JP2002225291A - Ink jet type recording head, its manufacturing method and ink jet type recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet type recording head in which crosstalks are prevented and an ink discharge characteristic and printing quality are improved, its manufacturing method, and an ink jet type recording apparatus. SOLUTION: The ink jet type recording head is equipped with a channel forming substrate 10 in which pressure generating chambers 12 communicating with nozzle openings 21 are partitioned and a piezoelectric element 300 consisting of a lower electrode 60, a piezoelectric body layer 70 and an upper electrode 80 via a diaphragm 50 at one face side of the channel forming substrate 10. The ink discharge characteristic and printing quality are improved by forming to thin by grinding the channel forming substrate 10 forming the pressure generating chambers 12, and by arranging in high density the pressure generating chambers 12 in the state that rigidity of partition walls 11 partitioning the pressure generating chambers 12 is secured. Also, control of the thickness of the channel forming substrate 10 is easily done by disposing a recessed part 15 which becomes a thickness index on the grinding face of the channel forming substrate 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure generating chamber which communicates with a nozzle opening for discharging ink droplets, which is constituted by a vibrating plate. TECHNICAL FIELD The present invention relates to an ink-jet recording head for ejecting ink droplets by a method, a method for manufacturing the same, and an ink-jet recording apparatus.

[0002]

2. Description of the Related Art A part of a pressure generating chamber communicating with a nozzle opening for discharging ink droplets is constituted by a vibrating plate, and the vibrating plate is deformed by a piezoelectric element to pressurize the ink in the pressure generating chamber and to form an ink through the nozzle opening. Ink jet recording heads that eject droplets use a longitudinal vibration mode piezoelectric actuator in which piezoelectric elements expand and contract in the axial direction, and a flexural vibration mode piezoelectric actuator.
The types have been put to practical use.

In the former method, the volume of the pressure generating chamber can be changed by bringing the end face of the piezoelectric element into contact with the diaphragm, so that a head suitable for high-density printing can be manufactured. There is a problem in that a difficult process of cutting into a comb shape in accordance with the arrangement pitch of the openings and an operation of positioning and fixing the cut piezoelectric element in the pressure generating chamber are required, and the manufacturing process is complicated.

On the other hand, in the latter, a piezoelectric element can be formed on a diaphragm by a relatively simple process of sticking a green sheet of a piezoelectric material according to the shape of a pressure generating chamber and firing the green sheet. In addition, there is a problem that a certain area is required due to the use of flexural vibration, and that high-density arrangement is difficult.

On the other hand, in order to solve the latter disadvantage of the recording head, a uniform piezoelectric material layer is formed by a film forming technique over the entire surface of the diaphragm as disclosed in Japanese Patent Application Laid-Open No. 5-286131. A proposal has been made in which the piezoelectric material layer is cut into a shape corresponding to the pressure generating chambers by a lithography method, and a piezoelectric element is formed so as to be independent for each pressure generating chamber.

According to this, the operation of attaching the piezoelectric element to the vibration plate becomes unnecessary, so that not only can the piezoelectric element be manufactured by a precise and simple method called lithography, but also the thickness of the piezoelectric element can be reduced. This has the advantage that the thickness can be reduced and high-speed driving can be performed.

[0007]

However, in such an ink jet recording head, since the pressure generating chambers are formed to penetrate the flow path forming substrate, when the arrangement density of the pressure generating chambers is increased, the pressure generating chambers will not generate pressure. There is a problem that the thickness of the partition wall that partitions the chamber becomes thin, and crosstalk occurs between the adjacent pressure generating chambers, so that desired discharge characteristics cannot be obtained.

In view of such circumstances, it is an object of the present invention to provide an ink jet recording head, a method of manufacturing the same, and an ink jet recording apparatus in which crosstalk is prevented and ink ejection characteristics and printing quality are improved.

[0009]

According to a first aspect of the present invention, there is provided a flow path forming substrate in which a pressure generating chamber communicating with a nozzle opening is defined, and one surface of the flow path forming substrate. In the ink jet recording head, which includes a lower electrode, a piezoelectric layer and a piezoelectric element including an upper electrode via a vibration plate on the side, the thickness of the flow path forming substrate is provided on the other surface side of the flow path forming substrate. An ink jet recording head having a concave portion serving as an index.

In the first aspect, the thickness of the flow path forming substrate can be easily determined from the recess.

A second aspect of the present invention is the ink jet recording head according to the first aspect, wherein the flow path forming substrate is formed to a predetermined thickness by polishing the other surface side. It is in.

According to the second aspect, the thickness of the flow path forming substrate can be easily reduced, and the rigidity of the partition walls defining the pressure generating chamber can be increased to prevent crosstalk. Therefore, the pressure generating chambers can be arranged at a high density.

According to a third aspect of the present invention, in the first or second aspect, the thickness of the flow path forming substrate can be identified by any one of a position and a shape of the concave portion. In the head.

In the third aspect, the thickness of the flow path forming substrate can be easily determined based on one of the position and the shape of the concave portion.

A fourth aspect of the present invention is the ink jet recording head according to any one of the first to third aspects, wherein the flow path forming substrate is a silicon single crystal substrate.

In the fourth aspect, the pressure generating chamber and the recess can be formed easily and with high precision.

