JP5553538B2 - Method for manufacturing liquid discharge head - Google Patents

Description

  The present invention relates to a method for manufacturing a liquid discharge head that discharges liquid, and more specifically, to a method for manufacturing an ink jet recording head that performs recording by discharging ink onto a recording medium.

  As an example of using a liquid discharge head that discharges liquid, there is an ink jet recording system that performs recording by discharging ink onto a recording medium.

  An ink jet recording head applied to an ink jet recording method (liquid jet recording method) generally generates energy used for discharging a fine discharge port, a liquid flow path, and a liquid provided in a part of the liquid flow path. A plurality of energy generating elements are provided. Conventionally, as a method for producing such an ink jet recording head, for example, Patent Document 1 describes.

  First, a pattern, which is a mold material for an ink flow path, is formed of a soluble resin on a substrate on which an energy generating element is formed. Next, a coating resin layer containing an epoxy resin and a photocationic polymerization initiator serving as an ink flow path wall is formed on the flow path pattern, and a discharge port is formed on the energy generating element by photolithography. Finally, the soluble resin is eluted to cure the coating resin layer that becomes the ink flow path wall.

  In such a manufacturing method, although there is a certain limit to the patterning accuracy of the mold material in the materials used from the present state, a good flow path wall can be formed up to the conventional nozzle density (600 dpi). FIG. 4 is a cross-sectional view for explaining the prior art. As shown in FIG. 4A, the flow path wall 14 is well formed together with the adhesion improving layer 13 on the substrate 11 provided with the energy generating element 12. In addition, the aspect ratio (ratio of height and width) of the flow path wall 14 is 4: 3. On the other hand, when the nozzle density is increased to 1200 dpi, the resolution of the flow path mold made of a photosensitive material is insufficient, and the problem that the flow path wall 14 cannot be formed satisfactorily occurs. For example, if a gap is formed between the end of the flow path wall 14 and the adhesion improving layer 13 as shown in FIG. 4B, the flow paths 16 communicate with each other and are affected by crosstalk. Ink may not be discharged well from the discharge port 15. Further, even if no gap is generated, the reduction in the contact area between the flow path wall and the adhesion improving layer 3 may cause a decrease in reliability due to weak bonding between the flow path wall and the substrate.

  In order to solve the above, it is conceivable to reduce the thickness of the mold material. However, when the nozzle density is increased to 1200 dpi, the flow path width of each flow path is reduced, and ink refill shortage to the nozzles easily occurs. Therefore, in order to secure the channel cross-sectional area of each channel and compensate for such insufficient refill, it is necessary to increase the height of each channel. Therefore, it is practically difficult to reduce the thickness of the channel material. Therefore, it is practically difficult to solve the problem that occurs when the nozzle density is improved by reducing the thickness of the mold material.

JP-A-6-286149

  Accordingly, it is an object of the present invention to provide a method for manufacturing a liquid discharge head in which the above-described problems in the prior art are solved and the bonding strength between the flow path wall and the substrate is improved.

An example of the present invention is a method for manufacturing a liquid discharge head including a flow path wall member having a liquid flow path wall communicating with a discharge port that discharges liquid. In the method for manufacturing a liquid discharge head, polymethylisopropenyl ketone, methacrylic acid, and methacrylate a copolymer of a mixture comprising the steps of providing a layer on a substrate comprising of the layer containing the mixture, followed by development after the exposure with light only wavelengths above 250 nm, from the layer A step of forming a mold of the flow channel, a step of providing a layer to be the flow channel wall member on the substrate so as to cover the mold, and a step of forming the flow channel by removing the mold , have a, the mixture, the polymethyl by weight of the sum of isopropenyl ketone and said copolymer, wherein the polymethyl isopropenyl keto in a proportion of 50 wt% or more 70% by weight or less A method for manufacturing a liquid discharge head, comprising:

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the liquid discharge head with which the joining strength of a flow-path wall and a board | substrate was aimed at. In addition, it is possible to manufacture such a liquid discharge head without extensive modification of the manufacturing process.

It is a typical sectional view showing an example of a manufacturing method of a liquid discharge head of the present invention. It is a schematic diagram which shows an example of the liquid discharge head of this invention. It is a schematic diagram which shows a part of example of the liquid discharge head of this invention. It is a figure for demonstrating a prior art.

  Hereinafter, the present invention will be described in more detail with reference to the drawings.

