Liquid ejection head, element substrate, and method for manufacturing the same

Abstract

To manufacture a liquid discharge head which is good in accuracy of shape and dimension of an opening constituting a discharge port and has high resistance against various liquids, and an element substrate.SOLUTION: A method for manufacturing an element substrate 1 of a liquid discharge head includes the steps of: forming a silicon-based membrane layer 13 containing carbon on one face 16a of a base board 16; laminating a silicon substrate 12 on the membrane layer 13 formed on the one face 16a of the base board 16, and joining the silicon substrate 12 to the membrane layer 13; processing to make the silicon substrate 12 joined to the membrane layer 13 into the membrane layer 13 as a stop layer, thereby forming a lower hole part 14; processing to make the base board 16 into the membrane layer 13 as the stop layer, and removing the base board 16 to expose the membrane layer 13; and forming an opening 15 communicating with the lower hole part 14 in the exposed membrane layer 13.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a liquid ejection head, an element substrate, and methods for manufacturing them.

Background Art

[0002] In recent liquid ejection heads, various liquid inks, for example, pigment-based inks having a pH of about 8 to 9, are used to form high-quality image quality. However, by using such inks, Si or SiO, which is a general material of the discharge port forming member, may dissolve, and the shape and dimensions of the discharge port may change. In the method for manufacturing a nozzle substrate (discharge port forming member) of a liquid ejection head described in Patent Document 1, after forming a recess serving as a nozzle hole in a silicon substrate coated with a thermal oxide film (SiO2 film), the SiO2 film is removed. Then, after coating again with an oxide-based metal film (for example, SiO2 film or the like) which is an ink-resistant protective film, a glass substrate is laminated. In the method for manufacturing a nozzle substrate of a liquid ejection head described in Patent Document 2, after forming a recess in a silicon substrate coated with a SiO2 film, the SiO2 film is removed and coated with a Ta2O5 film.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the method for manufacturing a discharge port forming member of a liquid discharge head described in Patent Document 1, for example, an oxide-based metal film such as an SiO2 film is formed, but the chemical resistance is not sufficient. Further, since the entire discharge port forming member is completely covered with the oxide-based metal film, the manufacturing process is complicated. The discharge port of the liquid discharge head described in Patent Document 2 has high resistance to alkaline liquids, but since it is necessary to completely cover the entire discharge port forming member with a Ta2O5 film, the manufacturing process is as complicated as the method of Patent Document 1.

[0005] Therefore, an object of the present invention is to manufacture a liquid discharge head and an element substrate in which the shape and dimensional accuracy of the opening constituting the discharge port are good and the resistance to various liquids is high.

Means for Solving the Problems

[0006] The method for manufacturing an element substrate of a liquid discharge head according to the present invention includes a step of forming a silicon-containing carbon film layer on one surface of a base substrate, a step of laminating a silicon substrate on the film layer formed on the one surface of the base substrate, and bonding the silicon substrate to the film layer, a step of performing processing using the film layer as a stop layer on the silicon substrate bonded to the film layer to form a lower hole portion, a step of performing processing using the film layer as a stop layer on the base substrate to remove the base substrate and expose the film layer, and a step of forming an opening communicating with the lower hole portion in the exposed film layer.

Effects of the Invention

[0007] According to the present invention, it is possible to manufacture a liquid discharge head and an element substrate in which the shape and dimensional accuracy of the opening constituting the discharge port are good and the resistance to various liquids is high.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. [Configuration of Liquid Ejection Head] FIG. 1 shows a liquid ejection head including an element substrate 1 manufactured based on the manufacturing method of the present invention. The liquid ejection head includes the element substrate 1, a liquid container (for example, an ink tank) 2 that supplies a liquid (for example, ink) to the element substrate 1, and an electrical wiring member (for example, a flexible wiring board) 3 that supplies an electrical signal to the element substrate 1. For convenience, in FIG. 1, the liquid container 2 and the electrical wiring member 3 are schematically illustrated.

[0010] The element substrate 1 is a laminate of a substrate 4 and a discharge port forming member 5. The substrate 4 has a supply path 6 connected to the liquid container 2 for supplying liquid from the liquid container 2, and a groove portion 7a that constitutes a flow path 7 communicating with the supply path 6. This groove portion 7a is a recess provided on a bonding surface 4a of the substrate 4 to be bonded to the discharge port forming member 5. When the substrate 4 is bonded to the discharge port forming member 5, the opening portion of the groove portion 7a is substantially blocked by the discharge port forming member 5 to form the flow path 7. A discharge port 8 is formed in the discharge port forming member 5, and the flow path 7 communicates with the discharge port 8 of the discharge port forming member 5 (more specifically, the through hole portion 14 of the silicon substrate 12). A part of the wall of the flow path 7 on the side opposite to the silicon substrate side (the side opposite to the bonding surface 4a of the substrate 4) is constituted by a flexible diaphragm 9. And a hollow cavity portion 10 is provided at a position on the side opposite to the flow path 7 (the side opposite to the bonding surface 4a of the substrate 4) with the diaphragm 9 interposed therebetween. An energy generating element for applying discharge energy for discharging the liquid in the flow path from the discharge port 8 to the outside is disposed on the diaphragm 9. In the present embodiment, a piezoelectric element (piezo element) 11, which is an example of an energy generating element, is disposed on the diaphragm 9. An electrical wiring member 3 (for example, a flexible wiring board) is connected to the piezoelectric element 11 via wiring (not shown).

