JP2008290990A - Method for producing alicyclic saturated hydrocarbon compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an alicyclic saturated hydrocarbon compound, which further improves the transmittance of alicyclic saturated hydrocarbon compound which is suitable as a liquid for immersion exposure and has excellent transmittance at 193 nm. <P>SOLUTION: The method for producing an alicyclic saturated hydrocarbon having transmittance at a wavelength of 193 nm of ≥99% per 1 mm of the optical path length comprises successively passing at least one alicyclic saturated hydrocarbon compound selected from 1,1'-bicyclohexyl, exo-tetrahydrodicyclopentadiene and trans-decahydronaphthalene through two or more columns packed with an adsorbent composed of at least one oxide selected from alumina, silica alumina and zeolite. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing an alicyclic saturated hydrocarbon compound, and more particularly to a production method capable of reducing absorbance for use in an immersion exposure apparatus or an immersion exposure method.

Stepper-type or step-and-scan projection exposure that transfers a reticle pattern as a photomask to each shot area on a photoresist-coated wafer via a projection optical system when manufacturing semiconductor elements, etc. The device is in use.
The theoretical limit value of the resolution of the projection optical system provided in the projection exposure apparatus becomes higher as the exposure wavelength used is shorter and the numerical aperture of the projection optical system is larger. For this reason, with the miniaturization of integrated circuits, the exposure wavelength, which is the wavelength of radiation used in the projection exposure apparatus, has become shorter year by year, and the numerical aperture of the projection optical system has also increased.
As described above, in the field of manufacturing semiconductor devices and the like, conventionally, the exposure light source has been shortened in wavelength and the numerical aperture has been increased to meet the demand for miniaturization of an integrated circuit. Currently, an ArF excimer laser (wavelength: 193 nm) is used as an exposure light source. ) Using 1L1S (1: 1 line and space) half pitch 90 nm node is under study. However, it is said that it is difficult to achieve the next generation half pitch 65 nm node or 45 nm node, which is further miniaturized, only by using an ArF excimer laser. Thus, for these next-generation technologies, the use of short-wavelength light sources such as F ₂ excimer laser (wavelength 157 nm), EUV (wavelength 13 nm), etc. is being studied. However, the use of these light sources is technically difficult and is still difficult to use.

By the way, in the above exposure technique, a photoresist film is formed on the surface of the wafer to be exposed, and a pattern is transferred to the photoresist film. In a conventional projection exposure apparatus, a space in which a wafer is placed is filled with air or nitrogen having a refractive index of 1.
Theoretically, the limit value of resolution and the depth of focus are increased to 1 / n and n times, respectively, by filling a liquid of refractive index n between the lens of the projection exposure apparatus and the wafer and setting an appropriate optical system. Is possible. For example, in the ArF process, when water is used as the liquid filled between the lens and the wafer, the refractive index n of water having a wavelength of 193 nm in water is n = 1.44. In comparison, it is theoretically possible to design an optical system with a resolution of 69.4% and a focal depth of 144%.
A projection exposure method that can reduce the effective wavelength of radiation for exposure in this way and transfer a finer pattern is called immersion exposure, and in future lithography miniaturization, especially lithography in units of several tens of nm, It is considered an essential technology.

In the immersion exposure method, the applicant of the present invention has a refractive index larger than that of pure water conventionally used as a liquid for immersion exposure, and has excellent transparency, and a photoresist film or its upper layer film component (especially hydrophilic layer). Liquid) that can prevent elution and dissolution of the active ingredient), suppress the defects during resist pattern generation without eroding the lens, and can form patterns with better resolution and depth of focus when used as an immersion liquid. As a result of investigating various compounds for the purpose of providing immersion exposure liquids, we have filed applications for alicyclic saturated hydrocarbon compounds that have low absorption in the far ultraviolet region and have a high refractive index suitable as immersion exposure liquids. (Patent Document 1).
However, when an alicyclic saturated hydrocarbon compound synthesized by a known method or available on the market is used as a liquid for immersion exposure, it generally has a large absorption in the far ultraviolet region. There are cases where problems such as degradation of throughput due to decrease in throughput due to reduction, optical image defocus and distortion due to refractive index fluctuation due to heat generation of liquid due to light absorption of liquid, degradation of pattern shape, etc. due to defocus of optical image there were.

