JP2010228273A - Liquid ejecting head manufacturing method and liquid ejecting apparatus - Google Patents

Abstract

A liquid ejecting head manufacturing method and a liquid ejecting apparatus capable of maintaining print quality over a long period of time by a piezoelectric element having excellent crystallinity are provided.
SOLUTION: A step of forming a first electrode 60 on one side of a flow path forming substrate 10 in which a pressure generating chamber 12 communicating with a nozzle opening 21 is formed; and the first electrode 60 of the flow path forming substrate 10 is provided. A piezoelectric film forming process including a precursor film forming process for forming a piezoelectric precursor film thereon and a firing process for heating and crystallizing the piezoelectric precursor film to form a piezoelectric film is performed twice or more. A step of forming a plurality of stacked piezoelectric films, a reheating step of reheating the plurality of stacked piezoelectric films to form a piezoelectric layer 70, and the first of the piezoelectric layers 70. Forming the second electrode 80 on the surface opposite to the electrode 60, and the first baking step and the reheating step are heated at a higher temperature than the second and subsequent baking steps.
[Selection] Figure 2

Description

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

  A piezoelectric element used for a liquid ejecting head or the like is an element in which a dielectric film made of a piezoelectric material exhibiting an electromechanical conversion function is sandwiched between two electrodes. The dielectric film is made of, for example, crystallized piezoelectric ceramics. Has been.

  As a method for manufacturing such a piezoelectric element, a first electrode is formed on one surface side of a substrate (flow path forming substrate) by a sputtering method or the like, and then a piezoelectric layer is formed on the first electrode by a sol-gel method or MOD. The piezoelectric element is formed by forming the second electrode on the piezoelectric layer by sputtering and patterning the piezoelectric layer and the second electrode (see, for example, Patent Documents 1 to 3). ).

  When forming the piezoelectric layer by the above-described sol-gel method or MOD method, a precursor film forming step of forming a piezoelectric precursor film on the first electrode, and firing the piezoelectric precursor film to form the piezoelectric film The piezoelectric film forming process including the piezoelectric film forming process including the firing process is repeatedly performed to form a relatively thick piezoelectric layer. This is because if a relatively thick piezoelectric precursor film is baked at once, the piezoelectric film is broken such as cracks. That is, a piezoelectric layer having a relatively large thickness is obtained by repeatedly performing the piezoelectric precursor film forming step.

JP 2008-153552 A Japanese Patent No. 3405498 Japanese Patent No. 3105081

  However, a piezoelectric element that is further excellent in crystallinity and has a low displacement reduction rate even when repeatedly driven is desired. In addition, when the displacement reduction rate is high when the piezoelectric element is repeatedly driven, there is a problem that the ink discharge characteristics are lowered with the lapse of driving time, and uniform print quality cannot be maintained.

  Such a problem exists not only in the ink jet recording head but also in a liquid ejecting head that ejects liquid other than ink.

  SUMMARY An advantage of some aspects of the invention is that it provides a liquid ejecting head manufacturing method and a liquid ejecting apparatus capable of maintaining print quality over a long period of time with a piezoelectric element having excellent crystallinity. .

An aspect of the present invention that solves the above-described problems includes a step of forming a first electrode on one side of a flow path forming substrate in which a pressure generation chamber communicating with a nozzle opening is formed, and the first of the flow path forming substrate. Two or more piezoelectric film forming steps including a precursor film forming step of forming a piezoelectric precursor film on the electrode and a firing step of heating and crystallizing the piezoelectric precursor film to form a piezoelectric film are performed. Forming a plurality of stacked piezoelectric films, reheating a plurality of stacked piezoelectric films to form a piezoelectric layer, and the first electrode of the piezoelectric layer Forming a second electrode on the opposite surface, and the first baking step and the reheating step are heated at a temperature higher than that of the second and subsequent baking steps. A method of manufacturing a liquid jet head.
In such an embodiment, the heating temperature in the first firing step and the reheating step is higher than the heating temperature in the second and subsequent firing steps, so that the adhesion with the first electrode is excellent and the crystallinity is excellent. A piezoelectric layer can be obtained. In particular, a piezoelectric layer having a small half width of the (100) plane can be obtained, and even if the piezoelectric element composed of the first electrode, the piezoelectric layer, and the second electrode is repeatedly driven, the displacement of the piezoelectric element is reduced. The rate can be lowered. Thereby, it can maintain with the same liquid ejection characteristic over a long period of time.

