JP2006144090A - Sputtering method, sputtering apparatus, piezoelectric element manufacturing method, and liquid spray head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sputtering method, a sputtering apparatus, a piezoelectric element manufacturing method, and a liquid spray head having a piezoelectric element capable of depositing an excellent thin film of the uniform film thickness on a substrate. <P>SOLUTION: When depositing a thin film by sputtering a target 402 on a surface of a substrate 110 arranged facing the target 402, the spacing (TS) between the surface of the target 402 and the surface of the substrate 110 is set to be ≥100 mm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sputtering method for forming a thin film made of a metal material or the like on a substrate, a sputtering apparatus, a method for manufacturing a piezoelectric element using the sputtering method, and a liquid ejecting head including the piezoelectric element.

  A piezoelectric element used for a liquid ejecting head or the like includes, for example, a piezoelectric layer made of crystallized piezoelectric ceramics and exhibiting an electromechanical conversion function, and a plurality of electrodes sandwiching the piezoelectric layer.

  In addition, as a liquid ejecting head using such a piezoelectric element, for example, a part of a pressure generation chamber communicating with a nozzle opening for ejecting ink droplets is configured by a diaphragm, and the diaphragm is deformed by the piezoelectric element. There is an ink jet recording head that pressurizes ink in a pressure generating chamber and ejects ink droplets from nozzle openings. Two types of ink jet recording heads have been put into practical use: those using a longitudinal vibration mode piezoelectric actuator that extends and contracts in the axial direction of the piezoelectric element, and those using a flexural vibration mode piezoelectric actuator. As an actuator using a flexural vibration mode actuator, for example, a lower electrode, a piezoelectric layer, and an upper electrode are sequentially laminated on a vibration plate by a film forming technique, and each of these layers corresponds to a pressure generation chamber by a lithography method. It is known that an independent piezoelectric element is formed for each pressure generation chamber by dividing the shape into a shape to be formed (see, for example, Patent Document 1).

  For example, when a thin film such as a lower electrode constituting such a piezoelectric element is formed, a sputtering method is generally used. Here, the thin film can be formed relatively easily by using the sputtering method. However, it is difficult to control the film thickness, film quality, and the like with high accuracy. For example, the film thickness and the like may vary even in the same substrate.

  The displacement characteristics of the piezoelectric element are largely determined by the crystallinity of the piezoelectric layer formed on the lower electrode, for example, the crystal grain size, crystal orientation, and the like. For example, as described in Patent Document 1, the crystallinity of the piezoelectric layer can be controlled to some extent by the film thickness of the titanium layer formed on the lower electrode (lower electrode). However, it is difficult for the crystallinity of the piezoelectric layer to sufficiently control the crystallinity of the piezoelectric layer only by the thickness of the titanium layer.

JP 2001-88294 A (FIG. 11, claims, etc.)

  The present invention has been made in view of such circumstances, and includes a sputtering method, a sputtering apparatus, a method for manufacturing a piezoelectric element, and a piezoelectric element that can form a thin film on a substrate in a favorable and uniform thickness. It is an object of the present invention to provide a liquid ejecting head.

The first aspect of the present invention for solving the above problem is that when a thin film is formed by sputtering the target on the surface of the substrate disposed facing the target, the surface of the target, the surface of the substrate, The sputtering method is characterized in that the distance between the layers is 100 mm or more.
In the first aspect, the thin film can be formed with a substantially uniform thickness over the in-plane direction of the substrate, and the film quality can be improved.

According to a second aspect of the present invention, there is provided the sputtering method according to the first aspect, wherein a film forming rate of the thin film is 1 nm / sec or less.
In the second aspect, the film thickness, film quality, and the like can be made more uniform by relatively reducing the film formation rate.

According to a third aspect of the present invention, there is provided the sputtering method according to the first or second aspect, wherein the substrate is arranged at a position eccentric with respect to a center of the target.
In the third aspect, the film thickness, film quality, etc. of the thin film can be further uniformed.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the thin film is formed on the surface of the substrate by magnetron sputtering.
In the fourth aspect, a thin film having a uniform film thickness and film quality can be formed relatively easily.

