Multilayer substrate, liquid dispensing head

Abstract

To provide a laminate substrate in which variation in hole diameter is suppressed at a boundary between a silicon substrate and a silicon oxide film.SOLUTION: A laminate substrate includes a silicon substrate 20, and a silicon compound film 110 laminated on the silicon substrate 20. The silicon compound film 110 has an open hole 115, and the silicon substrate 20 has a hole 135 communicating with the open hole 115. In at least a part of the hole 135 in a depth direction, the diameter of the hole 135 is made to be smaller than the diameter of the open hole 115 on a surface contacting the silicon substrate 20, thereby realizing a laminate substrate in which variation in hole diameter is suppressed.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a laminated substrate, a liquid ejection head, and a method for manufacturing a laminated substrate.

Background Art

[0002] As a liquid ejection head used in an inkjet printer or the like, Patent Document 1 describes one in which liquid ejection holes are formed in a single crystal silicon substrate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] With the progress of atomization of the ejection liquid in the liquid ejection head, the diameter of the liquid ejection holes has been reduced and the thickness of the substrate for forming the ejection ports has been reduced. In such a situation, it has been found that the finish of the side surface of the liquid ejection holes greatly affects the ejection performance. To improve the finish of the side surface of the liquid ejection holes, there is a method of forming a silicon oxide film on the surface of the silicon substrate described in Patent Document 1. However, the silicon oxide film is likely to cause a change in the diameter of the liquid ejection holes at the boundary with the silicon substrate, which may increase the flow path resistance of the liquid ejection holes. Further, not limited to the application to the liquid ejection head, when providing holes in a laminated substrate of a silicon substrate and a silicon oxide film, it is preferable to suppress a change in the diameter of the holes at the boundary between the silicon substrate and the silicon oxide film as much as possible.

[0005] An object of the present invention is to provide a laminated substrate in which a change in the diameter of a hole at the boundary between a silicon substrate and a silicon oxide film is suppressed, and a method for manufacturing the same.

Means for Solving the Problems

[0006] To achieve the above objective, according to one aspect of the present invention, the present invention comprises a silicon substrate and a silicon compound film laminated on the silicon substrate, wherein the silicon compound film has through holes through which liquid passes, and the silicon substrate has holes through which liquid passes and which communicate with the through holes, the through holes are located downstream of the holes in the direction of liquid discharge, and at least a portion of the depth direction of the holes has a diameter smaller than the diameter of the through holes on the surface in contact with the silicon substrate. Ku , The diameter of the through-holes increases monotonically as you move away from the interface between the silicon compound film and the silicon substrate. A multilayer substrate is provided.

[0007] According to another aspect of the present invention, a method for manufacturing a laminated substrate having a silicon substrate and a silicon compound film laminated on the silicon substrate, wherein the silicon compound film of the laminated substrate Liquid passes through The steps include forming through holes and, on the silicon substrate, Liquid passes through The step includes forming holes that communicate with through-holes in a silicon compound film, The through-hole is located downstream of the hole in the direction of liquid discharge. A method for manufacturing a laminated substrate is provided, comprising the step of forming through holes in which by-products are generated, a portion of which adheres to the side walls of the through holes in the silicon compound film, the step of forming the holes being carried out with the by-products adhering to the side walls of the through holes, and the step of removing the by-products after the formation of the through holes and holes. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a laminated substrate and a method for manufacturing the same in which changes in the diameter of holes at the boundary between the silicon substrate and the silicon oxide film are suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view showing the configuration of a liquid dispensing head according to one embodiment of the present invention. [Figure 2] Figure 1 is a partial cross-sectional view of the laminated substrate of the liquid dispensing head shown in Figure 1. [Figure 3] This is a partial cross-sectional view showing the liquid discharge hole formation process according to a comparative example. [Figure 4] This is a partial cross-sectional view showing the process of forming a liquid discharge hole according to an embodiment of the present invention. [Figure 5] This is a partial cross-sectional view showing the shape of the liquid discharge hole that may occur in the embodiment. [Figure 6] This is a partial cross-sectional view showing a modified example. [Modes for carrying out the invention]

[0010] A laminated substrate 111 according to one embodiment of the present invention will be described with reference to Figures 1 to 5. This embodiment is illustrative of the present invention and is not intended to limit the scope of the present invention to this embodiment. The laminated substrate of the embodiment shown below is applied to a liquid ejection head using a piezoelectric element, but it can also be applied to a liquid ejection head using a heat-generating resistance element or an electrothermal conversion element. The ejected liquid is not limited to ink as long as it can be ejected from the liquid ejection head.

