Silicon substrate manufacturing method and liquid ejection head manufacturing method

Abstract

To provide a manufacturing method of a silicon substrate and manufacturing method of a liquid discharge head which dissolve a deposition film formed of fluorocarbon and can suppress base metal corrosion caused by a battery effect.SOLUTION: A silicon substrate includes a silicon base material, a wiring member laminated on a base material surface of the silicon base material, an electrode member containing noble metal, and a wiring formation layer having an adhesion member containing base metal between the wiring member and the electrode member. A manufacturing method of the silicon substrate includes a process of forming a deposition film from fluorocarbon gas, and a removal process of removing the deposition film formed from the fluorocarbon gas by using a removal liquid in etching the silicon substrate. The removal liquid contains a primary amine and an organic polar solvent. A water content is 10 mass% or less. A content of tetra-methyl-ammonium-hydroxide is 1 mass% or less.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a silicon substrate, and particularly to a method for manufacturing a silicon substrate used in a liquid ejection head. [Background technology]

[0002] In general MEMS (Micro Electro Mechanical Systems) processing and some semiconductor device processing, there are many examples of processing structures that penetrate silicon substrates or have a similar depth. Currently, semiconductor device microfabrication technology is being applied to processing silicon substrates used in liquid ejection heads. In general liquid ejection heads used in liquid ejection printing methods, flow path members are formed on a silicon substrate.

[0003] The flow path member comprises ejection ports for ejecting droplets and liquid flow paths connected to the ejection ports. Generally, multiple liquid flow paths are arranged in a row. Furthermore, ejection energy generating elements are provided on the silicon substrate in parts of the liquid flow paths, and droplets are ejected from the ejection ports by the energy generated by these ejection energy generating elements. Furthermore, the silicon substrate is formed with multiple liquid supply ports connected to each liquid flow path, and a common liquid chamber communicating with these liquid supply ports.

[0004] In a liquid ejection head having such a configuration, for example, the liquid is heated using thermal energy from an ejection energy generating element such as an ejection heater, and the liquid is bubbled to eject droplets from the ejection orifices. At this time, the liquid is supplied from the supply port to the liquid flow path, and the liquid is supplied from the common liquid chamber to the supply port. When forming such a supply port, an opening is required in the silicon insulating film laminated on the ejection energy generating element side, as well as in the silicon substrate. To improve density, vertical processing using dry etching may be used. Etching of silicon insulating films is generally performed using a gas primarily composed of fluorocarbons. For etching of silicon substrates, a high-speed process known as the Bosch process is preferably used. Dry etching using the Bosch process is a technique consisting of a cycle in which the following three steps are repeated in order and continuously: (1) Silicon etching with fluorine radicals (2) Formation of a fluorocarbon-based passivation layer (3) Removal of the passivation layer at the bottom of the pattern using ions

[0005] A vertical etching profile can be achieved by protecting the sidewalls of the etching pattern formed in step (1) with the passivation layer formed in step (2). As the process gas, C4F8 is usually used in step (2), and SF6 is usually used in steps (1) and (3).

[0006] A common feature of all of the above etching methods is that the deposition film formed by the fluorocarbon gas is formed in areas of the substrate that are less susceptible to impact from ions supplied from the plasma, such as the sidewalls of the etched pattern. If the deposition film is left as is, it may detach from the substrate and become foreign matter in subsequent manufacturing processes, so it must be removed. Removal methods include ashing with oxygen plasma or cleaning with a remover.

[0007] Ashing with oxygen plasma removes the deposition formed by fluorocarbon gas. This method is highly reliable as a method for removing organic films. However, its use may be limited when an organic film exists as a structure on the surface, or when oxidation of the surface is to be minimized. In such cases, cleaning the deposition film with a removal solution is effective. There are three types of removal solutions for cleaning deposition films: swelling removal, dissolution, and a combination of swelling removal and dissolution. Hydrofluoroether (HFE) is an example of a removal solution used for swelling removal. This solution has high permeability and can penetrate into the deposition film, causing it to swell and be removed from the structure. However, this solution does not have the ability to dissolve the deposition film. Therefore, the deposition film that is removed from the structure floats in the solution and may reattach to the structure, becoming a foreign substance on the structure.

[0008] On the other hand, as for the dissolving type and the combined type of swelling peeling and dissolving, as shown in Patent Document 1, Examples of such removers include those containing hydroxylamine. Hydroxylamine has a high ability to dissolve metal oxide residues (dry etching residues) through its reducing action, and therefore removers containing this component are suitable for use in semiconductor insulating film etching processes. In the semiconductor manufacturing process, resist is typically removed by ashing, followed by the deposition film and metal oxide residues generated by the ashing. However, it has been discovered that removers containing hydroxylamine can also dissolve deposition films. Although the exact reaction is not clear, it is believed that the hydroxylamine penetrates into the deposition film, swelling and peeling it off, and then dissolving the deposition film itself, and thus it is also being used for deposition film removal. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-056480 Summary of the Invention [Problem to be solved by the invention]

