Circuit board processing method

Abstract

In one embodiment, a substrate processing method is provided that can maintain the quality of the substrate after peeling off the resin mask, even when the processing solution is circulated and reused. [Solution] This disclosure relates in one embodiment to a method for processing a substrate, comprising the following steps 1, 2, and 3. Step 1: A process of processing a substrate having a resin mask using a processing solution containing azoles. Step 2: A process to collect the processed liquid after Step 1. Step 3: The process of using the treatment liquid recovered in Step 2 as a reused treatment liquid containing azoles for use in Step 1.

Description

[Technical Field]

[0001] This disclosure relates to a method for processing substrates. [Background technology]

[0002] In recent years, personal computers and various electronic devices have seen advancements in power consumption, processing speed, and miniaturization, leading to increasingly finer wiring on package substrates and other components. While metal mask methods have traditionally been used for forming such fine wiring and connection terminals like pillars and bumps, their limited versatility and increasing difficulty in adapting to the miniaturization of wiring have led to a shift towards other, newer methods.

[0003] One new method involves using a resin mask, also known as a dry film resist. In this method, a metal seed layer is formed on an insulating substrate by electroless plating. Subsequently, the metal seed layer is laminated with a resin mask, a pattern is formed by exposure and development processes, and copper wiring and tin bumps are formed by electroplating. The resin mask remaining on the substrate is finally peeled off and removed, using an alkaline stripping cleaner (processing solution).

[0004] For example, Patent Document 1 describes a composition for removing a photoresist used to form a copper-containing pattern after the pattern has been formed, comprising an alkaline agent containing at least one selected from alkanolamines, quaternary ammonium hydroxides, and inorganic alkalis, and a Hansen solubility parameter coordinate centered at δd=16.0, δp=8.7, and δh=15.5 with a radius of 3.60 MPa. 0.5 A composition has been proposed that includes an organic solvent within a spherical range and an azole compound. Patent Document 2 proposes a composition for removing a photoresist used to form a copper-containing pattern after the pattern has been formed, comprising an alkaline agent, an ammonium ion source, and an azole compound, wherein the alkaline agent comprises one or more selected from alkanolamines, quaternary ammonium hydroxides, and inorganic alkalis. Patent Document 3 proposes a composition for removing a photoresist used to form a copper-containing pattern after the pattern has been formed, comprising an alkaline agent and an azole compound, wherein the alkaline agent is one or more selected from alkanolamines, quaternary ammonium hydroxides, and inorganic alkalis, the azole compound is one or more selected from compounds represented by specific formulas (1) to (3), and the pH is 10 or higher. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2024 / 128209 [Patent Document 2] International Publication No. 2024 / 128210 [Patent Document 3] International Publication No. 2024 / 128211 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] When forming fine wiring on printed circuit boards and the like, high cleaning performance (resin mask peeling performance, resin mask removal performance) is required for processing substrates with resin masks in order to reduce not only the residue of the resin mask but also the residue of auxiliary agents contained in the solder and plating solutions used for forming the fine wiring and bumps. Furthermore, corrosion of copper, which is widely used in wiring and connection terminals, leads to a decrease in the quality and value of package substrates. Therefore, processing solutions (stripping cleaning agents) require high corrosion prevention capabilities (etching inhibition performance). However, when processing solutions (stripping cleaning agents) are reused, changes in factors such as the concentration of components in the processing solution and processing conditions can affect the etching inhibition performance. If the etching inhibition performance is affected, for example, if the etching inhibition performance decreases, it becomes impossible to maintain the substrate quality after resin mask removal (after processing). Reducing the impact on etching inhibition performance requires considerable costs and effort in management and operation. Therefore, processing solutions are required to have the performance to stably produce substrates with excellent quality after resin mask removal (after processing), even when reused.

[0007] Therefore, this disclosure provides a substrate processing method that can maintain the quality of the substrate after resin mask removal even when the processing solution is recycled. [Means for solving the problem]

[0008] This disclosure relates, in one embodiment, to a method for processing a substrate, including steps 1, 2, and 3 described below. Step 1: A process of processing a substrate having a resin mask using a processing solution containing azoles. Step 2: A process to collect the processed liquid after Step 1. Step 3: The process of using the treatment liquid recovered in Step 2 as a reused treatment liquid containing azoles for use in Step 1. [Effects of the Invention]

[0009] According to this disclosure, a substrate processing method is provided that can maintain the quality of the substrate after resin mask removal even when the processing solution is reused. [Modes for carrying out the invention]

[0010] This disclosure is based on the finding that by including azoles in the processing solution, the deterioration of etching suppression performance can be suppressed even when the processing solution is reused, and the quality of the substrate after resin mask removal can be maintained.

[0011] This disclosure relates, in one embodiment, to a substrate processing method (hereinafter also referred to as "the substrate processing method of this disclosure") which includes the following steps 1, 2, and 3. Step 1: A process of processing a substrate having a resin mask using a processing solution containing azoles (hereinafter also referred to as "the processing solution of the present disclosure"). Step 2: A process to collect the processed liquid after Step 1. Step 3: The process of using the treatment liquid recovered in Step 2 as a reused treatment liquid containing azoles for use in Step 1.

[0012] According to this disclosure, a substrate processing method is provided that can maintain the quality of the substrate after resin mask removal even when the processing solution is recycled. Furthermore, by using the substrate processing method of this disclosure, high-quality electronic components can be obtained with a high yield.

