KR100773983B1 - Inkjet head and manufacturing method thereof - Google Patents

Abstract

An ink jet head and a method for manufacturing the same are provided to prevent a nozzle of the ink jet head from being blocked by filtering dust or foreign substances condensed in ink. An ink jet head includes a pressure chamber(10), a filter section(12), and a nozzle section(16). Ink is accommodated in the pressure chamber. The pressure chamber applies a pressure to the ink by reducing the volume thereof. The filter section is connected to a portion of the pressure chamber and includes a plurality of through-holes forming passages for the ink. The nozzle section is connected to the filter section to discharge ink droplets. A membrane is formed on one surface of the pressure chamber. The volume of the pressure chamber is increased or decreased by driving the membrane.

Description

Inkjet head and manufacturing method thereof

1A is a longitudinal sectional view showing the structure of an inkjet head according to a preferred embodiment of the present invention.

1B is a cross-sectional view showing a filter portion of an inkjet head according to a preferred embodiment of the invention.

2 is a flow chart showing a method of manufacturing an inkjet head according to a preferred embodiment of the present invention.

Figure 3a is a flow chart showing a manufacturing method of the upper substrate of the inkjet head according to an embodiment of the present invention.

Figure 3b is a flow chart showing a manufacturing method of the intermediate substrate of the inkjet head according to an embodiment of the present invention.

Figure 3c is a flow chart showing a manufacturing method of the lower substrate of the inkjet head according to an embodiment of the present invention.

Figure 4a is a flow chart showing a manufacturing process of the upper substrate of the inkjet head according to an embodiment of the present invention.

Figure 4b is a flow chart showing a manufacturing process of the intermediate substrate of the ink jet head according to an embodiment of the present invention.

Figure 4c is a flow chart showing a manufacturing process of the lower substrate of the inkjet head according to an embodiment of the present invention.

5 is a flowchart illustrating a manufacturing process of an inkjet head according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

1: silicon substrate 2: upper substrate

3: oxide film 4: intermediate substrate

5: photoresist 6: lower substrate

7: etching resist 10: pressure chamber

11 through hole 12 filter part

14 cone portion 16 nozzle

18: List 20: Reservoir

22: ink inlet 24: piezoelectric body

The present invention relates to an inkjet head and a method of manufacturing the same.

Inkjet printing technology has been used mainly in the office automation (OA) field and has been mainly used in the field of packaging marking and garment printing for industrial purposes. However, inkjet printing technology has been used in the field of functional ink including nano metal particles such as silver and nickel. With the development, the application potential is gradually expanded, and now, it is applied to the formation of circuit patterns of printed circuit boards using functional inks including nano metal particles.

Recently, technology using inkjets has been developed day by day, and in the electronic industry, methods for using inkjets in manufacturing processes such as color filters and printed circuit boards (PCBs) of liquid crystal displays have been widely studied. Unlike office inkjets, in order to use the inkjet method for industrial purposes, all of the nozzles formed in the inkjet head such as 128 or 256 must be operated.

The general structure of an inkjet head includes a pressure chamber for receiving and pressurizing ink, a nozzle connected to a part of the pressure chamber, a restrictor connected to another part of the pressure chamber, and a restrictor. It is connected to the reservoir (reservoir) for storing the ink supplied to the pressure chamber and the ink inlet (inlet) for supplying ink to the reservoir.

The ink supplied through the ink inlet is introduced into the pressure chamber through the reservoir and the restrictor, and the ink pressurized in the pressure chamber is discharged out through the nozzle. On the other hand, an actuator such as a piezoelectric body is coupled to the pressure chamber to change the volume of the pressure chamber so that the ink contained in the pressure chamber can be pressurized.

The nozzles connected to the pressure chamber are formed to have a very small cross-sectional area in order to allow ink droplets to be ejected, and thus the restrictor is also formed to have a small cross-sectional area to correspond to the ink flow resistance by the nozzle. Therefore, in the inkjet head having such a structure, dust or impurities aggregated in the ink are caught in the restrictor or the nozzle portion, which hinders the smooth flow of the ink and eventually causes the ejection of the ink droplets.

In general, a method of using filtered ink by attaching a filter for removing dust or foreign matter in advance to an ink supply unit for supplying ink to the inkjet head is employed, but this is not a perfect method because dust or foreign matter is not completely removed. There is no limit. In addition, the discharge of the entire nozzle may be impossible due to the contaminants generated due to self-aggregation of the ink supplied into the inkjet head.

