substrate assembly

Abstract

To provide a substrate bonded body that is able to prevent cracking and peeling of a protective film.SOLUTION: A substrate bonded body has: a first substrate; a second substrate; an organic film containing silicon and carbon and bonding the first substrate and the second substrate; and a protective film containing an inorganic element and formed over the organic film from at least a part of a surface of the first substrate and at least a part of a surface of the second substrate. When a surface on a protective film side of the organic film is measured by X-ray photoelectron spectroscopy, a region in which the ratio of carbon to silicon based on the atomic% is greater than 0.0 and less than or equal to 5.0 is present within 50 nm from the surface on the protective film side of the organic film.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a substrate assembly.

Background Art

[0002] As an example of functional devices such as MEMS (Micro Electro Mechanical System) such as pressure sensors and acceleration sensors and microfluidic devices, a liquid ejection head (also referred to as an inkjet recording head or a liquid injection head) that ejects liquid can be mentioned. In the manufacture of these devices, devices composed of a substrate assembly in which substrates are joined via an organic film (adhesive) are produced.

[0003] In the liquid ejection head, the inner wall surface of the ink flow path is easily eroded by ink, and when exposed to ink for a long time, the flow path structure may collapse. In particular, when the substrate is a silicon substrate, such damage by ink is likely to occur. Further, when the ink flow path is formed by joining substrates processed into a flow path shape via an organic film (adhesive), ink may penetrate into the interface between the substrate and the organic film, and the adhesive force between the substrates may decrease.

[0004] As a method to reduce ink-induced damage to substrates and organic films (adhesives), a method has been proposed to protect the surface of the substrate assembly with a protective film (liquid-resistant film) that is resistant to ink (Patent Document 1). Figure 1 is a diagram illustrating the surface protection method for a substrate assembly (liquid spray head) described in Patent Document 1. The liquid spray head shown in Figure 1 is provided with a flow path including a nozzle opening 21 for discharging liquid, and comprises substrates 10, 15, and 20 laminated via adhesives 210 to 212. On the inner wall surface of the flow path, at least one material selected from the group consisting of tantalum oxide, hafnium oxide, and zirconium oxide (protective film 200) formed by atomic layer deposition is continuously provided from the inner wall surface to the adhesives 210 to 212. Patent Document 1 describes that by adopting such a configuration, it is possible to suppress the erosion of the silicon substrate by the liquid, thereby suppressing liquid leakage, droplet discharge failure, and peeling of the laminated substrates. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2014-124887 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, the inventors have found that even when attempting to form a protective film from the inner wall surface of the ink channel onto the organic film (adhesive), as described in Patent Document 1, it can be difficult to form a high-quality protective film on the organic film (adhesive). This is presumed to be because temperature and pressure changes applied to the substrate assembly during the manufacturing process cause slight deformation of the organic film (adhesive), stress is applied to the protective film, and cracks occur in the protective film due to the adhesion force between the protective film and the organic film, and the rigidity of the protective film.

[0007] In particular, when a protective film containing inorganic elements, as shown in Patent Document 1, is directly formed on an organic film (adhesive), if the adhesion between the protective film and the organic film (adhesive) is weak, or if the adhesion is sufficient but the rigidity of the protective film is insufficient, or both, the force acting at the interface between the protective film and the organic film (adhesive) may cause the protective film to peel off. When the protective film peels off, ink can penetrate through the peeled area, damaging the organic film (adhesive) and leading to poor bonding between substrates. Furthermore, the peeled-off protective film can become debris floating in the flow path. This may also affect the dispensing performance. Furthermore, such problems can occur not only with the above-mentioned substrate bond, but also when forming a protective film on an organic film attached to or formed on at least a part of the substrate. That is, when forming a protective film (for example, a film that protects some functional element, wiring, etc.) on an organic film, peeling and cracking of the protective film become problems when trying to form this protective film well.

[0008] This disclosure was made in view of the above-mentioned problems. Specifically, this disclosure aims to provide a substrate bond that can suppress cracking and peeling of the protective film. [Means for solving the problem]

[0009] The substrate bonded body disclosed herein is The first circuit board, The second circuit board, An organic film containing silicon and carbon, which joins the first substrate and the second substrate, A protective film containing inorganic elements, formed on the organic film from at least a portion of the surface of the first substrate and at least a portion of the surface of the second substrate, A substrate bond having, When the protective film side surface of the organic film is measured by X-ray photoelectron spectroscopy, a region where the ratio of carbon to silicon (based on atomic percentage) is greater than 0.0 and less than or equal to 5.0 exists within 50 nm of the protective film side surface of the organic film. It is characterized by the following: [Effects of the Invention]

