KR100421216B1 - Bubble-jet type ink-jet print head and manufacturing method thereof - Google Patents

Abstract

A bubble jet inkjet print head and a method of manufacturing the same are disclosed. The disclosed inkjet printhead is filled with ink to be discharged on a surface thereof, and has a substantially hemispherical ink chamber and a manifold for supplying ink to the bottom thereof, and an ink connecting the ink chamber and the manifold to the bottom of the ink chamber. The heater plate is formed by integrally forming a channel, a nozzle plate formed on the substrate, and having a nozzle formed at a position corresponding to the central portion of the ink chamber, and a heater positioned on the nozzle plate and surrounding the nozzle. It is provided with an electrode for applying a current, it characterized in that the shape of the electrode and the heater is variously modified so that the current flows uniformly.

Description

Bubble-jet type ink-jet print head and manufacturing method thereof {Bubble-jet type ink-jet print head and manufacturing method}

The present invention relates to an inkjet printhead, and more particularly, to a bubblejet inkjet printhead, a manufacturing method thereof, and an ink ejecting method.

Ink jet printers use a heat source to generate bubbles (bubbles) in the ink and discharge the ink by this force, using an electro-thermal transducer (bubble jet method), and a piezoelectric material. There is an electro-mechanical transducer in which ink is ejected by a volume change of ink caused by deformation of the piezoelectric body.

The ink jetting mechanism of the bubble jet method will be described with reference to FIGS. 1A and 1B as follows. When a current pulse is applied to the heater 12 made of the resistance heating element to the ink flow path 10 having the nozzle 11 formed therein, the heat generated by the heater 12 heats the ink 14 and bubbles in the ink flow path 10. 15 is generated and ink droplets 14 'are ejected by the force.

By the way, an ink jet print head having such a bubble jet ink ejecting portion must satisfy the following requirements.

First, the production should be as simple as possible, inexpensive to manufacture, and capable of mass production.

Second, in order to obtain clear picture quality, the generation of fine satellite droplets smaller than the main droplets following the main droplets to be discharged should be suppressed as much as possible.

Third, when ejecting ink from one nozzle or refilling the ink into the ink chamber after ejecting the ink, cross talk with other adjacent nozzles that do not eject ink should be suppressed as much as possible. To this end, it is necessary to suppress back flow of ink in the opposite direction of the nozzle during ink ejection. Another heater 13 is for this in FIGS. 1a and 1b.

Fourth, for high speed printing, the period of refilling after ink discharge should be as short as possible. In other words, the driving frequency must be high.

However, these requirements often conflict with each other, and the performance of the ink jet print head is in turn closely related to the structure of the ink chamber, the ink flow path and the heater, the resulting bubble formation and expansion, or the relative size of each element. have.

Accordingly, US Patent Nos. 4339762, US 4882595, US 5760804, US 4847630, US Pat. Microinjector with Virtual Chamber Neck ", IEEE MEMS '98, pp.57-62, various ink jet print heads have been proposed. However, the ink jet print heads of the structures set forth in these patents and documents are not entirely satisfactory, although some of the above requirements are satisfied.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide an inkjet print head having an improved structure that satisfies the aforementioned requirements.

1A and 1B are cross-sectional views showing a conventional bubble jet inkjet print head structure and an ink ejection mechanism;

2 is a schematic plan view of a bubble-jet inkjet printhead according to the present invention;

3 is an enlarged plan view of the ink ejecting unit according to the first embodiment of the present invention;

4 is a cross-sectional view showing a vertical structure of the ink ejecting portion viewed along the line C-C of FIG.

5 is a cross-sectional view showing a modification of the ink chamber of FIG. 4;

6 is an enlarged plan view of an ink ejecting unit according to a second exemplary embodiment of the present invention;

FIG. 7 is a cross-sectional view illustrating a vertical structure of the ink ejecting unit viewed along the line D-D of FIG. 6;

8 is a plan view showing an ink ejecting unit according to a third embodiment of the present invention;

9 is a cross-sectional view showing the vertical structure of the ink ejecting portion seen along the line E-E of FIG. 8;

10 is a plan view showing an ink ejecting unit according to a fourth embodiment of the present invention;