Absorption in the far-ultraviolet region is a compound having a carbon-carbon unsaturated bond or an aromatic ring, which has a large influence on the transmittance even in a very small amount, and a compound having a functional group such as a carbonyl group or a hydroxyl group as impurities. The alicyclic saturated hydrocarbon compound is considered to be slightly present, and therefore includes a plurality of sulfuric acid washing treatment steps having different treatment temperatures, and at least the final sulfuric acid washing treatment step has a treatment temperature higher than that of the washing treatment step. The present inventors have already proposed a method characterized by processing at a processing temperature lower than the processing temperature of the previous processing step (Patent Document 2). Moreover, the method of refine | purifying an alicyclic saturated hydrocarbon compound using an adsorbent is disclosed (patent documents 3 and 4).
However, even with the above purification method, there are problems that the transmittance at 193 nm of the alicyclic saturated hydrocarbon compound is not sufficiently improved, and the number of steps is complicated. For example, in the method of Patent Document 3, the transmittance at 193 nm cannot be increased to 99% or more per 1 mm of the optical path length. Further, the method of Patent Document 4 has a problem that two kinds of adsorbents must be used to increase the transmittance. Furthermore, the methods of Patent Document 3 and Patent Document 4 have a problem that when an attempt is made to industrially manufacture a liquid for immersion exposure, the liquid cannot be processed efficiently and with a small amount of adsorbent.
WO2005 / 114711 Japanese Patent Application No. 2006-329265 WO2005 / 119371 WO2006 / 115268

  The present invention has been made in order to cope with such problems, and a production method capable of further improving the transmittance of an alicyclic saturated hydrocarbon compound suitable as an immersion exposure liquid having excellent transmittance at 193 nm. The purpose is to provide.

As a result of various investigations regarding efficient removal of impurities contained in the alicyclic saturated hydrocarbon compound, trace amounts of impurities can be efficiently removed by sequentially passing through two or more columns. As a result, it was found that a liquid for immersion exposure having a high transmittance at 193 nm was obtained, and the invention was completed.
That is, the method for producing an alicyclic saturated hydrocarbon compound according to the present invention is a production method in which the transmittance at a wavelength of 193 nm is 99% or more per 1 mm of the optical path length of the liquid, and the alicyclic saturated hydrocarbon used as a raw material It includes a step of sequentially passing the compound through two or more columns filled with an adsorbent.
The alicyclic saturated hydrocarbon compound is at least one alicyclic saturated hydrocarbon compound selected from 1,1′-bicyclohexyl, exo-tetrahydrodicyclopentadiene, and trans-decahydronaphthalene. It is characterized by.
The adsorbent is at least one oxide selected from alumina, silica alumina, and zeolite.
In particular, when the alicyclic saturated hydrocarbon compound is 1,1′-bicyclohexyl or exo-tetrahydrodicyclopentadiene, the adsorbent is at least one oxide selected from silica alumina and zeolite. It is characterized by.
The alicyclic saturated hydrocarbon compound is trans-decahydronaphthalene.
In the production method of the present invention, the purity of the alicyclic saturated hydrocarbon compound as a raw material by gas chromatography is 99% by mass or more.

The production method of the present invention can efficiently remove a very small amount of impurities by sequentially passing the raw material alicyclic saturated hydrocarbon compound through two or more columns. Since the adsorption equilibrium value of each impurity with respect to the adsorbent is different, the purification per unit adsorbent is more effective when the purification is performed through two or more columns than the purification means through which only one column is passed. This is thought to be because the amount can be increased. As a result, a liquid for immersion exposure having a transmittance at a wavelength of 193 nm of 99% or more per 1 mm of the optical path length of the liquid can be efficiently produced.
By using this liquid, heat generation due to light absorption can be suppressed, and problems such as optical image defocus and distortion due to refractive index fluctuations, resolution due to optical image defocus, and degradation of pattern shape can be suppressed. be able to.

