JP2002086738A - Method of making liquid jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the cost. SOLUTION: A second substrate 23 having electrodes 15 at both faces thereof is laminated on a first substrate 21 on which an ejection chamber 6 and a diaphragm 10 are formed and then they are stuck with each other. After that, the first substrate 21 is cut along a face perpendicular to a laminating direction to be divided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a droplet discharge head.

[0002]

2. Description of the Related Art Generally, ink droplets are ejected as an ink jet head which is a liquid droplet ejection head in an ink jet recording apparatus used for an image recording apparatus (including an image forming apparatus) such as a printer, a facsimile, a copying machine, a plotter and the like. A nozzle and a liquid chamber with which the nozzle communicates (also referred to as a discharge chamber, an ink flow path, an ink chamber, a pressure chamber, a pressurized chamber, a pressurized liquid chamber, etc.) and a first wall forming a wall of the discharge chamber 2. Description of the Related Art There is an electrostatic inkjet head that includes a diaphragm serving also as an electrode and an electrode (second electrode) facing the diaphragm, and deforms and displaces the diaphragm with electrostatic force to discharge ink droplets from nozzles.

As such an electrostatic ink jet head, for example, Japanese Patent Application Laid-Open No. 6-71882 and Japanese Patent Application Laid-Open
As disclosed in Japanese Patent Publication No. 50601, a silicon substrate is used as a substrate for forming a discharge chamber and a diaphragm, and borosilicate glass (Pyrex (registered trademark)) is used for a substrate on which electrodes are provided.
Glass) or a silicon substrate.

In order to perform high-definition and high-density recording with such an ink-jet head, it is necessary to generate minute ink droplets. Therefore, it is required that the ejection chamber has a small volume.

Therefore, in the conventional ink jet head, for example, as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 6-71882, the height of the discharge chamber is specified to be 230 μm.
Further, as disclosed in Japanese Patent Application Laid-Open No. H11-993, the height of the discharge chamber is specified to be 100 to 160 μm, and in order to achieve the processing accuracy of the discharge chamber, a predetermined height of the discharge chamber is determined using a silicon wafer. It has been proposed to grind and polish to the point.

[0006]

However, in consideration of handling properties, the thickness of a normal silicon wafer is 400 to 650 μm in the case of a 150 mm diameter silicon wafer which is currently most frequently used. Therefore, in order to form a discharge chamber having a prescribed height as in the above-described conventional inkjet head, most of the silicon wafer is scraped and wasted and discarded, making it difficult to obtain a low-cost head. Become.

The present invention has been made in view of the above problems, and has as its object to reduce the cost of a droplet discharge head.

[0008]

In order to solve the above-mentioned problems, a method of manufacturing a droplet discharge head according to the present invention is directed to a method of manufacturing a droplet discharge head in which electrodes are provided on both surfaces of a first substrate forming a discharge chamber and a diaphragm. After laminating and joining the substrates, the first substrate is cut and divided along a plane perpendicular to the laminating direction.

Here, the first and second substrates are both silicon wafers, a first substrate having a high-concentration impurity layer formed on both surfaces, an oxide film formed on the bonding surface side, and a concave portion formed in the oxide film. And the second substrate having an electrode formed on the bottom surface of the concave portion is preferably bonded by direct bonding of silicon.

Further, the first substrate is a silicon wafer,
The second substrate is made of borosilicate glass and has a high-concentration impurity layer formed on both surfaces, and a concave portion is formed on the bonding surface side, and a second substrate having an electrode formed on the bottom surface of the concave portion is bonded by anodic bonding. Is preferred.

In each of the methods for manufacturing a droplet discharge head according to the present invention, it is preferable that the cut surface of the divided first substrate is ground to a thickness of 100 μm or less by plane grinding and mirror polishing. . Further, after the first substrate and the second substrate are joined, it is preferable to grind the outer diameter of the first substrate to be smaller than the outer diameter of the second substrate. In this case, it is preferable to form a guide groove for guiding the cutting blade on the outer periphery of the first substrate.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an exploded perspective view of an electrostatic ink jet head to which the present invention is applied, FIG. 2 is a top view illustrating the head in a transparent state, FIG. FIG. 4 is an enlarged sectional view of a main part of the head in the lateral direction of the diaphragm.