Unlike office inkjet heads, when an inkjet head is used for industrial purposes, even if only one nozzle is defective, the whole head loses its function. Therefore, it is necessary to prevent the phenomenon of the restrictor or the nozzle in the inkjet head from clogging due to dust or foreign matter aggregated in the ink. That is, in addition to the external filter, a filtering system provided in the head itself is required.

SUMMARY OF THE INVENTION The present invention provides an inkjet head and a method of manufacturing the same for improving a discharge failure of an inkjet head caused by agglomeration of ink or impurities contained in the ink.

According to an aspect of the present invention, a filter portion for accommodating the ink, the pressure chamber for applying pressure to the ink by the reduction of the volume, and a plurality of through-holes connected to a portion of the pressure chamber, forming a flow path of the ink And an inkjet head connected to the filter portion and including a nozzle portion for discharging ink droplets.

A membrane is formed on one surface of the pressure chamber, and the volume of the pressure chamber may be increased or decreased by driving the membrane. It is preferable that the piezoelectric body is bonded to the membrane. It may further include a restrictor connected to the other part of the pressure chamber and forming a flow path through which ink is supplied to the pressure chamber.

The cross-section of the through hole is hexagonal, and the filter portion is preferably formed in a honeycomb structure. The through hole is preferably formed to have a cross-sectional area corresponding to the cross-sectional area of the nozzle portion.

According to another aspect of the present invention, (a) forming a pressure chamber in the first substrate, the ink chamber receiving ink and pressurizing the ink by volume reduction, and (b) in the second substrate, Forming a filter part including a plurality of through holes connected to a part and forming a flow path of ink, (c) forming a nozzle part connected to the filter part and allowing ink droplets to be discharged to the third substrate; d) there is provided an inkjet head manufacturing method comprising the step of sequentially stacking and bonding a first substrate, a second substrate, and a third substrate.

Step (a) is performed by (a1) applying a first photoresist to a first silicon layer of a silicon substrate where the first silicon layer and the second silicon layer are bonded through an oxide film, and (a2) a pressure chamber is to be formed. Selectively removing the first photoresist corresponding to the position, (a3) etching the first silicon layer to form a pressure chamber, and (a4) removing the photoresist remaining on the surface of the first silicon layer. It may include a step.

An ink inlet penetrating through the silicon substrate is further formed, and step (a1) further includes applying a second photoresist to the second silicon layer, and step (a2) corresponds to the position where the ink inlet is to be formed. Selectively removing the first photoresist and the second photoresist, wherein step (a3) includes etching the first silicon layer and the second silicon layer corresponding to the position where the ink inlet is to be formed. Further, step (a4) may further include removing the oxide film remaining at the position where the ink inlet is to be formed.

Step (b) comprises: (b1) applying the first photoresist to one surface of the silicon substrate, (b2) selectively removing the first photoresist corresponding to the position where the plurality of through holes are to be formed, (b3 ) Dry etching the silicon substrate to form a plurality of through holes, and (b4) removing the first photoresist remaining on the surface of the silicon substrate.

The cross-section of the through hole is hexagonal, and the filter portion is preferably formed in a honeycomb structure. The through hole is preferably formed to have a cross-sectional area corresponding to the cross-sectional area of the nozzle portion.

A reservoir is formed which penetrates the silicon substrate and stores ink supplied to the pressure chamber, and step (b2) further comprises selectively removing the first photoresist corresponding to the position where the reservoir is to be formed. Wherein step (b3) may further comprise dry etching the silicon substrate to form a reservoir. Step (b) may further include forming an oxide film on the surface of the silicon substrate after step (b4).

The silicon substrate is further formed with a restrictor, which is a flow path through which ink is supplied to the pressure chamber, in step (b), (b5) applying a second photoresist to the other surface of the silicon substrate, and (b6) the restrictor is formed. Selectively removing the second photoresist corresponding to the position, (b7) etching the silicon substrate corresponding to the position where the restrictor is to be formed, and (b8) removing the second photoresist remaining on the other side of the silicon substrate. It may further comprise the step of removing.

