JPH1129331A - Production of optical member of synthetic quartz glass, and optical member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing glass high in transmittance and resistance to ultraviolet ray by ejecting a mixture of an organosilicon compound and a halide compound of silicon, oxygen-containing gas and hydrogen-containing gas from a gas burner for combustion, depositing quartz glass on a target, transparentizing the glass, and forming a quartz glass ingot. SOLUTION: This method ejects a mixture of an organosilicon compound and a halide compound of silicon, oxygen-containing gas and hydrogen-containing gas from a gas burner of multi-tubular structure, provided with a first tube 1 at the center, and second to 7th tubes concentrically arranged around the first tube 1. An organosilicon compound, e.g. siloxane, and halide compound of silicon, e.g. chloride SiCl4 or fluoride SiF4 are ejected from the first tube 1, and oxygen-containing and hydrogen-containing gases are ejected from the second to 7th tubes alternately, wherein flow rate and linear velocity of the gas ejected from each tube are controlled independently, to produce quartz glass. It is preferable that the quartz glass contains chlorine at 10 wt.ppm or less, fluorine at 100 wt.ppm or less, Na at 10 wt.ppb or less, and hydrogen atoms at 2×10<17> to 4×10<18> /cm<3> after heat-treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing quartz glass, and more particularly to a method for producing a synthetic quartz glass optical member used for an ultraviolet laser in general, and a synthetic quartz glass optical member for ultraviolet produced by the method. It is about.

[0002]

2. Description of the Related Art Conventionally, in an optical lithography technique for exposing and transferring a fine pattern of an integrated circuit onto a wafer such as silicon, an exposure apparatus called a stepper is used. The light source of this stepper has been changed from g-line (436 nm) to i-line (365n) with the recent high integration of LSI.
m), KrF (248 nm) and ArF (193 nm).
nm) Excimer lasers are being shortened in wavelength.

In general, optical glass used as a lens material constituting an illumination optical system or a projection optical system of a stepper has a low light transmittance in a wavelength region shorter than i-line. It has been proposed to use a single crystal of a fluorine compound such as synthetic quartz glass or CaF ₂ (fluorite). The optical system mounted on the stepper is composed of a combination of many lenses. Even if the amount of decrease in transmittance per lens is small, it is integrated by the number of lenses used, and the amount of light on the wafer surface Leads to a decline. For this reason, high transmittance is required for the lens material. Further, as the wavelength used becomes shorter, the imaging performance becomes extremely poor even with a very small unevenness of the refractive index distribution.

As described above, quartz glass used as an optical material for ultraviolet lithography is required to have high transmittance of ultraviolet light and high homogeneity of refractive index. However, commercially available synthetic quartz glass is insufficient in quality, including homogeneity and UV resistance, and cannot be used in precision optical instruments as described above. For this reason,
Until now, secondary treatment for homogenization and improvement of UV resistance by heat treatment in pressurized hydrogen gas have been attempted.

[0005] In these methods, quartz glass is once synthesized and then subjected to a secondary treatment in order to improve optical performance.

[0006]

When light in the ultraviolet region acts on quartz glass, 5.8 eV called an E 'center is generated.
It is known that an absorption band appears, and the transmittance in the ultraviolet region is significantly reduced. Then, chlorine present in the quartz glass can be a precursor of the 5.8 eV absorption band.

Therefore, first, in order not to reduce the transmittance of quartz glass in the ultraviolet region, chlorine present in quartz glass must be reduced as much as possible. Therefore, synthesis of quartz glass using an organosilicon compound has recently been performed. However, these conventional techniques do not consider the carbon remaining in the organosilicon compound in the glass at all, and do not show any grounds that chlorine is not mixed in the member.

[0008] Silicon tetrachloride, which has been conventionally used for the synthesis of quartz glass, contains 30 to 15% in the obtained quartz glass member.
Since about 0 ppm of chlorine is contained, it is inferior in terms of UV resistance as compared with quartz glass from which chlorine is completely eliminated. However, since the chlorine contained in the raw material releases metal impurities present in the synthesis atmosphere as chlorides to the outside of the system, the resulting member is very high in purity.
As described above, most of the conventional quartz glass has relatively good durability but slightly lower transmittance, or has a relatively good transmittance but slightly lower durability.

Next, hydrogen molecules in quartz glass will be described. When light in the ultraviolet region acts on the quartz glass, an absorption band of 5.8 eV called an E 'center appears, and the transmittance in the ultraviolet region is significantly reduced. Here, when hydrogen molecules are present, the hydrogen molecules are terminated at the E ′ center, and the decrease in the transmittance of quartz glass in the ultraviolet region can be drastically reduced.

