CN116635794A

CN116635794A - Method for producing thick film resist pattern, thick film solution, and method for producing processed substrate

Info

Publication number: CN116635794A
Application number: CN202180084405.6A
Authority: CN
Inventors: 长原达郎; 山本和磨
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2020-12-17
Filing date: 2021-12-14
Publication date: 2023-08-22
Also published as: TW202231798A; EP4264376A1; JP2022096214A; WO2022129015A1; JP2023554214A; KR20230117233A

Abstract

The present application provides a method for producing a thick-film resist pattern. [ solution ] A method for producing a thick-film resist pattern, comprising the steps of: (1) Applying a resist composition over a substrate, forming a resist layer from the resist composition; (2 a) exposing the resist layer; (2b) Applying a thick film forming solution containing a polymer (A) and a solvent (B) on the resist layer to form a thick film layer; and (3) developing the resist layer and the thick film layer.

Description

Method for producing thick film resist pattern, thick film solution, and method for producing processed substrate

Technical Field

The present application relates to a method for producing a thick film resist pattern, a thick film solution used therefor, and a method for producing a processed substrate.

Background

In recent years, the demand for high integration of LSI has increased, and miniaturization of resist patterns has been demanded. In order to meet such demands, photolithography processes using short wavelength KrF excimer laser (248 nm), arF excimer laser (193 nm), extreme ultraviolet (EUV; 13 nm), X-rays, electron rays, and the like are being put into practical use.

In order to obtain finer patterns, there is a method of covering a resist pattern formed in a range where a conventional method has been stably obtained with a composition containing a polymer, thickening the resist pattern, and making the aperture or separation width finer (for example, patent document 1). This is mainly for the purpose of increasing the width of the resist pattern, and after the resist pattern is developed at a time, a composition containing a polymer is applied.

In addition, even when a thicker resist pattern having a high aspect ratio is required, development using a combination of a vinyl resin and an amine compound has been carried out (patent document 2)

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2014-170190

Patent document 2: japanese patent laid-open No. 2017-165846

Disclosure of Invention

Technical problem to be solved by the application

The present inventors have found that there are one or more problems to be solved by the present application concerning a method for producing a resist pattern. Examples of these include: thick-film forming a fine resist pattern; obtaining a fine resist pattern usable as an etching mask; sufficient resolution can be obtained even with an exposure machine with an increased numerical aperture; obtaining a fine pattern with good shape; obtaining a resist pattern with a large aspect ratio; widening a process window; improving the yield of manufacture.

The present inventors considered and studied as follows.

DOF (Depth of Focus) refers to a range of Focus Depth in which a resist pattern can be formed with a size within a predetermined range of deviation from a target size when exposure is performed with Focus shifted up and down with the same exposure amount.

DOF is represented by the following formula:

k2×λ/NA ²

where k2 is a constant, λ represents an exposure wavelength, and NA represents a numerical aperture.

The larger the DOF, the wider the process window, preferably. However, in high-precision lithography techniques such as IC, the NA of the exposure apparatus tends to increase in the future, and DOF is expected to be narrower.

In EUV exposure, which is expected to be a high definition technique, formation of a fine pattern with a pellicle is increasingly being achieved. The present inventors considered that when a high-definition pattern is used as a mask in a subsequent step, it is preferable to thicken a resist pattern in order to make it more resistant. If the resist pattern is thin, for example, when used as an etching mask, durability as a mask cannot be achieved, and it may occur that the object to be masked is scraped off at the final stage of the etching process.

If the resist film is thick, the process window tends to narrow. For example, if the focus is changed by a minute thickness change of the substrate, the shape of the formed resist pattern may change, and the pattern may be easily collapsed, for example, from a rectangular shape. In addition, in another example, if the exposure amount (Dose) varies, the line width varies, and there is a possibility that pattern bridges or pattern collapse may easily occur. In high definition technology requiring high resolution, thinner resist films are easier to use.

The present application has been made in view of the above-described technical background, and provides a method for producing a thick resist pattern and a thick resist solution used for the method.

Solution for solving the problem

The method for manufacturing a thick film resist pattern according to the present application comprises the steps of:

(1) Applying a resist composition onto a substrate to form a resist layer from the resist composition;

(2a) Exposing the resist layer;

(2b) Applying a thick film forming solution containing a polymer (A) and a solvent (B) to the resist layer to form a thick film layer; and

(3) The resist layer and the thick film layer are developed.

The thickening solution of the present application contains a polymer (a) and a solvent (B) and is used for applying a layer of resist before development of the resist layer to thicken the resist layer.

The method of manufacturing a processed substrate according to the present application comprises the steps of:

forming the thick resist pattern; and

(4) The thick resist pattern is processed using the thick resist pattern as a mask.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present application, one or more of the following effects can be expected.

Thick-film forming a fine resist pattern; obtaining a fine resist pattern usable as an etching mask; sufficient resolution can be obtained even with an exposure machine with an increased numerical aperture; obtaining a fine pattern with good shape; obtaining a resist pattern with a large aspect ratio; widening a process window; improving the yield of manufacture.

Drawings

Fig. 1 is a conceptual diagram showing one embodiment of a method for producing a thick resist pattern.

Detailed Description

[ definition ]

In this specification, unless otherwise defined, the definitions or examples described in this paragraph are followed.

The singular forms include the plural, "a" or "an" and "the" mean "at least one. Elements of certain concepts may be expressed in a variety of forms, and where amounts thereof (e.g., mass% or mole%) are described, then the amounts refer to the sum of these variety.

