JP2005053066A - Manufacturing method for nozzle plate, inkjet head, and inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost manufacturing method for a highly precise nozzle plate using a single crystal silicon substrate, and to provide an inkjet head using the nozzle plate manufactured by the manufacturing method, and an inkjet recording device having the inkjet head mounted. <P>SOLUTION: In the method, the nozzle plate 3 with a nozzle hole 11 for discharging a solution is manufactured by carrying out etching to the single crystal silicon substrate 3a. The method includes a process of thinning the single crystal silicon substrate 3a by etching the whole of at least one face of the single crystal silicon substrate 3a which becomes the nozzle plate 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a nozzle plate manufacturing method, an ink jet head, and an ink jet recording apparatus, and in particular, a low cost manufacturing method of a nozzle plate using a single crystal silicon substrate, an ink jet head using a nozzle plate manufactured by the manufacturing method, and The present invention relates to an ink jet recording apparatus equipped with this ink jet head.

  In the conventional nozzle forming method of an injection apparatus, there is a method in which a single crystal silicon substrate is subjected to anisotropic dry etching by ICP discharge or the like to form a nozzle having a stepwise smaller section toward the tip side. (For example, see Patent Document 1).

  Further, in the conventional method for manufacturing a nozzle plate for an ink jet head, a nozzle plate is manufactured by etching a substrate made of a plastic material such as a polyimide sheet instead of a silicon substrate, thereby reducing the cost. (For example, see Patent Document 2).

Japanese Patent Laid-Open No. 11-28820 (page 4, FIGS. 2 and 3) Japanese Patent Laid-Open No. 2002-96472 (first page, FIG. 2)

  In a conventional nozzle forming method of an injection device (see, for example, Patent Document 1), a nozzle plate is manufactured using a silicon substrate having a thickness of 180 μm from the beginning because of the depth of the nozzle and the wiping of the peripheral portion of the nozzle. Therefore, there is a problem that an expensive thin silicon substrate is required and the cost is increased. In addition, since a thin silicon substrate is used, there is a problem that handling is difficult and yield is lowered.

  Further, in the conventional method for manufacturing a nozzle plate for an ink jet head (see, for example, Patent Document 2), a substrate made of a plastic material is used when forming recesses and nozzle holes by etching. There is a problem that irregularities such as pits (dents) are likely to occur and the processing accuracy is poor. In addition, when a silicon substrate is used when bonding the cavity plate and the nozzle plate, a direct bonding method such as direct bonding can be used, whereas an adhesive is used for a substrate made of a plastic material. There was a problem that had to be done.

  The present invention provides a low-cost manufacturing method of a high-precision nozzle plate using a single crystal silicon substrate, an ink jet head using the nozzle plate manufactured by the manufacturing method, and an ink jet recording apparatus equipped with the ink jet head. For the purpose.

A manufacturing method of a nozzle plate according to the present invention is a method of manufacturing a nozzle plate having nozzle holes for discharging a solution by etching a single crystal silicon substrate, and is a method for manufacturing a single crystal silicon substrate to be a nozzle plate. The method includes a step of thinning the single crystal silicon substrate by etching the entire at least one surface.
Manufacturing a nozzle plate using an inexpensive standard specification silicon substrate by having a step of thinning the single crystal silicon substrate by etching the entire surface of at least one surface of the single crystal silicon substrate to be the nozzle plate Thus, a low-cost method for manufacturing a nozzle plate can be realized. In addition, since a single crystal silicon substrate is used, a nozzle plate with high processing accuracy can be manufactured.

In the nozzle plate manufacturing method according to the present invention, the plane orientation of the single crystal silicon substrate to be the nozzle plate is a (100) orientation.
If a nozzle plate is manufactured using a single crystal silicon substrate having a plane orientation of (100), generation of pits and micropyramids during wet etching can be suppressed, and a highly accurate nozzle plate is manufactured. be able to.

