JP2006218735A - Inkjet recording head and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for an inkjet recording head wherein the generation of working waste is prevented even when an inorganic material is used as a constituting material, an apparatus used in a normal semiconductor process can be used, and wafer batch processing is possible to suit mass production. <P>SOLUTION: In a method of forming ink passages and ink delivering openings, an ink passage pattern layer composed of a silicon-based compound, an ink delivering opening pattern layer composed of a metal material, and a nozzle material layer are formed on a substrate where ink delivering pressure generating elements for delivering ink are set. After a part of the ink delivering opening pattern layer which becomes an ink delivering opening open end is exposed to a surface, the ink passage pattern layer and the ink delivering opening pattern layer are removed by wet etching. The inkjet recording head is manufactured by the method. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet recording head that is a liquid discharge head that performs recording by ejecting liquid to form flying droplets.

  The present invention also relates to a printer that performs recording on a recording medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, a facsimile machine having a communication system, and a word processor having a printer unit. And an inkjet recording head applicable to an industrial recording apparatus combined with various processing apparatuses.

  Note that “recording” in the present invention means not only giving an image having a meaning such as a character or a figure to a recording medium but also giving an image having no meaning such as a pattern.

  The inkjet printing method, in which ink droplets are generated and attached to a print medium such as paper, is extremely low in noise during printing and can be printed at a high speed. Since it can be reduced in size, it is a printing method that is easy to make color and compact. As one of the ink jet printing methods, there is a type in which ink is foamed by a heating element and ink is ejected by utilizing the growth of the bubbles.

  In recent years, with the advancement of recording technology, higher density and higher accuracy recording is also required for the inkjet recording technology. Until recently, a photosensitive resin material has been widely used as a main constituent material of an ink discharge mechanism of an ink jet recording head. However, as the nozzle processing density increases from 1200 dpi to 2400 dpi and from 2400 dpi to 4800 dpi, it is difficult to form an ink discharge mechanism of an ink jet recording head using a photosensitive resin material.

  For this reason, by using an inorganic material as its main constituent material, it is hard and not easily scratched, the ink discharge surface is not deteriorated, the joint surface due to internal stress does not break, and is highly durable and highly resistant. A method for manufacturing an ink jet recording head having reliability is proposed in Patent Document 1. In this manufacturing method, an inorganic layer for forming a pattern layer corresponding to the shape of an ink flow path in a thick film laminating step on a member including an ink discharge pressure generating element and forming an ink discharge surface on the pattern layer. After overcoating the material layer, a pattern image of a predetermined ink discharge port shape is irradiated by a femtosecond laser, and the thickness of the pattern layer corresponding to the shape of the ink flow path from the inorganic material layer on the ink discharge side to the ink discharge port It is a method of sublimation ablation processing almost at the same time until it reaches the inside of.

FIG. 4 shows a manufacturing flow of the ink jet recording head. First, as shown in FIG. 4A, after the thermal oxide film 3 is formed on the back surface of the substrate 1 and the ink discharge pressure generating element 2 for discharging ink is formed on the surface of the substrate 1, FIG. 4), a pattern layer 12 corresponding to the shape of the ink flow path is formed on the ink discharge pressure generating element surface 2, and the ink discharge surface is formed on the pattern layer 12 as shown in FIG. The inorganic material layer 13 for forming is laminated. Next, the inorganic material layer is flattened by CMP as shown in FIG. 4- (d). Next, as shown in FIG. 4- (e), a pattern of a predetermined ink discharge port shape is formed by a femtosecond laser. An ink discharge port 9 is formed by irradiating an image. Thereafter, the ink supply port 10 is formed and the pattern layer 12 is removed, whereby an ink jet recording head as shown in FIG.
JP 2001-287373 A

However, in the said patent document 1, there exists a problem as shown to the following (i)-(iii).
(I) Since the femtosecond laser processing range is narrow, the processing time required for one wafer is long and is not suitable for mass production.
(Ii) Since processing waste is generated during laser processing, a step of removing the processing waste is required.
(Iii) It is necessary to purchase a device that is not used in a normal semiconductor process.

