KR100400229B1 - Bubble-jet type inkjet printhead and manufacturing method threrof - Google Patents

Abstract

A bubble jet inkjet print head and a method of manufacturing the same are disclosed. According to the disclosed inkjet print head, an ink chamber is formed on the surface side of the substrate, a manifold is formed below the ink chamber on the rear side of the substrate, and a vertically penetrated ink channel is formed between the ink chamber and the manifold. Is formed. The manifold and ink channel are formed by etching the substrate on its back side. The nozzle plate is integrally formed on the board | substrate, and a nozzle is formed in the nozzle plate in the position corresponding to the center part of the ink chamber. On the nozzle plate, a heater formed in an annular shape surrounding the nozzle and an electrode for applying a current to the heater are formed. Here, the ink chamber has a substantially hemispherical shape, and the ink channel is formed near the edge of the ink chamber. According to the present invention, the reverse flow of the ink is prevented to improve the discharge performance of the ink, it is possible to implement a high-density inkjet print head formed integrally on the silicon wafer substrate.

Description

Bubble-jet type inkjet printhead and its manufacturing method {Bubble-jet type inkjet printhead and manufacturing method threrof}

The present invention relates to an inkjet printhead, and more particularly, to a bubblejet inkjet printhead having a nozzle plate integrally formed on a substrate and having an ink channel perpendicular to an edge of a hemispherical ink chamber, and a method of manufacturing the same. .

In general, an inkjet print head is an apparatus for printing a predetermined color image by ejecting a small droplet of printing ink to a desired position on a recording sheet. The ink ejection method of the inkjet printer includes an electro-thermal transducer (bubble jet method) in which a bubble is generated in the ink by using a heat source to eject the ink with this force, 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 above-described bubble jet ink ejection mechanism is described in more detail as follows. When power is applied to the heater made of the resistive heating element, the ink adjacent to the heater is instantaneously heated to approximately 300 ° C. At this time, bubbles are generated inside the ink, and the generated bubbles grow and apply pressure to the ink chamber filled with ink due to the volume expansion thereof. As a result, the ink near the nozzle is discharged out of the ink chamber through the nozzle.

Such bubble jet inkjet printheads generally have to meet the following requirements. First, the production should be as simple as possible, inexpensive to manufacture, and capable of mass production. Second, 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. Third, 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, the requirements of such inkjet printheads are intimately related to the structure of the ink chamber, the ink flow path and the heater, and thus the form and expansion of bubbles, or the relative size of each element, and often conflict with each other. Therefore, the inkjet printhead of the structure proposed through the conventional patent or literature is not entirely satisfactory, although some of the above requirements are satisfied.

1A and 1B are cutaway perspective views showing the structure of an inkjet printhead disclosed in US Pat. No. 4,882,595 as an example of a conventional bubblejet inkjet printhead, and a cross sectional view for explaining the ink droplet ejection process thereof.

Referring to FIGS. 1A and 1B, a conventional bubble jet inkjet printhead includes a substrate 10 and a partition wall formed on the substrate 10 to form an ink chamber 26 filled with ink 49. The member 38, the heater 12 provided in the ink chamber 26, and the nozzle plate 18 in which the nozzle 16 which discharges the ink droplet 49 'are formed are included. The ink chamber 26 is filled with ink 49 through an ink channel 24 from an ink supply manifold 14 connected to an ink reservoir (not shown), and the nozzle 16 is in communication with the ink chamber 24. The ink 49 is also filled in by capillary action. The print head is provided with a plurality of nozzles 16, correspondingly with a plurality of heaters 12, an ink chamber 26, and the like. These are arranged one row adjacent to each ink supply manifold 14 or one row each on both sides of the manifold 14.

In such a configuration, when a current is supplied to the heater 12, bubbles 48 are formed in the ink 49 filled in the chamber 26 while the heater 12 is heated. Thereafter, the bubble 48 continues to expand, thereby applying pressure to the ink 49 filled in the chamber 26 to push the ink droplet 49 'out through the nozzle 24. Then, the ink 49 is filled again into the chamber 26 while the ink 49 is sucked through the ink channel 24.

However, in order to manufacture a conventional print head having such a structure, a nozzle plate 18 having a nozzle 16 and an ink chamber 26, an ink channel 24, etc. are separately manufactured and manufactured thereon. Since the bonding process is complicated, a manufacturing process is complicated and a problem of misalignment may occur during bonding of the nozzle plate 18 and the substrate 10. In addition, since the ink chamber 26, the ink channel 24, and the manifold 14 are arranged on a plane, there is a limit to increasing the number of nozzles 16 per unit area, that is, the nozzle density, and thus high printing. It is difficult to realize high density inkjet print heads with speed and high resolution.

2 is a schematic cross-sectional view showing the structure of an ink jet print head disclosed in US Pat. No. 6,019,457 as another example of a conventional bubble jet ink jet print head.