The nozzle part comprises a nozzle from which ink droplets are discharged, and a cone part of which one end is connected to the nozzle and the other end is connected to the filter part, and step (c) comprises: (c1) applying a first photoresist to one surface of the silicon substrate; (C2) selectively removing the first photoresist corresponding to the position where the nozzle is to be formed, (c3) dry etching the silicon substrate to form the nozzle, and (c4) a surface of the silicon substrate. And removing the remaining first photoresist.

Prior to step (c1), further comprising forming an oxide film on the surface of the silicon substrate, and step (c2) further includes selectively removing the oxide film of the portion from which the first photoresist has been removed, After c3), the method may further include forming an oxide film on the surface of the silicon substrate in the portion where the nozzle is formed.

Step (c), after step (c4), (c5) applying an etching resist to one surface of the silicon substrate, and applying a second photoresist to the other surface of the silicon substrate, (c6) corresponding to the position where the cone portion is to be formed Selectively removing the second photoresist, (c7) wet etching the silicon substrate to form a cone portion, and (c8) removing the second photoresist remaining on the surface of the silicon substrate. Can be.

Step (c6) may further include selectively removing the oxide film of the portion from which the second photoresist has been removed, and after step (c8), may further include forming an oxide film on the surface of the silicon substrate.

The first substrate, the second substrate and the third substrate are formed by processing a silicon substrate, and step (d) is preferably performed by silicon direct bonding. After step (d), the method may further include coupling the piezoelectric body to the first substrate corresponding to the position where the pressure chamber is formed.

Other aspects, features, and advantages other than those described above will become apparent from the following drawings, claims, and detailed description of the invention.

Hereinafter, preferred embodiments of an inkjet head and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings. Duplicate description thereof will be omitted.

1A is a longitudinal cross-sectional view illustrating a structure of an inkjet head according to an exemplary embodiment of the present invention, and FIG. 1B is a cross-sectional view illustrating a filter unit of the inkjet head according to an exemplary embodiment of the present invention. 1A and 1B, the pressure chamber 10, the through hole 11, the filter part 12, the cone part 14, the nozzle 16, the restrictor 18, the reservoir 20, the ink inlet port (22), the piezoelectric body 24 is shown.

In the inkjet head according to the present embodiment, the ink pressurized from the pressure chamber 10 is discharged through the nozzle portion including the cone portion 14 and the nozzle 16, and foreign substances contained in the ink or aggregated impurities are filtered out. The filter part 12 is interposed between the pressure chamber 10 and the nozzle part in order to prevent the blockage of 16.

That is, the filter portion 12 is connected to a part of the pressure chamber 10 that pressurizes the ink by volume reduction, and the ink passing through the filter portion 12 sequentially passes through the cone portion 14 and the nozzle 16. Is discharged in the form of droplets. The filter unit 12 is composed of a plurality of through holes 11 to provide a flow path for ink flowing from the pressure chamber 10 to the nozzle 16.

When the cross-sectional area of the through hole 11 is formed to be the same as that of the nozzle 16, foreign substances and the like contained in the ink are caught in the through hole 11 before being caught by the nozzle 16, thereby serving to filter ink. Since the filter part 12 is composed of a plurality of through holes 11, even if one through hole 11 is blocked by foreign matter or the like, ink is transferred from the pressure chamber 10 to the nozzle 16 through the other through holes 11. Can flow smoothly.

In addition, the cross-sectional area of the through hole 11 can be formed smaller or larger than the nozzle 16 within the range in which the ink can be effectively filtered according to the composition, viscosity of the ink, driving environment of the inkjet head, and the like.

The through hole 11 may be formed by an etching process having a straightness, as described below. Therefore, the shape of the cross-section of the through hole 11 may be variously formed, such as a circle, an ellipse, and a polygon. For example, as shown in FIG. 1B, when the cross-sectional shape of the through hole 11 is hexagonal, the overall shape of the filter part 12 is formed in a honeycomb structure to sufficiently fill the area of the through hole 11. The filter unit 12 can be manufactured with a secured structure while being secured.

FIG. 1A illustrates a piezoelectric inkjet head as an example, and forms a membrane driven on one surface of the pressure chamber 10 to increase or decrease the volume of the pressure chamber 10, and the piezoelectric 24 is coupled to the membrane. The ink contained in the pressure chamber 10 can be pressurized. In the case of the electrostatic inkjet head, a diaphragm may be formed on one surface of the pressure chamber 10, and an electrode may be disposed opposite the diaphragm to pressurize and discharge the ink contained in the pressure chamber 10.

