Nozzle plate, droplet discharge head, droplet discharge apparatus, and method for manufacturing nozzle plate

Abstract

A nozzle plate (110) has a plurality of nozzle flow paths (111) in which nozzle opening portions (N) for discharging liquid droplets are formed on a first face (Ba) of a single-crystal silicon substrate (B), wherein the nozzle flow path (111) has: a nozzle tapered portion (1112) in which, as it goes from the first face (Ba) toward a second face (Bb) opposite the first face (Ba), the cross-sectional area orthogonal to the direction of discharge of the liquid droplets, that is, the flow path area, gradually widens; and a flat communication portion (1113) continuous with the end portion of the second face (Bb) side of the nozzle tapered portion (1112), in which the pair of opposite faces are substantially parallel, the length of the edge of the pair of opposite faces in which the faces constituting the flat communication portion (1113) intersect the edge of the second face (Bb) is longer than the length of the edge of the other face, and the nozzle tapered portion (1112) includes four faces in which the crystal faces are substantially {111}.

Description

Technical Field

[0001] This invention relates to a nozzle plate, a droplet discharge head, a droplet discharge device, and a method for manufacturing the nozzle plate. Background Technology

[0002] Conventionally, a method for manufacturing the nozzle plate of the droplet discharge head of a droplet discharge device is known to involve forming the nozzle flow path by anisotropic wet etching of a single-crystal silicon substrate (for example, see Patent Document 1).

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

[0004] However, when performing anisotropic wet etching on a monocrystalline silicon substrate with a {100} crystal orientation, the etching process proceeds in a fixed direction. Therefore, only nozzle flow paths with a square opening on the surface facing the droplet discharge can be formed. If such a nozzle plate is joined with another plate whose ink flow path cross-sectional shape is, for example, rectangular, the inconsistency in the shape of the joint between the ink flow path and the nozzle flow path leads to increased resistance during ink ejection. This necessitates an increase in driving voltage, or causes instability in the meniscus leading to ejection defects, thus deteriorating ejection characteristics. Furthermore, if the opening on the surface facing the droplet discharge is square, the number of nozzle flow paths provided on the monocrystalline silicon substrate decreases. Summary of the Invention

[0005] The present invention was made in view of this situation, and its object is to provide a nozzle plate, a droplet discharge head, a droplet discharge device, and a method for manufacturing a nozzle plate that can achieve both high density of the nozzle opening and optimal injection characteristics.

[0006] To address the aforementioned issues, the invention described in technical solution 1 is a nozzle plate comprising a plurality of nozzle flow paths having nozzle openings for discharging droplets formed on a first surface of a single-crystal silicon substrate. Each nozzle flow path comprises: a nozzle cone portion whose cross-sectional area, i.e., the flow path area, orthogonal to the droplet discharge direction gradually widens from the first surface toward a second surface opposite to the first surface; and a straight connecting portion continuous with the end of the nozzle cone portion on the second surface side, wherein a set of opposing surfaces of the straight connecting portion is substantially parallel, and the length of the side of the opposing set of surfaces intersecting the second surface of the straight connecting portion is longer than the length of the side of the other surfaces. The nozzle cone portion includes four surfaces with approximately {111} crystal planes.

[0007] In addition, to solve the above-mentioned problem, the invention described in technical solution 2 is a nozzle plate having a plurality of nozzle flow paths having nozzle openings for discharging droplets formed on a first surface of a single-crystal silicon substrate. The nozzle flow path includes: a nozzle cone portion, the cross-sectional area, i.e., the flow path area, which gradually widens from the first surface toward a second surface opposite to the first surface and is orthogonal to the discharge direction of the droplets; and a straight connecting portion, which is continuous with the end of the nozzle cone portion on the second surface side, and the set of opposing surfaces of the straight connecting portion is substantially parallel. The length of the side of the set of opposing surfaces among the sides where the surface constituting the straight connecting portion intersects with the second surface is longer than the length of the side of the other surface. The nozzle cone portion is composed of four surfaces with a crystal plane that is approximately {111}.

[0008] Furthermore, in the invention described in technical solution 3, in the nozzle plate described in technical solution 1 or 2, the crystal plane of the face in which the length of the side of the opposite set of faces intersects with the second face is longer than the length of the side of the other face is composed of approximately {101} planes.

[0009] Furthermore, in the invention described in technical solution 4, in the nozzle plate described in technical solution 1 or 2, the crystal plane of the face in which the length of the side of the opposite set of faces intersects with the second face is longer than the length of the side of the other face is composed of approximately {100} planes.

[0010] Furthermore, the invention described in technical solution 5 is that in the nozzle plate described in any one of technical solutions 1 to 4, at least a portion between the portion where the nozzle cone portion intersects with the straight connecting portion and the first surface is provided with a sidewall mask layer.

[0011] In addition, to solve the above-mentioned problems, the invention described in technical solution 6 is a nozzle plate having a plurality of nozzle flow paths having nozzle openings for discharging droplets formed on a first surface of a single-crystal silicon substrate. The nozzle flow paths include: a nozzle cone portion, the cross-sectional area, i.e., the flow path area, which gradually widens from the first surface toward a second surface opposite to the first surface and is orthogonal to the discharge direction of the droplets; and a straight connecting portion, which is continuous with the end of the nozzle cone portion on the second surface side and is provided to the second surface. At least a portion of the distance from the intersection of the nozzle cone portion and the straight connecting portion to the first surface has a sidewall mask layer. The nozzle cone portion includes four surfaces with approximately {111} crystal planes.

[0012] In addition, to solve the above-mentioned problems, the invention described in technical solution 7 is a nozzle plate having a plurality of nozzle flow paths having nozzle openings for discharging droplets formed on a first surface of a single-crystal silicon substrate. The nozzle flow path includes: a nozzle cone portion, the cross-sectional area orthogonal to the discharge direction of the droplets, i.e., the flow path area, gradually widens from the first surface toward a second surface opposite to the first surface; and a straight connecting portion, which is continuous with the end of the nozzle cone portion on the second surface side and is provided to the second surface. At least a portion between the portion where the nozzle cone portion intersects with the straight connecting portion and the first surface has a sidewall mask layer. The nozzle cone portion is composed of four surfaces with approximately {111} crystal planes.

[0013] Furthermore, the invention described in technical solution 8 is a nozzle plate described in any one of technical solutions 5 to 7, wherein the sidewall mask layer has a shape that gradually narrows from the first surface toward the second surface or from the second surface toward the first surface.

[0014] Furthermore, the invention described in technical solution 9 is a nozzle plate described in any one of technical solutions 1 to 8, wherein the nozzle flow path has a nozzle straight portion that is continuous with the end of the first surface side of the nozzle cone portion.

[0015] Furthermore, the invention described in technical solution 10 is that, in the nozzle plate described in technical solution 9, the maximum part of the flow path area of ​​the straight part of the nozzle is less than or equal to the flow path area of ​​the end of the first surface side of the conical part of the nozzle.

[0016] Furthermore, the invention described in technical solution 11 is that in the nozzle plate described in any one of technical solutions 1 to 10, the maximum length of the cone height from the first surface to the end of the second surface side of the nozzle cone portion is 20 μm or more.

[0017] In addition, the invention described in technical solution 12 is a droplet discharge head mounted on a droplet discharge device, wherein it includes a nozzle plate as described in any one of technical solutions 1 to 11.

[0018] In addition, the invention described in technical solution 13 is a droplet discharge device, wherein it includes the droplet discharge head described in technical solution 12.

[0019] Furthermore, the invention described in technical solution 14 is a method for manufacturing a nozzle plate for a droplet discharge head, comprising: a first step of forming a surface mask layer on a first surface of a monocrystalline silicon substrate with a {100} crystal orientation; a second step of forming a slit pattern in the surface mask layer; a third step of forming the slit by performing through-processing of the monocrystalline silicon substrate located below the slit pattern from the surface using dry etching or by performing deep-cutting processing from the surface using dry etching to the middle; and a fourth step... In the fifth step, a sidewall mask layer is formed in the aforementioned slit; in the sixth step, a circular or polygonal opening pattern is formed in the aforementioned surface mask layer to form a nozzle opening; in the seventh step, a through hole is formed by dry etching of the aforementioned monocrystalline silicon substrate located below the aforementioned opening pattern from the surface; and in the eighth step, a nozzle cone portion and a straight connecting portion continuous with the end of the nozzle cone portion facing the aforementioned first surface are formed by enlarging the aforementioned through hole using anisotropic wet etching of the aforementioned monocrystalline silicon substrate.

[0020] Furthermore, the invention described in technical solution 15 is performed between the fifth and sixth steps in the nozzle plate manufacturing method described in technical solution 14: the eighth step is to form a nozzle straight portion by dry etching the single crystal silicon substrate located below the opening pattern from the surface to the middle; and the ninth step is to form a nozzle mask layer along the inner surface of the nozzle straight portion.

[0021] Furthermore, the invention described in technical solution 16 is a method for manufacturing a nozzle plate for a droplet discharge head, comprising: a first step of forming a surface mask layer on a first surface of a monocrystalline silicon substrate with a crystal orientation of {100}; a second step of simultaneously forming a circular or polygonal opening pattern that forms a nozzle opening and a slit pattern that forms a slit on the surface mask layer; a third step of forming a slit by performing a through-processing process from the surface of the monocrystalline silicon substrate located below the slit pattern using dry etching or by performing a deep-cutting process from the surface to the middle using dry etching; a fourth step of forming a sidewall mask layer on the slit; a fifth step of forming a through-hole by performing a through-processing process from the surface of the monocrystalline silicon substrate located below the opening pattern using dry etching; and a sixth step of expanding the through-hole using anisotropic wet etching of the monocrystalline silicon substrate to form a nozzle cone portion and a straight connecting portion continuous with the end of the nozzle cone portion facing the second surface of the first surface.

[0022] Furthermore, the invention described in technical solution 17 is performed between the third and fifth steps in the nozzle plate manufacturing method described in technical solution 16: a seventh step is to form a nozzle straight portion by dry etching the single crystal silicon substrate located below the opening pattern from the surface to the middle; and an eighth step is to form a nozzle mask layer along the inner surface of the nozzle straight portion.