2, the nozzle 56 is provided in the upper end of the ink chamber 53 which penetrates the board | substrate 50 up and down, and the ink channel 55 is provided in the opposite lower end part. In addition, heaters 54 arranged in various forms around the nozzles 56 are provided to heat the ink 59 filled in the ink chamber 53 to generate bubbles 58. The bubble 58 continuously expands, and thus pressure is applied to the ink 59 filled in the chamber 53 to push the ink droplet 59 'out through the nozzle 56. Then, the ink 59 is filled in the ink chamber 53 again while the ink 59 is sucked from the manifold 57 through the ink channel 55.

However, the conventional inkjet printhead having the structure as described above has an advantage of increasing the nozzle density since the ink channel 53 and the manifold 57 are disposed below the ink chamber 53, whereas, on the other hand, Since the nozzle 56, the ink chamber 53, and the ink channel 55 are arranged in a straight line, the ink 59 flows backward through the ink channel 55 by the bubble 58 expanding downward. It has the disadvantage of being easy to do.

The present invention has been made to solve the above problems of the prior art, in particular, a nozzle plate with a nozzle is integrally formed on a substrate on which a hemispherical ink chamber is formed, and a vertical ink channel is provided to prevent backflow of ink. It is an object of the present invention to provide a bubble jet inkjet printhead formed near the edge of the ink chamber and a method of manufacturing the same.

1A and 1B are cutaway perspective views and cross-sectional views illustrating an ink droplet ejection process showing an example of a conventional bubble jet inkjet print head.

2 is a schematic cross-sectional view showing another example of a conventional bubble jet inkjet print head.

3 is a schematic plan view of a bubble jet inkjet printhead according to a preferred embodiment of the present invention.

4 is a vertical sectional view of the inkjet printhead of the present invention along the line A-A shown in FIG.

FIG. 5A is a plan view illustrating an example of a shape and a layout of a heater, an electrode, and an ink channel in the ink ejecting part illustrated in FIG. 4.

FIG. 5B is a plan view illustrating another example of the shape and arrangement of the heater, the electrode, and the ink channel in the ink ejecting portion illustrated in FIG. 4.

FIG. 5C is a plan view illustrating still another example of the shape and arrangement of the heater, the electrode, and the ink channel in the ink ejecting portion illustrated in FIG. 4.

6A and 6B are cross-sectional views illustrating a mechanism in which ink is ejected from an inkjet print head according to the present invention.

7 to 19 are cross-sectional views for explaining a preferred manufacturing method of an inkjet print head according to the present invention.

20 to 22 are cross-sectional views illustrating another method of manufacturing an inkjet print head according to the present invention.

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

100,100 ', 100 "... ink discharge part 110,110a, 110b ... substrate

112 Manifold 114 Ink chamber

116,116 '... ink channel 120 ... nozzle plate

122 Nozzle 130,130 '... heater

140 First protective film 150,150 '... electrode

160 ... 2nd Shield 170 ... Nozzle Guide

In order to achieve the above technical problem, the present invention provides an ink chamber filled with ink to be discharged on a surface thereof, and a manifold for supplying ink to the ink chamber is provided below the ink chamber. A substrate formed so as to be positioned, and having an ink channel vertically penetrated between the ink chamber and the manifold; A nozzle plate integrally formed on the substrate and having a nozzle configured to discharge ink at a position corresponding to the center of the ink chamber; A heater formed on the nozzle plate in a shape surrounding the nozzle; And an electrode provided on the nozzle plate and electrically connected to the heater to apply a current to the heater, wherein the ink chamber has a substantially hemispherical shape, and the ink channel is aligned with the nozzle. It provides a bubble jet inkjet printhead, characterized in that not located in the.

Here, the ink channel is preferably formed near the edge of the ink chamber.

In the case where the heater is ring-shaped, the ink channel is preferably located below a portion connected to the electrode of the heater. When the heater is an omega shape, the ink channel is a neck portion of the heater. It is preferable to be located below.

In addition, the cross-sectional shape of the ink channel is preferably circular or rectangular.

Preferably, the substrate is a silicon wafer, and the nozzle plate is a silicon oxide film formed by oxidizing a surface of the silicon wafer.

And, it is preferable that a nozzle guide extending from the edge of the nozzle in the depth direction of the ink chamber is formed.

The substrate may be formed by bonding the ink chamber, the first substrate on which the ink channel is formed, and the second substrate on which the manifold is formed.

According to the printhead of the present invention, it is possible to satisfy all the requirements of the inkjet printhead, and in particular, since the ink channel is formed perpendicular to the edge of the ink chamber, the backflow of the ink is prevented to improve the ejection performance of the ink and to achieve high density. It is possible to implement the inkjet print head.

In addition, the present invention provides a method of manufacturing a print head of the above-described structure.