In the nozzle plate manufacturing method according to the present invention, in the step of thinning the single crystal silicon substrate, an etching mask made of a silicon oxide film or a silicon nitride film is formed on one surface of the single crystal silicon substrate. Is.
In the process of thinning the single crystal silicon substrate by etching, surface roughness occurs on the surface to be etched, but an etching mask is formed on one surface of the single crystal silicon substrate to prevent the etching, and the cavity of the nozzle plate It is possible to prevent surface roughness from occurring on the surface to be joined to the plate.

In the nozzle plate manufacturing method according to the present invention, the etching mask is formed by a CVD apparatus.
When forming an etching mask, the etching mask can be formed by thermal oxidation, but since a thermal oxide film is formed on both sides of the single crystal silicon substrate, a process of removing the thermal oxide film on one side is necessary. Become. When this etching mask is formed by a CVD apparatus, the etching mask can be selectively formed on one surface, and thus the manufacturing process can be simplified.

Further, the nozzle plate manufacturing method according to the present invention provides a predetermined area when the area of the single crystal silicon substrate is reduced after the step in the step of thinning the single crystal silicon substrate. A single crystal silicon substrate having an area larger than the area is used.
In the step of thinning the single crystal silicon substrate by wet etching, not only the thickness of the single crystal silicon substrate is reduced, but also the outer peripheral portion (side surface) of the single crystal silicon substrate is etched, so that the area is reduced. Since the degree of reduction of the area of the single crystal silicon substrate can be predicted in advance, a single crystal silicon substrate having an area larger than the predetermined area is selected so that the predetermined area is obtained after the step of thinning the single crystal silicon substrate by etching. It is what you use. In this manner, a single crystal silicon substrate having a desired area can be obtained after the step of thinning the single crystal silicon substrate. Further, when performing anisotropic dry etching by ICP discharge described later, the adsorption surface is not exposed, and it is possible to prevent the adsorption surface from being etched and normal adsorption cannot be performed.

In the nozzle plate manufacturing method according to the present invention, the step of thinning the single crystal silicon substrate is wet etching with a 20 wt% to 30 wt% potassium hydroxide aqueous solution.
When etching is performed with an aqueous potassium hydroxide solution of 20% by weight or less, many pits (dents) are generated on the etched surface, and the pits become larger as the concentration becomes lower. Further, when etching is performed with an aqueous potassium hydroxide solution of 30% by weight or more, the outer peripheral portion (side surface) of the single crystal silicon substrate is etched in a saw shape, which causes cracks and scratches on the single crystal silicon substrate. Therefore, wet etching is performed with a 20 wt% to 30 wt% aqueous potassium hydroxide solution that has the least of these problems.

In the nozzle plate manufacturing method according to the present invention, the step of thinning the single crystal silicon substrate is wet etching using a 10 wt% to 30 wt% potassium hydroxide aqueous solution to which 10 wt% or more ethanol is added. Is.
When an ethanol-added solution is used for etching with an aqueous potassium hydroxide solution, the plane orientation dependency of the etching rate is changed, and generation of pits on the etched surface can be suppressed. However, since pits are generated with 10% by weight or less of ethanol, wet etching is performed with a 10% to 30% by weight potassium hydroxide aqueous solution to which 10% by weight or more of ethanol is added. In addition, the upper limit of the addition amount of ethanol is to the solubility of ethanol of potassium hydroxide aqueous solution.

In the nozzle plate manufacturing method according to the present invention, the step of thinning the single crystal silicon substrate is wet etching with a tetramethylammonium hydroxide aqueous solution.
If wet etching with a tetramethylammonium hydroxide (TMAH) aqueous solution is performed, surface roughness of the surface to be etched can be suppressed as in the case of a 20 wt% to 30 wt% potassium hydroxide aqueous solution.

