Recording element substrate and method for manufacturing the same

Abstract

To provide a recording element substrate which can both ensure visibility of individual identification information and ensure a reduction in a size, and a manufacturing process thereof.SOLUTION: A recording element substrate 11 includes a substrate 1 and a flow passage forming member 6 having a flow passage 4 for supplying a liquid to a discharge port 3. In the flow passage forming member 6, a cavity part 7 which does not communicate with the flow passage 4 is formed, and a side surface of the cavity part 7 is formed to be almost perpendicular to the substrate. Between the cavity part 7 and the substrate 1, a base film 8 is formed. A refraction index of the flow passage forming member 6 is smaller than a refraction index of the base film 8, and a difference between the refraction index of the flow passage forming member 6 and the refraction index of the base film 8 is 0.3 or more.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a recording element substrate and a method for manufacturing the same.

Background Art

[0002] A liquid ejection head that ejects a liquid onto a recording medium such as printing paper to perform recording is known. The liquid ejection head is provided with a recording element substrate having a liquid ejection port for ejecting a liquid, an energy generating element for generating energy for ejection, and the like. From the viewpoint of process management, such a recording element substrate may be provided with individual identification information.

[0003] Patent Document 1 discloses a method for imparting individual identification information to a recording element substrate. A method is adopted in which a hollow portion is provided in a flow path forming member that forms a flow path on the recording element substrate, and the shape of the hollow portion (hollow portion pattern) is made, for example, a number to impart individual identification information. Further, in Patent Document 1, the visibility of the individual identification information is also improved by inclining the side surface of the hollow portion with respect to the substrate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the method of Patent Document 1, since the side surface of the hollow portion is inclined with respect to the substrate, it is difficult to miniaturize the recording element substrate. This is because, in order to incline the side surface of the hollow portion, an extra space corresponding to the inclination of the side surface is required between a part of the adjacent individual identification information, making it difficult to densify the hollow portion pattern.

[0006] In view of the above problems, the present invention aims to provide a recording element substrate and a manufacturing process thereof that can achieve both visibility of individual identification information and miniaturization. [Means for solving the problem]

[0007] To solve the above problems, the present invention provides a recording element substrate comprising a substrate having an energy generating element that generates energy for discharging liquid from a discharge port, and a channel forming member having a channel for supplying liquid to the discharge port, wherein the channel forming member has a cavity that is not in communication with the channel, the side surface of the cavity is formed substantially perpendicular to the substrate, a base film is formed between the cavity and the substrate, the refractive index of the channel forming member is smaller than the refractive index of the base film, and the difference between the refractive index of the channel forming member and the refractive index of the base film is 0.3 or more. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a recording element substrate and a manufacturing process thereof that can achieve both visibility of individual identification information and miniaturization. [Brief explanation of the drawing]

[0009] [Figure 1] Schematic diagram of the recording element substrate. [Figure 2] Schematic cross-sectional view of a recording element substrate. [Figure 3] Top view of the individual identification information unit. [Figure 4] A schematic cross-sectional diagram showing the manufacturing method of a recording element substrate. [Figure 5] Top view of individual identification information. [Figure 6] A diagram illustrating Fresnel reflection. [Figure 7] Top view of the individual identification information unit. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described in detail below.

[0011] (First embodiment) Figure 1 is a schematic diagram of the recording element substrate 11 of this embodiment. The recording element substrate 11 is a substrate 1 equipped with an energy generating element (not shown) that generates energy for ejection and a liquid supply port 5, and a flow channel forming member 6 having a flow channel 4 and an ejection port 3 is formed on the substrate. The flow channel forming member 6 is equipped with an individual information region 2 having a cavity 7 that is not in communication with the flow channel 4. A liquid-repellent film (not shown) is formed on the surface in the positive Z direction which is the liquid ejection surface.

[0012] Figure 2 is a schematic cross-sectional view of the recording element substrate of this embodiment shown in Figure 1, specifically AA'. As shown in Figure 2, the substrate 1, which is equipped with an energy generating element (not shown), has a channel forming member 6 having an outlet 3 and a channel 4. A liquid supply port 5 is also formed, penetrating from one side to the other of the channel forming member. The channel forming member 6 includes an individual information region 2 having a cavity 7 that is not in communication with the channel 4, and a base film 8 is formed on the substrate side of the cavity 7.

