JP2016215466A - Manufacturing method for liquid discharge head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a liquid discharge head which can execute hydrophilization of a discharge port face by a simplified process and suppress costs for manufacturing the liquid discharge head.SOLUTION: The manufacturing method for a liquid discharge head includes: a step for forming, on a first surface of a silicon substrate 1, a flow-path forming member 4 which comprises a discharge port 5 and has a discharge port face 7, a discharge port forming face, formed of resin materials including epoxide resin; and a hydrophilization processing step for contacting alkali aqueous solution with the discharge port face, the discharge port forming face, at temperature of 90°C or less for over 30 minutes, where the alkali solution contains at least one of tetra methyl ammonium hydride, sodium hydroxide, potassium hydroxide as alkali compound and the alkali solution contains alkali compound of 5 mass% or more and 60 mass% or less.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for manufacturing a liquid discharge head.

  A liquid discharge head applied to an ink jet recording method or the like generally has a liquid flow path, a discharge energy generation unit provided in a part of the liquid flow path, and a fine discharge for discharging liquid by the energy of the discharge energy generation unit. Has an exit. As a method for manufacturing such a liquid discharge head, in Patent Document 1, a liquid flow path mold is patterned with a photosensitive resin material on a substrate on which an electrothermal conversion element serving as a discharge energy generating element is formed. A coating resin layer for forming a liquid flow path was applied and formed on the substrate so as to cover the mold, and a discharge port communicating with the liquid flow path mold was formed in the coating resin layer, and then used for the mold. A method of manufacturing a liquid discharge head obtained by removing a photosensitive resin material is disclosed.

  By making the surface (discharge port surface) on which the discharge ports are formed water repellent or hydrophilic, the droplets to be discharged are discharged well from the discharge ports, enabling higher-definition printing.

JP 2009-119725 A

  When a water repellent material or a hydrophilic material is laminated in order to make the discharge port surface water repellent or hydrophilic, a process of applying each material and an increase in cost due to the material occur.

  The object of the present invention is to solve the above problems. That is, the present invention provides a method of manufacturing a liquid discharge head that suppresses the increase in cost by making the discharge port surface hydrophilic by a very simplified process.

  The present invention includes a step of forming a flow path forming member provided with a discharge port on a first surface of a silicon substrate, the discharge port surface being a formation surface of the discharge port formed of a resin material containing an epoxy resin, A hydrophilic treatment step in which an alkaline aqueous solution is brought into contact with a discharge port surface, which is a forming surface of the discharge port, at a temperature of 90 ° C. or lower for 30 minutes or more. The liquid discharge head manufacturing method includes at least one of hydride, sodium hydroxide, and potassium hydroxide, and the alkaline aqueous solution contains the alkali compound in an amount of 5% by mass to 60% by mass.

  According to the above configuration, the discharge port surface can be made hydrophilic by a simple process, and a good quality liquid discharge head can be provided at low cost.

1 is a perspective view illustrating a structure of an ink jet head according to an embodiment of a liquid discharge head according to the present invention. It is typical sectional drawing which shows the manufacturing process of the manufacturing method of the inkjet head which becomes one Embodiment of this invention. It is typical sectional drawing which shows the other manufacturing method of the inkjet head which becomes one Embodiment of this invention. It is typical sectional drawing which shows the further another manufacturing method of the inkjet head which becomes one Embodiment of this invention.

  Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a perspective view schematically showing the structure of an ink jet head according to an embodiment of the liquid discharge head of the present invention. 1 will be described with reference to FIG. In the present embodiment, a method for manufacturing a liquid discharge head according to the present invention will be described with reference to a schematic cross-sectional view when the ink jet head of FIG. 1 is cut along line AB. A manufacturing flow for this embodiment is shown in FIGS.

1. Preparation of substrate (Fig. 2 (a))
First, a substrate 1 as shown in FIG. As such a substrate 1, a silicon substrate is generally used.

  Disposed on the first surface of the substrate 1 is an ejection energy generating unit 2 on which an element such as an electrothermal conversion element or a piezoelectric element is formed. By such an ejection energy generation unit 2, ejection energy for ejecting droplets is given to the ink, and recording is performed. For example, when an electrothermal conversion element is used as the ejection energy generating unit 2, the element heats nearby ink, thereby causing a state change in the ink and generating ejection energy. For example, when a piezoelectric element is used, ejection energy is generated by mechanical vibration of the element.

