TREATMENT LIQUID AND TREATMENT LIQUID-HOUSING ARTICLE

It is an object of the invention to provide a treatment liquid that, when used as a developer or a rinsing liquid for a metal resist, exhibits a high ability to suppress the occurrence of pattern defects and a high pattern resolution and exhibits a high ability to suppress the occurrence of defects originating from the treatment liquid even after storage under cyclic heating and cooling and a high pattern resolution even after storage under cyclic heating and cooling, to provide a treatment liquid-housing article that houses the treatment liquid, and to provide a pattern forming method and an electronic device production method that use the treatment liquid. The treatment liquid of the invention is a treatment liquid containing propylene glycol monomethyl ether acetate, water, and an organic acid. The content of propylene glycol monomethyl ether acetate is 60% by mass or more based on the total mass of the treatment liquid, and the content of water is 1 to 100 ppm by mass based on the total mass of the treatment liquid. The content of the organic acid is 1.00% by mass or more and less than 40.00% by mass based on the total mass of the treatment liquid, and the ratio of the content mass of the organic acid to the content mass of water is 100 to 100000.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a treatment liquid and a treatment liquid-housing article.

2. Description of the Related Art

Conventional processes for producing semiconductor devices such as ICs (Integrated Circuits) and LSI (Large Scale Integrated) circuits involve lithographic microfabrication using a photoresist composition. In recent years, as the degree of integration of integrated circuits has increased, there has been a growing demand for ultra-fine pattern formation in the sub-micron or quarter-micron range. Accordingly, the wavelength of exposure light tends to be shortened. Specifically, the g-line is replaced by the i-line and further by KrF excimer laser light. Moreover, at present, in addition to the use of excimer laser light, lithography using electron beams, X-rays, EUV (extreme ultraviolet) rays, etc. is being developed.

In the lithography described above, a film (resist film) is formed using an actinic ray-sensitive or radiation-sensitive composition (which is referred to also as a “resist composition”), and then the obtained film is subjected to the following treatment. Specifically, the film is exposed to light and developed using a developer, and the developed film is washed with a rinsing liquid.

As the developer used for the lithography described above, JP2022-526031A, for example, discloses a developer composition used for developing treatment for an organometallic patterning layer. This developer composition contains a solvent having a value of Hansen solubility parameters δH+δP of about 16 (J/cm3)1/2 or less in an amount of at least 55% by volume and a solvent having a value of Hansen solubility parameters δH+δP of about 16 (J/cm3)1/2 in an amount of at least 0.25 to 45% by volume.

SUMMARY OF THE INVENTION

The inventors have conducted studies on the developer composition disclosed in JP2022-526031A. The inventors have found that, when the developer composition is used as a developer or a rinsing liquid for a metal resist, at least one of the ability to suppress the occurrence of defects in the obtained pattern (which may be hereinafter referred to simply as the “ability to suppress the occurrence of pattern defects”), pattern resolution, the ability to suppress the occurrence of defects originating from the treatment liquid after storage under cyclic heating and cooling, or pattern resolution after storage under cyclic heating and cooling deteriorates, and there is room for improvement.

The deterioration of the ability to suppress the occurrence of defects originating from the treatment liquid after storage under cyclic heating and cooling and the deterioration of the pattern resolution after storage under cyclic heating and cooling mean the following phenomenon. The treatment liquid is stored at a high temperature (e.g., 85° C.) for a prescribed time (e.g., 1 hour) and then stored at a lower temperature (e.g., 5° C.) for a prescribed time (e.g., 1 hour). This procedure is defined as one cycle. While this cycle is repeated, the treatment liquid is stored under cyclic heating and cooling for a prescribed period (e.g., one month). The deterioration phenomenon is that, when the resulting treatment liquid is used, the ability to suppress the occurrence of defects originating from the treatment liquid and the pattern resolution after storage under cyclic heating and cooling are poorer than those before storage under cyclic heating and cooling. It is preferable to suppress this phenomenon.

Accordingly, it is an object of the invention to provide a treatment liquid that, when used as a developer or a rinsing liquid for a metal resist, exhibits a high ability to suppress the occurrence of pattern defects and a high pattern resolution and exhibits a high ability to suppress the occurrence of defects originating from the treatment liquid even after storage under cyclic heating and cooling and a high pattern resolution even after storage under cyclic heating and cooling.

It is another object of the invention to provide a treatment liquid-housing article that houses the treatment liquid.

The inventors have conducted extensive studies to solve the foregoing problem and found that the problem can be solved by the following aspects.

[2] The treatment liquid according to [1], wherein the ratio of the content mass of the organic acid to the content mass of the water is 1000 to 10000.

[3] The treatment liquid according to [1] or [2], wherein the content of the propylene glycol monomethyl ether acetate is 80% by mass or more based on the total mass of the treatment liquid, and

[4] The treatment liquid according to any one of [1] to [3], wherein the organic acid includes at least one organic acid selected from the group consisting of formic acid, acetic acid, propionic acid, butyric acid, and lactic acid.

[5] The treatment liquid according to any one of [1] to [4], further including boron atoms,

[6] The treatment liquid according to any one of [1] to [5], further including Pb atoms,

[7] The treatment liquid according to any one of [1] to [6], wherein the treatment liquid is used as a developer for a metal resist or a rinsing liquid for a metal resist.

[8] A treatment liquid-housing article including: a container; and the treatment liquid according to any one of [1] to [7], the treatment liquid being housed in the container.

[9] The treatment liquid-housing article according to [8], wherein the container has a liquid-contacting portion that is in contact with the treatment liquid and that is formed of a nonmetallic material or stainless steel.

[10] The treatment liquid-housing article according to [9], wherein the nonmetallic material is at least one selected from the group consisting of polyethylene resins, polypropylene resins, polyethylene-polypropylene resins, tetrafluoroethylene resins, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, tetrafluoroethylene-hexafluoropropylene copolymer resins, tetrafluoroethylene-ethylene copolymer resins, chlorotrifluoroethylene-ethylene copolymer resins, vinylidene fluoride resins, chlorotrifluoroethylene copolymer resins, and vinyl fluoride resins.

The present invention can provide a treatment liquid that, when used as a developer or a rinsing liquid for a metal resist, exhibits a high ability to suppress the occurrence of pattern defects and a high pattern resolution and exhibits a high ability to suppress the occurrence of defects originating from the treatment liquid even after storage under cyclic heating and cooling and a high pattern resolution even after storage under cyclic heating and cooling.

The present invention can also provide a treatment liquid-housing article that houses the treatment liquid.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will next be described in detail.

The structural requirements described below may be described on the basis of representative embodiments of the present invention. However, the invention is not limited to these embodiments.

In the present specification, a numerical range represented using “to” means a range including the numerical values before and after the “to” as the lower limit and the upper limit, respectively.

In the present specification, “actinic rays” or “radiation” means, for example, an emission line spectrum of a mercury lamp, far-ultraviolet rays typified by excimer laser light, extreme ultraviolet light (EUV light), X-rays, electron beams (EB), etc. In the present specification, “light” means actinic rays or radiation.

In the present specification, “exposure to light” is intended to encompass not only exposure to an emission line spectrum of a mercury lamp, far-ultraviolet rays typified by excimer laser light, X-rays, EUV light, etc. but also image drawing using an electron beam or a particle beam such as an ion beam.

A substituent is preferably a monovalent substituent unless otherwise specified.

In the present specification, no limitation is imposed on the bonding direction of a divalent group, unless otherwise specified. For example, when Y in a compound represented by a formula “X—Y—Z” is —COO—, Y may be —CO—O— or may be —O—CO—. This compound may be “X—CO—O—Z” or may be “X—O—CO—Z.”

In the present specification, a halogen atom is, for example, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

In the present specification, solids mean components forming a metal resist film and do not include a solvent (such as an organic solvent or water). Any component included in a metal resist film is regarded as a solid even when it is in a liquid form.

In the present specification, when two or more types of component are present, the “content” of the component means the total content of the two or more types of component.

The treatment liquid of the invention, the treatment liquid-housing article of the invention, the pattern forming method of the invention, and the electronic device production method of the invention will be described successively.

The treatment liquid of the invention will be described in detail.

The treatment liquid of the invention is a treatment liquid containing propylene glycol monomethyl ether acetate (which is hereinafter referred to also as “PGMEA”), water, and an organic acid. The content of PGMEA is 60% by mass or more based on the total mass of the treatment liquid, and the content of water is 1 to 100 ppm by mass based on the total mass of the treatment liquid. The content of the organic acid is 1.00% by mass or more and less than 40.00% by mass based on the total mass of the treatment liquid, and the ratio of the content mass of the organic acid to the content mass of water (which is hereinafter referred to also as a “specific mass ratio”) is 100 to 100000.

The reason that the treatment liquid having the composition described above can solve the problem in the invention is not always clear. However, the inventors infer that the reason is as follows.

The following inference does not limit the mechanism that produces the above-described effects. In other words, even when the effects are obtained through a mechanism other than the following mechanism, this mechanism is included in the scope of the invention.

The treatment liquid contains the prescribed amount of PGMEA, which is an organic solvent having the ability to dissolve a metal resist in unexposed portions, and the prescribed amount of the organic acid that facilitates the dissolution of the metal resist in the unexposed portions and therefore exhibits a high pattern resolution. Moreover, since the water content is controlled, the physical properties of the treatment liquid are adjusted appropriately, and the occurrence of pattern defects can be suppressed. This may be the reason that the desired effects are obtained when the treatment liquid is used as a developer or a rinsing liquid for a metal resist.

The phrase “the effects of the invention are further enhanced” means that at least one of the ability to suppress the occurrence of pattern defects, the pattern resolution, the ability to suppress the occurrence of defects originating from the treatment liquid after storage under cyclic heating and cooling, or the pattern resolution after storage under cyclic heating and cooling is further enhanced.

The treatment liquid contains PGMEA.

The content of PGMEA is 60% by mass or more based on the total mass of the treatment liquid. The content of PGMEA is preferably 65% by mass or more, more preferably 70% by mass or more, and still more preferably 80% by mass or more because better pattern resolution can be obtained. The upper limit of the content of PGMEA is preferably less than 99% by mass and more preferably 95% by mass or less based on the total mass of the treatment liquid.

If the content of PGMEA is less than 60% by mass based on the total mass of the treatment liquid, the ability of the treatment liquid to dissolve a metal resist film is low, and the pattern resolution decreases, which is not preferred.

The treatment liquid contains water.

The lower limit of the content of water is 1 ppm by mass or more, preferably 3 ppm by mass or more, and more preferably 5 ppm by mass or more based on the total mass of the treatment liquid because the ability to suppress the occurrence of pattern defects can be higher.

When the content of water is within the above range, the ability to suppress the occurrence of pattern defects is improved. Although the reason for this is unclear, the reason may be as follows. Since the electric conductivity of the treatment liquid is high, the occurrence of a spark that causes dielectric breakdown of a material in contact with the treatment liquid is reduced, so that mixing of foreign substances that may cause defects can be prevented.

The upper limit of the water content is 100 ppm by mass or less, preferably 80 ppm by mass or less, and more preferably 50 ppm by mass or less based on the total mass of the treatment liquid because the ability to suppress the occurrence of pattern defects can be higher and the occurrence of defects and deterioration of pattern resolution after storage under cyclic heating and cooling can be further suppressed.

When the content of water is within the above range, the ability to suppress the occurrence of pattern defects is improved. Although the reason for this is unclear, the reason may be as follows. Since the electric conductivity of the treatment liquid is high, the occurrence of a spark that causes dielectric breakdown of a material in contact with the treatment liquid is reduced, so that mixing of foreign substances that may cause defects can be prevented.

When the water content is within the above range, the occurrence of defects caused by water (such as water mark defects) can be reduced, and an unintended reaction of components of the treatment liquid during storage under cyclic heating and cooling can be suppressed.

The content of water can be measured using a device that uses a Karl Fischer moisture measurement method as the measurement principle. The device used may be, for example, a Karl Fischer moisture meter (product name: “MKC-710M” manufactured by Kyoto Electronics Manufacturing Co., Ltd., Karl Fischer coulometric titration type).

Examples of the water include distilled water, ion exchanged water, pure water, and ultrapure water, and ultrapure water is preferred.

The water may be intentionally added water, may be water inevitably contained in the raw materials of the treatment liquid, or may be water inevitably mixed during the production, storage, and/or transportation of the treatment liquid.

No particular limitation is imposed on the method for controlling the water content. A method in which water is removed from the treatment liquid and/or the raw materials used to prepare the treatment liquid, a method in which water is added, or a combination of these methods may be used.

The method for removing water may be any well-known dewatering method, and examples include dewatering using a water adsorbent, distillation, and dewatering using a dewatering membrane.

Examples of the water adsorbent include zeolite (such as a molecular sieve), sodium sulfate, magnesium sulfate, silica gel, calcium chloride, anhydrous zinc chloride, fuming sulfuric acid, and soda lime.

Examples of the dewatering method using a dewatering membrane include membrane dewatering by pervaporation (PV) or vapor permeation (VP). Examples of the dewatering membrane include membranes formed of polymer-based materials such as polyimide-based, cellulose-based, and polyvinyl alcohol-based materials and membranes formed of inorganic-based materials such as zeolite.

The treatment liquid contains an organic acid.

The organic acid may be dissociated in the treatment liquid or may form a salt.

The content of the organic acid is 1.00% by mass or more based on the total mass of the treatment liquid and is preferably 3.00% by mass or more and more preferably 5.00% by mass or more because a higher pattern resolution can be achieved.