[0023] According to the nozzle plate, droplet discharge head, droplet discharge device, and nozzle plate manufacturing method of the present invention, both high density of nozzle opening and optimal injection characteristics can be achieved. Attached Figure Description

[0024] Figure 1 This is a schematic perspective view of the droplet discharge device of this embodiment.

[0025] Figure 2 This is an exploded perspective view showing the main parts of the droplet discharge head of this embodiment.

[0026] Figure 3A This is an enlarged top view of the nozzle plate showing the nozzle flow path of this embodiment.

[0027] Figure 3B Based on Figure 3A A cross-sectional view of the nozzle plate of line IIIB-IIIB.

[0028] Figure 4 This is a cross-sectional view of the nozzle plate in a modified example.

[0029] Figure 5A This is an enlarged top view of the nozzle plate showing the nozzle flow path of another embodiment.

[0030] Figure 5B This is an enlarged top view of the nozzle plate showing the nozzle flow path of another embodiment.

[0031] Figure 5C This is an enlarged top view of the nozzle plate showing the nozzle flow path of another embodiment.

[0032] Figure 6 This is a cross-sectional view of a nozzle plate showing the nozzle flow path in another embodiment.

[0033] Figure 7 This is a cross-sectional view of a nozzle plate showing the nozzle flow path in another embodiment.

[0034] Figure 8 This is a cross-sectional view of the nozzle plate showing the main steps of the nozzle plate manufacturing method according to the first embodiment.

[0035] Figure 9This is a cross-sectional view of the nozzle plate showing the main steps of the nozzle plate manufacturing method according to the second embodiment.

[0036] Figure 10 This is a cross-sectional view of the nozzle plate showing the main steps of the nozzle plate manufacturing method according to the third embodiment.

[0037] Figure 11 This is a cross-sectional view of a nozzle plate, showing a modified example of the main steps of the nozzle plate manufacturing method according to the third embodiment.

[0038] Figure 12 This is a cross-sectional view of a nozzle plate, showing a modified example of the main steps of the nozzle plate manufacturing method according to the third embodiment.

[0039] Figure 13 This is a cross-sectional view of a nozzle plate showing the manufacturing process of a modified nozzle plate.

[0040] Figure 14 This is a cross-sectional view of a nozzle plate showing the manufacturing process of a modified nozzle plate.

[0041] Figure 15 This is an enlarged top view showing an ink flow path of a piezoelectric plate.

[0042] Figure 16A This is an enlarged top view showing the nozzle flow path of the nozzle plate in the comparative example.

[0043] Figure 16B It is a cross-sectional view of the inkjet head with the nozzle plate of the comparative example attached, on a plane perpendicular to the front-to-back direction.

[0044] Figure 17A This is an enlarged top view showing the nozzle flow path of the nozzle plate in the comparative example.

[0045] Figure 17B It is a cross-sectional view of the inkjet head with the nozzle plate of the comparative example attached, on a plane perpendicular to the front-to-back direction.

[0046] Figure 17C It is a cross-sectional view of the inkjet head with the nozzle plate of the comparative example attached, perpendicular to the left-right direction.

[0047] Figure 18A This is an enlarged top view showing the nozzle flow path of the nozzle plate in the comparative example.

[0048] Figure 18B It is a cross-sectional view of the inkjet head with the nozzle plate of the comparative example attached, on a plane perpendicular to the front-to-back direction.

[0049] Figure 18C It is a cross-sectional view of the inkjet head with the nozzle plate of the comparative example attached, perpendicular to the left-right direction. Detailed Implementation

[0050] Hereinafter, 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 examples shown in the drawings. Furthermore, in the following description, parts having the same function and structure are labeled with the same reference numerals, and their descriptions are omitted.

[0051] [Inkjet recording device]

[0052] First, as a droplet ejection device in this embodiment, a structural example of an inkjet recording device 1 having an inkjet head 10 as a droplet ejection head is disclosed.

[0053] In the following description, as shown in the figures, the transport direction of the recording medium P in the inkjet recording apparatus 1 is defined as the front-to-back direction, the direction orthogonal to this transport direction in the transport surface of the recording medium P is defined as the left-to-right direction, and the direction perpendicular to both the front-to-back and left-to-right directions (the ink ejection direction) is defined as the up-down direction. Furthermore, the inkjet head 10 will also be described with its mounted position in the inkjet recording apparatus 1 as the reference direction.

[0054] Figure 1 This is a schematic perspective view of the inkjet recording apparatus 1 according to this embodiment. The inkjet recording apparatus 1, for example, transports a recording medium P, such as paper, through multiple units U in a back-and-forth direction via a transport section T equipped with a conveyor belt T1 and a transport roller T2. Multiple inkjet heads 10 are arranged in each unit U, and ink of various colors is ejected from each inkjet head 10 to print on the recording medium P.

[0055] [Inkjet head]

[0056] Figure 2 This is an exploded perspective view showing the main structure of an inkjet head 10. Specifically, in Figure 2 The diagram shows a head chip 100 having a nozzle plate 110, a flow path plate 120, a piezoelectric plate 130, and a wiring board 140. Additionally, in... Figure 2 The image shows an FPC200 (Flexible Printed Circuit). The FPC200 is electrically connected to the wiring board 140.

[0057] In addition, Figure 2 In the image, the nozzle opening N is depicted as being at the top, i.e., with... Figure 1 Reverse the top and bottom.

[0058] [Head Chip]

[0059] like Figure 2 As shown, the head chip 100 has a structure in which various plates are stacked.

[0060] Nozzle plate 110, flow path plate 120, piezoelectric plate 130 and wiring plate 140 are all plate-shaped components that are relatively long in the left-right direction and are roughly quadrangular prisms.

[0061] (Nozzle plate)

[0062] The nozzle plate 110 is configured with a through hole in the vertical direction, i.e., the nozzle flow path 111 (see reference). Figure 3A A substrate formed in rows along the left-right direction.

[0063] An opening, or nozzle opening N, for the nozzle flow path 111 is provided on the lower surface of the nozzle plate 110. That is, the lower surface of the nozzle plate 110 becomes the discharge surface (first surface) Ba of the inkjet head 10. Moreover, ink is discharged from the nozzle opening N, which is approximately perpendicular to the discharge surface Ba.

[0064] Details regarding the nozzle plate 110 and the nozzle flow path 111 will be described later.

[0065] (flow circuit board)

[0066] The flow path plate 120 is a rectangular plate-shaped component that is roughly the same as the nozzle plate 110 when viewed from above.

[0067] The flow path plate 120 is provided with a through flow path 121 and an independent discharge flow path 122.

[0068] The through flow path 121 is a flow path that communicates with the nozzle flow path 111. In addition, the independent discharge flow path 122 is a flow path that branches off from the through flow path 121.

[0069] The surface of nozzle plate 110 opposite to the discharge surface Ba, i.e., the bonding surface (second surface) Bb (refer to) Figure 3A The piezoelectric plate 130 is bonded (fixed) to the lower side of the flow path plate 120 via adhesive. Additionally, the lower surface of the piezoelectric plate 130 is bonded (fixed) to the upper side of the flow path plate 120 via adhesive.

[0070] The flow path board 120 is, for example, made of a silicon substrate.

[0071] (Piezoelectric plate)

[0072] The piezoelectric plate 130 is a rectangular plate-shaped component that is roughly the same as the nozzle plate 110 when viewed from above.

[0073] The piezoelectric plate 130 is provided with a pressure chamber 131, a common discharge flow path 132, and a vertical discharge flow path 133.

[0074] Pressure chamber 131 is connected to through flow path 121. Additionally, common discharge flow path 132 is connected to independent discharge flow path 122. Furthermore, vertical discharge flow path 133 is connected to common discharge flow path 132.

[0075] The piezoelectric plate 130 is made of ceramic piezoelectric material (a component that deforms according to the application of voltage). Examples of such piezoelectric materials include PZT (lead zirconate titanate), lithium niobate, barium titanate, lead titanate, and lead metaniobate.

[0076] (Wiring board)

[0077] Wiring board 140 is a flat substrate with an area larger than that of piezoelectric plate 130.

[0078] The wiring board 140 is provided with an ink supply path 141 and an outlet hole 142.

[0079] The ink supply path 141 communicates with an ink chamber (not shown) via an opening 1411 on the upper surface. Additionally, the ink supply path 141 communicates with a pressure chamber 131 via a second opening 1412 on the lower surface. Furthermore, the discharge port 142 communicates with a vertical discharge path 133.

[0080] The lower side of the wiring board 140 is bonded to the upper side of the piezoelectric plate 130 by an adhesive.

[0081] As a wiring board 140, substrates such as glass, ceramic, silicon, and plastic can be used.

[0082] Multiple wires are provided on the bonding surface of the wiring board 140 to the piezoelectric plate 130, which are respectively connected to the electrodes of the ink channel described later. In addition, the FPC 200 is connected to the end of the wiring board 140 where the wires are provided, for example, via an ACF (Anisotropic Conductive Film).

[0083] The drive signal output from the drive circuit (not shown) is supplied to the electrodes of the ink channel via the wiring 210 on the FPC200 and the wiring of the wiring board 140.

[0084] {Ink Channel}

[0085] With the flow path plate 120, piezoelectric plate 130, and wiring board 140 joined together, the through flow path 121, pressure chamber 131, and ink supply flow path 141 are connected as a single unit to form an ink channel. The ink channel is positioned to overlap with the nozzle flow path 111 when viewed from above and below, and is connected to the nozzle flow path 111. Thus, the ink channel and the nozzle flow path 111 each constitute an ink flow path.

[0086] Electrodes (not shown) are formed on the inner wall surface of the ink channels. Based on the potential difference of the drive signal applied to the electrodes of adjacent ink channels, the portion of the wall surface between the ink channels composed of the piezoelectric element of the piezoelectric plate 130 is displaced. This repeated shear-mode displacement of the wall surface causes fluctuations in the pressure of the ink within the ink channels. Furthermore, the volume of the pressure chamber 131 changes according to these pressure fluctuations, and ink is discharged from the nozzle opening N. In other words, the inkjet head 10 of this embodiment performs shear-mode ink discharge.