[0011] In the following description and diagrams, the Z direction refers to the direction in which the silicon substrate and the silicon compound film (silicon oxide film) are stacked, or the depth direction of the through hole or hole. Any direction perpendicular to the Z direction is called the X direction. A direction perpendicular to both the Z and X directions is called the Y direction. The diameter refers to the dimension in the XY plane, and the radial direction refers to the direction from the central axis of the hole toward the outer circumference of the hole in the XY plane. In the case of a hole or through hole with a circular cross-section, the diameter is equal to the diameter in the XY plane.

[0012] (Configuration of the liquid dispensing head) Figure 1 is a cross-sectional view showing a main part (partial) of the ink ejection head 1 of a printer after manufacturing according to one embodiment of the present invention. The actuator substrate 10a is made of silicon. The actuator substrate 10a supports the vibrating membrane 60 via a protective film 40 and an insulating film 50. The vibrating membrane 60 is bonded to the insulating film 70. The insulating film 70 forms one surface of the cavity 80 and, together with the connection part 10b and the silicon substrate 20, defines the cavity 80. Ink is supplied to the cavity 80 through a through hole 30 that penetrates the actuator substrate 10a in the Z direction, and through a liquid channel 35 that penetrates the protective film 40, the insulating film 50, the vibrating membrane 60, and the insulating film 70 in the Z direction. A piezoelectric element 45 is arranged between the protective film 40 and the insulating film 50. A cavity 85 is formed on the side of the protective film 40 opposite to the piezoelectric element 45. The silicon substrate 20 and the silicon compound film 110 form a laminated substrate 111. The silicon substrate 20 has a liquid ejection hole 90 that communicates with the cavity 80. An ink ejection port 100 is formed at the downstream end of the liquid ejection hole 90 in the ejection direction. The diameter of the ejection port 100 is determined by the amount of ink to be ejected and is generally about 5 μm to 50 μm. By applying a drive voltage from a power supply (not shown) to the piezoelectric element 45, the vibrating membrane 60 vibrates, and the cavity 80 repeatedly expands and contracts. As the ink inside the cavity 80 is pressurized, the ink passes through the liquid ejection hole 90 and is ejected from the ejection port 100.

[0013] (Shape and composition of the liquid discharge port) Figure 2 is an enlarged view of part A in Figure 1, showing a partial cross-sectional view of the laminated substrate 111. Figure 2(a) shows the silicon compound film 110 and the through-holes 115 in the silicon compound film 110, as well as the silicon substrate 20 and the through-holes 135 in the silicon substrate 20 in this embodiment. At any position in the Z direction, the cross-sections of the through-holes 115 and 135 are approximately circular. The through-hole 115 communicates with the through-hole 135 to form the liquid discharge hole 90. The central axes of the through-holes 115 and 135 are roughly coincide. The silicon compound film 110 is composed of SiO, SiO2, Si3N4, and SiN xIt is preferable to contain one or more of SiC, SiON, SiOC, SiCN, SiOCN, and it is particularly preferable that it is a silicon oxide film. In the present embodiment, the silicon compound film 110 will be described assuming that it is a silicon oxide film. The through-hole 135 of the silicon substrate 20 is an example of a hole, and the hole may be a concave portion having a bottom. The through-hole 135 is formed by a Bosch process of the silicon substrate 20 using the silicon compound film 110 as a mask. The Bosch process refers to a dry etching process that repeats isotropic etching, formation of a sidewall protection film, and anisotropic etching.