  Therefore, the present invention solves the above-described conventional problems, and even when an inorganic material is used as a constituent material, generation of processing scraps is prevented, an apparatus normally used in a semiconductor process can be used, wafer batch processing is possible, and a large amount of processing is possible. An object of the present invention is to provide a method of manufacturing an ink jet recording head suitable for production.

  In order to achieve the above object, the present invention provides an ink jet recording head manufacturing method configured as follows, and an ink jet recording head manufactured by the method.

(A) forming a first layer made of a silicon-based compound on a substrate provided with an ink discharge pressure generating element for discharging ink;
(B) patterning the first layer to form an ink flow path pattern layer;
(C) forming a second layer made of a metal material on the ink flow path pattern layer;
(D) patterning the second layer to form an ink discharge port pattern layer;
(E) forming a nozzle material layer at a position covering the ink flow path pattern layer and the ink discharge port pattern layer on the substrate;
(F) flattening the surface of the nozzle material layer to expose a part of the ink discharge port pattern layer serving as an ink discharge port opening end on the surface;
(G) removing the ink flow path pattern layer and the ink discharge port pattern layer by wet etching to form an ink flow path and an ink discharge port;
An ink jet recording head manufacturing method comprising:

  An ink jet recording head manufactured by the method described above, wherein the ink discharge port communicates with the ink discharge port on a substrate provided with a plurality of ink discharge pressure generating elements for discharging ink, and the ink An ink flow path capable of introducing the ink at a position where the discharge pressure generating element can act, and the ink flow path and the ink discharge port are formed by a nozzle material layer bonded to the substrate. An ink jet recording head.

  As described above, according to the present invention, even when an inorganic material is used as a constituent material, generation of processing waste can be prevented, an apparatus normally used in a semiconductor process can be used, wafer batch processing is possible, and a large amount An ink jet recording head manufacturing method suitable for production can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 3 is a schematic diagram of an ink jet recording head manufactured in the present embodiment. The ink jet recording head (liquid discharge head) has a silicon substrate 1 on which ink discharge pressure generating elements (liquid discharge pressure generating elements) 2 are formed in two rows at a predetermined pitch. In the silicon substrate 1, an ink supply port (liquid supply port) 10 formed by anisotropic etching of silicon using the thermal oxide film 3 as a mask is opened between two rows of the ink discharge pressure generating elements 2. Yes. On the silicon substrate 1, an ink discharge port (liquid discharge port) 9 that opens above each ink discharge pressure generating element 2 and a common ink supply port 10 communicate with each ink discharge port 9 by a silicon oxide film 7. An ink flow path (liquid flow path) is formed. The silicon oxide film 7 may be a silicon nitride film 8.

  This ink jet recording head is disposed so that the surface on which the ink supply port 10 is formed faces the recording surface of the recording medium. The ink jet recording head applies an ink liquid from the ink discharge port 9 by applying a pressure generated by the ink discharge pressure generating element 2 to the ink (liquid) filled in the ink flow path via the ink supply port 10. Recording is performed by discharging droplets and attaching them to a recording medium.

In the present invention, such an ink jet recording head is manufactured by the following method. That is,
(A) forming a first layer made of a silicon-based compound on a substrate provided with an ink discharge pressure generating element for discharging ink;
(B) patterning the first layer to form an ink flow path pattern layer;
(C) forming a second layer made of a metal material on the ink flow path pattern layer;
(D) patterning the second layer to form an ink discharge port pattern layer;
(E) forming a nozzle material layer at a position covering the ink flow path pattern layer and the ink discharge port pattern layer on the substrate;
(F) flattening the surface of the nozzle material layer to expose a part of the ink discharge port pattern layer serving as an ink discharge port opening end on the surface;
(G) removing the ink flow path pattern layer and the ink discharge port pattern layer by wet etching to form an ink flow path and an ink discharge port;
A method for manufacturing an ink jet recording head having

  In the present invention, for example, a substrate made of glass, ceramics, plastic, metal, or the like can be used as the substrate. Such a substrate is not particularly limited to its shape, material, etc. as long as it functions as a part of a member forming the ink flow path and can function as a support for a nozzle material layer described later. It can be used without.

