JP2004066538A - Liquid jet head, inspection method and manufacturing method thereof - Google Patents

Abstract

A liquid ejecting head capable of improving a yield and reducing a manufacturing cost, a method for inspecting the liquid ejecting head, and a method for manufacturing the same.
A sealing substrate (30) having a sealing portion (31) joined to a surface of a flow path forming substrate (10) facing the piezoelectric element (300) and sealing the piezoelectric element (300) is provided. A connection wiring 130 provided on the surface opposite to the bonding surface with the insulating film 35 for applying a voltage to the piezoelectric element 300, and the sealing substrate 30 is made of a silicon single crystal substrate. At least one exposed portion 34 from which the insulating film 35 is removed to expose the sealing substrate 30 is provided on the surface.
[Selection] Fig. 2

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid ejecting head for ejecting a liquid to be ejected, a method for inspecting the same, and a method for manufacturing the same. The present invention relates to an ink jet recording head for discharging ink droplets from nozzle openings, a method for inspecting the same, and a method for manufacturing the same.
[0002]
[Prior art]
A part of the pressure generating chamber communicating with the nozzle opening for discharging the ink droplet is constituted by a vibrating plate, and the vibrating plate is deformed by a piezoelectric element to pressurize the ink in the pressure generating chamber to discharge the ink droplet from the nozzle opening. Two types of ink jet recording heads have been put into practical use, one using a vertical vibration mode piezoelectric actuator that expands and contracts in the axial direction of a piezoelectric element, and the other using a flexural vibration mode piezoelectric actuator.
[0003]
In the former, the volume of the pressure generating chamber can be changed by bringing the end face of the piezoelectric element into contact with the vibration plate, and a head suitable for high-density printing can be manufactured. There is a problem in that a difficult process of cutting the piezoelectric element into a comb shape in accordance with the pitch and an operation of positioning and fixing the cut piezoelectric element in the pressure generating chamber are required, and the manufacturing process is complicated.
[0004]
On the other hand, in the latter, a piezoelectric element can be formed on a diaphragm by a relatively simple process of sticking a green sheet of a piezoelectric material in accordance with the shape of the pressure generating chamber and firing the green sheet. However, there is a problem that a certain amount of area is required due to the use of, and that high-density arrangement is difficult.
[0005]
On the other hand, in order to solve the latter disadvantage of the recording head, a uniform piezoelectric material layer is formed by a film forming technique over the entire surface of the diaphragm as disclosed in Japanese Patent Application Laid-Open No. 5-286131. A proposal has been made in which a material layer is cut into a shape corresponding to a pressure generating chamber by a lithography method and a piezoelectric element is formed so as to be independent for each pressure generating chamber.
[0006]
According to this, the work of attaching the piezoelectric element to the diaphragm is not required, and not only can the piezoelectric element be formed at a high density by a precise and simple method called lithography, but also the thickness of the piezoelectric element can be reduced. There is an advantage that it can be made thin and can be driven at high speed.
[0007]
Further, generally, a sealing substrate having a sealing portion for sealing the piezoelectric element is joined to a surface of the flow path forming substrate on which the pressure generating chamber is formed on the piezoelectric element side. Destruction due to the external environment of the piezoelectric element is prevented. The sealing substrate is formed of the same material as the flow path forming substrate on which the pressure generating chamber is formed, for example, a silicon single crystal substrate. A connection wiring is provided on the sealing substrate via an insulating film made of an oxide film, and a piezoelectric element and a driving IC for driving the piezoelectric element are connected via the connection wiring. ing.
[0008]
[Problems to be solved by the invention]
However, since the insulating film provided on the surface of the sealing substrate is generally formed by thermally oxidizing the sealing substrate made of a silicon single crystal substrate, a pinhole may be formed in the insulating film. is there. That is, when the sealing substrate is thermally oxidized in a state where foreign matter such as dust adheres to the sealing substrate, the foreign matter forms a pinhole in the insulating film. When the connection wiring is formed in the portion of the insulating film where the pinhole is formed, the silicon single crystal substrate serving as the sealing substrate and the connection wiring are electrically connected via the pinhole, There is a problem that an electrical malfunction such as a malfunction of the piezoelectric element occurs.
[0009]
Since such an electrical defect is found at the time of operation confirmation after product completion, it causes a reduction in yield and an increase in manufacturing cost.
[0010]
Such a problem exists not only in the ink jet recording head that discharges ink but also in other methods of manufacturing a liquid jet head that discharges liquid other than ink.
[0011]
In view of such circumstances, it is an object of the present invention to provide a liquid ejecting head capable of improving a yield and reducing a manufacturing cost, a method of inspecting the liquid ejecting head, and a method of manufacturing the same.
