KR100641286B1 - Micro high density ink jet print head and method of fabricating the same using piezoelectric film type - Google Patents

Abstract

A micro high precision ink jet print head and a method for manufacturing the same using a piezoelectric film type are provided to realize a head structure by using only two silicon substrates without using a sacrificial layer. In a micro high precision ink jet print head using a piezoelectric film type, a reservoir(23) storing ink and a pressure chamber in which a fluid introduced from the reservoir stays before discharge are penetratingly formed at one side and the other side of an upper substrate(200). A lower substrate(300) includes a fluid spraying part(60) composed of a fluid discharging port(61), a fluid spraying port(63), and a spraying diffuser(62), a fluid path(31) connected to the reservoir, and a path diffuser(33) having a cross section gradually increasing from the fluid path to the pressure chamber. And a piezoelectric actuator(50) provides exhausted pressure to the fluid of the pressure chamber.

Description

Micro High Density Ink Jet Print Head and Method of Fabricating The Same Using Piezoelectric Film Type}

1 is a side sectional view of a head according to the prior art;

Figure 2 is a side cross-sectional view of a droplet ejection head in accordance with a preferred embodiment of the present invention.

3 is an enlarged side cross-sectional view of a piezoelectric actuator.

4 is a plan view showing an upper surface of the upper substrate.

5 is a plan view showing an upper surface of the lower substrate.

Figure 6 is a plan view showing the arrangement of the piezoelectric actuator disposed on the upper surface of the upper substrate.

7A to 7K are plan views illustrating manufacturing steps of an upper substrate.

8A to 8E are plan views illustrating manufacturing steps of the lower substrate.

9 is a cross-sectional view of the head completed by bonding the upper substrate and the lower substrate.

* Brief description of the major symbols in the drawings *

200: upper substrate 300: lower substrate

20: upper base substrate 30: lower base substrate

40: elastic membrane 50: piezoelectric actuator

60: fluid injection unit

The present invention relates to a piezoelectric droplet ejection head and a method of manufacturing the same, and more particularly, to a droplet ejection head having a flow path structure and a simplified lamination structure capable of inducing a smooth flow of the injection target fluid and a method of manufacturing the same. will be.

Piezoelectric droplet ejection head is a device mainly used to eject micro ink droplets for printing at a desired position on a recording paper in an office inkjet printer. A part of a pressure chamber filled with ink is composed of an elastic film and mechanically applied by an applied voltage. As the elastic membrane is deformed by attaching a piezoelectric element that causes deformation to one surface of the elastic membrane, and the elastic membrane is deformed by bending deformation of the piezoelectric element, the volume of the ink chamber chamber is reduced and the pressure is increased so that the ink communicates with the ink chamber chamber. It is a device to discharge to the outside in the form of droplets (microfluidic droplets, droplets) through the nozzle.

In addition, such droplet spraying devices can be directly applied without conventional repetitive film formation and corrosion technology to implement electronic circuits or circuits required for electronic products in displays such as organic EL and LCD, as well as in conventional inkjet printers. Has recently attracted attention as an alternative technical means by which the material can be formed in a desired position.

Meanwhile, the droplet ejection head has a thermal method in which a bubble formed by heat generated by a heater pushes ink in an ink chamber out of a nozzle in addition to the above-described piezoelectric method, but it is difficult to apply to a heat sensitive material. The application industry is more limited than piezoelectric.

As such, the piezoelectric droplet ejection head has a nozzle, an ink chamber, a piezoelectric element, a flow path, and a reservoir (reservoir) as a main component, and three or more plates are stacked to form these parts. It is common to select but prior art that simplifies its structure using two substrates has been disclosed in US Patent US6378996, a representative drawing of which is shown in FIG.

Referring to FIG. 1, a conventional droplet ejection head includes a flow path forming substrate 1 and a nozzle forming substrate 2, and an elastic film 3 is formed between the flow path forming substrate and the nozzle forming substrate. In addition, an ink reservoir 4, a communicating portion 5, a narrow portion 6, and a pressure chamber 7 are formed in the flow path forming substrate along the flow path through which ink flows. The nozzle forming substrate has a nozzle 8 and a piezoelectric element. The piezoelectric layer is formed on the upper surface of the elastic film 10 at the position corresponding to the piezoelectric element holding part, and the free electrode part 9 is formed in the order of the lower electrode 11, the piezoelectric element 12, and the upper electrode 13. Formed.