[0010] According to this disclosure, a substrate bonding body is provided that can suppress cracking and peeling of the protective film. [Brief explanation of the drawing]

[0011] [Figure 1] A cross-sectional view of a conventional substrate assembly. [Figure 2] (A) A plan view of the substrate assembly of the present disclosure. (B) A cross-sectional view of the plan view taken along line A-A'. [Figure 3] (A) to (H) Schematic cross-sectional views illustrating the manufacturing method of the substrate bonded body according to the present disclosure. [Figure 4] (A) to (C) Enlarged cross-sectional views showing the manufacturing method of the substrate bonded body of this disclosure. [Figure 5] XPS analysis results of an organic film that has undergone a carbon reduction process. [Figure 6] XPS analysis results of an organic film that has not undergone a carbon reduction process. [Modes for carrying out the invention]

[0012] Preferred embodiments of the present disclosure will be described below with reference to the drawings. In the following description, the substrate assembly and its manufacturing method according to the present disclosure will be described using a liquid discharge head as an example, but the present disclosure is not limited to application to a liquid discharge head. In addition, in the present disclosure, the notation "XX or more and YY or less" or "XX~YY" indicating a numerical range means a numerical range including the lower and upper limits which are the endpoints, unless otherwise specified. Furthermore, when a numerical range is described in steps, the upper and lower limits of each numerical range can be arbitrarily combined. In addition, in the following description, components having the same function may be numbered the same in the drawings and their descriptions may be omitted.

[0013] Figure 2(A) is a plan view of the substrate assembly of the present disclosure, and Figure 2(B) is a cross-sectional view taken along line A-A' of the plan view. The substrate assembly of this embodiment is The first circuit board, The second circuit board, An organic film 123 that contains silicon and carbon and bonds the first substrate and the second substrate, A protective film 125 that contains an inorganic element and is formed over the organic film 123 from at least a part of the surface of the first substrate and at least a part of the surface of the second substrate, has, When the surface of the organic film 123 on the protective film 125 side is measured by X-ray photoelectron spectroscopy, a region 124 where the ratio of carbon to silicon on an atomic % basis exceeds 0.0 and is 5.0 or less exists within 50 nm from the surface of the organic film 123 on the protective film 125 side.

[0014] Further, the liquid ejection head of the present embodiment, A first substrate, A second substrate, An organic film 123 that contains silicon and carbon and bonds the first substrate and the second substrate, A protective film 125 that contains an inorganic element and is formed over the organic film 123 from at least a part of the surface of the first substrate and at least a part of the surface of the second substrate, A substrate assembly having, and A liquid ejection head having a discharge port forming member 119 provided with a top plate 117 in which a wall 118 and a discharge port 101 are formed where the first substrate further has an energy generating element 107, When the surface of the organic film 123 on the protective film 125 side is measured by X-ray photoelectron spectroscopy, a region 124 where the ratio of carbon to silicon on an atomic % basis exceeds 0.​​​​​​​​​The protective film preferably contains an inorganic element, specifically at least one element selected from the group consisting of Ta, Ti, Zr, Nb, V, Hf, and Si, in the form of an element, oxide, nitride, or carbide. Among these, it is preferable to include an oxide of at least one element selected from the group consisting of Ta, Ti, Zr, Nb, V, Hf, and Si, and more preferably to include at least one compound selected from the group consisting of TaO, TiO, SiOC, SiC, SiCN, TaN, and TiN.

[0017] The thickness of the protective film is not particularly limited, but is preferably 10 nm to 300 nm, and more preferably 50 to 200 nm. The content of inorganic elements in the protective film is preferably 25% to 75% by mass, and more preferably 30% to 70% by mass. Furthermore, the content of the above compound in the protective film is preferably 50% to 100% by mass, and more preferably 80% to 100% by mass.

[0018] In particular, we will explain this using ALD-TiO films, which are formed using titanium tetrachloride (TiCl4) as the raw material gas and pure water as the oxidizing agent, as an example.

[0019] TiCl4 and pure water are supplied alternately, and the film is formed by repeated surface saturation adsorption of the oxidizing agent and raw material gas. In the vacuum chamber, precursor molecules and water molecules, which are the raw materials, are introduced into the substrate, and the target molecules of about one molecular layer are adsorbed onto the substrate surface. At this time, functional groups in the precursor adsorb to hydroxyl groups present on the substrate surface, and the functional groups remove hydrogen atoms from the hydroxyl groups and are eliminated as volatile molecules. Subsequently, the remaining oxygen atoms bond with inorganic elements (in this case, Ti elements) in the precursor by covalent bonds. In the exhaust process, molecules that were not adsorbed onto the substrate surface during the deposition process and remain in the chamber are exhausted.

