KR100773566B1 - Damper of inkjet head and method of forming the same - Google Patents

Abstract

A damper of an ink-jet head and a method for forming the same are provided to simplify the process by forming a first damper, a manifold, and a restrictor by using one dry etching process. A damper of an ink-jet head connecting a plurality of pressure chambers and a plurality of nozzles includes a first damper(126a), a second damper(126b), and a third damper(126c). The upper end of the first damper is connected to the plurality of pressure chambers. The second damper is connected to the lower end of the first damper. The upper end of the third damper is connected to the second damper and the lower end thereof is connected to the plurality of nozzles. The cross-section of the second damper becomes wider as it goes from the lower end of the first damper toward the third damper. The cross-section of the third damper becomes narrower as it goes from the upper end thereof toward the lower end thereof.

Description

Damper of inkjet head and method of forming the same

1 is an exploded perspective view showing a specific example of a conventional piezoelectric inkjet head.

FIG. 2 is a vertical cross-sectional view illustrating a connection structure between the damper and the nozzle illustrated in FIG. 1.

3 is an exploded perspective view showing a partially cut inkjet head with a damper according to a preferred embodiment of the present invention.

4 is a vertical cross-sectional view of the assembled state of the inkjet head along the line AA ′ shown in FIG. 3.

5 is a view showing a result of simulating the velocity vector of the ink passing through the damper according to the present invention.

6A through 6E are diagrams illustrating steps of forming a first damper and a second damper on an intermediate substrate.

7A to 7E are diagrams illustrating steps of forming a third damper and a nozzle on a lower substrate.

<Explanation of symbols for main parts of the drawings>

110 ... Top substrate 112 ... Ink inlet

116 Pressure chamber 120 Intermediate substrate

122 ... Manifold 124 ... Lister

126 ... damper 126a ... first damper

126b ... second damper 126c ... third damper

130 Bottom substrate 138 Nozzle

150 Piezoelectric actuator 151 Bottom electrode

152 Piezoelectric Film 153 Upper Electrode

The present invention relates to an inkjet head, and more particularly, to a damper for connecting a nozzle and a pressure chamber of an inkjet head and a method of forming the same.

In general, an inkjet head is an apparatus for ejecting a small droplet of printing ink to a desired position on a recording medium to print an image of a predetermined color. Recently, such inkjet heads are used in flat panel display fields such as liquid crystal displays (LCDs), organic light emitting diodes (OLEDs), and plasma display panels (PDPs), metal wiring and resistors, and the like. It is expanding its application scope to include printed circuit board (PCB) and semiconductor packaging fields.

The inkjet head may be classified into two types according to the ink ejection method. One is a heat-driven inkjet head which generates bubbles in the ink by using a heat source and discharges the ink by the expansion force of the bubbles. The other is applied to the ink by deformation of the piezoelectric body using a piezoelectric body. It is a piezoelectric inkjet head which discharges ink by losing pressure.

1 illustrates a piezoelectric inkjet head disclosed in Korean Patent Laid-Open Publication No. 2003-0050477 (US Patent Publication No. 2003-0112300). 2 illustrates a connection structure between the damper and the nozzle illustrated in FIG. 1.

1 and 2 together, the conventional inkjet head has a structure in which three silicon substrates 30, 40, and 50 are stacked and bonded. A plurality of pressure chambers 32 having a predetermined depth are formed on the bottom surface of the upper substrate 30 among the three substrates 30, 40, and 50. An ink inlet 31 connected to an ink reservoir (not shown) is formed through the upper substrate 30. The plurality of pressure chambers 32 are arranged in two rows on both sides of the manifold 41 formed on the intermediate substrate 40. In addition, a piezoelectric actuator 60 is provided on the upper surface of the upper substrate 30 to provide a driving force for ejecting ink to each of the plurality of pressure chambers 32. The intermediate substrate 40 is provided with a manifold 41 connected to the ink inlet 31, and a restrictor 42 connected to each of the plurality of pressure chambers 32 on both sides of the manifold 41. Is formed. In addition, a plurality of first dampers 43 vertically penetrate the intermediate substrate 40 at positions corresponding to the plurality of pressure chambers 32. In addition, a plurality of second dampers 53 connected to the plurality of first dampers 43 are formed on an upper side of the lower substrate 50, and a plurality of second dampers 53 are formed on a lower side of the lower substrate 50. A plurality of nozzles 51 connected to the two dampers 53 are formed.