[0014] The diameter of the through-hole 115 monotonically increases in the silicon oxide film 110 as it moves away from the interface with the silicon substrate 20. Since the silicon oxide film 110 is located outside the silicon substrate 20, that is, on the downstream side in the ink ejection direction, at least the downstream side of the liquid ejection hole 90 has a relatively smooth tapered side surface. A protruding portion 120 that protrudes inside the through-hole 135 is formed at the interface between the silicon substrate 20 and the silicon oxide film 110. The protruding portion 120 is made of silicon.

[0015] FIG. 2(b) shows the silicon compound film 110, the through-hole 117 of the silicon compound film 110, the silicon substrate 20, and the through-hole 137 of the silicon substrate 20 in the comparative example. The through-hole 117 communicates with the through-hole 137 to form a liquid ejection hole 150. The central axes of the through-hole 117 and the through-hole 137 are generally coincident. The through-hole 137 is formed by a Bosch process of the silicon substrate 20 as in the example. In the comparative example, the side etching amount of the silicon substrate 20 directly below the silicon compound film 110 is large, and a large protruding portion 140 of the silicon oxide film is formed. The side etching amount refers to the etching amount in the radial direction. Since the protruding portion 140 hardly changes even if the Bosch process is continued, it causes an increase in the liquid path resistance of the liquid ejection hole. Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples.

[0016] (Comparative Example) Figure 3 shows the formation process of the liquid discharge hole 150 of the comparative example. The diameter of the discharge hole was made into a circle with a diameter of φ20 μm. First, as shown in Fig. 3(a), a photoresist was applied, and a resist mask 160 was provided on the oxide film 110 in which a pattern of through holes 117 to be formed was formed by photolithography.

[0017] Next, as shown in Fig. 3(b), the silicon oxide film 110 was etched through the resist mask 160 to form through holes 117 in the silicon oxide film 110. Generally, the etching of the silicon oxide film is performed using a mixed gas of C4F8 gas (octafluorocyclobutane gas), CF4 gas, and Ar gas. At this time, after the formation of the through holes 117, the by-products 170 invade the through holes 117 and accumulate on the bottom of the through holes 117, that is, on the silicon substrate 20. The by-products 170 mean those formed by mixing etching by-products and a deposited film containing carbon and fluorine. The C4F8 gas is used to enhance the straightness of the etching of the silicon oxide film 110. However, in the comparative example, for the purpose of explaining the effects of the examples, the C4F8 gas was not used. That is, the etching gas was a mixed gas of CF4 gas and Ar gas that does not contain C4F8 gas.

[0018] The conditions for the etching of the silicon oxide film 110 were as follows. In general, in the etching of the silicon oxide film 110, the pressure of the etching gas is controlled in the range of 0.1 Pa to 5 Pa, the flow rate of the etching gas is controlled in the range of 10 sccm to 1000 sccm, and the power applied to the coil is controlled in the range of 1000 W to 2000 W. In the comparative example, the pressure of the etching gas, which is a mixed gas of CF4 gas and Ar gas, was 0.3 Pa, the flow rate of the etching gas was 200 sccm, and the power applied to the coil was 1500 W. It was confirmed in a test different from the comparative example that the film thickness of the by-products 170 in the comparative example was small and below the measurement limit.

[0019] Next, as shown in Figure 3(c), the Bosch process was performed until through-holes 137 were formed in the silicon substrate 20 through the resist mask 160 and through-holes 117. SF6 gas was used as the etching gas and C4F8 gas as the coating gas. After that, as shown in Figure 3(d), the resist mask 160 was removed. The diameter of the liquid discharge hole 150 in the silicon substrate 20 became larger than the diameter of the opening at the interface between the through-hole 117 in the silicon oxide film 110 and the silicon substrate 20. In other words, the cross-sectional area of ​​the liquid discharge hole 150 in the silicon substrate 20 became larger than the cross-sectional area of ​​the opening at the interface between the silicon oxide film 110 and the silicon substrate 20. As a result, a protrusion 140 was formed. The radial length of the protrusion 140 was about a few μm. However, especially when the diameter of the liquid discharge hole 150 in the silicon substrate 20 is about 50 μm or less and a high-viscosity liquid is discharged, the protrusion 140 causes an increase in the flow resistance of the liquid discharge hole 150. This increased flow resistance affects the meniscus oscillation of the liquid, making liquid discharge unstable.