[0012]
[Means for Solving the Problems]
According to a first aspect of the present invention, which solves the above problems, a flow path forming substrate in which a pressure generating chamber communicating with a nozzle opening is defined, and a piezoelectric element provided on the flow path forming substrate via a diaphragm. A liquid ejecting head comprising: a sealing substrate having a sealing portion joined to a surface of the flow path forming substrate on the piezoelectric element side for sealing the piezoelectric element; and forming the flow path of the sealing substrate. A connection wiring for applying a voltage to the piezoelectric element is provided on a surface opposite to a bonding surface with the substrate via an insulating film, and the sealing substrate is formed of a silicon single crystal substrate, and The liquid ejecting head is characterized in that at least one exposed portion from which the insulating film is removed and the sealing substrate is exposed is provided on the surface.
[0013]
In the first aspect, by measuring the resistance value between the exposed portion and the connection wiring, the insulation state between the connection wiring and the sealing substrate can be easily inspected.
[0014]
According to a second aspect of the present invention, there is provided the liquid ejecting head according to the first aspect, wherein two or more of the exposed portions are provided.
[0015]
In the second aspect, by measuring the resistance value between the two exposed portions, erroneous measurement when measuring the resistance value between the exposed portion and the connection wiring is prevented.
[0016]
A third aspect of the present invention is the liquid jet head according to the first or second aspect, wherein the exposed portion is formed by removing a part of the sealing substrate together with the insulating film. It is in.
[0017]
In the third aspect, the surface of the sealing substrate is reliably exposed, and the insulation state between the connection wiring and the sealing substrate can be more accurately inspected.
[0018]
According to a fourth aspect of the present invention, in the liquid ejecting head according to the third aspect, the exposed portion is formed of an inclined surface whose bottom surface is inclined inward.
[0019]
According to the fourth aspect, the probe for inspecting the insulation state between the connection wiring and the sealing substrate can be easily and reliably brought into contact with the sealing substrate.
[0020]
A fifth aspect of the present invention is the liquid jet head according to the third or fourth aspect, wherein the exposed portion is formed by anisotropically etching the sealing substrate.
[0021]
In the fifth aspect, the exposed portion can be formed relatively easily.
[0022]
According to a sixth aspect of the present invention, there is provided a flow channel forming substrate in which a pressure generating chamber communicating with a nozzle opening is defined, a piezoelectric element provided on the flow channel forming substrate via a vibration plate, and the flow channel forming substrate. A sealing substrate having a sealing portion that is bonded to the surface of the piezoelectric element and seals the piezoelectric element, and a surface opposite to a bonding surface of the sealing substrate with the flow path forming substrate. A connection wiring provided through an insulating film for applying a voltage to the piezoelectric element, wherein the sealing substrate is made of a silicon single crystal substrate, and the insulating film is removed from the surface of the sealing substrate; A method for inspecting a liquid ejecting head in which at least one exposed portion is provided, wherein a probe is brought into contact with each of the connection wiring and the exposed portion to measure a resistance value between both probes. Insulation between connection wiring and the sealing substrate In the inspection method for a liquid jet head characterized by having an insulation test step of examining state.
[0023]
In the sixth aspect, the insulation state between the connection wiring and the sealing substrate can be easily and reliably inspected.
[0024]
According to a seventh aspect of the present invention, in the sixth aspect, the sealing substrate is provided with two or more exposed portions, and the probe is brought into contact with each of the two exposed portions before the insulation inspection step. A continuity inspection step of inspecting the continuity of both probes by measuring a resistance value between the two probes.
[0025]
According to the seventh aspect, the reliability of the inspection result in the insulation inspection step is significantly improved.
[0026]
According to an eighth aspect of the present invention, there is provided a flow channel forming substrate in which a pressure generating chamber communicating with a nozzle opening is defined, a piezoelectric element provided on the flow channel forming substrate via a diaphragm, and the flow channel forming substrate. A sealing substrate having a sealing portion that is bonded to the surface of the piezoelectric element and seals the piezoelectric element, and a surface opposite to a bonding surface of the sealing substrate with the flow path forming substrate. A connection wiring provided through an insulating film for applying a voltage to the piezoelectric element, wherein the sealing substrate is made of a silicon single crystal substrate, and the insulating film is removed from the surface of the sealing substrate; Wherein the sealing substrate is thermally oxidized to become the insulating film, and the piezoelectric element holding portion, the connection wiring, and the piezoelectric device are provided. Penetration through which the connection wiring connecting the element is extended Forming a silicon dioxide film serving as a mask pattern for forming a silicon substrate on the surface of the sealing substrate; and patterning the silicon dioxide film to form the piezoelectric element holding portion and the through hole of the silicon dioxide film. Forming an opening in the region to be exposed and forming an exposed opening serving as the exposed portion, forming the wiring pattern on the silicon dioxide film, and using the silicon dioxide film as a mask pattern to form the sealing substrate. Forming the piezoelectric element holding portion and the through hole by etching the substrate, and bonding the sealing substrate and the flow path forming substrate on which the piezoelectric element is formed. A method for manufacturing a liquid jet head.