"and/or" includes all combinations of elements as well as individual uses.

When the numerical range is indicated by "to" or "-/-", they include both endpoints, and the units are common. For example, 5 to 25 mol% means 5 mol% or more and 25 mol% or less.

“C _x～y ”、“C _x ～C _y "AND" C _x "and the like refer to the number of carbons in a molecule or substituent. For example, C _1～6 Alkyl refers to an alkyl chain having 1 to 6 carbons (methyl, ethyl, propyl, butyl, pentyl, hexyl, etc.).

In the case of polymers having a plurality of repeating units, these repeating units are copolymerized. These copolymers may be in the form of alternating copolymers, random copolymers, block copolymers, graft copolymers or mixtures thereof. When the polymer or the resin is represented by the structural formula, n or m and the like described in parentheses are the number of repetitions.

The unit of temperature is in degrees Celsius (Celsius). For example, 20 degrees refers to 20 degrees celsius.

The additive means the compound itself having this function (for example, if it is a base generator, the compound itself generating a base). The compound may be dissolved or dispersed in a solvent and added to the composition. As one embodiment of the present application, it is preferable to contain such a solvent as the solvent (B) or other component in the composition of the present application.

Hereinafter, embodiments of the present application will be described in detail.

< method for producing thick film resist Pattern >

(1) Applying a resist composition over a substrate, forming a resist layer from the resist composition;

(2a) Exposing the resist layer;

(2b) Applying a thick film forming solution containing a polymer (A) and a solvent (B) on the resist layer to form a thick film layer; and

(3) The resist layer and the thick film layer are developed.

Hereinafter, each step will be described with reference to the drawings. For clarity, step (1) and step (2) are performed before step (3) when described. The numbers in () representing the steps represent the order. Wherein the order of (2 a) and (2 b) is arbitrary. The same applies to the following.

Step (1)

In step (1), a resist composition is applied over the substrate to form a resist layer.

Examples of the substrate include a silicon/silicon oxide coated substrate, a silicon nitride substrate, a silicon wafer substrate, a glass substrate, and an ITO substrate.

The resist composition is not particularly limited, but is preferably a chemically amplified resist composition from the viewpoint of forming a fine resist pattern with high resolution, and examples thereof include a chemically amplified PHS-acrylate hybrid EUV resist composition. It is also a preferred embodiment that the resist composition contains a photoacid generator. The preferred resist composition of the application is a positive-working chemically amplified resist composition.

In a typical high resolution positive resist composition, a combination of an alkali-soluble resin having a side chain protected by a protecting group and a photoacid generator is contained. When a resist layer formed from such a composition is irradiated with ultraviolet rays, electron beams, extreme ultraviolet rays, or the like, the photoacid generator releases an acid at the irradiated portion (exposed portion), and a protecting group bonded to the alkali-soluble resin is dissociated by the acid (hereinafter referred to as deprotection). The deprotected alkali-soluble resin is soluble in an alkali developer and thus can be removed by a development treatment. In the case of forming a thick film layer on a resist layer of the present application, if a region of the underlying resist layer is soluble, both the mixed layer and the resist layer of the region are removed. As described later.

The resist composition of the present application may be a negative resist composition. Well-known negative resist compositions or processes may be used. For example, the resist layer and the mixed layer in the unexposed portion are removed by insolubilizing the polymer with a crosslinking agent or using an organic solvent in a developer.

The resist composition is applied over the substrate by a suitable method. Here, in the present application, "above the substrate" includes a case of directly (immediately) applying onto the substrate and a case of applying via other layers. For example, a resist underlayer film (e.g., SOC (Spin On Carbon) and/or adhesion enhancing film) may be formed directly On the substrate, and the resist composition may be applied directly On the resist underlayer film. Preferably, the resist composition is applied directly on the substrate. In another preferred embodiment, the SOC is formed directly on the substrate, the adhesion enhancing film is formed directly on the SOC, and the resist composition is applied directly on the adhesion enhancing film.

The application method is not particularly limited, and examples thereof include coating by spin coating.

The substrate to which the resist composition is applied is preferably heated to form a resist layer. This heating is also called prebaking, for example by a hot plate. The heating temperature is preferably 100-250 ℃; more preferably 100 to 200 ℃; further preferably 100 to 160 ℃. The temperature here is the heating surface temperature of the hot plate. The heating time is preferably 30 to 300 seconds; more preferably 30 to 120 seconds; more preferably 45 to 90 seconds. The heating is preferably carried out in an atmosphere of air or nitrogen; more preferably in an atmospheric atmosphere.

Fig. 1 (i) is a schematic view of a substrate 1 having a resist layer 2 formed thereon. The thickness of the resist layer is selected according to the purpose, and is preferably 10 to 100nm; more preferably 10 to 40nm; more preferably 10 to 30nm.

Step (2 a)

In step (2 a), the resist layer is exposed through a mask as required.

The wavelength of the radiation (light) used for exposure is not particularly limited, and exposure with light having a wavelength of 13.5 to 248nm is preferable. Specifically, krF excimer laser (wavelength 248 nm), arF excimer laser (wavelength 193 nm), EUV (extreme ultraviolet, wavelength 13.5 nm), and the like can be used. EUV light is more preferred. These wavelengths are allowed to be in the range of + -1%.