[0010] Hydrogen molecules in quartz glass have the effect of significantly improving the durability to ultraviolet light. However, conventionally, in order to introduce hydrogen molecules into quartz glass, there is a problem in that once the quartz glass is synthesized, heat treatment must be performed again. That is, in this method, heat is applied at least twice until hydrogen molecules are introduced. Therefore, there are problems such as a decrease in productivity and an increase in cost of the final product. In addition, there is also a problem that a new absorption band and a luminescence band are generated due to contamination with impurities and exposure to a reducing atmosphere by heat treatment under pressure at a high temperature.

In addition, in recent years, as the diameter of a lens used in the photolithography technology has increased, it has been necessary to uniformly introduce hydrogen molecules into a large-diameter quartz glass optical member by secondary processing.
Considering the diffusion coefficient, it has a considerably long time. Further, when considering the use as a lens for ultraviolet lithography, there is a problem that the hydrogen molecule concentration at the center where the energy density is the highest is smaller than that at the periphery.

The present invention solves these problems, and a method for producing an optically homogeneous, synthetic quartz glass having high transmittance and durability to ultraviolet light, in which a decrease in transmittance due to ultraviolet irradiation is suppressed, and a synthetic quartz glass optical device. An object is to provide a member.

[0013]

Accordingly, in the present invention, intensive studies have been made on a technique for eliminating chlorine in quartz glass and maintaining a high transmittance. As a result, when a mixture of an organosilicon compound and a halogen compound of silicon, preferably a fluorine compound, is used as a raw material, a quartz glass satisfying both ultraviolet durability and transmittance can be obtained. : 15 was found to be most effective for chlorine, Na and carbon.

Accordingly, the present invention provides a synthetic method in which a silicon compound, an oxygen-containing gas, and a hydrogen-containing gas are ejected from a burner and burned, quartz glass is deposited on a target, and this is made transparent to form a quartz glass ingot. The present invention provides a method for producing synthetic quartz glass, which comprises using a mixture of an organosilicon compound and a halogen compound of silicon as the silicon compound.

Next, the present invention has focused on the fact that the introduction of hydrogen molecules at the time of synthesis eliminates the need for secondary treatment for introducing hydrogen molecules, and has conducted intensive studies. as a result,
By specifying the flow rate of hydrogen gas ejected from the outermost ring-shaped tube, it has been found that the concentration of hydrogen molecules and OH groups that can impart UV resistance can be contained in quartz glass. .

[0016] The burner used in the manufacturing method of the present invention comprises:
A first tube arranged at a central portion for ejecting a raw material, a second tube arranged concentrically around the first tube and ejecting oxygen gas (hydrogen gas); A third tube disposed concentrically around the second tube and ejecting hydrogen gas (oxygen gas); and a third tube disposed concentrically around the third tube and ejecting hydrogen gas. A fourth pipe, a plurality of fifth pipes disposed between the outer circumference of the third pipe and the inner circumference of the fourth pipe, and for ejecting oxygen gas; and the fourth pipe A sixth pipe for ejecting hydrogen gas concentrically around the pipe, and being disposed between the outer circumference of the fourth pipe and the inner circumference of the sixth pipe and ejecting oxygen gas. And a plurality of seventh tubes for the burner.

Preferably, "the flow rate of hydrogen gas ejected from the sixth pipe is 4 to 7 m / s" and "the flow rate of hydrogen gas ejected from the seventh pipe is smaller than the flow rate of hydrogen gas ejected from the sixth pipe." The gas flow rate is high "and" The ratio of the oxygen gas ejected from the second tube to the hydrogen gas ejected from the third tube, and the oxygen gas ejected from the fifth tube and the fourth tube The ratio of the hydrogen gas ejected from the gas is larger than the stoichiometric combustion ratio. "

[0018]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, the halogen compound of silicon used as a raw material includes chlorine compounds (SiCl ₄ , SiHCl ₃ , SiH ₂ Cl ₂ , SiH ₃ C
l), fluorine compounds (SiF ₄ , Si ₂ F ₆ ) and the like. Chlorine has the effect of releasing metal impurities present in the synthesis atmosphere as halogen compounds to the outside of the system.However, in order to extremely deteriorate ultraviolet light resistance, when chlorine compounds are used as halogen compounds of silicon, chlorine Adjust so that the chlorine introduction amount (concentration) is 10 ppm or less.
Chlorine compounds as halogen compounds of silicon are SiCl ₄ , SiHC because they are liquid and easy to handle.
l ₃ is preferable, and it is also possible to introduce the compound into the burner as a chlorine compound such as Cl ₂ .

