Multi-nozzle head, multi-nozzle head production method, and droplet ejection device

Abstract

This multi-nozzle head production method comprises forming nozzle holes by preparing a substrate that has a plurality of recesses on the upper surface thereof, forming a metal seed layer on the upper surface and the plurality of recesses of the substrate, forming insulators on the metal seed layer at the bottoms of the plurality of recesses via an electrostatic inkjet method, forming a first metal layer on an exposed portion of the metal seed layer, forming a resist pattern on the first metal layer and the insulators, forming a second metal layer on an exposed portion of the first metal layer, and removing the resist pattern, the insulators, and the metal seed layer that overlaps with the insulators, thereby processing the base material.

Description

Multi-nozzle head, manufacturing method thereof, and droplet ejection device

[0001] The present invention relates to a multi-nozzle head, a method for manufacturing a multi-nozzle head, and a droplet ejection device.

[0002] In recent years, inkjet printing technology has been applied to industrial processes. One example is the manufacturing process of color filters for liquid crystal displays. Conventionally, so-called piezo-type heads, which eject droplets using mechanical pressure or vibration, have been widely used in inkjet printing technology. However, electrostatic ejection inkjet heads, which can eject finer droplets, are attracting attention. Patent Document 1 discloses an electrostatic ejection inkjet recording device.

[0003] Japanese Patent Application Publication No. 10-34967

[0004] Recently, the development of multi-nozzle heads for electrostatic ejection inkjet heads has been progressing from the viewpoint of improving productivity. However, in multi-nozzle heads, there is a risk of nozzle openings being formed imperfectly, and it is difficult to form the nozzle openings uniformly. Therefore, a method for forming the nozzle openings stably is required.

[0005] Therefore, an object of the present invention is to provide a method for manufacturing a multi-nozzle head that can stably form nozzle openings and eject droplets uniformly.

[0006] According to one embodiment of the present invention, there is provided a method for manufacturing a multi-nozzle head, the method including: preparing a substrate having an upper surface and a lower surface opposite to the upper surface, the substrate having a plurality of recesses on the upper surface; forming a metal seed layer on the upper surface of the substrate and on the plurality of recesses; forming a first insulator on bottoms of the plurality of recesses in the metal seed layer using an electrostatic ejection inkjet method; forming a first metal layer on exposed portions of the metal layer seed; forming a second insulator on the metal layer and the first insulator; forming a second metal layer on exposed portions of the first metal layer; removing the second insulator, the first insulator, and the metal seed layer overlapping the first insulator to form a nozzle opening; and processing the substrate.

[0007] In the method for manufacturing a multi-nozzle head described above, the first insulator may have a size of 1 μm or more and 100 μm or less.

[0008] In the method for manufacturing a multi-nozzle head described above, a mask formed by an electrostatic ejection type ink jet method may be used when forming the second insulator.

[0009] In the method for manufacturing a multi-nozzle head described above, the diameter of the nozzle opening may be adjusted in accordance with the ejection amount of the first insulator.

[0010] In the above-described method for manufacturing a multi-nozzle head, the metal seed layer overlapping the first insulator may be removed by etching.

[0011] In the above-described method for manufacturing a multi-nozzle head, the metal seed layer overlapping the first insulator may be removed by wet etching.

[0012] In the above-described method for manufacturing a multi-nozzle head, the metal seed layer overlapping the first insulator may be removed by using a lift-off method.

[0013] In the method for manufacturing a multi-nozzle head described above, the metal seed layer may have a thickness of 10 nm or more and 100 nm or less.

[0014] In the above-described method for manufacturing a multi-nozzle head, the first metal layer may have a thickness of 1 μm or more and 10 μm or less, and the second metal layer may have a thickness of 10 μm or more and 100 μm or less.

[0015] In the method for manufacturing the multi-nozzle head, the base material may be processed to form a spacer that maintains a distance from the discharge target.

[0016] In the method for manufacturing the multi-nozzle head described above, an electrode may be formed in contact with a part of the spacer and having an opening in a portion corresponding to the nozzle opening.

[0017] According to one embodiment of the present invention, there is provided a multi-nozzle head including: a plate portion having through holes; a droplet discharge nozzle portion including a plurality of droplet discharge nozzles disposed corresponding to the through holes of the plate portion and configured to discharge droplets by an electrostatic discharge method; a pseudo-nozzle portion disposed around the droplet discharge nozzle portion of the plate portion and including a plurality of pseudo-nozzles with closed tips; and a spacer disposed on the plate portion on the tip side of the droplet discharge nozzles and configured to maintain a distance from an object onto which the droplets are discharged.