  An ink discharge pressure generating element for discharging ink is provided on the substrate. Although the number of ink discharge pressure generating elements may be one, usually a plurality of ink discharge pressure generating elements are provided. As the ink discharge pressure generating element, an electrothermal conversion element, a piezoelectric element or the like can be used. By such an ink discharge pressure generating element, discharge energy for discharging a recording droplet is given to the ink liquid, and recording is performed. For example, when an electrothermal conversion element is used, the element heats a nearby recording liquid, thereby causing a state change in the recording liquid and generating ejection energy. For example, when a piezoelectric element is used, ejection energy is generated by mechanical vibration of the element. As the ink discharge pressure generating element, an electrothermal conversion element is preferable.

  The ink discharge pressure generating element is connected to a control signal input electrode for operating the element. Various functional layers such as a protective layer may be provided for the purpose of improving the durability of the ink discharge pressure generating element.

  In the present invention, a first layer made of a silicon compound is formed on the substrate as described above (step (a)). This first layer is a layer that will later become a mold for the ink flow path, and is preferably a material that can be dissolved in a strong alkaline solution. For example, polysilicon usually used in a semiconductor process can be used.

  The first layer can be formed to a predetermined thickness according to the amount of ink discharged by vapor deposition, CVD, sputtering, or the like.

  Then, the first layer is patterned to form an ink flow path pattern layer that becomes a mold material of the ink flow path (step (b)). Patterning can be performed by appropriately selecting from methods capable of forming a desired pattern. For example, a positive resist can be applied on the first layer, patterned by photolithography, and then etched.

  In the present invention, a second layer made of a metal material is formed on the ink flow path pattern layer formed as described above (step (c)). This second layer is a layer that will later become a mold for the ink discharge port, and is preferably a material that can be dissolved in a strong alkaline solution. For example, any of Al, Al—Cu, Al—Si, and Al—Si—Cu is preferably used.

  The second layer can be formed to a predetermined thickness according to the amount of ink discharged by vapor deposition, CVD, sputtering, or the like.

  Then, the second layer is patterned to form an ink discharge port pattern layer that serves as a mold material for the ink discharge ports (step (d)). Patterning can be performed by appropriately selecting from methods capable of forming a desired pattern. For example, a positive resist can be applied on the second layer, patterned by photolithography, and then etched.

  As an etching method, for example, an ink discharge port pattern layer having a tapered shape can be obtained by combining a wet etching process and a dry etching process. By using a tapered ink discharge port, the meniscus holding force is improved, and good printing can be obtained when recording on a recording medium.

  Furthermore, an ink discharge port pattern layer having a different shape in the thickness direction can be formed by performing the etching process with different conditions a plurality of times. For example, it is possible to form an ink discharge port pattern layer having a tapered shape in the lower part and a straight tubular shape in which the upper part does not have a tapered shape.

  In the present invention, a nozzle material layer is formed at a position covering the ink flow path pattern layer and the ink discharge port pattern layer on the substrate formed as described above (step (e)). The nozzle material layer is a material resistant to a strong alkaline solution, and is preferably formed of, for example, a silicon oxide film or a silicon nitride film.

  The nozzle material layer can be formed to a predetermined thickness by vapor deposition, CVD, sputtering, or the like. The thickness of the nozzle material layer needs to be a thickness that sufficiently covers the upper surface of the ink discharge port pattern layer.

  At this time, the surface of the nozzle material layer becomes uneven. Further, the ink discharge port pattern layer is completely covered with the nozzle material layer. Therefore, in the present invention, the surface of the nozzle material layer is flattened, and a process of exposing a part of the ink discharge port pattern layer serving as the ink discharge port opening end to the surface is performed (step (f)). This process can be performed by, for example, CMP.

  The method for producing an ink jet recording head of the present invention may further include (h) a step of performing a water repellent treatment on the surface of the nozzle material layer. Examples of the water repellent treatment include a method of coating a Teflon (registered trademark) film as the water repellent layer.

  In the present invention, the ink flow path pattern layer and the ink discharge port pattern layer are removed by wet etching to form the ink flow path and the ink discharge port (step (g)). As the etching solution, for example, tetramethyl hydroxide (TMAH), NaOH, KOH, or the like can be used.

