JP2016032084A - Wafer and method of manufacturing the same, piezoelectric element, droplet discharge head, and droplet discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a wafer which allows for creation of a uniform crystalline film of high quality.SOLUTION: A method of manufacturing a wafer has a step for forming an amorphous film on one side of a substrate, and a step for irradiating the other side of the substrate, i.e., the opposite side from the one side, with light and crystallizing a part of the amorphous film. In the step for crystallizing a part of the amorphous film, the light is irradiated so that the amorphous film formed in a predetermined area including the periphery on one side of the substrate is not crystallized but is left as it is, and the amorphous film formed in an area other than the predetermined area is crystallized and becoming a crystalline film.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a wafer, a manufacturing method thereof, a piezoelectric element, a droplet discharge head, and a droplet discharge apparatus.

  Conventionally, a process of heating a film formed on a substrate to a certain temperature or more for a certain period of time using an electric furnace, an RTA (Rapid Thermal Annealing) apparatus, or the like has been performed. In such heat treatment, not only the film but also the entire substrate is heated.

  However, when the entire substrate is heated, there are restrictions such as using a heat-resistant substrate. In addition, when other structures and elements are provided on the substrate, other members that do not require heat treatment (other structures and elements) are heated, and dimensional accuracy shifts due to thermal damage or thermal stress. May occur and the performance may be significantly reduced.

  Therefore, as a method of not heating the entire substrate, heat treatment by laser irradiation is performed in the manufacturing process of the oxide piezoelectric film (for example, PZT film). For example, it is exemplified that an amorphous PZT film formed by sputtering is crystallized by irradiating a KrF excimer pulse laser (for example, see Non-Patent Document 1). According to this method, there is a possibility that an influence on a member that does not require heat treatment can be avoided.

  However, in the process of manufacturing a wafer in which a crystalline film is formed on a substrate, a contaminated region with scratches and dirt on the outer peripheral portion of the substrate is likely to be formed by handling during the manufacturing process. When the contaminated area on the outer periphery of the substrate is irradiated with laser light, the laser beam is absorbed more than usual due to scratches and dirt, causing abnormally high heat in the contaminated area, and a uniform high quality crystalline material. In some cases, the production of the film was hindered.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a wafer manufacturing method and the like capable of producing a uniform high-quality crystalline film.

  The method for manufacturing the wafer includes a step of forming an amorphous film on one side of the substrate, a step of irradiating light from the other side opposite to the one side of the substrate, and crystallizing a part of the amorphous film. And in the step of crystallizing a part of the amorphous film, the amorphous film formed in a predetermined region including the outer peripheral portion on one side of the substrate remains without being crystallized, and other than the predetermined region. It is necessary to irradiate the light so that the amorphous film formed in the region is crystallized into a crystalline film.

  According to the disclosed technique, it is possible to provide a wafer manufacturing method or the like capable of producing a uniform high-quality crystalline film.

It is a figure which illustrates the structure of the wafer concerning a 1st embodiment. It is a figure which illustrates the manufacturing method of the wafer concerning a 1st embodiment. It is a figure explaining the contamination area | region formed in the back surface outer peripheral part of a wafer. It is a figure which illustrates the structure of the wafer concerning the modification of a 1st embodiment. It is a figure which illustrates the manufacturing method of the wafer which concerns on 2nd Embodiment. It is a figure which illustrates the manufacturing method of the wafer which concerns on 3rd Embodiment. It is sectional drawing which illustrates the piezoelectric element which concerns on 4th Embodiment. FIG. 10 is a cross-sectional view (part 1) illustrating a droplet discharge head according to a fifth embodiment; FIG. 10 is a cross-sectional view (part 2) illustrating a droplet discharge head according to a fifth embodiment; It is a perspective view which illustrates the inkjet recording device which concerns on 6th Embodiment. It is a side view which illustrates the mechanism part of the inkjet recording device which concerns on 6th Embodiment.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant description may be omitted.

<First Embodiment>
First, the structure of the wafer 1 will be described. 1A and 1B are diagrams illustrating the structure of a wafer according to the first embodiment. FIG. 1A is a plan view, and FIG. 1B is a cross section taken along the line AA in FIG. FIG. Referring to FIG. 1, a wafer 1 according to the first embodiment includes a silicon oxide film (SiO ₂ film) 11, a titanium oxide film (TiOx film) 12, and a platinum film (Pt film) on a silicon substrate 10. 13 and the composite oxide film 14 are sequentially stacked.

  The thickness of the silicon substrate 10 can be about 650 μm, for example. The thickness of the silicon oxide film 11 can be about 600 nm, for example. The thickness of the titanium oxide film 12 can be set to, for example, about 50 nm. The thickness of the platinum film 13 can be about 100 nm, for example. Although the thickness of the complex oxide film 14 can be determined arbitrarily, it can be, for example, about 30 nm to 2 μm.

The composite oxide film 14 is, for example, a film (PZT film) containing lead (Pb), titanium (Ti), and zirconium (Zr). PZT is a solid solution of lead zirconate (PbZrO ₃ ) and lead titanate (PbTiO ₃ ). For example, the ratio of lead zirconate (PbZrO ₃ ) to lead titanate (PbTiO ₃ ) is 53:47, and the chemical formula indicates Pb (Zr _0.53 , Ti _0.47 ) O ₃ , generally PZT ( 53/47) can be used. PZT is a ferroelectric material.