[0011] The discharge port forming member 5 is composed of a silicon substrate 12 and a film layer 13 formed on the surface of the silicon substrate 12. The silicon substrate 12 is provided with a through hole portion 14 penetrating the silicon substrate 12. The film layer 13 is provided with an opening portion 15 having a smaller diameter than the through hole portion 14 and penetrating the film layer 13. The through hole portion 14 and the opening portion 15 are concentrically arranged and communicate with each other to form the discharge port 8. The film layer 13 is a silicon-based film layer containing carbon (for example, SiC film). The end portion exposed outside the discharge port 8, that is, the inner peripheral surface of the opening portion 15, is composed only of the silicon-based film layer 13 containing carbon. The film layer 13 may be composed of at least one film of SiC film, SiOC film, SiCN film, and SiOCN film.

[0012] According to this liquid ejection head, liquid is supplied from the liquid container 2 to the flow path 7 via the supply path 6. Then, when an electrical signal is supplied to the piezoelectric element 11 from the electrical wiring member 3 via wiring (not shown), the piezoelectric element 11 causes the diaphragm 9 to deflect and deform due to the piezoelectric effect, applying pressure (ejection energy) to the liquid in the flow path 7. A part of the liquid in the flow path 7 to which pressure is applied from the piezoelectric element 11 and the diaphragm 9 is ejected to the outside from the ejection port 8 as droplets. The droplets thus ejected to the outside from the ejection port 8 adhere to a recording medium (not shown) located outside the liquid ejection head, for example, and image formation or the like is performed.

[0013] [Method for manufacturing a liquid ejection head] The method for manufacturing the liquid ejection head shown in FIG. 1 will be described. FIGS. 2(A) to 2(H) are cross-sectional views showing the respective steps of the method for manufacturing the liquid ejection head of the present embodiment in order. First, as shown in FIG. 2(A), a film layer 13 is formed on one surface 16a of the lower base substrate 16, and the film layer 13 is surface-treated. Subsequently, as shown in FIG. 2(B), the silicon substrate 12 is laminated on the film layer 13 on the lower base substrate 16 and joined to the film layer 13. Thereby, the film layer 13 is sandwiched between the silicon substrate 12 and the lower base substrate 16. Preferably, the lower base substrate 16 is a silicon substrate made of the same silicon as the silicon substrate 12, and the film layer 13 is made of a silicon carbide-based film layer containing carbon (for example, SiC film). The film layer 13 is sandwiched inside one laminate (silicon member) formed by joining a pair of silicon substrates (the silicon substrate 12 and the lower base substrate 16). As shown in FIG. 2(C), the silicon substrate 12 is ground or polished from the side opposite to the film layer 13 and the lower base substrate 16 so that the total thickness of the silicon substrate 12 and the film layer 13 becomes a desired thickness (the thickness of the desired ejection port forming member 5). As shown in FIG. 2(D), with the total thickness of the silicon substrate 12 and the film layer 13 having reached the desired thickness, the silicon substrate 12 is processed (etched) to form a lower hole portion 14 that becomes a part of the ejection port 8. During this etching process, by utilizing the etching rate difference between the silicon substrate 12 and the film layer 13 made of SiC or the like, the film layer 13 can function as a stop layer (etching stop layer).

[0014] As shown in FIG. 2(E), a substrate 4 on which a piezoelectric element 11, a diaphragm 9, a cavity 10, a supply path 6, and a groove portion 7a are formed is prepared. Then, as shown in FIG. 2(F), the substrate 4 is laminated and bonded to the laminate (silicon member) shown in FIG. 2(D). Thereby, the opening portion of the groove portion 7a is substantially blocked by the discharge port forming member 5 to constitute the flow path 7. As shown in FIG. 2(G), at least a part of the base substrate 16 is processed (ground or polished or etched) from the side opposite to the silicon substrate 12 and the film layer 13 to expose the film layer 13. Also during this processing, the film layer 13 can be made to function as a stop layer by utilizing the grinding or polishing speed difference or the etching rate difference between the base substrate 16 made of silicon and the film layer 13 made of SiC or the like.

[0015] As shown in FIG. 2(H), the film layer 13 is etched to form an opening 15, and the counterbore 14 and the opening 15 are communicated to constitute the discharge port 8. In this way, the element substrate 1 of the liquid discharge head, which is a laminate of the discharge port forming member 5 composed of the silicon substrate 12 and the film layer 13 and the substrate 4, is manufactured. Further, an electrical wiring member (for example, a flexible wiring board) 3 is connected to the piezoelectric element 11 via wiring (not shown), a liquid container (for example, an ink tank) 2 is connected to the supply path 6, and other members (not shown) are further assembled to complete the liquid discharge head (see FIG. 1).