After exposure, post-exposure heating (PEB) may be performed as needed. The temperature of PEB is 70-150 ℃; preferably from 80 to 120 ℃. The heating time of PEB is 0.3-5 minutes; preferably selected from the range of 0.5 to 2 minutes.

Fig. 1 (ii) is a schematic diagram showing a state in which the resist layer 2 is exposed through a mask in the case where a typical positive type chemically amplified resist composition is used. In the exposure section 4, acid is released from the photoacid generator, whereby the polymer is deprotected and alkali-soluble is high. The alkali solubility of the polymer of the unexposed portion 3 is not changed.

Step (2 b)

In step (2B), a thick film forming solution containing a polymer (a) and a solvent (B) is applied to the resist layer to form a thick film layer. In the present application, the thick film forming solution is not applied between resist patterns (after development of the resist layer).

The substrate to which the thick-film forming solution is applied is preferably heated or spin-dried (more preferably, heated) to form a thick-film layer. The heating is performed, for example, with a hot plate. The heating temperature is preferably 45-150 ℃; more preferably 90 to 130 ℃. The heating time is preferably 30 to 180 seconds; more preferably 45 to 90 seconds. The heating is preferably carried out in an atmosphere of air or nitrogen; more preferably in an atmospheric atmosphere. The heating in (2 b) is also referred to as mix baking.

(2a) And (2 b) are arbitrary. Since exposure through the thick film layer is not required, the step (2 b) is more preferably performed after the step (2 a). The step (2 a) may be performed after the step (2 b), and in this case, exposure is preferably performed while controlling the influence of the penetration of the thick film layer.

Fig. 1 (iii) is a schematic diagram of a state in which the thick film layer 5 is formed on the resist layer 2.

In step (2 b), an insoluble layer is preferably formed in the vicinity of the contact between the thick film layer and the resist layer. Without being limited by theory, it is believed that the polymer penetrates (interpenetrates) each other at the portion where the thick film layer and the resist layer meet, becoming a mixed layer. Whether the mixed layer is soluble in the developer of the subsequent development process depends on whether the underlying resist layer is soluble or insoluble in the developer. If the region of the underlying resist layer is insoluble in the developer, the mixed layer becomes an insoluble layer. The hybrid layer is also soluble if the underlying regions of the resist layer are soluble in the developer.

An example of a positive resist layer will be described. Since the exposed portion of the resist layer is soluble in the developer, the resist layer (matrix component, preferably polymer) in the mixed layer penetrating into the region is dissolved, and the mixed layer is also dissolved. In addition, the exposed portion of the resist layer under the mixed layer is also dissolved. On the other hand, the unexposed portions of the resist layer are insoluble in a developer (e.g., not deprotected). Therefore, the resist layer in the mixed layer penetrating into the region is insoluble, and the mixed layer is also insoluble. In addition, the unexposed portions of the resist layer under the mixed layer are also insoluble.

Fig. 1 (iv) is a schematic diagram of a state in which the insoluble layer 6 is formed. The mixed layer is also formed in the dissolved region (exposure portion in the case of positive type), but is dissolved and removed in the developing step, and therefore is not described in (iv) for the sake of simplicity.

In step (2 b), it is preferable to rinse after forming the thick film layer to remove the upper portion of the thick film layer (thick film layer on the mixed layer). The rinsing may be performed using the same composition as the solvent (B) of the thick film forming solution, preferably using water (for example, DIW). The development in the present application is different from the development described later. That is, the rinse is not used to dissolve the soluble areas of the resist layer to form the resist pattern.

[ Thick film solution ]

The thickening solution of the present application contains a polymer (a) and a solvent (B) and is used for applying before developing the resist layer to thicken the resist layer. The thick film solution of the present application is not applied between developed resist patterns. However, the term "development" after development as used herein does not include development when patterning the resist layer that has been removed. For example, in the case of a design in which resist patterning is continuously performed a plurality of times, although the resist is developed in the preceding step, the thick film forming solution of the present application may be used to form a resist layer in the subsequent step.

(A) Polymer

The polymer (a) used in the present application is not particularly limited as long as it has a good affinity with the resist pattern, and examples thereof include polyacrylic acid and vinyl resin.

Preferably, the polymer (a) is a polymer containing amino groups in the repeating units. Here, amino means primary amino (-NH) ₂ ) Secondary amino (-NHR) and tertiary amino (-NRR'). Here, the amino group also includes an amino group in which nitrogen is bonded to an adjacent element through a double bond as in-n=group. These amino groups may be contained in the side chains of the repeating units or may be contained in the main chain structure of the polymer.

The polymer (a) is preferably a polymer containing at least one selected from the repeating unit (A1) represented by the formula (A1) and the repeating unit (A2) represented by the formula (A2). More preferably, the polymer (a) contains a repeating unit (A1) represented by the formula (A1).

The repeating unit (A1) represented by the formula (A1) is as follows:

wherein,,

R ¹¹ 、R ¹² and R is ¹³ H, C each independently of the other _1-4 Alkyl, or carboxyl. R is R ¹¹ And R is ¹² Preferably H. R is R ¹³ Preferably H or methyl; more preferably H.

L ¹¹ Is a single bond or C _1-4 An alkylene group; more preferably a single bond or methylene; more preferably a single bond.

R ¹⁴ Is a single bond, H or C _1-5 An alkyl group; preferably a single bond, H, methyl, n-ethyl, n-propyl, or n-butyl; more preferably a single bond, H or methyl. R is R ¹⁴ When a single bond is provided, with R ¹³ And (5) bonding.

