JP4403597B2 - Inkjet head manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet head and an ink jet printer, and more particularly to an ink jet head and an ink jet printer that are characterized in that a driving thin film transistor circuit for driving an ink ejection driving source is provided on a substrate by a stacking process. .
[0002]
[Prior art]
Conventionally, as a printer device as an information equipment terminal such as a personal computer, a wire-driven recording head that performs printing by magnetically driving a wire and pressing it against a platen through an ink ribbon and a sheet as a recording medium has been used. Printers and printers using ink jet recording heads that eject ink from nozzles are used, but attention is paid to the fact that ink jet printers that do not generate noise associated with printing are suitable for use in offices. Has been.
[0003]
As such an ink jet printer device, the ink is instantaneously heated and vaporized by a heating element to generate bubbles, and the ink is ejected from the nozzle by the pressure, and the ink is transformed using a piezoelectric element. There is a piezo method in which the deformation force causes the nozzle to fly, and these printers use a silicon semiconductor as an electronic circuit that drives a heating element or a piezoelectric element that ejects ink particles, that is, a driver.
[0004]
Conventionally, in the case of the piezo method, a driver is connected to the print head as a separate component by a cable or mounted on the print head.
In the bubble jet system, an electronic circuit serving as a driver is formed on a silicon substrate, the silicon substrate on which the driver is formed is used as a substrate for a print head, and a heating element, a nozzle, and the like are formed thereon.
[0005]
Such a conventional ink jet type recording head includes an ink ejection drive source such as a nozzle, an ink flow path, an ink supply system, an ink tank, a heating element or a piezoelectric element, etc., and generates heat or displacement generated by the ink ejection drive source. By transmitting pressure to the ink flow path, ink particles are ejected from the nozzles, and characters and images are recorded on a recording medium such as paper.
[0006]
[Problems to be solved by the invention]
However, the method in which the driver is a separate component has mounting problems such as a long wiring or difficult wiring, and the overall complexity becomes high and the cost becomes high. There is a problem that it is difficult to realize.
[0007]
In addition, the method of forming the driver on the silicon substrate has a silicon wafer with a maximum size of 15 inches (≈38 cm) and is circular, so that the production efficiency is poor for a line head that requires a certain length. At present, the A4 size is the length limit.
[0008]
Accordingly, an object of the present invention is to provide a driver-integrated ink jet head with no limitation on the head size.
[0009]
[Means for Solving the Problems]
FIG. 1 is an explanatory diagram of the principle configuration of the present invention. Means for solving the problems in the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional perspective view of the main part of a bubble jet type line head.
The present invention provides a method of producing an ink jet head, one rectangular substrate into a plurality of ink ejection nozzles, a plurality of individual ink flow paths corresponding to the plurality of ink ejection nozzles, the plurality of individual ink channels Patterning a plurality of corresponding ink supply paths, and a shape serving as a common ink chamber for supplying ink to each of the plurality of individual ink flow paths via the ink supply paths; and the plurality of individual inks A step of embedding a sacrificial layer in a shape to be a flow path, the plurality of ink supply paths, and a common ink chamber, a step of forming a diaphragm on the substrate in which the sacrificial layer is embedded, and a piezoelectric film on the diaphragm after forming, said is patterned in a shape corresponding to the individual ink channels, form a plurality of piezoelectric actuators corresponding to each of the plurality of individual ink channels A step of, in the next step of forming the piezoelectric actuator, forming a metal film serving as the upper electrode on the piezoelectric actuator, the next step of forming the metal film, formed on the vibration plate forming a thin film transistor circuit by the membrane, a step of forming a protective film on the substrate after the upper electrode is deposited, the substrate after the protective film is formed, the upper electrode and Forming a wiring connected to the thin film transistor circuit, forming a wiring layer to be a wiring connected to the upper electrode of the piezoelectric actuator, patterning the wiring layer into a predetermined pattern, and a remaining sacrificial layer And the step of forming the thin film transistor circuit includes: forming a drive circuit for driving the piezoelectric actuator; and Characterized in that it comprises a step of forming a drive nozzle selection circuit for selecting any one from among a plurality of piezoelectric actuators corresponding to the ink ejection nozzle. Further, in the method of manufacturing an ink jet head according to one aspect of the present invention, the step of forming the wiring connected to the upper electrode is performed after forming a via that is electrically connected to the wiring layer so as to penetrate the protective film. The method includes a step of forming a wiring for a piezoelectric actuator that conducts the via and the upper electrode of the piezoelectric actuator. The embodiment in which the substrate is a photosensitive glass substrate is preferable. It is also preferable that the method includes a step of connecting the ink introduction connection port and the wiring member to form a head segment after cutting the substrate into individual heads. Furthermore, it is preferable that the head segment includes a step of aligning and adhering the head segments so that the ink ejection nozzles are sequentially shifted to form an integrated inkjet head.