[0020] In atomic layer deposition (DDM), strong bonds are formed through covalent bonding, resulting in the creation of protective films with high adhesion. Furthermore, because DDM utilizes saturated chemiadsorption rather than plasma excitation or ion acceleration energy, a single-phase adsorption layer is formed equally on all surfaces exposed to the source gas. As a result, the film thickness is the same in all locations where the source gas can flow, providing good adhesion of the protective film to grooves and holes with high aspect ratios.

[0021] Since a protective film is formed by the reaction of hydroxyl groups chemically adsorbed on the surface of the organic film with the source gas, the number of hydroxyl groups in the organic film greatly affects the properties and adhesion of the protective film. An organic film surface state suitable for atomic layer deposition is an active state exhibiting hydrophilicity, such as that of an oxide crystal. Hydrophilicity is preferable because it has a high affinity for water molecules, making it easier to form a monolayer of water through chemical adsorption. Conversely, if the organic film surface is hydrophobic, such as that of carbon or carbide, it has a low affinity for water molecules, making it difficult to form a monolayer of water. When the organic film contains silicon, many hydroxyl groups can be introduced into the organic film, allowing the organic film surface to be controlled to the above-mentioned hydrophilic active state.

[0022] Therefore, in order to form a dense film that adheres well to the surface of an organic film, it is important to have a carbon-free, oxidized surface. For this reason, oxidizing the organic film is a viable option. It is known that carbon sublimes easily when oxidized, such as by oxygen ashing. In order to form a protective film on an organic film, it is important that the organic film has a structure that allows for the formation of an oxide layer after reducing the carbon on the surface of the organic film using a carbon reduction process such as oxidation. For this reason, it is important that the organic film of this disclosure contains at least one selected from the group consisting of organosilicon compounds and polymers of said organosilicon compounds to which hydroxyl groups can be adsorbed. When the organic film of this disclosure contains at least one selected from the group consisting of organosilicon compounds and polymers of said organosilicon compounds, more hydroxyl groups can be introduced into the organic film, making it easier to control the organic film surface to an active state exhibiting the hydrophilic properties described above.

[0023] In this embodiment, as the organosilicon compound, a compound having a structure in which benzocyclobutene has siloxane bonds and / or polysiloxane bonds, specifically divinyltetramethylsiloxanebenzocyclobutene, was used. Samples were prepared by performing oxygen ashing (carbon reduction process) by plasma oxidation using O2 plasma on the organic film surface, and samples were prepared without the oxygen ashing process. A protective film was then deposited on both samples and verified. The protective film was an ALD-TiO film deposited using titanium tetrachloride (TiCl4) as the raw material gas and pure water as the oxidizing agent.

[0024] In oxygen ashing, oxygen ions and oxygen radicals were generated by high-frequency waves while oxygen gas was flowed through the material. While oxygen ions and oxygen radicals only cause a thin oxidation of the surface of silicon films, they cause the main component carbon in organic films to volatilize, reducing the amount of carbon in the organic film.

[0025] In this embodiment, ashing was performed for 1 minute at a stage temperature of 250°C without applying RF bias power. Subsequently, a protective film was formed using an ALD-TiO film deposited from titanium tetrachloride (TiCl4) and pure water. The deposition temperature was 300°C, and the thickness of the protective film was 130 nm.

[0026] The organic film, treated under these conditions and with a protective film formed on it, was subjected to sputtering with He gas from the surface of the protective film side, and the elements Ti, O, Si, and C were measured in the depth direction by X-ray photoelectron spectroscopy (XPS) to perform elemental analysis of the protective film and the organic film. The results are shown in Figures 5 and 6. Figure 5 shows the measurement results of a sample in which carbon was removed by oxygen ashing, and Figure 6 shows the measurement results of a sample in which oxygen ashing was not performed.

[0027] As shown in Figure 5, Ti begins to decrease around an etching integration time of 300 seconds, while carbon (C) and silicon (Si) begin to increase. In this disclosure, the measurement point where Si is detected at 1.0 atomic% or more is the interface between the protective film and the organic film, and the region within 50 nm of the interface is the surface where carbon has decreased due to oxygen ashing. Furthermore, if it is difficult to capture the state of the perfect interface from the results of this measurement, the variation in composition ratio in a region of a few nanometers at the interface between the organic film and the protective film can be confirmed from the etching rate by sputtering. In this example, the thickness of the protective film was 130 nm, and the etching integration time when Si was detected at 1.0 atomic% or more was approximately 300 seconds, so the etching rate can be calculated as 130 / 300 ≈ 0.4 nm / second.

