JPWO2005101456A1 - Synthetic quartz glass tube for excimer UV lamp and manufacturing method thereof - Google Patents

Abstract

The synthetic quartz glass tube for excimer UV lamp of the present invention is made of high-purity synthetic quartz glass, and is a synthetic quartz glass tube for excimer UV lamp that emits vacuum ultraviolet light having a wavelength of 150 to 250 nm. Has a length of 1000 mm or more, an outer diameter of 10 mm or more and 50 mm or less, a wall thickness of 0.8 mm or more and 2.8 mm or less, and no scratches on the surface having a width of 0.5 mm or more or a length of 150 mm or more. The difference is 1.4 mm or less, preferably 0.7 mm or less, the difference between the maximum value and the minimum value of the wall thickness is 0.5 mm or less, preferably 0.3 mm or less, and the bending per 1000 mm in length is 1.5 mm or less, preferably 0.00. It is 7 mm or less. If the synthetic quartz glass tube for excimer UV lamps of the present invention is used, an excimer UV lamp capable of emitting light uniformly with high performance can be obtained.

Description

  The present invention relates to a synthetic quartz glass tube constituting a light transmissive portion of an excimer UV lamp that emits vacuum ultraviolet light having a wavelength of 150 to 250 nm.

Along with the increase in size of the LCD substrate, the size of the substrate cleaning apparatus has also increased, and the length of the excimer UV lamp mounted thereon has also been increased. The synthetic quartz glass tube constituting the excimer UV lamp is required to have high dimensional accuracy in terms of discharge characteristics and light emission efficiency. However, in such a long quartz glass tube, the discharge characteristics and light emission over the entire length of the long lamp are required. Due to the need for uniform efficiency, the demands on dimensional accuracy are becoming more stringent.
Japanese Patent Application Laid-Open No. 7-215731 discloses a high-purity silica glass for ultraviolet lamps and a method for producing the same, but a long and high dimensional accuracy quartz glass tube is required as required for today's excimer UV lamps. The conditions necessary for this are not clear, and only a synthetic quartz glass tube having a diameter of 30 mm, a thickness of 2 mm, and a length of 200 mm has been produced.

Accordingly, an object of the present invention is to provide a long and high dimensional accuracy quartz glass tube as required for today's excimer UV lamps, and a method for manufacturing the same.
In addition, the inventors of the present invention have intensively studied impurities in the quartz glass tube in order to improve the UV lamp. As a result, they discovered V as an impurity, and when the concentration of V exceeds a predetermined value. The present inventors have found that it is not preferable because it absorbs ultraviolet rays and shifts the ultraviolet absorption edge to the longer wavelength side to cause a decrease in transmittance.
Another object of the present invention is to provide a synthetic quartz glass tube for an excimer UV lamp apparatus in which the impurity concentration is suppressed as much as possible in order to improve the performance of the excimer UV lamp apparatus.
The above purpose is as follows. ~ 8. This is achieved by any one of the configurations.
1. In a synthetic quartz glass tube for excimer UV lamps, which is made of high purity synthetic quartz glass and emits vacuum ultraviolet light with a wavelength of 150 to 250 nm, the synthetic quartz glass tube has a length of 1000 mm or more, an outer diameter of 10 mm or more and 50 mm or less, The thickness is 0.8 mm or more and 2.8 mm or less, the surface has no scratch of width 0.5 mm or more or length 150 mm or more, and the difference between the maximum value and the minimum value of the outer diameter is 1.4 mm or less, preferably 0.7 mm or less, For excimer UV lamps, characterized in that the difference between the maximum value and the minimum value of the wall thickness is 0.5 mm or less, preferably 0.3 mm or less, and the bending per 1000 mm in length is 1.5 mm or less, preferably 0.7 mm or less. Synthetic quartz glass tube.
2. Each element concentration of Li, Na, K, Ca, Mg, Ti, Fe, Ni, Cu, Cr, Mo, W, V is less than 5 wtppb, preferably each concentration of all the above elements is less than 3 wtppb, more preferably Each of the above-mentioned concentrations of all the elements is less than 1 wtppb. A synthetic quartz glass tube for the excimer UV lamp described.
3. 1. The spectral transmittance at a wavelength of 172 nm from the inner surface to the outer surface of a synthetic quartz glass tube having a wall thickness of 0.8 mm or more and 2.8 mm or less is 80% or more, preferably 83% or more. Or 2. A synthetic quartz glass tube for the excimer UV lamp described.