FIG. 11 is a cross-sectional view showing the vertical structure of the ink ejecting portion seen along the line F-F in FIG. 10;

12 is a plan view showing a printhead according to a fifth embodiment of the present invention;

FIG. 13 is a sectional view showing the vertical structure of the ink ejecting portion seen along the line G-G in FIG. 12;

14 is a cross-sectional view showing a modification of the ink ejecting portion shown in FIG. 12;

15 is a plan view showing an ink ejecting unit according to a sixth embodiment of the present invention;

16 is a plan view showing an ink ejecting unit according to a seventh embodiment of the present invention;

17 and 18 are cross-sectional views showing the ink ejection process of the ink ejection portion shown in FIG.

19 and 20 are cross-sectional views showing the ink ejection process in the ink ejection portion shown in FIG.

21 to 26 are cross-sectional views of a process of manufacturing an ink ejecting portion having an ink ejecting portion as shown in FIG. 4, taken along line A-A of FIG.

27 and 28 are cross-sectional views illustrating a process of manufacturing an ink ejecting portion having the ink ejecting portions shown in FIG. 5, taken along line AA of FIG.

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

3.ink ejection part 100 ... substrate

102 Manifold 104 Ink chamber

107 Ink Channel 108 Bubble Guide

110 Nozzle plate 120 Heater

130 Insulation layer 140, 141, 144, 147, 150, 170, 172 electrode 160,

160a ... Nozzle 190 ... Drop Guide

In order to achieve the above object, a bubble jet inkjet print head of the present invention is filled with ink to be discharged on a surface thereof, and has a substantially hemispherical ink chamber, and a manifold for supplying ink to the back surface, and the ink A substrate on which the ink channel connecting the ink chamber and the manifold is integrally formed at the bottom of the chamber, a nozzle plate laminated on the substrate and having a nozzle formed at a position corresponding to the central portion of the ink chamber, and positioned on the nozzle plate And a heater formed to surround the nozzle and an electrode electrically connected to the heater to apply a current to the heater.

According to the invention, the diameter of the ink channel is less than or equal to the diameter of the nozzle.

According to the present invention, a bubble and a droplet guide extending from the edge of the nozzle in the bottom direction of the ink chamber are formed.

According to the present invention, the heater is a doughnut-type, the electrode is formed of a first electrode formed along the outer edge of the heater one side is open, and a second electrode formed in a circular shape along the inner edge of the heater Bubble jet inkjet print head characterized in that.

According to the invention, the heater is a doughnut-shaped, the electrode is characterized in that the third electrode formed in a circular shape along the outer edge of the heater, and a fourth electrode formed in a circular shape along the inner edge of the heater .

According to the present invention, the heater is a doughnut-shaped, the lower surface of the heater is connected to the circular fifth electrode having a larger diameter than the heater, the upper surface of the heater has a circular sixth smaller than the heater It is characterized in that the electrode is connected.

According to the invention, the heater is a doughnut-shaped, the electrode is a circular seventh electrode formed along the outer edge of the heater, a circular eighth electrode formed along the inner edge of the heater, and the seventh electrode And a plurality of circular electrodes provided at predetermined intervals between the eighth electrode and the eighth electrode.

According to the invention, the heater has a "Ω" shape, the heater is formed in two stages, the electrode is characterized in that connected to both ends of the heater, respectively.

According to the present invention, the heater is formed to be inclined from the outside to the inside, and the electrode is characterized in that each connected to both ends of the heater.

According to the present invention, the heater has a "Ω" shape, and comprises a first heater and a second heater, wherein the first heater is larger in diameter than the second heater, and the first heater and the second heater are spaced a predetermined distance apart. It is characterized by that.

According to the invention, the heater has a rectangular shape, the electrode is characterized in that connected to each of the two corresponding points of the heater.

The method of manufacturing a bubble jet inkjet printhead of the present invention comprises the steps of forming a nozzle plate on a surface of a substrate, forming an annular heater on the nozzle plate, and supplying ink from the rear surface of the substrate to the surface of the substrate. Forming a manifold; forming an electrode electrically connected to the annular heater on the nozzle plate; and etching the nozzle plate to a diameter smaller than a diameter of the annular heater inside the annular heater. Forming an ink chamber having a diameter larger than that of the annular heater and having a substantially hemispherical shape, wherein the substrate is exposed by the nozzle to form the ink chamber. Forming an ink channel connecting the folds.

