JP2003291346A - Ink jet printer head and its producing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet printer head, and its producing method, in which a wafer can have a large area while eliminating crosstalk. <P>SOLUTION: The ink jet printer head is produced by forming a plurality of pressure chamber substrates (1) having one side provided with a plurality of pressure chambers on a silicon single crystal substrate (10). Recesses (12) are formed in one side of the pressure chamber substrate (1) while leaving the peripheral region and a plurality of pressure chambers are provided furthermore in the region where the recesses (12) are formed. Consequently, the pressure chamber substrate in the peripheral region is made thicker than the height of a sidewall separating the plurality of pressure chambers. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-demand type ink jet printer head for ejecting ink from nozzles to form dots on a recording sheet, and more particularly to applying electric energy to a piezoelectric body to displace a vibrating plate. By applying pressure to the pressure chamber where the ink is stored,
The present invention relates to a piezoelectric inkjet printer head that ejects ink and a method for manufacturing the same.

[0002]

2. Description of the Related Art As a prior art relating to the present invention, for example, US Pat. No. 5,265,315 discloses a structure of an ink jet printer head using a thin film piezoelectric element.

FIG. 20 is a sectional view showing the main part of a conventional ink jet printer head. This cross-sectional view shows a state in which a main part of the inkjet printer head is cut in the width direction of the elongated pressurizing chamber.

The main part of the ink jet printer head has a structure in which a pressure chamber substrate 500 and a nozzle substrate 508 are bonded together. The pressure chamber substrate 500 has a thickness of about 15
A diaphragm film 50 is formed on a silicon single crystal substrate 501 of 0 μm.
2, a lower electrode 503, a piezoelectric film 504, and an upper electrode 505 are sequentially formed. Silicon single crystal substrate 50
1, the pressurizing chambers 506a to 506c are provided with the silicon single crystal substrate
01 is formed by etching so as to penetrate in the thickness direction of 01. Each pressurizing chamber 50 of the nozzle forming substrate 508
Nozzles 509a-c are provided at positions corresponding to 6a-c.

A technique for manufacturing such an ink jet printer head is shown in US Pat. No. 5,265,315. In the manufacturing process of the pressure chamber substrate, the thickness 1
Silicon single crystal substrate (wafer) with a thickness of about 50 μm
Are divided into unit areas for providing individual pressure chamber substrates. A flexible diaphragm film for applying pressure to the pressure chamber is provided on one surface of the wafer. Further, a piezoelectric film that generates pressure is integrally formed on the diaphragm film at a position corresponding to the pressure chamber by a thin film manufacturing method such as a sputtering method or a sol-gel method. On the other surface of the wafer, a resist mask is formed and etching is repeated, and the width is 130 μm.
At, a group of pressure chambers, each of which is partitioned by a side wall having the same height as the thickness of the wafer, is formed. By these manufacturing methods,
For example, in the conventional inkjet printer head, the width of the pressure chambers 506a to 506c is 170 μm, and the resolution is about 90.
By orienting a row of nozzles 509 of dpi (dots per inch) on the recording paper at an angle of 33.7 degrees,
A print recording density of 300 dpi was achieved.

FIG. 21 is an explanatory view of the operating principle of the conventional ink jet printer head. 20 is the same as FIG.
FIG. 7 shows an electrical connection relationship with the main part of the inkjet printer head shown in FIG. Drive voltage source 5
One electrode of 13 is connected to the lower electrode 503 of the inkjet printer head via the wiring 514. The other electrode of the driving voltage source 513 is connected to the upper electrode 505 corresponding to each pressurizing chamber 506a-c via the wiring 515 and the switches 516a-c.

In the figure, the switch 51 of the pressurizing chamber 506b is
Only 6b is closed and the other switches 516a, 516 are open. Pressurization chamber 506 with switch 516 open
c indicates the standby time for ink ejection. At the time of discharging, the switch 516 is closed (516b). The voltage has the same polarity as the polarization direction of the piezoelectric film 504 indicated by the arrow A, in other words, the voltage is applied in the same manner as the polarity of the applied voltage during polarization.
The piezoelectric film 504 expands in the thickness direction and contracts in the direction perpendicular to the thickness direction. This contraction causes the piezoelectric film 504
The compressive shear stress acts on the interface between the diaphragm film 502 and the diaphragm film 502, and the diaphragm film 502 and the piezoelectric film 504 bend downward in FIG. Due to this deflection, the volume of the pressurizing chamber 506b is reduced and the ink droplet 512 is ejected from the nozzle 509b. Then, when the switch 516 is opened again (516a), the flexed diaphragm film 502 and the like are restored, and the pressure chamber 506a is filled with ink from the ink supply path (not shown) due to expansion of the volume of the pressure chamber.

[0008]

However, the structure of the conventional example has the following problems in order to improve the print recording density.

First, it was difficult to improve the recording density. The demand for high-definition printing has been increasing day by day for inkjet printer devices.
In order to meet this purpose, it is indispensable to reduce the amount of ink ejected from one nozzle of the inkjet printer head and to increase the density of the nozzle. If the nozzle is tilted in the scanning direction, the print density is further improved. Since the pressure chambers and the nozzles have the same pitch, it is necessary to increase the density of the pressure chambers and integrate them in order to achieve high-definition printing. For example, an inkjet printer head having a resolution of 180 dpi requires a pitch of pressure chambers of about 140 μm. That is, when the optimization calculation of the ink ejection pressure and the ejection amount is performed, it is ideal that the width of the pressurizing chamber is about 100 μm and the thickness of the side wall of the pressurizing chamber is about 40 μm.

However, there are structural restrictions on the side wall of the pressurizing chamber. That is, when pressure is applied to one pressurizing chamber,
If the height of the side wall is too high compared to its width, the steel property of the side wall will be insufficient. When the steel property of the side wall is insufficient, the side wall is bent and ink is ejected from the adjacent pressure chamber where ink should not be ejected (hereinafter, this phenomenon is referred to as “crosstalk”). For example, as shown in FIG. 21, when pressure is applied to the pressurizing chamber 506b, the sidewalls 507a and 507b are insufficient in steel property, and thus the sidewalls bend in the direction B. Then pressurizing chamber 5
Since the pressures of 06a and c also increase, ink is ejected from the nozzles 509a and 509c. This phenomenon becomes more noticeable as the resolution of the inkjet printer head is increased because the wall thickness becomes thinner.

In order to prevent crosstalk, the side wall may be thickened. However, in order to meet the demand for higher resolution of the inkjet printer head, the thickness of the side wall cannot be made too thick.

On the other hand, crosstalk can be prevented even if the height of the side wall is lower than the thickness of the side wall. However, in order to safely handle the wafer in the manufacturing process, the entire wafer is required to have sufficient mechanical strength, so that the wafer needs to have a certain thickness. For example, in the case of a silicon substrate having a diameter of 4 inches φ, if the thickness of the wafer is made thinner than 150 μm, the wafer will bend and it will be very difficult to handle during the manufacturing process.

Therefore, it has been difficult to secure the steel property of the side wall while improving the resolution and prevent the crosstalk.

Secondly, it was difficult to industrially and inexpensively produce an ink jet printer head. In order to reduce the unit price of the inkjet printer head, it is sufficient to increase the area of the wafer (for example, diameter 6 or 8 inches φ) and increase the number of pressure chamber substrates that can be formed at one time. However, as described above, it is necessary to increase the thickness of the wafer in order to obtain the required mechanical strength of the wafer itself as the area of the wafer is increased. If the thickness of the wafer is increased, crosstalk cannot be prevented as described above.

In view of the above problems, the first aspect of the present invention
It is an object of the present invention to provide an inkjet printer head capable of increasing the rigidity of the side wall of the pressurizing chamber and preventing crosstalk, and a manufacturing method thereof. A second object of the present invention is to provide a method for manufacturing an ink jet printer head that can increase the area of a silicon single crystal substrate.

[0016]

The present invention is applied to an ink jet printer head having a plurality of pressure chambers provided on one surface of a pressure chamber substrate. At the position opposite to the pressure chamber on the surface of the pressure chamber substrate opposite to the surface on which the pressure chamber is provided,
Grooves are formed. A diaphragm film for pressurizing the ink in the pressurizing chamber and a piezoelectric thin film element in which a piezoelectric film is sandwiched between upper and lower electrodes on the diaphragm film are formed in the groove. At least the width of the upper electrode is formed to be narrower than the width of the pressure chamber on the side of the piezoelectric thin film element, and also narrower than the width of the bottom surface of the groove.