[0020] The conditions for the Bosch process were as follows: In the Bosch process, SF6 gas is generally used as the etching gas and C4F8 gas as the protective film coating gas. In the etching and protective film formation processes, the gas pressure is controlled in the range of 0.1 Pa to 50 Pa, and the gas flow rate is controlled in the range of 50 sccm to 1000 sccm. The etching process time is controlled between 5 seconds and 20 seconds, and the protective film formation process time is controlled between 1 second and 10 seconds. To increase the etching rate in order to shorten the required time, the gas pressure should be 10 Pa or more, the gas flow rate should be 500 sccm or more, and the etching step time should be 5 seconds or more. In the comparative example, SF6 gas and C4F8 gas were used, similar to the general Bosch process, and the gas pressure was controlled to 10 Pa, the gas flow rate to 700 sccm, the etching step time to 10 seconds, and the coating step time to 5 seconds, forming a highly vertical flow path.

[0021] (Examples) Figure 4 shows the process of forming the liquid discharge holes 90 according to the embodiment. The diameter of the discharge holes was set to be a circle with a diameter of φ20 μm. First, as shown in Figure 4(a), a resist mask 165 was provided on which a pattern of through holes 115 to be formed in the oxide film 110 was formed, similar to Figure 3(a).

[0022] Next, as shown in Figure 4(b), the silicon oxide film 110 was etched through the resist mask 165 to form through-holes 115 in the silicon oxide film 110. To facilitate the generation of by-products 171, the flow rate of C4F8 gas contained in the etching gas was set to 100 sccm. As a result, a larger amount of by-products 171 than the by-products 170 shown in Figure 3(b) was deposited on the silicon substrate 20, the resist mask 165, the side walls of the silicon oxide film 110, and on the resist mask 165. The etching conditions for the silicon oxide film in this example were: etching gas pressure of 0.3 Pa, etching gas flow rate of 200 sccm, and power applied to the coil of 1500 W. The flow rate of C4F8 gas in the etching gas was set to 100 sccm as described above. Note that increasing the flow rate of C4F8 gas above 100 sccm has little effect. Generally, in order to increase the amount of by-product 171 produced, it is preferable to maintain a flow rate of C4F8 gas between 30 sccm and 100 sccm throughout the entire through-hole 115.

[0023] Next, as shown in Figure 4(c), through-holes 137 were formed in the silicon substrate 20 by the Bosch process. In this example, as with general manufacturing methods, SF6 gas and C4F8 gas were used, with a gas pressure of 3 Pa, a gas flow rate of 300 sccm, an etching process time of 3 seconds, and a protective film formation process time of 1 second to form a highly vertical flow path. At this time, the by-products 171 adhering to the upper surface of the resist mask 165 and the upper surface of the silicon substrate 20 are removed, but the by-products 171 adhering to the side walls of the resist mask 165 and the silicon oxide film 110 remain (hereinafter referred to as the side wall residue portion 175). The side wall residue portion 175 prevents the gas for etching the silicon substrate 20 from coming into contact with the surface of the silicon substrate 20. If the radial thickness of the side wall residue portion 175 is large, the diameter of the liquid discharge hole 90 directly below the side wall residue portion 175 becomes smaller. Therefore, the radial length of the protrusion 140 (see Figure 3) can be reduced, or even made zero.

[0024] Next, as shown in Figure 4(d), the resist mask 165 and the residual sidewall portion 175 were removed. A protrusion 120 of the silicon substrate was formed at the interface between the silicon substrate 20 and the silicon oxide film 110. The length of the protrusion 120 was approximately 0.1 μm or more.