  Here, in the second and subsequent firing steps, the piezoelectric precursor film is preferably heated at 600 ° C. According to this, it is possible to obtain a piezoelectric layer having a particularly small half width of the (100) plane.

  In the first piezoelectric film forming step, the piezoelectric precursor film forming step is performed once and then the firing step is performed once. In the second and subsequent piezoelectric film forming steps, the precursor is formed. It is preferable to repeat the film forming step twice or more and then perform the firing step once. According to this, in the first piezoelectric film forming step, by forming a relatively thin piezoelectric precursor film, even if baked and crystallized at a relatively high temperature, unevenness is formed on the surface. Less is. In the second and subsequent piezoelectric film forming steps, a relatively thick piezoelectric layer can be formed at low cost by forming two or more piezoelectric precursor films.

  Moreover, it is preferable to heat the said baking process of the 1st time at the temperature more than the temperature of the said reheating process. According to this, it is possible to obtain a piezoelectric layer having a particularly small half width of the (100) plane.

According to another aspect of the invention, there is provided a liquid ejecting apparatus including the liquid ejecting head manufactured by the manufacturing method according to the above aspect.
In this aspect, it is possible to realize a liquid ejecting apparatus that does not deteriorate print quality over a long period of time.

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. 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. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. 1 is a diagram illustrating a schematic configuration of a recording apparatus according to an embodiment.

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 FIG. FIG.

  In the present embodiment, the flow path forming substrate 10 is made of a silicon single crystal substrate, and an elastic film 50 made of silicon dioxide is formed on one surface thereof. A plurality of pressure generating chambers 12 are arranged in parallel in the width direction of the flow path forming substrate 10. In addition, 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 supply path 14 and a communication path 15. The communication part 13 communicates with a reservoir part 31 of a protective substrate, which will be described later, and constitutes a part of a reservoir that becomes a common ink chamber of each pressure generating chamber 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. 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. As described above, in this embodiment, the flow path forming substrate 10 is provided with the liquid flow path including the pressure generation chamber 12, the communication portion 13, the ink supply path 14, and the communication path 15.

  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 is made of, for example, glass ceramics, a silicon single crystal substrate, stainless steel, or the like.

  On the other hand, the elastic film 50 is formed on the side opposite to the opening surface of the flow path forming substrate 10 as described above, and the insulator film 55 is formed on the elastic film 50. Further, the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are laminated on the insulator film 55 by a process described later to constitute the piezoelectric element 300. Here, the piezoelectric element 300 refers to a portion including the first electrode 60, the piezoelectric layer 70, and the second electrode 80. In general, one electrode of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure generating chamber 12. In the present embodiment, the first electrode 60 is a common electrode of the piezoelectric element 300, and the second electrode 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 addition, here, a device having the piezoelectric element 300 provided so as to be displaceable is referred to as an actuator device. In the above-described example, the elastic film 50, the insulator film 55, and the first electrode 60 function as a diaphragm. However, the present invention is not limited to this. For example, the elastic film 50 and the insulator film 55 are provided. Instead, only the first electrode 60 may act as a diaphragm. Further, the piezoelectric element 300 itself may substantially serve as a diaphragm.

