Shower head and method for manufacturing the shower head

Abstract

To provide a shower head having a reduced risk of cracking in a coat, and a method for producing a shower head.SOLUTION: A shower head has: a base material having one or more through holes penetrating in a thickness direction; one or more sleeves inserted into the base material so as to cover an inner peripheral surface of the through hole, the sleeves having a linear expansion coefficient smaller than that of the base material; and a coat formed over a surface of the base material and end faces of the sleeves. The one or more through holes have inner diameters smaller than outer diameters of the sleeves at a use temperature higher than a room temperature. The one or more sleeves are inserted into the through holes of the base material that has been heated to a process temperature higher than the use temperature and thermally expanded, and the base material is subsequently cooled to cause the sleeves to be fitted into the through holes.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a showerhead that can reduce the gap dimension between a plate body and a sleeve, and a method for manufacturing the showerhead. [Background technology]

[0002] A showerhead for injecting a process gas into a chamber is known (see Patent Document 1). This showerhead has a plurality of through holes formed therein for passing the process gas. The showerhead is easily corroded because it is exposed to the process gas and plasma. To prevent the showerhead from corroding, the inner circumferential surface of the through hole of the showerhead is often covered and protected by a sleeve made of a metal different from the metal constituting the showerhead body. Also, the surface of the showerhead is often covered and protected by a ceramic coating that is resistant to plasma and corrosion by the process gas. The coating is often formed so as to extend over both the showerhead body and the sleeve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-220623 A DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0004] The showerhead becomes hot during plasma processing. Meanwhile, the showerhead body and the sleeve are often made of different materials and have different linear expansion coefficients. Therefore, the showerhead and the sleeve thermally expand during high-temperature plasma processing, and a gap may occur between the showerhead and the sleeve due to the difference in their linear expansion coefficients. If a gap occurs between the showerhead and the sleeve, cracks may occur in the ceramic coating starting from the periphery of the gap. If a crack occurs in the coating, the metal of the showerhead body is exposed to the processing gas and plasma from the crack, causing corrosion in that area. Therefore, one object of the present invention is to provide a showerhead and a method for manufacturing a showerhead that reduces the possibility of cracks occurring in the coating. [Means for solving the problem]

[0005] The above problems are solved by the present invention. That is, the showerhead of the present invention (1) comprises: A substrate having one or more through holes extending therethrough in a thickness direction; one or more sleeves inserted into the base material so as to cover an inner circumferential surface of the through-hole portion, the one or more sleeves having a linear expansion coefficient smaller than a linear expansion coefficient of the base material; a coating formed across a surface of the substrate and an end surface of the sleeve; Equipped with an inner diameter of the one or more through-hole portions is smaller than an outer diameter of the sleeve at an operating temperature higher than room temperature; The one or more sleeves are inserted into the through hole portion of the substrate which has been heated to a processing temperature higher than the use temperature and thermally expanded, and then the substrate is cooled so that the sleeves are fitted into the through hole portion.

[0006] The showerhead of the present invention (2) is the showerhead according to (1), The one or more sleeves have one or more tapered surfaces on their outer circumferential surfaces, and each of the one or more tapered surfaces has a diameter that decreases in a direction approaching a tip end.

[0007] The showerhead of the present invention (3) is the showerhead according to (2), The one or more tapered surfaces include a first tapered surface provided adjacent the tip.

[0008] The showerhead of the present invention (4) is the showerhead according to (2) or (3), The one or more through hole portions have one or more expanding surfaces on their inner circumferential surfaces, and each of the one or more expanding surfaces has a diameter that increases in a direction approaching a base end opposite the tip end of the sleeve.

[0009] The showerhead of the present invention (5) is the showerhead according to (4), The one or more expansion surfaces include a first expansion surface provided on an opening edge portion of the one or more through hole portions, the opening edge portion being located at an end portion approaching the base end of the sleeve.

[0010] The showerhead of the present invention (6) is the showerhead according to any one of (2) to (5), The one or more sleeves have a first step and a tip portion that is provided on the tip side of the first step and has a smaller diameter than the first step, The one or more tapered surfaces includes a second tapered surface provided on the first step portion.

[0011] The showerhead of the present invention (7) is the showerhead according to (6), A length from a base end of the one or more sleeves opposite the tip end to the first step portion is greater than a length of the tip portion in the axial direction of the sleeve.

[0012] The showerhead of the present invention (8) is the showerhead according to (6), a length from a base end of the one or more sleeves opposite to the tip end to the first step portion is shorter than a length of the tip portion in an axial direction of the sleeve; The one or more through-hole portions have a recess formed with a diameter larger than that of the tip portion, and the recess prevents interference between the base material and the tip portion before the thermal expansion.

[0013] The showerhead of the present invention (9) is the showerhead according to any one of (6) to (8), the one or more through-hole portions each have a second step portion and a large diameter portion that is provided on a base end side of the sleeve opposite the tip end relative to the second step portion and has a larger diameter than the second step portion, The one or more flared surfaces includes a second flared surface provided in the second step.

[0014] The showerhead of the present invention (10) is the showerhead according to any one of (1) to (9), The temperature used is 100 to 250°C.

[0015] The showerhead of the present invention (11) is the showerhead according to any one of (1) to (10), The processing temperature is at least 100° C. higher than the use temperature.

[0016] The showerhead of the present invention (12) is the showerhead according to any one of (1) to (11), The inner diameter of the one or more through holes becomes equal to the outer diameter of the sleeve at a temperature higher than the usage temperature.

[0017] Further, a method for manufacturing a showerhead according to the present invention (13) includes the steps of: 1. A method for manufacturing a showerhead for use at temperatures higher than room temperature, comprising: a substrate having one or more through holes penetrating in a thickness direction and upper opening edges of the one or more through holes; one or more sleeves inserted into the substrate so as to cover inner circumferential surfaces of the one or more through holes, the one or more sleeves having a linear expansion coefficient smaller than a linear expansion coefficient of the substrate and an outer diameter larger than an inner diameter of the one or more through holes at an operating temperature higher than room temperature; and a coating formed across a surface of the substrate and an end face of the sleeve, the method comprising: placing the one or more sleeves over the one or more opening edges; heating the substrate to a processing temperature that is greater than the use temperature to cause thermal expansion; inserting the one or more sleeves into the one or more through-holes of the base material which has been heated to a processing temperature higher than the use temperature and thermally expanded; cooling the base material and fitting the sleeve into the through hole; forming a coating across a surface of the substrate and an end surface of the sleeve; Equipped with.

[0018] A method for producing a showerhead according to the present invention (14) is a method for producing a showerhead according to the present invention (13), comprising the steps of: The one or more sleeves have a tapered surface at a tip portion that abuts against the opening edge portion, the tapered surface having a diameter that becomes smaller toward the tip portion in a direction in which the sleeve is inserted, The step of placing the one or more sleeves on the one or more opening edge portions includes the step of placing the sleeves on the opening edge portions via the tapered surface.

[0019] A method for producing a showerhead according to the present invention (15) is a method for producing a showerhead according to the present invention (13) or (14), comprising the steps of: the one or more through-hole portions have an expanding surface at the opening edge portion, the diameter of which increases in a direction opposite to the direction in which the one or more sleeves are inserted, The step of placing the one or more sleeves over the one or more opening edges includes placing the sleeves on the expanding surface.

[0020] A method for producing a showerhead according to the present invention (16) is a method for producing a showerhead according to any one of (13) to (15), comprising the steps of: The step of heating the substrate to a processing temperature higher than the use temperature to thermally expand the substrate includes a step of heating the substrate with a heater abutted against a surface of the substrate opposite to the surface into which the sleeve is inserted.

[0021] A method for producing a showerhead according to the present invention (17) is a method for producing a showerhead according to the present invention (16), comprising the steps of: The process of inserting the one or more sleeves into the one or more through-hole portions of the substrate that has been heated to a processing temperature higher than the usage temperature and thermally expanded includes the process of pushing the one or more sleeves into the substrate from the side opposite to the side where the heater is in contact.