  Also, by providing an ink supply port forming mask having an ink supply port pattern on the back surface of the substrate, an ink supply port communicating with the ink flow path can be formed by wet etching in the step (g). The ink supply port forming mask can be formed of, for example, a thermal oxide film.

  By the above-described method, on the substrate provided with the ink discharge pressure generating element for discharging ink, the ink discharge port, the position communicating with the ink discharge port and the ink discharge pressure generating element can act. An ink jet recording head having an ink flow path capable of introducing the ink and having the ink flow path and the ink discharge port formed by a nozzle material layer bonded to the substrate can be obtained.

  According to the method for producing an inkjet recording head of the present invention, even when an inorganic material is used as a constituent material, generation of processing waste can be prevented, and an apparatus normally used in a semiconductor process can be used. Furthermore, wafer batch processing can be performed. Therefore, it is possible to produce a reliable inkjet recording head in large quantities at a low cost.

  Examples of the ink jet recording head manufacturing method of the present invention will be specifically described below.

Example 1
FIG. 1 shows a manufacturing flow of an ink discharge mechanism portion in the ink jet recording head of Embodiment 1 of the present invention, and an outline thereof will be described. FIG. 1 is a cross-sectional view taken along the line AA ′ of FIG.

  First, as shown in FIG. 1- (a), on a silicon substrate 1 (thickness: 625 μm) having a crystal orientation of (100) plane on which a thermal oxide film 3 is formed in a desired pattern on the back surface. The ink discharge pressure generating element 2 was formed by patterning.

  Next, as shown in FIG. 1- (b), a polysilicon layer 4 is formed on the surface of the silicon substrate 1 where the ink discharge pressure generating element 2 is present as a first layer made of a silicon-based compound by CVD with a predetermined thickness. (14 μm). Further, a positive resist 5 was applied on the polysilicon layer 4 and patterned by photolithography. Note that OFPR800 (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) was used as a positive resist. Thereafter, as shown in FIG. 1- (c), an ink flow path pattern layer was formed by a dry etching process, and the positive resist 5 was removed.

  Next, as shown in FIG. 1- (d), an aluminum layer 6 is formed as a second layer made of a metal material so as to include a polysilicon layer 4 that is an ink flow path pattern layer obtained by patterning. A predetermined thickness (thickness from the upper surface of the polysilicon layer: 11 μm) was deposited by a sputtering method. Further, a positive resist 5 was applied on the aluminum layer 6 and patterned by photolithography. Thereafter, as shown in FIG. 1- (e), the ink discharge port pattern layer having a tapered shape was formed by combining the wet etching process and the dry etching process, and the positive resist 5 was removed.

  Subsequently, as shown in FIG. 1- (f), the nozzle is formed so as to include the polysilicon layer 4 that is the ink flow path pattern layer and the aluminum layer 6 that is the ink discharge port pattern layer obtained by patterning. As a material layer, a silicon oxide film 7 was deposited by CVD to a predetermined thickness (thickness from the upper surface of the aluminum layer: 5 μm, overall 30 μm). At this time, since the surface becomes uneven, as shown in FIG. 1- (g), the surface is polished and flattened by about 5 μm by CMP, and a part of the ink discharge port pattern layer serving as the ink discharge port opening end is formed. Was exposed on the surface.

  Thereafter, by performing anisotropic etching from the back surface of the silicon substrate 1, a through hole was formed and the ink supply port 10 was formed. Here, tetramethyl hydroxide (TMAH) was used as an etching solution. In the anisotropic etching process, the ink flow path pattern layer and the ink discharge port pattern layer were also wet etched at the same time, and an ink discharge mechanism portion of the ink jet recording head was obtained as shown in FIG. .

  The ink ejection mechanism portion of the above-described ink jet recording head can be made into an ink jet recording head through the following steps. The silicon substrate 1 patterned with terminals for driving the ink discharge pressure generating element 2 is coupled, and a base plate made of aluminum or alumina ceramic is joined to the silicon substrate 1 for heat dissipation, and then a holder and ink for holding each member An ink jet head is assembled by combining ink tanks for supply, and a unit having a function as an ink jet recording head is obtained.

