JPH06242606A - Positive radiation-sensitive mixture - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To provide a novel, highly radiation-sensitive mixture in the short wavelength UV region for semiconductor structure production, which has a stable acid latent image and can be developed with an alkaline aqueous solution. [Structure] a) a binder insoluble in water and soluble in an aqueous alkaline solution as essential components, b) a compound having at least one bond capable of being cleaved by an acid, c) a compound capable of generating an acid by irradiation, and d) a base. Positive radiation-sensitive mixture, characterized in that it contains a soluble sulfonium compound.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a resist material which is sensitive to actinic radiation, and more particularly to a positive-working radiation-sensitive mixture.

[0002]

Radiation-sensitive mixtures are known per se. Commercially, especially positive-working mixtures have been found to contain poly (4) in addition to o-quinonediazide.
-Hydroxystyrene) or novolac as a resist material containing a binder soluble in an aqueous alkaline solution. However, the sensitivity and resolution of these systems for radiation, especially short wavelength radiation, is insufficient. Since novolak has a high intrinsic absorption in the UV-2 region (220 to 300 nm), it is deep UV (220 to 30).
0 nm) is unsuitable as a binder in a single layer resist material. On the other hand, poly (hydroxystyrene)
(PHS) is characterized by having more advantageous absorption characteristics in the UV region, higher thermal stability and good dry etching resistance.

PH as a binder with acid-sensitive side groups
Positive-working radiation-sensitive mixtures for UV-2 using S are known, for example from USP 4,491,628. It is also known that the radiation sensitivity of a radiation-sensitive mixture is increased by releasing the acid by the action of radiation and then adding a compound in which the acid catalyzes a secondary reaction. Examples of such a compound which forms a strong acid by the action of an acid include diazonium, phosphonium salt, sulfonium salt and iodonium salt, nitrobenzyl ester, phenolic methanesulfonate, diazo compound and halogen compound, bissulfonylmethane compound, bissulfonyl. There are diazomethane compounds.

H. Reschelt et al., “Important process parameters for acetal-based deep UV photoresists” [Advances in Resist Technology and Processing IX, Anthony E. et al.
November, Editing, Proc. SPIE 1672, 3
3-45 (1992)], a positive radiation-sensitive mixture comprising a PHS copolymer, an acid-generating compound and an N, O-acetal-based oligomolecular inhibitor is described. The problem with this photosensitive mixture is the latent latent image (latent saeurebild).
It is very sensitive to the instability of. The problem of acid latent image instability is a fundamental problem with new resist materials that work by the principle of chemical amplification. This problem,
In the professional literature, for example, "Chemically Amplified Resist Airborne Chemical Contaminants" S.I. A. McDonald et al., Progress in Resist Technology and Processing VIII, Hiroshiito, Editor, Proc. SPIE 1466,
2-12 (1991). L. Schlegel's work has shown the problem of diffusion in chemically amplified resist materials (L. Schlegel et al., Ja.
p.Journ. of Applied Physics Series 5, 1991 International Microprocess Conference Research Presentation, 175-180
page). The average moving radius of the acid acting as a catalyst is 248.
In a high resolution resist for nm, it has the same size as the structure to be resolved. J. Nakamura is Jap.Journ.of
Applied Physics (Vol. 30, No. 10, 1991 1)
Jan. 2619-2625) describes a method by which the diffusion length and diffusion constant in chemically amplified resist materials can be investigated. This fundamental physical phenomenon limits resolution in chemically amplified systems that are particularly sensitive to changes in the latent image of the acid because of the low active energy barrier. H. Reschelt et al. [Advances in Resist Technology and Processing IX, Anthony E. November, edit,
Proc. SPIE1672, 33 to 45 (199
2)] has the following unfavorable properties when no additives are used due to diffusion problems. 1) The resolution is only up to 0.5 μm. 2) High resolution can only be achieved by undesired deflection of linearity. 3) Exposure latitude is very small. 4) Very low dwell time stability between exposure and subsequent post-exposure bake and significant line width loss (slimming) in the unexposed resist areas.

[0005]

The object of the present invention is to provide a novel, highly radiation-sensitive mixture in the short-wave UV region for the production of semiconductor structures which can be developed with aqueous alkaline solutions and which has a stable acid latent image. Is to provide.