According to a fifth aspect of the present invention, in the fourth aspect, the main surface of the silicon single crystal substrate has a (110) orientation, and the concave portion is formed by anisotropic etching. Ink-jet recording head.

According to the fifth aspect, the concave portion can be easily and accurately formed by anisotropic etching.

According to a sixth aspect of the present invention, in the fifth aspect, the concave portion is inclined with respect to the (110) plane.
1) An ink jet recording head characterized in that the depth is determined at the intersection of the surfaces.

According to the sixth aspect, the concave portion can be easily and accurately formed at a predetermined depth.

According to a seventh aspect of the present invention, there is provided an ink jet recording apparatus comprising the ink jet recording head according to any one of the first to sixth aspects.

According to the seventh aspect, it is possible to realize an ink jet recording apparatus having uniform ink ejection characteristics.

According to an eighth aspect of the present invention, a pressure generation chamber is formed in a flow path forming substrate made of a silicon single crystal substrate, and film formation and lithography are performed on one side of the flow path forming substrate via a diaphragm. In a method of manufacturing an ink jet recording head for forming a lower electrode made of a thin film formed by a method, and a piezoelectric element made of a piezoelectric layer and an upper electrode, the method includes forming the piezoelectric element on one surface side of the flow path forming substrate through the diaphragm. After laminating and patterning the lower electrode, the piezoelectric layer, and the upper electrode sequentially to form the piezoelectric element, a polishing step of polishing the other surface side of the flow path forming substrate to a predetermined thickness is provided. To manufacture an ink jet recording head.

In the eighth aspect, the flow path forming substrate can be easily and reliably formed thin, and crosstalk between the pressure generating chambers can be prevented, so that the pressure generating chambers can be formed with a high arrangement density.

In a ninth aspect of the present invention based on the eighth aspect, in the polishing step, a plurality of concave portions having a predetermined depth and having different depths are formed on the other surface of the flow path forming substrate. A method of manufacturing an ink jet recording head, which is performed after the formation.

In the ninth aspect, the thickness of the flow path forming substrate can be easily determined by the recess.

According to a tenth aspect of the present invention, in the ninth aspect, in the polishing step, the recess is polished using the concave portion as a thickness index of the flow path forming substrate. It is in.

In the tenth aspect, the thickness of the flow path forming substrate can be easily controlled by using the concave portion as an index.

According to an eleventh aspect of the present invention, in the ninth or tenth aspect, after the polishing step, the thickness of the flow path forming substrate is identified by any one of the position and the shape of the concave portion. A feature of the invention is a method of manufacturing an ink jet recording head.

In the eleventh aspect, the thickness of the flow path forming substrate can be easily identified by either one of the position and the shape of the concave portion.

According to a twelfth aspect of the present invention, in any one of the eighth to eleventh aspects, the pressure generation chamber is formed on the other surface side of the flow path forming substrate before the polishing step. And a method of manufacturing an ink jet recording head.

In the twelfth aspect, by polishing the flow path forming substrate after forming the pressure generating chamber, the area to be polished is reduced, so that the polishing can be easily performed in a relatively short time.

According to a thirteenth aspect of the present invention, in any one of the ninth to eleventh aspects, the pressure generation chamber and the recess are simultaneously formed on the other surface side of the flow path forming substrate before the polishing step. The method for manufacturing an ink jet recording head is characterized in that it is formed.

In the thirteenth aspect, the manufacturing process can be simplified by forming the pressure generating chamber and the recess at the same time.

According to a fourteenth aspect of the present invention, in any one of the eighth to eleventh aspects, the pressure generation chamber is formed on the other surface side of the flow path forming substrate after the polishing step. To manufacture an ink jet recording head.

In the fourteenth aspect, by forming the pressure generating chamber after polishing the flow path forming substrate, the breakage of the partition wall due to polishing can be reliably prevented.

According to a fifteenth aspect of the present invention, in the fourteenth aspect, the pressure generating chamber is formed by forming a mask pattern on a polishing surface of the flow path forming substrate, and forming the flow path through the mask pattern. A method for manufacturing an ink jet recording head, characterized in that the head is formed by etching a formation substrate.

In the fifteenth aspect, the pressure generating chamber can be formed easily and with high precision.

According to a sixteenth aspect of the present invention, in any one of the ninth to fifteenth aspects, the principal surface of the silicon single crystal substrate has a (110) orientation, and the concave portion is formed by anisotropic etching. And a method for manufacturing an ink jet recording head.

In the sixteenth aspect, the concave portion can be easily and accurately formed by anisotropic etching.

According to a seventeenth aspect of the present invention, in the sixteenth aspect, the depth of the concave portion is determined at a point where a (111) plane inclined with respect to a (110) plane intersects. And a method of manufacturing an ink jet recording head.

According to the seventeenth aspect, the concave portion can be easily and accurately formed at a predetermined depth.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments.

(Embodiment 1) FIG. 1 is an exploded perspective view showing an ink jet recording head according to Embodiment 1 of the present invention. FIG. 2 is a plan view of the ink jet recording head, and FIG. FIG. 3B is a longitudinal sectional view of the pressure generating chamber of the ink jet recording head, and FIG.
FIG. 3C is a sectional view taken along the line BB ′ of FIG.