As shown in FIG. 1A, the filter unit 12 and the nozzle unit are connected to one side of the pressure chamber 10, and the restrictor 18 forming a flow path for supplying ink to the pressure chamber 10 on the other side. Is connected. The restrictor 18 provides a flow resistance corresponding to the nozzle portion to prevent the ink pressurized by the pressure chamber 10 from flowing toward the ink inlet 22 without being discharged toward the nozzle 16. Do it.

As in the present embodiment, the nozzle 16 is provided by providing a sufficient flow path through the filter part 12 composed of the plurality of through holes 11 between the pressure chamber 10 and the nozzle 16 and filtering ink. It is possible to filter out impurities such as dust through a filter formed in the head itself without affecting the resistance ratio of the and the restrictor 18. Hereinafter, the manufacturing method of the inkjet head which concerns on a present Example is demonstrated.

2 is a flowchart illustrating a method of manufacturing an inkjet head according to an exemplary embodiment of the present invention, and FIGS. 3A, 3B, and 3C are upper and middle substrates and lower substrates of an inkjet head according to an exemplary embodiment of the present invention. 4A, 4B, and 4C are flow charts illustrating manufacturing processes of an upper substrate, an intermediate substrate, and a lower substrate of an inkjet head according to an exemplary embodiment of the present invention, respectively. Is a flowchart illustrating a manufacturing process of an inkjet head according to an exemplary embodiment of the present invention. 4A to 5, the silicon substrate 1, the upper substrate 2, the oxide film 3, the intermediate substrate 4, the photoresist 5, the lower substrate 6, the etching resist 7, The pressure chamber 10, the through hole 11, the filter part 12, the cone part 14, the nozzle 16, the restrictor 18, the reservoir 20, the ink inlet 22, and the piezoelectric body 24 are Is shown.

The inkjet head manufacturing process according to the present embodiment is an application of a semiconductor process, and after fabricating a substrate constituting each layer of the inkjet head by etching a silicon wafer, it is characterized in that the inkjet head structure is manufactured by laminating them. In this embodiment, a total of three substrates, namely, an upper substrate 2, an intermediate substrate 4, and a lower substrate 6 are stacked to form an inkjet head structure, and a piezoelectric inkjet is formed by bonding a piezoelectric material 24 on a membrane. The case of manufacturing a head is demonstrated.

First, the pressure chamber 10 is formed on the upper substrate 2 as shown in FIG. 4A (100). As described above, the pressure chamber 10 is a head structure that receives ink and pressurizes the ink by a decrease in volume.

Next, as shown in FIG. 4B, the filter part 12 is formed on the intermediate substrate 4 (120). As described above, the filter unit 12 is connected to the pressure chamber 10 to provide a flow path for the ink flowing toward the nozzle 16, and a plurality of through holes for filtering foreign substances contained in the ink. It is a head structure containing (11).

Next, as shown in FIG. 4C, a nozzle part is formed on the lower substrate 6 (140). The nozzle portion is a portion through which the filtered ink is injected through the filter portion 12 to the outside, and a funnel-shaped cone portion 14 connected to the filter portion 12 and a nozzle connected to the cone portion 14 and exposed to the outside. It consists of (16).

Finally, after the lower substrate 6, the intermediate substrate 4, and the upper substrate 2 are sequentially stacked and bonded (170), a position corresponding to the pressure chamber 10 of the upper substrate 2, that is, at the membrane The piezoelectric body 24 is coupled to the corresponding portion 172 to complete the manufacturing of the piezoelectric inkjet head according to the present embodiment.

As described later, when the upper substrate 2, the intermediate substrate 4, and the lower substrate 6 are manufactured by etching the silicon substrate 1 by applying a semiconductor manufacturing process, a high temperature is not used without a separate bonding agent. Each substrate may be bonded to each other by silicon direct bonding, which is a method of pressing and bonding at (170). Accordingly, a durable head structure can be obtained without reacting to the physical and chemical properties of the ink contained in the head.

Hereinafter, an embodiment of a more detailed manufacturing process of the upper substrate 2, the intermediate substrate 4, and the lower substrate 6 will be described.