When describing the general manufacturing method of the conventional droplet ejection head having the configuration and structure as described above, first, the communicating part, the narrow part and the pressure chamber are formed by etching using a mask on one side of the silicon single crystal to be used as the flow path forming substrate. After filling, the sacrificial layer is filled. Thereafter, an elastic film and a piezoelectric layer are formed on an upper surface of the flow path forming substrate filled with the sacrificial layer, and then an ink reservoir is formed on the lower surface of the flow path forming substrate by wet etching, and then the sacrificial layer is formed by wet etching or dry etching. By removing, the communication part, the narrow part, and the pressure chamber are formed again.

However, as can be seen in the above-described manufacturing process, the manufacturing method of the prior art involves the formation of a sacrificial layer and the removal process by wet etching, and thus, the manufacturing process is complicated. Therefore, it is desirable to develop a manufacturing method that can directly form a space required. do.

In addition, as described above, in order to apply the inkjet technology to various application fields, it should be applicable to a material having viscosity and other various physical properties. It is necessary to develop a flow path structure that can induce a smooth flow and improve the spraying performance of the droplets.

According to the problems of the prior art and the need for technology development, the present invention has a purpose to provide a simple droplet ejection head structure and its manufacturing method.

In addition, another object of the present invention is to propose a flow path structure and an injection structure capable of inducing a more smooth flow and injection in order to improve the injection performance of the injection target material in the internal structure of the droplet injection head.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings. Prior to this, the terms or words used in the present specification and claims are defined in the technical spirit of the present invention on the basis of the principle that the inventor can appropriately define the concept of the term in order to explain his invention in the best way. It must be interpreted to mean meanings and concepts.

In order to achieve the above object, the present invention is connected to the reservoir 23 and the reservoir 23 in which ink is introduced and stored at one side, and the pressure chamber 22 staying before the fluid introduced from the reservoir 23 is discharged. The upper substrate 200 formed therethrough with one side and the other side, respectively; The fluid discharge port 61 and the fluid discharge port 61 connected to the pressure chamber 22 and the fluid are injected, and have a diameter larger than that of the fluid discharge port 61 and the fluid discharge port 61 and the fluid injection port 63. It is connected to the fluid ejection port 60 consisting of the injection diffuser 62 is gradually increased in cross-sectional area from the fluid discharge port 61 toward the fluid injection port 63, and the reservoir 23 of the upper substrate 200 A fluid passage 31 connected to the fluid passage 31 and a fluid passage 31 connected to the fluid passage 31 and the pressure chamber 22 and having an increased cross-sectional area from the fluid passage 31 toward the pressure chamber 22. A lower substrate 300 formed of; And a piezoelectric actuator integrally formed on an upper surface of the pressure chamber 22 of the upper substrate 200 to change the volume of the pressure chamber 22 by bending deformation to provide a discharge pressure to the fluid in the pressure chamber 22 ( 50) is provided, including the lower substrate 300 and the piezoelectric actuator 50 is provided with an ultra-small precision droplet injection head using a piezoelectric method, characterized in that the upper substrate 200 is formed by bonding to each other. .

In addition, the upper portion of the pressure chamber 22 of the upper substrate 200 is a silicon oxide film 41 and the silicon nitride film 42 are sequentially deposited elastic film (bending deformation by driving the piezoelectric actuator 50 ( It provides an ultra-small precision droplet ejection head using a piezoelectric method characterized in that it serves as 40).

In addition, it provides a microscopic precision droplet injection head using a piezoelectric method characterized in that it further comprises a buffer film 43 formed by forming a silicon oxide film on the upper surface of the elastic film 40 again.