According to a fifth aspect of the present invention, there is provided a step of forming the thin film as the lower electrode film on the one surface side of the substrate using the sputtering method according to any one of the first to fourth aspects; A method of manufacturing a piezoelectric element, comprising: a step of forming a piezoelectric layer; and a step of forming an upper electrode film on the piezoelectric layer.
In the fifth aspect, the crystallinity of the piezoelectric layer formed on the lower electrode film can be improved by forming the lower electrode film with a uniform film thickness and film quality.

According to a sixth aspect of the present invention, in the fifth aspect, the method further includes a step of forming a seed titanium layer made of titanium (Ti) on the lower electrode film before the step of forming the piezoelectric layer. A method of manufacturing a piezoelectric element is provided.
In the fifth aspect, a piezoelectric layer having more excellent crystallinity can be formed by controlling the film thickness of the seed titanium layer.

According to a seventh aspect of the present invention, in the fifth or sixth aspect, the step of forming the piezoelectric layer comprises applying a ferroelectric material on the lower electrode film to form a ferroelectric precursor film. A step of drying the ferroelectric precursor film, a degreasing step of degreasing the ferroelectric precursor film, and a firing step of firing the ferroelectric precursor film to form a ferroelectric film And a method of manufacturing the piezoelectric element.
In the seventh aspect, a piezoelectric layer having excellent crystallinity such as crystal orientation and crystal grain size can be formed.

According to an eighth aspect of the present invention, there is provided a liquid ejecting head including the piezoelectric element manufactured by the manufacturing method according to any one of the fifth to seventh aspects.
According to the eighth aspect, it is possible to realize a liquid ejecting head capable of improving the displacement characteristics of the piezoelectric element and ejecting liquid droplets satisfactorily.

A ninth aspect of the present invention includes a cathode to which a target is attached, and a holding member that holds a substrate disposed so as to face the target. The target and the holding member are surfaces of the target. And a surface of the substrate held by the holding member are arranged so as to be at least 100 mm.
In the ninth aspect, the thin film can be formed with a substantially uniform thickness over the in-plane direction of the substrate, and the film quality can be improved.

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

  A plurality of pressure generating chambers 12 are arranged in parallel in the width direction of the flow path forming substrate 10. Further, a communication portion 13 is formed in a region outside the longitudinal direction of the pressure generation chamber 12 of the flow path forming substrate 10, and the communication portion 13 and each pressure generation chamber 12 are provided for each pressure generation chamber 12. Communication is made via a path 14. The communication unit 13 constitutes a part of the reservoir 100 that communicates with a reservoir unit 32 of the protective substrate 30 described later and serves as a common ink chamber for the pressure generation chambers 12. The ink supply path 14 is formed with a narrower width than the pressure generation chamber 12, and maintains a constant flow path resistance of ink flowing into the pressure generation chamber 12 from the communication portion 13.

On the surface side of the flow path forming substrate 10 on which the protective film 15 is formed, a nozzle plate 20 in which 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 formed. However, it is fixed by an adhesive or a heat welding film. The nozzle plate 20 has a thickness of, for example, 0.01 to 1 mm, a linear expansion coefficient of 300 ° C. or less, for example, 2.5 to 4.5 [× 10 ⁻⁶ / ° C.], glass ceramics, silicon It consists of a single crystal substrate or stainless steel.

  On the other hand, as described above, the elastic film 50 having a thickness of, for example, about 1.0 μm is formed on the surface of the flow path forming substrate 10 opposite to the nozzle plate 20, and the elastic film 50 is formed on the elastic film 50. An insulator film 55 having a thickness of, for example, about 0.4 μm is formed. Further, on the insulator film 55, a lower electrode film 60 having a thickness of, for example, about 0.2 μm, a piezoelectric layer 70 having a thickness of, for example, about 1.0 μm, and a thickness of, for example, about 0 The upper electrode film 80 having a thickness of 0.05 μm is laminated by a process described later to constitute the piezoelectric element 300. Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80. In general, one electrode of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure generating chamber 12. In 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 this embodiment, the lower electrode film 60 is a common electrode of the piezoelectric element 300, and the upper electrode film 80 is an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for the convenience of the drive circuit and wiring. In either case, a piezoelectric active part is formed for each pressure generating chamber. Further, here, the piezoelectric element 300 and the vibration plate that is displaced by driving the piezoelectric element 300 are collectively referred to as a piezoelectric actuator.