[0025] Generally, when holes are formed in a silicon substrate using the Bosch process, a periodic concave structure is created in which multiple recesses called scallops are arranged in a continuous sequence in the depth direction Z. To explain the shape of the scallops, the dimensions are defined as follows (see Figure 2). L1 (Scallop period): The length in the Z direction of each individual recess among the continuous recesses formed on the side walls of the liquid discharge holes 90 and 150 of the silicon substrate 20. L2 (Scallop Amplitude): The maximum radial depth of each individual recess among the continuous recesses formed on the side walls of the liquid discharge holes 90 and 150 of the silicon substrate 20. In both the comparative example and the example, the Bosch process was controlled so that the shape of each scallop was uniform, and L1 and L2 were nearly constant. In the comparative example, the side wall shape of the liquid discharge hole 150 had a scallop period L1 of approximately 5 μm and a scallop amplitude L2 of approximately 1 μm, as shown in Figure 2(b). In the example, the side wall shape of the liquid discharge hole 90 had a scallop period L1 of approximately 0.4 μm and a scallop amplitude L2 of approximately 0.1 μm, as shown in Figure 2(a).

[0026] As a result of the reduction in scalloping in the embodiment described above, the maximum diameter W1 of the liquid discharge holes 90 in the silicon substrate 20 is smaller than the diameter W2 of the liquid discharge holes 90 on the surface of the silicon oxide film 110 that contacts the silicon substrate 20, or the maximum cross-sectional area of ​​the liquid discharge holes 90 in the silicon substrate 20 is smaller than the minimum cross-sectional area of ​​the liquid discharge holes 90 in the silicon oxide film 110. The advantages of this are described below.

[0027] The liquid ejection head has numerous liquid ejection holes 90. For good liquid ejection, it is desirable to combine the design tolerances and ensure that the overall shape of each liquid ejection hole 90 is within a certain tolerance range. As the scallop size decreases, the sum of the tolerances decreases. An example of a parameter related to the overall shape is the diameter of the liquid ejection holes 90 on the surface of the silicon oxide film 110 that contacts the silicon substrate 20. The variation in diameter between the liquid ejection holes 90 decreases as the scallop size decreases. As a result, the flow resistance decreases in each liquid ejection hole 90 and the meniscus vibration stabilizes, which is expected to stabilize the supply of ink to the entire liquid ejection head even when the ejection interval is short, and improve the refill performance of ink to the liquid ejection holes 90 for continuous ejection. According to the example, good results were obtained in a test to eject ink onto a recording medium without gaps, and compared to the comparative example, stabilization of liquid ejection and improvement in print quality were achieved.

[0028] Furthermore, the through-holes 90 in the silicon substrate 20 are not limited to having a uniform cross-sectional shape extending perpendicularly from the substrate surface. For example, as shown in Figure 5(a), the diameter of the liquid discharge holes 200 in the silicon substrate 20 may be formed to increase as it moves away from the silicon oxide film 110 in the Z direction. Also, as shown in Figure 5(b), the liquid discharge holes 210 in the silicon substrate 20 may be formed such that their central axis is not perpendicular to the interface between the silicon substrate 20 and the silicon oxide film 110. In both of these cases, it was confirmed that the characteristic features of the embodiment—that the protrusion 140 is eliminated and a protrusion 120 is formed by the residual side wall portion 175—and that the printing effect of the embodiment remains unchanged.

[0029] (modified version) Figure 6 shows the process of forming the liquid discharge holes 220 by a modified example. First, as shown in Figure 6(a), a resist mask 167 was provided on which a pattern of through-holes to be formed in the oxide film 110 was formed, similar to Figure 4(a).

[0030] Next, in this modified example, as shown in Figure 6(b), the silicon oxide film 110 was etched through the resist mask 167 to form through-holes 118 in the silicon oxide film 110. The etching conditions for the silicon oxide film 110 used in this modified example were a pressure of 0.3 Pa for the etching gas, which is a mixed gas of C4F8 gas, CF4 gas, and Ar gas; a flow rate of 200 sccm of etching gas (including a flow rate of 30 sccm of C4F8 gas); and a power applied to the coil of 1500 W. By-products 172 were deposited on the silicon substrate 20, on the resist mask 167 and the sidewalls of the silicon oxide film 110, and on the resist mask 167, but the amount of deposition was less than in the case of by-product 171 shown in Figure 4(b). This is because the flow rate of C4F8 gas was reduced from 100 sccm to 30 sccm.