[0087] {Ink Discharge Path}

[0088] Furthermore, an ink discharge path is formed by an independent discharge path 122, a shared discharge path 132, a vertical discharge path 133, and a discharge hole 142. A portion of the ink supplied from the ink chamber to the ink channel can be discharged to the outside of the inkjet head 10 via this ink discharge path. This allows air bubbles and foreign matter within the ink channel to be discharged along with the ink to the outside of the printhead chip 100.

[0089] Furthermore, in the inkjet head 10 of the present invention, the flow path plate 120 is not a necessary structure. That is, it can also be a structure in which the nozzle plate 110 and the piezoelectric plate 130 are directly bonded together.

[0090] Furthermore, as described above, the openings of the ink flow paths in the bonding surfaces of each plate of the head chip 100 are preferably similar in shape to each other, and even more preferably the same in shape.

[0091] In addition, Figure 2 The diagram shows a single column of nozzle plates 110 arranged in the left-right direction for the nozzle openings N, but this is not a limitation. That is, multiple columns of nozzle openings N can also be arranged in the front-back direction.

[0092] [Nozzle Plate]

[0093] Figure 3A This is an enlarged top view of a nozzle flow path 111 when viewed from the adhesive surface Bb side of the nozzle plate 110. Figure 3B It means based on Figure 3A A cross-sectional view of a nozzle flow path 111 of line IIIB-IIIB.

[0094] The nozzle plate 110 is made of a single-crystal silicon substrate B.

[0095] (Single-crystal silicon substrate)

[0096] The monocrystalline silicon substrate B is a plate-shaped component made of monocrystalline silicon (Si) with a thickness of approximately 100 μm to 725 μm. By using the monocrystalline silicon substrate B as the substrate of the nozzle plate 110, the nozzle flow path 111 can be processed with high precision during the manufacturing process. Therefore, a nozzle flow path 111 with less positional error and shape deviation can be formed.

[0097] (Nozzle flow path)

[0098] Nozzle flow path 111 is a through-hole that extends from the discharge surface Ba of the single-crystal silicon substrate B to the bonding surface Bb. For example... Figure 3B As shown, from the discharge surface Ba toward the bonding surface Bb, it includes, for example, a nozzle opening N, a nozzle straight portion 1111, a nozzle conical portion 1112, and a straight connecting portion 1113.

[0099] <Nozzle opening>

[0100] The nozzle opening N is a circular or polygonal hole. The nozzle opening N is arranged in a matrix on the discharge surface Ba side of the single crystal silicon substrate B, and the bonding surface Bb side is connected to the nozzle straight section 1111.

[0101] For example, when the shape of the nozzle opening N is circular, its diameter can be around 15μm to 45μm.

[0102] <Nose Straight Section>

[0103] like Figure 3B As shown, the straight portion 1111 of the nozzle and the end of the discharge surface Ba side of the conical portion 1112 of the nozzle are continuously formed.

[0104] If a nozzle straight section 1111 is provided, the resistance applied when ink is ejected from the nozzle opening N increases, the vibration of the meniscus is suppressed, and thus the shape of the meniscus becomes more stable.

[0105] In addition, Figure 3B The example shown is a direction orthogonal to the ink discharge direction in the straight section 1111 of the nozzle. Figure 3B The cross-sectional area (in the left and right directions) of the flow path is roughly constant in the vertical direction, but it is not limited to this.

[0106] For example, the angle between the straight portion 1111 of the nozzle and the axis parallel to the central axis of the nozzle is not limited to 0°; as long as this angle is less than 15°, it can also be conical. Alternatively, it can be as follows... Figure 4As shown, the nozzle straight section 1111 has multiple surfaces 1111a and 1111b that form different angles with the axis parallel to the nozzle center axis. However, from the viewpoint of further improving the stability of the meniscus, it is preferable that the maximum flow path area of ​​the nozzle straight section 1111 is less than or equal to the flow path area of ​​the end of the nozzle cone section 1112 on the discharge surface Ba side.

[0107] Furthermore, the vertical length (height of the nozzle straight portion 1111) is preferably about 5 μm to 50 μm. By keeping the height of the nozzle straight portion 1111 within this range, appropriate resistance is applied when ejecting ink.

[0108] <Nose Conical Section>

[0109] The nozzle cone portion 1112 includes four surfaces with {111} crystal planes. It has a cone shape in which the flow path area gradually widens from the discharge surface Ba towards the bonding surface Bb, and the angle between the cone and the axis parallel to the nozzle central axis is approximately constant at 15° or more. By providing the nozzle cone portion 1112 in the nozzle flow path 111, the shape of the meniscus and the ink ejection can be stabilized even when the ink meniscus retracts into the depth of the nozzle flow path 111 due to high-speed driving.

[0110] In the nozzle flow path 111, it is preferable to have at least one Figure 3B The portion shown, from the discharge surface Ba to the end of the adhesive surface Bb side of the nozzle cone 1112, that is, the cone height h, is 20 μm or more, i.e., the maximum length of the cone height h is 20 μm or more. By making the maximum length of the cone height h 20 μm or more, the effect of stabilizing the meniscus shape of the ink in the nozzle cone 1112 can be sufficiently obtained.

[0111] In addition, such as Figure 3B As shown, when the nozzle flow path 111 has a nozzle straight section 1111, the cone height h includes the height of the nozzle straight section 1111.

[0112] Furthermore, the nozzle cone portion 1112 only needs to include four surfaces with the {111} crystal plane. For example, the nozzle cone portion 1112 may also include other surfaces that are different from the {111} crystal plane and have different angles with the axis parallel to the nozzle central axis.

[0113] On the other hand, the nozzle cone portion 1112 may also be composed of only four surfaces with {111} crystal planes. Specifically, when the connection between the nozzle cone portion 1112 and the straight connecting portion 1113 has a surface (platform plane) that is approximately parallel to the discharge surface Ba, it is possible to simultaneously satisfy the structure of the nozzle cone portion 1112 composed of only four surfaces with {111} crystal planes and the structure of the straight connecting portion 1113 described later.

[0114] <Straight Connecting Part>

[0115] The straight connecting part 1113 is continuous with the end of the adhesive surface Bb side of the nozzle conical part 1112 and is provided to the adhesive surface Bb.

[0116] like Figure 3A As shown, the opposing sets of faces of the straight connecting portion 1113 are approximately parallel. Furthermore, the length of the side of the opposing set of faces, which forms the intersection of the face constituting the straight connecting portion 1113 and the adhesive surface Bb, is longer than the length of the side of the other faces. Moreover, the opening in the adhesive surface Bb is elongated in shape.

[0117] By making the cross-sectional shape of the surface of the straight connecting portion 1113 perpendicular to the vertical direction elongated, the density of the nozzle opening portion N in the nozzle plate 110 can be further increased.

[0118] (Sidewall mask layer)

[0119] The sidewall mask layer 112 will seal the through hole (slit S described later) formed adjacent to the nozzle flow path 111 during the nozzle flow path 111 formation process described later. Furthermore, it serves to prevent ink from flowing out of the through hole when the nozzle plate 110 is in use.

[0120] like Figure 3B As shown, the sidewall mask layer 112 is provided along the inner surface of the straight connecting portion 1113 at the portion where the nozzle cone portion 1112 intersects with the straight connecting portion 1113.

[0121] There are no particular limitations on the material used to form the sidewall mask layer 112. For example, oxides such as SiO2 (silicon oxide), metal plating based on Al (aluminum), Cr (chromium), or resin can be used.

[0122] Furthermore, the width of the sidewall mask layer 112 is preferably 0.1 μm to 50 μm. More particularly preferably, the width of the sidewall mask layer 112 is 0.5 μm to 20 μm. If the width of the sidewall mask layer 112 is 0.5 μm or more, the effect of stopping the anisotropic wet etching (WE) process is improved during the formation process of the straight connecting portion 1113 described later. Additionally, if the width of the sidewall mask layer 112 is 20 μm or less, its formation becomes easier.

[0123] In particular, when the sidewall mask layer 112 is made of oxide, its width is preferably 0.5 μm to 5 μm. This is because if the width of the sidewall mask layer 112 is 5 μm or less, it is possible to form it using a thermal oxidation method in a short time and at low cost.

[0124] Furthermore, as the sidewall mask layer 112, it is preferably as follows: Figure 3B As shown, the width of the front end is formed to gradually narrow from one of the discharge surface Ba and the adhesive surface Bb to the other. Specifically, it is preferable that the width of the front end on one side is more than 20% thinner than the width of the front end on the other side.

[0125] By shaping the sidewall mask layer 112 in this way, it is easy to embed the sidewall mask layer 112 without gaps during the formation process of the sidewall mask layer 112 described later.

[0126] Furthermore, it is preferable that when the cross-sectional shape of the surface perpendicular to the vertical direction of the straight connecting portion 1113 is elongated, the crystal plane of the face whose length is longer than the length of the side of the opposite set of faces among the edges where the surface constituting the straight connecting portion 1113 intersects the bonding surface Bb is as follows: Figure 3A As shown, it is composed of approximately {101} planes of a single-crystal silicon substrate B, or as... Figure 5A As shown, it is composed of approximately {100} planes of a single-crystal silicon substrate B.

[0127] If this structure is adopted, then as follows Figure 3A as well as Figure 5A As shown, the nozzle cone 1112 is symmetrical from left to right. As a result, the symmetry of ink flow in the nozzle flow path 111 is maintained, making the injection angle more stable.

[0128] Furthermore, the flat connecting portion 1113 is not limited to a structure in which the crystal plane is formed by approximately {101} or approximately {100} planes of the monocrystalline silicon substrate B.

[0129] In addition, Figure 3A The diagram illustrates a set of approximately {101} parallel opposing surfaces of the straight connecting portion 1113. The cross-sectional shape of the surface of the straight connecting portion 1113 perpendicular to the vertical direction is elongated, but not limited to this. For example, it could also be as follows... Figure 5B As shown, the opposing surfaces are not approximately parallel, and the cross-sectional shape of the surface of the straight connecting portion 1113 perpendicular to the vertical direction is circular. Alternatively, it can be as follows: Figure 5C As shown, the opposing surfaces are made to be approximately parallel to each other, and the cross-sectional shape of the surface of the straight connecting part 1113 that is perpendicular to the vertical direction is rectangular.