The alicyclic saturated hydrocarbon compound produced by the production method of the present invention has a light transmittance at a wavelength of 193 nm of 99% or more per 1 mm of the optical path length of the liquid.
Between the transmittance T per 1 mm of the optical path length and the absorbance A per 1 cm of the optical path length,

T (%) = 100 × 10 ^{−0.1 A}

Therefore, a transmittance of 99% or more per 1 mm of the optical path length corresponds to an absorbance of 0.0437 or less per 1 cm of the optical path length. When the transmittance is within the above range, heat generation due to light absorption can be suppressed, and problems such as optical image defocus and distortion due to refractive index fluctuations, resolution due to optical image defocus, degradation of pattern shape, etc. Can be suppressed.

The column that can be used in the production method of the present invention is a container in which an adsorbent is packed. Preferably, it is a cylindrical container having openings at both ends, and is a container in which an alicyclic saturated hydrocarbon compound as a raw material is introduced from one opening and the purified product can be recovered from the other opening.
In the present invention, two or more columns are sequentially passed through the column for purification. For purification, even if two or more columns are directly connected in series, the liquid is collected by passing through the first column and then charged into the second column in order, and then collected for each column. You may refine | purify by the method of repeating.
In the present invention, the same single column is not purified by being passed multiple times, but one column is only passed once.

  It is preferable to prepare and use two or more unused columns. The shape of the column and the type of adsorbent may be the same or different. It is preferable to use two or more columns packed with the same adsorbent because of easy quality control of the adsorbent. This is because when a plurality of adsorbents are used, as much effort is required for quality control as the number of adsorbent types.

The adsorbent that can be used in the present invention is alumina, silica alumina, zeolite, or an oxide obtained by combining these.
Alumina is an oxide whose composition formula is represented by Al ₂ O ₃ . Silica alumina is called amorphous silica-alumina, and zeolite is called crystalline aluminosilicate.
When the adsorbent that can be used in the present invention is evaluated by the following method, the ratio between the absorbance after contacting with the adsorbent and the absorbance of the alicyclic saturated hydrocarbon compound before contacting with the adsorbent is 1.1 or less can be used.
<Evaluation method>
30 ml of alicyclic saturated hydrocarbon compound of 0.0437 or less per 1 cm of optical path length of liquid at a wavelength of 193 nm is put in a glass container, and 1.5 g of adsorbent is added to this alicyclic saturated hydrocarbon compound to form nitrogen. Let stand at 25 ° C. for 72 hours under atmosphere. The absorbance (A) before contact with the adsorbent and the absorbance (B) after contact are measured with light having a wavelength of 193 nm, and the absorbance ratio (B / A) is calculated.

By employing the method of the present invention, the amount of adsorbent can be reduced. For example, the amount of adsorbent required for producing 100 ml of an alicyclic saturated hydrocarbon compound having a transmittance of 99% / mm or more can be less than 20 g.
Also, for use in the present invention, the adsorbent is preferably calcined before use at a temperature of 200 to 500 ° C, preferably 250 to 500 ° C. In the case of firing below 200 ° C. or unfired, the above evaluation value cannot be achieved.

  In the purification method using the adsorbent, the alicyclic saturated hydrocarbon compound used as a raw material preferably has a purity of 99% by mass or more according to the gas chromatography method before being charged into the column. Purity by gas chromatography can be measured with an Agilent 6890 gas chromatography system, column (TC1701), carrier gas (helium), and detector (TCD).

In the purification method using the adsorbent, the alicyclic saturated hydrocarbon compound used as a raw material is at least one fat selected from 1,1′-bicyclohexyl, exo-tetrahydrodicyclopentadiene, and trans-decahydronaphthalene. A cyclic saturated hydrocarbon compound is preferable because the transmittance is easily set to 99% / mm or more by the production method of the present invention.
The combination of the alicyclic saturated hydrocarbon compound and the adsorbent is such that when the alicyclic saturated hydrocarbon compound is 1,1′-bicyclohexyl or exo-tetrahydrodicyclopentadiene, the adsorbent is silica alumina, zeolite, or these This mixture is preferable because the impurities contained in the alicyclic hydrocarbon compound as a raw material can be efficiently removed.
Further, when the alicyclic saturated hydrocarbon compound is trans-decahydronaphthalene, the impurities contained in the alicyclic hydrocarbon compound from which alumina, silica alumina, zeolite, or a mixture thereof is used as a raw material can be efficiently removed. It is preferable because it can be removed.