In the nozzle plate manufacturing method according to the present invention, the nozzle holes are formed by anisotropic dry etching using ICP discharge.
According to anisotropic dry etching by ICP discharge, a relatively deep nozzle hole can be formed with high anisotropy, so that a nozzle hole with high accuracy can be formed.

In the nozzle plate manufacturing method according to the present invention, the nozzle hole includes the first groove and the second groove, and the area of the cross section of the first groove is smaller than the area of the cross section of the second groove. It is a staircase.
By forming the nozzle holes in a staircase pattern in which the area of the cross section of the first groove is smaller than the area of the cross section of the second groove, it is possible to increase the straightness during droplet discharge.

An ink jet head according to the present invention uses a nozzle plate manufactured by any one of the above-described nozzle plate manufacturing methods.
Since this inkjet head uses a nozzle plate manufactured by a low-cost nozzle plate manufacturing method, the manufacturing cost can be reduced. In addition, since a single crystal silicon substrate is used for the nozzle plate, the inkjet head has high ejection accuracy.

An ink jet recording apparatus according to the present invention is equipped with the above ink jet head.
Since the above-described ink jet head is mounted, the ink jet recording apparatus is low in cost and high in discharge accuracy.

Embodiment 1. FIG.
FIG. 1 is an exploded perspective view of an inkjet head according to Embodiment 1 of the present invention, and FIG. 2 is a longitudinal sectional view of the right half of the inkjet head. FIG. 1 shows a part in a cross section. In the first embodiment, a face inkjet head that ejects droplets of ink or the like from the upper surface side of the substrate is shown. As shown in FIG. 1, the inkjet head according to the first embodiment has a laminated structure in which a cavity plate 1, an electrode substrate 2 and a nozzle plate 3 are stacked and joined. The cavity plate 1 is composed of an electrode substrate 2 and a nozzle plate. 3 between.

  The cavity plate 1 is made of a single crystal silicon substrate, and has a recess 5a whose bottom surface becomes the vibration plate 4. The discharge chamber 5 (see FIG. 2) is formed by joining the nozzle plate 3 on the recess 5a. Further, the cavity plate 1 has a recess 6a for forming a common reservoir 6 for supplying droplets to the respective discharge chambers 5. The cavity plate 1 and the nozzle plate 3 are joined together so that the common reservoir 6 is formed. It is formed. A TEOS film (tetraethylorthosilicate film, not shown) is formed on the entire surface of the cavity plate 1 by plasma CVD (plasma chemical vapor deposition), for example, to have an insulating film of 0.1 μm. The TEOS film is for preventing dielectric breakdown and short-circuit when driving the inkjet head, and for preventing the cavity plate 1 from being etched by droplets of ink or the like.

The electrode substrate 2 is made of borosilicate glass, and a recess 8 for mounting the electrode 7 is formed on the upper surface of the electrode substrate 2. The recess 8 is for providing a gap G (gap) between the electrode 7 and the diaphragm 4 (see FIG. 2), and is formed to face the diaphragm 4. The concave portion 8 is formed so that the electrode 7, the lead portion 9, and the terminal portion 10 can be attached therein, and the portion where the electrode 7 is attached is patterned in a slightly larger shape than the electrode 7. The electrode 7 is formed by sputtering an ITO film (indium tin oxide film) inside the recess 8 of the electrode substrate 2.
Here, for example, if the recess 8 is etched to a depth of 0.3 μm and the ITO film of the electrode 7 is formed to a thickness of 0.1 μm, the gap G is 0.2 μm.
The electrode substrate 2 may be formed of a silicon substrate or the like instead of borosilicate glass.