This ink jet head includes a flow path substrate 1 formed from a first substrate described later, an electrode substrate 3 formed from a second substrate described below provided below the flow path substrate 1, This is a laminated structure in which a nozzle plate 4 provided on the upper side is overlapped and joined, whereby a plurality of nozzles 5, a discharge chamber 6 which is an ink flow path communicating with each nozzle 5, and a fluid resistance portion 7 To form a common liquid chamber 8 and the like that communicate with each other.

The flow path substrate 1 is made of a single crystal silicon substrate, and includes a discharge chamber (liquid chamber) 6, a vibration plate 10 that forms the bottom surface of the discharge chamber 6, and a recess that forms a partition 11 between the discharge chambers 6. A recess forming the common liquid chamber 8 is formed. The flow path substrate 1 has a thickness (depth) that becomes a diaphragm on a silicon substrate.
Then, anisotropic etching is performed using the high-concentration boron diffusion layer as an etching stop layer to form a high-concentration boron diffusion layer when forming a recess or the like serving as the discharge chamber 6. The diaphragm 5 having a desired thickness is obtained by performing a predetermined process while leaving it.

As the electrode substrate 3, a single crystal silicon substrate is used, and an oxide film 3 is formed by wet or dry thermal oxidation.
a, and an electrode forming groove (recess) 14 is formed in the oxide film 3a.
Is formed on the bottom surface of the concave portion 14, an electrode 15 facing the diaphragm 10 is provided, a gap 16 is formed between the diaphragm 10 and the electrode 15, and the actuator portion ( Energy generating means).

The diaphragm 1 is provided on the electrode 15 of the electrode substrate 3.
An insulating layer 17 such as a silicon oxide film (SiO ₂ ) is formed to prevent the electrode 15 from being damaged by contact with zero. The electrode 15 extends to near the end of the electrode substrate 3 to form an electrode pad portion 15a for connecting to an external drive circuit via a connection means.

The electrode 15 of the electrode substrate 3 may be made of gold, a metal material such as Al, Cr, Ni or the like generally used in a process of forming a semiconductor element, Ti, TiN, W
And the like can be used. The electrode substrate 3 and the flow path substrate 1 are joined by direct joining of silicon.

A large number of nozzles 5 are formed in the nozzle plate 4 using a silicon substrate, and a groove for forming a fluid resistance portion 7 for communicating the common liquid chamber 8 and the discharge chamber 6 is formed. The flow path substrate 1 The nozzle plate 4 and the flow path substrate 1 are directly bonded to each other via protective films 1a and 4a having an ink contact resistance formed on inner surfaces of the respective nozzle surfaces.

In the ink jet head configured as described above, the diaphragm 10 is used as a common electrode, and the electrode 15 is used as an individual electrode. An electrostatic force (electrostatic attraction force) is generated between the electrode 15 and the electrode 15, and the diaphragm 10
Deforms and displaces to the 5th side As a result, the internal volume of the discharge chamber 6 is expanded and the internal pressure is reduced, so that the ink is filled from the common liquid chamber 8 into the discharge chamber 6 via the fluid resistance portion 7.

Next, when the voltage application to the electrode 15 is stopped,
The electrostatic force stops working, and the diaphragm 10 is restored by its own elasticity. With this operation, the internal pressure of the ejection chamber 6 increases, and ink droplets are ejected from the nozzles 5. When a voltage is applied to the electrode 15 again, the diaphragm 10 is drawn toward the electrode 15 again by the electrostatic attraction force.

