JP2008124343A - Manufacturing method of actuator device and manufacturing method of liquid injection head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an actuator device in which a characteristic of a piezoelectric element is made uniform and a manufacturing method of a liquid injection head. <P>SOLUTION: The method comprises a process for forming a test pattern 400 which is electrically discontinuous with an electrode of the piezoelectric element and has the same layer as an upper electrode of the piezoelectric element on a substrate, covering the test pattern with a protection film 200 covering the piezoelectric element, simultaneously etching a region facing the upper electrode of the test pattern 400 of the protection film 200 with an opening part formed in the protection film 200 so as to form an inspection opening part 204, measuring an electric resistance value of the upper electrode of the test pattern 400 in a first state where the inspection opening part 204 is not formed in the test pattern 400, measuring the electric resistance value of the upper electrode of the test pattern 400 in a second state where the protection film 200 having the inspection opening part 204 is formed in the test pattern 400 and acquiring etching quantity of the upper electrode based on the electric resistance value in the first state and the electric resistance value in the second state. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an actuator device having a piezoelectric element that is displaceably provided on a substrate, and a method for manufacturing a liquid ejecting head that includes an actuator device as liquid ejecting means that ejects liquid from a nozzle opening.

  The piezoelectric element used in the actuator device includes a piezoelectric material exhibiting an electromechanical conversion function, for example, a piezoelectric layer made of a crystallized dielectric material sandwiched between two electrodes, a lower electrode and an upper electrode There is. Such an actuator device is generally called a flexural vibration mode actuator device, and is used by being mounted on, for example, a liquid ejecting head or the like. As a typical example of the liquid ejecting head, for example, a part of the pressure generating chamber communicating with the nozzle opening for ejecting ink droplets is configured by a diaphragm, and the diaphragm is deformed by a piezoelectric element to There are ink jet recording heads that pressurize ink and eject ink droplets from nozzle openings. In addition, as an actuator device mounted on an ink jet recording head, for example, a uniform piezoelectric material layer is formed over the entire surface of the diaphragm by a film forming technique, and this piezoelectric material layer is formed into a pressure generating chamber by a lithography method. There is one in which a piezoelectric element is formed so as to be separated into a corresponding shape and independent for each pressure generation chamber (for example, see Patent Document 1).

  In addition, as a head structure that prevents the piezoelectric element from being destroyed and does not hinder the deformation of the piezoelectric element, the piezoelectric element is covered with a protective film made of an insulator, and is formed in a region corresponding to the main part of the upper electrode of the protective film. Some have an opening (see, for example, Patent Document 2).

  According to such a configuration, the displacement amount of the piezoelectric element can be ensured by providing the opening in the protective film that inhibits the displacement of the piezoelectric element.

JP 2003-127366 A (pages 4-7, FIGS. 1-4) Japanese Patent No. 3552013 (pages 4-5, FIG. 4)

  The opening of the protective film as in Patent Document 2 is generally formed by etching such as dry etching, and overetched until reaching the surface of the upper electrode so that the protective film does not remain in the opening. Is done.

  However, when the opening of the protective film is formed by etching, the surface of the upper electrode is also over-etched at the same time. There is a problem that variations occur and variations occur in the displacement characteristics of the piezoelectric elements.

  In addition, if the amount of etching in which the upper electrode is over-etched varies among a plurality of liquid ejecting heads, the head unit liquid ejecting characteristics vary when a head unit is formed by combining a plurality of liquid ejecting heads. There is a problem of end.

  Furthermore, the measurement of the etching amount in which the upper electrode is over-etched can only be performed by cutting the piezoelectric element, which increases the cost.

  In view of such circumstances, the present invention provides a method for manufacturing an actuator device and a method for manufacturing a liquid jet head in which an etching amount obtained by over-etching an upper electrode can be obtained, and characteristics of piezoelectric elements are uniformized. For the purpose.

  In an aspect of the present invention, a piezoelectric element including a lower electrode, a piezoelectric layer, and an upper electrode is formed on one surface of a substrate, a protective film made of an insulating material covering the piezoelectric element is formed, and then the upper surface of the protective film is An actuator device manufacturing method for forming an opening exposing the upper electrode by etching a region facing the electrode, wherein the actuator device is electrically discontinuous with the electrode of the piezoelectric element on the substrate, and A test pattern having the same layer as the upper electrode is formed, the test pattern is covered with the protective film covering the piezoelectric element, and a region of the protective film facing the upper electrode of the test pattern is formed in the opening. At the same time, an inspection opening exposing the upper electrode is formed by etching, and the test pattern is in a first state where the inspection opening is not formed in the test pattern. Measure the electrical resistance value of the upper electrode, measure the electrical resistance value of the upper electrode of the test pattern in the second state in which the protective film having the inspection opening is formed in the test pattern, An actuator device comprising a step of obtaining an etching amount of the upper electrode when the opening is formed based on the electrical resistance value in the first state and the second electrical resistance value It is in the manufacturing method.

  In this aspect, the upper amount of the piezoelectric element is obtained by obtaining the etching amount by which the upper electrode of the test pattern is etched based on the electric resistance value in the first state of the test pattern and the electric resistance value in the second state. The amount of etching in which the electrode is over-etched can be grasped. As a result, the displacement characteristics of the piezoelectric elements due to the etching amount of the upper electrode of the piezoelectric elements can be grasped, and the actuator devices can be ranked based on the displacement characteristics of the piezoelectric elements. Therefore, a plurality of actuator devices in which the displacement characteristics of the piezoelectric elements are made uniform can be obtained.

  Here, the second state is a state in which two or more terminal exposed portions exposing the upper electrode are formed outside the inspection opening of the protective film covering the test pattern, and the electrical resistance It is preferable to measure the value at the terminal exposed portion. According to this, by measuring the electrical resistance value of the upper electrode exposed by the terminal exposed portion, it is possible to reduce a measurement error due to a shift in the measurement position.