[0022] Further, a method for producing a showerhead according to the present invention (18) is a method for producing a showerhead according to any one of (13) to (15), comprising the steps of: The step of heating the substrate to a processing temperature higher than the use temperature to thermally expand the substrate includes a step of heating the substrate and the sleeve in a furnace that encloses the substrate and the sleeve; The process of inserting the one or more sleeves into the one or more through hole portions of the substrate that has been heated to a processing temperature higher than the usage temperature and thermally expanded is performed by applying a load of a weight placed on the upper side of the one or more sleeves that are placed on the upper side of the one or more opening edges, the weight having a linear expansion coefficient approximately the same as that of the substrate. Effect of the Invention

[0023] According to the present invention, it is possible to provide a showerhead and a method for manufacturing a showerhead that reduces the possibility of cracks occurring in the coating. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a cross-sectional view showing a production line including a showerhead according to an embodiment. [Diagram 2] 2 is an enlarged cross-sectional view showing a first sleeve shown in FIG. 1 and a first through-hole portion into which the first sleeve is inserted. [Diagram 3] 2 is an enlarged cross-sectional view showing a second sleeve shown in FIG. 1 and a second through-hole portion into which the second sleeve is inserted. [Figure 4] 2 is a cross-sectional view showing a step in a first manufacturing method of the showerhead shown in FIG. 1, the step of placing one or more sleeves above one or more opening edges. FIG. [Diagram 5] FIG. 2 is a cross-sectional view showing a step in the first manufacturing method of the showerhead shown in FIG. 1, the step of inserting one or more sleeves into one or more through-holes of a base material that has been heated to a processing temperature higher than the usage temperature and thermally expanded. [Figure 6] 1. FIG. 4 is a cross-sectional view showing a step in a second manufacturing method of the showerhead shown in FIG. 1, the step of placing one or more sleeves above one or more opening edges. [Figure 7] FIG. 2 is a cross-sectional view showing a step in the second manufacturing method of the showerhead shown in FIG. 1, the step of inserting one or more sleeves into one or more through-holes of a base material that has been heated to a processing temperature higher than the usage temperature and thermally expanded. [Figure 8] 11 is a cross-sectional view showing a first sleeve of a shower head according to a first modified example and a first through-hole into which the first sleeve is inserted. FIG. [Figure 9] 13 is a cross-sectional view showing a first sleeve of a shower head according to a second modified example and a first through-hole into which the first sleeve is inserted. FIG. [Figure 10] 13 is a graph showing the relationship between the outer diameter of the first sleeve and the inner diameter of the first through-hole portion, and the temperature, corresponding to Dimension 1 of Example A4. [Figure 11] 13 is a graph showing the relationship between the outer diameter of the first sleeve and the inner diameter of the first through-hole portion, and the temperature, corresponding to dimension 2 of Example A3. [Figure 12] 13 is a graph showing the relationship between the outer diameter of the second sleeve and the inner diameter of the second through-hole portion, and the temperature, corresponding to Example B3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, an embodiment of a showerhead will be described with reference to the drawings. A showerhead is mainly used in the manufacturing process of a substrate for a flat panel display, and is used to spray a gas corrosive to metals onto a workpiece to perform a plasma treatment or the like on the surface of the workpiece. [Embodiment]

[0026] A showerhead 11 according to an embodiment will be described with reference to Figures 1 to 7. As shown in Figure 1, the showerhead 11 includes a shower plate 12, a metal housing 41 to which the shower plate 12 is supported and fixed, and a high-frequency electrode to which a high-frequency current is supplied.

[0027] As shown in Figs. 1 to 3, the shower plate 12 is formed in a flat plate shape from a metal material. The shower plate 12 has a flat plate-shaped base material 13, one or more through-holes 14 formed in the base material 13 so as to penetrate the base material 13 in the thickness direction, one or more sleeves 15 inserted into the one or more through-holes 14, a coating 16 formed across the front surface (front surface, back surface) of the base material 13 and an end surface 151 of the sleeve 15, and fixing holes 21 provided at four corners so as to pass fixing devices 17 such as bolts, positioning pins 45, etc. through. The base material 13 is formed from, for example, an aluminum alloy. The base material 13 may be formed from a copper alloy or a steel material.

[0028] The one or more sleeves 15 are inserted into the base material 13 so as to cover the inner circumferential surface of the through-hole portion 14. The axial direction S of the sleeve 15 inserted into the base material 13 is along the thickness direction of the base material 13 (the direction in which the through-hole portion 14 extends). The one or more sleeves 15 may be one or more. The one or more sleeves 15 have one or more first sleeves 15A and one or more second sleeves 15B having a different shape from the one or more first sleeves 15A. The first sleeves 15A and the second sleeves 15B have a linear expansion coefficient smaller than the linear expansion coefficient of the base material 13. In FIG. 1, two first sleeves 15A and two second sleeves 15B are shown, but these numbers are examples, and the numbers of the first sleeves 15A and the second sleeves 15B are not limited to these. The shower plate 12 may have only one of the one or more first sleeves 15A and the one or more second sleeves 15B.

[0029] Each of the one or more first sleeves 15A is configured as a stepped cylindrical sleeve, and has a through hole 152 penetrating the center in the insertion direction. The diameter of the first sleeve 15A is configured as, for example, 3 to 5 mm. The first sleeve 15A may be formed of a material having better corrosion resistance against the processing gas than the base material 13, and is preferably formed of, for example, stainless steel. The first sleeve 15A may be formed of any of steel other than stainless steel, copper alloy, and ceramics. The stainless steel constituting the first sleeve 15A may be, for example, any of SUS304, SUS326, and SUS430.

[0030] As described later, one or more sleeves 15 are inserted into the base material 13 so as to cover the inner circumferential surface of one or more through-holes 14 of the base material 13. The direction D1 in which one or more sleeves 15 are inserted is downward in the plane of the paper in Figs. 2 and 3. As shown in Fig. 2, each of the one or more first sleeves 15A has an outer circumferential surface 22, a first step 23, a tip portion 24 provided on the tip side of the first step 23 in the insertion direction D1, a tip 25 provided on the tip portion 24 and provided at the tip of the insertion direction D1, a base end 26 provided on the opposite side to the tip 25 in the insertion direction D1, and one or more tapered surfaces 27 provided on the outer circumferential surface 22. The one or more tapered surfaces 27 may be one or more. The one or more tapered surfaces 27 include a first tapered surface 27A provided near the tip 25 of the outer circumferential surface 22 and a second tapered surface 27B provided on the first step 23 of the outer circumferential surface 22. The first tapered surface 27A has a smaller diameter as it approaches the tip 25 (in the insertion direction D1). The second tapered surface 27B has a smaller diameter as it approaches the tip 25 (in the insertion direction D1).

[0031] The diameter of the tip portion 24 is smaller than the diameter of the portion of the first sleeve 15A where the first step portion 23 is provided. As shown in Fig. 2, the length L1 from the base end 26 to the first step portion 23 in the axial direction S (insertion direction D1) is larger than the length L2 of the tip portion 24 in the axial direction S (insertion direction D1) of the first sleeve 15A. Therefore, in the manufacturing method described below, when the first step portion 23 of the first sleeve 15A is placed on the opening edge portion 32, the tip portion 24 does not interfere with the second step portion 33 of the first through-hole portion 14A.

[0032] As shown in FIG. 3, each of the one or more second sleeves 15B is a cylindrical sleeve having a through hole 152 penetrating the center in the insertion direction D1. The diameter of the second sleeve 15B is, for example, 3 to 5 mm. The second sleeve 15B may be made of a material having better corrosion resistance to the process gas than the base material 13, and is preferably made of, for example, ceramics. The second sleeve 15B may be made of, for example, stainless steel, steel, or copper alloy. The ceramic constituting the second sleeve 15B may be, for example, any of alumina, mullite, and aluminum nitride.

[0033] The second sleeve 15B has an outer peripheral surface 22, a tip 25 provided at the tip in the insertion direction D1, a base end 26 provided on the opposite side to the tip 25 in the insertion direction D1, and a first tapered surface 27A (tapered surface 27) provided at a position corresponding to the tip 25 of the outer peripheral surface 22.

[0034] The one or more through-holes 14 may be one or more. As shown in Fig. 1, the one or more through-holes 14 have one or more first through-holes 14A into which one or more first sleeves 15A are inserted, and one or more second through-holes 14B into which one or more second sleeves 15B are inserted and have a different shape from the first through-holes 14A.

[0035] As shown in FIG. 2, the first through hole portion 14A is configured as a circular stepped through hole portion. The first through hole portion 14A has an inner circumferential surface 31, an opening edge portion 32 on the upper side of the inner circumferential surface 31, a second step portion 33, a large diameter portion 34 provided on the base end 26 side of the sleeve 15 (opposite to the direction D1 in which the sleeve 15 is inserted) of the second step portion 33 and having a larger diameter than the second step portion, and one or more enlarged diameter surfaces 35 provided on the inner circumferential surface 31. The opening edge portion 32 is located at an end portion on the base end 26 side of the sleeve 15 (opposite direction D2 in which the sleeve 15 is inserted). The one or more enlarged diameter surfaces 35 may be one or more. The one or more enlarged diameter surfaces 35 have a first enlarged diameter surface 35A provided on the opening edge portion 32 or its vicinity, and a second enlarged diameter surface 35B provided on the second step portion 33. The diameter of the large diameter portion 34 is larger than the diameter of the second step portion 33. The first expansion surface 35A has a larger diameter toward the base end 26 of the sleeve 15 (the direction D2 opposite to the direction in which the sleeve 15 is inserted). The second expansion surface 35B has a larger diameter toward the base end 26 of the sleeve 15 (the direction D2 opposite to the direction in which the sleeve 15 is inserted).

