TW202411278A - Photoresist film and application thereof - Google Patents

Abstract

A photoresist film and application thereof are provided. The photoresist film has a thickness T with a unit of [mu]m, and when the photoresist film is characterized by ultraviolet-visible spectroscopy, the photoresist film has an absorbance A405nm at 405 nm and an absorbance A436 nm at 436 nm, wherein 0 < A405nm/T ≤ 0.006 and 0 < A436nm/T ≤ 0.005, and the thickness T is 60 [mu]m to 600 [mu]m.

Description

Photoresist film and its application

The present invention relates to a photoresist film, in particular to a high-thickness photoresist film and the application of the photoresist film.

Photoresist films are divided into positive photoresist films and negative photoresist films according to their changes after exposure and development. After exposure, the part of the positive photoresist film exposed to light will dissolve during development, leaving the pattern of the unexposed part after development. After exposure, the part of the negative photoresist film not exposed to light will dissolve during development, leaving the pattern of the exposed part after development.

In the printed circuit board (PCB) industry, photoresist films must be used for etching or electroplating processes to form circuit patterns. As electronic components become more complex and larger in size, the printed circuit board industry has an increasing demand for thick photoresist films with high aspect ratios. However, existing photoresist films cannot stably form high-precision photoresist patterns after exposure and development, and are often accompanied by poor photoresist profiles, or even obvious footing, which affects the accuracy of subsequent etching or electroplating processes, so there is still an urgent need for improvement.

In view of the above technical problems, the present invention aims to provide a photoresist film with a good cross-sectional profile after exposure, which can realize high-precision etching or electroplating processing.

Therefore, one object of the present invention is to provide a photoresist film having a thickness T in micrometers, and when the photoresist film is measured by ultraviolet-visible spectroscopy, it has an absorbance A _405nm for light with a wavelength of 405 nanometers and an absorbance A _436nm for light with a wavelength of 436 nanometers, wherein 0＜A _405nm /T≦0.006 and 0＜A _436nm /T≦0.005, and the thickness T is 60 micrometers to 600 micrometers.

In some embodiments of the present invention, the photoresist film has an absorbance A _365nm for light with a wavelength of 365 nanometers when measured by UV-visible spectroscopy, wherein 0＜A _365nm /T≦0.010.

In some embodiments of the present invention, the UV-Vis spectroscopy is performed using a UV-Vis spectrophotometer under the following conditions: the photoresist film is placed perpendicular to the direction of the incident light source; a diffraction grating is configured as a spectrometer; the test temperature is 25°C; the test pressure is 1 atmosphere; the analysis mode is absorbance; the scanning wavelength range is 190 nm to 1100 nm; the blank sample is air; the scanning speed is 2200 nm/min; the light source switching wavelength from a deuterium lamp to a tungsten filament lamp is 340.8 nm; the sampling interval is 0.2 nm; and the slit width is 2.0 nm.

In some embodiments of the present invention, the photoresist film is a negative photoresist film.

In some embodiments of the present invention, 0＜A _405nm /T≦0.002 and 0＜A _436nm /T≦0.001.

In some embodiments of the present invention, the photoresist film comprises: (A) an alkali-soluble polymer; (B) an ethylenically unsaturated double-bond compound; and (C) a photopolymerization initiator.

In some embodiments of the present invention, the ethylenically unsaturated double bond-containing compound (B) comprises a bifunctional acrylic compound.

In some embodiments of the present invention, the content of the bifunctional acrylic compound is 60 wt% or more based on the total weight of the ethylenically unsaturated bibond-containing compound (B).

Another object of the present invention is to provide a composite film, which comprises: the photoresist film as described above, and a protective film formed on at least one surface of the photoresist film.

In some embodiments of the present invention, the protective film is selected from the following group: polyethylene terephthalate film, polyolefin film and a composite thereof.

In order to make the above-mentioned objectives, technical features and advantages of the present invention more clearly understood, some specific implementation modes are described in detail below.

The following will specifically describe some specific implementation aspects of the present invention; however, the present invention can also be implemented in a variety of different forms, and the protection scope of the present invention should not be interpreted as limited to what is described in the specification.

Unless otherwise specified, the terms "a", "an", "the" and similar terms used in this specification and the patent application should be understood to include both singular and plural forms.

Unless otherwise specified, the terms "first", "second" and similar terms used in this specification and the scope of the patent application are only used to distinguish the elements or components described, and have no special meanings and are not used to represent the order of precedence.

Unless otherwise specified, "(meth)acrylic acid", "(meth)acrylate" and similar terms used in this specification are intended to cover both the groups within the brackets and the groups without them. For example, "(meth)acrylic polymer having a carboxyl group" is intended to cover both acrylic polymer having a carboxyl group and methacrylic polymer having a carboxyl group, and "methyl (meth)acrylate" is intended to cover both methyl acrylate and methyl methacrylate.

In this specification and the scope of the patent application, the weight average molecular weight (Mw) is measured by gel permeation chromatography (GPC) and compared and converted with a standard product, and its unit is "gram/mole (g/mol)".

The present invention is more effective than the prior art in that, by controlling the values of A _405nm /T and A _436nm /T within a specific range, a photoresist film having a good cross-sectional profile after exposure can be provided, thereby enabling high-precision etching or electroplating processing. The following provides a detailed description of the photoresist film of the present invention and its application.

1. Photoresist film

The photoresist film described herein refers to a film comprising a photosensitive resin composition.

The surface of the photoresist film can be covered with a protective film that provides protection and support functions to facilitate the storage of the photoresist film and prevent the photoresist film from adhering to foreign objects or being damaged. In this article, unless otherwise specified, the properties such as "thickness" and "absorbance" are all for the photoresist film itself, and do not include other parts such as the protective film used in combination with it. The following provides a further explanation of the photoresist film.

