JP4835828B2 - Method for manufacturing liquid jet head - Google Patents

Description

  The present invention relates to a method for manufacturing a liquid ejecting head that ejects liquid, and more particularly, to a method for manufacturing an ink jet recording head that ejects ink as a liquid.

  As an ink jet recording head that is a liquid ejecting head, for example, a flow in which a pressure generating chamber communicating with a nozzle opening and a communicating portion communicating with the pressure generating chamber are formed and a piezoelectric element is provided on one surface side thereof. Some include a path forming substrate and a reservoir forming substrate (sealing substrate) in which a reservoir portion that constitutes a part of the reservoir together with a communication portion of the flow path forming substrate is formed. As the reservoir forming substrate, for example, a silicon single crystal substrate having a plane orientation (110) is used, and the reservoir portion is formed by anisotropically etching the reservoir forming substrate via a mask pattern or the like. (For example, see Patent Document 1).

  The reservoir section (ink reservoir) is formed to communicate with a plurality of pressure generation chambers (pressure chambers) arranged side by side, and the pressure generation chamber located at the center of the row and the pressure located at the end In order to make the ejection characteristics of the ink droplets uniform between the generation chambers, there is one in which a gradually decreasing portion having a gradually decreasing width is provided at both longitudinal end portions of the reservoir portion (see, for example, Patent Document 2).

  When the reservoir portion having such a gradual portion is formed only by anisotropic etching as described above, a region where the reservoir formation substrate (silicon single crystal substrate) faces the reservoir portion is formed at the tip portion of the gradual portion. There is a problem in that the ink flows out and remains in a bowl shape, thereby causing a difference in flow path resistance of each pressure generating chamber and causing variation in ink ejection characteristics.

  Such a problem exists not only in the manufacturing method of an ink jet recording head that discharges ink, but also in the manufacturing method of other liquid ejecting heads that discharge a liquid other than ink.

International Publication No. 2004/007206 (FIG. 12, pages 24-25, etc.) Japanese Patent Laid-Open No. 2003-63010 (FIG. 2 etc.)

  In view of such circumstances, it is an object of the present invention to provide a method of manufacturing a liquid ejecting head that can satisfactorily form a reservoir portion having a predetermined shape on a reservoir forming substrate.

A first aspect of the present invention that solves the above-described problem is a pressure in which a plurality of pressure generation chambers communicating with the nozzle openings are arranged side by side and a pressure is applied on one surface side to eject droplets into the pressure generation chamber. A flow path forming substrate provided with a generating means, and a reservoir portion having a gradually decreasing portion that is communicated with a plurality of the pressure generating chambers and gradually decreases in width toward the outside at both ends in the juxtaposed direction of the pressure generating chambers The reservoir portion is formed by anisotropically etching the reservoir forming substrate made of a silicon single crystal substrate having a surface orientation (110) through a mask pattern having a predetermined shape. And the wall surface along the longitudinal direction of the pressure generating chamber of the reservoir portion is constituted by the first (111) surface perpendicular to the (110) surface, and the other wall surface is the first (111) surface. And 70.5 A method of manufacturing a liquid jet head including a surface including a second (111) surface having an angle of °, and when forming the reservoir portion, before or during the etching of the reservoir forming substrate, A corner portion of the first (111) surface, which is a wall surface along the longitudinal direction of the pressure generating chamber, of the reservoir portion and the second (111) surface constituting the wall surface on the pressure generating chamber side is an obtuse angle. In the method of manufacturing a liquid jet head, at least one through-hole penetrating the reservoir forming substrate in the thickness direction is formed by laser processing at a tip portion of the gradually decreasing portion.
In the first aspect, it is possible to satisfactorily form the reservoir portion penetrating the reservoir forming substrate with a predetermined opening shape. That is, no etching residue is generated in the region serving as the reservoir. Accordingly, the flow resistance of the pressure generating chambers arranged in parallel is constant, the ink ejection characteristics are uniformized, and the printing quality is greatly improved.