[0016] The film layer 13 of the present embodiment is composed of a silicon-based film layer containing carbon. Depending on the carbon content, the silicon-based film layer has high resistance to various substances, such as ink resistance, acid resistance, alkali resistance, and etching resistance. Therefore, compared with the silicon substrate 12 and the base substrate 16 made of silicon that do not contain carbon, the silicon-based film layer 13 containing carbon has a slower grinding or polishing speed and etching speed, and functions as a stop layer in grinding or polishing and etching. By adjusting the carbon content in the film layer 13, the film layer 13 can function as an appropriate stop layer. As an example, if the carbon content is 1% or more, more preferably 5% or more, as the composition ratio of the amorphous silicon-based film layer 13, it can exhibit sufficient function as an etching stop layer. As a result, an opening 15 (the end portion exposed outside the discharge port 8) with good shape and dimensional accuracy can be formed. Moreover, the film layer 13 has ink resistance, and even during long-term use of the liquid ejection head, it is difficult for the thickness of the discharge port forming member 5 to decrease or the discharge port 8 to deform, and good liquid ejection performance is maintained.

[0017] According to the present embodiment, the film layer 13 formed on the base substrate 16 is transferred to the silicon substrate 12. Thereby, the film layer 13 can be easily and accurately formed. Since the base substrate 16 is finally removed and does not remain in the completed liquid ejection head, it is not necessary to form various concave portions, convex portions, etc. Therefore, the surface (one surface) 16a of the base substrate 16 on which the film layer 13 is formed can be formed flat. As a result, good film formation is possible without performing processing for flattening irregularities or filling members on the surface 16a of the base substrate 16. In particular, when a film layer 13 having a crystal structure is formed on the base substrate 16 by epitaxial growth and transferred to the silicon substrate 12, a film layer 13 with few defects and high mechanical strength can be formed. Also, a film layer 13 made of amorphous SiC or the like can be formed on the base substrate 16 by the PE-CVD method (plasma-enhanced chemical vapor deposition method) and transferred to the silicon substrate 12. In that case, by performing the PE-CVD method while appropriately controlling the film stress and density, a good film layer 13 can be formed at low cost.

[0018] Furthermore, according to the present embodiment, the silicon substrate 12 and the film layer 13 constituting the discharge port forming member 5 can be transported or processed (for example, thinning the silicon substrate 12 or forming a pilot hole) in a state where the base substrate 16 is joined. Even when the thickness of the silicon substrate 12 is thin (for example, about 100 μm), since the base substrate 16 functions as a support member for the silicon substrate 12, the transportation and processing of the silicon substrate 12 can be stably and favorably performed. Further, by transferring the film layer 13 formed on the base substrate 16 to the silicon substrate 12, the front and back surfaces of the film layer 13 are swapped. That is, the surface that was in contact with the base substrate 16 of the film layer 13 is exposed to the outside without contacting the silicon substrate 12, and the surface that was exposed to the outside without contacting the base substrate 16 of the film layer 13 contacts the silicon substrate 12. By utilizing this swapping of the front and back surfaces of the film layer 13, the surface of the discharge port forming member 5 that becomes the liquid discharge surface of the liquid discharge head can be made smooth and good. For example, when the surface of the film layer 13 that contacts the surface (one surface) 16a of the base substrate 16 formed flat as described above is formed smoothly, that smooth surface can be made the liquid discharge surface of the completed liquid discharge head. Thereby, good liquid discharge performance can be obtained.

[0019] [Other Embodiments] In the embodiments shown in FIGS. 1 and 2, the piezoelectric element 11 is used as the energy generating element that generates discharge energy. However, even in a liquid discharge head in which another type of energy generating element (for example, the heating element 17) is used as shown in FIG. 3, by forming the silicon-based film layer 13 containing carbon on the base substrate 16 and then transferring it to the silicon substrate 12, the same effects as those described above can be obtained. When the heating element 17 is provided as the energy generating element as shown in FIG. 3, the diaphragm 9 and the cavity 10 are not formed on the substrate 4, and the heating element 17 is formed on the inner surface of the groove portion 7a formed in the substrate 4 or in the vicinity thereof.

[0020] The lower base plate 16 is not limited to a silicon substrate and may be a substrate made of other materials. However, if the lower base plate 16 is a single-crystalline silicon substrate, it is preferable because the film layer 13 can be easily formed by applying thin-film deposition techniques commonly used in semiconductor manufacturing methods. In addition, since the silicon-based lower base plate 16 is flat and has a small surface roughness, it has good bonding properties with the film layer 13, and the formation of the film layer 13 and the transfer to the silicon substrate 12 can be performed well, which is preferable.