The content of the organic acid is less than 40.00% by mass based on the total mass of the treatment liquid and is preferably less than 30.00% by mass and more preferably less than 20.00% by mass because a higher pattern resolution can be achieved.

If the content of the organic acid is less than 1.00% by mass or 40.00% by mass or more based on the total mass of the treatment liquid, the ability of the treatment liquid to dissolve a metal resist is low, and the pattern resolution deteriorates, which is not preferred.

From the viewpoint of achieving a higher pattern resolution, the content of propylene glycol monomethyl ether acetate is preferably 80% by mass or more based on the total mass of the treatment liquid, and the content of the organic acid is preferably 1.00% by mass or more and less than 20.00% by mass based on the total mass of the treatment liquid.

From the viewpoint of achieving a higher pattern resolution, the ratio of the content mass of the organic acid with respect to the content mass of PGMEA (the content mass of the organic acid/the content mass of PGMEA) is preferably 0.03 to 0.5 and more preferably 0.03 to 0.2.

Examples of the organic acid include: carboxy acid-based organic acids such as aliphatic carboxylic acid-based organic acids and aromatic carboxylic acid-based organic acids; and phosphonic acid-based organic acids. Of these, carboxy acid-based organic acids are preferred, and monocarboxylic acids are more preferred.

The carboxy acid-based organic acid is a compound having one or two or more carboxy groups.

The carboxy acid-based organic acid may further have a hydroxy group in addition to the carboxy group(s).

The number of carboxy groups included in the carboxy acid-based organic acid is preferably 1 to 10, more preferably 1 to 5, and still more preferably 1.

Examples of the phosphonic acid-based organic acid include compounds described in paragraphs [0026] to [0036] of WO2018/020878A and compounds described in paragraphs [0031] to [0046] of WO2018/030006A, and the entire contents of these documents are incorporated herein.

The melting point of the organic acid is preferably 20° C. or lower, more preferably 18° C. or lower, and still more preferably 16° C. or lower. The lower limit of the melting point is preferably −20° C. or higher.

Preferably, the organic acid includes at least one organic acid selected from the group consisting of formic acid, acetic acid, propionic acid, butyric acid, and lactic acid.

Only one organic acid may be used, or two or more organic acids may be used.

In the treatment liquid, the specific mass ratio (the content mass of the organic acid/the content mass of water) is 100 to 100000, preferably 500 to 50000, and more preferably 1000 to 10000.

The treatment liquid may contain propylene glycol monomethyl ether (hereinafter referred to also as “PGME”).

The content of PGME is preferably 0.0001% by mass or more based on the total mass of the treatment liquid and is more preferably 0.0005% by mass or more and still more preferably 0.001% by mass or more because the ability to suppress the occurrence of pattern defects can be higher and the deterioration of the pattern resolution after storage under cyclic heating and cooling can be further suppressed.

The content of PGME is preferably 0.1% by mass or less based on the total mass of the treatment liquid and is more preferably 0.05% by mass or less and still more preferably 0.02% by mass or less because the ability to suppress the occurrence of pattern defects can be higher and the deterioration of the ability to suppress the occurrence of defects after storage under cyclic heating and cooling can be further reduced.

The total content of PGMEA, water, and the organic acid in the treatment liquid is preferably 95% by mass or more, more preferably 99% by mass or more, still more preferably 99.9% by mass or more, and particularly preferably 99.99% by mass or more based on the total mass of the treatment liquid. The upper limit of the total content is, for example, 100% by mass or less and is less than 100% by mass in many cases.

The total content of PGMEA, water, the organic acid, and PGME in the treatment liquid is preferably 95% by mass or more, more preferably 99% by mass or more, still more preferably 99.9% by mass or more, and particularly preferably 99.99% by mass or more based on the total mass of the treatment liquid. The upper limit of the total content is, for example, 100% by mass or less and is less than 100% by mass in many cases.

The treatment liquid may contain boron atoms.

It is preferable that the treatment liquid contains boron atoms because the number of defects originating from alkali metals and alkaline-earth metals can be reduced.

No particular limitation is imposed on the form of boron atoms in the treatment liquid. Examples of the form of boron atoms include boron-containing compounds such as inorganic boron compounds and organic boron compounds and elemental boron. The boron atoms may be present as ions in the treatment liquid.

Examples of the inorganic boron compound include boric acid (H3BO3), borates, and metal borides.

In particular, the boron atoms are often in the form of boric acid or a borate. Examples of the borate include alkali metal salts such as a sodium salt and a potassium salt and alkaline-earth metal salts such as a calcium salt and a magnesium salt.

The boron atoms may be those intentionally added, may be those inevitably contained in the raw materials of the treatment liquid, or may be those inevitably mixed during production, storage, and/or transportation of the treatment liquid.

No particular limitation is imposed on the method for controlling the content of boron atoms. Examples of the method include a method in which boron atoms are removed from the treatment liquid and/or the raw materials used to prepare the treatment liquid, a method in which a component containing boron atoms (a boron atom source) is added, and a combination of these method.

Examples of the removal of boron atoms from the treatment liquid and/or the raw materials used to prepare the treatment liquid include removal of boron-containing compounds, elemental boron, ions containing boron atoms, etc. from the treatment liquid and/or the raw materials used to prepare the treatment liquid.

In particular, a method in which a boron atom source is added to a mixture of the raw materials from which boron atoms have been removed is preferred because the composition can be easily controlled.

Any well-known boron atom removal method may be appropriately selected according to the form of boron atoms in the treatment liquid and/or the raw materials used to prepare the treatment liquid. Examples of the method include purification treatment such as ion removal treatment and filtration treatment described later, and anion exchange treatment is preferred.

No particular limitation is imposed on the boron atom source. For example, elemental boron and the boron-containing compounds described above can be used, and elemental boron, boric acid, and borates are preferred.

The content of boron atoms is preferably 0.001 to 100 ppt by mass based on the total mass of the treatment liquid and is more preferably 0.002 to 85 ppt by mass, still more preferably 0.01 to 75 ppt by mass, and particularly preferably 0.05 to 50 ppt by mass because the number of defects originating from alkali metals and alkaline-earth metals can be reduced.

The content of boron atoms is measured by ICP-MS (inductively coupled plasma mass spectrometry).

Examples of the device used for ICP-MS include an Agilent 8900 triple quadrupole ICP-MS (inductively coupled plasma mass spectrometry for semiconductor analysis, option: #200) manufactured by Agilent Technologies Japan, Ltd., NexION 350S manufactured by PerkinElmer, and Agilent 8800 manufactured by Agilent Technologies Japan, Ltd.

When the content of boron atoms is measured, the measurement may be performed after the treatment liquid is concentrated. The treatment liquid is concentrated as follows.

A container used for concentration is a polytetrafluoroethylene-made container.

First, ultrapure water is added to the treatment liquid to be subjected to quantification of boron atoms. The content of boron atoms in the ultrapure water is measured in advance. When, for example, the boron atoms are boron, it is expected from a potential-pH diagram of a water-boron system that the boron is present in the form of boric acid in the ultrapure water.

Next, the treatment liquid with the ultrapure water added thereto is heated to convert the boron present in the treatment liquid to boric acid. Then the treatment liquid subjected to the above heating treatment is concentrated.

When the treatment liquid with the ultrapure water added thereto is heated, the treatment liquid is heated at a temperature of 100° C. for 1 hour under reflux conditions.

When the concentration is performed, the organic solvent and water contained in the treatment liquid are removed at 160 to 180° C.

When the content of boron atoms in the ultrapure water is measured, the measurement may be performed after the ultrapure water is concentrated. To concentrate the ultrapure water, the method for concentrating the treatment liquid described above may be referred to.

During the concentration, the contents of boron atoms in chemical solutions with different concentration factors from 10 to 1000 are computed. When positive correlation (positive first-order correlation) is found between the concentration factor and the content of boron atoms, the contents of boron atoms contained in the chemical solutions can be quantified by the method described above.

The treatment liquid may contain at least one type of metal atoms (hereinafter referred to also as “specific metal atoms”) selected from the group consisting of Pb (lead), Fe (iron), Cr (chromium), Ni (nickel), and Sn (tin).

Preferably, the specific metal atoms include Pb atoms.

Preferably, the treatment liquid contains the specific metal atoms because the occurrence of defects originating from a coating solution when the treatment liquid is applied to a substrate can be suppressed (in other words, because “the ability to suppress the occurrence of defects originating from the treatment liquid can be higher”).

No particular limitation is imposed on the form of the specific metal atoms in the treatment liquid. The specific metal atoms may be contained as metal particles or as metal ions.

The metal particles may be in the form of single substance particles composed of the specific metal atoms, in the form of particles of an alloy of the specific metal atoms and other metal atoms, or in the form of particles composed of the specific metal atoms combined with an organic substance. The metal ions may form a salt and/or a complex.

The specific metal atoms may be those intentionally added, may be those inevitably contained in the raw materials of the treatment liquid, or may be those inevitably mixed during the production, storage, and/or transportation of the treatment liquid.

No particular limitation is imposed on the method for controlling the content of the specific metal atoms. A method in which the specific metal atoms are removed from the treatment liquid and/or the raw materials used to prepare the treatment liquid, a method in which a component containing the specific metal atoms (a specific metal atom source) is added, or a combination of these methods may be used.

Examples of the removal of the specific metal atoms from the treatment liquid and/or the raw materials used to prepare the treatment liquid include removal of metal particles, metal ions, etc. from the raw materials.

In particular, a method in which a specific metal atom source is added to a mixture of the raw materials from which the specific metal atoms have been removed is preferred because the composition can be easily controlled.

To remove the specific metal atoms, any well-known method may be appropriately selected according to the form of the specific metal atoms in the treatment liquid and/or the raw materials used to prepare the treatment liquid. Examples of the method include purification treatment such as ion removal treatment and filtration treatment described later. When the specific metal atoms are in the form of metal particles, the filtration treatment is preferred. When the specific metal atoms are in the form of metal ions, the ion removal treatment is preferred.

No particular limitation is imposed on the specific metal atom source. Examples of the specific metal atom source include metal particles such as metal nanoparticles, metal oxide particles, and metal ion-containing compounds such as metal salts (e.g., metal halides) and organic metal complexes, and metal nanoparticles are preferred.

The treatment liquid may contain one type of specific metal atoms or may contain two or more types.

The content of the specific metal atoms is preferably 0.001 ppt by mass or more, more preferably 0.005 ppt by mass or more, still more preferably 0.01 ppt by mass or more, and particularly preferably 0.05 ppt by mass or more based on the total mass of the treatment liquid because the ability to suppress the occurrence of defects originating from the treatment liquid can be higher.

The reason that the ability to suppress the occurrence of defects originating from the treatment liquid is high when the content of the specific metal atoms is within the above range is unclear. However, the reason may be as follows. The specific metal atoms serve as a carrier for electric charges generated by triboelectrification etc., and therefore the occurrence of a spark that causes dielectric breakdown of a material in contact with the treatment liquid is reduced, so that mixing of foreign substances that may cause defects can be prevented.

The content of the specific metal atoms is preferably 200 ppt by mass or less, more preferably 10 ppt by mass or less, still more preferably 7.5 ppt by mass or less, and particularly preferably 5 ppt by mass or less based on the total mass of the treatment liquid because the ability to suppress the occurrence of defects originating from the treatment liquid can be higher.

In particular, the content of the specific metal atoms is preferably 0.001 to 7.5 ppt by mass, more preferably 0.05 to 7.5 ppt by mass, and still more preferably 0.01 to 5.0 ppt by mass based on the total mass of the treatment liquid.

When the content of the specific metal atoms is within the above range, the occurrence of nanoparticle defects originating from the specific metal atoms can be suppressed.

The type of specific metal atoms and their content can be measured by ICP-MS. The device that can be used for the ICP-MS is as described above.

When the type of specific metal atoms and their content are measured, the measurement may be performed after the treatment liquid is concentrated. The treatment liquid can be concentrated using the same procedure as the concentration procedure for measuring the content of boron atoms.

The treatment liquid may contain an additional component other than the components described above.

Examples of the additional component include a surfactant.

The surfactant used may be any well-known surfactant, and examples include nonionic surfactants and fluorine-based surfactants.

Compounds exemplified in paragraph [0126] of WO2022/044893 can be used as the surfactant.

[Physical Properties of Treatment Liquid]

<Metal Atoms Other than Specific Metal Atoms>

In the treatment liquid, the contents of metal atoms (such as Co, Na, Cu, Mg, Mn, Li, Al, and Ag) other than the specific metal atoms are each preferably 1000 ppt by mass or less and more preferably 500 ppt by mass or less. In the production of the most advanced semiconductor elements, it is expected that even higher purity chemical solutions are required. Therefore, the contents of the metal atoms other than the specific metal atoms are each more preferably less than 500 ppt by mass, particularly preferably 150 ppt by mass or less, and most preferably less than 100 ppt by mass. The lower limit is preferably 0.

Examples of the method for reducing the contents of the metal atoms other than the specific metal atoms include purification treatment such as filtration treatment, ion removal treatment, and distillation treatment described later.

Other examples include a method in which a container from which the dissolution of metal components is small is used as a container for storing the raw materials or the produced treatment liquid and a method in which the inner walls of pipes used during the production of the treatment liquid are lined with a fluorocarbon resin in order to prevent the dissolution of the metal components from the pipes.