1.1. Photoresist film Nature

The photoresist film of the present invention has a specific light absorption property. Specifically, when the photoresist film is measured by ultraviolet-visible light spectroscopy, it has an absorbance of A _405nm for light with a wavelength of 405 nanometers and an absorbance of A _436nm for light with a wavelength of 436 nanometers, wherein the relationship between the absorbance A _405nm and the thickness T (unit: micrometer) of the photoresist film satisfies 0＜A _405nm /T≦0.006, and the relationship between the absorbance A _436nm and the thickness T satisfies 0＜A _436nm /T≦0.005. For example, A _405nm /T may be 0.0005, 0.001, 0.0015, 0.002, 0.0025, 0.003, 0.0035, 0.004, 0.0045, 0.005, 0.0055, or 0.006, or a range between any two of the above values. A _436nm /T may be 0.0005, 0.001, 0.0015, 0.002, 0.0025, 0.003, 0.0035, 0.004, 0.0045, or 0.005, or a range between any two of the above values. If A _405nm /T or A _436nm /T exceeds the above range, the cross-sectional profile of the photoresist pattern formed after exposure and development of the photoresist film is not good, and it is not suitable for etching or electroplating processes requiring high precision. In the preferred embodiment of the present invention, 0＜A _405nm /T≦0.002 and 0＜A _436nm /T≦0.001.

In some embodiments of the present invention, the photoresist film has an absorbance A _365nm for light of wavelength 365 nm when measured by UV-Vis spectroscopy, wherein 0＜A _365nm /T≦0.010, and the unit of T is micrometer. For example, A _365nm /T can be 0.0005, 0.001, 0.0015, 0.002, 0.0025, 0.003, 0.0035, 0.004, 0.0045, 0.005, 0.0055, 0.006, 0.0065, 0.007, 0.0075, 0.008, 0.0085, 0.009, 0.0095, or 0.010, or a range between any two of the above values.

In the present invention, UV-Vis spectroscopy is performed using a UV-Vis spectrophotometer under the following conditions: the photoresist film is placed perpendicular to the direction of the incident light source; a diffraction grating is configured as a spectrometer; the test temperature is 25°C; the test pressure is 1 atmosphere; the analysis mode is absorbance; the scanning wavelength range is 190 nm to 1100 nm; the blank sample is air; the scanning speed is 2200 nm/min; the light source switching wavelength from a deuterium lamp to a tungsten filament lamp is 340.8 nm; the sampling interval is 0.2 nm; and the slit width is 2.0 nm. In the aforementioned test conditions, the photoresist film sample used for analysis is obtained by cutting the composite film including the photoresist film and the protective films on both sides of the photoresist film into a size of 5 cm x 3 cm at any position along the transverse direction (TD) and the longitudinal direction (MD), and then removing the protective films on both sides of the cut photoresist film. The photoresist film must be placed perpendicular to the direction of the incident light source in order to correctly measure the absorbance of the photoresist film. The wavelength range of the tungsten filament lamp used as the incident light source is greater than 340.8 nm. In addition, the "sampling interval" refers to taking a data point every 0.2 nm in the scanning wavelength range of 190 nm to 1100 nm and recording its value.

The absorbance values of the photoresist film of the present invention such as A _405nm , A _436nm , and A _365nm can be adjusted by adjusting the composition of the photoresist film or the drying conditions of the photoresist film manufacturing process. For example, the composition of the photoresist film can be adjusted by selecting the type and content of additives, and the additives include but are not limited to photopolymerization initiators, light absorbers, dyes, etc. After reading the instructions of the present invention, those with ordinary knowledge in the technical field to which the present invention belongs can achieve the desired absorbance according to routine experiments.

The thickness T of the photoresist film of the present invention is a thickness value expressed in micrometers, and the range is 60 micrometers to 600 micrometers, preferably 100 micrometers to 600 micrometers, for example, 60 micrometers, 70 micrometers, 80 micrometers, 90 micrometers, 100 micrometers, 110 micrometers, 120 micrometers, 130 micrometers, 140 micrometers, 150 micrometers, 160 micrometers, 170 micrometers, 180 micrometers, 190 micrometers, 200 micrometers, 210 micrometers, 220 micrometers, 230 micrometers, 240 micrometers, 250 micrometers, 260 micrometers, 270 micrometers, 280 micrometers, 290 micrometers, 300 micrometers, 310 micrometers, 320 micrometers, 330 micrometers, 340 micrometers, 350 micrometers, 360 micrometers, 370 micrometers, 380 micrometers, 390 micrometers, 400 micrometers, 410 micrometers, 420 micrometers, 430 micrometers, 440 micrometers, 450 micrometers, 460 micrometers, 470 micrometers, 480 micrometers, 490 micrometers, 500 micrometers, 510 micrometers, 520 micrometers, 530 micrometers, 540 micrometers, 550 micrometers, 560 micrometers, 570 micrometers, 580 micrometers, 590 micrometers, 600 micrometers, 610 micrometers, 620 micro , 310 micrometers, 320 micrometers, 330 micrometers, 340 micrometers, 350 micrometers, 360 micrometers, 370 micrometers, 380 micrometers, 390 micrometers, 400 micrometers, 410 micrometers, 420 micrometers, 430 micrometers, 440 micrometers, 450 micrometers, 460 micrometers, 470 micrometers, 480 micrometers, 490 micrometers, 500 micrometers, 510 micrometers, 520 micrometers, 530 micrometers, 540 micrometers, 550 micrometers, 560 micrometers, 570 micrometers, 580 micrometers, 590 micrometers, or 600 micrometers, or a range formed by any two of the above values. Since the higher the photoresist thickness, the higher the plating thickness of the metal conductive layer, the photoresist film of the present invention is particularly suitable for application in 2.5D and 3D integrated circuit packaging, and can be used as a patterning application before the conductive layer is electroplated.

The photoresist film of the present invention can be a positive photoresist film or a negative photoresist film. In some embodiments of the present invention, the photoresist film of the present invention is a negative photoresist film, that is, after the photoresist film is exposed, the part not exposed to light will be dissolved during development, and the pattern of the exposed part will remain after development.