The above-mentioned objects are, as essential components, a) a binder insoluble in water and soluble in an aqueous alkaline solution, b) a compound having at least one bond cleavable by an acid, and c) a compound forming an acid by irradiation. And d) a radiation-sensitive mixture comprising a basic sulfonium compound. Each of the above components a) to d) is used as a mixture of one or more. General formulas I to IV)

[0007]

[Chemical 2] ^{(Wherein, R 1, R 2, R} 3 , independently of one another, C ₁ ~
C ₁₈ alkyl, aryl, heteroaryl, or aryl mono-, di- or tri-substituted by alkyl, aryl, halogen, alkoxy, phenoxy, thiophenol, phenylsulfonyl, phenylsulfenyl, Y is [CH ₂ ] _n where n = 0 or 1 means O or S, and R ⁴ and R ⁵ are
C ₁ -C ₄ represents alkyl, alkoxy or halogen, R ^6, R ⁷ is C ₁ -C ₄ represents alkyl, alkoxy, halogen, n is 5 or 6, X is, pK _B values -3 It is a basic anion that is +5. The basic sulfonium compound (1) is preferably used.

The content of basic sulfonium compound will be 0.01 to 2.00 molar equivalents relative to the maximum amount of acid that can theoretically be formed from compound c).

All sulfonium compounds which meet the following criteria are suitable: 1) Sufficient solubility in resist 2) Sufficient thermal stability 3) Sufficient basic counterion Particularly preferred compounds are those in which R ¹ , R ² and R ³ are mutually Independently, methyl, ethyl, propyl, isopropyl, butyl, phenyl, biphenyl, tolyl, xylyl, chlorophenyl, bromophenyl, methoxyphenyl, ethoxyphenyl, propyloxyphenyl, butyloxyphenyl, tert. -Butyloxyphenyl, phenoxyphenyl, thiophenoxyphenyl, phenylsulfonylphenyl, Y means [CH ₂ ] _n , O or S in which n = 0 or 1, and R ⁴ and R ⁵ are C ₁
To C ₄ alkyl, methoxy, ethoxy, chlorine or bromine, and R ⁶ and R ⁷ are C _{1 to} C ₄ alkyl, methoxy,
Represents ethoxy, chlorine or bromine, n is n = 5 or 6
In it, X is X = hydroxyl, X = OR (R = C 1 ~C 4 alkyl), (alcoholate) X = OCOR (R = C 1 ~C 10 alkyl, aryl, alkylaryl), X = OCOO ^- ( Carbonates) of the general formulas I) to IV).

Sulfonium salts are well known in the technical literature and are of great technical importance as photochemical polymerization catalysts. The use of sulfonium salts in radiation-sensitive mixtures is described, for example, in USP 4,491,628. The use of onium salts in resist materials is described by Krivero in Org. Coatings and Appl. Polym. Sci.
8, pages 65-69 (1985). Synthetic and photochemical properties are described in Klibero's overview "Cationic Polymerization-
Iodonium salt and sulfonium salt photoinitiators ",
J. V. Klibero, Progress in Polymer Science 62, Springer Press, Berlin Heidelberg 1984. An intensive mechanistic study on the acid formation mechanism of sulfonium salt compounds is described in J. L. Dr. and N.N. P. By Hackers, Journal of American Chemical Society 1990, 112, 60
Published in 04-6015.

An attempt to produce sulfonium hydroxide from silver sulfonium halide by silver oxide is reported in Journal of American Chemical Society 73 (1951), page 1967. These compounds are unstable oils that decompose at room temperature, already giving off a sulphide odor.

It has now been found, surprisingly, that the literature reports on the instability of triphenylsulfonium hydroxide do not apply to solutions of these compounds in polar and non-polar solvents.

The present inventors have further developed a method for producing an arbitrary sulfonium hydroxide, which prevents contamination of the compound with metal ions. This method is of great importance for the use of the radiation-sensitive mixtures according to the invention in semiconductor technology. Ion exchange chromatography is used in polar or non-polar eluents. A preferred resin is an amberlyst type resin having a quaternary ammonium group. In principle, the ion exchange resin can be converted into the basic form by any tetraalkylammonium solution with a basic counterion. Tetramethylammonium hydroxide is particularly suitable. Water, alcohol,
Tetrahydrofuran or a non-polar organic solvent is preferred. Particularly, methanol or ethanol is preferable.