R ¹⁵ H, C of a shape of H, C _1-5 Alkyl, C _1-5 Acyl, or formyl (-CHO); preferably H, methyl, ethyl, n-propyl, n-butyl, acetyl or formyl; more preferably H, methyl, n-ethyl or n-propyl; further preferred is H or n-propyl.

L ¹¹ In the alkyl group of (2), R ¹⁴ In the alkyl group of (2), R ¹⁵ At least one of an alkyl or acyl group, -CH ₂ Can be replaced by-NH-independently of one another. Preferably R ¹⁵ One of the alkyl or acyl groups-CH ₂ -replaced by-NH-. A mode in which the above-mentioned substitution of-NH-does not occur is also preferable.

R ¹⁴ Or an alkyl group may be bonded to R ¹³ Is co-bonded to form a saturated or unsaturated heterocyclic ring. Preferably R ¹⁴ And R is a single bond of (2) ¹³ Is bonded to form a saturated heterocyclic ring. The mode of not forming the above-mentioned heterocyclic ring is also preferable.

R ¹⁴ The alkyl group of (C) may be bonded to R ¹⁵ Is co-bonded to form a saturated or unsaturated heterocyclic ring. Preferably R ¹⁴ Alkyl and R of (2) ¹⁵ Is bonded to form an unsaturated heterocyclic ring. R used in the above bonding ¹⁴ And/or R ¹⁵ In (C) is-CH ₂ The above-mentioned substitution of-NH-can be carried out. The mode of not forming the above-mentioned heterocyclic ring is also preferable.

m11 and m12 are each independently a number from 0 to 1; preferably 0 or 1; more preferably 0.

The following P1 is described by the formula (a 1): repeating units of polyvinylimidazoles. m11=m12=0. R is R ¹¹ 、R ¹² And R is ¹³ Is H. L (L) ¹¹ Is a single bond. R is R ¹⁴ Is methyl. R is R ¹⁵ Is C ₃ Alkyl (n-propyl), one-CH ₂ -replaced by-NH-. In addition, R ¹⁴ Alkyl and R of (2) ¹⁵ Is bonded to form an unsaturated heterocycle (imidazole).

P2 described below is described by formula (a 1): repeating units of polyallylamine. m11=m12=0. R is R ¹¹ 、R ¹² And R is ¹³ Is H. L (L) ¹¹ Is methylene. R is R ¹⁴ And R is ¹⁵ Is H.

P3 described below is described by formula (a 1): repeating units of a vinylpyrrolidone-vinylimidazole copolymer. The polymer having (A1) has two kinds of repeating units, each represented by formula (A1). The corresponding position of the vinylimidazole is the same as that of P1. To the corresponding position of vinyl pyrrolidoneAnd (5) row description. m11=m12=0. R is R ¹¹ 、R ¹² And R is ¹³ Is H. L (L) ¹¹ Is a single bond. R is R ¹⁴ Is C ₂ Alkyl (ethyl). R is R ¹⁵ Is C ₂ Acyl (CH) ₃ -CO-, acetyl). R is R ¹⁴ Alkyl and R of (2) ¹⁵ Is bound to form a saturated heterocyclic ring (2-pyrrolidone). The repeating units of the corresponding position of the vinyl imidazole and the corresponding position of the vinyl pyrrolidone are 4:6, and the vinyl imidazole and the corresponding position of the vinyl pyrrolidone are randomly copolymerized.

The repeating unit of the polydiallylamine described below is described by the formula (a 1). m11=m12=1. R is R ¹¹ And R is ¹² Is H. L (L) ¹¹ Is methylene, R ¹³ Is methyl. R is R ¹⁴ Is a single bond with R ¹³ Bonding to form a saturated heterocyclic ring. R is R ¹⁵ Is H.

The following repeating units are described by the formula (a 1). m11=m12=0. R is R ¹¹ 、R ¹² And R is ¹³ Is H. L (L) ¹¹ Is a single bond. R is R ¹⁴ Is C ₄ Alkyl (n-butyl). R is R ¹⁵ Is C ₂ Acyl (CH) ₃ -CO-, acetyl). R is R ¹⁴ Alkyl and R of (2) ¹⁵ Is bonded to form a saturated heterocyclic ring.

Examples of the polymer having (A1) include polyvinylimidazole, polyvinylamine, polyallylamine, polydiallylamine, vinylpyrrolidone-vinylimidazole copolymer. The polymer (a) may be a copolymer having two or more kinds (A1), for example, a vinylpyrrolidone-vinylimidazole copolymer or a poly (allylamine-co-diallylamine). Preferably the polymer having (A1) comprises one or two of the repeating units; more preferably one. When a copolymer is used, it is preferable that the polymer having (A1) contains two kinds of repeating units.

The repeating unit (A2) represented by the formula (A2) is as follows:

wherein,,

R ²¹ are each independently H, a single bond, C _1-4 Alkyl or carboxyl (-COOH); preferably H, a single bond or methyl; more preferably H or a single bond; further preferably H. R is R ²¹ Is used for the repeating unit to the other repeating unit (A2). The unused single bond at the end of the polymer may be bonded to H or the like.

R ²² 、R ²³ 、R ²⁴ 、R ²⁵ H, C each independently of the other _1-4 Alkyl or carboxyl; preferably H or methyl; more preferably H.

m21 is a number from 0 to 3; preferably 0 or 1; more preferably 1.

