JP2006168141A - Ink jet recording head and manufacturing method thereof. - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording head capable of forming a filter capable of preventing entry of dust, foreign matter, etc. into a nozzle or the like at the same time as an ink supply part and obtaining a good yield at low cost, and a method for manufacturing the same. .
An etching resistant mask and an etching resistant mask provided on the back surface of a silicon substrate when an ink supply portion is formed on the silicon substrate by anisotropic etching in order to prevent dust and foreign matter from entering the ink discharge port. A filter comprising a protective film for protecting the film is formed simultaneously with the etching.
[Selection] Figure 1

Description

  The present invention relates to an ink jet recording head used in an ink jet recording system and a method for manufacturing the same.

  As an example of a general inkjet recording head, an inkjet recording head that ejects ink in a direction perpendicular to the surface of an ejection pressure energy generating element for ejecting ink will be described as an example. On the other hand, a method in which an electric control circuit for driving an ink discharge pressure generating element is built in a substrate by using a semiconductor manufacturing technique has been proposed. The high-performance inkjet recording head described above supplies ink to a plurality of ink discharge ports (nozzles) by penetrating the substrate from the back of the substrate and supplying ink to each nozzle from a common ink supply port. It has a structure to do. Further, when a Si substrate is used as the substrate of the ink jet recording head as described above, as disclosed in Patent Document 1, the ink supply port is formed by using the Si anisotropic etching technique. Is possible.

  Here, one of the reliability required for the ink jet recording head is concerned about a printing defect called non-ejection (no ink is ejected from the target nozzle) due to nozzle clogging. As a cause, it is generally said that the ink is solidified and cannot be discharged, or dust enters the nozzle and the ink supply to the nozzle is interrupted. For the former cause, a protection function is provided or a recovery mechanism is provided when solidified. Furthermore, the details of the latter cause can be broadly classified as follows.

1. 1. Dust and foreign matter enter during the manufacturing process of the ink jet recording head. When dust or foreign matter enters from the outside of the ink jet recording head, dust enters the nozzle, the ink supply to the nozzle is shut off, and printing failure occurs.

  In particular, 2. As a matter of concern, in the case where the ink supply is structured to be separable from the ink jet recording head, there is a high possibility that the connection portion will cause a problem. Conventionally, as a countermeasure against such a cause, the above-described 1. As for the above-mentioned 2. For example, a filter is provided in the vicinity of the ink supply port of the ink jet recording head. However, 2. In the case of providing a filter at the ink supply port as a countermeasure of the above, in the conventional one that manufactures and mounts a separate filter from the inkjet recording head as a separate component, the manufacturing cost, component cost, quality control, or connection between components Regarding reliability and the like, it is not always satisfactory, and further improvement is desired.

Patent Document 2 is disclosed as an invention for solving these problems. FIG. 5A shows an ink jet recording head having a filter structure according to the prior art. In this ink jet recording head, an etching resistant mask 3 such as SiO ₂ or SiN is provided on the back surface of the Si substrate 1, and a filter structure is formed with the etching resistant mask 3 when forming the ink supply unit 11 by anisotropic etching. A method has been reported.
JP-A-9-11479 JP 2000-94700 A

  However, in the above invention, an insulating film such as SiO2 or SiN film is used as an etching-resistant mask material. However, these films are usually formed as a deposited film such as sputtering or CVD. It is difficult to form. In addition, it is very difficult to make these films defect-free because they are exposed to various liquids in the post-process for forming the ink discharge pressure generating element, and there are also minor scratches due to transport in the semiconductor manufacturing apparatus. It is difficult to.

  For this reason, as shown in FIG. 5B, the specified ink supply port width dimension X is larger than the specified dimension, such as the ink supply port width Y, due to this defective portion (pinhole) 14. In some cases, the defect becomes larger. Therefore, the ink ejection characteristics are affected. Further, as shown in FIG. 5C, as the image quality of the ink jet recording head is improved, the fineness of the discharge port is advanced, and the minute breakage of the filter due to the defective portion (pinhole) 14 cannot be ignored. Is in the situation. For the reasons described above, there is a problem that a good yield cannot be obtained. Therefore, formation of a defect-free etching mask is a great demand in micromachine technology such as head manufacturing.

  Therefore, the present invention solves the above-described problems in the conventional ones, and can be formed at the same time as an ink supply unit with a filter that can prevent the entry of dust, foreign matter, etc. into nozzles and the like. An object of the present invention is to provide an ink jet recording head capable of obtaining a good yield and a method for manufacturing the same.

  In order to solve the above-mentioned problems, the present invention is characterized in that an ink jet recording head and a manufacturing method thereof are configured as follows.

