TW201714757A - Electronic device, liquid ejecting head, liquid ejecting apparatus, and method of manufacturing electronic device - Google Patents

Abstract

An electronic device on which a plurality of substrates are stacked is provided. At least one substrate among the plurality of substrates is a silicon substrate of which a thickness is equal to or greater than 300 [[mu]m]. A through hole that penetrates the substrate in a thickness direction is formed on the substrate. A value of a ratio (t/D) of the thickness (t) of the substrate to a minimum internal dimension (D) of one opening of the through hole is equal to or greater than 10.

Description

Electronic device, liquid ejection head, liquid ejection device, and manufacturing method of electronic device

The present invention relates to an electronic device, a liquid ejecting head, a liquid ejecting apparatus, and a method of manufacturing an electronic device, which are used for ejecting a liquid such as an ink jet recording head, and the like, and more particularly to a substrate including a through hole. The electronic device, the liquid ejection head, the liquid ejection device, and the manufacturing method of the electronic device.

The electronic device includes an actuator such as a piezoelectric element, an electronic circuit, or the like on the substrate, and can be applied to various liquid ejecting devices, vibration sensors, and the like. For example, in the liquid ejecting apparatus, various liquids are ejected (sprayed) from the liquid ejecting head by the electronic device. Although the liquid ejecting apparatus includes an image recording apparatus such as an ink jet printer or an ink jet type plotter, it is also applied to, for example, a display manufacturing apparatus for manufacturing a color filter such as a liquid crystal display. An electrode forming device for an electrode such as an EL (Electro Luminescence) display or an FED (Field Emission Display) (surface emitting display), or a wafer manufacturing device for manufacturing a biochip (biochemical element). Further, liquid ink is ejected from the recording head for the image recording apparatus, and colors of R (Red: red), G (Green: green), and B (Blue: blue) are ejected from the color material ejecting head for the display manufacturing apparatus. A solution of the material. Further, a liquid material is ejected from the electrode material ejecting head for the electrode forming apparatus, and a solution of the organic matter of the living body is sprayed on the bioorganic material ejecting head for the wafer manufacturing apparatus.

The above-mentioned liquid ejection head is provided with a nozzle plate for opening a nozzle, and is connected to the spray nozzle. a pressure chamber of the pressure chamber of the nozzle forms a substrate, a communication substrate for connecting a communication port for connecting the nozzle to the pressure chamber, a flow path for supplying a liquid to the pressure chamber, a piezoelectric element for causing a pressure fluctuation of the liquid in the pressure chamber, and A plurality of layers of a substrate such as a relay substrate in which the piezoelectric elements are spaced apart from each other. Further, the piezoelectric element described above is driven by a drive signal supplied from a drive circuit (also referred to as a drive IC or a driver IC). As the substrate constituting the liquid ejecting head, a single crystal germanium substrate (hereinafter, simply referred to as a germanium substrate) is preferably used. Further, the ruthenium substrate is formed with a through hole that functions as a flow path through which the liquid flows, or a through-wiring in which an electrode material is embedded as an electronic component on one surface side of the substrate and an electronic component on the other surface side. A through hole that functions as a connecting hole or a through hole. As a method of forming such a through hole in the ruthenium substrate, for example, a method of forming a through hole in the ruthenium substrate, first forming a reserved hole (preparation hole) by laser light, and then by arranging the reservation The hole is expanded by anisotropic etching to form a through hole (for example, see Patent Document 1).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] International Publication No. 2000/50198

However, in recent years, with the demand for miniaturization or high resolution of the liquid ejecting head, the size of the opening of the through hole, that is, the size of the opening in the direction parallel to the surface of the substrate is reduced, and a higher aspect ratio is formed. The need for through holes. Further, since such a through hole is formed at a higher density, the pitch (the distance between the centers of the openings) of the adjacent through holes is also extremely small. In the case of the above-described Patent Document 1, when the through hole (preparation hole) is opened by the laser on the substrate, the through hole has a shape in which the incident side of the laser light is wide and the outlet side is narrow, so that the substrate is The thickness or the formation pitch of the through holes has a problem that the openings on the inlet side interfere with each other to collapse the shape of the through holes. As described above, the high aspect ratio of the through holes cannot be sufficiently dealt with by the method of forming the through holes.

The present invention has been made in view of such a situation, and its object is to provide an alternative A method for manufacturing a through hole having a higher aspect ratio, a miniaturized electronic device, a liquid ejection head, a liquid ejection device, and an electronic device with high precision.

In order to achieve the above object, an electronic device according to the present invention is characterized in that a plurality of substrates are laminated, and at least one of the plurality of substrates is a substrate having a thickness of 300 [μm] or more; a through hole penetrating through a thickness direction of the substrate; a ratio of a thickness (t) of the substrate to a minimum inner dimension (D) of the opening of the through hole (t/D) 10 or more.

According to the above configuration, the through hole including the value (t/D) of the ratio (t/D) of the thickness (t) of one substrate to the minimum inner dimension (D) of one opening (the value of the aspect ratio) is 10 or more. A substrate having a diameter of 300 [μm] or more forms a through hole having a smaller inner dimension and a smaller opening at a higher density, thereby contributing to miniaturization of the electronic device.

In the above configuration, it is preferable that the inner wall surface of the through hole is periodically formed with irregularities along a central axis of the through hole, and the bottom portion of the concave portion of the inner wall surface of the through hole is formed by the bottom portion The difference between the inner circumference of the inner wall surface and the inner circumference of the inner wall surface formed by the apex of the convex portion of the uneven portion is larger in the region on the other opening side than in the region on the other opening side.

According to this configuration, the shape of the concavities and convexities is, for example, a retaining member for the filling material filled in the through holes, and the filler is prevented from falling off from the through holes. Thereby, there is no need for an adhesion layer in which the inner surface of the through hole is in close contact with the filler. Further, the difference in the size of the inner and outer surfaces of the region on the opening side of the inner wall surface of the through hole (the difference between the inner circumference of the inner wall surface formed by the bottom portion of the concave portion and the inner circumference of the convex portion) is a thickness of the protective film of the area of the opening side when compared to an opening area of the side ', the other side of the opening in the region of the difference of the size of the irregularities is smaller, and the through-hole in the manufacturing comprising the step of dry etching It becomes more uniform, so that the inner wall surface damage in the region of the position due to the repetition of the dry etching step can be reduced. As a result, the shape of the opening of one of the through holes formed is suppressed from expanding or collapsing more than predetermined.

In the above configuration, it is preferable that the minimum inner dimension of the through hole is 25 [μm] or less.

According to this configuration, the through holes can be arranged at a higher density. Thereby, further miniaturization of the electronic device can be achieved.

In the above configuration, preferably, the through hole includes a main hole including the one opening and a sub hole including another opening; and an inner wall surface of the sub hole is inclined with respect to a surface of the substrate, and the inner hole is inclined The cross-sectional area of the sub-hole orthogonal to the surface in the thickness direction of the substrate gradually decreases from the other opening side toward the main hole side.

According to this configuration, the main hole can be formed by repeating the dry etching step in the production of the through hole, and the sub hole can be formed by laser processing. Thereby, the shape of the other opening of the through hole is suppressed from expanding or collapsing more than predetermined.

In the above configuration, it is preferable that the through hole has a polygonal shape and a minimum length of the polygon is 40 [μm] or less.

Further, in this configuration, it is preferable that the inner wall surface of the through hole includes a crystal surface of the ruthenium substrate including the side of the polygon.