[0010] However, removal solutions containing hydroxylamine have the characteristic of easily corroding metal materials. Hydroxylamine itself has the ability to dissolve metal oxide residues through reduction, so there is a possibility that it will dissolve the oxide film on the metal surface. When water is added to hydroxylamine, the unshared electron pair of N reacts with H2O to form OH, as shown in the following formula (1): - This OH - However, it is thought to promote corrosion of metal materials. Furthermore, if the device being fabricated contains a laminated structure of a precious metal layer and a base metal layer, and the base metal in the base metal layer is made of a material that is corroded by the same solution, the battery effect can accelerate the erosion of the base metal. For example, consider a device as shown in Figure 1, which has a wiring formation layer 102 including a wiring member 103 on a silicon substrate 101. The wiring member 103 is connected to an electrode member 105 via a metal contact member 104 to form an electrode. If the contact member 104 is made of a base metal, TiW (titanium tungsten), and the electrode member 105 is made of a precious metal, Au, the base metal TiW is eroded, resulting in side etching. In some cases, the wiring member 103 and the electrode member 105 may even be disconnected.

[0011] [ka]

[0012] Not only hydroxylamine but also general amines can be converted to OH by adding water. - is generated (formula (2) below). An amine is a molecule in which the H atom of ammonia has been replaced by an organic substituent such as an alkyl group. A molecule with one H substitution is called a primary amine, one with two H substitutions is called a secondary amine, and one with three H substitutions is called a tertiary amine. In addition, in the case of hydroxylamine, the only substituted side chain is an OH group, not an organic group.

[0013] [ka] In formula (2), R1, R2 and R3 each independently represent a substituent.

[0014] OH generated by the reaction of amine with water - While this can improve the resist stripping ability, it can also promote metal damage. However, adjusting the water content in hydroxylamine-containing stripping solutions has not been studied to date. This is because hydroxylamine is a highly unstable material and is not available in its pure form, but is only available in the form of an aqueous solution.

[0015] Similarly, tetramethylammonium hydroxide (hereinafter referred to as TMAH) is sometimes added to improve the removal power of deposition films, but this is because the substance itself is OH. - However, when the amount of TMAH added to the remover was reduced or no TMAH was added, sufficient removal power for the deposited film could not be obtained. As described above, as long as a remover containing hydroxylamine is used, the problem of metal corrosion is unavoidable.

[0016] The present disclosure provides a method for manufacturing a silicon substrate and a method for manufacturing a liquid ejection head that can dissolve a deposition film formed by a fluorocarbon gas and suppress base metal corrosion due to the battery effect. [Means for solving the problem]

[0017] The present disclosure relates to a silicon substrate and A method for manufacturing a silicon substrate comprising: a wiring member and an electrode member containing a noble metal, which are stacked on a substrate surface of the silicon substrate; and a wiring formation layer provided with an adhesion member containing a base metal between the wiring member and the electrode member, the method comprising: Etching the silicon substrate with a fluorocarbon gas; and The silicon substrate etched by the fluorocarbon gas is Contains a primary amine and an organic polar solvent, The water content is 10% by mass or less, The content of tetramethylammonium hydroxide is 1% by mass or less A process of immersing in a removal solution is included. death, a deposition film is formed in the step of etching the silicon substrate with the fluorocarbon gas; The deposition film is dissolved in the removing solution and removed in the step of immersing the silicon substrate in the removing solution. The present invention relates to a method for manufacturing a silicon substrate. The present disclosure also provides a method for manufacturing a liquid crystal display device, comprising: a flow path member provided on the substrate, the flow path member including a discharge port for discharging a liquid and a liquid flow path communicating with the flow path and the discharge port; A method for manufacturing a liquid ejection head comprising: The present invention relates to a method for manufacturing a liquid ejection head, characterized in that the method for manufacturing the silicon substrate according to the present disclosure is used as the method for manufacturing the substrate. [Effects of the Invention]

[0018] According to the present disclosure, it is possible to provide a method for manufacturing a silicon substrate and a method for manufacturing a liquid ejection head that can dissolve a deposition film formed by a fluorocarbon gas and suppress base metal corrosion due to the battery effect. [Brief explanation of the drawings]

[0019] [Figure 1] Diagram explaining the concept of the battery effect when immersed in removal solution [Figure 2] A diagram explaining the reaction in which the resist dissolves in an organic polar solvent [Figure 3] Liquid ejection head manufacturing example DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, specific examples of embodiments for carrying out this disclosure will be described with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in these embodiments may be changed as appropriate depending on the configuration of the components to which the disclosure is applied and various conditions. In other words, it is not intended to limit the scope of this disclosure to the following embodiments.

[0021] In the present disclosure, unless otherwise specified, the expressions "XX or more and YY or less" or "XX to YY" representing a numerical range mean a numerical range including the lower and upper limits, which are the endpoints. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined in any way.