Example

[0021] A specific example of the method for manufacturing a liquid ejection head of the present invention will be described. [Example 1] In Example 1 of the present invention, both the lower base plate 16 and the silicon substrate 12 are single-crystalline silicon substrates with a thickness of 625 μm, and the film layer 13 is made of a SiC film. First, as shown in FIG. 2(A), a SiC film layer was formed on one surface 16a of the lower base plate 16 by epitaxial growth. Specifically, at a temperature of 1600 ° C., a film layer 13 with a thickness of 1 μm and having crystals of 4H-SiC was formed on the lower base plate 16 by epitaxial growth. As shown in FIG. 2(B), the silicon substrate 12 was laminated on the film layer 13 on the lower base plate 16, and a plasma activation bonding method was performed by applying a force of 20 kN at a temperature of 300 ° C. to bond the film layer 13, the lower base plate 16, and the silicon substrate 12 to each other. As shown in FIG. 2(C), the silicon substrate 12 was ground or polished until the total thickness of the film layer 13 and the silicon substrate 12 became 100 μm (the thickness of the desired discharge port forming member 5). As shown in FIG. 2(D), DEEP-RIE (deep reactive ion etching) was performed on the silicon substrate 12 using the film layer 13 as a stop layer (etching stop layer) to form a through hole (preliminary hole portion 14) having a circular planar shape with a diameter of 100 μm.

[0022] As shown in Fig. 2(E), a substrate 4 on which a piezoelectric element 11, a diaphragm 9, a cavity 10, a supply path 6, and a groove 7a are formed is prepared. As shown in Fig. 2(F), the substrate 4 is laminated on the silicon substrate 12 on the side opposite to the underlying substrate 16 of a laminate (see Fig. 2(D)) composed of the silicon substrate 12, the film layer 13, and the underlying substrate 16. Then, the silicon substrate 12 and the substrate 4 are joined at a low temperature using an adhesive. By joining at a low temperature using an adhesive, damage to many various functional elements mainly formed on the substrate 4 was avoided. As shown in Fig. 2(G), the underlying substrate 16 is polished and removed to expose the film layer 13. At this time, the film layer 13 was used as a stop layer for polishing by utilizing the difference in the polishing rates between the silicon constituting the underlying substrate 16 and the SiC constituting the film layer 13. As shown in Fig. 2(H), RIE (Reactive Ion Etching) is performed on the film layer 13 to form a through hole (opening 15) having a circular planar shape with a diameter of 20 μm. The opening 15 and the lower hole 14 are concentrically arranged and communicate with each other to form the discharge port 8.

[0023] A liquid ink containing a pigment with a pH of about 8 to 9 was supplied to the element substrate 1 thus manufactured, and a simple storage test was conducted. As a result, it was found that neither a reduction in the thickness of the film layer 13 nor a deformation of the discharge port 8 occurred, and it had sufficient ink resistance. In this embodiment, since the film layer 13 is formed on the underlying substrate 16 by epitaxial growth that forms an SiC crystal with extremely few crystal defects, a discharge port forming member 5 with extremely few defects and extremely high mechanical strength can be formed in the film layer 13. In this embodiment, the opening 15 that constitutes the tip portion (the portion exposed to the outside) of the discharge port 8, which is particularly important, is composed of a silicon-based film layer 13 containing carbon with high resistance to various liquids. Thereby, the shape and dimensions of the tip portion of the discharge port 8 can be maintained with high precision, and good liquid discharge performance can be obtained.

[0024] As a modification of this embodiment, although not shown, an element substrate 1 with a film layer 13 having a thickness of 5 μm and an element substrate 1 with a film layer 13 having a thickness of 10 μm were also manufactured. Since the configuration and manufacturing method other than the thickness of the film layer 13 were not changed in these modifications, the description thereof is omitted. Even in these modifications, the same effects as those described above were obtained. Thus, according to this embodiment, the deformation due to the film stress of the film layer 13 was small, and it was possible to stably form the film layer 13 from a relatively thin film layer 13 to a relatively thick film layer 13 (for example, in the range where the film thickness is 1 μm or more and 10 μm or less).

[0025] [Example 2] In Example 2 of the present invention, only some of the steps in the manufacturing method of the liquid ejection head of Example 1 described above were changed, and the other steps are the same as those in Example 1, so the description thereof is omitted. In this example, although not shown, on one surface 16a of the base substrate 16, a film layer 13 made of an amorphous SiC film with a thickness of 3 μm was formed by performing PE-CVD at a temperature of 60°C. Then, grinding or polishing was performed so that the surface roughness of the surface of this film layer 13 (the surface to be joined to the silicon substrate 12) became 1 nm or less. Thereafter, in the same manner as in Example 1, the base substrate 16 having the film layer 13 and the silicon substrate 12 were joined to each other, the silicon substrate 12 was ground or polished to make it thinner, and a pilot hole 14 was formed in the silicon substrate 12. Further, in the same manner as in Example 1, the substrate 4 was laminated and joined to the silicon substrate 12, the base substrate 16 was polished and removed to expose the film layer 13, and an opening 15 was formed in the film layer 13.

