JPWO2000003303A1 - Composition for bottom anti-reflective coating and novel polymer dye for use therein - Google Patents

Abstract

(57) [Abstract] A polymer dye having a repeating unit with a cyclic acetal group, as shown in the following formula, is used as a bottom anti-reflective coating material for photolithography. This allows for the production of a bottom anti-reflective coating that has excellent film-forming properties, absorption at the exposure wavelength, step coverage, non-intermixing with the photoresist layer, and a high etching rate. (R represents H, a substituted or unsubstituted alkyl, cycloalkyl, or aryl group; ^R1 represents a substituted or unsubstituted alkyl or aryl group; ^-COOR3 , in which ^R3 represents an alkyl group; ^R2 represents a substituted or unsubstituted alkyl, cycloalkyl, or aryl group; D is an organic chromophore that absorbs light with an exposure wavelength of 150 to 450 nm and represents a substituted or unsubstituted aryl, fused aryl, or heteroaryl group; m and o are integers greater than 0; and n, p, and q are integers including 0.)

Description

TECHNICAL FIELD The present invention relates to a novel bottom antireflective coating composition, a method for fabricating integrated circuits using a photolithography method in which the bottom antireflective coating composition is used to form a bottom antireflective coating between a substrate and a photoresist film, and a novel polymeric dye.
More specifically, the present invention relates to a composition for a bottom antireflective coating comprising at least a solvent and a novel polymeric dye having a cyclic acetal repeating unit, a method for producing an integrated circuit using a photolithography method in which a bottom antireflective coating is formed from the composition, and the novel polymeric dye and a method for producing the same.

BACKGROUND ART Currently, photolithography using photoresist compositions is used to form active elements and wiring portions of integrated circuits and microelectronic devices. The fabrication of integrated circuits or microelectronic devices using photolithography is generally carried out as follows: First, a photoresist material dissolved in a solvent is spin-coated onto a substrate such as a silicon wafer. The resist-coated substrate is then baked to evaporate the solvent in the photoresist composition and form a thin photoresist film that adheres well to the substrate. The wafer with this thin resist film formed is then imagewise exposed to visible or ultraviolet radiation in the wavelength range of 150 to 450 nm. Instead of visible or ultraviolet light, electron beams or X-rays can also be used. Exposure causes a chemical change in the exposed areas of the photoresist film. After imagewise exposure, the substrate is subjected to a development process using an alkaline developer, in which either the unexposed areas (negative resist) or the exposed areas (positive resist) of the photoresist film are dissolved and removed. The open substrate areas formed by the removal of the resist by development are then subjected to further non-selective processing steps to produce the final integrated circuit or microelectronic device.

In the manufacture of the above-mentioned integrated circuits, high integration has been pursued for some time.
Accordingly, there is a need for increasingly finer processing line widths. For this reason, lithography techniques are also shifting from lithography methods using near ultraviolet rays such as g-line (436 nm) and i-line (365 nm) to lithography methods using shorter wavelength rays, such as mid-ultraviolet rays (35
Imaging technology is also shifting to lithography using ultraviolet (UV) light (280-150 nm) or deep UV (240-280 nm). Deep UV lithography, in particular, utilizes KrF (248 nm) or ArF (193 nm) excimer lasers. These excimer laser sources emit monochromatic light. Recently, chemically amplified positive or negative deep UV photoresist compositions compatible with excimer lasers have become commercially available, offering excellent lithographic properties, high resolution, and high sensitivity. Due to their chemical composition and imaging mechanism, current chemically amplified photoresist compositions are generally transparent to the exposure wavelength and do not exhibit nominal sensitivity due to the inhibitory effects of base contaminants present at the photoresist-substrate or photoresist-air interface. By using appropriate deep UV exposure equipment in conjunction with high-performance photoresists, it is possible to form patterns with design rules of quarter microns or less. However, forming such fine patterns requires considerable effort.
Optical effects have become increasingly prone to image distortion and image loss, and there is a strong demand for a method for obtaining resist images with good reproducibility that are not affected by such optical effects.

Problems caused by the above optical effects include the formation of "standing waves," which are well known in the art, caused by substrate reflection of monochromatic light and thin film interference effects. Another problem is "reflective notching," which is known in the art, caused by light reflection from a highly reflective topographic substrate. When forming an image on a highly reflective topographic substrate using a single-layer resist method, this reflective notching makes it difficult to control linewidth uniformity. Light scattering from the topographic features can sometimes cause linewidth variations and even resist loss. These problems are discussed, for example, in (i) M. Horn, Solid State Imaging, Vol. 1, No. 1, pp. 111-114, 2003;
Technol. , 1991(11), p. 57 (1991), (ii) T. B
runner, Proc. SPIE 1466, p. 297 (1991), (
iii) M. Bolsen et al., Solid State Technology. ,1
986(2), p. 83 (1986) and other publications.

Generally, when the resist film thickness changes, the actual exposure light intensity changes due to thin film interference, which in turn changes the linewidth. This change in linewidth is proportional to the swing ratio (S) defined by the following equation (1), and in order to effectively control the linewidth, it is necessary to minimize the swing ratio.

S=4(R ₁ R ₂ ) ^1/2 e ^−αD (1) (wherein R ₁ is the reflectance of the resist-air interface, R ₂ is the reflectance of the resist-substrate interface, α is the optical absorption coefficient of the resist, and D is the film thickness of the resist.) As a method for solving the above-mentioned problem occurring when forming a pattern on a reflective topography, a method for forming a pattern on a reflective topography is disclosed in U.S. Pat. No. 4,575,480 or U.S. Pat.
A method of adding a light-absorbing dye to a photoresist is known, as described in US Pat. No. 6,882,260. This method involves increasing the light absorption coefficient α in the above formula (1). However, when a dye is added to a photoresist to form a radiation-sensitive film with a high optical density to the exposure light, other problems arise, such as reduced sensitivity of the resist, reduced resolution, loss of depth of focus, reduced contrast, and poor cross-sectional shape of the resist pattern. Furthermore, there are problems during the curing process, such as dilution of the resist in an alkaline developer, and sublimation of the dye during film baking.

Another effective method to solve the problems caused by reflections is surface imaging (TS).
The I) method and the multi-layer resist (MLR) method as described in U.S. Pat. No. 4,370,405 are known. However, these methods are not preferable because the process is complicated, difficult to control, and expensive. The single layer resist (SLR) method is usually used because the process is simple and cost-effective.

Another known method is to use a top or bottom anti-reflection coating. This method is simple and preferable for solving the problem caused by thin film interference. This method corresponds to reducing _R1 or _R2 in the above formula (1), thereby reducing the swing ratio S.

Among the above methods, the most effective method is to reduce reflection from the substrate by providing a so-called bottom antireflective coating (BARC). The bottom antireflective coating absorbs light that has passed through the photoresist, preventing it from reflecting light that has passed through the resist. A bottom antireflective coating is formed by applying a thin film of an antireflective composition to the substrate before the photoresist is applied to the substrate. A resist is then applied onto the bottom antireflective coating, exposed to light, and developed. The antireflective coating in the areas where the resist has been removed by development is then etched, for example, with oxygen plasma, to transfer the resist pattern to the substrate. This resist pattern is then subjected to further processes for forming active elements, wiring, etc. During the etching process, the bottom antireflective coating must be etched without significantly reducing the photoresist film.
Therefore, the etching rate of the antireflective composition is very important, and to satisfy this condition, the etching rate of the antireflective composition must be relatively higher than the etching rate of the photoresist.