As the halogen compound of silicon, a fluorine compound is more preferable. By interposing fluorine having the same effect as chlorine in the synthesis atmosphere, the same effect as chlorine can be expected, and at the same time, UV resistance is improved by introducing a small amount of fluorine whose binding energy with silicon is larger than chlorine. The effect of increasing can also be provided. Further, by making the carbon present in the organosilicon molecule into a form of fluorocarbon instead of carbon dioxide, the generation rate of bubbles can be suppressed for an unknown reason. Although fluorine has many advantages as described above, it is difficult to control the fluorine concentration in the synthesis of quartz glass by the oxyhydrogen flame direct method, and if too much fluorine is introduced, a fluorine concentration distribution occurs, resulting in a large change in the refractive index. Therefore, the introduction amount is desirably about 100 ppm.

Na is dissolved in about 10 ppb to form an ultraviolet region, for example, an ArF excimer laser wavelength (193n).
In m), the transmittance is reduced by about 0.1%. When incorporated in an apparatus requiring a high transmittance, such as an excimer laser stepper, the imaging performance becomes extremely poor even if the transmittance is very small. Therefore, the fluctuation width of the Na concentration is preferably about 5 ppb or less.

As described above, in the method for producing quartz glass of the present invention, chlorine, Na,
Since it does not contain carbon, it is suitable for use as an optical element for ultraviolet lithography. Next, a method for introducing hydrogen molecules into quartz glass will be described. As described above, as a method for introducing hydrogen molecules, generally, a secondary treatment using a hot isostatic pressing (HIP), a high-temperature high-pressure atmosphere heat treatment furnace, or the like is often performed. During the secondary treatment, generation of oxygen-deficient defects or contamination of impurities such as Na when used as an ultraviolet optical material may cause problems, such as generation of an absorption band and devitrification depending on the treatment temperature range.

The method of introducing hydrogen during the synthesis of quartz glass as in the present invention does not have such disadvantages. Furthermore, in the secondary treatment, it is difficult to introduce hydrogen molecules into a large-diameter quartz glass member, whereas with the production method of the present invention, hydrogen molecules are introduced during synthesis,
A high concentration of hydrogen molecules can be maintained regardless of the diameter of the quartz glass.

FIG. 2 shows an apparatus for producing synthetic quartz glass used in the present invention. The burner 21 has a multi-tube structure made of quartz glass, and is installed from the upper part of the furnace to the target 22 with its tip end facing. The furnace wall is made of a refractory, and is provided with an observation window, an IR camera monitoring window 25, and an exhaust system 26. A target 22 for forming an ingot 27 is provided below the furnace, and the target 22 is connected to an XY stage 28 outside the furnace via a support shaft. The support shaft is rotatable by a motor.
Is movable two-dimensionally in the X direction and the Y direction in FIG. 1 by an X axis servo motor 23 and a Y axis servo motor 24. The drive of the X-axis servomotor 23 and the Y-axis servomotor 24 is controlled by a computer 30.

An oxygen-containing gas and a hydrogen-containing gas are jetted from the burner and mixed to form a flame. When the silicon compound as a raw material is diluted with a carrier gas and spouted from the center of the burner during this flame, the raw material is hydrolyzed to generate fine silica glass particles (soot). This is deposited on a rotating and oscillating target and melted and vitrified to obtain a transparent quartz glass ingot. At this time, the upper part of the ingot is covered with the flame, and the target is pulled down in the Z direction so that the position of the combined surface of the upper part of the ingot is always kept at the same distance from the burner.

The burner used in the present invention is disposed at the center and is provided with a first pipe for ejecting a raw material, and is arranged concentrically around the first pipe and ejects oxygen gas (hydrogen). A second tube, a third tube disposed concentrically around the second tube and for ejecting hydrogen gas (oxygen gas), and a concentric circle around the third tube. A fourth pipe arranged for ejecting hydrogen gas, and a plurality of fifth pipes arranged between the outer periphery of the third tube and the inner periphery of the fourth tube for ejecting oxygen gas. A pipe, a sixth pipe arranged concentrically around the fourth pipe and ejecting hydrogen gas, and a pipe between an outer circumference of the fourth pipe and an inner circumference of the sixth pipe. And a plurality of seventh tubes for ejecting oxygen gas. This burner is made of quartz glass, and it is possible to independently control the flow rate and flow rate of the gas ejected from each tube. Such control is
For example, this is performed using a mass flow controller.