[0013] The visibility of the cavity 7 can be improved by having a higher refractive index in the base film 8 than in the channel forming member 6. Figure 6 is a schematic diagram of Fresnel reflection (normal incidence). As shown in Figure 6, according to the formula for Fresnel reflection when light is incident perpendicularly on an interface where materials with different refractive indices are in contact, it is known that the magnitude of reflection is correlated with the difference in refractive index. In this embodiment, considering the reflection at the two interfaces, the cavity and the base film, and the channel forming member and the base film, it is preferable that the base film has a higher refractive index than the channel forming member. The base film 8 is on the substrate side surrounding the cavity 7 and only needs to be in the region of at least the individual information area 2. Furthermore, it is preferable from the viewpoint of productivity that the base film 8 also serves as a protective film for the substrate. Considering Fresnel reflection, in this invention, it is preferable that the difference between the refractive index of the channel forming member and the refractive index of the base film is 0.3 or more. This increases the amount of reflected light from the base film, improving visibility. Furthermore, it is preferable that the refractive index of the base film is 1.9 or more, as this increases the amount of reflected light from the base film.

[0014] Figure 3 is a schematic top view of the individual information area 2 shown in Figure 2, viewed from the positive Z direction. As shown in Figure 3, the individual information area 2 is positioned so that the cavity 7 is in contact with the end of the flow channel forming member 6. Here, the cavity 7 does not necessarily have to be in contact with the end of the flow channel forming member 6; it is sufficient if there is some connection to the atmosphere (opening to the atmosphere) so that the cavity 7 can be formed later. Also, as an example, the cavity 7 shows individual information by the shape of a number. However, it is not limited to this, and as shown in Figures 7(a) and 7(b), it can be a shape that can be seen from above, such as letters or marks. As an example of individual information, the position within the substrate may be represented by the individual information (Figure 5), but the individual information may also contain process inspection information or measurement information. In addition, in order to make the individual information easier to see by the shape of the cavity 7, the individual information area 2 is provided with a base film (not shown) that has a refractive index greater than that of the flow channel forming member 6. Therefore, the reflectivity at the interface between the cavity 7 and the base film 8, and between the channel forming member 6 and the base film 8, increases, making the shape of the cavity more clearly visible. When reflectivity increases, the amount of reflected light increases, resulting in increased brightness and improved visibility.

[0015] It is preferable that the refractive index of the channel-forming member 6 is smaller than that of the underlying film 8. If the refractive index of the channel-forming member 6 is larger than that of the underlying film 8, light rays entering the channel-forming member from above will be greatly refracted, reducing visibility. To suppress this, it is preferable that the refractive index of the channel-forming member 6 be as small as possible.

[0016] Furthermore, the angle between the side of the cavity and the substrate should ideally be between 85° and 95°. This is because forming the side of the cavity almost perpendicular to the substrate reduces the extra space required between adjacent individual identification information when the side of the cavity is tilted, making it possible to densely pack the cavity pattern.

[0017] Next, a method for manufacturing the recording element substrate of the present embodiment will be described using FIG. 4. As shown in FIG. 4(a), a substrate 1 provided with an underlayer film 8 that also serves as an energy generating element and a substrate protective film is prepared, and a liquid supply port 5 is formed so as to penetrate the substrate. Next, as shown in FIG. 4(b), a first channel forming member 9 made of a negative photosensitive resin is formed on the surface of the substrate 1 where the underlayer film 8 is formed. Next, as shown in FIG. 4(c), the first channel forming member 9 is exposed to i-line through a photomask, thereby optically determining a portion 9A that becomes a channel wall, a portion 9B that becomes a channel, and a cavity portion 9C that does not communicate with the channel. Here, since the first channel forming member is a negative photoresist and is exposed by an i-line stepper exposure method, the channel wall is formed almost vertically by adjusting the exposure focus. Next, as shown in FIG. 4(d), a second channel forming member (discharge port forming member) 10 made of a negative photosensitive resin is formed on the first channel forming member. Next, as shown in FIG. 4(e), the second channel forming member 10 is exposed to i-line through a photomask, thereby optically determining a portion 10A that becomes a channel wall and a portion 10B that becomes a discharge port. Next, as shown in FIG. 4(f), the unexposed portion of the channel forming member 6 is removed using a solvent that can remove the portion shielded by the photomask, thereby forming a channel 4, a discharge port 3, and a cavity portion 7.