[0036] The inner diameter of the large diameter portion 34 of the first through hole portion 14A is smaller than the outer diameter of the first step portion 23 of the first sleeve 15A at a usage temperature described later. The inner diameter of the large diameter portion 34 of the first through hole portion 14A is preferably smaller than the outer diameter of the first step portion 23 of the first sleeve 15A even at room temperature. Furthermore, the inner diameter of the large diameter portion 34 of the first through hole portion 14A becomes equal to the outer diameter of the first step portion 23 of the first sleeve 15A at a temperature higher than the usage temperature (for example, a processing temperature described later). The inner diameter of the second step portion 33 of the first through hole portion 14A is smaller than the outer diameter of the tip portion 24 of the first sleeve 15A at a usage temperature described later. The inner diameter of the second step portion 33 of the first through hole portion 14A is preferably smaller than the outer diameter of the tip portion 24 of the first sleeve 15A even at room temperature. Furthermore, the inner diameter of the second step portion 33 of the first through hole portion 14A becomes equal to the outer diameter of the tip portion 24 of the first sleeve 15A at a temperature higher than the usage temperature (for example, the processing temperature described below).

[0037] As shown in FIG. 3, the second through hole portion 14B is configured as a through hole portion having a circular shape and a substantially uniform inner diameter in the axial direction S. The second through hole portion 14B has an inner circumferential surface 31, an opening edge portion 32 on the upper side of the inner circumferential surface 31, and a first enlarged diameter surface 35A (enlarged diameter surface 35) provided on the opening edge portion 32. The first enlarged diameter surface 35A has a diameter that increases toward the direction D2 opposite to the direction in which the sleeve 15 is inserted. The inner diameter of the second through hole portion 14B is smaller than the outer diameter of the second sleeve 15B at a usage temperature described later. The inner diameter of the second through hole portion 14B is preferably smaller than the outer diameter of the second sleeve 15B even at room temperature. Furthermore, the inner diameter of the second through hole portion 14B becomes equal to the outer diameter of the second sleeve 15B at a temperature higher than the usage temperature (for example, a processing temperature described later).

[0038] The coating 16 is made of ceramics such as alumina (Al2O3) and is formed by applying (spraying) molten ceramics such as alumina (Al2O3) to the surface of the base material 13 and the end face 151 of the sleeve 15.

[0039] With reference to FIG. 1, a method of using the shower head 11 will be described. The shower plate 12 of the shower head 11 is fixed to the housing 41 via fasteners 17 such as bolts and nuts. As a result, the shower plate 12 is suspended from above. A workpiece W consisting of a substrate or the like is sent to the shower head 11 on a transfer path 42 located below the shower head 11. Cl2 gas and the like are supplied to the inside of the housing 41. The space below the shower plate 12 is covered with, for example, a chamber 43, and the workpiece W is sent inside the chamber 43 in the sending direction indicated by the arrow. A high-frequency current is applied to the high-frequency electrode from a power source (not shown) to generate a loop current in the shower plate 12. This forms an induction electric field in the chamber 43. The Cl2 gas supplied from the shower head 11 is turned into plasma, and plasma is generated in the space below the shower head 11 in the chamber 43. This causes the workpiece W to be subjected to plasma processing. The temperature (operating temperature) of the shower head 11 during plasma processing becomes high, approximately 100 to 250°C.

[0040] Next, a first manufacturing method for the showerhead 11 of this embodiment will be described with reference to FIGS.

[0041] As shown in FIG. 4, the shower plate 12 is sandwiched between fixing plates 44 from above and below. The plates 44 are fixed to the shower plate 12 by positioning pins 45 for fixing that are passed through the fixing holes 21 of the shower plate 12. The upper first plate 44A is formed in a rectangular flat plate shape. The first plate 44A is preferably formed of the same material as the base material 13 of the shower plate 12 so as to have the same linear expansion coefficient as the linear expansion coefficient of the base material 13 of the shower plate 12. The upper first plate 44A has one or more through holes 46 provided at positions corresponding to one or more through hole portions 14 of the shower plate 12, and second fixing holes 28 provided at positions corresponding to four corners and through which the positioning pins 45 are passed.

[0042] The lower second plate 44B is formed in a rectangular flat plate shape. The second plate 44B is preferably formed of the same material as the base material 13 of the shower plate 12 so as to have the same linear expansion coefficient as the linear expansion coefficient of the base material 13 of the shower plate 12. The lower second plate 44B has second fixing holes 28 provided at positions corresponding to the four corners and through which the positioning pins 45 are passed.

[0043] First plate 44A is positioned and fixed to shower plate 12 by positioning pins 45 passed through first fixing holes 21. Second plate 44B is positioned and fixed to shower plate 12 by positioning pins 45 passed through second fixing holes 21. In this way, shower plate 12 forms unit 47 sandwiched between first plate 44A and second plate 44B from above and below.

[0044] In the first step of the present manufacturing method, one or more sleeves 15 are placed on the unit 47. That is, one or more first sleeves 15A are placed on one or more first through-hole portions 14A via one or more through-holes 46, and one or more second sleeves 15B are placed on one or more second through-hole portions 14B via one or more through-holes 46. Each of the one or more first sleeves 15A is placed on the first enlarged diameter surface 35A, which is the opening edge portion 32 of the first through-hole portion 14A, via the second tapered surface 27B of the first step portion 23 (see FIG. 2). Therefore, the first sleeve 15A is stably supported by the base material 13 while remaining in an upright position. Furthermore, the first sleeve 15A is also maintained in its upright position by the through-hole 46 of the first plate 44A. In addition, since the second tapered surface 27B and the first enlarged diameter surface 35A are provided, the insertion of the first sleeve 15A, which will be described below, is performed smoothly. Furthermore, since the second diameter expansion surface 35B is provided, the tip portion 24 can be smoothly inserted into the second step portion 33, which will be described next.

[0045] Each of the one or more second sleeves 15B is placed on the first enlarged diameter surface 35A, which is the opening edge 32 of the second through-hole portion 14B, via the first tapered surface 27A located at the tip in the insertion direction D1 (see FIG. 3). Therefore, the second sleeve 15B is stably supported by the base material 13 while remaining in an upright position. Furthermore, the second sleeve 15B is also maintained in its upright position by the through hole 46 of the first plate 44A. Furthermore, the first tapered surface 27A and the first enlarged diameter surface 35A facilitate smooth insertion of the second sleeve 15B, which will be described below.

[0046] At room temperature, the inner diameter of the first through hole portion 14A (the inner diameter of the second step portion 33 and the inner diameter of the large diameter portion 34) is set smaller than the outer diameter of the first sleeve 15A (the outer diameter of the tip portion 24 and the outer diameter of the first step portion 23). Similarly, at room temperature, the inner diameter of the second through hole portion 14B is set smaller than the outer diameter of the second sleeve 15B.

[0047] In the second step of the present manufacturing method, the worker places the unit 47 with the first sleeve 15A and the second sleeve 15B placed on the upper side on a flat heater 48, and heats the unit 47 to a processing temperature higher than the usage temperature (approximately 100 to 250°C). At this time, the heater 48 is abutted against the surface of the base material 13 opposite to the surface into which the sleeve 15 is inserted. The heater 48 heats the base material 13 to cause thermal expansion. In the third step of the present manufacturing method, a step is performed in which one or more sleeves 15 are inserted in the insertion direction D1 into one or more through-hole portions 14 that have thermally expanded due to the thermal expansion of the base material 13. The processing temperature may be 350 to 450°C, preferably 370 to 430°C, and more preferably 380 to 420°C. Since the processing temperature is a high temperature that is 100°C or more higher than the usage temperature (approximately 100 to 250°C) during plasma treatment, the base material 13 is thermally expanded sufficiently. In this process, the diameter of the first through hole portion 14A becomes larger, causing the first sleeve 15A to fall under its own weight in the D1 direction relative to the first through hole portion 14A, and the diameter of the second through hole portion 14B becomes larger, causing the second sleeve 15B to fall under its own weight in the D1 direction relative to the second through hole portion 14B.