The corresponding halides are in principle used for the preparation of the sulfonium hydroxide, but other anions, such as complex metal fluorides, tetrafluoroborates, hexafluorophosphates, are also possible. is there. The sulfonium salt is dissolved in a small amount of eluent and loaded onto the exchanger column. The elution rate, which also depends on the size and loading of the column, is essentially lower than when exchanging the strong electrolyte in ion exchange chromatography. This is because equilibration to the theoretical standard of the column requires more time than if the compound had strongly dissociated in the eluent.

The base content in the elution volume is measured by titration and is in agreement with the theoretical value. The titration curve of triphenylsulfonium hydroxide in water / methanol containing 0.1 n HCl shows clear buffer properties in the pH = 7 region. Therefore, triphenylsulfonium hydroxide is an amphoteric molecule in solution, rather than the expected strong electrolyte.

An exchange rate of 99.8% is achieved by the above method. Other properties of the basic sulfonium salt solution are U
It can be studied by V spectroscopy. The maximum position and the maximum extinction coefficient are unchanged compared to the non-basic sulfonium salt used. Therefore, this anion has little effect on the absorption characteristics of the sulfonium chromophore.

Subsequently, the eluent can be replaced by another suitable solvent by evaporation under reduced pressure.

By this method, a solution having a specific sulfonium hydroxide concentration in a solvent suitable for resist formulation can be obtained.

Titration of the base content at various time intervals proves that the sulfonium hydroxide in solution is constant.

As already mentioned above, the process according to the invention for basic sulfonium salts is not restricted to the production of hydroxides. By ion-exchange chromatography, may be the anion depending on having any kind of pK _B value, also to produce other basic and non-basic solutions. However, all other basic and non-basic compounds can be obtained from the hydroxide particularly easily by simply adding the conjugate acid. 1) [Ph ₃ S] ⁺ (OH) ⁻ + HO-aryl → [P
h ₃ S] ^{+ -} O- aryl ^{_{2) [Ph 3 S] +}} (OH) - + HO-CO-R → [P
^{_{h 3 S] + - O-}} CO-R 3) [Ph 3 S] + (OH) - + HO-SO 2 -R →
[Ph ₃ S] ⁺ -O-SO ₂ -R Using the above method, by using an appropriately prepared ion exchange column or by back titration of the hydroxide solution with the corresponding conjugate acid, A sulfonium salt with any anion can be obtained very easily.

The technical advantages of the above process are: 1) the ability to work without metal ions, 2) the production of sulfonium salts which are unstable in the isolated form and which can be used in radiation-sensitive mixtures, 3 3.) It is possible to produce sulfonium salts that cannot be produced in pure form and use them in radiation-sensitive mixtures.

The process according to the invention for producing a basic sulfonium hydroxide solution is particularly suitable for producing a sulfonium acetate solution by ester hydrolysis. Propylene glycol monomethyl ether acetate (P
GMEA) is the preferred solvent for resist technology.
Replacing the eluent of the basic sulfonium hydroxide solution with PGMEA results in ester cleavage of the solvent and is complete in a short time.

The basic anion undergoes an acid-base reaction with the phenolic binder in the resist matrix to a polyphenolate anion, which neutralizes the acid that diffuses into the unexposed areas.

Surprisingly, weakly basic anions such as acetate or common carboxylate anions are also suitable, buffering the acid diffusing into the unexposed areas and catalyzing the acetal hydrolysis. Does not work.

As a result, the acid latent image is stabilized, the resolution is improved by lithography, the stop time stability is increased, and the processing width (exposure latitude) is increased.

The addition of a basic compound to the radiation-sensitive mixture to be chemically amplified and processed neutralizes not only the acid whose base diffuses into the unexposed areas, but also the acid present in the exposed areas. So it is inconsistent in itself. However, in order to have a difference in solubility, an acid is necessary for the catalytic reaction.

The technical advantage of basic sulfonium hydroxides over non-photoactive basic additives is that they are photoactive in their own right and neutralize themselves in the exposed areas. This allows large amounts of base to be added to the resist without significant loss of radiation sensitivity.