The bottom anti-reflective coatings are broadly divided into two types based on the material: inorganic bottom anti-reflective coatings and organic bottom anti-reflective coatings. The inorganic bottom anti-reflective coatings include many dielectric anti-reflective coatings such as TiN, TiON, TiW, and spin-on glass with a thickness of 300 Å or less. These are described in detail in (i) C. Noelsch et al.
er et al., Proc. SPIE 1086, p. 242 (1989), (ii)
K. Bather et al., Thin Solid Films, 200, p. 93(
1991), (iii) G. Czech et al., Microelectr. Eng
in., 21, p. 51 (1993). Inorganic dielectric anti-reflective coatings can effectively reduce thin-film interference effects, but they have problems such as the need for complex control to accurately adjust the film thickness, the difficulty of forming a uniform film, the need for special deposition equipment to form the film, the need for substrate pretreatment to promote adhesion before resist application, the need for a separate dry etching pattern transfer step, and the usual difficulty of film removal.

In addition, the organic bottom anti-reflection coating can also effectively control the line width and standing waves, similar to the inorganic anti-reflection coating.
ng et al., Proc. SPIE 469, p. 24 (1984) or W. Is
A dye that absorbs light at the exposure wavelength is added to a polymer film, as described in Hii et al., Proc. SPIE 631, p. 295 (1985). However, antireflective films obtained using this method suffer from the following problems: (1) separation of the dye from the polymer during spin coating, drying, or baking; (2) sublimation of the dye during the hard bake process; (3) dissolution of the dye into the resist solvent; (4) diffusion of the dye into the resist during baking; and (5) interfacial film formation. These problems become more pronounced when a chemically amplified photoresist is used, resulting in a significant degradation of lithographic properties. Therefore, the use of dye-containing antireflective films is not a desirable method. Among these problems, the sublimation problem is particularly problematic because it not only reduces the absorption properties of the antireflective film, but also contaminates expensive equipment and increases particle concentrations in subsequent processes.

Another method for forming an organic antireflective coating has been proposed in which a radiation-absorbing pigment is incorporated into the organic antireflective coating (European Patent Publication No. 744662). However, when this antireflective coating is used, a large number of insoluble particles are generated during processing of the device, resulting in a significant decrease in yield.

Another method has been proposed in which dyes are directly attached to film-forming polymers (see U.S. Pat. No. 5,525,247). However, the materials described in this patent usually require the use of solvents such as cyclohexanone or cyclopentanone, which are hazardous to the human body, to form films. On the other hand, M. Fahey et al.
Proc. SPIE 2195, p. 422 (1994) describes a method of reacting an amino group-containing dye with the acid anhydride group of a vinyl methyl ether-maleic anhydride copolymer. However, this method has the problem that the reaction between the amine and the polymer acid anhydride group does not proceed quantitatively, and as a result, free amine is present in the resulting bottom anti-reflective coating composition (European Patent Publication No. 583205, p. 5, 1).
(Lines 7-20) When a base-sensitive chemically amplified resist composition is used as a resist, the presence of unreacted amines in the bottom antireflective coating can have a detrimental effect on the resist at the bottom antireflective coating-resist interface, resulting in incomplete dissolution of the bottom resist layer in the exposed areas during development, resulting in footing. Furthermore, free dye molecules sublimate during baking and deposit on the manufacturing equipment, causing contamination problems and hazardous to the health of workers. Another problem with this composition is that imide groups are formed during the reaction between the amine and the acid anhydride group. Because imide groups have poor solubility, polar solvents, which are not typically used in photoresist film formation, must be used to dissolve the composition. From a manufacturing perspective, it is ideal for the solvent used to form the photoresist film to be the same as the solvent used to form the bottom antireflective coating. Furthermore, the presence of water formed as a by-product of the imidization reaction can cause coating defects (pinholes) during film formation.

In the above-mentioned publication, Fahey et al. also proposed a system consisting of a copolymer of methyl methacrylate and 9-methylanthracene methacrylate. However, when this copolymer is used, the acid generated in the resist film by exposure light diffuses into the bottom anti-reflective coating, causing footing and intermixing between the resist and the bottom anti-reflective coating, making it unsuitable for practical use. Furthermore, this copolymer is insoluble in solvents such as propylene glycol monomethyl ether acetate (PGMEA) and ethyl lactate (EL), which are preferred photoresist solvents.

U.S. Patent Nos. 5,234,990 and 5,578,676 describe polysulfone and polyurea resins with inherent light absorption in the deep ultraviolet wavelength range. However, both of these condensation products have poor film-forming properties, resulting in poor step coverage and poor image transferability to topographical surfaces. Furthermore, these materials are highly crystalline and prone to cracking, likely due to their high Tg and rigid structure. Bottom antireflective coating compositions must be initially soft to achieve good step coverage during application, and must crosslink and harden after baking to prevent intermixing between the photoresist and the bottom antireflective coating and to prevent diffusion of photogenerated acid.

U.S. Patent No. 5,554,485 and European Patent Publication No. 698823 each describe poly(aryl ether) or poly(aryl ketone) polymers. These polymers have a problem of slow etching rates due to a fairly high content of aromatic units. Polyvinyl naphthalene, described in U.S. Patent No. 5,482,817, also has a similar problem.

European Patent Publication No. 542,008 describes a bottom anti-reflective coating composition comprising a thermal or photoacid generator for curing the bottom anti-reflective coating after application, a phenolic resin binder, and a melamine crosslinker. This composition suffers from poor storage stability due to the presence of the crosslinker and photoacid generator, resulting in the development of film defects. Furthermore, this composition suffers from the problem of a very slow etching rate due to the presence of a large amount of aromatic functional groups.

Japanese Patent Publication No. 221855 of 1998 discloses an anti-reflective coating material composition containing a polymer compound having a structure in which a chromophore having a molar absorption coefficient of 10,000 or more for light of any one of wavelengths of 365 nm, 248 nm, or 193 nm is linked to at least a part of the alcohol moiety of the polymer compound containing vinyl alcohol as a repeating structural unit in the main chain, and a method for forming a resist pattern using the same. However, in order to introduce only bulky polycyclic aromatic groups by acetalization reaction into a polymer compound such as polyvinyl alcohol containing vinyl alcohol as a repeating structural unit in the main chain,
The reaction temperature must be increased and the reaction must be allowed to proceed for a long time. It is also difficult to increase the reaction rate. The above publication describes that a predetermined yield can be obtained by reacting in dioxane solvent at 100°C for 40 hours. However, these conditions tend to lead to decomposition of the organic chromophore group, and therefore, the reaction conditions must be relaxed.

To summarize the above, it is preferable that the bottom anti-reflective coating material has the following properties.

(a) Good film-forming properties, (b) High absorption at the applied exposure wavelength, (c) Non-intermixing with photoresists, (d) Higher etching rates than photoresists, (e) Good step coverage on topography, (f) Practical storage stability, (g) Compatibility and solubility in photoresist solvents and edge bead rinse (EBR) solvents, (h) Suitability with various commercially available resists, (i) Ease of production, high yield. An object of the present invention is to provide a bottom anti-reflective coating composition having the above-mentioned properties preferred as a bottom anti-reflective coating material, a method for producing integrated circuits using the same, and a novel polymer dye and a method for producing the same.

Specifically, a first object of the present invention is to provide a bottom anti-reflective coating composition that absorbs radiation in the wavelength range of 150 to 450 nm, which solves problems associated with reflected light from the substrate and topography during pattern formation.

A second object of the present invention is to provide a bottom antireflective coating composition that has good adhesion to integrated circuit and microelectronic device substrates, excellent coating uniformity, and is non-particle forming.