Since the alicyclic saturated hydrocarbon compound produced by the method of the present invention has little elution of volatile impurities, particularly the resist components, the optical properties are recovered with good reproducibility by performing recovery and purification by a simple method. Can be reused.
As a purification method in the case of reusing, a method such as washing with water, acid washing (sulfuric acid washing), alkali washing, precision distillation, purification using an appropriate filter (packed column), filtration, etc., and the above-described method of the present invention Examples thereof include a purification method or a method using a combination of these purification methods. Among these, it is preferable to carry out purification by water washing treatment, alkali washing, acid washing, precision distillation, oxide adsorption or a combination of these purification methods.
The above alkali cleaning removes the acid generated by the exposure eluted in the immersion exposure liquid, the acid cleaning removes the basic components in the resist eluted in the immersion exposure liquid, and the water washing process elutes in the immersion exposure liquid. It is effective for removal of a photoacid generator, a basic additive, and an eluate such as an acid generated during exposure in the resist film.
The method for producing an alicyclic saturated hydrocarbon compound disclosed in the present invention is also effective in the above recovery and purification, and is caused by the decomposition of an acid-dissociable protecting group in a resin or irradiation of a liquid with radiation by this method. Since removal of impurities having carbon and carbon unsaturated bonds, which are photoreaction products, can be effectively performed, fluctuations in transmittance can be prevented.
In addition, precision distillation can be performed at the time of purification. Precision distillation is effective for removing low-volatile compounds among the above-mentioned additives, and is effective for removing hydrophobic components generated by decomposition of protective groups in the resist during exposure.

The photoresist film or the photoresist film on which the upper layer film for immersion is formed is irradiated with radiation through a mask having a predetermined pattern using the alicyclic saturated hydrocarbon compound produced in the present invention as a medium, and then developed. Thus, a resist pattern can be formed.
The radiation used for immersion exposure depends on the photoresist film used and the combination of the photoresist film and the upper layer film for immersion, for example, visible rays; ultraviolet rays such as g rays and i rays; Various types of radiation such as ultraviolet rays; X-rays such as synchrotron radiation; and charged particle beams such as electron beams can be selectively used. In particular, an ArF excimer laser (wavelength 193 nm) or a KrF excimer laser (wavelength 248 nm) is preferable.

Examples are shown below. In addition, in a glove box with a nitrogen atmosphere controlled to 0.5 ppm or less, liquids were sampled in cells with an optical path length of 1 cm and 2 cm with a lid made of polytetrafluoroethylene, and JASCO-V7100 manufactured by JASCO Corporation was used. The absorbance was measured using the cell containing the liquid as a sample and air as a reference, and the difference between the two was defined as the absorbance per 1 cm. The measurement temperature is 23 ° C. Based on this value, the transmittance per mm was calculated according to Lambert Beer's law. If the transmitted light intensity of the sample is l ₀ and the transmitted light intensity of the reference is l, the absorbance is expressed as log ₁₀ (l ₀ / l). The values in the table shown in each example are values obtained by correcting the reflection of the cells by calculation.

The following adsorbents were used. Each adsorbent was calcined at 500 ° C. for 3 hours, and then packed into a glass column having a column diameter of 31 mmΦ and a column length of 150 mm to prepare a plurality of columns.
Silica alumina: N633L, manufactured by JGC
Zeolite-1: HSZ-341NHA manufactured by Tosoh Corporation
Zeolite-2: manufactured by Tosoh Corporation, F-9
Alumina: Sumitomo Chemical Co., Ltd., KHD-12

Example 1
Under a nitrogen atmosphere, adsorption filtration was performed using a column packed with 4 g of silica alumina to 100 ml of 1,1′-bicyclohexyl having a GC purity of 99.9% by mass. After the adsorption filtration, the transmittance at 193 nm was measured and found to be 95.50% / mm.
The liquid after the adsorption filtration was subjected to adsorption filtration using a column newly filled with 1 g of silica alumina. When the transmittance at 193 nm was measured after passing through the second silica-alumina column, it was 99.54% / mm.
Further, 5 g of silica alumina was used in total to produce 100 ml of 1,1′-bicyclohexyl having a transmittance of 99% / mm or more by this operation.