The piezoelectric layer 70 is a piezoelectric material having an electromechanical conversion effect formed on the first electrode 60, particularly a perovskite crystal structure represented by the general formula ABO ₃ among the piezoelectric materials (A site is an arbitrary metal element) , The B site is made of a ferroelectric material containing Pb, Zr, and Ti as metals. As the piezoelectric layer 70, for example, a ferroelectric material such as lead zirconate titanate (PZT) or a material obtained by adding a metal oxide such as niobium oxide, nickel oxide, or magnesium oxide to the ferroelectric material is suitable. Specifically, lead zirconate titanate (Pb (Zr, Ti) O ₃ ), lead lanthanum zirconate titanate ((Pb, La) (Zr, Ti) O ₃ ), or lead zirconium titanate magnesium niobate (Pb (Zr, Ti) (Mg, Nb) O ₃ ) or the like can be used.

  The piezoelectric layer 70 may be preferentially oriented in any of the (100) plane, the (110) plane, and the (111) plane, and the crystal structure thereof is rhombohedral, tetragonal, or tetragonal. Either a tetragonal system or a monoclinic system may be used. Note that the piezoelectric layer 70 of this embodiment is preferentially oriented in the (100) plane. Thus, the piezoelectric layer 70 preferentially oriented in the (100) plane can obtain a large amount of displacement with a low driving voltage, has excellent so-called displacement characteristics, and is suitably used for the ink jet recording head I. It is something that can be done. Incidentally, in order to preferentially orient the piezoelectric layer 70 in the (100) plane or the (110) plane, an orientation control layer having a predetermined crystal orientation is provided below or on the first electrode 60, or the first electrode 60 is provided. A crystal seed layer such as titanium that invalidates the orientation of the first electrode 60 is provided thereon, and the heat treatment temperature and the like when the piezoelectric layer 70 is formed can be adjusted. In the present invention, “crystals are preferentially oriented in the (100) plane” means that all crystals are oriented in the (100) plane and most crystals (for example, 90% or more) are ( 100) oriented in the plane.

  The piezoelectric layer 70 is formed thick enough to suppress the thickness so as not to generate cracks in the manufacturing process and to exhibit sufficient displacement characteristics. For example, in this embodiment, the piezoelectric layer 70 is formed with a thickness of about 0.5 to 5 μm.

  Further, each second electrode 80 which is an individual electrode of the piezoelectric element 300 is drawn from the vicinity of the end on the ink supply path 14 side and extended to the insulator film 55, for example, gold (Au) or the like. The lead electrode 90 which consists of is connected.

  On the flow path forming substrate 10 on which such a piezoelectric element 300 is formed, that is, on the first electrode 60, the insulator film 55, and the lead electrode 90, there is a reservoir portion 31 that constitutes at least a part of the reservoir 100. The protective substrate 30 is bonded via an adhesive 35. In the present embodiment, the reservoir portion 31 is formed across the protective substrate 30 in the thickness direction and across the width direction of the pressure generating chamber 12, and as described above, the communication portion 13 of the flow path forming substrate 10 is formed. The reservoir 100 is configured as a common ink chamber for the pressure generating 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 generating chamber 12 is provided in the flow path forming substrate 10, and a reservoir is provided on a member (for example, the elastic film 50, the insulator film 55, etc.) interposed between the flow path forming substrate 10 and the protective substrate 30. An ink supply path 14 that communicates with each pressure generating chamber 12 may be provided.

  A piezoelectric element holding portion 32 having a space that does not hinder the movement of the piezoelectric element 300 is provided in a region of the protective substrate 30 that faces the piezoelectric element 300. The piezoelectric element holding part 32 only needs to have a space that does not hinder the movement of the piezoelectric element 300, and the space may be sealed or unsealed.

  As such a 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, a glass, a ceramic material or the like. The silicon single crystal substrate was used.

  The protective substrate 30 is provided with a through hole 33 that penetrates the protective substrate 30 in the thickness direction. The vicinity of the end portion of the lead electrode 90 drawn from each piezoelectric element 300 is provided so as to be exposed in the through hole 33.

  A drive circuit 120 for driving the piezoelectric elements 300 arranged in parallel is fixed 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.