  Further, a lead electrode 90 is connected to the upper electrode film 80 of each piezoelectric element 300, and a voltage is selectively applied to each piezoelectric element 300 via the lead electrode 90. .

  Further, a protective substrate 30 having a piezoelectric element holding portion 31 is bonded to a surface facing the piezoelectric element 300 on the surface of the flow path forming substrate 10 on the piezoelectric element 300 side. Since the piezoelectric element 300 is formed in the piezoelectric element holding part 31, it is protected in a state hardly affected by the external environment. Further, the protective substrate 30 is provided with a reservoir portion 32 in a region corresponding to the communication portion 13 of the flow path forming substrate 10. In this embodiment, the reservoir portion 32 is provided along the direction in which the pressure generating chambers 12 are arranged so as to penetrate the protective substrate 30 in the thickness direction, and as described above, the communication portion of the flow path forming substrate 10. The reservoir 100 is connected to the pressure generation chamber 12 and serves as a common ink chamber for the pressure generation chambers 12. A through hole 33 penetrating the protective substrate 30 in the thickness direction is provided in a region between the piezoelectric element holding portion 31 and the reservoir portion 32 of the protective substrate 30, and one of the lower electrode films 60 is provided in the through hole 33. And the tip of the lead electrode 90 are exposed, and one end of a connection wiring extending from the driving IC is connected to the lower electrode film 60 and the lead electrode 90, although not shown.

  In addition, examples of the material of the protective substrate 30 include glass, ceramic material, metal, resin, and the like, but it is more preferable that the material is substantially the same as the coefficient of thermal expansion of the flow path forming substrate 10. In this embodiment, the silicon single crystal substrate made of the same material as the flow path forming substrate 10 is used.

  Further, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded onto a region corresponding to the reservoir portion 32 of the protective substrate 30. The sealing film 41 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μm). Yes. The fixing plate 42 is made of a hard material such as metal (for example, stainless steel (SUS) having a thickness of 30 μm). Since the region of the fixing plate 42 facing the reservoir 100 is an opening 43 that is completely removed in the thickness direction, one surface of the reservoir 100 is sealed only with a flexible sealing film 41. Has been.

  In 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 subjected to pressure according to a recording signal from the driving IC 210. By applying a voltage between each of the lower electrode film 60 and the upper electrode film 80 corresponding to the generation chamber 12 to bend and deform the piezoelectric element 300 and the diaphragm, the pressure in each pressure generation chamber 12 is increased. Ink is ejected from the opening 21.

  Hereinafter, a method for manufacturing such an ink jet recording head, in particular, a method for manufacturing a piezoelectric element will be described with reference to FIGS. 3-6 is a figure which shows the cross section of the longitudinal direction of a pressure generation chamber, and FIG. 7 is a figure which shows the outline of a sputtering device.

  First, as shown in FIG. 3A, a channel forming substrate wafer 110 which is a silicon wafer is thermally oxidized in a diffusion furnace at about 1100 ° C., and a silicon dioxide film 51 constituting an elastic film 50 is formed on the surface thereof. To do. In the present embodiment, a silicon wafer having a relatively thick and high rigidity of about 625 μm is used as the flow path forming substrate wafer 110.

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, after a zirconium (Zr) layer is formed on the elastic film 50 (silicon dioxide film 51) by, for example, a sputtering method, the zirconium layer is thermally oxidized in a diffusion furnace at 500 to 1200 ° C., for example. Thus, the insulator film 55 made of zirconium oxide (ZrO ₂ ) is formed.

  Next, as shown in FIG. 3C, the lower electrode film 60 which is a thin film is formed on the insulator film 55 by stacking, for example, platinum and iridium by sputtering.

