention is not limited by the material, shape, and structure of the components described below. Various modifications can be made to the technical concept of the present invention within the technical scope defined by the claims described in the claims.
[0014] Elements with similar or identical functions are given the same reference numerals in the drawings referenced below, and redundant explanations are omitted. Furthermore, the drawings are schematic, and the relationships between dimensions in one direction and those in another, and the relationships between the dimensions of one component and those of other components, may differ from reality.
[0015] Figure 1 is a schematic cross-sectional view showing one step in the method for manufacturing an article according to one embodiment of the present invention. Figure 2 is a schematic cross-sectional view showing another step in the method for manufacturing an article according to one embodiment of the present invention. Figure 3 is a schematic cross-sectional view showing yet another step in the method for manufacturing an article according to one embodiment of the present invention.
[0016] The method described here is used to manufacture a vapor deposition mask as an item. This method can also be used to manufacture items other than vapor deposition masks.
[0017] In manufacturing a vapor deposition mask, first, a metal material 11 shown in FIG. 1 is prepared. The metal material 11 is in a plate shape. The metal material 11 is formed of at least one metal selected from the group consisting of, for example, iron, nickel, copper, and alloys thereof. The thickness of the metal material 11 is, for example, within the range of 15 to 200 μm.
[0018] Next, as shown in FIG. 1, a resist pattern 12 is formed on at least one surface of the metal material 11. In FIG. 1, the resist pattern 12 is formed on both surfaces of the metal material 11. The resist pattern 12 can be formed, for example, by laminating a dry film resist on the metal material 11 and then sequentially performing pattern exposure and development processes on the dry film resist.
[0019] The thickness of the resist pattern 12 is preferably 5 μm or more. When the resist pattern 12 is formed from a dry film resist, if the thickness is reduced, wrinkles are likely to occur in the lamination process, and cracks in the resist pattern 12 are likely to occur in the etching process.
[0020] The thickness of the resist pattern 12 is preferably 15 μm or less. In order to obtain a vapor deposition mask provided with through holes having a small aperture diameter, it is desirable that the resist pattern 12 has a small thickness.
[0021] Each of the resist patterns 12 has a plurality of resist openings. The resist openings provided in one resist pattern 12 are arranged corresponding to the resist openings provided in the other resist pattern 12. The center positions of the orthographic projections of each resist opening provided in one resist pattern 12 onto a plane perpendicular to the thickness direction of the metal material 11 and the resist openings provided in the other resist pattern 12 corresponding to this resist opening are equal to each other.
[0022] Here, the resist pattern 12 provided on one side of the metal material 11 has a smaller resist opening diameter compared to the resist pattern 12 provided on the other side of the metal material 11. The resist opening diameters of the resist pattern 12 provided on one side of the metal material 11 and the resist pattern 12 provided on the other side of the metal material 11 may be equal.
[0023] It is preferable that these resist openings include those with an opening diameter of 40 μm or less. If resist patterns 12 are provided on both sides of the metal material 11, one of the resist openings of the resist patterns 12 may have an opening diameter of 40 μm or less, or both of the resist openings of the resist patterns 12 may have an opening diameter of 40 μm or less. The opening diameter of these resist openings is, for example, 10 μm or more.
[0024] Next, the first etching process is performed. In the first etching process, as shown in Figure 2, the metal material 11 is etched using the resist pattern 12 as an etching mask to form recesses on the surface of the metal material 11 at the locations of the resist openings in the resist pattern 12. Here, the recesses on one side of the metal material 11 and the recesses on the other side of the metal material 11 are formed to a depth where they do not connect.
[0025] As described above, in this case, the resist pattern 12 provided on one side of the metal material 11 has a smaller aperture diameter of resist openings compared to the resist pattern 12 provided on the other side of the metal material 11. Therefore, the recesses formed on one side of the metal material 11 have a smaller aperture diameter compared to the recesses formed on the other side of the metal material 11.