In one embodiment of the present invention, the photoresist film of the present invention is a dry film, i.e., a resin film with a low solvent content. The low solvent content means that the content of the solvent is less than 10% by weight, specifically less than 5% by weight, and more specifically 0.1 to 4% by weight, based on the total weight of the photoresist film. Compared with ink-like or liquid-like wet films, dry films are less likely to flow or deform due to their low solvent content, and can be attached to a substrate without additional processes such as coating and drying, so they are easier to control and have good operability.

1.2. Photoresist film Composition

Under the conditions of 0＜A _405nm /T≦0.002 and 0＜A _436nm /T≦0.001, the composition of the photoresist film of the present invention can be adjusted as needed. In some embodiments of the present invention, the photoresist film is a negative photoresist film, which includes (A) an alkali-soluble polymer, (B) an ethylenically unsaturated double bond compound, and (C) a photopolymerization initiator, and can further include additives as needed.

1.2.1. （ A ) Alkaline soluble polymer

The alkali-soluble polymer is a polymer having a carboxyl group, and examples thereof include but are not limited to acrylic polymers having a carboxyl group, vinyl aromatic polymers having a carboxyl group, norbornene polymers having a carboxyl group, epoxy polymers having a carboxyl group, amide polymers having a carboxyl group, amide epoxy polymers having a carboxyl group, alkyd polymers having a carboxyl group, and phenolic polymers having a carboxyl group. Each of the aforementioned alkali-soluble polymers can be used alone or in combination. In some embodiments of the present invention, the alkali-soluble polymer is an acrylic polymer having a carboxyl group.

The alkali-soluble polymer can be obtained by polymerizing one or more polymerizable monomers having a carboxyl group, or by copolymerizing one or more polymerizable monomers having a carboxyl group with other polymerizable monomers not having a carboxyl group, and thus may contain repeating units derived from a polymerizable monomer having a carboxyl group, or contain repeating units derived from a polymerizable monomer having a carboxyl group and repeating units of other polymerizable monomers.

In some embodiments of the present invention, the alkali-soluble polymer has repeating units derived from at least one first polymerizable monomer and repeating units derived from at least one second polymerizable monomer, wherein the first polymerizable monomer has a carboxyl group, and examples thereof include but are not limited to (meth)acrylic acid, α-bromo(meth)acrylic acid, α-chloro(meth)acrylic acid, β-diphenylimide(meth)acrylic acid, β-styryl(meth)acrylic acid, propiolic acid, fumaric acid, cinnamic acid, crotonic acid, itaconic acid, and maleic acid. The second polymerizable monomer does not have a carboxyl group, and examples thereof include but are not limited to (meth)acrylate compounds, such as methyl(meth)acrylate, ethyl(meth)acrylate, n-propyl(meth)acrylate, isopropyl(meth)acrylate, n-butyl(meth)acrylate, isobutyl(meth)acrylate, isooctyl(meth)acrylate (2-ethylhexyl)acrylate, and isobutyl(meth)acrylate. (meth)acrylate), tributyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, 1-methyl-cyclopentyl (meth)acrylate, 1-methyl-cyclohexyl (meth)acrylate, 2-methyl-adamantyl (meth)acrylate, 2-ethyl-adamantyl (meth)acrylate, 2-butyl-adamantyl (meth)acrylate, tetrahydrofuranyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl acrylate, epoxypropyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate; (meth)acrylonitrile; vinyl ester compounds, such as vinyl acetate and vinyl n-butyl ester; vinyl aromatic compounds, such as styrene, vinyl naphthalene, 3-acetoxystyrene, 4-acetoxystyrene, vinyl toluene, α-methylstyrene; norbornene; acrylamide; maleate compounds, such as monomethyl maleate, monoethyl maleate, monoisopropyl maleate; and derivatives of the aforementioned polymerizable monomers. The first monomer and the second monomer can be used independently or in combination.

In a preferred embodiment of the present invention, the alkali-soluble polymer is obtained by copolymerizing (meth)acrylic acid with one or more (meth)acrylate compounds, and thus comprises repeating units derived from (meth)acrylic acid and repeating units derived from (meth)acrylate compounds. The weight ratio of (meth)acrylic acid to (meth)acrylate compounds may be 1:20 to 1:1, more specifically 1:6 to 1:4. For example, the weight ratio of (meth)acrylic acid to (meth)acrylate compounds may be 1:20, 1:19, 1:18, 1:17, 1:16, 1:15, 1:14, 1:13, 1:12, 1:11, 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3, 1:2, or 1:1, or a range consisting of any two of the above values.

The molecular weight of the alkali-soluble polymer may be 10,000 to 180,000, preferably 40,000 to 80,000, for example, 10,000, 15,000, 20,000, 25,000, 30,000, 35,000, 40,000, 45,000, 50,000, 55,000, 60,000, 65,000, 70,000, 75,000, 80,000, 85,000, 90,000, 95,000, 100,000, 105,000, 110,000, 115,000, 120,000, 125,000, 130,000, 135,000, 140,000. , 145,000, 150,000, 155,000, 160,000, 165,000, 170,000, 175,000, or 180,000, or a range formed by any two of the foregoing values.

In the photoresist film of the present invention, the content of the alkali-soluble polymer may be 20 wt % to 85 wt %, more specifically 40 wt % to 80 wt %, and even more specifically 50 wt % to 75 wt % based on the total weight of the photoresist film. For example, the content of the alkali-soluble polymer may be 20 wt %, 22.5 wt %, 25 wt %, 27.5 wt %, 30 wt %, 32.5 wt %, 35 wt %, 37.5 wt %, 40 wt %, 42.5 wt %, 45 wt %, 47.5 wt %, 50 wt %, 52.5 wt %, 55 wt %, 57.5 wt %, 60 wt %, 62.5 wt %, 65 wt %, 67.5 wt %, 70 wt %, 72.5 wt %, 75 wt %, 77.5 wt %, 80 wt %, 82.5 wt %, or 85 wt %, or a range consisting of any two of the above values.