[0013] While the detailed mechanism of action by which the effects of this disclosure are manifested remains unclear, it is presumed to be as follows. In terms of resin mask removal, adding amines and hydroxides to the treatment solution is generally known to be an effective method. It is believed that by adding amines and hydroxides, the amines and hydroxides penetrate into the resin mask, promoting the dissociation of the alkali-soluble resin incorporated into the resin mask, and further promoting the peeling of the resin mask by causing repulsion of the charges resulting from the dissociation. Amines are also thought to have the ability to etch copper. However, in this disclosure, by using a processing solution containing azoles, a protective film is formed by the adsorption of azoles onto the copper surface, and etching of copper due to amine coordination is suppressed. As a result, the processing solution containing amines and azoles is thought to exhibit good peeling performance while suppressing copper etching (corrosion). Furthermore, the processing solution containing azoles with high adsorption properties can promote the formation of a protective film and improve etching suppression performance, and it is thought that the quality of the substrate after resin mask peeling can be maintained even if factors such as the component concentration of the processing solution and processing conditions change due to the circulation of the processing solution. However, this disclosure does not have to be interpreted as being limited to this mechanism.

[0014] In the present disclosure, a resin mask is a mask for protecting the surface of a substance from processes such as etching, plating, and heating, that is, a mask formed with a resin that functions as a protective film as a component. As the resin mask, in one or more embodiments, there may be mentioned a resist layer after exposure and development processes, a resist layer that has been subjected to at least one of exposure and development processes (hereinafter, also referred to as "exposed and / or developed"), or a cured resist layer. Also, in one or more embodiments, the resin mask is formed using a resist whose physical properties such as solubility in a developer change by light, an electron beam, or the like. Resists are broadly classified into negative types and positive types according to the reaction method with light or an electron beam. The negative resist has the property that its solubility in the developer decreases when exposed, and in a layer containing a negative resist (hereinafter, also referred to as a "negative resist layer"), the exposed portion is used as a resin mask after exposure and development processes. The positive resist has the property that its solubility in the developer increases when exposed, and in a layer containing a positive resist (hereinafter, also referred to as a "positive resist layer"), the exposed portion is removed after exposure and development processes, and the unexposed portion is used as a resin mask. By using a resin mask having such properties, fine connection portions of a circuit board such as metal wiring, metal pillars, and solder bumps can be formed. As the resin material for forming the resin mask, in one or more embodiments, there may be mentioned a film-like photosensitive resin, a resist film, or a photoresist. General-purpose resist films can be used. In one or more embodiments, the resin mask is a mask for copper or tin plating used for copper or tin plating treatment.

[0015] In one or more embodiments, the substrate processing method of the present disclosure is used for a process before seed layer etching (a resin mask peeling process before a metal seed layer removing process). The substrate processing method of this disclosure is used in one or more embodiments in the manufacturing process of electronic components (electronic substrates such as printed circuit boards and package substrates).

[0016] [Process 1: Processing Process] Step 1 in the substrate processing method of the present disclosure is, in one or more embodiments, a step (processing step) of processing a substrate having a resin mask (hereinafter also referred to as "work to be processed") using a processing solution containing azoles (processing solution of the present disclosure). In one or more embodiments, the process includes cleaning the substrate having the resin mask, peeling the resin mask off the substrate having the resin mask, and removing the resin mask from the substrate having the resin mask. In one or more embodiments, the processing step includes bringing the processing liquid of the Disclosure into contact with the object to be processed.

[0017] Methods for peeling a resin mask from an object to be treated using the processing solution of the present disclosure, or methods for bringing the processing solution of the present disclosure into contact with the object to be treated, include, for example, a method of immersing the object to be treated in a washing bath containing the processing solution, a method of spraying the processing solution onto the object to be treated (shower method), and an ultrasonic cleaning method in which ultrasonic waves are irradiated onto the object to be treated while it is immersed in the processing solution. The processing solution disclosed herein can be used directly for cleaning without dilution. Examples of materials to be processed include those described later. Step 1, in one or more embodiments, includes spraying the processing solution of the present disclosure onto a substrate (work to be processed) having a resin mask. Examples of the time (contact time or immersion time) for contacting or immersing the processing liquid of the present disclosure with the object to be processed include 1 minute or more and 10 minutes or less, and more specifically, 3 minutes or more and 6 minutes or less. When the processing liquid of the present disclosure is sprayed and brought into contact with the surface, the spray time can be, for example, 1 minute or more and 10 minutes or less, or more specifically, 3 minutes or more and 6 minutes or less.

[0018] In step 1, it is preferable to irradiate the object to be treated with ultrasound when the processing solution of the present disclosure comes into contact with the object to be treated, in order to easily exhibit the peeling and cleaning power (resin mask peeling ability, resin mask removal ability) of the processing solution of the present disclosure, and it is more preferable that the ultrasound is of a relatively high frequency. From the same viewpoint, the irradiation conditions of the ultrasound are preferably, for example, 26 to 72 kHz and 80 to 1500 W, and more preferably 36 to 72 kHz and 80 to 1500 W.

[0019] In step I, the peeling and cleaning power (resin mask peeling ability, resin mask removal ability) of the processing solution of the present disclosure is easily exhibited, so the temperature of the processing solution when used is preferably 40°C or higher, more preferably 50°C or higher, and from the viewpoint of reducing the impact on the substrate, it is preferably 70°C or lower, and more preferably 60°C or lower.

[0020] Step 1 in the substrate processing method of the present disclosure may further include, in one or more embodiments, contacting the object to be processed with the processing solution of the present disclosure and then performing post-cleaning. Examples of post-cleaning in one or more embodiments include water cleaning, acid cleaning, or alkaline cleaning, which can be appropriately selected depending on the components contained in the processing solution.

[0021] Step 1 in the substrate processing method of the present disclosure may, in one or more embodiments, further include rinsing with water and drying after contacting the object to be processed with the processing solution of the present disclosure or after post-washing. Examples of rinsing methods include running water rinsing. Examples of drying methods include air blow drying. In one or more embodiments, the substrate processing method of the present disclosure may include rinsing with water after contacting the object to be processed with the processing solution of the present disclosure or after post-washing.