The treatment liquid may contain coarse particles, but it is preferable that the content of the coarse particles is small.

The coarse particles mean particles having a diameter (particle size) of 1 μm or more when the shape of each particle is assumed to be spherical.

The coarse particles contained in the treatment liquid are particles such as dust, dirt, organic solids, and inorganic solids that are contained in the raw materials as impurities and particles such as dust, dirt, organic solids, and inorganic solids that are brought into the treatment liquid as contaminants during its preparation. The coarse particles do not dissolve in the final treatment liquid and are present as particles.

As for the content of the coarse particles in the treatment liquid, the number of particles with a diameter of 1 μm or more is preferably 100 or less per 1 mL of the treatment liquid and more preferably 50 or less per 1 mL of the treatment liquid. The lower limit of the content is preferably 0.

The content of the coarse particles in the treatment liquid can be measured in its liquid phase using a commercial measurement device that uses a laser as a light source and a light scattering type in-liquid particle measurement method.

Examples of the method for removing the coarse particles include purification treatment such as filtration treatment described later.

The treatment liquid is preferably used as a developer or a rinsing liquid for a metal resist.

Other examples of the applications include metal resist washing solutions such as edge bead removers, filter washing solutions, pipe washing solutions, and tank washing solutions.

To avoid the dissolution of a pattern formed using a metal resist composition, it is preferable that the ability of the treatment liquid used as a rinsing liquid to dissolve the metal resist film is lower than that of the developer. The “ability of the developer or rinsing liquid to dissolve the metal resist” is an indicator indicating the ease of dissolution of the metal resist film in the developer or rinsing liquid. For example, equal amounts of two different treatment liquids are supplied to metal resist films. Then one of the two treatment liquids that dissolves a smaller amount of the metal resist film (causes a smaller reduction in the volume of the metal resist film) per unit time is the treatment liquid whose ability to dissolve the metal resist film is smaller.

In general, the dissolving ability of the developer is such that the metal resist film in exposed portions does not dissolve. However, when the dissolving ability of the rinsing liquid used is higher than that of the developer, it is feared that the metal resist film in the exposed portions may dissolve and the pattern shape may collapse. Moreover, in some regions of the exposed portions in which the metal resist film is present, the polymerization reaction may be less likely to progress than in the other regions of the resist film in the exposed portions. These regions may more easily dissolve in an organic solvent. In this case, when the ability of the rinsing liquid to dissolve the metal resist film is the same as that of the developer, it is feared that these regions may dissolve slightly and the shape of the pattern may collapse. However, the collapse of the pattern may be prevented by using, as the rinsing liquid, a treatment liquid whose ability to dissolve the metal resist film is lower than that of the developer.

When the treatment liquid of the invention is used as a developer and then a rinsing liquid is used for washing, no particular limitation is imposed on the rinsing liquid so long as it is a treatment liquid or rinsing liquid whose ability to dissolve the metal resist film is lower than that of the developer.

The rinsing liquid may be a mixture of two or more organic solvents.

When the developer is the treatment liquid of the invention, the rinsing liquid is, for example, 2-heptanone, methyl isobutyl carbinol (MIBC), PGMEA, PGME (propylene glycol monomethyl ether), a mixture of PGMEA and PGME, or nBA (n-butyl acetate).

The rinsing liquid may be purified using a purification method described later for various components contained in the treatment liquid.

The treatment liquid can be produced using any well-known method. For example, the treatment liquid can be produced by mixing the components described above such that prescribed concentrations are obtained. No particular limitation is imposed on the order in which these components are mixed.

To remove excess portions of the components and/or impurities, the raw materials of the treatment liquid and/or a mixture of the raw materials may be subjected to purification treatment. In particular, it is preferable that PGMEA, water, and the organic acid used to produce the treatment liquid are products obtained by subjecting materials to be purified containing these components to purification treatment. When a treatment liquid containing boron atoms or the specific metal atoms described above in a prescribed amount is produced, it is preferable to produce the treatment liquid containing the prescribed components as follows. Unpurified products containing the above-described components (PGMEA, water, and the organic acid) are subjected to purification treatment to reduce the amounts of impurities such as boron atoms and the specific metal atoms, and the resulting raw materials are mixed to obtain a solution mixture. Then prescribed amounts of boron atoms and/or the specific metal atoms are supplied to the solution mixture. In this case, by subjecting the unpurified products containing the components used (PGMEA, water, and the organic acid) to purification treatment, the amount of impurities other than boron atoms and the specific metal atoms can also be reduced.

The unpurified products may be, for example, purchased or may be synthesized by reacting their precursors.

It is preferable that the content of impurities in the unpurified products is low. Examples of commercial products that meet this requirement include commercial products called “high purity grade products.”

No particular limitation is imposed on the method for synthesizing an unpurified product by reacting its precursor, and any well-known method can be used. In one exemplary method, one or more raw materials are reacted in the presence of a catalyst to obtain a reaction product, i.e., PGME or PGMEA.

For example, a method described in JP2011-509998A can be used as the method for synthesizing an unpurified product containing PGME.

In one method for synthesizing an unpurified product containing PGMEA, PGME and acetic acid used as raw materials are reacted in the presence of an acid catalysis. Specifically, a method described in JP1984-176232A (JP-S59-176232A) and a method described in JP2001-521918A can be used.

When PGMEA is repeatedly subjected to ion removal treatment described later, the PGMEA may undergo a decomposition reaction. Therefore, it is preferable that a product subjected to ion removal treatment in advance is used as a raw material (specifically, PGME) used to synthesize an unpurified product containing PGMEA.

To purify an unpurified product, any well-known method can be used. Examples of the purification method include filtration treatment, ion removal treatment, and distillation treatment.

To purify an unpurified product, a combination of a plurality of types of treatment selected from the group consisting of filtration treatment, ion removal treatment, and distillation treatment may be performed. For example, after primary purification in which an unpurified product is distilled, the resulting unpurified product may be subjected to secondary purification in which the unpurified product is caused to pass through an ion exchange resin and/or a filter. Alternatively, after primary purification in which an unpurified product is caused to pass through an ion exchange resin and/or a filter, the resulting unpurified product may be subjected to secondary purification in which the resulting unpurified product is distilled.

Each purification treatment may be repeated a plurality of times.

No particular limitation is imposed on the filtration treatment method, and any well-known method can be used. In particular, it is preferable to use filtration treatment in which an unpurified product is filtered using a filter. No particular limitation is imposed on the components removed by the filtration treatment, and examples of the components include metal particles and coarse particles.

No particular limitation is imposed on the filter used for the filtering, and any well-known filter can be used.

Examples of the material of the filter include fluorocarbon resins such as PTFE (polytetrafluoroethylene) and PFA (perfluoroalkoxyalkane), polyamide-based resins such as 6-nylon and 6,6-nylon, polyolefin resins (including high-density and ultrahigh-molecular weight polyolefin resins) such as polyethylene and polypropylene, diatomaceous earth, and glass. In particular, PTFE, polyamide-based resins, UPE (ultrahigh-density polyethylene), HDPE (high-density polyethylene), and HDPP (high-density polypropylene) or UHDPP (ultrahigh-density polypropylene) are preferred. By using a filter formed of any of these materials, highly polar foreign substances and metallic impurities that are likely to cause particle defects can be removed more effectively.

The critical surface tension of the filter is preferably 70 to 95 mN/m and more preferably 75 to 85 mN/m. The value of the critical surface tension used may be the manufacturer's nominal value.

When the critical surface tension of the filter used is within the above range, highly polar foreign substances and metallic impurities that are likely to cause particle defects can be removed more effectively.

The pore diameter of the filter is preferably 0.1 nm to 1.0 μm, more preferably 0.5 nm to 0.1 μm, and still more preferably 1.0 to 50.0 nm. When the pore diameter of the filter is within the above range, fine foreign substances contained in the unpurified product can be removed effectively while clogging of the filter is prevented.

The filter may have been subjected to surface treatment. No particular limitation is imposed on the surface treatment method, and any well-known method can be used. Examples of the surface treatment include chemical modification treatment, plasma treatment, hydrophobic treatment, coating, gas treatment, and sintering. Of these, chemical modification treatment or plasma treatment is preferred.

The chemical modification treatment is preferably treatment in which ion exchange groups are introduced. Specifically, the filter may be an ion exchange filter.

Examples of the ion exchange group include: cation exchange groups such as a sulfonate group, a carboxy group, and a phosphate group; and anion exchange groups such as a quaternary ammonium group. No particular limitation is imposed on the method for introducing the ion exchange groups into the filter. In one exemplary method, a compound including an ion exchange group and a polymerizable group is reacted and grafted with a polymer contained in the filter.

The filtering may be multistage filtration treatment in which the unpurified product is caused to pass through two or more filters different in at least one selected from the group consisting of filter material, pore diameter, and pore structure. Alternatively, the unpurified product may be caused to pass through the same filter a plurality of times or may be caused to pass through a plurality of filters of the same type.

In particular, circulating filtration treatment is preferred in which a filtration device including a combination of a plurality of filters and a return passage is used to cause the unpurified product to pass through the filters a plurality of times.

No particular limitation is imposed on the number of times the circulating filtration is repeated. The number of repetitions may be appropriately selected according to the intended purity and impurities and is preferably 2 to 100, more preferably 20 to 80, and still more preferably 30 to 70.

No particular limitation is imposed on the number of filters used in combination, and the number of filters is preferably 1 to 10 and more preferably 2 to 5.

When the filtering is performed using a combination of different filters, it is preferable that the pore diameter of the filter that first comes into contact with the liquid is larger than or equal to the pore diameter of the filter that subsequently comes into contact with the liquid. The nominal value of each filter provided by the manufacturer can be used for the pore diameter of the filter.

Examples of the commercial filter include various filters available from Nihon Pall Ltd., Advantec Toyo Kaisha, Ltd., Nihon Entegris G. K., KITZ MICROFILTER CORPORATION, etc., and the filters used can be selected from these filters.

The temperature during filtering is preferably 25° C. or lower, more preferably 23° C. or lower, and still more preferably 20° C. or lower. The lower limit is preferably 0° C. or higher, more preferably 5° C. or higher, and still more preferably 10° C. or higher. When the temperature during filtering is within the above range, particulate foreign substances and impurities dissolved in the treatment liquid precipitate and can be removed efficiently.

The ion removal treatment is treatment in which an unpurified product is subjected to ion exchange treatment or ion adsorption treatment using chelating groups. No particular limitation is imposed on the components removed by the ion removal treatment, but examples thereof include acids and metal ions.

No particular limitation is imposed on the ion exchange treatment method, and any well-known method can be used. Examples of the method include a method in which the unpurified product is brought into contact with an ion exchange resin. A method in which the unpurified product is caused to pass through a packed section packed with the ion exchange resin is preferred.

In the ion exchange treatment, the unpurified product may be caused to pass through the same ion exchange resin a plurality of times or may be caused to pass through different ion exchange resins.

Examples of the ion exchange resin include anion exchange resins and cation exchange resins.

When both a cation exchange resin and an anion exchange resin are used, the unpurified product may be caused to pass through a packed section packed with a resin mixture containing these resins or may be caused to pass through a plurality of packed sections packed with respective resins.

The anion exchange resin used may be any well-known anion exchange resin, and it is preferable to use a gel-type anion exchange resin.

Examples of the anion exchange resin include strongly basic anion exchange resins having quaternary ammonium groups and weakly basic anion exchange resins having amino groups.

The anion exchange resin used may be an anion exchange resin described in JP2009-155208A.

The cation exchange resin used may be any well-known cation exchange resin and is preferably a gel-type cation exchange resin.

Specific examples of the cation exchange resin include sulfonic acid-type cation exchange resins and carboxylic acid-type cation exchange resins.

No particular limitation is imposed on the ion adsorption treatment using chelating groups, and any well-known method can be used. Examples of the ion adsorption treatment include a method in which the unpurified product is caused to pass through a packed section packed with a chelating resin having a chelating group.

In the ion removal treatment, the unpurified product may be caused to pass through the same chelating resin a plurality of times or may be caused to pass through different chelating resins.

Examples of the chelating resin include resins having a chelating ability or a chelating group such as an amidoxime group, a thiourea group, a thiouronium group, iminodiacetic acid, amidophosphoric acid, phosphonic acid, aminophosphoric acid, aminocarboxylic acid, N-methylglucamine, an alkylamino group, a pyridine ring, cyclic cyanine, a phthalocyanine ring, or a cyclic ether.

The ion removal treatment may be used in combination with the filtration treatment described above. For example, a method may be used in which a column packed with an ion exchange resin is installed in the circulating filtration device described above and the untreated product is caused to continuously pass through the ion exchange resin-packed section and the filter.

No particular limitation is imposed on the distillation treatment method, and any well-known method can be used. Examples of the method include a method using a distillation column. No particular limitation is imposed on the components removed by the distillation process, and examples include acids, organic compounds, and water.

No particular limitation is imposed on the liquid-contacting portion of the distillation column. It is preferable that the liquid-contacting portion is formed from a corrosion-resistant material. Examples of the corrosion-resistant material include materials used for a treatment liquid-housing article described later.

In the distillation treatment, the unpurified product may be caused to pass through the same distillation column a plurality of times or may be caused to pass through different distillation columns.