According to a second aspect of the present invention, the mask pattern has a correction pattern that forms a plurality of openings in a region facing the reservoir, and the formation of the reservoir via the openings In the method of manufacturing a liquid jet head according to the first aspect, the reservoir forming substrate is anisotropically etched.
In the second aspect, the etching rate of the reservoir forming substrate is substantially increased, and the reservoir portion having a predetermined shape can be formed in a relatively short time.

In a third aspect of the present invention, the length of the second (111) surface constituting the wall surface on the pressure generating chamber side that forms the one corner of the reservoir is 200 μm or less. The method of manufacturing the liquid jet head according to the first or second aspect is characterized by the above.
In the third aspect, since the through hole is easily formed by laser processing, the reservoir portion can be formed more satisfactorily.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
1 is an exploded perspective view showing an ink jet recording head manufactured by a manufacturing method according to Embodiment 1 of the present invention, and FIG. 2 is a plan view and a cross-sectional view of FIG. As shown in the figure, the flow path forming substrate 10 is formed of a silicon single crystal substrate having a plane orientation (110) in this embodiment, and one surface thereof is previously formed of silicon dioxide by thermal oxidation to a thickness of 0.5 to 2 μm. The elastic film 50 is formed.

  A plurality of pressure generating chambers 12 are arranged in parallel in the width direction of the flow path forming substrate 10. Further, a communication portion 13 is formed in a region outside the longitudinal direction of the pressure generation chamber 12 of the flow path forming substrate 10, and the communication portion 13 and each pressure generation chamber 12 are provided for each pressure generation chamber 12. Communication is made via a path 14. The communication portion 13 constitutes a part of a reservoir 100 that communicates with a reservoir portion 31 of a reservoir forming substrate 30 described later and serves as a common ink chamber for the pressure generation chambers 12. The ink supply path 14 is formed with a narrower width than the pressure generation chamber 12, and maintains a constant flow path resistance of ink flowing into the pressure generation chamber 12 from the communication portion 13.

On the opening surface side of the flow path forming substrate 10, a nozzle plate 20 having a nozzle opening 21 communicating with the vicinity of the end of each pressure generating chamber 12 on the side opposite to the ink supply path 14 is provided with an adhesive or heat. It is fixed by a welding film or the like. The nozzle plate 20 has a thickness of, for example, 0.01 to 1 mm, a linear expansion coefficient of 300 ° C. or less, for example, 2.5 to 4.5 [× 10 ⁻⁶ / ° C.], glass ceramics, silicon It consists of a single crystal substrate or stainless steel.

  On the other hand, as described above, the elastic film 50 having a thickness of, for example, about 1.0 μm is formed on the surface of the flow path forming substrate 10 opposite to the nozzle plate 20, and the elastic film 50 is formed on the elastic film 50. The insulator film 51 having a thickness of, for example, about 0.4 μm is formed. Further, on the insulator film 51, a lower electrode film 60 having a thickness of, for example, about 0.2 μm, a piezoelectric layer 70 having a thickness of, for example, about 1.0 μm, and a thickness of, for example, about 0 The upper electrode film 80 having a thickness of 0.05 μm is laminated by a process described later to constitute the piezoelectric element 300. Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80. In general, one electrode of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure generating chamber 12. In the present embodiment, the lower electrode film 60 is used as a common electrode of the piezoelectric element 300 and the upper electrode film 80 is used as an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for convenience of a drive circuit and wiring.

  In addition, a lead electrode 90 made of a metal material such as gold (Au) is connected to the upper electrode film 80 of each piezoelectric element 300, and the piezoelectric element 300 is selected via the lead electrode 90. Thus, a voltage is applied.

  Furthermore, the surface on the piezoelectric element 300 side of the flow path forming substrate 10 is made of, for example, a silicon single crystal substrate having a plane orientation (110), and has a reservoir portion 31 that constitutes at least a part of the reservoir 100. Are bonded via an adhesive layer made of an adhesive or the like. The reservoir portion 31 is formed along the direction in which the pressure generating chambers are arranged side by side, and a gradually decreasing portion 32 whose width gradually decreases toward the outside is provided at both ends in the longitudinal direction. Thereby, the opening of the reservoir | reserver part which concerns on this embodiment becomes substantially trapezoid shape. The reservoir unit 31 communicates with the communication unit 13 through the elastic film 50 and the through-hole 52 provided in the insulator film 51, and the reservoir 100 is formed by the reservoir unit 31 and the communication unit 13.