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

2 is a schematic plan view of a bubble jet inkjet print head according to an embodiment of the present invention.

Referring to FIG. 2, the print head according to the present invention has two rows of ink ejecting portions 3 arranged in a zigzag pattern on a substrate 100, electrically connected to each ink ejecting portions 3, and a wire is bonded. Bonding pads 20 are to be arranged. Although the ink ejecting portions 3 are arranged in two rows in the drawing, they may be arranged in one row or may be arranged in three or more rows to further increase the resolution. In the ink ejecting portion 3, manifolds 102 for supplying ink are formed, respectively. The manifold 102 is connected to an ink cartridge (not shown) to receive ink. In addition, the manifold 102 for supplying ink may be connected to each column. Meanwhile, although a print head using only one color ink is shown in the drawing, three or four groups of ink ejecting portions may be arranged for each color for color printing.

3 is an enlarged plan view of the ink ejecting unit according to the first exemplary embodiment of the present invention, and FIG. 4 is a cross-sectional view illustrating a vertical structure of the ink ejecting unit viewed along the line C-C of FIG.

3 and 4, the ink ejecting portion 3 according to the first embodiment of the present invention, first, the substrate 100, the ink chamber 104 in which ink is filled in the surface side is formed in a substantially hemispherical shape A manifold 102 for supplying ink to each ink chamber 104 is formed on the rear side thereof, and the ink chamber 104 and the manifold 102 are connected to the bottom center of the ink chamber 104. The ink channel 106 is formed integrally. Here, the substrate 100 is preferably made of silicon widely used in the manufacture of integrated circuits.

The ink channel 104 is shown to be smaller in diameter than the nozzle 160, but is not necessarily small. However, since the diameter of the ink channel 107 is an important factor affecting the backflow phenomenon in which ink is pushed toward the ink channel 107 during ink ejection and the refilling speed after ink ejection, the ink channel 106 is formed at the time of forming the ink channel 106. Its diameter needs to be finely controlled.

The nozzle plate 110 having the nozzles 160 formed on the surface of the substrate 100 forms an upper wall of the ink chamber 104. When the substrate 100 is made of silicon, the nozzle plate 110 may be formed of a silicon oxide film formed by oxidizing the silicon substrate 100, and may be formed of an insulating film such as a silicon nitride film deposited on the substrate 100.

The heater 120 is formed on the nozzle plate 110 in a donut shape surrounding the nozzle 160, and the electrode 141 includes a first electrode 142 and a second electrode 143. The heater 120 is made of a resistance heating element such as polycrystalline silicon or tantalum-aluminum alloy doped with impurities, and the first and second electrodes 142 and 143 for applying a pulsed current to the heater 120. ) Connects.

The first electrode 142 is formed along the outer edge of the heater 120, one side is open. The second electrode 143 is annular and is formed to surround the nozzle 160 along an inner edge of the heater 120. A lead 300 connected to the bonding pad 20 of FIG. 2 is connected to the first electrode 142 and the second electrode 143. The first electrode 142 and the second electrode 143 are generally made of the same material as the bonding pad (20 in FIG. 2) and the lead 300, for example, a metal such as aluminum or an aluminum alloy. At this time, the insulating layer 130 is interposed between the heater 120 and the electrode 140 to prevent the mutual contact at any place other than the connection point.

5 is a cross-sectional view showing a modification of the ink chamber of FIG. Referring to FIG. 5, the ink chamber 104a includes a droplet guide 190 extending from the edge of the nozzle 160a toward the ink chamber 104a and the nozzle plate 110 forming the upper wall of the ink chamber 104a. A few substrate materials remain around the lower droplet guide 190 to include the bubble guide 108.

6 is an enlarged plan view of the ink ejecting unit according to the second exemplary embodiment of the present invention, and FIG. 7 is a cross-sectional view illustrating a vertical structure of the ink ejecting unit along the line D-D shown in FIG. 3 and 4, the same reference numerals denote the same members having the same function.