An organosilicon compound and a halogen compound are introduced into the first tube. When the organosilicon compound itself is a liquid, it is sent to a vaporizer via a mass flow controller to evaporate the raw material, and then sent to a burner together with a carrier gas. A gaseous halogen compound such as silicon tetrafluoride is sent to a mass flow controller together with a carrier gas after baking. Each compound is mixed and a first is placed in the center of the burner.
Is introduced into the tube. As the carrier gas, a combustion gas such as oxygen or hydrogen, or an inert gas such as nitrogen or helium is used.

The combustion gas is introduced into each of the second to seventh pipes. The combustion gas is oxygen gas and hydrogen gas, which means gas containing oxygen and hydrogen, respectively. The process of dissolving hydrogen molecules in quartz glass during synthesis is not clear, but when the silicon compound gas ejected along with the carrier gas is hydrolyzed into fine particles, vitrification occurs while entraining a certain percentage of hydrogen molecules. It is supposed to be. Therefore, if the portion near the center is excessive in hydrogen, the probability that hydrogen molecules dissolve into quartz glass increases, and the hydrogen molecule concentration increases. Also, by making the flow rate of oxygen gas ejected from the outermost ring-shaped pipe larger than the flow rate of hydrogen gas, the reaction between the two can be completed at a portion farther from the burner, so that the concentration of OH group dissolved in the member In this way, in the method for producing quartz glass of the present invention, it is not necessary to perform secondary processing after synthesis that adversely affects optical performance. These quartz glasses are suitable for use as optical members for ultraviolet lithography.

In some cases, however, it is necessary to perform a heat treatment for adjusting the homogeneity and removing the distortion. At this time, the hydrogen molecules contained in the quartz glass member are released due to the diffusion phenomenon during the heat treatment, and the concentration decreases.
Some reduction in UV resistance occurs. However, with quartz glass synthesized by introducing sufficient hydrogen molecules by the production method of the present invention, an optical member having sufficient ultraviolet light resistance can be obtained even if the hydrogen molecule concentration is slightly reduced by the heat treatment. At this time, the hydrogen molecule concentration after the heat treatment was 2 × 1
It is desirable to set the number to 0 ¹⁷ to 4 × 10 ¹⁸ / cm ³ .

Examples of the present invention will be described below. Among them, the fluorine concentration and the carbon concentration were measured by ion chromatography by a combustion method, and the Na concentration was measured by activation analysis. [Organic silicon + halogen compound] Examples 1-1 to 1-6, 2-1 to 2-4, 3-1 to 3-
3, 4-1 A high-purity quartz glass ingot is prepared by burning oxygen gas and hydrogen gas at a flow rate shown in Table 1 with a quartz glass burner having a quintuple tube structure, and diluting the raw material with a carrier gas from the center. The synthesis was carried out by a method called a so-called oxyhydrogen flame hydrolysis method (FIG. 2). At the time of synthesis, a target composed of an opaque quartz glass plate on which glass is deposited is rotated (R) and rocked (X, Y) at a constant period,
Further, by simultaneously performing the descent (Z), the position of the upper part of the ingot was always kept constant from the burner.

[0030]

[Table 1]

Thus, a plurality of ingots were synthesized. From this ingot, cut out a test piece,
A measurement sample was obtained by polishing. Table 2 shows the results of this measurement.

[0032]

[Table 2]

Thus, Examples 1-1 to 1-6, 2-
In Examples 1 to 2-4 in which silicon tetrafluoride is used as the silicon halogen compound, quartz glass having excellent ultraviolet resistance can be obtained by containing fluorine in the quartz glass. In particular, in Examples 1-1 to 1-4, the Na concentration in the member was 10 ppb or less and the fluorine concentration was 100 ppb.
By setting m or less, a synthetic quartz glass having high ultraviolet transmittance and ultraviolet resistance can be obtained.