  Hereinafter, the case where the composite oxide film 14 is a PZT film will be described as an example (therefore, the composite oxide film 14 may be referred to as a PZT film 14).

  The PZT film 14 includes an amorphous PZT film 15 formed in a predetermined region including the outer peripheral portion on one side of the silicon substrate 10 and a PZT crystalline film 16 formed in a region other than the predetermined region. The technical significance of such a structure will be described later.

  It should be noted that the size (width) of the outer peripheral portion of the silicon substrate 10 can be appropriately determined according to the required specifications, but is preferably within a region within 5 mm from the outer edge of the silicon substrate 10. More preferably, the region is within 10 mm from the outer edge of the substrate 10. This is because such a region often becomes a contaminated region.

  Next, a method for manufacturing the wafer 1 will be described. FIG. 2 is a diagram illustrating a wafer manufacturing method according to the first embodiment. First, in the step shown in FIG. 2A, a silicon oxide film 11, a titanium oxide film 12, and a platinum film 13 are sequentially stacked on a silicon substrate 10, and an amorphous PZT film 15 is formed on the platinum film 13.

  Specifically, for example, the silicon oxide film 11 having a thickness of about 600 nm is formed on the surface of the silicon substrate 10 having a thickness of about 650 μm by a CVD (Chemical Vapor Deposition) method, a thermal oxidation method, or the like. Then, a titanium oxide film 12 having a thickness of about 50 nm is laminated on the silicon oxide film 11 by, for example, a sputtering method or a CVD method. Further, a platinum film 13 having a thickness of about 100 nm is laminated on the titanium oxide film 12 by, for example, a sputtering method or a CVD method. The platinum film 13 functions as a light absorption layer that absorbs laser light irradiated from the other side opposite to one side of the silicon substrate 10 and heats the heated layer formed on the platinum film 13. Have

  The amorphous PZT film 15 can be formed on one side of the platinum film 13 by using, for example, a sputtering method or a CSD (Chemical Solution Deposition) method. In the present embodiment, the amorphous PZT film 15 is directly formed on one side of the platinum film 13 that is a light absorption layer. The film thickness of the amorphous PZT film 15 can be about 45 nm, for example.

When forming the amorphous PZT film 15 by the CSD method, first, for example, lead acetate, a zirconium alkoxide compound, and a titanium alkoxide compound are used as starting materials, and dissolved in methoxyethanol as a common solvent to prepare a uniform solvent. This homogeneous solvent is referred to as a PZT precursor solution. The composite oxide solid content concentration of the PZT precursor solution can be set to 0.1 to 0.7 mol / liter, for example. The mixing amount of lead acetate, zirconium alkoxide compound, and titanium alkoxide compound can be appropriately selected by those skilled in the art according to the desired composition of PZT (ratio of PbZrO ₃ and PbTiO ₃ ). For example, the aforementioned PZT (53/47) can be used.

  Next, a PZT precursor solution is applied to one side of the platinum film 13 by, for example, a spin coating method to form a coating film. Then, the coating film is heat-treated for about 1 minute with a hot plate at about 120 ° C., for example, and then heat-treated with a hot plate at about 180 ° C. to 500 ° C. for about 1 to 10 minutes, whereby an amorphous PZT film is formed on one side of the platinum film 13. 15 is formed.

  Next, in the step shown in FIG. 2B, light is irradiated from the other side of the silicon substrate 10 (the side where the amorphous PZT film 15 is not formed), and a part of the amorphous PZT film 15 is crystallized. Specifically, the amorphous PZT film 15 formed in a predetermined region including the outer peripheral portion on one side of the silicon substrate 10 remains without being crystallized, and the amorphous PZT film 15 formed in a region other than the predetermined region is crystallized. Then, the laser beam 71x is irradiated so that the PZT crystalline film 16 is obtained.

  The laser beam 71x is irradiated from the other side of the silicon substrate 10 in a region excluding the outer peripheral portion of the silicon substrate 10, passes through the silicon substrate 10, the silicon oxide film 11, and the titanium oxide film 12, and reaches the other side of the platinum film 13. . As the laser beam 71x, for example, a continuous wave laser beam having a wavelength of about 1500 nm can be used. The spot shape of the laser beam 71x can be, for example, a substantially rectangular shape. In this case, the size of the substantially rectangular shape can be set to, for example, about 0.35 mm × 1 mm.

The platinum film 13 has a very large absorption coefficient in the vicinity of a wavelength of 1500 nm, which is approximately 7 × 10 ⁵ cm ⁻¹ . For example, in the platinum film 13 having a film thickness of 100 nm, the transmittance of light in the vicinity of a wavelength of 1500 nm is 1% or less. Accordingly, the platinum film 13 absorbs almost all of the light energy of the laser light 71x having a wavelength of about 1500 nm irradiated to the platinum film 13.

  The light energy of the laser beam 71x absorbed by the platinum film 13 changes to heat and heats the platinum film 13. The heat of the platinum film 13 is transmitted (diffused) to the amorphous PZT film 15 formed on one side of the platinum film 13, and the amorphous PZT film 15 is locally heated from the platinum film 13 side. The heated portion of the amorphous PZT film 15 is changed in film quality (crystallized) to become a PZT crystalline film 16.

