JPH0915862A - Resist composite and forming method of resist pattern - Google Patents

Abstract

PURPOSE: To provide a resist composite which has a practicable sensitivity, and can form a fine resist pattern free from swelling which is never influenced by environmental change of resist process. CONSTITUTION: This composite contains (a) a polymer mixture soluble to basic aqueous solution which is composed of a phenolic resin and a (meth)acrylate polymer, and has a dissolving speed to 2.38% TMAH aqueous solution of 100-2000Å/sec, and (b) dissolution inhibitor compound.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a resist composition, and more specifically, it can use light having a shorter wavelength such as an excimer laser as an imaging radiation and develops a basic aqueous solution after exposure. A resist composition capable of performing The present invention also relates to a method for forming a positive resist pattern using such a resist composition. The resist composition of the present invention is distinguished from a conventional chemically amplified resist in terms of its reaction mechanism, and can be defined as a “non-chemically amplified resist”.

[0002]

2. Description of the Related Art In recent years, high integration of semiconductor integrated circuits has progressed, and LSIs and VLSIs have been put into practical use. The minimum line width of a wiring pattern extends to a sub-half micron area. For this reason, it is essential to establish a fine processing technology, and in the field of lithography,
The wavelength of the ultraviolet light of the exposure light source has been shifted to a short wavelength in the far ultraviolet region, and the development of an exposure apparatus using a light source of a wavelength in the deep ultraviolet region has been actively pursued. Along with this, there is an urgent need to develop a resist material that absorbs light at a short wavelength as described above, has high sensitivity, and has high dry etching resistance.

Currently, as a new exposure technique in semiconductor manufacturing, a krypton fluoride excimer laser (wavelength 248) is used.
nm, hereinafter KrF) has been actively researched, and there is an urgent need to develop a resist having good sensitivity and resolution in such a short wavelength region and having stability. Is coming. As a resist having a high sensitivity and a high resolution that can be applied to such a short wavelength light source, a resist composition using a concept called a chemically amplified type is disclosed by H.M. Has been presented by Ito et al. (Eg, JM J. Frechet et al.,
Proc. Microcircuit Eng. , 26
0 (1982), H.M. Ito et al., Digest of
Technical Papers of 1982
Symposium on VLSI Technology
Ogy, 86 (1983), H.A. Ito et al., “Poly
mers in Electronics ”, ACS
Symposium Series 242, T.W. Da
Vidson Ed., ACS, 11 (1984), and US Pat. No. 4,491,628). The basic concept of the resist composition is, as can be easily understood from the above-mentioned documents and the like, to cause a catalytic reaction in the resist film to improve the apparent quantum yield, and thus to improve the sensitivity of the resist composition. It is based on trying to achieve

Currently, t-butoxycarbonylpolyvinylphenol (t-BOCPV), which has been very extensively studied,
As an example of a chemically amplified resist in which a photo-acid generator (PAG) having a function of generating an acid by light is added to P), in the exposed portion of the resist, heating after exposure, so-called “PEB (post-exposure)” is performed. ), The t-BOC group is eliminated to give isobutene and carbon dioxide. Further, the above-mentioned deprotection reaction progresses in a chain by using the protonic acid generated upon elimination of t-BOC as a catalyst, and the polarity of the exposed portion is largely changed. In the resist of this example, a resist pattern can be easily formed by selecting an appropriate developing solution that can cope with a large change in the polarity of the exposed portion.

However, since the chemically amplified resist using the photo-acid generator uses the acid catalyzed reaction as described above, even if a very small amount of a basic substance exists in the clean room atmosphere in which the resist process is performed, There are problems such as a large decrease in sensitivity, a change in pattern size, and a change in pattern profile (so-called “T-top” shape formation). Also, because it is based on the catalytic chain reaction,
It has the essential problem of being susceptible to environmental changes.

A resist composition in which an alkali-soluble novolac resin is used as a base resin and a hydrophobic naphthoquinonediazide-substituted compound called PAC (photoactive compound) is added as a dissolution inhibitor is also widely known ( For example, US Pat. Nos. 3,666,473 and 4,11
5,128 and 4,173,470; F.
Thompson, Introduction to
Microlithography, ACS, No. 2
19, 112-121, etc.). Such a resist composition can be applied to a wide range of processes by appropriately changing the structure of the naphthoquinonediazide-substituted compound added as a dissolution inhibitor and its esterification rate, the molecular weight and molecular weight distribution of the base resin, and the like. , Is widely used as a positive photoresist in photolithography using g rays and i rays, which are ultraviolet rays, as an exposure light source.

The reaction mechanism of the above resist composition is that the hydrophobic naphthoquinonediazide substituted compound (PAC) is
It is based on the fact that exposure to ultraviolet light causes a photochemical reaction known as the Wolff rearrangement to change to an indenecarboxylic acid that is soluble in a basic aqueous solution. Therefore, in combination with the solubility of the base resin in the basic aqueous solution, the exposed portion becomes soluble in the basic aqueous solution, and a positive resist pattern can be provided after development. Since this type of resist is not based on the catalytic chain reaction, it is less affected by the change in the process environment and can be used stably as compared with the above-mentioned chemically amplified resist. Further, in order to stop the solubility of the novolac resin, it is usually necessary to add about 15 to 25 parts by weight of PAC to the resin, but the exposure light source is relatively light such as g-line and i-line. As long as it has a long wavelength, it does not cause a big problem. However, when the exposure light source is changed to an ultraviolet ray such as a KrF excimer laser having a shorter wavelength, in the above resist composition, the resin has low transparency and PA.
The large absorption by C adversely affects the light, and the light does not sufficiently penetrate to the lower part of the resist film. Therefore, it is very difficult to form a rectangular resist pattern.

