A dual-color photolithography bottom anti-reflective coating and preparation method thereof

Abstract

The invention relates to the technical field of photolithography auxiliary chemicals, and discloses a dual-color photolithography bottom anti-reflection coating, which is prepared from the following organic coating solution, wherein the organic coating solution includes at least one film-forming substance containing a dual-color ultraviolet absorbing dye structure, an auxiliary agent and an organic solvent; the dual-color ultraviolet absorbing dye structure is as shown in formula (I); the dual-color photolithography bottom anti-reflection coating has strong absorption of electromagnetic waves with wavelengths of 193nm and 248nm. The invention uses a film-forming substance containing the dual-color ultraviolet absorbing dye structure in a molecular structure, an auxiliary agent and a solvent to form an organic coating solution, and solidifies it through a spin coating process and a hot plate baking process, so that it has strong absorption of electromagnetic waves with wavelengths of 193nm and 248nm, which is manifested as the imaginary part k of the complex refractive index at the two wavelengths reaching more than 0.2, and is suitable for ArF and KrF excimer laser lithography.

Description

Technical Field

[0001] The invention relates to the technical field of optical auxiliary chemicals, in particular to a dual-color photolithography bottom anti-reflection coating and a preparation method thereof. Background Art

[0002] Photolithography is an indispensable processing technology in the manufacture of micro-nano devices such as semiconductors, LCDs, LEDs, MEMS, and microfluidics. Its essence is to prepare the designed pattern on a set of mask plates, and then through a layer called photosensitive resist coating or photoresist (PR) on the base surface of semiconductors, metals, dielectrics, etc., through electromagnetic radiation, electron beam, or ion beam exposure, after development, the pattern on the mask is copied to the substrate surface to form a binary photoresist relief pattern. Subsequently, the photoresist relief pattern is used as a resist, and the substrate surface is selectively doped, etched, or deposited, so as to transfer the pattern on the mask to the substrate.

[0003] Photoresist is usually a photosensitive polymer resin solution, which is usually evenly coated on a flat substrate by rotation, and then heated to remove the solvent to form a thin film of uniform thickness. After being irradiated, the photoresist resin undergoes a chemical reaction, which changes its structure and causes its solubility in the developer to change. The resin in the exposed area or the non-exposed area can be selectively removed through the development process, forming a binary-like relief pattern.

[0004] Photoresists are divided into positive photoresists and negative photoresists. Positive photoresists are difficult to dissolve in the developer before exposure, but the dissolution rate increases hundreds of times after exposure. Under differential exposure conditions, the photoresist in the exposed area will be dissolved by the developer, while the photoresist in the non-exposed area is basically unaffected, thus forming a relief pattern on the substrate that is similar to the mask pattern. Negative photoresists are just the opposite. The exposed area is retained, while the non-exposed area is washed away by the developer, forming a relief pattern on the substrate that is the inverse of the pattern on the mask.

[0005] The photolithography effect is directly affected by imaging optics and photochemical reactions, and is also related to the propagation of light in the medium. The optical properties of an isotropic material can be simply described by its complex refractive index (n+ik). Here n is the refractive index, and the imaginary part k is a constant related to the material and its light absorption (hereinafter referred to as the absorption parameter k or k value). When light enters the interface of one substance from another, it will be reflected and refracted. The ratio of the intensity of the reflected light to the intensity of the incident light is called the power reflectivity or simply the reflectivity R. Compared with the interface between air / organic matter or organic matter (k=0-0.6), semiconductor or metal substrates have strong absorption (k=1-7), so their surfaces have high reflectivity. Because light will be strongly reflected at the interface between the photoresist PR and the substrate during the photolithography process, the reflected light and the incident light will interfere in the PR layer, causing the light intensity inside the photoresist to change periodically. If the reflection is not controlled, the photoresist pattern will have standing wave-like sidewalls, and the optimal exposure energy required for the photoresist will fluctuate periodically with the film thickness, seriously affecting the control of the photolithography resolution and critical dimension (CD). If a substrate with a surface structure is used, the mirror reflection generated by the inclined surface may also cause concave defects in the adjacent photoresist pattern.

[0006] The thin film interference effect inside the PR can be controlled by a top anti-reflective coating (TARC) and / or a bottom anti-reflective coating (BARC), where TARC is an auxiliary thin layer applied on top of the photoresist, while BARC is an auxiliary thin layer applied between the photoresist and the substrate.

[0007] Assuming that PR is medium 1 and the substrate SUB is medium 2, then using BARC is equivalent to inserting a layer of medium 3 called BARC between the two media, so that the original PR / SUB interface is replaced by a PR / BARC interface, a strongly absorbing BARC layer, and a BARC / SUB interface. When a beam of light (B0) is incident on the PR / BARC interface, a beam of transmitted light (B1) and a beam of reflected light (B2) will be formed. After the transmitted light beam (B1) enters the BARC layer, it will be reflected back and forth between the BARC / SUB interface and the PR / BARC interface multiple times. During each reflection, part of the light will be transmitted from the BARC layer and overflow into the PR layer. The light beam (B3) formed by the merger of the multiple overflowing light beams will merge with the light beam B2 to form the total reflected light beam. The intensity of the total reflected light beam divided by the incident light intensity is the equivalent reflectivity R of the PR / BARC / SUB composite layer. eff For normal incidence, the equivalent amplitude reflection coefficient or simply reflection coefficient (ρeff) of the PR / BARC / SUB composite layer can be expressed as:

[0008]

[0009] Reff =P eff P eff *

[0010] Above 12 is the reflection coefficient of PR / BARC, ρ 23 is the reflection coefficient of BARC and substrate SUB, n2+ik2 is the complex refractive index of BARC, t2 is the film thickness of BARC layer, is the attenuation factor of light due to absorption when traveling between two interfaces. It is the phase factor caused by the phase difference between the two interfaces when the light travels back and forth. The denominator is the correction term caused by the multiple round-trip reflections of the light in the BARC layer. The equivalent reflectivity Reff is the square of the modulus of the reflection coefficient ρeff.

[0011] When the BARC film thickness t2 is zero, the correction factors of the above formulas are all 1, and the equivalent reflection coefficient ρeff and the reflection coefficient ρ of PR / SUB are 13 The same is equivalent to the absence of the BARC layer. When the BARC film thickness t2 gradually increases from 0, an attenuation factor is obtained due to the round-trip absorption in the BARC layer. When the film thickness gradually increases from zero to a certain value, the phase difference between beam 3 and beam 2 will be exactly 180 degrees, and the two beams will interfere destructively, causing the reflected light intensity to form a minimum. On this basis, the reflected light intensity will reach a minimum every time the film thickness increases by half a wavelength (λ / 2n2). For convenience, the film thicknesses corresponding to the various minima that appear successively starting from zero film thickness are usually called the first, second, and third minimum film thicknesses of BARC. It can also be found from the above formula that when BARC approaches infinity (more than 5 penetration depths), each exponential factor returns to zero, and the reflection coefficient converges to PR / BARC reflection coefficient ρ 12 Therefore, it is not the case that the greater the BARC absorption, the better, because increasing the k value of BARC will increase the reflection coefficient ρ 12 For BARCs that require thick film filling, the k value cannot be chosen to be too large.