  When an alkaline ink having a pH of 10 was discharged and evaluated using the obtained ink jet recording head, good printing could be obtained. Moreover, when the ink jet recording head was immersed in the ink at 60 ° C. for 3 months and then evaluated for printing, good printing could be obtained.

  The same effect was obtained even when a silicon substrate having a (110) plane crystal orientation was used.

(Example 2)
FIG. 2 shows a manufacturing flow of an ink discharge mechanism portion in the ink jet recording head of Embodiment 2 of the present invention, and an outline thereof will be described. 2 corresponds to a cross section of the AA ′ portion of FIG.

  Specifically, the silicon substrate 11 having the (110) plane crystal orientation was used instead of the silicon substrate 1 having the (100) plane crystal orientation as the silicon substrate, and the silicon oxide film 7 was used as the nozzle material. The same method as in Example 1 was used except that the silicon nitride film 8 was used instead of the above.

  When an alkaline ink having a pH of 10 was discharged and evaluated using the obtained ink jet recording head, good printing could be obtained. In addition, when the ink jet recording head was immersed in the ink at 60 ° C. for 3 months and then evaluated for printing, good printing could be obtained.

  The same effect was obtained even when a silicon substrate having a crystal orientation of (100) plane was used.

FIG. 3 is a schematic cross-sectional view showing a manufacturing flow in the ink jet recording head according to Example 1 of the invention. It is a typical sectional view showing a manufacturing flow in an ink jet recording head concerning Example 2 of the present invention. 1 is a schematic perspective view showing a part of an inkjet recording head according to an embodiment of the present invention in a broken state. It is typical sectional drawing which shows the manufacture flow of the inkjet recording head by a prior art.

Explanation of symbols

1: Silicon substrate [substrate having crystal orientation of (100) plane]
2: Ink discharge pressure generating element 3: Thermal oxide film 4: Polysilicon 5: Positive resist 6: Aluminum 7: Silicon oxide film 8: Silicon nitride film 9: Ink discharge port 10: Ink supply port 11: Silicon substrate [( 110) Substrate having a plane crystal orientation]
12: Pattern layer 13: Inorganic material layer

Claims (7)

(A) forming a first layer made of a silicon-based compound on a substrate provided with an ink discharge pressure generating element for discharging ink;
(B) patterning the first layer to form an ink flow path pattern layer;
(C) forming a second layer made of a metal material on the ink flow path pattern layer;
(D) patterning the second layer to form an ink discharge port pattern layer;
(E) forming a nozzle material layer at a position covering the ink flow path pattern layer and the ink discharge port pattern layer on the substrate;
(F) flattening the surface of the nozzle material layer to expose a part of the ink discharge port pattern layer serving as an ink discharge port opening end on the surface;
(G) removing the ink flow path pattern layer and the ink discharge port pattern layer by wet etching to form an ink flow path and an ink discharge port;
An ink jet recording head manufacturing method comprising:   2. The method of manufacturing an ink jet recording head according to claim 1, wherein polysilicon is used as the silicon compound.   The method for manufacturing an ink jet recording head according to claim 1, wherein any one of Al, Al—Cu, Al—Si, and Al—Si—Cu is used as the metal material.   The method of manufacturing an ink jet recording head according to claim 1, wherein in the step (d), a tapered ink discharge port pattern layer is formed.   The method for manufacturing an ink jet recording head according to claim 1, wherein the nozzle material layer is formed of a silicon oxide film or a silicon nitride film.   The method of manufacturing an ink jet recording head according to claim 1, further comprising: (h) performing a water repellent treatment on the surface of the nozzle material layer. An ink jet recording head manufactured by the method according to claim 1, wherein an ink discharge port is provided on a substrate provided with a plurality of ink discharge pressure generating elements for discharging ink, An ink channel that communicates with an ink ejection port and can introduce the ink at a position where the ink ejection pressure generating element can act, and the ink channel and the ink are formed by a nozzle material layer bonded to the substrate. An ink jet recording head having discharge ports formed therein.

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