4). 1. The above-mentioned 1. characterized in that the OH group concentration in the synthetic quartz glass tube is 10 wtppm or more and 400 wtppm or less, and the Cl element concentration is 30 wtppm or less, preferably 5 wtppm or less. ~ 3. A synthetic quartz glass tube for excimer UV lamps according to any one of the above.
5. For excimer UV lamps that emit vacuum ultraviolet light with a wavelength of 150 to 250 nm, the dimensions are 1000 mm or more in length, the outer diameter is 10 mm or more and 50 mm or less, the wall thickness is 0.8 mm or more and 2.8 mm or less, and the width is 0.5 mm on the surface. There is no scratch with a length of 150 mm or more, the difference between the maximum value and the minimum value of the outer diameter is 1.4 mm or less, preferably 0.7 mm or less, and the difference between the maximum value and the minimum value of the wall thickness is 0.5 mm or less, preferably A method for producing a synthetic quartz glass tube for excimer UV lamps for producing a synthetic quartz glass tube for excimer UV lamps having a bend of not more than 0.3 mm and a length per 1000 mm of 1.5 mm or less, preferably 0.7 mm or less, A quartz glass cylinder having a wall thickness variation rate of 1.8% or less and a surface roughness of 18 μm or less is determined by a non-contact heating drawing method using a cylindrical electric heating furnace. Synthetic quartz for excimer UV lamps by pulling while maintaining the internal pressure and pulling speed in the tube so that the variation from the set value is within ± 5% so that the diameter and the wall thickness can be obtained. A method for producing a synthetic quartz glass tube for excimer UV lamps, characterized by producing a glass tube.
6). The concentration of each element of Li, Na, K, Ca, Mg, Ti, Fe, Ni, Cu, Cr, Mo, W, and V is less than 5 wtppb, and preferably the concentration of all the above elements is less than 3 wtppb. More preferably, the respective concentrations of all the above elements are less than 1 wtppb. A method for producing a synthetic quartz glass tube for an excimer UV lamp as described.
7). 4. Spectral transmittance at a wavelength of 172 nm from the inner surface to the outer surface of the synthetic quartz glass tube is 80% or more, preferably 83% or more. Or 6. A method for producing a synthetic quartz glass tube for an excimer UV lamp as described.
8). 4. The above-mentioned 5. characterized in that the OH group concentration in the synthetic quartz glass tube is 10 wtppm or more and 400 wtppm or less, and the Cl element concentration is 30 wtppm or less, preferably 5 wtppm or less. ~ 7. A method for producing a synthetic quartz glass tube for an excimer UV lamp according to any one of the above.
In Japanese Patent Laid-Open No. 07-109136, a quartz glass tube and a method for manufacturing the same are disclosed. The quartz glass tube is used for drawing an optical fiber and has an outer diameter of 50 to 300 mmφ and a thickness. It is a large size of 10 mm or more, and the technical field is completely different from the synthetic quartz glass tube for excimer UV lamp apparatus of the present invention.

FIG. 1 is a diagram for explaining an outline of an excimer UV lamp obtained by an embodiment of the present invention and a performance test of a synthetic quartz glass tube used therefor.
FIG. 2 is a diagram for explaining a method of manufacturing a synthetic quartz glass tube for an excimer UV lamp according to an embodiment of the present invention.

A synthetic quartz glass tube for excimer UV lamps according to an embodiment of the present invention is for excimer UV lamps that emit vacuum ultraviolet light having a wavelength of 150 to 250 nm, and is made of high-purity synthetic quartz glass. The glass tube has a length of 1000 mm or more, an outer diameter of 10 mm or more and 50 mm or less, and a wall thickness of 0.8 mm or more and 2.8 mm or less.
This is because when the size of the synthetic quartz glass tube is less than the above, it is impossible to cope with an increase in the size of the cleaning device. Currently, the upper limit of the length is about 5000 mm.
If the wall thickness is less than the above, the strength as a lamp tube may be insufficient, and if it exceeds that, sufficient light transmission cannot be obtained.