[0028] The results obtained using this measurement method allow us to determine the optimal oxygen ashing conditions for improving adhesion by defining the amount of carbon reduction within a certain range in the organic film.

[0029] As a result, within 50 nm from the protective film surface of the oxygen-ashed organic film, a region was formed where the ratio of carbon to silicon (based on atomic percentages) (hereinafter also simply referred to as the "carbon / silicon ratio") was greater than 0.0 and less than or equal to 5.0. In the portion of the organic film beyond 50 nm from the protective film surface, the carbon / silicon ratio exceeded 5.0.

[0030] This indicates that oxygen ashing reduced the amount of carbon in at least a portion of the organic film within 50 nm of the protective film surface. Furthermore, similar XPS measurements were performed using a sample that had not undergone oxygen ashing. As shown in Figure 6, similar to Figure 5, Ti began to decrease around 300 seconds of etching integration time, while C and Si began to increase. However, the carbon / silicon ratio in the organic film within 50 nm of the protective film surface remained above 10.0.

[0031] The bonded substrates created by this process were immersed in ink and tested using a PCT test apparatus (pressure cooker test) at 121°C for 20 hours. The results showed no peeling of the protective film in the samples treated with oxygen ashing. In contrast, the protective film of the samples that were not treated with oxygen ashing peeled off at the interface between the organic film and the protective film.

[0032] These results suggest that, in an organic film used to form a protective film, creating a region within 50 nm of the surface on the protective film side where the carbon / silicon ratio is greater than 0.0 and less than or equal to 5.0 makes it possible to form a protective film that is less prone to cracking and peeling.

[0033] Furthermore, it is preferable that there is no region within 50 nm from the surface of the protective film where the carbon / silicon ratio is 10.0 or more and 30.0 or less (preferably 8.0 or more and 25.0 or less, more preferably 6.0 or more and 20.0 or less).

[0034] The carbon / silicon ratio is preferably 1.0 to 4.0, and more preferably 1.5 to 3.5. The carbon / silicon ratio can be controlled by changing the stage temperature, ashing time, and RF bias power.

[0035] carbon decrease In the above embodiment, oxygen ashing, a type of oxidation treatment, was used as the process, but it is not limited to oxidation treatment. decrease When employing oxidation treatment as a process, oxygen ashing is not limited to plasma oxidation using O2 plasma; oxygen ashing may also be performed using ozone oxidation with ozone.

[0036] carbon decreaseWhen oxygen ashing is used as a process, the stage temperature can preferably be set to 5°C to 350°C. RF bias power may or may not be applied, and if applied, the RF bias power is preferably 50W to 200W. Furthermore, the ashing time is preferably 0.5 minutes to 10 minutes.

[0037] In the above embodiment, titanium tetrachloride was used as the raw material gas, but the raw material gas is not limited to titanium tetrachloride.

[0038] Furthermore, although pure water was used as the oxidizing agent in the above embodiment, the oxidizing agent is not limited to pure water.

[0039] Furthermore, it is preferable that the protective film is formed at a temperature of 150°C to 500°C.

[0040] In the above embodiment, divinyltetramethylsiloxanebenzocyclobutene was used as the organosilicon compound capable of forming an organic film (adhesive), but the organosilicon compound is not limited to this. For example, at least one compound selected from the group consisting of divinyltetramethylsiloxanebenzocyclobutene and bis-vinylsiloxanebenzocyclobutene can be used as the organosilicon compound. The organic compound can be used as a solution, and the solvent of the solution can be, for example, 1,3,5-trimethylbenzene. The viscosity of the solution can be adjusted to 15 cps to 50 cps (for example, 35 cps).

[0041] The thickness of the organic film is not particularly limited, but is preferably 0.1 μm to 10 μm, and more preferably 1 μm to 5 μm.

[0042] The first and second substrates can be any known substrate used as a substrate for functional devices such as MEMS or microfluidic devices, without any particular limitations, but silicon substrates are preferred. The thickness of the first and second substrates is also not particularly limited, but is preferably 500 μm to 1000 μm.

[0043] (Embodiment) Figure 4 is an enlarged cross-sectional view showing an example of a method for manufacturing a substrate bond in an embodiment of this disclosure. Although Figure 4 uses a first substrate 131 and a second substrate 132 for explanation, this disclosure aims to suppress peeling and cracking of the protective film 125 on the organic film 123. That is, the effect can be achieved even without a configuration in which the first substrate 131 and the second substrate 132 are bonded, but here, as one configuration in which problems occur, the configuration in which the first substrate 131 and the second substrate 132 are bonded will be explained. In Figures 4(A) and 4(B), with the same layer configuration as in the above embodiment, a region 124 is formed on the surface of the organic film 123 exposed between the first substrate 131 and the second substrate 132 by a carbon reduction process, where the carbon / silicon ratio exceeds 0.0 and is 5.0 or less. In Figure 4(C), a protective film 125 is formed on the organic film 123 from at least a portion of the surface of the first substrate 131 and at least a portion of the surface of the second substrate 132. With this configuration, the protective film 125 formed on the organic film 123 is less likely to peel off from the surface of the organic film 123, and cracks are less likely to occur in the protective film 125, making it possible to suppress poor bonding between substrates caused by ink penetration and damage to the organic film (adhesive).