In general, the crystallization temperature of an amorphous PZT film is about 600 ° C. to 850 ° C., which is considerably lower than the melting point of platinum (1768 ° C.). Therefore, the amorphous PZT film 15 can be locally heated and crystallized without damaging the platinum film 13 by controlling the energy density and irradiation time of the laser light 71x incident on the platinum film 13. The energy density of the laser beam 71x can be set to about 1 × 10 ² to 1 × 10 ⁶ W / cm ² , for example. The irradiation time of the laser beam 71x can be, for example, about 1 ms to 200 ms.

  Further, the platinum film 13 is irradiated with the laser beam 71 x while relatively moving the laser beam 71 x and the silicon substrate 10 in a region excluding the outer peripheral portion of the silicon substrate 10. For example, in the region excluding the outer peripheral portion of the silicon substrate 10, the amorphous PZT film 15 is sequentially crystallized from the region on the left front surface of the paper in the depth direction of the paper. Then, the same operation is sequentially performed on the right side of the page.

  As a result, the amorphous PZT film 15 formed in a predetermined region including the outer peripheral portion on one side of the silicon substrate 10 remains without being crystallized, and a region other than the predetermined region (a region within a dotted line in FIG. 1A, etc.) The amorphous PZT film 15 formed in (1) is crystallized to become a PZT crystalline film 16. That is, the PZT film 14 composed of the amorphous PZT film 15 and the PZT crystalline film 16 is produced.

  The PZT crystalline film 16 is crystallized so as to be preferentially oriented in any one of (100), (110), and (111). The PZT crystalline film 16 has different characteristics depending on the orientation, and has a different use. For example, a PZT crystalline film whose main orientation is the (100) direction has a high relative dielectric constant, and is therefore suitable for use in a DRAM (Dynamic Random Access Memory). In addition, a PZT crystalline film having a main orientation of (110) is excellent in ferroelectric characteristics and pyroelectric characteristics, and is therefore preferably used for sensors and actuators. In addition, a PZT crystalline film whose main orientation is the (111) direction is suitable for use in a piezoelectric element because of little deterioration in displacement. A PZT crystalline film whose main orientation is the (111) direction has a large remanent polarization, and is therefore suitable for use in FRAM (registered trademark) (Ferroelectric Random Access Memory).

  Here, the reason why the laser beam is not irradiated on the outer peripheral portion of the silicon substrate 10 will be described. When the silicon substrate 10 is handled in the steps shown in FIGS. 2A and 2B, generally, at least a part of the outer peripheral portion of the silicon substrate 10 is in contact with tweezers or a handling fork of the apparatus. become. And the crack 61 as shown, for example in FIG. 3 is easy to be formed in the outer peripheral part (back surface outer peripheral part) of the other side of the silicon substrate 10 of the contact part. In particular, when a multilayer film is formed, the number of scratches 61 may increase due to an increase in the number of times the silicon substrate 10 is handled.

  Further, a chipping 62 is generally present on the outer peripheral portion of the silicon substrate 10. Further, when the amorphous PZT film 15 is formed by the CSD method, when the film is applied by spin coating, the liquid stain 63 may adhere to the outer peripheral portion on the other side of the silicon substrate 10 due to the flow of the liquid.

  Such a contaminated region in which the scratch 61, the chipping 62, the liquid stain 63, and the like exist absorbs the laser light 71x near the wavelength 1500 nm that is transparent to the silicon substrate 10. Therefore, during the production of the PZT crystalline film 16 from the amorphous PZT film 15, if the laser beam 71x is irradiated to the contaminated region on the outer peripheral portion on the other side of the silicon substrate 10, the laser beam 71x is absorbed in the contaminated region, Generate more heat than expected in the contaminated area.

  The heat generated in the contaminated area diffuses to one side of the silicon substrate 10 and may cause cracks or film peeling in the PZT crystalline film 16 formed at a position corresponding to the contaminated area on one side of the silicon substrate 10. . Furthermore, there is a concern that the crack or peeling of the film extends from the outer peripheral portion on one side of the silicon substrate 10 to the central portion due to the crystal of the film and affects the PZT crystalline film 16 other than the outer peripheral portion.

  In order to avoid such a phenomenon, at least the outer peripheral portion of the silicon substrate 10 is not irradiated with the laser beam 71x in the step shown in FIG. By this method, the PZT crystalline film 16 is formed in the central portion of the silicon substrate 10, and the amorphous PZT film 15 remains in the outer peripheral portion not irradiated with the laser beam.

  Even if there is a contaminated region on the outer peripheral portion of the other side of the silicon substrate 10, the contaminated region is not irradiated with the laser beam 71x, so that abnormal heat is not generated in the contaminated region, and the central portion of the silicon substrate 10 is affected. Never give. As a result, a high quality PZT crystalline film 16 can be formed at the center of the silicon substrate 10.

  As described above, in the method of manufacturing the wafer 1 according to the first embodiment, the amorphous PZT film 15 is formed on one side of the silicon substrate 10, and light is irradiated from the other side of the silicon substrate 10. A part thereof is crystallized to form a PZT crystalline film 16. However, the light irradiation at the time of crystallization is that the amorphous PZT film 15 formed in a predetermined region including the outer peripheral portion on one side of the silicon substrate 10 remains without being crystallized, and is formed in a region other than the predetermined region. The amorphous PZT film 15 is crystallized to become a PZT crystalline film 16.