[0022] The present disclosure relates to a silicon substrate and a wiring formation layer provided with a wiring member and an electrode member containing a noble metal, which are stacked on a substrate surface of the silicon substrate, and an adhesion member containing a base metal, between the wiring member and the electrode member, the method comprising: forming a deposition film using a fluorocarbon gas in etching the silicon substrate; and a removing step of removing the deposition film formed by the fluorocarbon gas with a removing liquid; The removal solution is Contains a primary amine and an organic polar solvent, The water content is 10% by mass or less, The present invention relates to a method for producing a silicon substrate, characterized in that the content of tetramethylammonium hydroxide is 1 mass % or less. The present disclosure also provides a silicon substrate and a silicon substrate including a wiring member and an electrode member containing a noble metal laminated on a substrate surface of the silicon substrate, and a wiring formation layer provided with an adhesive member containing a base metal between the wiring member and the electrode member; a common liquid flow path provided in the silicon substrate, and a liquid supply flow path connected to the common liquid flow path; a flow path member provided on the wiring formation layer, the flow path member including a discharge port for discharging a liquid, and a liquid flow path communicating with the liquid supply flow path and the discharge port; A method for manufacturing a liquid ejection head comprising: forming a deposition film using a fluorocarbon gas in etching the silicon substrate; and a removing step of removing the deposition film formed by the fluorocarbon gas with a removing liquid; The removal solution is Contains a primary amine and an organic polar solvent, The water content is 10% by mass or less, The present invention relates to a method for manufacturing a liquid ejection head, characterized in that the content of tetramethylammonium hydroxide is 1% by mass or less.

[0023] An inkjet head will be taken as an example of application to a liquid ejection head, but the range of application of the liquid ejection head is not limited to this.

[0024] The silicon substrate manufactured by the manufacturing method of the present invention is a silicon substrate having a wiring layer provided with a wiring member and an electrode member containing a noble metal laminated on the substrate surface of a silicon base material, and an adhesion member containing a base metal between the wiring member and the electrode member. Because the electrode member and the adhesion member are electrically connected, the base metal of the adhesion member is easily corroded due to the battery effect. A known method can be suitably used to manufacture the wiring layer provided with the wiring member, electrode member, and adhesion member. Here, noble metals refer to metals with a higher standard electrode potential than hydrogen, and base metals refer to metals with a lower standard electrode potential than hydrogen. Examples of noble metals include copper, mercury, silver, palladium, platinum, gold, and iridium, while examples of base metals include lithium, potassium, calcium, aluminum, titanium, manganese, zinc, nickel, lead, titanium nitride, and TiW. Furthermore, noble metals and base metals include alloys of any metal. The noble metal used is preferably at least one selected from the group consisting of platinum, gold, and iridium. Furthermore, the base metal used is preferably at least one selected from the group consisting of aluminum, titanium, titanium nitride, and TiW.

[0025] The removal solution used in the method for manufacturing a substrate can dissolve the resist and the deposition film formed by fluorocarbon gas. There is no particular limitation on the fluorocarbon gas, as long as it is one that is commonly used in manufacturing silicon substrates. The most basic component for dissolving the deposition film is an organic polar solvent. Examples of organic polar solvents include sulfoxides such as dimethyl sulfoxide (hereinafter also referred to as DMSO); sulfones such as dimethyl sulfone, diethyl sulfone, bis(2-hydroxyethyl) sulfone, and tetramethylene sulfone; amides such as N,N-dimethylformamide, N-methylformamide, N,N-dimethylacetamide, N-methylacetamide, and N,N-diethylacetamide; N-methyl-2-pyrrolidone (hereinafter also referred to as NMP), N-ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone, N-hydroxymethyl-2-pyrrolidone, and N-hydroxymethyl-2-pyrrolidone. Examples of suitable solvents include at least one selected from the group consisting of lactams such as ethyl-2-pyrrolidone, imidazolidinones such as 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, and 1,3-diisopropyl-2-imidazolidinone, propylene carbonate, nitromethane, and acetonitrile. Among these, at least one selected from the group consisting of DMSO and NMP is preferred because they have high solubility in resists and deposition films formed with fluorocarbon gases.

[0026] The organic polar solvent preferably has a relative dielectric constant of 30 or more, more preferably 40 or more. By using a remover having an organic polar solvent with a dielectric constant of 30 or more, a deposition film formed by fluorocarbon gas can be easily dissolved. There is no particular upper limit, but it can be 100 or less, or 80 or less. The relative dielectric constant can be an actually measured value or a value from a known literature. Examples of literature include manufacturer catalogs, solvent handbooks, and chemical handbooks. The content of the organic polar solvent is not particularly limited, but is preferably 20% by mass or more, more preferably 25% by mass or more, of the total weight of the remover solution, and is preferably 80% by mass or less, more preferably 75% by mass or less.

[0027] The removal solution used in the method for manufacturing a silicon substrate contains an amine as a dissolution aid that helps dissolve the resist and the deposition film in an organic solvent. An amine is a molecule in which the H atom of ammonia is substituted with an organic substituent such as an alkyl group. The amine used as a dissolution aid that helps dissolve the resist may be a primary amine, a secondary amine, or a tertiary amine, but the amine used as a dissolution aid that helps dissolve the deposition film is a primary amine. As will be described in detail later, primary amines are preferred because they cause less steric hindrance when the unshared electron pair of the N atom in the amine reacts with the deposition film, making it easier for the amine to penetrate into the deposition film.