  Here, in the present invention, when the lower electrode film 60 is formed by sputtering, the distance between the surface of the target of the sputtering apparatus and the surface of the flow path forming substrate wafer 110 (insulator film 55) is set to 100 mm or more. . For example, the sputtering apparatus according to the present embodiment is a magnetron type sputtering apparatus, and is opposed to the target 402 and a magnetron cathode 403 that is connected to a DC power source 401 and to which the target 402 is fixed, as shown in FIG. And a holding member 404 that holds the flow path forming substrate wafer 110. The magnetron cathode 403 and the holding member 404 are arranged in a vacuum chamber (not shown).

  In the present invention, the target 402 and the holding member 404 are arranged such that the distance TS between the surface of the flow path forming substrate wafer 110 and the surface of the target 402 is 100 mm or more. The surface of the flow path forming substrate wafer 110, that is, the insulator film is thus sputtered in a state where the distance TS between the surface of the flow path forming substrate wafer 110 and the surface of the target 402 is 100 mm or more. A lower electrode film 60 is formed on 55. Further, it is preferable that the deposition rate when forming the lower electrode film 60 in this way is 1 nm / sec or less. Furthermore, it is preferable to rotate the substrate at about 30 rpm in order to make the distribution of the film thickness in the substrate surface uniform.

  Thereby, the lower electrode film 60 having a uniform thickness can be formed, and the film quality can be improved. Furthermore, the film thickness uniformity, film quality, and the like of the lower electrode film 60 are improved in this way, and as will be described in detail later, the film quality of the piezoelectric layer 70 formed on the lower electrode film 60, for example, crystal The particle size and crystal orientation can be well controlled.

  In the present embodiment, the target 402 is provided at a position deviated from the center of the flow path forming substrate wafer 110, whereby the thickness of the lower electrode film 60 and the like can be made more uniform. Of course, the target 402 may be provided at a position that coincides with the center of the flow path forming substrate wafer 110.

  Next, as shown in FIG. 3D, titanium (Ti) is applied on the lower electrode film 60 by, for example, a sputtering method to form a seed titanium layer 65 having a predetermined thickness. The seed titanium layer 65 is preferably laminated continuously on the lower electrode 60. The seed titanium layer 65 serves as a crystal nucleus of the piezoelectric layer 70 formed in a process described later. The crystal grain size and crystal orientation of the piezoelectric layer 70 are determined by the thickness of the seed titanium layer 65. It depends on. The crystal grain size of the piezoelectric layer 70 is desirably relatively small, for example, 200 nm or less. In order to obtain the piezoelectric layer 70 having such a crystal grain size, it is necessary to form the seed titanium layer 65 with a thickness of about 2 nm or more.

Next, on the seed titanium layer 65 thus formed, for example, lead zirconate titanate (PZ
A piezoelectric layer 70 made of T) is formed. Here, in the present embodiment, a so-called sol-gel is obtained in which a so-called sol in which a metal organic material is dissolved and dispersed in a catalyst is applied, dried, gelled, and further fired at a high temperature to obtain a piezoelectric layer 70 made of a metal oxide. The piezoelectric layer 70 is formed using the method.

The manufacturing method of the piezoelectric layer 70 is not limited to the sol-gel method, and for example, a MOD (Metal-Organic Decomposition) method or the like may be used. Further, as the material of the piezoelectric layer 70, for example, a ferroelectric piezoelectric material such as lead zirconate titanate (PZT) or a relaxor strong material in which a metal such as niobium, nickel, magnesium, bismuth or yttrium is added thereto. A dielectric or the like is used. The composition may be appropriately selected in consideration of the characteristics, use, etc. of the piezoelectric element 300. For example, PbTiO ₃ (PT), PbZrO ₃ (PZ), Pb (Zr _x Ti _1-x ) O ₃ (PZT) ), Pb (Mg _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ (PMN-PT), Pb (Zn _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ (PZN-PT), Pb (Ni ₁ ) _{/ 3 Nb 2/3) O 3 -PbTiO} 3 (PNN-PT), Pb (In 1/2 Nb 1/2) O 3 -PbTiO 3 (PIN-PT), Pb (Sc 1/2 Ta 1/2 _{) O 3 -PbTiO 3 (PST-} PT), Pb (Sc 1/2 Nb 1/2) O 3 -PbTiO 3 (PSN-PT), BiScO 3 -PbTiO 3 (BS-PT), BiYbO 3 -PbTiO 3 (BY PT), and the like.