  The liquid discharge 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 liquid discharge head, recording can be performed on various recording media such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, and ceramics. Note that “recording” used in the present specification not only applies an image having a meaning such as a character or a figure to a recording medium but also an image having no meaning such as a pattern. I mean.

  FIG. 2 is a schematic diagram illustrating a liquid discharge head according to an embodiment of the present invention. The liquid discharge head according to this embodiment includes a Si substrate 1 on which energy generating elements 2 that generate energy used for discharging a liquid are formed in two rows at a predetermined pitch. In the substrate 1, a supply port 8 formed by anisotropic etching of Si is opened between two rows of energy generating elements 2. On the substrate 1, a flow path wall member 5 having a flow path wall is provided with a discharge port 6 provided at a position facing each energy generating element 2 and an individual communication from the supply port 8 to each discharge port 6. A flow path is formed. The position of the discharge port 6 is not limited to the position facing the energy generating element 2.

  This liquid discharge head is arranged so that the surface on which the discharge ports 6 are formed faces the recording surface of the recording medium. In the liquid discharge head, the energy generating element 2 generated by the energy generating element 2 is used for the ink filled in the flow path via the supply port 8, and ink droplets are discharged from the discharge port 6. Is recorded on the recording medium. Examples of the energy generating element 2 include an electrothermal conversion element (so-called heater) as thermal energy and a piezoelectric element as mechanical energy, but are not limited thereto.

  A method for manufacturing the liquid discharge head according to the embodiment of the present invention will be described below. In the following description, the same number is given to the configuration having the same function in the drawings, and the description may be omitted.

  FIG. 3 is a plan perspective view showing an embodiment of the liquid discharge head of the present invention. The form shown in FIG. 3 corresponds to the discharge port 6 corresponding to the energy generating element 2a at a position relatively close to the supply port on one side of the supply port 8 and the energy generating element 2b at a relatively far position. The discharge ports 7 are arranged in a zigzag pattern.

  FIG. 1F is a schematic cross-sectional view showing an example of a method for manufacturing a liquid ejection head according to an embodiment of the invention, and is a cross-sectional view along B-B ′ in FIG. 3. In the perspective view of FIG. 2, it is a cross section corresponding to the A-A ′ direction, although not in a staggered arrangement. Hereinafter, an example of the manufacturing method of the liquid discharge head of the present invention will be described with reference to FIG.

  As shown in FIG. 1A, an adhesion improving layer 3 made of polyetheramide is formed on a Si wafer substrate 1 on which a plurality of electrothermal conversion elements 2 are arranged.

  Subsequently, as shown in FIG. 1B, a film obtained by dissolving a positive photosensitive resin composition in a suitable solvent at a position where a flow path is formed is formed by spin coating to a thickness of 10 μm to 25 μm. To do. As described above, the layer 4a of the positive photosensitive resin composition is provided.

  The positive photosensitive resin composition applicable to the present invention can be patterned by irradiating with ionizing radiation and ultraviolet rays because the main chain decomposition type molecular decay reaction of the positive photosensitive resin proceeds. In addition, the resin composition after patterning undergoes a main chain decomposition-type molecular decay reaction upon irradiation with ionizing radiation and becomes a low-molecular compound, so that it can be easily dissolved and removed.

  An example of a positive photosensitive resin composition applicable to the present invention includes a composition containing a mixture of polymethylisopropenyl ketone and a polymethacrylate resin that is a copolymer of methacrylic acid and methacrylate. . The pattern shape is obtained by mixing a positive photosensitive resin having a carbonyl group, such as polymethylisopropenyl ketone, which has sensitivity and absorption at a wavelength of 250 nm or more, and a polymethacrylate resin that is highly permeable to the same wavelength. Can be verticalized. The polymethacrylate resin is preferably contained in a proportion of 15 to 50% by weight with respect to the total weight of the polymethacrylate resin and the polymethylisopropenyl ketone. The said value is suitable in order to maintain a sensitivity, raising the transmittance | permeability of the photosensitive resin composition with respect to the light used for exposure. Also, acrylic acid having a similar structure as an alternative to the methacrylic acid, and acrylate having a similar structure as an alternative to the metallate can be applied to the present invention.