According to this configuration, since the inner wall surface of the through hole includes the crystal surface of the ruthenium substrate, the size and shape of each through hole can be made uniform in an electronic device having a plurality of through holes.

In the above configuration, the through hole is preferably a through wiring in which the conductor is disposed, and the through wiring is disposed on the first electronic component disposed on one surface side of the one substrate and on the other substrate The second electronic component on one side is turned on.

Further, in the above configuration, the through hole may constitute at least a part of a flow path through which a fluid flows.

Further, the liquid ejecting head according to the present invention includes the electronic device, and includes an actuator substrate as the first electronic component, wherein a pressure fluctuation of a liquid in a pressure chamber is caused to communicate with the pressure chamber. An actuator that ejects a liquid from the nozzle; and a drive circuit that is the second electronic component is driven by the actuator; and the one substrate is disposed between the actuator substrate and the drive circuit; The wiring electrically connects the actuator to the drive circuit.

According to the configuration described above, since the through wiring can be disposed at a higher density, it is possible to contribute to the miniaturization of the liquid discharge head in accordance with the increase in density of other wirings that are electrically connected to the through wiring.

Further, the liquid ejecting head according to the present invention includes the electronic device, comprising: a nozzle forming substrate formed with a nozzle for ejecting a liquid; and a pressure chamber forming substrate having a pressure chamber connected to the nozzle; And causing a pressure fluctuation of the liquid in the pressure chamber; wherein the one substrate is disposed between the nozzle forming substrate and the pressure chamber forming substrate; and the one substrate is formed with the nozzle communicating with the pressure chamber Through hole.

According to the above configuration, since the through holes can be disposed at a higher density, the density of the nozzles or other flow paths can be increased, which contributes to downsizing of the liquid ejecting head.

The liquid ejecting apparatus of the present invention is characterized by comprising the above liquid ejecting head.

Further, a method of manufacturing an electronic device according to the present invention is a method of manufacturing an electronic device in which at least one of a plurality of substrates is formed with a through hole penetrating through a thickness direction of the substrate, and is characterized in that the method is formed as follows Through hole: a mask forming step of forming a mask on a surface of the substrate; a main hole forming step of sequentially performing a dry etching step of removing a portion of the one substrate from a surface side of the substrate via the mask, and forming a protective film on the exposed portion of the substrate formed by dry etching a protective film forming step of forming a main hole that does not penetrate the thickness direction of the substrate; and a laser processing step of irradiating the laser to the predetermined portion of the opening of the other surface of the one of the through holes A sub-hole communicating with the main hole is formed.

According to the above manufacturing method, since the main hole is formed by repeating the dry etching step and the protective film forming step, and the predetermined portion of the opening of the other surface of one substrate is formed by the laser processing to form the through hole, the precision can be made more accurate. The ground forms a through hole of a higher aspect ratio.

In the above manufacturing method, preferably, the dry etching step includes an isotropic dry etching step; and the isotropic dry etching step has a plurality of etching conditions different in processing time per one time; in the main hole, The processing time per one time of the etching conditions for forming the side of the sub-hole is longer than the processing time per one time of the etching conditions on the one side of the one substrate.

According to the above manufacturing method, the abnormality in which the opening shape of one of the through holes is more enlarged or collapsed than the predetermined one is suppressed. That is, the processing time per one time of the etching condition in which the side of the sub-hole is formed in the main hole is longer than the processing time per one time of the etching side of one of the main holes, in other words, from one side of a substrate In the initial stage from the side to the thickness direction of the substrate (the stage in which one side of the substrate is formed in the main hole), the processing time per one time of the isotropic dry etching step is shorter than the subsequent (formation in the main hole) The step of forming the side of the hole) is performed for each processing time of the isotropic dry etching step, so that the difference in size within the unevenness of the inner wall surface of the main hole formed in the isotropic dry etching step is smaller than that in the subsequent process The difference in size within the concavities and convexities of the inner wall surface of the main hole formed by the isotropic dry etching step. Therefore, the film thickness of the protective film becomes more uniform, and the internal surface damage on the open side of one of the main holes due to the repetition of the dry etching step can be reduced.

Further, in the above-described manufacturing method, in the mask forming step, the minimum inner dimension of the opening of the mask which is intended to form the through hole is 25 [μm] or less.

Preferably, the manufacturing method further includes an anisotropic etching step of exposing the through hole to an anisotropic etching liquid having a different etching rate to a crystal plane of the germanium substrate, and performing an inner wall of the through hole Anisotropic etching.

According to the above manufacturing method, the unevenness of the inner wall surface of the through hole is removed by the anisotropic etching, and finally, the through hole having the crystal surface of the tantalum substrate as the inner wall surface is formed. Thereby, the through hole of a higher aspect ratio can be obtained with good dimensional and shape precision.

1‧‧‧Printer

2‧‧‧Recording media

3‧‧‧record head

4‧‧‧ bracket

5‧‧‧ bracket moving mechanism

6‧‧‧Transportation agency

7‧‧‧Ink 匣

8‧‧‧Time belt

9‧‧‧ pulse motor

10‧‧‧guides

14‧‧‧Electronic devices

16‧‧‧record head box

17‧‧‧ accommodating space

18‧‧‧ Liquid introduction route

21‧‧‧Nozzle plate

22‧‧‧Nozzles

24‧‧‧Connected substrate

24'‧‧‧Substrate

25‧‧‧Common liquid room

25a‧‧‧1st liquid chamber

25b‧‧‧Second liquid chamber

26‧‧‧ individual connections

27‧‧‧ nozzle connection

29‧‧‧ Pressure chamber forming substrate

30‧‧‧ Pressure chamber

31‧‧‧Vibration plate

32‧‧‧Piezoelectric components

33‧‧‧Relay substrate

34‧‧‧Drive IC

37‧‧‧Drive wiring

38‧‧‧Upper surface wiring

40‧‧‧Bump electrode

40a‧‧‧Resin Department

40b‧‧‧electrode layer

41‧‧‧IC electrodes

43‧‧‧ Joining resin

45‧‧‧through wiring

47‧‧‧ Lower surface side wiring

48‧‧‧Substrate through hole

50‧‧‧Conductor

51‧‧‧ main hole

51a‧‧‧1st hole

51b‧‧‧2nd hole

52‧‧‧Sub-hole

53‧‧‧ inside the bump

53a‧‧‧ convex ring

53b‧‧‧ concave ring

54‧‧‧Oxide film

55‧‧‧Mask opening

55a‧‧‧Mask opening

55b‧‧‧Mask opening

56‧‧‧mask layer

56a‧‧‧ mask

56b‧‧‧ mask

57‧‧‧1st recess

57a‧‧‧1st recess

57b‧‧‧1st recess

58‧‧‧Protective film

62‧‧‧ inner wall of the secondary hole

64‧‧‧floor

65‧‧‧Reserved holes

66‧‧‧ inside the bump

66a‧‧‧ convex ring

66b‧‧‧ concave ring

67‧‧‧2nd recess

68‧‧‧ main hole

69‧‧‧1st hole

70‧‧‧2nd hole

71‧‧‧Sub-hole

72‧‧‧Ink resistant film

A‧‧‧ area

Ax‧‧‧ central axis

D1‧‧‧Minimum inner dimensions

D2‧‧‧Minimum inner size

T1‧‧‧ thickness

T2‧‧‧ thickness

Fig. 1 is a perspective view showing the internal structure of the printer.

Fig. 2 is a cross-sectional view showing the configuration of a recording head.

Fig. 3 is a cross-sectional view showing the main part of the vicinity of the nozzle communication port of the recording head.