1.2.2. （ B ) Ethylenically unsaturated double bond compounds

The ethylenically unsaturated di-bond compound refers to a compound having at least one reactive ethylene functional group, preferably a difunctional compound having two reactive ethylene functional groups. In some embodiments of the present invention, the ethylenically unsaturated di-bond compound comprises a monofunctional or multifunctional acrylic compound, and the monofunctional or multifunctional acrylic compound is preferably a difunctional acrylic compound, examples of which include but are not limited to ethoxylated trihydroxymethylpropane triacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, polypropylene glycol diacrylate, tri((methyl)acrylate, 1,6-hexanediol di ... ethoxylated urate di(meth)acrylate, propoxylated urate di(meth)acrylate, ethoxylated/propoxylated urate di(meth)acrylate, ethoxylated tris(methacryloyloxyisocyanate) hexamethylene isocyanate, acrylated tris(methacryloyloxyisocyanate) hexamethylene isocyanate, ethoxylated/propoxylated tris(methacryloyloxyisocyanate) hexamethylene isocyanate. In addition, based on the total weight of the ethylenically unsaturated double bond-containing compound, the content of the bifunctional acrylic compound is preferably 60 wt % or more, for example, 60 wt %, 62.5 wt %, 65 wt %, 67.5 wt %, 70 wt %, 72.5 wt %, 75 wt %, 77.5 wt %, 80 wt %, 82.5 wt %, 85 wt %, 87.5 wt %, 90 wt %, 92.5 wt %, 95 wt %, 97.5 wt %, or 100 wt %, or a range formed by any two of the above values.

In some embodiments of the present invention, the ethylenically unsaturated double bond-containing compound comprises ethoxylated trihydroxymethylpropane triacrylate and ethoxylated bisphenol A dimethacrylate.

In the photoresist film of the present invention, the content of the ethylenically unsaturated double bond compound may be 5 wt % to 70 wt %, more specifically 15 wt % to 50 wt %, and even more specifically 20 wt % to 45 wt %, based on the total weight of the photoresist film. For example, the content of the ethylenically unsaturated double bond compound can be 5 wt%, 7.5 wt%, 10 wt%, 12.5 wt%, 15 wt%, 17.5 wt%, 20 wt%, 22.5 wt%, 25 wt%, 27.5 wt%, 30 wt%, 32.5 wt%, 35 wt%, 37.5 wt%, 40 wt%, 42.5 wt%, 45 wt%, 47.5 wt%, 50 wt%, 52.5 wt%, 55 wt%, 57.5 wt%, 60 wt%, 62.5 wt%, 65 wt%, 67.5 wt%, or 70 wt%, based on the total weight of the photoresist film, or a range consisting of any two of the above values.

1.2.3. （ C ）Photopolymerization initiator

Photopolymerization initiators refer to substances that can initiate polymerization reactions under the action of light. There is no particular limitation on the types of photopolymerization initiators, and examples thereof include but are not limited to imidazole compounds, ketone compounds, quinone compounds, benzoin or benzoin ether compounds, polyhalogen compounds, triazine compounds, organic peroxides, onium salt compounds, and other photopolymerization initiators commonly used in the art. The aforementioned photopolymerization initiators can be used independently or in combination.

Examples of the aforementioned imidazole compounds include, but are not limited to, 2,4,6-triaryl imidazole dimers, such as 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, and 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer.

Examples of the aforementioned ketone compounds include, but are not limited to, benzophenone, 4,4-bis(dimethylamino)benzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 4,4'-dimethoxybenzophenone, 4-dimethylaminobenzophenone, 4-dimethylaminoacetophenone, xanthone, thiothione, 2-chlorothiothione, 2,4-diethylthiothione, acridone, α-hydroxyacetophenone, α-aminoacetophenone, α-hydroxycycloalkylphenyl ketone, and dialkoxyacetophenone.

Examples of the aforementioned quinone compounds include, but are not limited to, camphorquinone, benzylanthraquinone, 2-tert-butylanthraquinone, and 2-methylanthraquinone.

Examples of the aforementioned benzoin or benzoin ether compounds include, but are not limited to, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, and benzoin phenyl ether.

Examples of the aforementioned polyhalogen compound include, but are not limited to, carbon tetrabromide, phenyltribromomethylsulfonium, and phenyltrichloromethylketone.

Examples of the aforementioned triazine compound include, but are not limited to, 2,4,6-tris(trichloromethyl)-s-triazine, 2-methoxy-4,6-bis(trichloromethyl)-s-triazine, 2-amino-4,6-bis(trichloromethyl)-s-triazine, and 2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine.

Examples of the aforementioned organic peroxides include, but are not limited to, methyl ethyl ketone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, benzoyl peroxide, di-tertiary butyl peroxyisophthalate, 2,5-dimethyl-2,5-di(benzylperoxy)hexane, tertiary butyl peroxybenzoate, a,a'-bis(tertiary butylperoxyisopropyl)benzene, diisopropylbenzene peroxide, and 3,3',4,4'-tetrakis-(tertiary butylperoxycarbonyl)benzophenone.

Examples of the aforementioned onium salt compounds include, but are not limited to, diaryliodonium salts and triarylsonium salts obtained by using a combination of biphenylyl iodonium, 4,4'-dichlorobiphenylyl iodonium, 4,4'-dimethoxybiphenylyl iodonium, 4,4'-di-tert-butylbiphenylyl iodonium, 4-methyl-4'-isopropyl-biphenylyl iodonium or 3,3'-dinitrobiphenylyl iodonium with chloride, bromide, tetrafluoroborate, hexafluorophosphate, hexafluoroarsenate, hexafluoroantimonate, tetrakis(pentafluorophenyl)borate or trifluoromethanesulfonic acid.

Examples of other common photopolymerization initiators in the art include, but are not limited to, fluorene, bisacylphosphine oxide compounds, azinium compounds, organic boron compounds, phenylglyoxylate, and titanocene.

In some embodiments of the present invention, the photopolymerization initiator is an imidazole compound or a ketone compound.