Next, a first embodiment of the method for manufacturing an ink jet head according to the present invention will be described with reference to FIGS. FIGS. 5 to 7 are schematic explanatory views in the transverse direction of the diaphragm for explaining the manufacturing process, FIGS. 8 to 10 are schematic explanatory views in the longitudinal direction of the diaphragm, and FIGS.
FIG. 4 is an explanatory view illustrating a substrate cutting step.

First, as shown in FIGS. 5A and 8A, the second substrate 23 for forming the electrode substrate 3 is made of p-type single crystal silicon which is commercially available as a low-resistance product. Using a silicon wafer having a plane orientation of (110) or (100), a silicon oxide film 23 serving as a protective film is formed on the second substrate 23 by a wet or dry thermal oxidation method.
a is formed to a thickness of about 2 μm.

The thickness of the oxide film 23a may be any thickness as long as electrical insulation between the electrode 15 and the silicon wafer is ensured, and is suitably about 1 to 3 μm. Here, as the second substrate 23, a p-type single crystal silicon substrate commercially available at low cost is used, but an n-type silicon substrate may be used.

Subsequently, a photoresist is applied on the second substrate 23, and patterning is performed to form the electrode 15. Using this photoresist pattern as a mask, a hydrogen fluoride solution containing a buffer component such as ammonium fluoride is used. (For example, BHF-63U manufactured by Daikin Industries, Ltd.), etching (digging) is performed, and as shown in FIGS. 5B and 8B, a recess is formed in the silicon oxide film 23a. 1
4 is formed.

At this time, the depth of the recess 14 is determined by adding the thickness of the electrode material and the amount of space (gap length) required between the electrode 15 (actually, the insulating layer 17) and the diaphragm 10. You will dig into it. The digging amount here is about 1μm
Since it is as small as not more than the extent, even when digging by wet etching using a hydrogen fluoride solution, variation in the digging amount in the wafer surface can be extremely reduced.

Further, a polycrystalline silicon film serving as an electrode material is deposited to a thickness of about 300 nm,
As shown in (c), the electrode 15 is formed by processing it into a desired electrode shape using a photoetching technique.
Here, polysilicon doped with impurities is used for the electrode 15, but a high melting point metal may be used.
A conductive ceramic such as titanium nitride may be used as the electrode 15. Thereafter, as shown in FIG. 5D and FIG. 8D, an insulating film for protecting the electrode 15 is formed and then patterned to form an insulating layer 17 on the surface of the electrode 15.
To form

Next, as shown in FIGS. 7A and 9A, the first substrate 21 serving as the flow path substrate 1 for forming the discharge chamber 6 and the diaphragm 10 has p-type polarity. , (11
Using a silicon wafer polished on both sides having a crystal plane orientation of 0), a high-concentration boron diffusion layer 25 was formed on both surfaces of the first substrate 21 which are to be bonded. Here, the first substrate 2
After implanting high-concentration boron (concentration of 5 × 10 ¹⁹ atoms / cm ³ or more) into 1, it is activated and diffused to the depth of the diaphragm 10.

As a method for implanting boron as an impurity, a solid diffusion method using boron glass is used, but boron may be implanted and diffused by an ion implantation method, an impurity glass coating method, or the like. . Alternatively, a substrate obtained by epitaxially growing silicon on a high-concentration impurity substrate (high-concentration boron diffusion layer) may be used.

Next, both surfaces of the first substrate 21 in which the impurities are diffused are mirror-polished by a method such as CMP (chemical-mechanical-polishing), and the surface roughness is processed to an Ra value of 0.2 nm or less. This is to correct that the surface of the silicon wafer is roughened by impurity implantation diffusion, and the polishing amount may be about 0.01 μm. This polishing amount is exactly the same as that of the final polishing and finishing method of the silicon wafer, and the polishing can be performed with very high precision.