6 and 7, the heater 120 is formed in a donut shape. The electrode 144 includes a third electrode 145 and a fourth electrode 146, and is formed on the heater 120. The first electrode 145 is formed in a circular shape forming a closed curve along the outer edge of the heater 120. The second electrode 146 is annular and is formed in a circular shape forming a closed curve along the inner edge of the heater 120. Current flowing through the third electrode 145 or the fourth electrode 146 flows through the heater 120 to the third electrode 145 or the fourth electrode 146. An insulating layer 130 is interposed between the electrodes 145 and 146 and the heater 146.

FIG. 8 is a plan view showing the ink ejecting portion according to the third embodiment of the present invention, and FIG. 9 is a sectional view showing the vertical structure of the ink ejecting portion along the line E-E shown in FIG. 3 and 4, the same reference numerals denote the same members having the same function.

8 and 9, the heater 120 is formed in a doughnut shape, and the electrode 147 is formed of the fifth electrode 148 and the sixth electrode 149. The fifth electrode 148 is annular and is formed on the lower surface of the heater 120. In this embodiment, the width of the fifth electrode 148 is greater than the width of the heater 120. It does not have to be large, but it can be the same or smaller. The sixth electrode 149 is annular and is formed on the upper surface of the heater 120, and the width thereof is preferably formed to be smaller than or equal to the width of the heater 120. An insulating layer 130 is interposed between the fifth electrode 148 and the sixth electrode 149 except for a portion connected to the heater 120 so as not to be in contact with each other. Accordingly, current flowing from the fifth electrode 148 or the sixth electrode 149 flows through the heater 120 to the sixth electrode 149 or the fifth electrode 148.

FIG. 10 is a plan view showing the ink ejecting section 3 according to the fourth embodiment of the present invention, and FIG. 11 is a sectional view showing the vertical structure of the ink ejecting section 3 along the FF line shown in FIG. to be. Here, the same reference numerals as in Figs. 3 and 4 denote the same members having the same function.

10 and 11, the heater 120 is donut-shaped, and the electrode 150 includes a seventh electrode 151, an eighth electrode 152, and a plurality of ninth electrodes 153. The seventh electrode 151 is formed along the outer edge of the heater 120, and the eighth electrode 152 is formed along the inner edge of the heater 120. In addition, a plurality of ninth electrodes 153 having an annular shape are formed on the heater 120 between the seventh electrode 151 and the eighth electrode 152. When the current flowing from the eighth electrode 152 reaches the ninth electrode 153, the ninth electrode 153 serves as a medium for flowing current. Therefore, uniform electric force lines are formed from the seventh electrode 151 to the ninth electrode 153.

12 is a plan view showing a printhead according to a fifth embodiment of the present invention, FIG. 13 is a sectional view showing a vertical structure seen along the line GG shown in FIG. 12, and FIG. 14 is an ink shown in FIG. It is sectional drawing which shows the modification of a discharge part. Here, the same reference numerals as those in Figs. 3 and 4 denote the same members having the same function.

12, 13, and 14, the heater 170 has an approximately "? &Quot; shape, and electrodes 154 are connected to both ends 170a and 170b thereof. The heater 170 is formed in two stages (stepped) as shown in FIG. In addition, as shown in FIG. 13, the heater 171 is formed to be inclined from the outer circumference to the inner circumference, that is, the nozzle 160. This is to make the currents flowing through the respective portions of the heaters 170 and 171 similar to the same voltage by equalizing the resistance values in the respective portions of the heaters 170 and 171. That is, since V = I * R and R = (ρ * l) / A, the length L of the heaters 170 and 171 is changed so that the resistance R is changed. Make the resistance the same. Therefore, the resistance R is the same for the same voltage (V) so that the amount of current in each portion flowing through the heater (170) (171) is similar.

15 is a plan view showing an ink ejecting unit according to a sixth embodiment of the present invention. Here, the same reference numerals as those in Figs. 3 and 4 denote the same members having the same function.

Referring to FIG. 15, the heater 172 has an approximately "Ω" shape and includes a first heater 173 and a second heater 174. The first heater 173 has a larger diameter than the second heater 174 and is installed to surround the second heater 174. In this case, a predetermined space is formed between the first heater 173 and the second heater 174, and the first heater 173 and the second heater 174 are spaced apart from each other. Electrodes 155 are formed and connected to both ends of the heater 172. As described above, configuring the heater 172 as the first heater 173 and the second heater 174, as in the fifth embodiment, indicates the respective resistance values at the first heater 173 and the second heater 174. By differently, to make the amount of current flowing through the first heater 173 and the second heater 174 similar to a predetermined voltage.