[0010]
Thus, by providing the thin film transistor circuit 5 formed by the stacking process on the substrate 1 on which the plurality of ink ejection nozzles 2, the individual ink flow paths connected to the ink ejection nozzles 2, and the ink ejection drive source 4 are arranged. The thin film transistor circuit 5 serving as a driver can be formed integrally with the substrate 1 instead of being a separate component, thereby reducing the cost and increasing the nozzle density. Further, since the thin film transistor circuit 5 is used as a driver, the substrate 1 does not need to be a single crystal silicon substrate, and the use of the square substrate 1 such as glass eliminates the limitation on the head size and improves the manufacturing efficiency. To do. Further, by forming the thin film transistor circuit 5 from non-single crystal silicon such as amorphous silicon, polycrystalline silicon, or microcrystalline silicon instead of single crystal silicon, integration with a substrate such as glass becomes possible.
[0011]
Before SL ink ejection driving source, aspects either resistance heating source or a piezoelectric actuator is preferred.
[0012]
As described above, the driver integrated head in which the thin film transistor circuit 5 is integrated includes a bubble jet ink jet head using a resistance heating source as the ink ejection drive source 4 and a piezo ink jet head using a piezoelectric actuator as the ink ejection drive source 4. Applies to
[0013]
(3) Further, the present invention is characterized in that, in the above (1) or (2), the thin film transistor circuit 5 includes at least one of a drive circuit for driving the ink ejection drive source 4 and a drive nozzle selection circuit. To do.
[0014]
As described above, the thin film transistor circuit 5 integrated with the substrate 1 only needs to include at least one of the drive circuit for driving the ink ejection drive source 4 and the drive nozzle selection circuit.
[0015]
Before SL substrate, embodiments comprising at least one of single-crystal silicon substrate and the glass substrate is preferred.
[0016]
As described above, since the thin film transistor circuit or the like is configured by using the semiconductor manufacturing process, the mounting process or wiring process of another component is not required, the manufacturing process is simplified, and the nozzle density can be increased. Become.
[0017]
(5) Further, the present invention is characterized in that an inkjet head according to any one of (1) to (4) is mounted in an inkjet printer.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Here, with reference to FIG.2 and FIG.3, the manufacturing process of the bubble jet type line head of the 1st Embodiment of this invention is demonstrated.
The specifications of the bubble jet type line head are a printing width of 200 mm, a nozzle pitch of 2,400 dpi (1,200 dpi × 2 rows / color), and an ink flow rate of 2 pl.
2A. First, a TFT circuit 20 is formed on a square soda glass substrate 11 having a size of 250 × 250 × 2 mm by the same method as the TFT driving liquid crystal display device.
[0019]
Reference to FIG. 2B FIG. 2B is an enlarged cross-sectional view of the TFT circuit 20 in FIG. 2A. For example, a base SiO ₂ film 12 having a thickness of 300 nm is formed by PCVD (plasma CVD). After the deposition, a Ta film having a thickness of 150 nm is deposited by sputtering, and patterned into a predetermined shape to form the Ta gate electrode 13 and the gate bus line. Then, using the PCVD method, for example, the thickness is increased. A SiN gate insulating film 14 is formed by depositing a SiN film having a thickness of 400 nm.
[0020]
Next, for example, an undoped α-Si film 15 having a thickness of 15 nm and a SiN film having a thickness of 120 nm are sequentially deposited using the PCVD method, and then self-aligned exposure is performed using the Ta gate electrode 13 as a mask. As a result, the channel protective film 16 is formed by patterning the SiN film into a predetermined shape, and the n ⁺ -type α-Si film 17 having a thickness of 30 nm, for example, is deposited again by using the PCVD method, and then the reactivity. By performing ion etching, the n ⁺ -type α-Si film 17 and the α-Si film 15 are patterned so as to form one TFT.
[0021]
Next, a Ta film having a thickness of, for example, 150 nm is deposited on the entire surface by sputtering, and then patterned including the n ⁺ type α-Si film 17 to form the source / drain electrodes 18, thereby forming the TFT circuit 20. Finally, the SiON protective film 21 is provided on the entire surface of the soda glass substrate 11.