Preferably, the pressure chamber substrate has a plane orientation (10
0) the silicon single crystal substrate, wherein the wall surface of the side wall partitioning the plurality of pressure chambers forms an obtuse angle with the bottom surface of the pressure chamber, and the wall surface of the side wall is from the (111) plane of the silicon single crystal substrate. Become.

Desirably, the wall surface of the groove formed on the surface of the pressure chamber substrate opposite to the surface on which the pressure chamber is provided forms an obtuse angle with the bottom surface of the groove, and the wall surface of the groove is formed on the silicon single crystal substrate ( 111)
Consists of faces.

Preferably, the pressure chamber substrate has a plane orientation (11
In the silicon single crystal substrate of 0), the wall surface of the side wall partitioning the plurality of pressure chambers forms a substantially right angle with the bottom surface of the pressure chamber,
The wall surface of the side wall is composed of the (111) plane of the silicon single crystal substrate.

Preferably, the wall surface of the groove formed on the surface of the pressure chamber substrate opposite to the surface on which the pressure chamber is provided is substantially perpendicular to the bottom surface of the groove, and the wall surface of the groove is the silicon single crystal substrate. Of (1
11) consists of faces.

Preferably, the wall surface of the groove formed on the surface of the pressure chamber substrate opposite to the surface on which the pressure chamber is provided forms an obtuse angle with the bottom surface of the groove.

Desirably, the lower electrode also serves as the diaphragm film. The present invention is an inkjet printer head in which a plurality of pressurizing chambers are provided on one surface of a pressurizing chamber substrate, and the pressurizing chamber substrate is provided with the pressurizing chamber on the opposite side thereof. A groove is formed at a position facing the pressure chamber, and in the groove, a diaphragm film for pressurizing ink in the pressure chamber, and a piezoelectric body in which a piezoelectric film is sandwiched between upper and lower electrodes on the diaphragm film. A thin film element is formed, and the diaphragm film is
It is formed of a material different from that of the pressure chamber substrate, at least the width of the upper electrode is formed narrower than the width of the pressure chamber on the piezoelectric thin film element side, and is smaller than the width of the bottom surface of the groove. It is narrowly formed.

According to the present invention, a step of forming a plurality of grooves on one surface of a silicon single crystal substrate, a step of forming a diaphragm film on the bottom surface of the groove, and a step of forming a piezoelectric film above the diaphragm film are performed. The method includes a step of forming a piezoelectric thin film element sandwiched between an electrode and a lower electrode, and a step of forming a pressurizing chamber at a position opposite to the bottom surface of the groove on the opposite surface of the silicon single crystal substrate.

Desirably, the step of forming the piezoelectric thin film element includes the step of forming a lower electrode, the step of forming the piezoelectric film on the lower electrode, and the step of forming an upper electrode on the piezoelectric film. And a step of removing a part of the upper electrode to make the effective width of the upper electrode narrower than the width of the pressurizing chamber.

Desirably, the step of forming the piezoelectric film is
It includes a step of forming a piezoelectric film precursor and a step of converting the piezoelectric film precursor into a piezoelectric film by performing heat treatment in an atmosphere containing oxygen.

Desirably, in the step of making the effective width of the upper electrode narrower than the width of the pressure chamber by removing a part of the upper electrode, the etching serving as a mask for etching is performed on the region of the upper electrode to be left. It includes a step of forming a pattern of the mask material and a step of removing the upper electrode region not covered with the etching mask material by etching.

Preferably, in the step of removing a part of the upper electrode to make the effective width of the upper electrode narrower than the width of the pressurizing chamber, the region of the upper electrode to be removed is irradiated with a laser so that the upper electrode is removed. Of removing a part of. The present invention is an inkjet printer head manufactured by any one of the above manufacturing methods.

The present invention is applied to an ink jet printer head obtained by forming a plurality of pressure chamber substrates, each having a plurality of pressure chambers on one surface of the pressure chamber substrate, on a silicon single crystal substrate. It The pressurizing chamber substrate has a concave portion formed on one surface of the pressurizing chamber substrate leaving a peripheral region, and a plurality of pressurizing chambers are further provided in the concave portion region where the concave portion is formed. Thus, the thickness of the pressurizing chamber substrate in the peripheral region is formed to be thicker than the height of the side wall separating the plurality of pressurizing chambers.

According to the present invention, since a thick peripheral region is left in each unit region like a lattice,
Even the silicon single crystal substrate on which the pressure chamber substrate is formed has high strength. This facilitates handling in the manufacturing process. Further, according to the present invention, since the mechanical strength of the silicon single crystal substrate can be increased,
By increasing the area of the substrate, more pressure chamber substrates can be provided.

Desirably, the nozzle plate is fitted in the recessed region.

Preferably, the ink jet printer head is provided with a plurality of pressure chambers on one surface of the pressure chamber substrate, and the locking portion is provided on one surface of the pressure chamber substrate on which the pressure chamber is provided. The nozzle plate, which is formed on the one surface, is provided with a locked portion with which the locking portion of the pressurizing chamber substrate is locked.

Desirably, the difference d between the thickness of the pressurizing chamber substrate in the peripheral region and the height of the side wall separating the pressurizing chamber is from the boundary between the recessed region and the peripheral region to the pressure chamber closest to this boundary. And the distance g to the side wall of the relation g ≧ d.

The present invention is a method for manufacturing an ink jet printer head, wherein a plurality of pressure chamber substrates having a plurality of pressure chambers provided on one surface are formed on a silicon single crystal substrate.
The silicon single crystal substrate is divided into unit areas for forming the pressure chamber substrate, and the surface of the pressure chamber substrate on which the pressure chamber is provided has a concave portion for each unit area, leaving a peripheral region around the unit area. The step of forming the concave portion and the step of forming the concave portion in the concave portion by the concave portion forming step further form a pressure chamber, and the thickness of the pressure chamber substrate in the peripheral region is set to the side wall separating the plurality of pressure chambers. A pressure chamber forming step of making the thickness thicker than the height.

The present invention is a method for manufacturing an ink jet printer head, in which a plurality of pressure chamber substrates having a plurality of pressure chambers provided on one surface are formed on a silicon single crystal substrate.
The silicon single crystal substrate is divided into unit areas for forming the pressure chamber substrate, and on the surface of the pressure chamber substrate where the pressure chamber is provided,
A pressurizing chamber forming step of forming a pressurizing chamber leaving a peripheral area in the peripheral portion of the unit area, and further forming a recess in the area where the pressurizing chamber is formed in the pressurizing chamber forming step to form a recessed area And a step of forming a recess for making the thickness of the pressure chamber substrate larger than the height of the side wall separating the plurality of pressure chambers.

The present invention is a method for manufacturing an ink jet printer head, in which a plurality of pressure chamber substrates having a plurality of pressure chambers provided on one surface are formed on a silicon single crystal substrate. A unit of a region where the pressure chamber substrate is formed on one silicon single crystal substrate is called a unit region. A concave region is formed on the surface of the pressure chamber substrate opposite to the surface on which the pressure chamber is provided.
The concave region is a region in which a concave region is formed for each unit region, leaving a peripheral region around the unit region.

Therefore, the thickness of the pressure chamber substrate in the peripheral region becomes thicker than the thickness of the pressure chamber substrate in the recessed region. Since a thick peripheral region is left in each unit region like a lattice, the strength of the substrate itself is high even if it is a silicon single crystal substrate on which the pressure chamber substrate is formed. This facilitates handling in the manufacturing process. Further, according to the present invention, since the mechanical strength of the silicon single crystal substrate can be increased, it is possible to increase the area of the substrate and provide more pressure chamber substrates.

A pressurizing chamber is formed on the surface of the substrate opposite to the surface on which the recessed region is provided by using a usual manufacturing method or the like. This pressurizing chamber is a space for ejecting ink, and is formed by processing such as resist formation, mask formation, exposure, development and etching.

Desirably, the recess forming step includes the following steps.