In the photoresist film of the present invention, the content of the photopolymerization initiator may be 0.1 wt % to 15 wt %, more specifically 0.5 wt % to 10 wt %, and even more specifically 1 wt % to 5 wt %, based on the total weight of the photoresist film. For example, relative to the total weight of the photoresist film, the content of the photopolymerization initiator may be 0.1 wt %, 0.5 wt %, 1 wt %, 1.5 wt %, 2 wt %, 2.5 wt %, 3 wt %, 3.5 wt %, 4 wt %, 4.5 wt %, 5 wt %, 5.5 wt %, 6 wt %, 6.5 wt %, 7 wt %, 7.5 wt %, 8 wt %, 8.5 wt %, 9 wt %, 9.5 wt %, 10 wt %, 10.5 wt %, 11 wt %, 11.5 wt %, 12 wt %, 12.5 wt %, 13 wt %, 13.5 wt %, 14 wt %, 14.5 wt %, or 15 wt %, or a range consisting of any two of the above values.

1.2.4. Additives as needed

Under the conditions of 0＜A _405nm /T≦0.002 and 0＜A _436nm /T≦0.001, the photoresist film of the present invention may further include an additive to specifically improve the properties of the photoresist film. Examples of the additive include but are not limited to light absorbers, dyes, pigments, free radical inhibitors, and surfactants. Each of the additives can be used alone or in any combination. In some embodiments of the present invention, the photoresist film further includes a light absorber to adjust the absorbance of the photoresist film to a specific light wavelength to a desired range.

1.3. Photoresist film Preparation

There is no special limitation on the preparation method of the photoresist film of the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs can prepare the photoresist film based on the disclosure of the present specification. Taking the preparation of the negative photoresist film mentioned above as an example, the components of the photoresist film, including (A) an alkali-soluble polymer, (B) an ethylene-unsaturated double bond compound, (C) a photopolymerization initiator, and other additives as required, can be uniformly mixed with a stirrer and dissolved or dispersed in a solvent to form a resin composition. The obtained resin composition is then coated on a substrate and dried to obtain a photoresist film. The detailed preparation method is illustrated in the following embodiment and is not described in detail here.

2. Photoresist film Applications

Before use, the photoresist film is generally covered with a protective film that can provide protection and support functions on both surfaces of the photoresist film to facilitate the storage of the photoresist film and prevent the photoresist film from adhering to foreign matter or being damaged. Therefore, the present invention further provides a composite film, which includes the photoresist film of the present invention as described above, and a protective film formed on at least one surface of the photoresist film. In a preferred embodiment of the present invention, the protective film is formed on both surfaces of the photoresist film, and the materials of the protective films formed on the two surfaces of the photoresist film can be the same or different.

There is no particular limitation on the type of protective film, and various materials known in the technical field to which the present invention belongs can be used. For example, the protective film that can be used in the present invention can be selected from the following groups: polyethylene terephthalate film (PET film), polyolefin film and the aforementioned composite. Examples of the polyolefin film include but are not limited to polyethylene film (PE film) and polypropylene film (PP film), such as oriented polypropylene film, and the composite can be a composite of polyethylene terephthalate film and polyolefin film, or a composite of different polyolefin films. In a preferred embodiment of the present invention, the composite film includes a PET film formed on one surface of the photoresist film and a PE film formed on the other surface of the photoresist film.

The preparation method of the composite film of the present invention is not particularly limited, and methods known in the field to which the present invention belongs can be used. A person with ordinary knowledge in the technical field to which the present invention belongs can prepare the composite film based on the disclosure of the specification of this case. For example, a protective film layer can be stacked on two surfaces of a photoresist film to provide a layer, and the layer is pressurized to obtain a composite film. Alternatively, a resin composition for forming a photoresist film can be first applied to a first protective film and dried to form a photoresist film on the first protective film, and then a second protective film is attached to the surface of the photoresist film that is not in contact with the first protective film, thereby obtaining a composite film. Alternatively, the resin composition for forming a photoresist film may be squeezed between two protective films having a fixed distance, and then dried to form a photoresist film between the two protective films.

3. Embodiment

3.1. Measurement method

[Photoresist film thickness]

The prepared composite film including the photoresist film was cut into 5 cm × 3 cm pieces, and the protective films on both sides of the photoresist film were removed. The photoresist film was placed on the base (MS-11C base) of a film thickness meter (model: Nikon Digimicro MFC-101+MS-11C, purchased from Nikon Corporation (Nikon)), and the MFC-101 tester was used for testing. The measuring pressure was 140 grams, and the thickness of the photoresist film at 10 different points was measured and the average value was taken.

[Photoresist film absorbance]

The prepared composite film including the photoresist film was cut into 5 cm×3 cm pieces, and the protective films on both sides of the photoresist film were removed. The photoresist film was measured using an ultraviolet-visible spectrophotometer (model: Shimadzu UV-1601, purchased from Shimadzu) in the following manner. The photoresist film was placed perpendicular to the incident light source using a fixture under the following conditions: a diffraction grating was used as a spectrometer; the test temperature was 25°C; the test pressure was 1 atmosphere; the analysis mode was absorbance; the scanning wavelength range was 190 nm to 1100 nm; the blank sample was air; the scanning speed was 2200 nm/min; the light source switching wavelength from deuterium lamp to tungsten filament lamp was 340.8 nm; the sampling interval was 0.2 nm; the slit width was 2.0 nm; and the Shimadzu UV Probe V1.11 software was used for analysis to obtain the absorbance A _405nm of light with a wavelength of 405 nm. , the absorbance of light with a wavelength of 436 nanometers is A _436nm , and the absorbance of light with a wavelength of 365 nanometers is A _365nm .

[Cross-sectional shape of photoresist pattern]

A Ti(600A)/Cu(2000A) wafer with a diameter of 6 inches and a thickness of 625 microns was taken. The wafer was preheated at 80°C for 10 minutes in a batch oven, and the surface temperature of the wafer was maintained at 50°C before lamination. The photoresist film was placed on the wafer and pressed with a laminator (model: CSL-M25E, purchased from Zhisheng Industrial). The laminator temperature was 105°C, the pressure was 3 kg/cm2, and the laminating speed was 2.0 m/min. After lamination, the excess film was removed and the obtained photoresist film sample was left to cool to room temperature for 15 minutes.

