JP7811249B2 - Stripping composition - Google Patents

Description

This disclosure relates to a stripping agent composition, a method for stripping a resin mask, and a method for manufacturing electronic components.

In recent years, personal computers and various electronic devices have become increasingly power-efficient, faster, and more compact, and the wiring on the packaging substrates and other components used in these devices has become increasingly finer with each passing year. Until now, metal masking has primarily been used to form such fine wiring and connection terminals such as pillars and bumps, but due to its limited versatility and the difficulty of adapting to increasingly fine wiring, new methods are being adopted.

One new method is to use a dry film resist as a thick resin mask instead of a metal mask. This resin mask is eventually stripped and removed, using an alkaline stripper composition (strip cleaner composition).

For example, Patent Document 1 proposes a dual-purpose cleaner capable of simultaneously cleaning solder flux and dry film resist, characterized in that the amount of benzyl alcohol added is within the range of 5 to 94 wt %, the amount of amine compound is within the range of 1 to 50 wt %, and the amount of water is within the range of 3 to 90 wt % relative to the total amount. Paragraph 0011 of the same document states that the electrical conductivity of the cleaner is preferably within the range of 1 to 250 μS/cm, and paragraph 0012 states that an emulsion state is preferable at room temperature (25°C).

Japanese Patent Application Laid-Open No. 2007-224165

When forming fine wiring on a printed circuit board or the like, the stripper composition is required to have high resin mask removability (stripping ability) in order to reduce not only the residue of the resin mask but also the residue of auxiliary agents contained in the solder or plating solution used in forming the fine wiring, pillars, and bumps.
As wiring, pillars, and bumps become finer, the spaces between them also become finer, making it difficult to remove resin masks that exist in fine gaps. Therefore, stripper compositions are required to have higher resin mask removability (stripping ability).
In recent years, substrates having various patterns have been proposed. For example, as shown in Fig. 1, in the case of a substrate having a metal layer 2 (e.g., a copper plating layer) formed on the surface of the substrate and a resin mask layer 1 present in the form of perforations in the metal layer 2 (i.e., a substrate having a structure in which the periphery (side surfaces) of the resin mask layer are surrounded by a metal layer), conventional stripper compositions (cleaning compositions) have difficulty penetrating into the interface between the resin mask and the metal layer, making it difficult to strip the resin mask.

The present disclosure therefore provides a stripping agent composition with excellent resin mask removability (peelability), a resin mask stripping method, and a method for manufacturing electronic components.

In one aspect, the present disclosure relates to a stripping agent composition that contains an alkaline agent, an organic solvent other than the alkaline agent, and water, and is an O/W emulsion.

In one aspect, the present disclosure relates to a method for stripping a resin mask, comprising the step of stripping the resin mask from a substrate having the resin mask thereon using the stripper composition of the present disclosure.

In one aspect, the present disclosure relates to a method for manufacturing electronic components, including the resin mask stripping method disclosed herein.

In one aspect, the present disclosure provides a stripper composition that has excellent resin mask removal properties (stripping properties).

FIG. 1 is a schematic diagram showing an example of the appearance of the surface of a substrate to be cleaned.

[Removal agent composition]
In one or more embodiments, the present disclosure is based on the finding that a resin mask can be efficiently removed (stripped) by using a stripper that is an O/W emulsion containing an alkali, an organic solvent, and water.

In other words, in one aspect, the present disclosure relates to a stripper composition (hereinafter also referred to as the "stripper composition of the present disclosure") that contains an alkaline agent, an organic solvent other than the alkaline agent, and water, and is an O/W emulsion.

This disclosure provides a stripper composition that has excellent resin mask removal properties (peelability).

Although the details of the mechanism of action by which the effects of the present disclosure are manifested are still unclear, it is presumed as follows.
It is generally believed that peeling of the resin mask is caused by interfacial stress due to the components of the stripping composition penetrating into the resin mask and causing the resin mask to swell.
It is believed that the alkaline agent, organic solvent, and water in the stripper composition of the present disclosure penetrate into the resin mask, promoting dissociation of the alkali-soluble resin contained in the resin mask and further causing charge repulsion, thereby facilitating the removal of the resin mask.
However, when the stripping composition is an aqueous solution in which an alkaline agent and an organic solvent are dissolved in water, the alkaline agent and the organic solvent are dispersed throughout the bulk of the cleaning composition, which is thought to make it difficult for them to efficiently adsorb to the interface of the alkali-soluble resin and penetrate into the interior.
On the other hand, the liquid state of the stripper composition of the present disclosure is an O/W (oil-in-water) emulsion using water as a dispersion medium, and therefore the organic solvent containing the alkaline agent is locally concentrated to a high level, which is thought to significantly improve the adsorption of the alkali-soluble resin to the interface and the penetration into the interior, thereby enabling efficient removal (peel-off) of the resin mask.
However, the present disclosure need not be construed as being limited to this mechanism.