[0028] The primary amine contained in the remover is not particularly limited, but preferably has a substituent with less steric hindrance. Specifically, it is preferably a hydroxyalkyl group having 4 or less carbon atoms or an alkyl group having 4 or less carbon atoms, and more preferably a hydroxyalkyl group having 2 or less carbon atoms or an alkyl group having 2 or less carbon atoms. There is no particular lower limit, but it is preferably a hydroxyalkyl group or alkyl group having 1 or more carbon atoms. That is, in the primary amine represented by the general formula NHR, R is preferably a hydroxyalkyl group having 1 to 4 carbon atoms or an alkyl group having 1 to 4 carbon atoms. Examples of preferred primary amines include methylamine, methanolamine, ethylamine, 1-aminoethanol, 2-aminoethanol, n-propylamine, isopropylamine, n-propanolamine, isopropanolamine, n-butylamine, isobutylamine, tert-butylamine, n-butanolamine, isobutanolamine, and tert-butanolamine.

[0029] The content of the primary amine in the entire remover solution is not particularly limited, but is preferably 20% by mass or more, more preferably 25% by mass or more, based on the entire remover solution. By adjusting the content within this range, the reaction of the primary amine with the deposition film can be promoted. Furthermore, the content is preferably 80% by mass or less, more preferably 75% by mass or less. By adjusting the content within this range, the content of the organic polar solvent can be increased, allowing for effective dissolution of the deposition film.

[0030] An image of the action of the remover is shown in Figure 2. Here, a schematic diagram is shown using resist as an example of an object that is dissolved by the remover. A solvent 203 penetrates into the resist 201 formed on the substrate 202, causing the resist to swell and dissolve. Amine is present as a dissolution aid that promotes the swelling action of the solvent and helps the resist dissolve in the organic polar solvent.

[0031] Amines have an unshared electron pair of N, which causes reactivity with resists. For example, as shown in formula (3) below, OH groups in a positive resist can be solubilized by forming a salt with the amine. ROH (positive resist) + NR3 (amine) → RO - (Soluble)+NR3H + (3) In formula (3), R is an optional substituent.

[0032] Another example is solubilization via the nucleophilic addition of amine to carbonyl groups in the positive resist, as shown in the following formulas (4) and (5). Here, a schematic diagram using a primary amine is shown. (4) Amine undergoes a nucleophilic addition reaction with the carbonyl carbon (-C=O) in the positive resist. (5) The amine addition product is protonated, dehydrated, and deprotonated to become a soluble compound, which dissolves in the removal solution.

[0033] [ka]

[0034] On the other hand, when water is added to amine, OH - may occur, or OH may be generated by adding TMAH. - As mentioned above, this OH - The reaction between the resist and the carbonyl group in the positive resist is as shown in the following formula (6): - As a result of this reaction, the resist becomes a compound that is soluble in the removal solution, and dissolves in the removal solution.

[0035] [ka]

[0036] The action of the amine used when dissolving a resist using an organic polar solvent is as described above, and it is believed that the action of the primary amine used when dissolving a deposition film formed with a fluorocarbon gas using an organic polar solvent is similar to that described above.

[0037] The removal solution used in the method for manufacturing a silicon substrate has a water content of 10 mass % or less. When the water content is in this range, the OH in the removal solution - The generation of OH can be minimized. - Although OH has the effect of promoting the dissolution of the deposition film, from the viewpoint of battery effect, -It is preferable to suppress the generation of water. The water content is preferably less than 10% by mass, more preferably 3% by mass or less, and even more preferably 1% by mass or less. The water content is preferably 0% by mass, but may be 0.3% by mass or more, or 0.5% by mass or more. There are no particular restrictions on the type of water, and any known water can be used.

[0038] The removal solution used in the manufacturing method of silicon substrates has a TMAH content of 1 mass % or less. By having the TMAH content in this range, the OH - The generation of OH can be minimized. - Although OH has the effect of promoting the dissolution of the deposition film, from the viewpoint of battery effect, - It is preferable to suppress the generation of TMAH. The content of TMAH is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.3% by mass or less. The content of TMAH is preferably 0% by mass, but may be 0.1% by mass or more, or 0.2% by mass or more.

[0039] The remover used in the method for manufacturing a silicon substrate may contain hydroxylamine. However, because hydroxylamine has the effect of corroding metals, it is preferable that the hydroxylamine content in the remover be low. The content is preferably 2.5% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.5% by mass or less. The hydroxylamine content is preferably 0% by mass, but may be 0.1% by mass or more, or 0.2% by mass or more.

[0040] To verify the effect on deposition films formed by fluorocarbon gas, removal solutions with various compositions were used to verify their dissolution. The deposition film used was a deposition film formed by dry etching using the Bosch process, using only the process equivalent to the formation of a passivation layer, and using octafluorocyclobutane as the source gas. The results are shown in Table 1. The composition ratio of each component is the value listed on the SDS label for each removal solution. The immersion conditions for dissolving the deposition film were 60°C and 30 minutes. The erosion rate of the deposition film dissolution was determined by measuring the amount of reduction in the film thickness of the sample after immersion and calculating "measured value (nm)" / "30 min." The evaluation criteria were determined as follows: A: 25 or more B: greater than 0 and less than 25 C: No dissolution observed Level J, which contained only an organic polar solvent, did not dissolve the deposited film. Therefore, it is considered essential to combine an organic polar solvent with an amine or TMAH, and the following facts were discovered within the scope of this verification experiment.