In the conventional inkjet head having the above-described configuration, the first damper 43 is formed to have a circular cross section by dry etching so as to vertically penetrate the intermediate substrate 40. The second damper 53 is formed by wet etching the upper surface of the lower substrate 50 to a predetermined depth. The second damper 53 has a rectangular cross-sectional shape, the sides of which are inclined by anisotropic wet etching characteristics. According to the etching method described above, the first damper 43 is referred to as a dry damper, and the second damper 53 is referred to as a wet damper.

However, as shown in FIG. 2, the length of one side of the second damper 53 is smaller than the diameter of the first damper 43, and thus, between the first damper 43 and the second damper 53. A stepped portion is formed. The bubble 9 contained in the ink may be trapped in the stepped portion, and the bubble 9 trapped in the stepped portion may cause variation in the volume of ink droplets discharged through the nozzle 51, The nozzle 51 may be blocked to cause a problem that makes it impossible to discharge the ink droplets.

In addition, the first damper 43 and the manifold 41 are formed on the intermediate substrate 40, but the depths of the first dampers 43 and the manifold 41 are different from each other. In other words, a portion of the first damper 43 is formed to a predetermined depth from the upper surface of the intermediate substrate 40 by the primary dry etching, and then the remaining portion of the first damper 43 is formed by the secondary dry etching. The manifold 41 is formed. As described above, in order to form the conventional first damper 43 and the manifold 41, not only two dry etching and two masks are required, but also the first damper 43 is provided by two dry etching processes. There is also a problem in that the manifold 41 is misaligned.

In addition, the first damper 43 is formed to penetrate the intermediate substrate 40. At this time, dry etching is performed while a silicon oxide film is formed on the bottom surface of the intermediate substrate 40. Therefore, if the dry etching time is not accurately controlled, the lower end portion of the first damper 43 is overetched to be inclined, thereby causing a problem in that the lower end portion is widened. As such, when the lower end of the first damper 43 becomes wider, the stepped portion becomes larger and the likelihood of a bubble trap is increased. Therefore, in order to prevent such a problem, there is an inconvenience in that etching and inspection must be repeated two or more times.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and an object thereof is to provide a damper of an ink jet head and a method of forming the inkjet head, which can prevent bubble traps and simplify the forming process.

The damper of the ink jet head according to the present invention for achieving the above technical problem,

In the damper of the inkjet head connecting the plurality of pressure chambers and the plurality of nozzles, respectively,

A first damper having an upper end connected to each of the plurality of pressure chambers; A second damper connected to a lower end of the first damper; An upper end portion connected to the second damper and a lower end portion connected to each of the plurality of nozzles; a third damper;

The second damper is characterized in that the cross-sectional area is gradually widened from the lower end of the first damper toward the third damper, and the third damper is gradually narrowed while going from the upper end to the lower end.

In the present invention, it is preferable that the first damper has a circular cross section of a constant diameter, and the second damper and the third damper each have a rectangular cross section and sloped sides.

In the present invention, the maximum length of one side of the rectangular cross section of each of the second damper and the third damper is preferably larger than the diameter of the first damper. In addition, it is preferable that the size of each rectangular cross section is substantially the same in the plane where the second damper and the third damper meet.

In the present invention, the first damper may be formed by dry etching, and the second damper and third damper may be formed by wet etching.

In addition, the method for forming a damper of an ink jet head according to the present invention for achieving the above technical problem,

In connecting a plurality of pressure chambers and a plurality of nozzles, respectively, in the method for forming a damper of the inkjet head comprising a first damper, a second damper and a third damper,

(A) preparing a first substrate and a second substrate; (B) wet etching the bottom surface of the first substrate to a predetermined depth to form the second damper; (C) dry etching the upper surface of the first substrate to form the first damper having an upper end connected to each of the plurality of pressure chambers and a lower end connected to the second damper; And (d) wet etching the upper surface of the second substrate to a predetermined depth to form the third damper having an upper end connected to the second damper and a lower end connected to each of the plurality of nozzles. It features.