  As a result, even when a contaminated area is formed on the outer peripheral portion on the other side of the silicon substrate 10 due to handling during the manufacturing process of the wafer 1, the predetermined area including the contaminated area is not irradiated with laser light. It is possible to avoid the occurrence of abnormally high heat. As a result, the wafer 1 in which the uniform high quality PZT crystalline film 16 is formed on one side of the silicon substrate 10 can be manufactured.

  Further, according to the method of manufacturing the wafer 1 according to the first embodiment, the platinum film 13 as the light absorption layer is hardly affected by heat, and locally from the amorphous PZT film 15 as the heated layer. A PZT crystalline film 16 can be formed. Therefore, even when it is applied to a device having a structure or element other than the heated layer, other members (other structures or elements) that do not require heat treatment are not heated, so thermal damage and heat Deviations in dimensional accuracy due to stress are unlikely to occur, and device performance degradation can be avoided.

  Therefore, it is preferable to apply the manufacturing method of the wafer 1 according to the first embodiment to a sensor, an actuator, or the like which is a device having a structure or an element other than the layer to be heated. It is preferable to apply to.

  In the above description, the wafer having the single PZT film 14 has been described. However, when the multilayer PZT film 14 is formed, the process of forming the amorphous PZT film 15 and irradiating the laser light is repeated. A film having a thickness can be formed. Of course, in this case, the second and subsequent PZT films 14 are not directly formed on the platinum film 13 but are laminated on the PZT film 14 formed before the PZT film 14.

  In the above description, the planar shape of the predetermined region including the outer peripheral portion on one side of the silicon substrate 10 (planar shape of the PZT crystalline film 16) is one rectangle (or square) (FIG. 1A). Reference). However, the planar shape of the predetermined region including the outer peripheral portion on one side of the silicon substrate 10 (planar shape of the PZT crystalline film 16) is, for example, a plurality of rectangles (for example, strips) as shown in FIG. It is good also as an area | region. In the case shown in FIG. 4A, for example, the amorphous PZT film 15 may be partially crystallized by scanning in a region other than the outer peripheral portion of the silicon substrate 10.

  Further, the planar shape of the predetermined region including the outer peripheral portion on one side of the silicon substrate 10 (planar shape of the PZT crystalline film 16) may be, for example, a circle as shown in FIG. In the case shown in FIG. 4B, for example, the amorphous PZT film 15 may be crystallized by scanning in a spiral manner in a region excluding the outer peripheral portion of the silicon substrate 10.

  The planar shape of the predetermined region including the outer peripheral portion on one side of the silicon substrate 10 (planar shape of the PZT crystalline film 16) is shown in FIGS. 1 (a), 4 (a), and 4 (b). Other quadrangles, triangles, lines, etc. may be used. That is, the planar shape of the predetermined region including the outer peripheral portion on one side of the silicon substrate 10 (planar shape of the PZT crystalline film 16) is an arbitrary shape that can be formed by moving the laser light and the silicon substrate 10 relatively. It can be. The planar shape refers to a shape when the object is viewed from the normal direction of the surface of the silicon substrate 10 on which the silicon oxide film 11 is formed.

  In the above description, an example in which the PZT film 14 is formed on the platinum film 13 is shown. However, instead of the PZT film 14, for example, Pb, La, Ni, Cr, CoTi, Zr, Ba, Nb, Bi, An oxide film or a composite oxide film having at least one of Fe and Mn may be used.

  In the above description, the platinum film 13 is formed on the silicon substrate 10 as the light absorption layer. However, instead of the silicon substrate 10, a metal substrate such as SUS or Pt, Pb, Cu, Ni, W is used. When a metal substrate containing any metal is used, the metal substrate itself becomes a light absorbing layer. When such a metal substrate is used, the platinum film 13 is not formed on the metal substrate, but the metal substrate itself is used as a light absorption layer, and laser light is irradiated from the other side of the metal substrate. The PZT film 14 and the like can be directly formed on the substrate.

In the above description, the silicon substrate 10 is used as an example, but a compound substrate such as sapphire, SiC, GaAs, MgO, or SrTiO ₃ may be used instead of the silicon substrate 10.

  In the above description, the platinum film 13 is used as the light absorption layer. However, as the light absorption layer in place of the platinum film 13, another heat resistant film having a melting point of 1000 ° C. or more may be used. Examples of other heat resistant films include metal films containing any one of Ir, Pd, Rh, W, Fe, Ni, Ta, Cr, Zr, Ti, and Au. Further, a metal alloy film containing any one of the above-mentioned metal alloys, a laminated film in which a plurality of layers of the metal film or the metal alloy film are arbitrarily selected, and the like are listed.

  In the above description, the platinum film 13 as the light absorption layer is irradiated with the continuous wave laser beam 71x. However, instead of the continuous wave laser beam 71x, a pulsed laser beam may be irradiated.

<Second Embodiment>
In the second embodiment, an example in which the outer peripheral portion of the silicon substrate is irradiated with laser light that is weaker than that of the central portion will be described. In the second embodiment, description of the same components as those of the already described embodiments may be omitted.