  These discharge energy generating units 2 are connected to control signal input electrodes (not shown) for operating the elements. Further, a protective layer (not shown) for the purpose of improving the durability of the elements of the discharge energy generating unit 2 and an adhesion improving layer for the purpose of improving the adhesion of the flow path forming member 4 to be described later to the substrate 1. Various functional layers such as (not shown) are provided as necessary.

2. Formation of ink flow path (liquid flow path) mold 3 (FIG. 2B)
Next, as shown in FIG. 2B, a positive resist layer is formed on the first surface of the substrate 1 including the ejection energy generating unit 2, and this is patterned to form the mold 3. The positive resist used here is required to have resistance to a coating solvent for a photosensitive resin that will be a flow path forming member 4 described later. Therefore, as the positive resist, a polymer main chain decomposition type positive resist mainly composed of methacrylic acid ester having excellent solvent resistance, and a main chain decomposition type positive resist mainly composed of polymethylisopropenyl ketone. It is preferable to use a resist.

  Examples of the polymer main chain decomposition type positive resist mainly composed of methacrylic acid ester include homopolymers such as polymethyl methacrylate and polyethyl methacrylate, methyl methacrylate and methacrylic acid, acrylic acid, glycidyl methacrylate, and phenyl methacrylate. And the like. In the present invention, it is particularly preferable to use polymethylisopropenyl ketone having excellent overall characteristics such as sensitivity, resolution, and solvent resistance.

  Patterning can be performed by eluting the exposed portion by a general photolithography technique.

3. Formation of discharge port (FIGS. 2C and 2D))
Next, a photosensitive resin for forming the flow path forming member 4 is formed on the substrate 1 including the liquid flow path mold 3 by a method such as spin coating, roll coating, or slit coating (FIG. 2). (C)). Since the photosensitive resin functions as a flow path forming member 4 that defines a liquid flow path 10 and a discharge port 5 described later, high mechanical strength as a structural material, adhesion to a base, and ink resistance At the same time, a resolution for patterning a fine pattern of the discharge port 5 is required. As a material satisfying these characteristics, a photocationic polymerization type photosensitive resin composition containing an epoxy resin can be suitably used. In particular, a negative photosensitive resin composition having a photosensitive wavelength different from that of the positive resist constituting the mold 3 is preferable.

  Examples of the epoxy resin used in the photosensitive resin composition include a reaction product of bisphenol A and epichlorohydrin having a molecular weight of about 900 or more, a reaction product of bromobisphenol A and epichlorohydrin, phenol novolac, or o-cresol. Reaction product of novolak and epichlorohydrin, as described in JP-A-60-161973, JP-A-63-221121, JP-A-64-9216, JP-A-2-140219 Examples thereof include polyfunctional epoxy resins having a cyclohexane skeleton.

  In the above-described epoxy compound, a compound having an epoxy equivalent of 2000 or less, more preferably 1000 or less, is preferably used. This is because if the epoxy equivalent exceeds 2000, the crosslinking density is lowered during the curing reaction, which may cause problems in adhesion and ink resistance.

  As the photocationic polymerization initiator for curing the epoxy resin, a compound that generates an acid by light irradiation can be used. The compound that generates an acid upon irradiation with light is not particularly limited. For example, aromatic sulfonium salts include “TPS-102”, “TPS-103”, “TPS” commercially available from Midori Kagaku Co., Ltd. -105 "," MDS-103 "," MDS-105 "," MDS-205 "," MDS-305 "," DTS-102, "DTS-103", "SP" commercially available from Adeka Corporation -170 "," SP-172 ", etc. (all are trade names), and aromatic iodonium salts are" DPI-105 "," MPI-103 "," MPI "commercially available from Midori Chemical Co., Ltd. -105 "," BBI-101 "," BBI-102 "," BBI-103 "," BBI-105 ", etc. (all are trade names) can be preferably used. Further, the addition amount can be any addition amount so as to achieve the target sensitivity, but it can be preferably used in a range of 0.5 to 5% by mass with respect to the epoxy resin. Moreover, you may add and use "SP-100" (brand name) etc. which are marketed, for example from ADEKA Corporation as a wavelength sensitizer as needed.