Furthermore, in order to solve the problem of the conventional chemically amplified resist, a three-component chemically amplified resist has been reported. For example, in combination with polyvinylphenol (PVP), which is one type of phenolic resin,
A three-component chemically amplified resist (R. Hayase et al., J. Photopolym.) Comprising a naphthoquinone diazito compound (as a photoacid generator) and a t-ptoxycarbonylmethylated PVP resin (as a dissolution inhibitor).
Sci. Technol. , 6 (4), 495 (199
3)) or a phenolic resin such as a novolac resin, and a methacrylate ternary copolymer (as a dissolution inhibitor).
And triphenylsulfonium triflate (as a photoacid generator) added to a three-component chemically amplified resist (R.
D. Allen et al., Proc. SPIE, 1925, 2
46 (see 1993)) is known. However, these resists cannot avoid the instability factor due to the chemically amplified resist. That is, in PVP, the transparency of the resin itself is as good as about 60% at the wavelength of 248 nm of the KrF excimer laser, but the dissolution rate of the resin itself in the basic aqueous solution is the fastest among the novolak resins. Since it is more than 3 times faster than that of, it is difficult to bring the dissolution rate to zero even if the above-mentioned dissolution inhibitor is used.

[0009]

The object of the present invention is therefore to solve the problems of the prior art as described above, and to use a basic aqueous solution as a developer.
It is an object of the present invention to provide a novel resist composition having a practical sensitivity and capable of forming a fine pattern without swelling without being affected by environmental changes in the resist process.

Another object of the present invention is to provide a novel resist composition which can be applied to an exposure light source in the deep ultraviolet region such as KrF excimer laser and has excellent dry etching resistance. Another object of the present invention is to provide a method for forming a resist pattern using such a novel resist composition.

[0011]

Means for Solving the Problems As a result of intensive research to solve the above-mentioned problems, the present inventors have determined that the reaction mechanism of a resist composition is a non-chemically amplified type, which has no amplifying effect on the reaction,
A resin having a phenol skeleton used as a base resin is used in combination with a (meth) acrylate-based polymer to adjust it so as to exhibit a dissolution rate within a specific range in a basic aqueous solution, and further specified in this polymer mixture. The present inventors completed the present invention by finding that it is effective to combine the dissolution inhibitor compounds of

In one aspect thereof, the present invention comprises the following components: (a) a film-forming resin having a phenol skeleton and a (meth) acrylate polymer, and 2.3.
When measured in an 8% tetramethylammonium hydroxide aqueous solution, the dissolution rate in the aqueous solution is 100
A polymer mixture soluble in a basic aqueous solution of about 2000 Å / sec; and (b) when a resist composition is prepared by adding it to the polymer mixture, the composition can be insolubilized in the basic aqueous solution. And a dissolution inhibitor compound capable of absorbing and decomposing the composition when the composition is irradiated with imaging radiation, and solubilizing the composition in the basic aqueous solution. A resist composition developable with a basic aqueous solution.

In the resist composition according to the present invention, the (meth) acrylate polymer constituting the polymer mixture is used in a broad sense, and therefore, a homopolymer consisting only of (meth) acrylate monomer. From
It includes various polymers up to a copolymer of such a monomer and any other monomer (including a three-component copolymer and the like). The (meth) acrylate polymer used here preferably has at least one of the repeating units constituting the polymer having an ester group containing a plurality of or polycyclic alicyclic hydrocarbon moieties. Is. The alicyclic hydrocarbon moiety contained in the ester moiety is preferably an adamantyl group, norbornyl group or the like.

When the resist composition of the present invention is applied to a quartz substrate to form a film having a thickness of 1 μm on the substrate, the wavelength of the exposure light source (2) in the deep ultraviolet region is preferable.
The transmittance at 0 to 300 nm) is 30% or more.
The resist composition of the present invention is preferably ethyl lactate,
It is provided in the form of a solution dissolved in a solvent selected from the group consisting of methyl amyl ketone, methyl-3-methoxypropionate, ethyl-3-ethoxypropionate, propylene glycol methyl ether acetate and mixtures thereof. Further, this resist solution may further contain, as an auxiliary solvent, a solvent selected from the group consisting of butyl acetate, γ-butyrolactone, propylene glycol methyl ether and a mixture thereof, if necessary.

In another aspect, the present invention is a method for forming a resist pattern, which comprises the following steps: a resist film formed by applying the resist composition of the present invention onto a substrate to be treated. Selectively exposing the resist composition to an imaging radiation capable of inducing decomposition of the dissolution inhibitor compound of the resist composition, and developing the exposed resist film with a basic aqueous solution. There is a method for forming a resist pattern.

The resist composition and the method for forming a resist pattern according to the present invention have various preferable embodiments, as can be easily understood from the following detailed description. The present invention relates to a resist composition that can be developed with a basic aqueous solution for forming a positive resist pattern on a substrate to be processed. This resist composition is
(A) A resin having a film-forming component and having a phenol skeleton, and an acrylate or methacrylate-based resin,
That is, a polymer mixture soluble in a basic aqueous solution, which is a mixture with a (meth) acrylate-based polymer, and (b)
It comprises a dissolution inhibitor compound which can be insolubilized in a basic aqueous solution by mixing with the polymer mixture, and can be solubilized in the basic aqueous solution when absorbing and decomposing imaging radiation. By constructing the resist composition in this way, non-chemical amplification compatible with deep-ultraviolet light sources by utilizing the high transparency of deep-ultraviolet rays exhibited by (meth) acrylate and the effect of suppressing dissolution in phenolic resins A mold resist can be provided.

In the resist composition of the present invention, the base resin is a film-forming resin having a phenol skeleton. The use of such a resin is particularly useful in terms of its good film-forming property and solubility in a basic aqueous solution.
Resins that can be advantageously used in the practice of the present invention are not limited to those listed below, but are preferably phenol novolac resins, cresol novolac resins, phenol-cresol novolac resins, polyvinylphenol resins, Others.

In the resist composition of the present invention, the above-mentioned phenolic film-forming resin is mixed with a (meth) acrylate polymer to form the first component. It is important when using UV light. This is because the (meth) acrylate polymer has small absorption of light having a wavelength in the deep ultraviolet region. In other words, when using deep UV as the exposure light source,
A structure that does not include an aromatic ring that greatly absorbs light in the deep ultraviolet region or a chromophore having a large molar extinction coefficient such as a conjugated double bond is inevitably required. Further, the transmittance at the exposure wavelength of the resist composition of the present invention comprising a polymer mixture and a dissolution inhibitor compound (value when a resist film having a film thickness of 1 μm is formed on a quartz substrate, hereinafter “transmittance” is It is desirable to consider the structures of the resin and the dissolution inhibitor compound and the addition amount of the dissolution inhibitor so that the value (indicated by the conditions) is 30% or more.