[0031] Next, as shown in Figure 6(c), through holes 138 were formed in the silicon substrate 20 by the Bosch process. In the modified example, SF6 gas and C4F8 gas were used, the gas pressure was 10 Pa, the gas flow rate was 500 sccm, the etching process time was 6 seconds, and the protective film formation process time was 3 seconds to form a highly vertical channel. In this case, the by-products 172 adhering to the upper surface of the resist mask 167 and the upper surface of the silicon substrate 20 were removed, but the by-products 172 adhering to the resist mask 167 and the sidewalls of the silicon oxide film 110 remained, becoming the sidewall residue portion 176. The scallop on the side of the silicon substrate 20 of the liquid discharge hole 220 had a scallop period L1 of 0.8 μm and a scallop amplitude L2 of 0.2 μm, which is larger than the scallop on the side of the silicon substrate 20 of the liquid discharge hole 90 in the example, but smaller than the scallop on the side of the silicon substrate 20 of the liquid discharge hole 150 in the comparative example.

[0032] Next, as shown in Figure 6(d), the resist mask 167 and the sidewall residue portion 176 were removed. A protrusion 121 of the silicon substrate is formed at the interface between the silicon substrate 20 and the silicon oxide film 110. Since the radial length of the sidewall residue portion 176 is smaller than the radial length of the sidewall residue portion 175, the radial length of the protrusion 121 is smaller than the radial length of the protrusion 120, and is approximately 0.1 μm or less. The maximum diameter W5 of the liquid discharge hole 220 of the silicon substrate 20 is larger than the minimum diameter W4 of the liquid discharge hole 220 of the silicon oxide film 110, and the minimum diameter W3 of the liquid discharge hole 220 of the silicon substrate 20 is smaller than the minimum diameter W4 of the liquid discharge hole 220 of the silicon oxide film 110. Alternatively, the maximum cross-sectional area of ​​the liquid discharge holes 220 in the silicon substrate 20 is greater than the minimum cross-sectional area of ​​the liquid discharge holes 220 in the silicon oxide film 110, and the minimum cross-sectional area of ​​the liquid discharge holes 220 in the silicon substrate 20 is smaller than the minimum cross-sectional area of ​​the liquid discharge holes 220 in the silicon oxide film 110. In other words, with respect to the diameter or cross-sectional area of ​​the through-holes of the liquid discharge holes 220 in the silicon substrate 20, there are dimensional tolerances in both the larger and smaller directions compared to the openings in the silicon oxide film 110 at the interface with the silicon substrate 20.

[0033] Ink ejection tests were conducted using the liquid ejection holes 220 shown in Figure 6(d). The results showed improved meniscus vibration stability, improved ink ejection stability, and improved print quality compared to the comparative example using liquid ejection holes 150. However, since the scallops in the example are smaller than those in this modified example, these effects are better in the example. Because the modified example has larger scallops than the example, fewer cycles are required to form individual scallops in order to create through-holes 138 in the silicon substrate 20. Therefore, it is advantageous in that the process of forming through-holes 138 is simpler and quicker.