In order to manufacture the upper substrate 2 on which the pressure chamber 10 is formed, it is preferable to use the silicon substrate 1 in which two layers of silicon layers are bonded with the oxide film 3 interposed therebetween. In this case, one silicon layer is a part of which a portion is etched to form the pressure chamber 10, and the other silicon layer forms a surface of the pressure chamber 10 to serve as a membrane, so that the pressure chamber ( 10) the silicon layer to be formed corresponds to the thickness of the pressure chamber 10, the thickness of the silicon layer to serve as the membrane corresponds to the thickness of the membrane to fabricate the silicon substrate (1).

The upper substrate 2 may be formed with a pressure chamber 10 and an ink inlet 22, the pressure chamber 10 is formed by digging a portion of the silicon substrate 1, the ink inlet 22 is a silicon substrate It forms by drilling the through-hole 11 in another part of (1). To this end, as shown in FIG. 4A (a), the photoresist 5 is applied to the surfaces of the two silicon layers constituting the silicon substrate 1 (102). The photoresist 5 is a material including a photosensitive material that can selectively remove only a desired portion through exposure and development.

Next, as shown in (b) of FIG. 4A, a position where the pressure chamber 10 is to be formed by exposing and developing the photoresist 5 coated on the silicon layer having a thickness corresponding to the height of the pressure chamber 10 ( 9) selectively remove only. In addition, the photoresist 5 applied to both surfaces of the silicon substrate 1 is exposed and developed to selectively remove only the position 21 at which the ink inlet 22 is to be formed (104).

Next, as shown in (c) of FIG. 4A, the pressure chamber 10 is formed by etching the silicon layer at the position 9 at which the pressure chamber 10 is to be formed. When forming the pressure chamber by etching in a direction perpendicular to the surface of the silicon substrate, it is recommended to apply a dry etching process having a straightness such as 'ICP Inductively Coupled Plasma Reactive Ion Etching'.

The silicon substrate 1 for manufacturing the upper substrate 2 has a structure in which a silicon layer having a thickness corresponding to the height of the pressure chamber 10 and a silicon layer corresponding to the thickness of the membrane are bonded with an oxide film 3 interposed therebetween. Since the thickness of the silicon layer bonded to the oxide film 3 is adjusted, the size of the pressure chamber 10 and the thickness of the membrane can be adjusted.

The silicon layer at the position 21 at which the ink inlet 22 is to be formed is etched to form an ink inlet 22 that is blocked by the oxide film 3 (106). Finally, as shown in FIG. 4A (d), the photoresist 5 remaining on the surface of the silicon substrate 1 is peeled off, and the oxide film 3 clogged in the ink inlet 22 is removed (108). ). In this process, one surface of the pressure chamber 10, that is, the oxide film 3 in contact with the membrane may be removed together.

The filter part 12 formed in the intermediate substrate 4 is composed of a plurality of through holes 11 passing through the intermediate substrate 4. That is, as shown in (e) of FIG. 4B, the photoresist 5 is applied to one surface of the silicon substrate 1 (121), and is exposed and developed to only the position 8 at which the plurality of through holes 11 are to be formed. Optionally remove Meanwhile, the intermediate substrate 4 may further include a reservoir 20 for storing ink supplied to the pressure chamber 10, as shown in FIG. 4B. The reservoir 20 may also be formed in the middle of the intermediate substrate 4. It is formed by drilling through the substrate 4. Therefore, in parallel to the process of forming the through hole 11, the photoresist 5 is applied and only the position 19 where the reservoir 20 is to be formed is selectively removed (123).

As described above, in order to form the honeycomb structure of the filter portion 12 with the cross-sectional shape of the through hole 11 as a hexagon, it is preferable to selectively remove the photoresist 5 after exposure and development in the form of a honeycomb. . In addition, the photoresist 5 can be exposed and developed such that the cross-sectional area of the through hole 11 is equal to or larger than or smaller than the cross-sectional area of the nozzle portion.

Next, as shown in FIG. 4B (f), the silicon substrate 1 is etched to form the plurality of through holes 11 and the reservoir 20 (125). Since the through-hole 11 plays a role of filtering ink, the through-hole 11 is formed in the shape of a fine pipe. Therefore, the through-hole 11 may be etched by a dry etching method having a straightness such as 'ICP RIE'. As described above, the reservoir 20 may also be formed in parallel with the through-hole 11 forming process.