Fig. 4 is a plan view showing the vicinity of a nozzle communication port connecting the substrates.

Fig. 5 is a cross-sectional view showing the main part of the vicinity of the through wiring of the recording head.

Figure 6 is an enlarged view of a region A of Figure 5.

Fig. 7 is a view showing the steps of the step of forming the nozzle communication port.

Fig. 8 is a view showing the steps of the step of forming the nozzle communication port.

Fig. 9 is a view showing the steps of forming a nozzle communication port.

Fig. 10 is a view showing the steps of the step of forming the nozzle communication port.

Figure 11 is a flow chart showing the steps of forming the nozzle communication port.

Figure 12 is a flow chart showing the steps of forming the nozzle communication port.

Figure 13 is a flow chart showing the steps of forming the nozzle communication port.

Fig. 14 is a view showing the steps of the step of forming the nozzle communication port.

Fig. 15 is a view showing the steps of the step of forming the nozzle communication port.

Fig. 16 is a view showing the steps of the step of forming the nozzle communication port.

Figure 17 is a flow chart showing the steps of forming the nozzle communication port.

Hereinafter, embodiments for carrying out the invention will be described with reference to the accompanying drawings. In the following description, the preferred embodiments of the present invention are variously limited, but the scope of the present invention is not limited to the following description unless otherwise specified. The same. In the following, an ink jet type recording head (hereinafter referred to as a recording head) which is one type of liquid ejecting head including the electronic apparatus of the present invention, and an ink jet type printing apparatus which is one type of liquid ejecting apparatus in which the recording head is mounted (hereinafter, referred to as a printer) will be described as an example.

The configuration of the printer 1 will be described with reference to Fig. 1 . The printer 1 is a device that records ink or the like on a surface of a recording medium 2 such as recording paper to record an image or the like. The printer 1 includes a recording head 3, a carriage 4 on which the recording head 3 is mounted, a carriage moving mechanism 5 for moving the carriage 4 in the main scanning direction, and a conveying mechanism 6 for conveying the recording medium 2 in the sub-scanning direction. Wait. Here, the ink described above is stored in the ink cartridge 7 as a liquid supply source. The ink cartridge 7 supplies the ink stored therein to the recording head 3 by being attached to the carriage 4. Alternatively, the ink cartridge may be disposed on the main body side of the printer and supplied from the ink cartridge to the recording head through the ink supply tube.

The above-described carriage moving mechanism 5 includes a timing belt 8. Further, the timing belt 8 is driven by a pulse motor 9 such as a DC motor. Therefore, as soon as the pulse motor 9 is actuated, the carriage 4 is guided by the guide bar 10 mounted on the printer 1 to reciprocate in the main scanning direction (the width direction of the recording medium 2). The position of the carriage 4 in the main scanning direction is detected by a linear encoder (not shown) which is one of the position information detecting means, and is grasped by the control unit of the printer 1.

Next, the recording head 3 will be described. Fig. 2 is a cross-sectional view showing the configuration of the recording head 3. Fig. 3 is an enlarged view of a main portion showing the configuration of the vicinity of the nozzle communication port 27 of the recording head 3. 4 is a plan view of the vicinity of the nozzle communication port 27 of the communication substrate 24. Moreover, FIG. 5 is an enlarged view of a main portion of the vicinity of the through wiring 45 of the relay substrate 33 of the recording head 3. In addition, Figure 6 is Figure 5 A magnified view of area A. In addition, the scale ratio of each figure is different from the real thing for convenience of illustration. As shown in FIG. 2, the recording head 3 of the present embodiment is configured by attaching an electronic device 14 in which a plurality of layers of substrates or the like are laminated to the head cartridge 16. Each of the substrates is formed by sequentially laminating the nozzle plate 21, the communication substrate 24 (one of the substrates of the present invention), and the pressure chamber forming substrate 29 (actuator substrate), and bonding them by an adhesive or the like. Further, on the surface of the pressure chamber forming substrate 29 opposite to the side of the communication substrate 24, the diaphragm 31, the piezoelectric element 32 (corresponding to the actuator and the first electronic component of the present invention), and the relay substrate (intermediate board) are laminated. 33 and the drive IC 34 (corresponding to the second electronic component and the drive circuit of the present invention) constitute the electronic device 14 of the present invention. In addition, for convenience, the lamination direction of each member will be described as the vertical direction.

The recording head cartridge 16 is a box-shaped member made of synthetic resin, and a liquid introduction path 18 for supplying ink to a common liquid chamber 25 to be described later is formed inside. The liquid introduction path 18 and the common liquid chamber 25 are spaces for storing ink which are common to a plurality of pressure chambers 30 arranged side by side. Further, a accommodating space 17 is formed at a position where the recording head cartridge 16 is displaced from the liquid introduction path 18. The pressure chamber forming substrate 29, the relay substrate 33, the drive IC 34, and the like in the electronic device 14 are housed in the accommodating space 17.

The communication board 24 of the present embodiment is a sheet material made of tantalum having a thickness of 400 [μm], and in the present embodiment, a single crystal germanium substrate having a crystal plane orientation of the surface (upper surface and lower surface) of (110) plane. Production. As shown in FIG. 2, in the interconnecting substrate 24, a common liquid chamber 25 is formed by anisotropic wet etching, which communicates with the liquid introduction path 18, and stores common ink with each pressure chamber 30; and an individual communication port. 26, the ink from the liquid introduction path 18 is individually supplied to each pressure chamber 30 via the common liquid chamber 25. The common liquid chamber 25 is an empty portion along the strip in the nozzle row direction, and is formed in two rows corresponding to the row of the pressure chambers 30 in which two rows are arranged side by side. The common liquid chamber 25 includes a first liquid chamber 25a that penetrates the thickness direction of the communication substrate 24, and a recessed direction from the lower surface side toward the upper surface side of the communication substrate 24 to the thickness direction of the communication substrate 24. The second liquid chamber 25b formed in a state in which the thin plate portion remains on the upper surface side. individual The communication port 26 is formed in a plurality of thin plate portions of the second liquid chamber 25b in correspondence with the pressure chamber 30 along the direction in which the pressure chambers 30 are arranged side by side. The individual communication port 26 communicates with the end portion on the one side in the longitudinal direction of the corresponding pressure chamber 30 in a state where the communication substrate 24 is joined to the pressure chamber forming substrate 29.

Further, at a position corresponding to each of the nozzles 22 of the communication board 24, a nozzle communication port 27 (one of the through holes of the present invention) penetrating the thickness direction of the communication board 24 is formed. That is, the nozzle communication port 27 is formed in plural in the nozzle row direction corresponding to each nozzle 22 (refer to FIG. 4). The nozzle communication port 27 is interposed between the pressure chamber 30 and the nozzle 22 to form a portion of the ink flow path (corresponding to a flow path through which the fluid is supplied). The nozzle communication port 27 of the present embodiment communicates with the end portion of the other side (the side opposite to the individual communication port 26) in the longitudinal direction of the corresponding pressure chamber 30 in a state where the communication substrate 24 is joined to the pressure chamber forming substrate 29. The nozzle communication port 27 is a so-called Bosch process in which a dry etching step is alternately repeated on the communication substrate 24 of the germanium substrate, and a protective film forming step of forming a protective film on the dry etching portion is performed. After the formation of the reserved holes by laser processing, the shape of the holes is finally formed by anisotropic wet etching using an etching solution containing an aqueous solution of potassium hydroxide (KOH). Details of this point will be described later.