[0034] The disclosure of embodiments of the present invention includes the following configurations and methods. (Composition 1) It comprises a silicon substrate and a silicon compound film laminated on the silicon substrate, The silicon compound film has through holes, The silicon substrate has a hole that communicates with the through hole, A laminated substrate in which, in at least a portion of the depth direction of the hole, the diameter of the hole is smaller than the diameter of the through hole on the surface in contact with the silicon substrate. (Configuration 2) It comprises a silicon substrate and a silicon compound film laminated on the silicon substrate, The silicon compound film has through holes, The silicon substrate has a hole that communicates with the through hole, A laminated substrate in which, in at least a portion of the depth direction of the hole, the cross-sectional area of ​​the hole is smaller than the cross-sectional area of ​​the through hole on the surface in contact with the silicon substrate. (Composition 3) The laminated substrate according to configuration 1 or 2, wherein the aforementioned hole is a through-hole penetrating the silicon substrate. (Composition 4) The silicon compound film is SiO, SiO2, Si3N4, SiN x A laminated substrate according to any one of configurations 1 to 3, comprising one or more of SiC, SiON, SiOC, SiCN, and SiCN. (Composition 5) The laminated substrate according to any one of the three configurations, wherein the silicon compound film is a silicon oxide film. (Composition 6) A laminated substrate according to any one of configurations 1 to 5, wherein, throughout the entire depth of the hole, the diameter of the hole is smaller than the diameter of the through-hole on the surface in contact with the silicon substrate. (Composition 7) A laminated substrate according to any one of configurations 1 to 6, wherein in a portion of the hole in the depth direction, the diameter of the hole is smaller than the diameter of the through hole on the surface in contact with the silicon substrate. (Composition 8) A liquid dispensing head comprising a laminated substrate according to any one of claims 1 to 7. (Method 1) A method for manufacturing a laminated substrate having a silicon substrate and a silicon compound film laminated on the silicon substrate, The steps include forming through holes in the silicon compound film of the laminated substrate, The step of forming holes in the silicon substrate that communicate with the through-holes of the silicon compound film, In the step of forming the through-hole, a by-product is generated, and a portion of the by-product adheres to the side wall of the through-hole in the silicon compound film. The step of forming the hole is performed with the by-product adhering to the side wall of the through hole. A method for manufacturing a laminated substrate, further comprising the step of removing the by-product after the formation of the through-holes and the holes. (Method 2) The silicon compound film is SiO, SiO2, Si3N4, SiN x A method for manufacturing a laminated substrate according to Method 1, comprising one or more of SiC, SiON, SiOC, SiCN, and SiCN. (Method 3) The method for manufacturing a laminated substrate according to Method 1, wherein the silicon compound film is a silicon oxide film. (Method 4) The holes in the silicon substrate are formed by dry etching, which involves repeatedly performing isotropic etching, forming a sidewall protective film, and anisotropic etching. A method for manufacturing a laminated substrate according to any one of methods 1 to 3, wherein in at least a portion of the depth direction of the hole, the diameter of the hole is smaller than the diameter of the through hole on the surface in contact with the silicon substrate. (Method 5) The holes in the silicon substrate are formed by dry etching, which involves repeatedly performing isotropic etching, forming a sidewall protective film, and anisotropic etching. A method for manufacturing a laminated substrate according to any one of methods 1 to 4, wherein in at least a portion of the depth direction of the hole, the cross-sectional area of ​​the hole is smaller than the cross-sectional area of ​​the through hole on the surface in contact with the silicon substrate. (Method 6) A method for manufacturing a laminated substrate according to any one of methods 1 to 5, wherein the through-holes in the silicon compound film are formed by etching using a gas containing octafluorocyclobutane gas. (Method 7) A method for manufacturing a laminated substrate according to any one of methods 1 to 6, wherein the flow rate of the octafluorocyclobutane gas is 30 sccm or more and 100 sccm or less. [Explanation of symbols]

[0035] 20 silicon substrates 110 Silicon compound film 111 Multilayer substrate 115 Through hole 135 holes

Claims

1. It comprises a silicon substrate and a silicon compound film laminated on the silicon substrate, The aforementioned silicon compound film has through holes through which liquid passes. The silicon substrate has holes through which the liquid passes and which communicate with the through holes, The through hole is located downstream of the hole in the direction of liquid discharge. In at least a portion of the depth direction of the hole, the diameter of the hole is smaller than the diameter of the through hole on the surface in contact with the silicon substrate. A laminated substrate characterized in that the diameter of the through-holes increases monotonically as it moves away from the interface between the silicon compound film and the silicon substrate.

2. The laminated substrate according to claim 1, wherein the hole is a through-hole penetrating the silicon substrate.

3. The silicon compound film is composed of SiO, SiO ２ Si ３ N ４ SiN ｘ The laminated substrate according to claim 1, comprising one or more of SiC, SiON, SiOC, SiCN, and SiOCN.

4. The laminated substrate according to claim 1, wherein the silicon compound film is a silicon oxide film.

5. The laminated substrate according to claim 1, wherein, throughout the entire depth of the hole, the diameter of the hole is smaller than the diameter of the through hole on the surface in contact with the silicon substrate.

6. The laminated substrate according to claim 1, wherein in a portion of the hole in the depth direction, the diameter of the hole is smaller than the diameter of the through hole on the surface in contact with the silicon substrate.

7. A liquid dispensing head comprising a laminated substrate according to any one of claims 1 to 6.

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