16 is a plan view showing an ink ejecting unit according to the seventh embodiment of the present invention. Here, the same reference numerals as those in Figs. 3 and 4 denote the same members having the same function.

Referring to FIG. 16, the heater 175 has a rectangular shape, and electrodes 156 are connected to both ends of the heater 175. The rectangular shape of the heater 175 is to cause the electric force lines generated by the electrode 156 to be uniformly generated when the size of the nozzle 160b is smaller than that of the heater 175. That is, the nozzle 160b does not interfere with the flow of the electric force lines generated by the electrode 156 so that a uniform flow of electric force lines is generated.

The ink ejection process in the ink ejection unit according to the embodiment of the present invention configured as described above will be described in detail.

17 and 18 are cross-sectional views illustrating an ink ejection process of the ink ejection unit illustrated in FIG. 4.

Referring to FIG. 17, a pulsed current is applied to the annular heater 120 while the ink 200 supplied through the manifold 102 and the ink channel 107 is filled in the ink chamber 104 by capillary action. When applied, heat generated by the heater 120 is transferred to the ink 200 through the nozzle plate 110 positioned on the bottom surface thereof. At this time, the ink 200 located on the lower surface of the heater 120 is boiled to generate bubbles 210. The bubble 210 has a donut shape.

Referring to FIG. 18, the bubble 210 expands further over time, merges under the nozzle 110, and expands into an approximately disc shaped bubble 210a having a concave central portion. At the same time, ink in the ink chamber 104 is discharged out of the nozzle 160 by the expanded bubble 200a.

When the application of the current is blocked, the heater 120 is cooled, and the bubble 210a shrinks or bursts. Therefore, ink is filled again in the ink chamber 104.

19 and 20 are cross-sectional views illustrating an ink ejection process in the ink ejection unit illustrated in FIG. 5. Only differences from the ink ejection process shown in FIGS. 17 and 18 are as follows.

When the bubble 210b expands, the bubble 210b expands downward by the bubble guide 108 around the nozzle 160a so that it is difficult to merge under the nozzle 160a. However, by adjusting the length extending downward of the bubble guide 108, it is possible to control the probability that the bubble 210a merges under the nozzle 160a. On the other hand, the discharged droplet 200a is guided in the discharge direction by the droplet guide 190 extending downward from the edge of the nozzle 160a and is discharged in the direction perpendicular to the substrate 100.

Hereinafter, a method of manufacturing the ink jet ink ejecting portion of the present invention will be described.

21 to 26 are cross-sectional views illustrating a process of manufacturing an ink ejecting portion having an ink ejecting portion as illustrated in FIG. 5, and are cross-sectional views taken along line A-A of FIG. 2.

First, the substrate 100 is prepared. In this embodiment, the substrate 100 uses a silicon substrate having a crystal direction of (100) and a thickness of approximately 500 mu m. 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.

Subsequently, when the silicon wafer is placed in an oxidation furnace and wet or dry oxidized, as illustrated in FIG. 23, the surface and the backside of the silicon substrate 100 are oxidized to grow the silicon oxide films 110 and 112. The silicon oxide film 110 formed on the surface side of the substrate 100 becomes a nozzle plate on which a nozzle is formed later.

21 shows only a part of a silicon wafer, and the ink ejecting portion according to the present invention is manufactured in a state of tens to hundreds of chips on one wafer. In addition, in FIG. 21, silicon oxide films 110 and 112 are grown on both the surface and the back surface of the substrate 100, which uses a batch type oxidation furnace in which the back surface of the silicon wafer is exposed to an oxidizing atmosphere. Because However, when using a single wafer type oxidizer which exposes only the surface of the wafer, the silicon oxide film 112 is not formed on the back side. According to the apparatus used in this way, a predetermined material film is formed only on the surface or is formed to the rear surface as shown in FIG. 28 below.

For convenience, hereinafter, another material film (a polycrystalline silicon film, a silicon nitride film, a TEOS oxide film, and the like) described later is illustrated and described as being formed only on the surface side of the substrate 100.