[0026] When a simple storage test similar to that of Example 1 was conducted on the element substrate 1 thus manufactured, it was found that neither a reduction in the thickness of the film layer 13 nor a deformation of the discharge port 8 occurred, and that it had sufficient ink resistance. In this example, since the PE-CVD method is performed on the base substrate 16 at a relatively low temperature (60°C), even an amorphous film with poor crystallinity can suppress internal film stress. If the internal film stress is large, in the completed state of the discharge port 8, in the portion of the film layer 13 that is not supported by the silicon substrate 12 and protrudes toward the center of the discharge port 8 (membrane portion), a shrinkage deformation due to the internal film stress may occur, making it difficult to maintain the shape. However, in this example, by performing the PE-CVD method at a low temperature, the internal film stress can be reduced and deformation of the film layer 13 can be suppressed. Although the film formed by the PE-CVD method has a large surface roughness, in this example, since the surface of the film layer 13 is treated (ground or polished) to reduce the surface roughness, it can be satisfactorily joined to the silicon substrate 12.

[0027] If a thick film is formed as the film layer 13, the deformation of the element substrate 1 becomes large, and accordingly, there is a risk of hindering, for example, the smooth movement of the liquid ejection head or the smooth conveyance of the recording medium facing the liquid ejection head. However, in this example, since a thin film is formed as the film layer 13 and the internal film stress is reduced as described above, the deformation of the element substrate 1 can be suppressed and problems associated with the deformation can be avoided.

[0028] Thus, in this embodiment, by adjusting the temperature and performing surface treatment after film formation, a good film layer 13 can be formed by the PE-CVD method. Since the PE-CVD method can be implemented with a relatively simple and inexpensive apparatus, according to this embodiment, the production equipment of the element substrate 1 can be made into a simple and inexpensive structure, and the manufacturing cost of the liquid ejection head can be reduced. Epitaxial growth is crystal growth, and in order to adjust the film composition, another means such as ion doping is required, and it is not possible to easily adjust the film composition. On the other hand, in the PE-CVD method, since the formed film is an amorphous film, for silicon-based homogeneous films such as SiOC, SiCN, and SiOCN other than SiC, a desired film composition can be easily obtained only by changing the ratio of the material gas during film formation. However, due to the characteristics of the amorphous film, as described above, when the film stress is lowered to suppress deformation of the element substrate 1, there is an inverse relationship that the film density decreases. When the film density decreases, the strength of the film cannot be maintained and there is a possibility that film formation cannot be stably performed. Therefore, it is preferable that the film stress of the film layer 13 is a compressive stress of 800 Mpa or less and the film density is 1.5 g / cm 3 or more. For example, the film layer 13 of this embodiment is a SiC film with a compressive stress of 600 Mpa and a density of 2.3 g / cm 3 .

[0029] As a modification of this embodiment, although not shown, an element substrate 1 with a film layer 13 having a thickness of 5 μm was also manufactured. Since the configuration and manufacturing method other than the thickness of the film layer 13 are not changed in this modification, the description is omitted. Even in this modification, the same effects as described above were obtained. That is, even when the thickness of the film layer 13 of this embodiment fluctuates to a certain extent (for example, in the range of 1 μm or more and 10 μm or less as in Example 1), good effects were obtained.

[0030] [Example 3] In Example 3 of the present invention, a liquid ejection head shown in FIG. 4 was manufactured. In this liquid ejection head, an auxiliary film layer 18 is provided on the surface of the silicon substrate 12 on the side opposite to the film layer 13 and on the inner peripheral surface of the blind hole portion 14 where the blind hole portion 14 is formed. Therefore, in this embodiment, after forming the blind hole portion 14 in the silicon substrate 12, a step of forming the auxiliary film layer 18 is added.

[0031] That is, in this embodiment, as shown in FIG. 5(A), on one surface 16a of the base substrate 16 similar to that in Example 1, a film layer 13 made of an amorphous SiCN film with a thickness of 1.5 μm was formed by performing PE-CVD at a temperature of 60°C. Similar to Example 2, the surface of the film layer 13 was ground or polished to reduce the surface roughness. Then, as shown in FIG. 5(B), the base substrate 16 having the film layer 13 and the silicon substrate 12 were joined to each other. As shown in FIG. 5(C), the silicon substrate 12 was ground or polished to make it thinner. As shown in FIG. 5(D), a blind hole portion 14 was formed in the silicon substrate 12. Then, as shown in FIG. 5(E), by performing PE-CVD at a temperature of 60°C, an auxiliary film layer 18 made of a silicon-based film containing carbon, specifically an auxiliary film layer 18 made of a SiOC film with a thickness of 1.5 μm, was formed on the surface of the silicon substrate 12 excluding the surface in contact with the film layer 13. Thereafter, as shown in FIG. 5(G), the substrate 4 shown in FIG. 5(F) was laminated and joined to the silicon substrate 12 shown in FIG. 5(E). As shown in FIG. 5(H), the base substrate 16 was polished and removed to expose the film layer 13. Then, as shown in FIG. 5(I), RIE was performed to form an opening 15 penetrating the film layer 13. On the inner peripheral surface of the opening 15, there is a laminated structure with a total film thickness of 3.0 μm, which is composed of a film layer 13 made of an amorphous SiCN film with a thickness of 1.5 μm and an auxiliary film layer 18 made of a SiOC film with a thickness of 1.5 μm. The average carbon content of the laminated structure of the film layer 13 and the auxiliary film layer 18 is 5% or more, the film stress is a compressive stress of 800 Mpa or less, and the film density is 3 1.5 g / cm or more, and the total film thickness is 1 μm or more and 10 μm or less. The film stress of the film layer 13 made of the SiCN film in this embodiment is a compressive stress of 400 Mpa and the density is 2.4 g / cm 3 and the film stress of the auxiliary film layer 18 made of the SiOC film is a compressive stress of 200 Mpa and the density is 2.1 g / cm3 It was as described above. Except for the matters described above, since the configuration and manufacturing method of the liquid ejection head of this embodiment are the same as those of the liquid ejection head of Embodiment 2, the description thereof will be omitted.