Subsequently, the two second substrates 23, 23 on which the electrodes 15 and the like are formed, and the first substrate 21 are each cleaned by a substrate cleaning method such as RCA cleaning, and then the sulfuric acid and the hydrogen peroxide solution are heated. The surface is immersed in the mixed solution to make the bonding surface hydrophilic so that the surface can be directly bonded. And the first substrate 2
A second substrate 2 having electrodes 15 and the like formed on both surfaces of the substrate 1
3 and 23 are joined. At this time, these second substrates 2
Positioning and joining are performed by using an orientation flat portion on the third and third substrates 23 and the first substrate 23 or by preparing an alignment mark in advance.

Then, the first substrate 21 and the second substrates 23, 23 after the completion of the alignment are introduced into a vacuum chamber, and the pressure is reduced until the degree of vacuum becomes 1 × 10 ⁻³ mbar or less. Subsequently, the pre-joining was completed by pressing down the first substrate 21 and the second substrates 23, 23 in a state where the alignment of the first substrate 21 and the second substrates 23, 23 did not shift. At this time, it is important that the substrate be pressed so as not to be displaced, and that the pressing force be strongly suppressed unless the substrate is distorted or displaced.

Next, the bonded first substrate 21 and the second substrates 23, 23 are heated at 900.degree.
By sintering for a time, as shown in FIG. 11A, a joining member 26 in which the first substrate 21 and the second substrates 23 are firmly joined is obtained. The firing temperature at this time is 800
Within a temperature range of 温度 1230 ° C., it is possible to obtain sufficient strength to withstand the subsequent cutting and polishing step. In this temperature range, it is possible to select and carry out the type of electrode material and the temperature at which re-diffusion of impurities does not occur.

Next, after cooling the joining member 26, FIG.
A guide groove 29 for guiding the cutting blade is formed on the outer peripheral surface of the first substrate 21 using a diamond tool 28 having a wedge-shaped cross section as shown in FIG. Using a diamond blade wheel 30, which is a cutting blade as shown in FIG. 3C, the first substrate 21 is moved in a direction along a plane perpendicular to the thickness direction of the first substrate 21, that is, in a direction parallel to the bonding surface. 21 is cut (the first substrate 21 after cutting is referred to as “first substrate half 31”).

As a result, as shown in FIG. 3D, two members 27 in which the first substrate half 31 is joined to the second substrate 23 are obtained at the same time. In addition, although the diamond inner peripheral blade wheel 30 was used for cutting the first substrate 21, a cutting means such as a wire saw can be used.

As described above, the second substrate 23 provided with electrodes on both surfaces of the first substrate 21 forming the discharge chamber 6 and the diaphragm 10
After laminating and joining, the first substrate 21 is cut along the plane perpendicular to the laminating direction and divided, whereby the thickness of the first substrate 21 is halved, and the first substrate 21 is cut in a later grinding / polishing process. Cost can be reduced and cost can be reduced.

Before cutting the first substrate 21 with a cutting blade such as a diamond blade wheel 30, the outer periphery of the first substrate 21 is made smaller than the outer diameter of the second substrate 23 using a diamond tool 28 or the like in advance. By grinding, it is possible to prevent a decrease in cutting accuracy due to the movement of the cutting blade during cutting. Moreover, in this case, the outer circumference of the first substrate 21 is made smaller than the outer diameter of the second substrate 23, and the guide groove 29 for guiding the diamond blade wheel 30 is formed. Runout is further reduced and cutting accuracy is improved.

Referring back to FIGS. 6B and 9B, the first substrate half 31 is placed on the second substrate 23 obtained as described above.
Is cut from the cut surface of the first substrate half 31 to reduce the thickness of the first substrate half 31 to about 100 μm. Even if the thickness of the wafer is reduced by such a mechanical, physical or chemical method, the directly bonded interface is not separated or broken.