I) Processed layer forming step of forming a processed layer ii) Resist mask forming step of providing a resist on the processed layer and masking the resist iii) Area corresponding to the recessed area masked by the resist mask forming step Etching step iv) for etching the processed layer of iv) Recessed area etching step of further etching the silicon single crystal substrate in the area where the processed layer is removed by the etching step to form a recessed area v) Etched by the recessed area etching step Step of forming recessed layer to be processed in recessed region forming step Further, the following is desirable. In the piezoelectric thin film forming step, a piezoelectric thin film having a structure sandwiched by electrode layers is formed in the recessed region. This piezoelectric thin film is formed by etching to form a piezoelectric thin film element. In the resist forming step, a resist having elasticity is formed on the piezoelectric thin film (for example, a roll coater method). Next, the wafer provided with the resist is exposed in the exposure process, and the wafer exposed in the development process is developed. Through these steps, a resist (whether positive or negative) for forming the piezoelectric thin film element is left on the piezoelectric thin film. In the etching process,
A piezoelectric thin film element is formed by etching the piezoelectric thin film. In the step of forming the pressure chamber, on the surface opposite to the position on the recessed area where the piezoelectric thin film element is formed,
A pressure chamber is formed by etching or the like at a position corresponding to the piezoelectric thin film element.

When the formation of the pressure chamber substrates is completed, it is necessary to separate the pressure chamber substrates. At this time, for example, as described above, it is desirable to separate only the recessed region not including the peripheral region to separate the individual pressure chamber substrates. Further, as described above, the pressure chamber substrate may be separated including the peripheral region. At this time, each of the separated pressure chamber substrates becomes a substrate having a thick structure in the peripheral region and a thin structure in the recessed region, but it can be attached to the substrate of the inkjet printer head in its original shape. The present invention is an inkjet printer head manufactured by any one of the above manufacturing methods.

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the best mode for carrying out the present invention will be described with reference to the drawings.

<First Mode> In the first mode of the present embodiment, crosstalk is formed by forming a groove on the surface of the silicon single crystal substrate opposite to the surface on which the pressure chamber is provided, corresponding to the pressure chamber. To prevent the above.

(Structure of Inkjet Printer Head)
FIG. 1 shows a perspective view of the overall configuration of an inkjet printer head according to the present invention. Here, a type in which a common flow path for ink is provided in the pressure chamber substrate is shown.

As shown in FIG. 1, the ink jet printer head comprises a pressure chamber substrate 1, a nozzle unit 2 and a substrate 3 to which the pressure chamber substrate 1 is attached.

The pressure chamber substrate 1 is formed on a silicon single crystal substrate (hereinafter referred to as "wafer") by the manufacturing method according to the present invention, and then separated into each. Details of the method for manufacturing the pressure chamber substrate 1 will be described later. The pressure chamber substrate 1 is provided with a plurality of strip-shaped pressure chambers 106, and all the pressure chambers 1
The common channel 110 for supplying the ink to 06 is provided. Side walls 107 separate the pressurizing chambers 106. A diaphragm film (described later) is provided on the substrate 3 side (the surface not shown in FIG. 1) of the pressure chamber substrate 1, and pressure is applied to the diaphragm film on the substrate 3 side of the diaphragm film. A piezoelectric thin film element (described later) is provided.

The nozzle unit 2 is attached to the pressure chamber substrate 1 so as to cover it. When the pressure chamber substrate 1 and the nozzle unit 2 are bonded together, a nozzle 21 for ejecting ink droplets is provided at a position on the nozzle unit 2 that corresponds to the pressure chamber 106. Each pressurizing chamber 10
A piezoelectric thin film element (not shown) is arranged at 6. Wirings from the electrodes of each piezoelectric thin film element are collected on a wiring board 4 which is a flat cable and taken out of the base body 3.

The base 3 is a steel body such as a metal and can store the ink liquid and at the same time serves as a mount for the pressure chamber substrate.

FIG. 2 shows a main part of the ink jet printer head of this embodiment, that is, the layer structure of the pressure chamber substrate and the nozzle unit. Here, a type in which the common flow path of ink is formed on the reservoir chamber forming substrate instead of the pressure chamber substrate is shown.

The structure of the pressure chamber substrate 1 will be described later. The nozzle unit 2 includes a communication passage substrate 26 having a communication passage 27 formed therein, an ink supply passage forming substrate 24 having a plurality of ink supply holes 25, a reservoir chamber forming substrate 22 having an ink reservoir chamber 23, and a plurality of nozzles 21. It is configured by the nozzle forming substrate 20 that has. Pressure chamber substrate 1
The nozzle unit 2 and the nozzle unit 2 are joined by an adhesive. The ink reservoir chamber 23 has a function equivalent to that of the common flow path in FIG.

Note that, for the sake of simplification, FIG. 2 shows a structural diagram in which the nozzles are arranged in four rows and four rows, but in reality,
The number of nozzles and the number of rows are not limited, and any combination may be used.

FIG. 3 is a cross-sectional view of a main part of the ink jet printer head of this embodiment, showing a cross-sectional shape of the main part taken along a plane perpendicular to the longitudinal direction of the pressurizing chamber.
In the figure, the same structures as those in FIG. 1 and FIG. 2 are indicated by the same symbols, and the description thereof will be omitted. The pressure chamber substrate 1 is a silicon single crystal substrate 10 having a plane orientation (100) in the initial stage before etching. A groove 108 is formed on one surface (hereinafter referred to as “active element side”). The groove 108 is
The wall surface of the side wall is formed so as to form an obtuse angle with the bottom surface of the groove. Further, in the groove 108, the diaphragm film 102 and the lower electrode 1
03, the piezoelectric film 104 and the upper electrode 105 are integrally formed by a thin film process. The other surface of the silicon single crystal substrate 10 facing the groove 108 on the active element side (hereinafter referred to as "pressurizing chamber side")
A pressurizing chamber 106 is formed therein. The pressurizing chamber 106 is formed such that the wall surface of the side wall 107 separating the pressurizing chamber forms an obtuse angle with the bottom surface of the pressurizing chamber. When the nozzle unit 2 described with reference to FIG. 2 is bonded to the pressurizing chamber substrate 1, the structure of the main part of the inkjet printer head is obtained.

In this embodiment, a high density ink jet printer head of 180 dpi is assumed, and the pitch between the pressure chambers is about 140 μm. When manufacturing a head having such a high pressure chamber, the piezoelectric element is not a bulk piezoelectric element bonded, but a silicon single crystal is used by a thin film process as in this embodiment. It is necessary to integrally form it on the substrate 10.

When using the ink jet printer head of this embodiment, the pressure chamber 10 covered with the nozzle unit 2 is used.
6 is filled with ink. As the ink ejection operation, a voltage is applied to the piezoelectric thin film element at a position corresponding to the nozzle from which ink is desired to be ejected. As a result, the diaphragm film bends in the pressure chamber direction, and ink is ejected.

In this embodiment, since the groove 108 is provided, the depth of the pressurizing chamber 106 is much smaller (for example, 75 μm) than the thickness of the silicon single crystal substrate 10. Therefore, the side wall 107 of the pressurizing chamber has high rigidity. For example, when the central thin film piezoelectric element in FIG. 3 is driven and ink is ejected from the central nozzle 21b, ink is not ejected from the nozzles 21a and 21c on both sides thereof, so-called crosstalk does not occur.

Next, an embodiment of the method for manufacturing the pressure forming substrate will be described in detail.

(Embodiment 1) FIGS. 4 (a) to 4 (e) are sectional views showing steps of manufacturing the pressure chamber substrate of Embodiment 1. As shown in FIG. Here, for simplification of the drawing, only one pressurizing chamber of the pressurizing chamber substrates 1 formed in plural on the silicon single crystal substrate 10 (wafer) is shown.

FIG. 4A: First, a silicon single crystal substrate 10 having a plane orientation (100) is prepared. In this figure, it is assumed that the <110> axis is perpendicular to the plane of the drawing, the upper and lower surfaces of this substrate are (100) planes, and the thickness of the silicon single crystal substrate 10 is about 150 μm. This substrate 10 is, for example, 1
Wet thermal oxidation is performed in an oxygen atmosphere containing water vapor at about 000 to 1200 ° C. to form the thermal oxide film 1 on both surfaces of the substrate 10.
02 is formed. The thickness of the thermal oxide film 102 is set to a thickness required to serve as an etching mask for etching the substrate 10 described later, for example, 0.5 μm.