As the binder, a binder containing a phenolic hydroxyl group is suitable, and poly (hydroxystyrene) is used.
Has high thermal stability and good resistance to etching agents.
It is particularly preferable because it has high UV transparency in the 8 nm region. A particularly suitable binder is poly (4-hydroxystyrene) and its copolymers with alkyl-substituted 4-hydroxystyrene. In particular, the copolymers poly [4-hydroxystyrene-co-4-hydroxy-3-methylstyrene] and poly [4-hydroxystyrene-co-4
-Hydroxy-3,5-dimethylstyrene] is preferred. The monomer ratio can be varied between 10% and 90%, but the monomer ratio of 2:
1 to 1: 2 are particularly suitable, and their solubility in aqueous alkaline developers is of paramount importance for the polymer matrix. The molecular weight M _W may be 3000 to 100,000 daltons, but is preferably 8000 to 30,000 and the dispersity needs to be 2 or less.

The hydrophilicity of the resist matrix is adjusted by mixing poly (4-hydroxystyrene) with another phenolic binder. To mix with PHS,
Alkyl-substituted polyvinylphenol, especially poly (4
-Hydroxy-3-methylstyrene) or novolacs are also suitable.

As the compound having at least one bond capable of being cleaved by an acid, a compound having at least one C--O--C or C--N--C bond is preferably used. As such, general formula V) (In the formula, R ¹ may be a C ₁ -C ₄ alkylene group, R ² means a C ₁ -C ₄ alkyl group, R ³ means a C ₁ -C ₁₀ alkyl group or an aryl group, and X is Groups -CO-,-
It means one of O—CO— or NH—CO, and n means an integer greater than 1. Compounds of) are preferred.

Chemically important are the poly-N, O-acetals formed by the acid-catalyzed reactive acetal exchange of the corresponding aldehyde dimethyl acetals and the corresponding alcohol components. The degree of condensation and the molecular weight distribution are adjusted by the polycondensation conditions.

As the acid generating compound, a diazonium salt,
Iodonium salts, sulfonium salts, halides, ortho-quinonediazide-sulfonic acid esters are preferred. The above onium salts are generally in the form of their organic solvent soluble salts, often tetrafluoroborates, hexafluorophosphates, hexafluoroantimonates or hexafluoroarsenates or sulfonic acids. Used as a salt, for example trifluoromethyl sulfonate or hexafluoropropyl sulfonate. Among the halogen compounds, triazine, oxazole, oxadiazole, thiazole, and 2-pyrone substituted with a trichloromethyl group and / or a tribromomethyl group are preferable. In addition, halogenated, especially chlorinated and brominated aromatic compounds are also suitable as acid generators.

Compounds which generate sulfonic acid, have good thermal stability and show advantageous absorption properties in the 248 nm region are preferred.

Since the acid generation efficiency is high and the transparency in the DUV region is high, a phenolic sulfonic acid ester, bissulfonylmethane or general formula VI) is used. Particularly preferred is bissulfonyldiazomethane (wherein R and R'independently of each other represent an alkyl, cycloalkyl, aryl, or heteroaryl group).

Particularly suitable are sulfonium-sulfonates such as triarylsulfonium-sulfonates and bis (4-chlorophenylsulfonyl) diazomethane. The sulfonium-sulfonate can be obtained, for example, by adding sulfonic acid to a basic sulfonium salt solution, and specific examples thereof include triphenylsulfonium-sulfonate. Examples of the sulfonic acid used here include alkyl sulfonic acid, partially fluorinated or fully fluorinated alkyl sulfonic acid, aryl sulfonic acid,
And aryl sulfonic acids substituted with halogen, alkyl or alkoxy, nitro, cyano or halogenalkyl groups. The content of compound c) is 1 to 10% by weight of the solid content. Mixtures of one or more photoactive compounds may have advantageous properties in the resist.

The mixture according to the invention consisting of components a) to d) is dissolved in an organic solvent, the solids content being generally in the range from 5 to 40% by weight. Preferred solvents are aliphatic ketones, ethers and esters and any mixtures thereof. Particularly preferred solvents are alkylene glycol-monoalkyl ethers such as 1-methoxy-2-propanol, and alkylene glycol alkyl ether esters such as 1-methoxy-2-propanol-acetate (PGMEA).

In addition, other additives such as adhesion promoters, crosslinkers, colorants and plasticizers can be added.

If desired, small amounts of sensitizers can be added to render the radiant acid generator sensitive from the long wavelength UV to the visible range. Polycyclic aromatic compounds such as pyrene and perylene are preferred for this, but dyes which act as sensitizers can also be used.