[0022] [Object to be processed] In one or more embodiments, the object to be processed is a substrate having a resin mask. Examples of the substrate include printed circuit boards, wafers, copper plates, aluminum plates, and the like. The resin mask may be, for example, a negative-type resin mask or a positive-type resin mask, and a negative-type resin mask is preferred because it is easier to achieve the effects of this disclosure. An example of a negative-type resin mask is an exposed and / or developed negative-type dry film resist. In this disclosure, a negative resin mask is formed using a negative resist, and an example of this is a negative resist layer that has been exposed and / or developed. In this disclosure, a positive resin mask is formed using a positive resist, and an example of this is a positive resist layer that has been exposed and / or developed. The thickness of the resin mask can be, for example, 5 μm to 35 μm or less.

[0023] In one or more embodiments, the substrate (workpiece) having the resin mask is a substrate having a copper-containing metal layer and a resin mask on its surface. In one or more embodiments, the substrate having a copper-containing metal layer and a resin mask on its surface has undergone a process in which at least one of soldering and plating is performed using the resin mask. In one or more embodiments, the copper-containing metal layer is a copper-plated layer. The copper-plated layer can be formed, for example, by an electroless copper plating method. In one or more embodiments, the copper-containing metal layer is used as metal wiring. The thickness of the copper-containing metal layer can be, for example, 3 μm to 30 μm. Examples of the substrate include insulating plates and films.

[0024] The substrate (workpiece) having the resin mask may, in one or more embodiments, be an electronic component having a copper-containing metal portion and a resin mask on its surface, and an intermediate product of the same. Examples of electronic components include at least one component selected from printed circuit boards, wafers, copper plates, and aluminum plates. The intermediate product is an intermediate product in the manufacturing process of an electronic component, and includes an intermediate product after resin mask processing. Specific examples of objects to be processed include, for example, electronic components on which wiring, connection terminals, etc., are formed on the substrate surface by undergoing a process of at least one of soldering and plating (copper plating, aluminum plating, nickel plating, tin plating, etc.) using a resin mask. In this disclosure, soldering means creating solder in areas on the substrate where a resin mask is not present and forming solder bumps by heating. In this disclosure, plating means performing at least one type of plating process selected from copper plating, aluminum plating, nickel plating, and tin plating on areas on the substrate where a resin mask is not present. Areas where a resin mask is not present refer to the parts of a resist pattern (a resin mask in the shape of a pattern) formed by developing a resin mask laminated to a substrate, where the resin mask has been removed by the developing process. Therefore, in one embodiment, this disclosure relates to the use of the processing solution of this disclosure as a cleaning agent in the manufacture of electronic components.

[0025] In one or more embodiments, the substrate (workpiece) having the resin mask is a substrate having a resist pattern (pattern-shaped resin mask) formed by developing a resin mask laminated to the substrate, and undergoing at least one of soldering and plating processes. For example, the workpiece may be a substrate having a portion where a hardened resist layer is formed on the substrate in the presence of a resin mask, and a portion where solder bumps or a plating layer are formed in the absence of a resin mask.

[0026] The resin mask may be, for example, a negative-type resin mask or a positive-type resin mask. In this disclosure, a negative-type resin mask is formed using a negative-type resist, and an example of this is an exposed and / or developed negative-type resist layer. In this disclosure, a positive-type resin mask is formed using a positive-type resist, and an example of this is an exposed and / or developed positive-type resist layer.

[0027] [Processing solution used in step 1] In one or more embodiments, the processing liquid of the present disclosure is a processing liquid for use in processing a substrate having a resin mask, a resin mask removal cleaning agent composition for cleaning a substrate having a resin mask, or a removal agent composition for removing a resin mask from a substrate having a resin mask.

[0028] The processing solution of the present disclosure can be used in one or more embodiments to clean a substrate (workpiece) having a copper-containing metal layer and a resin mask on its surface. The processing solution of the present disclosure can be used in one or more embodiments to remove a resin mask from a substrate (workpiece) having a copper-containing metal layer and a resin mask on its surface. That is, the present disclosure relates in one embodiment to the use of the processing solution of the present disclosure for removing a resin mask from a substrate (workpiece) having a copper-containing metal layer and a resin mask on its surface. By using the processing solution of this disclosure to clean a substrate (workpiece) having a copper-containing metal layer and a resin mask on its surface, the resin mask can be removed while suppressing copper corrosion. Furthermore, by using the processing solution of this disclosure to clean electronic components such as electronic circuit boards having a resin mask, high-quality electronic components can be obtained with a high yield.

[0029] The processing solution of the present disclosure used in step 1 is, in one or more embodiments, a processing solution containing azoles, and in one or more embodiments, a processing solution further containing at least one selected from amines, hydroxides, and water as described later. In one or more embodiments, the processing solution of the present disclosure may further contain at least one selected from organic solvents and ammonium salts of organic acids. The components of the treatment solution are described in detail below.

[0030] (Component D: Azoles) The azoles contained in the processing solution of this disclosure (hereinafter referred to as "component D") may be one type or a combination of two or more types. In one or more embodiments, component D is at least one selected from azoles or their derivatives, for example, at least one selected from pyrazole, thiazole, oxazole, triazole, benzotriazole, toltriazole, dimethylbenzotriazole, tetrazole, triazine, tetrazine, pentazole, imidazole, methylimidazole, phenylimidazole, dimethylbenzimidazole, 2-mercaptobenzothiazole (MBT), benzimidazole (BI), and 5,6-dimethibenzimidazole (DMBI). Among these, from the viewpoint of improving substrate quality and suppressing copper etching, at least one selected from triazole, benzotriazole, tolyltriazole, dimethylbenzotriazole, 2-mercaptobenzothiazole (MBT), benzimidazole (BI), and 5,6-dimethibenzimidazole (DMBI) is preferred, and at least one selected from 2-mercaptobenzothiazole (MBT), benzimidazole (BI), and 5,6-dimethibenzimidazole (DMBI) is more preferred. The azoles may be one type or a combination of two or more types. In one or more embodiments, the azole (component D) is a Cu inhibitor (copper corrosion inhibitor).