Specifically, there was no problem even if the discharge chamber 6 was processed after the first substrate half 31 was polished with a liquid chamber height of 95 ± 5 μm. The height of the liquid chamber at this time is determined in consideration of the amount acting as the fluid resistance due to the reduced liquid chamber and the influence of crosstalk between adjacent bits. Since this is determined by the viscosity of the ink to be used, the amount of ink droplets to be ejected, and the like, it cannot be uniquely determined. In an experiment using a dye ink, good characteristics could be obtained at a liquid chamber height of 50 to 100 μm, particularly around 90 μm.

Subsequently, the first substrate half body 31 is heat-treated to form a buffer oxide film on the surface to a thickness of about 50 nm, and a silicon nitride film to be an etching barrier layer in a later step is formed by a method such as CVD. To a thickness of about 100 nm. Then, a photoresist film is formed on the silicon nitride film, and the discharge chamber 6 is formed by using a photo-etching technique.
A mask for a photoresist film was formed by performing patterning for forming a film. The pattern of the electrode 15 on the second substrate 23 was positioned with respect to the mask using an infrared alignment method or the like.

Next, using the mask of the photoresist film on the first substrate half 31, the silicon nitride film and the silicon oxide film described above are sequentially etched to form the discharge chamber 6 formed of the silicon nitride film and the silicon oxide film. A mask to be formed is formed. It is necessary to prepare a photomask suitable for each crystal plane orientation of the divided wafer (first substrate half 31) in relation to the crystal direction. However, it is only necessary to convert the basic pattern into a target shape, and there is no need to newly design. Further, if the mask cost is also reflected in the production amount, the cost hardly increases.

Next, the first substrate half 31 to which the second substrate 23 is bonded is placed in a high-concentration potassium hydroxide solution (for example, 8
(30% KOH solution heated to 0 ° C.) and anisotropically etching the silicon, as shown in FIGS. 7A and 10A, the discharge chamber 6 and the common liquid chamber. 7 and the electrode pad portion 15a are formed. At this time, when the etching solution reaches the high-concentration boron diffusion layer 25, the etching rate is remarkably reduced, so that the etching is stopped almost automatically.
Is formed.

Although the etching is performed using a high-concentration aqueous solution of an alkali metal, wet etching using TMAH (tetramethylammonium hydroxide) may be used. Then, after rinsing (time about 10 minutes) using ultrapure water, it is dried by spin drying or the like. continue,
An ink-resistant film 1a was deposited on the surface of the first substrate half 31.

Thereafter, as shown in FIGS. 8 (b) and 10 (b), the nozzle plate 4 made of a silicon substrate is bonded on the first substrate half 31, and the surface of the nozzle plate 4 is subjected to a water-repellent treatment. To obtain a desired ink jet head by cutting out each head size.

This ink jet head has a second substrate 2
Since the third substrate 21 and the first substrate 21 are both silicon wafers and are bonded by direct bonding of silicon, there is no difference in thermal expansion between the second substrate 23 and the first substrate 21 and the head manufacturing process There is no distortion due to the thermal history of the substrate, and no substrate distortion or the like due to a temperature change in use is generated, so that the printing characteristics are stable and a highly reliable head can be obtained, and a long head called a line head (for example,
(A4 size head).

Next, another example of the first substrate cutting step in this manufacturing step will be described with reference to FIG. In this example, a diamond tool 40 having a semicircular cross section is used as a tip as shown in FIG. 7A, and a semicircular cross section is formed on the outer peripheral surface of the first substrate 21 as shown in FIG. The guide groove 41 is formed by grinding.

As described above, before cutting the first substrate 21 with a cutting tool such as a diamond inner peripheral blade wheel, the outer diameter of the first substrate 21 is ground to be smaller than the outer diameter of the second substrate 23, and the diamond is further cut. By forming a guide groove for guiding the inner peripheral wheel, the diamond inner peripheral wheel 30 is formed.
As described above, it is possible to improve the cutting accuracy by reducing the runout when using.

Further, the outer diameter of the first substrate 21 is
By grinding smaller than the outer shape of the first substrate 2, the first substrate 2
The step between the first substrate 24 and the second substrate 24 can be eliminated, and the residue of polishing powder and the like can be prevented.