The photoresist solution containing the radiation-sensitive mixture according to the invention is generally a layer of 0.1 to 5 μm, preferably 0.5 to 1.5 μm, on a suitable substrate, for example a surface-oxidized silicon wafer. It is spin-coated on top, dried (eg at a temperature of 70-130 ° C.) and imagewise illuminated through a photomask with a suitable light source. Short-wave UV radiation (far UV) with a wavelength of 200 to 300 nm is particularly suitable as the light source. A particularly suitable light source is
It is an excimer laser of KrF (248 nm). After irradiating so as to project an image, at a temperature of 40 to 90 ° C, 180 to 3
A baking process (post-exposure baking) is performed for 0 seconds. 6 at 60 ° C
A baking treatment for 0 seconds is preferable. The photoresist is developed with an alkaline developer, which is preferably free of metal ions, such as aqueous tetramethylammonium hydroxide. When using a tetramethylammonium hydroxide aqueous solution, it is preferable that the concentration thereof is 1.0 to 4.0% by weight.
The resolution is in the range of less than 0.5 micron. The irradiation energy required for the radiation-sensitive mixture of the present invention is generally 5
~ 100 mJ / cm ² .

The developed resist structure is optionally post-cured. This typically heats the resist structure on a hot plate to a temperature below the Fliesstemperatur, followed by a xenon-mercury vapor lamp (200-250).
Irradiate the entire surface in the (nm region). This post-curing causes the resist structure to crosslink and become generally flow-resistant (Fliessstandigkeit) up to temperatures of 200 ° C.

A preferred use of the radiation-sensitive mixture according to the invention is as a resist material for the production of integrated circuits or various electronic components. The recording material produced from this mixture can then be used as a mask in subsequent steps. Thereafter, for example, the layer support is etched, ions are embedded in the layer support, or the metal is separated. In addition, the radiation-sensitive mixture according to the invention is also suitable for producing lithographic printing plates. Propylene Glycol of Triphenylsulfonium Hydroxide
Lumonomethyl ether acetate (PGMEA) solution
Manufacturing method Amberlyst A-2 on a column with a length of 55 cm and an inner diameter of 5 cm
6 700 g are filled in chloride form. For this purpose, the resin is dispersed in methanol and poured into a column. To 3 liters of a 0.54n solution of tetramethylammonium hydroxide is added 3 liters of methanol. The prepared column is converted to the hydroxide form with this alkaline solution.

The column is rinsed with 3 liters of methanol until the pH value is neutral.

30 mmol of triphenylsulfonium bromide
(10.29 g) is dissolved in a small amount of methanol and added on the column. The elution rate is 30 ml / h. Elution is recorded potentiometrically or by UV absorption. 0.
The base content is measured by titrating with 1 n HCl. Bromine ion test with silver nitrate is negative. From the content measurement, it was found that the exchange rate was 99.8%. Methanol was evaporated under reduced pressure in a rotary evaporator, followed by a final triphenylsulfonium hydroxide (TP
SH) until a 0.1 nPGMEA solution was obtained.
Replace with MEA.

This freshly prepared TPSH solution is used to formulate the radiation-sensitive mixture. The base content of this solution was rechecked after 24 hours and the titration curve shows acetate buffer. TPSH is completely converted to triphenylsulfonium acetate.

Replacing methanol with propylene glycol monomethyl ether does not change the TPSH concentration in the solution.

By the same method, a solution of tri (4-methylphenyl) sulfonium hydroxide and tri (4-chlorophenyl) sulfonium hydroxide was prepared.

[0047]

EXAMPLES The following raw materials were used in the examples described below. Polymer A: Poly [4-hydroxystyrene-co-4-hydroxy-
3-Methylstyrene] (2: 1 copolymer) M _W = 14000 g / mol, M _N = 7000 g / mol Optical density (248 nm) = 0.18 / μm ⁻¹ Poly-N, O-acetal B: R ₁ = n-propyl R ₂ = ethylene R ₃ = aryl X = O-CO- n: M W = 2500 mol / g M W / M n> 2.5 photoactive compound C: bis (4-chlorophenyl sulfonyl) Diazomethane Photoactive compound D: Bis (4-chlorophenylsulfonyl) methane Photoactive compound E: Triphenylsulfonium triflate Solvent: 1-Methoxy-propylene glycol-2-acetate (PGMEA) The composition of the test radiation-sensitive mixture is parts by weight. Show. Example 1
~ 8 A radiation sensitive mixture having the following composition was prepared. 1.40 parts by weight Polymer A 0.70 parts by weight Poly-N, O-acetal B 0.04 parts by weight Photoactive compound C 8.00 parts by weight PGMEA This solution was filtered with a filter having a pore size of 0.2 μm, It was spin coated as a uniform layer of 1 μm thickness on a silicon wafer pretreated with hexamethyldisilazane as an adhesion promoter. The wafer was dried (soft-baked) on a hot plate at 120 ° C. for 60 seconds and subsequently structured for imaging. Irradiation was carried out by a Canon excimer stepper with a numerical aperture of 0.37, with 248 nm KrF excimer laser irradiation, using test masks with various structural dimensions. The dwell time between irradiation and the subsequent baking step (post-exposure baking PEB) and development was an important process parameter and was kept below 2 minutes in these irradiation experiments unless otherwise indicated. The post-exposure baking was normally performed at 60 ° C. for 60 seconds. The developed wafer was developed by immersing it in a 2.38 wt% tetramethylammonium hydroxide solution (0.265n). The lithographic results were evaluated by the achieved 1: 1 resolution of lines and grooves (line / space structure).