  Moreover, it is preferable that the said test pattern is comprised by the same layer as the said lower electrode, the said piezoelectric material layer, and the said upper electrode. According to this, by forming the test pattern with the same configuration as the piezoelectric element, the film formation condition of the piezoelectric element and the film formation condition of the test pattern are made the same, and the etching amount obtained by overetching the upper electrode is more accurate. Can be measured.

  Moreover, it is preferable to measure the electrical resistance value of the test pattern by a four-terminal method. According to this, the electrical resistance value of a thin film such as the upper electrode used in the actuator device can be measured with high accuracy.

  Moreover, it is preferable that the first state is a state before forming the protective film covering the piezoelectric element and the test pattern. According to this, since the same test pattern can be set to the first state and the second state, the test pattern can be formed in a small area, and the restriction of the test pattern formation position is reduced.

  Further, two test patterns are formed, and the first state is a state in which the protective film in which the inspection opening is not provided is formed in one test pattern, and the second state. However, it is preferable that the protective film provided with the inspection opening is formed on the other test pattern. According to this, when the probe is brought into contact with the test pattern before forming the protective film, the upper electrode is damaged, and when the subsequent protective film is formed, the upper electrode is peeled off and foreign matter is generated. Can be reliably prevented. Further, when the protective film is formed by sputtering after measuring the electrical resistance value of the test pattern in the first state, the upper electrode of the test pattern is etched by reverse sputtering, so that the electrical resistance value in the first state and the first resistance value For the difference from the electrical resistance value in the state of 2, the value obtained by adding the etching amount of the reverse sputtering in addition to the etching amount when the opening is formed in the protective film is measured. By providing, it is possible to prevent an error from occurring in the acquired etching amount.

  Further, as the test pattern, the upper electrode is formed in a cross shape, and in the first state, one test pattern is covered with the protective film, and a terminal exposed portion that exposes four end portions of the test pattern In the second state, the other test pattern is covered with the protective film, and the terminal exposed portion exposing the four end portions of the test pattern and the cross-shaped crossing region are exposed. In the state in which the inspection opening is formed, an electric current is passed through a pair of adjacent ends exposed by the terminal exposed portions of the two test patterns, and a potential difference between the other ends is measured. It is preferable to measure the resistance value. According to this, since it is possible to measure only the electrical resistance value in the region where the cross shape of the test pattern intersects, it is possible to perform high-accuracy measurement by preventing errors in the electrical resistance value due to the influence of other regions. it can.

  In addition, a lead-out wiring led out from the piezoelectric element is formed, and the upper electrode exposed by the terminal exposed portion of the test pattern is made of the same layer as the lead-out wiring and is electrically non-conductive with the lead-out wiring. After the formation of the continuous test lead wiring, it is preferable that the electrical resistance values of the test pattern in the first state and the second state are measured via the test lead wiring. According to this, the timing for measuring the electrical resistance value of the test pattern is not limited, and the final thickness of the upper electrode can be grasped.

  Moreover, it is preferable to control the etching amount of the opening by feeding back the etching amount acquired in the step of acquiring the etching amount of the upper electrode. According to this, an actuator device having a piezoelectric element in which the etching amount of the upper electrode is made uniform and the displacement characteristics are made uniform by controlling the etching amount for etching the protective film by feeding back the obtained etching amount. Can be formed.

  Furthermore, the present invention is characterized in that the actuator device is formed on one surface of a flow path forming substrate provided with a pressure generating chamber communicating with a nozzle opening for ejecting liquid by the method for manufacturing an actuator device of the above aspect. A method of manufacturing a liquid jet head. According to this, since the liquid ejecting characteristics of the liquid ejecting head can be made uniform, when the head unit is formed by combining a plurality of liquid ejecting heads, the liquid ejecting characteristics are made uniform, and high accuracy and high quality are achieved. Printing can be performed.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
FIG. 1 is an exploded perspective view showing a schematic configuration of an ink jet recording head which is an example of a liquid ejecting head according to Embodiment 1 of the present invention. FIG. 2 is a plan view of a flow path forming substrate and the ink jet recording head. It is sectional drawing of the longitudinal direction of this pressure generation chamber.

  As shown in the figure, the flow path forming substrate 10 is composed of a silicon single crystal substrate whose crystal plane orientation in the thickness direction is a (110) plane in this embodiment, and one surface thereof is previously composed of silicon dioxide by thermal oxidation. An elastic film 50 having a thickness of 0.5 to 2 μm is formed.

  In the flow path forming substrate 10, pressure generating chambers 12 partitioned by a plurality of partition walls 11 are arranged in parallel in the width direction (short direction) by anisotropic etching from the other surface side. In addition, an ink supply path 14 and a communication path 15 are partitioned by a partition wall 11 on one end side in the longitudinal direction of the pressure generating chamber 12 of the flow path forming substrate 10. In addition, a communication portion 13 constituting a part of the reservoir 100 serving as an ink chamber (liquid chamber) common to the pressure generation chambers 12 is formed at one end of the communication passage 15. That is, the flow path forming substrate 10 is provided with a liquid flow path including a pressure generation chamber 12, a communication portion 13, an ink supply path 14, and a communication path 15.

  The ink supply path 14 communicates with one end side in the longitudinal direction of the pressure generation chamber 12 and has a smaller cross-sectional area than the pressure generation chamber 12. For example, in the present embodiment, the ink supply path 14 has a width smaller than the width of the pressure generation chamber 12 by narrowing the flow path on the pressure generation chamber 12 side between the reservoir 100 and each pressure generation chamber 12 in the width direction. It is formed with. As described above, in this embodiment, the ink supply path 14 is formed by narrowing the width of the flow path from one side. However, the ink supply path may be formed by narrowing the width of the flow path from both sides. Further, the ink supply path may be formed by narrowing from the thickness direction instead of narrowing the width of the flow path. Further, each communication path 15 communicates with the side of the ink supply path 14 opposite to the pressure generation chamber 12 and has a larger cross-sectional area than the width direction (short direction) of the ink supply path 14. In this embodiment, the communication passage 15 is formed with the same cross-sectional area as the pressure generation chamber 12.

