Source: https://patents.google.com/patent/DE60220633T2/en
Timestamp: 2020-01-26 11:43:13
Document Index: 653808475

Matched Legal Cases: ['art 311', 'art 311', 'art 311', 'art 311', 'art 311', 'art 311', 'art 311', 'art 311', 'art 311', 'art 311', 'art 311', 'art 311', 'art 311']

DE60220633T2 - Piezoelectric ink jet printhead and method of making the same - Google Patents
Piezoelectric ink jet printhead and method of making the same
DE60220633T2
DE60220633T2 DE2002620633 DE60220633T DE60220633T2 DE 60220633 T2 DE60220633 T2 DE 60220633T2 DE 2002620633 DE2002620633 DE 2002620633 DE 60220633 T DE60220633 T DE 60220633T DE 60220633 T2 DE60220633 T2 DE 60220633T2
DE2002620633
DE60220633D1 (en
Jae-woo Paldal-gu Suwon-City Chung
Jae-chang Taean-eub Hwaseong-gun Lee
Seung-mo Yongin-city Kyungki-do Lim
2001-12-18 Priority to KR2001080908 priority Critical
2001-12-18 Priority to KR10-2001-0080908A priority patent/KR100438836B1/en
2007-07-26 Publication of DE60220633D1 publication Critical patent/DE60220633D1/en
2008-02-21 Publication of DE60220633T2 publication Critical patent/DE60220633T2/en
The The present invention relates to an ink jet print head, and more particularly a piezoelectric ink jet print head formed on a Silicon substrate and a method for its production using a micromachining technique.
Generally are inkjet printheads Apparatus for printing a particular color image by ejecting a small volume of a printing ink droplet to a desired position a recording sheet. Ink ejection mechanisms in an inkjet printer are roughly categorized into two different types: an electrothermal Transducer type (bubble-jet type), where a heat source is used, to bubble in ink to form, thereby ejecting the Ink is caused, and an electromechanical transducer type, at the ink through a change in the ink volume due to deformation of a piezoelectric Elements ejected becomes.
The typical structure of an ink jet print head using an electromechanical transducer is shown in FIG 1 shown. In reference to 1 are an ink reservoir 2 , a throttle 3 , an ink chamber 4 and a nozzle 5 for forming an ink passage in a passage plate 1 formed and a piezoelectric actuator 6 is on the passage plate 1 educated. The ink reservoir 2 stores ink supplied from an ink tank (not shown) and the throttle 3 is a passage through which ink from the reservoir 2 to the ink chamber 4 is supplied. The ink chamber 4 is filled with ejected ink. The volume of the ink chamber 4 is by operating the piezoelectric actuator 6 changeable, whereby a change in pressure for ink ejection or inflow is generated. The ink chamber 4 is also referred to as a pressure chamber.
The passage forming plate 1 is formed by cutting a plurality of thin plates formed of ceramics, metal or plastic, forming a part of the ink passage, and then stacking the plurality of thin plates. The piezoelectric actuator 6 is above the ink chamber 4 and includes a piezoelectric thin plate stacked on an electrode for applying a voltage to the piezoelectric thin plate. Thus, a part serving as an upper wall of the ink chamber 4 in the passage forming plate 1 forms, as a vibration plate 1a that of the piezoelectric actuator 6 is deformed.
The How a conventional one works piezoelectric ink-jet printhead having the above structure is described below.
When the vibration plate 1a by operating the piezoelectric actuator 6 is deformed, the volume of the ink chamber 4 reduced. As a result, due to a pressure change in the ink chamber 4 , Ink in the ink chamber 4 through the nozzle 5 pushed out. Subsequently, the volume of the ink chamber increases 4 when the vibration plate 1a by operating the piezoelectric actuator 6 is returned to its original state. As a result, due to a pressure change in the ink chamber 4 , in the ink reservoir 2 stored ink through the throttle 3 in the ink chamber 4 guided.
As an example of the piezoelectric ink-jet printhead is shown in FIG 2 a in U.S. Patent No. 5,856,837 disclosed piezoelectric inkjet printhead shown. 3 FIG. 12 is a cross-sectional view of the conventional piezoelectric ink-jet printhead in the longitudinal direction of a pressure chamber of FIG 2 and 4 is a cross-sectional view along the line AA 'of 3 ,
Related to the 2 to 4 For example, the conventional piezoelectric ink-jet printhead is by stacking a plurality of thin plates 11 to 16 and adhering to each other. That is, a first plate 11 on which a nozzle 11a is formed, is ejected through the ink is then placed on the underside of the printhead, a second plate 12 on which an ink reservoir 12a and an ink outlet 12b are formed on the first plate 11 hung up and a third plate 13 on which an ink inlet 13a and an ink outlet 13b are formed on the second plate 12 hung up. An ink supply passage 17 , through the ink to the ink reservoir 12a from an ink tank (not shown) is on the third plate 13 intended. A fourth plate 6 on which an ink inlet 14a and an ink outlet 14b are formed on the third plate 13 hung up and a fifth plate 15 on which a pressure chamber 15a is formed, whose both ends with the ink inlet 14a or the ink outlet 14b is on the fourth plate 6 hung up. The ink inlets 13a and 14a serve as a passage through the ink of the pressure chamber 15a from the ink reservoir 12a is supplied, and the ink outlets 12b . 13b and 14b serve as a passage through the ink from the pressure chamber 15a to the nozzle 11a is ejected. A sixth plate 16 for closing the upper part of the pressure chamber 15a is on the fifth plate 15 hung up, and a drive electrode 20 and a piezoelectric layer 21 are as a piezoelectric actuator on the sixth plate 16 educated. In this way serves the sixth plate 16 as a vibrating plate actuated by the piezoelectric actuator, and the volu men of the pressure chamber 15a under the sixth plate 16 is changed according to the deformation of the vibration plate.
Generally, the first, second and third plates 11 . 12 and 13 formed by etching or printing a thin metal plate and the fourth, fifth and sixth plates 14 . 15 and 16 are formed by cutting a ceramic material in the form of a thin plate. Meanwhile, the second plate 12 on which the ink reservoir 12a is formed by injection molding or compression molding of a thin plastic material or an adhesive in film form, or by screen printing an adhesive in the form of a paste. The on the sixth plate 16 formed piezoelectric layer 21 is formed by coating a ceramic material in the form of a paste having piezoelectric property and sintering the ceramic material.
As described above, for the production of the in 2 As shown in the conventional piezoelectric ink-jet printhead, a plurality of metal plates and ceramic plates are separately processed using various processing methods and then stacked and adhered together using a specific adhesive. In the conventional printhead, however, the number of plates constituting the printhead is quite large, and thereby the number of processes for aligning the plates is increased, thereby increasing alignment errors. When an alignment error occurs, ink is not smoothly supplied through the ink passage, thereby reducing the ink ejection performance of the print head. In particular, when producing high-density print heads to improve printing resolution, it is necessary to improve the precision in the above-mentioned alignment process, thereby increasing the manufacturing cost.
As well For example, the plurality of disks forming the print head are different Materials manufactured using different methods. Therefore, the printhead manufacturing process becomes complicated and it is difficult to glue the different materials together, whereby the production yield decreases. Although in the printhead manufacturing process the majority of plates precise aligned and glued together, may be due to a difference in the thermal expansion coefficient between the different materials through a change the ambient temperature is conditional when the printhead is used will also occur alignment errors or deformations.
EP 968825 describes an ink jet printhead formed of first and second components. Each of the first and second components is formed of multiple layers of individual substrates which together form the components of the printhead. Ink is expelled by a piezoelectric element on top of the upper substrate.
EP 1101615 describes an ink jet printhead having a substrate forming passageways and another defining nozzles and also defining a cavity in which piezoelectric elements are received. Both substrates can be formed of silicon monocrystal.
US 2001/002838 provides a monolithic nozzle array of silicon.
US 5,992,974 provides an ink-jet printhead having a nozzle plate formed by etching a monocrystalline silicon substrate.
US 6,033,581 describes an ink jet printhead formed from an etched layer of silicon on a support.
JP 6-206315 describes a method of manufacturing an ink jet printhead by bonding a plurality of silicon substrates together.
JP 2000-94696 describes a method of forming a gap in an ink jet printhead.
According to one Aspect of the invention is a piezoelectric ink jet printhead according to claim 1 and a method for its preparation according to claim 15 available posed.
The present invention provides a piezoelectric ink jet printhead, wherein elements on three monocrystalline silicon substrates using a micromachining technology are integrated to a precise alignment to achieve, to improve the adhesive properties and the manufacturing process for one To simplify printhead, and a method for its production to disposal.