[0027]
In the eighth aspect, the exposed portion can be formed on the sealing substrate without increasing the number of manufacturing steps.
[0028]
In a ninth aspect of the present invention based on the eighth aspect, in the step of forming the piezoelectric element holding portion and the through hole, the sealing substrate is anisotropically etched from the opening to form the piezoelectric element holding portion. Forming the through hole and anisotropically etching the sealing substrate through the exposed opening to remove a part of the sealing substrate. is there.
[0029]
In the ninth aspect, the exposed portion from which a part of the sealing substrate has been removed can be formed without increasing the number of manufacturing steps.
[0030]
According to a tenth aspect of the present invention, in the ninth aspect, in the step of forming the exposed opening, when the sealing substrate is anisotropically etched through the exposed opening, the sealing substrate is etched. Wherein the exposure opening is formed in such a size as to stop automatically.
[0031]
In the tenth aspect, by forming the exposure opening with a predetermined size, the silicon single crystal substrate serving as the sealing substrate has a predetermined crystal face exposed and etching is automatically stopped. Then, by forming the exposure opening in such a size that the etching is automatically stopped, the exposure portion can be easily formed simultaneously with the through hole and the like.
[0032]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments.
[0033]
(Embodiment 1)
FIG. 1 is an exploded perspective view of the ink jet recording head according to the first embodiment, and FIG. 2 is a schematic plan view of FIG. 1 and a cross-sectional view taken along line AA ′.
[0034]
As shown in the drawing, in this embodiment, the flow path forming substrate 10 is formed of a silicon single crystal substrate having a plane orientation of (110), and has a thickness of 1 to 2 μm made of silicon dioxide formed in advance by thermal oxidation on both surfaces thereof. An elastic film 50 and a protective film 55 are formed respectively. The protective film 55 is used as a mask when forming a pressure generating chamber described later.
[0035]
In the flow path forming substrate 10, pressure generating chambers 12 partitioned by a plurality of partition walls 11 are arranged side by side in the width direction by performing anisotropic etching from the other side. A communication portion 13 that forms a part of a reservoir 100 that is a common ink chamber of the generation chamber 12 is formed, and the communication portion 13 communicates with one longitudinal end of each pressure generation chamber 12 via an ink supply path 14. Have been.
[0036]
Here, the anisotropic etching is performed using the difference in the etching rate of the silicon single crystal substrate. For example, in this embodiment, when a silicon single crystal substrate is immersed in an alkaline solution such as KOH, it is gradually eroded, and the first (111) plane perpendicular to the (110) plane and the first (111) plane And a second (111) plane that forms an angle of about 70 degrees with the (110) plane and forms an angle of about 35 degrees with the (110) plane, and the etching rate of the (111) plane is compared with the etching rate of the (110) plane. The etching is performed using the property that the etching rate is about 1/180. By such anisotropic etching, precision processing can be performed based on depth processing of a parallelogram formed by two first (111) surfaces and two oblique second (111) surfaces. , The pressure generating chambers 12 can be arranged at a high density.
[0037]
In this embodiment, the long side of each pressure generating chamber 12 is formed by the first (111) plane, and the short side is formed by the second (111) plane. The pressure generating chamber 12 is formed by etching until it reaches the elastic film 50 substantially through the flow path forming substrate 10. Here, the amount of the elastic film 50 that is attacked by the alkaline solution for etching the silicon single crystal substrate is extremely small. Further, the cross-sectional area of each ink supply passage 14 communicating with one end of each pressure generating chamber 12 is formed smaller than that of the pressure generating chamber 12 so as to keep the flow resistance of the ink flowing into the pressure generating chamber 12 constant. are doing.
[0038]
The thickness of such a flow path forming substrate 10 may be determined by selecting an optimum thickness in accordance with the arrangement density of the pressure generation chambers 12, and the arrangement density of the pressure generation chambers 12 is, for example, 180 pieces per inch ( If it is about 180 dpi), the thickness of the flow path forming substrate 10 may be about 220 μm. For example, if the flow path forming substrate 10 is arranged at a relatively high density of 200 dpi or more, the thickness of the flow path forming substrate 10 It is preferable that the thickness be relatively thin, 100 μm or less. This is because the arrangement density can be increased while maintaining the rigidity of the partition wall between the adjacent pressure generating chambers 12.