  In other words, the flow path forming substrate 10 is connected to the pressure generation chamber 12, the ink supply path 14 having a smaller cross-sectional area in the short direction of the pressure generation chamber 12, the ink supply path 14, and the ink supply. A communication passage 15 having a cross-sectional area larger than the cross-sectional area in the short direction of the path 14 is provided by being partitioned by a plurality of partition walls 11.

Further, 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 a heat-welded 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, an elastic film 50 made of silicon dioxide and having a thickness of, for example, about 1.0 μm is formed on the side opposite to the opening surface of the flow path forming substrate 10. An insulator film 55 made of zirconium oxide (ZrO ₂ ) or the like and having a thickness of, for example, about 0.4 μm is laminated. On the insulator film 55, the lower electrode film 60 having a thickness of about 0.1 to 0.5 μm and lead zirconate titanate (PZT) which is an example of a piezoelectric film are formed. For example, the piezoelectric layer 300 is formed by laminating a piezoelectric layer 70 having a thickness of about 1.1 μm and an upper electrode film 80 having a thickness of, for example, about 0.05 μm by a process described later. 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 addition, here, a portion that is configured by any one of the patterned electrodes and the piezoelectric layer 70 and in which piezoelectric distortion 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. However, there is no problem even if this is reversed for convenience of a drive circuit and wiring. In addition, here, the piezoelectric element 300 and the diaphragm that is displaced by driving the piezoelectric element 300 are collectively referred to as an actuator device. In the above-described example, the elastic film 50, the insulator film 55, and the lower electrode film 60 function as a diaphragm. However, the elastic film 50 and the insulator film 55 are not provided, and only the lower electrode film 60 is left. The electrode film 60 may be a diaphragm. Further, the piezoelectric element 300 itself may substantially serve as a diaphragm.

  Examples of the material of the piezoelectric layer 70 constituting the piezoelectric element 300 include a ferroelectric piezoelectric material such as lead zirconate titanate (PZT), niobium, nickel, magnesium, bismuth, yttrium, and the like. A relaxor ferroelectric or the like to which any of the above metals is added is used.

  The piezoelectric element 300 is covered with a protective film 200 made of an insulating material having moisture resistance. In the present embodiment, the protective film 200 is provided so as to cover the side surfaces of the piezoelectric layer 70, the side surfaces of the upper electrode film 80, and the peripheral edge of the upper surface, and continuously over the plurality of piezoelectric elements 300. That is, the main part, which is a substantially central region on the upper surface of the upper electrode film 80, is not provided with the protective film 200, but is provided with an opening 201 that opens the main part of the upper surface of the upper electrode film 80.

  The opening 201 penetrates the protective film 200 in the thickness direction and opens in a rectangular shape along the longitudinal direction of the piezoelectric element 300. For example, the protective film 200 extends over the entire surface of the flow path forming substrate 10. Then, the protective film 200 can be selectively formed by dry etching such as ion milling or reactive dry etching.

By covering the piezoelectric element 300 with the protective film 200 in this way, it is possible to prevent the piezoelectric element 300 from being damaged due to moisture in the atmosphere. Here, the material of the protective film 200 may be any material having moisture resistance. For example, inorganic materials such as silicon oxide (SiO _x ), tantalum oxide (TaO _x ), and aluminum oxide (AlO _x ) are used. It is preferable to use an insulating material, and in particular, it is preferable to use aluminum oxide (AlO _x ), for example, alumina (Al ₂ O ₃ ), which is an inorganic amorphous material. When aluminum oxide is used as the material of the protective film 200, moisture permeation in a high humidity environment can be sufficiently prevented even if the protective film 200 has a relatively thin film thickness of about 100 nm. In the present embodiment, alumina (Al ₂ O ₃ ) is used as the protective film 200.

  In addition, by providing the opening 201 in the protective film 200, it is possible to satisfactorily maintain the ink ejection characteristics without hindering the displacement of the piezoelectric element 300 (piezoelectric active portion).

  The protective film 200 may be provided so as to cover at least the surface of the piezoelectric layer 70 of the piezoelectric element 300. A protective film is provided for each piezoelectric element 300 and is discontinuous across the plurality of piezoelectric elements 300. You may do it.

  On the protective film 200, for example, a lead electrode 90 made of gold (Au) or the like is provided. The lead electrode 90 has one end connected to the upper electrode film 80 through a connection hole 202 provided in the protective film 200 and the other end extended to the ink supply path 14 side of the flow path forming substrate 10. The extended tip portion is connected to a drive circuit 120 that drives a piezoelectric element 300 described later via a connection wiring 121.

  In addition, a test pattern 400 is provided on the flow path forming substrate 10 to measure an etching amount obtained by over-etching the upper electrode film 60 when the opening 201 of the protective film 200 is formed. Details of the test pattern 400 will be described later.

  Further, on the flow path forming substrate 10 on which the piezoelectric element 300 is formed, a protective substrate 30 provided with a reservoir portion 31 in a region facing the communication portion 13 is bonded via an adhesive 35. As described above, the reservoir unit 31 communicates with the communication unit 13 of the flow path forming substrate 10 and constitutes the reservoir 100 serving as a common liquid chamber for the pressure generation chambers 12. Alternatively, the communication portion 13 of the flow path forming substrate 10 may be divided into a plurality of pressure generation chambers 12 and only the reservoir portion 31 may be used as the reservoir. Further, for example, only the pressure generation chamber 12 is provided in the flow path forming substrate 10, and a reservoir and a member interposed between the flow path forming substrate 10 and the protective substrate 30 (for example, the elastic film 50, the insulator film 55, etc.) An ink supply path 14 that communicates with each pressure generating chamber 12 may be provided.