Further, the thermal oxide film 102 on the active element side forming the diaphragm film is pattern-etched in a photolithography process used in a normal thin film process. The pattern width is, for example, 80 μm. A mixed solution of hydrofluoric acid and ammonium fluoride is used as an etching solution for the thermal oxide film 102.

FIG. 4B: Next, for example, the density is 10%,
The substrate 10 is half-etched by immersing in a potassium hydroxide aqueous solution at 80 ° C. The etching selection ratio of silicon to the thermal oxide film is 40 with respect to the potassium hydroxide aqueous solution.
Since it is 0: 1 or more, only the region where the silicon substrate is exposed is etched. The side of the etching shape is
The (111) crystal plane has a trapezoidal bottom surface with the (100) plane, and the angle formed is an obtuse angle (180 degrees-about 54 degrees). The reason for this is that the etching rate when using an aqueous potassium hydroxide solution depends on the crystal plane orientation of silicon,
This is because the etching rate in the (111) plane direction is extremely slow compared to other crystal planes. The etching depth is controlled by the etching time, for example, 7 in the center of the substrate.
5 μm.

The thermal oxide film 102 on the etching mask and the thermal oxide film 102 on the back surface are once completely removed by etching with the hydrofluoric acid-based mixed solution, and then again on both surfaces of the substrate 10 by the wet thermal oxidation method described above. Thermal oxide film 10 with a thickness of 1 μm
Form 2. The portion of the thermal oxide film 102 formed in the trapezoidal groove portion functions as a diaphragm film.

The thermal oxide film 102 on the pressure chamber side is pattern-etched in a normal photolithography process in order to form a pressure chamber later.

FIG. 4C: Subsequently, a thin film piezoelectric element is formed on the thermal oxide film 302. The thin film piezoelectric element has a structure in which a piezoelectric film is sandwiched between upper and lower electrodes. As the lower electrode 103, for example, platinum having a film thickness of 0.8 μm is formed by a sputtering method. The composition of the piezoelectric body 104 is, for example, a material containing, as a main component, any one of lead zirconate titanate, lead magnesium niobate, lead nickel niobate, lead zinc niobate, and lead magnesium tungstate, or a solid solution thereof. It is a material used as an ingredient. As the film forming method, for example, a high frequency magnetron sputtering method using a sintered body target obtained by sintering a target material composition is used. When the substrate is not heated during film formation, the film formed by sputtering is an amorphous film that does not exhibit piezoelectric characteristics, and is referred to as a piezoelectric film precursor here. Next, the substrate on which the piezoelectric film precursor is formed is heat-treated in an atmosphere containing oxygen to be crystallized and converted into the piezoelectric film 104.

The upper electrode 105 has a film thickness of 0.1 μ, for example.
m platinum is formed by the sputtering method.

FIG. 4D: The thin film piezoelectric element is separated into individual units, and the width of the upper electrode is made narrower than the width of the pressurizing chamber so that the diaphragm film can be displaced. Specifically, in a normal photolithography process, patterning is performed so that a photoresist is left on the region of the upper electrode 105 to be left, and an unnecessary portion of the upper electrode is removed by ion milling or dry etching.

FIG. 4 (e): Finally, the exposed surface of the substrate 10 on the pressure chamber side is etched with an aqueous potassium hydroxide solution in the same manner as in the etching method for a silicon substrate described above, and the pressure chamber 106 is opened. Form. The etching of the substrate 10 is performed to a depth at which the thermal oxide film 102 is exposed.

Since the surface on which the active element is formed is attacked by the potassium hydroxide aqueous solution, a jig is used to prevent the potassium hydroxide aqueous solution from wrapping around the active element surface.

The formation of the pressure chamber substrate 1 of the ink jet printer head is completed by the above procedure.

In the above manufacturing method, the high frequency magnetron sputtering method was used as the method for manufacturing the piezoelectric film, but other thin film forming methods such as a sol-gel method, a metal organic thermal decomposition method, and a metal organic chemical vapor deposition method. Can be used.

(Examples 2 to 6) Table 1 including Example 1 is a list of other Examples having different structures from Example 1.

[0070]

[Table 1]

Corresponding to Embodiments 2 to 6, sectional views of the pressurizing chamber substrate taken along a plane perpendicular to the longitudinal direction of the pressurizing chamber are shown in FIGS.
Each is shown in FIG. In these figures, for simplicity of illustration,
Similar to FIG. 4, a sectional view of only one portion of the pressurizing chamber is shown.

FIG. 5 shows a sectional view according to the second embodiment. The second embodiment differs from the first embodiment in the pattern of the upper electrode 105. Patterning for element isolation was performed by directly irradiating a laser after forming the upper electrode 105. Therefore, although the upper electrode film 105 is left on the upper portion of the side wall 107, it does not function as the upper electrode because it is electrically separated from the upper electrode 105 on the upper portion of the pressurizing chamber 106. For the laser processing, for example, a YAG laser was used.

FIG. 6 shows a sectional view according to the third embodiment. The third embodiment differs from the second embodiment in that the side wall of the groove on the active element side has a steep angle. In this embodiment, the depth of the groove 108 on the active element side is deeper than that on the pressure chamber side.
In order to make the wall width of the side wall 107 equal, a dry etching method was used to form such a shape. In this way, if the depth of the pressure chamber 106 is made shallow and the width of the pressure chamber 106 on the active element side is set to be the same as that of the second embodiment, the width of the pressure chamber opening at the bottom of FIG. Therefore, higher density is possible.

FIG. 7 shows a sectional view according to the fourth embodiment. In this Example 4, the plane orientation of the silicon single crystal substrate is set to (11
In this example, the (0) plane is defined as the <1-12> axis in the longitudinal direction of the pressurizing chamber 106, that is, the direction perpendicular to the paper surface.

When the pressure chamber 106 is anisotropically etched using a potassium hydroxide aqueous solution, the rectangular pressure chamber 10 having two (111) planes substantially perpendicular to the substrate 10 is used.
6 can be formed. This is because, as described above, the etching rate in the case of using the potassium hydroxide aqueous solution depends on the crystal plane orientation of silicon, and the etching rate in the (111) plane direction is extremely slow as compared with other crystal planes. This is because.
Therefore, the density can be further increased as compared with the case of using the (100) plane silicon substrate. Since the active element side was also formed by anisotropic wet etching, the upper electrode 105 was patterned by laser processing.

FIG. 5 shows a sectional view according to the fifth embodiment. The fifth embodiment differs from the fourth embodiment in that the wall angle of the groove 108 on the active element side is gentle.

The groove 108 on the active element side was formed by the dry etching method. In this embodiment, the lower electrode 103,
When the piezoelectric film 104 and the upper electrode 105 are formed by the sputtering method or the like, the wraparound of the above film material into the inside of the groove 108 on the active element side during the sputtering film formation is improved, and those formed on the groove bottom surface part are improved. The film is more flat.

FIG. 9 shows a sectional view according to the sixth embodiment. The sixth embodiment differs from the fifth embodiment in that the width of the pressurizing chamber is
It is narrower than the groove width on the active element side.

If the width of the pressurizing chamber becomes wider than the groove width on the active element side (shown by the dotted line in the figure), when driving the thin film piezoelectric element to eject ink, the corner ( (Indicated by an arrow in the figure), the strength is weak and film breakage occurs. In the present embodiment, the width of the pressurizing chamber 106 is set to the width of the groove 108 on the active element side with a margin to prevent this.
It is a little narrower than the width of.

In each of the above-mentioned embodiments, a silicon thermal oxide film is used as the diaphragm film, but the diaphragm film is not limited to this. For example, a zirconium oxide film, a tantalum oxide film, a silicon nitride film, an aluminum oxide film may be used,
The diaphragm film itself may be eliminated, and the lower electrode film may also serve as the diaphragm film.

Further, as the solution for anisotropic etching of a silicon substrate, an aqueous solution of potassium hydroxide was used for explanation, but sodium hydroxide, hydrazine, tetramethyl.
Of course, another alkaline solution such as ammonium hydroxide may be used.