Examples of the polymer having (A2) include polyethylenimine. The polyethyleneimine may be linear or branched; more preferably straight chain.

The linear polyethylenimine is described by formula (a 2). m21=1, r ²¹ 、R ²² 、R ²³ 、R ²⁴ And R is ²⁵ H.

The branched polyethyleneimine is described by formula (a 2). m21=1, r ²¹ Is H or a single bond. R is R ²² 、R ²³ 、R ²⁴ R is R ²⁵ H.

The polymer (a) may be a copolymer having two or more kinds (A2). Preferably, the repeating units in the polymer having (A2) are one or two; more preferably one. The polymer (a) may be a copolymer having (A1) and (A2).

The polymer (a) may be appropriately selected from the above-described group from the viewpoints of the kind of resist composition to be applied, the availability of the polymer, and the like, and is preferably selected from the group consisting of polyvinylimidazole, polyvinylamine, polyallylamine, polydiallylamine, polyethyleneimine, vinylpyrrolidone-vinylimidazole copolymer, and poly (allylamine-co-diallylamine).

The polymer (a) may be a copolymer containing a repeating unit not containing an amino group within a range not impairing the scope of the present application. For example, copolymers containing polyacrylic acid, polymethacrylic acid, polyvinyl alcohol, and the like as copolymerized units can be cited.

In view of affinity with the polymer in the resist, the amino-free repeating unit is preferably 50 mol% or less based on the total repeating units constituting the polymer (a); more preferably 30 mol% or less; more preferably 5 mol% or less. It is also a preferred embodiment of the present application that the amino-free repeating unit is 0 mol% (not contained).

The mass average molecular weight of the polymer (a) is preferably 5,000 ～ 200,000; more preferably 5,000 ～ 150,000; further preferably 6,000 to 10,000. The mass average molecular weight (Mw) in the present application means an average mass molecular weight in terms of polystyrene measured by gel permeation chromatography.

The content of the polymer (A) is preferably 1 to 30% by mass based on the total mass of the thick film forming solution; more preferably 1 to 20 mass%; more preferably 2 to 10 mass%.

The thickening solution contains the polymer (a), but may contain a polymer other than the polymer (a) (preferably a polymer having a repeating unit containing no amino group). The content of the polymer other than the polymer (A) is preferably 0 to 20% by mass based on the total mass of the thick film forming solution; more preferably 0 to 10 mass%; further preferably 0 to 5 mass%; still more preferably 0 mass% (embodiment not included).

(B) Solvent(s)

The solvent (B) is used to dissolve the polymer (A) and other components used as needed. Such a solvent needs not to dissolve the resist layer. The solvent (B) preferably contains water. The water is preferably deionized water (DIW). For use in forming a fine resist pattern, the solvent (B) is preferably a solvent having few impurities. The impurity of the solvent (B) is preferably 1ppm or less; more preferably 100ppb or less; more preferably 10ppb or less. For use in a fine process, it is also a preferable mode of the present application to prepare a thick film solution by filtering a liquid in which a solute is dissolved.

The content of water is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, still more preferably 98 to 100% by mass, and still more preferably 100% by mass based on the total mass of the solvent (B). As a preferred embodiment of the present application, the solvent (B) consists essentially of only water. However, the inclusion of the additive in the thick film solution of the present application in a state where it is dissolved and/or dispersed in a solvent other than water (e.g., a surfactant) is acceptable as a preferable mode of the present application.

Specific examples of the solvent (B) other than water include cyclohexanone, cyclopentanone, propylene Glycol Monomethyl Ether (PGME), propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol 1-monomethyl ether 2-acetate (PGMEA), propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, γ -butyrolactone, ethyl lactate, and a mixture thereof. From the viewpoint of the storage stability of the solution, they are preferable. These solvents may be used in combination of two or more.

The content of the solvent (B) is preferably 70 to 99 mass% based on the total mass of the thick film forming solution; more preferably 80 to 99 mass%; further preferably 90 to 98 mass%.

The pH of the whole thick film forming solution is preferably 5 to 12; more preferably 7 to 12; more preferably 9 to 12.

(C) Acid(s)

The thick-film solution according to the present application may further comprise an acid (C). Without being bound by theory, it is believed that the inclusion of acid (C) can adjust the pH of the thick film forming solution, which tends to become alkaline from polymer (a). It is considered that dissolution of the polymer in the partially deprotected resist layer present on the surface of the resist layer can be suppressed.

As the acid (C), sulfonic acid, carboxylic acid, sulfuric acid, nitric acid, or a mixture of at least any two thereof; preferably sulphonic acid, sulphuric acid or nitric acid; more preferably sulfonic or nitric acid. Examples of the sulfonic acid include p-toluenesulfonic acid, benzenesulfonic acid, p-dodecylbenzenesulfonic acid, 1, 4-naphthalenedisulfonic acid and methanesulfonic acid; p-toluene sulfonic acid is preferred. Examples of the carboxylic acid include acetic acid, formic acid, oxalic acid, maleic acid, fumaric acid, phthalic acid, and succinic acid.

The pH of the whole can be controlled by the addition amount of the acid (C). The strong acid to modify the resist film is preferably not used as the acid (C). For example, it is preferable that the resist film is not deprotected by the acid (C).