[0044] While embodiments of this disclosure have been described using substrate assemblies as an example, as stated above, embodiments of this disclosure are not limited to substrate assemblies, and may also include a structure comprising a substrate, an organic film present on the substrate containing silicon and carbon, and a protective film containing inorganic elements formed on the organic film. The substrate of the structure can be the same as the first or second substrate of the substrate assembly described above. Furthermore, the organic film of the structure may be present on the substrate, for example, by adhering to at least a portion of the substrate, or by forming the organic film on the substrate. In addition, the organic film of the structure may contain silicon and carbon, and may be a compound having a structure similar to the organic film of the substrate assembly above, in which benzocyclobutene has siloxane bonds and / or polysiloxane bonds, specifically divinyltetramethylsiloxane benzocyclobutene, bis-vinylsiloxane benzocyclobutene, etc. The compound can be a solution with 1,3,5-trimethylbenzene or the like as a solvent, similar to the organic film of the substrate assembly above, and the viscosity of the solution can be adjusted to 15 cps to 50 cps (for example, 35 cps). Furthermore, the protective film of the structure may contain inorganic elements, and may contain elements similar to those in the protective film of the substrate assembly described above. Also, the protective film of the structure may be formed on the organic film, and may be formed in the same manner as the protective film of the substrate assembly described above. [Examples]

[0045] The present disclosure will be described in detail below with reference to examples and comparative examples, but the present disclosure is not limited to the configurations embodied in these examples. In addition, the term "parts" used in the examples and comparative examples means "parts by mass" unless otherwise specified.

[0046] (Example 1) As an example of this embodiment, a bonded substrate was manufactured as shown in Figure 3. Figure 3 is a schematic cross-sectional view showing the manufacturing method of the bonded substrate. As the first substrate 131, an 8-inch silicon substrate (thickness: 730 μm) was prepared with aluminum wiring, an interlayer insulating film of silicon oxide thin film, a heater thin film pattern of tantalum nitride as an energy generating element 107, and contact pads 103 for electrical conductivity with an external control unit formed on the front surface (mirror surface) (Figure 3(A)). The surface on which the aluminum wiring, the interlayer insulating film of silicon oxide thin film, the heater thin film pattern of tantalum nitride as an energy generating element 107, and the contact pads 103 for electrical conductivity with an external control unit are formed is referred to as the "front surface of the first substrate 131", and the surface opposite the front surface of the first substrate 131 is referred to as the "back surface of the first substrate 131".

[0047] A 180 μm thick UV-curing tape was applied as a protective layer to the front surface of the first substrate, and the back surface of the first substrate was thinned to a thickness of 500 μm using a grinding machine. Afterward, the ground surface was polished using a CMP (Chemical Polishing) machine to smooth it. Polishing was performed using a slurry mainly composed of colloidal silica and a polyurethane-based polishing pad. The polished surface was then cleaned to remove the slurry using a cleaning solution consisting of a mixture of 8% by mass ammonia, 8% by mass hydrogen peroxide, and 84% by mass pure water.

[0048] Next, a groove to become the second channel 113 was formed by etching (Figure 3(B)). For etching, a Bosch process was used, which involved repeating etching with SF6 gas and deposition with C4F8 gas. Etching was stopped when the average groove depth reached 300 μm. After removing the protective tape by irradiating it with ultraviolet light, the resist and etching deposits were removed with a stripping solution mainly composed of hydroxylamine.

[0049] Next, protective tape was attached to the back surface of the first substrate 131, a resist mask was formed on the front surface using the same method as described above, and a first channel 112 consisting of multiple holes was formed by dry etching from the front surface side of the first substrate 131. After etching, the protective tape was removed, and the resist and deposits were removed with a stripping solution.

[0050] Next, a silicon substrate with a thickness of 500 μm was prepared as the second substrate 132 (Figure 3(C)). A protective film was bonded to the front surface (mirror surface) of the second substrate 132, a resist mask was formed on the back surface, and the third channel 114 was formed by the Bosch process (Figure 3(D)). )). Afterwards, the protective film was peeled off, and the resist and deposits were removed with a stripping solution.