In Examples 3-1 to 3-3 and 4-1 also, quartz glass containing chlorine is contained in quartz glass by using SiCl ₄ and Cl ₂ as a halogen compound, and the quartz glass is excellent in ultraviolet resistance. Can be obtained. [Introduction of hydrogen molecule] Examples 5-1 to 5-5, 6-1 to 6-4, 7-1 to 7-
2 An example of synthesizing the quartz glass of the present invention using the burner shown in FIG. 1 is shown below. The OH group concentration was determined by infrared absorption at 2.7 μm, and the hydrogen molecule concentration was determined by Khotimche.
It was measured by Raman spectrophotometer according to the literature of mko et al.

The high-purity quartz glass ingot was prepared from high-purity silicon tetrachloride (Examples 5-1 to 5-5, 6-
1-6-4) or a mixture of organosilicon and a halogen compound of silicon (Examples 7-1 and 7-2), and FIG.
So-called oxyhydrogen flame hydrolysis, in which oxygen gas and hydrogen gas are burned at the flow rates shown in Table 3 with a quartz glass multi-tube burner as shown in FIG. The synthesis was performed by a method called the method (FIG. 2). Here, in Examples 5-1 to 5-5 and 6-1 to 6-4, oxygen gas was supplied from the second pipe, hydrogen gas was supplied from the third pipe, and in Examples 7-1 and 7-2, the second gas was supplied. Hydrogen gas was ejected from the tube and oxygen gas was ejected from the third tube.
During synthesis, a target made of an opaque quartz glass plate on which glass is laminated is rotated (R) and rocked (X,
Y), and by simultaneously performing the descent (Z), the position of the upper part of the ingot was always kept constant from the burner.

[0036]

[Table 3]

Thus, a plurality of ingots were synthesized. From this ingot, cut out a test piece,
A measurement sample was obtained by polishing. Table 2 shows an example of the result of this measurement.

[0038]

[Table 4]

As described above, by using a burner as shown in FIG. 1, hydrogen molecules can be contained in quartz glass at the time of synthesis, so that quartz glass excellent in ultraviolet transmittance and ultraviolet resistance can be obtained. it can. In particular, as in Examples 5-1 to 5-4 and 7-1, the flow rate of the hydrogen gas ejected from the sixth tube is set to 4 m / s or more and 7 m / s or less, and the hydrogen gas ejected from the sixth tube is used. By making the flow rate of the oxygen gas ejected from the seventh tube larger than the flow rate of the gas, it is possible to obtain quartz glass having particularly excellent ultraviolet transmittance and ultraviolet resistance.

[Brief description of the drawings]

FIG. 1 is a sectional view of a burner used in the present invention.

FIG. 2 shows a synthetic quartz glass manufacturing apparatus used in the present invention.

FIG. 3 is a correlation between the flow rate of the sixth pipe and the OH group concentration obtained when the flow rate of the sixth pipe is changed according to the present invention.

FIG. 4 is a correlation between the OH group concentration and the hydrogen molecule concentration of the synthetic quartz glass obtained according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st tube 2 2nd tube 3 3rd tube 4 4th tube 5 5th tube 6 6th tube 7 7th tube 21 Burner 22 Target 23 X-axis servomotor 24 Y-axis servomotor 25 Observation window 26 Exhaust system 27 Quartz glass ingot 28 XY stage 29 IR camera 30 Control system (computer)

Claims (19)