A preferred specific example of the polymethacrylate resin is a methacrylic copolymer containing methacrylic acid ester (MMA) as a main component and methacrylic acid (MAA). Methacrylic acid based on the sum of methacrylic acid esters and methacrylic acid be used in an amount of 2 to 30% by weight have better this. The molecular weight of the copolymer is preferably 10,000 or more and 50,000 or less. The reason is that a certain amount of the methacrylic acid ester is necessary from the viewpoint of solvent resistance, while methacrylic acid is preferably contained in an amount of 2% or more from the viewpoint of improving sensitivity. The molecular weight of the copolymer is preferably 50000 or less in order to maintain sensitivity, and preferably 10,000 or more in order to maintain solvent resistance. As for the pattern surface shape after development, when considering the dissolution rate in the developer, the ratio of MMA to MAA for forming PMMA is about 20% by weight or less with respect to the sum of MMA and MAA. It is preferable to be used at a ratio of Since MAA exhibits relatively solvent affinity, it is preferable that the MAA is 20% by weight or less so as to suppress the dissolution rate in the developer to some extent.

Next, as shown in FIG. 1C, patterning is performed by exposing the layer 4a of the positive photosensitive resin composition using continuous light having a wavelength of 250 nm or more, and performing development. Although it is the exposure amount at this time, 8-15 J / cm < ² > is preferable. In this way, the flow path pattern 4 which is a flow path mold is formed. The layer 4a of the positive photosensitive resin composition applied to the present invention has improved transmittance with respect to light having a wavelength of 250 nm or more, as compared with the polymethylisopropenyl ketone alone. For this reason, the light used for exposure is less likely to be attenuated in the process from the surface of the layer to the bottom, and the trailing edge of the pattern is suppressed. Therefore, θ in FIG. 1C is large (where θ ≦ 90 °), and a pattern with high perpendicularity is obtained. The exposure is preferably performed using light of only 250 nm or more, but may contain light having a smaller wavelength of 250 nm as long as the exposure is small.

  Thereafter, as shown in FIG. 1 (d), a flow path forming member 5a made of an epoxy resin composition and serving as a flow path wall member for forming a flow path wall is formed.

  Next, as shown in FIG. 1E, after performing exposure using a mask pattern (not shown), development is performed to form the discharge ports 6 in the flow path forming member 5a.

  Next, after forming the protective film forming material by spin coating, the protective film forming material is dried at 80 ° C. to 120 ° C. to form an etching protective film (not shown), and the supply port 8 (not shown) is formed.

  Next, in order to remove the flow path pattern 4 and sufficiently cure the epoxy resin that is the flow path forming member, heating is performed at 200 ° C. for 1 hour to form the flow path wall member 5, and the liquid discharge head is Can be obtained.

  Thereafter, necessary electrical connections are made and the device is mounted.

(Example)
Next, the present invention will be described in more detail with reference to examples and comparative examples.

  A positive photosensitive resin composition was prepared at the following blending ratio to prepare a liquid discharge head. Coating liquid for forming the flow path wall, verticality of the flow path pattern that is the flow path mold, developability (dissolution removal property) of the positive photosensitive resin composition, and liquid discharge head and its manufacturing process The shape maintainability (solvent resistance) of the flow path pattern when applied was evaluated.

Example 1
A polyetheramide layer was formed on the Si wafer substrate 1 on which a plurality of electrothermal conversion elements 2 were arranged, heated at 100 ° C. for 30 minutes, and then heated at 250 ° C. for 1 hour. Thus, the coating solvent was evaporated to form a 2.0 μm thick layer. Then, a resist was applied on the polyetheramide layer and patterned, and the polyetheramide layer was patterned by O ₂ ashing. Thereafter, the resist used as a mask was peeled off to form an adhesion improving layer 3 made of polyetheramide (FIG. 1A).

  A copolymer (PMMA) obtained from a weight ratio of methyl methacrylate (MMA): methacrylic acid (MAA) = 80: 20 was prepared. Each was dissolved in a cyclohexanone solvent such that polymethylisopropenyl ketone (PMIPK (ODUR manufactured by Tokyo Ohka Kogyo Co., Ltd.): copolymer (PMMA (weight average molecular weight = about 30000))) = 80:20 by weight ratio. The partial concentration was 20 wt%, and a solution type positive photosensitive resin composition was obtained.

  Next, the positive photosensitive resin composition was formed on a substrate by spin coating, and baked at 120 ° C. for 6 minutes to a thickness of 15 μm (FIG. 1B).

Next, using an exposure apparatus UX3000 (trade name) manufactured by Ushio Electric Co., Ltd., the light was exposed at an exposure amount of 11 J / cm ² using continuous light having a wavelength of 250 nm or more, and developed with methyl isobutyl ketone. Thereafter, rinsing with isopropyl alcohol was performed to form a flow path pattern 4 (FIG. 1C).