As described above, the shape of the nozzle communication port 27 is formed by wet etching using KOH, which is a substrate on which the upper and lower surfaces are the (110) plane, that is, the communication substrate 24. Therefore, the shape of the opening of the nozzle communication port 27 that communicates with the surface of the substrate 24 is a parallelogram shape of a polygonal shape as shown in FIG. That is, the inner wall surface of the nozzle communication port 27 is the first (111) plane intersecting the crystal plane of the crucible substrate, specifically, the (110) plane, and the intersection of the (110) plane and the first (111) plane. 2 (111) face composition. The inner wall surface of the nozzle communication port 27 including the first (111) plane forms a long side of the opening of the nozzle communication port 27, and includes a short side in which the inner wall surface of the second (111) plane forms an opening. The short side of the nozzle communication port 27 is the smallest inner dimension (D1) of the nozzle communication port 27. Further, the ratio (t1/D1) of the thickness (t1) of the thickness of the interconnecting substrate 24 to the minimum inner dimension (D1) of the opening of one of the surfaces of the communicating substrate 24 (the upper surface side and the pressure chamber forming substrate 29 side), that is, the cross direction ratio The value becomes 10 or more. Specifically, the thickness (t1) of the communication substrate 24 is 400 [μm] or more, and the minimum inner dimension (D1) of one of the nozzle communication ports 27 is 40 [μm] or less. Thereby, since the nozzle communication port 27 can be disposed at a higher density on the communication substrate 24, the density of the nozzle 22 or other flow paths can be increased, which contributes to downsizing of the recording head 3. Further, since the inner wall surface of the nozzle communication port 27 includes the crystal plane of the ruthenium substrate, the size and shape of the nozzle communication ports 27 can be made more uniform in the electronic device 14 having the plurality of nozzle communication ports 27. Thereby, the deviation of the discharge characteristics (discharge amount or flying speed) of the ink ejected from the nozzle 22 can be suppressed by the size or shape of the nozzle communication port 27. Further, the shape of the opening of the nozzle communication port 27 is not limited to a parallelogram, and may be a polygonal shape in which a fluid such as ink can flow.

The nozzle plate 21 is bonded to a substrate which is formed by twisting the lower surface of the substrate 24 (the surface opposite to the pressure chamber forming substrate 29). In the present embodiment, the nozzle plate 21 seals the opening on the lower surface side of the space of the common liquid chamber 25. Further, a plurality of nozzles 22 are formed in the nozzle plate 21 in a straight line (line shape). The plurality of nozzles 22 (nozzle rows) arranged side by side are spaced from the nozzle 22 on the one end side to the nozzle 22 on the other end side at equal intervals in the sub-scanning direction orthogonal to the main scanning direction. Settings.

The pressure chamber forming substrate 29 is made of a tantalum substrate similarly to the communicating substrate 24 or the nozzle plate 21. The substrate 29 is formed in the pressure chamber, and a plurality of spaces to be the pressure chambers 30 are arranged side by side in the nozzle row direction by anisotropic etching. The space is divided by the communication substrate 24 and the upper portion is partitioned by the vibration plate 31 to constitute the pressure chamber 30. Each of the pressure chambers 30 is formed to be elongated in a direction orthogonal to the nozzle row direction, and the end portion on one side in the longitudinal direction communicates with the individual communication port 26, and the other end portion communicates with the nozzle communication port 27.

The vibrating plate 31 is a member having an elastic film shape, and is laminated on the upper surface of the pressure chamber forming substrate 29 (the surface on the side opposite to the side of the communicating substrate 24). The vibrating plate 31 is sealed by an opening above the space of the pressure chamber 30. In other words, the upper surface of the pressure chamber 30 is partitioned by the vibrating plate 31. The portion of the vibrating plate 31 corresponding to the upper opening of the pressure chamber 30 is The displacement portion that is displaced in a direction away from or close to the nozzle 22 due to the bending deformation of the piezoelectric element 32 functions. That is, the region of the vibrating plate 31 corresponding to the upper opening of the pressure chamber 30 serves as a driving region that allows bending deformation. The volume of the pressure chamber is varied by the deformation of the drive region.

Further, the diaphragm 31 includes, for example, an elastic film containing cerium oxide (SiO ₂ ) formed on the upper surface of the pressure chamber forming substrate 29, and an insulator film containing zirconia (ZrO ₂ ) formed on the elastic film. Further, a piezoelectric element 32 is laminated on each of the regions (i.e., the driving regions) corresponding to the respective pressure chambers 30 on the insulating film (the surface of the vibrating plate 31 opposite to the pressure chamber forming substrate 29 side). The piezoelectric element 32 of the present embodiment is a piezoelectric element of a so-called bending mode. The piezoelectric element 32 is formed by, for example, laminating a lower electrode layer, a piezoelectric layer, and an upper electrode layer on the diaphragm 31. When the electric field corresponding to the potential difference between the electrodes is given between the lower electrode layer and the upper electrode layer, the piezoelectric element 32 thus configured is bent and deformed in a direction away from or close to the nozzle 22. As shown in FIG. 2, from each of the piezoelectric elements 32, the drive wiring 37 is drawn to the outside of the piezoelectric element 32 (i.e., the non-driving region deviated from the driving region). The drive wiring 37 is for applying a wiring for driving the driving signal of the piezoelectric element 32 to the piezoelectric element 32, and is extended from the piezoelectric element 32 to the end of the vibration plate 31 in a direction orthogonal to the nozzle row direction. unit.

The relay substrate 33 (one of the substrates of the present invention) is a flat substrate that is spaced apart from the diaphragm 31 (or the piezoelectric element 32). In the present embodiment, it is produced from a substrate having a surface (upper surface and lower surface) of (110) plane. A drive IC 34 that outputs a drive signal related to driving of the piezoelectric element 32 is disposed on the upper surface (surface opposite to the piezoelectric element 32 side) of the relay substrate 33. Further, on the lower surface of the relay substrate 33 (the surface on the piezoelectric element 32 side), bump electrodes 40 electrically connected to the drive wirings 37 of the respective piezoelectric elements 32 are formed. The bump electrode 40 of the present embodiment is provided so as to protrude toward the diaphragm 31 in a region of the relay substrate 33 that faces the drive wiring 37. The bump electrode 40 includes a resin portion 40a including an elastic body protruding toward the side of the vibration plate 31, and a vibration plate along the resin portion 40a. The electrode layer 40b is formed on the surface of the 31 side. The resin portion 40a of the present embodiment is formed as a ridge in the nozzle row direction on the lower surface of the relay substrate 33. Further, the electrode layer 40b corresponds to the piezoelectric elements 32 arranged side by side in the nozzle row direction, and a plurality of them are formed in the nozzle row direction. That is, the bump electrodes 40 are formed in plural numbers in the nozzle row direction corresponding to the piezoelectric elements 32. Further, the surface of the resin portion 40a and the electrode layer 40b facing the side opposite to the drive wiring 37 (the lower surface of the bump electrode 40) is oriented toward the pressure chamber forming substrate 29 in a cross-sectional view in a direction orthogonal to the nozzle row direction. It is formed by bending in an arc shape. Such a bump electrode 40 is elastically deformed by pressing an arcuate portion of the lower surface thereof against the corresponding driving wiring 37, thereby achieving conduction with the driving wiring 37.