When the unpurified product is caused to pass through different distillation columns, the following method, for example, may be used. The unpurified product is subjected to rough distillation treatment in which the unpurified product is caused to pass through a distillation column to remove low-boiling point acids etc. and then subjected to rectification treatment in which the resulting product is caused to pass through a distillation column different from the distillation column for the rough distillation treatment to remove acid components, other organic compounds, etc. Examples of the distillation column in the rough distillation treatment include a plate distillation column, and examples of the distillation column in the rectification treatment include a distillation column including at least one of a plate distillation column or a reduced pressure plate distillation column.

When the plate distillation column is used, the theoretical number of plates is preferably 50 or more and more preferably 100 or more. No particular limitation is imposed on the upper limit of the theoretical number of plates, but the number of plates is 200 or less in many cases.

For the purpose of achieving both thermal stability during distillation and precision of purification, reduced-pressure distillation may be used.

The distillation treatment used may be combined with at least one selected from the above-described filtration treatment and the above-described ion removal treatment. For example, the following method may be used. A distillation column is disposed on the primary side of a purification device used for the filtration treatment to introduce the distilled unpurified product into the purification device.

Purification treatment other than those described above such as dewatering treatment may be performed.

The dewatering treatment may be, for example, the water removal method described above.

It is preferable to produce the treatment liquid by the following method. An unpurified product containing PGMEA, an unpurified product containing water, and an unpurified product containing the organic acid are prepared, and the materials to be purified are each subjected to purification treatment. Then the unpurified products subjected to the purification treatment are mixed.

Preferably, the purification treatment includes at least the distillation treatment and the filtration treatment. In this case, no particular limitation is imposed on the order of the distillation treatment and the filtration treatment. The filtration treatment may be performed after the distillation treatment, or the distillation treatment may be performed after the filtration treatment.

In the filtration treatment, it is preferable to use at least one first filter selected from the group consisting of ion exchange filters and filters containing polyamide-based resins (such as Nylon filters) and at least one second filter selected from the group consisting of PTFE filters and UPE filters. The first filter can remove mainly ionic impurities etc., and the second filter can remove mainly particles (such as metal particles and fine organic particles) etc.

A plurality of first filters and a plurality of second filters may be used. In particular, it is preferable to use three or more second filters.

As described above, the filtration treatment performed may be circulating filtration treatment. The number of repetitions of the circulating filtration is as described above but is preferably 30 or more.

In the distillation treatment, it is preferable that the unpurified product is caused to pass through different distillation columns.

The amount of impurities contained in the raw materials of the treatment liquid can be reduced by the procedure described above, and the content of impurities in the treatment liquid produced can thereby be reduced.

It is preferable that the handling and production of the treatment liquid, the purification treatment, opening of a container of the treatment liquid, washing of the container and devices, filling of the treatment liquid, analysis, etc. are all performed in a clean room. Preferably, the cleanliness of the clean room is higher than or equal to class 4 defined in the international standard ISO 14644-1:2015 specified by the International Organization for Standardization. Specifically, the cleanliness of the clean room meets preferably ISO class 1, ISO class 2, ISO class 3, or ISO class 4, more preferably ISO class 1 or ISO class 2, or particularly preferably ISO class 1.

It is preferable that the handling, production, purification, housing, and storage of the treatment liquid are performed at 30° C. or lower because the performance of the treatment liquid can be maintained stably for a long time. The lower limit is preferably 5° C. or higher and more preferably 10° C. or higher.

The treatment liquid may be housed and stored in a container.

A combination of the container and the treatment liquid housed in the container is referred to as a treatment liquid-housing article.

The container may be purged in advance with an inert gas (such as nitrogen or argon) with a purity of 99.99995% by volume for the purpose of preventing deterioration of the components of the liquid during storage. The inert gas is preferably a gas with a small moisture content. The treatment liquid may be transported and/or stored at room temperature. However, the temperature may be controlled in the range of −20° C. to 20° C. in order to prevent deterioration.

The container used to house the treatment liquid may be any well-known container and is preferably a high-cleanliness container for semiconductor applications from which elution of impurities is low.

Examples of the container include the “Clean Bottle” series (manufactured by AICELLO CHEMICAL CO., LTD.) and “Pure bottles” (manufactured by KODAMA PLASTICS Co., Ltd.). From the viewpoint of preventing mixing of impurities (contaminants) into the raw materials and the treatment liquid, it is also preferable to use a multilayer container in which its inner wall has a six-layer structure formed of six resins or a multilayer container having a seven-layer structure formed of seven resins.

Examples of the multilayer container include containers described in JP2015-123351A, the entire contents of which are incorporated herein by reference.

Preferably, liquid-contacting portions (such as the container inner wall, the inlet for the treatment liquid, and the outlet for the treatment liquid) of the container that are to be in contact with the treatment liquid are formed of a nonmetallic material in order to prevent contamination.

No particular limitation is imposed on the nonmetallic material, and any well-known material can be used. Examples of the nonmetallic material include polyethylene resins, polypropylene resins, polyethylene-polypropylene resins, tetrafluoroethylene resins, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, tetrafluoroethylene-hexafluoropropylene copolymer resins, tetrafluoroethylene-ethylene copolymer resins, chlorotrifluoroethylene-ethylene copolymer resins, vinylidene fluoride resins, chlorotrifluoroethylene copolymer resins, and vinyl fluoride resins. Of these, fluorine-based resins are preferably used in order to prevent contamination.

Specific examples of the container whose inner wall is formed of a fluorine-based resin include FluoroPure PFA composite drums manufactured by Entegris. Containers described in page 4 etc. of JP1991-502677A (JPH03-502677A), page 3 etc. of WO2004/016526A, and pages 9 and 16 etc. of WO99/046309A can also be used.

When the inner wall is formed of a nonmetallic material, it is preferable that the elution of an organic component in the nonmetallic material into the liquid is suppressed.

The liquid-contacting portions may be formed of a metal material.

No particular limitation is imposed on the metal material. A metal material containing chromium in an amount of more than 25% by mass based on the total mass of the metal material is preferred. Examples of the metal material include stainless steel and nickel-chromium alloys, and stainless steel is preferred.

No particular limitation is imposed on the stainless steel, and any well-known stainless steel can be used. In particular, an alloy containing nickel in an amount of 8% by mass or more is preferred, and austenitic stainless steel containing nickel in an amount of 8% by mass or more is more preferred. Examples of the austenitic stainless steel include SUS (Steel Use Stainless) 304 (Ni content: 8% by mass, Cr content: 18% by mass), SUS 304L (Ni content: 9% by mass, Cr content: 18% by mass), SUS 316 (Ni content: 10% by mass, Cr content: 16% by mass), and SUS 316L (Ni content: 12% by mass, Cr content: 16% by mass).

No particular limitation is imposed on the nickel-chromium alloy, and any well-known nickel-chromium alloy can be used. Examples of the nickel-chromium alloy include Hastelloy (trade name, the same applies to the following), Monel (trade name, the same applies to the following), and Inconel (trade name, the same applies to the following). More specific examples include Hastelloy C-276 (Ni content: 63% by mass, Cr content: 16% by mass), Hastelloy-C(Ni content: 60% by mass, Cr content: 17% by mass), and Hastelloy C-22 (Ni content: 61% by mass, Cr content: 22% by mass).

The nickel-chromium alloy may optionally further contain, in addition to the alloying elements described above, silicon, tungsten, molybdenum, copper, cobalt, etc.

The above metal material may preferably have been electropolished and is more preferably electropolished stainless steel.

Any well-known electropolishing method can be used, and examples thereof include methods described in [0011] to [0014] of JP2015-227501A and in [0036] to [0042] of JP2008-264929A.

The metal material may have been buffed for the purpose of preventing contamination. No particular limitation is imposed on the buffing method, and any well-known method can be used. No particular limitation is imposed on the size of abrasive grains used for finish buffing. The abrasive grain size is preferably less than or equal to #400 because irregularities on the surface of the metal material can be more easily reduced. Preferably, the buffing is performed before electropolishing.

The metal material may have been subjected to one of or a combination of two or more of the following processes: buffing including a plurality of stages performed using different abrasive grains with different sizes, washing with acid, and magnetic fluid grinding.

Preferably, the inside of the container has been washed before the container is filled with the treatment liquid. The liquid used for the washing is preferably the treatment liquid described above or a solution obtained by diluting the treatment liquid.

The treatment liquid of the invention can be used for the following pattern forming method.

The pattern forming method includes: step 1 of forming a metal resist film on a substrate using an actinic ray-sensitive or radiation-sensitive composition (which is hereinafter referred to also as a “metal resist composition”) containing a metal compound having at least one bond selected from the group consisting of a metal-carbon bond and a metal-oxygen bond (this metal compound is hereinafter referred to also as a “specific metal compound”); step 2 of exposing the metal resist film to light; and step 3 of subjecting the light-exposed metal resist film to developing treatment using a developer to remove unexposed portions to thereby obtain a pattern. The pattern forming method may further include, after step 3, step 4 of washing the pattern using a rinsing liquid.

Each of the steps will be described in detail.

Step 1 is the step of forming the metal resist film using the metal resist composition.

Examples of the method for forming the metal resist film using the metal resist composition include a method in which the metal resist composition is applied to a substrate and a method in which the metal resist composition is vapor-deposited on a substrate. The metal resist composition will be described later.

Examples of the method in which the metal resist composition is applied to a substrate include a method in which the metal resist composition is applied to a substrate (such as a silicon substrate) used to produce semiconductor devices such as integrated circuits using a device such as a spinner or a coater.

The coating method is preferably spin coating using a spinner. The rotation speed during spin coating is preferably 1000 to 3000 rpm.

The metal resist film may be formed by drying the substrate coated with the metal resist composition.

Examples of the drying method include heating (pre-baking). Means included with a well-known exposing device and/or a well-known developing device can be used for the heating, and a hot plate may be used.

The heating temperature is preferably 80 to 150° C., more preferably 80 to 140° C., and still more preferably 80 to 130° C. The heating time is preferably 30 to 1000 seconds, more preferably 30 to 800 seconds, and still more preferably 40 to 600 seconds. The heating may be repeated two or more times.

The thickness of the metal resist film is preferably 10 to 90 nm, more preferably 10 to 65 nm, and still more preferably 15 to 50 nm because a more precise and finer pattern can be formed.

An undercoat film (such as an inorganic film, an organic film, or an antireflection film) may be formed between the substrate and the metal resist film. The undercoat film can be formed using a well-known organic or inorganic material. Examples of a composition for forming the undercoat film include AL412 (manufactured by Brewer Science) and the SHB series (such as SHB-A940 manufactured by Shin-Etsu Chemical Co., Ltd.).

The thickness of the undercoat film is preferably 10 to 90 nm, more preferably 10 to 50 nm, and still more preferably 10 to 30 nm.

A topcoat may be formed on a surface of the metal resist film that is opposite from the substrate using a topcoat composition.

Preferably, the topcoat composition does not mix with the metal resist film and can be applied uniformly to the surface of the metal resist film that is opposite from the substrate.

Preferably, the topcoat composition contains a resin, an additive, and a solvent.

The method for forming the topcoat may be, for example, any well-known topcoat forming method, and specific examples include a topcoat forming method described in [0072] to [0082] of JP2014-059543A.

The metal resist composition contains the specific metal compound.

The specific metal compound is a metal compound having at least one bond selected from the group consisting of a metal-carbon bond (M-C) and a metal-oxygen bond (M-O). M represents a metal.

The metal-carbon bond is a state in which a metal atom and at least one carbon atom are bonded through a covalent bond, a coordinate bond, an ionic bond, a van der Waals bond, etc. The covalent bond may be a single bond, a double bond, or a triple bond. The metal-oxygen bond is a state in which at least one metal atom and at least one oxygen atom in the specific metal compound are bonded through a covalent bond, a coordinate bond, an ionic bond, a van der Waals bond, etc. The covalent bond may be a single bond or a double bond.

When the specific metal compound has a metal-carbon bond, the specific metal compound is a so-called organometallic compound.

The number of bonds in the specific metal compound that are selected from the above group is preferably 2 or more and more preferably 3 or more. The upper limit of the number of bonds is preferably 10 or less and more preferably 5 or less.

Examples of the metal atom included in the specific metal compound include group 3 to group 15 metal atoms in the periodic table, and the metal atom is preferably tin, antimony, tellurium, indium, hafnium, tantalum, tungsten, bismuth, titanium, cobalt, nickel, zirconium, or palladium and is more preferably tin.

In the present specification, silicon atoms are classified as metal atoms.

Examples of the specific metal compound include a compound represented by formula (1).

In formula (1), M represents a metal atom.

M is a metal atom included in the specific metal compound. The metal atom is preferably tin, antimony, tellurium, indium, hafnium, tantalum, tungsten, bismuth, titanium, cobalt, nickel, zirconium, or palladium and is more preferably tin.

In formula (1), R1 represents an alkyl group optionally having a substituent, an unsaturated aliphatic hydrocarbon group optionally having a substituent, or an aryl group optionally having a substituent.

The alkyl group may be linear, branched, or cyclic.

The number of carbon atoms in the alkyl group is preferably 1 to 30, more preferably 1 to 16, and still more preferably 1 to 5. When the alkyl group represented by R1 is an alkyl group having a substituent, the number of carbon atoms includes the number of carbon atoms in the substituent.

Examples of the optional substituent in the alkyl group include a halogen atom, a hydroxy group, a cyano group, a nitro group, an amino group, and aromatic ring groups. The aromatic ring group is preferably a phenyl group. The alkyl group having a phenyl group is preferably a benzyl group.

The unsaturated aliphatic hydrocarbon group is an aliphatic hydrocarbon group having an unsaturated group. Examples of the unsaturated group include a double bond and a triple bond.