[0041] Fact (1) When a removal solution that did not contain hydroxylamine was used, the deposition film dissolved (Levels A to I, L to N, and Q). Fact (2) When a removal solution containing TMAH was used, the deposited film dissolved (Levels C, D, H, I, and Q). When a removal solution containing TMAH was used, even if it did not contain an amine, the deposited film dissolved (Level H). Fact (3) Even when a removal solution that did not contain TMAH was used, if the removal solution contained a primary amine, the deposited film dissolved (Levels E-G, L-N, and S). However, if the removal solution contained only secondary or higher amines, the deposited film did not dissolve (Level O) (however, the amine species in Levels A-D are unknown). Fact (4) Even when using removal solutions containing the same primary amine, some removal solutions dissolved the deposited film while others did not (dissolved: levels E to G, L to N; did not dissolve: level R). From the above facts, it was found that hydroxylamine, which was previously thought to be necessary for dissolving the deposition film, is not essential.

[0042] [Table 1]

[0043] Next, from the viewpoint of suppressing the battery effect, TiW was selected in the above test as the base metal for which corrosion should be prevented. Table 1 shows a comparison of the corrosion rates of samples in which TiW was formed as a film on a silicon substrate. The sample was immersed at 60°C for 30 minutes. This is based on the assumption that if the base metal has a low corrosion rate in the film state, then when the battery effect is expressed in the silicon substrate state, there will also be little corrosion. The erosion rate of TiW was determined by measuring the reduction in the film thickness of the sample after immersion and calculating "measured value (nm)" / "30 min." The evaluation criteria were set as follows: A: The erosion rate is 0.5 or less, and almost no erosion is observed. B: Erosion rate is greater than 0.5 and less than or equal to 5 C: Erosion rate is greater than 5 and less than 10 D: Erosion rate is greater than 10 and less than 20 E: Erosion rate is greater than 20 The removal solution containing hydroxylamine, Level S, was rated E. The following facts were revealed from this investigation.

[0044] Fact (5) When a removal solution containing TMAH was used, the erosion of TiW was significant (Levels C, D, H, I, and Q). Fact (6) When a removal solution with a high water content was used, the erosion of TiW was greater (comparison of levels E, S, and A and B).

[0045] Based on these verification results, the following items are listed as desirable constituent requirements for a remover solution: Requirement (1) The content of TMAH and water in the remover solution should be as low as possible, or should not be included at all (based on facts (5) and (6)). Requirement (2) Contains a primary amine (based on Fact (3)). This is because, based on Fact (2), it is possible to use TMAH to improve the solubility of the deposition film, but based on Fact (5), it is preferable that the remover does not contain TMAH. Requirement (3) Contains an organic polar solvent (due to fact (4)). We have now newly discovered that a remover solution that meets the above requirements can dissolve fluorocarbon deposition films and also suppress the erosion of base metals due to the battery effect.

[0046] First, the purpose of "Requirement (1) The content of TMAH and water in the removal solution should be as low as possible or should not be included at all" is to - The purpose is to minimize the sources of OH. - has the effect of promoting the dissolution of the deposition film, but from the viewpoint of battery effectiveness, OH is preferred - I want to limit the amount of this generated. Specifically, within the scope of the verification results in Table 1, the majority of removal solutions for levels C, D, H, I, and Q have a range of TMAH content in the SDS descriptions, with the minimum being 1% by mass. Furthermore, the SDS lists the upper limit of the TMAH content in removal solutions for levels C and H as 3% by mass. Therefore, it is considered best to keep the content at least 1% by mass or less, and preferably less than 0.5% by mass. Regarding water, level S is stated as less than 20% by mass, while levels B and E are stated as 10% to 20% by mass. Therefore, it is considered best to have a water content of at least 10% by mass or less, preferably 3% by mass or less. In fact, for example, level R contains 10% to 20% by mass of 2-aminoethanol, but the water content is 3% to 4% by mass, and no corrosion of TiW was observed. Instead of limiting the content of TMAH or water, the idea is to ensure the dissolving ability of the deposition film by requirements (2) and (3).

[0047] Next, the purpose of "Requirement (2) Contains a primary amine" is to allow the amine, acting as a dissolution aid, to react appropriately with the deposition film. The structures of the amines contained in each level are shown in Table 2. If two or more side chains are substituted, this will cause steric hindrance when the unshared electron pair of N reacts with the deposition film, and it is thought that the penetration of the amine into the deposition film will not progress very much. For example, level O does not contain a primary amine, and does not contain methylethanol, a secondary amine. Although Level O contains amines, it did not dissolve the deposition film. For the same reason, it is speculated that removal solutions containing tertiary amines do not dissolve the deposition film, and that primary amines with short side chains are preferable. In fact, according to the results in Table 1, the deposition film was dissolved by the short-side-chain primary amines, hydroxylamine and 2-aminoethanol. While the amine species in Levels A, B, C, and D are unknown, they are certainly not hydroxylamine or 2-aminoethanol, which are required to be labeled with an SDS. Therefore, it is likely that they are secondary or higher amines, or primary amines with long side chains. From the perspective of battery performance, it is preferable to exclude hydroxylamine from the list of amines that can be included in removal solutions. Because Levels A, B, C, and D exhibit slightly inferior deposition film solubility, 2-aminoethanol is considered the most desirable component.