The manufacturing method of the present invention comprises the steps of: forming a nozzle plate on the surface of the substrate; Forming an annular heater on the nozzle plate; Forming an electrode electrically connected to the heater on the nozzle plate; Forming a nozzle through which the ink is ejected by etching the nozzle plate to a diameter smaller than the diameter of the heater inside the heater; Etching the substrate exposed by the nozzle to form an ink chamber having a substantially hemispherical shape; And forming a manifold for supplying ink by etching the rear surface of the substrate, and forming a vertical ink channel penetrated from the manifold to the vicinity of the edge of the ink chamber.

Here, the substrate is a silicon wafer, and the step of forming the nozzle plate preferably forms a silicon oxide film having a predetermined thickness by oxidizing the surface of the silicon wafer.

In the forming of the ink chamber, it is preferable to form the ink chamber by isotropic dry etching the substrate exposed by the nozzle.

Forming the ink chamber; Anisotropically etching the substrate exposed by the nozzle to form a hole having a predetermined depth; depositing a predetermined material film to a predetermined thickness on the entire surface of the anisotropically etched substrate; and anisotropically etching the material film to form a hole of the hole. The method may include forming a nozzle guide including the material film on the sidewalls of the holes and exposing the bottom and isotropically etching the substrate exposed to the bottom of the holes to form the ink chamber.

Forming an ink channel with the manifold; Forming an etch mask for the manifold on the back of the substrate, and forming an etch mask for the ink channel thereon, and etching the back of the substrate exposed by the etch mask for the ink channel to etch an ink channel having a predetermined depth Forming a forming hole, removing the ink channel etching mask to expose the manifold etching mask, and etching the back surface of the substrate exposed by the manifold etching mask to etch the manifold. And forming the ink channel simultaneously.

In this case, the etch mask for the manifold may be formed by patterning a silicon oxide film formed on the rear surface of the substrate, and the etching mask for the ink channel may be formed by applying a photoresist by spin coating and then patterning the same. .

On the other hand, forming the ink channel with the manifold; Forming an manifold etching mask on the back surface of the substrate, etching the back surface of the substrate exposed by the manifold etching mask to form the manifold, and Forming an etch mask for an ink channel on the back surface, etching the back surface of the substrate exposed by the etch mask for the ink channel to form the ink channel, and removing the etch mask for the ink channel It can be made, including.

In this case, the etch mask for the manifold is made by patterning a silicon oxide film formed on the back of the substrate, the etching mask for the ink channel may be made by applying a photoresist by spray coating method and then patterning it.

In the above two cases, the etching of the back surface of the substrate is preferably performed by a dry etching method.

In addition, the present invention provides a method for manufacturing a print head of the above structure using two substrates.

Another method of manufacturing a print head of the present invention comprises the steps of: forming a nozzle plate on a surface of a first substrate; Forming an annular heater on the nozzle plate; Forming an electrode electrically connected to the heater on the nozzle plate; Forming a nozzle through which the ink is ejected by etching the nozzle plate to a diameter smaller than the diameter of the heater inside the heater; Etching the first substrate exposed by the nozzle to form an ink chamber having a substantially hemispherical shape; Etching a rear surface of the first substrate to form a vertical ink channel penetrating to an edge of the ink chamber; Forming a manifold for supplying ink to the second substrate; And bonding the first substrate on the second substrate.

Here, the first substrate and the second substrate are both silicon wafers, and the forming of the nozzle plate preferably forms a silicon oxide film having a predetermined thickness by oxidizing the surface of the silicon wafer for the first substrate.

The ink channel may be formed by forming an etching mask for an ink channel on a rear surface of the first substrate and dry etching the rear surface of the first substrate exposed by the etching mask for the ink channel.

The manifold may be formed by removing a portion of the second substrate by etching or by sand blast.

According to the above-described manufacturing method of the present invention, since the nozzle plate on which the nozzle is formed is integrally formed on the substrate on which the ink chamber is formed, the problem of misalignment between the nozzle and the ink chamber is solved, and it is compatible with the manufacturing process of a general semiconductor device, thereby allowing a large amount of Production becomes easy. On the other hand, in the case of the manufacturing method using two substrates, the first substrate and the nozzle plate on which the ink chamber is formed have the advantages as described above.

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 a schematic plan view of a bubble jet inkjet printhead according to a preferred embodiment of the present invention.

Referring to FIG. 3, in the bubble jet inkjet printhead according to the present invention, the ink ejection portions 100 are arranged in two rows on the ink supply manifold 112 indicated by a dotted line, and each ink ejection portion 100 is connected to each other. Bonding pads 102 to be electrically connected and to which wires are to be bonded are disposed at both sides of the ink ejection part 100. Manifold 112 is also connected to an ink reservoir (not shown) containing ink. Meanwhile, one manifold 112 may be formed for each column of the ink ejection unit 100. Although the ink ejection parts 100 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. Meanwhile, although a print head using only one color of ink is illustrated in the drawing, three or four groups of ink ejection units may be disposed for each color for color printing.

