Method for manufacturing nozzle plate

Abstract

This method for manufacturing a nozzle plate (110) comprises: a first step for forming a first hole (305) which communicates with a first surface (Bb) of a single crystal silicon substrate (B) having a {100} surface crystal orientation and which is longer in the [100] direction than in the [010] direction, and a second hole (306) which can communicate with the first hole (305) and a second surface (Ba) of the single crystal silicon substrate (B); and a second step in which the first hole (305) and the second hole (306) are expanded by anisotropic wet etching with respect to the single crystal silicon substrate (B), thereby forming a nozzle flow path (100) provided with a nozzle tapered section (20) having a {111} plane, and a straight communication section (10) continuous with the nozzle tapered section (20).

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a nozzle plate. Background Art

[0002] Conventionally, it is known to manufacture a nozzle plate of a droplet discharge head of a droplet discharge device from a single crystal silicon substrate, as shown in Patent Document 1. Nozzle flow paths are formed on the nozzle plate by anisotropic wet etching.

[0003] Patent Document 1: Japanese Patent No. 5519263

[0004] However, when anisotropic wet etching is performed on a single crystal silicon substrate whose surface crystal orientation is the {100} plane, the corrosion action proceeds in a certain direction. Therefore, only a nozzle flow path can be formed in which the opening of the surface opposite to the droplet discharge surface is square. If such a nozzle plate is joined to another plate whose cross-sectional shape of the ink flow path is, for example, rectangular, the shape of the joint between the ink flow path and the nozzle flow path is inconsistent. Therefore, the resistance during ink ejection becomes stronger, and the driving voltage needs to be increased. In addition, the curved liquid surface becomes unstable and ejection defects occur, and the ejection characteristics deteriorate. Furthermore, since there are restrictions on the shape of the nozzle flow path, it is difficult to increase the density of the nozzle openings arranged side by side in a row on the single crystal silicon substrate if the volume of the nozzle flow path is to be ensured. Summary of the invention

[0005] In order to solve the above problems, an object of the present invention is to provide a method for manufacturing a nozzle plate capable of achieving both high density of nozzle openings and good injection characteristics.

[0006] The invention described in claim 1 is a method for manufacturing a nozzle plate of a liquid droplet ejection head, comprising:

[0007] The first step is to form a first hole connected to a first surface of a single crystal silicon substrate whose surface crystal orientation is a {100} plane and which is longer in the

[100] direction than in the

[010] direction, and a second hole capable of connecting to the first hole and the second surface of the single crystal silicon substrate; and

[0008] In the second step, the first hole and the second hole are enlarged by anisotropic wet etching on the single crystal silicon substrate to form a nozzle flow path, wherein the nozzle flow path includes a nozzle tapered portion having a {111} surface and a straight connecting portion continuous with the nozzle tapered portion.

[0009] The invention described in claim 2 is a method for manufacturing a nozzle plate described in claim 1,

[0010] In the first step, the length of the second hole in the

[001] direction is formed to be substantially equal to the length from the end of the second hole on the first surface side to the end of the first hole in the

[100] direction.

[0011] The invention described in claim 3 is a method for manufacturing a nozzle plate described in claim 1,

[0012] In the first step, the length of the second hole in the

[001] direction is formed to be longer than the length from the end of the second hole on the first surface side to the end of the first hole in the

[100] direction.

[0013] A stepped surface is formed on the tapered portion of the nozzle.

[0014] The invention described in claim 4 is a method for manufacturing a nozzle plate described in any one of claims 1 to 3,

[0015] The centers of the first hole and the second hole coincide with each other.

[0016] The invention described in claim 5 is a method for manufacturing a nozzle plate described in any one of claims 1 to 3,

[0017] In the first step, the bottom of the first hole is formed in a stepped shape.

[0018] The invention described in claim 6 is a method for manufacturing a nozzle plate described in any one of claims 1 to 3,

[0019] The first step includes the following steps:

[0020] The single crystal silicon substrate is deep-drilled from the first surface to the middle by dry etching to form a third hole,

[0021] Next, a nozzle mask layer is formed along the inner surface of the third hole.

[0022] Next, the nozzle mask layer formed at the bottom of the third hole is removed.

[0023] The first hole is formed by further digging the third hole.

[0024] The second step forms a nozzle flow path including a nozzle straight portion that is continuous from the end of the nozzle tapered portion on the second surface side.

[0025] The invention described in claim 7 is a method for manufacturing a nozzle plate described in any one of claims 1 to 3,

[0026] The single crystal silicon substrate has a non-wet etching layer formed on the second surface.

[0027] The invention described in claim 8 is a method for manufacturing a nozzle plate described in any one of claims 1 to 3,

[0028] The method includes a third step of increasing the diameter of the opening on the first surface side and / or the second surface side of the nozzle flow path.

[0029] According to the present invention, it is possible to provide a method for manufacturing a nozzle plate capable of achieving both high density of nozzle openings and good injection characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a perspective view of a liquid droplet ejection device equipped with a liquid droplet ejection head formed by stacking nozzle plates.

[0031] Figure 2A This is a top view of the nozzle plate viewed from the [0 0 1] direction.

[0032] Figure 2B This is a top view of the nozzle plate viewed from the [0 0 -1] direction.

[0033] Figure 3 This is a cross-sectional view of the nozzle plate according to the first embodiment as viewed from the [0 1 0] direction.

[0034] Figure 4 It is a perspective cross-sectional view showing a nozzle flow path formed by the method for manufacturing the nozzle plate according to the first embodiment.

[0035] Figure 5 It is a cross-sectional view of the method for manufacturing the nozzle plate according to the first embodiment as viewed from the [0 1 0] direction and a plan view of the method as viewed from the [0 01] direction.

[0036] Fig. 6A This is a cross-sectional view showing the progress of etching in the second step as viewed from the [1 0 0] direction.

[0037] Figure 6B This is a cross-sectional view showing the progress of etching in the second step as viewed from the [0 1 0] direction.

[0038] Fig. 7A This is a cross-sectional view of the nozzle flow path formed when the centers of the opening hole and the nozzle hole are offset in the [1 0 0] direction as viewed from the [0 1 0] direction.

[0039] Figure 7B This is a cross-sectional view of a nozzle flow path viewed from the [0 1 0] direction, in which the length of the nozzle hole in the [0 0 1] direction is formed to be longer than the length from the end of the opening hole in the [1 00] direction to the end of the nozzle hole on the bonding surface side.

[0040] Figure 7C This is a cross-sectional view of a nozzle flow path in which the length of the nozzle hole in the [0 0 1] direction is shorter than the length from the end of the opening hole in the [1 00] direction to the end of the nozzle hole on the bonding surface side when viewed from the [0 1 0] direction.

