Liquid ejection substrate, liquid ejection head, and method for manufacturing liquid ejection substrate

Abstract

The present disclosure relates to a liquid ejection substrate, a liquid ejection head, and a method for manufacturing a liquid ejection substrate. A liquid ejection substrate configured to eject a liquid includes a flow channel forming substrate having a first surface, a second surface facing a direction opposite to a direction in which the first surface faces, and a flow channel penetrating from the first surface to the second surface and configured to allow the liquid to flow through the flow channel; a first functional layer covering the second surface and an inner peripheral surface of the flow channel; and a second functional layer covering the first functional layer formed on the second surface of the flow channel forming substrate.

Description

Technical Field

[0001] This disclosure relates to a liquid jetting substrate, a liquid jetting head, and a method for manufacturing a liquid jetting substrate. Background Technology

[0002] Japanese Patent Application Publication No. 2019-72882 discloses a liquid jetting head (liquid jetting substrate) comprising a perforated substrate (flow channel forming substrate) having through holes (flow channels). In Japanese Patent Application Publication No. 2019-72882, the perforated substrate has a first surface, a second surface (corresponding to the back surface of the first surface), and the inner wall surface (inner peripheral surface) of the through hole penetrating from the first surface to the second surface covered by a protective film (functional layer). Thus, the liquid jetting head of Japanese Patent Application Publication No. 2019-72882 can prevent resin material contained in the perforated substrate from being eluted into the liquid flowing through the through holes.

[0003] However, in the liquid jet head of Japanese Patent Application Publication No. 2019-72882, there is still room for improvement in the adhesion between the flow channel forming substrate and the functional layer in order to obtain sufficient protective performance in the functional layer. Summary of the Invention

[0004] One object of this disclosure is to provide a liquid jetting substrate that can further improve the adhesion between the flow channel forming substrate and the functional layer.

[0005] A liquid jetting substrate configured to jet liquid includes: a flow channel forming substrate having a first surface, a second surface, and a flow channel, the second surface facing a direction opposite to that of the first surface, the flow channel penetrating from the first surface to the second surface and configured to allow liquid to flow through the flow channel; a first functional layer covering the second surface and the inner peripheral surface of the flow channel; and a second functional layer covering the first functional layer formed on the second surface of the flow channel forming substrate.

[0006] The features of this disclosure will become apparent from the accompanying drawings and the following description of embodiments. The following description of embodiments is by way of example. Attached Figure Description

[0007] Figure 1 A schematic perspective view of the liquid jetting device applicable to the embodiments;

[0008] Figure 2 A diagram illustrating the liquid injection head used to explain the embodiments;

[0009] Figure 3A This is a schematic cross-sectional perspective view of the liquid jetting substrate;

[0010] Figure 3B A schematic cross-sectional view of the liquid jet substrate viewed along the X direction;

[0011] Figure 3C A schematic cross-sectional view of the liquid jetting substrate viewed along the Y direction;

[0012] Figure 3D A schematic plan view of the liquid jetting substrate applicable to the embodiments;

[0013] Figure 4 A diagram illustrating a comparative example of a liquid jet substrate;

[0014] Figure 5A A diagram illustrating an example of the steps in a method for manufacturing a liquid jet substrate;

[0015] Figure 5B A diagram illustrating an example of the steps in a method for manufacturing a liquid jet substrate;

[0016] Figure 5C A diagram illustrating an example of the steps in a method for manufacturing a liquid jet substrate;

[0017] Figure 5D A diagram illustrating an example of the steps in a method for manufacturing a liquid jet substrate;

[0018] Figure 5E A diagram illustrating an example of the steps in a method for manufacturing a liquid jet substrate;

[0019] Figure 5F A diagram illustrating an example of the steps in a method for manufacturing a liquid jet substrate;

[0020] Figure 5G A diagram illustrating an example of the steps in a method for manufacturing a liquid jet substrate;

[0021] Figure 5H A diagram illustrating an example of a liquid jetting substrate;

[0022] Figure 6A This is a schematic cross-sectional view of the liquid jetting substrate in the modified example;

[0023] Figure 6B This is a schematic plan view of the liquid jetting substrate in the modified example;

[0024] Figure 6C This is a schematic cross-sectional view of the liquid jetting substrate in the modified example;

[0025] Figure 6D This is a schematic plan view of the liquid jetting substrate in the modified example;

[0026] Figure 6E This is a schematic cross-sectional view of the liquid jetting substrate in the modified example;

[0027] Figure 6F This is a schematic plan view of the liquid jetting substrate in the modified example;

[0028] Figure 6G This is a schematic cross-sectional view of the liquid jetting substrate in the modified example;

[0029] Figure 6H This is a schematic plan view of the liquid jetting substrate in the modified example;

[0030] Figure 6I This is a schematic cross-sectional view of the liquid jetting substrate in the modified example;

[0031] Figure 6J This is a schematic plan view of the liquid jetting substrate in the modified example;

[0032] Figure 6K This is a schematic cross-sectional view of the liquid jetting substrate in the modified example;

[0033] Figure 6L This is a schematic plan view of the liquid jetting substrate in the modified example;

[0034] Figure 7A This is a schematic cross-sectional view of the liquid jetting substrate in the embodiment;

[0035] Figure 7B This is a schematic cross-sectional view of the liquid jetting substrate in the modified example;

[0036] Figure 7C A schematic cross-sectional view of the liquid jetting substrate in the modified example; and

[0037] Figure 7D This is a schematic cross-sectional view of the liquid jetting substrate in the modified example. Detailed Implementation

[0038] [First Embodiment]

[0039] <Liquid jetting equipment 100>

[0040] Figure 1 This is a schematic perspective view of the liquid jetting device 100 applicable to this embodiment.

[0041] like Figure 1 As shown, the liquid jetting device 100 includes: a one-pass-type liquid jetting head 101 configured to move the printing medium P once and print an image on the printing medium P; and a transport device 102 configured to transport the printing medium P.

[0042] In the liquid ejection head 101, multiple ejection ports 5 are used for ejecting liquids (e.g., ink) (see...). Figure 2 (etc.) are arranged on one side corresponding to the entire width (length in the X direction) of the printing medium P.