[0018] In the above multi-nozzle head, the spacer may have a pillar portion in contact with the plate portion, and a flat portion provided opposite the plate portion and in contact with the pillar portion.

[0019] The multi-nozzle head may further include an electrode provided on the spacer so as to face the droplet ejection nozzles.

[0020] According to one embodiment of the present invention, there is provided a droplet ejection device including the above multi-nozzle head.

[0021] By using one embodiment of the present invention, it is possible to provide a method for manufacturing a multi-nozzle head that is capable of stably forming nozzle openings, and by using one embodiment of the present invention, it is possible to eject droplets uniformly.

[0022] 1 is a schematic diagram of a droplet ejection device according to an embodiment of the present invention; FIG. 2 is a plan view of a multi-nozzle head according to an embodiment of the present invention; FIG. 3 is a cross-sectional view of a multi-nozzle head according to an embodiment of the present invention; FIG. 4 is an enlarged view of a plan view of a multi-nozzle head according to an embodiment of the present invention; FIG. 5 is a perspective view of a droplet ejection nozzle according to an embodiment of the present invention; FIG. 6 is a top view of a droplet ejection nozzle according to an embodiment of the present invention; FIG. 7 is a cross-sectional view of a droplet ejection nozzle according to an embodiment of the present invention; FIG. 8 is a top view of a pseudo nozzle according to an embodiment of the present invention; FIG. 9 is a cross-sectional view of a pseudo nozzle according to an embodiment of the present invention; FIG. 10 is a manufacturing flow diagram of a multi-nozzle head according to an embodiment of the present invention; FIG. 11 is a manufacturing flow diagram of a multi-nozzle head according to an embodiment of the present invention; FIG. 12 is a manufacturing flow diagram of a multi-nozzle head according to an embodiment of the present invention; FIG. 13 is a manufacturing flow diagram of a multi-nozzle head according to an embodiment of the present invention; FIG. 14 is a manufacturing flow diagram of a multi-nozzle head according to an embodiment of the present invention; FIG. 15 is a cross-sectional view of a multi-nozzle head according to an embodiment of the present invention; FIG. 16 is a cross-sectional view of a multi-nozzle head according to an embodiment of the present invention;

[0023] Hereinafter, each embodiment of the invention disclosed in this application will be described with reference to the drawings. However, the present invention can be embodied in various forms without departing from the spirit of the invention, and should not be construed as being limited to the description of the embodiments exemplified below.

[0024] In the drawings referred to in this embodiment, identical parts or parts having similar functions are designated by the same or similar reference numerals (reference numerals simply suffixed with A, B, -1, -2, etc.), and repeated explanations thereof may be omitted. Also, for convenience of explanation, the dimensional ratios of the drawings may differ from the actual ratios, and some components may be omitted from the drawings.

[0025] Furthermore, in the detailed description of the present invention, when defining the positional relationship between a certain component and another component, "above" and "below" do not only mean being located directly above or directly below a certain component, but also include cases where there are other components interposed between them, unless otherwise specified.

[0026] First Embodiment (1-1. Configuration of Droplet Discharge Device 100) FIG. 1 is a schematic diagram of a droplet discharge device 100 according to one embodiment of the present invention.

[0027] The droplet ejection device 100 includes a control unit 110 , a storage unit 115 , a power supply unit 120 , a drive unit 130 , a droplet ejection unit 140 , and a target object holder 160 .

[0028] The control unit 110 includes a central processing unit (CPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other arithmetic processing circuit. The control unit 110 controls the ejection process of the droplet ejection unit 140 using a preset droplet ejection program.

[0029] The storage unit 115 functions as a database that stores a droplet ejection program and various information used in the droplet ejection program. The storage unit 115 uses a memory, an SSD (Solid State Drive), or a memory-capable element.

[0030] The power supply unit 120 is connected to the control unit 110, the drive unit 130, and the droplet ejection unit 140. The power supply unit 120 applies a voltage to the droplet ejection unit 140 based on a signal input from the control unit 110. In this example, the power supply unit 120 applies a pulsed voltage (1000 V in this example) to the droplet ejection unit 140. Note that the voltage is not limited to a pulsed voltage, and a constant voltage may be applied constantly. The voltage applied from the power supply unit 120 to the multi-nozzle head 150 causes the liquid held in the ink tank 145 to be ejected as droplets from the tip 153 a (see FIG. 2B ) of the droplet ejection nozzle 153 (described later) of the multi-nozzle head 150 in the direction of the target object 200 (third direction D3).