In accordance with one aspect of the present invention, a piezoelectric ink jet printhead is provided. The piezoelectric ink-jet printhead includes an upper substrate through which an ink supply passage through which ink is supplied is formed, and a pressure chamber filled with ink to be ejected is formed on the lower surface of the upper substrate, an intermediate substrate having an ink reservoir passing through the ink supply is connected and in the and a damper is formed in a position corresponding to one end of the pressure chamber, a lower substrate in which a nozzle, through which the ink is to be ejected, is formed in a position, is provided on the top surface of the intermediate substrate; which corresponds to the damper and a piezoelectric actuator which is monolithically formed on the upper substrate and which provides a driving force for ejecting ink to the pressure chamber. A throttle connecting the other end of the pressure chamber to the ink reservoir is formed on at least one side of the lower surface of the upper substrate and the upper surface of the intermediate substrate, and the lower substrate, the intermediate substrate and the upper substrate are sequentially stacked and adhere to each other wherein the three substrates are formed of a monocrystalline silicon substrate.
In an embodiment The present invention is a part which has an upper wall of the pressure chamber of the upper substrate forms, as a vibration plate, by dowries the piezoelectric actuator is deformed.
Here For example, it is preferable that the upper substrate be made of a silicon-on-insulator (SOI) wafer is formed, which has a structure in which a first silicon substrate, an intermediate oxide layer and a second silicon substrate are stacked sequentially and the pressure chamber is formed on the first silicon substrate and the second silicon substrate serves as the vibration plate.
It is also preferred that the pressure chamber in two columns too is disposed on both sides of the ink reservoir, and in this Case is a barrier wall in the reservoir in the longitudinal direction of the ink reservoir formed to divide the ink reservoir in the vertical direction.
As well is a silicon oxide layer between the upper substrate and the piezoelectric actuator formed. Here suppressed the Silicon oxide layer a material diffusion and thermal stress between the upper substrate and the piezoelectric actuator.
It It is also preferable that the piezoelectric actuator has a bottom electrode formed on the upper substrate, a piezoelectric layer on the lower electrode designed so that it is on an upper Part of the pressure chamber is placed, and an upper Elektode, the is formed on the piezoelectric layer and to the piezoelectric Layer applies a voltage includes.
Here the lower electrode has a two-layered structure, in a Ti layer and a Pt layer are stacked on top of each other, and the Ti layer and the Pt layer as a common electrode of the serve piezoelectric actuator and also as a diffusion barrier serve the diffusion between the upper substrate and the piezoelectric Layer prevented.
It It is also preferable that the nozzle has an opening formed in a lower one Part of the lower substrate and an ink induction part, which in one upper part of the lower substrate is formed and the damper with the opening connects, includes.
Here it is also preferred that the cross-sectional area of the Ink induction part from the damper to the opening gradually reduces, and the ink induction part in a quadrangular pyramid shape is trained.
As well the throttle may have a rectangular cross-section.
however the throttle has a T-shaped cross-section on and off of the top of the intermediate substrate is deep in one formed in the vertical direction.
According to one Another aspect of the present invention is a method for Preparation of a piezoelectric inkjet printhead provided. The method includes preparing an upper substrate, a Intermediate substrate and a lower substrate made of a monocrystalline Silicon substrate are formed, micromachining the upper substrate, of the intermediate substrate and the lower substrate, respectively, so that an ink passage is formed, layering of the lower substrate, the intermediate substrate and the upper substrate in each of which the ink passage is formed was so that the lower substrate, the intermediate substrate and the Adhere upper substrate to each other, and forming a piezoelectric actuator on the upper substrate, which provides a driving force for ink ejection.
The Method comprises, prior to forming the ink passage, forming a base mark on each of the three substrates, so that the three substrates are aligned when adhering the three substrates, and before forming the piezoelectric actuator, forming a silicon oxide layer on the upper substrate.
Preferably, forming the ink passage includes forming a pressure chamber to be filled with ink to be ejected and an ink supply passage through which ink is supplied on the underside of the upper substrate, forming a throttle having one end of the pressure merge, at least on one side of the underside of the upper substrate and the top of the intermediate substrate, forming a damper, which is connected to the other end of the pressure chamber, in the intermediate substrate, forming an ink reservoir, whose one end is connected to the ink supply passage, and one side of which is connected to the throttle, on top of the intermediate substrate, and forming a nozzle, which is connected to the damper, in the lower substrate.
Prefers are formed in forming the pressure chamber and the ink supply passage a silicon-on-insulator (SOI) wafer having a structure in which a first silicon substrate, an intermediate oxide layer, and a second one Silicon substrate sequentially on top of each other layered, used as the upper substrate and the first one Silicon substrate using the intermediate oxide layer as Ätzstopschicht etched whereby the pressure chamber and the ink supply passage formed become.
At the Forming the choke will be the bottom of the upper substrate or the top of the intermediate substrate is dry etched or wet etched. however The throttle may be formed by forming part of the throttle on the Bottom of the upper substrate and forming the other part the choke are formed on top of the intermediate substrate.
As well At the time of forming the reactor, the top of the intermediate substrate becomes to a certain depth by dry etching using inductive coupled plasma (ICP), whereby the throttle with a T-shaped Cross section is formed.
In In this case, the formation of the throttle and the formation of the Ink reservoirs performed simultaneously.
Prefers includes forming the damper Forming a depression with a certain depth, with the connected to the other end of the pressure chamber, on top of the intermediate substrate, and perforating the recess, causing the damper connected to the other End of the pressure chamber is formed.
Here the formation of the depression is submerged by sandblasting or dry etching Use of inductively coupled plasma (ICP), and Perforation of the well is by dry etching using ICP carried out. Prefers the perforation of the depression will be simultaneous with the formation carried out of the ink reservoir.
Prefers When forming the ink reservoir, the top of the intermediate substrate becomes dry etched to a certain depth, eliminating the ink reservoir is trained.
Prefers The forming of the nozzle comprises dry etching the nozzle Top of the lower substrate to a certain depth, so that forming an ink induction part connected to the damper, and etching the Bottom of the lower substrate, so that an opening connected to the ink induction part is trained.
Preferably, in forming the ink-inducing part, the lower substrate is formed by using a silicon substrate having a crystal surface in the direction (FIG. 100 ) is anisotropically wet-etched as the lower substrate, thereby forming the ink-inducing member having a quadrangular pyramidal shape.
Prefers When adhering, the coating of the three substrates is used performed a mask aligning device and the adhesion of the three Substrates are prepared using a silicon direct bond (SDB) process carried out. When adhering, it is preferred to improve the adhesive property of the three substrates, the three substrates in a state with each other in which silicon oxide layers on at least one underside of the upper substrate and an upper surface of the lower substrate are.
Prefers The forming of the piezoelectric actuator comprises sequential Coating a Ti layer and a Pt layer on the upper substrate, so that a lower electrode is formed, forming a piezoelectric layer on the lower electrode and forming an upper electrode on the piezoelectric layer.
The Forming the piezoelectric layer further comprises, after forming of the upper electrode, dividing the adherent three substrates in Chip units and applying an electric field to the piezoelectric Layer of the piezoelectric actuator, so that piezoelectric Properties are generated.
At the Forming the piezoelectric layer becomes a piezoelectric layer Material in pasty Condition applied to the lower electrode in a position which corresponds to the pressure chamber, and then sintered, causing the piezoelectric layer is formed, and the coating of the piezoelectric material is performed by screen printing. Prefers will, while sintering the piezoelectric material, an oxide layer on one Inner wall of the ink passage formed at the three substrates is trained. The sintering can be done before cutting or after Parting done become.
According to one Another aspect of the present invention is a piezoelectric Inkjet printhead available posed. The piezoelectric ink-jet printhead includes an ink reservoir in which ink supplied from an ink tank is contained with ejected ink filled Pressure chamber, a throttle, which the ink reservoir with the pressure chamber connects, a nozzle, is ejected from the pressure chamber by the ink, and a piezoelectric Actuator, which is a driving force for ejecting ink to the pressure chamber provides. The throttle has a T-shaped cross-section and is designed so that it is widely formed in a vertical direction is.
According to the above The present invention referred to become elements which undergo ink passage form, such as an ink reservoir and the pressure chamber, on three silicon substrates formed using a micromachining technology, which makes the elements precise and easily formed to a fine dimension on each of the three substrates can be. There as well the three substrates are formed of silicon are adhesion properties up to each other. Further, the number of substrates is compared reduced to the prior art, creating a manufacturing process is simplified and alignment errors are reduced.