  Furthermore, additives and the like can be appropriately added to the photosensitive composition as necessary. For example, the additive includes a flexibility imparting agent for the purpose of lowering the elastic modulus of the epoxy resin, or a silane coupling agent in order to obtain further adhesion to the base.

Next, as shown in FIG. 2D, the photosensitive resin layer to be the flow path forming member 4 is patterned by a general photolithography technique to form the discharge ports 5. Thereafter, heat treatment may be performed as necessary to accelerate the curing reaction of the flow path forming member 4.
The flow path forming member 4 is formed by two members, ie, a flow path wall member that defines the wall surface of the ink flow path and an orifice plate that defines the discharge port, in addition to the single layer of the photosensitive resin layer as described above. You can also In this case, the orifice plate serving as the discharge port surface, which is the discharge port forming surface, is made of a resin material containing an epoxy resin.

  As described above, after the discharge port is formed, a hydrophilic treatment is performed on the discharge port surface. The hydrophilic treatment is performed by bringing the alkaline aqueous solution into contact with the discharge port surface, which is the discharge port formation surface, at a temperature of 90 ° C. or lower for 30 minutes or more. The alkaline aqueous solution contains at least one of tetramethylammonium hydride (hereinafter referred to as TMAH), sodium hydroxide (hereinafter referred to as NaOH), and potassium hydroxide (hereinafter referred to as KOH) as an alkaline compound. And alkaline aqueous solution contains 5 to 60 mass% of alkali compounds.

  If the concentration of the alkali compound is less than 5% by mass or the treatment time is less than 30 minutes, sufficient hydrophilicity cannot be imparted, and a deviation may occur in the ejection direction of a liquid such as ink. When the concentration exceeds 60% by mass or the temperature exceeds 90 ° C., elution of the epoxy resin constituting the discharge port surface or peeling from the substrate may occur.

  From the viewpoint of hydrophilization, the alkaline aqueous solution preferably contains 10% by mass or more, more preferably 20% by mass or more of the alkali compound. The treatment time is preferably 1 hour or longer, and the alkaline aqueous solution is preferably brought into contact with the discharge port surface for 1 hour or longer. Furthermore, the treatment temperature is preferably 30 ° C. or higher and 80 ° C. or lower. It is preferable to optimize these concentrations, temperatures, and times by appropriately combining them. The higher the concentration and temperature, the shorter the time for hydrophilization treatment, and the lower the concentration, the higher the temperature or the longer the time.

  There are many unopened epoxy groups and inactivated hydroxyl groups on the discharge port surface formed of epoxy resin, and by contacting with an alkaline aqueous solution, the epoxy groups are opened or hydroxyl groups are activated, A hydrophilic hydroxyl group is formed. This is presumed to improve the hydrophilicity of the discharge port surface. The term “hydrophilization” as used herein refers to the case where the measured value of the dynamic contact angle with pure water is less than 25 °.

  In particular, in the present invention, part or all of the formation of the liquid supply path (ink supply path) described below can be performed with the alkaline aqueous solution used in this hydrophilization treatment process, which simplifies the process and reduces costs. Can be achieved.

4). Formation of ink supply path (FIGS. 2E and 2F)
Next, an ink supply path (liquid supply path) 9 penetrating the substrate 1 is formed. As shown in FIG. 2E, an etching mask 6 for forming the ink supply path 9 is formed on the second surface (back surface) facing the first surface of the substrate 1. The ink supply path 9 is preferably formed using the etching mask 6. When the substrate 1 is silicon, the ink supply path can be formed by anisotropic etching using an alkaline etching solution. As the etching solution, an alkaline aqueous solution used in the hydrophilization treatment can be used. Silicon substrates having <100> and <110> orientations as crystal orientations can be selectively etched in the depth direction and the width direction with respect to the direction of etching by performing alkaline chemical etching. Can be obtained. In particular, the etching depth of a silicon substrate having a <100> crystal orientation can be controlled because the etching depth is geometrically determined by the etching width. For example, a hole that narrows with an inclination of 54.7 ° in the depth direction from the etching start surface can be formed with high accuracy.