[0031] The drive unit 130 is composed of drive members such as a motor, a belt, and gears. Based on instructions from the control unit 110, the drive unit 130 moves the droplet discharge unit 140 (more specifically, the multi-nozzle head 150 described later) in one direction (in this example, the second direction D2) relative to the target object holder 160. Note that the drive unit 130 may move the target object while fixing the droplet discharge unit 140. The drive unit 130 may also be used in combination with a goniostage to fine-tune the position of the multi-nozzle head 150.

[0032] The droplet ejection unit 140 includes an ink tank 145 and a multi-nozzle head 150. The multi-nozzle head 150 uses electrostatic ejection type inkjet nozzles. Details of the multi-nozzle head 150 will be described later. The multi-nozzle head 150 is used by being fixed to a mount and attachment (not shown). The mount and attachment may have grooves (long holes) in the portions corresponding to the droplet ejection nozzles 153 for temporarily storing ink supplied from the ink tank 145.

[0033] The object holder 160 has a function of holding the object 200. In this example, a stage is used as the object holder 160. There are no particular restrictions on the mechanism by which the object holder 160 holds the object 200, and a general holding mechanism is used. In this example, the object 200 is vacuum-sucked to the object holder 160. However, this is not limiting, and the object holder 160 may hold the object 200 using a fixture.

[0034] (1-2. Configuration of multi-nozzle head 150) The configuration of the multi-nozzle head 150 will be described in detail below. Fig. 2A is a plan view of the multi-nozzle head 150. Fig. 2B is a cross-sectional view of the multi-nozzle head 150 between C1 and C2. Fig. 3 is an enlarged view of the plan view of the multi-nozzle head 150. Fig. 4 is a perspective view of the droplet discharge nozzle 153. Fig. 5A is a top view of the droplet discharge nozzle 153. Fig. 5B is a cross-sectional view of the droplet discharge nozzle 153 between A1 and A2. Fig. 6A is a top view of the pseudo-nozzle 155. Fig. 6B is a cross-sectional view of the pseudo-nozzle 155 between B1 and B2.

[0035] As shown in FIGS. 2A and 2B, the multi-nozzle head 150 includes a plate portion 151, a droplet ejection nozzle portion 152, and a pseudo-nozzle portion 154.

[0036] The plate portion 151 is provided in a plate shape. The plate portion 151 extends in the first direction D1. The plate portion 151 is made of a metal material such as nickel. The thickness of the plate portion 151 is set appropriately. In this example, the thickness of the plate portion is not less than 10 μm and not more than 100 μm.

[0037] As shown in FIGS. 4, 5A, and 5B, the droplet discharge nozzle section 152 is provided on one surface side (the lower surface side in this example) of the plate section 151. The droplet discharge nozzle section 152 includes a plurality of droplet discharge nozzles 153. The droplet discharge nozzles 153 are arranged side by side in the first direction D1. In this embodiment, droplet discharge nozzles 153-1, 153-2, ..., 153-(N-1), and 153-N are provided on the plate section 151. N is a natural number equal to or greater than 20. In this example, N=21. Note that when there is no need to separately describe the droplet discharge nozzles 153-1, 153-2, ..., 153-(N-1), and 153-N, they will be described as droplet discharge nozzles 153. A metal material such as nickel is used for the droplet discharge nozzles 153. The droplet discharge nozzles 153 have a tapered shape.

[0038] The plate portion 151 has a through-hole 151o in a portion corresponding to (overlapping with) the droplet discharge nozzle 153, the through-hole 151o having an inner diameter r151o larger than the inner diameter r153a of the discharge port (opening 153ao of the tip portion 153a of the droplet discharge nozzle 153). The inner diameter r151o of the through-hole 151o of the plate portion 151 may be 1 μm or more and 1 mm or less, preferably 10 μm or more and 100 μm or less. The inner diameter r153a of the tip portion 153a of the droplet discharge nozzle 153 may be several hundred nanometers or more and 500 μm or less, preferably 1 μm or more and 100 μm or less, more preferably 3 μm or more and 50 μm or less, and even more preferably 5 μm or more and 20 μm or less. In this embodiment, a voltage may be applied to the droplet ejection nozzles 153, to the plate portion 151 (or the ink tank 145), or to the liquid (ink). When a voltage is applied to the plate portion 151 or the droplet ejection nozzles 153, an electrode may be provided. The electrode may be made of tungsten, nickel, molybdenum, titanium, gold, silver, copper, platinum, or the like. In this case, multiple electrodes may be provided so that the voltage is applied uniformly to the entire plate portion 151. Furthermore, although this embodiment shows an example in which a voltage is applied to the droplet ejection nozzles 153, the plate portion 151, or the ink, a voltage may also be applied to a jig (for example, a mount or attachment) that holds the multi-nozzle head 150.