[0041] Figure 8 It is a cross-sectional view of the method for manufacturing the nozzle plate according to the second embodiment as viewed from the [0 1 0] direction and a plan view of the method as viewed from the [0 01] direction.

[0042] Fig. 9A This is a cross-sectional view of the nozzle plate according to the third embodiment as viewed from the [0 1 0] direction.

[0043] Fig. 9B This is a cross-sectional view of the nozzle plate according to the modification of the third embodiment as viewed from the [0 1 0] direction.

[0044] Fig.10 It is a perspective cross-sectional view showing a nozzle flow path formed by the method for manufacturing a nozzle plate according to the third embodiment.

[0045] Fig.11 It is a cross-sectional view of the method for manufacturing the nozzle plate according to the third embodiment as viewed from the [0 1 0] direction and a plan view of the method as viewed from the [0 01] direction.

[0046] Fig. 12A This is a cross-sectional view of a nozzle flow path of Example 1 and an intermediate structure that becomes the nozzle flow path, viewed from the [0 1 0] direction.

[0047] Fig. 12B This is a plan view of a nozzle flow path of Example 1 and an intermediate structure that becomes the nozzle flow path, as viewed from the [0 0 1] direction.

[0048] Fig.13A This is a cross-sectional view of a nozzle flow path of Example 2 and an intermediate structure that becomes the nozzle flow path, viewed from the [0 1 0] direction.

[0049] Fig. 13B This is a plan view of a nozzle flow path of Example 2 and an intermediate structure that becomes the nozzle flow path, as viewed from the [0 0 1] direction.

[0050] Fig.14A This is a cross-sectional view of a nozzle flow path of Example 3 and an intermediate structure that becomes the nozzle flow path, viewed from the [0 1 0] direction.

[0051] Fig. 14B This is a plan view of a nozzle flow path of Example 3 and an intermediate structure that becomes the nozzle flow path, as viewed from the [0 0 1] direction. DETAILED DESCRIPTION

[0052] Hereinafter, the preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the scope of the invention is not limited to the illustrated examples. In addition, in the following description, the same reference numerals are used for parts having the same functions and structures, and their descriptions are omitted.

[0053] In addition, the Miller indices describing the crystal planes and directions are generally defined as follows, and this specification is also based on this.

[0054] (hkl): specific surface

[0055] [hkl]: Equivalent surface

[0056] [hkl]: Specific direction

[0057] <h k l> : Equivalent direction

[0058] In addition, unless otherwise specified, in the examples in the specification, it is described as follows:

[0059] Wafer bonding side: (0 0 1) surface

[0060] Wafer discharge side surface: (0 0 -1) surface,

[0061] Four conical surfaces of the conical portion of the nozzle: (1 1 1) surface, (-1 1 1) surface, (1 -1 1) surface, and (-1 -1 1) surface

[0062] The vertical surface constituting the nozzle tapered portion and the two opposing surfaces with long sides of the four surfaces constituting the side surfaces of the straight connecting portion: the (0 1 0) surface and the (0 -1 0) surface

[0063] Among the four side surfaces constituting the straight connecting portion, two opposing surfaces having short sides are the (1 0 0) surface and the (-1 0 0) surface.

[0064] However, of course, as long as the surface and direction are equivalent to the described content, they are not limited to the description.

[0065] In addition, regarding the display method of the Miller index, the symbol indicating a negative index is generally a bar above the index as in (1) and (2) of the following formula 1. However, in this specification, it is expressed as in (1') and (2') below for convenience.

[0066] [Formula 1]

[0067]

[0068] (h -kl)…(1′)

[0069] [h -kl]…(2′)

[0070] [First embodiment]

[0071] A method for manufacturing the nozzle plate 110 according to the first embodiment of the present invention will be described.

[0072] The method for manufacturing the nozzle plate 110 of the first embodiment is to install the nozzle plate 110 on the Figure 1 The method for manufacturing the nozzle plate 110 (see FIG. 2 ) of the liquid droplet discharge head 2 of the liquid droplet discharge device 1 as shown.

[0073] (Nozzle Plate)

[0074] The nozzle plate 110 is formed from a single crystal silicon substrate B whose surface crystal orientation is the {100} plane. Figure 2A is a top view showing the (001) surface of the nozzle plate 110, Figure 2B It is a plan view showing the (00-1) plane of the nozzle plate 110 .

[0075] like Figure 2B As shown, in the nozzle plate 110 , a plurality of nozzle openings N are provided on the discharge surface (second surface) Ba ((00-1) surface) so as to be arranged in a row along the

[010] direction.

[0076] The nozzle plate 110 is provided with a plurality of nozzle channels 100 penetrating from the bonding surface (first surface) Bb ((001) surface) to the discharge surface Ba.

[0077] The nozzle plate 110 is bonded to another plate having an ink flow path on its bonding surface Bb by an adhesive or the like. Then, the liquid flowing in from the ink flow path is discharged from the nozzle opening N via the nozzle flow path 100 .

[0078] In addition, Figure 2B In FIG. 1 , only one row of nozzle openings N is shown, but multiple rows may be arranged along the

[100] direction.

[0079] Figure 3 This is a cross-sectional view of the nozzle plate 110 as viewed from the

[010] direction. Figure 4 1 is a perspective cross-sectional view of a nozzle flow path 100 .

[0080] like Figure 3 and Figure 4 As shown, the nozzle flow path 100 includes a straight communication portion 10, a nozzle tapered portion 20, and a nozzle opening N in this order from the bonding surface Bb.

[0081] {Straight connecting part}

[0082] The straight communication portion 10 is provided from the bonding surface Bb to the end portion of the nozzle tapered portion 20 on the bonding surface Bb side. That is, the straight communication portion 10 constitutes an opening portion of the nozzle flow path 100 on the bonding surface Bb side.

[0083] The straight connecting portion 10 is composed of a part of four planes ((100) plane, (-100) plane, (010) plane and (0-10) plane) whose crystal planes are {100} planes. Figure 2A and Figure 4 As shown, a set of opposing surfaces 10a of the straight connecting portion 10 are substantially parallel.

[0084] Moreover, if Figure 2A and Figure 4 As shown, among the sides where the surfaces constituting the straight connecting portion 10 intersect with the bonding surface Bb, the length along the

[100] direction of a pair of opposing surfaces 10a is longer than the length along the

[010] direction.

[0085] That is, the side formed by the surface constituting the straight connecting portion 10 and the surface constituting the bonding surface Bb is Figure 2A and Figure 4 By forming the straight connecting portion 10 in this way, the volume of the nozzle flow path 100 can be ensured, and the nozzle openings N can be arranged at a narrow pitch of the short side length of the elongated shape. That is, the density of the nozzle openings N in the nozzle plate 110 is increased.