Further, as shown in FIG. 2, the IC electrode 41 of the drive IC 34 is connected to the upper surface of the relay substrate 33, and the signal upper surface side wiring 38 from the drive IC 34 is formed. The upper surface side wiring 38 is formed in a plurality of strips in the nozzle row direction corresponding to the piezoelectric element 32. The upper surface side wiring 38 extends from the end portion on the side connected to the IC electrode 41 toward the center side of the relay substrate 33 in a direction orthogonal to the nozzle row. The end portion on the opposite side of the upper surface side wiring 38 is connected to the lower surface side wiring 47 formed on the lower surface of the relay substrate 33 via the through wiring 45.

As shown in FIG. 5 and FIG. 6, the through wiring 45 is a wiring that relays between the lower surface and the upper surface of the relay substrate 33, and includes a substrate through-hole 48 that penetrates the relay substrate 33 in the thickness direction. And a conductor portion 50 (one of a filler material) including a conductor such as a metal formed at a central portion of the substrate through-hole 48. The substrate through hole 48 of the present embodiment has a main hole 51 and a sub hole 52. The main hole 51 occupies most of the substrate through-hole 48, and the upper surface of the relay substrate 33 (one surface of the relay substrate 33) is formed slightly closer to the lower surface of the relay substrate 33 (the other surface of the relay substrate 33). The position of the surface. In other words, the main hole 51 is formed in a state in which the thickness direction of the relay substrate 33 is not penetrated. Further, the main hole 51 has a first hole portion 51a formed in a specific range from the opening on the upper surface side to the thickness direction of the substrate, and a second hole portion 51b formed in the range from the first hole portion 51a to the sub-hole 52. .

Here, a corrugated concave-convex inner surface 53 is formed on the inner wall surface of the main hole 51 along the central axis (imaginary central axis) ax of the substrate through-hole 48. In other words, the convex ring 53a (corresponding to the convex portion of the present invention) protruding from the inner wall surface of the substrate through-hole 48 toward the central axis side is alternately arranged along the central axis ax, and is formed between the adjacent convex rings 53a. The concave ring 53b (corresponding to the concave portion of the present invention) has a folded (corrugated, telescopic) concavity and convexity on the inner wall surface of the substrate through-hole 48. In other words, the inner and outer walls of the substrate through-hole 48 are periodically irregularly repeated along the central axis ax to form the concavo-convex inner surface 53. Such a concavo-convex shape is also referred to as a fan shape in association with processing (described later) of the substrate through-hole 48. The uneven inner surface 53 has a difference in inner dimensions of the inner surface of the first hole portion 51a (corresponding to a region on the opening side of the present invention), that is, a bottom portion (and a center) of the concave portion of the inner surface 53 of the uneven portion The inner circumference of the inner wall surface formed by the portion of the inner side of the shaft ax is smaller than the inner circumference of the inner wall surface formed by the apex of the convex portion (the portion closest to the central axis ax) is smaller than the inner wall surface of the second hole portion 51b ( The difference in the inner dimensions of the concavo-convex inner surface 53 corresponding to the region on the other opening side of the present invention. In other words, the depth of the sector shape of the inner wall surface of the first hole portion 51a is shallower than the depth of the sector shape of the inner wall surface of the second hole portion 51b. Further, with respect to the distance between the convex ring 53a and the concave ring 53b, the distance between the inner wall surfaces of the first hole portions 51a is also smaller than the distance between the inner wall surfaces of the second hole portions 51b.

On the other hand, the sub-hole 52 is formed from the lower surface of the relay substrate 33 to a position communicating with the main hole 51. The sub-hole 52 is a hole through which the bottom plate of the main hole 51 is formed in the thickness direction of the relay substrate 33. The inner wall surface 62 of the sub-hole 52 is inclined with respect to the surface (upper and lower surfaces) of the relay substrate 33, and the sectional area of the sub-hole 52 parallel to the surface of the relay substrate 33 is narrowed from the other opening side toward the main hole 51 side. . The method in which the main holes 51 and the sub holes 52 are formed separately is different. Details of this point will be described later.

An insulating film including a hafnium oxide film or the like (not shown) is formed on the inner wall surface of the substrate through-hole 48, and a conductor portion 50 containing a metal such as copper (Cu) is filled inside by the electric field plating or the like. Further, a diffusion preventing film or an adhesion film may be present between the insulating film and the conductor portion 50. One end of the conductor portion 50 (on the upper surface side of the relay substrate 33) is exposed at the upper end. The upper surface side wiring 38 is connected to the upper surface side. Further, the lower end of the opening portion of the conductor portion 50 on the other side (the upper surface side of the relay substrate 33) is electrically connected to the lower surface side wiring 47. Thereby, the drive IC 34 and the piezoelectric element 32 are electrically connected via the IC electrode 41, the upper surface side wiring 38, the through wiring 45, the bump electrode 40, and the lower surface side wiring 47. As shown in FIG. 6, in the present embodiment, the ratio (t2) of the thickness (t2) of the relay substrate 33 to the minimum inner dimension (D2) of the opening of the substrate through-hole 48 on the upper surface of the relay substrate 33 (t2/) D2), that is, the value of the aspect ratio is 10 or more. Specifically, for example, the thickness (t2) of the relay substrate 33 is 300 [μm] or more, and the minimum inner dimension (D2) of one of the substrate through holes 48 is 25 [μm] or less. With this configuration, since the through wiring 45 can be disposed at a higher density on the relay substrate 33, it is possible to increase the density of other wirings that are electrically connected to the through wiring 45, thereby contributing to downsizing of the relay substrate 33 and even the recording head. 3 miniaturization.

The relay substrate 33 and the pressure chamber forming substrate 29 (specifically, the pressure chamber forming substrate 29 in which the diaphragm 31 is laminated) are in a state in which the bump electrodes 40 are interposed as shown in FIGS. 2 and 3 . It is joined by the bonding resin 43 which has the characteristics of both thermosetting property and photosensitive property. In addition to the function as an adhesive for bonding the relay substrate 33 and the pressure chamber forming substrate 29, the bonding resin 43 also functions as a driving between the relay substrate 33 and the pressure chamber forming substrate 29 without hindering the piezoelectric element 32. The function of the spacer of the gap and the function of sealing the region as a region surrounding the region in which the piezoelectric element 32 is formed. Further, as the bonding resin 43, for example, thermosetting such as an epoxy resin, an acrylic resin, a phenol resin, a polyimide resin, a polyoxymethylene resin, a styrene resin or the like and containing a photopolymerization initiator or the like is preferably used. Resin.

The driver IC 34 disposed on the relay substrate 33 is an IC chip that performs control for selectively applying a driving signal to each piezoelectric element 32 based on the ejection data (grating material) from the control unit of the printer 1 and is different in isolation. An adhesive such as an anisotropic conductive film (ACF: Anisotropic Conductive Film) is laminated on the upper surface side of the relay substrate 33 on the side opposite to the piezoelectric element 32 side. A power supply wiring (not shown) is formed on the surface of the drive IC 34 on the side of the relay substrate 33. Electrode or IC electrode 41. The IC electrode 41 outputs a terminal for driving a signal of each piezoelectric element 32, and is electrically connected to the upper surface side wiring 38 of the relay substrate 33 as described above.

Further, the recording head 3 formed as described above introduces the ink from the ink cartridge 7 into the pressure chamber 30 through the liquid introduction path 18, the common liquid chamber 25, and the individual communication port 26. In this state, the piezoelectric element 32 is driven by selectively applying a driving signal to the piezoelectric element 32 via the respective wirings including the through wiring 45 formed on the relay substrate 33 from the driving IC 34, thereby generating pressure in the pressure chamber 30. change. By this pressure fluctuation, the recording head 3 ejects ink droplets from the nozzle 22 via the nozzle communication port 27.