The content of the acid (C) is preferably 0 to 20% by mass based on the total mass of the thick film forming solution; more preferably 0 to 15 mass%; further preferably 0.1 to 10 mass%; still more preferably 0.1 to 5% by mass. The thick film solution does not contain acid (C) (0 mass%) and is also one of the preferred modes of the present application.

(D) Surface active agent

The thick film solution according to the present application may further comprise a surfactant (D). By containing the surfactant (D), coatability can be improved. As the surfactant which can be used in the present application, (I) anionic surfactant, (II) cationic surfactant, or (III) nonionic surfactant, more specifically, (I) alkyl sulfonate, alkyl benzene sulfonate, and alkyl benzene sulfonate, (II) dodecylpyridine chloride and dodecylmethyl ammonium chloride, and (III) polyoxyethylene octyl ether, polyoxyethylene lauryl ether, polyoxyethylene acetylene glycol ether, fluorosurfactant (e.g., fluorad (3M), megafac (DIC), surflon (Xudi) and organosiloxane surfactant (e.g., KF-53, KP341 (Xinyue chemical industry) can be exemplified.

These surfactants may be used singly or in combination of two or more.

The content of the surfactant (D) is preferably 0 to 5 mass% based on the total mass of the thick film forming solution; more preferably 0.001 to 2 mass%; more preferably 0.01 to 1% by mass. The absence (0 mass%) of surfactant (D) is also one mode of the present application.

(E) Additive agent

The thick film solution according to the present application may further contain an additive (E) other than the above-mentioned components (A) to (D). The additive (E) is preferably a plasticizer, a cross-linking agent, an antibacterial agent, a bactericide, a preservative, an antifungal agent, a base or at least any of them. Preferably, additive (E) comprises a base; more preferably, it is composed of a base. The base is a low molecular compound, unlike the amino group-containing polymer (a). The molecular weight of the low molecular compound is 50-200; preferably 70 to 150; more preferably from 100 to 125.

Examples of such a base include tertiary amines, diamines, and amine compounds having a cage-type three-dimensional structure.

Examples of the diamine compound include N, N, N ', N' -tetramethyl ethylenediamine, N, N, N ', N' -tetraethyl ethylenediamine, N, N, N ', N' -tetrapropyl ethylenediamine, N, N, N ', N' -tetraisopropyl ethylenediamine, N, N, N ', N' -tetramethyl-1, 2-propylenediamine, N, N, N ', N' -tetraethyl-1, 2-propylenediamine, N, N, N ', N' -tetrapropyl-1, 2-propylenediamine, N, N, N ', N' -tetraisopropyl-1, 2-propylenediamine, N, N, N ', N' -tetramethyl-1, 3-propylenediamine, N, N, N ', N' -tetraethyl-1, 3-propylenediamine, N, N, N ', N' -tetrapropyl-1, 3-propanediamine, N, N ', N' -tetraisopropyl-1, 3-propanediamine, N, N, N ', N' -tetramethyl-1, 2-butanediamine, N, N, N ', N' -tetraethyl-1, 2-butanediamine, N, N, N ', N' -tetrapropyl-1, 2-butanediamine, N, N, N ', N' -tetraisopropyl-1, 2-butanediamine, N, N, N ', N' -tetramethyl-1, 3-butanediamine, N, N, N ', N' -tetraethyl-1, 3-butanediamine, N, N, N ', N' -tetrapropyl-1, 3-butanediamine, N, N ', N' -tetraisopropyl-1, 3-butanediamine, N, N, n ', N ' -tetramethyl-1, 4-butanediamine, N, N, N ', N ' -tetraethyl-1, 4-butanediamine, N, N, N ', N ' -tetrapropyl-1, 4-butanediamine, and N, N ' -tetraisopropyl-1, 4-butanediamine.

Examples of the amine compound having a cage-type stereo structure include 1, 4-diazabicyclo [2.2.2] octane, 2-methyl-1, 4-diazabicyclo [2.2.2] octane, 1, 4-diazabicyclo [2.2.2] octane-2-one, 1, 4-diaza-2-bicyclo [2.2.2] octane, 1, 5-diazabicyclo [3.2.2] nonane, 1, 5-diazabicyclo [3.3.2] decane and 1, 5-diazabicyclo [3.3.3.3] undecane. A preferred embodiment of the application is that the base of additive (E) is 1, 4-diazabicyclo [2.2.2] octane. Without being limited by theory, it is believed that penetration of the thick film forming solution into the resist layer is promoted by the base containing additive (E), and the underlying resist layer expands further.

The content of the additive (E) is preferably 0 to 10 mass% based on the total mass of the thick film forming solution; more preferably 0.001 to 5 mass%; further preferably 0.01 to 4 mass%; still more preferably 0.1 to 3% by mass. The thick film solution of the present application does not contain (0 mass%) additive (E) and is also a preferred embodiment of the present application.

Step (3)

In step (3), the resist layer and the thick film layer are developed.

Examples of the method of applying the developer include spin-coating immersion method, and spray method. The temperature of the developing solution is preferably 5-50 ℃; more preferably 25 to 40 ℃, and the development time is preferably 15 to 120 seconds; more preferably 30 to 60 seconds. After the developer is applied, the developer is removed. The developed resist pattern may also be subjected to a rinse treatment. The rinsing treatment may preferably be performed with water (DIW).