In the present invention, the second damper is formed such that its cross-sectional area gradually widens from the lower end of the first damper toward the third damper, and the third damper is formed such that its cross-sectional area is gradually narrowed from its upper end toward the lower end. It is preferable to be.

In the present invention, the first damper is formed to have a circular cross section of a constant diameter, the second damper and the third damper may be formed to have a rectangular cross section and inclined sides, respectively. In addition, the maximum length of one side of the rectangular cross section of each of the second damper and the third damper is preferably formed to be larger than the diameter of the first damper. In addition, it is preferable that the rectangular cross sections of the second damper and the third damper are formed to have substantially the same size on the bottom surface of the first substrate and the top surface of the second substrate.

In the present invention, in the step (c), the manifold and the restrictor may be simultaneously formed on the upper surface of the first substrate together with the first damper by one dry etching.

In the present invention, the first substrate and the second substrate are preferably single crystal silicon wafers.

In the present invention, the wet etching may be performed using tetramethyl ammonium hydroxide (TMAH) or potassium hydroxide (KOH) as an etchant for silicon. The dry etching may be performed by reactive ion etching (RIE) using inductively coupled plasma (ICP).

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals refer to like elements, and the size of each element may be exaggerated for clarity and convenience of description. In addition, when one layer is described as being on top of a substrate or another layer, the layer may be present over and in direct contact with the substrate or another layer, with a third layer in between.

3 is an exploded perspective view showing a partially cut inkjet head with a damper according to a preferred embodiment of the present invention, Figure 4 is a vertical cross-sectional view of the assembled state of the inkjet head along the line AA 'shown in FIG. .

3 and 4 together, the inkjet head is provided on the flow path forming plates (110, 120, 130) and the flow path forming plates (110, 120, 130) on which the ink flow paths are formed to provide a driving force for ejecting ink. A piezoelectric actuator 150 is provided.

The flow path forming plates 110, 120, and 130 may include an upper substrate 110, an intermediate substrate 120, and a lower substrate 130, and the piezoelectric actuator 150 may be disposed on an upper surface of the upper substrate 110. Can be formed. As the upper substrate 110, the intermediate substrate 120, and the lower substrate 130, a silicon substrate widely used in the manufacture of a semiconductor integrated circuit may be used.

The ink flow paths formed in the flow path forming plates 110, 120, and 130 are ink inlets 112 through which ink flows from an ink reservoir (not shown), and a passage through which ink flows through the ink inlets 112 passes. A manifold 122, a plurality of pressure chambers 116 filled with ink supplied from the manifold 122, and a plurality of nozzles 138 for ejecting ink from the plurality of pressure chambers 116. Include. The ink flow path further includes a damper 126 that connects the plurality of chambers 116 and the plurality of nozzles 133 as features of the present invention, respectively. In addition, the ink flow path may further include a plurality of restrictors 124 connecting each of the plurality of chambers 116 to the manifold 122.

Hereinafter, the configuration of the ink flow path will be described in detail.

The ink inlet 112 is a passage through which ink enters from an ink reservoir (not shown) and may be formed to vertically penetrate the upper substrate 110. As shown in FIG. 3, the ink inlet 112 may be formed at a position corresponding to one end of the manifold 122 to be described later. On the other hand, the ink inlet 112 may be formed at a position corresponding to the middle portion of the manifold 122, it may also be formed long along the longitudinal direction of the manifold (122).

The manifold 122 may be formed at a predetermined depth on the upper surface of the intermediate substrate 120, and may have a long shape in one direction.

The plurality of pressure chambers 116 may be formed at a predetermined depth on the bottom surface of the upper substrate 110. A portion of the upper substrate 110 that forms the upper wall of each of the plurality of pressure chambers 116 serves as the diaphragm 117 vibrating by the driving of the actuator 150. The plurality of pressure chambers 116 may be arranged in one row on one side of the manifold 122, each of which may have a shape of a longer rectangular parallelepiped in the flow direction of the ink. Meanwhile, the plurality of pressure chambers 116 may be arranged in two rows on both sides of the manifold 122.