[0039]
On the protective film 55 on the opening side of the flow path forming substrate 10, a nozzle plate 20 having a nozzle opening 21 formed in the pressure generating chamber 12 on the side opposite to the ink supply path 14 is provided with an adhesive. And a heat-sealing film or the like. The nozzle plate 20 has a thickness of, for example, 0.1 to 1 mm, a linear expansion coefficient of 300 ° C. or less, and, for example, 2.5 to 4.5 [× 10 ^-6 / ° C] or non-rust steel. One surface of the nozzle plate 20 entirely covers one surface of the flow path forming substrate 10 and also serves as a reinforcing plate for protecting the silicon single crystal substrate from impact and external force. Further, the nozzle plate 20 may be formed of a material having substantially the same thermal expansion coefficient as the flow path forming substrate 10. In this case, since the deformation of the flow path forming substrate 10 and the nozzle plate 20 due to heat become substantially the same, it is possible to easily join them using a thermosetting adhesive or the like.
[0040]
Here, the size of the pressure generating chamber 12 that applies the ink droplet ejection pressure to the ink and the size of the nozzle opening 21 that ejects the ink droplet are optimized according to the amount of the ejected ink droplet, the ejection speed, and the ejection frequency. You. For example, when recording 360 ink droplets per inch, the nozzle openings 21 need to be formed with a diameter of several tens of μm with high accuracy.
[0041]
On the other hand, the lower electrode film 60 having a thickness of, for example, about 0.2 μm and the thickness of, for example, about 0.5 to 5 μm are formed on the elastic film 50 on the side opposite to the opening surface of the flow path forming substrate 10. The piezoelectric layer 70 and the upper electrode film 80 having a thickness of, for example, about 0.1 μm are laminated and formed by a process to be described later to configure 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. Generally, one of the electrodes of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each of the pressure generating chambers 12. Here, a portion which is constituted by one of the patterned electrodes and the piezoelectric layer 70 and in which a piezoelectric strain is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion. 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. In any case, a piezoelectric active portion is formed for each pressure generating chamber 12. Further, here, the piezoelectric element 300 and a vibration plate whose displacement is generated by driving the piezoelectric element 300 are collectively referred to as a piezoelectric actuator. In the example described above, the elastic film 50 and the lower electrode film 60 function as a diaphragm.
[0042]
Note that a lead electrode 90 made of, for example, gold (Au) and extending to a region facing the ink supply path 14 is connected to each upper electrode film 80 which is an individual electrode of the piezoelectric element 300.
[0043]
On the flow path forming substrate 10 on which the piezoelectric element 300 is formed, the space facing the piezoelectric element 300 can be hermetically sealed with a space that does not hinder the movement of the piezoelectric element 300. A sealing substrate 30 having a suitable piezoelectric element holding portion 31 is joined, and the piezoelectric element 300 is sealed in the piezoelectric element holding portion 31.
[0044]
Further, the sealing substrate 30 is provided with a reservoir portion 32 that constitutes at least a part of the reservoir 100. In the present embodiment, the reservoir portion 32 is formed so as to penetrate the sealing substrate 30 in the thickness direction and to extend in the width direction of the pressure generating chamber 12, and through a communication hole 51 provided in the elastic film 50. Thus, the reservoir 100 communicates with the communication portion 13 of the flow path forming substrate 10 and serves as a common ink chamber for each pressure generating chamber 12.
[0045]
As such a sealing substrate 30, it is preferable to use a material having substantially the same thermal expansion coefficient as that of the flow path forming substrate 10, for example, glass, a ceramic material, or the like. It was formed using a silicon single crystal substrate of the material.
[0046]
In a region between the piezoelectric element holding portion 31 and the reservoir portion 32 of the sealing substrate 30, a through hole 33 penetrating the sealing substrate 30 in the thickness direction is provided. The lead electrode 90 drawn out from each piezoelectric element 300 is exposed in the through hole 33 near the end.
[0047]
An insulating film 35 made of a silicon dioxide film 110 is provided on the surface of the sealing substrate 30, that is, on the surface opposite to the bonding surface with the flow path forming substrate 10. A drive IC (semiconductor integrated circuit) 120 for driving the piezoelectric element 300 is mounted. Specifically, connection wires 130 (first connection wires 131 and second connection wires 132) for connecting each piezoelectric element 300 and the drive IC 120 are formed in a predetermined pattern on the sealing substrate 30. The drive IC 120 is mounted on the connection wiring 130. For example, in the present embodiment, the drive IC 120 is electrically connected to the connection wiring 130 by flip-chip mounting.
[0048]
Note that the lead electrodes 90 drawn out from each piezoelectric element 300 are connected to the first connection wiring 131 by a connection wiring (not shown) extending into the through hole 33 of the sealing substrate 30. An external wiring (not shown) is connected to the second connection wiring 132.
[0049]
In a region of the sealing substrate 30 where the connection wiring 130 is not formed, for example, in the present embodiment, a region near the end opposite to the reservoir 32 of the sealing substrate 30 is a silicon single crystal substrate. An exposed portion 34 from which a certain sealing substrate 30 is exposed is formed in a predetermined size. The exposed portion 34 is used for inspecting the insulation state between the connection wiring 130 and the sealing substrate 30, as will be described in detail later.