[0018] Thereafter, the wafer is divided into chips, and the recording element substrate is completed by mounting the chips on a member for supplying liquid. Here, in the present embodiment, the underlayer film also serves as a protective film for the substrate and is formed over the entire surface of the substrate, but it is not limited to this, and it may be formed at least in the individual information area. Also, although the second channel wall forming member is formed in a state where the first channel wall forming member is optically latent-imaged, only the channel wall portion of the first channel forming member may be formed in advance, and the second channel forming member may be formed thereon.

[0019] (Example) An embodiment of the method for manufacturing a recording element substrate of the present invention will be described with reference to FIG. 4. A plurality of liquid energy generating elements (not shown) were arranged on the substrate 1 shown in FIG. 4(a), and a base film 8 that also serves as an insulating protective film was formed thereon. Then, a mask resist was formed on the base film 8, and after patterning, the substrate 1 was processed by dry etching to form the liquid supply port 5. The substrate 1 was a silicon substrate. After forming SiO and SiN by plasma CVD, SiCN was formed as the base film 8. At this time, the refractive index of the formed base film 8 was 2.4.

[0020] Next, as shown in FIG. 4(b), on the base film 8, a first flow path forming member 9 which is a negative-type photosensitive resin formed in a dry film shape on a support member was used and formed by dry film transfer. Here, the thickness of the first flow path forming member 9 was 10 μm. A VTM-200 (trade name, manufactured by Takatori) was used as the transfer device. As the negative-type photosensitive resin, a mixture of 100 parts by mass of epoxy resin EHPE3150 (trade name, manufactured by Daicel Chemical Industries), 6 parts by mass of a photo cationic polymerization catalyst SP-172 (trade name, manufactured by Asahi Denka Kogyo), and 20 parts by mass of a binder resin jER1007 (trade name, manufactured by Mitsubishi Chemical) was used. As the support member of the dry film resist, a release-treated PET film was used. The transfer temperature was 70 °C and the pressure was 0.5 MPa. The peeling speed of the support member was 5 mm / s.

[0021] Next, as shown in FIG. 4(c), by performing i-line exposure through a photomask, in the first flow path forming member 9, the portion 9A that will later become the flow path wall was exposed with i-line (wavelength 365 nm) using a Canon FPA-5510iV, and then PEB was performed. The exposure amount was 8000 J / m2. PEB was heated on a hot plate at 50 °C for 4 minutes to promote the curing reaction. The portion 9B that becomes the flow path and the cavity portion 9C that does not communicate with the flow path were shielded by the photomask, so the curing reaction did not proceed. The cavity portion 9C was arranged so as to contact the end of the flow path wall. Also, by setting the exposure focus at a position half of the thickness of the first flow path forming member, the side wall of the cavity portion was formed substantially perpendicular to the substrate.

[0022] Next, as shown in Figure 4(d), a second channel forming member (discharge port forming member, second dry film) 10 made of a dry film-like negative-type photosensitive resin was formed on the first channel forming member 9 (on the first dry film) with a thickness of 10 μm. As the negative-type photosensitive resin, a mixture of 100 parts by mass of epoxy resin EHPE3150 (trade name, manufactured by Daicel Chemical Industries) and 3 parts by mass of onium salt, a photocationic polymerization initiator, was used. Here, the onium salt has higher photosensitivity than the photocationic polymerization catalyst SP-172 used in the channel forming member and can generate cations from a low exposure. A PET film treated with a release agent was used as the support member for the dry film resist. The temperature for transferring the discharge port forming member was 40°C and the pressure was 0.3 MPa. The peeling speed of the support member was 5 mm / s. A thickness of 2 μm to 11 μm can be suitably applied to the discharge port forming member.

[0023] Next, as shown in Figure 4(e), the portion of the second channel forming member 10 that will form the channel wall was exposed to i-line light (wavelength 365 nm) using a Canon FPA-5510iV (reduction projection exposure) to optically determine the portion that will form the channel wall 10A and the portion that will form the discharge port 10B. The exposure dose was set to 1000 J / m2. At this point, the unexposed portion of the first channel wall forming member was also irradiated with light, but due to adjustment of the material's photosensitivity, the curing reaction did not occur due to the exposure of the second channel forming member. Subsequently, the PEB was heated on a hot plate at 90°C for 5 minutes to accelerate the curing reaction.