The developing solution is preferably an aqueous alkali solution or an organic solvent; more preferably an aqueous alkali solution. Examples of the aqueous alkali include inorganic bases such as sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium silicate, organic amines such as ammonia, ethylamine, propylamine, diethylamine, diethylaminoethanol, and triethylamine, and aqueous solutions containing quaternary amines such as tetramethylammonium hydroxide (TMAH); more preferably an aqueous TMAH solution; further preferably, the content is 2.38 mass% aqueous TMAH solution.

The above surfactant may be added to the developer.

Fig. 1 (v) shows a state in which a developing solution is applied to the resist layer and the thick film layer, and the developing solution is removed to form a thick film resist pattern 7.

When (the height of the thickened resist pattern) - (the height of the resist pattern formed in the same manner except that the thickening solution is not applied) is used as the thickening amount, the thickening amount is preferably 2 to 20nm; more preferably 2 to 15nm; further preferably 3 to 10nm; more preferably 3 to 8nm. While not being limited by theory, in high-definition lithography such as EUV exposure, the resist film is generally thin, and thus thick by the present application, it is considered that durability as a mask can be ensured when used as an etching mask in a later process.

< method of manufacturing processed substrate and device >

The method of manufacturing a processed substrate of the present application comprises the steps of:

forming the thick film resist pattern; and

Step (4)

In step (4), the thick resist pattern is processed using the thick resist pattern as a mask.

The thick resist pattern is preferably used for processing a resist underlayer film or a substrate (more preferably, a substrate). Specifically, various substrates as a base may be processed using a dry etching method, a wet etching method, an ion implantation method, a metal plating method, or the like with the resist pattern as a mask. Since the resist pattern is thickened, the resist pattern can function as a mask even under more severe conditions, and is therefore suitable for processing by dry etching.

In the case of processing the resist underlayer film using a thick resist pattern, the processing may be performed stepwise. For example, the adhesion enhancing film and the SOC may be processed using a resist pattern, and the substrate may be processed using an SOC pattern. For example, siARC (Si anti-reflective coating) can be used as the adhesion enhancing film.

The method of manufacturing a device according to the present application includes the above method, and preferably further includes a step of forming a wiring on the processed substrate. These processes may be carried out by known methods. Then, the substrate is cut into chips, connected to a lead frame, and packaged with a resin as necessary. In the present application, the packaged device is referred to as a device. Examples of the device include a semiconductor device, a liquid crystal display device, an organic EL display device, a plasma display device, and a solar cell device. The device is preferably a semiconductor device.

Examples (example)

The application is illustrated by the following examples. The embodiments of the present application are not limited to these examples.

[ preparation of thick film solutions 1 to 3]

The polymer (a), the surfactant (D) and the base (E) described in table 1 were dissolved in the solvent (B). The amounts of each of the components are shown in Table 1. The values in Table 1 are the contents (% by mass) of the respective components based on the total mass of the thick film forming solution.

The resulting solution was stirred at room temperature for 60 minutes. After the solute was completely dissolved by visual observation, the solution was filtered through a 0.2 μm fluorinated resin filter to obtain thick film solutions 1 to 3.

TABLE 1

P1: polyvinyl imidazole (Mw: 30,000),

P2: polyallylamine (Mw: 8,000)

P3: vinyl pyrrolidone, vinyl imidazole, random copolymer (m: n=4:6, mw:25,000)

S1: an acetylene glycol polyoxyalkylene ether having the following structure.

Example 1

On the silicon substrate, HMDS (hexamethyldisilazane) treatment was performed at 90 ℃ for 30 seconds. A chemically amplified PHS-acrylate hybrid resist composition (positive type) was applied by spin coating to the HMDS-treated substrate, and heated with a hot plate at 110℃for 60 seconds to form a resist layer having a film thickness of 35 nm. The resist layer was exposed to light while changing the exposure amount through a mask having a size of 18nm (line: width=1:1) using an EUV exposure apparatus (NXE: 3300, B, ASML). Then, post-exposure heating (PEB) was performed at 100 ℃ for 60 seconds. Then, the thick film forming solution 1 was applied onto the resist layer by spin coating to form a thick film layer, and the layer was heated at 130 ℃ for 60 seconds. Then, spin-coating immersion development (paddle development) was performed for 30 seconds using 2.38 mass% TMAH aqueous solution as the developer, and water was dropped while the developer was spin-coated and immersed on the substrate, and the water was continuously dropped while the substrate was rotated, thereby replacing the developer with water. Then, the substrate was rotated at a high speed, and the thick resist pattern of example 1 was dried.

For comparison, a resist pattern to which no thick film forming solution was applied was formed. Specifically, a resist pattern was formed in the same manner as in example 1, except that the application of the thick film forming solution and the subsequent heating were not performed. This is referred to as a comparative resist pattern.

[ evaluation ]

The thick resist pattern of example 1 and the comparative resist pattern were each cut into a substrate, and the cross-sectional shape was observed by SEM (SU 8230, hitachi High-Tech field) to measure the height of the pattern. The (height of the thickened resist pattern) - (height of the comparative resist pattern) was calculated as the thickened amount. The results obtained are shown in Table 2.

Examples 2 and 3 the amount of thickening was calculated in the same manner as in example 1, except that the type of the thickening solution was changed to the solution shown in table 2. The results obtained are shown in Table 2.