[0050]
Such an exposed portion 34 may be formed by removing at least the insulating film 35 and exposing the surface of the sealing substrate 30. In the present embodiment, the exposed portion 34 is formed by removing a part of the sealing substrate 30. ing. The bottom surface of the exposed portion 34 is formed by an inclined surface that is inclined inward. Further, at least one exposed portion 34 may be provided, but in the present embodiment, two exposed portions 34 are provided.
[0051]
Note that a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded to a region corresponding to the reservoir 32 on such a sealing substrate 30. Here, 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), and the sealing film 41 seals one surface of the reservoir 32. Has been stopped. The fixing plate 42 is formed of a hard material such as a metal (for example, stainless steel (SUS) having a thickness of 30 μm). Since a region of the fixing plate 42 facing the reservoir 100 is an opening 43 completely removed in the thickness direction, one surface of the reservoir 100 is sealed only with the sealing film 41 having flexibility. Have been.
[0052]
In such an ink jet recording head of this embodiment, ink is taken in from an external ink supply unit (not shown), the interior is filled with ink from the reservoir 100 to the nozzle opening 21, and then the driving IC 120 is connected via external wiring (not shown). A drive voltage is applied between the lower electrode film 60 and the upper electrode film 80 corresponding to the pressure generating chamber 12 in accordance with the drive signal output from the elastic film 50, the lower electrode film 60, and the piezoelectric layer 70. Due to the bending deformation, the pressure in each pressure generating chamber 12 increases, and ink droplets are ejected from the nozzle openings 21.
[0053]
Hereinafter, a method of manufacturing such an ink jet recording head will be described in order from a method of manufacturing a sealing substrate, with reference to FIGS. FIGS. 3, 6, and 7 are cross-sectional views showing the steps of manufacturing the ink jet recording head, and FIGS. 4 and 5 are schematic views illustrating a method of inspecting the insulation state between the sealing substrate and the connection wiring. .
[0054]
First, as shown in FIG. 3A, a sealing substrate 30 made of a silicon single crystal substrate, in this embodiment, a silicon single crystal substrate having a plane orientation of (110) is thermally oxidized in a diffusion furnace at about 1100 ° C. A silicon dioxide film 110 serving as an insulating film 35 and serving as a mask for etching the sealing substrate 30 is formed on the entire surface.
[0055]
Next, as shown in FIG. 3B, by patterning the silicon dioxide film 110, openings are formed in regions of the sealing substrate 30 where the piezoelectric element holding portion 31, the reservoir portion 32 and the through hole 33 are formed. 111 is formed. The opening 111 corresponding to the piezoelectric element holding portion 31 is formed only on one side of the sealing substrate 30, and the opening 111 corresponding to the reservoir 32 and the through hole 33 is formed on both sides of the sealing substrate 30. Respectively. At the same time, an exposure opening 112 having a predetermined size is formed in a region where the exposure part 34 is formed.
[0056]
Although the details of the exposed opening 112 will be described later, the size of the exposed opening 112 is such that the etching of the sealing substrate 30 is automatically stopped when the sealing substrate 30 is anisotropically etched through the exposed opening 112. It is preferable to form it.
[0057]
Next, as shown in FIG. 3C, a wiring film is formed on the insulating film 35 on the surface of the sealing substrate 30 by, for example, a sputtering method, and then the connection wiring 130 is formed by a roll coater method. The connection wiring 130 may be formed by using a thin film forming method such as a lithography method, for example.
[0058]
Next, as shown in FIG. 3D, the sealing element 30 is anisotropically etched through the silicon dioxide film 110, that is, through the opening 111, thereby forming the piezoelectric element holding portion 31, the reservoir portion 32 and the penetrating portion. A hole 33 is formed. At the same time, a part of the sealing substrate 30 is removed by anisotropically etching the sealing substrate 30 from the exposed opening 112 to form the exposed part 34. Although the sealing substrate 30 is etched through the exposed opening 112, since the exposed opening 112 is formed in a predetermined size as described above, the etching is substantially performed without being etched too deeply. To stop.
[0059]
That is, as described above, when a silicon single crystal substrate having a plane orientation of (110) is anisotropically etched, the first (111) plane perpendicular to the (110) plane and the first (111) plane are approximately Since a second (111) plane that forms an angle of 70 degrees and forms an angle of about 35 degrees with the (110) plane appears, when the second (111) planes cross each other, etching is performed. Stop automatically.
[0060]
Therefore, even if the sealing substrate 30 is continuously etched until the piezoelectric element holding portion 31, the reservoir portion 32, and the through hole 33 are formed, the exposed portion 34 is formed relatively shallow.