[0048] Alternatively, if the diameter of the first sleeve 15A is close to the diameter of the first through-hole portion 14A after thermal expansion, and the diameter of the second sleeve 15B is close to the diameter of the second through-hole portion 14B after thermal expansion, the first sleeve 15A and the second sleeve 15B do not fall by their own weight. In this case, in this process, the worker uses a small hammer or the like to push the first sleeve 15A and the second sleeve 15B from above in the D1 direction, or uses a small hammer or the like to hit the first sleeve 15A and the second sleeve 15B from above and insert them in the D1 direction. Therefore, the side where the small hammer or the like is brought into contact with the first sleeve 15A and the second sleeve 15B is opposite the side where the heater 48 is abutted.

[0049] In the case of heating the unit 47 by placing the unit 47 on the flat heater 48 as in this embodiment, since there is an open space above the unit 47, the open space can be used to access the unit 47 from above in this process. Also, since the heater 48 abuts against the lower side of the unit 47, the base material 13 of the shower plate 12 can be heated in a concentrated manner, and the base material 13 can be actively thermally expanded.

[0050] In contrast, the first sleeve 15A abuts against the first enlarged diameter surface 35A of the opening edge portion 32 at the second tapered surface 27B of the first step portion 23, and is supported on the base material 13 with a minimum area. This prevents the heat conducted to the base material 13 from being efficiently conducted to the first sleeve 15A. This makes it difficult to cause a situation in which the first sleeve 15A is thermally expanded by the heat from the heater 48, making it difficult to insert the first sleeve 15A into the first through-hole portion 14A.

[0051] Similarly, the second sleeve 15B abuts against the first enlarged diameter surface 35A of the opening edge portion 32 at the first tapered surface 27A of the tip 25, and is supported on the base material 13 with a minimum area. This prevents the heat conducted to the base material 13 from being efficiently conducted to the second sleeve 15B. This makes it difficult to cause a situation in which the second sleeve 15B is thermally expanded by the heat from the heater 48, making it difficult to insert the second sleeve 15B into the second through-hole portion 14B.

[0052] In this embodiment, a first tapered surface 27A is formed at the tip 26, and a second enlarged diameter surface is formed at the second step 33 that receives the tip portion 24 of the first sleeve 15A. Therefore, the tip portion 24 is accurately positioned with respect to the second step 33 (small diameter portion), and when the first sleeve 15A is inserted into the first through-hole portion 14A, the tip portion 24 is smoothly inserted into the second step 33 (small diameter portion), effectively preventing the tip portion 24 from bending or breaking.

[0053] In the fourth step of this manufacturing method, the worker moves unit 47, in which first sleeve 15A and second sleeve 15B are inserted, from above heater 48 relative to base material 13, and cools base material 13 to room temperature. This returns base material 13 to the state before thermal expansion, and first sleeve 15A is fitted into first through-hole portion 14A, and second sleeve 15B is fitted into second through-hole portion 14B. This makes it possible to eliminate any gap between first sleeve 15A and first through-hole portion 14A, and to eliminate any gap between second sleeve 15B and second through-hole portion 14B, at room temperature and the operating temperature.

[0054] In the fifth step of this manufacturing method, ceramics such as alumina (Al2O3) are sprayed onto the surface of substrate 13 that has been cooled to room temperature. This forms ceramic coating 16 across the surface of substrate 13 and end face 151 of sleeve 15 (first sleeve 15A, second sleeve 15B). This completes shower plate 12. By assembling this shower plate 12 into housing 41, showerhead 11 is completed.

[0055] Next, a second manufacturing method for the showerhead 11 of this embodiment will be described with reference to FIGS.

[0056] 6, as in the first manufacturing method, the shower plate 12 is sandwiched between fixing plates 44 from above and below. The configurations of the upper first plate 44A and the lower second plate 44B are the same as in the first manufacturing method. The shower plate 12 forms a unit 47 sandwiched between the upper and lower first plates 44A and 44B.

[0057] In the first step of the present manufacturing method, one or more sleeves 15 are placed on the unit 47. That is, one or more first sleeves 15A are placed on one or more first through-hole portions 14A via one or more through-holes 46, and one or more second sleeves 15B are placed on one or more second through-hole portions 14B via one or more through-holes 46. Each of the one or more first sleeves 15A is placed on the first enlarged diameter surface 35A, which is the opening edge portion 32 of the first through-hole portion 14A, via the second tapered surface 27B of the first step portion 23 (see FIG. 2). Therefore, the first sleeve 15A is stably supported by the base material 13 while remaining in an upright position. Furthermore, the first sleeve 15A is also held in its upright position by the through-holes 46 of the first plate 44A.

[0058] Each of the one or more second sleeves 15B is placed on the first enlarged diameter surface 35A, which is the opening edge portion 32 of the second through-hole portion 14B, via the first tapered surface 27A (see FIG. 3). Therefore, the second sleeves 15B are stably supported in an upright position by the base material 13. Furthermore, the second sleeves 15B are maintained in an upright position by the through holes 46 of the first plate 44A.

[0059] At room temperature, the inner diameter of first through hole portion 14A (the inner diameter of second step portion 33, the inner diameter of large diameter portion 34) is set to be equal to or smaller than the outer diameter of first sleeve 15A (the outer diameter of tip portion 24, the outer diameter of first step portion 23). Similarly, at room temperature, the inner diameter of second through hole portion 14B is set to be equal to or smaller than the outer diameter of second sleeve 15B.

[0060] In the second step of the present manufacturing method, the worker places the unit 47 with the first sleeve 15A and the second sleeve 15B placed on the upper side in a furnace 51 (electric furnace) and heats the unit 47 to a processing temperature higher than the usage temperature (about 250°C). At that time, the first weight 52 is placed on the upper side of the first sleeve 15A, and the second weight 53 is placed on the upper side of the second sleeve 15B. The first weight 52 and the second weight 53 are made of a plate material made of the same material (aluminum alloy) as the base material 13 so as to have the same linear expansion coefficient as the base material 13. The first weight 52 has one or more first protrusions 52A that can be abutted against the tops of one or more first sleeves 15A and inserted into one or more through holes 46 of the first plate 44A. The second weight 53 has one or more second protrusions 53A that abut against the tops of the one or more second sleeves 15B and can be inserted into the one or more through holes 46 of the first plate 44A.

[0061] In the third step of the present manufacturing method, the unit 47 is heated to a processing temperature in a furnace 51, and one or more sleeves 15 are inserted into one or more through-holes 14 in the insertion direction D1. The processing temperature may be 350 to 450°C, preferably 370 to 430°C, and more preferably 380 to 420°C. The processing temperature is 100°C or higher than the operating temperature of the shower head 11 (approximately 100 to 250°C), so that the base material 13 is thermally expanded sufficiently. In this step, the diameter of the first through-hole 14A increases, and the first sleeve 15A falls into the first through-hole 14A due to the weight of the first weight 52. In addition, the diameter of the second through-hole 14B increases, and the second sleeve 15B falls into the second through-hole 14B due to the weight of the second weight 53.

[0062] In the second manufacturing method, since it is often difficult for an operator to access the unit 47 in the furnace 51 with a hammer or the like, the first sleeve 15A and the second sleeve 15B are inserted into the base material 13 in the D1 direction by the weights of the first weight 52 and the second weight 53. In addition, since the linear expansion coefficients of the first weight 52 and the second weight 53 are set to be the same as the linear expansion coefficient of the base material 13, even if the first weight 52 and the second weight 53 thermally expand in the furnace 51, the axial direction of the first sleeve 15A and the second sleeve 15B will not deviate from the axial direction of the through-hole portion 14. This prevents the sleeve 15 from being properly inserted into the through-hole portion 14.

[0063] In this embodiment, a first tapered surface 27A is formed at the tip 26, and a second enlarged diameter surface is formed at the second step 33 that receives the tip portion 24 of the first sleeve 15A. Therefore, when the first sleeve 15A is inserted into the first through-hole portion 14A, the tip portion 24 is smoothly inserted into the second step 33 (small diameter portion), and the tip portion 24 is effectively prevented from bending or being damaged.

[0064] In the fourth step of this manufacturing method, the worker removes the unit 47 in which the first sleeve 15A and the second sleeve 15B are inserted into the base material 13 from the furnace 51, and cools the base material 13 to room temperature. This returns the base material 13 to the state before thermal expansion, and the first sleeve 15A is fitted into the first through-hole portion 14A, and the second sleeve 15B is fitted into the second through-hole portion 14B. This makes it possible to eliminate any gap between the first sleeve 15A and the first through-hole portion 14A, and also to eliminate any gap between the second sleeve 15B and the second through-hole portion 14B, at room temperature and the operating temperature.