[0130] Alternatively, it can be like Figure 6As shown, the sidewall mask layer 112 adjacent to the straight connecting portion 1113 is removed from the nozzle plate 110. If at least a portion of the sidewall mask layer 112 remains between the portion where the nozzle cone portion 1112 intersects with the straight connecting portion 1113 and the discharge surface Ba, ink leakage can be suppressed.

[0131] In addition, Figure 3B as well as Figure 4 The diagram illustrates a case where the sidewall mask layer 112 is formed to penetrate the monocrystalline silicon substrate B, but it is not limited to this case.

[0132] In addition, Figure 3A and Figures 5A to 5C The illustration shows a case where the nozzle opening N is approximately square, but it is not limited to this. When the nozzle flow path 111 has a nozzle straight section 1111, the nozzle opening N can also be any shape such as circular or polygonal.

[0133] In addition, such as Figure 7 As shown, the nozzle flow path 111 may include at least a nozzle opening portion N, a nozzle cone portion 1112, and a straight connecting portion 1113.

[0134] In addition, the above example illustrates a nozzle plate 110 installed on the inkjet head 10 and discharging ink, but the liquid discharged from the nozzle plate 110 is not limited to ink.

[0135] [The effects of the invention]

[0136] As shown above, the nozzle plate 110 of this embodiment has a plurality of nozzle flow paths 111 on a first surface Ba of a single-crystal silicon substrate B, wherein nozzle openings N for discharging droplets are formed. The nozzle flow path 111 includes: a nozzle cone portion 1112, which gradually widens in cross-sectional area orthogonal to the discharge direction of the droplets, i.e., the flow path area, as it moves from the first surface Ba toward the second surface Bb opposite to the first surface Ba; and a straight connecting portion 1113, which is continuous with the end of the nozzle cone portion 1112 on the second surface Bb side, and the opposing set of surfaces is substantially parallel. The length of the side of the opposing set of surfaces in the side where the surface constituting the straight connecting portion 1113 intersects the second surface Bb is longer than the length of the side of the other surface. The nozzle cone portion 1112 includes four surfaces with a crystal plane that is approximately {111}.

[0137] According to this structure, the cross-sectional shape of the surface of the straight connecting portion 1113 perpendicular to the vertical direction is elongated, which can increase the density of the nozzle opening portion N in the nozzle plate 110. In addition, when it is joined with other plates having ink flow paths with a rectangular cross-sectional shape of the surface perpendicular to the vertical direction, the shape of the joint between the ink flow path and the nozzle flow path 111 is approximately the same, thus improving the injection characteristics.

[0138] In addition, the crystal planes of the opposite set of faces whose side lengths are longer than the side lengths of the other faces are composed of approximately {101} planes or approximately {100} planes.

[0139] According to this structure, the nozzle cone 1112 becomes symmetrical from left to right, maintaining the symmetry of the liquid flow, thus making the ejection angle more stable.

[0140] Furthermore, the nozzle plate 110 of this embodiment includes a plurality of nozzle flow paths 111 on a first surface Ba of a single-crystal silicon substrate B, wherein nozzle flow paths 111 include: a nozzle cone portion 1112, which gradually widens in cross-sectional area orthogonal to the discharge direction of the droplet from the first surface Ba toward a second surface Bb opposite to the first surface Ba; and a straight connecting portion 1113, which is continuous with the end of the nozzle cone portion 1112 on the second surface Bb and is provided to the second surface Bb, and has a sidewall mask layer 112 in at least a portion from the portion where the nozzle cone portion 1112 intersects with the straight connecting portion 1113 to the first surface Ba, and the nozzle cone portion 1112 includes four surfaces with a crystal plane that is approximately {111}.

[0141] According to this structure, the through hole formed adjacent to the nozzle flow path 111 can be blocked to prevent liquid from flowing out of the through hole.

[0142] In addition, the sidewall mask layer 112 has a shape that gradually narrows from the first surface Ba toward the second surface Bb or from the second surface Bb toward the first surface Ba.

[0143] According to this structure, the sidewall mask layer 112 can be easily embedded without gaps, thus further preventing liquid from flowing out from the through hole formed adjacent to the nozzle flow path 111.

[0144] In addition, the nozzle flow path 111 has a nozzle straight section 1111 that is continuous with the end of the first surface side Ba of the nozzle cone section 1112.

[0145] According to this structure, the resistance during droplet ejection increases, which can suppress the vibration of the meniscus and make the shape of the meniscus more stable, thereby improving the ejection stability.

[0146] Furthermore, the maximum flow area of ​​the nozzle straight portion 1111 is less than or equal to the flow area of ​​the end of the nozzle conical portion 1112 on the first surface Ba side.

[0147] According to this structure, the effect of improving the stability of the curved surface caused by the nozzle straight section 1111 can be further enhanced.

[0148] In addition, the maximum length of the cone height h from the first surface Ba to the end of the second surface side Bb of the nozzle cone portion 1112 is 20 μm or more.

[0149] According to this structure, the resistance during droplet ejection increases, which can suppress the vibration of the meniscus and make the shape of the meniscus more stable, thereby improving ejection stability.

[0150] [Manufacturing method of nozzle plate]

[0151] [First Implementation Method]

[0152] Next, based on Figure 8 The manufacturing method of the first embodiment of the nozzle plate 110 described above will be explained.

[0153] The method for manufacturing the nozzle plate in the first embodiment is a method for manufacturing the nozzle plate 110 of the droplet discharge head 10, including... Figure 8 The A-1 to A-7 processes are shown. Furthermore, a nozzle plate 110 is manufactured such that a nozzle flow path 111 is formed having at least a nozzle opening N, a nozzle cone 1112, and a straight connecting portion 1113.

[0154] (Process A-1)

[0155] First, as part of process A-1 (first process), a surface mask layer 113 is uniformly formed on the discharge surface (first surface) Ba of a single-crystal silicon substrate B with a crystal orientation of {100}.

[0156] <Surface Mask Layer>

[0157] As for the material used to form the surface mask layer 113, similar to the sidewall mask layer 112, materials such as SiO2, Al, Cr, or resin can be used.

[0158] As a method for forming the surface mask layer 113, for example, regarding the formation of a mask layer composed of SiO2, thermal oxidation and CVD (Chemical Vapor Deposition) methods can be applied. Thermal oxidation of SiO2 is preferred. This is because SiO2 has good adhesion to the single-crystal silicon substrate B, which helps prevent side etching during the anisotropic wet etching (WE) process described later.

[0159] In addition, the surface mask layer 113 can be Figure 8 The single-layer structure shown can also be a multi-layer structure.

[0160] (Process A-2)

[0161] Next, as step A-2 (second step), a slit pattern 115, which becomes the slit S described later, is formed on the surface mask layer 113.

[0162] Specifically, a resist pattern is first formed on the surface mask layer 113 using a known photolithography technique.

[0163] <Resist Pattern>

[0164] In forming the resist pattern, either a positive or negative photoresist can be used. Known materials can be used as both positive and negative photoresists. For example, ZPN-1150-90 manufactured by Zeon Corporation of Japan can be used as a negative photoresist. Additionally, OFPR-800LB and OEBR-CAP112PM manufactured by Tokyo Ohka Kogyo Co., Ltd. can be used as positive photoresists.

[0165] A resist layer is formed by coating to a specified thickness using a spin coater or similar equipment. Then, a pre-baking treatment is performed under conditions such as 110°C for 90 seconds.

[0166] To improve adhesion, HMDS (hexamethyldisilazane) treatment can be performed before resist coating. HMDS treatment can be performed using organic materials called hexamethyldisilazane, such as OAP (hexamethyldisilazane, manufactured by Tokyo Ohka Kogyo Co., Ltd.). Similar to resist coating, it can be applied using a spin coater, and improved adhesion can be expected even when exposed to hexamethyldisilazane vapor.

[0167] After the resist layer is formed, the resist layer is exposed using a prescribed mask and an aligner, etc. For example, in the case of contact aligner, the exposure is at approximately 50 mJ / cm. 2 The light intensity is then applied. Then, by immersing the photosensitive portion of the resist layer in a developer (for example, NMD-3 manufactured by Tokyo Ohka Kogyo Co., Ltd. for 60 to 90 seconds), the resist pattern is removed, thereby forming a resist pattern on the surface mask layer 113.

[0168] After the resist pattern is formed, the resist pattern is used as a mask to perform dry etching (DE1) on the surface mask layer 113, thereby forming the slit pattern 115. After the slit pattern 115 is formed, the resist pattern is removed.

[0169] <Dry Etching>

[0170] As for dry etching (DE1), it can be performed using RIE (Reactive Ion Etching) devices, or ICP (Inductively Coupled Plasma)-RIE etching devices that employ inductive coupling for the discharge method. Additionally, CHF3 (trifluoromethane) and CF4 (tetrafluoromethane) can be used as process gases.

[0171] As an example, using the RIE-100C dry etching apparatus manufactured by SUMCO Corporation, etching is performed for a specified time under the conditions of CHF3 gas flow rate of 80 sccm, pressure of 3 Pa, and RF power of 90 W, thereby forming a slit pattern 115.

[0172] <Removal of resist patterns>

[0173] In addition, as a method for removing resist patterns, wet processes using acetone or acid solutions and dry processes using oxygen plasma can be used for removal.

[0174] (Process A-3, Process A-4)

[0175] Next, as step A-3 (third step), the slit S is formed by dry etching (DE2) through the monocrystalline silicon substrate B located below the slit pattern 115 from the surface. Then, as step A-4 (fourth step), a sidewall mask layer 112 is formed in the slit S.

[0176] At this point, dry etching (DE2) can be performed using an ICP-RIE etching apparatus that employs inductively coupled plasma for the discharge mode.

[0177] <Bosch Craftsmanship>

[0178] In addition, by using Bosch's process, which employs SF6 (sulfur hexafluoride), C4F8 (cyclobutane octafluoride), O2 (oxygen) and other process gases, and repeatedly performs film formation and etching, high-precision and vertical slits S can be formed.