In one or more embodiments, the stripper composition of the present disclosure is a stripper composition (cleaning composition) for stripping a resin mask. In the present disclosure, stripping a resin mask can include dissolving the resin mask, removing the resin mask, and cleaning the resin mask. By using the stripper composition of the present disclosure to clean a substrate having a resin mask, the resin mask can be efficiently removed. Furthermore, by using the stripper composition of the present 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.

In the present disclosure, a resin mask is a mask for protecting a surface of a material from treatments such as etching, plating, heating, etc., i.e., a mask that functions as a protective film. In one or more embodiments, the resin mask may be a resist layer after exposure and development steps, a resist layer that has been subjected to at least one of exposure and development (hereinafter also referred to as "exposed and/or developed"), or a hardened resist layer.
Resin masks are formed using resists whose physical properties, such as solubility in a developer, change when exposed to light or electron beams. Resists are broadly divided into negative and positive types based on how they react with light or electron beams. Negative resists have the property of decreasing solubility in a developer when exposed to light, and the exposed portion of a layer containing negative resist (hereinafter also referred to as a "negative resist layer") is used as a resin mask after exposure and development. Positive resists have the property of increasing solubility in a developer when exposed to light, and the exposed portion of a layer containing positive resist (hereinafter also referred to as a "positive resist layer") is removed after exposure and development, and the unexposed portion is used as a resin mask. By using a resin mask with such properties, fine connections on circuit boards, such as metal wiring, metal pillars, and solder bumps, can be formed.
In one or more embodiments, the resin material for forming the resin mask may be a film-like photosensitive resin, a resist film, or a photoresist. A general-purpose resist film may be used, and a negative resist film is preferred.

(liquid state)
The liquid state of the stripper composition of the present disclosure is an O/W (oil-in-water) emulsion, and in one or more embodiments, it is a state in which an organic solvent is emulsified (dispersed) as emulsified particles (oil phase) in water (aqueous phase, continuous phase). In one or more embodiments, an alkaline agent may be present in both water and the organic solvent. The liquid state of the stripper composition can be determined from turbidity and electrical conductivity, specifically, by the method described in the Examples. The emulsification method for changing the liquid state of the stripper composition to an O/W emulsion is not particularly limited, and in one or more embodiments, mechanical emulsification methods such as those using a stirrer, homogenizer, or spray can be used. Furthermore, the emulsification may be performed by a single-pass process or by circulation operation.

(Turbidity)
From the viewpoint of obtaining an O/W emulsion with high removability, the turbidity of the release agent composition of the present disclosure is preferably 0.5 NTU or more, more preferably 10 NTU or more, and even more preferably 100 NTU or more. The turbidity of the release agent composition is a value at 60°C and can be measured using a turbidimeter, specifically, by the method described in the examples.

(Electrical Conductivity)
From the viewpoint of obtaining an O/W emulsion with high releasability, the electrical conductivity of the stripper composition of the present disclosure is preferably 1 S/m (10,000 μS/cm) or more, more preferably 3 S/m or more, and even more preferably 5 S/m or more. From the same viewpoint, it is preferably 50 S/m or less, more preferably 25 S/m or less, and even more preferably 10 S/m or less. The electrical conductivity of the stripper composition is a value at 60°C and can be measured using a benchtop electrical conductivity meter, specifically, by the method described in the Examples. The electrical conductivity value can be adjusted by the concentration of the alkaline agent and various additives.