The unsaturated aliphatic hydrocarbon group may be linear, branched, or cyclic.

The number of carbon atoms in the unsaturated aliphatic hydrocarbon group is preferably 2 to 30, more preferably 2 to 16, and still more preferably 2 to 5. When the unsaturated aliphatic hydrocarbon group represented by R1 is an unsaturated aliphatic hydrocarbon group having a substituent, the number of carbon atoms includes the number of carbon atoms in the substituent.

The unsaturated aliphatic hydrocarbon group is preferably a vinyl group or an allyl group.

Examples of the optional substituent in the unsaturated aliphatic hydrocarbon group include halogen atoms, a hydroxy group, a cyano group, a nitro group, an amino group, and aromatic ring groups.

The aryl group may be monocyclic or may be polycyclic.

The number of carbon atoms in the aryl group is preferably 6 to 30, more preferably 6 to 12, and still more preferably 6 to 8. When the aryl group represented by R1 is an aryl group having a substituent, the number of carbon atoms includes the number of carbon atoms in the substituent.

The aryl group is preferably a phenyl group or a naphthyl group.

Examples of the optional substituent in the aryl group include alkyl groups, halogen atoms, a hydroxy group, a cyano group, a nitro group, an amino group, and aromatic ring groups.

In formula (1), R2 represents —OCORr1 or —ORr2. Rr1 represents a hydrogen atom, an alkyl group optionally having a substituent, an unsaturated aliphatic hydrocarbon group optionally having a substituent, or an aryl group optionally having a substituent. Rr2 represents an alkyl group optionally having a substituent, an unsaturated aliphatic hydrocarbon group optionally having a substituent, or an aryl group optionally having a substituent.

Examples of the alkyl group optionally having a substituent, the unsaturated aliphatic hydrocarbon group optionally having a substituent, and the aryl group optionally having a substituent that are represented by Rr1 or Rr2 include those of the groups represented by R1 described above.

In formula (1), n1+m1 represents the valence of the metal atom represented by M.

n1+m1 is appropriately selected according to the possible valence of the metal atom represented by M.

n1 is preferably an integer of 0 to 2 and more preferably 1.

m1 is preferably an integer of 0 to 4 and more preferably 3.

When a plurality of R1s are present, the R1s may be the same or different. When a plurality of R2s are present, the R2s may be the same or different.

Other examples of the specific metal compound include a compound represented by formula (2) and condensates thereof.

In formula (2), R3 represents a hydrocarbon group optionally having a substituent.

Examples of the hydrocarbon group include alkyl groups optionally having a substituent, unsaturated aliphatic hydrocarbon groups optionally having a substituent, and aryl groups optionally having a substituent. Preferred forms of the alkyl groups, the unsaturated aliphatic hydrocarbon groups, and the aryl groups are the same as the preferred forms of the groups represented by R1.

When a plurality of R3s are present, the R3s may be the same or different.

z and x are numbers that satisfy the relation of formula (2-1) and the relation of formula (2-2).

Other examples of the specific metal compound include a compound represented by formula (3).

In formula (3), M represents a metal atom.

Examples of M include those of the metal atom represented by M in formula (1).

R4 and R6 each independently represent an alkyl group optionally having a substituent, an unsaturated aliphatic hydrocarbon group optionally having a substituent, or an aryl group optionally having a substituent.

Examples of R4 and R6 include those of the group represented by R1 above.

R5 and R7 each independently represent —OCORr3 or —ORr4. Rr3 represents a hydrogen atom, an alkyl group optionally having a substituent, an unsaturated aliphatic hydrocarbon group optionally having a substituent, or an aryl group optionally having a substituent. Rr4 represents an alkyl group optionally having a substituent, an unsaturated aliphatic hydrocarbon group optionally having a substituent, or an aryl group optionally having a substituent.

Examples of Rr3 and Rr4 include those of the groups represented by Rr1 and Rr2.

Examples of R5 and R7 include those of the group represented by R2.

When a plurality of R4s are present, the R4s may be the same or different. When a plurality of R5s are present, the R5s may be the same or different. When a plurality of R6s are present, the R6s may be the same or different. When a plurality of R7s are present, the R7s may be the same or different.

L represents a single bond or a divalent linking group.

Examples of the divalent linking group include alkylene groups and arylene groups.

n2+m2 and n3+m3 each independently represent the valence of the metal atom represented by M-1.

Other examples of the specific metal compound include a compound represented by formula (4), hydrolysates thereof, and condensates of the hydrolysates.

In formula (4), R8 represents a hydrocarbon group optionally having a substituent.

Examples of the hydrocarbon group include those of the group represented by R1.

X represents a hydrolyzable group. nz represents 1 or 2.

Examples of X include —NHRx1, —NRx1Rx2, —OSiRx1Rx2Rx3, —N(SiRx1)(Rx2), —N(SiRx13)(SiRx23), an azido group, —C≡CRx1, —NH(CORx1), —NRx1(CORx2), —NRx1C(NRx2)Rx3 (an amidinate group), and an imido group, and —NHRx1 or —NRx1Rx2 is preferred. Rx1 to Rx3 each independently represent a hydrocarbon group having 1 to 10 carbon atoms. Rx1 to Rx3 are each preferably an alkyl group having 1 to 10 carbon atoms.

When a plurality of R8s are present, the R8s may be the same or different. When a plurality of Xs are present, the Xs may be the same or different.

The specific metal compound is preferably a compound represented by formula (5).

In formula (5), R9 represents an alkyl group optionally having a substituent, an unsaturated aliphatic hydrocarbon group optionally having a substituent, or an aryl group optionally having a substituent. R10 represents —OCORr5 or —ORr6. Rr5 represents a hydrogen atom, an alkyl group optionally having a substituent, an unsaturated aliphatic hydrocarbon group optionally having a substituent, or an aryl group optionally having a substituent. Rr6 represents an alkyl group optionally having a substituent, an unsaturated aliphatic hydrocarbon group optionally having a substituent, or an aryl group optionally having a substituent.

R9, R10, Rr5, and Rr6 are the same as R1, R2, Rr1, and Rr2, respectively, in formula (1), and their preferred forms are also the same as those of R1, R2, Rr1, and Rr2 in formula (1).

The plurality of R1s present may be the same or different.

The specific metal compound includes preferably at least one selected from the group consisting of the compound represented by formula (1), the compound represented by formula (2), and condensates thereof, includes more preferably at least one selected from the group consisting of the compound represented by formula (5), the compound represented by formula (2), and condensates thereof, and includes still more preferably at least one selected from the group consisting of the compound represented by formula (2) and condensates thereof.

Other examples of the specific metal compound include specific metal compounds described in JP2021-047426A, JP2021-179606A, JP6805244B, and WO2019/111727A.

One specific metal compound may be used alone, or a combination of two or more may be used.

The content of the specific metal compound is preferably 50 to 100% by mass and more preferably 80 to 100% by mass based on the total solid amount of the metal resist composition.

The metal resist composition may contain an organic acid.

Other examples of the organic acid that can be contained in the metal resist composition include those of the organic acid that can be contained in the treatment liquid.

One organic acid may be used alone, or a combination of two or more may be used.

The content of the organic acid is preferably 0 to 10% by mass and more preferably 1 to 5% by mass based on the total solid amount of the metal resist composition.

The metal resist composition may contain an organic solvent. Examples of the organic solvent include ketone-based solvents, ester-based solvents, alcohol-based solvents, amide-based solvents, ether-based solvents, and hydrocarbon-based solvents.

Examples of the ether-based solvent include dioxane, tetrahydrofuran, anisole, and diisobutyl ether. Of these, diisobutyl ether is preferred.

The metal resist composition may contain additional additives such as a surfactant, water, a dissolution inhibiting compound, a dye, a plasticizer, a photosensitizer, a light-absorbing agent, and a compound that increases solubility in the developer (e.g., a phenol compound having a molecular weight of 1000 or less or an alicyclic or aliphatic compound having a carboxylic acid group).

The surfactant is preferably a fluorine-based surfactant or a silicon-based surfactant. For example, surfactants described in paragraphs [0218] and [0219] of WO2018/193954A can be used.

Step 2 is the step of exposing the metal resist film to light. The entire metal resist film may be exposed to light, or the metal resist film may be exposed to light in a pattern.

Preferably, step 2 is the step of exposing the metal resist film to light in a pattern through a photomask.

The photomask is, for example, any well-known photomask. The photomask may be in contact with the metal resist film.

Examples of the light to which the metal resist film is exposed include infrared light, visible light, ultraviolet light, far-ultraviolet light, extreme ultraviolet (EUV) light, X rays, and electron beams.

The wavelength of the exposure light is preferably 250 nm or less, more preferably 220 nm or less, and still more preferably 1 to 200 nm. Specifically, the light is preferably KrF excimer laser light (wavelength: 248 nm), ArF excimer laser light (wavelength: 193 nm), F2 excimer laser light (wavelength: 157 nm), X rays, EUV light (wavelength: 13 nm), or an electron beam, more preferably KrF excimer laser light, ArF excimer laser light, EUV light, or an electron beam, and still more preferably EUV light or an electron beam.

No particular limitation is imposed on the amount of light exposure so long as the solubility of the metal resist film exposed to light in the developer containing the organic solvent decreases.

The light exposure method may be liquid immersion exposure.

Step 2 may be performed once or two or more times.

Step 3 is the step of subjecting the light-exposed metal resist film to developing treatment using a developer. In the developing treatment, unexposed portions of the light-exposed metal resist film are removed, and a pattern is thereby formed.

The developing method used may be any well-known developing method. Specific examples of the developing method include: a method (dipping method) in which the light-exposed metal resist film is immersed in a bath filled with the developer for a prescribed time; a method (puddle method) in which the developer is placed on the surface of the light-exposed metal resist film so as to form a convex puddle due to surface tension and left to stand for a prescribed time to develop the metal resist film; a method (spraying method) in which the developer is sprayed onto the surface of the light-exposed metal resist film; and a method (dynamic dispensing method) in which the developer is continuously dispensed onto a constantly rotating substrate with the light-exposed metal resist film disposed thereon while a nozzle from which the developer is discharged is moved.

After the developing step, the step of terminating the development using a solvent other than the developer may be performed.

The developing time is preferably 10 to 300 seconds and more preferably 20 to 120 seconds.

The temperature of the developer during development is preferably 0 to 50° C. and more preferably 15 to 35° C.

The treatment liquid of the invention can be used as the developer in step 3.

When the pattern forming method does not include step 4 described later or when the pattern forming method includes step 4 described later and the rinsing liquid in step 4 is an additional chemical solution different from the treatment liquid, the developer in step 3 is preferably the treatment liquid of the invention described above.

When the pattern forming method includes step 4 described later and the rinsing liquid in step 4 is the treatment liquid of the invention, the developer in step 3 may be the treatment liquid of the invention described above or may be an additional chemical solution different from the treatment liquid of the invention.

The additional chemical solution used differs from the treatment liquid of the invention described above and can be any well-known developer or any well-known rinsing liquid.

The additional chemical solution contains an organic solvent. Examples of the organic solvent contained in the additional chemical solution include ketone-based solvents, ester-based solvents, alcohol-based solvents, amide-based solvents, ether-based solvents, and hydrocarbon-based solvents. Specific examples include organic solvents that can be contained in the metal resist.

The additional chemical solution may contain one organic solvent alone or may contain a combination of two or more organic solvents.

The additional chemical solution may contain an organic solvent different from those described above, water, a surfactant, etc.

Step 4 is the step of washing the pattern obtained in step 3 (developing step) with a rinsing liquid.

Examples of the rinsing method are the same as those of the developing method in step 3 (such as the dipping method, the puddle method, the spraying method, and the dynamic dispensing method).

The treatment time is preferably 10 to 300 seconds and more preferably 10 to 120 seconds.

The temperature of the rinsing liquid is preferably 0 to 50° C. and more preferably 15 to 35° C.

When the developer in step 3 is the additional chemical solution, it is preferable that the rinsing liquid in step 4 is the treatment liquid of the invention described above.

When the developer in step 3 is the treatment liquid of the invention described above, the rinsing liquid in step 4 may be the treatment liquid of the invention described above or may be the additional chemical solution.

Examples of the additional chemical solution that can be used as the rinsing liquid are the same as those of the chemical solution that can be used as the developer, and preferred forms of the additional chemical solution are also the same as those of the chemical solution that can be used as the developer.

The pattern forming method may further include additional steps other than steps 1 to 4.

Examples of the additional steps include a post-exposure baking step, a post-baking step, an etching step, and a purification step.

Preferably, the pattern forming method includes, after step 2 (the light exposure step) but before step 3 (the developing step), a post-exposure baking (PEB) step.

The heating temperature for the post-exposure baking is preferably 80 to 200° C., more preferably 80 to 180° C., and still more preferably 80 to 150° C. The heating time is preferably 10 to 1000 seconds, more preferably 10 to 180 seconds, and still more preferably 30 to 120 seconds.

The post-exposure baking may be performed using means included with a well-known exposing device and/or a well-known developing device and a hot plate. The post-exposure baking may be performed once or two or more times.

Preferably, the pattern forming method includes, after step 4 (the rinsing step), the step of heating the pattern (the post-baking step). With the post-baking (PB) step, the developer and the rinsing liquid remaining between traces of the pattern and inside the pattern can be removed, and the surface roughness of the pattern can be improved.

The heating temperature in the post-baking step is preferably 40 to 250° C. and more preferably 80 to 200° C.