[0031] In one or more embodiments, component D is preferably two or more azoles from the viewpoint of improving substrate quality and suppressing copper corrosion. From the same viewpoint, the two or more azoles are preferably a combination of two or more selected from azoles or their derivatives, more preferably consisting of compounds having two or more imidazole skeletons, even more preferably consisting of compounds having two or more benzimidazole skeletons, and even more preferably a combination of benzimidazole (BI) and 5,6-dimethibenzimidazole (DMBI).

[0032] From the viewpoint of improving substrate quality and suppressing copper corrosion, the content of component D in the processing solution of this disclosure is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, and even more preferably 0.05% by mass or more. From the same viewpoint, it is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less. More specifically, the content of component D in the processing solution of this disclosure is preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.03% by mass or more and 3% by mass or less, and even more preferably 0.05% by mass or more and 1% by mass or less. When component D is a combination of two or more types, the content of component D refers to the total content of those types.

[0033] In this disclosure, "content of each component in the processing solution" means the content of each component at the time of use (washing), that is, at the time when the processing solution is first used for washing (resin mask peeling treatment). The content of each component in the processing solution of this disclosure can be considered, in one or more embodiments, as the amount of each component blended in the processing solution of this disclosure.

[0034] (Component A: Amine) In one or more embodiments of the present disclosure, the processing solution may further contain an amine (hereinafter also referred to as "component A") from the viewpoint of improving the resin mask removal performance. In one or more embodiments, component A may be an alkanolamine (amino alcohol), for example, a compound represented by the following formula (I). Component A may be one type or a combination of two or more types. [ka]

[0035] In the above equation (I), R 1 R represents a hydrogen atom, a methyl group, an ethyl group, or an aminoethyl group. 2 R represents a hydrogen atom, a hydroxyethyl group, a hydroxypropyl group, a methyl group, or an ethyl group. 3 This represents a hydroxyethyl group or a hydroxypropyl group.

[0036] Examples of alkanolamines include at least one selected from monoethanolamine (MEA), monoisopropanolamine, N-methylmonoethanolamine, N-methylisopropanolamine, N-ethylmonoethanolamine, N-ethylisopropanolamine, diethanolamine, diisopropanolamine, N-dimethylmonoethanolamine, N-dimethylmonoisopropanolamine, N-methyldiethanolamine, N-methyldiisopropanolamine, N-diethylmonoethanolamine, N-diethylmonoisopropanolamine, N-ethyldiethanolamine, N-ethyldiisopropanolamine, N-(β-aminoethyl)ethanolamine, N-(β-aminoethyl)isopropanolamine, N-(β-aminoethyl)diethanolamine, and N-(β-aminoethyl)diisopropanolamine. Among these, from the viewpoint of improving resin mask removal performance, it is preferable that component A contains monoethanolamine (MEA).

[0037] From the viewpoint of improving resin mask removal and suppressing copper corrosion, the content of component A in the processing solution of this disclosure is preferably 1% by mass or more, more preferably 6% by mass or more, even more preferably 8% by mass or more, and even more preferably 10% by mass or more. Similarly, from the viewpoint of improving resin mask removal and suppressing copper corrosion, it is preferably 18% by mass or less, more preferably 16% by mass or less, and even more preferably 14% by mass or less. Similarly, from the viewpoint of improving resin mask removal and suppressing copper corrosion, the content of component A in the processing solution of this disclosure is preferably 1% by mass or more and 18% by mass or less, more preferably 6% by mass or more and 16% by mass or less, even more preferably 8% by mass or more and 14% by mass or less, and even more preferably 10% by mass or more and less than 14% by mass. When component A is a combination of two or more types, the content of component A refers to the total content of those types.

[0038] <Mass ratio A / D> The mass ratio A / D (content of component A / content of component D) of component A to component D in the processing solution of this disclosure is preferably 10 or more, preferably 30 or more, preferably 50 or more, and preferably 200 or less from the viewpoint of improving resin mask removal performance, and preferably 150 or less from the viewpoint of suppressing copper corrosion.

[0039] (Component B: Hydroxide) In one or more embodiments, the processing solution of the present disclosure may further contain hydroxide (hereinafter also referred to as "component B"). Component B may be at least one selected from aliphatic quaternary ammonium hydroxides and inorganic metal hydroxides. Component B may be a single component or a combination of two or more components.

[0040] <Aliphatic quaternary ammonium hydroxide> Examples of aliphatic quaternary ammonium hydroxides include quaternary ammonium hydroxides represented by the following formula (II). The aliphatic quaternary ammonium hydroxide may be a single type or a combination of two or more types. [ka]

[0041] In the above equation (II), R 4 , R 5 , R 6 and R 7 Each of these groups is independently at least one selected from a methyl group, an ethyl group, a propyl group, a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group.

[0042] Quaternary ammonium hydroxides represented by formula (II) are salts consisting of a quaternary ammonium cation and a hydroxide, and include, for example, at least one selected from tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, 2-hydroxyethyltrimethylammonium hydroxide (choline), 2-hydroxyethyltriethylammonium hydroxide, 2-hydroxyethyltripropylammonium hydroxide, 2-hydroxypropyltrimethylammonium hydroxide, 2-hydroxypropyltriethylammonium hydroxide, 2-hydroxypropyltripropylammonium hydroxide, dimethylbis(2-hydroxyethyl)ammonium hydroxide, diethylbis(2-hydroxyethyl)ammonium hydroxide, dipropylbis(2-hydroxyethyl)ammonium hydroxide, tris(2-hydroxyethyl)methylammonium hydroxide, tris(2-hydroxyethyl)ethylammonium hydroxide, tris(2-hydroxyethyl)propylammonium hydroxide, tetrakis(2-hydroxyethyl)ammonium hydroxide, and tetrakis(2-hydroxypropyl)ammonium hydroxide. Among these, from the viewpoint of improving resin mask removal performance, it is preferable that component B contains tetramethylammonium hydroxide (TMAH).