By the way, it has been reported that the (meth) acrylate-based polymer is mixed with the phenol-based resin itself without phase separation, and exhibits a dissolution inhibiting effect (RD Allen, cited above). Et al., Proc. SPI
E, 1925, 246 (1993)). Therefore, also in the practice of the present invention, the ratio of the phenolic resin in the resist composition can be varied within a wide range, provided that when using deep ultraviolet rays as the exposure light source, the ratio is preferably 10 to 10. It is 90% by weight, more preferably 30 to 60% by weight. Also,
The amount of (meth) acrylate polymer added to the phenolic resin can also be varied over a wide range, however,
In the present invention, when a mixture of a phenol resin and a (meth) acrylate-based polymer is measured in a 2.38% tetramethylammonium hydroxide aqueous solution, the dissolution rate (hereinafter, also referred to as ADR) in the aqueous solution is 100 to 100%.
It is necessary to indicate 2000Å / sec. More preferably, the mixing ratio of the phenolic resin and the (meth) acrylate polymer is such that the resulting mixture has an ADR of 200 to 10
It is necessary to adjust to a value in the range of 00Å / sec. Also, the ADR of the phenolic resin itself
Is preferably 100 to 5000 Å / sec, more preferably 500 to 3000 Å / sec. Furthermore, the ADR of the (meth) acrylate-based polymer is preferably 0 to 500.
It is 0Å / sec, more preferably 10 to 500Å / sec.

In order for the (meth) acrylate-based polymer to have some solubility in a basic aqueous solution, a carboxyl group may be added to a part of the ester group contained as a monomer component or a repeating component in the polymer. It is necessary to include an acidic, water-soluble or highly polar functional group represented by a hydroxyl group, an amide group, an oxime group, a ketone group and the like. Therefore, the ester group that can be advantageously introduced as a monomer component into the (meth) acrylate-based polymer is
Acrylic acid, methacrylic acid, 2-hydroxyethyl methacrylate, methacrylamide, acrylonitrile and others. These ester groups may be linear or else cyclic.

More specifically, acidic as described above,
A (meth) acrylate-based polymer containing a monomer component having an ester group containing a water-soluble or highly polar functional group is
As mentioned above, it may be a binary, ternary or higher component copolymer. In particular, control of composition ratio and AD
From the viewpoint of easy adjustment of R, it is recommended to copolymerize the (meth) acrylate monomer with a monomer component having an ester group containing a group having a low polarity such as an alkyl group. Also, instead of such a two-component copolymer, a similar three-component copolymer may be used if the ADR is within the above range. Furthermore, unless the exposure light source is limited to light in the deep ultraviolet region, even if the ester group of the polymer contains a chromophore having a large molar absorption coefficient such as an aromatic ring or a conjugated double bond, the exposure It would not be a problem unless it deteriorates the transparency at the wavelength.

In the case of the (meth) acrylate-based copolymer, an alkyl group-containing ester group is exemplified as the ester group containing a low-polarity group. More specifically, the low polar group to be introduced into such an ester group is not limited to those listed below, but a linear alkyl group typified by a methyl group or an ethyl group, i-propyl group Groups, branched alkyl groups such as t-butyl groups, and cyclic alkyl groups represented by cyclohexyl groups are recommended.

When it is desired to impart excellent dry etching resistance to the resulting resist composition, the ester group as a monomer component of the (meth) acrylate polymer is It is recommended to include multiple or polycyclic alicyclic hydrocarbon moieties. A suitable alicyclic moiety is, for example, a saturated polycyclic alicyclic group represented by an adamantyl group or a norbornyl group.

Furthermore, the molecular weight (weight average molecular weight, Mw) of the (meth) acrylate polymer as described above.
Can be changed within a wide range. Preferably, the molecular weight of such a polymer is in the range of 2000 to 1,000,000, and the ADR to a basic aqueous solution before exposure is used.
In consideration of the above, the range of 3000 to 50000 is more preferable. In addition, the transparency of such a polymer is preferably 50% or more, more preferably 80% or more, at the exposure wavelength when the exposure light source used is deep ultraviolet rays.

Taking the above conditions into consideration, it can be advantageously used in the practice of the present invention (meta).
Some examples of the acrylate-based polymer are listed, but are not limited to the following, but methyl methacrylate-methacrylic acid copolymer, adamantyl methacrylate-methacrylic acid copolymer, norbornyl methacrylate-methacrylic acid copolymer are listed. Acid copolymer, cyclohexyl methacrylate / 2-hydroxyethyl methacrylate / methacrylic acid copolymer, adamantyl methacrylate / 2-hydroxyethyl methacrylate / methacrylic acid copolymer, cyclohexyl methacrylate / methacrylonitrile / methacrylic acid copolymer, adamantyl methacrylate / Methacrylonitrile / methacrylic acid copolymer, norbornyl methacrylate / methacrylonitrile / methacrylic acid copolymer, and the like.

It should be noted that these and other (meth) acrylate polymers can be prepared using polymerization methods commonly used in polymer chemistry. For example, the detailed description of the (meth) acrylate-based polymer of the present invention is omitted in the present specification, but 2,2'-azobisisobutyroyl having a predetermined monomer component as a free radical initiator is omitted. By free radical polymerization in the presence of nitrile (AIBN),
It can be prepared advantageously.