4 is a vertical sectional view of the inkjet printhead of the present invention along the line A-A shown in FIG.

As shown in the drawing, an ink chamber 114 in which ink is filled is formed on the surface side of the substrate 110 of the ink ejecting unit, and a manifold 112 is formed on the back side thereof to supply ink to the ink chamber 114. do. Here, it is preferable that the board | substrate 110 consists of silicon widely used for manufacture of an integrated circuit, and it is preferable that the ink chamber 114 has a substantially hemispherical shape.

An ink channel 116 is formed between the ink chamber 114 and the manifold 112 to connect them to each other. The ink channel 114 is formed perpendicular to the edge of the ink chamber 114, and its cross-sectional shape is preferably circular. On the other hand, the position of the ink channel 116 and its cross-sectional shape can be changed. That is, although the position of the ink channel 116 is not exactly formed at the edge of the ink chamber 114, the position outside the center of the ink chamber 114, for example, the ink chamber (not to be in line with the nozzle 122 described later) 114) may be formed near the edges. In addition, the cross-sectional shape of the ink channel 116 may have various shapes such as an ellipse or a polygon, even if it is not circular.

On the surface of the substrate 110, a nozzle plate 120 provided with a nozzle 122 is stacked at a position corresponding to the center of the ink chamber 114, and the nozzle plate 120 forms an upper wall of the ink chamber 114. Is achieved. When the substrate 110 is made of silicon, the nozzle plate 120 may be formed of a silicon oxide film formed by oxidizing the silicon substrate 110.

As described above, in the print head of the present invention, the nozzle 122 is positioned at the center of the ink chamber 114, but the ink channel 114 is disposed near the edge thereof beyond the center of the ink chamber 114. Thus, the nozzle 122 and the ink chamber 114 and the ink channel 116 are not arranged in a straight line. This arrangement of the ink channel 116 is effective to prevent the problem of ink flowing back through the ink channel 116 by the expansion of the bubble, which will be described in detail later. In addition, since the ink channel 116 and the manifold 112 are disposed below the ink chamber 114, the area occupied by the unit nozzle 122 is narrowed to increase the nozzle density.

The heater 130 for bubble generation is formed on the nozzle plate 120 in a shape surrounding the nozzle 122. The heater 130 preferably has a circular ring shape and is made of a resistive heating element such as polysilicon or a tantalum-aluminum alloy doped with impurities. The outer diameter of the heater 130 is preferably smaller than the diameter of the ink chamber 114.

A first passivation layer 140 is formed on the nozzle plate 120 and the heater 130 to protect the heater 130. As the first passivation layer 140, a silicon nitride layer may be preferably used.

In addition, an electrode 150 made of a metal is usually connected to the heater 130 to apply a pulsed current. FIG. 5A is a plan view illustrating an example of a shape and arrangement of a heater, an electrode, and an ink channel in the ink ejecting part illustrated in FIG. 4. Referring to this, the electrodes 150 are connected to each other in a ring-shaped heater 130. It is. That is, the heater 130 is connected in parallel between the electrodes 150. In the ink discharge part 100 having the ring-shaped heater 130, the ink channel 116 is positioned below a portion that is connected to the electrode 150 of the heater 130.

Meanwhile, FIG. 5B is a plan view illustrating another example of the shape and arrangement of the heater, the electrode, and the ink channel in the ink ejecting part illustrated in FIG. 4. Referring to this, the heater 130 ′ may roughly surround the nozzle 122. It is formed in an omega shape, and the electrodes 150 'are connected to both ends of the heater 130', respectively. That is, the heater 130 'shown in FIG. 5B is connected in series between the electrodes 150'. Then, in the ink ejection part 100 'having the heaters OMEGA 130', the ink channel 116 is located below the neck of the heater 130 '. This is because it is possible to minimize the non-uniformity of the fluid pressure in the ink chamber 114 during the growth and ejection of bubbles.

5A and 5B, the cross-sectional shape of the ink channel 116 is shown as a circle, but may be rectangular or elliptical to improve ink refill and discharge frequency. For example, as shown in FIG. 5C, which shows another example of the shape and arrangement of the heater, electrode, and ink channel, the ink channel 116 ′ may have a rectangular cross-sectional shape, and also out of the ink chamber 114. It may be a bit off.

Referring back to FIG. 4, a second passivation layer 160 is formed on the electrode 150 to protect it. As the second passivation layer 160, a silicon oxide layer or a tetraethyletho ortho silicate (TEOS) oxide layer may be formed.

In addition, a nozzle guide 170 extending from the edge of the nozzle 122 in the depth direction of the ink chamber 114 may be formed on the ink chamber 114. The nozzle guide 170 serves to guide the ejected ink droplets so that the ink droplets can be ejected in a direction that is exactly perpendicular to the substrate 110.