Subsequently, an annular heater 120 is formed on the silicon oxide film 110 on the surface side. The annular heater 120 deposits polycrystalline silicon or tantalum-aluminum alloy doped with impurities on the entire silicon oxide film 110. It is formed by patterning it in an annular shape. Specifically, the doped polycrystalline silicon may be formed to a thickness of about 0.7 to 1 μm by low pressure chemical vapor deposition with a source gas of phosphorus (P), for example, as an impurity. In the case where the heater 120 is formed of a tantalum-aluminum alloy, the tantalum-aluminum alloy film is approximately 0.1 to 0.3 µm by being deposited by sputtering with a target of a tantalum-aluminum alloy or a separate target of tantalum and aluminum. It can be formed in thickness. The deposition thickness of the polycrystalline silicon film or tantalum-aluminum alloy film may be set in another range so as to have an appropriate resistance value in consideration of the width and length of the heater 100. The polycrystalline silicon film or tantalum-aluminum alloy film deposited on the entire surface of the silicon oxide film 110 is patterned by an etching process using a photomask and a photoresist and an etching process using an photomask pattern as an etching mask.

FIG. 22 illustrates a state in which the manifold 102 is formed by etching the substrate 100 from the rear surface of the substrate 100 after depositing the silicon nitride layer 130 on the entire surface of the resultant of FIG. 21. The silicon nitride film 130 may be deposited as a protective film of the annular heater 120, for example, by a low pressure chemical vapor deposition method with a thickness of about 0.5 μm. The manifold 102 is formed by inclining the back surface of the wafer. Specifically, when an etching mask defining an area to be etched is formed on the back surface of the wafer and wet etching is performed for a predetermined time using TMAH (Tetramethyl Ammonium Hydroxide) as an etchant, the etching in the (111) direction becomes slower than other directions. The manifold 102 is formed with an inclination of 54.7 degrees.

Meanwhile, although the manifold 102 is illustrated and described as being formed by obliquely etching the rear surface of the substrate 100, the manifold 102 may be formed by anisotropic etching rather than oblique etching.

FIG. 23 illustrates a state in which the electrode 140 and the nozzle 160 are formed. Specifically, the nozzle (a part of the upper part of the heater 120 of the silicon nitride film 130 of FIG. 22 to be connected to the electrode 140 and a diameter smaller than the diameter of the annular heater 120 inside the annular heater 120). The portions constituting the 160 are etched to expose the heater 120 and the silicon oxide layer 110, respectively. Subsequently, the exposed silicon oxide film 100 is etched to expose the substrate 100 of the portion forming the nozzle 160. The silicon nitride film 130 and the silicon oxide film 110 are etched such that the diameter of the nozzle 160 is approximately 16 to 20 µm.

Subsequently, the electrode 140 is formed by depositing and patterning a metal having good conductivity and easy patterning, such as aluminum or an aluminum alloy, by a sputtering method to a thickness of about 1 μm. In this case, the metal film forming the electrode 140 is simultaneously patterned to form a wiring (not shown) and a bonding pad (20 in FIG. 2) at other portions of the substrate 100. On the other hand, copper may be used as the electrode 140, in which case it is preferable to use electroplating.

Subsequently, as shown in FIG. 24, the TEOS (Tetra ethyle ortho silane) oxide film 150 is deposited and patterned on the entire surface of the substrate 100 on which the nozzle 160 is formed to expose the substrate 100 at the nozzle 160. do. The TEOS oxide film 150 may be deposited by a chemical vapor deposition method at a low temperature, for example, 400 ° C. or less, in which the electrode 140 made of aluminum or an alloy thereof and the bonding pad are not deformed to a thickness of about 1 μm. On the other hand, the nozzle 160 is formed by patterning the silicon nitride film 130 and the silicon oxide film 110 from above, but when the silicon nitride film 130 is patterned from above, the silicon nitride film 130 and the silicon oxide film ( It is also possible to form the TEOS oxide film 150 by leaving the 110 as it is, and then sequentially etching the TEOS oxide film 150, the silicon nitride film 130, and the silicon oxide film 110.