In the resist composition according to the present invention, together with a polymer mixture comprising the above-mentioned (a) phenol resin and (meth) acrylate polymer,
(B) It is essential to use a dissolution inhibitor compound, also known as PAC. The dissolution inhibitor compound used in the present invention can be a compound generally used in this technical field, for example, a naphthoquinonediazide-substituted compound, and its structure is arbitrary. More specifically, the naphthoquinonediazide-substituted compounds that can be advantageously used in the present invention are not limited to those listed below, but are represented by, for example, benzophenone-based compounds, diphenylsulfone-based compounds, and diphenylmethane-based compounds. Substituted compounds obtained by partially or partially esterifying the hydroxyl groups of polyphenolic compounds with naphthoquinonediazide, and the hydroxyl groups of polymer compounds with relatively high transparency in the deep ultraviolet region such as polyvinylphenol. Substituted compounds esterified with naphthoquinonediazide, etc. are included. Further, in this connection, in the case of using deep ultraviolet rays as an exposure light source, for example, in order to provide a resist composition having excellent transparency, the fragrance contained in the core of the dissolution inhibitor compound used is contained. It is recommended to select a structure having a small number of group rings, or to adjust the length of the conjugated system so as to shift the absorption maximum wavelength. In addition,
In the examples described below, as the dissolution inhibiting compound, 2,3,4,4′-tetrahydroxybenzophenone diazonaphthoquinone-4-sulfonyl ester, 2,
3,4,4'-Tetrahydroxybenzophenone diazonaphthoquinone-5-sulfonyl ester, 2,3,4
4'-tetrahydroxybenzophenone diazonaphthoquinone-6-sulfonyl ester, and polyvinylphenol diazonaphthoquinone-6-sulfonyl ester,
It was used.

These dissolution inhibitor compounds can be used in various amounts depending on the structures of the base resin and the (meth) acrylate polymer, the type of exposure light source and other factors. Generally, it is preferably used in an amount of 1 to 50% by weight based on the base resin. Also,
KrF excimer laser (wavelength 248 nm) as exposure light source
When using, it is preferable to use 1 to 20% by weight. Further, if necessary, the sensitivity of the resist composition obtained by adding an appropriate amount of a commonly used sensitizer can be increased.

The resist composition of the present invention is usually used advantageously in the form of a resist solution by dissolving the above-mentioned base resin, (meth) acrylate polymer and dissolution inhibitor compound in an appropriate organic solvent. be able to. The organic solvent useful for preparing the resist solution is recommended to be ethyl lactate, methyl amyl ketone, methyl-3-methoxypropionate, ethyl-3-ethoxypropionate, propylene glycol methyl ether acetate, etc. Not limited. These solvents may be used alone or, if necessary, may be used by mixing two or more kinds of solvents. The amount of these solvents used is not particularly limited, but it is preferable to use an amount sufficient to obtain a viscosity suitable for coating such as spin coating and a desired resist film thickness.

In the resist solution of the present invention, if necessary, an auxiliary solvent may be used in addition to the above-mentioned solvent (particularly referred to as main solvent). The use of an auxiliary solvent is not necessary depending on the solubility of the solute, but when a solute with low solubility is used, it is usually preferable to add it in an amount of 1 to 30% by weight, more preferably 10 to 30% by weight, based on the main solvent. ~ 20% by weight
It is. Examples of useful co-solvents include, but are not limited to, those listed below, butyl acetate, γ-butyrolactone, propylene glycol methyl ether, and the like.

The present invention also provides a method for forming a resist pattern, particularly a positive resist pattern, on a substrate to be processed using the resist composition as described above. The formation of the positive resist pattern of the present invention can usually be carried out as follows. First, the resist composition of the present invention is applied onto a substrate to be processed to form a resist film. The substrate to be processed can be a substrate usually used in semiconductor devices and other devices,
Some examples are silicon substrates, glass substrates,
Nonmagnetic ceramic substrates and the like can be mentioned. Further, if necessary, additional layers such as a silicon oxide layer, a wiring metal layer, an interlayer insulating film, and a magnetic film may be present above these substrates. , Circuits, etc. may be built in. Furthermore, these substrates may be subjected to a hydrophobic treatment according to a conventional method in order to enhance the adhesion of the resist film thereto. Suitable hydrophobizing agents include, for example, 1,1,1,3
3,3-hexamethyldisilazane (HMDS) and the like can be mentioned.

The resist composition can be applied as a resist solution on the substrate to be treated, as described above. The resist solution can be applied by a conventional technique such as spin coating, roll coating, or dip coating, but spin coating is particularly useful. Resist film thickness is about 0.1
The range of up to 200 μm is recommended, but in the case of KrF exposure, the range of 0.1 to 1 μm is recommended. Note that the thickness of the formed resist film can be widely changed depending on factors such as the use of the resist film.

The resist film applied to the substrate is about 60-160 ° C. before it is selectively exposed to imaging radiation.
Pre-bake at a temperature of about 60-120 seconds. This pre-bake can be performed using a heating means commonly used in a resist process. As a suitable heating means, for example, a hot plate, an infrared heating oven,
A microwave heating oven etc. can be mentioned.

Then, the resist film after prebaking is selectively exposed to image forming radiation by a conventional exposure device. Suitable exposure apparatuses are commercially available ultraviolet (far ultraviolet / deep ultraviolet) exposure apparatuses, X-ray exposure apparatuses, electron beam exposure apparatuses, excimer steppers, and the like. As the exposure condition, an appropriate condition can be selected each time. Particularly, in the present invention, as described above, the excimer laser (K of wavelength 248 nm is
rF lasers) can advantageously be used as exposure light sources. In addition, in this specification, if "radiation"
When using the word, it means light from these various light sources, that is, ultraviolet light, far ultraviolet light, deep ultraviolet light, electron beam (EB), X-ray, laser light and the like. As a result of this selective exposure, the dissolution inhibitor compound contained in the exposed region of the resist film absorbs the radiation and decomposes, solubilizing the exposed region in a basic aqueous solution.

After the selective exposure is completed, the exposed resist film is developed with a basic aqueous solution as a developing solution. For this development, a commonly used developing device such as a spin developer, a dip developer, a spray developer or the like can be used. Here, a basic aqueous solution that can be advantageously used as a developer is an aqueous solution of a hydroxide of a metal belonging to Group I or II of the periodic table represented by potassium hydroxide or the like, or a tetraalkylammonium hydroxide. And an aqueous solution of an organic base containing no metal ion. The basic aqueous solution is more preferably tetramethylammonium hydroxide (TMA).
H) and an aqueous solution of tetraethylammonium hydroxide (TEAH). Further, such a basic aqueous solution may contain additives such as a surfactant for improving the developing effect. Further, when a resist containing a small amount of a dissolution inhibitor compound is used in order to ensure transparency of the resist at the exposure wavelength, the dissolution rate (AD
Since R) becomes small, it is possible to form a pattern using a basic aqueous solution which is thinner than that which is usually used. As a result of the development, the exposed region of the resist film is dissolved and removed, and only the unexposed region remains on the substrate as a resist pattern.