[0012] The minimum values ​​of the reflected light intensity at the above film thicknesses do not necessarily correspond to a reflectivity of zero. By selecting the absorption parameter (k2) and film thickness (t2) of the BARC, the intensity of the light beam 3 at a certain minimum film thickness can be attenuated to be exactly equal to the intensity of the light beam 2, so that the two light beams interfere completely destructively, thereby achieving an equivalent reflection coefficient of zero for the BARC stack. The above goals can be achieved by calculating the optimal complex refractive index (n, k) and film thickness (t2) of the BARC layer through mathematical methods based on the optical parameters of the photoresist PR and the substrate SUB.

[0013] BARC can be inorganic BARC or organic BARC. The former can be prepared by CVD, which is characterized by a wide absorption peak and easy preparation of a conformal thin layer, but the disadvantage is that it is difficult to remove after the process and must be retained in the device. Inorganic BARC was also widely used in the early days, but later gradually gave way to organic BARC. The organic BARC layer can be applied by spin coating, and after thermal curing, it is no longer soluble in organic solvents and developers, and can be removed by oxygen plasma after the process. In the photolithography process, after the PR / BARC double-layer film is exposed and developed, the BARC layer at the bottom of the PR is exposed. The PR pattern obtained after development needs to be used as a resist, and the BARC layer is opened by plasma etching to expose the bottom substrate (except for developable BARC). In order to avoid losing too much PR layer during the BARC film opening etching process, the BARC layer is usually less than 150nm, about 5-10% of the PR thickness, and has a higher etching rate (selectivity is about 1.4-2.5 times).

[0014] The first minimum film thickness of BARC is generally between 30 and 80 nm. If it is necessary to prepare a BARC with the first minimum film thickness, the required dye must have strong absorption, that is, the absorption parameter k is generally required to be between 0.4 and 0.7. For a BARC with a film thickness of FT to 30-80 nm, the required dye must have strong absorption, that is, the molar extinction coefficient to molecular weight ratio (e / M) is 250-400. In fact, only a few organic dyes can meet this requirement. Anthracene derivative KrF dye and benzene derivative ArF dye can meet the above requirements, but it is difficult to find near-ultraviolet dyes that meet such requirements. The anthracene derivatives in the above dyes are condensed ring structures, and their presence will significantly reduce the plasma etching rate of BARC. Dyes with lower absorption (e / M=100-250) are usually used for the second and third minimum film thickness BARC, that is, the filling BARC formula of FT to 100-200 nm.

[0015] Over the past few decades, with the continuous demand for increasing IC integration density, the resolution of lithography has gradually changed from micrometer level to nanometer level to the currently developed angstrom level. The wavelength of lithography has changed from the initial G-line (436nm), I-line (365nm), KrF (248nm), ArF (193nm), immersion ArF (193nm), to the most advanced EUV (13.5nm). The numerical aperture (NA) of the optical system has increased from 0.2-0.4 in G-line lithography in the 1960s to 0.9-1.35 in immersion ArF lithography today. The illumination mode has also changed from parallel light illumination, off-axis illumination, to dipole illumination. In off-axis illumination and high NA lithography, a single-layer BARC is no longer sufficient to completely control the reflection of the substrate. Double-layer or multi-layer BARC has begun to be used in the lithography process, and gradient BARC with better extinction effect has also begun to appear. Dyes with relatively low absorption parameters (e / M=100-250) can therefore find more applications in multi-layer BARC systems.

[0016] As mentioned above, the absorption parameters of the dye used in BARC need to be highly matched with the lithography wavelength, so each lithography technology must match the corresponding BARC. In addition, different PRs sometimes have special requirements for BARC, which leads to a high degree of fragmentation in the BARC product market.

[0017] The strong absorption of organic UV dyes comes from the electronic transitions between the narrow electronic energy levels of the molecular structure, so the absorption peak width is very small, especially for DUV and EUV dyes. It is difficult for a single organic dye structure to have strong absorption capabilities at the common lithography wavelengths of 365nm, 248nm, and 193nm at the same time. Although a combination of multiple dyes can make the BARC coating have considerable absorption in the above bands, it is difficult to ensure that the coating has a corresponding etching selectivity due to the limitation of the amount of dye added. Therefore, it is necessary to develop two-color or multi-color ultraviolet organic dyes and broad-spectrum bottom anti-reflective coatings that can work at two or more wavelengths, thereby reducing the types of products and reducing production costs. Summary of the invention

[0018] In view of the shortcomings of the prior art, the present invention provides a dual-color lithography bottom anti-reflection coating which has a strong absorption effect on 193nm and 248nm electromagnetic waves and a faster etching speed and is suitable for ArF and KrF lithography.

[0019] To achieve the above objectives and other related objectives, the present invention is achieved through the following technical solutions.

[0020] The first aspect of the present invention is to provide a dual-color photolithography bottom anti-reflection coating, wherein the dual-color photolithography bottom anti-reflection coating is prepared from the following organic coating solution, wherein the organic coating solution is formed by a film-forming substance containing a dual-color ultraviolet absorbing dye structure in the molecular structure, an auxiliary agent and a solvent; the dual-color ultraviolet absorbing dye structure is shown in formula (I):

[0021]

[0022] Wherein, R1 is selected from any one of halogen, hydroxyl, and C1-C10 alkoxy; R2 is selected from any one of C1-C10 alkoxy and hydroxyl;

[0023] The imaginary part k value of the complex refractive index of the dual-color photolithography bottom anti-reflection coating for electromagnetic waves with wavelengths of 193nm and 248nm is not less than 0.2.

[0024] In some embodiments of the present invention, R1 is selected from chloro, bromo, hydroxy, methoxy or ethoxy.

[0025] In some embodiments of the present invention, the film-forming material comprising a dual-color ultraviolet absorbing dye structure of the present invention is formed by a substructure of the dual-color ultraviolet absorbing dye bonded to a polymer via a covalent bond; the substructure of the dual-color ultraviolet absorbing dye structure is as shown in any one of the following formulas (II), (III), and (IV):

[0026]

[0027] Wherein, X is selected from halogen or hydroxyl.

[0028] In some embodiments of the present invention, the film-forming substance containing the dual-color ultraviolet absorbing dye structure comprises a polymer obtained by polymerization of one or more organic monomers, and the organic monomers contain at least the dual-color ultraviolet absorbing dye structure.

[0029] In some embodiments of the present invention, the film-forming substance containing a two-color ultraviolet absorbing dye structure includes at least one polymer grafted with small molecules, and the small molecules contain the two-color ultraviolet absorbing dye structure; the polymer is selected from one or more of vinyl polymers, acrylic resins, polyether resins, polyester resins, polyamides, epoxy resins, phenolic resins, phenoxy resins, cellulose, and aldehyde-ketone resins.

[0030] In some embodiments of the present invention, the film-forming substance containing a dual-color ultraviolet absorbing dye structure is a film-forming resin and / or a cross-linking agent.

[0031] In some embodiments of the present invention, the auxiliary agent includes one or more of a cross-linking agent, a heat-activated catalyst, a leveling agent, and a tackifier.

[0032] In some embodiments of the present invention, the solvent is selected from one or more of propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, 2-hydroxypropyl acetate, 3-methoxypropionic acid methyl ester, 3-ethoxypropionic acid ethyl ester, cyclohexanone, cyclopentanone, phenethyl ether, ethyl acetoacetate, and xylene.