Subsequently, the substrate 100 exposed by the nozzle 160 is etched to form an approximately hemispherical ink chamber. Specifically, as shown in FIG. 24, a photoresist is formed on the entire surface of the substrate 100 on which the nozzle 160 is formed. Is applied and patterned to form photoresist pattern PR that exposes substrate 100 to a diameter smaller than nozzle 160. The photoresist pattern PR is used to finely adjust the diameter of the ink channel 106 to be formed later. The ink channel 106 may be formed by the thickness of the photoresist pattern PR remaining on the sidewall of the nozzle 160. The diameter of is adjusted. On the other hand, when the diameter of the ink channel 106 is made substantially the same as the diameter of the nozzle 160, this photoresist pattern PR is not necessary.

FIG. 25 illustrates a state in which the ink chamber 104 and the ink channel 106 are formed by etching the substrate 100 exposed by the nozzle 160 to a predetermined depth.

First, the ink chamber 104 may be formed by isotropically etching the substrate 100 using the photoresist pattern PR as an etching mask. Specifically, the substrate 100 is dry etched for a predetermined time using XeF 2 gas as an etching gas. Then, as shown, an approximately hemispherical ink chamber 104 having a depth and radius of approximately 20 mu m is formed.

On the other hand, the ink chamber 104 may be formed by etching in two steps, anisotropically etching the substrate 100 and subsequently isotropically etching the photoresist pattern PR as an etching mask. In other words, the silicon substrate 100 is anisotropically etched using inductively coupled plasma etching or reactive ion etching using the photoresist pattern PR as an etch mask. After forming), isotropic etching is then performed in the same manner as described above.

Alternatively, the ink chamber 104 may be formed by changing the portion of the substrate 100 of the substrate 100 to the porous silicon layer and then selectively etching the porous silicon layer to remove the ink chamber 104. . Specifically, a mask that exposes only the central portion of the portion where the ink chamber 104 is to be formed on the surface of the silicon substrate 100 where nothing is formed (i.e., before the step 21) is formed of, for example, a silicon nitride film, and the substrate ( An electrode material such as a gold film is formed on the back surface of 100) and then immersed in an hydrofluoric acid solution and anodized to form a porous silicon layer in a substantially hemispherical shape around the exposed portion of the mask. After the above-described steps of FIGS. 21 to 24 with respect to the silicon substrate 100 in this state, only the porous silicon layer is selectively etched and removed to form a hemispherical ink chamber 104 as shown in FIG. 25. As an etchant that selectively etches and removes only the porous silicon layer, a strong alkali solution such as a KOH solution may be used. On the other hand, the anodizing process may be performed before the step shown in FIG. 23 as above, but when the nozzle 160 is used as a mask in the anodizing process, it may be performed following the step shown in FIG. have.

Subsequently, when the substrate 100 is anisotropically etched using the photoresist pattern PR as an etching mask, the ink channel 106 connecting the ink chamber 104 and the manifold 102 to the bottom of the ink chamber 104 is formed. Is formed. This anisotropic etching may be performed by the above-described inductively coupled plasma etching or reactive ion etching.

FIG. 26 illustrates a state in which the ink ejection part according to the present exemplary embodiment is completed by ashing and stripping and removing the photoresist pattern PR in the state shown in FIG. 25. When the photoresist pattern PR is removed, a hemispherical ink chamber 104 is formed on the surface side of the substrate 100, a manifold 102 is formed on the back side, and the ink chamber 104 and the manifold are formed. An ink channel 106 connecting the 102 is formed, and an ink ejecting portion having a structure in which a nozzle plate having a nozzle 160 having a larger diameter than the ink channel 106 is formed is laminated.

27 and 28 are cross-sectional views illustrating a process of manufacturing an ink ejecting unit having the ink ejecting unit illustrated in FIG. 5, taken along the line AA of FIG. 2.

The manufacturing method of the ink ejecting portion having the ink ejecting portion shown in FIG. 5 is the same until the step of forming the TEOS oxide film 150 of FIG. 24 among the manufacturing methods of the ink ejecting portion having the ink ejecting portion shown in FIG. 27 and further perform the steps shown in FIG.