  Further, the protective substrate 30 is provided with a piezoelectric element holding portion 32 having a space that does not hinder the movement of the piezoelectric element 300 in a region facing the piezoelectric element 300. In addition, the piezoelectric element holding part 32 should just have a space of the grade which does not inhibit the motion of the piezoelectric element 300, and the said space may be sealed or may not be sealed.

  Further, a through hole 33 that penetrates the protective substrate 30 in the thickness direction is provided in a region between the piezoelectric element holding portion 32 and the reservoir portion 31 of the protective substrate 30, and the lower electrode film 60 is provided in the through hole 33. And the tip of the lead electrode 90 are exposed.

  A drive circuit 120 for driving the piezoelectric element 300 is mounted on the protective substrate 30. For example, a circuit board or a semiconductor integrated circuit (IC) can be used as the drive circuit 120. The drive circuit 120 and the lead electrode 90 are electrically connected via a connection wiring 121 made of a conductive wire such as a bonding wire.

  As the protective substrate 30, it is preferable to use a material substantially the same as the coefficient of thermal expansion of the flow path forming substrate 10, for example, glass, a ceramic material, etc. In this embodiment, the surface orientation of the same material as the flow path forming substrate 10 is used. It was formed using a (110) silicon single crystal substrate.

  A compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded onto the protective 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 portion 31. It has been stopped. 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 such an ink jet recording head of this embodiment, ink is taken in from an external ink supply means (not shown), filled with ink from the reservoir 100 to the nozzle opening 21, and then in accordance with a recording signal from the drive circuit 120. Applying a voltage between each of the lower electrode film 60 and the upper electrode film 80 corresponding to the pressure generation chamber 12 to bend and deform the elastic film 50, the insulator film 55, the lower electrode film 60, and the piezoelectric layer 70. As a result, the pressure in each pressure generating chamber 12 increases and ink droplets are ejected from the nozzle openings 21.

  Here, a manufacturing method of the ink jet recording head will be described with reference to FIGS. 3, 4, 8, and 9 are cross-sectional views in the longitudinal direction of the pressure generating chamber, and FIG. 5 is a plan view of the flow path forming substrate wafer and an enlarged plan view of the main part thereof. FIG. 6 is an enlarged plan view of the main part of the flow path forming substrate wafer and its BB ′ sectional view, and FIG. 7 is an enlarged plan view of the main part of the flow path forming substrate wafer. is there.

  First, as shown in FIG. 3A, a flow path forming substrate wafer 110 made of a silicon wafer in which a plurality of flow path forming substrates 10 are integrally formed is thermally oxidized in a diffusion furnace at about 1100 ° C. A silicon dioxide film 51 constituting the elastic film 50 is formed on the surface.

Next, as shown in FIG. 3B, an insulator film 55 made of zirconium oxide is formed on the elastic film 50 (silicon dioxide film 51). Specifically, a zirconium (Zr) layer is formed on the elastic film 50 (silicon dioxide film 51) by, for example, sputtering, and then the zirconium layer is thermally oxidized in a diffusion furnace to form zirconium oxide (ZrO ₂ ). An insulator film 55 made of is formed.

  Next, as shown in FIG. 3C, after the lower electrode film 60 is formed by stacking platinum and iridium on the insulator film 55, for example, the lower electrode film 60 is patterned into a predetermined shape. The lower electrode film 60 is not limited to a laminate of platinum (Pt) and iridium (Ir), and an alloy of these may be used. Further, the lower electrode film 60 may be used as a single layer of any one of platinum (Pt) and iridium (Ir), and a metal or a metal oxide other than these materials may be used. Also good.

  Next, as shown in FIG. 4A, a piezoelectric layer 70 made of, for example, lead zirconate titanate (PZT) and an upper electrode film 80 made of, for example, iridium are formed on the entire surface of the flow path forming substrate 10. Then, as shown in FIG. 4B, the piezoelectric element 300 is formed by patterning in a region facing each pressure generating chamber 12. As a material of the piezoelectric layer 70 constituting the piezoelectric element 300, for example, a ferroelectric piezoelectric material such as lead zirconate titanate (PZT) or a metal such as niobium, nickel, magnesium, bismuth or yttrium is used. An added relaxor ferroelectric or the like is used. In the present embodiment, the piezoelectric layer 70 is formed by applying a so-called sol in which a metal organic material is dissolved and dispersed in a solvent, drying it to gel, and baking it at a high temperature to form a piezoelectric layer made of a metal oxide. The piezoelectric layer 70 was formed using a so-called sol-gel method to obtain 70. The method for forming the piezoelectric layer 70 is not particularly limited, and for example, a MOD method, a sputtering method, or the like may be used.

  Further, a test pattern 400 is formed on the flow path forming substrate wafer 110 to measure the etching amount obtained by over-etching the upper electrode film 60 when the opening 201 of the protective film 200 is formed in a later step.

  In the present embodiment, as shown in FIG. 5A, when the piezoelectric element 300 is patterned by etching, the test pattern 400 is formed by simultaneously etching the piezoelectric layer 70 and the upper electrode film 80. In addition, the test pattern 400 is provided on the lower electrode film 60 on one side in the direction in which the piezoelectric elements 300 are juxtaposed in the region to be the flow path forming substrate 10 of the flow path forming substrate wafer 110.

  As the test pattern 400, as shown in FIG. 5B, a first test pattern 401 and a second test pattern 402 are formed. In the present embodiment, the first test pattern 401 and the second test pattern 402 are formed so as to have a cross shape when viewed in plan. That is, the first test pattern 401 and the second test pattern 402 constituting the test pattern 400 have a van der Pol structure.