[0061]
Further, by forming the sealing substrate 30 in such a process, the exposed portion 34 can be formed simultaneously with the piezoelectric element holding portion 31, the reservoir portion 32, and the through hole 33. That is, there is no need to newly provide a process for forming the exposed portion 34. Therefore, the sealing substrate 30 having the exposed portions 34 can be formed without increasing the manufacturing cost.
[0062]
Next, the insulation state between the sealing substrate 30 and the connection wiring 130 is inspected using, for example, an inspection device having a pair of probe pins. Specifically, as shown in FIG. 4, one probe pin 141 constituting an inspection device (not shown) is brought into contact with the sealing substrate 30 at the exposed portion 34, and the other probe pin 142 is connected to each connection wiring 130, FIG. In step 4, the insulation state between the sealing substrate 30 and the connection wiring 130 is inspected by contacting the second connection wiring 132 and measuring the resistance between the probe pins 141 and 142. That is, it is confirmed that a pinhole or the like is formed in the insulating film 35 and that the connection between the sealing substrate 30 and the connection wiring 130 is not conducted through the pinhole.
[0063]
For example, when the sealing substrate 30 is electrically connected to the connection wiring 130, that is, when a pinhole is formed in the insulating film 35, a resistance value of about 100 kΩ is detected. When both are not conducting, a resistance value of several MΩ is detected.
[0064]
Therefore, by measuring the resistance value between the exposed portion 34 and the connection wiring 130, the insulation state of both can be easily and reliably grasped.
[0065]
Further, in this embodiment, since the exposed portion 34 is formed by removing a part of the sealing substrate 30, the probe pins 141 are reliably brought into contact with the sealing substrate 30 via the exposed portion 34. be able to. Further, in the present embodiment, since the sealing substrate 30 is removed by anisotropic etching to form the exposed portion 34, and the bottom surface thereof is formed with an inclined surface that is inclined inward, the probe pins 141 are formed on the sealing substrate. 30 allows reliable contact and prevents erroneous measurement.
[0066]
Then, as a result of such an insulation inspection process, only products determined to be non-defective are used as products.
[0067]
In the present embodiment, since two exposed portions 34 are provided, a continuity inspection process for inspecting a continuity between the exposed portions 34 may be performed before the insulation inspection process. That is, in this continuity inspection step, as shown in FIG. 5, each of the probe pins 141 and 142 is brought into contact with the sealing substrate 30 via each of the exposed portions 34, and the resistance value between the probe pins 141 and 142 is Is measured.
[0068]
For example, if both probe pins 141 and 142 are conductive, that is, if both probe pins 141 and 142 are in contact with sealing substrate 30, a resistance value of about 100 kΩ is detected. When both are not conducting, that is, when at least one of the probe pins is not in contact with the sealing substrate 30, a resistance value of several MΩ is detected.
[0069]
This makes it possible to easily confirm that the probe pins 141 and 142 are in contact with the sealing substrate 30 via the respective exposed portions 34, thereby preventing erroneous measurement in the insulation inspection process.
[0070]
On the other hand, the flow path forming substrate 10 and the piezoelectric element 300 are formed in the following steps.
[0071]
First, as shown in FIG. 6A, an elastic film 50 and a silicon dioxide film 57 to be the protective film 55 are formed on the surface of the flow path forming substrate wafer to be the flow path forming substrate 10. More specifically, a silicon dioxide film 57 (elastic film 50 and protective film 55) is formed on the entire surface of the wafer for a channel forming substrate made of a silicon single crystal substrate by thermal oxidation in a diffusion furnace at about 1100 ° C.
[0072]
Next, as shown in FIG. 6B, a lower electrode film 60 made of, for example, platinum or the like is formed on the entire surface of the elastic film 50 and then patterned into a predetermined shape.
[0073]
Next, as shown in FIG. 6C, for example, a piezoelectric layer 70 made of, for example, lead zirconate titanate (PZT) and many metals such as aluminum, gold, nickel, and platinum, or conductive materials The upper electrode film 80 made of an oxide or the like is sequentially laminated, and these are simultaneously patterned to form the piezoelectric element 300.
[0074]
Next, as shown in FIG. 6D, for example, a lead electrode 90 made of, for example, gold (Au) is formed over the entire surface of the flow path forming substrate 10 and has a predetermined shape so as to be independent for each piezoelectric element 300. Is patterned.
[0075]
The above is the film forming process. After forming the film in this manner, the pressure generating chamber 12 and the like are formed by anisotropically etching the wafer for the flow path forming substrate with the above-described alkaline solution. That is, as shown in FIG. 7A, the protective film 55 is patterned into a predetermined shape, and the flow path forming substrate 10 is anisotropically etched using the protective film 55 as a mask pattern, thereby forming the pressure generating chambers 12 and The communication section 13 and the ink supply path 14 are formed.