In addition, the preparing step of the upper base substrate 20 and the lower base substrate made of single crystal silicon; An elastic film forming step of forming an elastic film 40 that is easily bent and deformed on an upper surface of the upper base substrate 20; and a piezoelectric for providing a pressure for discharging fluid on the upper surface of the upper base substrate 20; A piezoelectric actuator forming step of forming an actuator 50; and a pressure chamber 22 formed on one side of the upper base substrate 20 corresponding to the position of the piezoelectric actuator 50, and the fluid flows into and stored on the other side. A pressure chamber for forming the reservoir 23 and a reservoir forming step; a manufacturing step of the upper substrate 200; and a fluid spraying part 60 formed through the lower base substrate and a flow path diffuser 33 on the upper surface of the lower base substrate. ) And a lower substrate 300 for forming the fluid passage 31 by an etching process; And a bonding step of forming a droplet injection head by bonding the upper substrate 200 and the lower substrate 300 to each other, thereby providing a method of manufacturing a microscopic precision droplet injection head using a piezoelectric method.

In addition, the pressure chamber and the reservoir forming step provides a method of manufacturing a microscopic precision droplet injection head using a piezoelectric method, characterized in that for forming the pressure chamber and the reservoir using the Deep-RIE etching technology and RIE etching technology.

In addition, the microfluidic droplet injection head using the piezoelectric method, characterized in that the flow path diffuser 33 and the fluid flow path 31 on the upper surface of the fluid injection unit 60 and the lower base substrate are formed simultaneously by an etching process. It provides a manufacturing method.

In addition, the injection diffuser 62 of the fluid injection unit 60 is an ultra-small precision using a piezoelectric method, characterized in that formed by anisotropic wet etching in order to implement a diffuser shape in which the cross-sectional area is gradually increased with respect to the injection direction of the fluid. Provided is a method for producing a droplet ejection head.

In addition, the fluid discharge port 61 of the fluid injection unit 60 is a method of manufacturing a microscopic precision droplet injection head using a piezoelectric method, characterized in that formed through the lower substrate 300 by Deep-RIE etching technology. to provide.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the illustrated drawings.

The present invention is made by stacking the upper substrate 200 and the lower substrate 300 to be bonded to each other, the upper substrate 200 and the lower substrate 300 is dry or wet etching or photomasking and micro-machining work more easily It is desirable to be made of a single crystal silicon substrate for application.

Each of the upper substrate 200 and the lower substrate 300 is provided with components forming the fluid passage 31, and a piezoelectric actuator 50 generating a driving force for discharging the fluid is provided on the upper substrate.

The fluid passage 31 may include a reservoir 23 into which fluid is introduced and stored from a container (not shown), a supply passage and a flow path diffuser 33 for supplying a fluid from the reservoir 23 to the pressure chamber 22. The fluid to be discharged is filled with a pressure chamber 22 in which the volume change is changed by the piezoelectric actuator 50 to discharge the fluid, and the fluid injection unit 60 through which the fluid is discharged.

2 is a side cross-sectional view of the droplet ejection head according to a preferred embodiment of the present invention, FIG. 3 is an enlarged side cross-sectional view of the piezoelectric actuator 50, and FIG. 4 is a plan view showing an upper surface of the upper substrate 200. .

Referring to FIG. 2 to FIG. 4 together, the upper substrate 200 will be described first, and both sides of the upper substrate 20 prepared as a starting substrate to form the upper substrate 200 as shown in FIGS. 2 and 3. An upper pressure chamber 22a and a reservoir 23 are formed therein, and an elastic film 40 having a silicon oxide film 41 and a silicon nitride film 42 stacked thereon is formed on an upper surface of the upper base substrate 20. The silicon oxide film 43 is additionally formed on the upper surface of the elastic film 40 as a buffer film to facilitate the formation of the piezoelectric actuator 50 to be described later.

The elastic membrane 40 is formed integrally therewith, and is deformed integrally with the piezoelectric actuator 50 according to the driving of the piezoelectric actuator 50 which is bent and deformed by an applied voltage, thereby causing the volume of the upper pressure chamber 22a to be reduced. It will act as a diaphragm to change.