Since the plurality of through holes 11 constituting the filter part 12 are formed through the intermediate substrate 4, the shape and length of the through holes 11 are applied to the intermediate substrate 4. It can be determined by adjusting the shape and the thickness of the intermediate substrate (4) to selectively remove.

Next, as shown in FIG. 4B (g), the photoresist 5 remaining on the surface of the silicon substrate 1 is removed (127), and as shown in FIG. 4B (h), the surface of the silicon substrate 1 is removed. An oxide film 3 is formed (wet oxidation) 129 to complete the manufacture of the intermediate substrate 4.

On the other hand, the intermediate substrate 4 may be connected to the reservoir 20 to form a restrictor 18, the restrictor 18 is a flow path for supplying the ink stored in the reservoir 20 to the pressure chamber 10. In addition, the silicon substrate 1 may be partially etched because it is a portion that provides a flow resistance corresponding to the nozzle 16 with respect to the ink pressurized from the pressure chamber 10.

As described above, a process of forming the restrictor 18 on the intermediate substrate 4 may be added prior to, in parallel with, or subsequent to the step of manufacturing the intermediate substrate 4. In order to form the retarder 18, as shown in Fig. 4B (a), the photoresist 5 is applied to the surface on which the part of the silicon substrate 1 is removed (122), and Fig. 4B (b). Selectively removes only the location 17 at which the restrictor 18 is to be formed (124).

Next, as shown in FIG. 4B (c), the silicon substrate 1 of the portion where the photoresist 5 has been removed is etched to form the restrictor 18 (126), and as shown in FIG. 4B (d). The photoresist 5 remaining on the surface of the silicon substrate 1 is removed (128). Like the pressure chamber 10 described above, the restrictor 18 may also be subjected to a dry etching process in order to form it in a direction perpendicular to the surface of the silicon substrate 1.

Since the plurality of through holes 11 and the reservoir 20 are formed through the intermediate substrate 4, the through holes 11 are opened to both sides of the silicon substrate 1 after the structure is formed. Will be. Therefore, it is preferable to form the restrictor 18 before the through hole 11 and the reservoir 20 are formed, and the through hole 11 is formed on the surface opposite to the surface on which the restrictor 18 is formed in the intermediate substrate 4. ) And the reservoir 20 forming process.

In order to form the through-hole 11 and the reservoir 20 after the formation of the restrictor 18, the process of removing the photoresist 5 on the surface on which the restrictor 18 is formed as shown in FIG. It is preferable to apply the photoresist 5 to the opposite side.

A nozzle portion is formed in the lower substrate 6, and the nozzle portion forms a flow path of ink between the nozzle 16 through which ink droplets are discharged, and the filter portion 12 of the nozzle 16 and the intermediate substrate 4 ( 14). Since the width of the filter portion 12 is larger than the width of the nozzle 16, the cone portion 14 may be formed in a funnel shape to guide ink passing through the filter portion 12 to the nozzle 16.

In order to manufacture the lower substrate 6, the nozzle 16 is drilled on one surface of the silicon substrate 1, and the cone portion 14 is formed on the other surface so that the nozzle 16 and the cone portion 14 communicate with each other. Since the nozzle 16 corresponds to a structure in which precision and accuracy are important in its shape such as the shape and diameter of the cross section, it is preferable to form the nozzle by dry etching having a straightness, and the cone part 14 must be formed to have an inclined surface in the shape of a funnel, so that it is wet. It is preferable to apply an etching process, so that the nozzles 16 and the cone portions 14 are formed on both sides of the silicon substrate 1 so as to communicate with each other.

First, as shown in FIG. 4C (a), an oxide film (SiO ₂ ) 3 is formed on the surface of the silicon substrate 1 (142), and as shown in FIG. 4C (b), one surface of the silicon substrate 1 After applying the photoresist 5 to the substrate 144, the photoresist 5 is removed by exposure and development to remove the photoresist 5 at the position 15 at which the nozzle 16 is to be formed, and the oxide film 3 as shown in FIG. ) Is optionally removed (146).