The piezoelectric actuator 150 may be formed on an upper surface of the upper substrate 110. In addition, an insulating film 118 may be formed between the upper substrate 110 and the piezoelectric actuator 150. When the upper substrate 110 is a silicon substrate, a silicon oxide film may be used as the insulating film 118. The piezoelectric actuator 150 may include a lower electrode 151 serving as a common electrode, a piezoelectric film 152 deformed by application of a voltage, and an upper electrode 153 serving as a driving electrode. . The lower electrode 151 may be formed on the entire surface of the insulating layer 118, and may be formed of a conductive metal material layer. The piezoelectric film 152 is formed on the lower electrode 151 and is disposed to be positioned above each of the plurality of chambers 116. The piezoelectric film 152 may be made of a piezoelectric material, preferably a lead zirconate titanate (PZT) ceramic material. The piezoelectric film 152 is deformed by the application of a voltage, thereby deforming the diaphragm 117 that forms the upper wall of the pressure chamber 116. The upper electrode 153 is formed on the piezoelectric film 152 and serves as a driving electrode for applying a voltage to the piezoelectric film 152.

In addition, a plurality of restrictors 124 may be formed in the intermediate substrate 120 to connect each of the plurality of pressure chambers 116 with the manifold 122. Each of the plurality of restrictors 124 is formed to have a cross-sectional area smaller than that of the chamber 116 so as to suppress backflow of ink. Each of the plurality of restrictors 124 may have a cross section having a substantially “T” shape. Meanwhile, the plurality of restrictors 124 may be formed in various shapes different from those shown in FIG. 3.

The damper 126, which is a feature of the present invention, is a passage connecting the plurality of pressure chambers 116 and the plurality of nozzles 138, respectively, and includes a first damper 126a formed on an upper side of the intermediate substrate 120. A second damper 126b formed at a lower side of the intermediate substrate 120 to be connected to the first damper 126a, and a third damper 126c formed at an upper surface of the lower substrate 130 to be connected to the second damper 126b. ).

In detail, the first damper 126a is formed to a predetermined depth from an upper surface of the intermediate substrate 120 such that an upper end thereof is connected to each of the plurality of pressure chambers 116. The first damper 126a is formed to have a circular cross section of a constant diameter by dry etching. For example, the first damper 126a may have a diameter of 200 μm to 300 μm, and preferably may have a diameter of about 250 μm. In addition, when the thickness of the intermediate substrate 120 is about 250 μm, the first damper 126a may have a depth of about 200 μm.

The second damper 126b is formed to a predetermined depth from the bottom surface of the intermediate substrate 120 and is connected to the lower end of the first damper 126a. The second damper 126b has a rectangular cross-sectional shape, and side surfaces thereof are inclined by anisotropic wet etching characteristics. The maximum length of one side of the rectangular cross section of the second damper 126b is larger than the diameter of the first damper 126a. For example, when the diameter of the first damper 126a is about 250 μm, the second damper 126b preferably has a rectangular cross section having a maximum length of about 300 μm. That is, the second damper 126b has a shape in which its cross-sectional area gradually widens downward from the lower end of the first damper 126a. In addition, when the thickness of the intermediate substrate 120 is about 250 μm, the second damper 126b may have a depth of about 50 μm.

An upper end of the third damper 126c is connected to the second damper 126b, and a lower end thereof is connected to each of the plurality of nozzles 138. The third damper 126c is formed to a predetermined depth from an upper surface of the lower substrate 130 at a position connected to the second damper 126b. The third damper 126c also has a rectangular cross-sectional shape, and side surfaces thereof are inclined by anisotropic wet etching characteristics. That is, the third damper 126c has a shape in which its cross-sectional area gradually decreases from the upper surface of the lower substrate 130 to the lower side. The size of the rectangular cross section of the third damper 126c is formed to be substantially the same as the size of the rectangular cross section of the second damper 126b. Therefore, in the state where the intermediate substrate 120 and the lower substrate 130 are bonded to each other, the third damper 126c and the second damper 126b coincide with each other. In addition, when the thickness of the lower substrate 130 is about 150 μm, the third damper 126c may have a depth of about 100 μm.