[0065] In the fifth step of this manufacturing method, ceramics such as alumina (Al2O3) are sprayed onto the surface of substrate 13 that has been cooled to room temperature. This forms ceramic coating 16 across the surface of substrate 13 and end face 151 of sleeve 15 (first sleeve, second sleeve). This completes shower plate 12. By assembling this shower plate 12 into housing 41, showerhead 11 is completed.

[0066] Next, the operation of the showerhead 11 manufactured by the first and second manufacturing methods will be described. The showerhead 11 is heated to an operating temperature of about 100 to 250° C. by plasma processing in the manufacturing process of substrates for flat panel displays and the like. This operating temperature is preferably about 150 to 250° C., and more preferably about 200 to 250° C. The showerhead 11 manufactured by the first and second manufacturing methods does not have a gap between the sleeve 15 and the through-hole portion 14 at room temperature.

[0067] At room temperature, the inner diameter of the through hole portion 14 of the base material 13 before the sleeve 15 is fitted is set to be slightly smaller than the outer diameter of the sleeve 15 in terms of calculation. Furthermore, even at the operating temperature, the inner diameter of the through hole portion 14 of the base material 13 before the sleeve 15 is fitted is adjusted to be slightly smaller than the outer diameter of the sleeve 15 in terms of calculation. For this reason, the base material 13 with the sleeve 15 fitted in the through hole portion 14 is considered to be in an elastically deformed state at room temperature and at the operating temperature, and not in a plastically deformed state. Then, when the temperature rises from room temperature, the base material 13 and the sleeve 15 each undergo thermal expansion. At that time, the expansion coefficients of the base material 13 and the sleeve 15 differ due to the difference in the linear expansion coefficient between the base material 13 and the sleeve 15 (i.e., the base material 13 made of an aluminum alloy undergoes greater thermal expansion than the first sleeve 15A made of stainless steel and the second sleeve 15B made of ceramics such as alumina). Therefore, as the temperature rises, the inner diameter of the through hole portion 14 of the base material 13 tends to become larger than the outer diameter of the sleeve 15. For this reason, at temperatures higher than the operating temperature, the dimensional relationship is such that a gap is generated between the through hole portion 14 of the base material 13 and the sleeve 15, in terms of calculations.

[0068] However, within a range from room temperature to the usage temperature, the amount of elastic deformation of the substrate 13 is smaller than the amount of elastic deformation at room temperature, but the substrate 13 can maintain the elastically deformed state. That is, as described above, the calculated dimensional relationship is inner diameter of the through hole portion 14 < outer diameter of the sleeve 15. In practice, the dimensional relationship within a range from room temperature to the usage temperature is inner diameter of the through hole portion 14 = outer diameter of the sleeve 15. At this time, the stress value of the elastically deformed sleeve 15 is equal to the stress value of the elastically deformed substrate 13.

[0069] The difference between the calculated outer diameter dimension of the sleeve 15 and the calculated inner diameter dimension of the through-hole portion 14 is absorbed by the elastic deformation of the base material 13 and the elastic deformation of the sleeve 15. The actual inner diameter of the through-hole portion 14 in the range from room temperature to the use temperature is a value between the calculated inner diameter of the through-hole portion 14 in the same temperature range and the calculated outer diameter of the sleeve 15 in the same temperature range. The actual inner diameter of the through-hole portion 14 in the range from room temperature to the use temperature is determined by the relationship between the difficulty of elastic deformation of the base material 13 and the difficulty of elastic deformation of the sleeve 15. More specifically, the actual inner diameter of the through-hole portion 14 in the range from room temperature to the use temperature is determined by the ratio of the reciprocal of the Young's modulus of the base material 13 to the reciprocal of the Young's modulus of the sleeve 15. The above-mentioned elastic deformation of the base material 13 and the elastic deformation of the sleeve 15 maintain a state in which there is no gap between the through-hole portion 14 and the sleeve 15 in the range from room temperature to the use temperature. Therefore, within this temperature range, the occurrence of cracks in the coating 16 due to these gaps is prevented.

[0070] In this embodiment, the main surface of the inner circumferential surface 31 of the through hole portion 14 is the surface extending in the thickness direction of the base material 13, and this surface accounts for, for example, 90 to 99% of the total area of ​​the inner circumferential surface 31. The remaining 1 to 10% is the proportion of the inner circumferential surface 31 that is accounted for by one or more expansion surfaces 35. The surface of the inner circumferential surface 31 that extends in the thickness direction of the base material 13 is the main surface that exerts the holding force and friction force to prevent the sleeve 15 from coming off.

[0071] Furthermore, the relationship between the "use temperature," the "processing temperature," and the "temperature at which the inner diameter of the through hole portion becomes equal to the outer diameter of the sleeve" described later in the examples is preferably as follows. "The temperature at which the inner diameter of the through hole is inverted into the outer diameter of the sleeve" minus "the use temperature" is 0°C to 150°C, preferably 50°C to 100°C. Moreover, "the processing temperature" minus "the temperature at which the inner diameter of the through hole is inverted into the outer diameter of the sleeve" is 0°C to 150°C, preferably 100°C to 150°C. By selecting the linear expansion coefficients of the substrate and the sleeve and the processing temperature so that "the temperature at which the inner diameter of the through hole portion reverses to the outer diameter of the sleeve" minus "the usage temperature" is 0°C to 150°C, preferably 50°C to 100°C, and "the processing temperature" minus "the temperature at which the inner diameter of the through hole portion reverses to the outer diameter of the sleeve" is 0°C to 150°C, preferably 100°C to 150°C, it is possible to prevent a gap from occurring between the through hole portion 14 and the sleeve 15 at the usage temperature and to prevent cracks from occurring in the coating 16.

[0072] According to the first embodiment, the following can be said: The shower head 11 includes a substrate 13 having one or more through-holes 14 penetrating in the thickness direction, one or more sleeves 15 inserted into the substrate 13 so as to cover the inner circumferential surface 31 of the through-holes 14, the one or more sleeves 15 having a linear expansion coefficient smaller than that of the substrate 13, and a coating 16 formed across the surface of the substrate 13 and an end surface 151 of the sleeve 15, the inner diameter of the one or more through-holes 14 being set to be equal to or smaller than the outer diameter of the sleeve 15 at room temperature and at a usage temperature higher than room temperature, the one or more sleeves 15 being inserted into the through-holes 14 of the substrate 13 that has been heated to a processing temperature higher than the usage temperature and thermally expanded, and then the substrate 13 is cooled to be fitted into the through-holes 14.

[0073] The method for manufacturing the showerhead includes manufacturing a substrate 13 having one or more through-holes 14 penetrating in a thickness direction and an upper opening edge 32 of the one or more through-holes 14, one or more sleeves 15 inserted into the substrate 13 so as to cover inner peripheral surfaces 31 of the one or more through-holes 14, the one or more sleeves 15 having a linear expansion coefficient smaller than that of the substrate 13 and an outer diameter equal to or larger than the inner diameter of the one or more through-holes 14 at room temperature and at a temperature used at or above room temperature, and a substrate 13 formed across a surface of the substrate 13 and an end surface 151 of the sleeve 15. a coating 16 formed on an end surface of the substrate 13 and used at the operating temperature, the method comprising the steps of placing one or more sleeves 15 on one or more opening edges 32; heating the substrate 13 to a processing temperature higher than the operating temperature to thermally expand the substrate 13; inserting the one or more sleeves 15 into one or more through-holes 14 of the substrate 13 that has been heated to a processing temperature higher than the operating temperature and thermally expanded; cooling the substrate 13 to fit the sleeves 15 into the through-holes 14; and forming the coating 16 across a surface of the substrate 13 and an end surface 151 of the sleeves 15.

[0074] The inventors have found that when the showerhead 11 is heated to a temperature higher than room temperature, a crack occurs in the coating 16 at a position corresponding to the gap between the inner circumferential surface 31 of the through-hole portion 14 of the substrate 13 and the outer circumferential surface 22 of the sleeve 15. This is believed to be caused by the substrate 13 and the sleeve 15 expanding when the showerhead 11 is heated to a temperature higher than room temperature, causing tensile or compressive stress concentration in the coating 16 at a position corresponding to the gap. According to the showerhead 11 and the manufacturing method thereof described above, the sleeve 15 is fitted into the through-hole portion 14 in a state in which the substrate 13 is thermally expanded, so that the gap between the inner circumferential surface 31 of the through-hole portion 14 of the substrate 13 and the outer circumferential surface 22 of the sleeve 15 can be eliminated at room temperature. It is believed that the substrate 13 holds the sleeve 15 in an elastically deformed state at room temperature. On the other hand, since the operating temperature is lower than the processing temperature, there is almost no gap between the inner circumferential surface 31 of the through hole portion 14 and the outer circumferential surface 22 of the sleeve 15 at the operating temperature. This is because, at the operating temperature or a higher temperature, due to the difference in the linear expansion coefficient between the base material 13 and the sleeve 15, the base material 13 and the sleeve 15 thermally expand so as to generate a gap between them in theory, but since the elastic deformation state of the base material 13 is maintained even at the operating temperature, no gap is generated between the base material 13 and the sleeve 15. Therefore, no gap is generated as a starting point of the crack, and no cracks are generated in the coating 16 of the shower head 11. This makes it possible to effectively prevent corrosion of the base material 13 of the shower head 11.