  In addition, 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, and one surface of the reservoir portion 31 is sealed by the sealing film 41. The fixing plate 42 is formed of a relatively hard material. 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 ink introduction port connected to an external ink supply means (not shown), and the interior from the reservoir 100 to the nozzle opening 21 is filled with ink. In accordance with a recording signal from 120, a voltage is applied between each of the first electrode 60 and the second electrode 80 corresponding to the pressure generating chamber 12, and the elastic film 50, the insulator film 55, the first electrode 60, and the piezoelectric body. By bending and deforming the layer 70, the pressure in each pressure generation chamber 12 is increased, and ink droplets are ejected from the nozzle openings 21.

  Hereinafter, a method for manufacturing such an ink jet recording head will be described with reference to FIGS. 3 to 7 are cross-sectional views in the longitudinal direction of the pressure generating chamber showing the method of manufacturing the ink jet recording head which is an example of the liquid ejecting head according to the embodiment of the invention. The piezoelectric layer 70 will be described using lead zirconate titanate, but it is needless to say that the piezoelectric layer 70 is not limited to this material and includes a material obtained by adding an additive to lead zirconate titanate.

  First, as shown in FIG. 3A, an oxide film 51 constituting the elastic film 50 is formed on the surface of a wafer 110 for flow path forming substrates, which is a silicon wafer and in which a plurality of flow path forming substrates 10 are integrally formed. To do.

  Then, as shown in FIG. 3B, an insulator film 55 made of an oxide film made of a material different from that of the elastic film 50 is formed on the elastic film 50 (oxide film 51).

  Next, as shown in FIG. 3C, the first electrode 60 is formed on the entire surface of the insulator film 55. The material of the first electrode 60 is not particularly limited. However, when lead zirconate titanate (PZT) is used as the piezoelectric layer 70, it is desirable that the material has little change in conductivity due to diffusion of lead oxide. . For this reason, platinum, iridium, etc. are used suitably as a material of the 1st electrode 60. FIG. Moreover, the 1st electrode 60 can be formed by sputtering method, PVD method (physical vapor deposition method), etc., for example.

  Next, a piezoelectric layer 70 made of lead zirconate titanate (PZT) is formed. Here, in this embodiment, the piezoelectric layer 70 is formed using a so-called sol-gel method. The manufacturing method of the piezoelectric layer 70 is not limited to the sol-gel method, and a MOD (Metal-Organic Decomposition) method may be used.

  A specific procedure for creating the piezoelectric layer 70 will be described. First, as shown in FIG. 4A, a piezoelectric precursor film 71 which is a PZT precursor film is formed on the first electrode 60 (precursor film forming step). That is, a sol (solution) containing a metal organic compound is applied onto the flow path forming substrate wafer 110 on which the first electrode 60 is formed (application step).

  Next, the piezoelectric precursor film 71 is heated to a predetermined temperature and dried for a predetermined time (drying step). For example, in the drying process of this embodiment, the sol applied on the flow path forming substrate wafer 110 was dried by holding at 150 to 170 ° C. for 3 to 30 minutes.

Next, the dried piezoelectric precursor film 71 is degreased by heating it to a predetermined temperature and holding it for a predetermined time (degreasing step). In this embodiment, the dried piezoelectric precursor film 71 is degreased by heating to 300 to 400 ° C. and holding for about 3 to 30 minutes. The degreasing referred to here is the separation of the organic components contained in the piezoelectric precursor film 71 as, for example, NO ₂ , CO ₂ , H ₂ O, etc., and the piezoelectric precursor film 71 is crystallized. That is, it means that the amorphous piezoelectric precursor film 71 is formed.

  Next, as shown in FIG. 4B, the piezoelectric precursor film 71 is crystallized by heating it to a predetermined temperature and holding it for a predetermined time to form a piezoelectric film 72 (firing step). In the present embodiment, the degreased piezoelectric precursor film 71 is preferably heated to 500 to 800 ° C. and fired.

  Next, as shown in FIG. 4C, when the first piezoelectric film 72 is formed on the first electrode 60, the first electrode 60 and the first piezoelectric film 72 are formed on their side surfaces. Are simultaneously patterned so as to be inclined. The patterning of the first electrode 60 and the first piezoelectric film 72 can be performed by dry etching such as ion milling, for example.