[0043] If component B contains an aliphatic quaternary ammonium hydroxide, the content of aliphatic quaternary ammonium hydroxide in the treatment solution of this disclosure is preferably 0.5% by mass or more, more preferably 1.5% by mass or more, and even more preferably 2.5% by mass or more, and from the viewpoint of improving resin mask removal and suppressing copper corrosion, preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. From the same viewpoint, the content of component B in the treatment solution of this disclosure is preferably 0.5% by mass or more and 15% by mass or less, more preferably 1.5% by mass or more and 10% by mass or less, and even more preferably 2.5% by mass or more and 5% by mass or less. If the aliphatic quaternary ammonium hydroxide is a combination of two or more types, the content of aliphatic quaternary ammonium hydroxide refers to their total content.

[0044] <Inorganic metal hydroxide> Examples of inorganic metal hydroxides include alkali metal hydroxides, and from the viewpoint of improving resin mask removal (peelability), at least one selected from sodium hydroxide, potassium hydroxide, lithium hydroxide, and calcium hydroxide is preferred, with potassium hydroxide being the most preferred among these. The inorganic metal hydroxide may be a single type or a combination of two or more types. If the processing solution of the present disclosure contains an inorganic metal hydroxide, the content of the inorganic metal hydroxide in the processing solution of the present disclosure is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, even more preferably 0.5% by mass or more, and from the viewpoint of improving resin mask removal (peelability) and suppressing copper corrosion, preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 5% by mass or less. If the inorganic metal hydroxide is a combination of two or more types, the inorganic metal hydroxide content refers to the total content of those types.

[0045] From the viewpoint of improving resin mask removal performance, component B preferably contains an aliphatic quaternary ammonium hydroxide, and more preferably contains tetramethylammonium hydroxide (TMAH). The content of aliphatic quaternary ammonium hydroxide in component B is preferably 0.5% by mass or more, more preferably 1.5% by mass or more, even more preferably 2.5% by mass or more, and even more preferably 3.5% by mass or more.

[0046] The content of component B in the processing solution of this disclosure is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, from the viewpoint of improving resin mask removal (peelability) and suppressing copper corrosion, and similarly, preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 8% by mass or less. When component B is a combination of two or more types, the content of component B refers to the total content of those types.

[0047] <Mass ratio B / D> The mass ratio B / D (content of component B / content of component D) of component B to component D in the processing solution of this disclosure is preferably 10 or more, more preferably 15 or more, from the viewpoint of improving resin mask removal and suppressing copper corrosion, and preferably 200 or less, more preferably 100 or less, from the viewpoint of suppressing copper corrosion.

[0048] (Component C: water) In one or more embodiments, the processing solution of the present disclosure may further contain water (hereinafter also referred to as "component C"). In one or more embodiments, component C may include ion-exchanged water, RO water, distilled water, pure water, ultrapure water, and the like.

[0049] In one or more embodiments, the content of component C in the processing solution of this disclosure may be the remainder after excluding component D, component A, component B, and optional components described later. Specifically, from the viewpoint of improving resin mask removal and suppressing copper corrosion, the content of component C in the processing solution of this disclosure is preferably 60% by mass or more, more preferably 65% ​​by mass or more, even more preferably 70% by mass or more, and from the viewpoint of improving resin mask removal, preferably 98% by mass or less, and even more preferably 90% by mass or less. From a similar viewpoint, the content of component C in the processing solution of this disclosure is preferably 60% by mass or more and 98% by mass or less, more preferably 65% ​​by mass or more and 98% by mass or less, and even more preferably 70% by mass or more and 90% by mass or less.

[0050] (Component E: Organic solvent) In one or more embodiments of the present disclosure, the processing solution may further contain an organic solvent (hereinafter also referred to as "component E") from the viewpoint of improving resin mask removal performance. Component E may be one type or a combination of two or more types. Component E may include, in one or more embodiments, at least one solvent selected from glycol ethers and aromatic alcohols. From a similar viewpoint, examples of glycol ethers include compounds having a structure in which ethylene glycol is added to an alcohol having 1 to 8 carbon atoms in 1 to 3 moles. Specific examples of glycol ethers include at least one selected from diethylene glycol monobutyl ether (BDG), ethylene glycol monobenzyl ether, diethylene glycol monohexyl ether, ethylene glycol monophenyl ether, and diethylene glycol diethyl ether. Examples of aromatic alcohols include compounds in which, in one or more embodiments, a hydroxyl group is bonded to at least one substituent of an aromatic ring having substituents. Examples of substituents include alkyl groups having 1 to 3 carbon atoms. Examples of aromatic rings include benzene rings and naphthalene rings. From the viewpoint of improving resin mask removal (peelability), the number of carbon atoms in the aromatic alcohol is preferably 7 or more, and preferably 9 or less. Examples of aromatic alcohols include benzyl alcohol (BA). The aromatic alcohol may be a single type or a combination of two or more types.

[0051] If the processing solution of the present disclosure contains component E, the content of component E in the processing solution of the present disclosure is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, and from the viewpoint of improving resin mask removal performance, preferably 15% by mass or less, more preferably 13% by mass or less, and even more preferably 10% by mass or less. More specifically, the content of component E in the processing solution of the present disclosure is preferably 1% by mass or more and 15% by mass or less, more preferably 2% by mass or more and 13% by mass or less, and even more preferably 3% by mass or more and 10% by mass or less. If component E is a combination of two or more types, the content of component E refers to the total content of those types.

[0052] (Component F: Ammonium salt of an organic acid) In one or more embodiments of the present disclosure, the processing solution may further contain at least one ammonium salt of an organic acid (hereinafter also referred to as "component F") from the viewpoint of improving resin mask removal performance. From a similar viewpoint, component F is preferably an ammonium salt of a carboxylic acid having 1 to 5 carbon atoms, and more preferably ammonium formate (AF). Component F may be one type or a combination of two or more types.