Example 2
Under a nitrogen atmosphere, adsorption filtration was performed using a column packed with 5 g of zeolite-1 with respect to 100 ml of 1,1′-bicyclohexyl having a purity of 99.9% by mass. After the adsorption filtration, the transmittance at 193 nm was measured and found to be 98.69% / mm.
The liquid after the adsorption filtration was subjected to adsorption filtration using a column newly filled with 5 g of zeolite-1. After passing through the second zeolite-1 column, the transmittance at 193 nm was measured and found to be 99.38% / mm.
In addition, a total of 10 g of zeolite-1 was used to produce 100 ml of 1,1′-bicyclohexyl having a transmittance of 99% / mm or more by this operation.

Example 3
Under a nitrogen atmosphere, adsorption filtration was performed using a column packed with 5 g of zeolite-2 with respect to 100 ml of 1,1′-bicyclohexyl having a purity of 99.9% by mass. After the adsorption filtration, the transmittance at 193 nm was measured and found to be 95.75% / mm.
The liquid after the adsorption filtration was subjected to adsorption filtration using a column newly filled with 2 g of zeolite-2. When the transmittance at 193 nm was measured after passing through the second zeolite-2 column, it was 99.54% / mm.
In addition, a total of 7 g of zeolite-2 was used to produce 100 ml of 1,1′-bicyclohexyl having a transmittance of 99% / mm or more by this operation.

Example 4
Under a nitrogen atmosphere, adsorption filtration was performed using a column packed with 5 g of silica alumina to 100 ml of exo-tetrahydrodicyclopentadiene having a purity of 99.9% by mass. After the adsorption filtration, the transmittance at 193 nm was measured and found to be 95.73% / mm.
The liquid after the adsorption filtration was subjected to adsorption filtration using a column newly filled with 5 g of silica alumina. When the transmittance at 193 nm was measured after passing through the second silica-alumina column, it was 99.14% / mm.
In addition, a total of 10 g of silica alumina was used to produce 100 ml of exo-tetrahydrodicyclopentadiene having a transmittance of 99% / mm or more by this operation.

Example 5
Under a nitrogen atmosphere, adsorption filtration was performed using a column packed with 4 g of zeolite-1 to 100 ml of exo-tetrahydrodicyclopentadiene having a purity of 99.9% by mass. After this adsorption filtration, the transmittance at 193 nm was measured and found to be 97.61% / mm.
The liquid after the adsorption filtration was subjected to adsorption filtration using a column newly filled with 4 g of zeolite-1. After passing through the second zeolite-1 column, the transmittance at 193 nm was measured and found to be 99.75% / mm.
In addition, a total of 8 g of zeolite-1 was used to produce 100 ml of exo-tetrahydrodicyclopentadiene having a transmittance of 99% / mm or more by this operation.

Example 6
Under a nitrogen atmosphere, adsorption filtration was performed using a column packed with 5 g of zeolite-1 with respect to 100 ml of trans-decahydronaphthalene having a purity of 99.9% by mass. After the adsorption filtration, the transmittance at 193 nm was measured and found to be 91.20% / mm.
The liquid after the adsorption filtration was subjected to adsorption filtration using a column newly filled with 5 g of zeolite-1. After passing through the second column, the transmittance at 193 nm was measured and found to be 98.70% / mm.
Further, this liquid was subjected to adsorption filtration using a column newly filled with 5 g of zeolite-1. When the transmittance at 193 nm was measured after passing through the third column, it was 99.11% / mm.
Moreover, in order to produce 100 ml of trans-decahydronaphthalene having a transmittance of 99% / mm or more by this operation, a total of 15 g of zeolite-1 was used.

Example 7
In a nitrogen atmosphere, adsorption filtration was performed using a column packed with 5 g of alumina with respect to 100 ml of trans-decahydronaphthalene having a purity of 99.9% by mass. After the adsorption filtration, the transmittance at 193 nm was measured and found to be 91.40% / mm.
The liquid after the adsorption filtration was subjected to adsorption filtration using a column newly filled with 5 g of alumina. After passing through the second column, the transmittance at 193 nm was measured and found to be 98.50% / mm.
Further, this liquid was subjected to adsorption filtration using a column newly filled with 5 g of alumina. When the transmittance at 193 nm was measured after passing through the third column, it was 99.07% / mm.
In addition, a total of 15 g of alumina was used to produce 100 ml of trans-decahydronaphthalene having a transmittance of 99% / mm or more by this operation.