  The type and concentration of the etching liquid, the processing temperature, and the processing time can be arbitrarily set so as to obtain a desired etching rate according to the thickness of the silicon substrate to be used, the opening width of the ink supply path 9, and the like. Further, the etching mask 6 may be formed in advance in a process before this process. Further, the formation of the ink supply path 9 is not limited to the etching using the alkaline aqueous solution as described above, and may be a process by dry etching, sandblasting, or the like. Further, a lead hole can be formed from the second surface of the substrate 1 by a laser ablation (LA) method or the like to shorten the etching time. FIG. 2 (f) shows an aspect in which the ink supply path 9 is formed by causing the alkaline aqueous solution 8 to act on the back surface of the substrate 1 at the same time that the discharge port surface 7 is made hydrophilic using the alkaline aqueous solution 8.

5. Formation of ink flow path (FIGS. 2 (g) and (h))
Next, the etching mask 6 is removed (FIG. 2G), and the ink flow path mold 3 is removed to form the ink flow path 10 (FIG. 2H). The etching mask 6 can be removed by dissolution using an appropriate organic solvent, dry etching using oxygen gas, or the like. The removal of the mold 3 is performed by increasing the solubility by irradiating light of the photosensitive wavelength of the positive resist used in the mold 3, and removing the etching mask 6 if it can be dissolved in an organic solvent that removes the etching mask 6. At the same time, it can be removed with another stripping solution or the like. For the removal of the etching mask 6 and the mold 3, optimum conditions may be appropriately selected within a range that does not affect the substrate 1 and the flow path forming member 4. In particular, it is preferable to select a condition that does not affect the hydrophilicity of the hydrophilic discharge port surface 7.

  Further, after undergoing a cutting and separating step (not shown), the coating resin is completely cured by performing a heat treatment as necessary. Further, a member (not shown) for supplying ink and an electrical connection (not shown) for driving the ink discharge pressure generating element are performed to complete the ink jet head.

  As shown in FIG. 2F, in order to make the discharge port surface 7 hydrophilic, the step of bringing the alkaline aqueous solution 8 into contact with the discharge port surface 7 is performed after the discharge port 5 is formed (FIG. 2D). Or after the formation of the etching mask 6 (FIG. 2E), it is preferably performed simultaneously with the formation of the ink supply path 9 (FIG. 2F). When the hydrophilic treatment and the formation of the ink supply path 9 are performed simultaneously as shown in FIG. 2 (f), the ink supply path 9 is formed within the range of the concentration and temperature of the aqueous alkali solution selected for the hydrophilic treatment. You can go for the time.

  In the embodiment shown in FIG. 2, the example in which the hydrophilic treatment process also serves as the ink supply path forming process is shown, but the present invention is not limited to this and may be performed separately. In particular, when the hydrophilic treatment is performed after the etching mask 6 is formed on the second surface of the substrate 1, the etching of the second surface of the mask opening of the etching mask 6 proceeds to form at least a part of the ink supply path. Can do.

FIG. 3A shows a state in which a part 11 of the ink supply path is formed in the hydrophilic treatment process after the process of FIG. Thereafter, in order to form the remaining ink supply path, a protective film 12 that protects the hydrophilic discharge port surface 7 is formed as shown in FIG. 3B, and the remaining ink supply path is etched to supply ink. Complete road 9. For etching the remaining ink supply paths, other methods for forming the ink supply paths described above, for example, dry etching, sandblasting, LA method, and the like can be used as appropriate. The protective film 12 is preferably made of a material that does not affect the hydrophilicity of the discharge port surface 7 that has been subjected to a hydrophilic treatment. In addition, since it is necessary to finally remove the protective film 12, a material that can be removed under optimum conditions as long as it does not affect the substrate 1 and the flow path forming member 4 may be selected. In particular, a material that can select a removal condition that does not affect the hydrophilicity of the hydrophilic discharge port surface 7 is preferable. Examples of such a material include a resist material containing cyclized rubber.
Further, after forming a part 11 of the ink supply path as shown in FIG. 4A before the hydrophilization process, the completion of the ink supply path 9 and the hydrophilic process are performed as shown in FIG. 4B. You may do it at the same time.