[0053] If the processing solution of the present disclosure contains component F, the content of component F in the processing solution of the present disclosure is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.3% by mass or more, and from the viewpoint of improving resin mask removal performance, preferably 2% by mass or less, more preferably 1.5% by mass or less, and even more preferably 1% by mass or less. More specifically, the content of component F in the processing solution of the present disclosure is preferably 0.1% by mass or more and 2% by mass or less, more preferably 0.2% by mass or more and 1.5% by mass or less, and even more preferably 0.3% by mass or more and 1% by mass or less. If component F is a combination of two or more types, the content of component F refers to the total content of those types.

[0054] (Other ingredients) The processing solution of the present disclosure may further contain other components as needed, in addition to components A to F. Examples of other components include components that can be used in ordinary cleaning agents, such as alkaline agents other than components A and B, amines other than alkanolamines, solvents other than component E, corrosion inhibitors other than component D, surfactants, chelating agents, thickeners, dispersants, rust inhibitors, polymer compounds, solubilizers, antioxidants, preservatives, defoaming agents, and antibacterial agents.

[0055] When using the treatment solution of the present disclosure, the total content of organic matter derived from component D and optional components (components A, B, E, F, and other components) is preferably 30% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less, and even more preferably 16% by mass or less, and from the viewpoint of reducing the wastewater treatment load and reducing the impact on the substrate, it is preferably 2% by mass or more, more preferably 3% by mass or more, even more preferably 4% by mass or more, and even more preferably 6% by mass or more, from the viewpoint of improving the resin mask removal performance. More specifically, when using the treatment solution of the present disclosure, the total content of organic matter derived from component D and optional components (components A, B, E, F, and other components) is preferably 2% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 25% by mass or less, even more preferably 4% by mass or more and 20% by mass or less, and even more preferably 6% by mass or more and 16% by mass or less.

[0056] [Method for producing the processing solution used in Step 1] The processing solution of the present disclosure can be manufactured in one or more embodiments by compounding component D and optionally the above-mentioned optional components (components A, B, C, E, F, and other components) in a known manner. For example, the processing solution of the present disclosure may consist of at least component D. Therefore, the present disclosure relates to a method for manufacturing a processing solution that includes a step of compounding at least component D. In the present disclosure, "compounding" includes mixing component D and optionally the above-mentioned optional components (components A, B, C, E, F, and other components) simultaneously or in any order. In the method for manufacturing the processing solution of the present disclosure, the preferred amount of each component may be the same as the preferred content of each component of the processing solution of the present disclosure as described above.

[0057] In one or more embodiments of this disclosure, the treatment solution may be prepared as a concentrate by reducing the amount of water (component C) to the extent that separation, precipitation, etc., does not impair storage stability. From the viewpoint of transportation and storage, the concentrated treatment solution is preferably a concentrate with a dilution ratio of 3 times or more, and from the viewpoint of storage stability, it is preferably a concentrate with a dilution ratio of 30 times or less. The concentrated treatment solution can be used after diluting it with water (component C) so that component D and optional components (components A, B, C, E, F, and other components) are in the above-mentioned content (i.e., the content during washing). Furthermore, the concentrated treatment solution can also be used by adding each component separately at the time of use. In this disclosure, "at the time of use" or "at the time of washing" of the concentrated treatment solution refers to the state in which the concentrated treatment solution has been diluted.

[0058] [Process 2: Recovery Process] Step 2 in the substrate processing method of this disclosure is a step of recovering the processing liquid after step 1.

[0059] [Step 3: Reuse] Step 3 in the substrate processing method of this disclosure is a step in which the processing liquid recovered in step 2 is used as a recycled processing liquid containing azoles for use in step 1. In one or more embodiments, at least a portion of the processing liquid recovered in step 2 can be used as the processing liquid (reused processing liquid) in step 1. In one or more embodiments, at least a portion of the processing liquid recovered in step 2 may be mixed with processing liquid components as needed (at least one selected from the above-mentioned components A, B, C, D, E, F, and other components) to prepare a processing liquid (reused processing liquid) for use in step 1. Step 3 may also include preparing a reused processing liquid containing azoles for use in step 1 using the processing liquid recovered in step 2. In one or more embodiments of the substrate processing method of this disclosure, the processing solution is circulated and reused by repeating steps 1 to 3.

[0060] <Recycled treatment liquid> One method for preparing the reused treatment liquid is, in one or more embodiments, to mix (replenish) the treatment liquid recovered in step 2 with treatment liquid components (at least one selected from the above-mentioned components A, B, C, D, E, F, and other components) as needed. The mixing (replenishment) conditions can be set as appropriate, for example, based on the component concentrations in the treatment liquid recovered in step 2. In one or more embodiments, the recycled treatment liquid is a mixed liquid obtained by mixing the treatment liquid recovered in step 2 with at least one selected from the above-mentioned components A, B, C, D, E, F, and other components. The components contained in the recycled treatment liquid are the same as those in the treatment liquid of this disclosure described above. The preferred content of each component in the recycled treatment liquid is the same as the preferred content of each component in the treatment liquid of the present disclosure described above.

[0061] The process includes a change in a factor affecting the etching rate in the processing solution in at least one of the steps 1, 2, and 3 described above. In one or more embodiments, the change in the factor affecting the etching rate in the processing solution may be a change in the amine concentration in the processing solution, a change in the processing temperature, or a change in the processing pressure. Changes in the amine concentration in the processing solution are, in one or more embodiments, changes in amine concentration due to the addition of amine when preparing the reused processing solution (e.g., an increase in amine concentration), or changes in amine concentration due to consumption during processing or errors in measuring equipment (e.g., an increase or decrease in amine concentration).