[0033] In some embodiments of the present invention, the weight ratio of the film-forming substance with a dual-color ultraviolet absorbing dye structure, the cross-linking agent, and the thermally activated catalyst in the composition is (100): (3-20): (0.1-5).

[0034] In some embodiments of the present invention, the weight ratio of the solvent to the remaining components in the organic coating solution is 100:(1-10).

[0035] In some embodiments of the present invention, the crosslinking agent is selected from amino resins, preferably tetrabutoxymethyl urea, hexamethoxymethyl melamine, tetramethoxymethyl ethyl urea, tetrabutoxymethyl ethyl urea, or one or more oligomers with a molecular weight of 500-2000 Daltons formed by one or more of the above amino resins.

[0036] In some embodiments of the present invention, the thermally activated catalyst is selected from thermal acid generators.

[0037] A second aspect of the present invention provides a method for preparing the above-mentioned dual-color photolithography bottom anti-reflective coating, comprising the following steps:

[0038] (1) taking a film-forming substance containing a dual-color ultraviolet absorbing dye structure and an auxiliary agent according to a weight ratio, mixing them, and adding a solvent to form an organic coating solution;

[0039] (2) Spin coating the organic coating solution on the substrate surface, and bake and solidify it to obtain a dual-color photolithography bottom anti-reflective coating.

[0040] The third aspect of the present invention provides the use of the above two-color ultraviolet absorbing dye structure or the above film-forming material containing the two-color ultraviolet absorbing dye structure in preparing a lithography anti-reflection coating commonly used in ArF and KrF excimer laser lithography.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The present invention adjusts the benzene ring structure, selects an electron-withdrawing carbonyl [-C(O)-] or ester [-C(O)-O-] group to replace the benzene structure, and adjusts the ultraviolet absorption spectrum by selecting an electron-rich substituent connected to the para position. Experiments have found that substituents with p-lone pairs of electrons, including chlorine, bromine, hydroxyl, and alkoxy, can make these dyes have a strong absorption capacity for electromagnetic waves at wavelengths of 193nm and 248nm, that is, the molar extinction coefficient / molecular weight ratio (ε / M) is at least greater than 150. The resin containing the two-color ultraviolet absorption dye structure is used to prepare a bottom anti-reflection coating. The imaginary part k value of the complex refractive index of the obtained bottom anti-reflection coating for electromagnetic waves of 193nm and 248nm wavelengths is not less than 0.2, and can be simultaneously applicable to ArF and KrF excimer laser lithography.

[0043] 2. The film-forming substance containing a two-color ultraviolet absorbing dye structure of the present invention is formed by bonding the substructure of the two-color ultraviolet absorbing dye to a polymer through a covalent bond. The preparation method mainly includes: (1) polymerizing at least one substance containing the two-color ultraviolet absorbing dye structure with an organic monomer; (2) grafting a small molecule containing the two-color ultraviolet absorbing dye structure onto a known polymer; and then using the film-forming substance containing the two-color ultraviolet absorbing dye structure as a film-forming substance, an auxiliary agent, and an organic solvent to form a composition, and adopting a spin coating process and a curing process to prepare a two-color lithography bottom anti-reflective coating, thereby greatly improving the content and distribution uniformity of the two-color ultraviolet absorbing dye structure in the coating.

[0044] 3. The dual-color photolithography bottom anti-reflective coating provided by the present invention is a thermal curing formula, which can adapt to the hot plate and oven processes that are widely used in micro-processing processes. The thermally activated catalyst in the formula is activated by heating, so that the active groups in the cross-linking agent react with the film-forming resin to form a uniform coating that is insoluble, non-swelling, and non-eluting. The preparation is simple, the cost is low, the etching rate is high, and it is conducive to industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 Schematic diagram of the molecular structure of different dual-color ultraviolet absorbing dye structures and contrasting monochromatic ultraviolet absorbing dye structures.

[0046] Figure 2 This is a comparison chart of the refractive index change trends of five lithography bottom anti-reflection coatings prepared with p-bromobenzoic acid, p-fluorobenzoic acid, p-chlorobenzoic acid, p-iodobenzoic acid and p-methoxybenzoic acid as dual-color ultraviolet absorption dye structures at different wavelengths.

[0047] Figure 3 This is a comparison chart of the absorption parameter change trends of five lithography bottom anti-reflection coatings prepared with p-bromobenzoic acid, p-fluorobenzoic acid, p-chlorobenzoic acid, p-iodobenzoic acid and p-methoxybenzoic acid as dual-color ultraviolet absorption dye structures at different wavelengths.

[0048] Figure 4 This is a comparison chart of the absorption parameters and refractive index change trends of two types of lithography bottom anti-reflection coatings prepared with anthracenecarboxylic acid and benzoic acid as monochromatic ultraviolet absorption dyes at different wavelengths.

[0049] Figure 5 The trend diagram of the equivalent interface reflectance of two dual-color photolithography bottom anti-reflection coatings formed with p-chlorobenzoic acid and p-bromobenzoic acid as dual-color ultraviolet absorption dye structures under 193nm wavelength light varies with film thickness. The curve in the figure is based on the setting of the complex refractive index of the photoresist to 1.72+0.02i and the substrate to crystalline silicon.

[0050] Figure 6 The figure is a trend chart of the change of equivalent interface reflectance with film thickness of two-color photolithography bottom anti-reflection coatings with two film thicknesses formed by two-color ultraviolet absorption dye structures of p-chlorobenzoic acid and p-bromobenzoic acid under 248nm wavelength light. The curve in the figure is based on the setting of the complex refractive index of the photoresist to 1.72+0.02i and the substrate to crystalline silicon. DETAILED DESCRIPTION

[0051] In order to make the purpose of the invention, technical solutions and beneficial technical effects of the present invention clearer, the present invention is further described in detail below in conjunction with embodiments. People familiar with this technology can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0052] The first aspect of the present invention is to provide a dual-color photolithography bottom anti-reflection coating, wherein the dual-color photolithography bottom anti-reflection coating is prepared from the following organic coating solution, wherein the organic coating solution is formed by a film-forming substance containing a dual-color ultraviolet absorbing dye structure in the molecular structure, an auxiliary agent and a solvent; the dual-color ultraviolet absorbing dye structure is shown in formula (I):

[0053]

[0054] Among them, R1 is selected from any one of halogen, hydroxyl, C1~C10 alkoxy; R2 is selected from any one of C1~C10 alkoxy and hydroxyl; the imaginary part k value of the complex refractive index of the two-color lithography bottom anti-reflection coating for 193nm and 248nm wavelength electromagnetic waves is not less than 0.2.

[0055] The structure of the dual-color ultraviolet absorbing dye of the present invention comprises a benzene ring structure, and by selecting electron-deficient and electron-rich substituent groups of different structures and mutually para-substituted groups, it has strong absorption of electromagnetic waves with wavelengths of 193nm and 248nm, that is, the molar extinction coefficient / molecular weight ratio (ε / M) is at least greater than 150. Preferably, the electron-deficient substituent is an acyl group [-C(O)-R] or an acyloxy group [-C(O)-OR], that is, R is hydrogen or a C1-C10 alkyl group. Preferably, the electron-rich substituent is a para-substituted substituent with a p-lone pair of electrons, including halogen, chlorine, bromine, iodine, hydroxyl, and C1-C10 alkoxy. In some embodiments of the present invention, R1 in formula (I) is selected from chlorine, bromine, hydroxyl, methoxy or ethoxy, and the k value of the complex refractive index of these dye structures at a wavelength of 248nm is larger.