[0026] In this etching process, ferric chloride solution is used as the etching solution 13. The ferric chloride solution is prepared to have a high specific gravity, for example, a specific gravity of 1.54 to 1.61 g / cm³. 3 It is preferable that the preparation be within the specified range.
[0027] Etching of the metal material 11 with the etching solution 13 is performed by bringing the etching solution 13 into contact with the metal material 11. For example, the etching solution 13 is brought into contact with the metal material 11 by spraying it towards the metal material 11 or by immersing the metal material 11 in the etching solution 13.
[0028] It is preferable to bring the metal material 11 into contact with a high-temperature etching solution 13. For example, the temperature of the etching solution 13 is preferably in the range of 55 to 80°C.
[0029] Next, the first cleaning step is performed. In the first cleaning step, as shown in Figure 3, the composite of the metal material 11, which has recesses on both sides, and the resist pattern 12 is cleaned with a cleaning solution 14. For example, water is used as the cleaning solution 14. Cleaning with the cleaning solution 14 is performed, for example, by immersing the composite in the cleaning solution 14, by spraying or discharging the cleaning solution 14 towards the composite, or by a combination of these methods.
[0030] The cleaning with the cleaning solution 14 is performed under conditions in which a potential is applied to the metal material 11 that suppresses the ionization of the metal contained therein. Here, by using a cleaning apparatus equipped with a cleaning tank, two counter electrodes 15, and a voltage application device 16, cleaning with the cleaning solution 14 is performed while applying a voltage that suppresses the ionization of the metal contained in the metal material 11 between the metal material 11 and the counter electrodes 15. The cleaning apparatus may further be equipped with a nozzle for discharging the cleaning solution 14.
[0031] Each counter electrode 15 and the metal material 11 face each other with the resist pattern 12 and cleaning solution 14 interposed between them. The counter electrodes 15 may have any shape. For example, the counter electrodes 15 may be plate-shaped or mesh-shaped. The counter electrodes 15 do not need to face the metal material 11 as long as they are in contact with the cleaning solution 14. The cleaning apparatus here includes a pair of counter electrodes 15, but the number of counter electrodes 15 included in the cleaning apparatus can be one or more.
[0032] The counter electrode 15 is preferably made of a conductive material with a higher standard oxidation-reduction potential than the metal material 11. For example, the counter electrode 15 is formed from at least one precious metal selected from the group consisting of platinum, gold, rhodium, palladium, ruthenium, and iridium.
[0033] The voltage application device 16 applies a voltage between the metal material 11 and the counter electrode 15 such that the potential of the metal material 11 is lower than the potential of the counter electrode 15. The voltage application device 16 applies a voltage between the counter electrode 15 and the metal material 11 for part of the period from the start to the end of cleaning with the cleaning solution 14, or throughout this period. By making the potential of the metal material 11 lower than the potential of the counter electrode 15, ionization of the metal contained in the metal material 11 becomes less likely.
[0034] Next, the composite of the metal material 11, which has recesses on both sides, and the resist pattern 12 is dried. Subsequently, liquid resin is applied to one side of this composite and the coating is cured. This fills the recesses on one side of the metal material 11, which have smaller opening diameters, with the cured resin.
[0035] Next, a second etching process is performed. In the second etching process, the metal material 11 is etched using the resist pattern 12 and the resin cured layer as etching masks, deepening the recesses with larger opening diameters until they connect to the recesses with smaller opening diameters. This forms through holes in the metal material 11. The second etching process can be carried out in the same manner as described above for the first etching process, except that the object to be etched is different.
[0036] Next, a second cleaning step is performed. In the second cleaning step, the composite of the metal material 11 with through holes, the resist pattern 12, and the resin cured layer is cleaned with a cleaning solution. The second cleaning step can be performed in the same manner as the first cleaning step, except that the object to be cleaned is different.
[0037] Subsequently, the resist pattern 12 and the resin curing layer are removed from the metal material 11. Furthermore, the metal material 11 is subjected to cleaning and drying. In this way, a metal material 11 with through holes is obtained as a vapor deposition mask.