  Further, since the test pattern 400 is formed by etching the piezoelectric layer 70 and the upper electrode film 80, the test pattern 400 includes the same layer as the piezoelectric layer 70 of the piezoelectric element 300 as shown in FIG. In addition, the piezoelectric layer 300 is discontinuous with the piezoelectric layer 70 and the upper electrode film 80 of the piezoelectric element 300 is the same layer and is electrically discontinuous with the electrodes 60 and 80 of the piezoelectric element 300. It consists of and.

  Next, as shown in FIG. 4C, after forming the protective film 200 on the entire surface of the flow path forming substrate wafer 110, the openings 201 are etched by etching the regions corresponding to the piezoelectric elements 300 of the protective film 200. And the connection hole 202 is formed. The protective film 200 can be etched by dry etching such as ion milling or reactive dry etching (RIE).

  Further, as shown in FIG. 6, a region corresponding to the test pattern 400 of the protective film 200 is simultaneously etched to form the terminal exposed portion 203 and the inspection opening 204.

  The terminal exposed portion 203 exposes each end portion of the upper electrode film 80 of the test pattern 400. That is, four terminal exposed portions 203 are provided for each of the first test pattern 203 and the second test pattern 203.

  The inspection opening 204 opens a region where the cross shape of the second test pattern 402 intersects, and is formed only in the protective film 200 that covers the second test pattern 402. As a result, the terminal exposed portion 203 of the second test pattern 402 is provided outside the inspection opening 204.

  In the present embodiment, the state in which only the terminal exposed portion 203 is provided in the first test pattern 401 is the first state, and the state in which the terminal exposed portion 203 and the inspection opening 204 are provided in the second test pattern 402. The second state is set.

  Then, the protective film 200 is etched until the upper electrode film 80 of the piezoelectric element 300 and the upper electrode film 80 of the test pattern 400 are exposed. Thus, the upper electrode film 80 of the piezoelectric element 300 and the upper electrode film 80 of the test pattern 400 are etched by forming the opening 201, the connection hole 202, the terminal exposed portion 203, and the inspection opening 204 in the protective film 200. Are partially over-etched in the thickness direction. The etching amount by which the upper electrode film 80 of the test pattern 400 is over-etched is the same as the etching amount by which the upper electrode film 80 of the piezoelectric element 300 is over-etched.

  That is, the etching amount overetched when the upper electrode film 80 of the second test pattern 402 forms the inspection opening 204 is larger than the etching amount when the upper electrode film 80 of the piezoelectric element 300 forms the opening 201. The amount is the same as the etched amount. On the other hand, since the inspection opening 204 is not formed in the protective film 200 of the first test pattern 401 in the first state, the upper electrode film 80 of the second test pattern 401 is The region where the cross shape intersects is not over-etched. The upper electrode film 60 corresponding to the terminal exposed portion 203 of the first test pattern 401 and the second test pattern 402 is over-etched in the same manner as the inspection opening 204, but the test pattern is formed in a later step. There is no influence when measuring the electrical resistance value of the upper electrode film 80 of 400.

  Next, the electrical resistance value of each upper electrode film 80 of the test pattern 400 is measured. Specifically, as shown in FIG. 7, a current is passed through two adjacent end portions of the upper electrode film 80 of the first test pattern 401 in the first state, and the other two end portions of the upper electrode film 80. The electrical resistance value of the upper electrode film 80 is measured by measuring the potential difference between them. That is, the electric resistance value is calculated from the measured current and voltage (potential difference) according to Ohm's law. Also, the electrical resistance value of the upper electrode film 80 of the second test pattern 402 in the second state is measured in the same manner as the first test pattern 401.

  The measurement of the electrical resistance value of each upper electrode film 80 of the test pattern 400 can be performed, for example, by bringing a probe directly into contact with the end portion of each upper electrode film 80 of the test pattern 400.

  Such measurement of the electric resistance value is generally called a four-terminal method (four deep needle method), and the electric resistance value of the upper electrode film 80 of the thin film used for the piezoelectric element 300 is measured. It is useful for. Further, by measuring the four ends of the upper electrode film 80 of the test pattern 400 having a cross shape (van der Pol structure) as in the present embodiment by the four-terminal method (four deep needle method), the test pattern 400 The electric resistance value of only the region where the cross shape of the upper electrode film 80 intersects can be measured.

  Thus, the upper electrode film 80 of the first test pattern 401 in the first state is not over-etched and the upper electrode film 80 of the second test pattern 402 in the second state is over-etched. By measuring the electrical resistance value with respect to the region, the amount of overetching of the upper electrode film 80 of the second test pattern 402 in the second state can be obtained. That is, since the electrical resistance value of the upper electrode film 80 is inversely proportional to the cross-sectional area, the thickness of the upper electrode film 80 of the second test pattern 402 is larger than the thickness of the upper electrode film 80 of the first test pattern 401. The thickness is small, and the electrical resistance value of the second test pattern 402 is larger than the electrical resistance value of the first test pattern 401. If the difference between the electrical resistance value of the first test pattern 401 and the electrical resistance value of the second test pattern 402 is large, the etching amount by which the second test pattern 402 is over-etched is large (the upper electrode film 80). If the difference in electrical resistance value is small, it can be seen that the etching amount by which the second test pattern 402 is over-etched is small (the thickness of the upper electrode film 80 is thick).

  Thus, by acquiring the etching amount of the second test pattern 402, the etching amount in which the upper electrode film 60 is over-etched when the opening 201 is formed in the protective film 200 corresponding to the piezoelectric element 300 is acquired. can do.

  Incidentally, the rigidity of the entire piezoelectric element 300 changes depending on the etching amount by which the upper electrode film 80 is over-etched, or the electric field strength applied to the piezoelectric element 300 changes depending on the change in the electrical resistance value of the upper electrode film 80. For example, the displacement characteristics of the piezoelectric element 300 change.