In addition, the silicon oxide film 41 is a material that can serve as an etch stop layer in the etching process for forming the pressure chamber 22 and the reservoir 23 in the manufacturing process to be described later, The silicon nitride film 42 is a more advantageous material for forming a stable elastic film 40 if a film forming method (primarily an optimized chemical vapor deposition method) capable of realizing a low residual stress under stress control is used.

In addition, the silicon oxide film 43 adhered to the upper surface of the elastic film 40 may facilitate electrode deposition with the upper electrode 53 among the components of the piezoelectric actuator 50, and the upper base substrate 20 and the piezoelectric actuator ( 50) acts as a buffer to inhibit diffusion between and control thermal stress.

On the other hand, the buffer film generally refers to a thin film that can mitigate the deformation of the entire multilayer thin film structure by the mutual diffusion between the two materials or the residual stress difference between the two materials, as described above, the silicon oxide film The buffer film formed as a function serves to prevent buckling of the multilayer thin film structure that may occur in a step of forming the elastic film, the electrode, and the piezoelectric film described later.

The piezoelectric actuator 50 includes a lower electrode 51 serving as a common electrode formed on an upper surface of the elastic film formed on the upper base substrate 20, a piezoelectric film 52 that is bent and deformed according to the application of voltage, and a piezoelectric film. Upper electrodes 53 serving as driving electrodes for applying a voltage to 52 are sequentially stacked. The lower electrode 51 is formed to be wider than the area of the piezoelectric film 52, and an interlayer insulating film is inserted around the piezoelectric film 52 to insulate the upper electrode 53 and the lower electrode 51. After that, it is preferable to stack the upper electrode 53.

In addition, each piezoelectric actuator 50 is a material having a diaphragm structure that can be driven in a bending mode, and the material of the upper electrode 53 and the lower electrode 51 may be Pt, Au, Al, or the like. Materials may be used and the piezoelectric film 52 may be a conventional Lead Zircomate Titanate (PZT) ceramic material.

Meanwhile, in the case of the lower substrate 300, as shown in FIG. 3, the upper substrate is formed on one side of an upper surface of the lower substrate 30 prepared as the starting substrate to form the lower substrate 300, as in the upper substrate 200. The fluid flow path 31 connected to the reservoir 23 of the 200 is formed to have a predetermined depth, and the flow path diffuser 33 connecting one end of the fluid flow path 31 and the upper pressure chamber 22a includes the fluid. It is formed to a depth shallower than the depth of the flow path (31).

In addition, the lower pressure chamber 32a having the same area as the upper pressure chamber 22a of the upper substrate 200 at a position corresponding to the upper pressure chamber 22a of the upper substrate 200 on the other side of the upper surface of the lower base substrate 30. ) Is formed to form a pressure chamber 22 composed of an upper pressure chamber 22a and a lower pressure chamber 32a by joining the upper substrate 200 and the lower substrate 300. However, the pressure chamber 22 may be composed of only the upper pressure chamber 22 depending on the thickness of the lower substrate 300 and the depth or shape of the fluid injection unit 60 to be described later, but the manufacturing method to have such a configuration. Silver may increase the number of manufacturing steps of the upper substrate and may damage the silicon substrate itself, and thus, it is preferable to manufacture the silicon substrate to have the above-described configuration by dispersing the manufacturing steps on the upper and lower substrates.

The lower surface of the lower pressure chamber 22 is formed with a fluid injection unit (60). The fluid injection part 60 is formed below the lower pressure chamber 22 and has a constant diameter and vertically penetrates the fluid discharge port 61 and the fluid discharge port of the oxynitride film 34 formed on the bottom surface of the lower substrate 300. At the position corresponding to 61, the fluid ejection opening 63 having the same depth as the oxynitride film 34 and the diameter larger than the fluid ejection opening 61, and from the fluid ejection opening 61 toward the fluid ejection opening 63, It consists of a spray diffuser 62 whose cross-sectional area is gradually increased. The jet diffuser 62 has a diffuser shape in which the cross-sectional area is increased in the jetting direction so that the fluid jetted at high speed can be more smoothly jetted, as opposed to the flow path diffuser 33 described above.

FIG. 5 is a plan view showing an upper surface of the lower substrate, and FIG. 6 is a plan view of an upper substrate which shows the arrangement of the piezoelectric actuators disposed on the upper surface of the upper substrate.