[0038] When recesses or through-holes are formed by etching, if the rate of replacement of the etching solution by the cleaning solution in the subsequent cleaning process is low, the shape or dimensional accuracy of the pattern consisting of the recesses or through-holes will deteriorate. This is particularly noticeable when the opening diameter of the recesses or through-holes is small. The method described above makes it less likely for the deterioration of the pattern shape or dimensional accuracy caused by the low rate of replacement of the etching solution by the cleaning solution to occur. This will be explained below.
[0039] In the manufacturing of organic EL display devices with a resolution of approximately 100 PPI (pixels per inch) and relatively large pixel sizes, a deposition mask with a through-hole aperture diameter of approximately 85 μm was used.
[0040] However, in recent years, ultra-high resolution (UHD) displays have been required for a variety of electronic devices, such as smartphones and virtual reality (VR) devices. Consequently, vapor deposition masks are now required to have fine through-holes that can form ultra-high resolution (UHD class) patterns. For example, in the manufacture of an organic EL display device with a resolution of 350 PPI, a vapor deposition mask with through-holes of about 40 μm in diameter is required.
[0041] To obtain a deposition mask with through-holes having small aperture diameters, as described above, the resist pattern must be thin and the through-holes must have small aperture diameters. However, when forming a resist pattern from a dry film resist, reducing its thickness makes it prone to wrinkling during the lamination process and cracking during the etching process. Therefore, to obtain a deposition mask with through-holes having the aforementioned aperture diameters, the resist pattern used as an etching mask needs to have resist openings with an aperture diameter of approximately 20 μm and preferably has a thickness of 5 μm or more.
[0042] Incidentally, etching of metal materials consisting of elemental metals such as iron, nickel, and copper, or alloys thereof, is generally performed by spraying ferric chloride solution, which is an inexpensive etching solution. Ferric chloride solution is characterized by high temperature and high specific gravity; for example, a solution temperature in the range of 55 to 80°C and a specific gravity of 1.54 to 1.61 g / cm³. 3 When ferric chloride solution within a certain range is used for etching, the resulting surface becomes smooth. Through holes formed by etching, which result in a smooth surface, have high circularity in their opening shape and small in-plane variation in opening diameter. Therefore, ferric chloride solution, which is generally hot and has a high specific gravity, is used for the above etching process.
[0043] However, ferric chloride solution, with its high specific gravity, has a problem in that its high viscosity results in poor substitution with the cleaning solution during the post-etching cleaning process. This substitution problem becomes more pronounced as the diameter of the resist openings in the resist pattern decreases.
[0044] If this substitutability is poor, for example, differences will occur in the rate of etching solution replacement by the cleaning solution between resist openings in the resist pattern. Therefore, differences will occur in the degree of etching at the locations of these resist openings. As a result, the recesses formed in the metal material will have large variations in opening diameter, or the deposition mask obtained from this metal material will have large variations in the opening diameter of the through-holes.
[0045] Alternatively, if the above-mentioned substitutability is poor, regions with different rates of replacement of the etching solution by the cleaning solution will be created within one or more resist openings in the resist pattern. If regions with different replacement rates are created within a single resist opening, it will result in areas with different levels of etching progress at that location in the resist opening. As a result, the recesses formed in the metal material, or the through-holes in the deposition mask obtained from this metal material, will have low precision in the shape of the openings.
[0046] Figure 4 is a scanning electron microscope image showing an example of a structure obtained by etching and subsequent cleaning. Figure 5 is a scanning electron microscope image showing another example of a structure obtained by etching and subsequent cleaning.
[0047] The structures shown in Figures 4 and 5 were obtained by performing the first etching process described with reference to Figure 2, then performing a cleaning process similar to the first cleaning process except that the counter electrode 15 and voltage application device 16 were omitted, and then sequentially removing the resist pattern 12 from the metal material 11, cleaning the metal material 11, and drying it. Here, the thickness of the resist pattern 12 is 10 μm, and the openings of the resist are approximately square in shape.