A third object of the present invention is to provide a bottom anti-reflective coating composition that has a superior etching rate compared to currently available bottom anti-reflective coatings, is well applicable to chemically amplified photoresists, and is free from undercut and footing.

A fourth object of the present invention is to provide novel polymeric dyes containing cyclic acetal groups that are applicable to bottom anti-reflective coating compositions and can be produced easily and in high yield, as well as a method for producing the same.

A fifth object of the present invention is to provide a bottom antireflective coating composition containing a cyclic acetal group-containing polymeric dye and, optionally, a crosslinker and other additives such as a photoacid generator, a plasticizer, or a surfactant.

A sixth object of the present invention is to provide novel polymers and copolymers that can be cured (crosslinked) at the baking temperature of a formed bottom antireflective coating, harden the bottom antireflective coating, prevent penetration of photoresist solvents or photoresist components, and prevent footing caused by intermixing or acid diffusion effects, and that can be easily produced in high yields.

The present invention also provides a method for applying or using an antireflective composition in conjunction with a photoresist on a substrate useful in the manufacture of integrated circuits and microelectronic devices. In a preferred embodiment, the method comprises the steps of: 1) treating the substrate with a primer, 2) applying a bottom antireflective coating composition of the present invention, 3) baking the applied bottom antireflective coating to evaporate the solvent and harden the coating, 4) applying a photoresist over the antireflective coating, 5) drying the photoresist, 6) exposing the photoresist through a mask, 7) developing the resist, and 8) removing the antireflective coating in the open areas.

Other objects will become apparent from the detailed description, preferred embodiments, and examples that follow.

DISCLOSURE OF THE INVENTION It has now been found that the above objects of the present invention can be achieved by using a bottom antireflective coating composition that contains at least a solvent and a novel polymeric dye having cyclic acetal repeat units.

That is, the present invention provides a method for producing a compound comprising at least a solvent and a compound of general formula 1; (wherein R represents a hydrogen atom, a substituted or unsubstituted _C1 to _C20 alkyl group, a substituted or unsubstituted _C6 to _C20 cycloalkyl group, or a substituted or unsubstituted _C6 to _C20 aryl group; ^R1 represents a hydrogen atom, a substituted or unsubstituted _C1 to _C5 alkyl group, a substituted or unsubstituted _C6 to _C10 aryl group, or a ^-COOR3 group ( ^R3 represents a _C1 to _C10 alkyl group); ^R2 represents a substituted or unsubstituted _C1 to _C5 alkyl group, a substituted or unsubstituted _C6 to _C20 cycloalkyl group, or a substituted or unsubstituted C6 to _C20 aryl group.
D is an organic chromophore having an absorption wavelength in the exposure wavelength range ( ₁₅₀ to 450 nm), and is a substituted or unsubstituted _C6 to _C30 aryl group, a substituted or unsubstituted fused _C6 to _C30 aryl group, or a substituted or unsubstituted _C4 to _C30 heteroaryl group; m and o are any integers greater than 0; n, p, and q are 0.
The present invention provides a bottom anti-reflective coating composition containing a polymer dye represented by the formula:

The present invention also provides a method for forming a bottom anti-reflective coating on a semiconductor substrate such as silicon by spin-coating the above-mentioned bottom anti-reflective coating composition on the substrate and baking the substrate to evaporate the solvent, and an anti-reflective coating formed thereby.

The present invention further provides a method for fabricating integrated circuits, which comprises applying a positive or negative photoresist sensitive to radiation in the wavelength range of 150 nm to 450 nm to a substrate coated with the bottom antireflective coating described above, exposing the resist-coated substrate, developing it, and transferring the image to the substrate by wet or dry etching.

The present invention also provides a novel polymer dye represented by the above general formula 1.

The novel polymeric dye represented by the general formula 1 is prepared by reacting polyvinyl alcohol or a derivative thereof with an aromatic chromophore having an aldehyde group and an absorption wavelength in the range of 150 to 450 nm. The film-forming composition containing the polymeric dye of the present invention can absorb radiation in the wavelength range of 150 to 450 nm and may optionally contain additives such as a crosslinker, a thermal or photoacid generator, and a plasticizer or surfactant. The bottom anti-reflective coating composition of the present invention is useful in the manufacture of semiconductor devices because it can avoid problems caused by reflection and scattering of radiation during lithography processes.

The bottom anti-reflective coating of the present invention has a vinyl alcohol type polymer backbone with an acetal
It is based on a radiation absorbing dye that is directly attached via a bond.
According to the present invention, the polymeric dyes represented by general formula 1 are, for example, partially or completely
Hydrolyzed polyvinyl alcohol, poly(vinyl alcohol-co-ethylene
poly(vinyl acetal-co-vinyl alcohol), poly(vinyl acetal
vinyl alcohol-co-vinyl acetate), or partially hydrolyzed
Digested vinyl acetate-co-acrylate block copolymers and chromophores
The compound can be synthesized by using an aldehyde compound as a starting material.
In the synthetic examples given in the examples, the reactions are typically carried out according to the following reaction scheme:
In general, in reaction 1, polyvinyl alcohol is reacted with an aldehyde.
Simultaneous reaction of the derivative R-CHO and the radiation-absorbing carbonyl chromophore D-CHO
In reaction scheme 2, polyvinyl alcohol is partially reacted with an aldehyde.
Coal is used as the starting material, and the radiation-absorbing carbonyl chromophore D-CHO is
It will be responded to.Reaction Scheme 1 (wherein R is a hydrogen atom, a substituted or unsubstituted C₁~C₂₀Alkyl groups, substituted or
unsubstituted C₆~C₂₀Cycloalkyl group or substituted or unsubstituted C₆~C₂₀Ants
D is an organic chromophore that absorbs light at an exposure wavelength (150 to 450 nm),
Substituted or unsubstituted C₆~C₃₀aryl group, substituted or unsubstituted fused C₆~C₃₀
an aryl group or a substituted or unsubstituted C₄~C₃₀represents a heteroaryl group; m,
n and o are integers from 5 to 50,000.Reaction Scheme 2 (wherein R is a hydrogen atom, a substituted or unsubstituted C₁~C₂₀Alkyl groups, substituted or
unsubstituted C₆~C₂₀Cycloalkyl group or substituted or unsubstituted C₆~C₂₀Ants
D is an organic chromophore that absorbs light at an exposure wavelength (150 to 450 nm),
Substituted or unsubstituted C₆~C₃₀aryl group, substituted or unsubstituted fused C₆~C₃₀
an aryl group or a substituted or unsubstituted C₄~C₃₀represents a heteroaryl group; m,
n and o are integers from 5 to 50,000.) The reactions shown in Reaction Schemes 1 and 2 each involve the reaction of an aldehyde R-CHO
and acetalization reactions using D-CHO.
For acetalization, ketones R-CR⁴O and D-CR⁴O (ketal
oxidization reaction), alkyl acetals R—CH(OR⁵)₂and D-CH(OR
⁵)₂(Transacetalization reaction), alkyl ketals R-CR⁴(OR
⁵)₂and D-CR⁴(OR⁵)₂(transketalization reaction) or enol
ethers (wherein D is the same as defined above, and R⁴is determined by R
represents the same thing as defined above, and R⁵is C₁~C₄It also represents an alkyl group.
However, aldehydes are easily available,
In addition, since the reaction is easy, it is more easily used than the compounds other than the above aldehydes.
is preferred.

The reactions shown in Equations 1 and 2 require an acid catalyst.
A strong acid such as sulfuric acid, nitric acid, or hydrochloric acid is used.
Acidic ion exchange resins such as lyst (trade name, manufactured by Fluka AG) can also be used as catalysts. Acidic ion exchange resins are preferred because they can be removed from the reaction mixture by filtration, allowing for the easy production of a final product free of acidic impurities.