  For this reason, the etching amount by which the upper electrode film 80 of the piezoelectric element 300 is etched as in the present invention is acquired by the test pattern 400, and the displacement amount of the piezoelectric element 300 is evaluated based on the etching amount of the upper electrode film 80. Thus, the ink jet recording heads can be ranked based on the displacement amount of the piezoelectric element 300. In addition, by acquiring the etching amount of the upper electrode film 80 and controlling the etching amount for etching the protective film 200 by feeding back the acquired etching amount, the etching amount of the upper electrode film 80 is made uniform. A head can be formed. That is, by controlling the etching amount of the upper electrode film 80 in the next flow path forming substrate wafer 110 based on the etching amount of the upper electrode film 80 in the flow path forming substrate wafer 110 acquired in the first time. An ink jet recording head in which the displacement characteristics of the piezoelectric element 300 are made uniform can be formed from a plurality of flow path forming substrate wafers 110.

  Therefore, when an ink jet recording head unit is manufactured by combining a plurality of ink jet recording heads, the ink ejection characteristics (liquid ejection characteristics) of the ink jet recording head can be made uniform, and the ink jet recording head unit has high accuracy. In addition, high-quality printing can be performed.

  Further, as in this embodiment, by providing the test pattern 400 in each of the regions to be the flow path forming substrates 10, variation in the etching amount of the upper electrode film 80 in the plane of the flow path forming substrate wafer 110. Therefore, the amount of etching of the upper electrode film 80 in the plane of the next flow path forming substrate wafer 110 is controlled, and the displacement of the piezoelectric element 300 from one flow path forming substrate wafer 110 is controlled. A plurality of ink jet recording heads having uniform characteristics can be manufactured. Therefore, the amount of etching of the upper electrode film 80 in the plane of the flow path forming substrate wafer 110 can be made uniform, and the displacement amount of the piezoelectric element 300 can be made uniform. A plurality of ink jet recording heads formed from 110 can be combined to form one head unit. Thereby, yield can be improved and cost can be reduced. That is, after manufacturing a plurality of ink jet recording heads, it is not necessary to rank them based on the amount of displacement of the piezoelectric element 300, and there is no excess or deficiency of ink jet recording heads for each rank. It should be noted that the average etching amount of the test pattern 400 in the region to be each flow path forming substrate 10 of one flow path forming substrate wafer 110 may be the etching amount of the upper electrode film 80 in the entire flow path forming substrate wafer 110. Good.

  The etching amount of the upper electrode film 80 can be controlled by changing etching conditions such as etching time and output. In particular, the etching amount of the upper electrode film 80 can be easily and reliably controlled by adjusting the etching time.

  Incidentally, although it is conceivable that the test pattern is formed by a material different from that of the upper electrode film 80 of the piezoelectric element 300 and a different process, the test pattern is formed when the opening 201 is formed in the protective film 200. This is for measuring the etching amount obtained by over-etching, and is not preferable because an error occurs between the etching amount of the upper electrode film 80 and the etching amount of the test pattern. On the other hand, according to the present invention, the test pattern 400 is formed simultaneously with the upper electrode film 80 of the same layer as the upper electrode film 80 of the piezoelectric element 300, so that the upper electrode film 60 is over-etched with the test pattern 400. Can be measured with high accuracy. Further, as in the present embodiment, the test pattern 400 having the same configuration as that of the piezoelectric element 300 is formed at the same time as the piezoelectric element 300, whereby the film formation conditions of the piezoelectric element 300 and the film formation conditions of the test pattern 400 are made the same. The etching amount obtained by over-etching the upper electrode film 60 can be measured with higher accuracy.

  Next, as shown in FIG. 8A, a lead electrode 90 made of gold (Au) is formed over the entire surface of the flow path forming substrate wafer 110 and then patterned for each piezoelectric element 300.

  Next, as shown in FIG. 8B, the protective substrate wafer 130 is bonded onto the flow path forming substrate wafer 110 via an adhesive 35. Here, the protective substrate wafer 130 is formed by integrally forming a plurality of protective substrates 30, and a reservoir portion 31 and a piezoelectric element holding portion 32 are formed in advance on the protective substrate wafer 130. By bonding the protective substrate wafer 130, the rigidity of the flow path forming substrate wafer 110 is remarkably improved.

  Next, as shown in FIG. 8C, the flow path forming substrate wafer 110 is thinned to a predetermined thickness.

  Next, as shown in FIG. 9A, a mask 52 is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape. Then, as shown in FIG. 9B, the flow path forming substrate wafer 110 is anisotropically etched (wet etching) using an alkaline solution such as KOH through a mask 52, thereby corresponding to the piezoelectric element 300. The pressure generating chamber 12, the communication part 13, the ink supply path 14, the communication path 15 and the like are formed.

  Thereafter, the mask 52 on the surface of the flow path forming substrate wafer 110 is removed, and unnecessary portions of the outer peripheral edge portions of the flow path forming substrate wafer 110 and the protective substrate wafer 130 are removed by cutting, for example, by dicing. To do. The nozzle plate 20 having the nozzle openings 21 formed on the surface of the flow path forming substrate wafer 110 opposite to the protective substrate wafer 130 is bonded, and the compliance substrate 40 is bonded to the protective substrate wafer 130. By dividing the flow path forming substrate wafer 110 and the like into the flow path forming substrate 10 and the like of one chip size as shown in FIG. 1, the ink jet recording head of this embodiment is obtained.

  In the present embodiment, the electrical resistance value is measured by bringing the probe into direct contact with the end portion of each upper electrode film 80 of the test pattern 400, but the present invention is not limited to this. Here, another example is shown in FIG. FIG. 10 is an enlarged plan view of a main part of the flow path forming substrate wafer, a CC ′ sectional view, and a DD ′ sectional view.