As shown in the figure, the flow path forming substrate 10 is made of a silicon single crystal substrate having a plane orientation (110) in this embodiment. One surface of the flow path forming substrate 10 is an opening surface,
On the other surface, an elastic film 50 having a thickness of 0.1 to 2 μm and made of silicon dioxide formed in advance by thermal oxidation is formed.

In the flow path forming substrate 10, pressure generating chambers 12 divided by a plurality of partition walls 11 are arranged in the width direction by anisotropic etching. The array density of the pressure generating chambers 12 is 360 per inch. On the outside in the longitudinal direction, there is formed a communication part 13 which forms a part of a reservoir 100 which communicates with a reservoir part of a reservoir forming substrate which will be described later and serves as a common ink chamber of each pressure generation chamber 12. Each of the generating chambers 12 communicates with one longitudinal end of the generating chamber 12 via an ink supply path 14.

Here, in the anisotropic etching, when the silicon single crystal substrate is immersed in an alkaline solution such as KOH, the substrate is gradually eroded, and the first (111) plane perpendicular to the (110) plane and the first (111) plane. The second (11) which forms an angle of about 70 degrees with the (111) plane and forms an angle of about 35 degrees with the above (110).
1) plane appears, and the etching rate of the (111) plane is about 1/18 as compared with the etching rate of the (110) plane.
This is performed using the property of being 0. By such anisotropic etching, two first (111)
Precision processing can be performed based on the depth processing of a parallelogram formed by two surfaces and two oblique second (111) surfaces, and the pressure generating chambers 12 can be arranged at high density.

In this embodiment, the long side of each pressure generating chamber 12 is formed by the first (111) plane, and the short side is formed by the second (111) plane. The pressure generating chamber 12 is provided on the flow path forming substrate 1.
It is formed by etching until it reaches the elastic film 50 almost through 0. Here, the elastic film 50 is
The amount attacked by the alkaline solution for etching the silicon single crystal substrate is extremely small. Further, each ink supply path 14 communicating with one end of each pressure generating chamber 12 is
It is formed shallower. That is, the ink supply path 14
Is formed by etching (half-etching) the silicon single crystal substrate halfway in the thickness direction. Note that the half etching is performed by adjusting the etching time.

The thickness of such a flow path forming substrate 10 may be determined by selecting an optimum thickness in accordance with the arrangement density of the pressure generating chambers 12. For example, if the arrangement density is about 180 per inch, , The thickness of the flow path forming substrate 10 is 220 μm
However, for example, in the case of arranging at a relatively high density of 200 or more per inch, the thickness of the flow path forming substrate 10 is preferably set to be relatively thin at 100 μm or less. This is because the partition 11 between the adjacent pressure generating chambers 12
This is because the arrangement density can be increased while maintaining the rigidity.
In this embodiment, the thickness of the flow path forming substrate is set to about 75 μm.
m.

A plurality of recesses 15 having a predetermined depth are formed on the opening-side surface of the flow path forming substrate 10.

Here, the flow path forming substrate 10 is formed thin by polishing the surface on the opening side, and when polished, the flow path forming substrate 10 is formed by one of the position and the shape of the concave portion 15. The thickness can be identified.

More specifically, the flow path forming substrate 10 is formed by forming a thin film such as a piezoelectric element described later on a wafer,
After being formed by etching, it is cut and formed for each chip size shown in FIG. 1, but is generally polished to a predetermined thickness in a wafer state before being cut. Therefore, the thickness of the flow path forming substrate 10 may vary depending on the position on the wafer.
Thereby, the thickness of each flow path forming substrate 10 can be easily identified.

That is, a plurality of recesses 15 having a predetermined depth
Is removed from the shallow recess 15 depending on the polishing amount when polishing the wafer to be the flow path forming substrate 10, and the remaining recess 15
And at least one of the shape of the concave portion 15
The thickness of each of the divided flow path forming substrates 10 can be easily identified. In this embodiment, since the thickness of the flow path forming substrate 10 is formed by polishing to a thickness of about 220 μm to about 75 μm, five recesses 15 having a depth of 135 μm to 155 μm and different depths of 5 μm are provided. did.

As described above, when the wafer is polished to a predetermined thickness and cut into the flow path forming substrate 10, for example, of the five concave portions 15, the two concave portions having a depth of 135 μm and 140 μm are formed.
Three concave portions 15 disappear, and three concave portions 15 of 145 μm to 155 μm remain. The thickness of the flow path forming substrate 10 is 70 μm.
Thicker and less than 80 μm.

The thickness of the flow path forming substrate 10 can be easily identified only by checking the position and the shape of the remaining concave portion 15. In addition, since the flow path forming substrate 10 can be classified according to the difference in thickness, if the driving waveform is selected according to the thickness of the flow path forming substrate 10, that is, the depth of the pressure generating chamber 12, The ink ejection characteristics of each ink jet recording head can be made uniform.