The flow path diffuser 33 smoothly flows the fluid supplied from the fluid passage 31 connected to the reservoir 23 to the pressure chamber 22, as shown in FIG. 5, and the fluid by the piezoelectric actuator 50. It is preferable to have a diffuser shape in which the cross-sectional area is increased while going from the fluid passage 31 toward the pressure chamber 22 in order to suppress the back flow of the fluid from the pressure chamber 22 to the fluid passage 31 when it is discharged.

Therefore, when the piezoelectric actuator 50 is operated at a high frequency for high-speed fluid injection, the sudden pressure change in the pressure chamber 22 caused by this causes a rapid increase in the flow velocity of the fluid and the fluid flow path from the pressure chamber 22. Due to the structure of the flow path diffuser 33 having a smaller cross-sectional area toward 31), the movement of the fluid is restricted toward the fluid flow path 31 so that the pressure change is more concentrated on the fluid discharge port 61 to remind the motion of the fluid. It is directed to the fluid discharge port (61).

Referring to the operation of the piezoelectric droplet injection head according to the present invention having such a configuration as follows. The fluid supplied from the fluid container (not shown) into the reservoir 23 flows into the pressure chamber 22 through the fluid flow path 31 and the flow path diffuser 33.

Thereafter, when a voltage is applied to the piezoelectric film 52 through the upper electrode 53 of the piezoelectric actuator 50 in a state where the fluid is filled in the pressure chamber 22, the piezoelectric film 52 is bent and deformed accordingly. ) Is deflected downward.

Due to the deformation of the elastic membrane 40, the volume of the pressure chamber 22 is reduced. As a result, the pressure in the pressure chamber 22 causes the fluid in the pressure chamber to be discharged from the fluid outlet 61 and the jet diffuser 62. And it is injected to the outside through the fluid injection port (63).

Then, when the voltage applied to the piezoelectric film 52 of the piezoelectric actuator 50 is cut off, the piezoelectric film 52 is restored to its original form, and as the elastic film 40 is restored, the volume increases relatively. Pressure reduction in the pressure chamber 22 occurs. Due to the pressure decrease in the pressure chamber 22, the fluid in the fluid passage 31 flows into the pressure chamber 22 through the flow path diffuser 33.

5 is a plan view showing the arrangement of the piezoelectric actuator 50 disposed on the upper surface of the upper substrate 200, Figure 6 is a plan view showing the upper surface of the lower substrate.

As shown in FIG. 5, the upper electrode and the lower electrode are connected to each of the piezoelectric actuators, and each has an independent arrangement structure to which a separate voltage can be applied, and the reservoir, the fluid flow path, the flow path diffuser, and the pressure chamber are connected to each other. Formed to form the entire flow path of the fluid.

Hereinafter, a method of manufacturing a piezoelectric droplet injection head according to a preferred embodiment of the present invention will be described with reference to the exemplary drawings.

7A to 7J illustrate an elastic membrane 40, a piezoelectric actuator 50, a reservoir 23, and an upper pressure chamber 22 on the upper base substrate 20 in the method of manufacturing the piezoelectric droplet spray head according to the present invention. ) Are cross-sectional views for explaining the step of forming.

7A to 7C illustrate a step of forming the elastic film 40 including the silicon oxide film 41 and the silicon nitride film 42 on the upper base substrate 20.

First, referring to FIGS. 7A and 7B, as described above, by preparing an upper base substrate 20 made of a single crystal silicon substrate and causing the upper base substrate 20 to cause a chemical reaction by thermal energy in a low pressure reaction vessel. A silicon oxide film and a silicon nitride film are sequentially formed using a deposition method such as low pressure chemical vapor deposition (LPCVD), which is a deposition method for minimizing residual stress.

Next, as described above, the buffer film 43 made of a silicon oxide film for the stable formation of the piezoelectric actuator 50 on the upper surface of the upper base substrate 20 on which the silicon oxide film 41 and the silicon nitride film 42 are sequentially formed. The plasma is further formed by being deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD), a deposition method that accelerates ionization of gases by forming a plasma state.