  As shown in FIG. 10, when forming the lead electrode 90 that is a lead-out wiring drawn out from the piezoelectric element 300, a test lead-out wiring 91 that is drawn out from each end portion of each upper electrode film 80 of the test pattern 400 is formed. To do. A probe is brought into contact with the test lead-out wiring 91 to measure the electric resistance value of each upper electrode film 80 of the test pattern 400. In this case, the measurement of the electric resistance value of each upper electrode film 80 of the test pattern 400 is not particularly limited as long as the lead electrode 90 is formed. For example, the protective substrate wafer 130 is used as the flow path forming substrate wafer. It may be after bonding to 110 or after being divided into chips.

  After the lead electrode 90 and the test lead-out wiring 91 are formed in this way, the electrical resistance value of each upper electrode film 80 of the test pattern 400 is measured, so that scratches due to contact with the probe occur, and the subsequent steps It is possible to prevent the upper electrode film 80 from being peeled off and generating foreign matter (particularly in the step of forming the lead electrode 90). Further, since the upper electrode film 80 of the test pattern 400 is etched by reverse sputtering when the lead electrode 90 is formed by sputtering, the etching amount by the reverse sputtering 400 can also be measured. The final thickness of can be grasped.

(Embodiment 2)
FIG. 11 is an enlarged plan view of the main part of the flow path forming substrate wafer according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the member similar to Embodiment 1 mentioned above, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 11, the test pattern 400A is composed of a first test pattern 401A and a second test pattern 402A. The first test pattern 401A and the second test pattern 402A are provided with the same shape and the same size as the piezoelectric element 300, respectively.

  The protective film 200 of the test pattern 400A is provided with a terminal exposed portion 203A that exposes an end portion of each upper electrode film 80. Two terminal exposed portions 203A are provided at each end of each upper electrode film 80 of the test pattern 400A.

  The protective film 200 covering the second test pattern 402A is provided with an inspection opening 204A that exposes a part of the surface of the upper electrode film 80.

  As described above, the state in which only the terminal exposed portion 203A is provided in the first test pattern 401 is the first state, and the state in which the terminal exposed portion 203A and the inspection opening 204A are provided in the second test pattern 402A is the first state. 2 state.

  Then, by passing a current through both ends exposed by the two terminal exposed portions 203A on the outer side of the upper electrode film 80 of the first test pattern 401A, and measuring the potential difference between the two inner terminal exposed portions 203A, The electrical resistance value of the first test pattern 401A is measured. Further, the electrical resistance value of the upper electrode film 80 of the second test pattern 402A is also measured by the same method as the first test pattern 401A. Thereby, the etching amount of the upper electrode film 80 overetched when the inspection opening 204A is formed in the second test pattern 402A can be acquired.

  By measuring the electric resistance value using such a test pattern 400A, it is possible to obtain an etching amount in which the upper electrode film 80 of the piezoelectric element 300 is over-etched.

(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 first and second embodiments described above, the test patterns 400 and 400A including the piezoelectric layer 70 and the upper electrode film 80 are formed on the lower electrode film 60. However, the test pattern is formed on the piezoelectric element 300. What is necessary is just to have the upper electrode film | membrane 80 which consists of the same layer as the electrode film | membrane 80, and is electrically discontinuous with each electrode 60 and 80 of the piezoelectric element 300. FIG. That is, a test pattern composed only of the upper electrode film 80 in a region where the lower electrode film 60 of the flow path forming substrate wafer 110 is not provided, or a test pattern composed only of the piezoelectric layer 70 and the upper electrode film 80. May be provided.

  In the first and second embodiments described above, the test patterns 400 and 400A having the cross shape or the same shape as the piezoelectric element 300 are used. However, the shape and size of the test pattern are not particularly limited thereto. Absent.

  Further, in the first and second embodiments described above, the test patterns 400 and 400A used at the time of manufacturing the head are left when the head is completed. However, the present invention is not limited to this, and the upper electrode film 80 is overlaid by the test patterns 400 and 400A. After measuring the etched etching amount, the test patterns 400 and 400A may be removed. That is, for example, the test patterns 400 and 400A are formed in unnecessary portions other than the region to be the chip of the flow path forming substrate wafer 110, and the test patterns 400 and 400A are simultaneously removed when the unnecessary portions are removed. Also good.

  In the first and second embodiments described above, the test patterns 400 and 400A are formed in the regions to be the flow path forming substrates 10 of the flow path forming substrate wafer 110. However, the present invention is not particularly limited thereto. One test pattern 400, 400A may be formed for a plurality of flow path forming substrates 10, and one test pattern 400, 400A is formed for each flow path forming substrate wafer 110. It may be.

  Furthermore, in the first and second embodiments described above, the test includes two test patterns 401 and 401A that are in the first state and second test patterns 402 and 402A that are in the second state. The patterns 400 and 400A are formed, and the electric resistance values of the first test patterns 401 and 401A and the second test patterns 402 and 402A are measured at the same time. The test pattern is formed, the state before the protective film is formed on the test pattern is set as the first state, the electrical resistance value of the upper electrode film of the test pattern in the first state is measured, and then the test pattern is inspected. The protective film 200 provided with the opening for forming is formed as the second state, and the electrical resistance value of the upper electrode film of the test pattern may be measured in the second state. . That is, the electrical resistance value may be measured both before the protective film is formed on one test pattern and after the protective film having the inspection opening is formed. In such a case, for example, the position where the probe for measuring the electric resistance value is brought into contact with the first state needs to be the same position in the first state and the second state. In addition, when the probe is brought into contact with the test pattern in the first state, the upper electrode film 60 is damaged, and in the process of forming the protective film 200 thereafter, the upper electrode film 60 is peeled off and foreign matter is generated. There is a fear. Further, when the protective film is formed on the test pattern in the first state and the test pattern is in the second state, the upper electrode film of the test pattern is etched by reverse sputtering when the protective film is formed by sputtering. The difference between the electrical resistance value in the first state and the electrical resistance value in the second state includes the etching amount of reverse sputtering in addition to the etching amount when the opening 201 is formed in the protective film 200. The measured value will be measured.