Synthetic quartz glass tubes for excimer UV lamps have no scratches with a width of 0.5 mm or more or a length of 150 mm or more on the surface, and the difference between the maximum and minimum outer diameters is 1.4 mm or less, preferably 0.7 mm or less. A synthetic quartz glass tube in which the difference between the maximum value and the minimum value of the wall thickness is 0.5 mm or less, preferably 0.3 mm or less, and the bending per 1000 mm in length is 1.5 mm or less, preferably 0.7 mm or less is suitable. . If there is a scratch having a width of 0.5 mm or more or a length of 150 mm or more, the excimer UV light may be scattered or the lamp itself may be damaged. Further, if the difference between the maximum value and the minimum value of the outer diameter is larger than 1.4 mm, the distance between the internal electrodes varies when the excimer UV lamp is configured, so that the discharge is not performed uniformly. If it is smaller than 0.001 mm, the yield decreases, which is undesirable from the viewpoint of cost. Similarly, an excimer having a double-pipe structure in which the difference between the maximum value and the minimum value of the wall thickness is larger than 0.5 mm or the bending per 1000 mm in length exceeds 1.5 mm. When a UV lamp is constructed, there is a risk of deterioration of discharge characteristics between electrodes attached to the outer side of the outer tube and the inner side of the inner tube. In either case, if it is smaller than 0.001 mm, the yield decreases, which is not preferable from the viewpoint of cost.
Further, the synthetic quartz glass tube has a concentration of each element of Li, Na, K, Ca, Mg, Ti, Cr, Fe, Ni, Cu, Mo, W, and V of less than 5 wtppb, preferably each of the above elements. Is preferably less than 3 wtppb, more preferably each concentration of all the above elements is less than 1 wtppb. Alkali metal elements and alkaline earth metal elements such as Li, Na, K, and Ca are contained in factory building materials, etc., but if they are above the above range, recrystallization of quartz glass is promoted and cristobalite is easily generated. White devitrification occurs. In addition, transition metal elements such as Ti, Cr, Fe, Ni, Cu, Mo, and W are often contained in heat-resistant alloys used in an apparatus for producing synthetic quartz glass, but when their concentration exceeds the above range. This is not preferable because it absorbs ultraviolet rays and shifts the ultraviolet absorption edge to the longer wavelength side, leading to a decrease in transmittance. V is also unfavorable if it exceeds a predetermined concentration because it absorbs ultraviolet rays and shifts the ultraviolet absorption edge to the longer wavelength side, leading to a decrease in transmittance. However, in order to make the concentration of any element less than 0.01 wtppb, a clean manufacturing environment equivalent to a clean room is required in all the manufacturing steps, which is not desirable because the cost increases. Note that the impurity V was first discovered by the inventors of the present invention in the present invention.
Further, the synthetic quartz glass tube having a wall thickness of 0.8 mm or more and 2.8 mm or less has a spectral transmittance at an initial wavelength of 172 nm from the inner surface to the outer surface of 80% or more, preferably 83% or more, and an OH group concentration of 10 wtppm or more and 400 wtppm. In the following, it is preferable that 190 wtppm or more and 320 wtppm or less, and the Cl element concentration be 30 wtppm or less, preferably 5 wtppm or less. If the spectral transmittance from the inner surface to the outer surface at a wavelength of 172 nm is less than 80%, when an excimer UV lamp is constructed, the cleaning effect on the object to be cleaned is reduced due to insufficient ultraviolet light quantity.
In addition, the OH group becomes the end of the structure in the quartz glass network structure. If an appropriate amount of this OH group is contained in the quartz glass, the internal strain in the network structure is relaxed, and the Si—O—Si bond angle is stable. It is said that the average bond energy of Si—O increases as the value approaches. However, when OH groups are contained in a high concentration, the transmittance in the ultraviolet region is lowered. Therefore, in the synthetic quartz glass tube of the present invention, the OH group concentration is set in the range of 10 wtppm to 400 wtppm.
Si-Cl formed by Cl element becomes an absorption band of 210 to 220 nm, that is, a so-called E 'center precursor. However, if the Cl element concentration is 30 wtppm or less, preferably 5 wtppm or less, a decrease in transmittance is not a problem. It need not be less than 0.01 wtppm.