  The gradually decreasing portion 32 of the reservoir portion 31 is provided in order to make the flow path resistance of each pressure generating chamber constant, and to make the discharge characteristics of the ink droplets discharged from the nozzle openings uniform.

  The reservoir forming substrate 30 having such a reservoir portion 31 is made of a silicon single crystal substrate having a plane orientation (110) that is the same material as the flow path forming substrate 10, and the reservoir portion 31 will be described later in detail. The substrate 30 is formed by anisotropic etching from both sides. As a result, as shown in FIG. 3, the wall surface 33 along the longitudinal direction of the pressure generating chamber of the reservoir portion 31 is configured by the first (111) surface perpendicular to the (110) surface, and the other wall surfaces are the first wall surface. The first (111) surface (wall surface 33) is a surface including a second (111) surface 34 that forms an angle of 70.53 °. Therefore, on one side of the gradually decreasing portion 32, the angle θ of the corner between the wall surface 33 and the second (111) surface 34 constituting the wall surface on the pressure generating chamber 12 side is an obtuse angle. Although not shown, it has an acute angle.

  Note that a piezoelectric element holding portion 35 is provided in a region facing the piezoelectric element 300 of the reservoir forming substrate 30. Since the piezoelectric element 300 is formed in the piezoelectric element holding portion 35, it is protected in a state where it is hardly affected by the external environment. In addition, the piezoelectric element holding part 35 may be sealed or may not be sealed. A drive IC 210 for driving the piezoelectric element 300 is mounted on the reservoir forming substrate 30. Then, the leading end portion of each lead electrode 90 drawn from each piezoelectric element 300 to the outside of the piezoelectric element holding portion 35 and the driving IC 210 are electrically connected via the driving wiring 220.

  Furthermore, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded onto a region corresponding to the reservoir portion 31 of the reservoir forming substrate 30. The sealing film 41 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μm). The sealing film 41 seals one surface of the reservoir unit 31. Yes. The fixing plate 42 is made of a hard material such as metal (for example, stainless steel (SUS) having a thickness of 30 μm). Since the region of the fixing plate 42 facing the reservoir 100 is an opening 43 that is completely removed in the thickness direction, one surface of the reservoir 100 is sealed only with a flexible sealing film 41. Has been. In addition, an ink introduction port 44 for supplying ink from the ink cartridge into the reservoir 100 is provided in a region facing the reservoir portion 31 of the compliance substrate 40.

  In such an ink jet recording head of this embodiment, ink is taken into the reservoir 100 from an external ink supply means (not shown) via the ink introduction port 44, and the interior is filled with ink from the reservoir 100 to the nozzle opening 21. After that, according to the recording signal from the drive IC 210, a voltage is applied between each of the lower electrode film 60 and the upper electrode film 80 corresponding to the pressure generating chamber 12 to bend and deform the piezoelectric element 300 and the diaphragm. The pressure in each pressure generating chamber 12 increases and ink is ejected from the nozzle opening 21.

  Hereinafter, a method for manufacturing such an ink jet recording head, specifically, a method for forming a reservoir forming substrate constituting the ink jet recording head will be described with reference to FIGS. 4 is a cross-sectional view of the reservoir forming substrate in the longitudinal direction of the pressure generating chamber. FIG. 4B corresponds to the BB ′ cross section of FIG. 5A, and FIG. This corresponds to the CC ′ cross section of 5 (b).

  First, as shown in FIG. 4A, a reservoir forming substrate 30 which is a silicon single crystal substrate having a plane orientation (110) is thermally oxidized in a diffusion furnace at about 1100 ° C. to form a reservoir portion 31 and the like on the surface. A silicon dioxide film 130 serving as a mask is formed. Although the thickness of the reservoir forming substrate 30 is not particularly limited, in this embodiment, a silicon single crystal substrate (silicon wafer) having a thickness of about 400 μm is used as the reservoir forming substrate 30.