In this embodiment, the recess 15 is anisotropically etched (wet-etched) so as to be arranged vertically at one end of the pressure generation chamber 12 in the direction in which the pressure generation chamber 12 is arranged in the longitudinal direction of the pressure generation chamber 12. ). The depth of such a recess 15 is adjusted by changing the length of the opening of the mask pattern in the longitudinal direction of the pressure generating chamber 12.
That is, the flow path forming substrate 10 is formed of a silicon single crystal substrate having a plane orientation of (110), and when the recess 15 is formed by wet etching, the second (111) plane inclined with respect to the surface (110) plane is formed. Etching is automatically terminated at the intersecting depths. As described above, the length of the opening of the mask pattern forming the concave portion 15 in the longitudinal direction of the pressure generating chamber 12, that is, the length of the first (111) plane perpendicular to the (110) plane of the surface is set to be longer. If it is short, a shallow recess 15 is formed, and if it is long, a deep recess 15 is formed. Therefore, a plurality of recesses 15 having a predetermined depth can be formed easily and with high accuracy only by changing the length of the opening of the mask pattern in the longitudinal direction of the pressure generating chamber 12.

On the opening side of the flow path forming substrate 10,
A nozzle plate 20 provided with a nozzle opening 21 communicating with the pressure supply chamber 12 on the side opposite to the ink supply path 14 is fixed via an adhesive or a heat welding film. The thickness of the nozzle plate 20 is, for example, 0.1 to 1
mm, the coefficient of linear expansion is 300 ° C. or less, for example, 2.5 to
4.5 [× 10 ⁻⁶ / ° C.] glass ceramic,
Or made of non-rusting steel. The nozzle plate 20 entirely covers one surface of the flow path forming substrate 10 on one surface, and also serves as a reinforcing plate for protecting the silicon single crystal substrate from impact and external force.

Here, the size of the pressure generating chamber 12 for applying the ink droplet ejection pressure to the ink and the size of the nozzle opening 21 for ejecting the ink droplet depend on the amount of the ejected ink droplet, the ejection speed, and the ejection frequency. Optimized. For example,
When recording 360 ink droplets per inch, the nozzle openings 21 need to be formed with a diameter of several tens of μm with high accuracy.

On the other hand, the lower electrode film 60 having a thickness of, for example, about 0.2 μm and the piezoelectric layer 70 having a thickness of, for example, about 1 μm are formed on the elastic film 50 provided on the flow path forming substrate 10. When,
The upper electrode film 80 having a thickness of, for example, about 0.1 μm is laminated and formed by a process described later, and forms the piezoelectric element 300. Here, the piezoelectric element 300 includes the lower electrode film 60,
A portion including the piezoelectric layer 70 and the upper electrode film 80. Generally, one of the electrodes of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are connected to each of the pressure generating chambers 1.
It is structured by patterning every two. Here, a portion which is constituted by one of the patterned electrodes and the piezoelectric layer 70 and in which a piezoelectric strain is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion. In the present embodiment, the lower electrode film 60 is a common electrode of the piezoelectric element 300, and the upper electrode film 8
Although 0 is used as the individual electrode of the piezoelectric element 300, there is no problem even if this is reversed for convenience of a drive circuit and wiring. In any case, the piezoelectric active portion is formed for each pressure generating chamber. Also, here, the piezoelectric element 300
The diaphragm and the vibration plate that is displaced by driving the piezoelectric element 300 are collectively referred to as a piezoelectric actuator. In the example described above, the elastic film 50 and the lower electrode film 60 function as a diaphragm, but the lower electrode film may also serve as the elastic film.

The upper electrode film 80, which is an individual electrode of the piezoelectric element 300, is connected to an external wiring (not shown) through a lead electrode 90 extending from the vicinity of one end in the longitudinal direction of the piezoelectric element 300 onto the elastic film 50. Have been.

Further, the piezoelectric element 30 of the flow path forming substrate 10
On the 0 side, a reservoir forming substrate 30 having a reservoir portion 31 constituting at least a part of the reservoir 100 is joined. In the present embodiment, the reservoir section 31 penetrates the reservoir forming substrate 30 in the thickness direction, and
2 and is communicated with the communicating portion 13 of the flow path forming substrate 10 as described above, and each of the pressure generating chambers 1 is formed.
The two reservoirs 100 serve as a common ink chamber.

As such a reservoir forming substrate 30, it is preferable to use a material having substantially the same thermal expansion coefficient as that of the flow path forming substrate 10, for example, glass, ceramic material or the like. It was formed using a silicon single crystal substrate of the same material as that of No. 10. As a result, as in the case of the nozzle plate 20 described above, even when bonding is performed at a high temperature using a thermosetting adhesive, both can be reliably bonded. Therefore, the manufacturing process can be simplified.

The piezoelectric element 3 of the reservoir forming substrate 30
A piezoelectric element holding portion 32 capable of sealing the space is provided in a region opposed to the piezoelectric element 300 while securing a space that does not hinder the movement of the piezoelectric element 300. Sealed inside. In the present embodiment, the piezoelectric element holding section 32 is formed to have a size that covers the plurality of piezoelectric elements 300 arranged in parallel.

Further, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is joined to the reservoir forming substrate 30. Here, the sealing film 41 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μm).
One surface of the reservoir 31 is sealed by the sealing film 41. The fixing plate 42 is made of a hard material such as a metal (for example, stainless steel (SUS) having a thickness of 30 μm).
Etc.). The area of the fixing plate 42 facing the reservoir 100 is the opening 4 completely removed in the thickness direction.
Therefore, one surface of the reservoir 100 is sealed with only the sealing film 41 having flexibility, thereby forming a flexible portion 25 that can be deformed by a change in internal pressure.