[0036]

The resist composition of the present invention comprises (a) (i) a film-forming resin having a phenol skeleton and (ii) (meth).
By mixing the acrylate polymer and (b) the component (a), the resulting mixture can be insolubilized in a basic aqueous solution and, when absorbing imaging radiation, decomposes to make the mixture basic. And a dissolution inhibitor compound capable of being solubilized in an aqueous solution.

By using the components (a) and (b) in combination as described above, it is possible to utilize the high transparency of the (meth) acrylate and the dissolution inhibiting effect on the phenolic resin. The composition
It can be developed with a basic aqueous solution and can be adapted to deep ultraviolet rays. In particular, the second component (ii) of component (a)
As an aromatic ring that greatly absorbs light in the deep ultraviolet region,
A resist composition obtained by selectively using a (meth) acrylate polymer having a structure not containing a chromophore having a large molar absorption coefficient such as a conjugated double bond and adding the component (b) to the polymer 30% transmission of light at the exposure wavelength
As described above, therefore, the resist pattern can be advantageously formed by the deep ultraviolet exposure.

It is widely known in the art to obtain a positive pattern by light exposure in the presence of a dissolution inhibitor. The present invention is also based on the conventional positive photoresist and its function. However, the present invention is distinguished from the conventional photoresist in that it can be used for exposure of shorter wavelength while taking advantage of the advantages of the conventional positive photoresist. That is, the present invention, a transparent (meth) acrylate-based polymer is mixed while maintaining appropriate solubility of the base resin in a basic aqueous solution, to ensure the transparency of the entire resin in the deep ultraviolet region, It is possible to perform exposure using the exposure light source for the area and obtain a rectangular pattern. This resist is a so-called non-chemically amplified type that does not use an amplification reaction for pattern formation, is inexpensive, can utilize the technology established up to now, and is a problem in the chemically amplified resist process. The instability of the environment does not have to be considered at all. Furthermore, since the basic aqueous solution is used for the development, the resist pattern can be formed without swelling.

[0039]

EXAMPLES Next, the present invention will be explained with reference to some examples regarding its resist composition and pattern forming method. It should be understood that the following examples are merely examples and do not limit the scope of the present invention. Example 1 5 g of cresol novolac resin (weight average molecular weight (M
w) = 2700, dissolution rate in 2.38% TMAH aqueous solution (hereinafter, ADR) = 900 Å / sec) and 5 g of methyl methacrylate-methacrylic acid copolymer (composition ratio =)
82:18, Mw = 13500) was dissolved in 25 g of ethyl lactate, and 1.5 g of 2,3,4,4′-tetrahydroxybenzophenone diazonaphthoquinone-5-sulfonyl ester (esterification degree 70%, as PAC). ) Was added and dissolved sufficiently. The resulting resist solution was filtered through a 0.2 μm Teflon ^™ membrane filter, spin-coated on a silicon substrate at 2000 rpm, and baked at 100 ° C. for 90 seconds to obtain a resist coating film having a thickness of 1 μm. The ADR of this resist was 3Å / sec. After exposing this resist coating film by a KrF excimer laser stepper (NA = 0.45), 2.38% TMAH
Develop with aqueous solution and rinse with deionized water for 60 seconds. 2
0.3 μm line and with exposure dose of 00 mJ / cm ²
The space (L / S) pattern could be resolved.

Then, the silicon substrate coated with the resist as described above is housed in a parallel plate type RIE apparatus, and P
μ = 200 W, pressure = 0.02 Torr, argon (Ar)
When Ar sputter etching was carried out under the condition of gas = 50 sccm, it was confirmed by film thickness measurement that the same dry etching resistance as that of Nagase positive resist NPR-820 (manufactured by Nagase & Co., Ltd.) which is a novolak resist was exhibited. Example 2 5 g of cresol novolac resin (Mw = 2700, A
DR = 900Å / sec) and 5 g of adamantyl methacrylate-methacrylic acid copolymer (composition ratio = 78: 22,
Mw = 11000) was dissolved in 25 g of ethyl lactate, and 1.5 g of 2,3,4,4′-tetrahydroxybenzophenone diazonaphthoquinone-5-sulfonyl ester (esterification degree 70%, as PAC) was added. It was sufficiently dissolved. The obtained resist solution was filtered through a 0.2 μm Teflon ^™ membrane filter, and then spin-coated on a silicon substrate at 2300 rpm and the temperature was adjusted to 9 ° C at 100 ° C.
The resist coating film having a thickness of 1 μm was obtained by baking for 0 seconds. The ADR of this resist was 4Å / sec. KrF excimer laser stepper (NA = 0.45)
After being exposed to water, it was developed with a 2.38% TMAH aqueous solution and rinsed with deionized water for 60 seconds. 0.3 μm line and space (L / S) with an exposure dose of 155 mJ / cm ²
The pattern was resolved.

Then, a resist is applied as described above.
The formed silicon substrate was treated with Ar in the same manner as in Example 1 above.
After sputter etching, Nagase Positive Regis
Dry etching resistance equivalent to NPR-820 (described above)
It was confirmed that the product exhibits sex. Example 3 5 g of cresol novolac resin (Mw = 2700, A
DR = 900Å / sec) and 5 g of norbornyl methacrylate
Rate-methacrylic acid copolymer (composition ratio = 80: 20,
Mw = 12500) was dissolved in 25 g of ethyl lactate,
And 3.0 g of polyvinylphenol diazonaphthoquino
-6-sulfonyl ester (esterification degree 40%, P
(As AC) was added and fully dissolved. The cash register obtained
Stroke solution with 0.2 μm Teflon^TMMembrane filter
Filtered at 3000 rpm and spun on a silicon substrate at 3000 rpm
Coat and bake at 100 ° C for 90 seconds to obtain a 1 μm thick layer.
A dist coating film was obtained. The ADR of this resist is 2Å / sec
there were. Apply this resist coating to KrF excimer laser
2.38% TM after exposure with a hopper (NA = 0.45)
Develop with AH aqueous solution, rinse with deionized water for 60 seconds
Was. 160 mJ / cm^TwoExposure amount of 0.28 μm line
The and space (L / S) pattern could be resolved.