<Second Embodiment> The second embodiment of the present invention is as follows.
The present invention relates to a method for manufacturing an inkjet printer head, which is capable of forming a large number of pressure chamber substrates with small crosstalk even if the substrate area is large by forming recesses on the surface of the silicon single crystal substrate where the pressure chambers are provided.

(Wafer Structure) FIG. 10 shows a layout diagram of a pressure chamber substrate on a silicon single crystal substrate (wafer) according to the second embodiment. As shown in the figure, a plurality of pressure chamber substrates 1 are collectively formed on a silicon single crystal substrate 10.
The material of the substrate 10 may be single crystal silicon similar to that of the conventional substrate, but its area is wider than that of the conventional wafer. Since the area of the substrate is widened, the substrate is made thicker than before in order to ensure the mechanical strength in the manufacturing process. For example, the conventional substrate thickness is 1 to prevent crosstalk.
Although it was 50 μm or less, in the substrate 10 in the present embodiment, it is about 300 μm.

However, the area of the substrate can be increased as long as the handling in the manufacturing process is not hindered. For example, the area of the conventional substrate is limited to about 4 inches in diameter, but the substrate according to the present embodiment can have a diameter of 6 to 8 inches. As the area of the substrate is increased, the number of the pressurizing chamber substrates 1 that can be formed on one substrate can be increased, so that the cost can be further reduced.

Substrate 10 for providing one pressurizing chamber substrate 1
The upper area is called a unit area. The substrate 10 is divided into a grid by the substrate unit boundaries 13. The unit regions (pressurizing chamber substrates) are arranged vertically and horizontally. The pressure chamber substrate 1 is not arranged on the outer peripheral portion 11 of the substrate 10 in order to facilitate handling in the manufacturing process. The recess 12 described later
Is formed inside each unit region on the pressurizing chamber side of the substrate 10 as shown in FIG. No recess is provided in the boundary region between the pressure chamber substrates 1, that is, in the peripheral region of the unit region. Therefore, after the etching process, the substrate unit boundaries 13 having a large film thickness are left in a grid pattern. By leaving the substrate unit boundary 13, the strength of the substrate 10 itself is maintained even after the recess 12 is formed in the manufacturing process for forming the pressure chamber substrate 1. When the recess 12 is provided, the thickness at the position of the recess 12 is 150 μm, which is about the same as the conventional one, but the thickness at the position of the substrate unit boundary 13 is thicker than the conventional one, and high strength is maintained.

After the pressure chamber substrate 1 is formed, the silicon single crystal substrate 10 is cut and each pressure chamber substrate 1 may be separated along the substrate unit boundary 13. In the pressure chamber substrate 1 after separation, a thick peripheral region is left around the recessed region, so that the steel property of the pressure chamber substrate 1 itself can be maintained.
Pressurization chamber substrate 1 on base 3 of inkjet printer head
Since the contact area of the side wall of the pressure chamber substrate 1 in contact with the inner wall of the base 3 is large, the pressure chamber substrate 1 can be stably attached to the base 3.

Instead of providing the concave portion for each unit area as described above, as shown in FIG. 11, the concave portion 12b may be provided on the entire substrate leaving the outer peripheral portion 11 of the substrate 10. Since the outer peripheral portion 11 is left, the mechanical strength of the substrate 10 itself can be maintained.

Example 1 of Manufacturing Method Next, an example of a method of manufacturing the ink jet printer head of this embodiment will be described.

12 (a) to 13 (j) are sectional views showing the steps of manufacturing the pressure chamber substrate of this embodiment. In order to simplify the drawing, a cross-sectional view of one pressure chamber substrate 1 formed on a silicon single crystal substrate 10 (wafer) is schematically shown.

FIG. 12A: First, (110) having a predetermined size and thickness (for example, diameter 100 mm, thickness 220 μm)
An etching protection layer (thermal oxide film) 102 made of silicon dioxide is formed on the entire surface of the silicon single crystal substrate 10 having a surface by a thermal oxidation method.

The formation of the piezoelectric thin film can be considered in the same manner as in the first embodiment described above. That is, platinum serving as the lower electrode 103 is formed on the surface of the etching protection layer 102 on one surface (active element side) of the silicon single crystal substrate 10 by, for example, 800 nm by a thin film forming method such as a sputtering film forming method.
To form a film. At this time, ultrathin titanium, chromium or the like may be interposed as an intermediate layer in order to increase the adhesion between the platinum layer and the layers above and below it. The lower electrode 103 also serves as a diaphragm film.

The piezoelectric film precursor 104b is laminated thereon. In this example, a precursor of a PZT-based piezoelectric film having a molar composition ratio of lead titanate and lead zirconate of 55% and 45% is finally made to have a thickness of 0.9 μm by a sol-gel method. Up to 6 times, coating, drying and degreasing were repeated to form a film. As a result of various trial experiments, the chemical formula of this piezoelectric film is P
In the chemical formula represented by bCTiAZrBO3 [A + B = 1], A and C are 0.5≤A≤0.6 and 0.85≤C≤1.
If selected within the range of 10, it was possible to obtain piezoelectricity that can be practically used. The film forming method is not limited to this method, and high frequency sputter film forming, CVD, or the like may be used.

FIG. 12B: Next, the entire substrate is heated to crystallize the piezoelectric film precursor. In this example, the infrared radiant light source 17 is used, and the both surfaces of the substrate are held in an oxygen atmosphere at 650 ° C. for 3 minutes and then heated at 900 ° C. for 1 minute.
The piezoelectric film was crystallized by allowing the temperature to fall naturally. Through this step, the piezoelectric film precursor 24 was crystallized and sintered with the above composition to become the piezoelectric film 104.

FIG. 12C: An upper electrode film 105 is formed on the piezoelectric film 104. In this example, the upper electrode 105 is 2
Gold with a thickness of 00 nm was formed by a sputtering film forming method.

FIG. 12D: An appropriate etching mask (not shown) was applied to the upper electrode 105 and the piezoelectric film 104 in accordance with the position where the pressure chamber 106 is to be formed. After that, a predetermined separation shape was simultaneously formed by using ion milling.

FIG. 12E: The lower electrode 103 was also formed into a predetermined shape by ion milling after applying an appropriate etching mask (not shown).

FIG. 13 (f): A protective film against various chemicals that is further immersed in the active element side of the substrate 10 in a later step.
After forming (not shown for the sake of complexity), the etching protection layer 102 is etched with hydrogen fluoride in a region including at least the pressure chamber or the side wall of the surface of the substrate 10 on the pressure chamber side, and a window for etching is formed. 14 is formed.

FIG. 13 (g): Thereafter, the silicon single crystal substrate 20 in the region of the window 14 is set to a predetermined area by using an anisotropic etching solution, for example, an aqueous solution of potassium hydroxide having a concentration of about 40% and kept at 80 ° C. Anisotropically etch to depth d.
The predetermined depth d is a depth corresponding to a value obtained by subtracting the design value of the height of the side wall 107 from the thickness of the substrate 10. In this example, the depth d is half the thickness of the substrate 10 of 220 μm.
It was set to 10 μm. Therefore, the height of the side wall 107 is also 11
It becomes 0 μm. For forming the pressure chamber, an anisotropic etching method using an active gas such as parallel plate type reactive ion etching may be used. By this process,
As described with reference to FIG. 10, the concave portion 12 having a thin substrate and the substrate unit boundary 13 (step portion) are formed.

FIG. 13 (h): Next, on the pressure chamber side of the substrate 10 in which the concave portion 12 is formed, a silicon dioxide film is formed as an etching protection layer by a chemical vapor deposition method such as CVD, and then added. A mask that forms a pressure chamber is applied, and etching is performed with hydrogen fluoride. The sol-gel method may be used as the method for forming the silicon dioxide film, but since the piezoelectric film is already formed on the surface on the active element side, heating at a high temperature of 1000 ° C. or higher is required. The thermal oxidation method is not suitable because the crystallinity of the piezoelectric film is excluded.