[0039] As shown in FIG. 2B , the pseudo-nozzle portion 154 is provided on the same surface of the plate portion 151 as the droplet ejection nozzle portion 152. The pseudo-nozzle portion 154 includes a plurality of pseudo-nozzles 155. The pseudo-nozzle portion 154 is provided on the periphery (outside) of the droplet ejection nozzle portion 152. In this example, the pseudo-nozzle portions 154 are provided on both sides of the droplet ejection nozzle portion 152 in the first direction D1. The plurality of pseudo-nozzles 155 may also be arranged in a predetermined region from the outermost pseudo-nozzle 155 (in this example, pseudo-nozzle 155L-1). From the viewpoint of electric field strength in the periphery, the plurality of pseudo-nozzles 155 may be arranged over an entire range of 1 mm to 5 mm (preferably 2 mm) from the outermost pseudo-nozzle 155 in the first direction D1. In this case, the number of pseudo-nozzles 155 provided on one side of the droplet ejection nozzle portion 152 in the first direction D1 may be ⅕ or more of the number of droplet ejection nozzles 153. For example, the number of pseudo-nozzles 155 provided on one side of the droplet discharge nozzle portion 152 in the first direction D1 may be 5 to 50, preferably 10 to 30. In the case of this embodiment, a left pseudo-nozzle 155L including five pseudo-nozzles 155 (pseudo-nozzles 155-L1 to 155-L5) is provided on the left side of the droplet discharge nozzle portion 152 including 21 droplet discharge nozzles 153. Similarly, a right pseudo-nozzle 155R including five pseudo-nozzles 155 (pseudo-nozzles 155-R1 to 155-R5) is provided on the right side of the droplet discharge nozzle portion 152. Note that when it is not necessary to separately describe the pseudo-nozzles as 155-L1 to 155-L5, they will be described as pseudo-nozzles 155.

[0040] 3, the distance dis1 between adjacent droplet discharge nozzles (the distance between droplet discharge nozzle 153-1 and droplet discharge nozzle 153-2), the distance dis2 between adjacent droplet discharge nozzles 153 and pseudo-nozzles 155 (the distance between droplet discharge nozzle 153-1 and pseudo-nozzle 155-L5), and the distance dis3 between adjacent pseudo-nozzles 155 (the distance between pseudo-nozzle 155-L4 and pseudo-nozzle 155-L5) are all the same. In this example, the distances dis1, dis2, and dis3 between the nozzles are 200 μm.

[0041] As shown in FIGS. 6A and 6B , the tip 155 a of the pseudo-nozzle 155 does not have an opening and is closed. Therefore, the pseudo-nozzle 155 does not eject droplets. In this example, the pseudo-nozzle 155 is filled to the same height as the upper part of the plate portion 151. The pseudo-nozzle 155 is made of the same material as the droplet ejection nozzle 153. The pseudo-nozzle 155 may have the same shape as the droplet ejection nozzle 153. In this case, the height H155 of the pseudo-nozzle 155 (also referred to as the first height; specifically, the height from the lower surface 151 a of the plate portion 151 to the tip 155 a of the pseudo-nozzle 155) may be the same as the height H153 of the droplet ejection nozzle 153 (also referred to as the second height; specifically, the height (vertical distance) from the lower surface 151 a of the plate portion 151 to the tip 153 a of the droplet ejection nozzle 153 (the horizontal plane of the tip 153 a)).

[0042] Here, when droplets are discharged by an electrostatic discharge method using a multi-nozzle head including multiple nozzles, the electric field may be stronger in the peripheral region of the plate than in the center of the plate. In the case of the multi-nozzle head 150 of this embodiment, the pseudo-nozzle portion 154 is arranged around the droplet discharge nozzle portion 152. In other words, multiple pseudo-nozzles 155 are arranged in the region where the electric field is stronger. Since the tips of the multiple pseudo-nozzles 155 are closed, droplets are not discharged. On the other hand, the electric field in the region where the droplet discharge nozzles 153 are arranged is uniform. This makes it possible to uniform the size of droplets discharged from each droplet discharge nozzle 153.

[0043] (1-3. Manufacturing Method of Multi-Nozzle Head 150) A manufacturing method of the multi-nozzle head 150 will be described with reference to the drawings. Figures 7A to 11B are cross-sectional views showing the manufacturing flow of the multi-nozzle head.