The Above and other aspects and advantages of the present invention will be better understood from a detailed description of preferred embodiments with reference to the accompanying drawings, in which:
1 Fig. 16 is a cross-sectional view illustrating a typical structure of a conventional piezoelectric ink-jet printhead;
2 Fig. 11 is an exploded perspective view illustrating a conventional piezoelectric ink jet printhead;
3 a cross-sectional view of the conventional piezoelectric ink-jet printhead in the longitudinal direction of a pressure chamber of 2 is;
4 a cross-sectional view along the line AA of 3 is;
5 Fig. 11 is an exploded perspective sectional view illustrating an embodiment of a piezoelectric ink-jet printhead according to the present invention;
6A FIG. 12 is a cross-sectional view showing the embodiment of the piezoelectric ink jet printing head in the longitudinal direction of a pressure chamber of FIG 5 represents;
6B an enlarged cross-sectional view along the line BB 'of 6A is;
7 Fig. 11 is an exploded perspective view illustrating another embodiment of the piezoelectric ink-jet printhead having a T-shaped throttle according to the present invention;
8A to 8E Cross-sectional views illustrating the step of forming a base mark on an upper substrate in a method of manufacturing the piezoelectric ink-jet printhead according to the present invention;
9A to 9G Are cross-sectional views illustrating the step of forming the pressure chamber on the upper substrate;
10A to 10E Are cross-sectional views illustrating the step of forming a reactor on an intermediate substrate;
11A to 11J Are cross-sectional views illustrating a first method of forming an ink reservoir and a damper on the intermediate substrate in a stepwise manner;
12A and 12B Are cross-sectional views illustrating a second method of forming the ink reservoir and the damper on the intermediate substrate in a stepwise manner;
13A to 13H Are cross-sectional views illustrating the step of forming a nozzle on a lower substrate;
14 Fig. 12 is a cross-sectional view illustrating a step of sequentially laminating the lower substrate, the intermediate substrate, and the upper substrate and adhering the substrates to each other; and
15A and 15B 3 are cross-sectional views illustrating a step for completing the piezoelectric ink-jet printhead according to an embodiment of the present invention by forming a piezoelectric actuator on the upper substrate.
Hereinafter, the present invention will be described in detail by describing preferred embodiments of the invention with reference to the accompanying drawings. However, this invention may be embodied in many different forms and should not be construed as being herein Embodiments are considered limited. Like reference numerals refer to like elements having the same functions and the dimension and thickness of an element may be increased for clarity of illustration. It should be understood that when a layer is described as being on another layer or substrate, it may be directly on top of the other layer or substrate, or intermediate layers may also be present.
5 Fig. 10 is an exploded perspective sectional view illustrating an embodiment of a piezoelectric ink-jet printhead according to the present invention; 6A FIG. 12 is a cross-sectional view showing the embodiment of the piezoelectric ink-jet printing head in the longitudinal direction of a pressure chamber of FIG 5 represents, and 6B is an enlarged cross-sectional view along the line BB 'of 6A ,
Related to the 5 . 6A and 6B form layers of three substrates 100 . 200 and 300 and adhering the substrates to each other, a piezoelectric ink-jet printhead according to the above-mentioned embodiment of the present invention. Elements that form an ink passage are on each of the three substrates 100 . 200 and 300 formed and a piezoelectric actuator 190 for generating a driving force for ink ejection is on the upper substrate 100 intended. In particular, the three substrates 100 . 200 and 300 formed from a monocrystalline silicon wafer. Thus, the elements forming an ink passage can be precisely and easily made to have a fine size in each of the three substrates 100 . 200 and 300 using micromachining technology such as photolithography or etching.
The ink passage includes an ink supply passage 110 , through which ink is supplied from an ink tank (not shown), an ink reservoir 210 in which passes through the ink supply passage 110 Contains flowed ink, a throttle 220 for supplying ink from the ink reservoir 210 to a pressure chamber 120 , the pressure chamber 120 filled with ink to be ejected for generating a pressure change for ink ejection, and a nozzle 310 through which ink is ejected. Likewise, a damper 230 , one in the pressure chamber 120 through the piezoelectric actuator 190 generated energy and attenuates a rapid pressure change, between the pressure chamber 120 and the nozzle 310 be educated. As described above, the elements constituting the ink passage are each of the three substrates 100 . 200 and 300 assigned and are on each of the three substrates 100 . 200 and 300 educated.
The pressure chamber 120 with a certain depth is on the bottom of the upper substrate 100 formed and the ink supply passage 110 a through hole is on one side of the upper substrate 100 educated. The pressure chamber 120 is formed in the form of a flow direction of the ink longer cuboid and is in two columns on both sides of the ink reservoir 210 formed on the intermediate substrate 200 is trained. The pressure chamber 120 however, it can only be in one column on one side of the ink reservoir 210 be educated.
The upper substrate 100 is formed of a monocrystalline silicon wafer used in the production of integrated circuits (ICs), and is particularly preferably formed of a silicon-on-insulator (SOI) wafer. In general, the SOI wafer has a structure in which a first silicon substrate 101 , an intermediate oxide layer 102 that on the first substrate 101 is formed, and a second silicon substrate 103 that on the intermediate oxide layer 102 attached, sequentially stacked. The first silicon substrate 101 is formed of monocrystalline silicon and has a thickness of about several tens to several hundred μm. Oxidize the surface of the first silicon substrate 101 can the intermediate oxide layer 102 form and the thickness of the intermediate oxide layer 102 is about several hundred Å to 2 μm. The second silicon substrate 103 is also formed of monocrystalline silicon and its thickness is about several microns to several tens of microns. The reason for using SOI wafers as the upper substrate 100 lies in the fact that the height of the pressure chamber 120 can be adjusted precisely. That is, because the intermediate oxide layer 102 , which forms an intermediate layer of the SOI wafer, serves as an etch stop layer when the thickness of the first silicon substrate 101 is determined, the height of the pressure chamber 102 determined accordingly. The second silicon substrate 103 , which is an upper wall of the pressure chamber 120 is formed by the piezoelectric actuator 190 deformed, creating it as a vibration plate for changing the volume of the pressure chamber 120 serves. The thickness of the vibrating plate is also determined by the thickness of the second silicon substrate 103 certainly. This will be described later in more detail.
The piezoelectric actuator 190 is monolithic on the upper substrate 100 educated. A silicon oxide layer 180 is between the upper substrate 100 and the piezoelectric actuator 190 educated. The silicon oxide layer 180 serves as an insulating layer, suppressing material diffusion between the upper substrate 100 and the piezoelectric actuator 190 and sets thermal load. The piezoelectric actuator 190 includes lower electrodes 191 and 192 that as common Serving electrode, a piezoelectric layer 193 which is deformed by an applied voltage, and an upper electrode 194 , which serves as a drive electrode. The lower electrodes 191 and 192 are on the entire surface of the silicon oxide layer 180 are formed and are preferably formed from two metallic thin films, such as a Ti layer 191 and a Pt layer 192 , The Ti layer 191 and the Pt layer 192 serve as a common electrode and further serve as a diffusion barrier layer, the diffusion between the piezoelectric layer formed above 193 and the upper substrate formed thereunder 100 prevented. The piezoelectric layer 193 is on the lower electrodes 191 and 192 is formed and is on an upper part of the pressure chamber 120 placed. The piezoelectric layer 193 is deformed by an applied voltage and serves to deform the second silicon substrate 103 , ie the vibration plate, of the upper substrate 100 that is the top wall of the pressure chamber 102 forms. The upper electrode 194 is on the piezoelectric layer 193 formed and serves as a drive electrode for applying a voltage to the piezoelectric layer 193 ,
That with the ink supply passage 110 connected ink reservoir 210 is formed to a certain depth and leaving it on top of the intermediate substrate 200 is longer, and the throttle 220 for connecting the ink reservoir 210 with one end of the pressure chamber 120 is flatter. The damper 230 is vertical in the intermediate substrate 200 formed in a position that the other end of the pressure chamber 120 equivalent. The cross section of the damper 230 may be formed in a circular or polygonal shape. As described above, when the pressure chamber 120 in two columns on both sides of the ink reservoir 210 is disposed, is the ink reservoir 210 divided into two parts by a barrier wall 215 in the ink reservoir 210 in the longitudinal direction of the ink reservoir 210 is trained. This is preferable to smoothly supply ink and disturbances between the ones on both sides of the ink reservoir 210 arranged pressure chambers 120 to avoid. The throttle 220 serves as a passage through the ink from the ink reservoir 120 to the pressure chamber 120 is supplied and also serves to prevent ink from the pressure chamber 120 to the ink reservoir 210 flows back when ink is ejected. To prevent backflow of ink, the cross-sectional area of the restrictor is 220 much smaller than the cross-sectional areas of the pressure chamber 120 and the damper 230 and is in a range in which the amount of ink in a suitable manner to the pressure chamber 120 is supplied.
Meanwhile, the throttle became 220 as on top of the intermediate substrate 200 shown and described trained. The throttle 220 however, although not shown, may be on the underside of the upper substrate 100 be formed, or part of the throttle 220 can be on the bottom of the top substrate 100 and the other part of it may be on top of the intermediate substrate 200 be educated. In the latter case, adhesion of the upper substrate results 100 at the intermediate substrate 200 for complete expansion of the throttle 220 ,
The nozzle 310 is on the lower substrate 300 formed in a position that the damper 230 equivalent. The nozzle 310 is from an opening 312 at the lower part of the lower substrate 300 is formed and ejected by the ink, and an ink induction part 311 that is in an upper part of the lower substrate 300 is formed, the damper 230 with the opening 312 connects and pressurizes ink and ink from the damper 230 to the opening 312 induced, formed. The opening 312 is formed in a vertical recess with a certain diameter and the ink induction part 311 is formed in a quadrangular pyramid shape in which the area of the ink induction part 311 gradually from the damper 230 to the opening 312 is reduced. Meanwhile, the ink induction part 311 be formed in a conical shape. However, as will be described later, it is preferable that the ink induction part 311 which has a quadrangular pyramid shape on the lower substrate formed of a monocrystalline silicon wafer 300 is trained.