  FIG. 5 is a diagram illustrating a wafer manufacturing method according to the second embodiment. First, similarly to the process shown in FIG. 2A of the first embodiment, a silicon oxide film 11, a titanium oxide film 12, and a platinum film 13 are sequentially laminated on a silicon substrate 10, and further on the platinum film 13. Then, an amorphous PZT film 15 is formed.

  In the process shown in FIG. 5, light is irradiated from the other side of the silicon substrate 10 to crystallize a part of the amorphous PZT film 15. However, in the present embodiment, light is also applied to the other side of the silicon substrate 10 corresponding to a predetermined region including the outer peripheral portion on one side of the silicon substrate 10.

  Specifically, the laser beam 71y having the first irradiation power is irradiated on the other side of the silicon substrate 10 corresponding to a predetermined region including the outer peripheral portion on one side of the silicon substrate 10. Then, the other side of the silicon substrate 10 corresponding to a region other than the predetermined region is irradiated with laser light 71x having a second irradiation power larger than the first irradiation power. Note that the laser light 71x and the laser light 71y may have the same wavelength (for example, near a wavelength of 1500 nm).

  The first irradiation power of the laser beam 71y is an irradiation power that does not crystallize the amorphous PZT film 15, and the second irradiation power of the laser beam 71x is an irradiation power that crystallizes the amorphous PZT film 15. The first irradiation power of the laser beam 71y can be, for example, about ½ of the second irradiation power of the laser beam 71x.

  The laser beams 71x and 71y are irradiated while relatively moving the laser beams 71x and 71y and the silicon substrate 10 as in the first embodiment.

  As a result, the amorphous PZT film 15 formed in the predetermined region including the outer peripheral portion on one side of the silicon substrate 10 remains without being crystallized, and the amorphous PZT film 15 formed in the region other than the predetermined region is crystallized. A PZT crystalline film 16 is formed. That is, the PZT film 14 composed of the amorphous PZT film 15 and the PZT crystalline film 16 is produced.

  The wafer 1 manufacturing method according to the second embodiment has the following effects in addition to the effects of the wafer 1 manufacturing method according to the first embodiment. That is, since the wafer can be preheated by irradiating the laser beam 71y on the outer peripheral portion of the silicon substrate 10, a more uniform large-area PZT crystalline film can be formed. Since the irradiation power of the laser beam 71y is low, even if the laser beam 71y is irradiated to a defect such as a scratch, the generated heat can be suppressed to a level that does not cause damage to the PZT film 14.

<Third Embodiment>
In the third embodiment, an example in which a light shielding mask is provided on the outer periphery of a silicon substrate will be described. Note that in the third embodiment, description of the same components as those of the already described embodiments may be omitted.

  FIG. 6 is a diagram illustrating a wafer manufacturing method according to the third embodiment. First, similarly to the process shown in FIG. 2A of the first embodiment, a silicon oxide film 11, a titanium oxide film 12, and a platinum film 13 are sequentially laminated on a silicon substrate 10, and further on the platinum film 13. Then, an amorphous PZT film 15 is formed.

  In the step shown in FIG. 6, light is irradiated from the other side of the silicon substrate 10 to crystallize a part of the amorphous PZT film 15. However, in the present embodiment, before the step of crystallizing a part of the amorphous PZT film 15, the laser beam is applied to the other side of the silicon substrate 10 corresponding to a predetermined region including the outer peripheral portion on one side of the silicon substrate 10. An object that shields light 71x is placed.

  Specifically, a light shielding mask 69 (made of metal, resin, etc.) is disposed on the other side of the silicon substrate 10 corresponding to a predetermined region including the outer peripheral portion on one side of the silicon substrate 10. Thereafter, similarly to the first embodiment, light is irradiated from the other side of the silicon substrate 10 to crystallize a part of the amorphous PZT film 15.

  Even when the other side of the silicon substrate 10 is irradiated with the laser beam 71x with a constant irradiation power, the laser beam 71x cannot reach the platinum film 13 in the region where the light shielding mask 69 is disposed on the other side of the silicon substrate 10. In other words, the platinum film 13 in this region is not heated. Note that the laser beam 71x is irradiated while relatively moving the laser beam 71x and the silicon substrate 10 as in the first embodiment.

  As a result, the amorphous PZT film 15 formed in the predetermined region including the outer peripheral portion on one side of the silicon substrate 10 remains without being crystallized, and the amorphous PZT film 15 formed in the region other than the predetermined region is crystallized. A PZT crystalline film 16 is formed. That is, the PZT film 14 composed of the amorphous PZT film 15 and the PZT crystalline film 16 is produced.

  The wafer 1 manufacturing method according to the third embodiment has the following effects in addition to the effects exhibited by the wafer 1 manufacturing method according to the first embodiment. That is, since the region where the amorphous PZT film 15 is crystallized can be determined by the presence or absence of a light shielding mask, the range in which the laser beam 71x having a constant irradiation power is scanned may be wider than that of the silicon substrate 10. As a result, the laser beam can be easily controlled.