  In order to confirm the shape of the flow path pattern 4 thus produced, the cross-sectional shape was observed with an SEM (Electronic Scanning Microscope) to confirm the perpendicularity of the pattern. Further, it was confirmed by a microscope whether there was any residue of the positive photosensitive resin composition in the developing part. As a result, the pattern wall θ (FIG. 1C) stood at 85 ° or more, and no residue was observed.

  Next, a flow path forming member 5 containing an epoxy resin composition was formed on the substrate so as to cover the flow path pattern (FIG. 1D). Then, the flow path forming member 5 is exposed using a mask pattern (not shown) with a mask aligner MPA-600 (trade name) manufactured by Canon Inc., then developed, and the flow path forming member 5 is developed. The discharge port 6 was formed in (Fig. 1 (e)). This epoxy resin composition consists of epoxy resin = 100 parts by weight, cationic polymerization initiator = 2 parts by weight, additive = 5 parts by weight, the flow path forming member is a solution containing this composition, and the solvent is xylene. is there.

  The epoxy resin used is EHPE3150 (trade name) manufactured by Daicel Chemical Industries, Ltd., SP-172 (trade name) manufactured by Adeka Co., Ltd. is used as a cationic polymerization initiator, and SILQUEST A-187 manufactured by Nissho Corporation is used as an additive. (Trade name) was used.

  Then, after forming the protective film forming material by spin coating, the protective film forming material was dried at 80 ° C. to 120 ° C. to form an etching protective film (not shown). Thereafter, a supply port 8 was formed (not shown).

  Next, the flow path pattern 4 made of a positive photosensitive resin composition was subjected to front exposure using light of 200 to 330 nm to solubilize the flow path pattern 4. Subsequently, the film was immersed in methyl lactate while applying ultrasonic waves to dissolve and remove the flow path pattern 4.

  Further, in order to sufficiently cure the epoxy resin 5 which is a flow path forming member, heating was performed at 200 ° C. for 1 hour to obtain a flow path wall member to obtain a liquid discharge head (FIG. 1F).

  Thus, about the produced liquid discharge head, the flow-path shape was observed with the microscope. Since the channel wall member used in this embodiment is colorless and transparent, the shape of the channel can be observed through the channel wall member. As a result, the shape of the ink flow path was sharp and no distortion or the like was observed. Furthermore, when mounted on a recording apparatus and printed using ink, stable and good printing was possible.

(Example 2)
The difference from Example 1 is that the solution-type positive photosensitive resin composition was polymethylisopropenyl ketone (PMIPK): copolymer (PMMA) = 70: 30 in weight ratio. Other than that was carried out in the same manner as in Example 1.

(Example 3)
The difference from Example 1 is that the polymethylisopropenyl ketone (PMIPK): copolymer (PMMA) = 60: 40 by weight ratio of the solution type positive photosensitive resin composition. Other than that was carried out in the same manner as in Example 1.

(Example 4)
The difference from Example 1 is that the polymethylisopropenyl ketone (PMIPK): copolymer (PMMA) = 50: 50 in weight ratio with respect to the solution type positive photosensitive resin composition. Other than that was carried out in the same manner as in Example 1.

(Example 5)
The differences from the first embodiment are the following two points. Other than that was carried out in the same manner as in Example 1. About the solution type positive photosensitive resin composition, the composition ratio of the copolymer (PMMA) was methyl methacrylate (MMA): methacrylic acid (MAA) = 95: 5 by weight ratio. Further, polymethylisopropenyl ketone (PMIPK): copolymer (PMMA) = 70: 30.

(Example 6)
The differences from the first embodiment are the following two points. Other than that was carried out in the same manner as in Example 1. About the solution type positive photosensitive resin composition, the composition ratio of the copolymer (PMMA) was methyl methacrylate (MMA): methacrylic acid (MAA) = 90: 10 by weight ratio. Further, polymethylisopropenyl ketone (PMIPK): copolymer (PMMA) = 70: 30.

(Example 7)
The differences from the first embodiment are the following two points. Other than that was carried out in the same manner as in Example 1. About the solution-type positive photosensitive resin composition, the composition ratio of the copolymer (PMMA) was methyl methacrylate (MMA): methacrylic acid (MAA) = 70: 30 by weight ratio. Further, polymethylisopropenyl ketone (PMIPK): copolymer (PMMA) = 70: 30.