[0076]
Next, as shown in FIG. 7B, the sealing substrate 30 determined to be non-defective in the above-described insulation inspection step is bonded to the surface of the flow path forming substrate 10 on the side of the piezoelectric element 300 with an adhesive or the like. At this time, the communication hole 51 is formed by removing the elastic film 50 and the lower electrode film 60 in the region facing the communication portion 13 by, for example, laser processing.
[0077]
Next, as shown in FIG. 7C, a nozzle plate 20 having a nozzle opening 21 formed on a surface of the flow path forming substrate 10 opposite to the piezoelectric element 300 is bonded with an adhesive or the like. In addition, the compliance substrate 40 including the sealing film 41 and the fixing plate 42 is bonded on the sealing substrate 30 to seal the reservoir 32.
[0078]
Then, the drive IC 120 is mounted on the sealing substrate 30. That is, the driving IC 120 is flip-chip mounted on the first and second connection wirings 131 and 132 and both are electrically connected (see FIG. 2). After that, the ink jet recording head is formed by connecting the lead electrode 90 drawn out from each piezoelectric element 300 and the first connection wiring 131 by wire bonding.
[0079]
In practice, a large number of chips are simultaneously formed on one wafer by the above-described series of film formation and anisotropic etching, and after the process is completed, a flow path of one chip size as shown in FIG. 1 is formed. It is divided for each substrate 10.
[0080]
As described above, in the present embodiment, before joining the flow path forming substrate 10 and the sealing substrate 30, the insulation state between the sealing substrate 30 and the connection wiring 130 is inspected to determine whether the sealing substrate 30 is good. Since the defect can be determined, the yield as a product can be significantly improved. Therefore, the manufacturing cost can be significantly reduced.
[0081]
(Other embodiments)
The embodiment of the present invention has been described above, but the present invention is, of course, not limited to the above embodiment.
[0082]
For example, in the above-described embodiment, two exposed portions are provided. However, at least one exposed portion may be provided, and of course, three or more exposed portions may be provided.
[0083]
Further, for example, in the above-described embodiment, the exposed portion is formed by removing a part of the sealing substrate, but may be an exposed portion from which only the insulating film is removed. In any case, the exposed portion only needs to expose the surface of the sealing substrate.
[0084]
Further, for example, in the above-described embodiment, a silicon single crystal substrate having a plane orientation of (110) is used as the sealing substrate, but a silicon single crystal substrate having a plane orientation of (100) may be used. In addition, the piezoelectric element holding portion and the like are formed by anisotropically etching the sealing substrate. Of course, the piezoelectric element holding portion and the like may be formed by other methods such as dry etching. .
[0085]
Further, for example, in the above-described embodiment, a thin-film type ink jet recording head manufactured by applying a film forming and lithography method has been described as an example. However, the present invention is not limited to this. The present invention can also be applied to a thick-film type ink jet recording head formed by a method such as sticking.
[0086]
Although an ink jet recording head that ejects ink has been described as an example of a liquid ejecting head, the present invention is intended for a wide range of liquid ejecting heads and liquid ejecting apparatuses.
[0087]
As the liquid ejecting head, for example, a recording head used for an image recording apparatus such as a printer, a color material ejecting head used for producing a color filter such as a liquid crystal display, an organic EL display, and an electrode formation such as an FED (surface emitting display). And an organic material ejecting head used for producing a biochip.
[0088]
【The invention's effect】
As described above, in the present invention, connection wiring is provided on the surface of a sealing substrate made of a silicon single crystal substrate via an insulating film, and at least the insulating film is removed on the sealing substrate to remove the surface of the sealing substrate. Is provided, the insulation state between the exposed portion and the connection wiring can be easily inspected. In addition, by inspecting the insulation state of the sealing substrate before joining the sealing substrate and the flow path forming substrate, the yield as a product can be significantly improved, and the manufacturing cost can be significantly reduced. This has the effect.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an ink jet recording head according to a first embodiment of the present invention.
FIG. 2 is a schematic plan view and a cross-sectional view of an ink jet recording head according to Embodiment 1 of the present invention.
FIG. 3 is a sectional view illustrating a manufacturing process of the ink jet recording head according to the first embodiment of the invention.
FIG. 4 is a schematic view illustrating an insulation inspection step of the sealing substrate according to the first embodiment of the present invention.
FIG. 5 is a schematic view illustrating a conduction inspection step of the sealing substrate according to the first embodiment of the present invention.
FIG. 6 is a cross-sectional view illustrating a process of manufacturing the ink jet recording head according to the first embodiment of the present invention.
FIG. 7 is a cross-sectional view illustrating a process of manufacturing the ink jet recording head according to the first embodiment of the present invention.