Next, as shown in FIG. 4C (d), the silicon substrate 1 is etched by dry etching having straightness to form nozzles 16 of a required depth (148). The photoresist 5 remaining on the surface of the silicon substrate 1 is removed (150), and an oxide film 3 is formed on the inner circumferential surface of the nozzle 16 on which the oxide film 3 is not deposited due to dry etching ( 152). The oxide film 3 serves to protect the nozzle 16 from damaging the nozzle 16 by the penetration of the etchant into the inner circumferential surface of the nozzle 16 in the wet etching process for forming the cone portion 14 described later.

Next, since the cone portion 14 is formed on the side opposite to the side on which the nozzle 16 is formed, the photoresist 5 is applied to the surface opposite to the side on which the nozzle 16 is formed, as shown in Fig. 4C. 154, exposure and development to selectively remove the position 13 at which the cone portion 14 is to be formed, as shown in FIG. 4C, and then selectively remove the oxide film of the portion as shown in FIG. 4C. (156). In this process, an etching resist 7 is applied to the surface of the side on which the nozzle 16 of the silicon substrate 1 is formed so as to prevent unnecessary etching on the opposite side in the wet etching process for forming the cone portion 14.

Next, as shown in FIG. 4C (h), the silicon substrate 1 is wet etched to form the cone portion 14 (158). Since wet etching is a process of etching the silicon substrate 1 by a chemical reaction between an etchant and silicon, the silicon substrate 1 has a predetermined inclination angle as shown in FIG. 4C by the molecular arrangement angle of silicon. Is etched. Thus, the cone part 14 is formed by wet etching, and it communicates with the nozzle 16 formed in the opposite surface of the silicon substrate 1. As shown in FIG. As a result, the nozzle portion penetrating the lower substrate 6 is formed by the cone portion 14 and the nozzle 16 connected thereto.

Next, as shown in FIG. 4C (i), the photoresist 5 and the oxide film 3 remaining on the surface of the silicon substrate 1 are removed (160), and as shown in FIG. 4C (j), the silicon substrate is removed. The oxide film 3 is grown on the surface of (1) (162) to complete the fabrication of the lower substrate 6.

Here, the process of communicating the nozzle 16 and the cone portion 14 by forming the cone portion 14 after forming the nozzle 16 has been described as an example. In contrast, the cone portion 14 is first formed and the nozzle 16 is formed. Of course, it is also possible to form a communication between the nozzle 16 and the cone portion 14.

After fabricating the upper substrate 2, the intermediate substrate 4, and the lower substrate 6 as described above, the substrates are sequentially stacked as shown in FIG. 5 (a), and the silicon as shown in FIG. 5 (b). After bonding by direct bonding, the piezoelectric body 24 is bonded onto the surface of the upper substrate 2 corresponding to the position of the pressure chamber 10, that is, the membrane, as shown in FIG. This allows a piezoelectric inkjet head to be produced.

Many embodiments other than the above-described embodiments are within the scope of the claims of the present invention.

According to a preferred embodiment of the present invention as described above, by providing a plurality of through-holes having a cross-sectional area corresponding to the cross-sectional area of the nozzle in the nozzle portion of the inkjet head by itself to filter dust or foreign matter aggregated in the ink, The nozzle of the inkjet head can be prevented from clogging, the life of the industrial inkjet head can be extended, and stable discharge performance can be ensured.

Claims (21)