[0075] The one or more sleeves 15 have one or more tapered surfaces 27 on the outer circumferential surface 22, and the diameter of each of the one or more tapered surfaces 27 decreases in the direction approaching the tip 25 (insertion direction D1). This configuration makes it possible to easily insert the sleeve 15 into the through-hole portion 14.

[0076] The one or more tapered surfaces 27 include a first tapered surface 27A provided near the tip 25 (in the direction D1 in which the one or more sleeves 15 are inserted). With this configuration, when placing the one or more sleeves 15 on the opening edge 32 of the one or more through-hole portions 14 prior to insertion of the one or more sleeves 15, the sleeves 15 can be placed on the opening edge portion 32 via the first tapered surface 27A. This stabilizes the posture of the one or more sleeves 15 placed on the opening edge portion 32, facilitating the operation of simultaneously inserting the multiple sleeves 15 into the multiple through-hole portions 14.

[0077] The one or more through-hole portions 14 have one or more expanding surfaces 35 on the inner circumferential surface 31, and the diameter of each of the one or more expanding surfaces 35 increases in a direction approaching the base end 26 opposite the tip 25 of the sleeve 15 (the direction D2 opposite to the direction in which the sleeve 15 is inserted). This configuration makes it possible to easily insert the sleeve 15 into the through-hole portion 14.

[0078] The one or more expansion surfaces 35 include a first expansion surface 35A provided on the opening edge portion 32 of the one or more through hole portions 14, the opening edge portion 32 being located at the end portion approaching the base end 26 of the sleeve 15 (the direction D2 opposite to the direction in which the sleeve 15 is inserted).

[0079] According to this configuration, when placing the sleeve 15 on the opening edge portion 32 of the through-hole portion 14 prior to insertion of the sleeve 15, the sleeve 15 can be placed on the first enlarged diameter surface 35A. This stabilizes the posture of one or more sleeves 15 placed on the first enlarged diameter surface 35A, and the task of simultaneously inserting multiple sleeves 15 into multiple through-hole portions 14 can be easily performed.

[0080] The one or more sleeves 15 have a first step 23 and a tip portion 24 that is located closer to the tip 25 (in the insertion direction D1) than the first step 23 and has a smaller diameter than the first step 23, and the one or more tapered surfaces 27 include a second tapered surface 27B provided on the first step 23.

[0081] In the case where the sleeve 15 has a stepped structure having a step portion, the sleeve 15 is placed on the opening edge portion 32 of the through-hole portion 14 via the step portion. According to this configuration, even if the sleeve 15 has a stepped structure, when placing the sleeve 15 on the opening edge portion 32 of the through-hole portion 14 prior to insertion of the sleeve 15, the sleeve 15 can be placed on the opening edge portion 32 via the second tapered surface 27B of the first step portion 23. This stabilizes the posture of one or more sleeves 15 placed on the opening edge portion 32, and the work of simultaneously inserting multiple sleeves 15 into multiple through-hole portions 14 can be easily performed. In addition, the positioning and insertion of the tip portion 24 relative to the through-hole portion 14 can be easily performed.

[0082] A length L1 from a base end 26 on the opposite side to a tip 25 (in the insertion direction D1) of one or more sleeves 15 to a first step is greater than a length L2 of a tip portion 24 in the axial direction S of the sleeve (insertion direction D1). With this configuration, when the sleeve 15 is placed on the opening edge portion 32 of the through-hole portion 14 prior to insertion of the sleeve 15, it is possible to prevent the tip portion 24 of the sleeve 15 from interfering with a structural portion that receives the first step portion 23 of the through-hole portion 14 of the base material 13.

[0083] The one or more through hole portions 14 have a second step portion 33 and a large diameter portion 34 that is provided on the base end 26 side (opposite the insertion direction D1) opposite the tip 25 from the second step portion 33 and has a larger diameter than the second step portion 33, and the one or more expanded diameter surfaces 35 include a second expanded diameter surface 35B provided on the second step portion 33.

[0084] According to this configuration, when one or more sleeves 15 are inserted into one or more through-hole portions 14, the tip portion 24 can be smoothly guided to the inside of the second step portion 33. This makes it possible to minimize the occurrence of crushing of the tip portion 24 when one or more sleeves 15 are inserted into one or more through-hole portions 14.

[0085] The processing temperature is 100° C. or more higher than the usage temperature. With this configuration, the substrate 13 into which the sleeve 15 is fitted can be put into an elastically deformed state at room temperature, and by releasing this elastically deformed state at the usage temperature, it is possible to prevent a gap from being generated between the substrate 13 and the sleeve 15 at the usage temperature. This makes it possible to prevent cracks from being generated in the coating 16 due to the gap.

[0086] In the method of manufacturing a showerhead, one or more sleeves 15 have a tapered surface 27 at the tip that abuts against the opening edge 32, the diameter of which decreases toward the tip in the direction in which the sleeve 15 is inserted, and the step of placing one or more sleeves 15 on the upper side of the one or more opening edges 32 includes the step of placing the sleeve 15 on the opening edge 32 via the tapered surface 27.

[0087] According to this configuration, when placing the sleeve 15 on the opening edge 32 of the through-hole portion 14 prior to insertion of the sleeve 15, the sleeve 15 can be placed on the opening edge portion 32 via the first tapered surface 27A. This stabilizes the posture of the sleeve 15 when the base material 13 is heated, and the task of simultaneously inserting a plurality of sleeves 15 into a plurality of through-hole portions 14 can be easily performed.

[0088] In the method of manufacturing a showerhead, the one or more through-hole portions 14 have an expanding surface 35 whose diameter increases in the direction D2 opposite to the direction in which the one or more sleeves 15 are inserted into the opening edge portion 32, and the step of placing the one or more sleeves 15 on the upper side of the one or more opening edge portions 32 includes the step of placing the sleeve 15 on the expanding surface 35.

[0089] According to this configuration, when placing the sleeve 15 on the opening edge portion 32 of the through-hole portion 14 prior to insertion of the sleeve 15, the sleeve 15 can be placed on the first enlarged diameter surface 35A. This stabilizes the posture of the sleeve 15 when the base material 13 is heated, and the task of simultaneously inserting multiple sleeves 15 into multiple through-hole portions 14 can be easily performed.

[0090] In the method of manufacturing a showerhead, the step of heating the substrate 13 to a processing temperature higher than the usage temperature to thermally expand the substrate 13 includes a step of heating the substrate 13 with a heater 48 in contact with the surface of the substrate 13 opposite the surface into which the sleeve 15 is inserted.

[0091] According to this configuration, it is possible to heat the base material 13 in a concentrated manner to thermally expand the base material 13, and to minimize the application of heat to the sleeve 15. This minimizes the occurrence of a problem in which the sleeve 15 becomes difficult to fit into the through-hole portion 14 due to the heat being conducted from the heater 48 to the sleeve 15 and the thermal expansion of the sleeve 15.

[0092] In the method for manufacturing a showerhead, the step of inserting one or more sleeves 15 into one or more through-hole portions 14 of a substrate 13 that has been heated to a processing temperature higher than the usage temperature and thermally expanded includes the step of pushing in one or more sleeves 15 from the side of the substrate 13 opposite to the side against which the heater 48 abuts.

[0093] According to this configuration, the side of the substrate 13 opposite to the side where the heater 48 contacts is open, so that the sleeve 15 can be smoothly pressed into the substrate 13 by utilizing this open space.

[0094] In the method of manufacturing a showerhead, the step of heating the base material 13 to a processing temperature higher than the usage temperature to thermally expand it includes a step of heating in a furnace 51 that covers the base material 13 and the sleeve 15, and the step of inserting one or more sleeves 15 into one or more through-hole portions 14 of the base material 13 that has been heated to a processing temperature higher than the usage temperature and thermally expanded is performed by applying a load from a weight placed on the upper side of the one or more sleeves 15 placed on the upper side of the one or more opening edges 32, the weight having approximately the same linear expansion coefficient as the base material 13.