[Claims] 1. Production of synthetic quartz glass in which a silicon compound, an oxygen-containing gas, and a hydrogen-containing gas are ejected from a burner and burned, quartz glass is deposited on a target, and this is made transparent to form a quartz glass ingot. A method for producing synthetic quartz glass, wherein a mixture of an organic silicon compound and a halogen compound of silicon is used as the silicon compound. 2. The method for producing synthetic quartz glass according to claim 1, wherein said silicon compound is a mixture of an organosilicon compound and a fluorine compound of silicon. 3. The method for producing synthetic quartz glass according to claim 1, wherein said silicon compound is a mixture of an organosilicon compound and a halogen compound. 4. The method for producing a synthetic quartz glass optical member according to claim 1, wherein said organosilicon compound is alkoxysilane. 5. The method for producing a synthetic quartz glass optical member according to claim 1, wherein said organosilicon compound is siloxane. 6. The method for producing a synthetic quartz glass optical member according to claim 2, wherein said fluorine compound of silicon is silicon tetrafluoride. 7. The method for producing a synthetic quartz glass optical member according to claim 2, wherein the mole fraction of the silicon fluorine compound contained in the mixture of the organosilicon compound and the silicon fluorine compound is 5 to 15%. A method for producing synthetic quartz glass, comprising: 8. The method for producing synthetic quartz glass according to claim 1, wherein said burner is arranged at a central portion and a first pipe for ejecting a raw material, and a concentric circle is provided around said first pipe. A second tube for ejecting oxygen gas, and a third tube concentrically arranged around the second tube for ejecting hydrogen gas, and the third tube And a fourth pipe for ejecting hydrogen gas concentrically around the pipe, and disposed between the outer circumference of the third pipe and the inner circumference of the fourth pipe and ejecting oxygen gas. A plurality of fifth tubes, a sixth tube arranged concentrically around the fourth tube and for ejecting hydrogen gas, an outer periphery of the fourth tube and the sixth tube And a plurality of seventh tubes for ejecting oxygen gas disposed between the burner and the inner periphery of the burner. Method for producing a quartz glass. 9. The method for producing synthetic quartz glass according to claim 8, wherein the flow rate of the hydrogen gas ejected from the sixth tube is 4 m / s or more and 7 m / s or less, and the hydrogen gas ejected from the sixth tube is used. A method for producing synthetic quartz glass, characterized in that the production is carried out by increasing the flow rate of oxygen gas ejected from the seventh tube as compared to the gas flow rate. 10. The method for producing synthetic quartz glass according to claim 8, wherein a ratio of oxygen gas ejected from the second tube to hydrogen gas ejected from the third tube and the ratio of oxygen gas ejected from the third tube are ejected from the fifth tube. Wherein the ratio of oxygen gas to hydrogen gas ejected from the fourth tube is larger than hydrogen in the theoretical combustion ratio. 11. The method for producing synthetic quartz glass according to claim 1, wherein said burner is arranged at a central portion and a first tube for ejecting a raw material, and a concentric circle is provided around said first tube. A second tube for discharging hydrogen gas, a third tube concentrically disposed around the second tube for discharging oxygen gas, and the third tube A fourth pipe for ejecting hydrogen gas concentrically around the pipe, and being disposed between the outer circumference of the third pipe and the inner circumference of the fourth pipe and ejecting oxygen gas. A plurality of fifth tubes, a sixth tube arranged concentrically around the fourth tube and for ejecting hydrogen gas, an outer periphery of the fourth tube and the sixth tube A plurality of seventh pipes disposed between the inner circumference and a plurality of seventh tubes for ejecting oxygen gas. Method for producing a quartz glass. 12. The method for producing synthetic quartz glass according to claim 11, wherein the flow rate of the hydrogen gas ejected from the sixth tube is set to 4 m / s or more and 7 m / s or less, and the hydrogen gas ejected from the sixth tube is used. A method for producing synthetic quartz glass, characterized in that the production is carried out by increasing the flow rate of oxygen gas ejected from the seventh tube as compared to the gas flow rate. 13. The method for producing synthetic quartz glass according to claim 11, wherein the ratio of oxygen gas ejected from the fifth tube to hydrogen gas ejected from the fourth tube and the ratio of oxygen gas ejected from the fourth tube are increased. Wherein the ratio of oxygen gas to hydrogen gas ejected from the sixth tube is greater than the theoretical combustion ratio for hydrogen. 14. A synthetic quartz glass optical member manufactured by the manufacturing method according to claim 1, wherein the Na concentration in the optical member is 10 ppb or less and the fluctuation width of the concentration in the radial direction is 5 ppb or less. A synthetic quartz glass optical member characterized by the above-mentioned. 15. A synthetic quartz glass optical member manufactured by the manufacturing method according to claim 1, wherein the concentration of carbon contained in the optical member is 10 ppm or less. 16. A synthetic quartz glass optical member according to claim 2, wherein the concentration of fluorine contained in said optical member is 100 ppm or less. 17. The synthetic quartz glass optical member obtained by the method according to claim 8 or 11, wherein the hydrogen molecule concentration in the member is 1 × 10 ^{18 to} 5 × 10 ¹⁸ / c.
A synthetic quartz glass optical member for ultraviolet light, characterized in that m ³ has an OH group concentration of 900 to 1100 ppm. 18. A synthetic quartz glass optical member obtained by the method according to claim 8 or 11, wherein
A synthetic quartz glass optical member for ultraviolet light, wherein the concentration of hydrogen molecules in the member after heat treatment for 0 hour is 2 × 10 ¹⁷ to 4 × 10 ¹⁸ / cm ³ . 19. The synthetic quartz glass optical member according to claim 18, wherein the heat treatment temperature in the atmosphere is 800-1.
A synthetic quartz glass optical member for ultraviolet light, wherein the temperature is 100 ° C.