FIG. 13 (i): Further, using an anisotropic etching solution, for example, a potassium hydroxide aqueous solution kept at 80 ° C. and having a concentration of about 17%, the substrate 10 is directed from the pressure chamber side to the active element side. Anisotropic etching is performed to form the pressure chamber 106 and the side wall 107. In addition, it is preferable that the distance g between the step and the closest pressurizing chamber with respect to the depth d is at least g ≧ d. Because, when patterning the etching protection layer, when applying a liquid resin resist, since the liquid may accumulate at the corners of this step, so that this accumulation does not adversely affect the dimensional accuracy of the pressure chamber, This is because it requires some escape.

FIG. 13 (j): A separate nozzle unit 2 is bonded to the pressure chamber substrate formed by the above process while positioning it by the side surface of the substrate unit boundary 13 (FIG. 1).
And FIG. 2).

In the first embodiment, the pressure chamber pitch is 70 μm.
m, width of pressurizing chamber 56 μm, length (depth direction in the figure) 1.
The width was 5 mm and the width of the side wall was 14 μm. Also, the pressurizing chamber 1
By arranging 128 elements per row, a printer head having a printing density of 720 dots / inch and 256 nozzles in two rows is realized.

This ink jet printer head was compared with a conventional ink jet printer head (that is, an ink jet printer head having a side wall width of 14 μm and a height of 220 μm).

In the conventional product, when one element (pressurizing chamber) is driven, the ejection ink velocity is 2 m / sec and the ejection ink amount is 20 n.
It was g. However, when the adjacent elements were driven at the same time, the ejection speed increased to 5 m / sec and the ejection amount increased to 30 ng, which was not a practical performance. This is due to the pressure loss due to the deformation of the side wall of the pressurizing chamber and the propagation of the pressure to the adjacent element, as described above.

On the other hand, according to the ink jet printer head of this embodiment, the ejection speed is 8 m / sec and the ejection amount is 22 ng under the same conditions as those of the conventional product, and even when a single element is driven, adjacent elements are driven. There was almost no difference in characteristics when both were driven simultaneously. That is, according to this embodiment,
This is because the rigidity can be increased to about 30 times or more by halving the height of the side wall to 110 μm.

Further, since the substrate unit boundary is left in a part of the pressure chamber substrate and its wall surface is used as a reference portion for positioning with the nozzle plate, the nozzle unit can be bonded to the pressure chamber substrate with high accuracy. .

FIG. 14 shows another embodiment in which a locking portion and a locked portion which serve as a reference for the positioning are formed. A protrusion 15 is provided as a locking portion in a portion of the pressure chamber substrate 1 where the pressure chamber 106 is not provided. When the nozzle unit 2 is bonded to the pressure chamber substrate 1, the protrusion 1
A positioning hole 16 is provided as a locked portion at a position on the nozzle unit 2 facing the nozzle 5. As in this example, it is also possible to arbitrarily form a protrusion or a positioning hole that positively locks the nozzle unit on the pressure chamber substrate.

(Second Embodiment of Manufacturing Method) FIG.
Example 2 of the manufacturing method of the inkjet printer head in the embodiment is shown. The steps up to (e) in the first embodiment described above are the same in this embodiment. Figure 15 (f): Substrate 1
A mask is applied to the pressure chamber side of 0 to form the pressure chamber 106, and the silicon dioxide film 102, which is an etching protection layer, is etched with hydrogen fluoride. Further, in the etching protection layer 102, the concave portion 12 of the first embodiment is formed.
The region corresponding to is etched to form the low film thickness portion 102a.

FIG. 15 (g): An anisotropic etching solution, for example, an aqueous solution of potassium hydroxide having a concentration of about 17% and kept at 80 ° C. was used to change the substrate 10 from the pressure chamber side toward the active element side. Isotropically etched.

FIG. 15H: After that, the low film thickness portion 102a is removed by etching with hydrogen fluoride to form a window 14 in which the silicon single crystal surface is exposed.

FIG. 15 (i): Then, the side wall 107 is reduced to a predetermined height by using an anisotropic etching solution, for example, an aqueous potassium hydroxide solution having a concentration of about 40% and kept at 80 ° C.

According to the second embodiment, the structure of the ink jet printer head of this embodiment can be obtained even by using these steps. In addition, in the process of FIG.
By adjusting the thickness of the low film thickness portion 102a to such a thickness that it disappears simultaneously with the etching of the substrate shown in FIG. 9G, the step shown in FIG. 11H can be omitted.

The substrate 1 on which the formation of the pressure chamber substrate has been completed
0 is separated into each pressure chamber substrate 1. At this time, if the pressure chamber substrates 1 are separated at the pitch P1 shown in FIG. 10, the pressure chamber substrates 1 similar to the conventional one can be separated. Further, each pressurizing chamber substrate 1 may be separated at a pitch of P2 (center line of substrate unit boundary 13). In this case, a thick side wall is formed around the pressure chamber substrate 1 after separation. As shown in FIG. 1, this side wall portion functions as an adhesive surface between the base body 3 and the pressure chamber substrate 1 when it is incorporated into the base body 3, so that it is easy to handle and the adhesive strength to the base body is increased. Has the effect of doing.

As described above, according to the second embodiment, the sidewalls are formed regardless of the original thickness of the silicon single crystal substrate by performing the etching for forming the recess on the pressure chamber side of the substrate. It can be formed at the intended height and its rigidity can be increased.

Further, if the step of forming the concave portion is performed immediately before the step of cutting and separating each pressurizing chamber substrate, the handling attention due to the reduction of the rigidity of the substrate can be minimized.

In addition, the locking portion can be integrally and highly accurately formed on the pressure chamber substrate, and the locking portion is used as a positioning reference with respect to the nozzle plate, so that the pressure chamber substrate and the nozzle plate can be aligned with each other. The relative position accuracy can be improved.

<Third Embodiment> The third embodiment of the present invention is as follows.
Unlike the second embodiment, a recess is formed on the surface of the silicon single crystal substrate opposite to the surface on which the pressure chamber is provided.

(Wafer Structure) FIG. 16 shows a layout diagram of a silicon single crystal substrate in the method of manufacturing the pressure chamber substrate according to the present embodiment. The layout in the present embodiment can be considered as in the second embodiment described above. That is, the area of the substrate 10 is larger than that of the conventional substrate, and
Thicken. Also, a unit area is provided as in the second embodiment.
However, in this embodiment, the recess 12 is provided on the active element side of the substrate.

In the following description, the shape of the front surface of the recess 12 and the unit area is square, and the width of the recess 12 is P.
1, the pitch of the unit area (between the unit boundaries 13 of the substrate) is P2
And

Next, a method of manufacturing the ink jet printer head in this embodiment will be described. 17 (a)-
18 (j) and FIGS. 18 (a) to 18 (f) show a silicon single crystal substrate 1
3 is a schematic view showing a cross section under the manufacturing assumption of 0. Each of the cross-sectional views shown in FIGS. 17 to 19 is a cross-sectional view of the substrate 10 in FIG. 16 taken along the line aa,
More specifically, the plurality of side walls 10 of the pressurizing chamber substrate 1.
7 is a view of the substrate forming process observed from a cross section crossing 7. The active element side corresponds to the upper surface of the substrate in FIGS.

(Concave Forming Step) FIG. 17 shows each step of forming a concave section in a substrate.

FIG. 17A: Wafer cleaning step: Oil and water on the substrate are removed for the pretreatment of the substrate.

FIG. 17B: Processed layer forming step: A silicon dioxide layer is provided on the substrate as a processed layer. For example, 110
Dry oxygen is flowed in a furnace at 0 ° C. for thermal oxidation for about 22 hours to form a thermal oxide film having a film thickness of about 1 μm. Alternatively, oxygen containing water vapor is caused to flow in a furnace at 1100 ° C. for thermal oxidation for about 5 hours to form a thermal oxide film having a thickness of about 1 μm. The thermal oxide film formed by these methods becomes a protective layer against etching.

FIG. 17C: Resist application step: A resist having a uniform thickness is applied by using a method such as a spinner method or a spray method. Then, in order to perform the pre-drying, the solvent is removed by heating at a temperature of 80 ° C to 100 ° C. To protect the thermal oxide film on the back surface of the wafer, the same resist as the resist formed on the front surface is deposited on the back surface.

FIG. 17 (d): Exposure: A mask is formed so as to leave the resist at the position of the unit boundary of the substrate, and exposure is performed with ultraviolet rays, X-rays, or the like.