Each of the plurality of nozzles 138 is formed to vertically penetrate the lower substrate 130 from the bottom surface of the third damper 126c. Each of the plurality of nozzles 138 may have a shape of a circular hole having a constant diameter, for example, a diameter of about 28 μm by dry etching. In addition, when the thickness of the lower substrate 130 is about 150 μm, the nozzle 138 may have a depth of about 50 μm.

As described above, in the present invention, the dampers 126 connecting the plurality of pressure chambers 116 and the plurality of nozzles 138, respectively, include a first damper 126a formed by dry etching and a wet type. The second damper 126b is formed by etching, and the third damper 126c is also formed by wet etching. In addition, since the second damper 126b and the third damper 126c have a cross-sectional area larger than that of the first damper 126a, a step is formed in the damper 126 to prevent the flow of ink unlike the prior art. It doesn't work. Therefore, the problem that bubbles are trapped inside the damper 126 does not occur, and thus, deterioration of ink discharge characteristics due to bubble traps can be prevented.

5 is a view showing a result of simulating the velocity vector of the ink passing through the damper according to the present invention.

Referring to FIG. 5, the speed of the ink droplets ejected through the nozzle is approximately 3.3 m / s, and the speed of the ink at the portion where the second damper and the third damper meet, that is, the portion indicated by the dotted line, is approximately 0.1 m / s. It is as follows. In this way, the speed of the ink in the portion where the cross-sectional area where the second damper and the third damper meet is widened is very low, and does not significantly affect the overall flow rate of the ink in the damper.

Hereinafter, a method of forming a damper of an ink jet head according to the present invention having the above-described configuration will be described.

6A through 6E are diagrams illustrating steps of forming a first damper and a second damper on an intermediate substrate.

First, referring to FIG. 6A, a first substrate to be used as the intermediate substrate 120 of the inkjet head is prepared. The first substrate 120 may be made of a single crystal silicon wafer. This is because silicon wafers widely used in the manufacture of semiconductor devices can be used as they are and are effective for mass production. The prepared first substrate 120 is dry or wet oxidized to form silicon oxide films 171a and 171b on the top and bottom surfaces of the first substrate 120. Subsequently, the silicon oxide film 171b formed on the bottom surface of the first substrate 120 is dry or wet etched to form a first opening 181 for forming a second damper (126b of FIG. 6B). At this time, the first opening 181 may be formed in a circular shape having a diameter of about 280㎛.

Next, as shown in FIG. 6B, the bottom surface of the first substrate 120 exposed through the first opening 181 is wet etched to a predetermined depth. In this case, the wet etching may be performed using, for example, tetramethyl ammonium hydroxide (TMAH) or potassium hydroxide (KOH) as an etchant for silicon. Then, a second damper 126b having side surfaces inclined by anisotropic wet etching characteristics is formed on the bottom surface of the first substrate 120. After the second damper 126b is formed, the silicon oxide films 171a and 171b remaining on the surface of the first substrate 120 are removed by wet etching or the like.

Next, as illustrated in FIG. 6C, the first substrate 120 is again dry or wet oxidized to form silicon oxide films 172a and 172b on the top and bottom surfaces of the first substrate 120. At this time, the silicon oxide film 172a is formed on side surfaces of the second damper 126b formed on the bottom surface of the first substrate 120. Subsequently, the silicon oxide film 172a formed on the upper surface of the first substrate 120 is dry or wet etched to form a second opening 182 for forming a first damper (126a in FIG. 6D). At this time, the second opening 182 may be formed in a circular shape having a diameter of about 250 ~ 280㎛. In addition, a third opening 183 for forming a manifold (122 in FIG. 6D) and a restrictor (124 in FIG. 6D) is also formed in the silicon oxide film 172a together with the second opening 182.

Next, as shown in FIG. 6D, the upper surface of the first substrate 120 exposed through the second opening 182 and the third opening 183 is etched to a predetermined depth. In this case, etching of the first substrate 120 may be performed by a dry etching method such as reactive ion etching (RIE) using an inductively coupled plasma (ICP). Then, a first damper 126a having a circular cross section of a constant diameter is formed on the first substrate 120, and a lower end portion of the first damper 126a is formed on the side surfaces of the second damper 126b. Blocked by). The manifold 122 and the restrictor 124 are formed to a predetermined depth from the upper surface of the first substrate 120 together with the first damper 126a. In this case, as shown in FIG. 3, since the cross-sectional area of the restrictor 124 is narrower than that of the manifold 122, the restrictor 124 is formed to be slightly shallower than the manifold 122.