[0086] In addition, Figure 2A and Figure 4 , the case where the opening on the bonding surface Bb side of the nozzle flow path 100 in the nozzle plate 110 is rectangular is illustrated, but the invention is not limited thereto. When the opening on the bonding surface Bb side of the nozzle flow path 100 is expanded by performing the third step (removal process) described later, the opening will inevitably become a rectangle. However, in the present invention, the third step is not an essential step. Therefore, the opening on the bonding surface Bb side of the nozzle flow path 100 in the nozzle plate 110 may be any shape corresponding to the shape of the opening pattern 303 described later, as long as it is an elongated shape.

[0087] {Nozzle cone}

[0088] The nozzle tapered portion 20 has a tapered surface 20a of a substantially constant angle in which the flow path area gradually increases from the discharge surface Ba toward the bonding surface Bb. More specifically, the nozzle tapered portion 20 is composed of the tapered surface 20a of four surfaces ((111) surface, (-111) surface, (1-11) surface, and (-1-11) surface) whose crystal surfaces are {111} surfaces, and a portion 20b of the four surfaces whose crystal surfaces are {100} surfaces.

[0089] In addition, the "flow path area" in the present invention refers to a cross-sectional area in a direction perpendicular to the ink discharge direction.

[0090] The angle θ1 formed between the tapered surface 20a of the nozzle tapered portion 20 and the axis parallel to the nozzle center axis (see Figure 3 ) is 15° or more. In the present invention, the tapered surface 20a is formed by anisotropically wet etching the single crystal silicon substrate B. Therefore, according to the etching characteristics of Si, the angle θ1 is 45°.

[0091] If the nozzle tapered portion 20 is provided, even when the meniscus of the liquid retreats to the deep part of the nozzle channel 100 due to high-speed driving, the shape of the meniscus and the discharge of liquid droplets can be stabilized.

[0092] {Nozzle opening}

[0093] The nozzle opening N is provided on the discharge surface Ba and is a circular, elliptical or polygonal hole from which liquid droplets are discharged. The nozzle opening N communicates with the end of the nozzle tapered portion 20 on the discharge surface Ba side.

[0094] (Method for manufacturing nozzle plate)

[0095] The method for manufacturing the nozzle plate 110 includes, for example, Figure 5 Steps 1 to 3 are shown.

[0096] In the first step, an intermediate structure 300 having an opening hole (first hole) 305 and a nozzle hole (second hole) 306 described later is formed. In the second step, the nozzle flow path 100 is formed by performing anisotropic wet etching on the intermediate structure 300 formed in the first step. In the third step, the nozzle plate 110 formed in the second step is appropriately removed.

[0097] {First step: intermediate structure forming step}

[0098] (Step 1-1)

[0099] like Figure 5 As shown, the first step is further divided into a plurality of steps.

[0100] First, as step 1-1, a mask layer is formed on the surface of a single crystal silicon substrate B. Specifically, a surface mask layer 301 is formed on a bonding surface Bb of single crystal silicon whose surface crystal orientation is {100}. Also, a back mask layer 302 is formed on a discharge surface Ba.

[0101] Hereinafter, when no particular distinction is made between the front mask layer 301 and the back mask layer 302 , they are collectively referred to as a “mask layer” as described above.

[0102] The single crystal silicon substrate B is a plate-shaped member with a thickness of about 100 μm to 725 μm. By using single crystal silicon as the base material of the nozzle plate 110, it can be processed with high precision. As a result, the nozzle plate 110 with less positional error and shape deviation can be formed.

[0103] The material for forming the mask layer may be any material as long as it can stop the progress of etching during anisotropic wet etching described later, or any material that is not removed by etching.

[0104] The material of the mask layer is not particularly limited if it satisfies these conditions, but for example, oxides such as SiO2 (silicon oxide) can be used for the mask layer. In addition, metal films based on Al (aluminum), Cr (chromium), etc., resins, etc. can be used for the mask layer.

[0105] In the present invention, SiO2 is used as a mask layer.

[0106] The thickness of the mask layer is not particularly limited, but is preferably 0.1 μm to 50 μm, and particularly preferably 0.5 μm to 20 μm. The mask layer has a thickness of 0.5 μm or more, thereby improving the etching stop effect. The mask layer can be easily formed if the thickness is 20 μm or less.

[0107] However, when the mask layer is formed by the thermal oxidation method described above, the thickness of the mask layer is preferably set to 1 μm to 5 μm. In addition, the mask layer is not limited to a single-layer structure as shown in the figure, but may also be a multi-layer structure.

[0108] (Step 1-2)

[0109] Next, as the 1-2nd step, an elongated opening pattern 303 which becomes an opening portion on the bonding surface Bb side of the nozzle flow channel 100 is formed on the surface mask layer 301 .

[0110] In addition, in the present embodiment, the shape of the opening pattern 303 is a hexagonal shape having a longer side along the <100> direction, but is not limited thereto. The shape of the opening pattern 303 can be any shape as long as it is an elongated shape that is longer in the

[100] direction than in the

[010] direction. Therefore, the shape of the opening pattern 303 can be, for example, a rectangle, an ellipse, or a shape in which a short side of a rectangle is combined with a semicircle of the same diameter as the short side.

[0111] Specifically, first, a resist pattern is formed on the surface mask layer 301 by a known photolithography technique.

[0112] <Resist pattern>

[0113] In the formation of the resist pattern, a positive photoresist or a negative photoresist can be used. As the positive photoresist and the negative photoresist, known materials can be used. For example, as the negative photoresist, ZPN-1150-90 manufactured by Zeon Corporation of Japan can be used. In addition, as the positive photoresist, OFPR-800LB manufactured by Tokyo Ohka Kogyo Co., Ltd. and OEBR-CAP112PM manufactured by the same company can be used.

[0114] A resist layer is formed by coating to a predetermined thickness using a spin coater or the like. Then, a pre-baking treatment is performed under conditions such as 110° C. for 90 seconds.

[0115] In order to improve the adhesion, HMDS treatment can also be implemented before the resist coating. HMDS treatment can use an organic material called hexamethyldisilazane, such as OAP (hexamethyldisilazane, manufactured by Tokyo Ohka Industry Co., Ltd.). Similar to the resist coating, HMDS can also be applied by a spin coater. In addition, even if HMDS is exposed to hexamethyldisilazane vapor, the effect of improving adhesion can be expected.