That is, the first substrate 21 shown in FIG.
As shown in an enlarged manner, the ends of the silicon wafers forming the second substrates 23, 23 have a step (unevenness) between the first substrate 21 and the second substrates 23, 23 when these substrates are joined. However, when the outer periphery of the first substrate 21 is ground as shown in FIG.
The first substrate 21 and the second substrate 21 are also ground by partially grinding
There is no step between the substrates 23 and 23. This allows
Abrasive powder and the like do not remain on the step. Also, by finishing polishing the ground surface to about 1000 count,
It is also possible to return to the semiconductor process again.

Next, still another example of the first substrate cutting step in this manufacturing step will be described with reference to FIG.
Here, as shown in FIG. 3A, three sets of joining members 26 in which the first substrate 21 and the second substrates 23, 23 are joined with the same specifications are stacked, and a multi-blade blade 42 is used to stack the joining members 26.
By cutting three first substrates 21 at a time, six sets of members 37 are formed. In this case, positioning accuracy of the wafer connecting means and the orientation flat is important.

By simultaneously cutting a large number of first substrates by using the multi-blade, the cutting process can be shortened, and the cost of the head can be further reduced.

Next, a method for manufacturing an ink jet head according to a second embodiment of the present invention will be described. This embodiment is the same as the first embodiment except that borosilicate glass is used as the second substrate. Therefore, the illustration is omitted, and the reference numerals are the same as those in the first embodiment. use.

First, a commercially available borosilicate glass (for example, Corning 7740: trade name) is used for the second substrate 23, and a photoresist is applied to the second substrate 23 by a method such as photolithography. Patterning for forming the electrode 15, and using this photoresist pattern as a mask, a hydrogen fluoride solution containing a buffer component such as ammonium fluoride (for example, manufactured by Daikin Industries:
The recess 14 is formed in the second substrate 23 using BHF-63U (trade name).

The digging amount at this time is digging by adding the thickness of the electrode material and the necessary space between the electrode 15 (actually, the insulating layer 17) and the diaphragm 10.
Since the digging amount at this time is as small as about 1 μm or less, the digging in the wafer surface can be performed even with a glass substrate having isotropic etching characteristics or with digging by wet etching using a hydrogen fluoride solution. The variation in the embedding amount can be extremely small.

Next, nickel as an electrode material is deposited on the entire surface of the second substrate 23 by a sputtering method, a photoresist is formed, and patterning for forming an electrode is performed by using a photo-etching technique. An electrode 15 having a desired shape was formed by forming a photoresist pattern and using the mask as a mask to etch nickel.

Next, second substrates 23, 23 made of a glass substrate were bonded to both surfaces of the first substrate 21 by anodic bonding. Specifically, each of the substrates 23, 23 is cleaned using a substrate cleaning method known as RCA cleaning, and the bonding surface is made hydrophilic so as to make the surface state easy for anodic bonding. Then, the second substrates 23 on which the electrodes 15 are formed are aligned on both surfaces of the first substrate 21 by utilizing the orientation flat of the first substrate 21 or the like.

After heating to about 400 ° C. in a nitrogen gas atmosphere, the silicon wafer of the first substrate 21 is grounded,
A voltage of 350 to 500 V as a relative potential is applied to the second substrates 23, 23, and three substrates (one first substrate 21 and two second substrates 23, 23) are simultaneously bonded by anodic bonding. Thus, the joining member 26 is obtained. This bonding can be easily performed using a commercially available anodic bonding apparatus (for example, EV Series (trade name) manufactured by Electric Visions Co., Ltd.).

Then, after the joining member 26 is cooled and taken out, the first substrate 21 is cut in the same manner as in the first embodiment, and the member 27 in which the first substrate half 31 is joined to the second substrate 23 is cut. Are formed, and the first substrate half 31 is etched to form the discharge chamber 6, the vibration plate 10, and the like.