[0179] Furthermore, the slit S can also be formed such that the width of the cross-section of the surface perpendicular to the vertical direction is equal at any location. However, in this case, during the formation of the sidewall mask layer 112, the slit S is easily blocked by the mask near the front, potentially creating a gap on the inner side. Therefore, as... Figure 8As shown, if the slit S is formed to gradually narrow from one side of the monocrystalline silicon substrate B to the other, it is easy to form a gapless sidewall mask layer 112. Moreover, during the anisotropic wet etching (WE) process in step A-7 described later, a straight connecting portion 1113 with higher precision can be formed, which is therefore preferred.

[0180] In addition, as a method for forming the sidewall mask layer 112, a thermal oxidation method composed of SiO2 can be applied, for example.

[0181] (Process A-5)

[0182] Next, as step A-5 (the fifth step), a circular or polygonal opening pattern 114 is formed on the surface mask layer 113 to form the nozzle opening N.

[0183] The method for forming the opening pattern 114 is the same as the method for forming the slit pattern 115 in process A-2.

[0184] (Process A-6)

[0185] Next, as step A-6 (sixth step), through holes are formed by dry etching (DE2) on the monocrystalline silicon substrate B located below the opening pattern 114 from the surface.

[0186] (Process A-7)

[0187] Finally, as step A-7 (seventh step), the through hole is enlarged by anisotropic wet etching (WE). Furthermore, a nozzle cone portion 1112 and a straight connecting portion 1113 communicating with the nozzle cone portion 1112 are formed.

[0188] <Anisotropic Wet Etching>

[0189] In anisotropic wet etching (WE), alkaline aqueous solutions such as KOH (potassium hydroxide), TMAH (tetramethylammonium hydroxide), and EDP (ethylenediamine catechol) are used. In the single-crystal silicon substrate B, the nozzle cone 1112 becomes the {111} surface with an extremely slow etching rate. Therefore, the nozzle cone 1112 is formed at an angle of 35.3° to the axis parallel to the nozzle central axis.

[0190] Furthermore, as etching progresses and the nozzle cone portion 1112 forms to the point where it abuts against the sidewall mask layer 112, the sidewall mask layer 112 controls the progress of etching and suppresses the expansion of the nozzle flow path 111. Therefore, starting from the point where the surface F1 abuts against the sidewall mask layer 112, a straight connecting portion 1113 is formed along the inner surface F2 of the sidewall mask layer 112.

[0191] [The effects of the invention]

[0192] According to the above-described method for manufacturing the nozzle plate 110 of the first embodiment of the present invention, the expansion of the nozzle flow path 111 generated by the anisotropic wet etching (WE) of the single-crystal silicon substrate B can be controlled by the sidewall mask layer 112 formed in the slit S. That is, depending on the formation location of the slit S and the sidewall mask layer 112, the cross-sectional shape of the surface of the straight connecting portion 1113 perpendicular to the vertical direction can be arbitrary.

[0193] Therefore, for example, if the cross-sectional shape of the surface of the ink flow path of the flow path plate 120 perpendicular to the vertical direction is rectangular, then correspondingly, the length of a set of opposing surfaces in the side where the surface constituting the straight connecting portion 1113 intersects with the bonding surface (second surface) Bb is longer than the length of the side of the other surface to form a slit S and a sidewall mask layer 112, thereby enabling the opening on the bonding surface Bb side of the nozzle flow path 111 to be elongated.

[0194] Therefore, when bonded to other boards, it can prevent the deterioration of injection characteristics caused by the inconsistency in shape between the ink flow path of the other board and the nozzle flow path 111 of the nozzle plate 110. In addition, it can increase the density of the nozzle openings N in the nozzle plate 110.

[0195] [Second Implementation]

[0196] Next, based on Figure 9 The manufacturing method of the nozzle plate 110 according to the second embodiment will be described.

[0197] The manufacturing method of the nozzle plate 110 in the second embodiment includes: Figure 9 The steps B-1 to B-6 are shown. Furthermore, in the following description, details that overlap with the manufacturing steps of the nozzle plate in the first embodiment are omitted.

[0198] (Process B-1, Process B-2)

[0199] In step B-1 (first step), a surface mask layer 113 is uniformly formed on the surface of a single-crystal silicon substrate B with a crystal orientation of {100}. After step B-1, as step B-2 (second step), an opening pattern 114 and a slit pattern 115 are simultaneously formed on the surface mask layer 113.

[0200] The method of forming the opening pattern 114 and the slit pattern 115 is the same as that of process A-2 and process A-5.

[0201] In this B-2 process, by simultaneously patterning the nozzle opening N and the slit S, the positional relationship between the nozzle opening N and the slit S can be easily maintained.

[0202] (Process B-3)

[0203] Next, as step B-3 (the third step), slit S is formed. The method for forming slit S is the same as that for step A-3.

[0204] However, when performing dry etching (DE2) on the monocrystalline silicon substrate B below the slit pattern 115 from the surface, it is possible that the monocrystalline silicon substrate B below the opening pattern 114 may also be etched. Therefore, it is preferable to protect the opening pattern 114 in advance with a resist layer or the like, and remove the resist layer after the slit S is formed.

[0205] (Process B-4)

[0206] Next, as step B-4 (fourth step), a sidewall mask layer 112 is formed in the slit S. The material and formation method of the sidewall mask layer 112 are the same as those in step A-4.

[0207] Furthermore, when the sidewall mask layer 112 is formed, if a mask layer is also formed on the opening pattern 114, it is removed by etching using a RIE device or the like.

[0208] (Process B-5, Process B-6)

[0209] Next, similar to step A-6, as step B-5 (the fifth step), a through-hole is formed by dry etching (DE2) through the single-crystal silicon substrate B below the opening pattern 114. Furthermore, similar to step A-7, as step B-6 (the sixth step), anisotropic wet etching (WE) is performed on the through-hole to form a nozzle flow path 111, in which a straight connecting portion 1113 is formed along the inner surface F2 of the sidewall mask layer 112, starting from the nozzle opening N, the nozzle cone portion 1112, and the portion where the surface F1 abuts against the sidewall mask layer 112.

[0210] [The effects of the invention]

[0211] In the manufacturing method of the nozzle plate 110 of the second embodiment shown above, the opening pattern 114 and the slit pattern 115 are formed simultaneously in the B-2 process. Therefore, the nozzle opening N and the slit S are easily kept symmetrical, and a nozzle flow path 111 with a more stable ejection angle can be formed.

[0212] [Third Implementation Method]

[0213] Next, based on Figure 10 A method for manufacturing a nozzle plate according to a third embodiment of the present invention, and a nozzle plate manufactured therefrom, will be described.

[0214] The manufacturing method of the nozzle plate 110 in the third embodiment includes steps A-8 and A-9 between steps A-5 and A-6 in the manufacturing method of the nozzle plate 110 in the first embodiment. Therefore, detailed descriptions of steps A-1 to A-7 are omitted.

[0215] (Process A-8)

[0216] exist Figure 10 The main steps of the nozzle plate manufacturing method according to the third embodiment are shown in the figure.

[0217] After the opening pattern 114 is formed in process A-5, as process A-8 (eighth process), the single crystal silicon substrate B below the opening pattern 114 is dry etched from the surface (DE2) according to the predetermined length of the nozzle straight portion 1111, thereby forming the nozzle straight portion 1111.

[0218] (Process A-9)

[0219] Next, as step A-9 (ninth step), a nozzle mask layer 116 is formed along the inner surface of the nozzle straight portion 1111. The material and forming method of the nozzle mask layer 116 are the same as those of the surface mask layer 113 in step A-1.

[0220] Then, the nozzle mask layer 116 formed at the bottom of the nozzle straight portion 1111 is removed. The nozzle mask layer 116 at the bottom of the nozzle straight portion 1111 can be removed by etching using a RIE-based device or the like. At this time, the nozzle mask layer 116 on the sidewall of the nozzle straight portion 1111 is difficult to remove in dry etching, so the bottom nozzle mask layer 116 is etched first.

[0221] Furthermore, as a dry etching condition, low pressure and high bias are used, which makes it more difficult to etch the nozzle mask layer 116 on the sidewall.

[0222] (Process A-6, Process A-7)

[0223] Furthermore, steps A-6 and A-7 are performed in the same manner as in the first embodiment described above.

[0224] In process A-6, the monocrystalline silicon substrate B below the nozzle straight section 1111 is dry etched from the surface (DE2) to form a through hole.

[0225] In process A-7, the through-hole is enlarged by anisotropic wet etching (WE). At this time, the nozzle straight portion 1111 is protected by the nozzle mask layer 116 to suppress the progress of etching. Therefore, the nozzle straight portion 1111 is not etched and remains, forming a nozzle flow path 111 with the nozzle straight portion 1111.

[0226] [The effects of the invention]

[0227] According to the manufacturing method of the nozzle plate 110 of the third embodiment described above, the nozzle mask layer 116 formed in the nozzle flow path 111 suppresses the progress of etching during anisotropic wet etching (WE). Therefore, a nozzle straight portion 1111 of the desired length can be formed in the nozzle flow path 111.

[0228] Furthermore, in the third embodiment, in the A-8 process, dry etching (DE2) is performed by changing the processing conditions (e.g., time, power, pressure, gas flow rate, etc.), thereby enabling the provision of a nozzle straight section 1111 composed of multiple surfaces with different angles to axes parallel to the nozzle central axis.

[0229] In addition, in the third embodiment, the nozzle flow path 111 having the nozzle straight portion 1111 is formed by performing the A-8 and A-9 processes between the A-5 and A-6 processes, but it is not limited to this.

[0230] For example, it can also be like Figure 11 As shown, between steps B-4 and B-5, step B-7 (seventh step) is performed to form the nozzle straight portion 1111 by dry etching (DE2) according to the predetermined length of the nozzle straight portion 1111, and step B-8 (eighth step) is performed to form the nozzle mask layer 116 along the inner surface of the nozzle straight portion 1111, thereby forming a nozzle flow path 111 having the nozzle straight portion 1111.