[0043] In this embodiment, the liquid ejector head 101 corresponds to four colors: cyan (C), magenta (M), yellow (Y), and black (K). Specifically, the liquid ejector head 101 includes a first liquid ejector head 101Ca and a second liquid ejector head 101Cb corresponding to cyan (C) ink. The liquid ejector head 101 includes a third liquid ejector head 101Ma and a fourth liquid ejector head 101Mb corresponding to magenta (M) ink. The liquid ejector head 101 includes a fifth liquid ejector head 101Ya and a sixth liquid ejector head 101Yb corresponding to yellow (Y) ink. The liquid ejector head 101 includes a seventh liquid ejector head 101Ka and an eighth liquid ejector head 101Kb corresponding to black (K) ink.

[0044] The printing medium P is conveyed by the conveying device 102 in the direction of arrow A. Printing is performed on the printing medium P by the liquid jet head 101.

[0045] Notice, Figure 1 The liquid jetting device 100 shown is merely an example. The liquid jetting device 100 can be configured such that any type of liquid jetting head 101 can be mounted on the liquid jetting device 100. For example, the liquid jetting head 101 can be configured to jet only one type of ink, or it can be configured to jet more than the four types of ink mentioned above.

[0046] <Liquid Injector Head 101>

[0047] Figure 2 To show Figure 1 A perspective view of any color of the liquid jet head 101 shown. Note that in Figure 2 In the image, the liquid injection head 101 is shown as being in the position of... Figure 1 The orientation is obtained by flipping the liquid injection head 101 up and down as shown.

[0048] like Figure 2 As shown, the liquid jetting head 101 includes a head body 4. Inside the head body 4, a circuit board (not shown) is provided for supplying the power and signals required for jetting liquid. The head body 4 is provided with a plurality of liquid jetting substrates 21, each capable of jetting liquid. Note that in this embodiment, four liquid jetting substrates 21 are provided.

[0049] Each of the plurality of liquid jet substrates 21 includes terminals (not shown). These terminals are connected to the aforementioned circuit board via wiring (not shown). This allows power to be supplied from the circuit board to the energy generating element 1 (see [link to circuit board]). Figure 3B It supplies the electricity and signal required for the jetting liquid, and the energy generating element is configured to generate energy for jetting liquid.

[0050] In each liquid jetting substrate 21, a plurality of jetting ports 5 are formed. Liquid to be jetted from the liquid jetting head 101 is supplied from a liquid tank (not shown) for storing liquid to the liquid jetting substrate 21 via a common supply port (not shown) of the head body 4. On the surface of the jetting ports of the liquid jetting substrate 21 (… Figure 2 In the surface facing upwards, multiple injection ports 5 are arranged along the X direction to form an injection port array.

[0051] Furthermore, a plurality of jet port arrays are formed on the surface of the jet port along the Y direction, which intersects (orthogonal in this embodiment) the X direction. Then, the jet port 5 formed in the end in the X direction is positioned along the Y direction on the jet port 5 of another liquid jet substrate 21. This arrangement of each liquid jet substrate 21 makes printing possible using a long array of jet ports.

[0052] Figure 3A This is a schematic three-dimensional cross-sectional view of the liquid jetting substrate 21.

[0053] like Figure 3A As shown, the liquid jetting substrate 21 includes: a flow channel forming substrate 10 in which a flow channel 2 is formed; and a jetting port forming substrate 50 in which a jetting port 5 is formed.

[0054] A flow channel forming substrate 10 is constructed by forming a device layer 11 on the upper surface of a silicon substrate 12 containing silicon. The device layer includes a silicon layer formed of silicon, a metal film, and an insulating film. In the injection port forming substrate 50, in addition to the injection port 5, a pressure chamber 20 is formed that is subjected to pressure when the liquid is injected.

[0055] Figure 3B This is a schematic cross-sectional view of the liquid jetting substrate 21 viewed along the X direction.

[0056] like Figure 3B As shown, a first functional layer 31 that has the function of protecting the flow channel forming substrate 10 and a second functional layer 41 that has the function of protecting the first functional layer 31 are formed between the injection port forming substrate 50 and the flow channel forming substrate 10.

[0057] With the lower surface of the jet port forming substrate 50 fixed to the upper surface of the device layer 11, the flow channel 2 is formed to penetrate the main body of the flow channel forming substrate 10 along the Z direction. With the lower surface of the jet port forming substrate 50 fixed to the upper surface of the second functional layer 41, the flow channel 2 is connected to the pressure chamber 20. In the jet port forming substrate 50, the pressure chamber 20 is connected to the jet port 5.

[0058] An energy generating element 1 is provided in the device layer 11. The energy generating element 1 is located at a position corresponding to the injection port 5. Note that in this embodiment, a heater is used as the energy generating element 1.

[0059] With the pressure chamber 20 filled with liquid, the heating by the heater causes film boiling in the liquid inside the pressure chamber 20. Using the energy generated by the bubbles produced by this film boiling, the liquid is ejected from the injection port 5. Thus, in the liquid injection substrate 21 of this embodiment, when liquid is to be ejected, liquid is sequentially supplied through the flow channel 2, the pressure chamber 20, and the injection port 5.

[0060] The first functional layer 31 is configured to be resistant to liquids (e.g., ink) and to have coverage capability for covering the flow channel forming substrate 10. For example, preferably, the first functional layer 31 is formed as a metal oxide film containing at least one of Ti, Zr, Hf, V, Nb, and Ta. This configuration allows the first functional layer 31 to achieve both liquid contact properties and coverage capability.

[0061] Then, the first functional layer 31 is formed to continuously cover the lower surface of the flow channel forming substrate 10, the inner peripheral surface of the flow channel 2, and the upper surface of the flow channel forming substrate 10. This structure prevents the components of the flow channel forming substrate 10 from melting into the liquid and prevents the liquid from eroding the flow channel forming substrate 10. In addition, it can sufficiently ensure the adhesion area with the flow channel forming substrate 10.

[0062] However, the first functional layer 31 does not cover the entire upper surface of the flow channel forming substrate 10. The first functional layer 31 is not formed at the location corresponding to the energy generating element 1 on the upper surface of the flow channel forming substrate 10. This is because if the first functional layer 31 were present at these locations, it would hinder the transfer of energy generated by the energy generating element 1 to the liquid.