The heating time in the post-baking step is preferably 10 to 180 seconds and more preferably 30 to 120 seconds.

The pattern forming method may include the etching step of etching the substrate using the formed pattern as a mask.

The etching method used may be any well-known etching method. Specific examples include a method described in Proceedings of Society of Photo-Optical Instrumentation Engineers (Proc. Of SPIE) Vol. 6924, 692420 (2008), a method described in “Chapter 4 Etching” in “Semiconductor Process Text Book, 4th Ed., published in 2007, publisher: SEMI Japan,” and a method described in JP2009-267112A.

The pattern forming method may include the purification step of purifying the metal resist composition, the developer, the rinsing liquid, and/or other various components (such as the composition for forming the undercoat film and the composition for forming the topcoat) used for the pattern forming method.

The purification method is, for example, a well-known purification method and is preferably filtering or a method using an adsorbent.

[Method for Producing Electronic Device]

The electronic device production method of the invention includes the step of using the treatment liquid of the invention described above. A preferred form of the invention is an electronic device production method including the step of forming a pattern using the treatment liquid of the invention according to the pattern forming method described above.

The electronic device is suitably installed in electric and electronic devices (such as household electrical appliances, OA (Office Automation) devices, media-related devices, optical devices, and communication devices).

EXAMPLES

The present invention will be further described in detail by way of Examples.

Materials, amounts used, ratios, treatment details, treatment procedures, etc. shown in the following Examples can be appropriately changed so long as they do not depart from the gist of the invention. Therefore, the scope of the present invention should not be construed as limited to the following Examples.

[Preparation of Treatment Liquids]

[Preparation of Raw Materials]

PGMEA, PGME, and organic acids were synthesized and/or purified according to the following procedures.

<Synthesis and Purification of PGME>

An unpurified product containing PGME was synthesized using a method described in JP2011-509998A.

Next, the obtained unpurified product was subjected to circulating filtration purification using a filtration device including the following ion exchange resin and filters connected in series from the upstream side and further including a return passage extending from the most downstream side to the most upstream side. The number of circulation cycles was 50.

The details of the members in the filtration device are shown below in the order from the upstream side.

In the circulating filtration purification, the operation in which the unpurified product is caused to pass from the most upstream purification member to the most downstream purification member is counted as one circulation cycle.

A distillation column in which a first plate distillation column (the theoretical number of plates: 150) including no pressure reduction mechanism and a second plate distillation column (the theoretical number of plates: 150) including a pressure reduction mechanism were connected in series was used to perform distillation purification sequentially from the first plate distillation column to thereby obtain PGME used as a raw material of treatment liquids.

A filtration device including the following filters connected in series from the upstream side and further including a return passage extending from the most downstream side to the most upstream side was used to subject organic acids independently to circulating filtration purification. The organic acids used were acetic acid (manufactured by KANTO CHEMICAL Co.), formic acid (manufactured by KANTO CHEMICAL Co., Inc.), propionic acid (manufactured by Sigma-Aldrich), butyric acid (manufactured by Sigma-Aldrich), and lactic acid (manufactured by Sigma-Aldrich). The number of circulation cycles was 50.

The details of the members in the filtration device are shown below in the order from the upstream side.

Then distillation purification was performed using the same method as that for the distillation purification of PGME.

The PGME synthesized and circulating-filtration-purified by the method described above and the acetic acid circulating-filtration-purified by the method described above were used as raw materials to synthesize an unpurified product containing PGMEA by ester synthesis.

The ester synthesis was performed using a method described in JP2001-521918A.

The obtained unpurified product was subjected to dewatering treatment by a column method using a molecular sieve 3A (manufactured by FUJIFILM Wako Pure Chemical Corporation).

Next, distillation purification was performed by the same method as that for the distillation purification of PGME.

A filtration device including the following filters connected in series from the upstream side and further including a return passage extending from the most downstream side to the most upstream side was used to perform circulating filtration purification, and PGMEA used as a raw material of the treatment liquids was thereby obtained. The number of circulation cycles was 50.

The details of the members in the filtration device are shown below in the order from the upstream side.

In the manner described above, PGMEA, PGME, and acetic acid were obtained in which the water content was reduced to the detection limit or lower and the boron atom content and the Pb atom content were less than 0.0001 ppt by mass.

The water content was measured using the above-described Karl Fischer moisture meter (product name: “MKC-710M” manufactured by Kyoto Electronics Manufacturing Co., Ltd., Karl Fischer coulometric titration type). The limit of detection of water by this device was 1 ppm by mass.

The boron atom content was measured using the above-described ICP-MS (device used: Agilent 8900 triple quadrupole ICP-MS). The limit of detection of the boron atom content by this device was 0.6 ppt by mass (unconcentrated).

The Pb atom content was measured using the above-described ICP-MS (device used: Agilent 8900 triple quadrupole ICP-MS). The limit of detection of the Pb atom content by this device was 0.1 ppt by mass (unconcentrated).

The PGMEA, PGME, and acetic acid were concentrated in the same manner as in the measurement method for the treatment liquid described later, and then the boron atom content and the Pb atom content in each of the PGMEA, PGME, and acetic acid were measured using the device described above. The boron atom content was found to be 0.0001 ppt by mass or less, and the Pb atom content was found to be 0.0001 ppt by mass or less.

For each of the above-obtained PGMEA, PGME, and acetic acid concentrated in the same manner as in the measurement method for the treatment liquid described later and then used for the measurement of Pb atoms using the device described above, the contents of transition elements other than Pb atoms and measurable by ICP-MS were all less than 0.0001 ppt by mass.

The PGME obtained by the method described above, one of the organic acids obtained by the method described above, ultrapure water, a boron atom source, and a Pb atom source were added all at once or in portions to the PGMEA obtained by the method described above such that a composition shown in one of the following tables was obtained, and a treatment liquid in one of Examples and Comparative Examples was thereby prepared.

The boron atom content, the Pb content, and the total content of transition metals other than Pb in the ultrapure water used to prepare the treatment liquids were found to be the same as their contents in the PGMEA etc. described above.

The boron atom source was added by the following method. Solid high-purity boron (manufactured by Tokuyama Corporation) was immersed in a treatment liquid for a prescribed time to allow boron to dissolve in the treatment liquid such that the boron atom content was adjusted to a prescribed value.

The amount of high-purity boron immersed in the treatment liquid and the immersion time were set as follows. A calibration curve for the dissolution amount of boron atoms in relation to the surface area of the high-purity boron and the immersion time was produced, and the amount of immersed high-purity boron and the immersion time were set such that the final boron atom content in the treatment liquid was adjusted to a prescribed value. The boron atom content in each treatment liquid was measured by ICP-MS using an Agilent 8900 triple quadrupole ICP-MS (manufactured by Agilent Technologies, semiconductor analysis use, option: #200).

When the content of boron atoms (boron) in a treatment liquid was quantified, the following procedure was used.

First, ultrapure water (standard product) was added to the treatment liquid to be subjected to quantification of boron atoms in an amount of 0.001% by mass based on the total mass of the treatment liquid. In the ultrapure water added, the boron atom content was 0.0001 ppt by mass based on the total mass of the ultrapure water added. To determine the boron atom content in the ultrapure water, the ultrapure water was concentrated by a factor of 10000, and then the measurement was performed using the same method as described above. As described above, it is expected from the potential-pH diagram for the water-boron system that boron is present in the form of boric acid in the ultrapure water.

Next, the treatment liquid with the ultrapure water added thereto was heated at 100° C. for 1 hour under reflux conditions to convert boron present in the treatment liquid to the form of boric acid. Then the organic solvents and water contained in the treatment liquid were removed at 160 to 180° C. to concentrate the non-volatile components contained in the treatment liquid, and the boron atom content was quantified using the device described above. The content of boron atoms contained in the treatment liquid was computed in consideration of the mass of the boron atoms contained in the ultrapure water.

When the non-volatile components were concentrated, the contents of boron atoms in different treatment liquids with concentration factors ranging from 10 to 1000 were computed. Then positive correlation was found between the concentration factor and the boron atom content, and the coefficient of determination (R2) in linear regression was more than 0.98. Specifically, by concentrating a treatment liquid using the method described above, the content of boron atoms contained in the treatment liquid could be quantified.

To add the Pb atom source, a PGMEA solution of Pb nanoparticles ((5N) 99.999% Lead Oxide Nanopowder manufactured by American Elements) with the concentration adjusted to a prescribe value was added to the treatment liquid.

[Preparation of Metal Resist Composition]

Monobutyltin oxide hydrate (BuSnOOH) powder (0.209 g, TCI America) was added to 4-methyl-2-pentanol (10 mL) to prepare a metal resist precursor solution. The solution was placed in a closed vial and stirred for 24 hours. The resulting mixture was subjected to centrifugation at 4000 rpm for 15 minutes and filtrated using a 0.45 μm PTFE syringe filter to remove insoluble materials, and a metal resist composition was thereby obtained.

The organic solvent in the metal resist composition was removed, and the resulting metal resist composition was fired at 600° C. The content of Sn determined from the remaining mass of SnO2 was 0.093M.

The metal resist precursor solution was subjected to DLS (Dynamic Light Scattering) analysis using a Moebius device (manufactured by Wyatt Technology). The results were consistent with a unimodal distribution of particles having an average particle diameter of 2 nm and also consistent with the reported diameter of dodecameric butyltin hydroxide oxide polyatomic cations (Eychenne-Baron et al., Organometallics, 19, 1940-1949 (2000)).

An undercoat film-forming composition SHB-A940 (manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to a silicon wafer having a diameter of 300 mm and baked at 205° C. for 60 seconds to form an undercoat film having a thickness of 20 nm. The metal resist composition was applied to the obtained undercoat film and baked at 100° C. for 90 seconds to form a metal resist film having a thickness of 22 nm. The silicon wafer having the metal resist film was thereby formed.

The silicon water having the metal resist film was subjected to pattern light exposure using an EUV scanner NXE3400 (manufactured by ASML, NA: 0.33) at a minimum light exposure at a resolution limit described later. The reticle used was a pillar pattern with a pitch of 45 nm and an opening size of 25 nm. Then post-exposure baking (PEB) was performed at 150° C. for 90 seconds.

Next, in Examples 1 to 131 and Comparative Examples 1 to 44, the treatment liquid in one of the Examples and Comparative Examples was used to perform puddle development treatment for 30 seconds, and then the wafter was rotated at 4000 rpm for 30 seconds to dry the wafter. A pillar pattern with a pitch of 45 nm was thereby obtained.

In Examples 132 to 138 and Comparative Examples 45 to 48, the developer in Comparative Example 3 was used to perform puddle development treatment for 30 seconds. Next, while the wafer was rotated at 1000 rpm, one of the treatment liquids in the Examples and Comparative Examples was poured for 10 seconds to perform rinsing treatment. Then the wafer was rotated at 4000 rpm for 30 seconds to dry the wafer, and a pillar pattern with a pitch of 45 nm was thereby obtained.

The same procedure as that in the [Formation of pillar pattern] section described above was repeated except that a line-and-space pattern with a line width of 20 nm and a space of 20 nm was used as the reticle to thereby obtain a line-and-space pattern with a line width of 20 nm and a space of 20 nm.

[Ability to Suppress Occurrence of Pattern Defects]

A scanning electron microscope (S-938011 manufactured by Hitachi, Ltd.) was used to observe each line-and-space pattern in 100 viewing fields (magnification: 100k×) to check the number of defects in the pattern. The ability to suppress the occurrence of pattern defects was evaluated from the obtained number of pattern defects according to the following evaluation criteria.

The smaller the number of pattern defects, the better.

A silicon substrate with a diameter of 300 mm was prepared, and a surface defect inspection system (SurfScan SP7 manufactured by KLA) was used to irradiate the surface of the silicon substrate with laser light, and the scattered light was measured to determine the positions of defects on the silicon substrate and their sizes.

One of the treatment liquids in the Examples and Comparative Examples was applied to the silicon substrate using a coater/developer (CLEAN TRACK LITHIUS PRO Z manufactured by Tokyo Electron Ltd.). Then the silicon substrate was spin-dried at 2000 rpm for 30 seconds, and the surface defect inspection system (SurfScan SP7 manufactured by KLA) was used to determine the positions of defects on the silicon substrate and their sizes using the method described above.

Defects originating from the treatment liquid were extracted based on the positions of the defects, the numbers of defects, and the sizes of the defects before and after the application of the treatment liquid, and the ability to suppress the occurrence of defects originating from the treatment liquid was evaluated according to the following evaluation criteria.

The smaller the number of defects originating from the treatment liquid, the better.

A critical dimension scanning electron microscope (CG6300 manufactured by Hitachi High-Tech Corporation) was used to observe 2000 pillars for each of different light exposure amounts, and the average pillar diameters and the quality of the patterns were checked. The average pillar diameter at the minimum light exposure amount at which the number of collapsed pillars among the 2000 observed pillars was zero was defined as a critical resolution, and the resolution was evaluated according to the following evaluation criteria.

The smaller the critical resolution, the higher the resolution, and the better.

Each of the treatment liquids in the Examples and Comparative Examples was held at a high temperature (85° C.) for 1 hour and then held at a low temperature (5° C.) for 1 hour. This procedure was defined as one cycle (the heating/cooling rate was 5° C./minute). While this cycle was repeated, the treatment liquid was stored for one month under cyclic heating and cooling. The resulting treatment liquid was used to evaluate the defects originating from the treatment liquid after storage under cyclic heating and cooling using the same method as that for the evaluation of the [Ability to suppress occurrence of defects originating from treatment liquid] described above.