  As described above, it is possible to provide an ink jet head manufacturing method capable of manufacturing the hydrophilic discharge port surface 7 that enables highly accurate discharge by a simple and inexpensive method. Furthermore, it is possible to provide an ink jet head that does not cause problems such as deviation in the ink ejection direction and non-ejection.

  Examples of the present invention are shown below. The results of all Examples and Comparative Examples are shown in Table 1. In the examples, “%” is based on mass.

Example 1
Polymethylisopropenyl ketone (trade name: “ODUR-1010”, Tokyo Ohka Kogyo Co., Ltd.) is used as a positive resist on a substrate 1 (FIG. 2A) on which an electrothermal conversion element as a discharge energy generating unit 2 is formed. Were applied by spin coating. Subsequently, prebaking was performed at 120 ° C. for 6 minutes. Furthermore, pattern exposure (exposure amount: 14 J / cm ² ) of the ink flow path pattern was performed with a Deep UV exposure machine (trade name: “UX-3000”, manufactured by USHIO INC.). Then, it developed with methyl isobutyl ketone and rinsed with isopropyl alcohol (IPA). Thus, the liquid flow path mold 3 was formed (FIG. 2B). The film thickness of the liquid flow path mold 3 was 15 μm. In this example, an 8-inch silicon substrate having a <100> crystal orientation was used as the substrate 1.
Next, a photosensitive resin having the following composition is applied onto the liquid flow path mold 3 and the substrate 1 by spin coating, and then a heat treatment is performed at 90 ° C. for 3 minutes to form the photosensitive resin that becomes the flow path forming member 4 A layer was formed (FIG. 2 (c)). The film thickness of the photosensitive resin layer on the liquid flow path mold 3 was 10 μm.
Photosensitive resin composition Epoxy resin: Daicel EHPE-3150 (trade name) 100 parts by weight Photopolymerization initiator: ADEKA SP-172 (trade name) 6 parts by weight Adhesion improver: Momentive Performance Materials A-187 5 Part by weight Swelling inhibitor: Central Glass, 1,4-bis (hexafluoro-2-hydroxy-2-propyl) benzene (1,4-HFAB) 20 parts by weight Solvent: Xylene 70 parts by weight Next, i-line stepper exposure Machine (Canon, i5) is used to expose the photosensitive resin layer 5 through a mask (not shown) (exposure amount: 0.35 J / m ² ), and post-exposure baking (PEB) at 90 ° C. For 4 minutes. Further, development with methyl isobutyl ketone and rinsing with IPA were carried out to cure the photosensitive resin layer to form a flow path forming member 4 to form a discharge port 5 (FIG. 2 (d)). When the dynamic contact angle with pure water of the discharge port surface 7 thus formed was measured, the contact angle was 55 °.

In the present embodiment, the hydrophilic treatment was performed simultaneously with the formation of the ink supply path.
After the discharge port 5 is formed, an etching mask 6 is formed on the back side of the substrate on which the ink supply path is formed (FIG. 2E). Polyether amide was used as the material for the etching mask 6. The ink supply path 9 is etched in a state where the alkaline aqueous solution 8 which is an etching solution is in direct contact with the discharge port surface 7 without a protective film or the like on the discharge port surface side. As conditions, it is immersed in a 20% tetramethylammonium hydroxide aqueous solution controlled at a temperature of 80 ° C. and held for 15 hours. As a result, the ink supply path 9 penetrating the substrate 1 was formed, and at the same time, the discharge port surface 7 was made hydrophilic (FIG. 2F). Thereafter, the etching mask 6 was removed (FIG. 2G), and the mold 3 was removed to form the liquid flow path 10 (FIG. 2H).

-Evaluation The measurement of the dynamic contact angle by the pure water of the discharge port surface 7 of the completed inkjet head was measured using DropMeasure-800STD (brand name) by a micro jet company. In addition, the film state such as dissolution, breakage, and peeling of the flow path forming member was visually observed. Furthermore, the completed ink jet head was mounted on a commercially available ink jet recording apparatus (MG6230 (trade name) manufactured by Canon Inc.) for printing, and printing was confirmed and whether or not liquid droplets were not ejected was confirmed. The evaluation criteria are as follows. The results are shown in Table 1.