The weight average molecular weight (Mw) of the polyvinyl alcohol used in Reaction Schemes 1 and 2
) is generally 500 to 5,000,000. Film forming ability and dissolution
In consideration of the properties, the weight average molecular weight is preferably 2,000 to 100,000.
Useful radiation-absorbing chromophores D include, for example, phenyl, substituted phenyl, benzoyl,
benzyl, substituted benzyl, naphthyl, substituted naphthyl, anthracenyl, substituted anthracenyl
anthraquinonyl, substituted anthraquinonyl, acridinyl, substituted acridinyl
diphenyl, azophenyl, substituted azophenyl, fluorenyl, substituted fluorenyl,
Fluorenonyl, substituted fluorenonyl, carbazolyl, substituted carbazolyl, N-
Alkylcarbazolyl, dibenzofuranyl, substituted dibenzofuranyl, phenanth
Examples of such groups include phenanthrenyl, substituted phenanthrenyl, pyrenyl, and substituted pyrenyl.
However, the radiation-absorbing chromophore D of the present invention is not limited to these groups.
In addition, the substitution in the dye molecule may be linear, branched, or cyclic.
C₁~C₂₀Alkyl, C₆~C₂₀Aryl, halogen, C₁~C₂₀Archi
oxy, nitro, carbonyl, cyano, amide, sulfonamide, imide, chlorine
carboxylic acid, carboxylic acid ester, sulfonic acid, sulfonic acid ester, C₁~C₁₀
Alkylamine or C₆~C₂₀One or more substitutions by groups such as arylamine
It can be a substitute.

Preferred examples of R-CHO in Reaction Scheme 1 include formaldehyde, acetaldehyde, propionaldehyde, butylaldehyde, benzaldehyde,
Examples of R-CHO include substituted benzaldehyde, p-hydroxybenzaldehyde, and p-methoxybenzaldehyde, but it goes without saying that R-CHO is not limited to these.

The organic solvent that can be used in the reaction of polyvinyl alcohol with a carbonyl compound is not particularly limited as long as it is not basic. Preferred solvents include methanol, ethanol, isopropanol, propylene glycol monomethyl ether, ethyl lactate, and glycol. Ethanol is the most preferred solvent, and sulfuric acid is the most preferred acid catalyst.

The above also applies to the use of polyvinyl alcohol obtained by partial hydrolysis having a repeating unit other than vinyl alcohol as a repeating unit, or a copolymer having a repeating unit other than vinyl alcohol or vinyl acetate units. By selecting the repeating unit other than vinyl alcohol, it is possible to adjust the solubility of the polymer dye in a solvent, the glass transition temperature of the polymer dye, the melt viscosity, the affinity with the resist, the surface uniformity during coating, flatness, etc.

Specific examples of monomers forming these other repeating units containing the group ^R1 include ethylene, propylene, acrylates such as methyl acrylate, styrene, and styrene derivatives.
Typical examples of the group ^R2 include methyl, ethyl, propyl, and butyl groups, with the methyl group being preferred.

In General Formula 1, the molar ratios m and o of the components depend on the amounts of D-CHO and R-CHO reacted with polyvinyl alcohol. This ratio also determines the absorption constant k and solubility of the polymer dye. Of course, the amount of m must be sufficient to obtain a bottom anti-reflective coating composition capable of preventing standing waves. The target absorption wavelength and refractive index of the final polymer are also important for obtaining a suitable bottom anti-reflective coating material. The absorption value of the bottom anti-reflective coating is preferably 2 to 40 per micron of film thickness, with 5 to 15 per micron being particularly preferred. This also applies to copolymers. Too high or too low absorption is undesirable for a bottom anti-reflective coating. However, because the absorption and refractive index of the anti-reflective coating depend on the absorption and refractive index of the photoresist layer coated on top of it, there are generally no optimal absorption or refractive index values for a bottom anti-reflective coating. The refractive index of a bottom anti-reflective coating is optimal if it matches the values of the resist layer coated on top of it. The absorption characteristics of a bottom antireflective coating are primarily determined by the molar ratio of monomers containing chromophore D, although the range of this molar ratio can vary depending on the molar absorbance of D. Furthermore, the absorption of an antireflective coating can be optimized for a given wavelength by appropriately selecting substituents on the dye functional group D. Electron-withdrawing or electron-donating groups typically shift the absorption wavelength toward shorter or longer wavelengths, respectively. Similarly, appropriate selection of substituents on any monomer unit in a polymer can enhance the solubility or crosslinkability of the polymer.

The acetalization reaction using the above-mentioned aldehyde derivatives, R-CHO and D-CHO, yields a homogeneous reaction mixture compared to a reaction system without R-CHO. The use of the above-mentioned solvent allows the reaction to proceed sufficiently at a relatively low temperature of around 70°C for 8 to 10 hours, resulting in a high yield of the reaction product. This is advantageous from the standpoint of reaction engineering and protection of the chromophore group. Furthermore, the polymer dye production method using two aldehyde derivatives according to the present invention allows multiple chromophore groups to be bonded to the polymer chain, thereby enabling the same polymer to be used for multiple exposure wavelengths. This is similar to the polymer dye absorbing light at 248 nm KrF laser and 193 nm ArF laser wavelengths described in Example 7 below. These points clearly differ from the prior art described in JP-A-10-221855, which does not use the aldehyde derivative, R-CHO, and are considered to be major features of the present invention.

In addition, the molar ratios of components n, p, and q in General Formula 1 are any integers including 0. These values are appropriately determined depending on the required properties of the polymer dye. For example, p or q may be 0, or both p and q may be 0.

The preferred ranges of m, n, o, p, and q are exemplified by ratios as follows: m=0.
20-0.90, n=0.05-0.30, o=0.01-0.40, p=0-
0.40, q=0.01 to 0.20.

Solubility in a safety solvent is one of the important requirements for a bottom anti-reflective coating material. On the other hand, the solvent must be stable enough to ensure that the bottom anti-reflective coating composition has good film-forming properties.
The solvent must be one that dissolves the polymer dye and other additives (surfactants, plasticizers, crosslinkers). From the viewpoints of safety, solubility, volatility, and film-forming properties, preferred solvents include propylene glycol monomethyl ether acetate (PGMEA), ethyl lactate (EL), propylene glycol monomethyl ether, cyclohexanone, cyclopentanone, 2-heptanone, and combinations thereof. However, the solvents that can be used in the present invention are not limited to these specific examples. The solubility of the polymer dye represented by general formula 1 of the present invention in a solvent depends on the reaction of the reactant R-
This can be adjusted by appropriately selecting CHO.

In addition to the polymer dye and solvent, the bottom anti-reflective coating composition of the present invention may optionally contain surfactants, crosslinkers, acid generators, or other additives to enhance coating performance and form uniform, defect-free films on semiconductor substrates. Examples of surfactants include fluorinated compounds or siloxane-based compounds, but the surfactants that can be used are not limited to these. Examples of crosslinkers include thermal crosslinkers such as blocked isocyanates, acid-catalyzed crosslinkers such as melamine or uracil resins, and epoxy-based crosslinkers. Examples of acid generators include thermal acid generators or photoacid generators.

Another important and desirable property of a bottom antireflective coating is a high etch rate in plasma. This property is primarily controlled by the selection of the polymer dye used in the bottom antireflective coating material. It is well known to semiconductor fabrication engineers that a bottom antireflective coating material should have an etch rate significantly higher than that of the resist itself in order to successfully transfer the pattern to the substrate after exposure and subsequent processing steps.