  Here, for example, when the first piezoelectric film 72 is formed after the first electrode 60 is patterned, the first electrode 60 is patterned by the photo process, ion milling, and ashing. The surface and a crystal seed layer such as titanium (not shown) provided on the surface are denatured. Then, even if the piezoelectric film 72 is formed on the altered surface, the crystallinity of the piezoelectric film 72 is not good, and the second and subsequent piezoelectric films 72 are also crystals of the first piezoelectric film 72. Since the crystal growth is influenced by the state, the piezoelectric layer 70 having good crystallinity cannot be formed.

  In contrast, if the first piezoelectric film 72 is formed and then patterned at the same time as the first electrode 60, the first piezoelectric film 72 is a second or subsequent piezoelectric film compared to a crystal seed such as titanium. As a seed (seed) for satisfactorily crystal-growing 72, the property is strong, and even if an extremely thin altered layer is formed on the surface layer by patterning, the crystal growth of the second and subsequent piezoelectric films 72 is not greatly affected. .

  And by repeating the piezoelectric film formation process which has the precursor film formation process (a coating process, a drying process, and a degreasing process) mentioned above and a baking process twice or more, as shown in FIG. A laminated piezoelectric film 72 having more than one layer is formed. At this time, the heating temperature in the first firing step is set higher than the temperature in the second and subsequent firing steps. For example, in the first baking step, heating is preferably performed at 500 to 800 ° C. for 5 to 30 minutes, and in the second and subsequent baking steps, heating is preferably performed at 500 to 700 ° C. for 5 to 30 minutes.

  Here, in each piezoelectric film forming step, the precursor film forming step may be repeated a plurality of times. In other words, after two or more piezoelectric precursor films 71 are stacked, a baking process may be performed in which the stacked piezoelectric precursor films 71 are simultaneously heated and crystallized. Therefore, the heating temperature in the first firing step refers to a temperature at which the single-layer piezoelectric precursor film 71 is fired, a temperature at which the multiple-layer piezoelectric precursor film 71 is fired, and the like. Similarly, the temperature of the second and subsequent firing steps includes the temperature at which the single-layer piezoelectric precursor film 71 is fired, the temperature at which the multiple-layer piezoelectric precursor film 71 is fired, and the like. Of course, you may change the frequency | count of performing a precursor film | membrane formation process by the 1st time and the 2nd time and after. In the present embodiment, in the first piezoelectric film forming step, one layer of the piezoelectric precursor film 71 is formed, and the one layer of piezoelectric precursor film 71 is heated and crystallized to be crystallized. A body film 72 is formed. In each of the second and subsequent piezoelectric film forming steps, two or more piezoelectric precursor films 71 are formed, and then the piezoelectric film 72 is formed by one firing. Therefore, in the first piezoelectric film forming step, the piezoelectric film 72 having a smaller thickness than the second and subsequent times is formed. When the heating temperature in the firing process is increased, the surface of the piezoelectric film 72 becomes rough, but the first piezoelectric film is formed even if the firing process in the first piezoelectric film forming process is performed at a high temperature. In the body film forming step, since a relatively thin piezoelectric film 72 is formed, the influence of unevenness due to high temperature is unlikely to occur. Moreover, the adhesive force between the first electrode 60 and the piezoelectric film 72 can be improved by performing the firing process of the first piezoelectric film forming process at a high temperature.

  Next, by reheating (post-annealing) the laminated piezoelectric film 72, the piezoelectric layer 70 composed of a plurality of piezoelectric films 72 is formed (reheating step). In the reheating step, the heating is performed at a temperature higher than the temperature of the second and subsequent firing steps. In the reheating process of this embodiment, it is preferable to heat at 670-800 degreeC for 5 to 30 minutes.