The developing point test was conducted under the following conditions: using a 0.9% to 1.1% Na ₂ CO ₃ aqueous solution, setting the liquid temperature to 29°C to 31°C, and the spray pressure to 2.0 kg/cm 2 ; placing the photoresist film sample together with the wafer into a developer (model: S30C, purchased from Zaoli Corporation), turning on the rinsing and swinging, with the developing section length of 1.3 meters and the washing section length of 1.3 meters; and recording the time when the photoresist is completely developed and removed as the developing point (Minimum Developing Time, MDT).

The photoresist film was exposed using an exposure machine (model: Ultratech Stepper Spectrum, purchased from Ultratech). The wavelengths of the exposure light sources were 405 nm, 436 nm, and 365 nm, respectively. The exposure was continued until the exposure energy reached 800 mJ/cm2. The aspect ratio of the photoresist pattern to be formed was set to 2.0, and the ratio of the photoresist pattern portion to the non-pattern portion (i.e., the diameter of the via: the photoresist width) was set to 1:1. After the exposure was completed, the exposed photoresist film was left to stand for 30 minutes. Then, the exposed photoresist film is developed using a 0.9% to 1.1% Na ₂ CO ₃ aqueous solution, the liquid temperature is set to 29° C. to 31° C., the spray pressure is set to 2.0 kg/cm 2 , and the development time is twice the development time (MDT*2) to obtain a developed photoresist film.

The developed photoresist film and wafer were split using a wafer cutter at the non-patterned part of the photoresist (i.e., through-hole) and the cross-sectional shape of the photoresist pattern was observed using a scanning electron microscope. The specimen was tilted 75 ^degrees and the magnification was 200 times. A photoresist cross section is randomly selected to measure the photoresist width at 1/25, 2/25, 3/25, 4/25, and 5/25 of the total photoresist thickness from the upper edge of the photoresist (one side away from the wafer), and the average of the width values measured at the five locations is taken as the upper width; and the photoresist width is measured at 1/25, 2/25, 3/25, 4/25, and 5/25 of the total photoresist thickness from the lower edge of the photoresist (one side in contact with the wafer), and the average of the width values measured at the five locations is taken as the lower width. If the value of "|(upper width - lower width)|/thickness" is less than 0.04, it is recorded as "rectangular", indicating that the cross-sectional shape of the photoresist pattern is good; if the value of "|(upper width - lower width)|/thickness" is greater than 0.04, it is recorded as "trapezoidal", indicating that the cross-sectional shape of the photoresist pattern is not good. "|(upper width - lower width)|" in the formula represents an absolute value.

[Photoresist pattern foot length]

A Ti(600A)/Cu(2000A) wafer with a diameter of 6 inches and a thickness of 625 microns was taken. The wafer was preheated at 80°C for 10 minutes in a batch oven, and the surface temperature of the wafer was maintained at 50°C before lamination. The photoresist film was placed on the wafer and pressed with a laminator (model: CSL-M25E, purchased from Zhisheng Industrial). The laminator temperature was 105°C, the pressure was 3 kg/cm2, and the laminating speed was 2.0 m/min. After lamination, the excess film was removed and the obtained photoresist film sample was left to cool to room temperature for 15 minutes.

Exposure was performed using an exposure machine (model: Ultratech Stepper Spectrum, purchased from Ultratech). The wavelengths of the exposure light sources were 405 nm, 436 nm, and 365 nm, respectively. Exposure was continued until the exposure energy reached 800 mJ/cm2. The aspect ratio of the photoresist pattern to be formed was set at 2.0, and the ratio of the photoresist pattern portion to the non-pattern portion (i.e., the diameter of the via: the photoresist width) was set at 1:1. After the exposure was completed, the exposed photoresist film was left to stand for 30 minutes to 24 hours. Then, the exposed photoresist film is developed using a 0.9% to 1.1% Na ₂ CO ₃ aqueous solution, with the liquid temperature set at 29°C to 31°C, the spray pressure set at 2.0 kg/cm2, and the development time at 2 times the development point time (MDT*2) and 4 times the development point time (MDT*4) to obtain a developed photoresist film. The development point (MDT) is based on the development point test result of the [cross-sectional shape of the photoresist pattern].

Use a wafer cutter to cut the developed photoresist film and wafer cracks at the non-patterned part of the photoresist (i.e., through-hole) and observe the cross-sectional shape of the photoresist pattern with a scanning electron microscope. The specimen is tilted 75 ^degrees and the magnification is 5000 times. Randomly select a photoresist cross section and choose the side with the bottom protruding more toward the non-photoresist pattern part to calculate the foot length. The calculation method is: take the photoresist side wall position at 1/5 of the total photoresist thickness along the bottom edge of the photoresist as the reference point, extend a reference line perpendicular to the wafer surface from the reference point downward, and the length from the intersection of the reference line and the wafer surface to the intersection of the photoresist side wall and the wafer surface is the foot length.

3.2. Photoresist film Preparation and testing

3.2.1. Alkaline Solubility Polymer Synthesis

According to the following Synthesis Examples 1 to 3, acrylic acid-based polymers having a carboxyl group were prepared as alkaline-soluble polymers.

[Synthesis Example 1]

15 g of methacrylic acid, 50 g of methyl methacrylate, 30 g of butyl acrylate, and 5 g of butyl methacrylate as copolymer monomers were mixed with 1.0 g of azobisisoheptanenitrile to prepare solution a1. Separately, 0.5 g of azobisisoheptanenitrile was dissolved in 20 g of ethyl acetate solvent to prepare solution b1.