[0044] First, as shown in Fig. 7B, a substrate 2000 is prepared, which has a plurality of recesses for forming the droplet ejection nozzles 153 and the pseudo-nozzles 155. In this embodiment, the substrate 2000 has a first surface (upper surface) 2000A and a second surface (lower surface) 2000B opposite the first surface 2000A. The substrate 2000 includes a first substrate 2001 and a second substrate 2005. In addition, the first surface 2000A is provided with a plurality of first recesses 2007 for forming the droplet ejection nozzles and a plurality of second recesses 2009 provided around the first recesses 2007 for forming the pseudo-nozzles.

[0045] The substrate 2000 is formed by a film formation process, a photolithography process, and an etching process. Specifically, as shown in Fig. 7A, a plate-shaped first substrate 2001 is prepared. The first substrate 2001 may be a metal substrate, a semiconductor material, or an insulating substrate or a semiconductor substrate with a conductive film formed on the upper surface thereof.

[0046] 7B , second substrate 2005 is formed on first substrate 2001. Second substrate 2005 may be formed by forming an insulating layer and then processing it using photolithography, etching, or the like. At this time, first substrate 2001 is exposed at the bottoms of first recess 2007 and second recess 2009.

[0047] Although the above describes an example in which the second base material 2005 is formed, the present invention is not limited to this. For example, a plurality of recesses may be formed in the first base material 2001 using photolithography and etching.

[0048] 7C , a metal seed layer 2100 is formed on the first surface 2000A side of the substrate 2000, including the first recess 2007 and the second recess 2009, by physical vapor deposition such as sputtering. The metal seed layer 2100 is used as a seed layer for the first metal layer 2300. The thickness of the metal seed layer 2100 is preferably 10 nm or more and 100 nm or less, from the viewpoints of enabling the first metal layer to be formed and of forming nozzle holes.

[0049] Next, as shown in FIG. 8B , an insulator 2200 (also referred to as a "first insulator") is formed on the bottom 2007b of the first recess 2007 in the metal seed layer (more specifically, at the center of the bottom 2007b). At this time, droplets 2200a that will become the insulator 2200 are ejected from a single-type electrostatic ejection inkjet nozzle 300, as shown in FIG. 8A . The size of the insulator 2200 is preferably 1 μm or more and 100 μm or less. The size of the multi-nozzle depends on the size of the insulator 2200. Therefore, it is desirable that the viscosity of the ejected droplets (ink) 2200a be 0.1 cps or more and 10,000 cps or less, and preferably 0.5 cps or more and 1,000 cps or less. Having the above-mentioned viscosity makes it easier to control the size of the droplets 2200a. It is also desirable to adjust the amount of droplets ejected. This allows the size of the nozzle opening to be adjusted.

[0050] In this embodiment, the material of the droplets is not particularly limited as long as it is an insulating material. In this example, polyimide resin (polyimide varnish), solder resist, photosensitive resin, etc. may be used as the insulating material. Furthermore, the material of the droplets may not only be an insulating material but also a semiconductor material.

[0051] Next, as shown in FIG. 8C , a first metal layer 2300 is formed on the exposed portion of the metal seed layer 2100. The first metal layer 2300 is formed by electrolytic casting (plating). The thickness of the first metal layer 2300 is preferably 1 μm or more and 10 μm or less. At this time, the first metal layer 2300 is formed on the portion of the first recess 2007 where the metal seed layer 2100 is exposed, and the first metal layer 2300 is not formed on the portion where the insulator 2200 is formed. Meanwhile, the first metal layer 2300 is formed over the entire second recess 2009.

[0052] Next, as shown in FIG. 10A , an insulator 2400 (also referred to as a "second insulator") is formed on the first metal layer 2300 and the insulator 2200 in a portion corresponding to the droplet discharge nozzle 153. First, as shown in FIG. 9A , an insulating layer 2400a is formed on the first metal layer 2300 and the insulator 2200. The insulating layer 2400a contains a resin material. There are no particular limitations on the method for forming the insulating layer 2400a, but from the perspective of forming the second metal layer 2500 to a thickness that is easy to handle, it is desirable to form it by a coating method (specifically, a spin coating method). Alternatively, the insulating layer 2400a may be formed by applying a film-like resin.

[0053] The insulating layer 2400a may include a photosensitive material. In this case, the insulator 2400 can be formed without forming a resist mask.

[0054] Next, as shown in FIG. 9B , a resist mask 2450 is formed on the insulating layer 2400a in a portion corresponding to the droplet ejection nozzle 153 (tip portion 153a). The resist mask 2450 may be formed by photolithography. Alternatively, the resist mask 2450 may be formed by electrostatic ejection inkjet printing. In this case, the resist mask 2450 can be formed without using a photomask, thereby reducing manufacturing costs. After the resist mask 2450 is formed, as shown in FIG. 10A , the exposed portions of the insulating layer 2400a are removed by etching until the first metal layer 2300 is exposed, thereby forming the insulator 2400.