TABLE 2

[ description of symbols ]

1. Substrate board

2. Resist layer

3. Unexposed portion

4. Exposure part

5. Thick film layer

6. Insoluble layer

7. Thick film resist pattern

8. The height of the thick film resist pattern.

Claims

1. A method of making a thick film resist pattern comprising the steps of:

(1) Applying a resist composition over the substrate, forming a resist layer from the resist composition (preferably by heating);

(2a) Exposing the resist layer (preferably by EUV light);

(2b) Applying a thick film forming solution containing a polymer (a) and a solvent (B) on the resist layer to form a thick film layer (preferably by heating or spin drying); and

(3) The resist layer and the thick film layer are developed (preferably, development with an aqueous alkali solution or an organic solvent, more preferably, development with an aqueous alkali solution).

2. The method of claim 1, further comprising: in step (2 b), after the thick film layer is formed, rinsing is performed to remove the upper portion of the thick film layer.

3. The method according to claim 1 or 2, wherein in step (2 b), an insoluble layer is formed in a vicinity of a contact between the thick film layer and the resist layer.

4. A method according to any one of claims 1 to 3, wherein the polymer (a) is a polymer containing amino groups in the repeating units.

5. The method according to any one of claims 1 to 4, wherein the polymer (A) is a polymer comprising at least one selected from the repeating unit (A1) represented by the formula (A1) and the repeating unit (A2) represented by the formula (A2),

wherein,,

R ¹¹ 、R ¹² and R is ¹³ H, C each independently of the other _1-4 Alkyl, or carboxyl (preferably H),

L ¹¹ is a single bond or C _1-4 An alkylene group,

R ¹⁴ is a single bond, H or C _1-5 An alkyl group, a hydroxyl group,

R ¹⁵ h, C of a shape of H, C _1-5 Alkyl, C _1-5 An acyl group, or a formyl group,

here, L ¹¹ In the alkyl group of (2), R ¹⁴ In the alkyl group of (2), R ¹⁵ At least one of an alkyl or acyl group, -CH ₂ Can be replaced by-NH-and R ¹⁴ Or alkyl and R ¹³ May be co-bonded to form a saturated or unsaturated heterocyclic ring,

R ¹⁴ alkyl and R of (2) ¹⁵ The alkyl, acyl or formyl groups of (a) may be co-bonded to form a saturated or unsaturated heterocyclic ring, and

m11 and m12 are each independently a number from 0 to 1;

wherein,,

R ²¹ are each independently H, a single bond, C _1-4 Alkyl or carboxyl (preferably H),

R ²² 、R ²³ 、R ²⁴ 、R ²⁵ h, C each independently of the other _1-4 Alkyl or carboxyl (preferably H), and

m21 is a number from 0 to 3.

6. The method of any one of claims 1 to 5, wherein the polymer (a) is selected from the group consisting of polyvinylimidazole, polyvinylamine, polyallylamine, polydiallylamine, polyethylenimine, vinylpyrrolidone-vinylimidazole copolymer, and poly (allylamine-co-diallylamine).

7. A process according to claim 1 to 3, wherein the solvent (B) contains water,

the water content is preferably 80 to 100 mass% (more preferably 90 to 100 mass%, further preferably 98 to 100 mass%, still further preferably 100 mass%) based on the total mass of the solvent (B);

the content of the polymer (a) is preferably 1 to 30 mass% (more preferably 1 to 20 mass%, further preferably 2 to 10 mass%) based on the total mass of the thick-film forming solution; or (b)

The content of the solvent (B) is preferably 70 to 99 mass% (more preferably 80 to 99 mass%, still more preferably 90 to 98 mass%) based on the total mass of the thick film forming solution.

8. The method according to any one of claims 1 to 7, wherein the thick film solution further contains an acid (C),

the content of the acid (C) is preferably 0 to 20 mass% (more preferably 0 to 15 mass%, further preferably 0.1 to 10 mass%, further preferably 0.1 to 5 mass%) based on the total mass of the thick film forming solution;

the pH of the entire thick film forming solution is preferably 5 to 12 (more preferably 5 to 10, still more preferably 6 to 9); or (b)

Preferably, the acid (C) is a sulfonic acid, a carboxylic acid, a sulfuric acid, a nitric acid or a mixture of any of them.

9. The method according to any one of claims 1 to 8, wherein the thick film solution further contains a surfactant (D),

the content of the surfactant (D) is preferably 0 to 5 mass% (more preferably 0.001 to 2 mass%, still more preferably 0.01 to 1 mass%) based on the total mass of the thick-film forming solution;

preferably the thick film solution further comprises an additive (E);

preferably the additive (E) is a plasticizer, a cross-linking agent, an antimicrobial agent, a bactericide, a preservative, an antifungal agent, a base or any mixture thereof; or (b)

The content of the additive (E) is preferably 0 to 10 mass% (preferably 0.001 to 5 mass%, more preferably 0.01 to 4 mass%) based on the total mass of the thick film forming solution.

10. The method of any one of claims 1 to 9, wherein the resist composition is a chemically amplified resist composition.

11. The method of claim 10, wherein the resist composition further comprises a photoacid generator.

12. A thick film forming solution comprising a polymer (A) and a solvent (B) for forming a thick film of a resist layer by applying the solution before developing the resist layer.

13. The thick film solution of claim 12, wherein the thick film solution is not applied between resist patterns.

14. A method of manufacturing a processed substrate comprising the steps of:

forming a thick-film resist pattern as claimed in one or more of claims 1 to 11; and

(4) And processing the thick-film resist pattern as a mask.

15. A method of manufacturing a device comprising the method of claim 14,

preferably, the method further comprises a step of forming a wiring on the processed substrate; or (b)

Preferably the device is a semiconductor device.