The numbers of defects of 20 nm or less originating from the treatment liquid before and after storage under cyclic heating and cooling were compared, and the resistance to deterioration of the ability to suppress the occurrence of defects originating from the treatment liquid due to storage under cyclic heating and cooling was evaluated according to the following evaluation criteria.

The smaller the increase in the number of defects before and after storage under cyclic heating and cooling, the smaller the degree of deterioration of the treatment liquid during storage, and the better.

Each of the treatment liquids in the Examples and Comparative Examples was held at a high temperature (85° C.) for 1 hour and then held at a low temperature (5° C.) for 1 hour. This procedure was defined as one cycle (the heating/cooling rate was 5° C./minute). While this cycle was repeated, the treatment liquid was stored for one month under cyclic heating and cooling. The resulting treatment liquid was used to compute the critical resolution using the same method as that for the evaluation of the [Pattern resolution] described above.

The critical resolutions before and after storage under cyclic heating and cooling were compared to evaluate the resistance to deterioration of the resolution performance of the treatment liquid due to storage under cyclic heating and cooling according to the following evaluation criteria.

The smaller the increase in the critical resolution before and after storage at high temperature, the smaller the degree of deterioration of the treatment liquid during storage, and the better.

The defects originating from the treatment liquid and detected in the evaluation of the [Ability to suppress occurrence of defects originating from treatment liquid] described above were subjected to qualitative elemental analysis using a defect review system (SEMVision G7E manufactured by Applied Materials).

The qualitative elemental analysis was performed using an SEM-EDS (Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy) installed in the defect review system.

The number of defects containing alkali metal elements or alkaline-earth metals (hereinafter referred to as “specific elements”) (these defects are hereinafter referred to as “specific element-containing defects”) was computed from the EDS spectrum obtained by the qualitative elemental analysis and evaluated according to the following evaluation criteria.

The smaller the number of specific element-containing defects, the better.

The number of defects containing elemental boron (boron-containing defects) was computed according to the evaluation procedure in the [Defects originating from alkali metals and/or alkaline-earth metals] section described above and evaluated according to the following evaluation criteria.

The smaller the number of boron-containing defects, the better.

Results

The compositions of the treatment liquids in the Examples and Comparative Examples, the applications of the treatment liquids, and the evaluation results are shown in Tables 1 to 8.

In the tables, the “Application” column indicates whether the treatment liquid was used as a developer or a rinsing liquid.

In the tables, the definition of “Organic acid/water” (specific mass ratio) is as described above.

In the tables, the “Ability to suppress occurrence of pattern defects” column indicates the results of evaluation of the ability to suppress the occurrence of pattern defects, and the “Ability to suppress occurrence of defects originating from treatment liquid)” column indicates the results of evaluation of the ability to suppress the occurrence of defects originating from the treatment liquid.

In the tables, the “Pattern resolution” column indicates the pattern resolution.

In the tables, the “Specific element-containing defects” column indicates the results of evaluation of the [Defects originating from alkali metals and/or alkaline-earth metals], and the “Boron-containing defects” column indicates the results of evaluation of the [Defects originating from boron atoms].

In each of the tables, the “Balance” in the “PGMEA” column means that the remaining portion other than the organic acid, PGME, water, boron, and Pb in the table is PGMEA. In each Example, the content of PGMEA was 60% by mass or more based on the total mass of the treatment liquid.

Treatment liquid

PGMEA
Organic acid
PGME
Water
Organic
Boron atom
Pb

Content

Content
Content
Content
acid/
Content
Content

Evaluation

After storage under cyclic

heating and cooling

Ability to suppress

Ability to suppress

Specific

Table 2
Ability to suppress
occurrence of defects

occurrence of defects

(continued
occurrence of
originating from
Pattern
originating from
Pattern
containing
containing

from Table 1)
patter defects
treatment liquid
resolution
treatment liquid
resolution
defects
defects

Example 1
A
A
A
A
A
A
A

Example 2
A
A
A
A
A
A
A

Example 3
A
A
B
A
A
A
A

Example 4
A
A
C
B
A
A
A

Example 5
A
A
C
B
A
A
A

Example 6
A
A
C
A
C
A
A

Example 7
A
A
A
A
A
A
A

Example 8
B
A
A
A
A
A
A

Example 9
C
A
A
A
A
A
A

Example 10
A
A
A
B
A
A
A

Example 11
A
A
C
C
A
A
A

Example 12
C
A
C
A
C
A
A

Example 13
A
A
A
A
A
A
A

Example 14
A
A
A
A
A
A
B

Example 15
A
A
A
A
A
A
C

Example 16
A
A
A
A
A
A
A

Example 17
A
A
A
A
A
A
A

Example 18
A
A
A
A
A
A
A

Example 19
A
A
A
A
A
A
A

Example 20
A
A
A
A
A
A
A

Example 21
A
A
A
A
A
A
A

Example 22
A
A
A
A
A
A
A

Example 23
A
A
A
A
A
A
A

Example 24
A
A
A
A
A
A
A

Example 25
A
D
A
A
A
A
A

Example 26
A
D
A
A
A
A
A

Example 27
A
A
A
A
A
A
A

Example 28
A
A
A
A
A
A
A

Example 29
A
A
B
A
A
A
A

Example 30
A
A
C
B
A
A
A

Example 31
A
A
C
B
A
A
A

Example 32
A
A
C
A
C
A
A

Example 33
A
A
A
A
A
A
A

Example 34
A
A
A
A
A
A
A

Example 35
C
A
A
A
A
A
A

Example 36
A
A
A
B
A
A
A

Example 37
A
A
C
C
A
A
A

Example 38
C
A
C
A
C
A
A

Example 39
A
A
A
A
A
A
A

Example 40
A
A
A
A
A
A
B

Example 41
A
A
A
A
A
A
C

Example 42
A
A
A
A
A
A
A

Example 43
A
A
A
A
A
A
A

Example 44
A
A
A
A
A
A
A

Example 45
A
A
A
A
A
A
A

Example 46
A
A
A
A
A
A
A

Example 47
A
A
A
A
A
A
A

Treatment liquid

PGMEA
Organic acid
PGME
Water
Organic
Boron atom
Pb

Content

Content
Content
Content
acid/
Content
Content

Table 3
[% by mass
Type
[% by mass]
[% by mass]
% by mass
water
[ppt by mass]
[ppt by mass]
Application

Evaluation

After storage under cyclic

heating and cooling

Ability to suppress

Ability to suppress

Specific

Table 4
Ability to suppress
occurrence of defects

occurrence of defects

(continued
occurrence of
originating from
Pattern
originating from
Pattern
containing
containing

from Table 3)
pattern defects
treatment liquid
resolution
treatment liquid
resolution
defects
defects

Example 48
A
A
A
A
A
A
A

Example 49
A
A
A
A
A
A
A

Example 50
A
A
A
A
A
A
A

Example 51
A
D
A
A
A
A
A

Example 52
A
D
A
A
A
A
A

Example 53
A
A
A
A
A
A
A

Example 54
A
A
A
A
A
A
A

Example 55
A
A
B
A
A
A
A

Example 56
A
A
C
B
A
A
A

Example 57
A
A
C
B
A
A
A

Example 58
A
A
C
A
C
A
A

Example 59
A
A
A
A
A
A
A

Example 60
A
A
A
A
A
A
A

Example 61
B
A
A
A
A
A
A

Example 62
A
A
A
B
A
A
A

Example 63
A
A
C
C
A
A
A

Example 64
B
A
C
A
C
A
A

Example 65
A
A
A
A
A
A
A

Example 66
A
A
A
A
A
A
B

Example 67
A
A
A
A
A
A
C

Example 68
A
A
A
A
A
A
A

Example 69
A
A
A
A
A
A
A

Example 70
A
A
A
A
A
A
A

Example 71
A
A
A
A
A
A
A

Example 72
A
A
A
A
A
A
A

Example 73
A
A
A
A
A
A
A

Example 74
A
A
A
A
A
A
A

Example 75
A
A
A
A
A
A
A

Example 76
A
A
A
A
A
A
A

Example 77
A
D
A
A
A
A
A

Example 78
A
D
A
A
A
A
A

Example 79
A
A
A
A
A
A
A

Example 80
A
A
A
A
A
A
A

Example 81
A
A
B
A
A
A
A

Example 82
A
A
C
B
A
A
A

Example 83
A
A
C
B
A
A
A

Example 84
A
A
C
A
C
A
A

Example 85
A
A
A
A
A
A
A

Example 86
B
A
A
A
A
A
A

Example 87
B
A
A
A
A
A
A

Example 88
C
A
A
C
A
A
A

Example 89
A
A
A
B
A
A
A

Example 90
A
A
C
C
A
A
A

Example 91
B
A
C
A
C
A
A

Example 92
A
A
A
A
A
A
A

Example 93
A
A
A
A
A
A
B

Example 94
A
A
A
A
A
A
C

Example 95
A
A
A
A
A
A
A

Example 96
A
A
A
A
A
A
A

Treatment liquid

PGMEA
Organic acid
PGME
Water
Organic
Boron atom
Pb

Content

Content
Content
Content
acid/
Content
Content

Evaluation

After storage under cyclic

heating and cooling

Ability to suppress

Ability to suppress

Specific

Table 6
Ability to suppress
occurrence of defects

occurrence of defects

(continued
occurrence of
originating from
Pattern
originating from
Pattern
containing
containing

from Table 5)
pattern defects
treatment liquid
resolution
treatment liquid
resolution
defects
defects

Example 97
A
A
A
A
A
A
A

Example 98
A
A
A
A
A
A
A

Example 99
A
A
A
A
A
A
A

Example 100
A
A
A
A
A
A
A

Example 101
A
A
A
A
A
A
A

Example 102
A
A
A
A
A
A
A

Example 103
A
A
A
A
A
A
A

Example 104
A
D
A
A
A
A
A

Example 105
A
D
A
A
A
A
A

Example 106
A
A
A
A
A
A
A

Example 107
A
A
A
A
A
A
A

Example 108
A
A
B
A
A
A
A

Example 109
A
A
C
B
A
A
A

Example 110
A
A
C
B
A
A
A

Example 111
A
A
C
A
C
A
A

Example 112
A
A
A
A
A
A
A

Example 113
A
A
A
A
A
A
A

Example 114
C
A
A
A
A
A
A

Example 115
A
A
A
B
A
A
A

Example 116
A
A
C
B
A
A
A

Example 117
C
A
C
A
C
A
A

Example 118
A
A
A
A
A
A
A

Example 119
A
A
A
A
A
A
B

Example 120
A
A
A
A
A
A
C

Example 121
A
A
A
A
A
A
A

Example 122
A
A
A
A
A
A
A

Example 123
A
A
A
A
A
A
A

Example 124
A
A
A
A
A
A
A

Example 125
A
A
A
A
A
A
A

Example 126
A
A
A
A
A
A
A

Example 127
A
A
A
A
A
A
A

Example 128
A
A
A
A
A
A
A

Example 129
A
A
A
A
A
A
A

Example 130
A
D
A
A
A
A
A

Example 131
A
D
A
A
A
A
A

Example 132
A
A
A
A
A
A
A

Example 133
A
A
A
A
A
A
A

Example 134
A
A
B
A
A
A
A

Example 135
A
A
C
B
A
A
A

Example 136
A
A
C
B
A
A
A

Example 137
A
A
C
A
C
A
A

Example 138
A
A
A
A
A
A
A

Treatment liquid

Boron atom
Pb

Content

Content
Content
Content
Organic
Content
Content

[% by

[% by
[% by
[% by
acid/
[ppt by
[ppt by

Table 7
mass
Type
mass]
mass
mass]
water
mass]
mass
Application

Evaluation

After storage under cyclic

heating and cooling

Ability to suppress

Ability to suppress

Specific

Table 8
Ability to suppress
occurrence of defects

occurrence of defects

(continued
occurrence of
originating from
Pattern
originating from
Pattern
containing
containing

from Table 7)
pattern defects
treatment liquid
resolution
treatment liquid
resolution
defects
defects

Comparative Example 1
A
A
D
B
A
A
A

Comparative Example 2
A
A
D
B
A
A
A

Comparative Example 3
A
A
D
A
D
A
A

Comparative Example 4
A
A
D
A
C
A
A

Comparative Example 5
D
A
A
A
A
A
A

Comparative Example 6
D
A
A
D
A
A
A

Comparative Example 7
C
A
A
D
A
A
A

Comparative Example 8
C
A
C
D
A
A
A

Comparative Example 9
D
A
C
A
D
A
A

Comparative Example 10
A
A
D
B
A
A
A

Comparative Example 11
A
A
D
B
A
A
A

Comparative Example 12
A
A
D
A
D
A
A

Comparative Example 13
A
A
D
A
C
A
A

Comparative Example 14
D
A
A
A
A
A
A

Comparative Example 15
D
A
A
D
A
A
A

Comparative Example 16
C
A
A
D
A
A
A

Comparative Example 17
C
A
C
D
A
A
A

Comparative Example 18
D
A
C
A
D
A
A

Comparative Example 19
A
A
D
B
A
A
A

Comparative Example 20
A
A
D
B
A
A
A

Comparative Example 21
A
A
D
A
D
A
A

Comparative Example 22
A
A
D
A
C
A
A

Comparative Example 23
D
A
A
A
A
A
A

Comparative Example 24
D
A
A
D
A
A
A

Comparative Example 25
C
A
A
D
A
A
A

Comparative Example 26
C
A
C
D
A
A
A

Comparative Example 27
D
A
C
A
C
A
A

Comparative Example 28
A
A
D
B
A
A
A

Comparative Example 29
A
A
D
B
A
A
A

Comparative Example 30
A
A
D
A
D
A
A

Comparative Example 31
A
A
D
A
C
A
A

Comparative Example 32
D
A
A
A
A
A
A

Comparative Example 33
D
A
A
D
A
A
A

Comparative Example 34
C
A
C
D
A
A
A

Comparative Example 35
D
A
C
A
D
A
A

Comparative Example 36
A
A
D
B
A
A
A

Comparative Example 37
A
A
D
B
A
A
A

Comparative Example 38
A
A
D
A
D
A
A

Comparative Example 39
A
A
D
A
C
A
A

Comparative Example 40
D
A
A
A
B
A
A

Comparative Example 41
D
A
A
D
A
A
A

Comparative Example 42
C
A
A
D
A
A
A

Comparative Example 43
C
A
C
D
A
A
A

Comparative Example 44
D
A
C
A
D
A
A

Comparative Example 45
A
A
D
B
A
A
A

Comparative Example 46
A
A
D
B
A
A
A

Comparative Example 47
A
A
D
A
D
A
A

Comparative Example 48
A
A
D
A
C
A
A

As can be seen from the results in Tables 1 to 8, the treatment liquids of the invention exhibit the desired effects.