[0051] Next, adhesive 123 was applied to the back surface of the first substrate 131. First, an 8-inch silicon substrate was prepared separately, and a 1,3,5-trimethylbenzene solution of divinyltetramethylsiloxane benzocyclobutene (viscosity = 35 cps) was spin-coated onto it to a thickness of 2 μm as adhesive 123. Then, the adhesive 123 was transferred to the back surface of the first substrate 131 by bringing the bonding surface of the first substrate 131 into contact with the applied adhesive 123.

[0052] Next, the first substrate 131 and the second substrate 132 were aligned using a bonding alignment device, and temporarily fixed by applying pressure to two points on the edges of the substrates with a clamping jig (not shown) (Figures 3(E) and 4(A)). The temporarily fixed substrates were moved into the bonding device, heated to 150°C in a vacuum, and bonded under pressure for 5 minutes, after which they were cooled and removed from the bonding device. Subsequently, the adhesive 123 was cured by heat treatment at 250°C for 1 hour in an oven in a nitrogen atmosphere.

[0053] Next, an ashing process was performed for 1 minute using an O2 plasma excited at 200W at a stage temperature of 250°C, without applying RF bias power to the lower electrode. This reduced the amount of carbon on the surface of the adhesive 123 that had protruded from the junction between the first substrate 131 and the second substrate 132, forming a region 124 where the carbon / silicon ratio was greater than 0.0 and less than or equal to 5.0 (Figure 3(F), Figure 4B).

[0054] Furthermore, a TiO film with a thickness of 130 nm was formed as a protective film 125 (Figure 3(G), Figure 4(C)).

[0055] In this example, a thermal ALD-TiO film was deposited using TiCl4 and pure water, and the film was deposited by alternately supplying TiCl4 and pure water. During this deposition cycle, vaporized TiCl4 gas was transported into the furnace with nitrogen and blown for 5 seconds, followed by thorough purging and exhaust with nitrogen. Next, vaporized pure water gas was transported into the furnace with nitrogen and blown for 5 seconds, followed by thorough purging and exhaust with nitrogen. This cycle was considered one cycle, and the same cycle was repeated approximately 2000 times to deposit a 130 nm thick titanium oxide film at a deposition temperature controlled at 300°C ± 10°C, thereby obtaining a substrate assembly 130. Regarding the film deposition method, in this example, thermal atomic layer deposition was used as the atomic layer deposition method, but plasma atomic layer deposition may also be used. Furthermore, a protective film may be formed by a method other than atomic layer deposition.

[0056] The substrate assembly 130 is a structure having channels (a second channel 113 and a third channel 114) to which a first substrate 131 and a second substrate 132 are joined. Between the first substrate 131 and the second substrate 132 is an organic film (adhesive) 123 that joins these substrates. A protective film 125 is formed on the organic film 123 from at least a portion of the surface of the first substrate 131 and at least a portion of the surface of the second substrate 132. Subsequently, an etching mask was formed by laminating a dry film resist made of a positive-type resist onto the front surface of the first substrate 131 of the substrate assembly. The protective film 125 on the contact pad 103 was removed by etching with a fluorine-based etching solution.

[0057] Next, a negative-type dry film made of epoxy resin was bonded to the front surface of the first substrate 131 and exposed to light to form the wall 118 of the discharge port forming member 119. Another dry film was then bonded on top of that and exposed to light to form the top plate 117 of the discharge port forming member 119. Then, the unexposed areas were removed by development to form the discharge port 101 and pressure chamber 102 (Figure 3(H)). After that, the discharge port forming member 119 was cured by heat treatment in an oven at 200°C for 1 hour. In this way, a liquid discharge head was manufactured.

[0058] (Example 2) As Example 2 of the embodiments, a manufacturing method is shown in which the conditions for the carbon reduction step (Figure 3(F)) are changed, using the same process as in Figure 3. Steps 3(A) to 3(E) were carried out using the same manufacturing method as in Example 1.

[0059] Next, we will describe the carbon reduction process shown in Figure 3(F). In Example 2, performing O2 plasma ashing at a low temperature can further suppress the occurrence of cracks in the organic film.

[0060] In Example 2, an RF bias power of 120W was applied at a stage temperature of 16°C, and an O2 plasma ashing treatment was performed for 5 minutes to reduce carbon from the surface of the adhesive 123 that had protruded from the joint between the first substrate 131 and the second substrate 132. As a result, a substrate bond and liquid discharge head that can suppress cracking and peeling of the protective film can be obtained, similar to Example 1.