[0048] [Table 2]

[0049] Next, the purpose of "Requirement (3) containing an organic polar solvent" is to dissolve the deposition film. For example, within the scope of the verification results in Table 1, levels A to G and L to N are levels that are confirmed to dissolve the deposition film among levels that do not contain TMAH or hydroxylamine. While there are also removal solutions whose components are not disclosed, for example, DMSO and NMP are preferred. These two components are representative of organic polar solvents with high polarity. However, the organic polar solvent is not limited to DMSO and NMP, and from the perspective of dielectric constant, it is preferable that the organic polar solvent has a dielectric constant of 30 or higher. Furthermore, level R, which contains 10% to 20% by mass of 2-aminoethanol but failed to dissolve the deposition film, does not contain such an organic polar solvent. From these results, it can be inferred that even if the deposition film is made soluble by a primary amine, dissolution will not be possible if the solvent's ability to dissolve the deposition film is low. Furthermore, the dielectric constants of the organic solvents whose compositions are known in Table 1 are as follows. DMSO is 46.7, NMP is 32.0, propylene glycol is 32.0, ethylene glycol-n-butyl ether is 9.4, 1-(2-methoxy-2-methylethoxy)-2-propanol is 7.7, diethylene glycol mono-n-butyl ether is 10.2, and propylene glycol monomethyl ether is 12.3.

[0050] From requirement (3), it is assumed that the role of the solvent is large and that the deposition film will not dissolve with amine alone. Therefore, it is thought that there is an appropriate range for the amine content. In levels F, G, L, M, and N, the evaluation of deposition film dissolution is "A", and the evaluation of the amount of erosion of TiW is "A". The value is "A." The total content of 2-aminoethanol at each level is 20% by mass to 80% by mass. Therefore, it is considered desirable for the amine content to be within this range. [Example]

[0051] In the following examples, examples of application to more specific devices will be shown, such as a liquid ejection head, but the present invention is not limited to this.

[0052] Example 1 As an example of the present invention, a method for manufacturing a liquid ejection head having a silicon substrate as shown in FIG. 3 will be described. A wiring layer 102 having ejection energy generating elements 106 and including the ejection energy generating elements 106 and wiring members 103 is formed on a substrate surface 101-1 of a silicon substrate 101. The wiring members 103 are formed of Al doped with Cu, and TiW is formed as an adhesion member 104 and Au is formed as an electrode member 105 to extract current from the Al wiring members. An organic structure 107 is formed on the silicon substrate in a region separate from the electrodes ( FIG. 3( a)). It is preferable that the ejection energy generating elements 106 are disposed opposite ejection ports 112, which will be described later. Furthermore, the wiring layer may be laminated directly on the silicon substrate, or a substrate layer having another function may be included between the wiring layer and the silicon substrate.

[0053] To form a liquid supply channel 111 in the silicon substrate, dry etching of silicon or a silicon-based insulating film is performed. In this example, a common liquid channel 108 was first formed on the silicon substrate surface opposite the surface having the wiring formation layer 102 by high-speed silicon etching using the Bosch process (FIG. 3(b)). When forming the common liquid channel 108, etching was performed using a novolac-based positive resist 109 as a mask, and a deposition film 110 was formed on the surface and side of the resist and the side of the etched pattern using fluorocarbon gas. The resist used as the etching mask may be any known material that dissolves in a removal solution, including, for example, acrylic resins such as polymethyl methacrylate; urethane resins such as polyurethane; phenolic resins such as novolac resins; styrene resins such as polyhydroxystyrene; and resins having an aliphatic polycyclic skeleton. Next, the altered layer on the resist surface was removed by ashing, and then a removal process was carried out using a removal solution under specified conditions (temperature 60°C, time 60 min) to remove the deposition film 110 and resist 109 (Figure 3(c)). Next, a liquid supply flow path 111 was formed from the side having the wiring formation layer 102. To form the liquid supply flow path 111, first, the silicon-based interlayer insulating film of the wiring formation layer 102 was opened by dry etching mainly using fluorocarbon gas. Subsequently, high-speed silicon etching by the Bosch process was performed to connect the opening to the common liquid flow path 108 (FIG. 3(d)). When forming the liquid supply flow path 111, etching was performed using a novolac-based positive resist 109 as a mask, and a deposition film 110 was formed by fluorocarbon gas on the surface and side of the resist and on the side of the etched pattern. Furthermore, after removing the altered layer on the resist surface by ashing, a removal process was carried out using a removal solution under specified conditions (temperature 60°C, time 60 min), and the deposition film 110 and resist 109 were removed (Figure 3(e)).

[0054] Here, the ashing conditions are not particularly limited as long as they can remove the altered layer on the resist surface. For example, a method of processing with oxygen plasma excited by microwaves may be used.