[0116] After the resist layer is formed, the resist layer is exposed using a predetermined mask and an aligner. For example, in the case of a contact aligner, the resist layer is exposed at about 50 mJ / cm 2 Then, the photosensitive part of the resist layer is removed by immersing in a developer (for example, NMD-3 manufactured by Tokyo Ohka Kogyo Co., Ltd. for 60 to 90 seconds). Thus, a resist pattern is formed on the surface mask layer 301.

[0117] After forming the resist pattern, the surface mask layer 301 is dry-etched using the resist pattern as a mask to form an opening pattern 303. After forming the opening pattern 303, the resist pattern is removed.

[0118] <Dry Etching>

[0119] In dry etching, an RIE (Reactive Ion Etching) device can be used. In addition, a dry etching device such as an ICP (Inductively Coupled Plasma)-RIE etching device that uses an inductively coupled method as a discharge form can be used. In addition, as a process gas, CHF3 (trifluoromethane), CF4 (tetrafluoromethane), etc. can be used.

[0120] As an example, RIE-100C, a dry etching apparatus manufactured by SUMCO Co., Ltd., is used. The opening pattern 303 can be formed by etching for a predetermined time under the conditions of a CHF 3 gas flow rate of 80 sccm, a pressure of 3 Pa, and an RF power of 90 W.

[0121] <Removal of resist pattern>

[0122] In addition, as a method for removing the resist pattern, for example, there can be mentioned a wet process using acetone or an acid solution, and a dry process using oxygen plasma.

[0123] (Steps 1-3)

[0124] Next, as the first to third steps, the single crystal silicon substrate B below the opening pattern 303 is deep-etched by dry etching to form the opening hole 305 .

[0125] (Steps 1-4)

[0126] Next, as the 1st-4th step, the nozzle pattern 304 which becomes the nozzle opening N is formed.

[0127] The method for forming the nozzle pattern 304 is substantially the same as the method for forming the opening pattern 303 in the first-second step. The nozzle pattern 304 in the present embodiment is a square (diamond shape) having sides in the <110> direction.

[0128] The nozzle pattern 304 is formed so that the center thereof substantially coincides with the center of the opening pattern 303 when viewed from the bonding surface Bb and the discharge surface Ba. Hereinafter, this condition is referred to as “condition 1”.

[0129] (Steps 1-5)

[0130] Next, as step 1-5, the single crystal silicon substrate B under the nozzle pattern 304 is deep-drilled by dry etching to form the nozzle hole 306 .

[0131] The nozzle hole 306 is formed so that the length a in the

[001] direction substantially matches the length b from the end of the nozzle hole 306 on the bonding surface Bb side to the end of the opening hole 305 in the

[100] direction. This condition is hereinafter referred to as “Condition 2”.

[0132] In the 1st to 5th steps, if Figure 5As shown, the nozzle hole 306 is preferably formed to communicate with the opening hole 305. If the intermediate structure 300 that communicates the opening hole 305 with the nozzle hole 306 is formed at the time of the first step, the fluidity of the solution for anisotropic wet etching used in the second step becomes better. Therefore, the anisotropic wet etching is always performed with a fresh solution. In addition, the hydrogen gas generated during the anisotropic wet etching is uniformly and efficiently released through each nozzle flow path 100. As a result, the wet etching is performed uniformly in each nozzle flow path 100, and a uniform nozzle flow path 100 can be formed.

[0133] However, it is not necessary to form the intermediate structure 300 that allows the opening hole 305 and the nozzle hole 306 to communicate with each other at the time of the first step. The opening hole 305 and the nozzle hole 306 only need to be able to communicate with each other when anisotropic wet etching is performed in the second step.

[0134] In addition, in the above description, the example of advancing the first step in the order of step 1-1, step 1-2, step 1-3, step 1-4, and step 1-5 is illustrated, but the present invention is not limited to this. It is sufficient as long as at least three conditions are met: step 1-1 is performed first, step 1-2 is performed before step 1-3, and step 1-4 is performed before step 1-5.

[0135] Therefore, Condition 1 may also be rewritten as “the opening pattern 303 is formed so that the center thereof substantially coincides with the center of the nozzle pattern 304 when viewed from the bonding surface Bb and the discharge surface Ba”.

[0136] Condition 2 may also be rewritten as "the opening hole 305 is formed so that the length b from the end in the

[100] direction to the end on the bonding surface Bb side of the nozzle hole 306 is substantially equal to the length a of the nozzle hole 306 in the

[001] direction".

[0137] {Second step: anisotropic wet etching step}

[0138] Next, as a second step, anisotropic wet etching is performed on the intermediate structure 300 formed in the first step from both sides of the bonding surface Bb and the discharge surface Ba.

[0139] Fig. 6A This is a cross-sectional view showing the progress of etching in the second step as viewed from the

[100] direction side of the shorter side forming the opening hole 305. Figure 6B This is a cross-sectional view showing the progress of etching in the second step as viewed from the

[010] direction of the longer side where the opening hole 305 is formed.

[0140] like Fig. 6A and Figure 6BAs shown, in the second step, the opening hole 305 formed in the first to third steps and the nozzle hole 306 formed in the first to fifth steps are enlarged. Thus, the nozzle flow path 100 including the nozzle tapered portion 20 and the flat communication portion 10 is formed.

[0141] <Anisotropic wet etching>

[0142] In anisotropic wet etching, an alkaline aqueous solution is used, specifically, KOH (potassium hydroxide), TMAH (tetramethylammonium hydroxide), EDP (ethylenediaminecatechol), etc.

[0143] In the second step, if Fig. 6A As shown, when viewed from the

[100] direction, etching is performed along the

[010] direction and the [0-10] direction on each surface constituting the opening hole 305 and the nozzle hole 306 .

[0144] Therefore, the distance between the (010) plane and the (0-10) plane after the anisotropic wet etching is (the diameter of the nozzle pattern 304 + 2×the etching amount) μm (3).

[0145] In addition, if Figure 6B As shown, when viewed from the

[010] direction, etching is performed in the

[100] direction and the [-100] direction for each surface constituting the opening hole 305. Also, etching is performed in the

[100] direction or the [-100] direction for each surface constituting the nozzle hole 306.

[0146] Therefore, the distance between the (100) plane and the (−100) plane after the anisotropic wet etching is (the diameter of the nozzle pattern 304 + 6×the etching amount) μm (4).

[0147] Specifically, the diameter of the nozzle pattern 304 is set to 10 μm, and the etching amount is set to 20 μm. Then, according to the above formula (3), the distance between the (010) plane and the (0-10) plane after anisotropic wet etching is 10 μm+2×20 μm=50 μm.

[0148] Furthermore, according to the above formula (4), the distance between the (100) plane and the (-100) plane after the anisotropic wet etching is 10 μm+6×20 μm=130 μm.