Hereinafter, the ink droplet ejection mechanism of the bubble jet inkjet printhead according to the present invention will be described with reference to FIGS. 6A and 6B.

Referring first to FIG. 6A, ink 190 is supplied into the ink chamber 114 through the manifold 112 and the ink channel 116 by capillary action. In a state where the ink 190 is filled in the ink chamber 114, when a pulsed current is applied to the heater 130 through the electrode 150, heat is generated in the heater 130. The generated heat is transferred to the ink 190 inside the ink chamber 114 through the nozzle plate 120 under the heater 130, whereby the ink 190 boils to generate bubbles 195. The shape of the bubble 195 becomes a substantially donut shape according to the shape of the heater 130.

The donut shaped bubble 195 expands over time, and as shown in FIG. 6B, ink droplets (i.e., through the nozzle 122 from the ink chamber 114 by the pressure of the expanded bubble 196) are shown. 191 is discharged.

At this time, since the expanded bubble 196 blocks the ink channel 116 located at the edge of the ink chamber 114, the back flow of the ink 190 is prevented. Therefore, cross talk with other ink ejecting portions adjacent to each other is suppressed, thereby improving ink ejection characteristics.

In addition, the discharged droplet 191 is guided in the discharge direction by the nozzle guide 170 so that the discharged droplet 191 may be discharged in a direction perpendicular to the substrate 110.

In addition, since the shape of the ink chamber 114 is hemispherical, the expansion paths of the bubbles 195 and 196 are more stable than the conventional rectangular parallelepiped or pyramid ink chambers.

Next, a method of manufacturing a bubblejet inkjet printhead according to the present invention will be described.

7 to 19 are cross-sectional views for explaining a preferred manufacturing method of an inkjet print head according to the present invention.

First, referring to FIG. 7, in this embodiment, the substrate 110 uses a silicon substrate having a thickness of approximately 300 μm. 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. When the silicon substrate 110 is placed in an oxidation furnace and wet or dry oxidized, the front and back surfaces of the silicon substrate 110 are oxidized to form silicon oxide films 120 and 122. The silicon oxide film 120 on the surface side of the substrate 110 is the nozzle plate described above, and the silicon oxide film 122 on the back side is the first etching mask 122 for forming the manifold 112 as shown in FIG. 17. Can be used as').

On the other hand, shown in Figure 7 shows a very small portion of the silicon wafer, the print head according to the present invention is manufactured in the state of tens to hundreds of chips on one wafer. In addition, in FIG. 7, the silicon oxide films 120 and 122 are formed on both the surface and the back surface of the substrate 110 because the back surface of the silicon wafer is also used in a batch oxidation furnace in which the oxide atmosphere is exposed. However, in the case of using a single-layer oxide furnace in which only the surface of the wafer is exposed, the silicon oxide film 122 is not formed on the back side.

Subsequently, a heater 130 is formed on the silicon oxide film 120 toward the surface of the substrate 110. The heater 130 is formed by depositing polysilicon doped with impurities on the entire surface of the silicon oxide film 120 and then patterning it in an annular shape. Specifically, the doped polysilicon may be formed to a thickness of approximately 0.7 to 1 μm by low pressure chemical vapor deposition (LPCVD) by depositing with a source gas of phosphorus (P), for example, as an impurity. The deposition thickness of this polysilicon 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 130. The polysilicon film deposited on the entire surface of the silicon oxide film 120 is patterned by a photolithography process using a photomask and a photoresist and an etching process by etching the photoresist pattern as an etch mask.

FIG. 8 illustrates a state in which the electrode 150 is formed on the first passivation layer 140 to protect the heater 130 on the entire surface of the resultant of FIG. 7. Specifically, the first passivation layer 140 may be formed by, for example, depositing a silicon nitride layer by a chemical vapor deposition method to a thickness of about 0.5 μm. The first passivation layer 140 is partially etched to expose the heater 130 of the portion to be connected to the electrode 150. Subsequently, the electrode 150 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. At this time, the metal film constituting the electrode 150 is patterned at the same time to form a wiring (not shown) and a bonding pad (102 in FIG. 3) at other portions of the substrate 110.

9 illustrates a state in which a second passivation layer 160 for protecting the electrode 150 and a nozzle 122 through which ink is discharged are formed on the entire surface of the substrate 110 on which the electrode 150 is formed. Specifically, the second passivation layer 160 may be formed by depositing the TEOS oxide layer by a plasma chemical vapor deposition method with a thickness of about 0.7 to 1 μm. Subsequently, the second passivation layer 160, the first passivation layer 140, and the silicon oxide layer 120 are sequentially etched into a diameter smaller than the diameter of the heater 130, for example, about 16 to 20 μm, into the heater 130. The nozzle 122 is formed. The nozzle 122 may be formed by a photo process using a photomask and a photoresist and an etching process by etching the photoresist pattern as an etching mask.