The etching rate of organic materials is calculated using the Onishi number or the carbon/hydrogen ratio of the polymer. Polymer materials represented by Formula 1 have a high oxygen content and contain aliphatic carbon groups, so they are expected to exhibit a high Onishi number and have a high etching rate. This is one of the advantages of using the polymer dye represented by Formula 1 of the present invention as a bottom anti-reflective coating material.

The glass transition temperature of a bottom antireflective coating material plays an important role in determining its substrate coverage and intermixing characteristics with the applied photoresist. A relatively low glass transition temperature is desirable for achieving high step coverage, while a high glass transition temperature is desirable for preventing miscibility between the bottom antireflective coating and the photoresist film. A photoresist is coated on top of the bottom antireflective coating, exposed, and developed. Mixing between the alkali-insoluble bottom antireflective coating layer and the alkali-soluble photoresist can result in incomplete removal of the photoresist material during development, typically with an alkaline developer. Another problem is that when a chemically amplified photoresist material is coated on a bottom antireflective coating with a low glass transition temperature, the acid formed in the photoresist during exposure diffuses into the bottom antireflective coating, causing distortion of the acid latent image and preventing complete removal of the photoresist material during development. Therefore, it is desirable for the bottom antireflective coating material to have a glass transition temperature at least equal to or greater than the maximum processing temperature used during coating. This can be adjusted in the present invention by manipulating the molar ratios m, n, and o.

The polymeric dye content of the antireflective composition is preferably in the range of about 1% to about 30% by weight. The preferred concentration is determined by the molecular weight of the polymeric dye used and the desired coating thickness of the bottom antireflective coating. The antireflective composition is applied to the substrate by methods well known in the art, such as dipping, spin coating, roller coating, or spray coating. The thickness of the antireflective coating is preferably 30 nm to 1000 nm.

To form a bottom antireflective coating using the method of the present invention, a substrate is coated with the bottom antireflective coating composition of the present invention and the coated substrate is baked on a hot plate or convection oven at a temperature and for a time sufficient to remove the solvent in the coating and crosslink the polymer sufficiently to render it insoluble in photoresist coating solvents or alkaline developers. Preferred baking temperatures and baking times are about 70°C to about 280°C and about 30 seconds to about 30 minutes, respectively. Heating temperatures below 70°C result in excessive residual solvent or insufficient crosslinking. Heating temperatures above 280°C can result in chemical instability of the polymer. Even after being coated and formed on a substrate, the bottom antireflective coating can be subjected to further heating or dry etching. The bottom antireflective coating must also have a sufficiently low metal ion content so as not to adversely affect the electrical characteristics of semiconductor devices. To reduce the metal ion or particle concentration of the polymer solution, processes such as passage through an ion exchange column, filtration, or extraction can be used.

In the present invention, a bottom anti-reflective coating is formed on a substrate using the bottom anti-reflective coating composition of the present invention, and then a positive or negative photoresist sensitive to radiation in the wavelength range of 150 nm to 450 nm is applied to the bottom anti-reflective coating. The substrate coated with the resist is exposed and developed, and the image is transferred to the substrate by wet or dry etching, and further processed as required to produce an integrated circuit.

The bottom anti-reflective coating material of the present invention can be suitably applied to both positive and negative photoresist materials, including, but not limited to, those made of a novolak resin and a photosensitive compound such as quinone diazide, and those made of a substituted polyhydroxystyrene and a photoactive compound.

BEST MODE FOR CARRYING OUT THE INVENTION The bottom anti-reflective coating compositions of the present invention, their preparation and use are further illustrated by the following application examples and examples. However, these examples are presented for illustrative purposes only and are not intended to limit or restrict the scope of the invention in any way, nor should they be construed as imparting conditions, parameters or values that must be exclusively utilized to practice the invention.

Application Examples The general methods described below were used to evaluate bottom antireflective coating compositions of the present invention unless otherwise specified.

A 2 wt. % solution of the bottom anti-reflective coating material dissolved in a suitable solvent was filtered using 0.5 and 0.2 micron filters and spin-coated onto a 4-inch silicon wafer at an appropriate spin speed for 40 seconds to produce a film thickness of 60 nm after baking at 200°C for 60 seconds. The resulting film was inspected for surface defects using a high-resolution microscope. The optical constants n (refractive index) and k (absorption coefficient) of the film were measured using an ellipsometer at wavelengths of 248 nm or 356 nm.

Next, a positive or negative acid-catalyzed deep ultraviolet photoresist (film thickness: about 700 nm) or a positive or negative i-line novolak resin (
A film thickness of approximately 1000 nm was applied by spin coating for 40 seconds at an appropriate spin speed, followed by a soft bake at 90-110°C for 60 seconds, depending on the resist material.
The deep UV resist was exposed by a stepper operated with an excimer laser (248 nm), and the i-line (356 nm) resist was exposed by an i-line stepper using a reticle with a line-and-space pattern. Following exposure, the deep UV resist was post-exposure baked at 90-110°C.
The photoresist was developed using a 0.26N tetramethylammonium hydroxide developer solution for 60 seconds at 23°C to form a resist pattern. The resist pattern was checked for resolution, standing wave formation, reflective notching, and footing using a scanning electron microscope. To evaluate the step coverage of the bottom anti-reflective coating material, the silicon substrate was first etched at 100°C with a conventional i-line photoresist.
The bottom antireflective coating material was then coated at a film thickness of 100 nm, imagewise exposed, developed, and hard baked at 200° C. The bottom antireflective coating material was then applied to the 100 nm film thickness applied by the image.
The bottom anti-reflective coatings were coated onto wafers with a 0 nm step height. The step coverage of the bottom anti-reflective coatings was then analyzed using a scanning electron microscope. The etch rates of the bottom anti-reflective coating materials were evaluated using oxygen and fluoride gas plasmas.

Example 1: Polyvinyl alcohol (PVA), 9-anthraldehyde (9-
Synthesis of polymer dye from (AA) and propionaldehyde (PA) and its application as bottom anti-reflective coating. In a 300 ml flask, polyvinyl alcohol (Wako Pure Chemical Industries, Ltd., degree of polymerization (D
P)500) 22.0 g (0.5 mol), ethanol 150 g, 9-anthraldehyde 25.78 g (0.125 mol), propionaldehyde 7.26 g (
0.125 mol), 2,6-di-t-butyl-4-methylphenol 0.15 g
and 0.25 g of concentrated sulfuric acid were added. This mixture was heated at 70° C. for 8 hours in a nitrogen atmosphere.
The reaction mixture was heated and stirred for 1 hour. The reaction mixture was cooled, and the resulting precipitate was filtered, dissolved in tetrahydrofuran (THF), and precipitated twice from THF into water. The resulting yellow powder was dried under vacuum (1 Torr) at 40°C. The k value of this polymer was measured using an ellipsometer and found to be 0.4 at 248 nm. The polymer was dissolved in cyclohexanone at a concentration of 2 wt%, filtered, and coated according to the above Application Example to form a bottom anti-reflective coating. A positive deep-UV resist AZ ^™ DX1100 commercially available from Clariant Japan Co., Ltd. was spin-coated onto this anti-reflective coating and soft-baked at 110°C to form a 755 nm thick resist film. The resist film was then exposed to a dose of 52 mJ/cm2 using a deep-UV stepper (Nikon EX-10B) equipped with a 248 nm ^KrF laser. The exposed wafer was then heated at 90°C for 60 minutes.
The resist was baked for 2 seconds, developed by puddle development at 23° C. for 60 seconds, rinsed, and then dried.