Thus, the elastic film 40 and the buffer film 43 made of the silicon oxide film 41 and the silicon nitride film 42 are completed on the upper surface of the upper base substrate 20 through the aforementioned steps as shown in FIG. 7C.

7D to 7H illustrate a step of forming the piezoelectric actuator 50 on the upper surface of the upper base substrate 20 on which the elastic membrane 40 is formed. Referring to FIG. 7D, the lower electrode 51 and the piezoelectric material are deposited on the upper surface of the upper base substrate 20 on which the elastic film 40 is formed.

The lower electrode 51 can be obtained by sputtering electrode materials such as Ti, Pt, Au, and Al to a predetermined thickness, and the piezoelectric layer 52a is formed of a paste-like piezoelectric material using a sol-gel process. It is formed by drying or heat treatment after solution coating or screen printing by spin coating.

Various materials may be used as the material of the piezoelectric layer 52a. Preferably, a conventional lead zirconate titanate (PZT) ceramic material is used.

As such, although the piezoelectric layer 52a formed on the entire upper surface of the upper base substrate 20 is not shown in order to shape only the necessary portion to be used as the piezoelectric film 52, a photoresist as a photosensitive masking material is formed on the surface of the piezoelectric layer 52a. After applying (PR, PhotoResist), a photomasking process is performed in which the piezoelectric layer 52a is exposed by developing except for a necessary portion to be used as the piezoelectric film 52.

Next, except for the portion to be formed of the piezoelectric film 52, the photoresist of the portion to be formed of the piezoelectric film 52 using the upper substrate 200 on which the piezoelectric layer 52a is exposed is etched in a predetermined depth. By patterning the piezoelectric layer 52a, a piezoelectric film 52 is formed in a portion selectively required as shown in FIG. 7E.

Etching at this time can increase ion density without increasing ion energy, and can apply directionality to ion particles, so that dry etching method using Inductively Coupled Plasma (ICP), which is widely used for dry etching of thin films, is used. It is preferably carried out by.

After forming the piezoelectric layer 52 by patterning the piezoelectric layer 52a, the lower electrode 51 is also subjected to the same photoresist coating, photosensitive and dry etching process as the piezoelectric layer 52 as described above. The lower electrode 51 is formed as shown in FIG. 7F by patterning to a desired shape.

Next, as described below, the upper electrode 53 and the lower electrode 51 formed on the upper surface of the piezoelectric film 52 are interlayers as insulating elements for maintaining an insulating state with each other to apply voltage to the piezoelectric film 52. Silicon dioxide (SiO 2) or other insulating material is used to form an interlayer dielectric (ILD).

Although not shown, the interlayer insulating layer 54 may form only the necessary portions as shown in FIG. 7G by using photoresist coating, photosensitive, and lift off processes.

Then, the upper electrode is formed using a photoresist to form a pattern to expose only the necessary portion, and then deposit the necessary material on the exposed portion, the material deposited on the photoresist afterwards is removed together when removing the photoresist A piezoelectric actuator 50 is formed on the upper elastic film 40 of the upper base substrate 20 as shown in FIG. 7H by using a lift off process so that only necessary materials remain to be deposited. .

7I and 7K are cross-sectional views illustrating an etching process for forming the pressure chamber 22 and the reservoir 23 in the upper base substrate 20. First, as shown in FIG. 7I, the elastic membrane 40 formed on the lower surface of the upper substrate 20 is removed by using reactive ion etching (RIE), and the lower surface of the upper substrate 20 is removed. The lower silicon oxide film 41 of 40 is used as an etch stop layer by dry etching by Deep Reactive Ion Etching (Deep-RIE) to partially protect the reservoir 23 on one side of the lower surface of the upper base substrate 20. The pressure chambers 22 may be simultaneously formed at positions corresponding to the piezoelectric actuators 50 on the other side as shown in FIG. 7J.