The nozzle plate 3 is made of, for example, a single crystal silicon substrate having a thickness of 180 μm, and the nozzle holes 11 penetrating in the thickness direction of the nozzle plate 3 are formed. In the nozzle hole 11, the lower surface side of the nozzle plate 3 communicates with the discharge chamber 5, and the upper surface side of the nozzle plate 3 is an opening for discharging droplets. The nozzle hole 11 has a first groove 11a having a small cross-sectional area on the upper surface side of the nozzle plate 3 and a second groove 11b having a large cross-sectional area on the lower surface side of the nozzle plate 3, and has a stepped shape. This is a two-stage nozzle. On the lower surface of the nozzle plate 3, there are provided a recess 12 a serving as an orifice 12 for communicating the discharge chamber 5 and the common reservoir 6, and a recess 13 a (see FIG. 2) for providing the reservoir diaphragm 13. A portion corresponding to the reservoir diaphragm 13 on the upper surface of the nozzle plate 3 is a recess. By thinning the reservoir diaphragm 13 in this way, droplets can be stably ejected even when there is a change in the external pressure.
Although FIG. 1 shows an inkjet head in which the nozzle holes 11 and the discharge chambers 5 are arranged in two rows, the nozzle holes 11 and the discharge chambers 5 may be arranged in one row.

The operation of the ink jet head shown in FIGS. 1 and 2 will be described. A voltage of about 30 volts is applied between the electrode 7 and the diaphragm 4 by a transmission circuit (not shown), and the diaphragm 4 is bent toward the electrode 7 by electrostatic force. Next, when the applied voltage is removed, the flexed diaphragm 4 is restored to its original state. At this time, since the pressure inside the discharge chamber 5 rises rapidly, droplets are discharged from the nozzle holes 11. When a voltage is applied again between the electrode 7 and the diaphragm 4, the diaphragm 4 is deflected toward the electrode 7, and a droplet of ink or the like that has accumulated in the reservoir 6 is supplied into the discharge chamber 5 through the orifice 12. The The voltage is applied to the diaphragm 4 through an oxide film window 15 formed in a part of the cavity substrate 1. The supply of droplets to the reservoir 6 is performed through an ink supply hole 14 penetrating the electrode substrate 2 and an ink supply hole 14 a provided in the bottom surface of the reservoir 6.
In the first embodiment, an electrostatic drive type inkjet head that discharges droplets by deflecting the diaphragm 4 by electrostatic force is shown. However, a nozzle plate obtained by a nozzle plate manufacturing method described later is used. Can also be used for a piezoelectric drive type ink jet head.

  The diaphragm 4 of the ink jet head shown in the first embodiment is made of a high-concentration boron-doped layer except for the insulating film portion. In the etching of a silicon substrate with an alkaline aqueous solution, the etching rate becomes very low in a region where boron is doped at a high concentration. For this reason, in the first embodiment, the vibration plate 4 is made of a high-concentration boron-doped layer, and the anisotropic etching of the cavity plate 1 with an alkaline aqueous solution is performed when the concave portion 5a serving as the discharge chamber 5 is formed. The diaphragm 4 having a desired thickness is obtained by stopping at the portion.

3 and 4 are longitudinal sectional views showing manufacturing steps of the nozzle plate 3 of the ink jet head shown in FIGS. 3 and 4 show the right half of the nozzle plate 3 shown in FIG.
First, a single crystal silicon substrate 3a having a thickness of 525 μm and a plane orientation of (100) orientation is prepared (FIG. 3A). Note that the thickness of the single crystal silicon substrate is not limited to 525 μm, but an inexpensive single crystal silicon substrate having such a thickness may be prepared. Further, since the area of the single crystal silicon substrate 3a is reduced in the process of reducing the thickness of the single crystal silicon substrate 3a of FIG. 3D shown below, the area is reduced to a predetermined area after the process of FIG. 3D. Thus, a silicon substrate having an area larger than the predetermined area is used. For example, when it is known in advance that the diameter is reduced by 2 mm from the outer peripheral portion (side surface) of the single crystal silicon substrate 3a, a single crystal silicon substrate 3a having a diameter of 2 mm and a large area is prepared.