Next, a step of forming the nozzle communication port 27 facing the communication substrate 24 will be described with reference to Figs. 7 to 17 . First, masks 56a and 56b are formed on the lower surface of the substrate 24' made of a material having a thickness of 400 [μm] which is the material of the interconnecting substrate 24 (mask forming step). The mask may be, for example, a ruthenium oxide film, a tantalum nitride film, or a resist containing a photosensitive resin, and the dry etching step or the wet etching step described below may function as a mask. After the masks 56a and 56b are formed, as shown in FIG. 7, the mask openings 55a and 55b are formed in the masks 56a and 56b, respectively, by exposure and development. One mask opening 55a is a main hole forming step and a mask opening portion of the anisotropic wet etching step, and the other mask opening 55b is a sub hole forming step and a mask opening portion of the anisotropic wet etching step. . Here, the minimum inner dimension of the mask opening 55a is set to 25 [μm] or less (the minimum inner dimension of the reserved hole 65 to be described later is 25 [μm] or less), and the mask opening 55b is set. It is 40 [μm] or less (the minimum inner dimension (D1) of the final shape of the nozzle communication port 27 is 40 [μm] or less). Next, the substrate 24' is placed in an etching apparatus (not shown), and a main hole forming step is performed from the side of the mask opening 55a. The main hole forming step of this embodiment is divided into an initial first step and a second step subsequent to the second step. The first step is a step of partially removing the substrate 24' from one surface (upper surface) of the substrate 24' to the thickness direction of the substrate, and the second step is from the bottom of the portion removed by the first step to the thickness of the substrate. The portion of the substrate 24' that is slightly closer to the upper surface than the other surface (lower surface) The step of ground removal. In other words, the first step is a step of forming a specific range of the opening side in the main hole 68, and the second step is a step of forming a specific range of the side on which the sub-hole 71 to be described later is formed in the main hole 68. In any step, an isotropic dry etching step by means of an inductive coupled plasma (ICP) method is repeatedly performed in sequence, and a portion of the substrate 24' is removed by etching to form a protective film. The protective film forming step and the Bosch method of removing the protective film removing step (anisotropic dry etching step) formed on the protective film on the bottom surface of the concave portion formed by the isotropic dry etching.

In the isotropic dry etching step, sulfur hexafluoride (SF ₆ ) is used as an etching gas and plasmad, and as shown in FIG. 8, the substrate 24' is isotropically etched by F radical or F ion. . In the isotropic etching, since the side etching progresses to the outside of the mask opening 55a in plan view, the first recess 57a of the first stage having a slightly larger area than the mask opening 55a is formed. The isotropic dry etching step has a plurality of etching conditions different in processing time per one time. In the etching conditions of the isotropic dry etching step of the first step, the processing time of each of the isotropic dry etching steps is set to be shorter than the case of the isotropic dry etching step of the second step. In other words, the processing time per one time of the etching conditions for the side on which the sub-hole 71 is formed in the main hole 68 is longer than the etching side of one opening side (one side of the substrate 24') on the side opposite to the side on which the sub-hole 71 is formed. Processing time per 1 time. Therefore, the depth (the dimension in the thickness direction of the substrate) of the first concave portion 57 formed in the first step is shallower than the depth of the second concave portion 67 to be described later. Moreover, the inner wall surface (side surface) of such a concave portion has an arc shape bent outward in cross section, and this portion is a concave ring 66b (corresponding to the concave portion of the present invention). Further, one or more steps may be further performed between the first step and the second step, and the processing time may be set to be longer in the order of execution of each step. That is, the processing time may be gradually increased as the processing of the main hole 68 progresses by the isotropic dry etching step.

When the first recess 57 of the first stage is formed, a protective film forming step is subsequently performed. In the protective film forming step, the gas is switched to C ₄ F ₈ , and as shown in FIG. 9, the inner wall surface (side wall and bottom surface) of the portion (first recess 57a) exposed by the dry etching step is exposed. A protective film 58 called a deposited film is formed. When the protective film 58 has been formed, the gas is again switched to SF ₆ , and as shown in FIG. 10, the protective film 58 formed on the bottom of the first recess 57a is removed. In the protective film removing step, a bias voltage is applied to the substrate 24', and ions introduced into the mask opening 55a are accelerated toward the bottom surface of the first recess 57a. Thereby, the protective film 58 of the bottom surface of the first recessed portion 57a is selectively removed in a state where the protective film 58 on the side surface of the first recessed portion 57a remains.

Similarly, as shown in FIG. 11, the isotropic dry etching step is performed to form the first recess 57b of the second stage below the first recess 57a of the first stage. As described above, since the inner wall surface (side surface) of the concave portion is curved outward in the cross-sectional view, a convex ring 66a is formed at a boundary portion between the concave portions 57a and 57b (corresponding to the convex portion of the present invention). ). In this manner, the isotropic dry etching step, the protective film forming step, and the protective film removing step are sequentially repeated, and as shown in FIG. 12, a specific range from the opening on the upper surface side to the thickness direction of the substrate is formed in plural. The first hole portion 69 in which the first concave portion 57 of the segment is connected in the thickness direction.

After the first hole portion 69 is formed, the second step is performed, and the isotropic dry etching step, the protective film forming step, and the protective film removing step are repeated in the same manner as in the first step, as shown in FIGS. 13 and 14 . As shown, a plurality of second recesses 67 are formed in the thickness direction of the substrate. Here, the processing time of each of the isotropic dry etching steps of the second step is set to be longer than that of the first step. Therefore, the depth of the second concave portion 67 formed in the second step is deeper than the depth of the first concave portion 57 of the first hole portion 69. Further, since the processing time of the isotropic dry etching step is long, and the side etching progresses to the outside of the inner wall surface of the first recess 57, the area of the second recess 67 which is perpendicular to the surface of the substrate 24' is larger than that of the second recess 67. 1 The area of the recess 57. Further, the depth of the concave ring 66b formed by the inner wall surface (side surface) of the second concave portion 67 is also deeper than the first concave portion 57. Further, the formation pitch of the second concave portion 67 is also larger than the formation pitch of the first concave portion 57. In this manner, the isotropic dry etching step, the protective film forming step, and the protective film removing step are sequentially repeated, as shown in FIG. 14, from the lower end of the first hole portion 69 to the lower surface of the substrate thickness direction. a second front portion 67 of the plurality of segments is formed slightly forward (at a position close to the upper surface) The second hole portion 70 is connected. In other words, the main hole 68 is formed in a state in which the bottom plate 64 (corresponding to the predetermined portion of the opening of the present invention) remains between the lower surface of the substrate 24' and does not penetrate the substrate 24'.

As shown in FIG. 14, the inner wall surface of the main hole 68 including the first hole portion 69 and the second hole portion 70 formed in this manner is formed in the thickness direction of the substrate 24' as in the above-described substrate through hole 48. There is a corrugated concave inner surface 66. In other words, the convex rings 66a projecting from the inner wall surface of the substrate through-hole 48 toward the central axis side and the adjacent convex rings 66a are alternately arranged in the thickness direction (along the imaginary central axis of the main hole 68). The concave ring 66b is formed to have a folded-like unevenness on the inner wall surface of the substrate through-hole 48. In other words, on the inner wall of the main hole 68, irregularities are periodically repeated along the central axis of the main hole 68 to form the concavo-convex inner surface 66.