Further, an ink introduction port 44 for supplying ink to the reservoir 100 is formed on the compliance substrate 40 substantially outside the central portion in the longitudinal direction of the reservoir 100. Further, the reservoir forming substrate 30 is provided with an ink introduction path 36 that communicates the ink introduction port 44 with the side wall of the reservoir 100. In the present embodiment, the ink is supplied to the reservoir 100 by one ink introduction port 44 and the ink introduction path 36. However, the present invention is not limited to this. For example, according to a desired ink supply amount, A plurality of ink introduction ports and ink introduction paths may be provided, or the opening area of the ink introduction ports may be increased to enlarge the ink flow path.

The ink jet recording head of this embodiment takes in ink from the ink inlet 44 connected to external ink supply means (not shown),
After the inside is filled with ink from 00 to the nozzle opening 21, each lower electrode film 60 corresponding to the pressure generating chamber 12 is formed according to a recording signal from an external driving circuit (not shown).
By applying a voltage between the upper electrode film 80 and the elastic film 50, the lower electrode film 60 and the piezoelectric layer 70 are flexed and deformed, the pressure in each pressure generating chamber 12 increases, and the nozzle opening 2
An ink droplet is ejected from 1.

Here, a method for manufacturing such an ink jet recording head will be described in detail. 4 to 6.
FIGS. 4 and 6 are cross-sectional views illustrating a method of manufacturing the ink jet recording head. FIGS. 4 and 6 are cross-sectional views in the direction in which the pressure generating chambers are arranged. FIG. It is sectional drawing of a setting direction.

First, as shown in FIG. 4A, a wafer of a silicon single crystal substrate to be
The elastic film 50 made of silicon dioxide and the first protective film 55 are formed by thermal oxidation in a diffusion furnace at 0 ° C. The first protective film 55 is used as a mask pattern for forming the concave portion 15 in a later step. In this embodiment, the silicon single crystal substrate has a thickness of 220 μm.

Next, as shown in FIG. 4B, the lower electrode film 60 is formed by sputtering on the elastic film 50 of the flow path forming substrate 10.
It is formed over the entire upper surface and patterned into a predetermined shape. Preferable materials for the lower electrode film 60 include platinum and iridium. This is because it is necessary to crystallize a piezoelectric layer 70 described later formed by a sputtering method or a sol-gel method by firing at a temperature of about 600 to 1000 ° C. in an air atmosphere or an oxygen atmosphere after the film formation. Because. That is, the material of the lower electrode film 60 must be able to maintain conductivity under such high temperature and oxidizing atmosphere.
In particular, as the piezoelectric layer 70, lead zirconate titanate (PZ
When T) is used, it is desirable that the change in conductivity due to the diffusion of lead oxide is small, and for these reasons, platinum and iridium are preferred.

Next, as shown in FIG. 4C, the piezoelectric layer 70 and the upper electrode film 80 are formed, and only the piezoelectric layer 70 and the upper electrode film 80 are etched to pattern the piezoelectric element 300. .

For example, in the present embodiment, the piezoelectric layer 70 is formed by applying and drying a so-called sol in which a metal organic substance is dissolved and dispersed in a catalyst, drying and gelling, and further firing at a high temperature to form a piezoelectric layer made of a metal oxide. The layer 70 was formed by using a so-called sol-gel method. As a material for the piezoelectric layer 70, a PZT-based material is suitable when used in an ink jet recording head. The method for forming the piezoelectric layer 70 is not particularly limited. For example, the piezoelectric layer 70 may be formed by a spin coating method such as a sputtering method or a MOD method (organic metal thermal coating decomposition method).

Also, a method of forming a precursor film of lead zirconate titanate by a sol-gel method, a sputtering method, a MOD method, or the like, and then crystallizing at a low temperature by a high-pressure treatment in an aqueous alkali solution may be used. Good.

Further, the upper electrode film 80 may be made of any material having high conductivity, and may be made of many metals such as aluminum, gold, nickel, and platinum, or a conductive oxide. In the present embodiment, platinum is formed by sputtering.

Next, as shown in FIG. 4D, a lead electrode 90 is formed over the entire surface of the flow path forming substrate 10 and is patterned for each piezoelectric element 300.

The above is the film forming process. After forming the film in this manner, the silicon single crystal substrate is subjected to anisotropic etching with the above-described alkali solution, and as shown in FIG. 5, the pressure generating chamber 12, the communicating portion 13, the ink supply passage 14, and the concave portion are formed. 15 is formed by anisotropic etching.
Note that FIG. 4 is a cross-sectional view in the direction in which the pressure generating chambers are juxtaposed, while FIG. 5 is a cross-sectional view in the direction in which the recesses 15 are juxtaposed along the longitudinal direction of the pressure generating chambers.

More specifically, first, as shown in FIG. 5A, an opening is formed by patterning a region where the concave portion 15 of the first protective film 55 formed on the other surface of the silicon single crystal substrate is formed. 15a is formed.

Here, the recess 15 formed in a later step
Is formed so that the depth gradually increases in the juxtaposition direction, the opening 15a of the first protective film 55 provided corresponding to the region where the concave portion 15 is formed is The first (1) perpendicular to the (110) plane of the crystal substrate
11) It is provided so that the length in the plane direction is gradually increased.