[0032] When a simple storage test similar to that of Embodiment 1 was performed on the element substrate 1 of this embodiment, it was found that neither a reduction in the thickness of the film layer 13 and the auxiliary film layer 18 nor a deformation of the ejection port 8 occurred, and it had sufficient ink resistance. According to this embodiment, the inner peripheral surface of the ejection port 8 is formed by two overlapping films (the film layer 13 and the auxiliary film layer 18). According to this configuration, different functions can be imparted to the two films respectively. That is, in this embodiment, one film (the film layer 13) is a high-density film that maintains the strength of the ejection port forming member 5, and the other film (the auxiliary film layer 18) is a low-density film that relaxes the film stress. By using together a film that exhibits the function of maintaining strength and a film that exhibits the function of relaxing the film stress, it is possible to achieve both maintaining the strength particularly around the ejection port 8 and reducing the film stress to suppress deformation. The balance between the density and the film stress of the two films (the film layer 13 and the auxiliary film layer 18) can be appropriately set so as to obtain the desired strength and the deformation prevention effect. This is because since the auxiliary film layer 18 is in direct contact with the film layer 13, it is possible to add a function to the film layer 13. Thus, the laminated structure of the film layer 13 and the auxiliary film layer 18 constitutes the portion around the ejection port 8. As a result, it is possible to form the ejection port forming member 5 thinner while suppressing the internal film stress so that no deformation occurs particularly in the portion (membrane portion) that protrudes without being supported by the silicon substrate 12. And in this embodiment, the entire inner peripheral surface of the ejection port 8 (the inner peripheral surface of the opening 15 and the inner peripheral surface of the counterbore 14) is composed of a silicon-based film layer (the film layer 13 and the auxiliary film layer 18) containing carbon that has high resistance to various liquids. Therefore, the shape and dimensions of the entire ejection port 8 can be maintained with high precision, and good liquid ejection performance can be obtained.

[0033] As a modification of this embodiment, although not shown, an element substrate 1 having a film layer 13 made of a SiCN film with a thickness of 0.5 μm formed by the PE-CVD method and an auxiliary film layer 18 made of a SiOC film with a thickness of 0.5 μm formed by the PE-CVD method was also manufactured. The film stress of the film layer 13 made of the SiCN film is a compressive stress of 200 Mpa and the density is 2.0 g / cm 3 and the film stress of the auxiliary film layer 18 made of the SiOC film is a compressive stress of 100 Mpa and the density is 1.5 g / cm 3 and the thickness of the laminated film was 1.0 μm. In this modification, since the configuration and manufacturing method other than the film layer 13 and the auxiliary film layer 18 are not changed, the description is omitted. Also in this modification, the same effects as those described above were obtained. In this modification, for example, by forming the film layer 13 with a SiCN film containing 10% carbon in high-density SiN and forming the auxiliary film layer 18 with a SiOC film containing 10% carbon in low-density SiO, good effects were obtained even when the total film thickness of the laminated film was about 1 μm. Thus, in this embodiment, the film layer 13 and the auxiliary film layer 18 may form a laminated structure including at least two films among the SiC film, the SiOC film, the SiCN film, and the SiOCN film. When a plurality of auxiliary film layers 18 are provided, the functions of each layer can be further dispersed, and appropriate characteristics can be realized by appropriately combining the film thickness, density, and film stress of each.

[0034] In the above-described Examples 1 to 3, as shown in FIG. 3, it is also possible to adopt a configuration in which a heating element 17 is provided as an energy generating element. In that case, the diaphragm 9 and the cavity 10 are not formed on the substrate 4. Even with that configuration, the same effects as in Examples 1 to 3 can be exhibited.