Next, thermal oxidation treatment is performed on the single crystal silicon substrate 3a in an oxygen atmosphere containing water vapor to form a silicon oxide film having a thickness of about 1.8 μm on the front surface and the back surface (FIG. 3B). This thermal oxidation treatment is performed at a temperature of 1075 ° C. for about 8 hours.
Then, a resist is formed on the back surface of the single crystal silicon substrate 3a, and the single crystal silicon substrate 3a is immersed in a buffered hydrofluoric acid aqueous solution to remove the silicon oxide film on the front surface (FIG. 3C).
In FIG. 3B, a silicon oxide film is formed on the front side surface and the back side surface of the single crystal silicon substrate 3a by thermal oxidation, but the back side surface is formed by a CVD (Chemical Vapor Deposition) apparatus instead of the thermal oxidation treatment. Only a silicon oxide film or a silicon nitride film may be formed. Thus, if a silicon oxide film or a silicon nitride film is formed only on the back side surface by the CVD apparatus, the step of FIG. 3C can be omitted.

Thereafter, the entire front surface from which the silicon oxide film has been removed is etched to thin the single crystal silicon substrate 3a to 180 μm (FIG. 3D). In this step, the silicon oxide film or silicon nitride film formed on the back surface of the single crystal silicon substrate 3a functions as an etching mask. This whole surface etching process is performed by wet etching, and a 20 wt% to 30 wt% potassium hydroxide aqueous solution, a 10 wt% to 30 wt% potassium hydroxide aqueous solution or tetramethyl hydroxide added with 10 wt% or more ethanol. An aqueous ammonium solution is used.
When the entire surface is etched with a potassium hydroxide aqueous solution to which ethanol is not added, a large amount of pits are generated on the surface to be etched at a concentration of 20% by weight or less, and the pits become larger as the concentration is lower. If the concentration is 20% by weight or more, almost no pits on the surface to be etched are generated, but if the concentration is 30% by weight or more, the outer peripheral portion (side surface) of the single crystal silicon substrate 3a is etched in a saw-like shape. It becomes rattling and causes cracks and scratches during handling. For this reason, when performing the whole surface etching using the potassium hydroxide aqueous solution which ethanol is not added, the thing of the density | concentration of 20 weight%-30 weight% is used.

FIG. 5 shows the state of the surface etched by the potassium hydroxide concentration and the ethanol concentration and the outer peripheral portion of the single crystal silicon substrate 3a when the entire surface is etched with a potassium hydroxide aqueous solution to which ethanol is added. FIG. As shown in FIG. 5, in the region where the concentration of potassium hydroxide is 10% by weight or less and the region where the concentration of ethanol is 10% by weight or less, a large amount of pits are generated on the etched surface. Further, in the region where the concentration of potassium hydroxide is 30% by weight or more, the outer peripheral portion of the single crystal silicon substrate 3a is etched in a saw shape to become rattled. For this reason, when performing the whole surface etching using the potassium hydroxide aqueous solution which added ethanol, the 10 weight%-30 weight% potassium hydroxide aqueous solution which added ethanol 10weight% or more is used.
The upper limit of the amount of ethanol added is up to the solubility of ethanol in the potassium hydroxide aqueous solution so that ethanol can be dissolved in the potassium hydroxide aqueous solution.

  3D may be wet etching using an aqueous tetramethylammonium hydroxide (TMAH) solution. In the whole surface etching with tetramethylammonium hydroxide aqueous solution, surface roughness such as pits on the surface to be etched can be suppressed as in the case of 20% by weight to 30% by weight potassium hydroxide aqueous solution. The suppression of the surface roughness is not related to the concentration of tetramethylammonium hydroxide and may be any concentration. However, when the concentration of tetramethylammonium hydroxide is lowered, the etching rate is slowed down and the time required for the etching is increased.