[0149] On the other hand, the diameter of the nozzle pattern 304 is set to 30 μm, and the distance between the (010) plane and the (0-10) plane after anisotropic wet etching is set to 50 μm. Then, according to the above formula (3), 30 μm+2×x μm=50 μm, so the etching amount x is 10 μm.

[0150] Furthermore, according to the above formula (4), the distance between the (100) plane and the (-100) plane after the anisotropic wet etching is 30 μm+6×10 μm=90 μm.

[0151] As described above, the opening on the bonding surface Bb side of the nozzle channel 100 formed in the present invention is an elongated shape with a difference between the longer and shorter dimensions. This is preferred from the viewpoint of increasing the density of the nozzle openings N.

[0152] As described later, after the second step, when the removal process is performed as the third step so that the straight connecting portion 10 becomes substantially vertical, the distance between the (010) plane and the (0-10) plane becomes the shorter dimension of the opening on the bonding surface Bb side of the nozzle flow path 100. In addition, the distance between the (100) plane and the (-100) plane becomes the longer dimension.

[0153] Therefore, based on the above estimation, the nozzle pattern 304 is preferably formed to have its diameter as small as possible.

[0154] However, in the present embodiment, the ratio of the interval between the (010) plane and the (0-10) plane to the interval between the (100) plane and the (-100) plane, that is, the ratio of the dimension of the shorter side to the dimension of the longer side in the opening portion on the bonding surface Bb side of the nozzle flow path 100 after the third step, has a theoretical limit value of 1:3.

[0155] {Step 3: Removal process}

[0156] Back to Figure 5 After the second step, as a third step, the nozzle plate 110 is subjected to a removal process such as etching, grinding or polishing. Specifically, for example, the removal process is performed so that the straight connecting portion 10 becomes approximately vertical, and the diameter of the opening portion on the bonding surface Bb side of the nozzle flow path 100 after anisotropic wet etching is enlarged. Alternatively, the thickness of the nozzle plate 110 is adjusted to a desired size. Alternatively, the mask layer is removed.

[0157] In particular, even if the diameter of the nozzle pattern 304 is formed small as described above, the diameter of the nozzle opening N can be expanded by performing photolithography again from the discharge surface Ba side, transferring to the back mask layer 302, and removing by etching.

[0158] In addition, the third step is not an essential step, and may be appropriately performed as needed.

[0159] [Technical Effect]

[0160] As described above, the method for manufacturing the nozzle plate 110 of the first embodiment includes a first step of forming an intermediate structure 300 having an opening hole (first hole) 305 long in the

[100] direction and a nozzle hole (second hole) 306 capable of communicating with the opening hole 305 and the discharge surface Ba. In addition, the method includes a second step of enlarging the opening hole 305 and the nozzle hole 306 by anisotropic wet etching to form the nozzle flow path 100.

[0161] In the above description, the reason why the conditions 1 and 2 are described as “substantially consistent” is that both conditions may not completely consistent due to manufacturing errors. Fig. 7A Indicates a situation where condition 1 is not satisfied. Figure 7B This indicates a>b and does not satisfy condition 2. Figure 7C This indicates a<b and the condition 2 is not satisfied. 7A to 7C Both include a step difference on the tapered surface 20a.

[0162] As per Figure 5 and 7A to 7C As can be seen from the comparison, by satisfying the conditions 1 and 2, the nozzle flow path 100 having a smooth tapered surface 20a is formed.

[0163] On the other hand, 7A to 7C As shown in FIG. 1 , even if a manufacturing error related to condition 1 or condition 2 occurs in the first step, the nozzle opening N is located at the symmetrical center of the surface between the nozzle opening N and the step difference in the tapered surface 20a. This is because at least the portion of the nozzle tapered portion 20 that communicates with the nozzle opening N is formed by expanding the nozzle hole 306.

[0164] Thus, according to the above manufacturing method, even if there is a manufacturing error with respect to condition 1 or condition 2, the nozzle tapered portion 20 is necessarily formed from the nozzle hole 306. Moreover, the nozzle opening N is arranged without positional deviation at the symmetrical center of the surface between the nozzle opening N and the step difference in the tapered surface 20a. Therefore, even if there is a manufacturing error with respect to condition 1 or condition 2, the nozzle plate 110 having the nozzle flow path 100 with no eccentricity, symmetry of liquid flow, and stable ejection angle can be formed.

[0165] In addition, according to the above-mentioned manufacturing method, the nozzle plate 110 having the nozzle flow path 100 having an elongated opening on the bonding surface Bb can be formed. Therefore, the nozzle opening N can be made denser in the nozzle plate 110. In addition, when the nozzle plate 110 is joined to another plate having an elongated cross-sectional shape of the ink flow path, the shape of the joint portion between the nozzle flow path 100 and the ink flow path is consistent, thereby achieving good injection characteristics.

[0166] [Regarding other preferred structures]

[0167] As described above, the opening pattern 303 is not limited to a hexagonal shape having a long side along the <100> direction. In addition, the nozzle pattern 304 is not limited to a square shape having a side along the <110> direction.

[0168] However, considering the crystal orientation dependence of anisotropic wet etching, it is particularly preferable that the opening pattern 303 and the nozzle pattern 304 are set to the above-mentioned shapes. Figure 5 Anisotropic wet etching as shown.

[0169] In addition, as 7A to 7C , illustrates a case where a manufacturing error related to condition 1 or condition 2 occurs in the first process. Figure 7B As shown, a>b is achieved, and the nozzle channel 100 in which a stepped drooping surface is provided in the nozzle tapered portion 20 or an inclined surface (stepped surface) having a greater inclination than the angle θ1 is formed has a more excellent meniscus stability.

[0170] This is because, if the step surface is formed, even if the meniscus returns to the deep side of the nozzle channel 100, the expansion in the

[100] direction is suppressed, and the width in the

[100] direction is made equal to the width in the

[010] direction.

[0171] Furthermore, it is preferable that the step surface is formed so that the length from the discharge surface Ba to the end of the step surface on the bonding surface Bb side is 20 μm or more and 60 μm or less.

[0172] This is because the retreat of the liquid is rarely greater than 20 μm. If the above length is longer than 60 μm, the nozzle channel 100 cannot ensure a sufficient volume.

[0173] [Second embodiment]

[0174] Next, a method for manufacturing the nozzle plate 110 according to the second embodiment will be described.

[0175] In the second embodiment, after the opening pattern 303 is formed, patterns having different sizes and thicknesses are further formed to form the opening holes 305 having a stepped bottom.

[0176] exist Figure 8 2 shows a method for manufacturing the nozzle plate 110 according to the second embodiment.