A pressure chamber which contains ink and pressurizes the ink by volume reduction; A filter part connected to a part of the pressure chamber and including a plurality of through holes forming a flow path of the ink; A nozzle part connected to the filter part and configured to discharge ink droplets, The membrane is formed on one surface of the pressure chamber, the inkjet head, characterized in that the volume of the pressure chamber is increased or decreased by the driving of the membrane. delete The method of claim 1, An inkjet head, characterized in that the piezoelectric body is coupled to the membrane. The method of claim 1, And a restrictor connected to another portion of the pressure chamber, the restrictor forming a flow path for supplying the ink to the pressure chamber. The method of claim 1, The cross-section of the through hole is hexagonal, the ink jet head, characterized in that formed in a honeycomb (honeycomb) structure. The method of claim 1, The through-holes are formed to have a cross-sectional area corresponding to the cross-sectional area of the nozzle portion. (a) forming a pressure chamber in the first substrate, the pressure chamber containing ink and pressurizing the ink by volume reduction; (b) forming a filter part on the second substrate, the filter part including a plurality of through holes connected to a part of the pressure chamber and forming a flow path of the ink; (c) forming a nozzle unit on the third substrate, the nozzle unit being connected to the filter unit and discharging ink droplets; And and (d) sequentially stacking and bonding the first substrate, the second substrate, and the third substrate. The method of claim 7, wherein Step (a) is, (a1) applying a first photoresist to the first silicon layer of the silicon substrate where the first silicon layer and the second silicon layer are bonded through an oxide film; (a2) selectively removing the first photoresist corresponding to the position where the pressure chamber is to be formed; (a3) etching the first silicon layer to form the pressure chamber; And (a4) removing the photoresist remaining on the surface of the first silicon layer. The method of claim 8, An ink inlet penetrating the silicon substrate is further formed, The step (a1) further comprises applying a second photoresist to the second silicon layer, Step (a2) further includes the step of selectively removing the first photoresist and the second photoresist corresponding to the position where the ink inlet is to be formed, The step (a3) further includes etching the first silicon layer and the second silicon layer corresponding to the position where the ink inlet is to be formed, The step (a4) further comprises the step of removing the oxide film remaining at the position where the ink inlet is to be formed. The method of claim 7, wherein Step (b) is, (b1) applying a first photoresist to one surface of the silicon substrate; (b2) selectively removing the first photoresist corresponding to a position where the plurality of through holes are to be formed; (b3) dry etching the silicon substrate to form the plurality of through holes; And (b4) removing the first photoresist remaining on the surface of the silicon substrate. The method of claim 10, The cross-section of the through-hole is hexagonal, the filter unit is characterized in that the honeycomb (honeycomb) structure formed inkjet head manufacturing method. The method of claim 10, And the through-holes are formed to have a cross-sectional area corresponding to the cross-sectional area of the nozzle unit. The method of claim 10, A reservoir penetrating the silicon substrate and storing ink supplied to the pressure chamber is further formed. Step (b2) further includes the step of selectively removing the first photoresist corresponding to the position where the reservoir is to be formed, The step (b3) further comprises the step of dry etching the silicon substrate to form the reservoir. The method according to claim 10 or 11, wherein The step (b) after the step (b4), further comprising the step of forming an oxide film on the surface of the silicon substrate. The method of claim 10, The silicon substrate further includes a restrictor that is a flow path through which the ink is supplied to the pressure chamber, Step (b) is, (b5) applying a second photoresist to the other surface of the silicon substrate; (b6) selectively removing the second photoresist corresponding to the location where the restrictor is to be formed; (b7) etching the silicon substrate corresponding to the position where the restrictor is to be formed; And (b8) removing the second photoresist remaining on the other surface of the silicon substrate. The method of claim 7, wherein The nozzle part is composed of a nozzle for discharging ink droplets, and a cone part of which one end is connected to the nozzle and the other end is connected to the filter part. Step (c) is, (c1) applying a first photoresist to one surface of the silicon substrate; (c2) selectively removing the first photoresist corresponding to the position where the nozzle is to be formed; (c3) dry etching the silicon substrate to form the nozzle; And (c4) removing the first photoresist remaining on the surface of the silicon substrate. The method of claim 16, Before the step (c1), further comprising the step of forming an oxide film on the surface of the silicon substrate, Step (c2) further includes the step of selectively removing the oxide film of the portion from which the first photoresist has been removed, After the step (c3), further comprising the step of forming an oxide film on the surface of the silicon substrate of the portion where the nozzle is formed. The method of claim 17, Step (c) is after the step (c4), (c5) applying an etching resist to one surface of the silicon substrate and applying a second photo resist to the other surface of the silicon substrate; (c6) selectively removing the second photoresist corresponding to the position where the cone portion is to be formed; (c7) wet etching the silicon substrate to form the cone portion; And and (c8) removing the second photoresist remaining on the surface of the silicon substrate. The method of claim 18, Step (c6) further includes the step of selectively removing the oxide film of the portion from which the second photoresist has been removed, After the step (c8), further comprising the step of forming an oxide film on the surface of the silicon substrate. The method of claim 7, wherein And said first substrate, said second substrate and said third substrate are formed by processing a silicon substrate, and said step (d) is performed by silicon direct bonding. The method of claim 7, wherein After step (d) above, Coupling a piezoelectric body to the first substrate corresponding to the position where the pressure chamber is formed.

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