Then, a resist is applied as described above.
The formed silicon substrate was treated with Ar in the same manner as in Example 1 above.
After sputter etching, Nagase Positive Regis
Dry etching resistance equivalent to NPR-820 (described above)
It was confirmed that the product exhibits sex. Example 4 5 g of polyvinylphenol resin (Mw = 4600, A
DR = about 5000Å / sec) and 5 g of methyl methacrylate
-Methacrylic acid copolymer (composition ratio = 97: 3, Mw
= 14300) in 25 g of ethyl lactate,
1.7 g of 2,3,4,4'-tetrahydroxybenzo
Phenonediazonaphthoquinone-5-sulfonyl ester
(Esterification degree 70%, as PAC)
Dissolved. The resist solution obtained was applied with a 0.2 μm Tef
Ron^TMAfter filtering with a membrane filter, the silicon substrate
Spin-coated at 2500rpm on top, 90 seconds at 100 ℃
After baking, a resist coating film having a thickness of 1 μm was obtained. This cash register
The strike's ADR was 3Å / sec. This resist coating
Dew with KrF excimer laser stepper (NA = 0.45)
After illuminating, develop with 2.38% TMAH aqueous solution and deionize
Rinse with water for 60 seconds. 200 mJ / cm^TwoExposure of
With 0.3 μm line and space (L / S)
The turn was resolved.

Then, a resist is applied as described above.
The formed silicon substrate was treated with Ar in the same manner as in Example 1 above.
After sputter etching, Nagase Positive Regis
Dry etching resistance equivalent to NPR-820 (described above)
It was confirmed that the product exhibits sex. Example 5 5 g of polyvinylphenol resin (Mw = 4600, A
DR = about 5000Å / sec) and 5 g of cyclohexylme
Tacrylate / 2-hydroxyethyl methacrylate /
Methacrylic acid copolymer (composition ratio = 93: 4: 3, Mw =
11200) is dissolved in 25 g of ethyl lactate, and
1.7 g of 2,3,4,4'-tetrahydroxybenzo
Phenonediazonaphthoquinone-6-sulfonyl ester
(Esterification degree 65%, as PAC)
Dissolved. The resist solution obtained was applied with a 0.2 μm Tef
Ron^TMAfter filtering with a membrane filter, the silicon substrate
Spin coated on top at 2700 rpm for 90 seconds at 100 ° C
After baking, a resist coating film having a thickness of 1 μm was obtained. This cash register
The strike's ADR was 3Å / sec. This resist coating
Dew with KrF excimer laser stepper (NA = 0.45)
After illuminating, develop with 2.38% TMAH aqueous solution and deionize
Rinse with water for 60 seconds. 197 mJ / cm^TwoExposure of
And 0.28 μm line and space (L / S)
The pattern was resolved.

Then, a resist is applied as described above.
The formed silicon substrate was treated with Ar in the same manner as in Example 1 above.
After sputter etching, Nagase Positive Regis
Dry etching resistance equivalent to NPR-820 (described above)
It was confirmed that the product exhibits sex. Example 6 5 g of polyvinylphenol resin (Mw = 4600, A
DR = about 5000Å / sec) and 5g of adamantyl meta
Acrylate / 2-hydroxyethylmethacrylate / me
Tacrylic acid copolymer (composition ratio = 90: 5: 5, Mw = 1)
2300) is dissolved in 25 g of ethyl lactate and 1.
6 g of 2,3,4,4'-tetrahydroxybenzophene
Non-diazonaphthoquinone-6-sulfonyl ester (d
Sterilization degree 65%, added as PAC) and dissolved sufficiently
I let it. The obtained resist solution was added with 0.2 μm Teflon
^TMAfter filtering with a membrane filter, place it on the silicon substrate.
Spin coat at 2700 rpm and spin at 100 ° C for 90 seconds.
To obtain a resist coating film having a thickness of 1 μm. This resist
Had an ADR of 5Å / sec. Kr this resist coating
Exposed with F excimer laser stepper (NA = 0.45)
Then, develop with 2.38% TMAH aqueous solution, deionized water
Rinse for 60 seconds. 205mJ / cm^TwoWith the exposure amount of
0.3 μm line and space (L / S) putter
Was resolved.

Then, a resist is applied as described above.
The formed silicon substrate was treated with Ar in the same manner as in Example 1 above.
After sputter etching, Nagase Positive Regis
Dry etching resistance equivalent to NPR-820 (described above)
It was confirmed that the product exhibits sex. Example 7 5 g of polyvinylphenol resin (Mw = 4300, A
DR = about 3000Å / sec) and 5g adamantyl meta
Crylate-methacrylic acid copolymer (composition ratio = 92:
8, Mw = 11500) dissolved in 25 g of ethyl lactate
And 1.5 g of 2,3,4,4'-tetrahydro
Xybenzophenone diazonaphthoquinone-5-sulfoni
Ruester (degree of esterification 70%, as PAC)
It was dissolved sufficiently. The resulting resist solution is 0.2
μm Teflon^TMAfter filtering with a membrane filter,
Spin-coat on recon substrate at 2700rpm and
Bake at 90 ℃ for 90 seconds to obtain 1μm thick resist coating
Was. The ADR of this resist was 5Å / sec. This
Use a KrF excimer laser stepper (NA =
0.45) and then exposed with 2.38% TMAH aqueous solution.
Developed and rinsed with deionized water for 60 seconds. 186mJ /
cm^Two0.3μm line and space
The (L / S) pattern could be resolved.