  That is, in an inkjet recording head using an Si substrate and forming an ink supply pressure generating element and an ink supply unit for supplying ink to an ink discharge port on the substrate, an etching-resistant mask is provided on the Si substrate, and the Si substrate In addition, when the ink supply unit is formed by anisotropic etching, a filter composed of an anti-etching mask and a protective film for protecting the anti-etching mask is formed simultaneously with the ink supply unit. Further, when the diameter of the filter is A and the diameter of the ink ejection port is B, the relationship of A ≦ B is established. Further, the Si substrate is characterized in that a crystal plane orientation of a surface where etching is started is a <100> plane or a <110> plane. In addition, the protective film for protecting the etching resistant mask is made of a photosensitive resin or a thermoplastic resin.

  When the ink supply part is formed on the Si substrate by anisotropic etching, the inventors of the present invention are able to suppress the occurrence of filter breakage due to defects (pinholes) existing in the etching resistant mask. The present inventors have found a method of forming a filter structure using a protective film that also serves as a mask and protects defects in the etching resistant layer.

  With the above configuration, the occurrence of filter breakage due to defects (pinholes) present in the etching resistant mask can be suppressed to the minimum, and the yield of the filter forming process can be improved. Furthermore, in order to complete an actual ink jet recording head, an electrical signal is supplied from the outside necessary for driving the functional element or cutting for separating the element from a substrate arranged in a large number in a later process. In this invention, a filter structure is built in the functional element portion (generally also referred to as a device) of the ink jet recording head. Therefore, an ink jet recording head with a high yield can be manufactured.

  According to the present invention, when the ink supply part is formed on the Si substrate by anisotropic etching, the anti-etching mask and the protective film that protects the anti-etching mask are used to prevent entry of dust, foreign matter, and the like. The filter can be formed simultaneously with the ink supply unit. Thereby, the occurrence of filter breakage due to defects (pinholes) existing in the etching resistant mask can be suppressed to the minimum, and the yield of the filter forming process can be improved.

  Further, in order to complete the ink jet recording head, in order to send an electrical signal necessary for separating individual elements from a large number of substrates arranged in a later process or driving functional elements. Connection (also referred to as electrical mounting) and assembly of a structural member for supplying ink is required. In the present invention, a filter structure is formed by a functional element portion (generally also referred to as a device) of an ink jet recording head. This makes it possible to manufacture an ink jet recording head with a high yield without introducing dust generated during the post-manufacturing process.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

FIG. 4 is a schematic diagram of an ink jet recording head manufactured in the present embodiment. This ink jet recording head (liquid discharge head) has a Si 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 Si substrate 1, an ink supply port (liquid supply port) 11 formed by anisotropic etching of Si using the SiO ₂ film 3 as a mask is opened between two rows of ink discharge pressure generating elements 2. Yes. On the Si substrate 1, an ink ejection port (liquid ejection port) 7 opened above each ink ejection pressure generating element 2 and an ink communicating from the ink supply port 11 to each ink ejection port 7 by an orifice plate material 9. A flow path (liquid flow path) is formed.

  This ink jet recording head is arranged so that the surface on which the ink supply port 11 is formed faces the recording surface of the recording medium. The ink jet recording head applies an ink liquid from the ink discharge port 7 by applying a pressure generated by the ink discharge pressure generating element 12 to the ink (liquid) filled in the ink flow path via the ink supply port 11. Recording is performed by discharging droplets and attaching them to a recording medium.

  The ink jet recording head can be mounted on an apparatus such as a printer, a copying machine, a facsimile having a communication system, a word processor having a printer unit, or an industrial recording apparatus combined with various processing apparatuses. By using this ink jet recording head, recording can be performed on various recording media such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics. In the present invention, “recording” 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. .

In particular, in forming the ink supply port of this ink jet recording head, it is common to use an insulating film such as a SiO ₂ or SiN film as the etching resistant mask 3, but these films are usually volume films such as sputtering and CVD. Therefore, it is difficult to form these films without defects. Therefore, the filter may be defective due to the defective portion (pinhole).

  Therefore, in the present invention, in order to suppress the occurrence of filter breakage due to defects (pinholes) present in the etching resistant mask, a protective film that also serves as a patterning mask for the etching resistant layer and protects the defects in the etching resistant layer is provided. A method for forming a filter structure by using it was found.

  Examples of the ink jet recording head are shown below.

  1A to 1F are schematic cross-sectional views showing a basic manufacturing process of the ink jet recording head of the present invention. FIG. 1 is a cross-sectional view taken along line A-A ′ of FIG. 5.