(Component A: alkali)
The stripper composition of the present disclosure contains an alkali (hereinafter also referred to as "Component A"). Component A may be one type or a combination of two or more types.
In one or more embodiments, from the viewpoint of improving the removability (peelability) of the resin mask and from the viewpoint of forming an O/W emulsion, Component A is preferably an alkali containing at least one selected from a quaternary ammonium hydroxide and an alkanolamine, and more preferably an alkali containing a quaternary ammonium hydroxide and an alkanolamine, or an alkali consisting of a quaternary ammonium hydroxide and an alkanolamine. From the same viewpoint, the total content of the quaternary ammonium hydroxide and the alkanolamine in Component A is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 7% by mass or more.
As the quaternary ammonium hydroxide, from the viewpoint of improving the removability of the resin mask and from the viewpoint of preparing an O/W emulsion, a quaternary ammonium hydroxide having a total carbon atom number of 10 or less is preferably used, and tetramethylammonium hydroxide is more preferably used. The quaternary ammonium hydroxide may be used alone or in combination of two or more kinds.
As the alkanolamine, from the viewpoint of improving the removability (peelability) of the resin mask and from the viewpoint of preparing an O/W emulsion, an alkanolamine having a total of 6 or less carbon atoms is preferably used, and monoethanolamine is more preferably used. One type of alkanolamine may be used, or two or more types may be used in combination.

The content of Component A in the stripper composition of the present disclosure is preferably 5% by mass or more, more preferably 10% by mass or more, from the viewpoint of improving the removability (removal property) of the resin mask and from the viewpoint of forming an O/W emulsion, and from the same viewpoint, is preferably 25% by mass or less, more preferably 20% by mass or less. More specifically, the content of Component A in the stripper composition of the present disclosure is preferably 5% by mass or more and 25% by mass or less, and more preferably 10% by mass or more and 20% by mass or less. When Component A is a combination of two or more types, the content of Component A refers to the total content thereof.
When component A contains a quaternary ammonium hydroxide, the content of the quaternary ammonium hydroxide in the stripper composition of the present disclosure is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 1.5% by mass or more, from the viewpoint of improving resin mask removability (stripping ability), and is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 7% by mass or less, from the viewpoint of improving resin mask removability (stripping ability) and waste liquid treatability. When two or more types of quaternary ammonium hydroxides are used in combination, the content of the quaternary ammonium hydroxide refers to the total content thereof.
[0032] When component A contains an alkanolamine, the content of the alkanolamine in the stripper composition of the present disclosure is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 3% by mass or more, and still more preferably 7% by mass or more, from the viewpoint of improving resin mask removability (removal ability), and is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 13% by mass or less, from the viewpoints of improving resin mask removability (removal ability), waste liquid treatability, and suppressing damage to the substrate resin and the substrate metal. When two or more types of alkanolamines are used in combination, the content of alkanolamines refers to the total content thereof.
When component A contains a quaternary ammonium hydroxide and an alkanolamine, the mass ratio of the content of the quaternary ammonium hydroxide to the content of the alkanolamine in the stripper composition of the present disclosure (quaternary ammonium hydroxide content/alkanolamine content) is preferably 0.1 or more, more preferably 0.15 or more, from the viewpoint of improving the removability (removal property) of the resin mask and from the viewpoint of forming an O/W type emulsion, and from the same viewpoints, is preferably 5 or less, more preferably 1 or less, and even more preferably 0.5 or less.

(Component B: organic solvent)
The stripper composition of the present disclosure contains an organic solvent (hereinafter also referred to as “component B”) other than the alkaline agent (component A). Component B may be one type or a combination of two or more types.
From the viewpoint of improving the removability (peelability) of the resin mask and from the viewpoint of forming an O/W emulsion, Component B preferably contains an organic solvent having a hydroxyl group, and more preferably is an organic solvent having a hydroxyl group. From the same viewpoints, the content of the organic solvent having a hydroxyl group in Component B is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more.
Examples of organic solvents having a hydroxyl group include glycol ethers and aromatic alcohols.
In one or more embodiments, the glycol ether may be a compound having a structure in which 1 to 3 moles of ethylene glycol are added to an alcohol having 1 to 8 carbon atoms, such as at least one selected from diethylene glycol monobutyl ether (BDG), ethylene glycol monobenzyl ether, ethylene glycol monopropyl ether, diethylene glycol monohexyl ether, ethylene glycol monophenyl ether, diethylene glycol diethyl ether, and triethylene glycol (TEG). One type of glycol ether may be used, or two or more types may be used in combination.
In one or more embodiments, the aromatic alcohol may be a compound having a hydroxyl group bonded to at least one substituent of a substituted aromatic ring. Examples of the substituent include an alkyl group having 1 to 3 carbon atoms. Examples of the aromatic ring include a benzene ring and a naphthalene ring. From the viewpoint of improving the removability (peelability) of the resin mask, the number of carbon atoms in the aromatic alcohol is preferably 7 or more and preferably 9 or less. Examples of the aromatic alcohol include benzyl alcohol. The aromatic alcohol may be one type or a combination of two or more types.
From the viewpoint of improving the removability (peelability) of the resin mask and from the viewpoint of forming an O/W emulsion, Component B preferably contains a glycol ether, and more preferably contains diethylene glycol monobutyl ether (BDG).