In the step of wet etching with an aqueous potassium hydroxide solution or the like shown in FIG. 3D, the outer peripheral portion of the single crystal silicon substrate 3a is also etched to reduce the area of the single crystal silicon substrate 3a (dotted line in FIG. 3D). 3) Since the single crystal silicon substrate 3a having a large area is used in advance so as to have a predetermined area after the step of FIG. 3D, the single crystal silicon substrate 3a having a desired area can be obtained. As shown in FIG. 4H, the suction surface is exposed during anisotropic dry etching by ICP discharge, and the suction surface is not damaged.
Further, since the single crystal silicon substrate 3a having the (100) orientation is used, surface roughness such as pits and micropyramids on the surface to be etched during the entire surface etching shown in FIG. Can do.
In addition, since an etching mask made of a silicon oxide film or a silicon nitride film is formed on the back surface of the single crystal silicon substrate 3a during the step of FIG. The surface where the nozzle plate 3 and the cavity plate 1 are joined can be kept flat.

After the step of thinning the single crystal silicon substrate 3a in FIG. 3D, the silicon oxide film or silicon nitride film formed on the back surface of the single crystal silicon substrate 3a is removed with a hydrofluoric acid aqueous solution, and the single crystal silicon is again formed. A silicon oxide film having a thickness of 1.8 μm is formed on the front surface and the back surface of the substrate 3a by thermal oxidation (FIG. 3E). This thermal oxidation treatment is also performed for about 8 hours in an oxygen atmosphere containing water vapor at a temperature of 1075 ° C.
Next, the portion 11c corresponding to the first groove 11a of the nozzle hole 11 and the portion 15a for exposing the electrode extraction window 15 and the terminal portion 10 on the back surface of the single crystal silicon substrate 3a are patterned by photolithography, and these are patterned. This part of the silicon oxide film is removed by etching (FIG. 3F). Patterning is performed by applying a resist to a portion (including the front surface of the single crystal silicon substrate 3a) where the silicon oxide film is not removed.
Then, a portion 11d corresponding to the second groove 11b of the nozzle hole 11, a portion 12b corresponding to the orifice 12, and a portion 13b corresponding to the reservoir diaphragm 13 on the back surface of the single crystal silicon substrate 3a are patterned by photolithography, and these are patterned. This part of the silicon oxide film is half-etched (FIG. 3G). Patterning is performed in the same manner as in FIG. 3F, and the silicon oxide film is left with a thickness of 1.0 μm in the half etching.

  FIG. 4 is a longitudinal sectional view showing a continuation of the manufacturing process of the nozzle plate 3 shown in FIG. The back side surface of the single crystal silicon substrate 3a obtained by half-etching the silicon oxide film in FIG. 3G is subjected to anisotropic dry etching by ICP (inductively coupled plasma) discharge and etched to a depth of 22 μm. At this time, the remaining portion (including the half-etched portion) of the silicon oxide film is not etched. Thereafter, the single crystal silicon substrate 3a is etched with a hydrofluoric acid aqueous solution to reduce the thickness of the silicon oxide film remaining in the half-etched portion. At this time, the silicon oxide film is completely removed from the half-etched portion in FIG. 3G, and the silicon oxide film is thinned by the amount etched in the remaining portion. Then, the back side surface is again subjected to anisotropic dry etching by ICP discharge to 55 μm. Thereby, the portion 11c corresponding to the first groove 11a of the nozzle hole 11 and the portion 15a exposing the electrode extraction window 15 and the terminal portion 10 are etched by 77 μm, and correspond to the second groove 11b of the nozzle hole 11. The portion 11d, the portion 12b corresponding to the orifice 12, and the portion 13b corresponding to the reservoir diaphragm 13 are etched by 55 μm. Thereafter, the single crystal silicon substrate 3a is immersed in a hydrofluoric acid aqueous solution, and all remaining silicon oxide films are removed (FIG. 4H).