10 and 11 are diagrams for describing a step of forming the nozzle guide 170. On the other hand, when the nozzle guide 170 is not formed, the steps shown in FIGS. 10 and 11 are not performed.

First, as shown in FIG. 10, the substrate 110 exposed by the nozzle 122 is anisotropically etched to form holes 172 having a predetermined depth. Subsequently, a predetermined material film, such as TEOS oxide film 174, is deposited on the entire surface of the ink ejection portion to a thickness of about 1 탆. Next, when the TEOS oxide film 174 is anisotropically etched until the substrate 110 is exposed, the nozzle guide 170 is formed on the sidewall of the hole 172 as shown in FIG. 11.

12 shows a state in which the ink chamber 114 and the ink channel 116 are formed. Specifically, the ink chamber 114 is formed by isotropic etching of the substrate 110 exposed by the nozzle 122. Can be. Specifically, the substrate 110 is dry-etched for a predetermined time using XeF ₂ gas or BrF ₃ gas as an etching gas. Then, as shown, an approximately hemispherical ink chamber 114 having a depth and radius of approximately 30 mu m is formed.

13 to 17 illustrate the steps of forming the manifold 112 and the ink channel 116 by etching the back surface of the substrate 110.

First, as shown in FIG. 13, a first etching mask 122 ′ is formed on the rear surface of the substrate 110. The first etching mask 122 ′ is for forming the manifold 112 in the step of FIG. 17. The first etching mask 122 ′ may be formed by patterning the silicon oxide film 122 deposited on the back surface of the substrate 110 in the step of FIG. 7. . Meanwhile, the first etching mask 122 ′ may be formed by depositing a material layer separate from the silicon oxide layer 122 on the back surface of the substrate 110 and then patterning the material layer.

Next, as shown in FIG. 14, the second etching mask 124 is formed on the rear surface of the substrate 110 on which the first etching mask 122 'is formed. The second etching mask 124 is for forming the channel forming hole 116 ′ in the step of FIG. 15. The second etching mask 124 may be formed by applying a photoresist to the back surface of the substrate 110 by spin coating and patterning the photoresist. .

Subsequently, as shown in FIG. 15, the rear surface of the substrate 110 exposed by the second etching mask 124 is etched to form a channel forming hole 116 ′ having a predetermined depth. In detail, the channel forming hole 116 ′ may be formed by dry etching the rear surface of the substrate 110 to a depth of about 60 μm using an ICP-RIE (Inductively Coupled Plasma-Reactive Ion Etching) method. After forming the channel forming hole 116 ′, the second etching mask 124 is removed to form a manifold (refer to FIG. 16) of the back surface of the first etching mask 122 ′ and the substrate 110 as shown in FIG. 16. 112 of 17) exposes the site to be formed.

Finally, as shown in FIG. 17, the rear surface of the exposed substrate 110 is etched to form the manifold 112. At the same time, the channel forming hole 116 ′ is deeply etched and connected to the edge of the ink chamber 114 to form the ink channel 116. Such a step of forming the manifold 112 and the ink channel 116 may also be performed by dry etching using the ICP-RIE method.

On the other hand, the manifold 112 and the ink channel 116 may be formed by a method different from the above-described method, which is illustrated in FIGS. 18 and 19.

First, after forming the first etching mask 122 ′ on the back surface of the substrate 110 in FIG. 13, the back surface of the exposed substrate 110 is etched as shown in FIG. 18 to manifold 112. To form. Manifold 112 may be formed by dry etching using the ICP-RIE method as described above.

Subsequently, as illustrated in FIG. 19, a second etching mask 124 ′ is formed on the rear surface of the substrate 110 on which the manifold 112 is formed. The second etching mask 124 ′ may be formed by applying and patterning a photoresist on the back surface of the substrate 110 by spray coating.

Finally, when the substrate 110 exposed by the patterned second etching mask 124 'is dry-etched using the ICP-RIE method and then the second etching mask 124' is removed, the substrate 110 shown in FIG. As the ink channel 116 is formed, the inkjet print head according to the present invention is completed.

On the other hand, the formation of the manifold 112 and the ink channel 116 may be performed by a wet etching method, it is preferable to dry etching by the ICP-RIE method as described above. According to the dry etching method, the position and size of the ink channel 116 can be easily adjusted, thereby making the area of the manifold 112 smaller, thereby making it possible to manufacture a structurally robust print head. This is because contamination of the substrate 110 may be prevented. Since the substrate 110 is not etched from the surface side thereof to form the ink channel 116, the substrate 110 is etched from the rear side thereof to form the ink channel 116, so that the substrate 110 is formed on the surface of the substrate 110. The elements are not damaged by the plasma.