The silicon substrate 1 shown in FIG. 1A has a crystal orientation of <100> plane. On this silicon substrate, a plurality of ink discharge pressure generating elements 2 such as heating resistors are arranged. Further, the back surface of the substrate 1 including the SiO ₂ film 3 is entirely covered with a polysilicon film 4. A positive resist is applied to the surface of the substrate 1 by spin coating or the like, dried, and a polysilicon film layer 4 other than the SiO ₂ film is in contact with the silicon surface on the back surface of the substrate 1 as shown in FIG. Is removed by dry etching or the like, and the positive resist is peeled off. This SiO ₂ film 3 serves as an etching mask for anisotropic etching.

Next, as shown in FIG. 1C, a SiO ₂ film patterning mask layer 6 made of a polyether amide resin in close contact with the SiO ₂ film 3 was formed. In one embodiment of the present invention, a thermoplastic polyether amide (manufactured by Hitachi Chemical Co., Ltd., trade name: HL-1200) was used as the polyether amide resin layer. The above thermoplastic polyether amide is commercially available as a solution in a solvent. This becomes a patterning mask for patterning the SiO ₂ film 3. Also, it plays a role of protecting defects (pinholes) of the SiO ₂ film 3. The SiO ₂ film patterning mask layer 6 is formed by coating the SiO ₂ film patterning mask layer on the entire surface of the SiO ₂ film 3 by spin coating or the like, thermally curing, and then applying and drying a positive resist by spin coating or the like. It is formed by performing exposure and development using ultraviolet light, deep UV light, etc., removing the exposed SiO ₂ film patterning mask layer by dry etching or the like, using the positive resist pattern as a mask, and peeling the positive resist. The

  This patterning mask layer 6 was formed with a pattern having a filter structure shown in FIG. This hole 12 becomes a hole through which actual ink passes. Therefore, it is needless to say that the hole diameter is as small as possible and that the filter performance is high when it is arranged finely. On the other hand, since pressure loss (flow resistance) occurs in the filter portion and the ink flow becomes worse, the ink discharge speed is adversely affected. Therefore, it is not preferable to form a filter with a fine size unnecessarily. Therefore, there is a trade-off between the filter performance and the flow resistance. Therefore, in the present invention, the hole diameter is designed to be 5 μm, and the holes described above are arranged at equal intervals so that the distance between adjacent holes is also 5 μm as shown in FIG. Here, from the outermost periphery of the arranged holes, the dimension obtained by adding the side etch amount is the size of the ink supply port 13.

  In the present invention, as described above, an example in which the filter hole diameter is 5 μm and the interval between adjacent holes is also 5 μm has been described. However, it is suitable for each ink jet print head, that is, the above trade-off relationship can be achieved. It is desirable to appropriately adjust the filter hole diameter and the arrangement interval. However, the interval between adjacent filter holes should not be set beyond the side etching amount.

  Next, a pattern 5 serving as an ink flow path portion is formed of a soluble resin layer on the substrate 1 including the ink discharge pressure generating element 2. The dissolvable resin layer 5 (ODUR: manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied with spin coating or the like, followed by exposure and development with ultraviolet light or deep UV light, etc., to form a pattern.

  Next, as shown in FIG. 1D, a coating resin layer 9 (CR) is formed on the soluble resin layer 5 by spin coating or the like. A water repellent layer 8 is formed on the coating resin layer 9 by laminating a dry film or the like. The ink discharge port 7 is formed by performing exposure and development using ultraviolet rays, deep UV light, or the like.

Next, as shown in FIG. 1E, the surface and side surfaces of the substrate 1 on which the dissolvable resin layer 5 and the covering resin layer 9 are patterned are applied by spin coating or the like, Cover with 10. The protective material 10 is a material that can sufficiently withstand a strong alkaline solution used when performing anisotropic etching, and therefore, it is possible to prevent deterioration of the water-repellent layer 8 and the like due to anisotropic etching. It becomes. The SiO ₂ film 3 on the back surface of the substrate 1 is patterned by wet etching or the like using the SiO ₂ film patterning mask layer 6 as a mask to expose the silicon surface that is the starting surface for anisotropic etching.

  Next, an ink supply port 11 is provided in the substrate 1. The ink supply port 11 is formed by chemically etching the substrate, for example, anisotropic etching with a strong alkaline solution of TMAH or KOH. The forming method will be described in order.

  The formation mechanism of the ink supply port penetrating in the thickness direction of the Si substrate will be described with reference to FIGS. 3A to 3D. FIG. 3A shows a relatively early stage of the etching start. However, Si is anisotropically etched almost faithfully to each filter hole diameter (5 μm in this embodiment). In FIG. 3B, side etching occurs as etching progresses, and the hole diameter of the Si substrate is wider than the actual hole diameter. FIG. 3C shows a pattern when etching further proceeds than in FIG. 3B. FIG. 3D shows a state where etching is finally completed.