FIG. 17E: Development: The exposed substrate is developed and rinsed by a spray method or dip. Although the positive resist is patterned here, it is of course possible to pattern the negative resist. After the development is completed, the resist is hardened and dried at 120 ° C to 180 ° C.

FIG. 17F: Etching step: The thermal oxide film is etched with a mixed solution of hydrofluoric acid and ammonium fluoride.

FIG. 17G: Resist removal: The remaining resist is stripped by using a stripping agent using an organic solvent or oxygen plasma.

FIG. 17 (h): Silicon etching forming step: The recess according to the present invention is formed by a wet etching method or a dry etching method.

As a wet etching method, for example, a mixed solution containing 18% hydrofluoric acid, 30% nitric acid and 10% acetic acid is used, and a predetermined depth (thickness of the pressure chamber substrate after formation) is used. As an appropriate thickness, for example, a depth such that the thickness of the wafer after etching becomes 150 μm).

It should be noted that silicon crystals have a difference in etching rate with respect to an alkaline solution. For this reason, if etching is performed using an alkaline solution, unevenness may occur after etching even if the initial wafer surface is smooth. For example, the height difference of the unevenness is about 5 μm
Thus, unevenness having a pitch of about 5 to 10 μm occurs. Therefore, be careful when etching with an alkaline solution.

FIG. 17 (i): Thermal oxide film etching step:
When silicon etching is performed, the thermal oxide film eaves as shown in FIG. 17 (h) occurs. In order to remove the eaves, the thermal oxide film on the entire area of the wafer is etched with a crystal solution of hydrofluoric acid.

FIG. 17 (j): Processed Film Formation: Again (b)
Apply a thermal oxide film to the entire area of the wafer in the same manner as
It is formed with a film thickness of m.

Through the above recess forming step, a plurality of recesses 12 can be formed in the substrate.

(Piezoelectric Thin Film Element Forming Step) As described above, when the concave portion 12 is formed, unevenness occurs on the surface of the substrate, so that it is difficult to form a resist having a uniform thickness. Therefore, in this embodiment, a photolithography method is used in which a resist is applied using a roller or the like by a method similar to offset printing.

FIG. 18 shows each step of forming a piezoelectric thin film element.

FIG. 18A, diaphragm film forming step: The thermal oxide film provided on the entire region of the wafer functions as the diaphragm film 102. Note that this step is merely a replacement of the same step as the step in FIG. 17 (j) with a different expression.

FIG. 18 (b) Piezoelectric thin film forming step: A piezoelectric thin film element is formed on the diaphragm film 102 in which the concave portion is formed. The piezoelectric thin film element has a structure in which a piezoelectric thin film is sandwiched between upper and lower electrode layers. The composition of the lower electrode 103 and the upper electrode 105, the composition of the piezoelectric film 104, and the step of heat-treating the piezoelectric film precursor are the same as those in the first embodiment described above.

FIG. 18 (c) Resist forming step: Next, resist is applied. However, since the substrate surface has irregularities,
A uniform resist cannot be applied by a conventional spray method or the like. Therefore, in order to provide the resist in the concave portion 12, a roller coater method is used in which a roller is used and the resist is applied by a method similar to offset printing. Laura
Made of elastic material such as rubber. The resist formed in the shape of the recess is transferred to the roller by a method similar to the offset printing. Then, this roller is rotated in close contact with the substrate 10 and the resist on the roller is transferred to the recessed area of the substrate 10. If a uniform resist can be applied, another method may be used regardless of the roller.

FIG. 18 (d) Mask / exposure step: Next, a mask is applied using a usual method (method shown in FIG. 3),
Expose. The mask pattern corresponds to the shape of the electrode.

FIG. 18 (e) Developing step: Development can also be carried out by using an ordinary method. Here, positive development is performed.

FIG. 18 (f) Etching process: Next, using ion milling, dry etching, or the like,
The electrode of the piezoelectric thin film element is completed by removing the unnecessary electrode portion and removing the resist.

Then, on the back surface of the substrate, for example, anisotropic etching using an active gas such as anisotropic etching or parallel plate reactive ion etching is performed to etch the space of the pressurizing chamber, The formation of the pressure chamber substrate 1 is completed. The formation of the pressurizing chamber can be considered in the same manner as in the second embodiment described above.

(Structure of Pressurization Chamber Substrate) FIG. 19 shows a sectional view of the silicon single crystal substrate 10 on which the formation of the pressure chamber substrate has been completed by the above-described manufacturing method. As shown in the figure, a recess 12 is formed on the active element side of the substrate 10. A lower electrode 103 is formed on the diaphragm film 102, and a piezoelectric film 104 provided with an upper electrode 105 is formed on the lower electrode 103. A pressure chamber 106 is formed on the pressure chamber side of the substrate 10 by ion milling or the like, and a side wall 107 separates the pressure chamber 106. Focusing only on the concave portion 12, it can be seen that it has the same structure as the conventional pressure chamber substrate formed on a silicon wafer having a thickness of 150 μm.

The separation of the pressurizing chamber substrate 1 from the substrate 10 can be considered in the same manner as in the second embodiment described above. That is, the pitch may be separated at the pitch P1 or the pitch P2 in FIG. The nozzle unit 2 is adhered to the separated pressure chamber substrate 1 (see FIG. 1).
And FIG. 2).

According to the third embodiment described above, since the thickness of the substrate can be increased, the mechanical strength can be increased. Therefore, handling in the manufacturing process becomes easy.

Further, although the thickness of the substrate is increased, the height of the side wall can be made the same as in the conventional case by providing the recessed region, so that the adverse effect of increasing crosstalk does not occur.

In addition, since the mechanical strength of the substrate is increased, the area of the substrate can be increased as compared with the conventional one. Since many pressure chamber substrates can be formed on one substrate at a time, the manufacturing cost can be significantly reduced.

[0149]

As described above, according to the present invention,
Since the height of the side wall is reduced and the rigidity of the wall is increased, it is possible to provide a high resolution inkjet printer head in which crosstalk does not occur.

Further, since the recessed region is formed on any surface of the silicon single crystal substrate, the thickness of the silicon single crystal substrate can be increased. Even after the pressurizing chamber substrate is formed, a thick peripheral region is left around the recessed region in the substrate like a lattice, so that the substrate itself is highly steel. Therefore, the substrates can be easily handled during manufacturing, and the yield can be increased.

Furthermore, according to the present invention, since the mechanical strength of the substrate can be increased, the area of the substrate can be increased and
More pressure chamber substrates can be formed at one time.
Therefore, the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an inkjet printer head according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of a main part of the inkjet printer head according to the first embodiment.

FIG. 3 is a main-portion cross-sectional view of the pressurizing chamber of Example 1 in the first mode in a plane perpendicular to the longitudinal direction.

FIG. 4 is a sectional view of a manufacturing process in a plane perpendicular to the longitudinal direction of the pressurizing chamber of Example 1 in the first embodiment.

FIG. 5 is a sectional view of the pressurizing chamber substrate taken along a plane perpendicular to the longitudinal direction of the pressurizing chamber according to the second embodiment of the first mode.

FIG. 6 is a sectional view of a pressurizing chamber substrate taken along a plane perpendicular to the longitudinal direction of the pressurizing chamber of Embodiment 3 of the first mode.

FIG. 7 is a sectional view of a pressurizing chamber substrate taken along a plane perpendicular to the longitudinal direction of the pressurizing chamber of Embodiment 4 of the first mode.

FIG. 8 is a sectional view of a pressurizing chamber substrate taken along a plane perpendicular to the longitudinal direction of the pressurizing chamber of Embodiment 5 of the first mode.

FIG. 9 is a sectional view of a pressure chamber substrate taken along a plane perpendicular to the longitudinal direction of the pressure chamber of Example 6 of the first mode.

FIG. 10 is a layout diagram on a silicon single crystal substrate of an ink jet print head according to a second embodiment of the present invention.

FIG. 11 is a modification of the layout on the silicon single crystal substrate of the inkjet print head in the second embodiment.

FIG. 12 is a manufacturing process cross-sectional view (No. 1) taken along a plane perpendicular to the longitudinal direction of the pressurizing chamber of Example 1 in the second mode.