By using a glass substrate as the second substrate in this manner, cost reduction can be achieved.

Next, a third embodiment of the present invention will be described. This embodiment is different from the first embodiment only in the substrate cutting process, and is not shown. In this embodiment, the first substrate 21 is directly cut by the diamond inner peripheral blade wheel 30 without forming the guide groove 28 as in the first embodiment.

In this case, the diamond inner peripheral wheel 3
The blade thickness of 0 is defined by the diameter of the wafer (first substrate 21) to be cut and the cutting speed at the time of cutting.
Using a wafer with a diameter of 150 mm and a thickness of 625 μm, the cutting feed rate is 50 mm / min, and the thickness of the blade is 3
The thing of 00 μm was used.

At this time, the shaving allowance of the first substrate 21 is about 323 μm due to the deviation of the wheel 30 and the like, and the diameter of the first substrate 21 is 1 mm.
In the first substrate 21 having a thickness of 50 mm and a thickness of 625 μm, the thickness of the first substrate half 31 became about 150 μm after cutting. Although the silicon surface has an inherent strain in the cut surface, its thickness is about 30 μm, and polishing to a thickness of about 100 μm with a liquid chamber height requires an appropriate amount of polishing allowance (polishing mirror surface finishing amount).
Will remain.

Therefore, the cut surface of the first substrate half 31 was polished by the CMP method. With current CMP technology,
Polishing variation of 0.008 with a polishing amount of about 0.01 μm
It can be finished to about μm, and a very good plane can be obtained on the second substrate. The surface roughness is Ra value,
An extremely smooth surface of 0.1 to 0.2 nm can be obtained. As a result, the accuracy of photolithography for forming the discharge chamber 6 can be improved, and the subsequent anisotropic etching does not cause poor etching due to dripping of crystals.

In the above embodiments, the present invention is applied to a method of manufacturing an ink jet head. However, the present invention can be similarly applied to a method of manufacturing another droplet discharge head, for example, a head for discharging a liquid resist or the like.

[0064]

As described above, according to the droplet discharge head of the present invention, the second substrate provided with electrodes on both surfaces of the first substrate forming the discharge chamber and the diaphragm is laminated and joined. Thereafter, by cutting and dividing the first substrate along a plane perpendicular to the laminating direction, it is possible to reduce the amount of shaving of the first substrate and obtain a highly reliable head at low cost. .

Here, the first and second substrates are both silicon wafers, a first substrate having a high-concentration impurity layer formed on both surfaces, an oxide film formed on the bonding surface side, and a concave portion formed in the oxide film. Is formed, and the second substrate having the electrode formed on the bottom surface of the concave portion is bonded by direct bonding of silicon,
There is no difference in thermal expansion between the first and second substrates, no distortion due to heat history in the head manufacturing process, and even when a high-density line head (long head) is manufactured, it is affected by temperature changes during use. Since the substrate distortion does not occur, the printing characteristics are stable, and a highly reliable head can be obtained.

Further, the first substrate is a silicon wafer,
The second substrate is made of borosilicate glass and has a high-concentration impurity layer formed on both surfaces, and a concave portion is formed on the bonding surface side, and a second substrate having an electrode formed on the bottom surface of the concave portion is bonded by anodic bonding. By doing so, cost reduction can be achieved.

Further, by cutting the cut surface of the first substrate after the division into a layer having a thickness of 100 μm or less by surface grinding and mirror polishing, a minute discharge chamber can be formed, and The etching time can be shortened, and the slope area generated due to the plane orientation during anisotropic etching can be reduced due to the low discharge chamber height.

After the first substrate and the second substrate are joined, the outer diameter of the first substrate is ground to be smaller than the outer diameter of the second substrate, thereby using a cutting tool such as a diamond inner peripheral wheel. It is possible to reduce runout and improve cutting accuracy.

Further, by forming a guide groove for guiding the cutting blade on the outer periphery of the first substrate, it is possible to surely reduce the deviation caused by the use of the cutting tool, and the cutting precision is further improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an electrostatic inkjet head to which the present invention is applied.