  Further, the reheating temperature is preferably lower than the heating temperature in the first baking step. That is, the first baking step is preferably performed at a temperature higher than the temperature of the reheating step. Incidentally, if the heating temperature in the firing step and the reheating step is too high, irregularities such as irregularities are formed on the surface of the piezoelectric layer 70 and the surface becomes rough. Therefore, the temperature is preferably 800 ° C. or lower.

  In addition, as a heating apparatus used in the drying process, the degreasing process, the firing process, and the reheating process, for example, a hot plate, an RTA (Rapid Thermal Annealing) apparatus that heats by irradiation with an infrared lamp, or the like can be used.

  Here, the difference in the characteristics of the piezoelectric layer 70 formed by the difference in temperature in each heating step (firing step, reheating step) was measured.

Example 1
As in the first embodiment described above, in the first piezoelectric film forming step, a single layer piezoelectric precursor film is formed and fired, and then in the second to fifth piezoelectric film forming steps, After the three layers of the piezoelectric precursor film 71 were formed, the firing step of firing the three layers of the piezoelectric precursor film 71 was performed once. That is, the piezoelectric film forming process was repeated five times, and finally a reheating process was performed to form a piezoelectric layer.

  In the first baking step, heating was performed at 737 ° C. for 300 seconds, and in each of the second to fifth baking steps, heating was performed at 600 ° C. for 300 seconds. Moreover, in the reheating process, it heated at 737 degreeC for 300 second. In each baking process and reheating process, RTA (Rapid Thermal Annealing) apparatus was used.

(Example 2)
A piezoelectric layer was formed by the same process and temperature conditions as in Example 1 except that the heating conditions of the first firing process were changed to 750 ° C. for 300 seconds.

Example 3
A piezoelectric layer was formed by the same process and temperature conditions as in Example 1 except that the heating condition of the first firing process was changed to 760 ° C. for 300 seconds.

(Comparative Example 1)
The piezoelectric layer was formed by the same process and temperature conditions as in the first embodiment except that the heating conditions of the second to fifth baking processes were changed to 737 ° C. for 300 seconds and the reheating process was not performed.

(Comparative Example 2)
A piezoelectric layer was formed by the same process and temperature conditions as in Example 1 except that the heating condition of the first firing process was changed to 600 ° C. for 300 seconds.

(Test example)
For the piezoelectric layers of Examples 1 to 3 and Comparative Examples 1 and 2 described above, the (100) half width of the laminated piezoelectric film before the reheating step and the piezoelectric layer ( 100) The half width of the plane was measured. In this embodiment, the half width was measured by the X-ray diffraction wide angle method (XRD). The results are shown in Table 1 below.

  When a piezoelectric layer (including stacked piezoelectric films) is measured by the X-ray diffraction wide angle method (XRD), diffraction intensity peaks corresponding to the (100) plane, (110) plane, (111) plane, etc. Will occur. The “half-value width” refers to the half-value width of the peak intensity corresponding to each crystal plane of the rocking curve indicated by the X-ray diffraction chart measured by the X-ray diffraction wide angle method (XRD). . In this embodiment, the half width of the X-ray diffraction wide angle method (XRD) was measured at 5 to 9 points in the plane of the flow path forming substrate wafer 110, and the average was obtained.

  Incidentally, the half width of the (100) plane is the deviation of the crystal lattice in the thickness direction of the piezoelectric layer (including the laminated piezoelectric films) (the direction connecting the first electrode 60 and the second electrode 80). Show. If the crystal lattice size in the thickness direction of the piezoelectric layer is uniform, the displacement characteristics of the piezoelectric layer, especially the displacement reduction rate when it is repeatedly driven, is lower. It is preferable to make the half width of the (100) plane showing as small as possible.

  As shown in Table 1, in Examples 1 to 3 in which the temperature of the first baking step was higher than the temperature of the second to fifth baking steps, Comparative Example 1 heated at the same temperature from the first to the fifth time and The half width of the (100) plane after the firing step is smaller than 2.