Meanwhile, the Deep RIE technology forms a high-density plasma and applies a strong electric field so that ionized ion radicals of the etching gas ionized by the plasma collide and etch with high physical force at a high speed toward the substrate to be etched. It is a technology that creates vertical through-path by applying an etch barrier to the side of periodically etched part without continuous etching to penetrate the substrate vertically, suppressing the side view and inducing etching only downward. . On the other hand, reactive ion etching (RIE) does not cause severe physical collisions due to strong electric fields, but chemical reactions are caused by radicals of the etching gas ionized by plasma, causing the material to be etched.

In order to remove the elastic layer 40 constituting the upper wall of the portion of the reservoir portion 23a formed under one side of the upper base substrate 20 by the above process, photoresist coating, photosensitive and reactive ion etching are used again. As described above, the upper substrate 200 having the pressure chamber 22, the reservoir 23, the elastic membrane 40, and the piezoelectric actuator 50 is completed.

8A through 8E are cross-sectional views illustrating a manufacturing step of the lower substrate 300 having the fluid injection part 60 and the flow path.

First, referring to FIG. 8A, the lower base substrate 30 based on the formation of the lower substrate 300 is preferably made of a single crystal silicon substrate similarly to the upper base substrate 20 described above. The silicon nitride film 34 is coated on the upper and lower surfaces of the lower base substrate 30 prepared as described above, and the silicon nitride film forms the flow path injection unit 60, the fluid flow path 31, and the flow path diffuser 33, which will be described later. It serves as an etch politics layer in the wet etching process.

The silicon nitride film 34 is dry etched by using photoresist coating, photosensitive and reactive ion etching as described above to form the fluid injection port 63 as shown in FIG. 8B.

The single crystal silicon exposed through the fluid injection port 63 formed on the bottom surface of the lower base substrate 30 through this process is used as the silicon nitride film 34 as an etching mask and anisotropic wet etching using an etching solution such as potassium hydroxide. A diffuser 62 in the form of a diffuser in which the cross-sectional area gradually increases toward the injection port 63 is formed as shown in Fig. 8C.

Subsequently, as shown in FIG. 8D, the lower base substrate 30 on which the fluid injection port 63 and the jet diffuser 62 are formed is coated with photoresist, photosensitive, and Deep-RIE, and is larger than the diameter of the fluid injection port 63. A fluid discharge port 61 having a small diameter is formed through the lower base substrate 30.

Next, in order to form the pressure chamber 22, the flow path diffuser 33, and the fluid flow path 31, the silicon nitride film 34 formed on the upper surface of the lower base substrate through photoresist coating, photosensitive and reactive ion etching. Areas corresponding to the lower pressure chamber 32a, the flow path diffuser 33, and the fluid passage 31 are etched.

Next, the upper portion of the lower base substrate 30 is wet-etched using the silicon nitride film 34 as an etch mask to expose the pressure chamber 22, the flow path diffuser 33, and the fluid flow path 31 to be formed. Single crystal silicon is etched to simultaneously form the pressure chamber 22, the flow path diffuser 33, and the fluid passage 31, thereby completing the lower substrate 300.

Finally, as shown in FIG. 9, the upper substrate 200 and the lower substrate 300 manufactured by the above-described manufacturing process are directly bonded by heat treatment in a state in which a polymer bonding material is applied and then bonded or closely bonded to each other. Although it can be bonded by direct bonding (SDB: Silicon Direct Bonding), in the state where the silicon is exposed on the bonding surface of the upper and lower substrates, the gold thin film is coated on the bonding surfaces of both substrates, and the pressure is applied by bringing them into close contact with each other. It is preferable to adopt a method of inducing a fusion reaction between the silicon substrate and the gold thin film by applying a temperature at which an etchant reaction occurs, thereby completing the head.

While the invention has been described and illustrated in connection with a preferred embodiment for illustrating the principles of the invention, the invention is not limited to the construction and operation as shown and described as such. Rather, it will be apparent to those skilled in the art that many changes and modifications to the present invention are possible without departing from the spirit and scope of the appended claims. Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention.

Through the above configuration and fabrication step, the present invention provides a simple droplet ejection head structure and its manufacturing method by implementing the head structure using only two silicon substrates without using a sacrificial layer.