As previously described, the three substrates are 100 . 200 and 300 layered on each other and adhere to each other, whereby the piezoelectric ink-jet printhead is formed according to the present invention. The ink passage in which the ink supply passage passes 110 , the ink reservoir 210 , the throttle 220 , the pressure chamber 120 , the damper 230 and the nozzle 310 connected in sequence is in the three substrates 100 . 200 and 300 educated.
The Operation of the piezoelectric ink-jet printhead according to the present invention Invention having the above structure will be described below.
The ink reservoir 210 through the ink supply passage 110 ink supplied from the ink tank (not shown) becomes the pressure chamber 120 through the throttle 220 fed. When the pressure chamber 120 filled with ink and a voltage to the piezoelectric layer 193 through the upper electrode 194 from the piezoelectric actuator 190 is applied, the piezoelectric layer 193 deformed. Such becomes the second silicon substrate 103 of the upper substrate 100 , which serves as a vibration plate, bent down. Due to the bending deformation of the second silicon substrate 103 , becomes the volume of the pressure chamber 120 decreased and due to an increase in the pressure in the pressure chamber 120 , ink is in the pressure chamber 120 through the nozzle 310 over the damper 230 pushed out. In this case there is an increase in pressure in the pressure chamber 120 to the damper 230 with a cross-sectional area wider than the cross-sectional area of the throttle 220 concentrated. In this way, most of the ink is in the pressure chamber 120 to the damper 230 and it prevents ink from passing through the throttle 220 to the ink reservoir 210 flows back. Ink passing through the damper 230 at the nozzle 310 arrives is through the ink induction part 311 pressurized, and then the ink gets through the opening 312 pushed out.
Subsequently, when the on the piezoelectric layer 193 the piezoelectric actuator 190 applied voltage is interrupted, the piezoelectric layer 193 returned to its original state, whereby the second silicon substrate 103 , which serves as a vibration plate, is restored to its original state, and the volume of the pressure chamber 120 increases. Due to a decrease in the pressure in the pressure chamber 120 , flows in the ink reservoir 210 contained ink through the throttle 220 to the pressure chamber 120 , causing the pressure chamber 120 is refilled with ink.
Meanwhile 7 another embodiment of the piezoelectric ink-jet printhead with a T-shaped throttle according to the present invention. Here, like reference numerals denote 5 Elements with the same function.
As in 7 As shown, the present embodiment is the exception of the reactor 220 ' same as the embodiment of 5 , Therefore, descriptions of the same elements are omitted and only differences are described below.
In reference to 7 has the throttle 220 ' for supplying ink from the ink reservoir 210 to the pressure chamber 120 a T-shaped cross section and is from the top of the intermediate substrate 200 formed deep in a vertical direction. The depth of the throttle 220 ' may be equal to or less than the depth of the ink reservoir 210 , Equally, the throttle points 220 ' compared to the throttle 220 from 5 a very large depth, and thus the total volume is more increased than the volume of the throttle 220 from 5 , In this way, a volume fluctuation between the pressure chamber 120 and the throttle 220 ' reduced. According to the throttle 220 ' is the flow resistance of the ink reservoir 210 to the pressure chamber 120 supplied ink and a pressure loss in the step of supplying ink through the throttle 220 ' is reduced. Thus, a flow amount that is the throttle 220 ' goes through, so increases that ink smoothly and faster in the pressure chamber 120 is refilled. Consequently, even when the ink-jet printhead is operated in a high frequency range, uniform ink ejection volume and ink ejection speed can be achieved.
Meanwhile, as described above, the throttle 220 ' T-section cross section also in ink jet printheads having structures other than the piezoelectric ink jet printhead having the structure of FIG 7 be used.
Hereinafter, a method of manufacturing the piezoelectric ink-jet printhead according to the present invention will be described with reference to the accompanying drawings. Hereinafter, the method based on the piezoelectric ink-jet printhead having the structure of FIG 5 described. And, a method of manufacturing the piezoelectric ink-jet printhead having the structure of 7 according to the present invention will be described only in the step of forming a throttle.
Summarized, three substrates such as an upper substrate, an intermediate substrate and a lower substrate in which elements for forming an ink passage be formed, are produced accordingly, and then the three substrates are stacked and stick together and finally a piezoelectric actuator is formed on the upper substrate, whereby the piezoelectric ink-jet printhead according to the present invention Invention is completed. Meanwhile, steps can be taken to manufacture regardless of the order of the upper, middle and lower substrates Substrates performed become. This means, the lower substrate or the intermediate substrate can be prepared first, or two or all three substrates can be made simultaneously become. For simplicity, the steps to manufacture of the upper substrate, the intermediate substrate and the lower substrate described sequentially below. As previously described, the throttle can the underside of the upper substrate or at the top of the intermediate substrate be formed, or part of the throttle can be both on the bottom of the upper substrate as on top of the lower substrate be formed. However, in the following, to avoid it, it is more complex Descriptions are shown showing that the choke is on top of the intermediate substrate is trained.
The 8A to 8E FIG. 15 is cross-sectional views showing a step of forming a base mark on an upper substrate in a method of manufacturing the piezoelectric Tin. FIG tenstrahldruckkopfes represent according to the present invention.
In reference to 8A is the upper substrate in the present embodiment 100 formed from a monocrystalline silicon substrate. This is because a silicon wafer, which is widely used for manufacturing semiconductor devices, can be used without any changes, thereby being effective in mass production. The thickness of the upper substrate 100 is about 100 to 200 microns, preferably about 130 to 150 microns and can be suitably by the height of the pressure chamber ( 120 in 5 ), which are on the bottom of the upper substrate 100 is designed to be determined. It is preferable that the SOI wafer is used as the upper substrate 100 is used because the height of the pressure chamber ( 120 in 5 ) can be formed precisely. As described above, the SOI wafer has a structure in which the first silicon substrate 101 on the first silicon substrate 101 formed intermediate oxide layer 102 and that on the intermediate oxide layer 102 adherent second silicon substrate 103 sequentially stacked. In particular, the second silicon substrate 103 has a thickness of several or several tens of μm in order to optimize the thickness of the vibrating plate.
When the upper substrate 100 is placed in an oxidation furnace and is wet or dry oxidized become the upper and lower sides of the upper substrate 100 oxidized, creating silicon oxide layers 151a and 151b be formed.
Thereafter, a photoresist (PR) is applied to the surface of the silicon oxide layers 151a respectively. 151b applied to the top and bottom of the top substrate 100 are trained, as in 8B shown. Subsequently, the applied photoresist (PR) is developed, whereby an opening 141 for forming a base mark in the region of an edge of the upper substrate 100 is formed.
Thereafter, a part of the silicon oxide layers 151a and 151b passing through the opening 141 is wet etched using the PR as an etch mask and removed, leaving the top substrate 100 is partially uncovered and then the PR is deducted as it is in 8C is shown.
Thereafter, the exposed portion of the upper substrate becomes 100 to a certain depth using the silicon oxide layers 151a and 151b wet etched as an etch mask, creating a base mark 140 is formed as it is in 8D is shown. If in this case the upper substrate 100 For example, tetramethylammonium hydroxide (TMAH) or KOH may be used as the silicon etchant.
After the base mark 140 is formed, the remaining silicon oxide layers 151a and 151b removed by wet etching. This is to purify foreign particles, such as by-products, which occur when the above steps are performed, simultaneously with the silicon oxide layers 151a and 151b be removed.
This will be the upper substrate 100 in which the base mark 140 in the area of the edge of the top and bottom of the upper substrate 100 is trained, prepared as it is in 8E is shown.
When the upper substrate 100 , an intermediate substrate and a lower substrate, which will be described later, are stacked and adhere to each other, becomes the base mark 140 for aligning the upper substrate 100 , the intermediate substrate and the lower substrate. In this way, in the case of the upper substrate 100 the base mark 140 only on the underside of the upper substrate 100 be educated. In addition, if another alignment method or device is used, the base marker may be used 140 not necessary, and in this case, the above steps are not performed.
The 9A to 9G FIG. 15 are cross-sectional views illustrating a step of forming the pressure chamber on the upper substrate. FIG.
The upper substrate 100 is placed in the oxidation furnace and oxidized wet or dry, resulting in silica layers 152a and 152b on the top and bottom of the upper substrate 100 be formed as in 9A shown. In this case, the silicon oxide layer 152b only on the underside of the upper substrate 100 be formed.
Thereafter, a photoresist (PR) is applied to the surface of the silicon oxide layer 152b applied on the underside of the upper substrate 100 is formed, as in 9B shown. Subsequently, the applied photoresist (PR) is developed, whereby an opening 121 for forming a pressure chamber having a certain depth on the underside of the upper substrate 100 is formed.