In the process of FIG. 4H, the first groove 11a and the second groove 11b of the nozzle hole 11 are formed by anisotropic dry etching by ICP discharge, and thus are etched perpendicularly to the single crystal silicon substrate 3a. The nozzle hole 11 with high accuracy can be formed. Further, since the nozzle hole 11 is a two-stage nozzle, the flow of the liquid droplets is adjusted by the second groove 11b, and the straightness at the time of discharging the liquid droplets can be increased.
In the step of FIG. 4 (h), a recess 12a to be the orifice 12 and a recess 13a for providing the reservoir diaphragm 13 are formed from the portion 12b corresponding to the orifice 12 and the portion 13b corresponding to the reservoir diaphragm 13. It becomes.

Thereafter, the single crystal silicon substrate 3a is subjected to thermal oxidation treatment in an oxygen atmosphere containing water vapor to form a silicon oxide film having a thickness of 1.2 μm on the entire surface (FIG. 4 (i)). This thermal oxidation treatment is performed for about 4 hours in an oxygen atmosphere containing water vapor at a temperature of 1075 ° C.
And the part which forms the recessed part 11e for opening the nozzle hole 11 (refer FIG.4 (k)) in the front side surface of the single crystal silicon substrate 3a, and the part which forms the recessed part 13b for forming the reservoir diaphragm 13 (FIG. 4 (k)) and portions for forming electrode notch windows 15 and notches 15b for exposing the terminal portions 10 (see FIG. 4 (k)) are patterned by photolithography, and silicon oxidation of these portions is performed. The film is removed by etching (FIG. 4 (j)). Patterning is performed in the same manner as in FIG.
Next, the single crystal silicon substrate 3a is immersed in a 25 wt% potassium hydroxide aqueous solution, and 103 μm etching is performed from the portion where the silicon oxide film is removed in the step of FIG. 4 (j) (FIG. 4 (k)). In the step of FIG. 4 (k), since the etching proceeds obliquely from the front surface of the single crystal silicon substrate 3a, patterning corresponding to that is performed in the step of FIG. 4 (j). The reason why the recess 11e is formed is to secure the thickness of the single crystal silicon substrate 3a in a portion other than the peripheral portion of the nozzle hole 11,
In the process of FIG. 4H, the first groove 11a and the second groove 11b may be formed deeply so that the recess 11e is not formed. In the step of FIG. 4K, the reservoir diaphragm 13 having a thickness of 22 μm is formed.

Then, the silicon oxide film remaining on the single crystal silicon substrate 3a is removed with a hydrofluoric acid aqueous solution and penetrates through the first groove 11a of the nozzle hole 11 (FIG. 4L). At this time, the silicon oxide film in the portion of the notch 15b for exposing the electrode extraction window 15 and the terminal portion 10 is also removed.
Finally, thermal oxidation is performed on the entire surface of the single crystal silicon substrate 3a in an oxygen atmosphere to form a silicon oxide film having a thickness of 0.1 μm, thereby completing the nozzle plate 3 (FIG. 4 (m)). This thermal oxidation treatment is performed at a temperature of 1000 ° C. for about 3.5 hours. The silicon oxide film is finally formed for the purpose of preventing etching by droplets of ink or the like and water repellent treatment of the side surface of the nozzle hole 11 and its peripheral portion.

In the first embodiment, an inexpensive standard specification silicon substrate is used by having a step of thinning the single crystal silicon substrate by etching the entire at least one surface of the single crystal silicon substrate to be the nozzle plate. A nozzle plate can be manufactured, and a low-cost method for manufacturing a nozzle plate can be realized. In addition, since a single crystal silicon substrate is used, a nozzle plate with high processing accuracy can be manufactured.
Furthermore, since the inkjet head shown in FIGS. 1 and 2 uses the nozzle plate manufactured by the low-cost nozzle plate manufacturing method shown in the first embodiment, the manufacturing cost can be reduced.