Then, a resist is applied as described above.
The formed silicon substrate was treated with Ar in the same manner as in Example 1 above.
After sputter etching, Nagase Positive Regis
Dry etching resistance equivalent to NPR-820 (described above)
It was confirmed that the product exhibits sex. Example 8 5 g of polyvinylphenol resin (Mw = 4600, A
DR = about 5000Å / sec) and 5g of adamantyl meta
Crylate-methacrylic acid copolymer (composition ratio = 93:
7, Mw = 11700) dissolved in 25 g of ethyl lactate
And 1.5 g of 2,3,4,4'-tetrahydro
Xybenzophenone diazonaphthoquinone-5-sulfoni
Ruester (degree of esterification 70%, as PAC)
It was dissolved sufficiently. The resulting resist solution is 0.2
μm Teflon^TMAfter filtering with a membrane filter,
Spin coating on a recon substrate at 2800 rpm and
Bake at 90 ℃ for 90 seconds to obtain 1μm thick resist coating
Was. The ADR of this resist was 5Å / sec. This
Use a KrF excimer laser stepper (NA =
0.45) and then exposed with 2.38% TMAH aqueous solution.
Developed and rinsed with deionized water for 60 seconds. 212mJ /
cm^Two0.3μm line and space
The (L / S) pattern could be resolved.

Then, a resist is applied as described above.
The formed silicon substrate was treated with Ar in the same manner as in Example 1 above.
After sputter etching, Nagase Positive Regis
Dry etching resistance equivalent to NPR-820 (described above)
It was confirmed that the product exhibits sex. Example 9 5 g of polyvinylphenol resin (Mw = 4300, A
DR = about 3000Å / sec) and 5g adamantyl meta
Acrylate / 2-hydroxyethylmethacrylate / me
Tacrylic acid copolymer (composition ratio = 88: 6: 6, Mw = 1
3200) is dissolved in 25 g of ethyl lactate and 1.
65 g of 2,3,4,4'-tetrahydroxybenzoph
Enone diazonaphthoquinone-5-sulfonyl ester
(Esterification degree 70%, as PAC)
Dissolved. The resist solution obtained was applied with a 0.2 μm Tef
Ron^TMAfter filtering with a membrane filter, the silicon substrate
Spin coated on top at 2700 rpm for 90 seconds at 100 ° C
After baking, a resist coating film having a thickness of 1 μm was obtained. This cash register
The strike ADR was 4Å / sec. This resist coating
Dew with KrF excimer laser stepper (NA = 0.45)
After illuminating, develop with 2.38% TMAH aqueous solution and deionize
Rinse with water for 60 seconds. 193mJ / cm^TwoExposure of
And 0.28 μm line and space (L / S)
The pattern was resolved.

Then, a resist is applied as described above.
The formed silicon substrate was treated with Ar in the same manner as in Example 1 above.
After sputter etching, Nagase Positive Regis
Dry etching resistance equivalent to NPR-820 (described above)
It was confirmed that the product exhibits sex. Example 10 5 g of polyvinylphenol resin (Mw = 4600, A
DR = about 5000Å / sec) and 5 g of cyclohexylme
Tacrylate / methacrylonitrile / methacrylic acid copolymer
2 (composition ratio = 88: 5: 7, Mw = 12100)
Dissolve in 5 g of ethyl lactate and add 1.55 g of 2,
3,4,4'-Tetrahydroxybenzophenone diazo
Naphthoquinone-4-sulfonyl ester (degree of esterification
65%, as PAC) was added and fully dissolved. Profit
The resist solution is applied to 0.2 μm Teflon^TMMembrane
2700rp on the silicon substrate after filtering with a filter
spin coat at m and bake at 100 ° C for 90 seconds 1
A resist coating having a thickness of μm was obtained. The ADR of this resist is
It was 4Å / sec. Apply this resist coating to KrF excimer
After exposure with a laser stepper (NA = 0.45), 2.
Develop with 38% TMAH solution and deionized water for 60 seconds
I rinsed. 212 mJ / cm^TwoExposure dose of 0.3 μm
In-and-space (L / S) pattern can be resolved
Was.

Then, a resist is applied as described above.
The formed silicon substrate was treated with Ar in the same manner as in Example 1 above.
After sputter etching, Nagase Positive Regis
Dry etching resistance equivalent to NPR-820 (described above)
It was confirmed that the product exhibits sex. Example 11 5 g of polyvinylphenol resin (Mw = 4300, A
DR = about 3000Å / sec) and 5g adamantyl meta
Crylate / methacrylonitrile / methacrylic acid copolymerization
25 (composition ratio = 85: 7: 8, Mw = 13600)
g of ethyl lactate, and then 1.55 g of 2,3
4,4'-Tetrahydroxybenzophenone diazonaphth
Toquinone-6-sulfonyl ester (esterification degree 70
%, As PAC) was added and fully dissolved. Obtained
Resist solution with 0.2 μm Teflon^TMMembrane
After filtering with a filter, on a silicon substrate at 2700 rpm
Spin coat and bake at 100 ° C for 90 seconds to 1 μm
A thick resist coating film was obtained. The ADR of this resist is 4Å
/ Sec. Apply this resist coating to KrF excimer
2.38 after exposure with the stepper (NA = 0.45)
% TMAH aqueous solution and rinse with deionized water for 60 seconds.
I did 188mJ / cm^TwoWith an exposure dose of 0.3 μm line
・ And-space (L / S) pattern could be resolved.

Then, a resist is applied as described above.
The formed silicon substrate was treated with Ar in the same manner as in Example 1 above.
After sputter etching, Nagase Positive Regis
Dry etching resistance equivalent to NPR-820 (described above)
It was confirmed that the product exhibits sex. Example 12 5 g of cresol novolac resin (Mw = 2300, A
DR = 2000Å / sec) and 5 g of methyl methacrylate
To-methacrylic acid copolymer (composition ratio = 88: 12, Mw
= 12700) in 25 g of ethyl lactate, and
1.5 g of 2,3,4,4'-tetrahydroxybenzo
Phenonediazonaphthoquinone-5-sulfonyl ester
(Esterification degree 70%, as PAC)
Dissolved. The resist solution obtained was applied with a 0.2 μm Tef
Ron^TMAfter filtering with a membrane filter, the silicon substrate
Spin-coated at 2500rpm on top, 90 seconds at 100 ℃
After baking, a resist coating film having a thickness of 1 μm was obtained. This cash register
The strike ADR was 4Å / sec. This resist coating
Dew with KrF excimer laser stepper (NA = 0.45)
After illuminating, develop with 2.38% TMAH aqueous solution and deionize
Rinse with water for 60 seconds. 205mJ / cm^TwoExposure of
With 0.3 μm line and space (L / S)
The turn was resolved.