  Next, as shown in FIGS. 4B and 5A, when the silicon dioxide film 130 is patterned by etching through a resist film or the like, the reservoir 31 is formed by etching. A mask pattern 140 to be a mask is formed. Here, a correction pattern 141 having a plurality of openings 142 is provided in a region of the mask pattern 140 facing the reservoir portion 31. In FIG. 5A, only three openings 142 are shown, but a plurality of such openings 142 are arranged in all the areas where the reservoir 31 is formed (hatched areas). Yes.

  The shape of the correction pattern 141, that is, the shape and arrangement of each opening 142 is not particularly limited, and may be determined as appropriate according to the shape of the reservoir 31, but the end surface of each opening 142 has the first (111). ) Surface or the second (111) surface. Therefore, as described above, in one gradually decreasing portion 32 of the reservoir portion 31, the angle θ of the corner portion between the wall surface 33 and the second (111) surface 34a constituting the wall surface on the pressure generating chamber 12 side is an obtuse angle. (See FIG. 3). The reservoir portion 31 is preferably formed such that the length of the second (111) surface 34a intersecting the wall surface 33 is 200 μm or less. For this reason, in this embodiment, the length L of the portion corresponding to the second (111) surface 34a of the correction pattern 141 is formed to be 200 μm or less (FIG. 5A). In this embodiment, since the piezoelectric element holding portion 35 is simultaneously formed by etching together with the reservoir portion 31, the mask pattern 140 (silicon dioxide film 130) on the bonding surface side of the reservoir forming substrate 30 with the flow path forming substrate 10 is used. An opening 143 is formed in a region facing the piezoelectric element holding portion 35.

  Next, in the present invention, the first (111) surface (wall surface 33) along the longitudinal direction of the pressure generation chamber 12 of the reservoir section 31 and the second (111) constituting the wall surface on the pressure generation chamber 12 side. As shown in FIGS. 4 (c) and 5 (b), the reservoir forming substrate 30 is formed in the thickness direction by laser processing at a position corresponding to the tip of the gradually decreasing portion 32 where the corner with the surface 34a becomes an obtuse angle. At least one through hole 145 is formed. For example, in this embodiment, three through holes 145 having a diameter of about 30 μm are formed at the tip of the gradually decreasing portion 32.

  Next, as shown in FIG. 4D, the reservoir forming substrate 30 is anisotropically etched from both sides thereof through the mask pattern 140 having the predetermined shape described above. Thereby, the reservoir forming substrate 30 is favorably formed with the reservoir portion 31 penetrating the reservoir forming substrate 30 with a predetermined opening shape, and at the same time, the piezoelectric element holding portion 35 is formed.

  Here, the anisotropic etching of the silicon single crystal substrate proceeds in the depth direction while the (111) plane forming an angle of about 35 ° with the (110) plane is exposed. Further, as described above, each opening 142 of the correction pattern 141 needs to be formed along the first (111) surface or the second (111) surface of the reservoir forming substrate 30, so At the tip of the small part, each of these openings 142 must be formed relatively small. For this reason, when the reservoir portion is formed only by anisotropic etching as in the prior art, the reservoir forming substrate (silicon single crystal substrate) has a bowl-like shape in the region corresponding to the tip portion of the one gradually decreasing portion described above. There was a risk of being left behind.

  However, as in the present invention, by forming the through-hole 145 by laser processing, the reservoir forming substrate 30 is reliably etched through the through-hole 145, so that no saddle-like etching residue occurs. The reservoir portion 31 having a predetermined shape is formed satisfactorily. In addition, since the length of the opening 142 can be made relatively long at the tip of the other gradually decreasing portion 32, there is very little possibility that a bowl-like etching residue will occur even if the through hole 145 is not formed. .

  In addition, since the reservoir portion 31 having a predetermined shape is formed well in this way, the flow path resistance of the pressure generating chambers 12 arranged in parallel is made constant, and the ink droplet ejection characteristics are made uniform. Thus, the print quality can be greatly improved.