Thereafter, a part of the silicon oxide layer 152b passing through the opening 121 is exposed, using the photoresist (PR) as an etching mask by dry etching, such as reactive ion etching (RIE) removed, eliminating the underside of the upper substrate 100 partially exposed, as in 9C shown. In this case, the silicon oxide layer 152b also be removed by wet etching.
Thereafter, the exposed portion of the upper substrate becomes 100 etched to a certain depth using the photoresist (PR) as an etch mask, creating a pressure chamber 120 is formed as in 9D shown. In this case, a dry etching process of the upper substrate 100 using inductively coupled plasma (ICP). As in 9D is shown when an SOI wafer as the upper substrate 100 is used, serves an intermediate oxide layer formed on an SOI wafer 102 as the etch stop layer, and thereby only the first silicon substrate is formed in this step 101 etched. Therefore, with the thickness of the first silicon substrate 101 , the pressure chamber 102 be set precisely to a desired height. The thickness of the first silicon substrate 101 can be easily adjusted in a wafer polishing process. Meanwhile, the second silicon substrate serves 103 , which is an upper wall of the pressure chamber 120 forms, as a vibrating plate, as described above, and the thickness of the second silicon substrate 103 can be easily adjusted in a wafer polishing process.
When the photoresist (PR) is peeled off after the pressure chamber 120 is formed, is the upper substrate 100 prepared as in 9E shown. In this state, however, impurity particles such as by-products or polymer which occur in the above-mentioned wet etching or RIE or dry etching with ICP may be formed on the surface of the upper substrate 100 lie. Therefore, for removing these foreign substance particles, it is preferable that the entire surface of the upper substrate 100 using sulfuric acid solution or TMAH. In this case, the remaining silicon oxide layers become 152a and 152b removed by wet etching and a part of the intermediate oxide layer 102 of the upper substrate 100 ie a part of the upper wall of the pressure chamber 120 is also removed.
Such is the upper substrate 100 in which the base mark 140 in the area of the edge of the top and bottom of the upper substrate 100 is formed and the pressure chamber 120 on the underside of the upper substrate 100 is trained, prepared, as in 9F shown.
As described above, the upper substrate becomes 100 dry etched using the photoresist (PR) as an etch mask, reducing the pressure chamber 120 is formed, and the photoresist (PR) is subtracted. However, the PR can be subtracted and then the upper substrate 100 using the silicon oxide layer 152b be etched dry as an etching mask, causing the pressure chamber 120 is formed. That is, if the on the bottom of the upper substrate 100 formed silicon oxide layer 152b is comparatively thin, it is preferable that the photoresist (PR) is not stripped and an etching process is performed to the pressure chamber 120 to build. When the silicon oxide layer 152b is relatively thick, the photoresist (PR) is peeled off and then an etching process is performed to the pressure chamber 120 using the silicon oxide layer 152b to form as an etching mask.
It can be silicon oxide layers 153a and 153b again on the top and bottom of the upper substrate 100 from 9F be formed as in 9G shown. In this case, the intermediate layer becomes 102 , part of which is in the 9F shown step, through the silicon oxide layer 153b compensated. Similarly, if the silicon oxide layers 153a and 153b a step of forming a silicon oxide film 180 as an insulating layer on the upper substrate 100 in the step of 15A be omitted, which will be described later. In addition, if the silicon oxide layer 153b inside the pressure chamber 120 is formed to form an ink passage, the silicon oxide layer is reacted 153b , because of the characteristics of the silicon oxide film 153b , with almost all types of inks and therefore a variety of inks can be used.
Meanwhile, although not shown, the ink supply passage ( 110 in 5 ) also together with the pressure chamber 120 in the in the 9A to 9G formed steps shown. That is, in the 9G shown step, the ink supply passage ( 110 in 5 ) with the same depth as a certain depth of the pressure chamber 120 on the underside of the upper substrate 100 together with the pressure chamber 120 educated. The to the specific depth at the bottom of the upper substrate 100 formed ink supply passage ( 110 in 5 ) is penetrated using a pointed tool such as a needle after all manufacturing processes are completed.
The 10A to 10E FIG. 15 are cross-sectional views illustrating a step of forming a reactor on an intermediate substrate. FIG.
In reference to 10A is an intermediate substrate 200 formed from a monocrystalline silicon substrate and the thickness of the intermediate substrate 200 is about 200 to 300 microns. The thickness of the intermediate substrate 200 can suitably be determined by the depth of the ink reservoir ( 210 from 5 ), that on the intermediate substrate 200 is formed, and the length of the penetrated damper ( 230 from 5 ) be determined.
A base mark 240 is in the region of an edge of the upper and lower sides of the intermediate substrate 200 educated. Steps for forming the base mark 240 on the intermediate substrate 200 are the same as they are in the 8A to 8E are shown and are therefore not shown separately and their descriptions are omitted.
If the intermediate substrate 200 in which the base mark 240 is formed, placed in the oxidation furnace and wet or dry etched, the top and bottom of the intermediate substrate 200 oxidized, creating silicon oxide layers 251a and 251b be formed as in 10A is shown.
Thereafter, a photoresist (PR) is applied to the surface of the top of the intermediate layer 200 formed silicon oxide layer 251a applied as in 10B shown. Subsequently, the applied photoresist (PR) is developed, whereby an opening 221 for forming a choke on top of the intermediate substrate 200 is formed.
Thereafter, a part of the silicon oxide layer 251a passing through the opening 221 is etched wet using the photoresist (PR) as an etch mask and removed, leaving the top of the intermediate substrate 200 is partially exposed, and then the photoresist (PR) is peeled off as in 10C shown. In this case, the silicon oxide layer 251a not by wet etching, but by dry etching, such as RIE.
Thereafter, the exposed part of the intermediate substrate becomes 200 using the silicon oxide layer 251a wet or dry etched to a certain depth as an etching mask, creating a choke 220 is formed as in 10D shown. In this case, if the intermediate substrate 200 wet etched, for example, tetramethylammonium hydroxide (TMAH) or KOH can be used as silicon etchant.
Subsequently, when the remaining silicon oxide layers 251a and 251b removed by wet etching, the intermediate substrate 200 in which the throttle 220 in the region of the edge of the top and bottom of the intermediate substrate 200 is formed, prepared, as in 10E shown.
Meanwhile, the in 7 shown T-shaped throttle in the above steps is not formed. That is, in this case, in the above steps, only the base mark becomes 240 on the intermediate substrate 200 educated. And the T-shaped restrictor may be used together with an ink reservoir using the same method as a method of forming an ink reservoir in the following steps.
The 11A to 11J FIG. 15 are cross-sectional views illustrating a first method of forming an ink reservoir and a damper on the intermediate substrate in a stepwise manner. FIG.
The intermediate substrate 200 is placed in the oxidation furnace and wet or dry etched, resulting in silica layers 252a and 252b on the top and bottom of the intermediate substrate 200 be formed as in 11A shown. In this case, the silicon oxide layer 252a be formed in a part where the throttle 220 is formed.
Thereafter, a photoresist (PR) is applied to the surface of the top of the intermediate substrate 200 formed silicon oxide layer 252a applied as in 11B shown. Subsequently, the applied photoresist (PR) is developed, whereby an opening 211 for forming an ink reservoir on top of the intermediate substrate 200 is formed. In this case, the photoresist (PR) remains in a part where a barrier wall is to be formed in the ink reservoir.
After that, part of the through the opening 211 exposed silicon oxide layer 252a removed by wet etching using the photoresist (PR) as an etching mask, whereby the top of the intermediate substrate 200 partially exposed, as in 11C shown. In this case, the silicon oxide layer 252a not removed by wet etching, but by dry etching, such as RIE.
Subsequently, after the photoresist (PR) is peeled off, the intermediate substrate 200 formed as in 11D shown. Only part of the top of the intermediate substrate 200 in which the ink reservoir is to be formed is exposed and another part thereof is with the silicon oxide layers 252a and 252b covered.
Thereafter, the photoresist (PR) is again applied to the surface of the silicon oxide layer 252a applied to the top of the intermediate substrate 200 is formed, as in 11E shown. In this case, the exposed part becomes the surface of the intermediate substrate 200 also covered with photoresist (PR). Subsequently, the applied photoresist (PR) is developed, whereby an opening 231 for forming a damper on top of the intermediate substrate 200 is formed.
After that, part of the through the opening 231 exposed silicon oxide layer 252a wet etched using the photoresist (PR) as an etch mask, whereby the surface of the intermediate substrate 200 in which the damper is to be formed, partially exposed, as in 11F shown. In this case, the silicon oxide layer 252a not removed by wet etching, but by dry etching, such as RIE.
Subsequently, the exposed part of the intermediate substrate 200 using the Pho toresist (PR) as an etching mask etched to a certain depth, creating a depression 232 is formed as a damper. In this case, the etching of the intermediate substrate 200 be carried out by dry etching with ICP.