[0055] 10B , a second metal layer 2500 is formed on the exposed portion of the first metal layer 2300. The second metal layer 2500 is made of the same material as the first metal layer 2300. The second metal layer 2500 is formed by electrolytic casting (plating). From the viewpoint of ease of handling of the multi-nozzle head, it is desirable that the thickness of the second metal layer 2500 be 10 μm or more and 100 μm or less.

[0056] 11A, the resist mask 2450 and the insulator 2400 are removed by a stripping method using a chemical solution such as an organic solvent, or by an etching method.

[0057] Next, as shown in FIG. 11B , the insulator 2400 and the metal seed layer 2100 present below (overlapping) the insulator 2400 are removed. The insulator 2400 may be removed by a stripping method using a chemical solution such as an organic solvent, or by an etching method. The metal seed layer 2100 may also be removed by an etching method. In this example, the metal seed layer 2100 is removed by a wet etching method. If the metal seed layer is nickel, it can be removed using a solution containing hydrogen peroxide. In this case, even if the metal seed layer 2100, the first metal layer 2300, and the second metal layer 2500 are made of the same material, the thickness of the metal seed layer 2100 is much thinner than the thicknesses of the first metal layer 2300 and the second metal layer 2500. Therefore, the variation in the thicknesses of the first metal layer 2300 and the second metal layer 2500 is small, and therefore the impact on the shape of the multi-nozzle head 150 is minimal. This results in the formation of a portion corresponding to the nozzle opening 153ao. By using the wet etching method, it is possible to remove the metal seed layer 2100 and clean the nozzle opening 153ao at the same time.

[0058] Finally, the substrate 2000 (second substrate 2005) is treated to be removed (released) from the metal seed layer 2100. In this manner, the multi-nozzle head 150 can be manufactured.

[0059] In the above, when the first metal layer 230 and the second metal layer 2500 are formed on the substrate 2000 using electrolytic casting, the electric field tends to become non-uniform in the edge regions of the substrate 2000. However, in the present embodiment, the edge regions of the substrate 2000 are regions where pseudo-nozzles are formed. Therefore, the electric field in the region where the droplet discharge nozzle 153 is formed becomes uniform. This makes it possible to make the shape of the droplet discharge nozzle 153, and further the opening shape of the tip 153a, uniform.

[0060] In this embodiment, the electrostatic inkjet method is used to uniformly form the small-sized insulator 2200 in the portion corresponding to the nozzle opening 153ao. At this time, the insulator and the metal seed layer are removed, thereby enabling the formation of a plurality of nozzle openings in a stable and uniform manner.

[0061] Therefore, by using this embodiment, it is possible to provide a method for manufacturing a multi-nozzle head that can stably form nozzle openings. Furthermore, by using the multi-nozzle head of this embodiment, it is possible to eject droplets uniformly.

[0062] Second Embodiment In this embodiment, a multi-nozzle head 150A different from that in the first embodiment will be described. Specifically, in the first embodiment, a multi-nozzle head having a spacer and an example of forming the multi-nozzle head will be described. For convenience of explanation, some appropriate members described in the first embodiment will be omitted.

[0063] FIG. 12 is a cross-sectional view of the multi-nozzle head 150A. As shown in FIG. 12, the multi-nozzle head 150A includes a plate portion 151, a droplet discharge nozzle portion 152 (droplet discharge nozzle 153), a pseudo-nozzle portion 154 (pseudo-nozzle 155), and a spacer 157. The spacer 157 has a columnar shape. The spacer 157 is provided on the plate portion 151 on the tip portion 153a side of the droplet discharge nozzle 153. The spacer 157 is configured to maintain a distance between the multi-nozzle head 150A and the target object 200 onto which droplets are to be discharged. By including the spacer 157, the distance between the multi-nozzle head 150A and the target object 200 is constant, thereby making it possible to uniform the potential difference when droplets are discharged. Therefore, droplets can be discharged uniformly.

[0064] The multi-nozzle head 150A is similar to the first embodiment up to the process of forming the openings 153ao. Next, the substrate 2000 is processed by etching or grinding between adjacent droplet discharge nozzles 153, between the droplet discharge nozzles 153 and the pseudo-nozzles 155, and between adjacent pseudo-nozzles 155, to form spacers 157. In this embodiment, the spacers 157 can be formed by processing the substrate 2000 of the first embodiment, which simplifies the manufacture of the multi-nozzle head 150A.