[0063] In this embodiment, with the injection port forming substrate 50 fixed to the flow channel forming substrate 10, the end portion 31a of the first functional layer 31 is formed on the outside of the injection port forming substrate 50. Forming the end portion 31a of the first functional layer 31 at a position relatively far from the injection port 5 makes it less likely for liquid to penetrate into the interface between the device layer 11 and the first functional layer 31, thereby improving the adhesion between the first functional layer 31 and the device layer 11.

[0064] As described above, the first functional layer 31 is formed to sufficiently ensure adhesion between the first functional layer 31 and the flow channel forming substrate 10. However, there are also cases where the first functional layer 31 may peel off from the flow channel forming substrate 10 for some reason. To suppress such a case, in this embodiment, a second functional layer 41 is formed to protect the first functional layer 31.

[0065] In this embodiment, the second functional layer 41 is formed to cover both the first functional layer 31 covering the upper surface of the flow channel forming substrate 10 and the inner peripheral surface of the flow channel 2. However, on the inner side of the flow channel 2, the second functional layer 41 is formed to cover the first functional layer 31 formed near the outlet of the flow channel 2, but not to cover the first functional layer 31 formed near the inlet of the flow channel 2. Thus, although the first functional layer 31 is formed on the entire inner side of the flow channel 2, the second functional layer 41 is not formed on the entire inner side of the flow channel 2. That is, although the first functional layer 31 is formed on the entire inner side of the flow channel 2, the second functional layer 41 is formed on a portion of the inner side of the flow channel 2.

[0066] Then, the position of the end 41a of the second functional layer 41 in the Y direction is aligned with the position of the end 31a of the first functional layer 31 in the Y direction. According to this configuration, on the upper surface of the flow channel forming substrate 10, the ends 41a of the second functional layer 41 and the first functional layer 31 are formed at positions away from the injection port 5, where liquid is unlikely to adhere. Therefore, since liquid penetration into the interface between the second functional layer 41 and the first functional layer 31 is suppressed, adhesion between the second functional layer 41 and the first functional layer 31 is ensured. Thus, the formation patterns of the first functional layer 31 and the second functional layer 41 are different from each other.

[0067] In addition, the second functional layer 41 has liquid resistance and adhesion to the first functional layer 31.

[0068] In this embodiment, the second functional layer 41 is a film formed of a Si compound selected from the group consisting of SiC, SiOC, SiCN, SiOCN, SiO, SiN, and SiON. However, the material used to form the second functional layer 41 is not limited to the above-mentioned materials, as long as the material has liquid resistance and adhesion to the first functional layer 31.

[0069] To enhance the adhesion between the second functional layer 41 and the first functional layer 31, it is effective to make the stress on the film compressive stress and to increase the stress.

[0070] Here, membrane stress refers to the internal stress of the membrane. Typically, the internal stress of the membrane is assessed by measuring the structural warpage before and after the membrane is formed on the structure, and is expressed as force per unit area. When measuring the stress of a membrane formed on a structure, the stress can be detected by removing the portion of the structure in which the membrane is formed and measuring the structural deformation before and after the membrane removal. Alternatively, in the case of a crystalline structure, the membrane stress can also be detected by assessing the deformation of the crystal lattice caused by stress using methods such as X-ray diffraction.

[0071] In this embodiment, if the stress of the first functional layer 31 is tensile stress, and the stress of the second functional layer 41 is compressive stress, the adhesion between the second functional layer 41 and the first functional layer 31 can be improved.

[0072] On the other hand, if the stress of the first functional layer 31 is compressive stress, and the stress of the second functional layer 41 is compressive stress and its stress value is greater than that of the first functional layer 31, the adhesion between the second functional layer 41 and the first functional layer 31 can be improved.

[0073] However, if the stress value of the second functional layer 41 is too high, and if the flow channel forming substrate 10 is bent significantly for some reason, the adhesion between the second functional layer 41 and the first functional layer 31 may be problematic in some cases.

[0074] Therefore, in this embodiment, the second functional layer 41 is configured such that the stress value falls within a predetermined range. For example, preferably, the stress value of the second functional layer 41 is 100 MPa or more and 600 MPa or less. More preferably, the stress value of the second functional layer 41 is 200 MPa or more and 400 MPa or less. With this configuration, even if the flow channel forming substrate 10 is bent significantly, the adhesion between the second functional layer 41 and the first functional layer 31 can be ensured.

[0075] Furthermore, it is preferable that the Young's modulus of the material of the second functional layer 41 is greater than that of the material of the first functional layer 31. For example, it is preferable that the Young's modulus of the main body of the material used for the second functional layer 41 is 300 GPa or more. More preferably, the Young's modulus of the main body of the material used for the second functional layer 41 is 400 GPa or more. By increasing the Young's modulus of the material of the second functional layer 41 in this way, deformation of the second functional layer 41 is suppressed, thereby ensuring adhesion between the second functional layer 41 and the first functional layer 31.

[0076] Furthermore, it is preferable that the thickness (length in the Z direction) of the second functional layer 41 is greater than the thickness of the first functional layer 31. This is because it is believed that the greater the force required to bend the second functional layer 41, the more difficult it is to physically peel the first functional layer 31 from the flow channel forming substrate 10.

[0077] If the second functional layer 41 is cut into a thin plate shape and deformed with a predetermined curvature, the stress value of the second functional layer 41 is proportional to the thickness of the second functional layer 41. That is, the greater the thickness of the second functional layer 41, the greater the force required to deform the second functional layer 41.

[0078] For example, preferably, the thickness of the second functional layer 41 is 1.5 times or more the thickness of the first functional layer 31. More preferably, the thickness of the second functional layer 41 is 2 times or more the thickness of the first functional layer 31. By making the thickness of the second functional layer 41 greater than the thickness of the first functional layer 31, the rigidity of the second functional layer 41 can be improved, thereby also improving the adhesion of the first functional layer 31 to the flow channel forming substrate 10.

[0079] Furthermore, although described in detail later, it is preferred that the flow channel forming substrate 10 and the first functional layer 31 contain the same material. With this configuration, the interface between the flow channel forming substrate 10 and the first functional layer 31 can be more firmly adhered.

[0080] Therefore, it is preferable that the first functional layer 31 and the second functional layer 41 contain the same material. With this configuration, the interface between the first functional layer 31 and the second functional layer 41 can be more firmly fixed.

[0081] Furthermore, it is preferable that the second functional layer 41 and the jet port forming substrate 50 contain the same material. With this configuration, the interface between the second functional layer 41 and the jet port forming substrate 50 can be more firmly fixed.