In order to manufacture the long synthetic quartz glass tube for the excimer UV lamp of the present invention according to the embodiment of the present invention, cylindrical quartz which is an original tube obtained by cutting and polishing a cylindrical quartz glass ingot The fluctuation range of the thickness of the glass cylinder is set to 1.8% or less, the surface roughness is set to about 18 μm or less, and the inner pressure and the drawing speed of the pipe are adjusted so as to obtain a predetermined diameter and thickness by a non-contact heating drawing method. Manufacture while keeping it correct and constant. If the fluctuation range of the thickness of the cylindrical quartz glass cylinder, which is the original tube, is not less than 1.8%, the difference between the maximum and minimum outside diameters and the maximum thickness when the synthetic quartz glass tube is manufactured If the difference between the minimum value and the bending does not fall within the scope of the present invention and the surface roughness is 18 μm or less, the surface is 0.5 mm or more in width or 150 mm or more in length even if the tube is drawn by the non-contact heating drawing method. There is a risk of scratches remaining.
In addition, the fluctuation rate of the thickness of the cylindrical quartz glass cylinder which is the original tube is defined by the following equation.
Fluctuation rate (%) = (maximum thickness−minimum thickness) / {(maximum thickness + minimum thickness) / 2} × 100
That is, a cylindrical quartz glass ingot made by a gas phase shaft attaching method (VAD method) or an external attaching method (OVD method) or the like is accurately ground to a predetermined dimension by a cylindrical grinding apparatus equipped with diamond abrasive grains, Polishing with a cerium oxide polishing machine, aligning the dimensions with a non-contact laser type measuring machine, accurately determining the center of the outer diameter, opening it with an ultra-precision honing device in accordance with the center of the outer diameter, and using hydrofluoric acid When an etching process, washing with pure water, and drying are performed, a cylindrical quartz glass cylinder in which the centers of the outer circumference circle and the inner circumference circle coincide with each other can be obtained.
Next, by a non-contact heating and stretching method using a cylindrical electric heating furnace, predetermined tube pressure and tube drawing speed determined from the dimensions and thickness of the cylindrical quartz glass cylinder, the glass viscosity at the time of heating, the stretching ratio, etc. Heat processing is performed while accurately maintaining ± 5% of the set value. At this time, the internal pressure of the pipe is set in a range of 2 atm to 1/10 atm, and the pulling speed is set in a range of 1 m / min to 60 m / min. Also, since the high-temperature heat treatment at this time eliminates the roughness and scratches of the grinding surface during mechanical grinding, manufactures a long quartz glass tube with a smooth surface with high dimensional accuracy suitable for excimer UV lamp applications. can do.
To maintain the pipe pressure and pipe drawing speed accurately within ± 5% of the set values, the pipe pressure is controlled using a precision pressure controller, and the pipe drawing speed is controlled using a high-precision rotary motor. Can be done.
[Measurement of dimensions]
The outer diameter is measured with a non-contact laser type measuring device at intervals of 50 mm for a quartz glass tube having a predetermined length, and the difference between the maximum value and the minimum value of the outer diameter on the circumference is obtained. The wall thickness is measured with a non-contact laser type measuring device at intervals of 50 mm with respect to a quartz glass tube having a predetermined length, and the difference between the maximum value and the minimum value of the wall thickness on the circumference is obtained. In addition, bending refers to rotating a quartz glass tube of a predetermined length around 50 mm from both ends of the tube as a fulcrum, and obtaining the maximum and minimum displacements at the center of the tube using a non-contact laser measuring instrument. The difference is set to a half. The bending per 1000 mm in length is a value obtained by proportionally converting the value of bending between fulcrums to the value per 1000 mm of the synthetic quartz glass tube.
[Scratches on the surface]
Visual observation is performed under scattered light, and this size is measured when scratches are found.
[Impurity element analysis]
By ICP emission spectroscopy.
[Transmittance measurement]
Measuring method using vacuum ultraviolet spectrophotometer.
[OH group concentration]
D. M.M. DODD and D.D. B. FRASER, Optical determination of OH in fused silica, Journal of Applied Physics, Vol. 37 (1966) p. Measurement method using infrared spectrophotometer described in 3911 document.
[Cl element concentration]
Measurement method by turbidimetric method with AgNO ₃ addition after decomposition with HF aqueous solution.