In the stop time test, the time between irradiation and PEB was changed and development was performed immediately after PEB. The results were evaluated by the line width loss (slimming) of the resulting structure relative to the structure width obtained at the same dose and without stopping time.

These examples are summarized in the table. However,
PAC in the table means a photoactive compound.

[0050]

[Table 1] Example 9 A radiation sensitive mixture having the following composition is prepared. 2.00 parts by weight Phenolic OH groups were added to tert. −
Polyhydroxystyrene esterified up to 40% with butylcarbonyl group 0.05 parts by weight Photoactive polymer E 8.00 parts by weight PGMEA 50% 0.1 mmol / g TPSH as a PGMEA solution (based on the amount of compound E in the resist) 50
This solution was filtered through a filter having a pore size of 0.2 μm and spin-coated as a uniform layer of 1 μm thickness on a silicon wafer pretreated with hexamethyldisilazane as an adhesion promoter. The wafer was dried (soft-baked) on a hot plate at 120 ° C. for 60 seconds and subsequently structured for imaging. Irradiation was carried out by a Canon excimer stepper with a numerical aperture of 0.37, with 248 nm KrF excimer laser irradiation, using test masks with various structural dimensions. The dwell time between irradiation and the subsequent baking step (post-exposure baking PEB) and development was an important process parameter and was kept below 2 minutes in these irradiation experiments unless otherwise indicated. Post-exposure bake was typically performed at 90 ° C. for 60 seconds. Development of the irradiated wafer was performed by immersing it in a tetramethylammonium hydroxide solution (0.15n). As a result of evaluating the resolution of the resist material in the same manner as in the above example,
It was also found to be improved. Example 10 A radiation sensitive mixture having the following composition was prepared. 2.00 parts by weight Polyhydroxystyrene in which phenolic OH groups are etherified to 40% with silanol groups 0.05 parts by weight Photoactive polymer E 8.00 parts by weight PGMEA 50% 0.1 mmol / g TPSH as a PGMEA solution ( 50 based on the amount of compound E in the resist
This solution was filtered through a filter having a pore size of 0.2 μm and spin-coated as a uniform layer of 1 μm thickness on a silicon wafer pretreated with hexamethyldisilazane as an adhesion promoter. The wafer was dried (soft-baked) on a hot plate at 120 ° C. for 60 seconds and subsequently structured for imaging. Irradiation was carried out by a Canon excimer stepper with a numerical aperture of 0.37, with 248 nm KrF excimer laser irradiation, using test masks with various structural dimensions. The dwell time between irradiation and the subsequent baking step (post-exposure baking PEB) and development is an important process parameter and is kept below 2 minutes in these irradiation experiments unless otherwise indicated. Post-exposure baking was typically performed at 70 ° C. for 60 seconds. Development of the irradiated wafer was performed by immersing it in a tetramethylammonium hydroxide solution (0.15n). As a result of evaluating the resolution of the resist material in the same manner as in the above example,