[0082] In this way, the quality of the second functional layer 41 and the freedom to select materials can be improved, and the adhesion between the jet port forming substrate 50 and the second functional layer 41 can also be improved.

[0083] In cases where the liquid jetting substrate 21 shrinks, the energy generating element 1 is densified, a new type of ink is used, and the ink is circulated, the structure of fixing the jetting port forming substrate 50 to the second functional layer 41 is particularly preferred.

[0084] Figure 3C This is a schematic cross-sectional view of the liquid jetting substrate 21 viewed along the Y direction.

[0085] like Figure 3C As shown, when viewing the liquid jet substrate 21 along the Y direction, the second functional layer 41 covers the first functional layer 31. By constructing the second functional layer 41 to cover only a portion of the first functional layer 31 in this way, the first functional layer 31 can be protected. That is, the second functional layer 41 can cover only the front surface (the surface viewed along the X direction) of the first functional layer 31, or it can cover only the side surface (the surface viewed along the Y direction) of the first functional layer 31.

[0086] Note that, although in Figure 3C In the example shown, a cross-section of the side surface of the flow channel forming substrate 10 is illustrated, but the first functional layer 31 and the second functional layer 41 can be formed to cover the side surface of the flow channel forming substrate 10. Similarly, with this configuration, the flow channel forming substrate 10 is adequately protected by the first functional layer 31, and the first functional layer 31 is adequately protected by the second functional layer 41.

[0087] Figure 3D This is a schematic plan view of the liquid jetting substrate 21 applicable to this embodiment. Note that, in Figure 3D In the image, the injection port forming substrate 50 is indicated by a dashed line.

[0088] like Figure 3D As shown in the diagram, with the liquid jet substrate 21 viewed in a plan view, the first functional layer 31 (see...) Figure 3B (etc.) are covered by the second functional layer 41.

[0089] Figure 4 A diagram illustrating a comparative example of the liquid jetting substrate 21. To explain the second functional layer 41 (see...). Figure 3B The effects of (etc.) Figure 4 A liquid jetting substrate 21 excluding the second functional layer 41 is shown.

[0090] like Figure 4 As shown in the comparative example, since the second functional layer 41 is not formed, the first functional layer 31 is not protected.

[0091] Examples of methods for forming the first functional layer 31 include the well-known atomic layer deposition (ALD) method. The ALD method is excellent in terms of coverage, but tends to be less effective in terms of adhesion. This is because in the ALD method, the film is formed through physical adsorption.

[0092] Therefore, in the present disclosure, a second functional layer 41 is formed on the first functional layer 31 (see [link]). Figure 3B (etc.) to protect the first functional layer 31. Note that there is no particular limitation on the location where the first functional layer 31 is formed; however, in this embodiment, the second functional layer 41 is formed on the corner 31b of the first functional layer 31. This is because, according to the structure of the liquid jet substrate 21, there is also a possibility that the corner 31b of the first functional layer 31 can easily peel off from the flow channel forming substrate 10.

[0093] Figures 5A to 5F A diagram illustrating an example of a method for manufacturing a liquid jet substrate 21 suitable for this embodiment.

[0094] like Figure 5A As shown, a flow channel forming substrate 10 is fabricated, wherein the lower surface of the device layer 11 is fixed to the upper surface of the silicon substrate 12. However, in this stage, the energy generating element 1 is disposed and the flow channel 2 is formed, but the first functional layer 31 and the second functional layer 41 are not formed.

[0095] like Figure 5B As shown, in Figure 5A A first functional layer 31 is formed on the flow channel forming substrate 10. In this stage, the first functional layer 31 is continuously formed on the upper surface of the device layer 11, the inner peripheral surface of the flow channel 2, and the lower surface of the silicon substrate 12. Note that the first functional layer 31 is formed without sealing the flow channel 2.

[0096] In this embodiment, the first functional layer 31 is formed using the ALD method. Compared to other methods, the ALD method can maintain protection of the flow channel 2. Note that the method used to form the first functional layer 31 is not limited to the ALD method, as long as protection of the flow channel 2 can be maintained.

[0097] like Figure 5C As shown, in Figure 5B A second functional layer 41 is formed on the obtained flow channel forming substrate 10. In this stage, the second functional layer 41 is formed as a whole of the first functional layer 31 covering the upper surface of the covering device layer 11 and a part of the first functional layer 31 covering the inner peripheral surface of the covering flow channel 2.

[0098] In this embodiment, the second functional layer 41 is formed by plasma chemical vapor deposition (plasma CVD). Another example of a method capable of forming the second functional layer 41 includes sputtering. By using plasma CVD or sputtering to form the second functional layer 41, the adhesion of the second functional layer 41 to the substrate 50 formed by the sputtering port can be improved compared to other methods.

[0099] In particular, when forming mask patterns at high density, plasma CVD or sputtering methods are preferred. This is because, compared to other methods, plasma CVD or sputtering methods make it easier to ensure that the second functional layer 41 adheres to the area of ​​the substrate 50 formed by the sputtering port. Note that the method for forming the second functional layer 41 is not limited to plasma CVD or sputtering methods, as long as adhesion to the first functional layer 31 can be ensured.

[0100] like Figure 5D As shown, by using a known method, in Figure 5C A photoresist 6 is formed on the obtained flow channel forming substrate 10, and the photoresist 6 is exposed and developed to form a predetermined photoresist mask. Examples of methods for forming the photoresist 6 include a method that involves laminating the photoresist 6, to be formed as a dry film, onto the flow channel forming substrate 10. Note that the methods for forming the photoresist 6 are not limited to this.

[0101] In this stage of the embodiment, a resist mask is formed to remove the second functional layer 41 and the first functional layer 31 that have been formed at the positions corresponding to the energy generating element 1.

[0102] Furthermore, it is preferable to form a single resist mask shared by the second functional layer 41 and the first functional layer 31. According to this method, the number of steps for forming the resist mask can be reduced compared to forming separate resist masks for the second functional layer 41 and the first functional layer 31.

[0103] like Figure 5E As shown, in Figure 5D The obtained flow channel forming substrate 10 is etched to remove the second functional layer 41 formed at the position corresponding to the energy generating element 1.