(1) A large porous soot body produced by an external method (OVD method) in which silicon tetrachloride vaporized on a rotating target is flame-hydrolyzed in oxyhydrogen to deposit silica soot is transparent at 1600 ° C. in a vacuum atmosphere. Vitrified to produce a cylindrical quartz glass ingot. Both ends of this cylindrical quartz glass ingot are cut, and the outer periphery thereof is accurately ground to a predetermined size with a cylindrical grinding machine equipped with diamond abrasive grains, then polished with a cerium oxide polishing machine and dimensioned with a non-contact laser type measuring machine. The circle center of the outer diameter was obtained. A quartz glass cylinder having a length of 3000 mm, an outer diameter of 200 mm, and an inner diameter of 50 mm is obtained by opening with an ultra-precision honing device in accordance with the circle center of the outer diameter, and performing etching treatment with hydrofluoric acid, washing with pure water, and drying. It was. The variation rate of the thickness of the quartz glass cylinder was 1.6%, and the surface roughness was 17 μm.
The quartz glass cylinder is set in a vertical resistance heating furnace having a carbon cylindrical heating element as shown in FIG. 2, the temperature of the cylindrical heater is set to 2200 ° C., and the lower end of the tube is sealed with a dummy tube. The synthetic quartz glass tube with an outer diameter of 35 mm and a wall thickness of 1 mm at a constant tube drawing speed by a drawing roll while nitrogen gas is introduced into the tube from the upper end and the nitrogen gas pressure in the tube is accurately maintained by a pressure controller. Stretched. The fluctuations from the set values of the internal pressure and the drawing speed in the pipe during the drawing were ± 3% and ± 2%, respectively.
The obtained synthetic quartz glass tube was cut to a length of 1500 mm, and the outer diameter, thickness, and displacement from the rotating shaft were measured with a non-contact laser measuring instrument. The difference between the maximum value and the minimum value of the thickness was 0.3 mm, and the bending was 0.6 mm. That is, the bending per 1000 mm in length was 0.43 mm. Further, no scratch with a width of 0.5 mm or more or a length of 150 mm or more was observed on the surface.
Table 1 shows the impurity element concentration, the transmittance at a wavelength of 172 nm, the OH group concentration, and the Cl element concentration of the obtained synthetic quartz glass tube.
(2) A synthetic quartz glass tube having an outer diameter of 12 mm and a wall thickness of 1 mm was produced in the same manner as in (1). The obtained synthetic quartz glass tube was cut to a length of 1500 mm, and the outer diameter, thickness, and displacement from the rotating shaft were measured with a non-contact laser measuring instrument. 0.4 mm, the difference between the maximum value and the minimum value of the wall thickness was 0.1 mm, and the bending was 0.6 mm. That is, the bending per 1000 mm in length was 0.43 mm. Further, no scratch with a width of 0.5 mm or more or a length of 150 mm or more was observed on the surface.
Table 1 shows the impurity element concentration, the transmittance at a wavelength of 172 nm, the OH group concentration, and the Cl element concentration of the synthetic quartz glass tube.
(3) The excimer having a total length of 1400 mm shown in FIG. 1 is formed by forming an electrode section using the obtained synthetic silica glass tube of (1) as an outer tube and the synthetic silica glass tube of (2) as an inner tube and enclosing xenon gas. A UV lamp was produced. The lamp was connected to the high-frequency power supply device shown in FIG. 1, applied with a predetermined voltage, turned on, and the intensity of radiated light having a wavelength of 172 nm on the lamp surface after 100 hours was measured. The measurement was performed at a position of A) 80 mm, B) lamp center, and C) 1320 mm from one light emitting portion end to the other end portion. When the radiated light intensity at each position is expressed by relative intensity when the intensity at the position B) is 100, almost uniform intensity is obtained depending on the measurement position as shown in Table 2.

(1) Example 1 except that a porous soot body was prepared by a gas phase axial method (VAD method) in which silicon tetrachloride vaporized on a rotating target was flame-hydrolyzed in oxyhydrogen to deposit silica soot. A synthetic quartz glass tube having an outer diameter of 35 mm and a wall thickness of 1 mm was manufactured by the same method. Note that the variation rate of the thickness of the quartz glass cylinder during the production was 1.7%, and the surface roughness was 17 μm.
The obtained synthetic quartz glass tube was cut to a length of 1500 mm, and the outer diameter, thickness, and displacement from the rotating shaft were measured with a non-contact laser measuring instrument. The difference between the maximum value and the minimum value of the wall thickness was 0.7 mm, and the bending was 1.1 mm. That is, the bending per 1000 mm in length was 0.79 mm. Further, no scratch with a width of 0.5 mm or more or a length of 150 mm or more was observed on the surface.