[0095] According to this configuration, since the base material 13 and the sleeves 15 are heated in the furnace 51 which is difficult to access from the surroundings, the step of inserting one or more sleeves 15 into one or more through-holes 14 is performed by the load of the weight. According to the above configuration, the weight is thermally expanded to the same extent as the base material 13 in the furnace 51. Therefore, it is possible to prevent a problem that the sleeves 15 cannot be properly inserted into the base material 13 due to the difference in thermal expansion coefficient between the base material 13 and the weight being tilted in the installation direction of the one or more sleeves 15 placed on the upper side of the opening edge portion 32.

[0096] Next, modified examples of the shower head 11 of the embodiment will be described. In the following modified examples, differences from the above embodiment will be mainly described, and illustrations or descriptions of parts common to the above embodiment will be omitted. (Modification) Referring to FIG. 8, a shower head 11 of a first modified example will be described.

[0097] Each of the one or more first sleeves 15A is configured as a stepped cylindrical sleeve, and has a through hole 152 penetrating the center in the insertion direction D1. The length from the base end 26 to the first step 23 in the axial direction S of the first sleeve 15A (the direction in which the first sleeve 15A is inserted) is shorter than the length of the tip portion 24 in the axial direction S of the sleeve 15A (the direction in which the first sleeve 15A is inserted). For this reason, in this modification, the tip of the tip portion 24 is located lower than the second step 33 of the first through hole portion 14A.

[0098] The first through-hole portion 14A into which the first sleeve 15A is inserted has a clearance portion 61 formed by cutting out a cylindrical shape at a position corresponding to the second step portion 33 so as to avoid the tip portion 24. The clearance portion 61 is formed in a cylindrical shape concentric with the main body 14AA of the first through-hole portion 14A. The inner diameter of the clearance portion 61 is formed slightly larger than the diameter of the tip portion 24 of the first sleeve 15A. The clearance portion 61 is formed in a shape (cylindrical shape) following the columnar shape of the tip portion 24. The clearance between the clearance portion 61 and the front end portion 24 is, for example, 0.1 to 1 mm. When the first sleeve 15A is placed on the opening edge portion 32 of the base material 13 in a step before the thermal expansion step, the tip portion 24 of the first sleeve 15A is prevented from interfering with the second step portion 33 of the first through-hole portion 14A.

[0099] The shape of the clearance portion 61 is not limited to that shown in FIG. 8. The clearance portion 61 may be formed as in a second modified example shown in FIG. 9. The clearance portion 61 may be formed as a chamfered portion that is chamfered so that the inner diameter increases in a direction approaching the base end 26 of the first sleeve 15A (the direction D2 opposite to the insertion direction D1 of the first sleeve 15A). The clearance portion 61 is formed in an inverted frustum shape that is concentric with the main body 14AA of the first through-hole portion 14A. The inner diameter of the clearance portion 61 is formed slightly larger than the diameter of the tip portion 24 of the first sleeve 15A. The clearance between the clearance portion 61 and the front end portion 24 is, for example, 0.1 to 1 mm. This shape also allows the tip of the tip portion 24 to escape from the second step portion 33 when the first sleeve 15A is placed on the opening edge portion 32.

[0100] According to this modified example, the following can be said: A length L1 from a base end on the opposite side to the tip in the insertion direction D1 of one or more sleeves 15 to the first step 23 is smaller than a length L2 of a tip portion 24 in the insertion direction D1, and one or more through-hole portions 14 have a clearance portion 61 formed with a diameter larger than the tip portion 24 to prevent interference between the base material 13 and the tip portion 24 before thermal expansion.

[0101] According to this configuration, when the first sleeve 15A is placed on the opening edge 32 of the first through-hole portion 14A prior to the insertion of the first sleeve 15A, it is possible to prevent the tip portion 24 of the first sleeve 15A from interfering with the structural portion (second step portion 33) that receives the first step portion 23 of the first through-hole portion 14A. This makes it possible to prevent a problem in which the first sleeve 15A cannot be placed on the opening edge portion 32 of the first through-hole portion 14A. The above-described embodiment and modified examples can be implemented with various substitutions and modifications. [Example]

[0102] The first sleeve (stepped sleeve) was made of SUS316 stainless steel with a first step diameter of 4.5 mm (dimensional tolerance 0 to -0.02 mm) and a tip diameter of 2.5 mm (dimensional tolerance 0 to -0.02 mm). A through hole was formed in the center of the first sleeve, extending axially, with an inner diameter of 2 mm (inner diameter 1 mm inside the tip).

[0103] The second sleeve was made of ceramics (alumina (Al2O3)) and had a cylindrical shape with a diameter of 5 mm (dimension tolerance 0 to -0.04 mm). A through hole with an inner diameter of 1.2 mm was formed in the center of the second sleeve and extended in the axial direction.

[0104] A shower plate constituting a shower head was prepared under the following conditions. The substrate was made of A5052 aluminum alloy in the shape of a square plate measuring 110 mm in length, 110 mm in width, and 10 mm in thickness. Two substrates were prepared. In one substrate, 16 first through-holes (stepped through-holes) penetrating in the thickness direction were formed (4 rows x 4 columns) so as to be distributed in a lattice pattern. Each of the first through-holes was formed to correspond to each lattice point while changing the inner diameter dimension. 16 first sleeves were inserted into the 16 first through-holes. Of the 16 results, 8 results are shown in Table 1 as Examples A1 to A5 and Comparative Examples A1 to A3. In Table 1, dimension 1 indicates the inner diameter (unit: mm) of the large diameter part of the first through-hole part, and dimension 2 indicates the inner diameter (unit: mm) of the small diameter part (second step part) of the first through-hole part.

[0105] [Table 1]

[0106] In addition, 16 second through-hole portions (straight through-hole portions) penetrating the other substrate in the thickness direction were formed (4 rows x 4 columns) so as to be distributed in a lattice pattern. Each of the second through-hole portions was formed to correspond to each lattice point while changing the dimensions. 16 second sleeves were inserted into the 16 second through-hole portions. Of the 16 results, 8 examples are shown in Table 2 below as Examples B1 to B3 and Comparative Examples B1 to B5. In Table 2, the dimensions indicate the inner diameter (unit: mm) of the second through-hole portion.

[0107] [Table 2]

[0108] In each of the examples and comparative examples, the process of heating the substrate to a processing temperature higher than the usage temperature to thermally expand it was performed by sandwiching the substrate between a first plate and a second plate from above and below to form a unit, and placing the unit on top of a heater.

[0109] In Example A1, the first sleeve dropped into the first through-hole by its own weight, by setting the thermal expansion step (fitting temperature) to 350° C. or higher. When the first sleeve fitted in Example A1 was cooled from the above-mentioned state of 350° C. or higher to 200° C., it was inspected whether it fell off from the substrate, and it was judged not to have fallen off (evaluation ◯).

[0110] In Examples A2 and A3, the thermal expansion step (fitting temperature) was set to 400° C. or higher, and the first sleeve could be inserted into the first through-hole by pushing the first sleeve downward with a small hammer or the like. The first sleeve fitted in Examples A2 and A3 was cooled from the above-mentioned state of 400° C. or higher to 200° C., and then inspected to see if it fell off from the substrate. It was determined that it did not fall off (evaluation ◯).

[0111] FIG. 11 shows a graph corresponding to dimension 2 of Example A3. In the graph, the first sleeve made of SUS316 stainless steel is shown by two lines, an upper limit and a lower limit, taking into account the dimensional tolerance. As shown in the graph, the base material made of A5052 aluminum alloy has a larger linear expansion coefficient than the first sleeve made of SUS316 stainless steel. For this reason, in the process of thermally expanding at 400°C or higher, the inner diameter of the small diameter part of the first through hole part is calculated to be reversed to the outer diameter of the tip part of the first sleeve. When the temperature is then returned to normal temperature, the inner diameter of the small diameter part of the first through hole part becomes smaller than the outer diameter of the tip part of the first sleeve. It is considered that this causes the base material to be in an elastically deformed state and to hold the first sleeve.

[0112] In Examples A4 and A5, the thermal expansion step (fitting temperature) was set to 400° C. or higher, and the first sleeve was struck downward with a small hammer or the like, thereby allowing the first sleeve to be inserted into the first through-hole portion. The first sleeve fitted in Examples A4 and A5 was cooled from the above-mentioned state of 400° C. or higher to 200° C., and then inspected to see whether it fell off from the substrate. It was determined that it did not fall off (evaluation ◯).