[0061] This disclosure relates to the following configuration. (Composition 1) The first circuit board, The second circuit board, An organic film containing silicon and carbon, which joins the first substrate and the second substrate, A protective film containing inorganic elements, formed on the organic film from at least a portion of the surface of the first substrate and at least a portion of the surface of the second substrate, A substrate bond having, The organic film is a substrate bond in which a region within 50 nm in the thickness direction from the protective film side surface of the organic film includes a region in which, when the surface is measured by X-ray photoelectron spectroscopy, the ratio of carbon to silicon on an atomic percentage basis is greater than 0.0 and less than or equal to 5.0. (Configuration 2) The substrate bond according to configuration 1, wherein at least one of the first substrate and the second substrate is a silicon substrate. (Composition 3) The substrate bond according to configuration 1 or 2, wherein the organic film contains at least one selected from the group consisting of organosilicon compounds and polymers of the organosilicon compounds. (Composition 4) The substrate bond according to configuration 3, wherein the organosilicon compound contains at least one compound selected from the group consisting of divinyltetramethylsiloxanebenzocyclobutene and bis-vinylsiloxanebenzocyclobutene. (Composition 5) The substrate bond according to any one of configurations 1 to 4, wherein the protective film contains at least one element selected from the group consisting of Ta, Ti, Zr, Nb, V, Hf, and Si, in elemental form, oxide, nitride, or carbide form. (Composition 6) The substrate bond according to any one of configurations 1 to 5, wherein the protective film contains at least one compound selected from the group consisting of TaO, TiO, SiOC, SiC, SiCN, TaN, and TiN. (Composition 7) A substrate bond according to any one of configurations 1 to 6, wherein the region in which the ratio of carbon to silicon on an atomic percentage basis is greater than 0.0 and 5.0 or less includes the region in which the ratio is 1.0 to 4.0. (Composition 8) circuit board and An organic film containing silicon and carbon is present on the substrate, A protective film containing inorganic elements and formed on the organic film, A structure having, The organic film is a structure that includes a region within 50 nm in thickness from the protective film side surface of the organic film, where, when the surface is measured by X-ray photoelectron spectroscopy, the ratio of carbon to silicon on an atomic percentage basis is greater than 0.0 and less than or equal to 5.0. (Composition 9) The first circuit board, The second circuit board, An organic film containing silicon and carbon, which joins the first substrate and the second substrate, A protective film containing inorganic elements, formed on the organic film from at least a portion of the surface of the first substrate and at least a portion of the surface of the second substrate, A method for manufacturing a substrate bond having the following characteristics: The manufacturing method is A step of joining the first substrate and the second substrate via the organic film, A carbon reduction step is performed to form a region within 50 nm of the protective film surface of the organic film, in which the ratio of carbon to silicon (based on atomic percentage) is greater than 0.0 and less than or equal to 5.0 when the protective film surface of the organic film is measured by X-ray photoelectron spectroscopy. A step of forming the protective film on the organic film over the region where the first substrate and the second substrate are joined, A method for manufacturing a substrate bond having the following characteristics. (Composition 10) The method for manufacturing a substrate assembly according to configuration 9, wherein the protective film is formed by atomic layer deposition. (Composition 11) The method for manufacturing a substrate bond according to configuration 10, wherein the atomic layer deposition method is at least one atomic layer deposition method selected from the group consisting of thermal atomic layer deposition and plasma atomic layer deposition. (Composition 12) A method for manufacturing a substrate bond according to any one of the configurations 9 to 11, wherein the carbon reduction step is at least one selected from the group consisting of plasma oxidation and ozone oxidation. (Composition 13) The first circuit board, The second circuit board, An organic film containing silicon and carbon, which joins the first substrate and the second substrate, A protective film containing inorganic elements, formed on the organic film from at least a portion of the surface of the first substrate and at least a portion of the surface of the second substrate, A substrate bond having, Discharge port forming member comprising a top plate with walls and discharge ports formed therein A liquid dispensing head having, The first substrate further comprises an energy generating element, The liquid dispensing head includes an organic film that, within a region of 50 nm in thickness from the protective film side surface of the organic film, has a region where, when the surface is measured by X-ray photoelectron spectroscopy, the ratio of carbon to silicon on an atomic percentage basis is greater than 0.0 and less than or equal to 5.0. [Explanation of Symbols]

[0062] 101: Discharge port, 107: Energy generating element, 115: Flow channel, 117: Top plate, 118: Wall, 119: Discharge port forming member, 123: Organic film (adhesive), 124: Region where the carbon / silicon ratio is greater than 0.0 and less than or equal to 5.0, 125: Protective film, 130: Substrate assembly, 131: First substrate, 132: Second substrate, 134: Region where the first substrate and the second substrate are joined

Claims

1. The first circuit board, The second circuit board, An organic film containing silicon and carbon, which joins the first substrate and the second substrate, A protective film containing inorganic elements, formed on the organic film from at least a portion of the surface of the first substrate and at least a portion of the surface of the second substrate, A substrate bond having, A substrate assembly wherein the organic film itself includes a region within 50 nm in the thickness direction from the protective film side surface of the organic film, where, when the surface of the organic film is measured by depth profiling using X-ray photoelectron spectroscopy, the ratio of carbon to silicon on an atomic percentage basis is greater than 0.0 and less than or equal to 5.