[0048] Thus, if voltage is not applied using the counter electrode 15 and the voltage application device 16 during the cleaning process, patterns with poor shape and dimensional accuracy will occur, as well as patterns with poor shape or dimensional accuracy. Therefore, it is not possible to manufacture a vapor deposition mask with excellent pattern shape and dimensional accuracy.
[0049] In contrast, the method described with reference to Figures 1 to 3 involves applying voltage using the counter electrode 15 and the voltage application device 16 during the cleaning process. This voltage application makes it less likely for the metal contained in the metal material 11 to be ionized during the cleaning process. Therefore, variations in the degree of etching can be reduced, and consequently, it becomes possible to manufacture a vapor deposition mask with excellent pattern shape and dimensional accuracy. [Examples]
[0050] The tests conducted in connection with the present invention are described below.
[0051] (Examples) In this example, the vapor deposition mask was manufactured by the method described with reference to Figures 1 to 3.
[0052] Specifically, as the metal material 11, a long roll of metal foil supplied from a winding roll, made of low thermal expansion Invar material with a thickness of 0.025 mm, was used. Degreasing, surface finishing, and cleaning treatments were sequentially applied to both sides of this metal material 11. Next, a 10 μm thick dry film resist was laminated to both sides of the metal material 11. Then, each of the dry film resists laminated to the metal material 11 was pattern-exposed through an exposure mask. Subsequently, unexposed areas were removed from these dry film resists by developing them with a 1% sodium carbonate solution at 35°C. In this way, as shown in Figure 1, a composite was obtained consisting of the metal material 11, a resist pattern provided on one side thereof, and a resist pattern 12 provided on the other side thereof. Here, the aperture diameter of the resist openings provided in one resist pattern 12 was set to 10 μm, while the aperture diameter of the resist openings provided in the other resist pattern 12 was made larger.
[0053] Next, a first etching process was performed to form recesses on both sides of the metal material 11, as shown in Figure 2. This etching was carried out by spraying etching solution 13 from a spray nozzle onto the composite material in an etching tank. The etching solution 13 had a specific gravity of 1.525 g / cm³. 3 A ferric chloride solution was used. The temperature of etching solution 13 was set to 65°C.
[0054] Next, the first cleaning process was carried out. In the first cleaning process, the composite, in which recesses were formed on both sides of the metal material 11, was immersed in the cleaning solution 14 as shown in Figure 3, and the cleaning solution 14 was discharged from a nozzle toward the composite. Water was used as the cleaning solution 14. A platinum electrode was used as the counter electrode 15.
[0055] Next, the composite of the metal material 11, which had recesses on both sides, and the resist pattern 12 was dried. Subsequently, a liquid resin was applied to one side of this composite, and the coating film was cured. This filled the recesses on one side of the metal material 11, which had smaller opening diameters, with the cured resin.
[0056] Next, a second etching process was performed. In the second etching process, the metal material 11 was etched using the resist pattern 12 and the resin cured layer as etching masks, deepening the larger diameter recesses until they connected to the smaller diameter recesses. This formed through holes in the metal material 11. The second etching process was carried out in the same manner as the first etching process, except that the object to be etched was different.
[0057] Next, a second cleaning process was carried out. In the second cleaning process, the composite of the metal material 11 with through holes, the resist pattern 12, and the resin cured layer was cleaned with a cleaning solution. The second cleaning process was carried out in the same manner as the first cleaning process, except that the object to be cleaned was different.
[0058] Next, the resist pattern 12 and the resin curing layer were removed from the metal material 11. Specifically, a 5% sodium hydroxide solution at 50°C was sprayed onto the composite to dissolve and remove the resist pattern 12 and the resin curing layer.
[0059] Subsequently, the metal material 11 was washed and dried. In this manner, a metal material 11 with through holes was obtained as a vapor deposition mask.