Evaluation criteria Hydrophilic evaluation A: Dynamic contact angle in pure water less than 15 ° B: Dynamic contact angle in pure water 15 ° or more and less than 25 ° C: Dynamic contact angle in pure water 25 ° or more Film state evaluation A: Dissolution, breakage, no peeling B: Minor dissolution, breakage, peeling C: Not slight dissolution, breakage, peeling Printing evaluation A: No twist, no discharge C: Twist, or no discharge

(Example 2)
In this example, the hydrophilization treatment was performed after the discharge port formation (FIG. 2D).
Similar to the first embodiment, after forming the discharge port 5, an etching mask 6 is formed on the back surface of the substrate (FIG. 2E). Polyether amide was used as the material for the etching mask 6. Then, it was immersed in 40% potassium hydroxide aqueous solution (alkaline aqueous solution 8) controlled at a temperature of 80 ° C. and held for 1 hour. Thereafter, washing with water was performed to complete the hydrophilic treatment (FIG. 3A). The back surface of the substrate 1 is slightly etched to form a part 11 of the ink supply path. Next, in order to form the ink supply path 9, in the present embodiment, it was performed by sandblasting in which an abrasive having a particle diameter of about 10 μm was blown with high-pressure air (FIG. 3B). Further, a protective film 12 for protecting the discharge port surface 7 was used. For the protective film 12, cyclized rubber was used.
The completed inkjet head was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 3
-Hydrophilization treatment of the discharge port surface In this example, the hydrophilic treatment was performed after the discharge port formation (FIG. 2D).
Similar to the first embodiment, after forming the discharge port 5, an etching mask 6 is formed on the back surface of the substrate (FIG. 2E). Polyether amide was used as the material for the etching mask 6. Then, it was immersed in 40% sodium hydroxide aqueous solution (alkaline aqueous solution 8) controlled at a temperature of 80 ° C. and held for 1 hour. Thereafter, washing with water was performed to complete the hydrophilic treatment (FIG. 3A). The back surface of the substrate is slightly etched to form a part 11 of the ink supply path. In the present embodiment, the ink supply path forming process, which is the next process, was formed by a dry etching process using a Bosch process using SF ₆ gas and C ₄ F ₈ gas alternately. Further, a protective film 12 for the discharge port surface for protecting the discharge port surface was used. For the protective film 12, cyclized rubber was used.
The completed inkjet head was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 4
An ink jet head was formed in the same manner as in Example 2 except that the hydrophilic treatment time of the discharge port surface 7 was changed to 30 minutes.
The completed inkjet head was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 5)
An inkjet head was formed in the same manner as in Example 2 except that the hydrophilization treatment of the discharge port surface 7 was immersed in a 60% aqueous potassium hydroxide solution controlled at a temperature of 40 ° C. and held for 24 hours.
The completed inkjet head was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 6)
An inkjet head was formed in the same manner as in Example 2 except that the hydrophilization treatment of the discharge port surface 7 was immersed in a 60% aqueous potassium hydroxide solution controlled at a temperature of 80 ° C. and held for 3 hours.
The completed inkjet head was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 7)
An inkjet head was formed in the same manner as in Example 2 except that the hydrophilization treatment of the discharge port surface 7 was immersed in a 5% tetramethylammonium hydroxide aqueous solution controlled at a temperature of 90 ° C. and held for 3 hours. did.
The completed inkjet head was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 8)
An inkjet head was formed in the same manner as in Example 2 except that the hydrophilization treatment of the discharge port surface 7 was immersed in a 60% aqueous potassium hydroxide solution controlled at a temperature of 25 ° C. and held for 48 hours.
The completed inkjet head was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 9
After the steps up to the etching mask 6 in FIG. 2E are performed in the same manner as in the first embodiment, as shown in FIG. 4A, the region for forming the ink supply path is formed on the substrate using the UV-YAG laser 13. The part 11 of the ink supply path was processed until the remaining thickness became 50 to 400 μm. Thereafter, as shown in FIG. 4B, the remaining portion of the ink supply path 9 was etched while the alkaline aqueous solution 8 was in direct contact with the discharge port surface 7 without a protective film or the like on the discharge port surface side. . As conditions, it was immersed in a 20% tetramethylammonium hydroxide aqueous solution controlled at a temperature of 80 ° C. and held for 1 hour. Thereby, the ink supply path 9 penetrating the substrate 1 was formed, and at the same time, the discharge port surface 7 was made hydrophilic.
The completed inkjet head was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
An inkjet head was formed in the same manner as in Example 1 except that the hydrophilization treatment of the discharge port surface 7 was immersed in an 85% aqueous potassium hydroxide solution controlled at a temperature of 80 ° C. and held for 24 hours.
The completed inkjet head was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)
An inkjet head was formed in the same manner as in Example 2 except that the hydrophilization treatment of the discharge port surface 7 was immersed in a 20% tetramethylammonium hydroxide aqueous solution controlled at a temperature of 60 ° C. and held for 10 minutes. did.
The completed inkjet head was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 3)
An inkjet head was formed in the same manner as in Example 2 except that the hydrophilization treatment of the discharge port surface 7 was immersed in a 3% tetramethylammonium hydroxide aqueous solution controlled at a temperature of 60 ° C. and held for 10 hours. did.
The completed inkjet head was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 4)
An inkjet head was formed in the same manner as in Example 1 except that the hydrophilization treatment of the discharge port surface 7 was immersed in a 40% aqueous potassium hydroxide solution controlled at a temperature of 100 ° C. and held for 8 hours.
The completed inkjet head was evaluated in the same manner as in Example 1. The results are shown in Table 1.