[0231] Alternatively, at this time, it is also possible to do as follows: Figure 12 As shown, step B-7 is performed between steps B-3 and B-4. This allows the sidewall mask layer 112 and the nozzle mask layer 116 to be formed simultaneously in step B-4, simplifying step B-8.

[0232] In addition, if the shape of the slit S is negatively affected by the dry etching (DE2) in the B-7 process, the slit S can be thermally oxidized to a thickness of 0.1 μm after the B-3 process, and then the B-7 process can be performed.

[0233] Furthermore, in the embodiments described above, the slit S is formed by dry etching (DE2) through the monocrystalline silicon substrate B below the slit pattern 115, but is not limited to this. The slit S can also be an elongated hole formed by deep drilling to the middle.

[0234] Alternatively, the nozzle cone portion 1112 and the straight connecting portion 1113 can be formed by controlling the time on the side of the nozzle flow path 111 where the sidewall mask layer 112 is not formed, so that the anisotropic wet etching (WE) is stopped midway. Or, the anisotropic wet etching (WE) can continue until the end, thereby forming only the nozzle cone portion 1112.

[0235] Alternatively, the following process can be performed: after forming the straight connecting portion 1113 by anisotropic wet etching (WE), the mask layer including the sidewall mask layer 112 and the nozzle mask layer 116 in the nozzle flow path 111 is removed. For example, if the mask layer is formed of SiO2, it can be removed by hydrofluoric acid.

[0236] Furthermore, when the mask layer is removed, the portion of the sidewall mask layer 112 adjacent to the inner surface of the straight connecting portion 1113 is completely removed. However, the sidewall mask layer 112 from the portion where the straight connecting portion 1113 intersects with the nozzle cone portion 1112 to the discharge surface Ba is limited to only the surface portion being removed. Therefore, even if the mask layer removal process is performed, the ink will not flow out from, for example, the slit S which serves as a through hole.

[0237] In addition, Figures 8 to 11 The diagram illustrates the case where the slit S is formed from the discharge surface Ba side, but it is not limited to this. The slit S can also be formed from the adhesive surface Bb side.

[0238] However, when the slit S is formed by deep etching instead of through-processing, dry etching (DE2) is required until the portion where a straight through-hole 1113 is desired, and a sidewall mask layer 112 is formed until the portion where anisotropic wet etching (WE) is desired to stop. This is the same when the slit S is formed from either the discharge surface Ba or the bonding surface Bb of the monocrystalline silicon substrate B.

[0239] Furthermore, the method for forming the slit S through a through-process is not limited to a method that involves performing the through-process directly from the discharge surface Ba side or the bonding surface Bb side. For example, it can also be as follows: Figure 13 As shown, a slit S, serving as a through hole, is formed by deep drilling from both the discharge surface Ba side and the bonding surface Bb side, and then a sidewall mask layer 112 is formed in this slit S. Alternatively, at this time, it can also be done as follows: Figure 14 As shown, the part on the adhesive surface Bb side is pre-processed into a straight connecting portion 1113.

[0240] In addition, a protective film can also be formed on the nozzle plate 110 due to its long-term use for ink discharge.

[0241] In this case, after step A-7 or step B-6, a step is performed to form a protective film covering the surface including the nozzle flow path 111.

[0242] As a protective film, films made of materials that will not dissolve upon contact with ink can be selected and used, such as metal oxide films (tantalum pentoxide, hafnium oxide, niobium oxide, titanium oxide, zirconium oxide, etc.), metal silicate films containing silicon in the metal oxide film (tantalum silicate, hafnium silicate, niobium silicate, titanium silicate, zirconium silicate, etc.), and materials used in the formation of the mask layer. Alternatively, organic films such as polyimide, polyamide, and parylene can also be used as protective films.

[0243] The thickness of the protective film is not particularly limited; for example, it can be set to 0.05μm to 20μm.

[0244] Example

[0245] Next, the results of evaluating the preferred structure will be described with reference to embodiments and comparative examples of the present invention. The present invention will be specifically described below through embodiments, but the present invention is not limited thereto.

[0246] [Sample Creation]

[0247] A nozzle plate 110 is manufactured having 1000 nozzle flow paths 111 formed as in the following embodiments and comparative examples. Furthermore, each nozzle plate 110 is ground to a thickness of 175 μm. Moreover, with... Figure 15 A rectangular piezoelectric plate 130 with a cross-sectional shape of 50μm×250μm is joined to form an inkjet head 10, and the inkjet head 10 is mounted on the inkjet recording device 1.

[0248] (Example 1)

[0249] The nozzle flow path 111 is formed through the following steps A-1 to A-7.

[0250] Process A-1: ​​A surface mask layer 113 is formed on the discharge surface Ba of a single-crystal silicon substrate B with a crystal orientation of {100} and a thickness of 400μm by thermal oxidation.

[0251] A-2 process: Forming a slit pattern 115 on the surface mask layer 113.

[0252] A-3 process: The slit S is formed by dry etching (DE2) the monocrystalline silicon substrate B below the slit pattern 115.

[0253] Process A-4: Form a sidewall mask layer 112 in the slit S.

[0254] Furthermore, in processes A-2 to A-4, the cross-sectional shape of the surface of the straight connecting portion 1113 perpendicular to the vertical direction is... Figure 3A The 50μm × 250μm elongated mask layer 112 with two parallel sidewalls and a width of 2μm is formed. Additionally, the slit S is formed using a Bosch process based on a Si deep-cutting device.

[0255] Process A-5: Dry etching (DE1) is performed on the monocrystalline silicon substrate B below the surface mask layer 113 using a RIE device, thereby forming a 30μm × 30μm square opening pattern 114. In addition, CHF3 is used in the etching gas.

[0256] Process A-6: Dry etching (DE2) is performed on the monocrystalline silicon substrate B below the opening pattern 114 from the surface using a Si deep etching device, thereby forming a through hole.

[0257] A-7 process: Perform anisotropic wet etching (WE) based on KOH solution on the through hole to form a nozzle cone portion 1112 with four {111} crystal planes and a straight connecting portion 1113 formed by {101} crystal planes that are continuous with the end of the bonding surface Bb side of the nozzle cone portion 1112.

[0258] (Example 2)

[0259] In processes A-2 to A-4, such as Figure 5C As shown, a slit S and a sidewall mask layer 112 are formed in a rectangular shape with a cross-sectional shape of 50μm×250μm on the surface of the straight connecting part 1113 that is perpendicular to the vertical direction.

[0260] The other conditions are the same as in Example 1.

[0261] (Example 3)

[0262] The following steps A-8 and A-9 are performed between steps A-5 and A-6 to form a nozzle flow path 111 having a nozzle straight section 1111. Other conditions are the same as in Example 2.

[0263] A-8 process: Dry etching (DE2) is performed on the single crystal silicon substrate B below the opening pattern 114 from the surface using a Si deep etching device to form a nozzle straight section 1111 with a depth of 20μm.

[0264] A-9 process: After thermal oxidation of the single-crystal silicon substrate B, the oxide film at the bottom of the nozzle straight section 1111 is removed only by the RIE device.

[0265] (Example 4)

[0266] In processes A-2 to A-4, after rotating the single-crystal silicon substrate B by 45° while keeping the discharge surface Ba and the bonding surface Bb fixed, the slit S and the sidewall mask layer 112 are formed. Figure 5A As shown, a straight connected portion 1113 is formed by {100} surfaces.

[0267] The other conditions are the same as in Example 2.

[0268] (Example 5)

[0269] In processes A-3 and A-4, the slit S and the sidewall mask layer 112 are formed to gradually narrow as they move from the discharge surface Ba toward the bonding surface Bb.

[0270] Specifically, during the formation of the slit S, dry etching (DE2) is performed to make the width of the discharge surface Ba side 3 μm and the width of the bonding surface Bb side 1 μm.

[0271] The other conditions are the same as in Example 2.

[0272] (Example 6)

[0273] In process A-7, a nozzle flow path 111 is formed such that the crystal plane of the straight connecting portion 1113 is neither the {100} plane nor the {101} plane of the single crystal silicon substrate B, and the nozzle cone portion 1112 is left and right asymmetrical.

[0274] The other conditions are the same as in Example 2.

[0275] (Example 7)

[0276] The nozzle flow path 111 is formed through steps B-1 to B-6 described below. Other conditions are the same as in Example 2.

[0277] Process B-1: A surface mask layer 113 is formed on the surface of a single-crystal silicon substrate B by thermal oxidation.

[0278] B-2 process: Dry etching (DE1) is performed on the monocrystalline silicon substrate B below the surface mask layer 113 using a RIE device, thereby simultaneously forming the opening pattern 114 and the slit pattern 115.

[0279] Step B-3: After covering the opening pattern 114 with a resist layer, the single-crystal silicon substrate B below the slit pattern 115 is dry-etched (DE2) from the surface using a Si deep-cutting device, thereby performing deep-cutting processing until a depth of 180 μm is reached to form the slit S. Then, the resist layer covering the opening pattern 114 is removed.

[0280] Process B-4: A sidewall mask layer 112 is formed by thermally oxidizing the slit S. At this time, an oxide film is also formed on the opening pattern 114, but it is removed by etching using a RIE device.

[0281] Process B-5: Through-holes are formed by dry etching (DE2) the monocrystalline silicon substrate B below the opening pattern 114 from the surface.

[0282] B-6 process: By performing anisotropic wet etching (WE) based on KOH solution on the through hole, a nozzle cone portion 1112 with four {111} crystal planes and a straight connecting portion 1113 formed by {101} crystal planes that are continuous with the end of the bonding surface Bb side of the nozzle cone portion 1112 are formed.

[0283] (Example 8-1)

[0284] The following steps B-7 and B-8 are performed between steps B-4 and B-5 to form a nozzle flow path 111 having a nozzle straight section 1111. Other conditions are the same as in Example 7.

[0285] Process B-7: Using a Si deep-cutting device, a 20μm deep-cutting process is performed on the monocrystalline silicon substrate B below the opening pattern 114 from the surface using dry etching (DE2), thereby forming the nozzle straight section 1111.