0.

2. The substrate bond according to claim 1, wherein at least one of the first substrate and the second substrate is a silicon substrate.

3. The substrate bond according to claim 1 or 2, wherein the organic film contains at least one selected from the group consisting of organosilicon compounds and polymers of the organosilicon compounds.

4. The substrate bond according to claim 3, wherein the organosilicon compound contains at least one compound selected from the group consisting of divinyltetramethylsiloxanebenzocyclobutene and bis-vinylsiloxanebenzocyclobutene.

5. The substrate bond according to claim 1 or 2, wherein the protective film contains at least one element selected from the group consisting of Ta, Ti, Zr, Nb, V, Hf, and Si, in elemental form, oxide, nitride, or carbide form.

6. The substrate bond according to claim 1 or 2, wherein the protective film contains at least one compound selected from the group consisting of TaO, TiO, SiOC, SiC, SiCN, TaN, and TiN.

7. The substrate bond according to claim 1 or 2, wherein the region in which the ratio of carbon to silicon on an atomic percentage basis is greater than 0.0 and 5.0 or less includes the region in which the ratio is 1.0 to 4.

0.

8. circuit board and An organic film containing silicon and carbon is present on the substrate, A protective film containing inorganic elements and formed on the organic film, A structure having, A structure wherein the organic film itself includes a region within 50 nm in the thickness direction from the protective film side surface of the organic film, in which, when the surface of the organic film is measured by depth profiling using X-ray photoelectron spectroscopy, the atomic percentage ratio of carbon to silicon is greater than 0.0 and less than or equal to 5.

0.

9. The first circuit board, The second circuit board, An organic film containing silicon and carbon, which joins the first substrate and the second substrate, A protective film containing inorganic elements, formed on the organic film from at least a portion of the surface of the first substrate and at least a portion of the surface of the second substrate, A method for manufacturing a substrate bond having the following characteristics: The manufacturing method is A step of joining the first substrate and the second substrate via the organic film, A carbon reduction step is performed to form a region within 50 nm from the protective film side surface of the organic film itself, in which, when the surface of the organic film is measured by depth profiling using X-ray photoelectron spectroscopy, the ratio of carbon to silicon on an atomic percentage basis is greater than 0.0 and less than or equal to 5.

0. A step of forming the protective film on the organic film over the region where the first substrate and the second substrate are joined, A method for manufacturing a substrate bond having the following characteristics.

10. The method for manufacturing a substrate bond according to claim 9, wherein the protective film is formed by atomic layer deposition.

11. The method for manufacturing a substrate bond according to claim 10, wherein the atomic layer deposition method is at least one atomic layer deposition method selected from the group consisting of thermal atomic layer deposition and plasma atomic layer deposition.

12. The method for manufacturing a substrate bond according to any one of claims 9 to 11, wherein the carbon reduction step is at least one selected from the group consisting of plasma oxidation and ozone oxidation.

13. The first circuit board, The second circuit board, An organic film containing silicon and carbon, which joins the first substrate and the second substrate, A protective film containing inorganic elements, formed on the organic film from at least a portion of the surface of the first substrate and at least a portion of the surface of the second substrate, A substrate bond having, Discharge port forming member comprising a top plate with walls and discharge ports formed therein A liquid dispensing head having, The first substrate further comprises an energy generating element, A liquid dispensing head wherein the organic film itself includes a region within 50 nm in the thickness direction from the protective film side surface of the organic film, where, when the surface of the organic film is measured by depth profiling using X-ray photoelectron spectroscopy, the ratio of carbon to silicon on an atomic percentage basis is greater than 0.0 and less than or equal to 5.

0.

14. The substrate bond according to claim 1, wherein in the portion of the organic film exceeding 50 nm in thickness from the protective film side surface, the ratio of carbon to silicon on an atomic percentage basis exceeds 5.

0.

15. The substrate bond according to claim 1, wherein there is no region within 50 nm in the thickness direction from the surface of the organic film in which the ratio of carbon to silicon on an atomic percentage basis is 10.0 or more and 30.0 or less.

16. The substrate bond according to claim 1, wherein the thickness of the protective film is 50 nm or more and 200 nm or less.

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