Subsequently, when the silicon oxide films 172a and 172b remaining on the surface of the first substrate 120 are removed by wet etching or the like, as illustrated in FIG. 6E, the first dampers 126a and the second dampers 126b may be removed. Are connected to each other.

As described above, according to the damper forming method of the present invention, since the first damper 126a, the manifold 122, and the restrictor 124 can be formed together by one dry etching process, the process is simplified. There is an advantage. In addition, since only one mask is required to form the first damper 126a, the manifold 122, and the restrictor 124, there is an advantage that misalignment does not occur between them. Although, in the present invention, the process of forming the second damper 126b on the bottom surface of the second substrate 120 is added as compared to the prior art, the process of forming the second damper 126b is a batch method. Because of this possible wet etching process, the process cost and time can be reduced compared to the dry etching process performed on the individual wafers.

In addition, since the first dampers 126a and the manifold 122 are formed to have substantially the same depth, there is almost no problem that the first dampers 126a are over-etched. If the first damper 126a is overetched so that its lower end is inclinedly widened, the lower end of the first damper 126a may continue to the inclined side surfaces of the second damper 126b without stepping. Therefore, the process can be completed by only one etching and one inspection.

7A to 7E are diagrams illustrating steps of forming a third damper and a nozzle on a lower substrate.

First, referring to FIG. 7A, a second substrate to use the lower substrate 130 of the inkjet head is prepared. The second substrate 130 may also be made of a single crystal silicon wafer. The prepared second substrate 130 is dry or wet oxidized to form silicon oxide films 173a and 173b on the top and bottom surfaces of the second substrate 130. Subsequently, the silicon oxide film 173a formed on the upper surface of the second substrate 130 is dry or wet etched to form a fourth opening 184 for forming a third damper (126c in FIG. 7B). In this case, the fourth opening 184 may be formed in a circular shape having a diameter of about 280 μm similarly to the second opening 182 described above. In addition, in order to make the size of the second damper 126b and the third damper 126c the same, the size of the second opening 182 and the fourth opening 184 is the same.

Next, as shown in FIG. 7B, the upper surface of the second substrate 130 exposed through the fourth opening 184 is wet etched to a predetermined depth, for example, about 100 μm. In this case, the wet etching may be performed using, for example, tetramethyl ammonium hydroxide (TMAH) or potassium hydroxide (KOH) as an etchant for silicon. Then, a third damper 126c having inclined side surfaces and a flat bottom surface is formed on the upper surface of the second substrate 130 by anisotropic wet etching characteristics. After the third damper 126c is formed, the silicon oxide films 173a and 173b remaining on the surface of the second substrate 130 are removed by wet etching or the like.

Next, as shown in FIG. 7C, the second substrate 130 is again dry or wet oxidized to form silicon oxide films 174a and 174b on the top and bottom surfaces of the second substrate 130. At this time, the silicon oxide film 174a is formed on the side surfaces and the bottom surface of the third damper 126c formed on the upper surface of the second substrate 130. Subsequently, the silicon oxide film 174b formed on the bottom surface of the second substrate 130 is dry or wet etched to form a fifth opening 185 for forming the nozzle 138 of FIG. 7D. In this case, the fifth opening 185 may be formed in a circular shape having a diameter of about 28 μm.

Next, as shown in FIG. 7D, the bottom surface of the second substrate 130 exposed through the fifth opening 185 is etched to a predetermined depth. In this case, etching of the second substrate 130 is performed by a dry etching method such as reactive ion etching (RIE) using an inductively coupled plasma (ICP). Then, a nozzle 138 having a circular cross section of a constant diameter is formed on the second substrate 130.

Subsequently, when the silicon oxide films 174a and 174b remaining on the surface of the second substrate 130 are removed by wet etching or the like, as illustrated in FIG. 7E, the third damper 126c and the nozzle 138 are connected to each other. do.