That is, after forming the TEOS oxide film 150 of FIG. 24 and then, as shown in FIG. 27, the substrate 100 is formed by using the TEOS oxide film 150 and the silicon nitride film 130 having the nozzle 160 as an etch mask. The hole 170 is formed by anisotropic etching a predetermined depth. Subsequently, a predetermined material layer such as a TEOS oxide film is deposited to a thickness of about 1 μm on the entire surface of the substrate 100, and the TEOS oxide film is anisotropically etched until the hole 170 of the silicon substrate 100 is exposed. Spacers 180 are formed on the sidewalls of the spacers 180.

When the exposed silicon substrate 100 is isotropically etched by the above-described method in the state shown in FIG. 27, as illustrated in FIG. 28, a bubble guide (e.g., extending in the ink chamber 104a toward the edge of the nozzle 160a) 108 and an ink ejecting portion having a droplet guide 190 are formed.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various equivalent modifications are possible. For example, the material constituting each element of the ink ejecting portion of the present invention may be made of a material which is not illustrated. That is, the substrate 100 may be replaced with another material having good processability even if it is not necessarily silicon. The same applies to the heater 120, the electrode 140, the silicon oxide film, and the nitride film. In addition, as a method of laminating and forming each material is merely illustrated, various deposition methods and etching methods may be applied.

In addition, the order of each step of the ink ejecting portion manufacturing method of the present invention may be different from that illustrated. For example, etching of the back surface of the substrate 100 for forming the manifold 102 may be performed before the step shown in FIG. 24 or after the step shown in FIG. 25, that is, forming the nozzle 160.

In addition, the specific numerical values illustrated at each step may be adjusted outside the illustrated ranges as much as possible within the range in which the manufactured ink ejecting portion can operate normally.

As described above, the bubblejet inkjet printhead according to the present invention is

First, the ink chamber is hemispherical or curved to facilitate ink ejection and has a fast response speed. In addition, when the nozzle unit is integrated with the heater unit to integrate a circuit, all of the print heads may be realized by one substrate.

Second, by forming the ink channel perpendicular to the substrate, the nozzle arrangement having a high degree of integration is possible, and the refilling and discharging frequency of the ink can be controlled by adjusting the size of the ink channel.

Third, by varying the shape of the electrode connected to the heater in various ways it is possible to apply a current of a uniform distribution to the heater has the effect that the heater generates a uniform heat.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary and will be understood by those of ordinary skill in the art that various modifications and variations can be made therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (23)

Its surface is filled with ink to be discharged. The ink chamber is substantially hemispherical in shape, and a manifold for supplying ink at the bottom thereof, and an ink channel connecting the ink chamber and the manifold at the bottom of the ink chamber. A substrate formed integrally with the substrate; A nozzle plate stacked on the substrate and having a nozzle formed at a position corresponding to a central portion of the ink chamber; A heater positioned on the nozzle plate and surrounding the nozzle, the heater being formed in two stages so as to generate heat evenly by varying the resistance value of each stage; And an electrode electrically connected to both ends of the heater to apply an electric current to the heater. The method of claim 1, Bubble diameter inkjet printhead, characterized in that the diameter of the ink channel is less than or equal to the diameter of the nozzle. The method of claim 1, And a bubble guide and a droplet guide extending from the edge of the nozzle toward the bottom of the ink chamber. delete delete delete delete delete The method of claim 1, The heater is formed to be inclined from the outside inward, the electrode is a bubble jet inkjet printhead, characterized in that connected to both ends of the heater, respectively. delete Its surface is filled with ink to be discharged. The ink chamber, which is substantially hemispherical in shape, has a manifold for supplying ink at the bottom thereof, and an ink channel connecting the ink chamber and the manifold at the bottom of the ink chamber. A substrate formed of; A nozzle plate stacked on the substrate and having a nozzle formed at a position corresponding to a central portion of the ink chamber; A heater positioned on the nozzle plate and formed in a quadrangular shape so as to surround the nozzle to generate a uniform electric force line; And an electrode electrically connected to the heater to apply a current to the heater. delete delete delete delete delete delete delete delete delete delete The method of claim 11, Bubble diameter inkjet printhead, characterized in that the diameter of the ink channel is less than or equal to the diameter of the nozzle. The method of claim 11, Bubble-jet inkjet printhead, characterized in that the bubble and droplet guide extending from the edge of the nozzle in the bottom direction of the ink chamber is formed.