Thereafter, when the photoresist (PR) is peeled off, the portion of the surface of the intermediate substrate 200 in which the ink reservoir is to be formed, exposed again as in 11H shown.
Subsequently, after the exposed portion of the top surface of the intermediate substrate 200 and the underside of the recess forming the damper 232 using the silicon oxide layer 252a etched dry as an etching mask, a damper 230 through which the intermediate substrate 200 runs, and the ink reservoir 210 formed with the particular depth, as in 11I shown. There will also be a barrier wall 252 that the ink reservoir 210 divided in the vertical direction, in the ink reservoir 210 educated. In this case, etching of the intermediate substrate 200 be carried out by dry etching with ICP.
Thereafter, the remaining silicon oxide layers 252a and 252b be removed by wet etching. This is for the purification of impurity particles, such as by-products, which occur when the above steps are carried out, at the same time the silicon oxide layers 252a and 252b be removed.
This is how the intermediate substrate becomes 200 in which the base mark 240 , the throttle 220 , the ink reservoir 210 , the barrier wall 215 and the damper 230 are trained, prepared, as in 11J shown.
Meanwhile, although not shown, a silicon oxide layer may be again on the entire top and bottom of the intermediate substrate 200 from 11J be formed.
The 12A and 12B FIG. 15 are cross-sectional views illustrating a second method of forming the ink reservoir and the damper on the intermediate substrate in a stepwise manner. The second method described below is similar to the first method except for a step of forming a damper. Therefore, only parts other than the above-mentioned first method will be described below.
In the second method, the steps that expose only the part in which the ink reservoir is to be formed are on the top side of the intermediate substrate 200 same as they are in the 11A to 11D are shown.
Thereafter, the photoresist (PR) is applied to the surface of the top of the intermediate substrate 200 formed silicon oxide layer 252a applied as in 12A shown. In this case, the photoresist (PR) in a dry film form is applied to the surface of the silicon oxide film 252a applied using a lamination process with heating, pressurization and compression processes. The photoresist (PR) in dry film form serves as a protective layer for protecting further portions of the intermediate substrate 200 in a sandblasting process, which will be described later. Subsequently, the applied photoresist (PR) is developed, whereby the opening 231 is formed to form a damper.
Subsequently, when passing through the opening 231 exposed silicon oxide layer 252a and the intermediate substrate 200 to a certain depth below the silicon oxide layer 252a removed by sandblasting, a recess 232 formed to form a damper, as in 12B shown.
The next steps are the same as those in the 11H to 11J of the first method are shown.
In this way, the second method differs from the first method in that the recess 232 for the damper is not formed by dry etching, but by sandblasting. That is, to the depression 232 for the damper, in the first method, the silicon oxide layer 252a etched and then the intermediate substrate 200 etched to a certain depth, but the second method is the silicon oxide layer 252a and the intermediate substrate 200 with the specific depth removed by sandblasting at once. Therefore, the number of processes in the second method can be reduced as compared with the number of processes in the first method, thereby also reducing the overall processing time.
The 13A to 13H FIG. 15 are cross-sectional views illustrating a step of forming a nozzle in a lower substrate. FIG.
In reference to 13A is a lower substrate 300 formed from a monocrystalline silicon substrate and the thickness of the lower substrate 300 is about 100 to 200 microns.
A base mark 340 is in the area of one edge of the top and bottom of the lower substrate 300 educated. Steps for forming the base mark 340 on the lower substrate 300 are the same as in the 8A to 8E and therefore descriptions are omitted.
If the lower substrate 300 in which the base mark 340 is formed, placed in the oxidation furnace and wet or dry etched, the top and bottom of the lower substrate 300 oxidized, creating silicon oxide layers 351a and 351 be formed as in 13A shown.
Thereafter, a photoresist (PR) is applied to the surface of the silicon oxide layer 351a applied on top of the lower substrate 300 is formed, as in 13B shown. Subsequently, the applied photoresist (PR) is developed, creating an opening 315 for forming an ink-inducing part of a nozzle on the upper surface of the lower substrate 300 is formed. The opening 315 is formed in a position that on the intermediate substrate 200 trained damper 230 corresponds, as in 11J shown.
Thereafter, a part of the silicon oxide layer 351a passing through the opening 315 is etched wet using the photoresist (PR) as an etch mask and removed, leaving the top of the bottom substrate 300 is partially exposed, and then the photoresist (PR) subtracted, as in 13C shown. In this case, the silicon oxide layer 351a not by wet etching, but by dry etching, such as RIE.
Thereafter, the exposed part of the lower substrate becomes 300 using the silicon oxide layer 351a wet etched to a certain depth as an etch mask, thereby forming an ink induction part 311 is formed as in 13D shown. In this case, if the lower substrate 300 wet etched, for example, tetramethylammonium hydroxide (TMAH) or KOH can be used as an etchant. When a silicon substrate with a crystal surface in the direction ( 100 ) as the lower substrate 300 is used, the ink induction part 311 having a quadrangular pyramid shape using the anisotropic wet etch characteristics of the faces ( 100 ) and ( 111 ) are formed. That is, an etching rate of the surface ( 111 ) is much lower than the etching rate of the surface ( 100 ) and therefore becomes the lower substrate 300 along the surface ( 111 ), so that the ink induction part 311 is formed with the quadrangular pyramid shape. Accordingly, the bottom of the ink induction part becomes 311 the area ( 100 ).
Thereafter, the photoresist (PR) is applied to the surface of the silicon oxide layer 351b applied to the bottom of the lower substrate 300 is formed, as in 13E shown. Subsequently, the applied photoresist (PR) is developed, whereby an opening 316 for forming an opening of a nozzle on the underside of the lower substrate 300 is formed.
Thereafter, a part of the silicon oxide layer 351b passing through the opening 316 is wet etched using the photoresist (PR) as an etch mask and removed, leaving the underside of the lower substrate 300 is partially exposed. In this case, the silicon oxide layer 351b not by wet etching, but by dry etching, such as RIE.
Thereafter, the exposed part of the lower substrate becomes 300 etched using the PR as an etching mask so that the nozzle passes through the lower substrate 300 can run, whereby one with the ink induction part 311 connected opening 312 is formed. In this case, the etching of the lower substrate 300 be carried out by dry etching with ICP.
Subsequently, after the photoresist (PR) is peeled off, the lower substrate 300 in which a base mark 340 in the area of the edges of the top and bottom of the lower substrate 300 is formed and through the one nozzle 310 formed from the ink induction part 311 and the opening 312 runs, prepared, as in 13H shown. Meanwhile, the opening becomes 312 formed after the ink induction part 311 as described above, but the ink induction part 311 can be made after the opening 312 is trained.
Likewise, those on the top and bottom of the lower substrate 300 formed silicon oxide layers 351a and 351b can be removed in a cleaning process, and then a new Silici umoxidschicht on the entire surface of the lower substrate 300 be formed again.
14 FIG. 12 is a cross-sectional view illustrating a step of sequentially stacking the lower substrate, the intermediate substrate, and the upper substrate, and adhering the substrates to each other.
In reference to 14 become the bottom substrate 300 , the intermediate substrate 200 and the upper substrate 100 that are prepared by the above steps, stacked and sticking to each other. In this case, the intermediate substrate adheres 200 at the lower substrate 300 and then the upper substrate adheres to the intermediate substrate 200 but the order of attachment can be variable. The three substrates 100 . 200 and 300 are aligned using a mask aligner and are alignment base marks 140 . 240 and 340 on each of the three substrates 100 . 200 and 300 provided, and thereby the alignment precision is high. The adhesion of the three substrates 100 . 200 and 30 can by known Si liciumdirectbonding (SDB). Meanwhile, in an SDB process, silicon adheres better to a silicon oxide layer than to another silicon layer. Therefore, the upper substrate is preferred 100 and the lower substrate 300 on which silicon oxide layers 153a . 153b . 351a and 351b are formed, used and the intermediate substrate 200 on which no silicon oxide layer is formed is used as in 14 shown.
The 15A and 15B 15 are cross-sectional views illustrating a step for completing the piezoelectric ink-jet printhead according to the present invention by forming a piezoelectric actuator on the upper substrate.