[0056] In some embodiments of the present invention, the film-forming material comprising a dual-color ultraviolet absorbing dye structure of the present invention is formed by a substructure of the dual-color ultraviolet absorbing dye bonded to a polymer via a covalent bond; the substructure of the dual-color ultraviolet absorbing dye structure is as shown in any one of the following formulas (II), (III), and (IV):

[0057]

[0058] Wherein, X is selected from halogen or hydroxyl. In some specific embodiments of the present invention, the substructure of the dual-color ultraviolet absorbing dye structure is connected to other carbon atoms of the polymer in the form of one or two non-conjugated covalent bonds through the oxygen atom or carbon atom in the formula (II), (III), (IV). In some embodiments of the present invention, the film-forming substance containing the dual-color ultraviolet absorbing dye structure is used as a film-forming resin and / or a cross-linking agent in the coating component, that is, the main material in the coating component.

[0059] Although the film-forming substance containing the substructure of the dual-color ultraviolet absorbing dye described in the present invention (as the main material of the photolithography anti-reflective coating) can be any macromolecular structure with irregular structure, for simplicity and convenience, in some embodiments of the present invention, the film-forming substance containing the dual-color ultraviolet absorbing dye structure described in the present invention includes a polymer obtained by polymerization of one or more organic monomers, at least one of which contains the dual-color ultraviolet absorbing dye structure; the synthesis method of the film-forming substance containing the dual-color ultraviolet absorbing dye structure is a polymer obtained by polymerization of one or more organic monomers, at least one of which (can be a film-forming resin monomer or a cross-linking agent monomer) contains the dual-color ultraviolet absorbing dye structure. The polymerization can be carried out in a variety of ways, including but not limited to addition polymerization or condensation polymerization. In some specific embodiments of the present invention, the synthesis method of the film-forming substance containing the dual-color ultraviolet absorbing dye structure is obtained by copolymerizing an acrylate monomer or a methacrylate monomer containing the dual-color ultraviolet dye structure with at least one of hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate and N-hydroxymethyl acrylamide.

[0060] In some other embodiments of the present invention, at least one polymer grafted with a small molecule is included, and the small molecule contains the dual-color ultraviolet absorbing dye structure. The synthesis method of the film-forming material containing the dual-color ultraviolet absorbing dye structure is to graft the small molecule containing the dual-color ultraviolet dye structure onto the film-forming resin polymer by a chemical method. The film-forming resin polymer includes but is not limited to ethylene polymer, (methacrylic acid) acrylic resin, polyether resin, polyester resin, polyamide, epoxy resin, phenolic resin, phenoxy resin, cellulose, aldehyde ketone resin. In some specific embodiments of the present invention, the synthesis method of the film-forming material containing the dual-color ultraviolet absorbing dye structure is to react the small molecule containing the dual-color ultraviolet dye structure with active hydroxyl and graft it onto a polymer having an epoxy side group; the active hydroxyl includes but is not limited to phenol and carboxylic acid; the polymer having an epoxy side group includes but is not limited to an acrylic polymer or a methacrylic polymer. In some specific embodiments of the present invention, the acrylic polymer or the methacrylic polymer contains a glycidyl acrylate repeating unit or a glycidyl methacrylate repeating unit.

[0061] The following examples illustrate the structure of a film-forming substance containing a two-color ultraviolet absorbing dye structure (for example, a film-forming resin or a cross-linking agent structure containing a two-color ultraviolet absorbing dye structure). It should be noted that these structures do not mean that the structure of the film-forming substance containing a two-color ultraviolet absorbing dye structure described in the present invention is limited to these structures. They are only listed here as a specific description of the present invention.

[0062] Preferably, the film-forming substance (film-forming resin) containing a dual-color ultraviolet absorbing dye structure includes any one of the following repeating units of a branched structure formed by bonding the dual-color ultraviolet absorbing dye and the following repeating monomers connected to the main chain via an ester group or a carbonyl group:

[0063]

[0064] Among them, R1 is selected from any one of halogen, hydroxyl, and low-carbon alkoxy; R2 is selected from any one of divalent alkyl and alkoxy; R3 is selected from hydrogen or methyl, and R4 is selected from any one of C1-C10 alkyl; preferably, R1 is selected from chlorine, bromine, methoxy or ethoxy; R2 is selected from ethane-1,2-diyl (ethylene), propane-1,2-diyl, propane-1,3-diyl (propylene) or 2-hydroxypropane-1,3-diyl (2-hydroxypropylpropylene, -CH2CH(OH)CH2-); R3 is selected from hydrogen or methyl; R4 is selected from methyl.

[0065] The film-forming substance (film-forming resin) containing a dual-color ultraviolet absorbing dye structure may contain two or more repeating units, and preferably, further comprises any one or two of the following branched repeating units:

[0066]

[0067] Wherein, R4 is selected from hydrogen or methyl.

[0068] The repeating unit contains a large number of carbonyl groups and hydroxyl groups, which can improve the plasma etching rate of the bottom anti-reflective coating and provide suitable cross-linkable functional groups.

[0069] Preferably, the film-forming substance (film-forming resin) containing a two-color ultraviolet absorbing dye structure includes a binary or ternary copolymer formed by bonding the two-color ultraviolet absorbing dye, including any one of the following structures, the following structure only shows the head-to-tail connection of monomers, and any head-to-tail and tail-to-tail connection of monomers is included in the protection scope of the present invention, which will not be repeated hereafter:

[0070]

[0071]

[0072] Wherein, l, m are natural numbers; R1 is selected from any one of halogen, hydroxyl, and low-carbon alkoxy; R2 is selected from any one of C1-C10 divalent alkyl and alkoxy; R3 and R4 are each independently selected from any one of hydrogen or low-carbon alkyl; R5 is selected from any one of hydrogen, low-carbon alkyl, and low-carbon alkoxy; preferably, R1 is selected from any one of chlorine, bromine, hydroxyl, and methoxy; R2 is selected from any one of ethane-1,2-diyl alkyl and 2-hydroxypropane-1,3-diyl; R3 and R4 are each independently selected from hydrogen or methyl; R5 is selected from hydrogen, methyl, or methoxy. The above-mentioned terpolymer film-forming resin includes two functional groups, hydroxyl and N-methylol, which can react with each other and can be cross-linked and cured in the presence of a catalyst without other cross-linking agents.

[0073]

[0074]

[0075] Wherein, l, m, n are natural numbers, l accounts for 30-90% of (l+m+n), m accounts for 0-50% of (l+m+n), and n accounts for 5-10% of (l+m+n); R1 is selected from any one of halogen, hydroxyl, and low-carbon alkoxy; R2 is selected from any one of C1-C10 divalent alkyl and alkoxy; R3, R4 and R6 are selected from any one of hydrogen or low-carbon alkyl; R5 is selected from any one of hydrogen, low-carbon alkyl, and low-carbon alkoxy Any one; preferably, R1 is selected from any one of chlorine, bromine, hydroxyl, methoxy; R2 is selected from any one of ethane-1,2-diyl (ethylene), propane-1,2-diyl, propane-1,3-diyl (propylene) or 2-hydroxypropane-1,3-diyl (2-hydroxypropylpropene, -CH2CH(OH)CH2-); R3, R4 and R6 are each independently selected from hydrogen or methyl; R5 is selected from hydrogen, methyl or methoxy.