The content of component B in the stripper composition of the present disclosure is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 6% by mass or more, from the viewpoints of improving resin mask removability (removal property) and forming an O/W emulsion, and from the viewpoints of improving resin mask removability (removal property), stability, and odor suppression, it is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less. More specifically, the content of component B in the stripper composition of the present disclosure is preferably 1% by mass or more and 25% by mass or less, more preferably 3% by mass or more and 20% by mass or less, and even more preferably 6% by mass or more and 15% 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 thereof.
When component B contains a glycol ether, the content of the glycol ether in the stripper composition of the present disclosure is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, from the viewpoints of improving resin mask removability (removal ability) and preparing an O/W emulsion. From the viewpoints of improving resin mask removability (removal ability), stability, and odor suppression, the content is preferably 12% by mass or less, more preferably 10% by mass or less, and even more preferably 8% by mass or less. More specifically, the content of the glycol ether in the stripper composition of the present disclosure is preferably 0.5% by mass or more and 12% by mass or less, more preferably 1% by mass or more and 10% by mass or less, and even more preferably 3% by mass or more and 8% by mass or less. When two or more glycol ethers are used in combination, the content of the glycol ethers refers to the total content thereof.
When component B contains an aromatic alcohol, the content of the aromatic alcohol in the stripper composition of the present disclosure is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, from the viewpoints of improving resin mask removability (removal ability) and preparing an O/W emulsion. From the viewpoints of improving resin mask removability (removal ability), stability, and odor suppression, the content is preferably 12% by mass or less, more preferably 10% by mass or less, and even more preferably 8% by mass or less. More specifically, the content of the aromatic alcohol in the stripper composition of the present disclosure is preferably 0.5% by mass or more and 12% by mass or less, more preferably 1% by mass or more and 10% by mass or less, and even more preferably 3% by mass or more and 8% by mass or less. When two or more aromatic alcohols are used in combination, the content of the aromatic alcohols refers to the total content thereof.

(Component C: water)
In one or more embodiments, the stripper composition of the present disclosure may further contain water (hereinafter also referred to as “component C”). Examples of component C include ion-exchanged water, RO water, distilled water, pure water, and ultrapure water.

The content of component C in the stripper composition of the present disclosure can be the remainder excluding component A, component B, and optional components (other components described below). For example, from the viewpoints of improving resin mask removability (removal performance), stability, and forming an O/W emulsion, the content of component C in the stripper composition of the present disclosure is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. From the same viewpoints, the content is preferably 99% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less. More specifically, the content of component C in the stripper composition of the present disclosure is preferably 50% by mass or more and 99% by mass or less, more preferably 60% by mass or more and 95% by mass or less, and even more preferably 70% by mass or more and 90% by mass or less.

In this disclosure, the "content of each component of the stripper composition" refers to the content of each component at the time of use, i.e., at the time when the stripper composition begins to be used for cleaning (resin mask removal treatment). In one or more embodiments, the content of each component in the stripper composition of the present disclosure can be considered to be the blending amount of each component in the stripper composition of the present disclosure.

(Component D: Salt)
In one or more embodiments, the stripper composition of the present disclosure may further contain a salt (hereinafter also referred to as "component D") from the viewpoint of improving the removability (removal property) of the resin mask and from the viewpoint of forming an O/W emulsion. From the same viewpoint, component D is preferably an organic salt.
From the same viewpoint, the acid constituting the salt is preferably a polyvalent acid, such as 1-hydroxyethane-1,1-diphosphonic acid (HEDP) or carbonic acid.
From the same viewpoint, the base constituting the salt is preferably a quaternary ammonium hydroxide. As the quaternary ammonium hydroxide, from the same viewpoint, preferably a quaternary ammonium hydroxide having a total of 10 or less carbon atoms, more preferably tetramethylammonium hydroxide (TMAH) is used.
Examples of component D include a salt of TMAH and HEDP, and a salt of TMAH and carbonic acid.