[0024] Next, as shown in Figure 4(f), the unexposed portions of the first channel forming member 9 and the second channel forming member 10 were removed collectively by a developing process to form the channel 4, the discharge port 3, and the cavity 7. Propylene glycol monomethyl acetate was used as the solvent for the unexposed portions. After that, baking was performed at 200°C to complete the epoxy resin reaction. The refractive index of the channel forming member 6 formed at this time was 1.6.

[0025] After the above steps, a substrate for a recording element is completed, which has a nozzle section that discharges liquid from the liquid supply port 5 through the flow path 4 to the discharge port 3, and a cavity section 7 that holds individual information. Then, this substrate is cut and separated into chips using a dicing saw or the like, and after electrical wiring to drive the liquid energy generating element is joined to each chip, a chip tank component for liquid supply is joined to it. This completes the recording element substrate. When the individual information section of this recording element substrate was examined, good visibility was observed even though the side of the cavity section was almost vertical.

[0026] To summarize the above, we have the following conclusions.

[0027] [Configuration 1] A substrate having an energy generating element that generates energy for discharging liquid from a discharge port, A channel forming member having a channel for supplying liquid to the discharge port, In a recording element substrate comprising, The channel forming member has a cavity formed in it that is not in communication with the channel. The side surface of the cavity is formed substantially perpendicular to the substrate. A base film is formed between the cavity and the substrate. The refractive index of the channel forming member is smaller than the refractive index of the underlying film. A recording element substrate characterized in that the difference between the refractive index of the channel forming member and the refractive index of the undercoat film is 0.3 or more.

[0028] [Configuration 2] The recording element substrate according to configuration 1, wherein the angle between the side surface of the cavity and the substrate is 85° to 95°.

[0029] [Configuration 3] The recording element substrate according to configuration 1 or 2, wherein the refractive index of the undercoat film is 1.9 or greater.

[0030] [Structure 4] The recording element substrate according to any one of configurations 1 to 3, wherein the underlayer is a protective film for the substrate.

[0031] [Composition 5] The recording element substrate according to any one of configurations 1 to 4, wherein the cavity is open to the atmosphere.

[0032] [Composition 6] A discharge port forming member is formed on the flow channel forming member, The recording element substrate according to any one of configurations 1 to 5, wherein the thickness of the discharge port forming member is 2 μm to 11 μm.

[0033] [Composition 7] A substrate having an energy generating element that generates energy for discharging liquid from a discharge port, A flow path forming member having a flow path for supplying liquid to the discharge port and a cavity that is not in communication with the flow path, In a method for manufacturing a recording element substrate, A step of preparing a substrate having an undercoat, The step of forming a channel forming member on the substrate, A step of forming the first dry film, which will be the channel forming member, on the substrate, A step of latent imaging the portion of the first dry film that will become the flow path and the portion that will become the cavity, A step of forming a second dry film, which will be the discharge port forming member, on the first dry film, The process of latent imaging the portion of the second dry film that will become the discharge port, A step of developing the first dry film to form the flow channel and the cavity, The process involves developing the second dry film described above to form the discharge port, It has, The aforementioned underlayer film is formed between the substrate and the cavity, The refractive index of the channel forming member is smaller than the refractive index of the underlying film. A method for manufacturing a recording element substrate, characterized in that the difference between the refractive index of the channel forming member and the refractive index of the undercoat film is 0.3 or more.

[0034] [Structure 8] The method for manufacturing a recording element substrate according to configuration 7, wherein the first dry film is a negative-type photosensitive resin.

[0035] [Composition 9] The method for manufacturing a recording element substrate according to configuration 7, wherein the second dry film is a negative-type photosensitive resin.

[0036] [Configuration 10] A method for manufacturing a recording element substrate according to any one of configurations 7 to 9, wherein a reduction projection exposure apparatus is used when developing the first dry film.

[0037] [Composition 11] A method for manufacturing a recording element substrate according to any one of configurations 7 to 10, wherein the second dry film is formed on the first dry film after the first dry film has been formed.

[0038] [Composition 12] A method for manufacturing a recording element substrate according to any one of configurations 7 to 11, wherein the development of the first dry film and the development of the second dry film are performed in a single operation.