Next, as shown in FIG. 5B, the silicon single crystal substrate is subjected to anisotropic etching with the above-described alkaline solution to form a plurality of concave portions 15 at a predetermined depth.

At this time, the concave portion 15 is formed by the second (11) inclined with respect to the surface (110) by anisotropic etching.
1) Etching is performed to the depth where the surfaces intersect, and the process ends automatically. Therefore, the first (111) plane perpendicular to the (110) plane of the opening 15a formed in the first protective film 55 is formed.
A plurality of concave portions 15 having different depths can be formed at the same time due to the difference in the length of the surface. In the present embodiment, 13
The recess 15 having a depth of 5 μm to 155 μm and a depth of 5 μm.
Were formed.

Next, as shown in FIG. 5C, the surface of the flow path forming substrate 10 on the side of the concave portion 15 is polished, for example, by one-side lapping using diamond abrasive grains to reduce the thickness of the flow path forming substrate 10 to a predetermined thickness. In this embodiment, the thickness is approximately 75 μm.
Specifically, first, abrasive grains having a particle size of about 3 μm (polycrystalline)
Then, final polishing was performed using abrasive grains (polycrystal) having a particle size of about 1 μm.

When the flow path forming substrate 10 is polished as described above, the flow path forming substrate 10 gradually disappears from the shallow concave portion 15 among the plurality of concave portions 15 and is removed from at least one of the shape of the concave portion 15 and the position of the remaining concave portion 15. Ten thicknesses can be identified. In the flow path forming substrate 10 shown in FIG. 5 (c), two shallow recesses 15 out of the five recesses 15 disappear by polishing, and three deep recesses 15 remain, so that they are identified as thicker than 70 μm and thinner than 80 μm. can do.

In this embodiment, the flow path forming substrate 10
Since five recesses 15 having different depths of 5 μm from 135 μm to 155 μm are provided in
Differences in thickness of μm or more can be identified and classified. The number of the concave portions 15 is not particularly limited.
If 11 recesses having different depths of 2 μm from 135 μm to 155 μm are provided, a difference in thickness of 4 μm or more can be identified and classified. Further, it is not necessary to limit the depth of the concave portion 15 to the range of 135 μm to 155 μm, and the depth range and the depth difference of the concave portion are determined by the difference in the thickness of the flow path forming substrate to be classified and the performance of the polishing tool. It may be determined appropriately.

In this embodiment, the flow path forming substrate 10
The pressure generating chamber 12 is formed shallow by reducing the thickness of
The crosstalk between the pressure generating chambers 12 can be prevented by increasing the rigidity of the partition 11. Therefore, the pressure generating chamber 12
Can be formed at a high arrangement density, the ink ejection characteristics can be improved, and the nozzle openings 21 can be arranged at a high arrangement density to achieve high-resolution print quality.

In this embodiment, the flow path forming substrate 10
After the concave portion 15 is formed, the flow path forming substrate 10 is polished thinly, and then the pressure generating chamber 12 is formed. However, the present invention is not limited thereto. After simultaneously forming the portion 13 and the ink supply path 14 by anisotropic etching, the flow path forming substrate 10 may be polished thinly, and the pressure generating chamber 12 and the recess 15 may be formed in separate steps. Good.

Next, as shown in FIG. 6A, the polished surface of the flow path forming substrate 10 is patterned by forming a silicon dioxide layer at a low temperature (350 to 500 ° C.) by, for example, a TEOS-CVD method. A second protective film 56 is formed.

At this time, since the second protective film 56 is formed at a low temperature by the TEOS-CVD method, the flow path forming substrate 10
And the piezoelectric element 300 can be prevented from being damaged.

Next, as shown in FIG. 6B, the silicon single crystal substrate is anisotropically etched with the above-mentioned alkali solution to form the pressure generating chamber 12.

A large number of chips are simultaneously formed on one wafer by such a series of film formation and anisotropic etching, and after the process is completed, a flow path forming substrate of one chip size as shown in FIG. Divide every ten. At this time,
As described above, the thickness of the flow path forming substrate 10 can be identified and classified based on at least one of the shape and the position of the concave portion 15 of each flow path forming substrate 10. Then, the nozzle plate 20, the reservoir forming substrate 30, and the compliance substrate 40 are sequentially bonded to and integrated with the divided flow path forming substrate 10 to obtain an ink jet recording head.

(Embodiment 2) In Embodiment 2, a plurality of recesses are provided at predetermined positions of one wafer on which the flow path forming substrate 10 is formed, and the wafer is polished using the recesses as an index. It is an example.

Here, the manufacturing process of this embodiment will be described in detail. FIG. 7 is a perspective view of a wafer for explaining a manufacturing process of the ink jet recording head according to the second embodiment. The description of the manufacturing steps that are the same as those of the first embodiment will be omitted.

As in the first embodiment, the wafer 11
The elastic film 50, the piezoelectric element 300, and the lead electrode 90
After the formation, the five concave portions 15 having different depths as shown in the drawing.
Are provided at predetermined positions on the wafer 110. In the present embodiment, the concave group 16 is formed in a region other than the flow path forming substrate 10 to be cut.
And one was formed substantially at the center of the wafer 110.