When the stripper composition of the present disclosure contains component D, the content of component D in the stripper composition of the present disclosure is preferably 0.3 mol/L or more, more preferably 0.5 mol/L or more, and even more preferably 0.6 mol/L or more, from the viewpoint of improving resin mask removability (removal performance) and from the viewpoint of forming an O/W emulsion. From the same viewpoint, it is preferably 2 mol/L or less, more preferably 1.5 mol/L or less, and even more preferably 1 mol/L or less. More specifically, the content of component D in the stripper composition of the present disclosure is preferably 0.3 mol/L or more and 2 mol/L or less, more preferably 0.5 mol/L or more and 1.5 mol/L or less, and even more preferably 0.6 mol/L or more and 1 mol/L 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 components.

(Other ingredients)
In one or more embodiments, the release agent composition of the present disclosure may further contain other components as needed to the extent that the effects of the present disclosure are not impaired. Examples of other components include solvents other than Components A to C, surfactants, chelating agents, thickeners, dispersants, rust inhibitors, polymeric compounds, solubilizers, antioxidants, preservatives, antifoaming agents, antibacterial agents, etc.

(pH)
From the viewpoint of improving the removability (removal property) of the resin mask, the pH of the stripper composition of the present disclosure is preferably 10 or more, more preferably 11 or more, and even more preferably 12 or more, and from the viewpoint of suppressing damage to the substrate resin, it is preferably 18 or less, more preferably 17 or less, and even more preferably 16 or less. The pH of the stripper composition is a value at 25°C and can be measured using pH, specifically, by the method described in the examples.

Embodiments of the stripper composition disclosed herein may be so-called one-component types, in which all components are supplied to the market in a pre-mixed state, or so-called two-component types, in which components are mixed at the time of use.

(Method for producing the release agent composition)
In one or more embodiments, the release agent composition of the present disclosure can be produced by blending Component A, Component B, Component C, and, as necessary, the optional components described above (Component D and other components) by a known method. For example, in one or more embodiments, the release agent composition of the present disclosure can be a composition comprising at least Component A, Component B, and Component C.
Therefore, the present disclosure relates to a method for producing a stripper composition, which includes a step of blending at least component A, component B, and component C. In the present disclosure, the term "blending" includes mixing component A, component B, component C, and, if necessary, the optional components described above (component D and other components) simultaneously or in any order.
In the method for producing the release agent composition of the present disclosure, the preferred amount of each component may be the same as the preferred content of each component in the release agent composition of the present disclosure described above.

The stripper composition of the present disclosure may be in a form that is used directly for cleaning, or may be prepared as a concentrate to the extent that separation, precipitation, etc. do not occur and storage stability is not impaired. The stripper composition concentrate can be diluted at the time of use so that each component has the above-mentioned content (i.e., the content at the time of cleaning). The stripper composition concentrate 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 cleaning" for the stripper composition concentrate refers to the diluted state of the stripper composition concentrate.

[Item to be cleaned]
In one or more embodiments, the object to be cleaned is a substrate having a resin mask.
Examples of the substrate include a glass epoxy multilayer substrate, a printed circuit board, a wafer, a copper plate, and an aluminum plate.
The resin mask may be, for example, a negative resin mask or a positive resin mask, with a negative resin mask being preferred in terms of the ease with which the effects of the present disclosure are exerted. Examples of negative resin masks include negative dry film resists that have been exposed and/or developed. In the present disclosure, a negative resin mask is one formed using a negative resist, and examples of such a mask include a negative resist layer that has been exposed and/or developed. In the present disclosure, a positive resin mask is one formed using a positive resist, and examples of such a mask include a positive resist layer that has been exposed and/or developed.
The thickness of the resin mask is, for example, 5 μm to 35 μm.

In one or more embodiments, the substrate (object to be cleaned) having a resin mask may be a substrate having a metal layer and a resin mask on its surface.
In one or more embodiments, the metal layer is a copper plating layer, which can be formed by, for example, an electrolytic copper plating method.
The thickness of the metal layer is, for example, 3 μm or more and 30 μm or less.
In one or more embodiments, the metal layer is used as a metal wiring or a wiring connection portion.
In one or more embodiments, the resin mask may be a resin mask (resin mask layer) present in the form of perforations in a metal layer (see FIG. 1 ). In one or more embodiments, the resin mask has its sides surrounded by a metal layer. In one or more embodiments, the shape of the resin mask layer may be a polygonal (e.g., square, hexagonal, octagonal) columnar, cylindrical, or approximately cylindrical shape. The diameter of the resin mask layer (the diameter of the circumscribed circle in the case of a polygonal shape) may be, for example, 20 μm or more and 200 μm or less. The thickness of the resin mask layer may be, for example, 5 μm or more and 50 μm or less.
The interface ratio of the resin mask present in the form of perforations (=interface line length between the resin mask and the metal layer/area of the resin mask) may be 0.01 or more and 0.5 or 0.02 or more and 0.2 or less. Here, the interface line length between the resin mask and the metal layer is, for example, the length of the circumference when the resin mask is circular when viewed from above.
A new problem has been found in that conventional strippers have poor stripping properties when used on resin masks of such a structure on objects to be cleaned. In one or more embodiments, the stripper composition of the present disclosure can suitably remove resin masks of such a structure.
In one or more embodiments, the object to be cleaned in the present disclosure may be an object to be cleaned having at least one resin mask attached to a metal layer in the form of perforations, as described above.