[0022]
Next, referring to FIG. 2C, for example, after depositing a durable TiN film having a thickness of 200 nm, the TiN heat generating layer pattern 22 is formed by patterning so as to correspond to individual ink flow paths. .
Next, after forming a via hole reaching the TFT circuit 20 in the SiON protective film 21, an Al film is deposited on the entire surface and patterned to form an Al heater wiring layer 23 and an Al wiring layer 24, and then again on the entire surface. For example, the SiON protective film 25 having a thickness of 500 nm is provided.
[0023]
Next, after depositing SOG (spin-on-glass) 26 on the entire surface, patterning is performed so that the remaining portion forms an ink flow path 27, an ink supply path 28, and a common ink chamber 29. The ink flow path wall 30 is formed by plating hard Cr that does not react with the ink.
[0024]
Reference to FIG. 3E FIG. 3E is a cross-sectional perspective view of an essential part. After the nozzles 31 are formed by irradiating an excimer laser, the remaining SOG 26 is removed by etching through the nozzles 31 and the like. .
Although not shown in the drawings, the soda glass substrate is cut into individual heads, and then the ink introduction connection port and the flexible cable are connected to form a head segment.
By attaching such a head segment to a printer apparatus having a paper feed mechanism, an ink tank, and a head cleaning / purge mechanism, a bubble jet type ink jet printer is completed.
[0025]
As described above, in the first embodiment of the present invention, since the rectangular soda glass substrate 11 is used as the substrate, an arbitrary size substrate can be used, and the head size is not limited. A driver integrated head can be manufactured efficiently.
[0026]
In the present invention, since the ink flow path wall 30 made of Cr is formed by using a semiconductor technique of SOG application and patterning, work and alignment such as mounting of the ink flow path wall member is not necessary, and Since the Al heater wiring layer 23 for driving the TiN heat generating layer pattern 22 is also formed by using semiconductor technology, work such as connection with a flexible cable becomes unnecessary, and thus the manufacturing process is simplified, and Higher nozzle density is possible.
[0027]
In the above description of the first embodiment, a TiN film is used as the heat generation layer. However, an SiC film may be used instead of the TiN film, and the ink flow path wall 30 is provided. Ni may be used instead of Cr, which is formed of Cr.
[0028]
Next, with reference to FIGS. 4 and 5, the manufacturing process of the piezo type line head according to the second embodiment of the invention will be described.
The specifications of the bubble jet type line head include a printing width of 300 mm (A3 compatible), a nozzle pitch of 2,400 dpi (600 dpi × 4 columns / color), and an ink flow rate of 2 pl.
4A. First, exposure is performed on a pattern that forms a nozzle 42, an ink flow path 43, an ink supply path 44, and a common ink chamber 45 on a square photosensitive glass substrate 41 of 350 × 350 × 2 mm. Then, the exposed portion is crystallized and the crystallized region is removed by etching, thereby forming the nozzle 42, the ink flow path 43, the ink supply path 44, and the common ink chamber 45.
In order to form each region at a different depth, the exposure amount may be adjusted.
[0029]
Next, referring to FIG. 4B, after the nozzle 42, the ink flow path 43, the ink supply path 44, and the common ink chamber 45 formed on the photosensitive glass substrate 41 by dip coating are filled with the SOG 46, CMP (Chemical Mechanical Polishing) is performed. ) Method to flatten the surface.
Next, a TiN vibration plate 47 is formed by depositing a hard TiN film having a thickness of 0.1 to 10 μm, for example, 1.0 μm on the planarized SOG 46 by using a sputtering method.
[0030]
Next, referring to FIG. 4C, a PZT (PbZr _x Ti _1-x O ₃ ) film having a thickness of 0.2 to 20 μm, for example, 1.0 μm is deposited on the entire surface by ECR sputtering. A PZT piezoelectric layer 48 is formed by patterning into a shape corresponding to the ink flow path 43, and then a Pt upper electrode 49 having a thickness of, for example, 100 nm is formed by a mask sputtering method using a mask.
[0031]
Next, a TFT circuit 50 is formed on the TiN diaphragm 47 by a method similar to the forming method shown in FIG.
That is, for example, a base SiO ₂ film having a thickness of 100 nm is deposited on the TiN diaphragm 47 by a PCVD method, and then a Ta film having a thickness of 150 nm is deposited by a sputtering method and patterned into a predetermined shape. Then, a Ta gate electrode and a gate bus line are formed, and then a SiN gate insulating film is formed by depositing, for example, a SiN film having a thickness of 400 nm using the PCVD method.