A flask equipped with a stirrer, a reflux cooler, a thermometer, and a dropper was prepared. 80 g of ethyl acetate solvent was added to the flask and heated to 70°C. Solution a1 was then added dropwise to the flask at a constant rate for 3 hours, and then the temperature of the solution in the flask was maintained at 70°C and stirred for 2 hours. Then, solution b1 was added dropwise to the flask at a constant rate for 0.5 hours, and then the temperature of the solution in the flask was maintained at 70°C and stirred for 5 hours. Thereafter, the solution in the flask was heated to 90°C and stirred for 5 hours to allow the reaction to proceed fully. After the reaction was completed, the product was cooled to room temperature to obtain an acrylic polymer A having a carboxyl group (hereinafter also referred to as "polymer A") having a weight average molecular weight of 65,000 and a solid content of 50 wt %.

[Synthesis Example 2]

15 g of methacrylic acid, 65 g of methyl methacrylate, 10 g of butyl acrylate, and 10 g of butyl methacrylate as copolymer monomers were mixed with 0.75 g of azobisisoheptanenitrile to prepare solution a2. Separately, 0.5 g of azobisisoheptanenitrile was dissolved in 20 g of ethyl acetate solvent to prepare solution b2.

A flask equipped with a stirrer, a reflux cooler, a thermometer, and a dropper was prepared. 102.2 g of ethyl acetate solvent was added to the flask and heated to 70°C. Solution a2 was then added dropwise to the flask at a constant rate for 3 hours, and then the temperature of the solution in the flask was maintained at 70°C and stirred for 2 hours. Then, solution b2 was added dropwise to the flask at a constant rate for 0.5 hours, and then the temperature of the solution in the flask was maintained at 70°C and stirred for 5 hours. Thereafter, the solution in the flask was heated to 90°C and stirred for 5 hours to allow the reaction to proceed fully. After the reaction was completed, the product was cooled to room temperature to obtain an acrylic polymer B having a carboxyl group (hereinafter also referred to as "polymer B") having a weight average molecular weight of 65,000 and a solid content of 45 wt %.

[Synthesis Example 3]

20 g of methacrylic acid, 45 g of methyl methacrylate, and 35 g of 2-ethylhexyl acrylate as copolymer monomers were mixed with 0.5 g of azobis(isoheptanonitrile) to prepare solution a3. Separately, 0.5 g of azobis(isoheptanonitrile) was dissolved in 20 g of ethyl acetate solvent to prepare solution b3.

A flask equipped with a stirrer, a reflux cooler, a thermometer, and a dropper was prepared. 80 g of ethyl acetate solvent was added to the flask and heated to 70°C. Solution a3 was then added dropwise to the flask at a constant rate for 3 hours, and then the temperature of the solution in the flask was maintained at 70°C and stirred for 2 hours. Then, solution b3 was added dropwise to the flask at a constant rate for 0.5 hours, and then the temperature of the solution in the flask was maintained at 70°C and stirred for 5 hours. Thereafter, the temperature of the solution in the flask was heated to 90°C and stirred for 5 hours to allow the reaction to proceed fully. After the reaction was completed, the product was cooled to room temperature to obtain an acrylic polymer C having a carboxyl group (hereinafter also referred to as "polymer C") having a weight average molecular weight of 55,000 and a solid content of 50 wt %.

3.2.2. Photoresist film Preparation

In the following embodiments and comparative examples, the raw material information used is shown in Table 1.

Table 1 raw material instruction Polymer A Alkaline soluble polymer, acrylic acid polymer A having carboxyl group prepared in Synthesis Example 1 Polymer B Alkaline soluble polymer, acrylic acid polymer B having carboxyl group prepared in Synthesis Example 2 Polymer C Alkaline soluble polymer, acrylic acid polymer C having carboxyl group prepared in Synthesis Example 3 3EO TMPTA Ethylene unsaturated double bond compound, ethoxylated trihydroxymethylpropane triacrylate, CAS No.: 28961-43-5 Bis-A 10EO DMA Ethylene unsaturated double bond compound, ethoxylated bisphenol A dimethacrylate, CAS No.: 41637-38-1 HABI;BCIM Photopolymerization initiator, imidazole compound, CAS No.: 7189-82-4 TCDM Photopolymerization initiator, imidazole compound, CAS No.: 100486-97-3 EABF Photopolymerization initiator, ketone compound, CAS No.: 90-93-7 IR907 Photopolymerization initiator, ketone compound, CAS No.: 71868-10-5 BDK Photopolymerization initiator, ketone compound, CAS No.: 24650-42-8 Oily yellow Light absorber, dye, CAS number: 3321-10-4 ADMA Light absorber, dye, CAS number: 603-48-5 9PA Light absorber, CAS number: 602-56-2 NPG Light absorber, CAS number: 103-01-5 2-Benzene-2-nitrobenzimidazole Light absorber, CAS number: 583-39-1 CI42040 Light absorber, dye, CAS number: 633-03-4 THF Solvent, Tetrahydrofuran, CAS No.: 109-99-9

The components were mixed according to the ratio of components shown in Table 2 below, and stirred for 1 hour to mix uniformly, thereby obtaining a resin composition. Thereafter, the obtained resin composition was coated on a PET film as a protective film using a Kodaira wire rod, and then the coated resin composition was dried in an oven at 100 ^° C for 24 minutes, and then a PE film as a protective film was covered on the surface of the dried resin composition, thereby obtaining the photoresist films (i.e., composite films) coated with protective films of Examples 1 to 7 and Comparative Examples 1 to 5.