In one or more other embodiments, the substrate (object to be cleaned) having the resin mask may be, for example, an electronic component having a metal layer and a resin mask on its surface, or a manufacturing intermediate thereof. Examples of the electronic component include at least one component selected from a printed circuit board, a wafer, and a metal plate such as a copper plate or an aluminum plate. The manufacturing intermediate is an intermediate product in the manufacturing process of the electronic component, and includes an intermediate product after resin mask treatment.
Specific examples of objects to be cleaned include electronic components in which wiring, connection terminals, etc. are formed on the surface of a substrate by undergoing at least one of soldering using a resin mask and plating (copper plating, aluminum plating, nickel plating, tin plating, etc.). In this disclosure, soldering refers to applying solder to the resin mask-free areas of the substrate and forming solder bumps by heating. In this disclosure, plating refers to performing at least one plating process selected from copper plating, aluminum plating, nickel plating, and tin plating on the resin mask-free areas of the substrate. The resin mask-free areas refer to areas in a resist pattern (patterned resin mask) formed by developing a resin mask laminated to a substrate, where the resin mask has been removed by the developing process.

In one or more other embodiments, the substrate (object to be cleaned) having the resin mask may include a substrate having a resin mask in a fine gap. For example, the substrate having a resin mask in a fine gap may include a substrate on which a non-cured resin mask is applied to the surface of the substrate by at least one of exposure and development, and then the non-cured resin mask is removed and a circuit pattern is formed by plating. The non-plated portion of the formed circuit pattern has a cured resin mask.
In the present disclosure, in one or more embodiments, a gap refers to the distance between circuit patterns (thin line portions) (the spacing between adjacent thin line portions), and is also called a space (S). Examples of the thickness (plating thickness) of the thin line portions include 3 μm or more and 30 μm or less. The width of the thin line portions is also called a line (L). In one or more embodiments, a resin mask in a minute gap refers to a resin mask that exists in a space with a space width (S) of 10 μm or less. Examples of the thickness of the resin mask include 5 μm or more and 35 μm or less.
An example of a resin mask present in a minute gap is a resin mask present in a space with a space width (S) of 4 to 7 μm.

[Peeling method]
In one aspect, the present disclosure relates to a method for stripping a resin mask (hereinafter also referred to as the "stripping method of the present disclosure"), which includes a step of stripping a resin mask from a substrate (object to be cleaned) having the resin mask thereon using a stripper composition of the present disclosure (hereinafter also simply referred to as the "stripping step"). Examples of the object to be cleaned in the stripping step include the above-mentioned objects to be cleaned.

The stripping method of the present disclosure includes a step of stripping a resin mask from a substrate (object to be cleaned) bearing the resin mask using the stripper composition of the present disclosure (hereinafter, also simply referred to as the "stripping step"). In one or more embodiments, the stripping step includes contacting the object to be cleaned with the stripper composition of the present disclosure. The stripping method of the present disclosure allows for efficient removal of the resin mask.

Methods for stripping a resin mask from an object to be cleaned using the stripper composition of the present disclosure, or methods for contacting the object to be cleaned with the stripper composition of the present disclosure, include, for example, a method of contacting the object by immersing it in a cleaning bath containing the stripper composition, a method of contacting the object by spraying the stripper composition (shower method), and an ultrasonic cleaning method in which ultrasonic waves are applied while the object is immersed in the stripper composition. The stripper composition of the present disclosure can be used for cleaning as is without dilution. Examples of objects to be cleaned include the objects described above. The immersion time can be, for example, from 1 minute to 60 minutes, or even from 5 minutes to 30 minutes. The spray time can be, for example, from 1 minute to 60 minutes, or even from 3 minutes to 30 minutes.