[0177] In addition, since the 1-1 step is the same as that of the first embodiment, a detailed description thereof will be omitted.

[0178] (Step 1-2a)

[0179] In this embodiment, as step 1-2a, resist pattern formation and dry etching are performed twice. Specifically, after the opening pattern 303 is formed, a resist pattern having a size surrounding the opening pattern 303 is formed. In addition, dry etching is performed with an etching amount less than that of the opening pattern 303 to form a sub-pattern 303a.

[0180] After the opening pattern 303 and the sub-pattern 303a are formed, the resist pattern is removed.

[0181] (Steps 1-3)

[0182] After the opening pattern 303 and the sub-pattern 303 a are formed, the opening hole 305 is formed by performing deep digging processing using dry etching.

[0183] At this time, in the sub-pattern 303a, the surface mask layer 301 is first etched. Then, when the etching of the surface mask layer 301 is completed, the single crystal silicon substrate B is etched. On the other hand, in the opening pattern 303, there is no surface mask layer 301. Therefore, the single crystal silicon substrate B is immediately etched.

[0184] Therefore, even if etching is performed at the same time, the etching amount of the single crystal silicon substrate B is different between the opening pattern 303 and the sub-pattern 303a. That is, the single crystal silicon substrate B under the opening pattern 303 will be etched deeper. As a result, Figure 8 The bottom as shown is a stepped opening hole 305 .

[0185] In addition, the step formed in the first to third steps is preferably designed to satisfy a≈b≈c≈d regarding the length c in the

[001] direction and the length d in the

[100] direction. Similar to the first embodiment, if this condition is satisfied, the nozzle flow path 100 having a smooth tapered surface 20a is formed.

[0186] (1st to 4th, 1st to 5th steps, 2nd step, 3rd step)

[0187] After the opening hole 305 is formed, the nozzle hole 306 is formed through the 1-4 step and the 1-5 step. Then, in the second step, the nozzle channel 100 is formed by anisotropic wet etching.

[0188] After the second step, a removal process is appropriately performed as a third step.

[0189] [Technical Effect]

[0190] As described above, in the method for manufacturing the nozzle plate 110 according to the second embodiment, the sub-pattern 303 a having a size and a thickness different from those of the opening pattern 303 is formed, thereby forming the opening hole 305 having a stepped bottom.

[0191] According to this configuration, the ratio of the shorter dimension to the longer dimension of the opening on the bonding surface Bb side of the nozzle channel 100 can be made larger than 1: 3. Therefore, the nozzle openings N can be further densely formed.

[0192] [Modifications]

[0193] In the above description, the sub-pattern 303 a is formed after the opening pattern 303 is formed, but the present invention is not limited thereto and the order may be the opposite.

[0194] In the above description, the case where the resist pattern formation and dry etching are performed twice is exemplified, but the present invention is not limited thereto. That is, the opening hole 305 having a plurality of steps may be formed by performing the resist pattern formation and dry etching twice or more.

[0195] In the above description, the case where the formation of the resist pattern and the dry etching are performed multiple times is exemplified, but the present invention is not limited thereto. That is, the opening pattern 303 and the sub-pattern 303a may be formed at once by using a grayscale mask.

[0196] [Third Embodiment]

[0197] Next, based on Fig.11 , a method for manufacturing the nozzle plate 110 according to the third embodiment will be described.

[0198] The method for manufacturing the nozzle plate 110 according to the third embodiment is to form a nozzle plate having the structure shown in FIG. 9 and FIG. Fig.10 The nozzle flow path 100 of the nozzle straight portion 30 is shown.

[0199] {Nozzle straight part}

[0200] The nozzle straight portion 30 is a flow path that is continuous with the nozzle opening N on the discharge surface Ba side and is continuous with the nozzle tapered portion 20 on the adhesion surface Bb side.

[0201] In addition, the following examples Fig. 9A Although the nozzle straight portion 30 is constituted by a surface whose angle with an axis parallel to the nozzle center axis is 0° as shown, the present invention is not limited thereto.

[0202] like Fig. 9B As shown, the angle θ2 formed by the surface constituting the nozzle straight portion 30 and the axis parallel to the nozzle center axis is substantially constant at any position and 0°≦θ2<15° is sufficient.

[0203] In this embodiment, at least step 1-4 is followed by step 1-A to step 1-C. In this embodiment, the order of the steps is not particularly limited as long as the three conditions are met: step 1-1 is performed first, and step 1-2 is performed before step 1-3.

[0204] However, in practice, it is preferable to perform step 1-A to step 1-C before step 1-3. This is because if step 1-B described later is performed after step 1-3, a mask layer is also formed in the opening hole 305, and a step of removing the mask layer is required.

[0205] Therefore, hereinafter, the process is assumed to proceed in the order of step 1-1→step 1-4→step 1-A→step 1-B→step 1-C→step 1-5→step 1-2→step 1-3→step 2→step 3.

[0206] In addition, since the steps 1-1 to 1-5 are the same as those in the first embodiment, detailed descriptions thereof will be omitted.

[0207] (Step 1-A)

[0208] After the nozzle pattern 304 is formed in step 1-4, a predetermined amount of dry etching is performed on the single crystal silicon substrate B under the nozzle pattern 304 as step 1-A. Thus, a nozzle straight hole (third hole) 307 is formed. In this step, only the predetermined length of the nozzle straight portion 30 is etched.

[0209] (Step 1-B)

[0210] After the nozzle straight hole 307 is formed, as step 1-B, a nozzle mask layer 308 is formed along the inner surface of the nozzle straight hole 307. The method of forming the nozzle mask layer 308 is the same as the material and method of forming the mask layer.

[0211] (Step 1-C)

[0212] After the nozzle mask layer 308 is formed, the nozzle mask layer 308 formed at the bottom of the nozzle straight hole 307 is removed as the 1-C process. The nozzle mask layer 308 at the bottom of the nozzle straight hole 307 can be removed by dry etching using an RIE device or the like. However, in dry etching using an RIE device, the nozzle mask layer 308 formed on the side portion is more difficult to remove than the bottom portion by dry etching due to the verticality of the etchant. Therefore, the portion of the nozzle mask layer 308 formed at the bottom of the nozzle straight hole 307 is etched first, and the portion formed on the side portion is retained.

[0213] Furthermore, by setting the etching conditions in this step to a low pressure or a high bias voltage, the nozzle mask layer 308 on the side surface can be made more difficult to be etched.

[0214] (Steps 1-5, 1-2, 1-3)

[0215] After step 1-C, as step 1-5, the single crystal silicon substrate B is dry-etched to further deepen the nozzle straight hole 307 to form the nozzle hole 306. Then, the opening hole 305 is provided through steps 1-2 and 1-3.