FIG. 13 is a manufacturing process cross-sectional view (No. 2) on the plane perpendicular to the longitudinal direction of the pressurizing chamber of Example 1 in the second mode.

FIG. 14 is a diagram for explaining the connection between the pressure chamber substrate and the nozzle unit in the second embodiment.

FIG. 15 is a manufacturing step cross-sectional view in a plane perpendicular to the longitudinal direction of the pressurizing chamber of Example 2 in the second mode.

FIG. 16 is a layout diagram on a silicon single crystal substrate of an inkjet print head according to a third embodiment of the present invention.

FIG. 17 is a manufacturing step cross-sectional view (a recess forming step) on a plane perpendicular to the longitudinal direction of the pressurizing chamber in the third embodiment.

FIG. 18 is a manufacturing step cross-sectional view (piezoelectric thin film forming step) on a plane perpendicular to the longitudinal direction of the pressurizing chamber in the third embodiment.

FIG. 19 is a cross-sectional view of the silicon single crystal substrate in the third embodiment, taken along a plane perpendicular to the longitudinal direction of the pressurizing chamber.

FIG. 20 is a cross-sectional view of a conventional pressurizing chamber substrate taken along a plane perpendicular to the longitudinal direction of the pressurizing chamber.

FIG. 21 is a cross-sectional view taken along a plane perpendicular to the longitudinal direction of the pressurizing chamber for explaining the driving principle of the conventional pressurizing chamber substrate and its problems.

[Explanation of symbols]

1 ... Pressure chamber substrate 2 ... Nozzle unit 3 ... Base 4 ... Wiring board 10, 501 ... Silicon single crystal substrate (wafer) 11 ... Outer periphery 12, 12b ... Recess 13 ... Board unit boundary 14 ... window 15 ... Projection 16 ... Positioning hole 17 ... Radiant light source 20 ... Nozzle forming substrate 21 ... Nozzle 22 ... Reservoir chamber forming substrate 23 ... Ink reservoir chamber 24 ... Ink supply path forming substrate 25 ... Ink supply hole 26 ... Communication board 27 ... Communication passage 102, 502 ... Thermal oxide film (vibration plate film) 103, 503 ... Lower electrode 104, 504 ... Piezoelectric film 105, 505 ... Upper electrode 106, 506 ... Pressurizing chamber 107, 507 ... Side wall 108 ... Groove 110 ... Common flow path 509 ... Nozzle

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Manabu Nishiwaki             Seiko, 3-3-3 Yamato, Suwa City, Nagano Prefecture             -In Epson Corporation (72) Inventor Tsutomu Hashizume             Seiko, 3-3-3 Yamato, Suwa City, Nagano Prefecture             -In Epson Corporation F-term (reference) 2C057 AF40 AF93 AF15 AG16 AG16                       AG44 AG52 AG55 AP02 AP14                       AP23 AP32 AP34 AP52 AP56                       AP79 AQ02 BA04 BA14

Claims (12)

[Claims] 1. An ink jet printer head obtained by forming a plurality of pressure chamber substrates, each having a plurality of pressure chambers on one surface, on a silicon single crystal substrate, wherein the pressure chamber substrates are The pressurizing chamber in the peripheral region is formed by forming a recess on one surface of the pressurizing chamber substrate leaving a peripheral region, and further providing a plurality of pressurizing chambers in the recessed region in which the recess is formed. The thickness of the substrate
An ink jet printer head, characterized in that it is formed thicker than a height of a side wall separating the plurality of pressure chambers. 2. The ink jet printer head according to claim 1, wherein a nozzle plate is fitted in the recessed area. 3. An ink jet printer head having a plurality of pressure chambers provided on one surface of a pressure chamber substrate, wherein a locking portion is provided on one surface of the pressure chamber substrate provided with the pressure chambers. The nozzle plate formed with the above-mentioned one surface is provided with a locked portion to which the locking portion of the pressurizing chamber substrate is locked, on the nozzle plate bonded to the one surface. Inkjet printer head. 4. The difference d between the thickness of the pressurizing chamber substrate in the peripheral region and the height of the side wall separating the pressurizing chambers is increased from the boundary between the recessed region and the peripheral region to a position close to this boundary. 2. The ink jet printer head according to claim 1, wherein the distance g to the side wall of the pressure chamber has a relationship of g ≧ d. 5. A method of manufacturing an ink jet printer head, comprising forming a plurality of pressure chamber substrates having a plurality of pressure chambers on one surface on a silicon single crystal substrate, wherein the silicon single crystal substrate is A concave portion is formed by dividing the pressure chamber substrate into unit regions and forming a concave portion on the surface of the pressure chamber substrate on which the pressure chamber is provided, leaving a peripheral region around the unit region. Step, the pressure chamber is further formed in the concave region where the concave is formed by the concave forming step, and the thickness of the pressure chamber substrate in the peripheral region is
A pressurizing chamber forming step of making the pressurizing chamber thicker than a height of a side wall separating the plurality of pressurizing chambers from each other. 6. A method of manufacturing an ink jet printer head, comprising forming a plurality of pressure chamber substrates having a plurality of pressure chambers on one surface on a silicon single crystal substrate, wherein the silicon single crystal substrate is The pressure chamber is divided into unit regions for forming the pressure chamber substrate, and the pressure chamber is formed by leaving a peripheral region around the unit region on the surface of the pressure chamber substrate on which the pressure chamber is provided. A chamber forming step, and further forming a concave portion in a region where the pressure chamber is formed in the pressure chamber forming step to form a concave region, and setting the thickness of the pressure chamber substrate in the peripheral region to a plurality of the pressure chambers. And a recess forming step for making the side wall thicker than the height of the side wall. 7. A method of manufacturing an ink jet printer head, comprising forming a plurality of pressure chamber substrates having a plurality of pressure chambers on one surface on a silicon single crystal substrate, wherein the silicon single crystal substrate is The pressure chamber substrate is divided into unit areas for forming a substrate, and the surface of the pressure chamber substrate opposite to the surface on which the pressure chamber is provided has a concave portion for each unit area, leaving a peripheral region around the unit area. A step of forming a recess to form a region, and maintaining the mechanical strength of the silicon single crystal substrate by making the thickness of the pressure chamber substrate in the peripheral region thicker than the thickness of the pressure chamber substrate in the recess region. Inkjet printer head manufacturing method. 8. The step of forming a recess includes a step of forming a layer to be processed, a step of forming a layer to be processed, a step of forming a resist on the layer to be processed, and a step of masking the resist, and the step of forming the resist mask. An etching step of etching the processed layer in a region corresponding to the masked recessed region, and a silicon single crystal substrate in a region in which the processed layer is removed by the etching process are further etched to form the recessed region. The inkjet printer according to claim 7, comprising a recessed region etching step, and a recessed layer processing step of forming a processed layer in the recessed region etched in the recessed region etching step. Head manufacturing method. 9. A piezoelectric thin film forming step of forming a piezoelectric thin film sandwiched by electrode layers in the concave area formed by the concave forming step, and a piezoelectric thin film forming step of using a roller having elasticity. A resist forming step of forming a resist on the formed piezoelectric thin film, an exposing step of exposing the silicon single crystal substrate provided with the resist by the resist forming step, and the silicon single crystal exposed by the exposing step Corresponding to the developing step of developing the substrate, the etching step of forming the piezoelectric thin film element by etching the piezoelectric thin film provided with the resist in the developing step, and the piezoelectric thin film element formed by the etching step. A pressure chamber forming step of forming the pressure chamber at a position on the other surface of the silicon single crystal substrate. The method of manufacturing an inkjet printer head according to claim 7, wherein 10. After separating the pressure chamber substrate, when separating the pressure chamber substrate from each of the unit regions, only the concave region not including the peripheral region is separated from the silicon single crystal substrate. 10. The method for manufacturing an inkjet printer head according to claim 5, further comprising a step of separating each of the pressure chamber substrates. 11. After the pressure chamber substrate is formed, when the pressure chamber substrate is separated from each unit region, the pressure chamber substrate including the peripheral region is separated from the silicon single crystal substrate. 10. The method for manufacturing an ink jet printer head according to claim 5, further comprising a step of separating each of the pressure chamber substrates. 12. An ink jet printer head manufactured by the manufacturing method according to claim 5.