  In the first and second embodiments described above, a silicon single crystal substrate is exemplified as the flow path forming substrate 10, but the present invention is not particularly limited thereto, and the present invention is also effective for an SOI substrate, a glass substrate, an MgO substrate, and the like. It is. Further, the elastic film 50 made of silicon dioxide is provided in the lowermost layer of the diaphragm, but the structure of the diaphragm is not particularly limited to this.

  In the first and second embodiments described above, the ink jet recording head has been described as an example of the liquid ejecting head. However, the present invention is widely applied to all liquid ejecting heads and ejects liquids other than ink. Of course, the invention can also be applied to 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 (field emission 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.

  The present invention is not limited to a method for manufacturing an actuator device mounted on a liquid ejecting head typified by an ink jet recording head, and can also be applied to a method for manufacturing an actuator device mounted on another device.

FIG. 2 is an exploded perspective view illustrating a schematic configuration 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. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. 6 is a plan view illustrating the method for manufacturing the recording head according to Embodiment 1. FIG. 6A and 6B are a plan view and a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. 6 is a plan view illustrating the method for manufacturing the recording head according to Embodiment 1. FIG. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. 6A and 6B are a plan view and a cross-sectional view of a recording head showing another example of Embodiment 1. FIG. FIG. 6 is an enlarged plan view of a main part of a recording head according to a second embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Flow path formation board | substrate, 12 Pressure generation chamber, 13 Communication part, 14 Ink supply path, 15 Communication path, 20 Nozzle plate, 21 Nozzle opening, 30 Protection board, 31 Reservoir part, 32 Piezoelectric element holding part, 40 Compliance board, 60 lower electrode film, 70 piezoelectric layer, 80 upper electrode film, 90 lead electrode, 100 reservoir, 120 drive circuit, 121 connection wiring, 200 protective film, 201 opening, 202 connection hole, 203, 203A terminal exposed part, 204 , 204A inspection opening, 300 piezoelectric element, 400, 400A test pattern, 401, 401A first test pattern, 402, 402A second test pattern

Claims (10)

A region facing the upper electrode of the protective film after forming a piezoelectric element composed of a lower electrode, a piezoelectric layer and an upper electrode on one surface of the substrate, forming a protective film made of an insulating material covering the piezoelectric element Is an actuator device manufacturing method for forming an opening exposing the upper electrode by etching,
A test pattern that is electrically discontinuous with the electrode of the piezoelectric element and has the same layer as the upper electrode is formed on the substrate, and the test pattern is covered with the protective film that covers the piezoelectric element, and the protection Forming a test opening that exposes the upper electrode by simultaneously etching the region opposite to the upper electrode of the test pattern of the film;
In the first state in which the inspection opening is not formed in the test pattern, the electrical resistance value of the upper electrode of the test pattern is measured, and the protective film having the inspection opening in the test pattern In the formed second state, the electrical resistance value of the upper electrode of the test pattern is measured, and the opening is formed based on the electrical resistance value in the first state and the second electrical resistance value. A method for manufacturing an actuator device, comprising: obtaining an etching amount of the upper electrode when formed.   The second state is a state in which two or more terminal exposed portions exposing the upper electrode are formed outside the inspection opening of the protective film covering the test pattern, and the measurement of the electric resistance value is performed. 2. The method of manufacturing an actuator device according to claim 1, wherein the terminal exposed portion is performed.   3. The method for manufacturing an actuator device according to claim 1, wherein the test pattern is formed of the same layer as the lower electrode, the piezoelectric layer, and the upper electrode.   The method for manufacturing an actuator device according to any one of claims 1 to 3, wherein the electric resistance value of the test pattern is measured by a four-terminal method.   5. The method for manufacturing an actuator device according to claim 1, wherein the first state is a state before forming the protective film covering the piezoelectric element and the test pattern. 6. .   Two test patterns are formed, and the first state is a state in which the protective film in which the inspection opening is not provided in one test pattern, and the second state is: 5. The method of manufacturing an actuator device according to claim 1, wherein the protective film provided with the inspection opening is formed on the other test pattern. 6.   As the test pattern, the upper electrode is formed in a cross shape, and as the first state, one test pattern is covered with the protective film, and a terminal exposed portion exposing the four end portions of the test pattern is formed. In the second state, the second test state is covered with the protective film, and the terminal exposed portion exposing the four end portions of the test pattern and the cross-shaped crossing region are exposed. An electrical resistance value is obtained by passing a current through a pair of adjacent ends exposed by the terminal exposed portions of the two test patterns and measuring a potential difference between the other ends in a state where an opening is formed. The method of manufacturing an actuator device according to claim 6, wherein:   A lead-out wiring led out from the piezoelectric element is formed, and the upper electrode exposed by the terminal exposed portion of the test pattern is made of the same layer as the lead-out wiring and is electrically discontinuous with the lead-out wiring. 8. The electrical resistance value in the first state and the second state of the test pattern is formed through the test lead wire after the test lead wire is formed. A manufacturing method of the actuator device described.   The actuator device according to any one of claims 1 to 8, wherein the etching amount of the opening is controlled by feeding back the etching amount acquired in the step of acquiring the etching amount of the upper electrode. Manufacturing method.   The manufacturing method according to claim 1, wherein the actuator device is formed on one surface of a flow path forming substrate provided with a pressure generating chamber communicating with a nozzle opening for ejecting liquid. A manufacturing method of a liquid jet head characterized by the above.

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