Here, in the main hole forming step, when the protective film forming step is performed in a state in which the convex ring 66a is formed, the shadow of the convex ring 66a may be observed from the side of the mask opening 55a into which the C ₄ F ₈ gas is introduced. Part of the protective film is not sufficiently formed. Further, as the main hole forming step progresses, the insufficient formation of the protective film is damaged by dry etching. Therefore, the protective film is broken, and there is an abnormality that the opening of the hole is expanded more than the predetermined one, and the shape of the hole is distorted. In particular, the closer to the upper surface side of the main hole 68, the more the number of accumulations of the dry etching step before the formation of the main hole 68 is completed, so that it is likely to be more damaged and the above-mentioned abnormality is likely to occur. Further, in the case where the main hole 68 having a larger value and a deeper aspect ratio is processed, the cumulative number of times is increased accordingly, so that the above-mentioned abnormality is more likely to occur in the portion of the main hole 68 which is opened closer to the upper surface side. In this regard, in the etching conditions of the isotropic dry etching step in the first step, the processing time is set to be shorter than in the second step, and the difference in the inner dimensions of the concavo-convex inner surface 66 (the depth of the sector) Since the difference in size between the inner and outer surfaces 66 of the unevenness formed in the first step is smaller, the protective film can be uniformly formed on the inner wall surface on the upper surface side of the main hole 68. Thereby, even in the case where the main hole 68 is formed deeper (the aspect ratio is 10 or more), the above-described abnormality can be suppressed. On the other hand, in the etching conditions of the isotropic dry etching step in the second step, since the processing time is set to be longer than in the first step, the depth of the second recess 67 in the thickness direction of the substrate is formed to be larger. Since the depth of the first concave portion 57 in the first step is deeper, the isotropic dry etching step and the formation of the protective film before the main hole 68 reaches a certain depth can be reduced as compared with the case where the etching condition is set to be the same as in the first step. The number of repetitions of the steps and the protective film removal step. Thereby, when the main hole 68 having an aspect ratio of 10 or more is formed, the step time can be further shortened while maintaining the accuracy of the size and shape of the hole.

However, although the main hole 68 may be penetrated in the thickness direction of the substrate 24' by repeating the isotropic dry etching step, the protective film forming step, and the protective film removing step, the etching gas flows rapidly during the penetration. Since the through portion is open, the opening on the through side (the opening on the lower surface side of the substrate 24') is unintentionally enlarged and the shape of the opening is collapsed. In order to prevent such a problem, in the present embodiment, the main hole 68 is formed so as not to penetrate the substrate 24' and is formed slightly forward of the lower surface in the thickness direction of the substrate. The thickness of the bottom plate 64 from the bottom (lower end) of the main hole 68 to the lower surface of the substrate 24' is set to, for example, 10% or less of the thickness of the substrate 24'. Then, the opening portion 55b of the opening portion on the lower surface side of the reserved hole 65 is irradiated with the laser light by the mask opening portion 55b of the mask 56b on the lower surface side in the thickness direction of the substrate 24'. As shown in FIG. 15, the sub-hole 71 penetrating the bottom plate 64 of the main hole 68 is formed (the sub-hole forming step). Since the bottom plate 64 of the main hole 68 can be penetrated, the irradiation energy of the laser can be suppressed to be low. Further, the wavelength of the laser light may be a range suitable for processing of the germanium substrate. Thus, the sub-hole 71 is formed by the laser processing through the bottom plate 64 of the main hole 68, whereby the main hole 68 and the sub-hole 71 form the reserved hole 65 which becomes the nozzle communication port 27. Thereby, the other opening of the reserved hole 65 (the opening on the lower surface side of the substrate) is prevented from being enlarged more than predetermined and its shape is collapsed. Further, since the processing time of the laser light is shorter than that of the above-described processing using the Bosch method, the time of the entire step can be shortened. Further, since the irradiation time of the laser light is short, it is possible to prevent the peripheral edge of the opening of the sub-hole 71 from becoming brittle due to the heat of the laser light.

If the reserved hole 65 has been formed in the substrate 24', then the anisotropic wet etching step is performed by exposing the reserved hole 65 to the etching solution containing KOH by using the masks 56a, 56b. By this step, the unevenness or the like of the inner wall surface of the reserved hole 65 is removed, and finally, as shown in Fig. 16, the nozzle communication port 27 having the crystal surface of the ruthenium substrate as the inner wall is formed. The substrate 24' of the present embodiment includes a tantalum substrate having a crystal plane orientation of the upper and lower surfaces of (110) plane, and the etching rate of the (110) plane of the etching solution containing potassium hydroxide is higher than the etching rate of the other crystal planes. The inner wall surface of the nozzle communication port 27 formed thereby is constituted by, for example, a (111) plane that intersects with the (110) plane. In the anisotropic wet etching step, processing of other flow paths, such as the common liquid chamber 25 or the individual communication ports 26, is also performed simultaneously. Thus, since the shape of the final nozzle communication port 27 is formed by the anisotropic wet etching step by the formation of the reserved hole 65 by the Bosch method and the laser processing, the aspect ratio can be obtained with good dimensional and shape accuracy. The value is a nozzle communication port 27 of 10 or more. In particular, since there is no uneven portion which is caused by flow disturbance or bubble retention when the ink flows through the nozzle communication port 27, the nozzle communication port 27 functions as one of the flow paths through which the fluid is supplied. In the case of a through hole, the manufacturing method of this embodiment is suitable. Further, as shown in FIG. 17, after the masks 56a and 56b are removed, the inner wall of the flow path such as the surface of the substrate and the nozzle communication port 27 is formed, for example, of tantalum oxide (Ta ₂ O ₅ ) or cerium oxide (SiO _{2 ).} The material is resistant to the ink film 72, and the communication substrate 24 is obtained. Alternatively, the anisotropic wet etching step may be omitted, and the reserved hole 65 may be used as the nozzle communication port 27.

As described above, the step of forming the nozzle communication port 27 with respect to the communication substrate 24 is described. However, the substrate through-hole 48 of the relay substrate 33 of the present embodiment is also formed through the same steps as when the nozzle communication port 27 is formed. That is, by repeating the main hole forming step of the isotropic dry etching step, the protective film forming step, and the protective film removing step (anisotropic dry etching step), the lower surface of the interposer substrate 33 is repeatedly performed. The main hole 51 is formed in a state in which the bottom plate remains, and the sub hole 52 is formed by the sub hole forming step of the bottom plate (opening portion for opening) of the main hole 51 by laser processing, and the substrate through hole 48 is formed in the relay substrate 33. In the main hole forming step, as in the case of the nozzle communication port 27, it is divided into two steps of the initial first step and the subsequent second step, and in the etching condition of the isotropic dry etching step of the first step, The processing time for each of the steps is set to be shorter than the processing time of each of the etching conditions of the isotropic dry etching step of the second step. Thereby, about being formed in the main hole 51 The unevenness inner surface 53 of the wall surface has a difference in the inner dimension of the inner surface 53 of the inner wall surface of the first hole portion 51a which is smaller than the inner dimension of the inner surface 53 of the inner wall surface of the second hole portion 51b. Further, similarly to the case of the nozzle communication port 27, after the main hole 51 and the sub-hole 52 are formed, the uneven inner surface 53 of the inner wall of the substrate through-hole 48 is removed by performing the anisotropic wet etching step. However, in the present embodiment, the anisotropic wet etching step is omitted. Thereby, the inner wall of the substrate through-hole 48 is in a state in which the uneven inner surface 53 or the unevenness between the main hole 51 and the sub-hole 52 is left. As a result, the uneven shape is a retaining member for the conductor portion 50 (filling material) filled in the substrate through-hole 48, and the conductor portion 50 is prevented from falling off from the substrate through-hole 48.