(Example 8)
The differences from the first embodiment are the following two points. Other than that was carried out in the same manner as in Example 1. About the solution type positive photosensitive resin composition, the composition ratio of the copolymer (PMMA) was methyl methacrylate (MMA): methacrylic acid (MAA) = 90: 10 by weight ratio. Further, polymethylisopropenyl ketone (PMIPK): copolymer (PMMA) = 50: 50.

Example 9
The differences from the first embodiment are the following two points. Other than that was carried out in the same manner as in Example 1. About the solution-type positive photosensitive resin composition, the composition ratio of the copolymer (PMMA) was methyl methacrylate (MMA): methacrylic acid (MAA) = 70: 30 by weight ratio. Further, polymethylisopropenyl ketone (PMIPK): copolymer (PMMA) = 50: 50.

(Comparative example)
The difference from Example 1 was that only the polymethylisopropenyl ketone was used for the solution-like positive photosensitive resin composition without mixing the copolymer (PMMA). Other than that was carried out in the same manner as in Example 1.

  The cross-sectional shape of the flow path pattern was observed with an SEM (Electronic Scanning Microscope) to confirm the shape of the pattern. Further, it was confirmed by a microscope whether there was any residue of the positive photosensitive resin composition in the developing part. As a result, no residue was observed, but the pattern wall was less than 85 ° and the pattern was trapezoidal.

  When the flow path shape of the liquid discharge head was observed, the flow path shape was fine and the shape was not broken.

  The results of evaluating the above examples and comparative examples are shown in Table 1, and the evaluation criteria are described below.

(Evaluation criteria)
Verticality: Bottom angle θ of flow path pattern (angle formed by side wall pattern side and substrate)
Evaluation with.
Δ: θ <85 °
○: 85 ° ≦ θ <90 °
A: θ ≒ 90 °
Developability: Evaluated by observing the appearance of the flow path pattern.
○: Some irregularities may be seen on the pattern surface, but there is no residue on the substrate.
A: There are no irregularities on the pattern surface, and there is no residue on the substrate.

  Regarding the shape of the channel, all the examples and the comparative examples are good, and it is considered that the shape of the channel pattern did not collapse even when the channel forming member was covered.

  From the perpendicularity evaluation results shown in Table 1, it can be seen that PMIPK is preferably 50 weight percent or more and 70 weight percent or less with respect to the sum of PMIPK and PMMA.

  Further, from the evaluation results of developability, it can be seen that the MAA is preferably used at a ratio of 20 weight percent or less with respect to the sum of MMA and MAA with respect to the ratio of MMA and MAA for forming PMMA. As for Examples 2 and 6, the development speed is appropriately compared with Example 7 in which the concentration of MAA is 20 weight percent or less, the same concentration is 30 weight percent, and the ratio of PMIPK to PMMA is the same. It is considered that good developability is obtained. In Example 6, the ratio of MMA and MAA is the same as in Example 8, but the ratio of PMMA is small, the solubility in a solvent is appropriately increased, and the developability is considered to be particularly good. .

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Energy generating element 3 Adhesion improvement layer 4 Type | mold 5 Channel wall member 6 Discharge port

Claims (5)

In a method of manufacturing a liquid discharge head including a flow path wall member having a liquid flow path wall communicating with a discharge port for discharging liquid,
A polymethyl isopropenyl ketone, comprising the steps of a copolymer of methacrylic acid and methacrylate, a layer comprising a mixture of providing on a substrate,
The layer containing the mixture, followed by development after the exposure with light only wavelengths above 250 nm, and forming a mold of the flow path from said layer,
Providing a layer to be the flow path wall member on the substrate so as to cover the mold;
Removing the mold to form the flow path;
Have a said mixture, said the weight of the sum of polymethyl isopropenyl ketone and the copolymer may include the said polymethyl isopropenyl ketone in a ratio of 50 wt% or more 70% by weight or less A method for manufacturing a liquid discharge head. The copolymer is formed by using the methacrylic acid at a ratio of 20 weight percent or less with respect to the sum of the weight of the methacrylic acid and the weight of the methacrylate. 2. A method for manufacturing a liquid discharge head according to 1 . The thickness of the mold, the method for manufacturing a liquid discharge head according to claim 1 or 2, characterized in that at 10μm or 25μm or less. Method for manufacturing a liquid discharge head according to any one of claims 1 to 3, characterized in that the molecular weight of the copolymer of 10,000 to 50,000. The copolymer includes the copolymer in a ratio of 15 weight percent to 50 weight percent with respect to a total weight of the polymethylisopropenyl ketone and the copolymer. 5. A method for manufacturing a liquid discharge head according to any one of items 1 to 4.