  Note that the object that blocks light in the above description is not limited to an object that completely blocks light, but may be an object that partially blocks light (light can be partially transmitted). For example, an ND (Neutral density) filter that can partially transmit light may be used as an object that blocks light. In this case, if the transmittance of the object that shields light is set to about 50%, the predetermined region including the outer peripheral portion on one side of the silicon substrate 10 is heated to some extent, so that, similarly to the second embodiment, The effect of preheating the wafer can be expected.

<Fourth embodiment>
In the fourth embodiment, an example of a piezoelectric element using the wafer according to the first embodiment will be described. Note that in the fourth embodiment, descriptions of the same components as those of the above-described embodiments may be omitted.

  FIG. 7 is a cross-sectional view illustrating a piezoelectric element according to the fourth embodiment. Referring to FIG. 7, the piezoelectric element 2 includes a wafer 1 and a platinum film 17. However, in the wafer 1, the PZT film 14 is patterned to remove the amorphous PZT film 15, and only the PZT crystalline film 16 is formed. The thickness of the PZT crystalline film 16 can be set to about 1 μm, for example.

  A platinum film 17 which is a conductive film is formed in a predetermined region on the PZT crystalline film 16. The film thickness of the platinum film 17 can be about 100 nm, for example. The platinum film 17 can be formed by, for example, a sputtering method.

  In the piezoelectric element 2, the platinum film 13 functions as a lower electrode, the PZT crystalline film 16 functions as a piezoelectric film, and the platinum film 17 functions as an upper electrode. That is, when a voltage is applied between the platinum film 13 functioning as the lower electrode and the platinum film 17 functioning as the upper electrode, the PZT crystalline film 16 that is a piezoelectric film is mechanically displaced.

  Thus, by forming from the wafer 1 according to the first embodiment, the piezoelectric element 2 having the uniform high-quality PZT crystalline film 16 can be obtained. Further, since the PZT crystalline film 16 can be formed by local heating, the piezoelectric element 2 that can be easily integrated with other elements and has good stability can be obtained.

<Fifth embodiment>
In the fifth embodiment, an example of a droplet discharge head including the piezoelectric element according to the fourth embodiment is shown. Note that in the fifth embodiment, description of the same components as those of the above-described embodiments may be omitted.

  FIG. 8 is a cross-sectional view illustrating a droplet discharge head according to the fifth embodiment. Referring to FIG. 8, the droplet discharge head 3 includes the piezoelectric element 2 and a nozzle plate 40. On the nozzle plate 40, nozzles 41 for discharging ink droplets are formed. The nozzle plate 40 can be formed by, for example, Ni electroforming.

  A pressure chamber 10x (referred to as an ink flow path, a pressurized liquid chamber, a pressurized chamber, a discharge chamber, a liquid chamber, etc.) communicating with the nozzle 41 by the nozzle plate 40, the silicon substrate 10, and the silicon oxide film 11 serving as a vibration plate. May be formed). The silicon oxide film 11 serving as a vibration plate forms part of the wall surface of the ink flow path. In other words, the pressure chamber 10x is formed by communicating with the nozzle 41, and is defined by the silicon substrate 10 (which constitutes the side surface), the nozzle plate 40 (which constitutes the lower surface), and the silicon oxide film 11 (which constitutes the upper surface).

  The pressure chamber 10x can be produced, for example, by processing the silicon substrate 10 using etching. As the etching in this case, it is preferable to use anisotropic etching. Anisotropic etching utilizes the property that the etching rate differs with respect to the plane orientation of the crystal structure. For example, in anisotropic etching immersed in an alkaline solution such as KOH, the (111) plane has an etching rate of about 1/400 compared to the (100) plane. Thereafter, the nozzle plate 40 having the nozzles 41 is bonded to the lower surface of the silicon substrate 10. In FIG. 8, descriptions of the droplet supply means, the flow path, the fluid resistance, etc. are omitted.

The piezoelectric element 2 has a function of pressurizing ink in the pressure chamber 10x. The titanium oxide film 12 has a function of improving the adhesion between the platinum film 13 serving as a lower electrode and the silicon oxide film 11 serving as a vibration plate. Instead of the titanium oxide film 12, for example, a film made of Ti, TiN, Ta, Ta ₂ O ₅ , Ta ₃ N ₅ or the like may be used. However, the titanium oxide film 12 is not an essential component of the piezoelectric element 2.

  In the piezoelectric element 2, when a voltage is applied between the platinum film 13 serving as the lower electrode and the platinum film 17 serving as the upper electrode, the PZT crystalline film 16 serving as the piezoelectric film is mechanically displaced. Along with the mechanical displacement of the PZT crystalline film 16, the silicon oxide film 11 serving as a vibration plate is deformed and displaced in the lateral direction (d31 direction), for example, and pressurizes the ink in the pressure chamber 10x. Thereby, ink droplets can be ejected from the nozzle 41.

  As shown in FIG. 9, a plurality of droplet discharge heads 3 can be arranged in parallel to form the droplet discharge head 4.

<Sixth embodiment>
In the sixth embodiment, an ink jet recording apparatus is illustrated as an example of a liquid droplet ejection apparatus provided with a liquid droplet ejection head 4 (see FIG. 9). Note that in the sixth embodiment, descriptions of the same components as in the already described embodiments may be omitted.