Table 1 shows the impurity element concentration, the transmittance at a wavelength of 172 nm, the OH group concentration, and the Cl element concentration of the obtained synthetic quartz glass tube.
(2) A synthetic quartz glass tube having an outer diameter of 12 mm and a wall thickness of 1 mm was produced in the same manner as in (1). The obtained synthetic quartz glass tube was cut to a length of 1500 mm, and the outer diameter, thickness, and displacement from the rotating shaft were measured with a non-contact laser measuring instrument. The difference between the maximum value and the minimum value of 0.7 mm was 0.25 mm, and the bending was 1.1 mm. That is, the bending per 1000 mm in length was 0.79 mm. Further, no scratch with a width of 0.5 mm or more or a length of 150 mm or more was observed on the surface.
Table 1 shows the impurity element concentration, the transmittance at a wavelength of 172 nm, the OH group concentration, and the Cl element concentration of the synthetic quartz glass tube.
(3) The excimer having a total length of 1400 mm shown in FIG. 1 is formed by forming an electrode section using the obtained synthetic silica glass tube of (1) as an outer tube and the synthetic silica glass tube of (2) as an inner tube and enclosing xenon gas. A UV lamp was produced. The lamp was connected to the high-frequency power supply device shown in FIG. 1, applied with a predetermined voltage, turned on, and the intensity of radiated light having a wavelength of 172 nm on the lamp surface after 100 hours was measured. The measurement was performed at a position of A) 80 mm, B) lamp center, and C) 1320 mm from one light emitting portion end to the other end portion. When the radiated light intensity at each position is expressed as a relative intensity when the intensity at the position B) of Example 1 is 100, as shown in Table 2, it is almost the same and uniform depending on the measurement position as in Example 1. It became strength.
[Comparative Example 1]
{Circle around (1)} A synthetic quartz glass tube having an outer diameter of 35 mm and a wall thickness of 1 mm was produced in the same manner as in Example 1 except that a hole was opened with a honing device without aligning the circular center of the outer diameter of the cylindrical quartz glass ingot. During the production, the variation rate of the thickness of the quartz glass cylinder was 5.2%, and the surface roughness was 32 μm.
The obtained synthetic quartz glass tube was cut to a length of 1500 mm, and the outer diameter, thickness, and displacement from the rotating shaft were measured with a non-contact laser measuring instrument. 1.7 mm, the difference between the maximum value and the minimum value of the wall thickness was 0.4 mm, and the bending was 3.3 mm. That is, the bending per 1000 mm in length was 2.29 mm. Further, the impurity element concentration, the transmittance at a wavelength of 172 nm, the OH group concentration, and the Cl element concentration of the synthetic quartz glass tube were as shown in Table 1, respectively.
(2) A synthetic quartz glass tube having an outer diameter of 12 mm and a wall thickness of 1 mm was produced in the same manner as in (1). The obtained synthetic quartz glass tube was cut to a length of 1500 mm, and the outer diameter, thickness, and displacement from the rotating shaft were measured with a non-contact laser measuring instrument. The difference between the maximum value and the minimum value of the thickness was 1.85 mm, the bending was 3.2 mm. That is, the bending per 1000 mm in length was 2.29 mm. Further, the impurity element concentration, the transmittance at a wavelength of 172 nm, the OH group concentration, and the Cl element concentration of the synthetic quartz glass tube were as shown in Table 1, respectively.
(3) The obtained synthetic quartz glass tube of (1) is an outer tube, and the synthetic quartz glass tube of (2) is an inner tube to constitute an electrode portion and enclose xenon gas and have a total length of 1400 mm as shown in FIG. Excimer UV lamps were manufactured. The lamp was connected to the high-frequency power supply device shown in FIG. 1, applied with a predetermined voltage, turned on, and the intensity of radiated light having a wavelength of 172 nm on the lamp surface after 100 hours was measured. The measurement was performed at a position of A) 80 mm, B) lamp center, and C) 1320 mm from one light emitting portion end to the other end portion. When the intensity of the radiated light at each position is expressed by the relative intensity when the intensity at the position B) in Example 1 is set to 100, the value greatly changed depending on the measurement position as shown in Table 2.