[0113] FIG. 10 shows a graph corresponding to dimension 1 of Example A4. In the graph, the first sleeve made of SUS316 stainless steel is shown by two lines, an upper limit and a lower limit, taking into account the dimensional tolerance. As shown in the graph, the base material made of A5052 aluminum alloy has a larger linear expansion coefficient than the first sleeve made of SUS316 stainless steel. For this reason, in the process of thermally expanding at 400°C or higher, the inner diameter of the large diameter part of the first through hole part is calculated to be reversed to the outer diameter of the first step part of the first sleeve. When the temperature is then returned to normal temperature, the inner diameter of the large diameter part of the first through hole part becomes smaller than the outer diameter of the first step part of the first sleeve. It is considered that this causes the base material to be in an elastically deformed state and to hold the first sleeve.

[0114] In Examples A1 to A5, it is understood that no gap is generated between the first sleeve and the first through hole portion near the usage temperature because the first sleeve did not actually fall off from the substrate at 200° C. This result supports the hypothesis that the substrate that is in an elastically deformed state at room temperature is also in an elastically deformed state at a usage temperature near 200° C., and no gap is generated between the first sleeve and the first through hole portion.

[0115] In Comparative Examples A1 and A2, the first sleeve could be inserted into the first through-hole at room temperature (RT) (fitting temperature = room temperature). In Comparative Examples A1 and A2, when the temperature was raised to 200°C, the first sleeve was judged to have fallen off the substrate (evaluation: ×).

[0116] In comparison example A3, the thermal expansion process (fitting temperature) was set to 400°C or higher, and the first sleeve was struck downward with a small hammer or the like, but the first sleeve could not be inserted into the first through hole portion (evaluation: ×).

[0117] In Example B1, the thermal expansion step (fitting temperature) was set to 350° C. or higher, and the second sleeve could be inserted into the second through-hole by pushing the second sleeve downward with a small hammer or the like. The first sleeve fitted in Example B1 was cooled from the above-mentioned state of 350° C. or higher to 200° C., and then inspected to see if it fell off from the substrate. It was determined that it did not fall off (evaluation ◯).

[0118] In Examples B2 and B3, the thermal expansion step (fitting temperature) was set to 400° C. or higher, and the second sleeve could be inserted into the second through-hole by pushing the second sleeve downward with a small hammer or the like. The first sleeve fitted in Examples B2 and B3 was cooled from the above-mentioned state of 400° C. or higher to 200° C., and then inspected to see if it fell off the base material. It was determined that it did not fall off (evaluation ◯).

[0119] FIG. 12 shows a graph corresponding to Example B3. In the graph, the second sleeve made of alumina (Al2O3) is shown by two lines, an upper limit and a lower limit, taking into account the dimensional tolerance. As shown in the graph, the base material made of A5052 aluminum alloy has a larger linear expansion coefficient than the second sleeve made of alumina (Al2O3). Therefore, in the process of thermally expanding at 400°C or higher, the inner diameter of the second through hole portion is theoretically reversed to the outer diameter of the second sleeve. When the temperature is then returned to normal, the inner diameter of the second through hole portion becomes smaller than the outer diameter of the second sleeve. It is considered that this causes the base material to be in an elastically deformed state and to hold the second sleeve.

[0120] In Examples B1 to B3, it is understood that no gap is generated between the second sleeve and the second through hole portion near the usage temperature because the second sleeve did not actually fall off from the substrate at 200° C. This result supports the hypothesis that the substrate that is in an elastically deformed state at room temperature is also in an elastically deformed state at a usage temperature near 200° C., and no gap is generated between the second sleeve and the second through hole portion.

[0121] In Comparative Examples B1 and B2, the second sleeve could be inserted into the second through-hole at room temperature (RT) (fitting temperature = room temperature). In Comparative Examples B1 and B2, when the temperature was raised to 200°C, the second sleeve fell off the substrate (evaluation: ×).

[0122] In Comparative Example B3, the second sleeve could be inserted into the second through-hole by setting the thermal expansion step (fitting temperature) at 180° C. In this Comparative Example B3, when the temperature was raised to 200° C., the second sleeve was judged to have fallen off the substrate (evaluation: ×).

[0123] In comparative examples B4 and B5, the thermal expansion process (fitting temperature) was set to 400°C or higher, and the first sleeve was pushed downward with a small hammer or the like, but the second sleeve could not be inserted into the second through-hole portion (evaluation: ×). [Explanation of symbols]

[0124] 11. Shower Head 12 Shower plate 13 Base material 14 Through hole 14A 1st through hole section 14B 2nd through hole section 15 Sleeve 15A First Sleeve 15B Second Sleeve 151 End face 16 Membrane 22 Outer surface 23 First Stage D1 Insertion direction D2 opposite direction 24 Tip part 25 Tip 26 proximal end 27 Tapered Surface 27A First tapered surface 27B Second tapered surface 31 Inner surface 32 Opening edge 33 Second Stage 34 Large diameter part 35 Expanded diameter surface 35A 1st expanded diameter surface 35B 2nd expanded diameter surface 48 Heater 51 Furnace 52 1st spindle 53 Second weight 61 Relief

Claims

1. A substrate having one or more through holes extending therethrough in a thickness direction; one or more sleeves inserted into the base material so as to cover an inner circumferential surface of the through-hole portion, the one or more sleeves having a linear expansion coefficient smaller than a linear expansion coefficient of the base material; a coating formed across a surface of the substrate and an end surface of the sleeve; Equipped with an inner diameter of the one or more through-hole portions is smaller than an outer diameter of the sleeve at an operating temperature higher than room temperature; the one or more sleeves have one or more tapered surfaces on an outer circumferential surface, each of the one or more tapered surfaces decreasing in diameter in a direction approaching a tip end, the one or more tapered surfaces including a first tapered surface provided near the tip end; The one or more sleeves have a first step and a tip portion that is provided on the tip side of the first step and has a smaller diameter than the first step, the one or more tapered surfaces include a second tapered surface provided in the first step portion, the one or more through hole portions have one or more expanding diameter surfaces on an inner circumferential surface, each of the one or more expanding diameter surfaces having a diameter increasing in a direction approaching a base end opposite to the tip end of the sleeve, the one or more expanding diameter surfaces including a first expanding diameter surface provided in the vicinity of an opening edge portion, The one or more through hole portions have a second step portion with which the first step portion can come into contact, The one or more diverging surfaces include a second diverging surface provided in the second step.

2. 2. The showerhead of claim 1, wherein a length from a base end of the one or more sleeves opposite the tip end to the first step is greater than a length of the tip portion in an axial direction of the sleeve.

3. a length from a base end of the one or more sleeves opposite to the tip end to the first step portion is shorter than a length of the tip portion in an axial direction of the sleeve; 2. The showerhead of claim 1, wherein the one or more through-holes have a recess formed with a diameter larger than that of the tip portion, preventing interference between the base material and the tip portion before thermal expansion.

4. The showerhead according to any one of claims 1 to 3, wherein the operating temperature is 100 to 250°C.

5. A showerhead described in any one of claims 1 to 4, wherein the processing temperature is 100°C or more higher than the usage temperature.

6. 6. The showerhead according to claim 1, wherein an inner diameter of the one or more through holes is equivalent to an outer diameter of the sleeve at a temperature higher than the usage temperature.

7. 1. A method for manufacturing a showerhead for use at an operating temperature, comprising: a substrate having one or more through holes penetrating in a thickness direction and upper opening edges of the one or more through holes; one or more sleeves inserted into the substrate so as to cover inner circumferential surfaces of the one or more through holes, the one or more sleeves having a linear expansion coefficient smaller than a linear expansion coefficient of the substrate and an outer diameter larger than an inner diameter of the one or more through holes at an operating temperature higher than room temperature; and a coating formed across a surface of the substrate and an end face of the sleeve, the method comprising: placing the one or more sleeves over the one or more opening edges; heating the substrate to a processing temperature that is greater than the use temperature to cause thermal expansion; inserting the one or more sleeves into the one or more through-hole portions of the base material that has been heated to a processing temperature higher than the use temperature and thermally expanded; cooling the base material and fitting the sleeve into the through hole; forming a coating across a surface of the substrate and an end surface of the sleeve; Equipped with The step of heating the substrate to a processing temperature higher than the use temperature to thermally expand the substrate includes a step of heating the substrate and the sleeve in a furnace that encloses the substrate and the sleeve; a step of inserting the one or more sleeves into the one or more through hole portions of the base material that has been heated to a processing temperature higher than the usage temperature and thermally expanded, the step being performed by applying a load of a weight placed on the upper side of the one or more sleeves that are placed on the upper sides of the one or more opening edges, the weight having approximately the same linear expansion coefficient as the base material.

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