[0062] [Manufacturing methods for electronic components] This disclosure relates, in one embodiment, to a method for manufacturing an electronic component substrate (hereinafter also referred to as "the method for manufacturing an electronic component"), including the substrate processing method of this disclosure. In one or more embodiments, the method for manufacturing electronic components of the present disclosure includes a step of processing a substrate (workpiece) having a copper-containing metal layer and a resin mask on its surface using the substrate processing method of the present disclosure (hereinafter also referred to as the "processing step"). The processing method in the processing step is the same as the substrate processing method of the present disclosure described above. The workpiece can be the workpiece described above. In one or more embodiments, the method for manufacturing an electronic component of the present disclosure may include, prior to the processing step, a step of performing at least one of soldering and plating using a resin mask on at least one electronic component selected from a printed circuit board, a wafer, and a metal plate. In one or more embodiments, the method for manufacturing an electronic component of the present disclosure may include a step of etching a copper-containing metal layer after the processing step. The method for manufacturing electronic components described herein, by performing cleaning using the substrate processing method described herein, enables the removal of resin masks adhering to the substrate (electronic component) while suppressing copper corrosion, thereby enabling the manufacture of highly reliable electronic components. Furthermore, since the removal of resin masks adhering to the electronic component becomes easier by using the substrate processing method described herein, the cleaning time can be shortened, and the manufacturing efficiency of electronic components can be improved. [Examples]

[0063] The present disclosure will be specifically described below with reference to examples, but the present disclosure is not limited in any way by these examples.

[0064] Test 1: Effect of amine concentration changes on etching inhibition performance 1-1. Preparation of treatment solutions A and B for Examples 1-2 and Comparative Example 1 Treatment solution A for Examples 1-2 and Comparative Example 1 was prepared by blending each component shown in Table 1 in the amounts (mass %) and stirring the mixture. The following evaluations were performed on the prepared treatment solutions A of Examples 1 and 2 and Comparative Example 1. After performing the evaluation described below, the used treatment solution was collected. 1% by mass of MEA was added to the collected treatment solution, and the mixture was stirred to prepare treatment solution B for Examples 1-2 and Comparative Example 1. Here, processing solution A is assumed to be the processing solution used in step 1. Processing solution B is assumed to be the recycled processing solution used in step 3.

[0065] The following materials were used to prepare treatment solutions A and B for Examples 1-2 and Comparative Example 1. (Component D: Azoles) MBT: 2-mercaptobenzothiazole [manufactured by Tokyo Chemical Industry Co., Ltd.] BI: Benzimidazole [Manufactured by Tokyo Chemical Industry Co., Ltd.] DMBI: 5,6-Dimethylbenzimidazole [Manufactured by Tokyo Chemical Industry Co., Ltd.] (Non-component D: Non-azoles) HOPO: 2-Hydroxypyridine-N-oxide [Manufactured by Suzhou Hofan Biological Co., Ltd.] (Component A: Amine) MEA: Monoethanolamine [Manufactured by Nippon Shokubai Co., Ltd.] (Component B: Hydroxide) TMAH: Tetramethylammonium hydroxide [Manufactured by Showa Denko KK, Concentration 25 mass%] (Component C: Water) Water [Purified water of 1 μS / cm or less produced by the pure water device G-10DSTSET of Organo Corporation] (Component E: Organic solvent) BDG: Butyldiglycol [Manufactured by Nippon Emulsion Co., Ltd., Diethylene glycol monobutyl ether] BA: Benzyl alcohol [Manufactured by LANXESS] (Component F: Ammonium salt of organic acid) AF: Ammonium formate [Manufactured by Fujifilm Wako Pure Chemical Corporation] (Other components) HEDP: Ethidronic acid [Manufactured by Italmatch Japan Co., Ltd., Dequest 2010, Concentration 60 mass%]

[0066] 1-2. Evaluation of treatment liquids A and B in Examples 1-2 and Comparative Example 1 The following evaluations were performed on the prepared treatment liquids A and B in Examples 1-2 and Comparative Example 1.

[0067] [Test piece] A test piece (50 mm × 50 mm) made of a solid substrate having a copper plating layer (thickness: 3 μm) on the surface was obtained by electroless plating on an insulating substrate.

[0068] [Evaluation of etching suppression performance (copper corrosiveness), change range and change rate of etching rate due to amine concentration change] 2.5 L of each treatment liquid was prepared and heated to 60°C, and while circulating in a box-type spray washer equipped with a full cone nozzle (J020, manufactured by Ikeuchi Co., Ltd.) as a spray nozzle, copper plating was applied to the surface (area per side is 25 cm 2 , 50 cm on both sides <The test piece that has undergone the following treatment is sprayed (treatment temperature: 60°C, treatment pressure: 0.03 MPa, treatment time: 4 minutes, spray distance: 80 mm). Then, the test piece is rinsed for 30 seconds in a wash bottle filled with pure water, and finally dried with nitrogen blow. The treatment solution that circulated in the washing machine is sampled, diluted with water, and the amount of copper leached is measured by ICP analysis (Agilent Technologies, Agilent 5110 ICP-OES). The density of copper is calculated to be 8.96 g / cm³ using the following formula. 3 The Cu etching rate (μm / min) was calculated from the amount of elution. Cu etching rate (μm / min) = Amount of copper leached (weight) ÷ Density of copper ÷ Plating area ÷ Processing time Furthermore, the difference between the Cu etching rate when using treatment solution A and the Cu etching rate when using treatment solution B (the range of change in etching rate (μm / min)) and the percentage change in etching rate were calculated using the following formula, with the Cu etching rate when using treatment solution A being used as the baseline. The effect of changes in amine concentration was then evaluated according to the following evaluation criteria. The lower the values ​​for the range of change and percentage change in Cu etching rate, the smaller the effect of changes in amine concentration on the Cu etching rate (copper corrosivity). The results are shown in Table 1. Change in Cu etching rate (%) = (Cu etching rate when using treatment solution B - Cu etching rate when using treatment solution A) / (Cu etching rate when using treatment solution A) × 100% <Evaluation Criteria> A: Rate of change is less than 20% B: Rate of change is 20% or more but less than 30% C: Change rate of 30% or more

[0069] [Table 1]

[0070] As shown in Table 1, Examples 1 and 2, which used a processing solution containing azoles, showed less influence on the Cu etching rate (etching suppression performance) due to changes in amine concentration compared to Comparative Example 1, which used a processing solution that did not contain azoles and did not contain azoles. Therefore, it is considered that the quality of the substrate after resin mask removal can be maintained even when the processing solution is reused. Furthermore, the peelability of the resin masks from the treatment solutions A and B in Examples 1 and 2 and Comparative Example 1 was good in all cases (data not shown).