  According to the manufacturing method of the liquid discharge head shown in Examples 1 to 9, good results were obtained. On the other hand, as shown in Comparative Examples 1 to 4, when the temperature of the alkaline aqueous solution was high or the contact time was short, the results of hydrophilicity, film state, printing, etc. were not good.

1. Substrate 2. 2. Discharge energy generating unit 3. Liquid flow path mold 4. flow path forming member 5. Discharge port Etching mask 7. Discharge port surface 8. 8. Alkaline aqueous solution Liquid supply path (ink supply path)
10. Liquid channel (ink channel)
11. Part of liquid supply path 12. Protective film 13. Laser light

Claims (9)

Forming a flow path forming member provided with a discharge port on the first surface of the silicon substrate, the discharge port surface being the discharge port forming surface formed of a resin material containing an epoxy resin;
A hydrophilization treatment step in which an alkaline aqueous solution is brought into contact with a discharge port surface, which is a formation surface of the discharge port, at a temperature of 90 ° C. or lower for 30 minutes or more;
And the alkaline aqueous solution contains at least one of tetramethylammonium hydride, sodium hydroxide, and potassium hydroxide as an alkaline compound, and the alkaline aqueous solution contains 5% by mass to 60% by mass of the alkaline compound. A method of manufacturing a liquid discharge head.   A mask for forming a liquid supply path is formed on the second surface opposite to the first surface of the silicon substrate on which the flow path forming member is formed, and then the alkaline aqueous solution is opened in the mask in the hydrophilic treatment step. The method of manufacturing a liquid ejection head according to claim 1, wherein the liquid ejection head is brought into contact with the second surface of the portion.   The method of manufacturing a liquid ejection head according to claim 2, wherein a liquid supply path that penetrates the silicon substrate is formed by the hydrophilic treatment process.   The method of manufacturing a liquid ejection head according to claim 3, further comprising a step of forming a part of the liquid supply path before the hydrophilization treatment step.   The method of manufacturing a liquid ejection head according to claim 2, wherein the hydrophilization treatment step includes a step of forming a part of the liquid supply path and then forming the rest of the liquid supply path.   A step of forming a protective film that protects the discharge port surface, which is the formation surface of the discharge port subjected to the hydrophilic treatment, after the hydrophilic treatment step and before the step of forming the rest of the liquid supply path. A method for manufacturing a liquid discharge head according to claim 5.   The method of manufacturing a liquid discharge head according to claim 1, wherein the aqueous alkali solution is contacted for 1 hour or longer in the hydrophilization treatment.   The method of manufacturing a liquid discharge head according to claim 1, wherein the alkaline aqueous solution is 30 ° C. or higher and 80 ° C. or lower in the hydrophilization treatment.   The method of manufacturing a liquid discharge head according to claim 1, wherein the alkaline aqueous solution contains 10% by mass or more of the alkaline compound in the hydrophilization treatment.

Images