Next, for example, by sequentially depositing an undoped α-Si film having a thickness of 15 nm and a SiN film having a thickness of 120 nm by using the PCVD method, self-aligned exposure using the Ta gate electrode as a mask is performed. A channel protection film is formed by patterning the SiN film into a predetermined shape, and again, for example, an n ⁺ -type α-Si film 17 having a thickness of 30 nm is deposited by PCVD, and then reactive ion etching is performed. By applying, the n ⁺ type α-Si film and the α-Si film are patterned so as to form one TFT.
Next, for example, a Ta film having a thickness of 150 nm is deposited on the entire surface by sputtering, and then patterned including the n ⁺ -type α-Si film to form source / drain electrodes, thereby forming the TFT circuit 50. To do.
[0032]
Next, for example, a 100 nm thick SiON protective film 51 is provided on the entire surface, via holes reaching the Pt upper electrode 49 and the TFT circuit 50 are formed, and then an Al film is deposited on the entire surface and patterned to form an Al wiring layer 52. Then, an Al wiring layer 53 is formed, and then a 100 nm SiON protective film 54 having a thickness of, for example, is again provided on the entire surface.
[0033]
FIG. 5E is a cross-sectional perspective view of the main part, and the remaining SOG 46 is removed by etching through the nozzle 42 and the like.
Although not shown in the drawings, after the photosensitive glass substrate 41 is cut into individual heads, an ink introduction connection port and a flexible cable are connected to form a head segment.
Four such head segments for each color of magenta, yellow, and cyan are aligned so that the positions of the nozzles 42 are sequentially shifted, bonded, and integrated to form a color print head. A piezo ink jet printer is completed by attaching to a printer device having a paper feed mechanism, an ink tank, and a head cleaning / purge mechanism.
[0034]
As described above, in the second embodiment of the present invention, since the rectangular photosensitive glass substrate 41 is used as the substrate, an arbitrary size substrate can be used, and the head size is limited. It is possible to efficiently manufacture a head with no driver.
[0035]
In the present invention, the ink flow path, the diaphragm, the piezoelectric actuator, and the TFT circuit are configured on the photosensitive glass substrate 41 using a semiconductor manufacturing process such as a deposition process and an etching process. A process or a wiring process becomes unnecessary, the manufacturing process is simplified, and a high nozzle density can be achieved.
[0036]
As mentioned above, although each embodiment of the present invention has been described, the present invention is not limited to the configuration in each embodiment, and various modifications are possible.
For example, in the first embodiment, a soda glass substrate is used as the substrate. However, the substrate is not limited to the soda glass substrate, and has a heat resistance and strength equal to or higher than that of soda glass. For example, quartz glass or Pyrex glass may be used.
[0037]
In addition, when a square and large-diameter single crystal silicon substrate is manufactured at low cost, a single crystal silicon substrate may be used as the substrate, and in particular, the second embodiment described above. As in the embodiment, this is suitable when an ink flow path or the like is formed on the substrate by etching.
[0038]
In each of the above embodiments, the TFT circuit is formed of α-Si. However, the TFT circuit is not limited to α-Si, and polycrystalline silicon or microcrystalline silicon may be used. In addition, the shape of each TFT is not limited to the structure in which the gate electrode is provided on the substrate side. A non-single-crystal silicon layer is deposited on the substrate, and the gate electrode is formed thereon with a gate insulating film interposed therebetween. A TFT having a structure may be used.
[0039]
In each of the above embodiments, the heat generation layer or the piezoelectric layer is deposited on the entire surface and then patterned. However, it may be selectively formed from the beginning using a lift-off method, a mask sputtering method, or the like. Is.
[0040]
In the second embodiment, PZT to be a piezoelectric layer is deposited by ECR sputtering. However, it may be deposited by MOCVD, and the piezoelectric material is PZT. The perovskite oxide containing Pb similar to PZT may be used.
[0041]
In the second embodiment described above, since the conductive TiN is used as the diaphragm, the lower electrode is omitted. However, the diaphragm may be an insulator and is made of an insulator. In this case, it is necessary to form the lower electrode before depositing the piezoelectric layer.
[0042]
Further, the present invention is premised on a line printer that fixes or slightly moves the head, but is not necessarily limited to the line printer, and is also applied to an inkjet printer that performs printing while being mounted on a shuttle and driven. Is.