[0076] The above structure is a part of the example of the film-forming material comprising the dual-color ultraviolet absorbing dye structure of the present invention, i.e., the dual-color ultraviolet absorbing dye structure is connected to form a polymer side chain. In fact, the dual-color ultraviolet absorbing dye structure of the present invention can also become a part of the film-forming resin main chain through multiple atomic bonding in the molecule.

[0077] Preferably, the backbone of the film-forming resin has an ether ester alcohol structure, and they have higher etch rates in various plasma chemistries. Preferred synthesis methods include divalent acids, including carboxylic acids, acidic phenols, or phenols prepared by reaction with diglycidyl ethers / esters.

[0078] Preferably, the divalent acid structure is:

[0079]

[0080] Wherein, R7 is selected from aliphatic divalent alkyl containing low carbon or low carbon oxygen; preferably, R7 is selected from ethylene, 1,3-propylene, 1,4-butene, bis(2-ylethyl) ether (3-oxa-1,5-pentene, -CH2CH2OCH2CH2-);

[0081] Preferably, the structure of the diglycidyl ether or ester is:

[0082]

[0083] Among them, R8 is selected from C1~C10 aliphatic divalent carbonyl groups, preferably, R8 is selected from ethylene, propylene, butylene, 2,2-dimethylpropylene (-CH2C(CH3)2CH2-); R9 is selected from C1~C10 aliphatic divalent carbon groups; preferably, R9 is selected from methylene, vinyl, 1,3-propenyl, etc.

[0084] Preferably, the film-forming substance containing a dual-color ultraviolet absorbing dye structure may have any of the following structures:

[0085]

[0086] Wherein, m and n are positive integers, and m+n is in the range of 10 to 1000; R7 is selected from aliphatic divalent alkyl groups containing low carbon or low carbon oxygen; and R8 is selected from C1 to C10 aliphatic divalent carbonoxy groups.

[0087] In the above example, the bi-color UV absorbing dye is covalently bonded to the backbone of the polymer (film-forming resin) by covalently bonding to the alkoxy or carbonyl group containing a pi-electron pair. In other words, the dye is attached to the backbone through two different atoms in the dye structure, making it part of the backbone.

[0088] The dual-color photolithography bottom anti-reflection coating of the present invention is a heat-curing formula, which can adapt to hot plate and oven processes widely used in micro-fabrication processes. In addition to the film-forming substance (film-forming substance) of the dual-color ultraviolet absorbing dye structure, the composition for preparing the dual-color photolithography bottom anti-reflection coating also includes an auxiliary agent and a solvent.

[0089] In some embodiments of the present invention, the auxiliary agent includes one or more of a cross-linking agent, a heat-activated catalyst, a leveling agent, and a tackifier.

[0090] In some embodiments of the present invention, the weight ratio of the film-forming substance with a dual-color ultraviolet absorbing dye structure, the cross-linking agent, and the thermally activated catalyst in the organic coating solution is 100: (3-20): (0.1-5).

[0091] In some embodiments of the present invention, the weight ratio of the solvent to the remaining components in the organic coating solution is 100:(1-10).

[0092] Preferably, the crosslinking agent is selected from amino resins widely used in the coating industry, including various types of butoxylated, ethoxylated, propoxylated, isopropoxylated or methoxylated urea-formaldehyde resins, melamine resins, benzene melamine resins, urea resins, etc., preferably including tetrabutoxymethyl urea, hexamethoxymethyl melamine (HMMM), tetramethoxymethyl ethyl urea, tetrabutoxymethyl ethyl urea, or one or more oligomers formed by one or more of the above amino resins with a molecular weight of 500-2000 Daltons. If the aforementioned self-crosslinking film-forming resin containing both hydroxyl and N-hydroxymethyl propionyl groups is used, no or less crosslinking agent may be added.

[0093] In the present invention, the thermally activated catalyst is selected from thermal acid generator (TAG), also referred to as hidden acid catalyst or blocked acid catalyst. These catalysts are stable at room temperature, but can discharge the acid such as phosphoric acid, sulfonic acid or stronger organic strong acid during heating, and promote the cross-linking reaction between the functional groups such as N-methylol, N-methoxymethyl or N-ethoxymethyl, N-propoxymethyl, N-isopropoxymethyl, N-butoxymethyl and the active radical hydroxyl in the film-forming resin. Specifically, the thermal acid generator is the closed alkyl alkyl acid (comprising benzenesulfonic acid, benzene disulfonic acid, naphthalenesulfonic acid, naphthalene disulfonic acid, anthracenesulfonic acid) containing 0-50 carbon atom such as ammonium salt, sulfonium salt, iodine salt or oxime ester, trifluoromethanesulfonic acid, nonafluorobutanesulfonic acid, bis(trifluoromethyl)sulfonyl imide, tris(trifluoromethylsulfonyl) methane, tetrakis(pentafluorophenyl)boric acid etc. Within the temperature range of 120-250°C, the catalyst is activated, causing the active groups in the cross-linking agent to react with the film-forming resin to form a uniform coating that does not dissolve, swell or elute in common photoresist solvents such as propylene glycol propylene ether, propylene glycol methyl ether, propylene glycol methyl ether, and propylene glycol monomethyl ether.

[0094] In the present invention, the solvent is selected from a single or mixture of low toxic and environmentally friendly solvents acceptable to the micro-processing industry. These solvents include propylene glycol monomethyl ether (PGMEA or PMA), propylene glycol monomethyl ether (PGME or PM), propylene glycol monopropyl ether (PnP), propylene glycol monobutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, propylene glycol dibutyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monoethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol diethyl ether, dipropylene glycol dibutyl ether, dipropylene glycol monomethyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate. 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate, 4-methyl-4-methoxypentyl acetate, 2-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 2-ethoxybutyl acetate, 3-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 4-butoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 2-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 2-ethoxybutyl acetate, 3-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 4-butoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxybutyl acetate, 2-ethoxybutyl acetate, 3-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 4-butoxybutyl acetate, 2-Hydroxypropyl ester, 3-methoxypropyl ester, 3-methoxypropyl ester, 3-methoxypropyl ester, 3-methoxypropyl ester, 3-methoxypropyl ester, 3-methoxypropyl ester, 3-ethoxypropyl ester, 3-ethoxypropyl ester, 3-prop ... Propyl ester, 3-propoxyethyl acetate, 3-propoxyethyl acetate, hydroxyethyl acetate, 2-hydroxy 3-methylbutyric acid methyl ester, ethyl formate, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, isoamyl acetate, isobutyl acetate (IBIB), dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, ethyl benzoate, anisole, phenethyl ether, dihexyl ether, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl fumarate, γ-butyrolactone (GBL), xylene.

[0095] Preferably, the solvent is selected from commonly used photoresist solvents, including propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether (PnP), propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate (PMA or PGMEA), 2-hydroxypropyl ethyl ester (ethyl lactate or EL), methyl 3-methoxypropionate (MMP), ethyl 3-ethoxypropionate (EEP), cyclohexanone, cyclopentanone, phenethyl ether, ethyl acetoacetate, xylene, etc.