[Comparative Example 2]
(1) An outer diameter of 35 mm and a wall thickness of 1 mm were obtained in the same manner as in Example 1 except that the tube was drawn without controlling the nitrogen gas pressure in the synthetic quartz glass cylinder and keeping the tube drawing speed constant. A synthetic quartz glass tube was manufactured. The fluctuations from the set values of the internal pressure and the drawing speed in the pipe during the drawing were ± 7% and ± 6%, respectively. The obtained synthetic quartz glass tube was cut to a length of 1500 mm, and the outer diameter, thickness, and displacement from the rotating shaft were measured with a non-contact laser measuring instrument. The difference between the maximum value and the minimum value of the wall thickness was 1.9 mm, the bend was 3.2 mm. That is, the bending per 1000 mm in length was 2.29 mm. Further, the impurity element concentration, the transmittance at a wavelength of 172 nm, the OH group concentration, and the Cl element concentration of the synthetic quartz glass tube were as shown in Table 1, respectively.
(2) A synthetic quartz glass tube having an outer diameter of 12 mm and a wall thickness of 1 mm was produced in the same manner as in (1). The obtained synthetic quartz glass tube was cut to a length of 1500 mm, and the outer diameter, thickness, and displacement from the rotating shaft were measured with a non-contact laser measuring instrument. The difference between the maximum value and the minimum value of the thickness was 1.8 mm, and the bending was 3.1 mm. That is, the bending per 1000 mm in length was 2.29 mm. Further, the impurity element concentration, the transmittance at a wavelength of 172 nm, the OH group concentration, and the Cl element concentration of the synthetic quartz glass tube were as shown in Table 1, respectively.
(3) The obtained synthetic quartz glass tube of (1) is an outer tube, and the synthetic quartz glass tube of (2) is an inner tube to constitute an electrode portion and enclose xenon gas and have a total length of 1400 mm as shown in FIG. Excimer UV lamps were manufactured. The lamp was connected to the high-frequency power supply device shown in FIG. 1, applied with a predetermined voltage, turned on, and the intensity of radiated light having a wavelength of 172 nm on the lamp surface after 100 hours was measured. The measurement was performed at a position of A) 80 mm, B) lamp center, and C) 1320 mm from one light emitting portion end to the other end portion. When the intensity of the radiated light at each position is expressed by the relative intensity when the intensity at the position B) in Example 1 is 100, the value varies greatly depending on the measurement position as shown in Table 2, and the intensity is not uniform. became.
[Comparative Example 3]
(1) When drawing a synthetic quartz glass cylinder, instead of using a non-contact heating drawing method, a contact heating method is used in which a graphite guide is brought into direct contact with the synthetic quartz glass cylinder in a vertical resistance heating furnace. A synthetic quartz glass tube having an outer diameter of 35 mm and a wall thickness of 1 mm was produced in the same manner as in Example 1 except that the tube was drawn.
The obtained synthetic quartz glass tube was cut to a length of 1500 mm, and the outer diameter, thickness, and displacement from the rotating shaft were measured with a non-contact laser measuring instrument. The difference between the maximum value and the minimum value of the thickness was 0.7 mm, the bending was 1.7 mm. That is, the bending per 1000 mm in length was 1.21 mm. Further, the impurity element concentration, the transmittance at a wavelength of 172 nm, the OH group concentration, and the Cl element concentration of the synthetic quartz glass tube were as shown in Table 1, respectively.
(2) A synthetic quartz glass tube having an outer diameter of 12 mm and a wall thickness of 1 mm was produced in the same manner as in (1). The obtained synthetic quartz glass tube was cut to a length of 1500 mm, and the outer diameter, thickness, and displacement from the rotating shaft were measured with a non-contact laser measuring instrument. The difference between the maximum value and the minimum value of the thickness was 0.55 mm, and the bending was 1.5 mm. That is, the bending per 1000 mm in length was 1.07 mm. Further, the impurity element concentration, the transmittance at a wavelength of 172 nm, the OH group concentration, and the Cl element concentration of the synthetic quartz glass tube were as shown in Table 1, respectively.
In this comparative example, the impurity concentration increased because when the synthetic quartz glass cylinder was drawn, the graphite guide was directly attached to the synthetic quartz glass cylinder in the vertical resistance heating furnace instead of using the non-contact heating drawing method. It is thought that it is the result of pipe drawing using the contact-type heat processing method to contact.