Then, a resist is applied as described above.
The formed silicon substrate was treated with Ar in the same manner as in Example 1 above.
After sputter etching, Nagase Positive Regis
Dry etching resistance equivalent to NPR-820 (described above)
It was confirmed that the product exhibits sex. Example 13 5 g of cresol novolac resin (Mw = 2300, A
DR = 2000Å / sec) and 5 g of norbornylmethac
Lilate / methacrylonitrile / methacrylic acid copolymer
(Composition ratio = 85: 5: 10, Mw = 12800) is 25
g of ethyl lactate, 1.6 g of 2,3
4,4'-Tetrahydroxybenzophenone diazonaphth
Toquinone-6-sulfonyl ester (esterification degree 65
%, As PAC) was added and fully dissolved. Obtained
Resist solution with 0.2 μm Teflon^TMMembrane
After filtering with a filter, it is 2500 rpm on the silicon substrate.
Spin coat and bake at 100 ° C for 90 seconds to 1 μm
A thick resist coating film was obtained. The ADR of this resist is 4Å
/ Sec. Apply this resist coating to KrF excimer
2.38 after exposure with the stepper (NA = 0.45)
% TMAH aqueous solution and rinse with deionized water for 60 seconds.
I did 210 mJ / cm^TwoWith an exposure dose of 0.3 μm line
・ And-space (L / S) pattern could be resolved.

Then, a resist is applied as described above.
The formed silicon substrate was treated with Ar in the same manner as in Example 1 above.
After sputter etching, Nagase Positive Regis
Dry etching resistance equivalent to NPR-820 (described above)
It was confirmed that the product exhibits sex. Example 14 5 g of cresol novolac resin (Mw = 2300, A
DR = 2000Å / sec) and 5g adamantyl metac
Lilate / methacrylonitrile / methacrylic acid copolymer
(Composition ratio = 80: 10: 10, Mw = 13000) is 2
Dissolve in 5 g of ethyl lactate and add 1.8 g of 2,3
4,4'-Tetrahydroxybenzophenone diazonaphth
Toquinone-5-sulfonyl ester (esterification degree 70
%, As PAC) was added and fully dissolved. Obtained
Resist solution with 0.2 μm Teflon^TMMembrane
After filtering with a filter, it is 2500 rpm on the silicon substrate.
Spin coat and bake at 100 ° C for 90 seconds to 1 μm
A thick resist coating film was obtained. The ADR of this resist is 4Å
/ Sec. Apply this resist coating to KrF excimer
2.38 after exposure with the stepper (NA = 0.45)
% TMAH aqueous solution and rinse with deionized water for 60 seconds.
I did 190 mJ / cm^TwoWith an exposure dose of 0.3 μm line
・ And-space (L / S) pattern could be resolved.

Then, the silicon substrate coated with the resist as described above was subjected to Ar in the same manner as in Example 1 above.
Upon sputter etching, it was confirmed that the same dry etching resistance as that of Nagase positive resist NPR-820 (described above) was exhibited.

[0054]

By using the resist composition according to the present invention, it is possible to form a fine resist pattern which has practical sensitivity and is not affected by environmental changes in the resist process and does not swell. Further, when a plurality of or polycyclic alicyclic groups are introduced into the monomer component of the (meth) acrylate-based polymer of this resist composition, it is possible to obtain a high value in the deep ultraviolet region of the (meth) acrylate-based polymer. It is possible to provide a novel non-chemically amplified resist that utilizes transparency and a dissolution inhibiting effect on a resin having a phenol skeleton and can be applied to a deep-ultraviolet light source and also has dry etching resistance.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H01L 21/027 H01L 21/312 D 21/312 21/30 502R 569E

Claims (7)

[Claims] 1. A composition comprising the following components: (a) a film-forming resin having a phenol skeleton, and a (meth) acrylate polymer, and 2.3.
When measured in an 8% tetramethylammonium hydroxide aqueous solution, the dissolution rate in the aqueous solution is 100
A polymer mixture soluble in a basic aqueous solution of about 2000 Å / sec; and (b) when a resist composition is prepared by adding it to the polymer mixture, the composition can be insolubilized in the basic aqueous solution. And a dissolution inhibitor compound capable of absorbing and decomposing the composition when the composition is irradiated with imaging radiation, and solubilizing the composition in the basic aqueous solution. A resist composition developable with a basic aqueous solution. 2. The meta (acrylate) -based polymer, wherein at least one of the repeating units constituting the polymer has an ester group containing a plurality of or polycyclic alicyclic hydrocarbon moieties. The resist composition according to claim 1, which is characterized. 3. The resist composition according to claim 2, wherein the alicyclic hydrocarbon moiety is an adamantyl group and / or a norbornyl group. 4. A quartz substrate having a film thickness of 1 μm on the substrate.
The resist according to any one of claims 1 to 3, which has a transmittance of 30% or more at a wavelength (200 to 300 nm) of an exposure light source in the deep ultraviolet region when a film of m is formed. Composition. 5. A solution dissolved in a solvent selected from the group consisting of ethyl lactate, methyl amyl ketone, methyl-3-methoxypropionate, ethyl-3-ethoxypropionate, propylene glycol methyl ether acetate and mixtures thereof. The resist composition according to claim 1, which is in the form of 6. The resist composition according to claim 5, further comprising a solvent selected from the group consisting of butyl acetate, γ-butyrolactone, propylene glycol methyl ether and a mixture thereof as an auxiliary solvent. 7. The following steps: The resist composition according to claim 1 is applied onto a substrate to be treated, and the formed resist film is capable of inducing decomposition of a dissolution inhibitor compound of the resist composition. A method for forming a resist pattern, which comprises selectively exposing the resist film after exposure to radiation and developing the resist film after exposure with a basic aqueous solution.