[0104] In the etching of this embodiment, the first functional layer 31 is used as a stop layer. By using the first functional layer 31 as a stop layer, the degree of process freedom can be increased while reducing damage to the device layer 11. Examples of methods for removing the second functional layer 41 include dry etching. Note that the method for removing the second functional layer 41 is not limited to dry etching, as long as the method is suitable for the material of the second functional layer 41.

[0105] like Figure 5F As shown, in Figure 5E The obtained flow channel forming substrate 10 is etched to remove the first functional layer 31 formed at the location corresponding to the energy generating element 1. Examples of methods for removing the first functional layer 31 include wet etching. Compared to other methods, wet etching reduces damage to the device layer 11 and facilitates operation control. Note that the method for removing the first functional layer 31 is not limited to wet etching, provided the method is suitable for the material of the first functional layer 31.

[0106] like Figure 5G As shown, by using a known method, from Figure 5F The obtained flow channel forms substrate 10, which is then stripped of resist 6.

[0107] like Figure 5H As shown, by using a known method, in Figure 5G The obtained flow channel forming substrate 10 forms an injection port forming substrate 50.

[0108] The manufacturing method applicable to this embodiment is as described above.

[0109] <Example>

[0110] The following section will describe the methods used in manufacturing. Figure 5H An example of the method of liquid jetting substrate 21 shown.

[0111] First, a silicon substrate 12 is prepared, and a device layer 11 including an energy generating element 1 is formed on the upper surface of the silicon substrate 12.

[0112] Next, flow channels 2 are formed in the flow channel forming substrate 10 formed by the silicon substrate 12 and the device layer 11.

[0113] Next, a TiO film is formed as the first functional layer 31 using the ALD method. The thickness of the TiO film is 50 nm. The tensile stress of the TiO film is 300 MPa.

[0114] Next, a SiC film is formed as the second functional layer 41 using a plasma CVD method. The thickness of this SiC film is 100 nm. The compressive stress of this SiC film is 300 MPa. According to literature values, the Young's modulus of TiO2 used as the material is 290 GPa, and the Young's modulus of SiC used as the material is 440 GPa. Thus, the Young's modulus of the second functional layer 41 is greater than that of the first functional layer 31.

[0115] Next, a photoresist 6 is formed on the flow channel forming substrate 10. Within the photoresist 6, a photoresist mask is formed that serves both for etching the SiC film and etching the TiO film.

[0116] Next, the SiC film is patterned. During the etching process of this patterning, dry etching is performed. In this dry etching, the TiO film is used as a stop layer.

[0117] Next, the TiO film is patterned. Wet etching is then performed during the patterning process.

[0118] Next, remove resist 6.

[0119] Next, the jet port forming substrate 50 is formed.

[0120] This example is as described above.

[0121] <Comparative Example>

[0122] The following section will describe the methods used in manufacturing. Figure 4 A comparative example of the method of liquid jetting substrate 21 shown.

[0123] First, a silicon substrate 12 is prepared, and a device layer 11 including an energy generating element 1 is formed on the upper surface of the silicon substrate 12.

[0124] Next, flow channels 2 are formed in the flow channel forming substrate 10 formed by the silicon substrate 12 and the device layer 11.

[0125] Next, a TiO film is formed as the first functional layer 31 in the same manner as in the example.

[0126] Next, a photoresist 6 is formed on the flow channel forming substrate 10. A photoresist mask with the same pattern as in the example is formed in the photoresist 6.

[0127] Next, the TiO film is patterned. Wet etching is then performed during the patterning process.

[0128] Next, remove resist 6.

[0129] Next, the jet port forming substrate 50 is formed.

[0130] The liquid jetting substrates obtained by the example manufacturing method and the liquid jetting substrates obtained by the comparative example manufacturing method were immersed in ink and evaluated. The evaluation results showed that the ends of the first functional layer 31 of the liquid jetting substrate in the comparative example were more likely to detach than the ends of the first functional layer 31 of the liquid jetting substrate in the example. Therefore, it is shown that the adhesion of the first functional layer 31 to the flow channel forming substrate 10 in the example is improved compared to the adhesion of the first functional layer 31 to the flow channel forming substrate 10 in the comparative example.

[0131] As described above, in this embodiment, due to the formation of the second functional layer 41, the thickness of the functional layer protecting the flow channel forming substrate 10 is increased compared to the case where the second functional layer 41 is not formed. In other words, in this embodiment, the rigidity of the functional layer protecting the flow channel forming substrate 10 is increased compared to the case where the second functional layer 41 is not formed. Therefore, compared to the case where the second functional layer 41 is not formed, the possibility of the first functional layer 31 peeling off can be reduced.

[0132] Therefore, the liquid jet substrate according to this embodiment can improve the adhesion between the flow channel forming substrate and the functional layer.

[0133] [First Modification of the First Embodiment]

[0134] Figure 6A This is a schematic cross-sectional view of the liquid jetting substrate 21 in the first modified example.

[0135] Figure 6B This is a schematic plan view of the liquid jetting substrate 21 in the first modified example. Figure 6B In the diagram, for ease of description, the injection port forming substrate 50 is indicated by dashed lines. Similarly, in the plan view given below, it is shown in conjunction with... Figure 6B The same method is used to form the substrate 50 by marking the injection port with dashed lines.

[0136] like Figure 6A and Figure 6B As shown, the first functional layer 31 and the second functional layer 41 may be formed only on the upper surface of the device layer 11 inside the substrate 50 forming the injection port. In this modified example, the second functional layer 41 covers only the area near the outlet of the flow channel 2 on the upper surface of the first functional layer 31.

[0137] For example, in the state of observing the cross-section of the liquid jet substrate 21 along the X direction (see...) Figure 6AThe adhesive portion between the first functional layer 31 and the second functional layer 41 has a length of 0.1 μm or more in the Y direction. Preferably, the adhesive portion between the first functional layer 31 and the second functional layer 41 has a length of 1.0 μm or more in the Y direction. More preferably, the adhesive portion between the first functional layer 31 and the second functional layer 41 has a length of 5.0 μm or more in the Y direction. This is because the longer the adhesive portion between the first functional layer 31 and the second functional layer 41 is in the Y direction, the better the adhesion between the first functional layer 31 and the second functional layer 41 can be.

[0138] Similarly, this structure can improve the adhesion between the flow channel forming substrate and the functional layer.

[0139] [Second Modification of the First Embodiment]

[0140] Figure 6C This is a schematic cross-sectional view of the liquid jetting substrate 21 in the second modified example.