[0096] The imaginary part k value of the complex refractive index of the dual-color photolithography bottom anti-reflection coating for electromagnetic waves with wavelengths of 193nm and 248nm is not less than 0.2, and it can be applied to ArF and KrF excimer laser lithography at the same time. The resin in the dual-color photolithography bottom anti-reflection coating is highly cross-linked, and has no swelling, no dissolution, and no elution in alcohol, ester, ether, and ketone organic solvents.

[0097] The second aspect of the present invention is to provide a method for preparing a bottom anti-reflective coating for dual-color lithography, comprising the following steps:

[0098] (1) taking a film-forming substance containing a dual-color ultraviolet absorbing dye structure and an auxiliary agent according to a weight ratio, mixing them, and adding a solvent to form an organic coating solution;

[0099] (2) Spin coating the organic coating solution on the substrate surface, and bake and solidify it to obtain a dual-color photolithography bottom anti-reflective coating.

[0100] Preferably, the rotation speed of the spin coating is 1000-2000 rpm, and can be 1000-1200 rpm, 1200-1400 rpm, 1400-1600 rpm, 1600-1800 rpm or 1800-2000 rpm, and more preferably 1500 rpm.

[0101] Preferably, the baking temperature is 150-250°C, which can be 150-160°C, 160-170°C, 170-180°C, 180-190°C, 190-200°C, 200-210°C, 210-220°C, 220-230°C, 230-240°C or 240-250°C, more preferably 200°C; the baking time is 60-120s, which can be 60-70s, 70-80s, 80-90s, 90-100s, 100-110s, 110-120s, more preferably 60s.

[0102] In some specific embodiments of the present invention, the solid content of the organic coating solution is adjusted to 2wt% to 10wt%, which can be 2wt% to 3wt%, 3wt% to 4wt%, 4wt% to 5wt%, 5wt% to 6wt%, 6wt% to 7wt%, 7wt% to 8wt%, 8wt% to 9wt% or 9wt% to 10wt%, so as to obtain a bottom anti-reflective coating with a film thickness of 30-200nm under the above-mentioned preferred spin coating conditions.

[0103] The third aspect of the present invention provides the use of the above two-color ultraviolet absorbing dye structure or the above film-forming material containing the two-color ultraviolet absorbing dye structure in preparing a lithography anti-reflection coating commonly used in ArF and KrF excimer laser lithography.

[0104] The dual-color ultraviolet absorbing dye structure of the present invention has strong absorption of electromagnetic waves with wavelengths of 193nm and 248nm, so it can be applied to the preparation of a photolithography anti-reflection coating commonly used in ArF and KrF excimer laser lithography; a film-forming substance containing the dual-color ultraviolet absorbing dye structure is used as the main material of the photolithography anti-reflection coating, and an organic coating solution is formed with an auxiliary agent and a solvent, and the photolithography anti-reflection coating is obtained through glue coating, solvent removal, and thermal curing. The obtained photolithography anti-reflection coating is suitable for both ArF and KrF excimer laser lithography.

[0105] The present invention is further described below by way of examples, but the scope of the present invention is not limited thereto.

[0106] When the embodiment gives a numerical range, it should be understood that, unless otherwise specified in the present invention, the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. If specific conditions are not specified in the embodiment, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for all reagents or instruments, they are conventional products that can be purchased commercially. In addition to the specific methods, equipment, and materials used in the embodiments, according to the grasp of the prior art by those skilled in the art and the record of the present invention, any method, equipment, and material of the prior art similar or equivalent to the method, equipment, and material in the embodiments of the present invention can also be used to realize the present invention.

[0107] Example 1

[0108] This embodiment provides another method for preparing epoxy reactive resin GMA100 (i.e. polyglycidyl methacrylate), comprising the following steps:

[0109] Take a 3L three-necked glass round-bottom flask equipped with a mechanical stirrer, condenser and dropping funnel. Add 500g of glycidyl methacrylate and 4.5g of AIBN mixture to the flask, stir to mix and dissolve all components, and then transfer the mixture to a clean reagent bottle for later use. Add 1045g of cyclohexanone to the reactor, stir, heat to 80°C in a water bath, add 90g of the above monomer and initiator mixture to the reactor, and use a dropping funnel to evenly add the remaining mixture to the reactor within 2h. After adding all the monomer mixture, continue to react for half an hour. Then heat to 100°C, pre-dissolve 0.5g of AIBN in 4.5g of cyclohexanone to prepare an initiator solution, add the initiator solution to the reactor, and continue to react for half an hour. After the reaction is completed, cool to room temperature to obtain a GMA100 resin solution with a solid content of 30wt%.

[0110] Example 2

[0111] This embodiment provides a method for preparing epoxy reaction resin GMA50HPA50, i.e. poly(glycidyl methacrylate 50%-co-2-hydroxypropyl acrylate 50%), comprising the following steps:

[0112] Take a 3L three-necked glass round-bottom flask equipped with a mechanical stirrer, a condenser and a dropping funnel. Add 225g of glycidyl methacrylate, 225g of hydroxypropyl acrylate and 4.5g of AIBN to the flask, stir to mix the monomers, dissolve the AIBN solid, and transfer the mixture to a clean reagent bottle for later use. Add 1045g of cyclohexanone to the reactor, stir, and heat to 80°C in a water bath. Add 90g of the above monomer and initiator mixture to the reactor, and use a dropping funnel to evenly add the remaining mixture to the reactor within 2h. After adding all the monomer mixture, continue to react for half an hour. Then heat to 100°C, pre-dissolve 0.5g of AIBN in 4.5g of cyclohexanone to prepare an initiator solution, add the initiator solution to the reactor, and continue to react for half an hour. After the reaction is completed, cool to room temperature to obtain a GMA50HPA50 resin solution with a solid content of 30wt%.

[0113] Example 3

[0114] According to the preparation method of Example 2, the amounts of monomers glycidyl methacrylate and hydroxypropyl acrylate were changed to 171 g and 279 g, respectively, to prepare a GMA38HPA62 resin solution with a solid content of 30%, i.e., poly(glycidyl methacrylate 38%-co-2-hydroxypropyl acrylate 62%).

[0115] Embodiments 4 to 9

[0116] Six dual-color ultraviolet absorbing dyes, p-methoxybenzoic acid, p-fluorobenzoic acid, p-chlorobenzoic acid, p-bromobenzoic acid, p-iodobenzoic acid and ethyl p-hydroxybenzoate, are labeled as dye A, dye B, dye C, dye D, dye E and dye F, respectively. The chemical structural formulas of these dyes are as follows: Figure 1 These dyes were purchased from Aladdin and Sigma Adrich, and the purity was not less than 98 wt%. Examples 4 to 9 These dyes were grafted onto the GMA100 resin obtained in Example 1 by epoxy group grafting, to obtain a total of six different dual-color absorption resins AF.

[0117] The preparation method of the two-color absorption resin is as follows:

[0118] Take a 500mL three-necked glass round-bottom flask and equip it with a mechanical stirrer, a condenser and a dropping funnel. According to the formula in Table 1, add 50g of GMA100 resin solution (30wt%) to the flask, replenish the solvent, add one of the dyes AF, and stir to dissolve. Add 0.15g of tetrabutylammonium bromide catalyst with a solid content of 98%, heat to 110°C in a water bath, and keep warm for 8-11h. After 8h, sample every 30min and titrate with 0.1N standard NaOH solution to determine the residual dye content. Once the residual dye content is less than 2%, cool to room temperature. Repeat the above operation to prepare the six ultraviolet absorbing resins AF shown in Table 1, and the resulting resin solution has a solid content of 30wt%.