  As described above, a feature of the present invention is a method of simultaneously forming an ink supply port that penetrates the filter and the Si substrate using the side etching described above.

  Subsequently, as shown in FIG. 1 (F), the protective material 10 is removed. Further, the soluble resin layer 5 is eluted from the ink discharge port 7 and the ink supply port 11 to form an ink flow path and a foaming chamber. The soluble resin layer 5 can be removed by developing and drying the whole surface with deep UV light, followed by development and drying. If necessary, ultrasonic immersion is sufficient.

  The substrate 1 on which the nozzle portion has been formed by the above steps is separated, cut, and chipped by a dicing saw or the like, and electrical joining for driving the ink discharge pressure generating element 2 is performed, and then a chip tank for supplying ink The main manufacturing process as an ink jet recording head is completed by connecting the members.

  In the manufacturing method of the ink jet recording head of the present invention, the manufacturing method is not limited to the above-described manufacturing methods and materials, and other manufacturing methods and materials can be used. However, the Si substrate is used as the substrate, the crystal orientation of the Si substrate on which the functional element such as the inkjet recording element is formed is the <100> plane, the orifice plate 9 of the inkjet recording head, the ink discharge port Forming the ink supply port 11 by the Si anisotropic etching technique from the back surface of the Si substrate on which 7 is formed (opposite the surface on which the functional elements of the inkjet recording head are formed) constitutes the present invention. It becomes an important structure above.

  As another embodiment, the polyether amide resin layer is described as one embodiment of the filter. However, as another embodiment, CR (photosensitive resin) 9 can be used. The reason for this is that it has ink resistance, and even if the filter has a large area, a smooth and strong filter structure equivalent to that of the poly-ether amide resin can be formed.

FIG. 3 is a schematic cross-sectional view showing a basic manufacturing process of the ink jet recording head according to Example 1 of the invention. It is the schematic diagram seen from the back surface of the inkjet recording head showing a filter part. It is a typical sectional view explaining the filter formation method by anisotropic etching of the ink jet recording head concerning Example 1 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. 1 is a schematic cross-sectional view of an ink jet recording head according to the prior art of the present invention.

Explanation of symbols

1 Si substrate 2 Ink discharge pressure generating element 3 Anti-etching mask (SiO ₂ )
4 Polysilicon 5 Dissolvable resin layer (ODUR: manufactured by Tokyo Ohka)
6 SiO2 film patterning mask layer and filter material 7 Ink discharge port 8 Water repellent layer 9 Covered photosensitive resin layer (CR)
10 Protective Material 11 Ink Supply Port 12 Filter Hole 13 Filter 14 Etching-resistant Mask Defect

Claims (8)

In an inkjet recording head that uses a Si substrate and forms an ink supply pressure generating element on the substrate and an ink supply unit that supplies ink to an ink discharge port.
An etching resistant mask is provided on the Si substrate, and when the ink supply portion is formed on the Si substrate by anisotropic etching, a filter composed of the etching resistant mask and a protective film that protects the etching resistant mask is provided with the ink. An ink jet recording head formed simultaneously with a supply unit.   2. The ink jet recording head according to claim 1, wherein when the aperture of the filter is A and the ink ejection aperture is B, a relationship of A ≦ B is established.   3. The ink jet recording head according to claim 1, wherein the Si substrate has a <100> plane or a <110> plane as a crystal plane orientation of a plane where etching is started.   4. The ink jet recording head according to claim 1, wherein the protective film for protecting the etching resistant mask is made of a photosensitive resin or a thermoplastic resin. In a method of manufacturing an ink jet recording head using an Si substrate and forming an ink supply pressure generating element on the substrate and an ink supply unit for supplying ink to an ink discharge port,
An etching resistant mask is provided on the Si substrate, and when the ink supply portion is formed on the Si substrate by anisotropic etching, a filter composed of the etching resistant mask and a protective film that protects the etching resistant mask is provided with the ink. A method of manufacturing an ink jet recording head, wherein the ink jet recording head is formed simultaneously with a supply unit.   6. The method of manufacturing an ink jet recording head according to claim 5, wherein the relationship of A ≦ B is established when the aperture of the filter is A and the ink ejection aperture is B.   7. The method of manufacturing an ink jet recording head according to claim 5, wherein the Si substrate has a <100> plane or a <110> plane as a crystal plane orientation of an etching start surface.   8. The method of manufacturing an ink jet recording head according to claim 5, wherein the protective film for protecting the etching resistant mask is made of a photosensitive resin or a thermoplastic resin.