It was also found to be improved. Example 11 A radiation sensitive mixture having the following composition was prepared. 2.00 parts by weight Polyhydroxystyrene in which phenolic OH groups are etherified to 40% with tetrahydropyranyl groups 0.05 parts by weight Photoactive polymer E 8.00 parts by weight PGMEA 50% 0.1 mmol / g as PGMEA solution TPSH (50 against the amount of compound E in the resist)
This solution was filtered through a filter having a pore size of 0.2 μm and spin-coated as a uniform layer of 1 μm thickness on a silicon wafer pretreated with hexamethyldisilazane as an adhesion promoter. The wafer was dried (soft-baked) on a hot plate at 120 ° C. for 60 seconds and subsequently structured for imaging. Irradiation was carried out by a Canon excimer stepper with a numerical aperture of 0.37, with 248 nm KrF excimer laser irradiation, using test masks with various structural dimensions. The dwell time between irradiation and the subsequent baking step (post-exposure baking PEB) and development was an important process parameter and was kept below 2 minutes in these irradiation experiments unless otherwise indicated. Post-exposure baking was typically performed at 70 ° C. for 60 seconds. Development of the irradiated wafer was performed by immersing it in a tetramethylammonium hydroxide solution (0.15n). As a result of evaluating the resolution of the resist material in the same manner as in the above example,
It was also found to be improved. Example 12 A radiation sensitive mixture having the following composition was prepared. 2.00 parts by weight Phenolic OH groups were added to tert. −
Polyhydroxystyrene etherified to 40% with butyl ester group 0.05 parts by weight Photoactive polymer E 8.00 parts by weight PGMEA 50% 0.1 mmol / g TPSH as a solution of PGMEA (based on the amount of compound E in the resist) 50
This solution was filtered through a filter having a pore size of 0.2 μm and spin-coated as a uniform layer of 1 μm thickness on a silicon wafer pretreated with hexamethyldisilazane as an adhesion promoter. The wafer was dried (soft-baked) on a hot plate at 120 ° C. for 60 seconds and subsequently structured for imaging. Irradiation was carried out by a Canon excimer stepper with a numerical aperture of 0.37, with 248 nm KrF excimer laser irradiation, using test masks with various structural dimensions. The dwell time between irradiation and the subsequent baking step (post-exposure baking PEB) and development was an important process parameter and was kept below 2 minutes in these irradiation experiments unless otherwise indicated. Post-exposure bake was typically performed at 90 ° C. for 60 seconds. Development of the irradiated wafer is performed by immersing it in a tetramethylammonium hydroxide solution (0.15n). As a result of evaluating the resolution of the resist material in the same manner as in the above example, it was found that the same improvement was obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication H01L 21/027 (72) Inventor Yoshiaki Kinoshita 2-18-22 Shin-Sayama, Sayama City, Saitama Prefecture No. (72) Inventor Susumu Natsumi 10-10 Yamazaki Building, 2-10 Nakahara-cho, Kawagoe City, Saitama Prefecture No. 306 (72) Inventor Muniratuna, Padmanavan, Tokorozawa, Saitama Prefecture, 876, 2 Tokorozawa Corpus C Building 403 ( 72) Inventor Hiroshi Okazaki 22-1-909 Renjakucho, Kawagoe-shi, Saitama Prefecture (72) Inventor Gen 5-7-30 Kosenba-cho, Kawagoe-shi, Saitama Prefecture (72) Inventor Ralf, Damel Rhode Island, USA , Conventry, Wood, Estates, Wood, Cove, Drive, 70