[0043]
【The invention's effect】
According to the present invention, a rectangular and large-area inexpensive substrate is used as the substrate, and the driver for driving the ink ejection drive source is formed by the thin film transistor. Therefore, the driver can be integrated, and the inkjet line printer Therefore, it is possible to reduce the size and weight of the ink jet printer, which greatly contributes to the miniaturization and speeding up of the ink jet printer.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a basic configuration of the present invention.
FIG. 2 is an explanatory diagram of a manufacturing process up to the middle of the bubble type line head according to the first embodiment of this invention;
FIG. 3 is an explanatory diagram of the manufacturing process subsequent to FIG. 2 for the bubble type line head according to the first embodiment of the invention;
FIG. 4 is an explanatory diagram of a manufacturing process up to the middle of a piezo type line head according to a second embodiment of the invention;
FIG. 5 is an explanatory diagram of the manufacturing process after FIG. 4 of the piezo type line head according to the second embodiment of the invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Substrate 2 Ink ejection nozzle 3 Individual ink flow path 4 Ink ejection drive source 5 Thin film transistor circuit 11 Soda glass substrate 12 Base SiO ₂ film 13 Ta gate electrode 14 SiN gate insulating film 15 α-Si film 16 Channel protective film 17 n ⁺ Type α-Si film 18 Source / drain electrode 20 TFT circuit 21 SiON protective film 22 TiN heating layer pattern 23 Al heater wiring layer 24 Al wiring layer 25 SiON protective film 26 SOG
27 Ink channel 28 Ink supply channel 29 Common ink chamber 30 Ink channel wall 31 Nozzle 41 Photosensitive glass substrate 42 Nozzle 43 Ink channel 44 Ink supply channel 45 Common ink chamber 46 SOG
47 TiN diaphragm 48 PZT piezoelectric layer 49 Pt upper electrode 50 TFT circuit 51 SiON protective film 52 Al wiring layer 53 Al wiring layer 54 SiON protective film

Claims (5)

A plurality of ink ejection nozzles on one rectangular substrate, a plurality of individual ink flow paths corresponding to the plurality of ink ejection nozzles, a plurality of ink supply paths corresponding to the plurality of individual ink flow paths, and the ink Patterning a shape to be a common ink chamber for supplying ink to each of the plurality of individual ink flow paths via a supply path ;
Embedding a sacrificial layer in a shape that forms the plurality of individual ink channels, the plurality of ink supply channels, and a common ink chamber;
Forming a diaphragm on the substrate with the sacrificial layer embedded therein;
Forming a plurality of piezoelectric actuators corresponding to each of the plurality of individual ink flow paths by forming a piezoelectric film on the diaphragm and then patterning the piezoelectric film into a shape corresponding to the individual ink flow paths ;
Next to the step of forming the piezoelectric actuator, a step of forming a metal film to be an upper electrode on the piezoelectric actuator;
Next to the step of forming the metal film, a step of forming a thin film transistor circuit on the diaphragm by film formation;
Forming a protective film on the substrate after the upper electrode is formed;
Forming a wiring connected to the upper electrode and the thin film transistor circuit on the substrate after the protective film is formed, and forming a wiring layer serving as a wiring connected to the upper electrode of the piezoelectric actuator; Patterning the wiring layer into a predetermined pattern;
Removing the remaining sacrificial layer;
Including
The step of forming the thin film transistor circuit includes a step of forming a drive circuit for driving the piezoelectric actuator, and a drive nozzle selection circuit for selecting one of a plurality of piezoelectric actuators corresponding to the plurality of ink ejection nozzles. A method for manufacturing an ink jet head, comprising the step of forming The step of forming the wiring connected to the upper electrode includes forming a via that is electrically connected to the wiring layer so as to penetrate the protective film, and then electrically connecting the via to the upper electrode of the piezoelectric actuator. method of manufacturing an ink jet head according to claim 1, characterized in that it comprises a step of forming a. The substrate manufacturing method according to claim 1 or 2 inkjet head, wherein the a photosensitive glass substrate. The inkjet head according to any one of claims 1 to 3 , further comprising a step of connecting the ink introduction connection port and the wiring member to form a head segment after cutting the substrate into individual heads. Production method. 5. The method of manufacturing an ink jet head according to claim 4 , further comprising a step of aligning and adhering the head segments so that the ink ejection nozzles are sequentially displaced to form an integrated ink jet head.

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