  Here, when Example 1 and Comparative Example 1 are compared, Example 1 and Comparative Example 1 have the same heating temperature in the first baking step, whereas Comparative Example 1 in the second to fifth baking steps. Is performed at a higher heating temperature. The half width of the (100) plane after the fifth firing step is smaller in Example 1 than in Comparative Example 1. Therefore, as in Comparative Example 1, simply increasing the heating temperature of all the firing steps cannot reduce the half width, and the temperature of the first firing step is set to the second to fifth firings. It has been found that the half width of the (100) plane can be reduced by increasing the height of the process.

  In Comparative Example 2, heating is performed in all the firing steps (first to fifth times) at the second to fifth firing steps and the heating temperature of Example 1, but in Comparative Example 1, the fifth time is performed. The half width of the (100) plane after the firing step is large.

  On the other hand, from the results shown in Table 1, in Examples 1 to 3 and Comparative Example 2, the half-value width of a small (100) plane can be obtained by performing the reheating step at a temperature higher than the second to fifth firing steps. It turns out that you can get. Further, as in Example 3, the half-value width can be further reduced by lowering the temperature of the reheating process relative to the temperature of the first baking process and increasing the temperature of the first baking process as compared with Example 2. It turns out that you can get.

  Thus, the half width of the (100) plane can be reduced by making the heating temperature in the first baking step and the reheating step higher than the heating temperature in the second and subsequent times. Thereby, the piezoelectric layer 70 having excellent crystallinity and a low displacement reduction rate can be obtained.

  After the piezoelectric layer 70 is formed in this way, the second electrode 80 made of, for example, iridium (Ir) is formed over the piezoelectric layer 70 as shown in FIG. Then, as shown in FIG. 5B, the piezoelectric layer 300 and the second electrode 80 are patterned in a region facing each pressure generating chamber 12 to form the piezoelectric element 300. Examples of the patterning method of the piezoelectric layer 70 and the second electrode 80 include dry etching such as reactive ion etching and ion milling.

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

  Next, as shown in FIG. 6A, 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. Then, as shown in FIG. 6B, the flow path forming substrate wafer 110 is set to a predetermined thickness.

  Next, as shown in FIG. 7A, a mask film 52 is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape. 7B, the flow path forming substrate wafer 110 is anisotropically etched (wet etching) using an alkaline solution such as KOH through the mask film 52, whereby the piezoelectric element 300 is formed. Corresponding pressure generating chambers 12, communication portions 13, ink supply passages 14, communication passages 15 and the like are formed.

  Thereafter, 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 a single chip size flow path forming substrate 10 and the like as shown in FIG. 1, the ink jet recording head of this embodiment is obtained.

  As described above, in the method for manufacturing the ink jet recording head according to the present embodiment, the heating temperature in the first baking step and the reheating step is higher than the heating temperature in the second and subsequent baking steps. The piezoelectric layer 70 having a small (100) plane half width and excellent crystallinity can be obtained. Incidentally, the piezoelectric layer 70 having a small half-value width of the (100) plane has a characteristic that the displacement reduction rate at which the displacement amount decreases when it is repeatedly driven is low. Therefore, it is possible to manufacture the ink jet recording head I that can maintain the ink ejection characteristics (liquid ejection characteristics) uniformly over a long period of time.

(Other embodiments)
As mentioned above, although one Embodiment of this invention was described, the fundamental structure of this invention is not limited to what was mentioned above. For example, in the first embodiment 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. For example, a material such as an SOI substrate or glass may be used.

  In the first embodiment described above, the first electrode 60 is formed over the entire surface on one side (on the insulator film 55) of the flow path forming substrate wafer 110, and then patterned into a predetermined shape, and then the piezoelectric body. Although the film 72 is formed, the present invention is not limited to this. For example, after the first electrode 60 is formed over the entire surface on one side (on the insulator film 55) of the flow path forming substrate wafer 110, the piezoelectric film is formed on the first electrode 60 in a single piezoelectric film forming step. When the body film 72 is formed, the first electrode 60 and the piezoelectric film 72 may be patterned at the same time. In this way, if the piezoelectric film 72 is formed by a single piezoelectric film forming process and then patterned simultaneously with the first electrode 60, the piezoelectric film 72 formed by the single piezoelectric film forming process has 2 The piezoelectric film 72 formed in the subsequent piezoelectric film forming steps is also strong as a seed for crystal growth, and even if an extremely thin altered layer is formed on the surface layer by patterning, the second film is formed. The crystal growth of the piezoelectric film 72 formed after the piezoelectric film forming step is not greatly affected.