  As a specific forming procedure of the piezoelectric layer 70, first, as shown in FIG. 4A, a piezoelectric precursor film 71 which is a PZT precursor film is formed on the seed titanium layer 65. That is, a sol (solution) containing a metal organic compound is applied onto the flow path forming substrate wafer 110. Next, the piezoelectric precursor film 71 is heated to a predetermined temperature and dried for a predetermined time, and the sol solvent is evaporated to dry the piezoelectric precursor film 71. Further, the piezoelectric precursor film 71 is degreased at a constant temperature for a predetermined time in an air atmosphere. In addition, degreasing said here is removing the organic component of a sol film | membrane.

  Then, by repeating such coating, drying, and degreasing processes a predetermined number of times, for example, twice in the present embodiment, the piezoelectric precursor film 71 has a predetermined thickness as shown in FIG. Then, the piezoelectric precursor film 71 is crystallized by heat treatment in a diffusion furnace to form the piezoelectric film 72. That is, by firing the piezoelectric precursor film 71, crystals grow with the seed titanium layer 65 as a nucleus to form the piezoelectric film 72. For example, in this embodiment, the piezoelectric precursor film 71 is baked by heating at about 700 ° C. for 30 minutes to form the piezoelectric film 72. The crystal of the piezoelectric film 72 thus formed is preferentially oriented in the (100) plane. Further, after the piezoelectric film 72 is formed on the lower electrode film 60 in this way, the piezoelectric film 72 and the lower electrode film 60 are patterned into a predetermined shape. In this embodiment, after the piezoelectric film 72 formed of the two layers of the piezoelectric precursor film 71 is formed, the piezoelectric film 72 and the lower electrode film 60 are patterned into a predetermined shape. A piezoelectric film made of the piezoelectric precursor film may be formed, and the piezoelectric film and the lower electrode film may be patterned.

  Next, as shown in FIG. 4C, the seed titanium layer 65A is formed again on the patterned piezoelectric film 72 and the insulator film 55, and then the above-described coating, drying, degreasing, and firing steps are performed. By repeating a plurality of times, as shown in FIG. 4D, a piezoelectric layer 70 having a predetermined thickness composed of a plurality of layers, in this embodiment, five layers of piezoelectric films 72 is formed. For example, when the film thickness per sol application is about 0.1 μm, the entire film thickness of the piezoelectric layer 70 is about 1 μm.

  In the present invention, as described above, the lower electrode film 60 is formed by sputtering in a state where the distance (TS) between the flow path forming substrate wafer 110 and the target 402 is 100 mm or more. By controlling the film thickness of the seed titanium layer formed on the electrode film 60, the piezoelectric layer 70 having good crystallinity, that is, the crystal grain size is relatively small and the crystals are well oriented in the (100) plane. Can be formed.

(Test example)
Here, the lower electrode film is formed by changing the distance (TS) between the surface of the flow path forming substrate wafer and the surface of the target as shown in Table 1 below, and seed titanium having different thicknesses is formed on the lower electrode film. A plurality of samples of Examples 1 and 2 and Comparative Example in which the piezoelectric layer was formed under a certain condition via the layer were prepared. The deposition rate of the lower electrode film is about 0.1 to 0.2 nm / sec for the samples of Example 1 and Example 2, and about 2 to 3 nm / sec for the sample of the example. Met.