Comparative Example 1
Under a nitrogen atmosphere, adsorption filtration was performed using a column packed with 20 g of silica alumina to 100 ml of 1,1′-bicyclohexyl having a purity of 99.9% by mass. After the adsorption filtration, the transmittance at 193 nm was measured and found to be 97.74% / mm.

Comparative Example 2
Under a nitrogen atmosphere, adsorption filtration was performed using a column packed with 40 g of silica alumina to 100 ml of 1,1′-bicyclohexyl having a purity of 99.9% by mass. After this adsorption filtration, the transmittance at 193 nm was measured and found to be 98.77% / mm.

Comparative Example 3
The liquid after adsorption filtration obtained in Comparative Example 2 was subjected to adsorption filtration using the same column. After the second adsorption filtration, the transmittance at 193 nm was measured and found to be 98.61% / mm.
Furthermore, this liquid was subjected to adsorption filtration using the same column. After the third adsorption filtration, the transmittance at 193 nm was measured and found to be 98.45% / mm.

Comparative Example 4
Under a nitrogen atmosphere, adsorption filtration was performed using a column packed with 40 g of silica alumina to 100 ml of exo-tetrahydrodicyclopentadiene having a purity of 99.9% by mass. After the adsorption filtration, the transmittance at 193 nm was measured and found to be 98.17% / mm.

From Examples 1 to 7, 1,1′-bicyclohexyl, exo-tetrahydrodicyclopentadiene and trans-decahydronaphthalene are passed through two or more columns packed with silica alumina, zeolite or alumina as an adsorbent. Thus, it was found that the transmittance at 193 nm was 99% / mm or more.
When combined with the results of Comparative Examples 1 to 4, an immersion exposure liquid having a transmittance of 99% / mm or more cannot be obtained by passing only one column. In addition, even if the same column is passed a plurality of times, an immersion exposure liquid having a transmittance of 99% / mm or more cannot be obtained, and these methods are not preferable because only the amount of adsorbent used is increased. The transmittance can be improved efficiently by passing through more than one column.

  In the method for producing an alicyclic saturated hydrocarbon compound of the present invention, the transmittance at 193 nm is 99 by sequentially passing the alicyclic saturated hydrocarbon compound as a raw material through two or more columns filled with an adsorbent. % / Mm or more of the alicyclic saturated hydrocarbon compound for immersion exposure. Therefore, it can be used very suitably as a liquid used in immersion exposure, which is an essential technique for manufacturing semiconductor devices that are expected to be further miniaturized in the future.

Claims (7)

A method for producing an alicyclic saturated hydrocarbon compound having a transmittance at a wavelength of 193 nm of 99% or more per 1 mm of an optical path length of a liquid,
The manufacturing method of the alicyclic saturated hydrocarbon compound characterized by including the process of making the alicyclic saturated hydrocarbon compound used as a raw material pass through two or more columns filled with adsorption agent in order.   The alicyclic saturated hydrocarbon compound is at least one alicyclic saturated hydrocarbon compound selected from 1,1′-bicyclohexyl, exo-tetrahydrodicyclopentadiene, and trans-decahydronaphthalene. The method for producing an alicyclic saturated hydrocarbon compound according to claim 1.   The method for producing an alicyclic saturated hydrocarbon compound according to claim 1 or 2, wherein the adsorbent is at least one oxide selected from alumina, silica alumina, and zeolite.   4. The alicyclic saturated hydrocarbon compound is 1,1′-bicyclohexyl, and the adsorbent is at least one oxide selected from silica alumina and zeolite. The manufacturing method of alicyclic saturated hydrocarbon compound of description.   4. The alicyclic saturated hydrocarbon compound is exo-tetrahydrodicyclopentadiene, and the adsorbent is at least one oxide selected from silica alumina and zeolite. Of producing an alicyclic saturated hydrocarbon compound.   The method for producing an alicyclic saturated hydrocarbon compound according to claim 2, wherein the alicyclic saturated hydrocarbon compound is trans-decahydronaphthalene.   The alicyclic saturated hydrocarbon compound according to any one of claims 1 to 6, wherein the purity of the alicyclic saturated hydrocarbon compound as the raw material by gas chromatography is 99% by mass or more. Manufacturing method.