The recess 15 of the recess group 16 formed substantially at the center of the wafer 110 may be provided over the adjacent flow path forming substrates 10.
0 may be provided. Further, the number of these concave groups 16 is not particularly limited.

The formation of the five concave portions 15 constituting the concave portion group 16 is the same as that of the first embodiment, and thus the duplicated description will be omitted.

Next, as shown in FIG. 7B, the plurality of recess groups 16 are polished using the thickness index of the wafer 110 to form a wafer 110 having a predetermined thickness.

Specifically, the piezoelectric element 30 of the wafer 110
The surface on the 0 side is polished by single-sided lapping using diamond abrasive grains using the plurality of concave portions 15 having a predetermined depth constituting each concave group 16 as an index, similarly to Embodiment 1 described above. . At this time, the plurality of recesses 15
The wafer 1 gradually disappears from the shallow recess 15, and the wafer 1 is removed from at least one of the shape of the recess 15 and the position of the remaining recess 15.
The thickness of 10 can be identified and the wafer 110 can be polished to a desired thickness.

The wafer 110 is polished so that the shape of the recess 15 polished to the middle of the recess 15 of each recess group 16 and the position of the remaining recess 15 are the same.
Can be formed with a substantially uniform thickness in the surface direction.

In this embodiment, each recess group 1
6, the five recesses 1 forming the recess group 16
5, if the two concave portions 15 of 135 μm and 140 μm disappear, and the three concave portions 15 of 145 μm to 155 μm are polished, the thickness of the wafer 110 is thicker than 70 μm, thinner than 80 μm, and substantially uniform. It can be formed to a thickness. Therefore, all the flow path forming substrates 10 cut from the wafer 110 have a substantially uniform thickness.

The subsequent formation of the pressure generating chamber 12 and bonding of the nozzle plate 20, the reservoir forming substrate 30, and the compliance substrate 40 are the same as in the first embodiment.

In the present embodiment, the recessed group 16 composed of the recessed portions 15 serving as a thickness index when the wafer 110 is polished is provided. However, the present invention is not limited to this. Embodiment 1 described above
Similarly to the above, the concave portion 15 may be provided for each flow path forming substrate 10.

(Other Embodiments) The first and second embodiments of the present invention have been described above. However, the basic structure of the ink jet recording head and the method of manufacturing the same is not limited to the above.

In Embodiments 1 and 2 described above, the flow path forming substrate 10 is a silicon single crystal substrate having a plane orientation of (110), and the opening 15 a of the first protective film 55, which is a mask pattern for forming the concave portion 15, is formed. A plurality of recesses 15 having different depths were formed by performing anisotropic etching while changing the length in the first (111) plane perpendicular to the (110) plane. However, the present invention is not limited thereto. Alternatively, a silicon single crystal substrate having a plane orientation of (100) may be used as the flow path forming substrate, and a plurality of concave portions having different depths may be formed in the concave portions by adjusting the dry etching time (half etching). Good. In any case, if a plurality of concave portions having a predetermined depth are provided in each of the flow path forming substrates 10, the thickness of the flow path forming substrates 10 can be easily identified and classified. Also, a plurality of recesses of a predetermined depth are provided on the wafer,
By polishing the wafer to a predetermined thickness by using the concave portion as an index, the thickness in the surface direction of the wafer can be made substantially uniform, and the thickness of the cut flow path forming substrate can be made uniform. .

In the method of manufacturing the ink jet recording head according to the first and second embodiments, the flow path forming substrate 1
0, a concave portion 15 is provided, and the flow path forming substrate 10 or the wafer 11
When polishing 0, the recess 15 was used as a thickness index.
Of course, the flow path forming substrate 10 may be polished without providing the recess 15. In any case, after the piezoelectric element 300 is formed on the flow path forming substrate 10 and then polished to a predetermined thickness, the rigidity of the partition wall 11 is increased, and even if the pressure generating chambers 12 are arranged with a high array density, the cross section is not crossed. Talk can be prevented. Therefore, it is possible to improve the ejection characteristics and achieve high quality printing.

The ink jet recording head according to the above-described embodiment forms a part of a recording head unit having an ink flow path communicating with an ink cartridge or the like, and is mounted on an ink jet recording apparatus. FIG.
FIG. 2 is a schematic diagram illustrating an example of the ink jet recording apparatus.

As shown in FIG. 8, in the recording head units 1A and 1B having the ink jet recording heads, cartridges 2A and 2B constituting ink supply means are detachably provided, and the recording head units 1A and 1B are provided.
The carriage 3 on which B is mounted is provided movably in the axial direction on a carriage shaft 5 attached to the apparatus main body 4. The recording head units 1A and 1B are, for example,
Each of them ejects a black ink composition and a color ink composition.

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

[0106]

As described above, according to the present invention,
By providing a concave portion serving as an index when polishing the flow path forming substrate on the flow path forming substrate, the thickness of the flow path forming substrate can be easily identified. Further, if the drive waveform is selected according to the identified thickness, the ink ejection characteristics can be made uniform. Furthermore, a flow path forming substrate having a substantially uniform thickness in the surface direction can be formed by polishing the concave portion as an index in a wafer state. Thereby, the manufacturing process can be simplified and the manufacturing cost can be reduced.

Further, by reducing the thickness of the flow path forming substrate by polishing, the pressure generating chambers can be arranged with a high arrangement density, so that the ink ejection characteristics can be improved and high printing quality can be realized.