FIG. 2 is an explanatory top view showing the transmission state of the head.

FIG. 3 is a schematic cross-sectional explanatory view of the head in the longitudinal direction of the diaphragm.

FIG. 4 is an enlarged schematic cross-sectional view of a main part of the head in the transverse direction of the diaphragm.

FIG. 5 is an explanatory view in a lateral direction of a diaphragm for explaining a manufacturing process of the head according to the first embodiment of the present invention.

FIG. 6 is an explanatory view in the transverse direction of the diaphragm for explaining the manufacturing process.

FIG. 7 is an explanatory view in the lateral direction of the diaphragm for explaining the manufacturing process.

FIG. 8 is an explanatory view in the longitudinal direction of the diaphragm for explaining the manufacturing process.

FIG. 9 is an explanatory view in the longitudinal direction of the diaphragm for explaining the manufacturing process.

FIG. 10 is an explanatory view in the longitudinal direction of the diaphragm for explaining the manufacturing process.

FIG. 11 is an explanatory view illustrating a first substrate cutting step of the manufacturing process.

FIG. 12 is an explanatory view illustrating another example of the first substrate cutting step of the manufacturing process.

FIG. 13 is an explanatory diagram for explaining the operation of the first substrate cutting step;

FIG. 14 is an explanatory view illustrating still another example of the first substrate cutting step of the manufacturing process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Flow path board, 2 ... Electrode board, 3 ... Nozzle plate, 4 ... Nozzle, 6 ... Discharge chamber, 7 ... Fluid resistance part, 8 ... Common discharge chamber, 1
0: diaphragm, 14: recess, 23: second substrate, 23: first substrate, 25: high-concentration boron diffusion layer, 31: first substrate half, 29, 41: guide groove.

Claims (6)

[Claims] A nozzle for discharging droplets, a discharge chamber communicating with the nozzle, a diaphragm forming a wall surface of the discharge chamber, and an electrode opposed to the diaphragm; In the method of manufacturing a droplet discharge head that discharges droplets by deforming in the above, after laminating and joining the second substrate provided with the electrodes on both surfaces of the first substrate forming the discharge chamber and the diaphragm, A method of manufacturing a droplet discharge head, comprising cutting and dividing a first substrate along a plane perpendicular to a lamination direction. 2. The method of manufacturing a droplet discharge head according to claim 1, wherein the first and second substrates are both silicon wafers, and the first substrate has a high concentration impurity layer formed on both surfaces thereof. A droplet discharge, wherein an oxide film is formed on the bonding surface side, a concave portion is formed in the oxide film, and the second substrate having the electrode formed on the bottom surface of the concave portion is bonded by direct bonding of silicon. Head manufacturing method. 3. The method of manufacturing a droplet discharge head according to claim 1, wherein the first substrate is a silicon wafer,
The second substrate is borosilicate glass, the first substrate having a high-concentration impurity layer formed on both surfaces thereof, a concave portion formed on the bonding surface side, and the second substrate having the electrode formed on the bottom surface of the concave portion is formed as an anode. A method for manufacturing a droplet discharge head, comprising joining by joining. 4. The method for manufacturing a droplet discharge head according to claim 1, wherein the cut surface of the divided first substrate is subjected to surface grinding and mirror polishing to a thickness of 100 μm.
m. A method for manufacturing a droplet discharge head, comprising: 5. The method for manufacturing a droplet discharge head according to claim 1, wherein after the first substrate and the second substrate are joined, the outer diameter of the first substrate is changed to the second substrate. A method for manufacturing a droplet discharge head, characterized in that grinding is performed so as to be smaller than the outer shape of the droplet discharge head. 6. The method for manufacturing a droplet discharge head according to claim 1, wherein a guide groove for guiding a cutting blade is formed on an outer periphery of the first substrate. Head manufacturing method.