In one or more embodiments, the stripping method of the present disclosure may include a step of contacting the object to be cleaned with the stripper composition of the present disclosure, rinsing with water, and drying. Examples of the rinsing method include rinsing with running water. Examples of the drying method include air blow drying.
In one or more embodiments, the stripping method of the present disclosure can include a step of contacting the object to be cleaned with the stripper composition of the present disclosure and then rinsing with water.

In the stripping method of the present disclosure, ultrasonic waves are preferably applied when the stripper composition of the present disclosure comes into contact with the object to be cleaned, as this allows the stripper composition of the present disclosure to more easily exert its stripping and cleaning power, and the ultrasonic waves are more preferably of a relatively high frequency. From the same viewpoint, the ultrasonic irradiation conditions 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.

In the stripping method of the present disclosure, the temperature of the stripper composition of the present disclosure is preferably 40°C or higher, more preferably 50°C or higher, in order to facilitate the stripping and cleaning power of the stripper composition of the present disclosure. From the viewpoint of reducing the impact on the substrate, the temperature is preferably 70°C or lower, more preferably 60°C or lower.

[Electronic component manufacturing method]
In one aspect, the present disclosure relates to a method for producing an electronic component (hereinafter also referred to as the "method for producing an electronic component of the present disclosure"), which includes the stripping method of the present disclosure. In one or more embodiments, the method for producing an electronic component of the present disclosure is a method for producing an electronic component, which includes a step (stripping step) of stripping a resin mask from a substrate (object to be cleaned) having the resin mask thereon using the stripper composition of the present disclosure. Examples of the object to be cleaned include the above-mentioned objects to be cleaned. Examples of the stripping method in the stripping step include methods similar to the above-mentioned stripping method of the present disclosure.
According to the method for producing an electronic component of the present disclosure, the resin mask adhered to the electronic component can be effectively stripped (removed), thereby enabling the production of highly reliable electronic components. Furthermore, by using the stripper composition of the present disclosure, the resin mask adhered to the electronic component can be easily stripped, thereby shortening the stripping time (cleaning time) and improving the production efficiency of the electronic component.

[kit]
In one aspect, the kit of the present disclosure relates to a kit for producing the stripper composition of the present disclosure (hereinafter also referred to as the "kit of the present disclosure"). In one or more embodiments, the kit of the present disclosure is a kit for use in either the stripping method of the present disclosure or the method for producing an electronic component of the present disclosure. The kit of the present disclosure makes it possible to obtain a stripper composition that has excellent resin mask stripping properties.
In one or more embodiments, the kit of the present disclosure includes a kit (two-component stripper composition) that contains a first liquid and a second liquid in a mutually unmixed state, with components A, B, and C each contained in either or both of the first liquid and the second liquid, and the first liquid and the second liquid being mixed at the time of use. After the first liquid and the second liquid are mixed, they may be diluted with water (component C) as needed. The first liquid and the second liquid may each contain the above-mentioned optional components (component D, other components) as needed.

The present disclosure will be explained in detail below using examples, but the present disclosure is not limited to these examples in any way.

1. Preparation of Release Agent Compositions of Examples 1 to 3 and Comparative Examples 1 and 2 The components shown in Table 1 were blended in the amounts (% by mass or molar concentration, active ingredient) shown in Table 1, and the mixture was stirred and mixed to prepare the release agent compositions of Examples 1 to 3 and Comparative Examples 1 to 3.

The following materials were used to prepare the stripper composition:
(Component A)
TMAH: Tetramethylammonium hydroxide [Resonac Corporation, 25% aqueous solution]
MEA: Monoethanolamine [Nippon Shokubai Co., Ltd.]
Diethanolamine [Tokyo Chemical Industry]
(Component B)
BDG: Diethylene glycol monobutyl ether [Nippon Nyukazai Co., Ltd.]
Benzyl alcohol [Fujifilm Wako Pure Chemical Industries, Ltd.]
(Component C)
Water [pure water of 1 μS/cm or less produced using the Organo Corporation G-10DSTSET water purification system]
(Component D)
Salt of TMAH and HEDP [prepared by adding etidronic acid dropwise to an aqueous TMAH solution]
Salt of TMAH and carbonic acid [prepared by bubbling carbon dioxide into an aqueous TMAH solution]

2. Measurement of each parameter [pH of stripping agent composition]
The pH of the stripping composition at 25°C was measured using a pH meter (HM-30G, manufactured by Toa Denpa Kogyo Co., Ltd.), and was the value measured 15 seconds after the electrode of the pH meter was immersed in the treatment liquid that had been stirred and homogenized. The results are shown in Table 1.