Comparisons among Examples 1 to 7 etc. show that, when the content of the organic acid is 3.00 to 30.00% by mass based on the total mass of the treatment liquid, the pattern resolution is higher and that, when the content of the organic acid is 5.00 to 20.00% by mass, the pattern resolution is still higher.

Comparisons among Examples 1 and 8 to 10 etc. show that, when the content of water is 0.0003 to 0.008% by mass (3 to 80 ppm by mass) based on the total mass of the treatment liquid, the ability to suppress the occurrence of pattern defects is higher and that, when the content of water is 0.0005 to 0.005% by mass (5 to 50 ppm by mass), the ability to suppress the occurrence of pattern defects is still higher.

Comparisons among Examples 1 and 13 to 19 etc. show that, when the specific mass ratio is 500 to 50000, the deterioration of the ability to suppress the occurrence of defects originating from the treatment liquid after storage under cyclic heating and cooling and the deterioration of the pattern resolution after storage under cyclic heating and cooling can be further suppressed and that, when the specific mass ratio is 1000 to 10000, the deterioration of the ability to suppress the occurrence of defects originating from the treatment liquid after storage under cyclic heating and cooling and the deterioration of the pattern resolution after storage under cyclic heating and cooling can be still further suppressed.

Comparisons among Examples 13 to 15 etc. show that, when the boron atom content is 0.01 to 75 ppt by mass based on the total mass of the treatment liquid, the number of defects originating from boron atoms can be further reduced and that, when the boron atom content is 0.05 to 50 ppt by mass, the number of defects originating from boron atoms can be still further reduced.

Comparisons among Examples 1, 20 to 26, 125 to 131, etc. show that, when the content of the specific metal atoms is 0.001 to 7.5 ppt by mass based on the total mass of the treatment liquid, the ability to suppress the occurrence of defects originating from the treatment liquid is higher.

Each of the treatment liquids in Examples was used as a metal resist washing solution (such as an edge bead remover).

The metal resist composition (2.5 mL) prepared in the [Preparation of metal resist composition] section described above was applied to a 12 inch silicon wafer to form a Sn resist film by spin coating.

Next, one of the treatment liquids (10 mL) in Examples 201 to 226 and Comparative Examples 201 to 209 was applied to the Sn resist film, and the silicon wafer was rotated at 1500 rpm for 45 seconds to dryness. This washing procedure was repeated 10 times. Then a surface defect inspection system (SurfScan SP7 manufactured by KLA) was used to measure the number of defects (in particular, edge bead defects) on the silicon wafer using the method described above, and the washing performance was evaluated according to the following evaluation criteria.

[Ability to Remove Metal Resist]

The following metal resist composition (2.5 mL) in the [Pattern formation] section described above was applied to a 12 inch silicon wafer to form a Sn resist film by spin coating.

Next, one of the treatment liquids (10 mL) in the Examples was applied to the silicon wafer with the Sn resist film formed thereon, and the silicon wafer was rotated at 1500 rpm for 45 seconds to dryness. This washing procedure was repeated 10 times. Then vapor phase decomposition-inductive coupling plasma mass spectrometry (VPD-ICP-MS) was used to measure the amount of remaining Sn (atoms/cm2) by ChemTrace (registered trademark).

Each of the treatment liquids in Examples 201 to 226 and Comparative Examples 201 to 209 was held at a high temperature (85° C.) for 1 hour and then held at a low temperature (5° C.) for 1 hour. This procedure was defined as one cycle (the heating/cooling rate was 5° C./minute). While this cycle was repeated, the treatment liquid was stored for one month under cyclic heating and cooling. The resulting treatment liquid was used to evaluate the washing performance after storage under cyclic heating and cooling using the same method as that for the evaluation of the [Washing performance] described above.

The numbers of defects observed under the surface defect inspection system before and after storage under cyclic heating and cooling were compared, and the resistance to deterioration of the washing performance of the treatment liquid due to storage under cyclic heating and cooling was evaluated according to the following evaluation criteria.

The smaller the increase in the number of defects before and after storage under cyclic heating and cooling, the smaller the degree of deterioration of the treatment liquid during storage, and the better.

Each of the treatment liquids in Examples 201 to 226 and Comparative Examples 201 to 209 was held at a high temperature (85° C.) for 1 hour and then held at a low temperature (5° C.) for 1 hour. This procedure was defined as one cycle (the heating/cooling rate was 5° C./minute). While this cycle was repeated, the treatment liquid was stored for one month under cyclic heating and cooling. The resulting treatment liquid was used to evaluate the ability to remove the metal resist after storage under cyclic heating and cooling using the same method as that for the evaluation of the [Ability to remove metal resist] described above.

The amounts of remaining Sn before and after storage under cyclic heating and cooling were compared to determine the remaining Sn amount ratio (the amount of remaining Sn after storage under cyclic heating and cooling/the amount of remaining Sn before storage under cyclic heating and cooling), and the resistance to deterioration of the ability of the treatment liquid to remove the metal resist due to storage under cyclic heating and cooling was evaluated according to the following evaluation criteria.

The smaller the remaining Sn amount ratio before and after storage under cyclic heating and cooling, the smaller the degree of deterioration of the treatment liquid during storage, and the better.

The compositions of the treatment liquids in the Examples and Comparative Examples, the application of the treatment liquids, and the evaluation results are shown in Table 9.

The notations in Table 9 are the same as the notations in Tables 1 to 8.

Evaluation

After storage under cyclic

Treatment liquid

heating and cooling

Boron
Pb

Ability

Ability

Content

Content
Content
Content
Organic
Content
Content

to remove

to remove

[% by

[% by
[% by
[% by
acid/
[ppt by
[ppt by

Washing
metal
Washing
metal

Example 201
Balance
Acetic acid
15.00
0.01
0.003
5000.00
1
5
Metal resist washing solution
A
A
A
A

Example 202
Balance
Acetic acid
19.80
0.01
0.003
6600.00
1
5
Metal resist washing solution
A
A
A
A

Example 203
Balance
Acetic acid
26.30
0.01
0.003
8766.67
1
5
Metal resist washing solution
A
B
A
A

Example 204
Balance
Acetic acid
33.10
0.01
0.003
11033.33
1
5
Metal resist washing solution
A
C
B
A

Example 205
Balance
Acetic acid
38.90
0.01
0.003
12966.67
1
5
Metal resist washing solution
A
C
B
A

Example 206
Balance
Acetic acid
1.10
0.01
0.003
366.67
1
5
Metal resist washing solution
A
C
A
C

Example 207
Balance
Acetic acid
5.40
0.01
0.003
1800.00
1
5
Metal resist washing solution
A
A
A
A

Example 208
Balance
Acetic acid
15.00
0.01
0.006
2500.00
1
5
Metal resist washing solution;
B
A
A
A

Example 209
Balance
Acetic acid
15.00
0.01
0.009
1666.67
1
5
Metal resist washing solution
C
A
A
A

Example 210
Balance
Acetic acid
15.00
0.01
0.0005
30000.00
1
5
Metal resist washing solution
A
A
B
A

Example 211
Balance
Acetic acid
39.50
0.01
0.0005
79000.00
1
5
Metal resist washing solution
A
C
C
A

Example 212
Balance
Acetic acid
1.10
0.01
0.009
122.22
1
5
Metal resist washing solution
C
C
A
C

Example 213
Balance
Acetic acid
15.00
0.01
0.003
5000.00
15
5
Metal resist washing solution
A
A
A
A

Example 214
Balance
Acetic acid
15.00
0.01
0.003
5000.00
56
5
Metal resist washing solution
A
A
A
A

Example 215
Balance
Acetic acid
15.00
0.01
0.003
5000.00
85
5
Metal resist washing solution
A
A
A
A

Example 216
Balance
Acetic acid
15.00
0.01
0.003
5000.00
0.1
5
Metal resist washing solution
A
A
A
A

Example 217
Balance
Acetic acid
15.00
0.01
0.003
5000.00
0.3
5
Metal resist washing solution
A
A
A
A

Example 218
Balance
Acetic acid
15.00
0.01
0.003
5000.00
0.5
5
Metal resist washing solution
A
A
A
A

Example 219
Balance
Acetic acid
15.00
0.01
0.003
5000.00
0.7
5
Metal resist washing solution
A
A
A
A

Example 220
Balance
Acetic acid
15.00
0.01
0.003
5000.00
1
0.4
Metal resist washing solution
A
A
A
A

Example 221
Balance
Acetic acid
15.00
0.01
0.003
5000.00
1
0.6
Metal resist washing solution
A
A
A
A

Example 222
Balance
Acetic acid
15.00
0.01
0.003
5000.00
1
0.8
Metal resist washing solution
A
A
A
A

Example 223
Balance
Acetic acid
15.00
0.01
0.003
5000.00
1
1
Metal resist washing solution
A
A
A
A

Example 224
Balance
Acetic acid
15.00
0.01
0.003
5000.00
1
3
Metal resist washing solution
A
A
A
A

Example 225
Balance
Acetic acid
15.00
0.01
0.003
5000.00
1
12
Metal resist washing solution
A
A
A
A

Example 226
Balance
Acetic acid
15.00
0.01
0.003
5000.00
1
141
Metal resist washing solution
A
A
A
A

Comparative Example 201
Balance
Acetic acid
43.30
0.01
0.003
14433.33
1
5
Metal resist washing solution
A
D
B
A

Comparative Example 202
Balance
Acetic acid
47.30
0.01
0.003
15766.67
1
5
Metal resist washing solution
A
D
B
A

Comparative Example 203
Balance
Acetic acid
0.09
0.01
0.003
30.00
1
5
Metal resist washing solution
A
D
A
D

Comparative Example 204
Balance
Acetic acid
0.70
0.01
0.003
233.33
1
5
Metal resist washing solution
A
D
A
C

Comparative Example 205
Balance
Acetic acid
15.00
0.01
0.012
1250.00
1
5
Metal resist washing solution
D
A
A
A

Comparative Example 206
Balance
Acetic acid
15.00
0.01
<0.0001
>150000.00
1
5
Metal resist washing solution
D
A
D
A

Comparative Example 207
Balance
Acetic acid
15.00
0.01
0.00012
125000.00
1
5
Metal resist washing solution
C
A
D
A

Comparative Example 208
Balance
Acetic acid
39.50
0.01
0.00012
329166.67
1
5
Metal resist washing solution
C
C
D
A

Comparative Example 209
Balance
Acetic acid
1.10
0.01
0.012
91.67
1
5
Metal resist washing solution
D
C
A
D

As can be seen, the treatment liquids of the invention are useful also as metal resist washing solutions.

As for the tendency of the evaluation results, the tendency of the ability to suppress the occurrence of pattern defects after washing was the same as the tendency of the ability to suppress the occurrence of pattern defects in Tables 1 to 8, and the tendency of the ability to remove the metal resist was the same as the tendency of the resolution in Tables 1 to 8. The tendency of the ability to suppress the occurrence of pattern defects after washing after storage under cyclic heating and cooling was the same as the tendency of the ability to suppress the occurrence of defects originating from the treatment liquid after storage under cyclic heating and cooling in Tables 1 to 8. The tendency of the ability to remove the metal resist after storage under cyclic heating and cooling was the same as the tendency of the resolution after storage under cyclic heating and cooling in Tables 1 to 8.

The treatment liquid in Example 1 was used to perform developing treatment using the same procedure as in the [Formation of pillar pattern] section described above. Then, while the wafer was rotated at 1000 rpm, one rinsing liquid selected from the group consisting of methyl isobutyl carbinol (MIBC), 2-heptanone, PGMEA, PGME, and nBA (n-butyl acetate) was poured over 10 seconds to perform rinsing treatment, and the wafer was rotated at 4000 rpm for 30 seconds to dry the substrate to thereby obtain a pillar pattern with a pitch of 45 nm.

The obtained patterns etc. were used to perform the above-described evaluation procedures in the [Evaluation] section. The evaluation results for each of the above rinsing liquids were the same as those in Example 1.