[0071] Test 2: Influence of changes in processing conditions (processing pressure) on etching suppression performance 2-1. Preparation of treatment solutions for Example 3 and Comparative Example 2 The treatment solutions for Example 3 and Comparative Example 2 were prepared by blending each component shown in Table 2 in the amounts (mass %) and effective content listed in Table 2, and then stirring and mixing them. The same components used for preparing the treatment solutions were the same as those used for preparing Examples 1 and 2 and Comparative Example 1 described above.

[0072] 2-2. Evaluation of the treatment solutions in Example 3 and Comparative Example 2 The following evaluations were performed on the prepared treatment solutions for Example 3 and Comparative Example 2.

[0073] [Test piece] A test piece (50 mm × 50 mm) consisting of a solid substrate with a copper plating layer (thickness: 3 μm) on its surface was obtained by electroless plating onto an insulating substrate.

[0074] [Evaluation of etching suppression performance (copper corrosion resistance), rate of change of etching rate due to changes in processing pressure] (Examples 3-1 and Comparative Example 2-1: Before change in processing pressure) Each treatment solution was prepared in 2.5 L and heated to 60°C. It was then sprayed onto copper-plated test pieces while circulating through a box-type spray cleaning machine equipped with a full-cone nozzle (J020, manufactured by Ikeuchi Co., Ltd.) (treatment temperature: 60°C, treatment pressure: 0.03 MPa, treatment time: 4 minutes, spray distance: 80 mm). The test pieces were then rinsed for 30 seconds in a wash bottle filled with pure water, and finally dried with nitrogen blow. A sample of the treatment solution circulating in the cleaning machine was taken, diluted with water, and the amount of copper leached was measured using ICP analysis (Agilent Technologies, Agilent 5110 ICP-OES). The copper density was then calculated using the following formula: 8.96 g / cm³. 3 The Cu etching rate (μm / min) was calculated from the amount of elution. After evaluation, the used treatment solution was collected. (Examples 3-2 and Comparative Examples 2-2 to 2-4: After change in processing pressure) Except for using the recovered processing solution and changing the processing conditions (processing pressure) as shown in Table 2, the same evaluation as in Example 3-1 and Comparative Example 2-2 was performed, and the Cu etching rate (μm / min) for Example 3-2 and Comparative Examples 2-2 to 2-4 was calculated. Cu etching rate (μm / min) = Amount of copper leached (weight) ÷ Density of copper ÷ Plating area ÷ Processing time Furthermore, the percentage change in etching rate was calculated using the following formula, based on the difference in etching rates before and after changes in processing conditions (processing pressure) (difference in etching rates between Example 3-2 and Example 3-1, difference in etching rates between Comparative Example 2-2 and Comparative Example 2-1, difference in etching rates between Comparative Example 2-3 and Comparative Example 2-1, and difference in etching rates between Comparative Example 2-4 and Comparative Example 2-1). A lower percentage change in Cu etching rate indicates a smaller impact of changes in processing conditions (processing pressure) on the Cu etching rate (copper corrosivity). The results are shown in Table 2. Change in Cu etching rate (%) = (Cu etching rate after change in processing conditions - Cu etching rate before change in processing conditions) / (Cu etching rate before change in processing conditions) × 100%

[0075] [Table 2]

[0076] As shown in Table 2, Example 3, which used a processing solution containing azoles, did not contain azoles, and compared to Comparative Example 2, which used a processing solution without azoles, the influence of changes in processing conditions on the Cu etching rate (etching suppression performance) was smaller. Therefore, it is considered that the quality of the substrate after resin mask removal can be maintained even when the processing solution is reused. Furthermore, the peelability of the resin masks from the processing solutions in Example 3 and Comparative Example 2 was good in both cases (data not shown). [Industrial applicability]

[0077] According to this disclosure, a substrate processing method is provided that can maintain the quality of the substrate after resin mask removal even when the processing solution is reused. Furthermore, by using the substrate processing method of this disclosure, it is possible to improve the performance and reliability of the manufactured electronic components and improve the productivity of semiconductor devices.

Claims

1. A method for processing a substrate, comprising the following steps 1, 2, and 3. Step 1: A process of processing a substrate having a resin mask using a processing solution containing azoles. Step 2: A process to collect the treated liquid after Step 1. Step 3: The process of using the treatment liquid recovered in Step 2 as a reused treatment liquid containing azoles for use in Step 1.

2. The processing method according to claim 1, comprising changing a factor that affects the etching rate of the processing solution in at least one of steps 1, 2, and 3.

3. The treatment method according to claim 2, wherein the change in factors affecting the etching rate of the treatment solution is a change in the amine concentration in the treatment solution.

4. The processing method according to claim 2, wherein the change in factors affecting the etching rate of the processing solution is a change in the processing temperature.

5. The processing method according to claim 2, wherein the change in factors affecting the etching rate of the processing solution is a change in processing pressure.

6. The treatment method according to claim 1, wherein the treatment solution contains two or more azoles.

7. The treatment method according to claim 1, wherein the treatment solution further contains an amine.

8. The treatment method according to claim 1, wherein the treatment solution further contains hydroxide.

9. The treatment method according to claim 1, wherein the treatment solution further contains water.

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