Claims (18)

[Claims] 1. As essential components, a) a binder insoluble in water and soluble in an aqueous alkali solution, b) a compound having at least one bond cleavable by an acid, c) a compound capable of generating an acid by irradiation, and d) A positive-working radiation-sensitive mixture, characterized in that it comprises a basic sulfonium compound. 2. A compound b) which can be cleaved by an acid, C--O--.
The positive-working radiation-sensitive mixture according to claim 1, which is a compound having at least one C or C—N—C bond. 3. The content d of the basic sulfonium compound is
Positive-working radiation-sensitive mixture according to claim 1 or 2, characterized in that it is from 0.01 to 2.00 molar equivalents relative to the maximum amount of acid that can theoretically be formed from compound c). 4. The basic sulfonium compound d) has the general formula I to IV: ^{(Wherein, R 1, R 2, R} 3 , independently of one another, C ₁ ~
C ₁₈ means alkyl, aryl, heteroaryl, or alkyl, alkylaryl, aryl,
Halogen, alkoxy, phenoxy, thiophenol,
Phenylsulfonyl, means an aryl mono-, di- or tri-substituted by phenylsulfenyl, Y is
n = 0 or 1 means [CH ₂ ] _n , O or S, R ⁴ and R ⁵ represent C _{1 to} C ₄ alkyl, alkoxy or halogen, and R ⁶ and R ⁷ represent C _{1 to} C ₄ represents alkyl, alkoxy, halogen, n is 5 or 6, X is, pK _B value is basic anion is -3 + 5. 2.) The compound of claim 1)
The positive-working radiation-sensitive mixture according to any one of 3 to 3. 5. The basic sulfonium compound d) is a compound represented by formulas I to IV (wherein R ¹ , R ² and R ³ are independently of each other,
Methyl, ethyl, propyl, isopropyl, butyl, phenyl, benzylbiphenyl, tolyl, xylyl, chlorophenyl, bromophenyl, methoxyphenyl, ethoxyphenyl, propyloxyphenyl, butyloxyphenyl, tert. -Butyloxyphenyl, phenoxyphenyl, thiophenoxyphenyl, or phenylsulfonylphenyl, wherein Y is n = 0 or 1
[CH ₂ ] _n , O or S, wherein R ⁴ , R ⁵
Represents C ₁ -C ₄ alkyl, methoxy, ethoxy, chlorine or bromine, R ⁶ and R ⁷ represent C ₁ -C ₄ alkyl, methoxy, ethoxy, chlorine or bromine, and n is n = 5 or 6. , X is X = hydroxyl group, OR (R = C ₁ -C ₄ alkyl), (alcoholate) OCOR (R = C ₁ -C ₁₀ alkyl, aryl, alkylaryl), or OCOO ⁻ (carbonate). 2.) The compound of claim 1)
The positive-working radiation-sensitive mixture according to any one of 4 to 4. 6. Positive-working radiation-sensitive mixture according to claim 1, characterized in that the binder a) contains phenolic hydroxyl groups. 7. A binder according to claim 1, wherein the binder a) is polyvinylphenol, alkyl-substituted polyvinylphenol or a copolymer thereof.
The positive-working radiation-sensitive mixture according to the item. 8. The positive mold according to claim 1, wherein the binder a) further comprises one other type of phenolic binder in addition to polyvinylphenol. Radiation-sensitive mixture. 9. A compound of the general formula V (In the formula, R ¹ may be a C ₁ -C ₄ alkylene group, R ² means a C ₁ -C ₄ alkyl group, R ³ means a C ₁ -C ₁₀ alkyl group or an aryl group, and X is Groups -CO-,-
It means one of O—CO— or NH—CO, and n means an integer greater than 1. ) The positive-working radiation-sensitive mixture according to any one of claims 1 to 8, characterized in that 10. Positive-working radiation-sensitive mixture according to claim 1, characterized in that it contains compound b) in a concentration of 1 to 60% by weight. 11. The positive-working radiation-sensitive mixture according to claim 1, wherein the compound c) forms a sulfonic acid by photolysis. 12. The compound c) according to claim 1, wherein a sulfonium-sulfonate produced by adding a sulfonic acid to a basic sulfonium salt solution is used. Positive radiation-sensitive mixture. 13. A sulphonic acid substituted by an alkylsulphonic acid, a partially or fully fluorinated alkylsulphonic acid, an arylsulphonic acid, a halogen, an alkyl or alkoxy, a nitro, a cyano or a halogenalkyl group. Positive-working radiation-sensitive mixture according to claim 12, characterized in that it is an arylsulphonic acid. 14. The compound c) has the general formula VI (Wherein R and R'represent an alkyl, cycloalkyl, aryl or heteroaryl group), alpha,
Positive-working radiation-sensitive mixture according to any one of claims 1 to 13, characterized in that it is an alpha-bis-sulfonyldiazomethane derivative. 15. The positive-working radiation-sensitive according to claim 1, wherein the compound c) is an alpha, alpha-bissulfonylmethane derivative or a phenolic sulfonic acid ester. blend. 16. The compound c) is present in the mixture in a concentration of up to 1-10% by weight.
15. The positive-working radiation-sensitive mixture according to any one of 15. 17. A radiation-sensitive recording material comprising a layer support and a radiation-sensitive layer, said radiation-sensitive layer comprising a radiation-sensitive mixture according to any one of claims 1-16. Recording material characterized by. 18. A method for producing basic and non-basic sulfonium compounds by ion exchange chromatography, comprising: a) the exchange resin being an amberlyst having a quaternary ammonium group, and b) the exchange resin being a metal. Converting to the OH form with an ion-free polar or non-polar eluent, and c) the eluent is water or a polar or non-polar organic solvent.