[0065] Third Embodiment In this embodiment, a multi-nozzle head 150B different from that in the first embodiment will be described. Specifically, in the first embodiment, a multi-nozzle head having a spacer and a flat electrode bonded to the spacer will be described. For convenience of explanation, some of the appropriate members described in the first and second embodiments will be omitted.

[0066] FIG. 13 is a cross-sectional view of the multi-nozzle head 150B. As shown in FIG. 13, the multi-nozzle head 150B has an electrode 159 in addition to a plate portion 151, a droplet discharge nozzle portion 152 (droplet discharge nozzle 153), a pseudo-nozzle portion 154 (pseudo-nozzle 155), and a spacer 157. The electrode 159 is provided to face the droplet discharge nozzle 153 and correspond to the shape of the spacer 157. In this example, the electrode 159 may be provided in a flat plate shape. In this case, the electrode 159 is provided by joining the side opposite to the side of the spacer 157 that contacts the plate portion. The electrode 159 has an opening 159o at a position corresponding to the tip portion 153a (opening 153ao) of the droplet discharge nozzle 153. A conductive material is used for the electrode 159.

[0067] In this embodiment, the distance between the droplet discharge nozzle 153 and the electrode 159 is constant. This allows a constant voltage to be applied between the droplet discharge nozzle 153 and the electrode 159. This allows droplets to be discharged uniformly onto the target object 200.

[0068] In addition, although the electrode 159 is provided in a flat plate shape in this embodiment, the present invention is not limited to this. The spacer 157 and the electrode 159 may be formed as a single unit. In this case, the spacer 157 and the plate portion 151 of the multi-nozzle head 150B may be joined together.

[0069] The shape of the electrode 159 may also be different. As shown in FIG. 14 , the multi-nozzle head 150C includes a spacer 157C and an electrode 159C in addition to the plate portion 151, the droplet discharge nozzle 153, and the pseudo nozzle 155. The spacer 157C includes a pillar portion 157Ca and a flat portion 157Cb. The pillar portion 157Ca has a pillar shape. The flat portion 157Cb has a flat plate shape. One side of the pillar portion 157Ca contacts the plate portion 151. The other side of the pillar portion 157Ca contacts the flat portion 157Cb. In this case, the electrode 159C may be provided in contact with the flat portion 157Cb of the spacer 157C so as to face the droplet discharge nozzle 153 (tip portion 153a). The electrode 159C may be provided in a ring shape. The opening 153ao of the tip 153a of the droplet discharge nozzle 153, the opening 159Co of the electrode 159C, and the opening 157Co of the plate portion 157Cb are provided to correspond to each other. The electrode 159C may be provided in contact with the underside of the plate portion 157Cb of the spacer 157C.

[0070] (Modifications) Within the scope of the concept of the present invention, a person skilled in the art may conceive of various modifications and alterations, and it is understood that these modifications and alterations also fall within the scope of the present invention. For example, to the above-described embodiments, a person skilled in the art may appropriately add or delete components, combine or modify the designs of the embodiments, or add or omit processing or change conditions, all of which are included within the scope of the present invention as long as they maintain the gist of the present invention.

[0071] In the first embodiment of the present invention, an example was shown in which droplets 2200a that become insulators 2200 are ejected from a single electrostatic ejection inkjet nozzle, but the present invention is not limited to this. For example, after manufacturing an initial multi-nozzle head, the second and subsequent multi-nozzle heads may be manufactured using the first multi-nozzle head. This allows droplets to be ejected from each nozzle of the multi-nozzle head, thereby increasing the manufacturing speed of the multi-nozzle heads.

[0072] Furthermore, when discharging droplets that will become the insulator 2200 in the first embodiment of the present invention, an imaging unit (camera) may be moved together with the electrostatic discharge inkjet nozzle. This allows the droplet discharge position to be imaged in advance, and the position of the electrostatic discharge inkjet nozzle to be corrected if the droplet discharge position is misaligned.

[0073] Furthermore, the state of droplet discharge may be inspected by an imaging unit after droplet discharge into the first recess 2007. In this case, the first droplet may be removed from the location where a discharge defect occurs, and droplets may be discharged again.

[0074] In one embodiment of the present invention, the insulator 2400 is not limited to a resin material, but may be an inorganic insulating material, for example.

[0075] In the first embodiment of the present invention, the metal seed layer 2100 is removed by wet etching, but the present invention is not limited to this. For example, depending on the material of the metal seed layer, the metal seed layer may be removed by dry etching. Furthermore, the metal seed layer may be removed by lift-off when removing the insulator 2200. This simplifies the manufacturing process of the multi-nozzle head.