20 to 22 are cross-sectional views illustrating another method of manufacturing an inkjet print head according to the present invention. In this manufacturing method, an ink chamber and an ink channel are formed on a first substrate, and a manifold is formed on a second substrate separate from the first substrate, and then the first substrate and the second substrate are bonded to each other to thereby inkjet print the present invention. The method of manufacturing the head.

First, as shown in FIG. 20, the heater 130, the electrode 150, the nozzle 122, the nozzle guide 170, and the hemispherical ink chamber 114 are sequentially formed on the surface side of the first substrate 110a. . Here, the first substrate 110a uses a silicon substrate whose thickness is approximately 100 μm. Since the components such as the heater 130 formed on the surface of the first substrate 110a are formed by the same method as described above, the description thereof will be omitted. Subsequently, an etching mask is formed on the rear surface of the first substrate 110a to expose a portion where the ink channel 116 is to be formed, and the rear surface of the exposed first substrate 110a is etched to the edge of the ink chamber 114. The ink channel 116 to be connected is formed. The ink channel 116 may be formed by dry etching the back surface of the first substrate 110a using the ICP-RIE method. The etching mask may be removed after the ink channel 114 is formed.

Apart from the process of forming the ink chamber 114, the ink channel 116, and the like on the first substrate 110a, the manifold 112 is formed on the second substrate 110b as shown in FIG. 21. do. Here, the second substrate 110b uses a silicon substrate whose thickness is approximately 600 µm. The manifold 112 may be formed by the dry etching method described above, or may be formed by a wet etching method using Tetramethyl Ammonium Hydroxide (TMAH) as an etchant. Meanwhile, the manifold 112 may be formed by removing a portion where the manifold 112 of the second substrate 110b is to be formed by a sand blast.

Finally, by bonding the first substrate 110a shown in FIG. 20 and the second substrate 110b shown in FIG. 21, two substrates 110a and 110b as shown in FIG. 22 are bonded to each other. An inkjet print head according to the invention is completed. Here, the bonding of the two substrates 110a and 110b may be performed by a well-known silicon direct bonding (SDB) method.

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 modifications and equivalent other embodiments are possible. For example, the materials used to construct each element of the printhead in the present invention may use materials not illustrated. That is, the substrate may be replaced with another material having good processability even if it is not necessarily silicon. The same applies to a heater, an electrode, a silicon oxide film, and a 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 specific values exemplified in each step may be adjusted beyond the exemplified ranges within the range in which the manufactured print head can operate normally. In addition, the order of each step of the printhead manufacturing method of the present invention may be different from that illustrated.

As described above, the bubblejet inkjet printhead and its manufacturing method according to the present invention have the following effects.

First, since the ink channel is located near the edge of the ink chamber, the expanded bubble blocks the ink channel and prevents backflow of the ink. Therefore, interference with other ink ejecting portions adjacent to each other is suppressed and ink ejection characteristics are improved.

Second, since the ink channel and the manifold are disposed below the ink chamber, the nozzle density is increased, so that it is easy to realize a high resolution print head.

Third, since the nozzle plate provided with the nozzle is integrally formed on the substrate on which the ink chamber and the ink channel are formed, the conventional problem of misaligning the ink chamber and the nozzle is solved. Meanwhile, even when two substrates are used, the first substrate and the nozzle plate on which the ink chambers are formed are integrally formed, and thus have the above advantages. In addition, it is compatible with the general manufacturing process of semiconductor devices, and mass production becomes easy.

Fourth, by forming the heater in an annular shape and forming the shape of the ink chamber in a hemispherical shape, the expansion path of the bubble is stable, the back flow of ink is suppressed, and interference with other ink ejecting portions can be avoided. The discharge direction is guided so that the droplets can be discharged in a direction that is exactly perpendicular to the substrate.

Claims (25)