[Brief description of the drawings]

FIG. 1 is a perspective view of an ink jet recording head according to a first embodiment of the present invention.

FIG. 2 is a plan view of the ink jet recording head according to the first embodiment of the present invention.

FIGS. 3A and 3B are cross-sectional views of an ink jet recording head according to Embodiment 1 of the present invention, in which FIG. 3A is a cross-sectional view of a pressure generating chamber in a longitudinal direction, and FIG. , (C)
FIG. 7B is a cross-sectional view taken along the line BB ′ of FIG.

FIG. 4 is a cross-sectional view illustrating a manufacturing process of the ink jet recording head according to Embodiment 1 of the present invention in a direction in which the concave portions are arranged.

FIG. 5 is a cross-sectional view illustrating a manufacturing process of the ink jet recording head according to the first embodiment of the present invention in a direction in which the concave portions are arranged.

FIG. 6 is a cross-sectional view in a direction in which pressure generating chambers are arranged in a manufacturing process of the ink jet recording head according to Embodiment 1 of the present invention.

FIG. 7 is a perspective view of a wafer showing a process of manufacturing an ink jet recording head according to Embodiment 2 of the present invention.

FIG. 8 is a schematic diagram of an ink jet recording apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Flow path forming substrate 11 Partition wall 12 Pressure generation chamber 13 Communication part 14 Ink supply path 15 Depression 16 Depression group 20 Nozzle plate 21 Nozzle opening 30 Reservoir formation substrate 40 Compliance substrate 50 Elastic film 60 Lower electrode film 70 Piezoelectric layer 80 Upper electrode Film 90 lead electrode 100 reservoir 110 wafer

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masaki Murai 3-3-5 Yamato, Suwa City, Nagano Prefecture Seiko Epson Corporation F-term (reference) 2C057 AF34 AF40 AF93 AG12 AG42 AP02 AP22 AP34 AQ02 BA04 BA14

Claims (17)

[Claims] 1. A flow path forming substrate in which a pressure generating chamber communicating with a nozzle opening is defined, and a lower electrode, a piezoelectric layer, and an upper electrode on one surface side of the flow path forming substrate via a vibration plate. An ink jet recording head comprising a piezoelectric element, wherein the other surface of the flow path forming substrate has a concave portion serving as a thickness index of the flow path forming substrate. 2. The ink jet recording head according to claim 1, wherein the flow path forming substrate is formed to a predetermined thickness by polishing the other surface side. 3. The ink jet recording head according to claim 1, wherein the thickness of the flow path forming substrate can be identified by any one of a position and a shape of the concave portion. 4. The ink jet recording head according to claim 1, wherein the flow path forming substrate is a silicon single crystal substrate. 5. The ink jet recording head according to claim 4, wherein a main surface of the silicon single crystal substrate has a (110) orientation, and the concave portion is formed by anisotropic etching. 6. The method according to claim 5, wherein the concave portion is formed as (11)
An ink jet recording head, wherein a depth is determined at a point where a (111) plane inclined with respect to a (0) plane intersects. 7. An ink jet recording apparatus comprising the ink jet recording head according to claim 1. 8. A pressure generation chamber is formed in a flow path forming substrate made of a silicon single crystal substrate, and a thin film formed by film formation and lithography on one surface side of the flow path forming substrate via a vibration plate. In a method for manufacturing an ink jet recording head for forming a piezoelectric element comprising a lower electrode, a piezoelectric layer, and an upper electrode, the lower electrode, the piezoelectric layer, and A step of polishing the other surface side of the flow path forming substrate to a predetermined thickness by sequentially laminating and patterning the upper electrodes to form the piezoelectric element, and manufacturing the ink jet recording head. Method. 9. The polishing method according to claim 8, wherein the polishing step is performed after forming a plurality of recesses having a predetermined depth and different depths on the other surface of the flow path forming substrate. Of manufacturing an ink jet recording head. 10. The method according to claim 9, wherein, in the polishing step, the concave portion is polished using the thickness of the flow path forming substrate as an index. 11. The ink jet recording head according to claim 9, wherein after the polishing step, the thickness of the flow path forming substrate is identified by any one of a position and a shape of the concave portion. Production method. 12. The method according to claim 8, wherein the pressure generating chamber is formed on the other surface side of the flow path forming substrate before the polishing step. Method. 13. The ink-jet method according to claim 9, wherein the pressure generating chamber and the concave portion are simultaneously formed on the other surface side of the flow path forming substrate before the polishing step. Method for manufacturing a recording head. 14. The method according to claim 8, wherein the pressure generating chamber is formed on the other side of the flow path forming substrate after the polishing step. . 15. The pressure generating chamber according to claim 14, wherein the pressure generating chamber is formed by forming a mask pattern on a polishing surface of the flow path forming substrate and etching the flow path forming substrate through the mask pattern. A method of manufacturing an ink jet recording head. 16. The method according to claim 9, wherein a main surface of the silicon single crystal substrate has a (110) orientation, and the concave portion is formed by anisotropic etching. . 17. The method according to claim 16, wherein:
A method for manufacturing an ink jet recording head, wherein a depth is determined at a point where a (111) plane inclined with respect to a (110) plane intersects.