[0035] (Method 1) A step of forming a silicon-based film layer containing carbon on one surface of a base substrate; A step of laminating a silicon substrate on the film layer formed on the one surface of the base substrate and bonding the silicon substrate to the film layer; A step of performing processing using the film layer as a stop layer on the silicon substrate bonded to the film layer to form a blind hole portion; A step of processing the lower base substrate using the film layer as a stop layer, removing the lower base substrate, and exposing the film layer; A step of forming an opening communicating with the lower hole portion in the exposed film layer; A method for manufacturing an element substrate of a liquid ejection head, characterized by including the above steps. (Method 2) The method for manufacturing an element substrate of a liquid ejection head according to Method 1, wherein the film layer is composed of at least one film selected from a SiC film, a SiOC film, a SiCN film, and a SiOCN film. (Method 3) The method for manufacturing an element substrate of a liquid ejection head according to Method 2, wherein a SiC film is formed as the film layer by epitaxial growth. (Method 4) The method for manufacturing an element substrate of a liquid ejection head according to Method 2, wherein an amorphous SiC film, a SiOC film, a SiCN film, or a SiOCN film is formed as the film layer by plasma-excited chemical vapor deposition. (Method 5) The method for manufacturing an element substrate of a liquid ejection head according to any one of Methods 1 to 4, further including a step of providing a silicon-based auxiliary film layer containing carbon on a surface of the silicon substrate opposite to the film layer and an inner peripheral surface of the lower hole portion. (Method 6) The method for manufacturing an element substrate of a liquid ejection head according to Method 5, wherein the lower hole portion and the opening are concentrically arranged and communicate to form a discharge port, and an inner peripheral surface of the discharge port is composed of the film layer and the auxiliary film layer. (Method 7) The method for manufacturing an element substrate of a liquid ejection head according to Method 5 or 6, wherein the film layer and the auxiliary film layer form a laminated structure including at least two films selected from a SiC film, a SiOC film, a SiCN film, and a SiOCN film. (Method 8) A substrate having a groove portion constituting a liquid flow path, a supply path for supplying liquid to the flow path, and an energy generating element for applying ejection energy to the liquid in the flow path is laminated on the silicon substrate, and the flow path and the lower hole portion are communicated with each other. The method for manufacturing an element substrate of a liquid ejection head according to any one of Methods 1 to 7. (Method 9) The energy generating element is a piezoelectric element. The substrate further includes a flexible diaphragm that forms a part of the wall of the flow path on the side opposite to the silicon substrate side, and a hollow cavity portion provided on the side opposite to the flow path with the diaphragm interposed therebetween. The method for manufacturing an element substrate of a liquid ejection head according to Method 8. (Method 10) A method for manufacturing a liquid ejection head, including each step of the method for manufacturing an element substrate of a liquid ejection head according to Method 8 or 9, a step of connecting an electrical wiring member to the energy generating element, and a step of connecting a liquid container to the supply path. (Configuration 1) A substrate having a groove portion forming a flow path for a liquid, a supply path for supplying the liquid to the flow path, and an energy generating element for imparting ejection energy to the liquid in the flow path, and a discharge port forming member having a discharge port communicating with the flow path and laminated on the substrate. The element substrate of the liquid ejection head includes: The discharge port forming member includes a silicon substrate and a film layer provided on the surface of the silicon substrate. A through hole penetrating the silicon substrate and an opening penetrating the film layer communicate with each other to form the discharge port. The film layer is a silicon-carbon-based film layer containing carbon, with a carbon content of 5% or more, a film stress of 800 Mpa or less in compressive stress, a film density of 1.5 g / cm 3 or more, and a film thickness of 1 μm or more and 10 μm or less. The element substrate of the liquid ejection head is characterized by this. (Configuration 2) A substrate having a groove portion forming a flow path for a liquid, a supply path for supplying the liquid to the flow path, and an energy generating element for imparting ejection energy to the liquid in the flow path, and a discharge port forming member having a discharge port communicating with the flow path and laminated on the substrate. The element substrate of the liquid ejection head includes: The discharge port forming member includes a silicon substrate and a film layer provided on the surface of the silicon substrate. A through hole penetrating the silicon substrate and an opening penetrating the film layer communicate with each other to form the discharge port. An auxiliary film layer is provided on the surface of the silicon substrate opposite to the film layer and on the inner peripheral surface of the through hole. Both the film layer and the auxiliary film layer are made of a silicon-carbon-based film layer containing carbon. The average carbon content of the laminated structure of the film layer and the auxiliary film layer is 5% or more, the film stress is a compressive stress of 800 Mpa or less, the film density is 1.5 g / cm 3 or more, and the total film thickness is 1 μm or more and 10 μm or less. The element substrate of the liquid ejection head is characterized by this. (Configuration 3) The laminated structure of the film layer and the auxiliary film layer includes at least two films among SiC film, SiOC film, SiCN film, and SiOCN film. The element substrate of the liquid ejection head according to Configuration 2. (Configuration 4) The film layer is a SiC film having a crystal structure. The element substrate of the liquid ejection head according to any one of Configurations 1 to 3. (Configuration 5) The film layer is an amorphous SiC film, SiOC film, SiCN film, or SiOCN film. The element substrate of the liquid ejection head according to any one of Configurations 1 to 4. (Configuration 6) The liquid ejection head includes the element substrate of the liquid ejection head according to any one of Configurations 1 to 5, an electrical wiring member connected to the energy generating element, and a liquid container connected to the supply path.