When the line and space pattern was observed using a scanning electron microscope, it was found that the polymer dye suppressed the reflected light from the substrate, and therefore no standing waves were generated. The resist line pattern profile was straight, and the space area was almost clean, with no scum or residue.
The etching rate using oxygen-trifluoromethane gas plasma at 0 W is
The rate was 100 nm/min.

Example 2: As a deep ultraviolet photoresist, a deep ultraviolet positive photoresist AZ ^™ DX1200P manufactured by Clariant Japan was used, prebaked at 90° C., and the film thickness was 970 nm.
Example 1 was repeated except that the exposure dose was 28 mJ/cm ² and the post-exposure bake was 105°C.

The formed pattern had no footing in the line portion and no scum in the space portion.Furthermore, the profile was smooth due to the absence of standing waves.

Example 3: As a deep ultraviolet photoresist, a deep ultraviolet positive photoresist AZ ^™ DX1300P manufactured by Clariant Japan was used, prebaked at 90° C., and the film thickness was 715 nm.
Example 1 was repeated except that the exposure dose was 13 mJ/cm ² and the post-exposure bake was 110°C.

The formed pattern had no footing in the line portion and no scum in the space portion.Furthermore, the profile was smooth due to the absence of standing waves.

Example 4: Synthesis of polymeric dye from polyvinyl alcohol, 9-anthraldehyde and propionaldehyde and application as bottom anti-reflective coating. In a 300 ml flask, polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd., degree of polymerization 50
0) 22.0 g (0.5 mol), ethanol 150 g, 9-anthraldehyde 25.78 g (0.125 mol), propionaldehyde 7.26 g (0.12
0.5 mol), 2,6-di-t-butyl-4-methylphenol 0.15 g, and Amberlyst 15 (Fluka AG, acidic ion exchange resin, catalyst) 1 g
20 g of ammonium hydroxide was added. The mixture was heated and stirred at 70°C for 8 hours in a nitrogen atmosphere. The reaction mixture was cooled to room temperature, and the solid phase was collected by filtration and dissolved in tetrahydrofuran (THF). After removing the insoluble portion, which consisted mainly of Amberlyst 15, the dye was precipitated twice from the THF into water. The resulting polymer dye was dried under vacuum (1 Torr) at 40°C. The k value of this polymer at 248 nm measured by ellipsometry was 0.
The viscosity was 39. This polymer was dissolved in cyclohexanone to a concentration of 2% by weight, filtered, and then coated in the same manner as in Example 1 to form a bottom anti-reflective coating. A positive deep ultraviolet resist AZ ^™ DX1100 manufactured by Clariant Japan was spin-coated on this anti-reflective coating, and the coating was treated in the same manner as in Example 1.

The line and space pattern formed showed no standing waves. The profile was straight, and the spaces were clean and free of scum or residue. The etching rate of the bottom anti-reflective coating using oxygen-trifluoromethane gas plasma at 60 W was 100 nm/min.

Example 5: As a deep ultraviolet photoresist, a deep ultraviolet positive photoresist AZ ^™ DX2034P manufactured by Clariant Japan was used, prebaked at 90° C., and the film thickness was 570 nm.
Example 4 was repeated except that the exposure dose was 34 mJ/cm ² and the post-exposure bake was 105°C.

The resulting pattern had no footing in the line area and no scum in the space area. Furthermore, the profile was smooth due to the absence of standing waves. The resolution of the AZ ^™ DX2034P photoresist on the bottom anti-reflective coating in this example was 0.20 μm or better.

Example 6: As a deep ultraviolet photoresist, APEX, a deep ultraviolet positive photoresist manufactured by Shipley Co., Ltd.
E ("APEX" is a trademark), pre-baked at 90°C, film thickness 725nm
Example 4 was repeated except that the exposure dose was 11 mJ/cm ² and the post-exposure bake was 110°C.

The formed pattern had no footing in the line portion and no scum in the space portion.Furthermore, the profile was smooth due to the absence of standing waves.

Example 7: Synthesis of polymeric dye from polyvinyl alcohol, 9-anthraldehyde and 4-hydroxybenzaldehyde (4-HBA) and application as bottom anti-reflective coating. In a 300 ml flask, polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd., degree of polymerization 50
0) 22.0 g (0.5 mol), ethanol 150 g, 9-anthraldehyde 25.78 g (0.125 mol), 4-hydroxybenzaldehyde 13.43
g (0.125 mol), 2,6-di-t-butyl-4-methylphenol 0.1
This mixture was heated to 70° C. in a nitrogen atmosphere.
The mixture was heated and stirred at 40°C for 8 hours. The reaction mixture was cooled to room temperature, and the solid phase was filtered and dissolved in tetrahydrofuran (THF). After removing insoluble materials, the THF solution was precipitated twice in water. The product was dried under vacuum (1 Torr) at 40°C. The k value of this polymer was measured using an ellipsometer. The k value at 248 nm was 0.32. This polymer was dissolved in cyclohexanone to a concentration of 2 wt %, filtered, and coated according to the above Application Example to form a bottom anti-reflective coating. A positive deep UV resist AZ ^™ DX1100 (manufactured by Clariant Japan) was spin-coated onto this anti-reflective coating, and the process was carried out in the same manner as in Example 1.

The bottom anti-reflective coating used in this example is compatible with not only 248 nm KrF laser irradiation exposure but also 193 nm ArF laser irradiation exposure, with a k value of 0.32.

Because the reflected light from the substrate was suppressed, no standing waves were observed in the formed line and space pattern. The pattern profile was straight, and the spaces were clean without scum or residue. The etching rate of the bottom anti-reflective coating using oxygen-trifluoromethane gas plasma at 60 W was 90 nm/min.

Example 8: Instead of the deep ultraviolet resist AZ ^™ DX1100, a negative deep ultraviolet photoresist TDUR N9 (TDUR is a trademark) manufactured by Tokyo Ohka Kogyo Co., Ltd. was used.
Example 7 was repeated except that the exposure temperature was 730 nm, the exposure dose was 44 mJ/cm ² and the post-exposure bake was 130°C.

Example 9: Instead of the deep ultraviolet resist AZ ^™ DX1100, Shipley's positive deep ultraviolet photoresist UVIII ("UVIII" is a trademark) was used, and the pre-baking was performed at 130° C.
Example 7 was repeated except that the film thickness was 625 nm, the dose was 21 mJ/cm ² and the post-exposure bake was 130°C.

Example 10: Instead of the deep ultraviolet resist AZ ^™ DX1100, a positive type i
90° C. pre-baking using AZ ^™ PR1024, a deep UV photoresist
Example 7 was repeated except that the film thickness was 350 nm, the deep UV dose was 32 mJ/cm ² , and no post-exposure bake was performed.

In the patterns obtained in Examples 8, 9, and 10, no footing was observed in the line portions and no scum was observed in the space portions. Furthermore, since there were no standing waves, the photoresist profile was smooth.