[0216] (2nd step, 3rd step)

[0217] Then, as a second step, anisotropic wet etching is performed. At this time, the side surface of the nozzle straight hole 307 is protected by the nozzle mask layer 308. Therefore, the progress of etching of the side surface of the nozzle straight hole 307 is suppressed, and the nozzle straight portion 30 remains.

[0218] After the second step, a removal process is appropriately performed as a third step. In the present embodiment, in the third step, the nozzle mask layer 308 may be removed together with the mask layer.

[0219] [Technical Effect]

[0220] As described above, the method for manufacturing the nozzle plate according to the third embodiment includes steps 1-A to 1-C of forming the nozzle straight holes 307 and the nozzle mask layer 308 .

[0221] According to this structure, the nozzle channel 100 having the nozzle straight portion 30 can be formed. The nozzle straight portion 30 increases the resistance when the droplet is discharged, suppresses the vibration of the meniscus, and makes the meniscus shape more stable. Therefore, the nozzle plate 110 having the nozzle channel 100 with improved injection stability can be formed.

[0222] [Modifications]

[0223] Furthermore, in the above description, the case where the nozzle straight portion 30 is formed by forming the nozzle straight hole 307 and the nozzle mask layer 308 is exemplified, but the present invention is not limited thereto.

[0224] The nozzle straight portion 30 can be formed even when using the single crystal silicon substrate B provided with a non-wet etching layer having etching resistance.

[0225] The non-wet etching layer refers to a layer having etching resistance that can be formed by, for example, masking, thermal oxidation processing, or doping with high concentration of B (boron). In addition, a quartz layer formed by a method other than the above-mentioned thermal oxidation can also be provided on the single crystal silicon substrate B, and the quartz layer can be used as a non-wet etching layer.

[0226] Specifically, first, a non-wet etching layer having the same thickness as the nozzle plate 110 is provided on at least the discharge surface Ba side of the single crystal silicon substrate B. Then, the nozzle hole 306 is formed using such a single crystal silicon substrate B, and if anisotropic wet etching is performed, the non-wet etching layer plays the same role as the nozzle mask layer 308.

[0227] Therefore, even when the single crystal silicon substrate B including the non-wet etching layer is used, the nozzle straight portion 30 can be formed in the nozzle channel 100 .

[0228] Furthermore, the “length a of the nozzle hole 306 in the

[001] direction” in Condition 2 does not include the length in the

[001] direction of a portion having etching resistance such as the nozzle mask layer 308 and the non-wet etching layer.

[0229] Furthermore, in the manufacturing process of each embodiment, a step of forming at least one protective film may be added in order to use the nozzle plate 110 for a long period of time.

[0230] In this case, a step of forming a protective film covering at least a portion of the surface including the inside of the nozzle flow channel 100 is performed after the second step or the third step.

[0231] As the protective film, a film of a material that does not dissolve due to contact with ink can be selected and used, such as a metal oxide film (tantalum pentoxide, hafnium oxide, niobium oxide, titanium oxide, zirconium oxide, etc.), a metal silicate film containing silicon in the metal oxide film (tantalum silicate, hafnium silicate, niobium silicate, titanium silicate, zirconium silicate, etc.), SiC (silicon carbide) film, DLC (diamond-like carbon) film, and a material used in the formation of a mask layer. In addition, an organic film such as polyimide, polyamide, and polyparaxylene can also be used as the protective film.

[0232] The thickness of the protective film is not particularly limited, but can be, for example, 0.05 μm to 20 μm.

[0233] Example

[0234] Next, the results of evaluating the preferred configurations of the examples and comparative examples of the present invention will be described. The present invention will be specifically described below using examples, but the present invention is not limited to these examples.

[0235] [Sample production]

[0236] A nozzle plate 110 having 1280 nozzle channels 100 formed as in the following embodiments and comparative examples was manufactured. Then, it was bonded to a piezoelectric plate having an ink channel having an opening on the bonding surface having the same shape as the opening on the bonding surface Bb side of the nozzle channel 100, thereby forming an inkjet head as a droplet ejection head 2. Then, the inkjet head was mounted on an inkjet recording device as a droplet ejection device 1.

[0237] 12 to 14 are diagrams showing one nozzle channel 100 in the nozzle plate 110 of each embodiment. In each figure, the dotted line portion represents the intermediate structure 300 formed by the first step. In addition, the solid line portion represents the nozzle channel 100 in which the intermediate structure 300 is subjected to anisotropic wet etching in the second step, and the straight connecting portion 10 is removed in the third step so that the opening on the bonding surface Bb side is formed into a rectangular shape.

[0238] (Example 1)

[0239] The nozzle plate 110 is formed based on the manufacturing method of the second embodiment. Fig. 12A and Fig. 12B As shown, the intermediate structure 300 having the stepped bottom of the opening hole 305 is formed. Then, the nozzle flow path 100A having the nozzle tapered portion 20A, the straight communication portion 10A, and the nozzle opening N is formed.

[0240] also, Fig. 12B As shown, the shape of the opening pattern 303 is a hexagonal shape when viewed from above. In addition, the size of the opening on the bonding surface Bb side of the nozzle flow path 100A is 50 μm×130 μm, and the nozzle opening N is a circle with a diameter of 30 μm. In addition, the intermediate structure 300 formed by the first step is designed to satisfy a≈b≈c≈d.

[0241] (Example 2)

[0242] The nozzle plate 110 is formed based on the manufacturing method of the third embodiment. Fig.13A and Fig. 13B As shown, a nozzle flow path 100B including a nozzle straight portion 30B, a nozzle tapered portion 20B, a straight communication portion 10B, and a nozzle opening N is formed.

[0243] In addition, if Fig. 13B As shown, the shape of the opening pattern 303 is a shape obtained by combining the short side of a rectangle with a semicircle of the same diameter as the short side. In addition, the size of the opening on the bonding surface Bb side of the nozzle flow path 100B is 50μm×130μm. In addition, the length of the nozzle straight portion 30B in the

[001] direction is 30μm. In addition, as Fig.13A and Fig. 13BAs shown, in this embodiment, a circular nozzle pattern 304 with a diameter of 10 μm is formed in the first to fourth steps, and is expanded in the third step so that the nozzle opening N becomes a circular shape with a diameter of 30 μm.

[0244] In addition, the condition 2 is designed to satisfy a>b. Therefore, a vertical surface (step difference surface) having a length of 10 μm in the

[001] direction is formed in which a step is provided on the tapered surface 20aB of the nozzle tapered portion 20B.