Table 2 Unit: Weight Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Embodiment 5 Embodiment 6 Embodiment 7 Comparison Example 1 Comparison Example 2 Comparison Example 3 Comparison Example 4 Comparison Example 5 Polymer A 200 200 200 200 200 200 Polymer B 222 222 222 222 Polymer C 200 200 3EO TMPTA 5 5 5 5 10 10 5 5 5 5 10 30 Bis-A 10EO DMA 45 30 30 30 30 30 30 30 30 30 46 5 HABI;BCIM 3.2 3.2 2.5 3.2 3.5 1.5 2 5 5.5 5.5 4 1 TCDM 0.2 0.2 EABF 0.03 0.01 0.03 0.02 0.03 0.01 0.5 0.3 0.2 0.4 IR907 0.02 0.2 0.02 BDK 4 3 2.5 Oily yellow 0.5 ADMA 0.1 0.1 0.08 0.1 0.08 0.1 0.05 1 1 1 0.8 0.8 9PA 0.15 0.1 1 0.7 0.5 NPG 0.02 0.01 0.01 0.02 0.01 0.02 0.01 0.02 0.1 2-Benzene-2-nitrobenzimidazole 0.01 0.01 0.01 0.02 0.01 0.01 0.01 0.01 CI42040 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 THF 10 10 10 10 10 10 10 10 10 10 10 10

3.2.3. Photoresist film Test

The properties of the photoresist films and photoresist patterns of Examples 1 to 7 and Comparative Examples 1 to 5 were measured according to the measurement methods described above, and the results are recorded in Table 3 below.

table 3 Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Embodiment 5 Embodiment 6 Embodiment 7 Comparison Example 1 Comparison Example 2 Comparison Example 3 Comparison Example 4 Comparison Example 5 A _405nm /T 0.005 0.005 0.002 0.006 0.004 0.003 0.001 0.009 0.007 0.008 0.012 0.014 A _436nm /T 0.004 0.005 0.001 0.004 0.003 0.002 0.001 0.008 0.006 0.006 0.012 0.013 A _365nm /T 0.009 0.006 0.005 0.010 0.008 0.008 0.004 0.023 0.008 0.007 0.038 0.005 Photoresist film thickness T (micrometer) 250 250 250 250 60 600 500 250 250 250 250 250 |(Upper Width - Lower Width)| (micrometers) ＜5 ＜5 ＜5 ＜5 ＜2 ＜5 ＜5 >20 >20 >20 >20 >20 Photoresist pattern shape rectangle rectangle rectangle rectangle rectangle rectangle rectangle Trapezoid Trapezoid Trapezoid Trapezoid Trapezoid Foot length (MDT*2; microns) 5 7 3 5 3 4 3 25 15 18 30 35 Foot length (MDT*4; microns) 7 9 3 7 5 5 3 >35 >35 >35 >35 >35 Comprehensive evaluation good good good good good good good Poor Poor Poor Poor Poor

As shown in Table 3, the light absorption properties of the photoresist films of Examples 1 to 7 of the present invention satisfy 0＜A _405nm /T≦0.006 and 0＜A _436nm /T≦0.005, so the photoresist pattern formed by the photoresist film after exposure and development can have a rectangular cross-section and a short foot length (less than 10 microns), which means that the photoresist pattern has an excellent cross-sectional profile. In particular, Examples 3 and 7 further show that if the light absorption properties of the photoresist film satisfy 0＜A _405nm /T≦0.002 and 0＜A _436nm /T≦0.001, the foot length of the photoresist pattern is most significantly improved, resulting in the most excellent cross-sectional profile. In comparison, the light absorption properties of the photoresist films of Examples 1 to 5 do not satisfy 0＜A _405nm /T≦0.006 and 0＜A _436nm /T≦0.005. Therefore, the photoresist pattern formed by the photoresist film after exposure and development does not have a rectangular cross-section and has a long foot length, which means that the cross-sectional profile of the photoresist pattern is not good and is not suitable for application in etching or electroplating processes that require high precision.

The above embodiments are only for illustrative purposes to illustrate the principle and efficacy of the present invention and to illustrate the technical features of the present invention, and are not intended to limit the scope of protection of the present invention. Any changes or arrangements that can be easily accomplished by anyone familiar with the present technology without violating the technical principle of the present invention are within the scope of the present invention. Therefore, the scope of protection of the present invention is as listed in the attached patent application scope.

:without.

:without.

:without.

Claims (10)

A photoresist film has a thickness T in micrometers, and when measured by ultraviolet-visible spectroscopy, the photoresist film has an absorbance of A _405nm for light with a wavelength of 405 nanometers and an absorbance of A _436nm for light with a wavelength of 436 nanometers, wherein 0＜A _405nm /T≦0.006 and 0＜A _436nm /T≦0.005, and the thickness T is 60 micrometers to 600 micrometers. The photoresist film as described in claim 1, wherein the photoresist film has an absorbance A _365nm for light of a wavelength of 365 nanometers when measured by UV-visible spectroscopy, wherein 0＜A _365nm /T≦0.010. A photoresist film as described in claim 1 or 2, wherein the UV-visible spectroscopy is performed using a UV-visible spectrophotometer under the following conditions: the photoresist film is placed perpendicular to the direction of the incident light source; a diffraction grating is configured as a spectrometer; the test temperature is 25°C; the test pressure is 1 atmosphere; the analysis mode is absorbance; the scanning wavelength range is 190 nm to 1100 nm; the blank sample is air; the scanning speed is 2200 nm/min; the lamp source switching wavelength from a deuterium lamp to a tungsten filament lamp is 340.8 nm; the sampling interval is 0.2 nm; and the slit width is 2.0 nm. The photoresist film as described in claim 1 or 2 is a negative photoresist film. The photoresist film as claimed in claim 1 or 2, wherein 0＜A _405nm /T≦0.002 and 0＜A _436nm /T≦0.001. The photoresist film as described in claim 1 or 2 comprises: (A) an alkali-soluble polymer; (B) an ethylenically unsaturated double-bond compound; and (C) a photopolymerization initiator. The photoresist film as described in claim 6, wherein the ethylenically unsaturated double bond compound (B) comprises a bifunctional acrylic compound. The photoresist film as described in claim 7, wherein the content of the bifunctional acrylic compound is greater than 60 wt % based on the total weight of the ethylenically unsaturated bibond compound (B). A composite film comprising: A photoresist film as described in any one of claims 1 to 8; and A protective film formed on at least one surface of the photoresist film. The composite film as described in claim 9, wherein the protective film is selected from the following group: polyethylene terephthalate film, polyolefin film and a composite of the foregoing.