Embodiment 2. FIG.
FIG. 6 is a perspective view showing an example of an ink jet recording apparatus equipped with the ink jet head obtained in the first embodiment. The ink jet recording apparatus 100 is a general ink jet printer.
Since the ink jet head obtained in Embodiment 1 is composed only of a chemically stable substance, it can be generally used for discharging droplets that are not alkaline. For example, a color filter for a liquid crystal display can be manufactured. It can be applied to the formation of a light emitting portion of organic EL, the discharge of a biological liquid, and the like.

  Since the ink jet recording apparatus of the second embodiment is equipped with an ink jet head using the nozzle plate 3 obtained by the manufacturing method of the first embodiment, it can be manufactured at low cost and has high ejection accuracy. is there.

1 is an exploded perspective view of an inkjet head according to Embodiment 1 of the present invention. FIG. 2 is a longitudinal sectional view of the right half of the ink jet head of FIG. 1. FIG. 3 is a longitudinal sectional view showing a manufacturing process of the nozzle plate of the first embodiment. FIG. 3 is a longitudinal sectional view showing a manufacturing process of the nozzle plate of the first embodiment. The figure which showed the density | concentration dependence of the state of an etching surface when etching the whole surface with the potassium hydroxide water containing ethanol. 1 is a perspective view showing an example of an ink jet recording apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cavity plate, 2 Electrode board, 3 Nozzle plate, 4 Diaphragm plate, 5 Discharge chamber, 6 Common reservoir, 7 Electrode, 8 Recessed part, 9 Lead part, 10 Terminal part, 11 Nozzle hole, 12 Orifice, 13 Reservoir diaphragm, 14 Ink supply hole, 15 windows.

Claims (12)

A method of manufacturing a nozzle plate having a nozzle hole for discharging a solution by etching a single crystal silicon substrate,
A method of manufacturing a nozzle plate, comprising: a step of thinning the single crystal silicon substrate by etching the entire at least one surface of the single crystal silicon substrate to be the nozzle plate.   The method for manufacturing a nozzle plate according to claim 1, wherein the plane orientation of the single crystal silicon substrate is a (100) orientation.   3. The step of thinning the single crystal silicon substrate, wherein an etching mask made of a silicon oxide film or a silicon nitride film is formed on one surface of the single crystal silicon substrate. Manufacturing method of nozzle plate.   4. The method of manufacturing a nozzle plate according to claim 3, wherein the etching mask is formed by a CVD apparatus.   In the step of thinning the single crystal silicon substrate, a single crystal silicon substrate having an area larger than the predetermined area is used so that a predetermined area is obtained when the area of the single crystal silicon substrate is reduced after the step. The manufacturing method of the nozzle plate in any one of Claims 1-4 characterized by the above-mentioned.   6. The method of manufacturing a nozzle plate according to claim 1, wherein the step of thinning the single crystal silicon substrate is wet etching using a 20 wt% to 30 wt% potassium hydroxide aqueous solution.   6. The step of thinning the single crystal silicon substrate is wet etching with a 10% by weight to 30% by weight potassium hydroxide aqueous solution to which 10% by weight or more of ethanol is added. The manufacturing method of the nozzle plate as described in 2 ..   The method for manufacturing a nozzle plate according to claim 1, wherein the step of thinning the single crystal silicon substrate is wet etching using a tetramethylammonium hydroxide aqueous solution.   The method of manufacturing a nozzle plate according to claim 1, wherein the nozzle holes are formed by anisotropic dry etching using ICP discharge.   The nozzle hole is composed of a first groove and a second groove, and the area of the cross section of the first groove is smaller than the area of the cross section of the second groove, and has a step shape. The method for manufacturing a nozzle plate according to claim 9.   An ink jet head using a nozzle plate manufactured by the method for manufacturing a nozzle plate according to claim 1. An ink jet recording apparatus comprising the ink jet head according to claim 11.

Images