As described above, the silicon substrate is directly bonded to the first substrate 120 on which the first damper 126a and the second damper 126b are formed, and the second substrate 130 on which the third damper 126c and the nozzle 138 are formed. Bonding is performed by the method (SDB: Silicon Direct Bonding). Then, as shown in FIG. 4, the first damper 126a, the second damper 126b, and the third damper 126c are sequentially connected to form the damper 126 according to the present invention.

While the preferred embodiments of the present invention have been described in detail, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the appended claims.

As described above, according to the present invention, since the problem of trapping bubbles inside the damper does not occur, there is an advantage of preventing the deterioration of ink discharge characteristics due to the bubble trap. In addition, since the first damper, the manifold and the restrictor formed on the intermediate substrate can be formed together by one dry etching process, the process is simplified. In addition, since only one mask is required to form the first damper, the manifold, and the restrictor, there is an advantage that no misalignment occurs between them.

Claims (15)

In the damper of the inkjet head connecting the plurality of pressure chambers and the plurality of nozzles, respectively, A first damper having an upper end connected to each of the plurality of pressure chambers; A second damper connected to a lower end of the first damper; An upper end portion connected to the second damper and a lower end portion connected to each of the plurality of nozzles; a third damper; The second damper has a cross-sectional area that gradually increases from the lower end of the first damper toward the third damper, and the third damper gradually narrows its cross-sectional area from the upper end to the lower end thereof. . The method of claim 1, The first damper has a circular cross section of a constant diameter, And the second damper and the third damper each have a rectangular cross section and inclined side surfaces. The method of claim 2, And a maximum length of one side of a rectangular cross section of each of the second damper and the third damper is larger than the diameter of the first damper. The method of claim 2, The damper of the ink jet head, characterized in that the size of each rectangular cross-section in the plane where the second damper and the third damper meet. The method according to any one of claims 1 to 4, And the first damper is formed by dry etching, and the second damper and third damper are formed by wet etching. The method according to any one of claims 1 to 4, The first damper is formed to a predetermined depth from the upper surface of the first substrate, the second damper is formed to a predetermined depth from the bottom surface of the first substrate is connected to the lower end of the first damper, the third damper is the The damper of the inkjet head, characterized in that formed in a predetermined depth from the upper surface of the second substrate bonded to the bottom surface of the first substrate. In connecting a plurality of pressure chambers and a plurality of nozzles, respectively, in the method for forming a damper of the inkjet head comprising a first damper, a second damper and a third damper, (A) preparing a first substrate and a second substrate; (B) wet etching the bottom surface of the first substrate to a predetermined depth to form the second damper; (C) dry etching the upper surface of the first substrate to form the first damper having an upper end connected to each of the plurality of pressure chambers and a lower end connected to the second damper; And (D) wet etching the upper surface of the second substrate to a predetermined depth, forming a third damper having an upper end connected to the second damper and a lower end connected to each of the plurality of nozzles. The damper formation method of the inkjet head made into. The method of claim 7, wherein The second damper is formed so that the cross-sectional area gradually widens from the lower end of the first damper toward the third damper, and the third damper is formed so that its cross-sectional area is gradually narrowed from the upper end to the lower end. Method for forming dampers in inkjet heads. The method of claim 8, The first damper is formed to have a circular cross section of a constant diameter, And the second damper and the third damper are formed to have rectangular cross sections and inclined side surfaces, respectively. The method of claim 9, And a maximum length of one side of a rectangular cross section of each of the second damper and the third damper is larger than a diameter of the first damper. The method of claim 9, And a rectangular cross-section of each of the second damper and the third damper on the bottom surface of the first substrate and the top surface of the second substrate is substantially the same size. The method according to any one of claims 7 to 11, In the step (c), the manifold and the restrictor are simultaneously formed on the upper surface of the first substrate together with the first damper by one dry etching. The method according to any one of claims 7 to 11, And the first substrate and the second substrate are single crystal silicon wafers. The method according to any one of claims 7 to 11, The wet etching is a method of forming a damper of an inkjet head, characterized in that it is carried out using tetramethyl ammonium hydroxide (TMAH) or potassium hydroxide (KOH) as an etchant for silicon. The method according to any one of claims 7 to 11, And the dry etching is performed by reactive ion etching (RIE) using an inductively coupled plasma (ICP).

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