[0286] Process B-8: A nozzle mask layer 116 is formed in the nozzle straight section 1111 by thermal oxidation of the single crystal silicon substrate B, and the oxide film on the bottom surface of the nozzle straight section 1111 is removed by the RIE device.

[0287] (Example 8-2)

[0288] By performing step B7 between steps B-3 and B-4, and step B8 between steps B-4 and B-5, while simultaneously forming the sidewall mask layer 112 and the nozzle mask layer 116 in step B-4, a nozzle flow path 111 having a nozzle straight portion 1111 is formed. Other conditions are the same as in Example 7.

[0289] Process B-7: Using a Si deep-cutting device, a 20μm deep-cutting process is performed on the monocrystalline silicon substrate B below the opening pattern 114 from the surface using dry etching (DE2), thereby forming the nozzle straight section 1111.

[0290] B-8 process: Remove the oxide film on the bottom surface of the nozzle straight section 1111 only by using the RIE device.

[0291] (Example 9)

[0292] Following process A-7, without grinding, the thickness of the single-crystal silicon substrate B is reduced from 400 μm to 175 μm using KOH-based anisotropic wet etching (WE). Then, as... Figure 6 As shown, hydrofluoric acid is used to remove the sidewall mask layer 112 that is disposed adjacent to the inner surface of the straight connecting portion 1113.

[0293] The other conditions are the same as in Example 4.

[0294] (Example 10)

[0295] In processes A-2 to A-4, a sidewall mask layer 112 is formed such that the cross-sectional shape of the surface of the straight connecting portion 1113 perpendicular to the vertical direction is 50μm × 59μm. Furthermore, a nozzle flow path 111 with a maximum length of 20μm and a cone height h is formed.

[0296] The other conditions are the same as in Example 2.

[0297] (Comparative Example 1)

[0298] Anisotropic wet etching (WE) was performed on a single-crystal silicon substrate B with a {100} crystal orientation and a thickness of 400 μm to form a nozzle flow path 111 with a square cross-sectional shape of 250 μm × 250 μm on a surface perpendicular to the vertical direction. In Comparative Example 1, the thickness of the nozzle plate 110 was ground from 400 μm to 250 μm.

[0299] exist Figure 16A The image shows an enlarged top view of the nozzle plate 110 equipped with the nozzle flow path 111 of this modified example. Additionally, in... Figure 16B The text indicates that the nozzle plate 110 in this modified example is... Figure 15 A cross-sectional view of the surface of the inkjet head 10 perpendicular to the front-back direction after the piezoelectric plate 130 is joined.

[0300] (Comparative Example 2)

[0301] Anisotropic wet etching (WE) is performed on a single-crystal silicon substrate B with a crystal orientation of {100} and a thickness of 400 μm to form a nozzle flow path 111 with a cross-sectional shape of 50 μm × 50 μm perpendicular to the vertical direction.

[0302] exist Figure 17A The image shows an enlarged top view of the nozzle plate 110 equipped with the nozzle flow path 111 of this modified example. Additionally, in... Figure 17B In the middle, it indicates that the nozzle plate 110 in this modified example is connected to... Figure 15 A cross-sectional view of the inkjet head 10 after the piezoelectric plate 130 is joined, perpendicular to the front-to-back direction. Additionally, in Figure 17C The middle section represents a cross-sectional view of a plane perpendicular to the left and right directions.

[0303] (Comparative Example 3)

[0304] Anisotropic wet etching (WE) is performed on a single-crystal silicon substrate B with a crystal orientation of {100} and a thickness of 400 μm to form a nozzle flow path 111 with a cross-sectional shape of a diamond shape having a diagonal of 50 μm × 50 μm and a surface perpendicular to the vertical direction.

[0305] exist Figure 18A The image shows an enlarged top view of the nozzle plate 110 equipped with the nozzle flow path 111 of this modified example. Additionally, in... Figure 18B The text indicates that the nozzle plate 110 in this modified example is... Figure 15 A cross-sectional view of the inkjet head 10 after the piezoelectric plate 130 is joined, perpendicular to the front-to-back direction. Additionally, in Figure 18C The middle section represents a cross-sectional view of a plane perpendicular to the left and right directions.

[0306] The following tests 1-2 were conducted using an inkjet recording device 1 equipped with an inkjet head 10 having a nozzle plate 110 of the above embodiments 1-9 and comparative examples 1-3.

[0307] [Experiment 1. Launch Angle Test]

[0308] When ejecting UV ink heated to a viscosity of 8 cP at a driving voltage that produces an average droplet velocity of approximately 6 m / s, the ejection angle was evaluated within ± a few degrees for 1000 nozzle openings N. Here, the ejection angle refers to the angle of the ejected UV ink relative to the nozzle's central axis.

[0309] [Experiment 2. Maximum Speed ​​Test]

[0310] At a driving frequency of 40 kHz, the injection velocity of UV ink heated to a viscosity of 8 cP was increased from 5 m / s to measure the injection velocity at which injection defects occurred in 5 or more of 100 nozzle openings N. Furthermore, cases with an injection velocity of 11 m / s or higher were rated as "◎", cases with an injection velocity of 9 m / s or higher were rated as "〇", cases with an injection velocity of 8 m / s or higher were rated as "△", and cases with an injection velocity of 7 m / s or lower were rated as "×".

[0311] The results of experiments 1-2 are shown in Table I.

[0312] [Table 1]

[0313]

[0314] In Comparative Example 1, the more unstable the curvature of the fluid surface, the more likely it is to fail to eject normally, and the more likely it is to produce ejection defects.

[0315] In Comparative Example 2, the resistance during ink ejection increased, making it easier to generate bubbles. In addition, ink could not be ejected unless the driving voltage was increased to 30V.

[0316] In Comparative Example 3, the maximum length of the cone height h decreased, resulting in deteriorated meniscus stability. Furthermore, the resistance during ink ejection increased, making it easier to generate bubbles; additionally, ink could not be ejected unless the driving voltage was increased to 30V.

[0317] [evaluate]

[0318] Comparing Examples 1-10 and Comparative Examples 1-3, it can be seen that when the nozzle flow path 111 is manufactured, a sidewall mask layer 112 is formed so that the cross-sectional shape of the surface of the straight connecting portion 1113 perpendicular to the vertical direction is consistent with the cross-sectional shape of the surface of the ink flow path of the piezoelectric plate 130 perpendicular to the vertical direction. As a result, the shape of the meniscus becomes stable, and the best injection characteristics are obtained.

[0319] In particular, when comparing Examples 3, 8-1, and 8-2 with other examples, it is found that by forming a nozzle straight section 1111 in the nozzle flow path 111, the resistance during ink ejection increases, and the driving voltage rises slightly. However, the maximum length of the cone height h also increases, and the meniscus shape becomes more stable.

[0320] Furthermore, in both Embodiment 1 and Embodiment 2, the cross-sectional shape of the surface of the straight connecting portion 1113 perpendicular to the vertical direction is consistent with the cross-sectional shape of the surface of the ink flow path of the piezoelectric plate 130 perpendicular to the vertical direction. Therefore, optimal injection angle and meniscus stability can be achieved. In particular, in the case of Embodiment 2, all the ink enters the nozzle flow path 111 from the piezoelectric plate 130, resulting in less resistance and thus a slightly lower driving voltage.

[0321] Furthermore, comparing Embodiment 2 with Embodiment 4 and Embodiment 6, it can be seen that by forming a straight connecting portion 1113 whose crystal plane is composed of the {100} or {101} plane of the single-crystal silicon substrate B, the ejection angle is more stable. This is because the nozzle cone portion 1112 becomes symmetrical from left to right, thus ensuring symmetrical ink flow.

[0322] Furthermore, comparing Embodiment 5 with other embodiments, it can be seen that by forming the slit S and the sidewall mask layer 112 to gradually widen from the first surface toward the second surface opposite to the first surface, the ejection angle becomes more stable. This is because the sidewall mask layer 112 can be easily embedded without gaps, thereby improving the accuracy of the straight connecting portion 1113.

[0323] Furthermore, comparing Embodiment 2 with Embodiment 7, or Embodiment 3 with Embodiments 8-1 and 8-2, it can be seen that by simultaneously forming the opening pattern 114 and the slit pattern 115, the ejection angle is more stable. This is because it is easier to align the nozzle opening N with the slit S, thus forming a nozzle flow path 111 with higher symmetry.

[0324] Furthermore, comparing Embodiment 4 and Embodiment 9, it can be seen that even if the thickness is reduced by removing the single-crystal silicon substrate B through anisotropic wet etching (WE), or the sidewall mask layer 112 disposed adjacent to the straight connecting portion 1113 is removed, the injection characteristics will not be affected.

[0325] Furthermore, comparing Example 8-1 with Example 8-2, it can be seen that the sidewall mask layer 112 and the nozzle mask layer 116 can be formed simultaneously or separately, without affecting the injection characteristics.

[0326] Furthermore, comparing Example 10 with Comparative Examples 2 and 3, it can be seen that if the nozzle flow path 111 is such that the driving voltage is 29V or less to make the droplet velocity average about 6m / s, it has the stability of the meniscus that can withstand use as an inkjet recording device 1.

[0327] If, as in Example 10, the maximum length of the cone height h is 20 μm or more, the cross-sectional area of ​​the surface of the straight connecting portion 1113 perpendicular to the vertical direction is larger than that of Comparative Examples 2 and 3, and the resistance during ink ejection is reduced.

[0328] Industrial availability

[0329] The present invention can be used to manufacture a nozzle plate, a droplet discharge head, a droplet discharge device, and a method for manufacturing a nozzle plate that can achieve both high density of nozzle opening and optimal injection characteristics.

[0330] Explanation of reference numerals in the attached figures: 1…droplet ejection device (inkjet recording device); 10…droplet ejection head (inkjet head); 110…nozzle plate; 111…nozzle flow path; 1111…straight section of nozzle; 1112…conical section of nozzle; 1113…straight connecting section; 112…sidewall mask layer; 113…surface mask layer; 114…opening pattern; 115…slit pattern; 116…nozzle mask layer; B…monocrystalline silicon substrate; Ba…ejection surface (first surface); Bb…adhesion surface (second surface); h…cone height; N…nozzle opening; S…slit; DE1, DE2…dry etching; WE…anisotropic wet etching.