[Explanation of symbols]
10. Flow path forming substrate
12 Pressure generating chamber
20 Nozzle plate
21 Nozzle opening
30 sealing substrate
31 piezoelectric element holder
32 reservoir
33 Through hole
34 Exposed part
35 Insulating film
40 Compliance Board
60 Lower electrode film
70 Piezoelectric layer
80 Upper electrode film
90 Lead electrode
100 reservoir
110 silicon dioxide film
120 Drive IC
130 Connection wiring
131 first connection wiring
132 second connection wiring
300 piezoelectric element

Claims (10)

In a liquid ejecting head including a flow path forming substrate in which a pressure generation chamber communicating with the nozzle opening is defined, and a piezoelectric element provided on the flow path forming substrate via a vibration plate,
A sealing substrate having a sealing portion that is joined to the surface of the flow path forming substrate on the side of the piezoelectric element and seals the piezoelectric element, and a bonding surface of the sealing substrate with the flow path forming substrate A connection wiring is provided on an opposite surface via an insulating film to apply a voltage to the piezoelectric element, and the sealing substrate is made of a silicon single crystal substrate, and the insulating film is removed on the surface thereof. A liquid ejecting head, wherein at least one exposed portion where the sealing substrate is exposed is provided. 2. The liquid jet head according to claim 1, wherein two or more of the exposed portions are provided. 3. The liquid jet head according to claim 1, wherein the exposed portion is formed by removing a part of the sealing substrate together with the insulating film. 4. The liquid ejecting head according to claim 3, wherein the exposed portion is formed by an inclined surface having a bottom surface inclined inward. 5. The liquid jet head according to claim 3, wherein the exposed portion is formed by anisotropically etching the sealing substrate. A flow path forming substrate in which a pressure generating chamber communicating with the nozzle opening is defined; a piezoelectric element provided on the flow path forming substrate via a vibration plate; and a surface joined to the piezoelectric element side of the flow path forming substrate And a sealing substrate having a sealing portion for sealing the piezoelectric element, and provided on a surface of the sealing substrate opposite to a bonding surface with the flow path forming substrate via an insulating film. At least one exposed portion having connection wiring for applying a voltage to the piezoelectric element, wherein the sealing substrate is made of a silicon single crystal substrate and the insulating film is removed from the surface thereof to expose the sealing substrate. An inspection method for a provided liquid jet head,
An insulation inspection step of inspecting an insulation state between the connection wiring and the sealing substrate by measuring a resistance value between the two probes by contacting a probe with the connection wiring and the exposed portion, respectively. Inspection method for liquid jet head. 7. The sealing substrate according to claim 6, wherein two or more exposed portions are provided on the sealing substrate, and before the insulation inspection step, a probe is brought into contact with each of the two exposed portions to measure a resistance value between the two probes. A method for inspecting the continuity of both probes. A flow path forming substrate in which a pressure generating chamber communicating with the nozzle opening is defined; a piezoelectric element provided on the flow path forming substrate via a vibration plate; and a surface joined to the piezoelectric element side of the flow path forming substrate And a sealing substrate having a sealing portion for sealing the piezoelectric element, and provided on a surface of the sealing substrate opposite to a bonding surface with the flow path forming substrate via an insulating film. At least one exposed portion having connection wiring for applying a voltage to the piezoelectric element, wherein the sealing substrate is made of a silicon single crystal substrate and the insulating film is removed from the surface thereof to expose the sealing substrate. A method for manufacturing a liquid jet head provided,
The sealing substrate is thermally oxidized to become the insulating film, and also to become a mask pattern for forming a through-hole in which the piezoelectric element holding portion and the connection wiring for connecting the connection wiring and the piezoelectric element are extended. Forming a silicon dioxide film on the surface of the sealing substrate; patterning the silicon dioxide film to form an opening in a region of the silicon dioxide film where the piezoelectric element holding portion and the through hole are formed; Forming an exposed opening serving as the exposed portion, forming the wiring pattern on the silicon dioxide film, and etching the sealing substrate by using the silicon dioxide film as a mask pattern to hold the piezoelectric element. Forming a portion and the through hole, and joining the sealing substrate and the flow path forming substrate on which the piezoelectric element is formed. The method of manufacturing a liquid jet head, wherein the door. 9. The method according to claim 8, wherein, in the step of forming the piezoelectric element holding portion and the through hole, the sealing element is anisotropically etched from the opening to form the piezoelectric element holding portion and the through hole. A method for manufacturing a liquid jet head, comprising: removing a part of the sealing substrate by anisotropically etching the sealing substrate through an exposed opening. 10. The method according to claim 9, wherein in the step of forming the exposed opening, the etching of the sealing substrate is automatically stopped when the sealing substrate is anisotropically etched through the exposed opening. Forming the exposure opening by using the above method.

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