[Liquid state]
The stripping composition was heated to 60° C., stirred to homogenize, and then the turbidity was measured. Whether or not it was an emulsion was determined according to the following criteria. The results are shown in Table 1.
Emulsion: turbidity of 0.5 NTU or more Solubilized: turbidity of less than 0.5 NTU Furthermore, when the turbidity was 0.5 NTU or more and the electrical conductivity of the stripping composition was 1 S/m or more, it was determined to be an O/W type emulsion.

[Turbidity]
The stripping composition is heated to 60°C, stirred to homogenize, and then the turbidity is measured using a turbidity meter ZD-2A (manufactured by Joman). The sample is placed in the turbidity meter and the reading is taken after 20 seconds. The results are shown in Table 1.

[Electrical conductivity]
The stripper composition is heated to 60°C and stirred to make it uniform, and then the conductivity is measured using a tabletop electrical conductivity meter "DS-72" (manufactured by HORIBA Co., Ltd.). An electrode is immersed in the stripper composition and the value is read 15 seconds later. The results are shown in Table 1.

3. Evaluation Using the prepared stripper compositions of Examples 1 to 3 and Comparative Examples 1 and 2, the removability (stripping ability) of resin masks was evaluated as follows.
[Test piece for evaluating peelability]
The test piece for evaluating peelability was 50 mm x 50 mm in size, and had a 15 μm-thick metal layer 2 formed by copper plating on the surface of a glass epoxy multilayer substrate having a thin copper film, and a 25 μm-thick resin mask layer 1 made of negative dry film resist in circular portions with a diameter of 100 μm present in the form of perforations in the metal layer 2, with 15 μm of the 25 μm-thick resin mask being buried in the metal layer, as shown in Figure 1. There were 3,000 perforations.
[Resin mask removability (peelability)]
3 kg of the stripping composition was added to a 5-L stainless steel beaker. The beaker was heated to 60°C, and the test pieces were sprayed for 275 seconds while circulating the composition using a box-type spray washer equipped with a one-fluid nozzle (full cone) J020 (Ikeuchi Co., Ltd.) (pressure: 0.2 MPa, spray distance: 8 cm). The test pieces were then rinsed with water for 30 seconds and dried with nitrogen. Using a digital microscope (VHX-6000, Keyence Corporation), the test pieces after the spray treatment were visually observed at 300x magnification to measure the rate of resin mask residue generation. A lower value indicates better resin mask removability (peelability). The results are shown in Table 1.

As shown in Table 1, the stripper compositions of Examples 1 to 3, which are in an O/W emulsion state, were found to have superior resin mask removability (stripping ability) compared to Comparative Example 1, which is in a solubilized state, and Comparative Example 2, which is in an emulsion state.

The present disclosure provides a stripper composition that can efficiently remove resin masks. Furthermore, use of the stripper composition of the present disclosure can improve the performance and reliability of manufactured electronic components, thereby increasing the productivity of semiconductor devices.

1. Resin mask layer (dry film resist)
2. Metal layer (metal plating layer)

Claims (6)

A stripper composition for stripping a resin mask, comprising:
The method comprises the steps of: (a) preparing a coating solution containing an alkaline agent; (b) preparing an organic solvent other than the alkaline agent; (c) preparing a coating solution containing an alkaline agent; (d) preparing an organic solvent other than the alkaline agent; (e) preparing a coating solution containing an alkaline agent; (f) preparing a coating solution containing an alkaline agent; (g) preparing a coating solution containing an alkaline agent; (h) preparing a coating solution containing an alkaline agent; (i) preparing a coating solution containing an alkaline agent; (ii) preparing a coating solution containing an alkaline
the acid constituting the salt is a polyvalent acid,
The stripping composition is an O/W emulsion. The stripper composition of claim 1 , wherein the alkaline agent comprises a quaternary ammonium hydroxide and an alkanolamine. The stripper composition of claim 2 wherein the alkanolamine is monoethanolamine. The stripping composition according to claim 1 , which has an electrical conductivity of 1 S/m or more. A method for stripping a resin mask, comprising the step of stripping the resin mask from a substrate having the resin mask thereon by using the stripping composition according to any one of claims 1 to 4 . A method for manufacturing an electronic component, comprising the method for removing a resin mask according to claim 5 .