[0119] Comparative Examples 1-2

[0120] Take a 500mL three-necked glass round-bottom flask, equipped with a mechanical stirring paddle, a reflux tube, and a dropping funnel. According to the formula in Table 1, add 50g of GMA50HPA50 resin solution with a solid content of 30wt%, supplementary solvent, and select Figure 1 Add one of the benzoic acid (dye R1) and 9-anthracenecarboxylic acid (dye R2) shown in Table 1, stir and dissolve, then add 0.15g of tetrabutylammonium bromide catalyst with a solid content of 98%, heat to 110°C in a water bath, and keep warm for 8-11h. After 8h, sample once every 30min and titrate with 0.1N standard NaOH solution to determine the content of residual dye. Once the residual dye content is less than 2%, cool to room temperature. Repeat the above operation to obtain two comparative ultraviolet absorbing resins R1-R2 shown in Table 1, and the obtained resin solid content is 30wt%.

[0121] Table 1

[0122]

[0123] Embodiments 10 to 15

[0124] Examples 10 to 15 The ultraviolet light-absorbing resins AF prepared in Examples 4 to 9 were mixed with a crosslinking agent, tetramethoxymethyl glycoluril (TMMGU), and a thermal acid generator, triethylammonium p-toluenesulfonate (TEA-PTSA salt), respectively, and then the solid content was adjusted to 5 wt % with cyclohexanone to form the BARC organic coating solution formulations shown in Examples 10 to 14 as shown in Table 2. For comparison, with the same ratio, a 193 nm BARC formulation with benzoic acid as the color-absorbing group was prepared using the light-absorbing resin R1 (Comparative Example 1A), and a 248 nm BARC formulation with benzoic acid as the color-absorbing group was prepared using the light-absorbing resin R2 (Comparative Example 2A).

[0125] Table 2

[0126]

[0127] Example 16

[0128] The BARC organic coating solution formula samples obtained in Examples 10 to 15, and the BARC organic coating solution formula samples of Comparative Example 1A and Comparative Example 2A were respectively spin-coated on the surface of a 12-inch silicon wafer at a speed of 1500 rpm, and baked at 200° C. for 120 seconds to crosslink and cure the coating to obtain a BARC layer. The coating thickness and complex refractive index (n+jk) thereof were measured using an ellipsometer, where n is the refractive index and k is the absorption parameter. Table 3 below shows the refractive index n and the imaginary part k value of the complex refractive index of the BARC coating formed by these organic coating solution formulas for electromagnetic waves with wavelengths of 193 nm and 248 nm.

[0129] Table 3

[0130]

[0131] In Examples 10-15, from Table 3, Figure 2 , Figure 3 , Figure 5 and Figure 6 It can be seen that p-methoxybenzoic acid (dye A), p-chlorobenzoic acid (dye C), p-bromobenzoic acid (dye D), p-iodobenzoic acid (dye E), and methyl p-hydroxybenzoate (dye F) have two relatively strong absorption peaks near 193nm (180-200nm) and 248nm (230-260nm), respectively, and their k values ​​at a wavelength of 193nm are in the range of 0.27 to 0.35, and at a wavelength of 248nm are in the range of 0.17 to 0.28.

[0132] For common PR and silicon substrate, common BARC needs to make the reflection coefficient lower than 2% under the first minimum film thickness (usually 35-50nm ArF lithography and 45-65nm KrF lithography), and its k value needs to reach above 0.45. Obviously, dye AF cannot be used for the first minimum film thickness, and is only suitable for BARC formulations under the conditions of the second and third minimum film thicknesses.

[0133] Examples 10 and 15 are both p-alkoxybenzoate-type BARC dyes, which have relatively high k values ​​at 193 nm and 248 nm and are suitable ArF and KrF BARC dyes.

[0134] Example 11: The BARC with added dye B (p-fluorobenzoic acid) has the strongest absorption at 193nm, with a k value greater than 0.4. However, at 248nm, the k value is only 0.065, which is very weak and can basically only be used as ArF monochrome BARC.

[0135] Example 12: The first, second and third minimum film thicknesses of BARC containing dye C (p-chlorobenzoic acid dye) in ArF applications correspond to film thicknesses of 41nm, 95nm and 150nm, and the corresponding reflectances are 5%, 0.5% and 2%, respectively. At KrF wavelengths, the first, second and third minimum film thicknesses are 46nm, 110nm and 170nm, respectively, and the corresponding reflectances are 11%, 0.5% and 2%, respectively. This dye is a qualified ArF / KrF two-color dye.

[0136] Example 13: The first, second and third minimum film thicknesses of BARC (p-bromobenzoic acid dye) containing dye D in ArF applications are 45nm, 98nm and 160nm, respectively, and the corresponding reflectances are 2.5%, 0.01% and 1%, respectively. For KrF applications, the first, second and third minimum film thicknesses are 48nm, 116nm and 175nm, respectively, and the corresponding reflectances are 6.8%, 0.1% and 0.2%, respectively. This is also a very qualified ArF / KrF two-color dye.

[0137] The above-mentioned p-chlorobenzoic acid dye and p-chlorobenzoic acid dye are dyes with relatively balanced performance under two wavelength conditions.

[0138] In Example 14, the p-iodobenzoic acid dye has strong absorption at 193 nm, but very weak absorption at 248 nm, with a k value of 0.17. Its absorption peak (260 nm) is too red-shifted, and 248 nm is almost at the valley.

[0139] from Figure 4It can be seen that the BARC containing the commonly used KrF dye 9-anthracenecarboxylic acid (Comparative Example 2A) has an extremely strong absorption peak at 256nm, and 248nm is located on a top shoulder of the absorption peak. Although the dye content is significantly lower than that of the BARC containing the dye AF, its k value at 248nm reaches an astonishing 0.5. Therefore, anthracenecarboxylic acid (anthracene fused ring structure) is a very excellent KrF dye. Its shortcomings are: first, the plasma etching speed of the fused ring structure is slow, and the formed BARC is difficult to etch; second, the n value of the film is also low (1.45-1.52), and the corresponding first and second minimum film thicknesses are also correspondingly larger. The k value of the anthracenecarboxylic acid dye at 193nm is low and cannot be used for ArF BARC.

[0140] On the contrary, from Figure 4 As shown, benzoic acid, as a common ArF BARC dye, has very strong absorption at 193nm, but its absorption at 248nm is very weak and cannot be used for KrF BARC.

[0141] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A dual-color photolithography bottom anti-reflection coating common to ArF and KrF, characterized in that: The dual-color photolithography bottom anti-reflective coating is prepared from the following organic coating solution, which is formed by a film-forming substance, an auxiliary agent and a solvent containing a dual-color ultraviolet absorbing dye structure in the molecular structure; the dual-color ultraviolet absorbing dye has strong absorption of electromagnetic waves with wavelengths of 193nm and 248nm, and the dual-color ultraviolet absorbing dye structure is selected from any one of the following: The substructure of the dual-color ultraviolet absorbing dye structure is shown in any of the following formulas: The imaginary part k value of the complex refractive index of the dual-color photolithography bottom anti-reflection coating for electromagnetic waves with wavelengths of 193nm and 248nm is not less than 0.

2.