[0055] In this embodiment, as described above, the resist and the deposition film are removed using a remover. It was carried out. As described above, before immersion in the removal liquid, a part of the resist altered by dry etching may be removed by ashing. It is also possible to remove all of the resist and the deposition film by ashing, but depending on the thickness of the resist, the processing time may be extremely long. Further, when there are elements such as the organic structure 107 to be left on the surface as in this embodiment, the organic structure 107 cannot be selectively left only by ashing. In such cases, the removal step using the removal liquid of the present invention is effective. That is, according to the removal step using the removal liquid of the present invention, when the silicon substrate before the removal step has an organic structure that does not dissolve in the removal liquid on the wiring formation layer, the organic structure can be left on the wiring formation layer even after the removal step is carried out. For example, the material of the organic structure 107 in this embodiment is epoxy-based, and it has been confirmed that the same material is not removed by the removal liquid. Examples of materials of other organic structures that do not dissolve in the removal liquid include epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, alkylene oxide-modified epoxy resin, glycidylamine type epoxy resin, etc. In this example, the step of removing the altered layer on the resist surface by ashing and then removing the remaining resist and deposition film with the removal liquid was selected. In this embodiment, the silicon substrate has an organic structure that does not dissolve in the removal liquid on the wiring formation layer, but the organic structure may be laminated on the silicon substrate surface where the wiring formation layer does not exist, or may be laminated on another substrate layer laminated on the silicon substrate surface.

[0056] In this example, a removal liquid containing 70% by mass of 2-aminoethanol and 30% by mass of DMSO was used. It is one representative composition included in the range shown in level L of Table 1. When the side etching amount of TiW when using this removal liquid was measured by the following procedure, the side etching amount was 0.2 μm or less at a processing temperature of 60 °C and a processing time of 30 min.

[0057] <Measurement method of side etching amount of TiW> In this example, the amount of side etching of TiW was measured as follows. A monitor pattern was prepared in which a noble metal layer and a base metal layer were stacked on the surface of a silicon substrate, and the dimensions of the noble metal layer, which was the outermost surface, were measured before a removal step using a removal solution was carried out. After performing the removal process using a removal solution, only the precious metal layer was selectively removed, exposing the base metal layer. The dimensions of the base metal layer were then measured to determine the amount of side etching. Furthermore, the side etching amount determined by performing tests using the monitor pattern in this way matched the side etching amount determined by observing the cross section of the resulting liquid ejection head using an SEM.

[0058] The allowable side etching value for TiW is, for example, approximately 5 μm in this liquid ejection head. The side etching amount is measured after a single removal process. As mentioned above, in this embodiment, the removal process is performed twice. However, since the side etching amount after a single removal process was 2.5 μm or less, it is not expected to exceed 5 μm even after two removal processes. Therefore, it was found that the battery effect was sufficiently suppressed. Using the removal solution, removal processes were performed on silicon substrates in the states shown in Figure 3(b) and Figure 3(d). The processing conditions were 60°C and 30 minutes. It was confirmed that the photoresist and deposition film were dissolved and removed as expected (Figures 3(c) and (e)).

[0059] In this example, thereafter, ejection ports 112 for ejecting droplets and liquid flow paths 113 communicating with the liquid supply flow paths and ejection ports were formed on the silicon substrate using a flow path member 114 (FIG. 3(f)). The flow path member 114, like the organic structure 107, is made of a material that is not dissolved in the removal liquid, and may be the same material as the organic structure 107 or a different material. At this time, the organic structure 107 acts as an adhesive layer between the wiring formation layer 102 and the flow path member 114. In other words, it forms part of the liquid flow path 113. Through these steps, a liquid ejection head is manufactured. It is possible to manufacture the flow path member 114. In some cases, the flow path member 114 may be formed directly without using the organic structure 107. In this case, the deposition film can also be removed by the same removal process as described above.

[0060] (Comparative Example 1) A liquid ejection head of Comparative Example 1 was manufactured in the same manner as in Example 1, except that a hydroxylamine-containing liquid corresponding to level S was used as the removal liquid. The side etching amount of TiW was approximately 0.8 μm to 16 μm after 30 minutes of treatment.

[0061] Although the mechanism is not fully understood, TiW side etching tends to worsen with time. The minimum value when using a new solution was 0.8 μm, and the maximum value observed to date was 16 μm, which occurred after six days of use. Considering the two removal processes, the amount of TiW side etching must be kept below 2.5 μm. However, this value was exceeded within one or two days of starting to use the remover. These results demonstrate that the remover of Example 1 significantly suppresses the battery effect compared to removers containing hydroxylamine.

[0062] (Comparative Example 2) A liquid ejection head of Comparative Example 2 was manufactured in the same manner as in Example 1, except that a removal solution corresponding to level R was used as the removal solution. The amount of side etching of TiW was approximately 0.2 μm after 30 minutes of treatment, which was similar to that of Example 1.