Explanation of Signs

[0036] 1 Element substrate 8 Nozzle 12 Silicon substrate 13 Film layer 14 Through hole part 15 Opening 16 Bottom substrate

Claims

1. A step of forming a silicon-based film layer containing carbon on one surface of a lower base plate; A step of laminating a silicon substrate on the film layer formed on the one surface of the lower base plate and bonding the silicon substrate to the film layer; A step of performing processing using the film layer as a stop layer on the silicon substrate bonded to the film layer to form a lower hole portion; A step of performing processing using the film layer as a stop layer on the lower base plate, removing the lower base plate, and exposing the film layer; A step of forming an opening communicating with the lower hole portion in the exposed film layer; A method for manufacturing an element substrate of a liquid ejection head, characterized by including the above steps.

2. The method for manufacturing an element substrate of a liquid ejection head according to Claim 1, wherein the film layer is composed of at least one film selected from an SiC film, an SiOC film, an SiCN film, and an SiOCN film.

3. The method for manufacturing an element substrate of a liquid ejection head according to Claim 2, wherein an SiC film is formed as the film layer by epitaxial growth.

4. The method for manufacturing an element substrate of a liquid ejection head according to Claim 2, wherein an amorphous SiC film, SiOC film, SiCN film, or SiOCN film is formed as the film layer by plasma-excited chemical vapor deposition.

5. The method for manufacturing an element substrate of a liquid ejection head according to Claim 1, further including a step of providing a silicon-based auxiliary film layer containing carbon on a surface of the silicon substrate opposite to the film layer and an inner peripheral surface of the lower hole portion.

6. The method for manufacturing an element substrate of a liquid ejection head according to Claim 5, wherein the lower hole portion and the opening are concentrically arranged and communicate to form a discharge port, and an inner peripheral surface of the discharge port is composed of the film layer and the auxiliary film layer.

7. The method for manufacturing an element substrate of a liquid ejection head according to Claim 5 or 6, wherein the film layer and the auxiliary film layer constitute a laminated structure including at least two films selected from an SiC film, an SiOC film, an SiCN film, and an SiOCN film.

8. A substrate having a groove portion forming a liquid flow path, a supply path for supplying liquid to the flow path, and an energy generating element for imparting ejection energy to the liquid in the flow path is laminated on the silicon substrate, and the flow path is communicated with the lower hole portion. The method for manufacturing an element substrate of a liquid ejection head according to Claim 1.

9. The energy generating element is a piezoelectric element. The substrate further includes a flexible diaphragm that forms a part of the wall of the flow path on the side opposite to the silicon substrate side, and a hollow cavity portion provided on the side opposite to the flow path with the diaphragm interposed therebetween, in the method for manufacturing an element substrate of a liquid ejection head according to claim 8.

10. A method for manufacturing a liquid ejection head, including each step of the method for manufacturing an element substrate of a liquid ejection head according to claim 8 or 9, a step of connecting an electrical wiring member to the energy generating element, and a step of connecting a liquid container to the supply path.

11. A substrate having a groove portion constituting a flow path for liquid, a supply path for supplying liquid to the flow path, and an energy generating element for imparting ejection energy to the liquid in the flow path, and a discharge port forming member having a discharge port communicating with the flow path and laminated on the substrate, wherein the discharge port forming member includes a silicon substrate and a film layer provided on the surface of the silicon substrate, and a lower hole portion penetrating the silicon substrate and an opening portion penetrating the film layer communicate with each other to form the discharge port. The film layer is a silicon-based film layer containing carbon, with a carbon content of 5% or more, a film stress of compressive stress of 800 Mpa or less, a film density of 1.5 g / cm 3 or more, and a film thickness of 1 μm or more and 10 μm or less. The element substrate of the liquid ejection head is characterized by this.

12. A substrate having a groove portion constituting a flow path for liquid, a supply path for supplying liquid to the flow path, and an energy generating element for imparting ejection energy to the liquid in the flow path, and a discharge port forming member having a discharge port communicating with the flow path and laminated on the substrate, wherein the discharge port forming member includes a silicon substrate and a film layer provided on the surface of the silicon substrate, and a lower hole portion penetrating the silicon substrate and an opening portion penetrating the film layer communicate with each other to form the discharge port. An auxiliary film layer is provided on the surface of the silicon substrate on the side opposite to the film layer and on the inner peripheral surface of the lower hole portion. Both the film layer and the auxiliary film layer are made of a silicon-based film layer containing carbon. The average carbon content of the laminated structure of the film layer and the auxiliary film layer is 5% or more, the film stress is a compressive stress of 800 Mpa or less, the film density is 1.5 g / cm 3 or more, and the total film thickness is 1 μm or more and 10 μm or less. The element substrate of the liquid ejection head is characterized by this.

13. The laminated structure of the film layer and the auxiliary film layer includes at least two films among SiC film, SiO C film, SiC N film, and SiO C N film, in the element substrate of a liquid ejection head according to claim 12.

14. The film layer is a crystalline SiC film, in the element substrate of a liquid ejection head according to claim 11 or 12.

15. The film layer is an amorphous SiC film, SiO C film, SiC N film, or SiO C N film, in the element substrate of a liquid ejection head according to claim 11 or 12.

16. A liquid ejection head comprising: an element substrate of the liquid ejection head according to claim 11 or 12; an electrical wiring member connected to the energy generating element; and a liquid container connected to the supply path.

Images