  And about the sample of each of these Examples 1 and 2 and a comparative example, the relationship between the thickness of a seed titanium layer, the (100) intensity | strength of a piezoelectric material layer, and the (100) orientation degree was investigated. The result is shown in FIG. The “orientation degree” here refers to the ratio of the diffraction intensity generated when the piezoelectric layer is measured by the X-ray diffraction wide angle method. Specifically, when the piezoelectric layer is measured by the X-ray diffraction wide angle method, peaks of diffraction intensity corresponding to a plurality of crystal planes including the (100) plane are generated. The “(100) orientation degree” means the ratio of the peak intensity corresponding to the (100) plane to the sum of the peak intensity corresponding to each of these planes.

  As shown in FIG. 8, both the samples of Examples 1 and 2 in which the lower electrode film was formed with the distance (TS) between the flow path forming substrate wafer and the target being 100 mm or more were (100) strength of the piezoelectric layer. And the peak of the (100) orientation degree was generated at a position where the thickness of the seed titanium layer was approximately 4 to 5 nm. Further, the peak value of the (100) strength of the piezoelectric layer showed a sufficiently high value although there was a slight difference between the sample of Example 1 and the sample of Example 2. Moreover, the peak value of the (100) orientation degree of the piezoelectric layer showed an extremely high value of 85 to 90% in both the samples of Examples 1 and 2. That is, in Examples 1 and 2, it was found that by controlling the film thickness of the seed titanium layer, a piezoelectric layer in which crystals are well oriented and the crystal grain size is extremely small can be obtained.

  On the other hand, in the sample of the comparative example in which the lower electrode film was formed with the interval (TS) between the flow path forming substrate wafer and the target being 100 mm or less, the peak values of the (100) strength and (100) orientation strength of the piezoelectric layer. Was equal to or greater than the samples of Examples 1 and 2. That is, even in the sample of the comparative example, the crystals of the piezoelectric layer can be favorably oriented by controlling the thickness of the seed titanium layer to be relatively thin. However, unlike the samples of Examples 1 and 2, the peaks of the (100) strength and (100) orientation strength of the piezoelectric layer occurred at positions where the thickness of the seed titanium layer was 1 nm or less. As described above, the crystal grain size of the piezoelectric layer is preferably as small as 200 nm or less. For this purpose, it is necessary to form a seed titanium layer with a thickness of 2 nm or more. That is, in the comparative example, by controlling the thickness of the seed titanium layer to be relatively thin, the crystal of the piezoelectric layer can be favorably oriented, but the crystal grain size at that time is significantly larger than 200 nm. I knew it would be.

  As is clear from these results, by forming the lower electrode film with a gap (TS) between the flow path forming substrate wafer and the target of 100 mm or more, the crystal of the piezoelectric layer formed thereon is excellent. And the crystal grain size can be made extremely small, 200 nm or less. That is, by forming the lower electrode film by the sputtering method of the present invention, a piezoelectric layer having excellent piezoelectric characteristics can be formed. When TS is small, it is considered that a high melting point material such as platinum or iridium is influenced by plasma in the vicinity of the target during film formation, and the action of the seed titanium layer on the crystallization of the piezoelectric layer is different.

  After the piezoelectric layer 70 is formed in this way, as shown in FIG. 5A, for example, an upper electrode film 80 made of iridium is formed on the entire surface of the flow path forming substrate wafer 110. Next, as shown in FIG. 5B, the piezoelectric layer 300 and the upper electrode film 80 are patterned in a region facing each pressure generating chamber 12 to form the piezoelectric element 300.

  Next, the lead electrode 90 is formed. Specifically, as shown in FIG. 5C, a metal layer 91 made of, for example, gold (Au) or the like is formed over the entire surface of the flow path forming substrate wafer 110. Thereafter, for example, the lead electrode 90 is formed by patterning the metal layer 91 for each piezoelectric element 300 through a mask pattern (not shown) made of a resist or the like.

  Next, as shown in FIG. 5D, a protective substrate wafer 130 that is a silicon wafer and serves as a plurality of protective substrates 30 is bonded to the piezoelectric element 300 side of the flow path forming substrate wafer 110. Since the protective substrate wafer 130 has a thickness of, for example, about 400 μm, the rigidity of the flow path forming substrate wafer 110 is remarkably improved by bonding the protective substrate wafer 130.