[0039] [Composition 13] A method for manufacturing a recording element substrate according to any one of configurations 7 to 12, wherein the cavity is open to the atmosphere.

[0040] [Composition 14] A method for manufacturing a recording element substrate according to any one of configurations 7 to 13, wherein the refractive index of the undercoat is 1.9 or greater.

[0041] [Composition 15] The recording element substrate according to any one of configurations 7 to 14, wherein the underlayer is a protective film for the substrate.

[0042] [Composition 16] The recording element substrate according to any one of configurations 7 to 15, wherein the thickness of the discharge port forming member is 2 μm to 11 μm. [Explanation of symbols]

[0043] 1 circuit board 2. Individual Information Area 3 outlet 4 Flow channels 5 Liquid supply port 6. Flow channel forming member 7 Cavity 8. Primer 11 Recording element substrate

Claims

1. A substrate having an energy generating element that generates energy for discharging liquid from a discharge port, A channel forming member having a channel for supplying liquid to the discharge port, In a recording element substrate comprising, The channel forming member has a cavity formed in it that is not in communication with the channel. The side surface of the cavity is formed substantially perpendicular to the substrate. A base film is formed between the cavity and the substrate. The refractive index of the channel forming member is smaller than the refractive index of the underlying film. A recording element substrate characterized in that the difference between the refractive index of the channel forming member and the refractive index of the undercoat film is 0.3 or more.

2. The recording element substrate according to claim 1, wherein the angle between the side surface of the cavity and the substrate is 85° to 95°.

3. The recording element substrate according to claim 1, wherein the refractive index of the undercoat film is 1.9 or greater.

4. The recording element substrate according to any one of claims 1 to 3, wherein the underlayer film is a protective film for the substrate.

5. The recording element substrate according to any one of claims 1 to 3, wherein the cavity is open to the atmosphere.

6. A discharge port forming member is formed on the flow channel forming member, The recording element substrate according to any one of claims 1 to 3, wherein the thickness of the discharge port forming member is 2 μm to 11 μm.

7. A substrate having an energy generating element that generates energy for discharging liquid from a discharge port, and a base film, A flow path forming member having a flow path for supplying liquid to the discharge port and a cavity that is not in communication with the flow path, A discharge port forming member provided on the flow channel forming member and forming the discharge port, In a method for manufacturing a recording element substrate, The process of preparing the aforementioned substrate, A step of forming the first dry film, which will be the channel forming member, on the substrate, A step of latent imaging the portion of the first dry film that will become the flow path and the portion that will become the cavity, The second dry film, which will serve as the discharge port forming member, is formed on the first dry film. The process of doing so, The process of latent imaging the portion of the second dry film that will become the discharge port, The process involves developing the first dry film to form the channel and the cavity, and using the first dry film as the channel forming member. The process involves developing the second dry film to form the discharge port, and using the second dry film as the discharge port forming member. It has, The aforementioned underlayer film is formed between the substrate and the cavity, The refractive index of the channel forming member is smaller than the refractive index of the underlying film. A method for manufacturing a recording element substrate, characterized in that the difference between the refractive index of the channel forming member and the refractive index of the undercoat film is 0.3 or more.

8. The method for manufacturing a recording element substrate according to claim 7, wherein the first dry film is a negative-type photosensitive resin.

9. The method for manufacturing a recording element substrate according to claim 7, wherein the second dry film is a negative-type photosensitive resin.

10. The method for manufacturing a recording element substrate according to claim 7, wherein a reduction projection exposure apparatus is used when developing the first dry film.

11. A method for manufacturing a recording element substrate according to any one of claims 7 to 10, wherein the second dry film is formed on the first dry film after the first dry film has been formed.

12. A method for manufacturing a recording element substrate according to any one of claims 7 to 10, wherein the development of the first dry film and the development of the second dry film are performed in a single operation.

13. The method for manufacturing a recording element substrate according to any one of claims 7 to 10, wherein the cavity is open to the atmosphere.

14. A method for manufacturing a recording element substrate according to any one of claims 7 to 10, wherein the refractive index of the undercoat is 1.9 or greater.

15. The recording element substrate according to any one of claims 7 to 10, wherein the undercoat is a protective film for the substrate.

16. The recording element substrate according to any one of claims 7 to 10, wherein the thickness of the discharge port forming member is 2 μm to 11 μm.

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