[0141] Figure 6D This is a schematic plan view of the liquid jetting substrate 21 in the second modified example.

[0142] like Figure 6C and Figure 6D As shown, the second functional layer 41 may have a configuration that covers the corner of the first functional layer 31 from the inner peripheral surface to the upper surface of the flow channel 2 near the outlet of the flow channel 2.

[0143] With this configuration, since the interface between the first functional layer 31 and the device layer 11 is covered by the second functional layer 41, liquid penetration into the interface between the first functional layer 31 and the device layer 11 can be suppressed. Note that in this configuration, the surface of the liquid jetting substrate 21 facing the X direction can be covered by the second functional layer 41. Similarly, in the following modified example, the surface of the liquid jetting substrate 2 facing the X direction can be covered by the second functional layer 41.

[0144] Similarly, this structure can improve the adhesion between the flow channel forming substrate and the functional layer.

[0145] [Third Modification of the First Embodiment]

[0146] Figure 6E This is a schematic cross-sectional view of the liquid jetting substrate 21 in the third modified example.

[0147] Figure 6F This is a schematic plan view of the liquid jetting substrate 21 in the third modified example.

[0148] like Figure 6E and Figure 6FAs shown, in this modified example, the second functional layer 41 covers the entire first functional layer 31 inside the flow channel 2. Then, the second functional layer 41 covers the upper surface of the flow channel forming substrate 10 in a wider area than the first functional layer 31.

[0149] For example, if the first functional layer 31 is formed of resin, adhesion between the jet port forming substrate 50 and the first functional layer 31 may occur. Specifically, if the first functional layer 31 is formed of epoxy resin, silicone, benzocyclobutene, polyimide, etc., adhesion between the jet port forming substrate 50 and the first functional layer 31 may occur.

[0150] Furthermore, if there is a layer at the interface between the flow channel forming substrate 10 and the first functional layer 31 that is likely to dissolve into the ink and the novel ink has already penetrated into that layer, the adhesion between the first functional layer 31 and the flow channel forming substrate 10 may be problematic.

[0151] For example, if the ink contains a novel surfactant, the ink may penetrate into the interface between the flow channel forming substrate 10 and the first functional layer 31. Furthermore, when using ink intended for directly etching patterns onto metal or the like, the ink may also penetrate into the interface between the flow channel forming substrate 10 and the first functional layer 31. In addition, when using acidic or alkaline inks or inks intended for direct circuit printing, adhesion between the first functional layer 31 and the flow channel forming substrate 10 may be problematic.

[0152] Furthermore, when using ink that is likely to penetrate into the interface between the jet port forming substrate 50 and the first functional layer 31, or ink that is likely to expand, adhesion between the first functional layer 31 and the jet port forming substrate 50 may become problematic. For example, if the ink contains novel surfactants or organic solvents, the ink may penetrate into the interface between the jet port forming substrate 50 and the first functional layer 31. Additionally, when the ink is heated or circulated, the ink may penetrate into the interface between the jet port forming substrate 50 and the first functional layer 31, causing either the jet port forming substrate 50 or the first functional layer 31 to dissolve.

[0153] However, according to the construction of this modified example, the interface between the jet port forming substrate 50 and the first functional layer 31 is covered by the second functional layer 41. This makes it possible to suppress liquid penetration into the interface between the jet port forming substrate 50 and the first functional layer 31.

[0154] Therefore, compared with the structure in which the interface between the jet port forming substrate 50 and the first functional layer 31 is not covered, the structure of this modified example can improve the adhesion between the first functional layer 31 and the flow channel forming substrate 10.

[0155] Furthermore, in this modified example, the first functional layer 31, which is continuously formed on the lower surface of the silicon substrate 12, the inner peripheral surface of the flow channel 2, and the upper surface of the device layer 11, is also continuously covered by the second functional layer 41. By forming the second functional layer 41 such that the second functional layer 41 extending from one of the plurality of flow channels 2 enters another flow channel 2, adhesion can be further improved.

[0156] In this way, a second functional layer 41 continuously protects the corresponding openings of multiple flow channels 2, and thus can further ensure the adhesion area.

[0157] In addition, in the same configuration, since the end 41a of the second functional layer 41 is formed between the device layer 11 and the jet port forming substrate 50, the end 41a of the second functional layer 41 located on the upper surface of the device layer 11 is protected by the jet port forming substrate 50.

[0158] This structure can improve the adhesion between the flow channel forming substrate and the functional layer.

[0159] [Fourth Modification of the First Embodiment]

[0160] Figure 6G This is a schematic cross-sectional view of the liquid jetting substrate 21 in the fourth modified example.

[0161] Figure 6H This is a schematic plan view of the liquid jetting substrate 21 in the fourth modified example.

[0162] like Figure 6G and Figure 6H As shown, the first functional layer 31 and the second functional layer 41 can be formed from the inside of the jet port forming substrate 50 to the middle between the device layer 11 and the jet port forming substrate 50.

[0163] With this configuration, since the ends of the first functional layer 31 and the second functional layer 41 are protected by the injection port forming substrate 50, liquid penetration into the interface between the device layer 11 and the first functional layer 31 can be suppressed.

[0164] In addition, such as Figure 6H As shown, a second functional layer 41 can continuously protect the outlets of multiple flow channels 2 formed along the Y direction.

[0165] Similarly, this structure can improve the adhesion between the flow channel forming substrate and the functional layer.

[0166] [Fifth Modification of the First Embodiment]

[0167] Figure 6I This is a schematic cross-sectional view of the liquid jetting substrate 21 in the fifth modified example.

[0168] Figure 6J This is a schematic plan view of the liquid jetting substrate 21 in the fifth modified example.

[0169] like Figure 6I and Figure 6J As shown, the first functional layer 31 and the second functional layer 41 can be formed from the inside of the jet port forming substrate 50 to the middle between the device layer 11 and the jet port forming substrate 50.

[0170] With this configuration, since the ends of the first functional layer 31 and the second functional layer 41 are protected by the injection port forming substrate 50, liquid penetration into the interface between the device layer 11 and the first functional layer 31 can be suppressed.

[0171] In addition, such as Figure 6J As shown, a second functional layer 41 can continuously protect the outlets of multiple flow channels 2 formed along the X direction.