  Next, as shown in FIG. 6A, after the flow path forming substrate wafer 110 is polished to a certain thickness, the flow path forming substrate wafer 110 is further etched by wet etching with fluorinated nitric acid or the like. Of thickness. For example, in this embodiment, the flow path forming substrate wafer 110 is etched so as to have a thickness of about 70 μm. Next, as shown in FIG. 6B, a mask film 52 made of, for example, silicon nitride (SiN) is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape. Then, the flow path forming substrate wafer 110 is anisotropically etched through the mask film 52, whereby, as shown in FIG. 13 and the ink supply path 14 are formed.

  After that, 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. 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 above, one embodiment of the present invention has been described by exemplifying a liquid ejecting head including a piezoelectric element, but the present invention is not limited to this. Of course, it goes without saying that the sputtering method and sputtering apparatus of the present invention can be applied not only to the production of piezoelectric elements but also to the production of all thin films.

FIG. 3 is an exploded perspective view of a recording head according to an embodiment of the invention. 2A and 2B are a plan view and a cross-sectional view of a recording head according to an embodiment of the invention. FIG. 6 is a cross-sectional view illustrating a manufacturing process of a recording head according to an embodiment of the invention. FIG. 6 is a cross-sectional view illustrating a manufacturing process of a recording head according to an embodiment of the invention. FIG. 6 is a cross-sectional view illustrating a manufacturing process of a recording head according to an embodiment of the invention. FIG. 6 is a cross-sectional view illustrating a manufacturing process of a recording head according to an embodiment of the invention. It is a figure showing the outline of the sputtering device concerning one embodiment of the present invention. It is a graph which shows the relationship between the thickness of a seed titanium layer, and the crystal orientation of a piezoelectric material layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Flow path formation board | substrate, 12 Pressure generation chamber, 20 Nozzle plate, 21 Nozzle opening, 30 Protection board, 31 Piezoelectric element holding | maintenance part, 32 Reservoir part, 40 Compliance board | substrate, 50 Elastic film, 55 Insulator film, 60 Lower electrode film , 70 piezoelectric layer, 80 upper electrode film, 90 lead electrode, 100 reservoir, 110 flow path forming substrate wafer, 130 protective substrate wafer, 300 piezoelectric element, 402 target, 404 holding member

Claims (9)

When the thin film is formed by sputtering the target on the surface of the substrate disposed facing the target, the distance between the surface of the target and the surface of the substrate is set to 100 mm or more. Sputtering method. 2. The sputtering method according to claim 1, wherein a deposition rate of the thin film is 1 nm / sec or less. The sputtering method according to claim 1, wherein the substrate is disposed at a position that is eccentric with respect to a center of the target. The sputtering method according to claim 1, wherein the thin film is formed on the surface of the substrate by magnetron sputtering. A step of forming the thin film as the lower electrode film on one surface side of the substrate using the sputtering method according to any one of claims 1 to 4, a step of forming a piezoelectric layer on the lower electrode film, And a step of forming an upper electrode film on the piezoelectric layer. 6. The method of manufacturing a piezoelectric element according to claim 5, further comprising a step of forming a seed titanium layer made of titanium (Ti) on the lower electrode film before the step of forming the piezoelectric layer. . 7. The method of forming a piezoelectric layer according to claim 5, wherein the step of forming the piezoelectric layer includes a step of applying a ferroelectric material on the lower electrode film to form a ferroelectric precursor film, and the ferroelectric precursor film. A piezoelectric element comprising: a drying step of drying the ferroelectric precursor film; a degreasing step of degreasing the ferroelectric precursor film; and a firing step of firing the ferroelectric precursor film to form a ferroelectric film. Manufacturing method. A liquid ejecting head comprising the piezoelectric element manufactured by the manufacturing method according to claim 5. A cathode to which a target is attached; and a holding member that holds a substrate disposed so as to face the target. The target and the holding member are held by the surface of the target and the holding member. A sputtering apparatus characterized by being arranged so that a distance from a surface of a substrate is 100 mm or more.

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