  FIG. 10 is a perspective view illustrating an ink jet recording apparatus. FIG. 11 is a side view illustrating the mechanism unit of the ink jet recording apparatus.

  Referring to FIGS. 10 and 11, the ink jet recording apparatus 5 is an ink jet which is an embodiment of a droplet discharge head 4 mounted on a carriage 93 movable in the main scanning direction inside a recording apparatus main body 81. The recording head 94 is accommodated. Further, the ink jet recording apparatus 5 houses a printing mechanism portion 82 and the like configured by an ink cartridge 95 and the like for supplying ink to the ink jet recording head 94.

  A paper feed cassette 84 (or a paper feed tray) on which a large number of sheets 83 can be stacked can be detachably attached to the lower portion of the recording apparatus main body 81. Further, the manual feed tray 85 for manually feeding the paper 83 can be turned over. The paper 83 fed from the paper feed cassette 84 or the manual feed tray 85 is taken in, and after a required image is recorded by the printing mechanism unit 82, the paper is discharged to a paper discharge tray 86 mounted on the rear side.

  The printing mechanism 82 holds the carriage 93 slidably in the main scanning direction with a main guide rod 91 and a sub guide rod 92 which are guide members horizontally mounted on left and right side plates (not shown). An ink jet recording head 94 is mounted on the carriage 93 such that a plurality of ink discharge ports (nozzles) are arranged in a direction intersecting the main scanning direction and the ink droplet discharge direction is directed downward. The inkjet recording head 94 ejects ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). Further, the carriage 93 is mounted with replaceable ink cartridges 95 for supplying ink of each color to the ink jet recording head 94.

  The ink cartridge 95 has an air port (not shown) that communicates with the atmosphere above, an air port (not shown) that supplies ink to the ink jet recording head 94 below, and a porous body (not shown) filled with ink inside. ing. The ink supplied to the inkjet recording head 94 is maintained at a slight negative pressure by the capillary force of the porous body. Further, although the respective color heads are used here as the ink jet recording head 94, one head having nozzles for ejecting ink droplets of each color may be used.

  The carriage 93 is slidably fitted to the main guide rod 91 on the downstream side in the paper conveyance direction, and is slidably mounted on the sub guide rod 92 on the upstream side in the paper conveyance direction. In order to move and scan the carriage 93 in the main scanning direction, a timing belt 100 is stretched between a driving pulley 98 and a driven pulley 99 that are rotationally driven by the main scanning motor 97, so that the main scanning motor 97 is forward / reverse. The carriage 93 is reciprocated by the rotation. The timing belt 100 is fixed to the carriage 93.

  Further, the inkjet recording apparatus 5 conveys the fed sheet 83 by reversing the sheet feeding roller 101 for separating and feeding the sheet 83 from the sheet feeding cassette 84, the friction pad 102, the guide member 103 for guiding the sheet 83, and the like. A conveying roller 104 is provided. Further, the inkjet recording apparatus 5 is provided with a conveyance roller 105 that is pressed against the peripheral surface of the conveyance roller 104 and a leading end roller 106 that defines a feeding angle of the sheet 83 from the conveyance roller 104. As a result, the paper 83 set in the paper feed cassette 84 is conveyed to the lower side of the ink jet recording head 94. The transport roller 104 is rotationally driven by a sub-scanning motor 107 through a gear train.

  The printing receiving member 109 which is a paper guide member guides the paper 83 sent out from the conveying roller 104 corresponding to the movement range of the carriage 93 in the main scanning direction on the lower side of the ink jet recording head 94. On the downstream side of the printing receiving member 109 in the sheet conveyance direction, a conveyance roller 111 and a spur 112 that are rotationally driven to send out the sheet 83 in the sheet discharge direction are provided. Further, a paper discharge roller 113 and a spur 114 for sending the paper 83 to the paper discharge tray 86, and guide members 115 and 116 for forming a paper discharge path are provided.

  During image recording, the inkjet recording head 94 is driven in accordance with the image signal while moving the carriage 93, thereby ejecting ink onto the stopped paper 83 to record one line and transporting the paper 83 by a predetermined amount. After that, the next line is recorded. Upon receiving a recording end signal or a signal that the trailing end of the paper 83 reaches the recording area, the recording operation is terminated and the paper 83 is discharged.

  A recovery device 117 for recovering defective ejection of the inkjet recording head 94 is provided at a position outside the recording area on the right end side in the movement direction of the carriage 93. The recovery device 117 includes a cap unit, a suction unit, and a cleaning unit. The carriage 93 is moved to the recovery device 117 side during printing standby, and the ink jet recording head 94 is capped by the capping unit, and the ejection port portion is kept in a wet state to prevent ejection failure due to ink drying. Further, by ejecting ink not related to recording during recording or the like, the ink viscosity of all the ejection ports is made constant, and stable ejection performance is maintained.

  When ejection failure occurs, the ejection port of the ink jet recording head 94 is sealed with a capping unit, and bubbles and the like are sucked out from the ejection port with the suction unit through the tube. Also, ink or dust adhering to the ejection port surface is removed by the cleaning means, and the ejection failure is recovered. Further, the sucked ink is discharged to a waste ink reservoir (not shown) installed at the lower part of the main body and absorbed and held by an ink absorber inside the waste ink reservoir.