[0063] However, when the removal process was carried out using this removal solution, a large amount of residue, which appeared to be a deposition film, adhered to the silicon substrate. This removal solution does not contain DMSO or NMP as organic polar solvents. As a result, it is believed that the deposition film could not be dissolved. [Explanation of symbols]

[0064] 101 silicon substrate, 101-1 silicon substrate surface, 102 wiring formation layer, 103 wiring member, 104 adhesion member, 105 electrode member, 106 ejection energy generating element, 107 organic structure, 108 liquid common flow path, 109 resist, 110 deposition film, 111 liquid supply flow path, 112 ejection port, 113 liquid flow path communicating with the liquid supply flow path and the ejection port, 114 flow path member, 201 resist, 202 substrate, 203 solvent

Claims

1. a silicon substrate; and A method for manufacturing a silicon substrate comprising: a wiring member and an electrode member containing a noble metal, which are stacked on a substrate surface of the silicon substrate; and a wiring formation layer provided with an adhesion member containing a base metal between the wiring member and the electrode member, the method comprising: Etching the silicon substrate with a fluorocarbon gas; and The silicon substrate etched by the fluorocarbon gas is Contains a primary amine and an organic polar solvent, The water content is 10% by mass or less, The content of tetramethylammonium hydroxide is 1% by mass or less. A step of immersing in a removal solution, a deposition film is formed in the step of etching the silicon substrate with the fluorocarbon gas; a removing solution for removing the deposition film from the silicon substrate; a removing solution for removing the deposition film from the silicon substrate;

2. A silicon substrate, and A method for manufacturing a silicon substrate comprising: a wiring member and an electrode member containing a noble metal, which are stacked on a substrate surface of the silicon substrate; and a wiring formation layer provided with an adhesion member containing a base metal between the wiring member and the electrode member, the method comprising: Etching the silicon substrate with a fluorocarbon gas; and The silicon substrate etched by the fluorocarbon gas is Contains a primary amine and an organic polar solvent, The water content is 10% by mass or less, The content of tetramethylammonium hydroxide is 1% by mass or less. A step of immersing in a removal solution, 10. A method for manufacturing a silicon substrate, wherein the noble metal is Au and the base metal is TiW.

3. A silicon substrate, and a wiring member and an electrode member containing a precious metal, which are stacked on a substrate surface of the silicon substrate; and a wiring formation layer provided with an adhesive member containing a base metal between the wiring member and the electrode member, the method comprising: Etching the silicon substrate with a fluorocarbon gas; and The silicon substrate etched with the fluorocarbon gas is Contains a primary amine and an organic polar solvent, The water content is 10% by mass or less, The content of tetramethylammonium hydroxide is 1% by mass or less. A step of immersing in a removal solution, a step of performing ashing to treat the silicon substrate with oxygen plasma after the step of etching the silicon substrate with the fluorocarbon gas and before the step of immersing the silicon substrate in the remover.

4. 4. The method for producing a silicon substrate according to claim 1, wherein the organic polar solvent has a relative dielectric constant of 30 or more.

5. 5. The method for producing a silicon substrate according to claim 1, wherein the organic polar solvent comprises at least one selected from the group consisting of dimethyl sulfoxide and N-methyl-2-pyrrolidone.

6. The method for manufacturing a silicon substrate according to any one of claims 1 to 5, wherein the content of the primary amine in the remover is 20% by mass to 80% by mass.

7. General formula NH ２ 7. The method for producing a silicon substrate according to claim 1, wherein in the primary amine represented by R, R is a hydroxyalkyl group having 1 to 4 carbon atoms or an alkyl group having 1 to 4 carbon atoms.

8. 8. The method for producing a silicon substrate according to claim 7, wherein the primary amine is 2-aminoethanol.

9. 9. The method for manufacturing a silicon substrate according to claim 1, wherein the silicon substrate has an organic structure on the wiring formation layer that is insoluble in the remover.

10. The method for manufacturing a silicon substrate according to any one of claims 1 to 9, wherein the content of the water in the remover is 3 mass % or less.

11. The method for manufacturing a silicon substrate according to any one of claims 1 to 9, wherein the content of the water in the remover is 1 mass % or less.

12. The method for manufacturing a silicon substrate according to any one of claims 1 to 11, wherein the content of the organic polar solvent in the remover is 20 mass % to 80 mass %.

13. a substrate having a channel; a flow path member provided on the substrate, the flow path member including a discharge port for discharging a liquid and a liquid flow path communicating with the flow path and the discharge port; A method for manufacturing a liquid ejection head comprising: A method for manufacturing a liquid ejection head, comprising the step of using the method for manufacturing a silicon substrate according to any one of claims 1 to 12 as the method for manufacturing the substrate.

14. A substrate having a flow path; a flow path member provided on the substrate, the flow path member including a discharge port for discharging a liquid and a liquid flow path communicating with the flow path and the discharge port; A method for manufacturing a liquid ejection head comprising: The substrate is a silicon substrate; and a wiring formation layer including a wiring member and an electrode member containing a noble metal laminated on a substrate surface of the silicon substrate, and an adhesive member containing a base metal between the wiring member and the electrode member; a silicon substrate comprising: The method for manufacturing a silicon substrate includes: Etching the silicon substrate with a fluorocarbon gas; and The silicon substrate etched with the fluorocarbon gas is Contains a primary amine and an organic polar solvent, The water content is 10% by mass or less, The content of tetramethylammonium hydroxide is 1% by mass or less. A method for manufacturing a liquid ejection head, comprising the step of immersing in a remover.

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