Example 11: Synthesis of polymeric dye from 80% hydrolyzed polyvinyl alcohol, 9-anthraldehyde and propionaldehyde and application as bottom anti-reflective coating. In a 300 ml flask, 25 g of polyvinyl alcohol (manufactured by Aldrich, weight average molecular weight Mw=9,000-10,000, degree of hydrolysis 80%), 150 g of ethanol, 25.78 g (0.125 mol) of 9-anthraldehyde, 7.26 g (0.125 mol) of propionaldehyde, 2,6-di-t-butyl-4-methyl-2,6-diisopropyl ...
0.15 g of methylphenol and 0.25 g of concentrated sulfuric acid were added. The mixture was heated and stirred at 70°C for 8 hours in a nitrogen atmosphere. The reaction mixture was cooled, diluted with ethanol, filtered, and precipitated twice in water using THF as a second solvent. The resulting polymer was dried at 40°C under vacuum (1 Torr). The k value of this polymer at 248 nm measured using an ellipsometer was 0.35. The polymer was dissolved in ethyl lactate to a concentration of 2 wt%, filtered, and coated according to the above application example to form a bottom antireflective coating. A positive deep ultraviolet resist AZ ^™ DX1100 (manufactured by Clariant Japan) was spin-coated onto this antireflective coating, and the same process as in Example 1 was performed. The formed lines showed no standing waves, and the spaces showed no scum or residue.

Example 12 A deep UV negative resist having the following composition was coated onto the bottom antireflective coating described in Example 11.

(Composition) 80 parts by weight of 4-hydroxystyrene/styrene (8/2) copolymer (weight average molecular weight 12,000), 20 parts by weight of hexamethoxymethylmelamine (distilled), 1 part by weight of tribromomethylphenylsulfone, 0.1 part by weight of tributylamine. After coating, the resist was soft-baked at 110°C for 60 seconds, exposed to an exposure dose of 24 mJ/ ^cm2 , and post-exposure baked at 120°C for 60 seconds. The process described in Example 1 was then carried out. Some scum was observed in the unexposed areas of the resulting pattern (footing). For this reason, 5% by weight of Kronate (registered trademark) thermal crosslinker (Nippon Polyurethane (
When a scum-free line and space pattern was obtained, the pattern was linear and free of standing waves.

The etch rate of the bottom antireflective coating using an oxygen-trifluoromethane gas plasma at 60 W was 105 nm/min.

Example 13: Synthesis of polymeric dye from vinyl alcohol-ethylene copolymer (PVA-Et), 9-anthraldehyde, and propionaldehyde and application as a bottom anti-reflective coating. In a 300 ml flask, 22 g of vinyl alcohol-ethylene copolymer (manufactured by Aldrich, ethylene content 27 mol%), 150 g of o-xylene, 25.78 g (0.125 mol) of 9-anthraldehyde, and 3.6 g of propionaldehyde were added.
(0.063 mol), 2,6-di-t-butyl-4-methylphenol 0.15
This mixture was heated to 120° C. in a nitrogen atmosphere.
The mixture was heated and stirred at RT for 8 hours. The reaction mixture was cooled, diluted, and filtered. The resulting viscous solution was precipitated twice into a 70:30 v/v ethanol:water mixture.
The resulting polymer was dried under vacuum (1 Torr) at 40°C. The k value of this polymer at 248 nm measured by ellipsometry was 0.38. This polymer was dissolved in ethyl lactate at a concentration of 2 wt %, filtered, and then coated as a bottom antireflective coating as described in General Coating Test. A positive deep UV resist, AZ ^™ DX1100 (manufactured by Clariant Japan), was spin-coated onto this antireflective coating, and the same process as in Example 1 was carried out.

Because the reflected light from the substrate was suppressed, no standing waves were observed in the formed line and space pattern. The pattern profile was linear, and the spaces were clean with no scum or residue.

Similar results were obtained with the positive deep UV photoresist AZ ^™ DX2034 as well as the deep UV negative resist described above in Example 12. The etch rate of the bottom antireflective coating material using an oxygen-trifluoromethane gas plasma at 60 W was 90 nm/min.

Comparative Example 1: Synthesis of polymer dye from polyvinyl alcohol and 9-anthraldehyde and application as bottom anti-reflective coating. In a 300 ml flask, polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd., degree of polymerization 50
22.0 g (0.5 mol) of 9-anthraldehyde (C10), 150 g of ethanol, 25.78 g (0.125 mol) of 9-anthraldehyde, 0.15 g of 2,6-di-t-butyl-4-methylphenol, and 0.25 g of concentrated sulfuric acid were added. The mixture was heated and stirred at 70°C for 8 hours under a nitrogen atmosphere. The reaction mixture was cooled and filtered, and the solid was dissolved in tetrahydrofuran (THF). After removing a small amount of insoluble material, the THF solution was precipitated twice into water. The resulting yellow powder was dried under vacuum (1 Torr) at 40°C. The k value of this polymer at 248 nm measured by ellipsometry was 0.42.
This polymer was dissolved in cyclohexanone to a concentration of 2% by weight, filtered, and then
A bottom anti-reflective coating was formed by coating in accordance with the above-mentioned Application Example. A positive deep ultraviolet resist AZ ^™ DX1100 manufactured by Clariant Japan was spin-coated onto this anti-reflective coating, and the same treatment as in Example 1 was carried out.

The line-and-space pattern formed showed no standing waves due to the suppression of light reflected from the substrate. The pattern profile was linear, and the spaces were clean and free of scum or residue. The etching rate of the bottom anti-reflective coating using oxygen-trifluoromethane gas plasma at 60 W was 105 nm/min.

Comparative Example 2 Comparative Example 1 was repeated except that polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd., degree of polymerization 1000) was used in place of polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd., degree of polymerization 500) during synthesis.

Comparative Example 3 Comparative Example 1 was repeated except that partially hydrolyzed polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd., degree of polymerization 1000) was used in place of polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd., degree of polymerization 500) during synthesis.

Comparative Example 4 Comparative Example 1 was repeated except that partially hydrolyzed polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd., degree of polymerization 2800) was used in place of polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd., degree of polymerization 500) during synthesis.

Comparative Example 5 Comparative Example 1 was repeated except that partially hydrolyzed polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd., degree of polymerization 3500) was used in place of polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd., degree of polymerization 500) during synthesis.

In all of Comparative Examples 2 to 5, no footing was observed in the line portion, and no scum was observed in the space portion. Furthermore, the absence of standing waves resulted in a smooth photoresist profile. However, as the degree of polymerization of the polymer used increased, the step coverage characteristics deteriorated, and the resulting coating tended to fail to form a coating conforming to the steps.

The yields of the acetalization reactions described in Examples 1, 4, 7, 11 and 13 and Comparative Examples 1 to 5 are shown in Table 1.

It is clear from Table 1 that under the given reaction conditions, the use of an alkyl or benzaldehyde derivative gives a reaction product in higher yield than the reaction of anthraldehyde alone.

Effect of the Invention The bottom anti-reflective coating composition of the present invention can be used with solvents commonly used in forming photoresist films, and has excellent storage stability, film formability, and step coverage. Furthermore, bottom anti-reflective coatings formed using this bottom anti-reflective coating composition exhibit high absorption at the exposure wavelength, thus eliminating problems of standing waves and reflective notching, as well as intermixing with the photoresist layer, and also exhibiting excellent properties such as a high etching rate. Therefore, by using the bottom anti-reflective coating composition of the present invention, it is possible to easily form fine resist patterns with high resolution and excellent shape, and by processing semiconductor substrates on which this resist pattern has been formed, it is possible to easily manufacture integrated circuits with the desired integration density.

INDUSTRIAL APPLICABILITY As described above, the novel polymer dye of the present invention can be used as a bottom anti-reflective coating material, and by using a bottom anti-reflective coating composition containing this polymer dye, integrated circuits with high integration density can be manufactured easily and with high yield.