  As described above, the ink jet recording apparatus 5 includes the ink jet recording head 94 which is an embodiment of the droplet discharge head 4. Therefore, there is no ink droplet ejection failure due to vibration plate driving failure, stable ink droplet ejection characteristics can be obtained, and image quality can be improved.

  The preferred embodiments and the like have been described in detail above, but the present invention is not limited to the above-described embodiments and the like, and various modifications can be made to the above-described embodiments and the like without departing from the scope described in the claims. Variations and substitutions can be added.

  For example, as described above, the piezoelectric element according to the above embodiment can be used as a component part of a droplet discharge head used in an inkjet recording apparatus or the like, but is not limited thereto. The piezoelectric element according to the above-described embodiment may be used as a component such as a micro pump, an ultrasonic motor, an acceleration sensor, a temperature sensor, a two-axis scanner for a projector, an infusion pump, or the like.

  Further, the light applied to the light absorption layer is not limited to laser light, and any light may be used as long as it can heat the light absorption layer (light absorbed by the light absorption layer). For example, a flash lamp or the like can be used.

DESCRIPTION OF SYMBOLS 1 Wafer 2 Piezoelectric element 3, 4 Droplet discharge head 5 Inkjet recording device 10 Silicon substrate 10x Pressure chamber 11 Silicon oxide film 12 Titanium oxide film 13, 17 Platinum film 14 PZT film 15 Amorphous PZT film 16 PZT crystalline film 40 Nozzle plate 41 Nozzle 61 Scratch 62 Chipping 63 Liquid stain 69 Light-shielding mask 81 Recording device body 82 Printing mechanism 83 Paper 84 Paper feed cassette (or paper feed tray)
85 Manual feed tray 86 Paper discharge tray 91 Main guide rod 92 Subordinate guide rod 93 Carriage 94 Inkjet recording head 95 Ink cartridge 97 Main scanning motor 98 Drive pulley 99 Driven pulley 100 Timing belt 101 Paper feed roller 102 Friction pad 103 Guide member 104 Transport roller 105 Conveying roller 106 Leading end roller 107 Sub-scanning motor 109 Printing receiving member 111 Conveying roller 112 Spur 113 Paper discharge roller 114 Spur 115, 116 Guide member 117 Recovery device

"Highly textured laser annealed Pb (Zr0.52Ti0.48) O3 thin films", Applied Physics Letter, 99, 042903 (2011)

Claims (15)

Forming an amorphous film on one side of the substrate;
Irradiating light from the other side opposite to one side of the substrate and crystallizing a part of the amorphous film,
In the step of crystallizing a part of the amorphous film,
The amorphous film formed in a predetermined region including the outer peripheral portion on one side of the substrate remains without being crystallized, and the amorphous film formed in a region other than the predetermined region is crystallized to become a crystalline film. Thus, the manufacturing method of the wafer irradiated with the light. In the step of crystallizing a part of the amorphous film,
While relatively moving the light and the substrate, the other side of the substrate corresponding to the predetermined region is irradiated with light of a first irradiation power, and the substrate corresponding to a region other than the predetermined region is irradiated. The method for manufacturing a wafer according to claim 1, wherein the other side is irradiated with light having a second irradiation power larger than the first irradiation power. In the step of crystallizing a part of the amorphous film,
While relatively moving the light and the substrate, the other side of the substrate corresponding to the predetermined region is not irradiated with the light, and the other side of the substrate corresponding to a region other than the predetermined region is not irradiated The method of manufacturing a wafer according to claim 1, wherein the light is irradiated. Before the step of crystallizing a part of the amorphous film,
4. The wafer manufacturing method according to claim 2, further comprising a step of disposing an object that blocks the light on the other side of the substrate corresponding to the predetermined region.   The method for manufacturing a wafer according to claim 1, wherein the crystalline film is an oxide film.   The wafer manufacturing method according to claim 1, wherein the crystalline film is a complex oxide film.   The wafer manufacturing method according to claim 6, wherein the complex oxide film is formed of a ferroelectric material.   The method for manufacturing a wafer according to claim 1, wherein an outer peripheral portion of the substrate is an area within 10 mm from an outer edge of the substrate.   The wafer manufacturing method according to claim 1, wherein the outer peripheral portion of the substrate is an area within 5 mm from an outer edge of the substrate.   10. The method for manufacturing a wafer according to claim 1, wherein the crystalline film is crystallized so as to be preferentially oriented in any one of (100), (110), and (111). 11. A substrate,
An amorphous film formed in a predetermined region including an outer peripheral portion on one side of the substrate;
A crystalline film formed in a region other than the predetermined region,
The crystalline film is
A wafer which is a film obtained by irradiating light from the other side opposite to one side of the substrate to crystallize the amorphous film. A light absorption layer is formed on one side of the substrate,
The amorphous film and the crystalline film are formed on the light absorption layer,
The crystalline film is
The wafer according to claim 11, wherein the light irradiated from the other side of the substrate passes through the substrate and reaches the light absorption layer, and the light absorption layer is a film obtained by heating and crystallizing the amorphous film.   A piezoelectric element formed from the wafer according to claim 11 or 12.   A droplet discharge head comprising the piezoelectric element according to claim 13.   A droplet discharge apparatus comprising the droplet discharge head according to claim 14.

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