Claims

1. A nozzle plate comprising a plurality of nozzle flow paths having nozzle openings for discharging droplets formed on a first surface of a monocrystalline silicon substrate, wherein, The nozzle flow path includes: The nozzle cone portion, as it moves from the first surface toward the second surface opposite the first surface, gradually widens its cross-sectional area, i.e., its flow path area, which is orthogonal to the droplet discharge direction; and The straight connecting portion is continuous with the end of the second face side of the nozzle cone portion, and the opposing set of faces of the straight connecting portion are parallel. In the intersection of the face constituting the straight connecting portion and the second face, the length of the side of the opposite set of faces is longer than the length of the side of the other faces. The nozzle cone includes four faces with {111} crystal planes. The crystal planes of the faces whose side length is longer than the side length of the other faces among the edges of the face that constitutes the straight connecting portion and intersects with the second face are composed of {100} planes.

2. A nozzle plate comprising a plurality of nozzle flow paths having nozzle openings for discharging droplets formed on a first surface of a single-crystal silicon substrate, wherein, The nozzle flow path includes: The nozzle cone portion, as it moves from the first surface toward the second surface opposite the first surface, gradually widens its cross-sectional area, i.e., its flow path area, which is orthogonal to the droplet discharge direction; and The straight connecting portion is continuous with the end of the second face side of the nozzle cone portion, and the opposing set of faces of the straight connecting portion are parallel. In the intersection of the face constituting the straight connecting portion and the second face, the length of the side of the opposite set of faces is longer than the length of the side of the other faces. The nozzle cone-shaped portion is composed of four faces with {111} crystal planes. The crystal planes of the faces whose side length is longer than the side length of the other faces among the edges of the face that constitutes the straight connecting portion and intersects with the second face are composed of {100} planes.

3. The nozzle plate according to claim 1 or 2, wherein, At least a portion of the space between the intersection of the nozzle cone portion and the straight connecting portion and the first surface has a sidewall mask layer.

4. The nozzle plate according to claim 3, wherein, The sidewall mask layer has a shape that gradually narrows as it moves from the first surface toward the second surface or as it moves from the second surface toward the first surface.

5. The nozzle plate according to claim 1 or 2, wherein, The nozzle flow path includes a nozzle straight section that is continuous with the end of the first face side of the nozzle cone.

6. The nozzle plate according to claim 5, wherein, The maximum portion of the flow path area of ​​the straight section of the nozzle is less than or equal to the flow path area of ​​the end of the first face side of the conical section of the nozzle.

7. The nozzle plate according to claim 1 or 2, wherein, The maximum length of the cone height from the first surface to the end of the second surface side of the nozzle cone is 20 μm or more.

8. A nozzle plate comprising a plurality of nozzle flow paths having nozzle openings for discharging droplets formed on a first surface of a single-crystal silicon substrate, wherein, The nozzle flow path includes: The nozzle cone portion, as it moves from the first surface toward the second surface opposite the first surface, gradually widens its cross-sectional area, i.e., its flow path area, which is orthogonal to the droplet discharge direction; and The straight connecting portion is continuous with the end of the second face side of the nozzle cone portion, and the opposing set of faces of the straight connecting portion are parallel. In the intersection of the face constituting the straight connecting portion and the second face, the length of the side of the opposite set of faces is longer than the length of the side of the other faces. The nozzle cone includes four faces with {111} crystal planes. At least a portion of the space between the intersection of the nozzle cone portion and the straight connecting portion and the first surface has a sidewall mask layer.

9. A nozzle plate comprising a plurality of nozzle flow paths having nozzle openings for discharging droplets formed on a first surface of a single-crystal silicon substrate, wherein, The nozzle flow path includes: The nozzle cone portion, as it moves from the first surface toward the second surface opposite the first surface, gradually widens its cross-sectional area, i.e., its flow path area, which is orthogonal to the droplet discharge direction; and The straight connecting portion is continuous with the end of the second face side of the nozzle cone portion, and the opposing set of faces of the straight connecting portion are parallel. In the intersection of the face constituting the straight connecting portion and the second face, the length of the side of the opposite set of faces is longer than the length of the side of the other faces. The nozzle cone-shaped portion is composed of four faces with {111} crystal planes. At least a portion of the space between the intersection of the nozzle cone portion and the straight connecting portion and the first surface has a sidewall mask layer.

10. The nozzle plate according to claim 8 or 9, wherein, The crystal planes of the faces whose side length is longer than the side length of the other faces among the edges of the face that constitutes the straight connecting portion and intersects with the second face are composed of {101} faces.

11. The nozzle plate according to claim 8 or 9, wherein, The sidewall mask layer has a shape that gradually narrows as it moves from the first surface toward the second surface or as it moves from the second surface toward the first surface.

12. The nozzle plate according to claim 8 or 9, wherein, The nozzle flow path includes a nozzle straight section that is continuous with the end of the first face side of the nozzle cone.

13. The nozzle plate according to claim 12, wherein, The maximum portion of the flow path area of ​​the straight section of the nozzle is less than or equal to the flow path area of ​​the end of the first face side of the conical section of the nozzle.

14. The nozzle plate according to claim 8 or 9, wherein, The maximum length of the cone height from the first surface to the end of the second surface side of the nozzle cone is 20 μm or more.

15. A nozzle plate comprising a plurality of nozzle flow paths having nozzle openings for discharging droplets formed on a first surface of a single-crystal silicon substrate, wherein, The nozzle flow path includes: The nozzle cone portion, as it moves from the first surface toward the second surface opposite the first surface, gradually widens its cross-sectional area, i.e., its flow path area, which is orthogonal to the droplet discharge direction; and The straight connecting portion is continuous with the end of the nozzle conical portion on the second surface and is disposed on the second surface. At least a portion of the space between the intersection of the nozzle cone portion and the straight connecting portion and the first surface has a sidewall mask layer. The nozzle cone includes four faces with {111} crystal planes.

16. A nozzle plate comprising a plurality of nozzle flow paths having nozzle openings for discharging droplets formed on a first surface of a single-crystal silicon substrate, wherein, The nozzle flow path includes: The nozzle cone portion, as it moves from the first surface toward the second surface opposite the first surface, gradually widens its cross-sectional area, i.e., its flow path area, which is orthogonal to the droplet discharge direction; and The straight connecting portion is continuous with the end of the nozzle conical portion on the second surface and is disposed on the second surface. At least a portion of the space between the intersection of the nozzle cone portion and the straight connecting portion and the first surface has a sidewall mask layer. The nozzle cone is composed of four faces with a {111} crystal plane.

17. The nozzle plate according to claim 15 or 16, wherein, The sidewall mask layer has a shape that gradually narrows as it moves from the first surface toward the second surface or as it moves from the second surface toward the first surface.

18. The nozzle plate according to claim 15 or 16, wherein, The nozzle flow path includes a nozzle straight section that is continuous with the end of the first face side of the nozzle cone.

19. The nozzle plate according to claim 18, wherein, The maximum portion of the flow path area of ​​the straight section of the nozzle is less than or equal to the flow path area of ​​the end of the first face side of the conical section of the nozzle.

20. The nozzle plate according to claim 15 or 16, wherein, The maximum length of the cone height from the first surface to the end of the second surface side of the nozzle cone is 20 μm or more.

21. A droplet discharge head, mounted on a droplet discharge device, wherein, The nozzle plate is provided with any one of claims 1 to 20.

22. A droplet discharge device, wherein, It has the droplet discharge head as described in claim 21.

23. A method for manufacturing a nozzle plate, specifically a method for manufacturing a nozzle plate for a droplet discharge head, wherein, include: The first step involves forming a surface mask layer on the first surface of a single-crystal silicon substrate with a crystal orientation of {100}. The second step involves forming a slit pattern in the surface mask layer; The third step involves forming the slit by dry etching the monocrystalline silicon substrate located below the slit pattern, either by performing a through-processing process from the surface or by performing a deep-cutting process from the surface to the middle using dry etching. The fourth step is to form a sidewall mask layer in the slit; The fifth step involves forming a circular or polygonal opening pattern on the surface mask layer to form the nozzle opening. The sixth step involves forming a through hole by dry etching the single-crystal silicon substrate located below the opening pattern from the surface. as well as In the seventh step, the through hole is enlarged by anisotropic wet etching of the single-crystal silicon substrate to form a nozzle cone portion and a straight connecting portion continuous with the end of the nozzle cone portion facing the second surface opposite to the first surface.

24. The method for manufacturing a nozzle plate according to claim 23, wherein, The process takes place between the fifth and sixth steps: The eighth step involves forming a nozzle straight section by dry etching the single-crystal silicon substrate located below the opening pattern from the surface to the middle. as well as The ninth step involves forming a nozzle mask layer along the inner surface of the straight portion of the nozzle.

25. A method for manufacturing a nozzle plate, specifically a method for manufacturing a nozzle plate for a droplet discharge head, wherein... include: The first step involves forming a surface mask layer on the first surface of a single-crystal silicon substrate with a crystal orientation of {100}. In the second step, a circular or polygonal opening pattern that becomes the nozzle opening and a slit pattern that becomes a slit are simultaneously formed on the surface mask layer. The third step involves forming a slit by dry etching the monocrystalline silicon substrate located below the slit pattern, either through the surface or deep through the surface to the middle. The fourth step is to form a sidewall mask layer in the slit; The fifth step involves forming through holes by dry etching the single-crystal silicon substrate located below the opening pattern from the surface. as well as In the sixth step, the through hole is enlarged by anisotropic wet etching of the single-crystal silicon substrate to form a nozzle cone portion and a straight connecting portion that is continuous with the end of the nozzle cone portion facing the second surface opposite to the first surface.

26. The method for manufacturing a nozzle plate according to claim 25, wherein, This process takes place between the third and fifth steps: The seventh step involves forming a nozzle straight section by dry etching the single-crystal silicon substrate located below the opening pattern from the surface to the middle. as well as The eighth step is to form a nozzle mask layer along the inner surface of the straight portion of the nozzle.

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