[0060] Furthermore, multiple deposition masks were manufactured in the same manner as described above, except that at least one of the thickness of the resist pattern 12 and the aperture diameter of the resist opening provided in one of the resist patterns 12 was changed. Note that when pattern exposure was performed using a dry film resist with a thickness of 15 μm or 20 μm to form a resist pattern with a resist opening of 10 μm in diameter, it was not possible to form a resist opening in the dry film resist, and therefore no further etching or similar steps were performed.
[0061] (Comparative example) In this example, multiple deposition masks were manufactured in the same manner as in the above embodiment, except that the counter electrode 15 and the voltage application device 16 were omitted and voltage was not applied in the first and second cleaning steps. In this example as well, when pattern exposure was performed to form a resist pattern with a resist opening of 10 μm diameter using a dry film resist with a thickness of 15 μm or 20 μm, it was not possible to form a resist opening in the dry film resist, so subsequent etching or the like was not performed.
[0062] (evaluation) The diameter and shape of the through-holes were examined for the deposition masks in the examples and comparative examples. Masks with sufficiently small in-plane variation in the diameter and excellent shape accuracy of the diameter were evaluated as "A". Masks with slightly large in-plane variation in the diameter or slightly poor shape accuracy of the diameter were evaluated as "B". Masks with large in-plane variation in the diameter or poor shape accuracy of the diameter were evaluated as "C".
[0063] The evaluation results obtained for the deposition masks in the examples are shown in Table 1 below. The evaluation results obtained for the deposition masks in the comparative examples are shown in Table 2 below.
[0064] [Table 1]
[0065] [Table 2]
[0066] As shown in Table 1, the method of the embodiment made it possible to form through holes in the metal material 11 with sufficiently small in-plane variation in the aperture diameter and excellent shape accuracy of the aperture diameter, regardless of the thickness of the resist pattern 12 and the aperture diameter of the resist opening provided in one of the resist patterns 12.
[0067] On the other hand, in the comparative example method, as shown in Table 2, when the aperture diameter of the resist opening provided in one of the resist patterns 12 was 40 μm, regardless of the thickness of the resist pattern 12, it was possible to form a through hole in the metal material 11 with sufficiently small in-plane variation of the aperture diameter and excellent shape accuracy of the aperture diameter. However, in the comparative example method, when the aperture diameter of the resist opening provided in one of the resist patterns 12 was reduced, the in-plane variation of the aperture diameter increased or the shape accuracy of the aperture diameter decreased. Furthermore, in the comparative example method, when the aperture diameter of the resist opening provided in one of the resist patterns 12 was small, there was a tendency for the in-plane variation of the aperture diameter to increase or the shape accuracy of the aperture diameter to decrease as the thickness of the resist pattern 12 increased. [Explanation of Symbols]
[0068] 11...Metal material, 12...Resist pattern, 13...Etching solution, 14...Cleaning solution, 15...Counter electrode, 16...Voltage application device.
Claims
1. Forming a resist pattern on at least one surface of a plate-shaped metal material, Etching the region exposed at the location of the opening of the resist pattern on at least one of the aforementioned surfaces using ferric chloride solution as the etching solution, Subsequently, the surfaces of the metal material and the resist pattern are cleaned with a cleaning solution. A method for manufacturing an article, comprising the cleaning solution, wherein the cleaning is performed under conditions in which a potential that suppresses the ionization of the metal contained therein is applied to the metal material.
2. The method for manufacturing an article according to claim 1, wherein the cleaning with the cleaning solution comprises applying a voltage between the counter electrode and the metal material, with the cleaning solution interposed between them, such that the potential of the metal material becomes lower than the potential of the counter electrode.
3. The method for manufacturing an article according to claim 2, wherein the counter electrode is made of a conductive material with a standard oxidation-reduction potential higher than that of the metal material.
4. The method for manufacturing an article according to claim 1, wherein the metal material is formed from at least one metal selected from the group consisting of iron, nickel, copper, and alloys thereof.
5. The method for manufacturing an article according to claim 1, wherein the thickness of the resist pattern is 5 μm or more, and the opening has a diameter of 40 μm or less.