Thus, the thickness (t) of a substrate can be formed on the substrate (ie, t1 of the connected substrate 24 or t2 of the relay substrate 33) with respect to an opening having a minimum inner dimension (D) {ie, the nozzle communication port 27 D1, or a value (t/D) of the substrate through-hole 48 (t/D) (value of the aspect ratio) is 10 or more through holes (nozzle communication port 27, substrate through hole 48), and may be at a specific thickness ( a substrate having a diameter of 300 [μm] or more, which forms a through hole having a smaller inner dimension of the opening at a higher density and higher precision, thereby contributing to miniaturization of the electronic device 14, and even contributing to the recording head 2 and The miniaturization of the printer 1.

In the above, the nozzle communication port 27 is exemplified as a through hole through which a fluid flows. However, the present invention is not limited thereto, and is a through hole that constitutes at least a part of a flow path through which a fluid flows, and forms an aspect ratio on the ruthenium substrate. The present invention can be applied to a configuration of through holes of 10 or more. In addition, the through wiring is not limited to the through wiring 45, and is a member that turns on the first electronic component disposed on one surface side of the substrate and the second electronic component disposed on the other surface side of the substrate. The invention can be applied. For example, a substrate such as a TCP (Tape Carrier Package) on which a driver IC is mounted may be connected to the upper surface of the relay substrate.

Further, in the above, the present invention can be applied as long as it is an electronic device in which a plurality of layers of substrates are bonded by an adhesive and has a through hole or a through wiring for supplying a fluid to a substrate. For example, detecting pressure changes, vibrations, displacements, etc. in the movable area The present invention can also be applied to a sensor or the like.

The fluid is not limited to a liquid such as an ink, and may be a gas or the like.

Further, in the above-described embodiment, the ink jet recording head 3 is described as an example of the liquid ejecting head. However, the present invention can also be applied to an electronic device in which a plurality of layers are bonded by an adhesive. And a liquid ejecting head having a through hole for circulating a fluid or an electronic device penetrating the wiring on one substrate. For example, the present invention can also be applied to a color material ejection head used for manufacturing a color filter such as a liquid crystal display, or an electrode material for electrode formation of an organic EL (Electro Luminescence) display, an FED (Face Light Emitting Display), or the like. A discharge head, a biological organic matter ejection head for manufacturing a biochip (biochemical element), and the like. A solution of each of R (red), G (green), and B (blue) as a liquid is ejected from the color material ejection head for the display manufacturing apparatus. In addition, a liquid electrode material which is a liquid is ejected from the electrode material discharge head for the electrode forming apparatus, and a solution of a biological organic substance which is a liquid is ejected from the bioorganic material ejection head for the wafer manufacturing apparatus.

33‧‧‧Relay substrate

38‧‧‧Upper surface wiring

45‧‧‧through wiring

47‧‧‧ Lower surface side wiring

48‧‧‧Substrate through hole

50‧‧‧Conductor

51‧‧‧ main hole

51a‧‧‧1st hole

51b‧‧‧2nd hole

52‧‧‧Sub-hole

53‧‧‧ inside the bump

53a‧‧‧ convex ring

53b‧‧‧ concave ring

62‧‧‧ inner wall of the secondary hole

Ax‧‧‧ central axis

D2‧‧‧Minimum inner size

T2‧‧‧ thickness

Claims (15)

An electronic device in which a plurality of layers are laminated, and at least one of the plurality of substrates is a substrate having a thickness of 300 [μm] or more; and the substrate is formed through the substrate The through hole in the thickness direction; the ratio (t/D) of the thickness (t) of the substrate to the minimum inner dimension (D) of the opening of one of the through holes is 10 or more. The electronic device according to claim 1, wherein the inner wall surface of the through hole is periodically formed with irregularities along a central axis of the through hole, and the inner wall surface formed by the bottom of the concave portion of the inner wall surface of the through hole The difference between the inner circumference of the inner wall surface formed by the inner circumference and the apex of the convex portion of the uneven portion is larger in the region on the other opening side than in the region on the other opening side. The electronic device of claim 2, wherein the minimum inner dimension of the through hole is 25 [μm] or less. The electronic device of any one of claims 1 to 3, wherein the through hole comprises a main hole including the opening and a sub hole including another opening; and an inner wall surface of the sub hole is opposite to a surface of the substrate The cross-sectional area of the surface of the sub-hole orthogonal to the thickness direction of the substrate gradually decreases from the other opening side toward the main hole side. The electronic device of claim 1, wherein the opening of the through hole has a polygonal shape, and a length of the smallest side of the polygon is 40 [μm] or less. The electronic device of claim 5, wherein the inner wall surface of the through hole comprises a crystal face of the base plate including the side of the polygon. The electronic device of any one of claims 1 to 6, wherein the through hole is internal The through wiring of the conductor is disposed, and the through wiring is electrically connected to the first electronic component disposed on one surface side of the one substrate and the second electronic component disposed on the other surface side of the one substrate. The electronic device according to any one of claims 1 to 6, wherein the through hole constitutes at least a part of a flow path through which a fluid flows. A liquid ejecting head comprising the electronic device of claim 7, characterized by comprising: an actuator substrate as the first electronic component, configured to cause a pressure fluctuation of a liquid in the pressure chamber to be generated from the pressure An actuator that ejects a liquid from a nozzle of the chamber; and a drive circuit that is the second electronic component is driven by the actuator; and the substrate is disposed between the actuator substrate and the drive circuit; The through wiring causes the actuator to be electrically connected to the drive circuit. A liquid ejection head comprising the electronic device of claim 8, characterized by comprising: a nozzle forming substrate formed with a nozzle for ejecting a liquid; and a pressure chamber forming substrate formed with a pressure chamber communicating with the nozzle; And an actuator that causes a pressure fluctuation in the liquid in the pressure chamber; and the substrate is disposed between the nozzle forming substrate and the pressure chamber forming substrate; and the one substrate is formed to connect the nozzle to the pressure chamber The above through hole. A liquid ejecting apparatus comprising the liquid ejecting head as claimed in claim 9 or 10. A method of manufacturing an electronic device, which is coupled to at least one substrate of a plurality of substrates, A method of manufacturing an electronic device that penetrates a through-hole in a thickness direction of the substrate, and is characterized in that the through-hole is formed by a mask forming step of forming a mask on a surface of the substrate; the main hole is formed a step of sequentially performing a dry etching step of removing a portion of the substrate from one surface side of the substrate via the mask, and a protective film forming a protective film on the exposed portion of the substrate formed by dry etching a forming step of forming a main hole that does not penetrate the thickness direction of the substrate; and a laser processing step of irradiating a predetermined portion of the opening of the other surface of the one of the through holes to form an opening A secondary hole in the main hole. The method of manufacturing the electronic device of claim 12, wherein the dry etching step comprises an isotropic dry etching step; and the isotropic dry etching step has a plurality of etching conditions different in processing time per one time; The processing time per one time of the etching conditions on the side of the sub-hole is longer than the processing time per one time of the etching conditions on the one side of the one substrate. The method of manufacturing an electronic device according to claim 12 or 13, wherein in the mask forming step, a minimum inner dimension of the opening of the mask which is formed to form the through hole is 25 [μm] or less. The manufacturing method of the electronic device of claim 12 or 13, further comprising: an anisotropic etching step of exposing the through hole to an anisotropic etching liquid having a different etching speed to a crystal face of the germanium substrate, and The inner wall of the through hole is anisotropically etched.