In reference to 15A become the bottom substrate 300 , the intermediate substrate 200 and the upper substrate 100 stacked in sequence and adhere to each other, and a silicon oxide layer 180 is used as an insulating layer on top of the upper substrate 100 educated. The step of forming the silicon oxide layer 180 can be left out. That is, when the silicon oxide layer 153a already on top of the upper substrate 100 was trained as in 14 shown, or if an oxide layer of a certain thickness already on top of the upper substrate 100 was formed in a heat treatment step of the above SDB process, there is no need to form the in 15A shown silicon oxide layer 180 as an insulating layer on top of the upper substrate 100 ,
Subsequently, lower electrodes 191 and 192 a piezoelectric actuator on the silicon oxide layer 180 educated. The lower electrodes 191 and 192 are formed of two thin metal layers, such as a Ti layer 191 and a Pt layer 192 , The Ti layer 191 and the Pt layer 192 can be achieved by sputtering the entire surface of the silicon oxide layer 180 be formed to a certain thickness. The Ti layer 191 and the Pt layer 192 serve as a common electrode of the piezoelectric actuator and further serve as a diffusion barrier layer, the diffusion between the piezoelectric layer formed thereon ( 193 from 15B ) and the upper substrate formed thereunder 100 prevented. In particular, the lower Ti layer serves 191 for improving the adhesion properties of the Pt layer 192 ,
Thereafter, the piezoelectric layer 193 and the upper electrode 194 on the lower electrodes 191 and 192 formed as in 15B shown. Specifically, a piezoelectric material in pasty state is applied to the pressure chamber 120 applied to a certain thickness by screen printing and then dried ge for a certain period of time. Preferred are lead zirconate titanate (PZT) ceramic materials for the piezoelectric layer 193 used. Subsequently, an electrode material, for example Ag-Pd paste, is applied to the dried piezoelectric layer 193 printed. Thereafter, the piezoelectric layer 193 sintered at a certain temperature, for example at 900 to 1000 ° C. In this case, prevent the Ti layer 191 and the Pt layer 192 a diffusion between the piezoelectric layer 193 and the upper substrate 100 in a high-temperature sintering process of the piezoelectric layer 193 can occur.
Such becomes a piezoelectric actuator 190 composed of the lower electrodes 191 and 192 , the piezoelectric layer 193 and the upper electrode 194 on the upper substrate 100 educated.
Meanwhile, the sintering of the piezoelectric layer becomes 193 under atmospheric conditions, and thereby a silicon oxide layer is formed inside the ink passage made of the three substrates in the sintering step 100 . 200 and 300 is formed. The silicon oxide layer does not react with almost all types of ink and therefore a variety of inks can be used. In addition, the silicon oxide layer has a hydrophilic property, and therefore the inflow of air bubbles is prevented when flowing in first, and the occurrence of air bubbles is suppressed when ink is ejected through the nozzle.
Finally, when a dicing process for cutting the adherent three substrates 100 . 200 and 300 in chip units and a triggering process for generating piezoelectric properties by applying an electric field to the piezoelectric layer 193 to be performed, the piezoelectric ink-jet printhead according to the present invention is completed. Meanwhile, the dicing process may be performed before the above-mentioned sintering step of the piezoelectric layer 193 be performed.
As As described above, the piezoelectric ink-jet printhead and the process for its preparation according to the present invention the following advantages.
First, the ink passage forming members can be precisely and easily formed to a fine size on each of the three substrates formed of monocrystalline silicon using a silicon micromachining technology. In this way, the machining allowance is reduced, thereby minimizing deviation in ink ejection performance that can. In addition, in the present invention, the silicon substrate is used and therefore can be used in a process for manufacturing typical semiconductor devices, and mass production can be easily performed. Therefore, the present invention is suitable for high-density print heads to improve printing resolution.
Secondly, the three substrates are prepared using a mask aligner layered on each other and adhere to each other, creating a precise alignment and high productivity be achieved. This means, the number of adhering substrates is compared to the state technology, which simplifies alignment and adhesion processes and errors in the alignment process are also reduced. Especially, when the base mark is formed on each substrate is the precision further improved in the alignment process.
Third, because the three substrates that make up the print head are made of a monocrystalline Silicon substrate are formed, their adhesion is high. Although there is a variation in ambient temperature during printing, If no deformation or subsequent misalignment occurs, since the thermal expansion coefficient the substrates are the same.
Fourth, since the monocrystalline silicon substrate is used as the base material is, the surface roughness is an etching surface after a dry or wet etching process reduces, which favors the flow of ink.
Fifth, because the silicon oxide layer does not work with almost all types of ink reacts and has a hydrophilic property, in some steps of Manufacturing process formed inside the ink passage a variety of inks can be used and the influx of air bubbles becomes prevents when ink flows in and out the appearance of air bubbles is suppressed when Ink through the nozzle pushed out becomes.
Sixth, as a part of the upper substrate made of silicon with high mechanical Properties formed as vibration plate, take the mechanical properties do not decrease when the upper substrate coupled to the piezoelectric actuator and then the piezoelectric actuator via a operated for a long time.
Seventh, is due to the Ti and Pt layers diffusion between the piezoelectric Layer and the upper substrate, in particular between the piezoelectric Layer and the vibration plate prevents the sintering step the piezoelectric layer may occur, and the piezoelectric Actuator and the vibration plate adhere to each other without intervening lying gap, causing deformation of the piezoelectric layer transferred without delay or displacement damage to the vibration plate can be. In this way, an ink ejection movement done quickly since the vibration plate in operation of the piezoelectric actuator and indirectly. Furthermore For example, the present invention has the above advantages when the piezoelectric actuator is in a radio frequency range is operated.
Eighth, when an ink jet print head has a T-shaped throttle the flow resistance of ink, which is led from the ink reservoir to the pressure chamber, decreases and a pressure drop in the step for feeding Ink is reduced by the throttle. Thus, the flow rate, the the throttle goes through elevated, so that ink is replenished more smoothly and faster in the pressure chamber. In this way, even if the inkjet printhead in one High frequency range is operated, uniform ink ejection volume and ink ejection speed be achieved.
Even though preferred embodiments of the present invention in detail The scope of the present invention is not on these embodiments limited and it can different changes for this purpose and other embodiments are obtained. For example, you can in forming elements of a piezoelectric ink jet printhead according to the present Invention and a series of etching methods be applied in the manufacture of an ink jet print head, and the order of each step of the method of making the piezoelectric inkjet printhead can be changed.
While these Invention in particular with reference to preferred embodiments shown and described, it is understood by those skilled in the art that different changes in shape and details may be made without departing from the scope of the invention as defined by the appended claims.
A piezoelectric ink-jet printhead comprising: an upper substrate ( 100 ) through which an ink supply passage ( 110 ), is supplied through the ink is formed, wherein a pressure chamber ( 120 ) is formed for filling with ejected ink on the underside of the upper substrate; a monolithic on the upper substrate ( 100 ) formed piezoelectric actuator ( 190 ) providing a driving force for ejecting ink to the pressure chamber; an intermediate substrate comprising: an ink reservoir ( 210 ), which is connected to the ink supply passage and accommodated in the supplied ink, a damper ( 230 ) next to one end of the pressure chamber and a throttle ( 220 ) connecting the other end of the pressure chamber to the ink reservoir; and a lower substrate ( 300 ) with a nozzle ( 310 ) through which ink is to be ejected, in communication with the damper; the lower substrate ( 300 ), the intermediate substrate ( 200 ) and the upper substrate ( 100 ) are sequentially stacked and adhere to each other, wherein the three substrates are monocrystalline silicon substrates ( 100 . 200 . 300 ) are; characterized in that the ink reservoir is on top of the intermediate substrate; and the choke is formed on the underside of the upper substrate and / or the upper surface of the intermediate substrate.
A printhead according to claim 1, wherein a portion having an upper wall of the pressure chamber (US Pat. 120 ) of the upper substrate, as a vibration plate ( 103 ), which by controlling the piezoelectric actuator ( 190 ) is deformed.
The printhead of claim 2, wherein the top substrate is formed of a silicon on insulator (SOI) wafer having a structure in which a first silicon substrate (FIG. 101 ), an intermediate oxide layer ( 107 ) and a second silicon substrate ( 102 ) are sequentially stacked on top of each other, and the pressure chamber on the first silicon substrate ( 101 ) and the second silicon substrate ( 103 ) serves as the vibration plate.
Printhead according to one of the preceding claims, wherein the pressure chamber ( 120 ) in two columns on both sides of the ink reservoir ( 210 ) is arranged.
A printhead according to claim 4, wherein for dividing the ink reservoir in a vertical direction, a barrier wall (Fig. 215 ) is formed in the reservoir in a longitudinal direction of the ink reservoir.
Printhead according to one of the preceding claims, wherein a silicon oxide layer ( 180 ) between the upper substrate ( 103 ) and the piezoelectric actuator ( 190 ) is trained.
Printhead according to claim 6, wherein the silicon oxide layer ( 180 ) is arranged so as to suppress material diffusion and thermal stress between the upper substrate and the piezoelectric actuator.
Printhead according to one of the preceding claims, wherein the piezoelectric actuator comprises: a lower electrode ( 191 . 192 ) formed on the upper substrate ( 100 ); a piezoelectric layer ( 193 ) is formed on the lower electrode so as to be placed on an upper part of the pressure chamber; and an upper electrode ( 194 ) formed on the piezoelectric layer and applying a voltage to the piezoelectric layer.
Printhead according to claim 8, wherein the lower electrode ( 191 . 192 ) has a two-layer structure in which a Ti layer ( 191 ) and a Pt layer ( 192 ) are stacked on top of each other.
A printhead according to claim 9, wherein the Ti layer ( 191 ) and the Pt layer ( 192 ) serve as a common electrode of the piezoelectric actuator and further serve as a diffusion barrier layer which prevents interdiffusion between the upper substrate and the piezoelectric layer.