─────────────────────────────────────────────────────── Continued from the front page (51) Int.Cl. ⁷ Identification symbol FI H01L 21/30 H01L 21/30 (72) Inventor Kang Wenbin Clariant Japan Co., Ltd., 3810 Chihama, Daito-cho, Ogasa-gun, Shizuoka Prefecture (72) Inventor Tanaka Hatsuyuki Clariant Japan Co., Ltd., 3810 Chihama, Daito-cho, Ogasa-gun, Shizuoka Prefecture (72) Inventor Kimura Ken Clariant Japan Co., Ltd., 3810 Chihama, Daito-cho, Ogasa-gun, Shizuoka Prefecture (72) Inventor Nishiwaki Yoshinori Clariant Japan Co., Ltd., 3810 Chihama, Daito-cho, Ogasa-gun, Shizuoka Prefecture (Note) This publication is based on the gazette published internationally by the International Bureau of Patents (WIPO). The effect of the international publication of the Japanese patent application (Japanese utility model registration application) related to this publication arises pursuant to Article 184-10, Paragraph 1 of the Patent Act (Article 48-13, Paragraph 2 of the Utility Model Act), and is unrelated to this publication.

Claims (18)

[Claims] 1. A compound comprising at least a solvent and a compound of general formula 1; (wherein R represents a hydrogen atom, a substituted or unsubstituted _C1 to _C20 alkyl group, a substituted or unsubstituted _C6 to _C20 cycloalkyl group, or a substituted or unsubstituted _C6 to _C20 aryl group; ^R1 represents a hydrogen atom, a substituted or unsubstituted _C1 to _C5 alkyl group, a substituted or unsubstituted _C6 to _C10 aryl group, or a ^-COOR3 group ( ^R3 represents a _C1 to _C10 alkyl group); ^R2 represents a substituted or unsubstituted _C1 to _C5 alkyl group, a substituted or unsubstituted _C6 to _C20 cycloalkyl group, or a substituted or unsubstituted C6 to _C20 aryl group.
D is an organic chromophore having an absorption wavelength in the exposure wavelength range ( ₁₅₀ to 450 nm), and is a substituted or unsubstituted _C6 to _C30 aryl group, a substituted or unsubstituted fused _C6 to _C30 aryl group, or a substituted or unsubstituted _C4 to _C30 heteroaryl group; m and o are any integers greater than 0; n, p, and q are 0.
2. A bottom anti-reflective coating composition for use in photolithography, comprising a polymer dye represented by the formula: [Claim 2] D represents phenyl, substituted phenyl, benzyl, substituted benzyl, naphthyl, substituted naphthyl, anthracenyl, substituted anthracenyl, anthraquinonyl, substituted anthraquinonyl, acridinyl, substituted acridinyl, azophenyl, substituted azophenyl, fluorenyl, substituted fluorenyl, fluorenonyl, substituted fluorenonyl, carbazolyl, substituted carbazolyl, N-alkylcarbazolyl, dibenzofuranyl, substituted dibenzofuranyl, phenanthrenyl, substituted phenanthrenyl, pyrenyl or substituted pyrenyl, and the substitution is linear, branched or cyclic C
2. The bottom anti-reflective coating composition of claim _{1 ,} which is substituted with one or more groups selected from the group consisting of ₁ to _C20 alkyl, _C6 to _C20 aryl, halogen, _C1 to _C20 alkyloxy, nitro, carbonyl, cyano, amide, sulfonamide, imide, carboxylic acid, carboxylic acid ester, sulfonic acid, sulfonic acid ester, _C1 to C10 alkylamine, or C6 to _C20 arylamine. 3. The bottom anti-reflective coating composition of claim 1, wherein R represents any one of hydrogen, methyl, ethyl, propyl, butyl, nitrophenyl, hydroxyphenyl, and methoxyphenyl. 4. The bottom anti-reflective coating composition of claim 1, wherein ^R2 represents methyl, ethyl, propyl, phenyl, naphthyl, or anthracenyl. 5. The bottom anti-reflective coating composition of claim 1, wherein D represents a substituted or unsubstituted phenyl, naphthyl, or anthracenyl. 6. The bottom anti-reflective coating composition of claim 5, wherein p is 0. 7. The bottom anti-reflective coating composition of claim 1, wherein the polymer dye represented by general formula 1 has a weight average molecular weight (Mw) of 2,000 to 200,000. 8. 50 to 95 parts by weight of the solids are a polymeric dye represented by general formula 1,
2. The bottom anti-reflective coating composition of claim 1, wherein 50 to 5 parts by weight is a thermal crosslinking agent. 9. The bottom anti-reflective coating composition of claim 8, wherein the crosslinking agent is melamine, blocked isocyanate, uracil, or an epoxy-based crosslinking agent. [Claim 10] A composition for bottom anti-reflection coating described in claim 1, characterized in that 50 to 95 parts by weight of the solid is a polymer dye represented by general formula 1, 50 to 5 parts by weight is a thermal crosslinking agent, and 1 to 10 parts by weight is an acid generator. 11. The crosslinking agent is selected from the group consisting of melamine, blocked isocyanate, uracil,
11. The bottom anti-reflective coating composition of claim 10, wherein the acid generator is any one of an onium salt, a diazomethane compound, and nitrobenzyl tosylate. [Claim 12] A composition for bottom anti-reflective coating according to claim 1, wherein the polymer dye represented by general formula 1 is dissolved in cyclohexanone, propylene glycol monomethyl ether acetate, ethyl lactate, methyl amyl ketone, or a mixture of these solvents at a concentration of 1 to 10% by weight. 13. A method for producing a semiconductor substrate comprising the steps of: a) dissolving at least a polymeric dye of formula 1 according to claim 1 in an organic solvent; b) filtering the resulting solution; and spinning, spraying, or otherwise dissolving the filtered solution on a semiconductor substrate.
a) applying a solvent to a semiconductor substrate by immersion or roller coating; and b) removing the solvent by heating to form a substrate coated with the bottom anti-reflective coating composition of claim 1. [Claim 14] A method for manufacturing an integrated circuit, comprising applying a positive or negative photoresist sensitive to radiation in the wavelength range of 150 nm to 450 nm onto a semiconductor substrate coated with a thin film of the bottom anti-reflective coating composition of claim 1, exposing the resist-coated substrate, developing it, and wet or dry etching it to transfer the image to the substrate. 15. The method for manufacturing an integrated circuit according to claim 14, wherein the photoresist comprises a novolak resin, a photosensitive compound, and a solvent. 16. The method for fabricating an integrated circuit according to claim 14, wherein the photoresist comprises a substituted polyhydroxystyrene, a photoactive compound, and a solvent. [Claim 17] General formula 1;(wherein R is a hydrogen atom, a substituted or unsubstituted C₁~C₂₀Alkyl groups, substituted or
unsubstituted C₆~C₂₀Cycloalkyl group or substituted or unsubstituted C₆~C₂₀Ants
represents a methyl group, and R¹is a hydrogen atom, substituted or unsubstituted C₁~C₅Alkyl groups, substituted
or unsubstituted C₆~C₁₀aryl group, -COOR³Group (R³is C₁~C₁₀a
represents an alkyl group;²is substituted or unsubstituted C₁~C₅Alkyl group,
Substituted or unsubstituted C₆~C₂₀Cycloalkyl group or substituted or unsubstituted C₆~C
₂₀represents an aryl group, and D is an organic chromophore having an absorption wavelength in the range of 150 to 450 nm.
and substituted or unsubstituted C₆~C₃₀aryl group, substituted or unsubstituted fused C₆
~C₃₀an aryl group or a substituted or unsubstituted C₄~C₃₀Represents a heteroaryl group.
where m and o are any integers greater than 0, and n, p, and q are any integers including 0.
(where x is an integer.) A polymer dye represented by the formula: 18. A method for producing a polymer dye represented by formula (I) according to claim 17.