An ink chamber filled with ink to be discharged is formed on a surface thereof, and a manifold for supplying ink to the ink chamber is formed below the ink chamber, and an ink chamber and the manifold A substrate having an ink channel vertically penetrated therebetween; A nozzle plate integrally formed on the substrate and having a nozzle configured to discharge ink at a position corresponding to the center of the ink chamber; A heater formed on the nozzle plate in a shape surrounding the nozzle; And An electrode provided on the nozzle plate and electrically connected to the heater to apply a current to the heater; And the ink chamber has a substantially hemispherical shape, and wherein the ink channel is not located in line with the nozzle. The method of claim 1, And the ink channel is formed near an edge of the ink chamber. The method of claim 1, The heater is a ring-shaped, the ink channel is a bubble jet inkjet printhead, characterized in that located below the portion connected to the electrode of the heater. The method of claim 1, The heater is omega-shaped, the ink channel is a bubble jet inkjet print head, characterized in that located below the neck of the heater. The method of claim 1, The cross-sectional shape of the ink channel is a bubble jet inkjet printhead, characterized in that the circular. The method of claim 1, The cross-sectional shape of the ink channel is a bubble jet inkjet printhead, characterized in that the rectangular. The method of claim 1, The substrate is a silicon wafer, and the nozzle plate is a bubble jet inkjet printhead, characterized in that the silicon oxide film formed by oxidizing the surface of the silicon wafer. The method of claim 1, And a nozzle guide extending from the edge of the nozzle in the depth direction of the ink chamber. The method of claim 1, The substrate is a bubble jet inkjet printhead, characterized in that the ink chamber, the first substrate on which the ink channel is formed, and the second substrate on which the manifold is formed are bonded. Forming a nozzle plate on the surface of the substrate; Forming an annular heater on the nozzle plate; Forming an electrode electrically connected to the heater on the nozzle plate; Forming a nozzle in which ink is ejected by etching the nozzle plate to a diameter smaller than the diameter of the heater inside the heater; Etching the substrate exposed by the nozzle to form an ink chamber having a substantially hemispherical shape; And And forming a manifold for supplying ink by etching the rear surface of the substrate, and forming a vertical ink channel penetrated from the manifold to the vicinity of the edge of the ink chamber. The method of claim 10, The substrate is a silicon wafer, and the forming of the nozzle plate comprises oxidizing the surface of the silicon wafer to form a silicon oxide film having a predetermined thickness. The method of claim 10, A first passivation film is formed on the heater, the electrode is formed on the first passivation film, and the second passivation film is formed on the electrode. The method of claim 10, The forming of the ink chamber may include forming the ink chamber by isotropic dry etching the substrate exposed by the nozzle. The method of claim 10, wherein forming the ink chamber; Anisotropically etching the substrate exposed by the nozzle to form a hole having a predetermined depth; Depositing a predetermined material layer on a surface of the anisotropically etched substrate to a predetermined thickness; Anisotropically etching the material film to expose the bottom of the hole and simultaneously forming a nozzle guide made of the material film on the sidewall of the hole; And isotropically etching the substrate exposed at the bottom of the hole to form the ink chamber. The method of claim 14, The material film is a manufacturing method of an inkjet print head, characterized in that the TEOS oxide film. 11. The method of claim 10, wherein forming the manifold and ink channels; Forming an etch mask for a manifold on the back surface of the substrate, and forming an etching mask for an ink channel thereon; Etching the back surface of the substrate exposed by the etching mask for the ink channel to form an ink channel forming hole having a predetermined depth; Removing the etching mask for the ink channel to expose the etching mask for the manifold; And etching the back surface of the substrate exposed by the etch mask for manifold to form the manifold and the ink channel at the same time. The method of claim 16, The etching mask for the manifold is formed by patterning a silicon oxide film formed on the back surface of the substrate, and the etching mask for the ink channel is formed by applying a photoresist by spin coating and patterning the same. Manufacturing method. 11. The method of claim 10, wherein forming the manifold and ink channels; Forming an etch mask for a manifold on a rear surface of the substrate; Etching the back surface of the substrate exposed by the manifold etching mask to form the manifold; Forming an etching mask for an ink channel on a rear surface of the substrate on which the manifold is formed; Etching the back surface of the substrate exposed by the etching mask for the ink channel to form the ink channel; Removing the etch mask for the ink channel. The method of claim 18, The etching mask for the manifold is formed by patterning a silicon oxide film formed on the back surface of the substrate, and the etching mask for the ink channel is formed by applying a photoresist by spray coating and patterning the same. Manufacturing method. The method of claim 16 or 18, And etching the back surface of the substrate by a dry etching method. Forming a nozzle plate on the surface of the first substrate; Forming an annular heater on the nozzle plate; Forming an electrode electrically connected to the heater on the nozzle plate; Forming a nozzle through which the ink is ejected by etching the nozzle plate to a diameter smaller than the diameter of the heater inside the heater; Etching the first substrate exposed by the nozzle to form an ink chamber having a substantially hemispherical shape; Etching a rear surface of the first substrate to form a vertical ink channel penetrating to an edge of the ink chamber; Forming a manifold for supplying ink to the second substrate; And Bonding the first substrate onto the second substrate. The method of claim 21, The first substrate and the second substrate are both silicon wafers, and the forming of the nozzle plate comprises oxidizing a surface of the silicon wafer for the first substrate to form a silicon oxide film having a predetermined thickness. Manufacturing method. The method of claim 21, The forming of the ink channel may include forming an ink channel etching mask on a rear surface of the first substrate, and dry etching the back surface of the first substrate exposed by the ink channel etching mask to form the ink channel. A method of manufacturing an inkjet print head, characterized in that. The method of claim 21, The forming of the manifold may include forming the manifold by forming an etch mask for the manifold on the second substrate and removing a predetermined portion of the second substrate exposed by the etching mask by etching. A method of manufacturing an inkjet print head, characterized in that. The method of claim 21, The forming of the manifold may include forming the manifold by removing a predetermined portion of the second substrate by sand blasting.