[0172] When the energy generating elements 1 are arranged at a high density and the interval between the two injection ports 5 in the X direction is short, the construction of the second functional layer 41 continuously protecting multiple flow channels 2, as in this modified example, is particularly effective.

[0173] For example, when the interval between the two injection ports 5 is 40 μm or less, the configuration of this modified example is preferred. When the interval between the two injection ports 5 is 20 μm or less, the configuration of this modified example is more preferred. When the interval between the two injection ports 5 is 10 μm or less, the configuration of this modified example is even more preferred.

[0174] Similarly, this structure can improve the adhesion between the flow channel forming substrate and the functional layer.

[0175] [Sixth Modification of the First Embodiment]

[0176] Figure 6K This is a schematic cross-sectional view of the liquid jetting substrate 21 in the sixth modified example.

[0177] Figure 6L This is a schematic plan view of the liquid jetting substrate 21 in the sixth modified example.

[0178] like Figure 6K and Figure 6L As shown, in this modified example, the second functional layer 41 covers the corner of the first functional layer 31 from the inner peripheral surface of the flow channel 2 to its upper surface, and covers the interface between the device layer 11 and the first functional layer 31 near the outlet of the flow channel 2.

[0179] Similarly, with this structure, since the interface between the device layer 11 and the first functional layer 31 is protected by the second functional layer 41, liquid penetration into the interface between the device layer 11 and the first functional layer 31 can be suppressed.

[0180] [Second Embodiment]

[0181] In the first embodiment, a heater is used as the energy generating element 1. However, in this embodiment, a piezoelectric element is used as the energy generating element 1. Note that in this embodiment, the device layer 11 includes a vibrating plate (not shown) that deforms according to the drive of the piezoelectric element. Liquid is sprayed by driving the vibrating plate. In the following description, constructions that are the same as or corresponding to those in the first embodiment are indicated by the same symbols, and the differences will be mainly described.

[0182] Figure 7A This is a schematic cross-sectional view of the liquid jetting substrate 21 in this embodiment.

[0183] like Figure 7A As shown, the second functional layer 41 includes a structure that covers the corner of the first functional layer 31 from the inner circumferential surface of the flow channel 2 to its upper surface near the outlet of the flow channel 2.

[0184] Similarly, this structure can improve the adhesion between the flow channel forming substrate and the functional layer.

[0185] [First Modification of the Second Embodiment]

[0186] Figure 7B This is a schematic cross-sectional view of the liquid jetting substrate 21 in this modified example.

[0187] like Figure 7B As shown, the end 31a of the first functional layer 31 and the end 41a of the second functional layer 41 are located between the device layer 11 and the injection port forming substrate 50.

[0188] By positioning the ends 31a of the first functional layer 31 and the second functional layer 41 inside the injection port forming substrate 50 and outside the pressure chamber 20, liquid penetration into the interface between the device layer 11 and the first functional layer 31 can be suppressed.

[0189] [Second Modification of the Second Embodiment]

[0190] Figure 7C This is a schematic cross-sectional view of the liquid jetting substrate 21 in this modified example.

[0191] like Figure 7CAs shown, in this modified example, the jet port forming substrate 50 includes a first layer 50a and a second layer 50b. By forming the jet port forming substrate 50 via laminating multiple layers, the required functions of the jet port forming substrate 50 can be distributed to the respective layers.

[0192] By forming the jet port forming substrate 50 by laminating multiple layers in this manner, the design freedom of the jet port forming substrate 50 can be improved. Note that this also applies to... Figure 7D The modified example.

[0193] The lower surface of the second layer 50b is fixed to the upper surface of the device layer 11. By using the same material to form both the second layer 50b and the device layer 11, the steps for forming these layers can be simplified.

[0194] For example, if the upper surface of device layer 11 is formed of silicon, the lower surface of the second layer 50b can also be formed of silicon. Alternatively, if the upper surface of device layer 11 is formed of stainless steel, the lower surface of the second layer 50b can also be formed of stainless steel. Note that the materials used to form the upper surface of device layer 11 and the lower surface of the second layer 50b are not limited to silicon or stainless steel.

[0195] The lower surface of the first layer 50a is fixed to the upper surface of the second layer 50b. The injection port 5 is formed in the first layer 50a.

[0196] Furthermore, the end 31a of the first functional layer 31 and the end 41b of the second functional layer 41 are located between the first layer 50a and the second layer 50b. Similarly, this configuration can suppress liquid permeation into the interface between the device layer 11 and the first functional layer 31.

[0197] [Third Modification of the Second Embodiment]

[0198] Figure 7D This is a schematic cross-sectional view of the liquid jetting substrate 21 in this modified example.

[0199] like Figure 7D As shown, in this modified example, the first functional layer 31 continuously covers the lower surface of the silicon substrate 12, the inner peripheral surface of the flow channel 2, the pressure chamber 20, the jet port 5, and the upper surface (jet port surface) of the jet port forming substrate 50.

[0200] The second functional layer 41 covers the first functional layer 31 formed on the surface of the injection port from the inside of the injection port 5.

[0201] Incidentally, the manufacturing process for the liquid jetting substrate 21 includes a cutting step (not shown). According to the configuration of this modified example, after cutting, the ends of the first functional layer 31 and the second functional layer 41 are located at the ends of the liquid jetting substrate 21 that have been cut in this way.

[0202] Therefore, by adopting the same structure, liquid penetration into the interface between the device layer 11 and the first functional layer 31 can be suppressed.

[0203] [Other embodiments]

[0204] Although in the above embodiment, the stop layer is only used in the etching of the second functional layer 41, it can also be used in the etching of the first functional layer 31. For example, a film can be formed on the device layer that is suitable as a stop layer for etching the first functional layer 31 and the second functional layer 41. Specifically, it is preferred that these films are formed of Ir (iridium), Pt (platinum), etc. According to this configuration, damage to the device layer during etching can be reduced, and etching control is facilitated.

[0205] In the above embodiments, the liquid jetting device 100 used includes a linear head (page-width head) that is longer in the page width direction (X direction) of the printing medium. However, the technology of this disclosure can also be applied to liquid jetting devices that include a liquid jetting head that scans in a plane along a scanning direction (X direction) intersecting the transport direction (Y direction) of the printing medium P. That is, the technology of this disclosure can also be applied to so-called serial liquid jetting devices.