  Note that a plurality of reservoir forming substrates 30 having such a reservoir portion 31 and the like are actually integrally formed on a silicon wafer. That is, after a plurality of reservoir portions 31 and the like are formed on the silicon wafer by the process as described above, the silicon wafer is finally divided to form the reservoir forming substrate 30.

(Other embodiments)
Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, the through hole 145 is formed before the reservoir forming substrate 30 is etched. However, the present invention is not limited to this, and the reservoir forming substrate 30 is etched through the mask pattern 140 to form the reservoir. After forming the portion 31 to a certain depth, the reservoir portion 31 may be formed by forming a through hole by laser processing and then further etching the reservoir forming substrate 30. Even in this case, of course, the reservoir portion 31 having a predetermined shape can be formed satisfactorily and efficiently.

  In the above-described embodiment, the piezoelectric element made of a thin film is exemplified as the pressure generating unit for ejecting the ink droplets. However, the pressure generating unit is not particularly limited, and may be, for example, a heating element. .

  In the above-described embodiment, an ink jet recording head has been described as an example of a liquid ejecting head. However, the present invention is widely intended for all liquid ejecting heads and ejects liquids other than ink. Of course, the present invention can also be applied to a method of manufacturing a liquid jet head. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (surface emitting displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.

FIG. 3 is an exploded perspective view of the recording head according to the first embodiment. 2A and 2B are a plan view and a cross-sectional view of the recording head according to the first embodiment. 3 is a plan view showing a shape of a reservoir section according to Embodiment 1. FIG. FIG. 6 is a cross-sectional view illustrating a manufacturing process of the reservoir forming substrate according to the first embodiment. 6 is a plan view illustrating a manufacturing process of the reservoir forming substrate according to Embodiment 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Flow path formation board | substrate, 12 Pressure generation chamber, 20 Nozzle plate, 21 Nozzle opening, 30 Reservoir formation board | substrate, 31 Reservoir part, 32 Decrease part, 35 Piezoelectric element holding | maintenance part, 40 Compliance board | substrate, 50 Elastic film, 51 Insulator Film, 60 lower electrode film, 70 piezoelectric layer, 80 upper electrode film, 90 lead electrode, 100 reservoir, 210 drive IC, 220 drive wiring, 300 piezoelectric element

Claims (3)

A plurality of pressure generating chambers communicating with the nozzle openings, and a flow path forming substrate provided with pressure generating means for applying a pressure for ejecting droplets into the pressure generating chamber on one side; A reservoir forming substrate having a reservoir portion communicating with the pressure generation chamber and having a gradually decreasing portion whose width gradually decreases toward the outside at both ends in the juxtaposed direction of the pressure generation chambers;
The reservoir portion is formed by anisotropically etching the reservoir forming substrate made of a silicon single crystal substrate having a plane orientation (110) through a mask pattern having a predetermined shape, and the longitudinal direction of the pressure generating chamber of the reservoir portion. The wall surface along the direction is composed of the first (111) plane perpendicular to the (110) plane, and the other wall surface is a second angle forming an angle of 70.53 ° with the first (111) plane. A method of manufacturing a liquid jet head including a surface including a (111) surface,
When forming the reservoir portion, before or during the etching of the reservoir forming substrate, the first (111) surface which is a wall surface along the longitudinal direction of the pressure generating chamber of the reservoir portion and the pressure generation At least one that penetrates the reservoir forming substrate in the thickness direction by laser processing at the tip of one of the gradually decreasing portions where the corner with the second (111) surface constituting the wall surface on the chamber side becomes an obtuse angle. A method of manufacturing a liquid jet head, wherein two through holes are formed. The mask pattern has a correction pattern for forming a plurality of openings in a region facing the reservoir, and the reservoir forming substrate is anisotropically etched through the openings when the reservoir is formed. The method of manufacturing a liquid jet head according to claim 1, wherein: The length of the second (111) surface constituting the wall surface on the pressure generating chamber side forming the one corner of the reservoir portion is set to 200 μm or less. 3. A method for manufacturing a liquid jet head according to 2.

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