In addition, the present invention provides a flow path structure capable of inducing a smooth flow and injection in the head structure by introducing a diffuser structure to the flow path and the fluid injection portion to improve the injection performance of the injection target material in the internal structure of the droplet injection head and Provide an injection structure.

Claims (8)

An upper substrate through which a reservoir 23 into which ink is introduced and stored at one side and a pressure chamber 22 connected to the reservoir 23 and staying before the fluid introduced from the reservoir 23 is discharged are penetrated to one side and the other side, respectively. 200; The fluid discharge port 61 and the fluid discharge port 61 connected to the pressure chamber 22 and the fluid are injected, and have a diameter larger than that of the fluid discharge port 61 and the fluid discharge port 61 and the fluid injection port 63. It is connected to the fluid ejection port 60 consisting of the injection diffuser 62 is gradually increased in cross-sectional area from the fluid discharge port 61 toward the fluid injection port 63, and the reservoir 23 of the upper substrate 200 A fluid passage 31 connected to the fluid passage 31 and a fluid passage 31 connected to the fluid passage 31 and the pressure chamber 22 and having an increased cross-sectional area from the fluid passage 31 toward the pressure chamber 22. A lower substrate 300 formed of; And Piezoelectric actuator 50 that is integrally formed on the upper surface of the pressure chamber 22 of the upper substrate 200 to change the volume of the pressure chamber 22 by bending deformation to provide a discharge pressure to the fluid in the pressure chamber 22 It is provided, including the lower substrate 300 and the piezoelectric actuator 50, the microscopic precision droplet injection head using a piezoelectric method, characterized in that the upper substrate 200 is formed to be bonded to each other. The method of claim 1, The upper portion of the pressure chamber 22 of the upper substrate 200 is a silicon oxide film 41 and the silicon nitride film 42 is sequentially deposited, the elastic film 40 is bent deformation by driving the piezoelectric actuator 50 Ultra-precision droplet ejection head using a piezoelectric method characterized in that the role of. The method of claim 2, Ultra-fine precision droplet injection head using a piezoelectric method characterized in that it further comprises a buffer film (43) formed by forming a silicon oxide film on the upper surface of the elastic film (40) again. Preparing an upper base substrate 20 and a lower base substrate made of single crystal silicon; An elastic film forming step of forming an elastic film 40 that is easily bent and deformed on an upper surface of the upper base substrate 20; and a piezoelectric for providing a pressure for discharging fluid on the upper surface of the upper base substrate 20; A piezoelectric actuator forming step of forming an actuator 50; and a pressure chamber 22 formed on one side of the upper base substrate 20 corresponding to the position of the piezoelectric actuator 50, and the fluid flows into and stored on the other side. A pressure chamber for forming the reservoir 23 and a reservoir forming step; an upper substrate 200 manufacturing step consisting of: and A manufacturing step of forming a lower substrate (300) through which the fluid spray unit (60) penetrated through the lower substrate and the upper surface of the lower substrate are formed by an etching process; And And a bonding step of forming a droplet ejection head by bonding the upper substrate 200 and the lower substrate 300 to each other. A method of manufacturing a microscopic precision droplet ejection head using a piezoelectric method, characterized in that it comprises a. The method of claim 4, wherein The pressure chamber and the reservoir forming step is a method of manufacturing a microscopic precision droplet injection head using a piezoelectric method characterized in that for forming the pressure chamber and the reservoir using the Deep-RIE etching technology and RIE etching technology. The method of claim 4, wherein The fluid spraying part (60), the flow path diffuser (33) and the fluid flow path (31) on the upper surface of the lower base substrate is a microscopic precision droplet injection head manufacturing method using a piezoelectric method, characterized in that formed simultaneously by the etching process. The method of claim 4, wherein The spray diffuser 62 of the fluid injection unit 60 is formed by anisotropic wet etching to realize a diffuser shape in which the cross-sectional area is gradually increased with respect to the injection direction of the fluid. Method of manufacturing the head. The method of claim 4, wherein The fluid ejection opening (61) of the fluid ejection unit 60 is a method of manufacturing a microscopic precision droplet ejection head using a piezoelectric method, characterized in that formed through the lower substrate 300 by Deep-RIE etching technology.

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