Printhead according to one of the preceding claims, wherein the nozzle ( 310 ) comprises: an opening ( 312 formed in a lower part of the lower substrate; and an ink induction part ( 311 ) formed in an upper part of the lower substrate and connecting the damper to the opening.
A printhead according to claim 11, wherein the cross-sectional area of the ink inducing part (16) 311 ) gradually decreases from the area of the damper to the area of the opening.
A printhead according to claim 12, wherein said ink induction member (16) 311 ) is formed in a quadrangular pyramid shape.
Printhead according to one of the preceding claims, wherein the throttle ( 220 ) has a T-shaped cross-section and is formed from the top of the intermediate substrate deep in a vertical direction.
A method of manufacturing a piezoelectric ink-jet printhead, the method comprising: preparing an upper substrate ( 100 ), an intermediate substrate ( 200 ) and a lower substrate ( 300 ) formed of a monocrystalline silicon substrate; Micromachining the upper substrate ( 100 ), the intermediate substrate ( 200 ) or the lower substrate ( 300 ), so that an ink passage is formed; Laying down the lower substrate ( 100 ), the intermediate substrate ( 200 ) and the upper substrate ( 300 ) in each of which the ink passage has been formed so that the lower substrate, the intermediate substrate and the upper substrate adhere to each other; and forming a piezoelectric actuator ( 190 ) providing a driving force for ejecting ink on the upper substrate; wherein forming the ink passage comprises: forming a pressure chamber (US Pat. 120 ) to be filled with ink to be ejected, and an ink supply passage ( 110 ), through which ink is supplied, on the underside of the upper substrate; Forming a throttle ( 220 ) connected to one end of the pressure chamber, at least on one side of the lower surface of the upper substrate and the upper surface of the intermediate substrate; Forming a damper ( 230 ) connected to the other end of the pressure chamber in the intermediate substrate; Forming an ink reservoir ( 210 one end of which is connected to the ink supply passage, and one side of which is connected to the reactor, on top of the intermediate substrate; and forming a nozzle ( 310 ), which is connected to the damper, in the lower substrate.
The method of claim 15, further comprising, prior to forming the ink passage, forming a base mark ( 240 ) on each of the three substrates so that the three substrates are aligned as the three substrates adhere.
The method of claim 16, wherein in forming the base mark ( 240 ) the vicinity of at least one edge of the underside of the upper substrate and the vicinity of the edges of the upper and lower sides of the intermediate substrate and the lower substrate are etched to a certain thickness, whereby the base mark ( 240 ) is formed.
The method of claim 17, wherein the base marker ( 240 ) is formed by wet etching using a tetramethylammonium hydroxide (TMAH) or KOH as an etchant.
Method according to claim 15, wherein in forming the pressure chamber ( 120 ) and the ink supply passage ( 110 ), the bottom of the upper substrate is dry etched to a certain depth, thereby simultaneously forming the pressure chamber and the ink supply passage.
A method according to claim 19, wherein in forming the pressure chamber ( 120 ) and the ink supply passage ( 110 ) a silicon on insulator (SOI) wafer having a structure in which a first silicon substrate ( 101 ), an intermediate oxide layer ( 102 ) and a second silicon substrate ( 103 ) are stacked sequentially as the upper substrate is used and the first silicon substrate ( 101 ) using the intermediate oxide layer ( 102 ) is etched as an etch stop layer, whereby the pressure chamber and the ink supply passage are formed.
The method of claim 19, wherein after forming the pressure chamber ( 120 ) and the ink supply passage ( 110 ) the entire surface of the upper substrate is purified using a tetramethylammonium hydroxide (TMAH).
The method of claim 19, wherein the ink supply passage ( 110 ) formed on the lower surface of the upper substrate to a certain depth is perforated after forming the piezoelectric actuator.
Method according to one of claims 15 to 22, wherein in forming the throttle ( 220 ), the bottom of the upper substrate is dry etched or wet etched using TMAH or KOH as an etchant, thereby forming the reactor.
Method according to one of claims 15 to 22, wherein in forming the throttle ( 220 ) the top of the intermediate substrate is dry etched or wet etched using TMAH or KOH as an etchant, thereby forming the reactor.
Method according to one of claims 15 to 22, wherein in forming the throttle ( 220 ) the underside of the upper substrate or the upper side of the intermediate substrate are respectively dry-etched or wet-etched using TMAH or KOH as an etchant, whereby a part of the reactor ( 220 ) is formed on the underside of the upper substrate and the other part of the throttle ( 220 ) is formed at the top of the intermediate substrate.
Method according to one of claims 15 to 22, wherein in forming the throttle ( 220 ) the top of the intermediate substrate is etched to a certain depth by dry etching using inductively coupled plasma (ICP), thereby forming the reactor with a T-shaped cross-section.
The method of claim 26, wherein forming the throttle ( 220 ) and the formation of the ink reservoir ( 210 ) at the same time.
Method according to one of claims 15 to 27, wherein the formation of the damper ( 230 ) comprises: forming a depression ( 232 ) having a certain depth connected to the other end of the pressure chamber, on top of the intermediate substrate; and perforating the recess ( 232 ), whereby the damper is formed connected to the other end of the pressure chamber.
The method of claim 28, wherein forming the recess ( 232 ) is carried out by sandblasting and the perforation of the recess ( 232 ) is performed by dry etching using ICP.
The method of claim 29, wherein before sandblasting a dry film Photoresist using a lamination process as a protective layer is applied to another part of the intermediate substrate to protect the intermediate substrate.
The method of claim 28, wherein forming the recess ( 232 ) and perforating the well by dry etching using ICP.
The method of claim 28, wherein perforating the recess ( 232 ) is performed simultaneously with the formation of the ink reservoir.
Method according to one of claims 15 to 32, wherein in forming the ink reservoir ( 210 ) the top of the intermediate sub strate is dry etched to a certain depth, whereby the ink reservoir ( 210 ) is formed.
A method according to claim 33, wherein in forming the ink reservoir ( 210 ) for partitioning the ink reservoir in a vertical direction, a barrier wall ( 215 ) is formed in the ink reservoir in a longitudinal direction of the ink reservoir.
A method according to claim 33 or 34, wherein the ink reservoir ( 210 ) is formed by dry etching using ICP.
The method of any of claims 15 to 35, wherein forming the nozzle ( 310 ): etching the upper surface of the lower substrate to a certain depth to form an ink-inducing part ( 311 ) connected to the damper; and etching the underside of the lower substrate to form an opening ( 312 ) connected to the ink induction part ( 311 ).
A method according to claim 36, wherein in forming the ink-inducing part, the lower substrate is formed by using a silicon substrate having a crystal surface in the direction (FIG. 100 ) is anisotropically wet etched as the lower substrate, whereby the ink induction part ( 311 ) is formed with a quadrangular pyramid shape.
A method according to any of claims 15 to 37, wherein adhering comprises coating the three substrates ( 100 . 200 . 300 ) is performed using a mask aligner.
A method according to any one of claims 15 to 37, wherein adherence of the three substrates ( 100 . 200 . 300 ) using a silicon direct bond (SDB) process.
A method according to claim 39, wherein when adhered to improve a sticking property of the three substrates, the three substrates ( 100 . 200 . 300 ) are bonded together in a state in which silicon oxide films are formed at least on a lower surface of the upper substrate and an upper surface of the lower substrate.
Method according to one of claims 15 to 40, further comprising, prior to forming the piezoelectric actuator ( 190 ), Forming a silicon oxide layer ( 180 ) on the upper substrate.
The method of any one of claims 15 to 41, wherein forming the piezoelectric actuator comprises: sequentially stacking a Ti layer ( 191 ) and a Pt layer ( 192 ) on the upper substrate, so that a lower electrode is formed; Forming a piezoelectric layer ( 193 ) on the lower electrode; and forming an upper electrode ( 194 ) on the piezoelectric layer.
A method according to claim 42, wherein in forming the piezoelectric layer ( 193 ) A piezoelectric material in a pasty state is applied to the lower electrode in a position corresponding to the pressure chamber and then sintered, whereby the piezoelectric layer is formed.
The method of claim 43, wherein applying of the piezoelectric material is carried out by screen printing.
The method of claim 43, wherein during the Sintering the piezoelectric material, an oxide layer on one Inner wall of the ink passage is formed on the three Substrates is formed.
A method according to any one of claims 42 to 45, wherein forming the piezoelectric actuator Ators, after forming the upper electrode, dividing the adhered three substrates into chip units; and applying an electric field to the piezoelectric layer of the piezoelectric actuator so that piezoelectric properties are generated.
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DE60220633D1 DE60220633D1 (en) 2007-07-26
DE60220633T2 true DE60220633T2 (en) 2008-02-21
DE2002620633 Active DE60220633T2 (en) 2001-12-18 2002-12-16 Piezoelectric ink jet printhead and method of making the same
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Owner name: SAMSUNG ELECTRO-MECHANICS CO., LTD., SUWON, GY, KR