[0206] According to the liquid jetting substrate disclosed herein, the adhesion between the flow channel forming substrate and the functional layer can be further improved.

[0207] Although this disclosure has been described with reference to embodiments, it should be understood that this disclosure is not limited to the disclosed embodiments. The scope of the following claims is accorded the broadest interpretation to cover all such modifications and equivalent structures and functions.

Claims

1. A liquid jetting substrate configured to jet liquid, the liquid jetting substrate comprising: A flow channel forming substrate has a first surface, a second surface, and a flow channel, wherein the second surface faces a direction opposite to that of the first surface, and the flow channel extends from the first surface to the second surface and is configured to allow liquid to flow through the flow channel. A first functional layer covers the second surface and the inner peripheral surface of the flow channel; and A second functional layer covers the first functional layer formed on the second surface of the flow channel forming substrate.

2. The liquid jetting substrate according to claim 1, wherein, The first functional layer continuously covers the second surface and the inner peripheral surface of the flow channel.

3. The liquid jetting substrate according to claim 2, wherein, Inside the flow channel, the second functional layer covers the entire first functional layer.

4. The liquid jetting substrate according to claim 1 or 2, wherein, The stress in the first functional layer is tensile stress, and The stress in the second functional layer is compressive stress.

5. The liquid jetting substrate according to claim 1 or 2, wherein, The stress in the first functional layer is compressive stress. The stress in the second functional layer is compressive stress, and The stress value of the second functional layer is greater than the stress value of the first functional layer.

6. The liquid jetting substrate according to claim 1 or 2, wherein, The Young's modulus of the material in the second functional layer is greater than that of the material in the first functional layer.

7. The liquid jetting substrate according to claim 1 or 2, wherein, The second functional layer is thicker than the first functional layer.

8. The liquid jetting substrate according to claim 1 or 2, wherein, The first functional layer is a metal oxide film containing at least one of Ti, Zr, Hf, V, Nb, and Ta, and The second functional layer is a Si compound selected from the group consisting of SiC, SiOC, SiCN, SiOCN, SiO, SiN, and SiON.

9. The liquid jetting substrate according to claim 1 or 2, wherein, In the state of viewing the second surface in the plan view, one of the second functional layers continuously covers the outer periphery of the openings of the plurality of flow channels.

10. The liquid jetting substrate according to claim 1 or 2, wherein, In the state of viewing the second surface in the plan view, one of the first functional layers continuously covers the outer periphery of the openings of the plurality of flow channels.

11. The liquid jetting substrate of claim 1, further comprising a jetting port forming substrate, the jetting port forming substrate including a jetting port configured to jet liquid supplied via the flow channel, wherein, At least one end of the second functional layer is located at a position where the end is not in contact with the liquid.

12. The liquid jetting substrate of claim 11, further comprising a jetting port forming substrate, the jetting port forming substrate including a jetting port configured to jet liquid supplied via the flow channel, wherein, At least one end of the first functional layer is located at a position where the end is not in contact with the liquid.

13. The liquid jetting substrate according to claim 11, wherein, One end of the first functional layer and one end of the second functional layer are located between the flow channel forming substrate and the injection port forming substrate.

14. The liquid jetting substrate according to claim 11, wherein, In the injection port forming substrate, a plurality of injection ports are arranged along a first direction, and In the state of viewing the second surface in a plan view, one of the second functional layers covers the outer periphery of the opening of a plurality of flow channels formed along the first direction.

15. The liquid jetting substrate according to claim 11, wherein, In the injection port forming substrate, a plurality of injection ports are arranged along a first direction, and In the state of viewing the second surface in the plan view, one of the second functional layers covers the outer periphery of the opening of a plurality of flow channels formed along a second direction intersecting the first direction.

16. The liquid jetting substrate according to claim 13, wherein, In the flow channel forming substrate, an energy generating element configured to generate energy for ejecting liquid from the injection port is formed at a position facing the injection port. In the flow channel forming substrate, the second functional layer is not formed at the position corresponding to the energy generating element.

17. The liquid jetting substrate according to claim 16, wherein, The energy-generating element is a heater.

18. The liquid jetting substrate according to claim 16, wherein, The energy generating element is a piezoelectric element.

19. A liquid jet head, the liquid jet head comprising a liquid jetting substrate configured to jet a liquid, wherein, The liquid jetting substrate includes: A flow channel forming substrate has a first surface, a second surface, and a flow channel, wherein the second surface faces a direction opposite to that of the first surface, and the flow channel extends from the first surface to the second surface and is configured to allow liquid to flow through the flow channel. A first functional layer, the first functional layer covering the second surface and the inner peripheral surface of the flow channel; and A second functional layer covers the first functional layer formed on the second surface of the flow channel forming substrate.

20. A method for manufacturing a liquid jetting substrate, the liquid jetting substrate being configured to jet liquid, the method comprising: The preparation step involves preparing a flow channel forming substrate having a first surface, a second surface, and a flow channel. The second surface faces a direction opposite to that of the first surface. The flow channel extends from the first surface to the second surface and is configured to allow liquid to flow through the flow channel. The first forming step involves forming a first functional layer on the second surface and the inner peripheral surface of the flow channel. The second forming step involves forming a second functional layer on the first functional layer formed on the second surface of the flow channel forming substrate. The first etching step is to etch the second functional layer. and The second etching step etches the first functional layer.

21. The method for manufacturing a liquid jet substrate according to claim 20, wherein, In the first formation step, the first functional layer is formed using the ALD method, and In the second formation step, the second functional layer is formed by plasma CVD or sputtering.

22. The method for manufacturing a liquid jet substrate according to claim 20 or 21, wherein, A shared mask is used in both the first and second etching steps.

23. The method for manufacturing a liquid jet substrate according to claim 22, wherein, In the first etching step, dry etching is performed, and In the second etching step, wet etching is performed.

24. The method for manufacturing a liquid jet substrate according to claim 20 or 21, wherein, In the first etching step, the first functional layer is used as a stop layer.

25. The method for manufacturing a liquid jet substrate according to claim 20 or 21, wherein, The second surface of the substrate forming the flow channel contains Ir or Pt, and In the first etching step, the second surface serves as a stop layer.

26. The method for manufacturing a liquid jet substrate according to claim 20 or 21, wherein, The second surface of the substrate forming the flow channel contains Ir or Pt, and In the second etching step, the second surface serves as a stop layer.

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