[0245] (Example 3)

[0246] The nozzle plate 110 is formed based on the manufacturing method of the third embodiment. Fig.14A and Fig. 14B As shown, a nozzle flow path 100C including a nozzle straight portion 30C, a nozzle tapered portion 20C, a straight communication portion 10C, and a nozzle opening N is formed.

[0247] In addition, if Fig. 14B As shown, the shape of the opening pattern 303 is a rectangle whose length in the

[010] direction is longer than the length in the

[100] direction. In addition, the size of the opening portion on the bonding surface Bb side of the nozzle flow path 100C is 50 μm×130 μm. Fig.14A and Fig. 14B As shown, in this embodiment, a diamond-shaped nozzle pattern 304 with a diameter of 10 μm is formed through the first to fourth steps, and the nozzle opening N is expanded to a circular shape with a diameter of 30 μm through the third step.

[0248] In addition, regarding condition 2, a=b is set. Therefore, no step surface is formed on the tapered surface 20aC of the nozzle tapered portion 20C.

[0249] The nozzle straight portion 30C has a tapered surface with an angle θ2 of 8°, a length of 35 μm in the

[001] direction, and a diameter of 40 μm at the end on the bonding surface Bb side by appropriately setting etching conditions in the nozzle opening expansion step.

[0250] (Comparative Example 1)

[0251] The nozzle channel 100 is formed by a conventionally known method. That is, although the nozzle tapered portion 20 and the flat communication portion 10 are provided, the opening of the nozzle channel 100 on the bonding surface Bb side is a square of 50 μm×50 μm.

[0252] The following Test 1 and Test 2 were performed using an inkjet recording apparatus equipped with an inkjet head including the nozzle plates 110 of Examples 1 to 3 and Comparative Example 1.

[0253] [Test 1. Emission angle test]

[0254] UV ink heated to a viscosity of 8 cP was ejected at a driving voltage that made the droplet velocity average about 6 m / s. At this time, the ejection angle, i.e., the angle between the nozzle center axis and the ejected liquid, was evaluated for 1,280 nozzles to be within ±several degrees.

[0255] [Test 2. Upper speed limit test]

[0256] At a driving frequency of 40kHz, the injection speed of the UV ink heated to a viscosity of 8cP is increased from 5m / s. Then, the nozzle opening N where injection defects occur is measured as the injection speed when more than 5 nozzles out of 100 nozzles occur. In addition, when the injection speed is above 9m / s, it is difficult to produce injection defects even if the injection speed is high. In addition, if the injection speed is 11m / s, it is further difficult to produce injection defects, so it is ideal. Therefore, as the stability of the curved liquid surface, less than 9m / s is evaluated as "C", more than 9m / s and less than 11m / s is evaluated as "B", and more than 11m / s is evaluated as "A".

[0257] The results of Experiment 1 and Experiment 2 are shown in Table 1.

[0258] [Table 1]

[0259] [Table 1]

[0260]

[0261] [evaluate]

[0262] Comparing Example 1 with Comparative Example 1, Example 1 has excellent meniscus stability and is less likely to cause injection defects. This is because Example 1 has a nozzle tapered portion 20A in which the center of the nozzle opening N is located at the symmetric center of the tapered surface 20aA.

[0263] In addition, when Example 1 is compared with Examples 2 and 3, Examples 2 and 3 have higher ejection angles and better ejection characteristics. This is because the nozzle straight portions 30B and 30C are formed in the nozzle channel 100 .

[0264] In addition, when comparing Example 2 with Example 3, Example 2 has excellent meniscus stability and is less likely to cause injection defects. This is because a step surface is formed on the tapered surface 20aB of the nozzle tapered portion 20B.

[0265] The present invention can be used for a method of manufacturing a nozzle plate capable of achieving both high density of nozzle openings and good injection characteristics.

[0266] Description of Reference Numerals

[0267] 2 Droplet discharge head

[0268] 10 Straight connection

[0269] 20 Nozzle cone

[0270] 30 Nozzle straight part

[0271] 100 Nozzle Flow Path

[0272] 110 Nozzle Plate

[0273] 305 Opening hole (first hole)

[0274] 306 Nozzle hole (second hole)

[0275] 307 Nozzle straight hole (third hole)

[0276] 308 nozzle mask layer

[0277] N Nozzle opening

[0278] B Single crystal silicon substrate

[0279] Ba discharge surface (second surface)

[0280] Bb bonding surface (first side)

Claims

1. A method for manufacturing a nozzle plate, which is a method for manufacturing a nozzle plate for a droplet ejection head, wherein: Include: Step 1, forming a first hole and a second hole, wherein the first hole is connected to a first surface of a single crystal silicon substrate whose surface crystal orientation is a {100} plane and is longer in the [100] direction than in the [010] direction, and the second hole is capable of connecting the first hole and the second surface of the single crystal silicon substrate; and In the second step, the first hole and the second hole are enlarged by anisotropic wet etching on the single crystal silicon substrate to form a nozzle flow path, wherein the nozzle flow path includes a nozzle tapered portion having a {111} surface and a straight connecting portion continuous with the nozzle tapered portion.

2. The method for manufacturing a nozzle plate according to claim 1, wherein: In the first step, the length of the second hole in the [001] direction is formed to be substantially equal to the length from the end of the second hole on the first surface side to the end of the first hole in the [100] direction.

3. The method for manufacturing a nozzle plate according to claim 1, wherein: In the first step, the length of the second hole in the [001] direction is formed to be longer than the length from the end of the second hole on the first surface side to the end of the first hole in the [100] direction. A stepped surface is formed on the tapered portion of the nozzle.

4. The method for manufacturing a nozzle plate according to any one of claims 1 to 3, wherein: The centers of the first hole and the second hole coincide with each other.

5. The method for manufacturing a nozzle plate according to any one of claims 1 to 3, wherein: In the first step, the bottom of the first hole is formed in a stepped shape.

6. The method for manufacturing a nozzle plate according to any one of claims 1 to 3, wherein: The first step includes the following steps: The single crystal silicon substrate is deep-drilled from the first surface to the middle by dry etching to form a third hole, Next, a nozzle mask layer is formed along the inner surface of the third hole. Next, the nozzle mask layer formed at the bottom of the third hole is removed. The first hole is formed by further digging the third hole. The second step forms a nozzle flow path including a nozzle straight portion that is continuous from the end of the nozzle tapered portion on the second surface side.

7. The method for manufacturing a nozzle plate according to any one of claims 1 to 3, wherein: The single crystal silicon substrate has a non-wet etching layer formed on the second surface.

8. The method for manufacturing a nozzle plate according to any one of claims 1 to 3, wherein: The method includes a third step of increasing the diameter of the opening on the first surface side and / or the second surface side of the nozzle flow path.

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