[0076] 100... droplet ejection device, 110... control unit, 115... memory unit, 120... power supply unit, 130... drive unit, 140... droplet ejection unit, 145... ink tank, 150... multi-nozzle head, 150A... multi-nozzle head, 150B... multi-nozzle head, 150C... multi-nozzle head, 151... plate portion, 151a... lower surface, 151o... through hole, 152... droplet ejection nozzle portion, 153... droplet ejection nozzle, 153a... tip portion, 153ao... opening portion, 154... pseudo-nozzle portion, 155... pseudo-nozzle, 155a... tip portion, 155L... left pseudo-nozzle, 155-L1 to 5... pseudo-nozzle, 155R... right pseudo-nozzle, 155-R1 to 5... pseudo-nozzle, 1 57...spacer, 157C...spacer, 157Ca...column portion, 157Cb...flat portion, 157Co...opening, 159...electrode, 159C...electrode, 159Co...opening, 159o...opening, 160...object holder, 200...object, 300...electrostatic ejection type ink jet nozzle, 2000...substrate, 2000A...first surface (upper surface), 2000B...second surface (lower surface), 2001...first substrate, 2005...second substrate, 2007...first recess, 2007b...bottom, 2009...second recess, 2100...metal seed layer, 2200...insulator, 2200a...droplet, 2300...first metal layer, 2400...insulator, 2400a...insulating layer, 2450...resist mass 2500...second metal layer

Claims

1. A method for manufacturing a multi-nozzle head, comprising: preparing a substrate having an upper surface and a lower surface opposite the upper surface, the substrate having a plurality of recesses on the upper surface; forming a metal seed layer on the upper surface and on the plurality of recesses of the substrate; forming a first insulator on bottoms of the plurality of recesses in the metal seed layer using an electrostatic discharge inkjet method; forming a first metal layer on exposed portions of the metal seed layer; forming a second insulator on the metal seed layer and the first insulator; forming a second metal layer on exposed portions of the first metal layer; removing the second insulator, the first insulator, and the metal seed layer overlapping the first insulator to form a nozzle opening; and processing the substrate.

2. The method for manufacturing a multi-nozzle head according to claim 1, wherein the size of the first insulator is 1 μm or more and 100 μm or less.

3. The method for manufacturing a multi-nozzle head according to claim 1, wherein a mask formed by an electrostatic ejection type inkjet method is used when forming the second insulator.

4. The method for manufacturing a multi-nozzle head according to claim 1, wherein the diameter of the nozzle opening is adjusted according to the amount of the first insulator to be discharged.

5. The method for manufacturing a multi-nozzle head according to claim 1, wherein the metal seed layer overlapping the first insulator is removed by etching.

6. The method for manufacturing a multi-nozzle head according to claim 1, wherein the metal seed layer overlapping the first insulator is removed using a wet etching method.

7. The method for manufacturing a multi-nozzle head according to claim 1, wherein the metal seed layer overlapping the first insulator is removed using a lift-off method.

8. The method for manufacturing a multi-nozzle head according to claim 1, wherein the thickness of the metal seed layer is 10 nm or more and 100 nm or less.

9. A method for manufacturing a multi-nozzle head according to claim 1, wherein the thickness of the first metal layer is 1 μm or more and 10 μm or less, and the thickness of the second metal layer is 10 μm or more and 100 μm or less.

10. The method for manufacturing a multi-nozzle head according to claim 1, further comprising processing the base material to form a spacer that maintains a distance from the discharge target.

11. The method for manufacturing a multi-nozzle head according to claim 10, further comprising forming an electrode that is in contact with a part of the spacer and has an opening in a portion that corresponds to the nozzle opening.

12. A multi-nozzle head comprising: a plate portion having through holes; a droplet discharge nozzle portion including a plurality of droplet discharge nozzles provided corresponding to the through holes of said plate portion and discharging droplets by an electrostatic discharge method; a pseudo-nozzle portion provided on said plate portion around said droplet discharge nozzle portion and including a plurality of pseudo-nozzles with closed tips; and a spacer provided on said plate portion on the tip side of said droplet discharge nozzles and configured to maintain a distance from an object onto which the droplets are discharged.

13. A multi-nozzle head according to claim 12, wherein the spacer has a pillar portion in contact with the plate portion, and a flat portion provided opposite the plate portion and in contact with the pillar portion.

14. The multi-nozzle head according to claim 12, further comprising an electrode provided on the spacer so as to face the droplet ejection nozzle.

15. A droplet ejection device comprising the multi-nozzle head according to claim 12.

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