2. The dual-color photolithography bottom anti-reflection coating according to claim 1, characterized in that: Includes one or more of the following characteristics: 1) The auxiliary agent includes one or more of a cross-linking agent, a heat-activated catalyst, a leveling agent, and a tackifier; 2) The solvent is selected from one or more of propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, 2-hydroxypropyl acetate, 3-methoxypropionic acid methyl ester, 3-ethoxypropionic acid ethyl ester, cyclohexanone, cyclopentanone, phenethyl ether, ethyl acetoacetate, and xylene.

3. The dual-color photolithography bottom anti-reflection coating according to claim 2, characterized in that: Includes one or more of the following characteristics: (i) the substructure of the dual-color ultraviolet absorbing dye is bonded to the polymer via a covalent bond, specifically: the substructure of the dual-color ultraviolet absorbing dye structure is connected to other carbon atoms of the polymer via an oxygen atom or a carbon atom in the formula in the form of one or two non-conjugated covalent bonds; (ii) the organic coating solution contains a film-forming substance having a dual-color ultraviolet absorbing dye structure, a cross-linking agent, and a thermally activated catalyst in a weight ratio of 100: (3-20): (0.1-5); (iii) the weight ratio of the solvent to the remaining components in the organic coating solution is 100:(1-10); (iv) the crosslinking agent is selected from amino resins, which are tetrabutoxymethyl urea, hexamethoxymethyl melamine, tetramethoxymethyl ethyl urea, tetrabutoxymethyl ethyl urea, or oligomers having a molecular weight of 500-2000 Daltons formed from one or more of the above amino resins; (v) The thermally activated catalyst is selected from thermal acid generators.

4. The dual-color photolithography bottom anti-reflection coating according to claim 1, characterized in that: Includes one or more of the following characteristics: (1) The film-forming substance containing the dual-color ultraviolet absorbing dye structure comprises a polymer obtained by polymerization of one or more organic monomers, at least one of the organic monomers containing the dual-color ultraviolet absorbing dye structure; (2) The film-forming substance containing the two-color ultraviolet absorbing dye structure includes at least one polymer grafted with small molecules, and the small molecules contain the two-color ultraviolet absorbing dye structure; the polymer is selected from one or more of vinyl polymers, acrylic resins, methacrylic resins, polyether resins, polyester resins, polyamides, epoxy resins, phenolic resins, phenoxy resins, cellulose, and aldehyde-ketone resins.

5. The dual-color photolithography bottom anti-reflection coating according to claim 4, characterized in that: Includes one or more of the following characteristics: (1a) the film-forming substance containing a dual-color ultraviolet absorbing dye structure is obtained by copolymerizing an acrylate monomer or a methacrylate monomer containing a dual-color ultraviolet dye structure with at least one of hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate and N-hydroxymethyl acrylamide; (2a) The film-forming substance containing a dual-color ultraviolet absorbing dye structure is obtained by reacting a small molecule containing a dual-color ultraviolet dye structure with an active hydroxyl group and grafting the resultant to a polymer having an epoxy side group; the active hydroxyl group is derived from phenol or carboxylic acid; The polymer having epoxy side groups is selected from acrylic polymers or methacrylic polymers.

6. The dual-color photolithography bottom anti-reflective coating according to claim 5, characterized in that: In feature (1a), the film-forming substance containing a dual-color ultraviolet absorbing dye structure includes any one of the following branched repeating units and the following repeating monomers connected to the main chain via an ester group or a carbonyl group: Among them, R1 is selected from any one of halogen, hydroxyl, and low-carbon alkoxy; R2 is selected from any one of divalent alkyl and alkoxy; R3 is selected from hydrogen or methyl, and R4 is selected from any one of C1-C10 alkyl; R1 is selected from chlorine, bromine, methoxy or ethoxy; R2 is selected from ethane-1,2-diyl, propane-1,2-diyl, propane-1,3-diyl or 2-hydroxypropane-1,3-diyl; R3 is selected from hydrogen or methyl; R4 is selected from methyl.

7. The dual-color photolithography bottom anti-reflection coating according to claim 6, characterized in that: The film-forming substance containing the dual-color ultraviolet absorbing dye structure further includes any one or two of the following branched repeating units: Wherein, R4 is selected from hydrogen or methyl.

8. The dual-color photolithography bottom anti-reflection coating according to claim 7, characterized in that: Includes one or more of the following characteristics: (1) The film-forming material containing a dual-color ultraviolet absorbing dye structure includes any one of the following repeating units: Wherein, l, m are natural numbers; R1 is selected from any one of halogen, hydroxyl, and low-carbon alkoxy; R2 is selected from any one of C1-C10 divalent alkyl and alkoxy; R3 and R4 are each independently selected from any one of hydrogen or low-carbon alkyl; R5 is selected from any one of hydrogen, low-carbon alkyl, and low-carbon alkoxy; R1 is selected from any one of chlorine, bromine, hydroxyl, and methoxy; R2 is selected from any one of ethane-1,2-diyl alkyl and 2-hydroxypropane-1,3-diyl; R3 and R4 are each independently selected from hydrogen or methyl; R5 is selected from hydrogen, methyl, or methoxy, (2) The film-forming material containing a dual-color ultraviolet absorbing dye structure includes any one of the following repeating units: Wherein, l, m, n are natural numbers, l accounts for 30-90% of (l+m+n), m accounts for 0-50% of (l+m+n), and n accounts for 5-10% of (l+m+n); R1 is selected from any one of halogen, hydroxyl, and low-carbon alkoxy; R2 is selected from any one of C1-C10 divalent alkyl and alkoxy; R3, R4 and R6 are selected from any one of hydrogen or low-carbon alkyl; R5 is selected from any one of hydrogen, low-carbon alkyl, and low-carbon alkoxy; R1 is selected from any one of chlorine, bromine, hydroxyl, and methoxy; R2 is selected from any one of ethane-1,2-diyl alkyl and 2-hydroxypropane-1,3-diyl; R3, R4, and R6 are each independently selected from hydrogen or methyl; R5 is selected from hydrogen, methyl, or methoxy, (3) The film-forming material containing a dual-color ultraviolet absorbing dye structure includes any one of the following repeating units: Wherein, m and n are positive integers, and m+n is in the range of 10 to 1000; R7 is selected from aliphatic divalent alkyl groups containing low carbon or low carbon oxygen; and R8 is selected from C1 to C10 aliphatic divalent carbonoxy groups.

9. A method for preparing a bottom anti-reflection coating for dual-color lithography according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) taking a film-forming substance containing a dual-color ultraviolet absorbing dye structure and an auxiliary agent according to a weight ratio, mixing them, and adding a solvent to form an organic coating solution; (2) Spin coating the organic coating solution on the substrate surface, and bake and solidify it to obtain a dual-color photolithography bottom anti-reflective coating.

10. The method for preparing a bottom anti-reflective coating for dual-color lithography according to claim 9, characterized in that: The solid content of the organic coating solution is 2wt% to 10wt%, the rotation speed of the spin coating is 1000 to 3000rpm; and / or the baking temperature is 150 to 250°C; and / or the baking time is 60 to 120s.

11. Use of the dual-color ultraviolet absorbing dye structure or the film-forming material containing the dual-color ultraviolet absorbing dye structure in the dual-color lithography bottom anti-reflection coating as claimed in any one of claims 1 to 8 in preparing a lithography anti-reflection coating universal for ArF and KrF excimer laser lithography.

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