  Further, the ink jet recording head manufactured in these embodiments constitutes a part of a recording head unit having an ink flow path communicating with an ink cartridge and the like, and is mounted on the ink jet recording apparatus. FIG. 8 is a schematic view showing an example of the ink jet recording apparatus.

  In the ink jet recording apparatus II shown in FIG. 8, the recording head units 1A and 1B having the ink jet recording head I are detachably provided with cartridges 2A and 2B constituting the ink supply means, and the recording head units 1A and 1B. Is mounted on a carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. The recording head units 1A and 1B, for example, are configured to eject a black ink composition and a color ink composition, respectively.

  The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted is moved along the carriage shaft 5. The On the other hand, the apparatus body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S that is a recording medium such as paper fed by a paper feed roller (not shown) is wound around the platen 8. It is designed to be transported.

  Further, in the ink jet recording apparatus II described above, the head units 1A and 1B having the ink jet recording head I are illustrated as being mounted on the carriage 3 and moving in the main scanning direction. The present invention can also be applied to a so-called line recording apparatus in which the ink jet recording head I is fixed and printing is performed simply by moving the recording sheet S such as paper in the sub-scanning direction.

  In the first embodiment described above, an ink jet recording head has been described as an example of a liquid ejecting head. However, the present invention is widely intended for all liquid ejecting heads, and is a liquid ejecting a liquid other than ink. Of course, the present invention can also be applied to an ejection 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.

  I ink jet recording head (liquid ejecting head), II ink jet recording apparatus (liquid ejecting apparatus), 10 flow path forming substrate, 12 pressure generating chamber, 13 communicating portion, 14 ink supply path, 15 communicating path, 20 nozzle plate, 21 nozzle opening, 30 protective substrate (crystal substrate), 31 reservoir portion, 40 compliance substrate, 50 elastic film, 55 insulator film, 60 first electrode, 70 piezoelectric layer, 71 piezoelectric precursor film, 72 piezoelectric film 80 second electrode, 90 lead electrode, 100 reservoir, 120 driving circuit, 121 connection wiring, 300 piezoelectric element

Claims (5)

Forming a first electrode on one side of the flow path forming substrate in which a pressure generating chamber communicating with the nozzle opening is formed;
A piezoelectric film having a precursor film forming step of forming a piezoelectric precursor film on the first electrode of the flow path forming substrate and a firing step of heating and crystallizing the piezoelectric precursor film to form a piezoelectric film. Performing a body film forming step twice or more to form a plurality of stacked piezoelectric films; and
A reheating step of reheating the plurality of laminated piezoelectric films to form a piezoelectric layer;
Forming a second electrode on the surface of the piezoelectric layer opposite to the first electrode,
The method of manufacturing a liquid jet head, wherein the first baking step and the reheating step are heated at a temperature higher than that of the second and subsequent baking steps.   2. The method of manufacturing a liquid jet head according to claim 1, wherein in the second and subsequent firing steps, the piezoelectric precursor film is heated at 600 ° C. 3.   In the first piezoelectric film forming step, the piezoelectric precursor film forming step is performed once and then the firing step is performed once. In the second and subsequent piezoelectric film forming steps, the precursor film formation is performed. The method of manufacturing a liquid jet head according to claim 1, wherein the firing process is performed once after the process is repeated twice or more.   4. The method of manufacturing a liquid jet head according to claim 1, wherein the first baking process is performed at a temperature equal to or higher than the temperature of the reheating process. 5.   A liquid ejecting apparatus comprising the liquid ejecting head manufactured by the manufacturing method according to claim 1.

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