(3) The obtained synthetic quartz glass tube of (1) is an outer tube, and the synthetic quartz glass tube of (2) is an inner tube to constitute an electrode portion and enclose xenon gas and have a total length of 1400 mm as shown in FIG. Excimer UV lamps were manufactured. The lamp was connected to the high-frequency power supply device shown in FIG. 1, applied with a predetermined voltage, turned on, and the intensity of radiated light having a wavelength of 172 nm on the lamp surface after 100 hours was measured. The measurement was performed at a position of A) 80 mm, B) lamp center, and C) 1320 mm from one light emitting portion end to the other end portion. The radiated light intensity at each position is expressed as a relative intensity when the intensity at the position B) in Example 1 is set to 100. As shown in Table 2, the intensity is significantly lower than that in Example 1. became.
From the above, the effect of the present invention is clear.

Since the synthetic quartz glass tube of the present invention is long but has high dimensional accuracy, when an excimer UV lamp having a double tube structure is formed using this, the long glass tube having uniform light emission characteristics over the entire length of the lamp is used. Excimer UV lamps can be manufactured.

Claims (18)

In a synthetic quartz glass tube for excimer UV lamps, which is made of high purity synthetic quartz glass and emits vacuum ultraviolet light with a wavelength of 150 to 250 nm, the synthetic quartz glass tube has a length of 1000 mm or more, an outer diameter of 10 mm or more and 50 mm or less, The thickness is 0.8 mm or more and 2.8 mm or less, there is no scratch on the surface of width 0.5 mm or more or length 150 mm or more, the difference between the maximum value and the minimum value of the outer diameter is 1.4 mm or less, A synthetic quartz glass tube for excimer UV lamps, wherein the difference between the minimum values is 0.5 mm or less, and the bending per 1000 mm in length is 1.5 mm or less. The difference between the maximum value and the minimum value of the outer diameter is 0.7 mm or less, the difference between the maximum value and the minimum value of the wall thickness is 0.3 mm or less, and the bending per 1000 mm in length is 0.7 mm or less. The synthetic quartz glass tube for excimer UV lamps of Claim 1. The composition for excimer UV lamp according to claim 1 or 2, wherein each element concentration of Li, Na, K, Ca, Mg, Ti, Fe, Ni, Cu, Cr, Mo, W, V is less than 5 wtppb. Quartz glass tube. The composition for excimer UV lamp according to claim 1 or 2, wherein each element concentration of Li, Na, K, Ca, Mg, Ti, Fe, Ni, Cu, Cr, Mo, W, V is less than 3 wtppb. Quartz glass tube. The composition for excimer UV lamp according to claim 1 or 2, wherein each element concentration of Li, Na, K, Ca, Mg, Ti, Fe, Ni, Cu, Cr, Mo, W, V is less than 1 wtppb. Quartz glass tube. 6. The excimer according to claim 1, wherein a spectral transmittance at a wavelength of 172 nm from an inner surface to an outer surface of a synthetic quartz glass tube having a wall thickness of 0.8 mm or more and 2.8 mm or less is 80% or more. Synthetic quartz glass tube for UV lamp. The synthetic quartz glass tube for excimer UV lamp according to claim 6, wherein the spectral transmittance is 83% or more. The synthetic quartz glass tube for excimer UV lamp according to any one of claims 1 to 7, wherein the synthetic quartz glass tube has an OH group concentration of 10 wtppm to 400 wtppm and a Cl element concentration of 30 wtppm or less. The synthetic quartz glass tube for excimer UV lamp according to any one of claims 1 to 8, wherein the concentration of Cl element in the synthetic quartz glass tube is 5 wtppm or less. For excimer UV lamps that emit vacuum ultraviolet light having a wavelength of 150 to 250 nm, the dimensions are 1000 mm or more, outer diameter is 10 mm or more and 50 mm or less, wall thickness is 0.8 mm or more and 2.8 mm or less, and the width is 0.5 mm on the surface. There are no scratches of 150 mm or more in length, the difference between the maximum value and the minimum value of the outer diameter is 1.4 mm or less, the difference between the maximum value and the minimum value of the wall thickness is 0.5 mm or less, and there is a bend per 1000 mm in length. A method for producing a synthetic quartz glass tube for excimer UV lamps having a thickness of 1.5 mm or less, wherein the variation rate of wall thickness is 1.8% or less, and the surface roughness is 18 μm or less. Fluctuation of the internal pressure and pulling speed in the tube from the set values so that the cylindrical quartz glass cylinder, which is the silica glass tube of, can be made to the specified diameter and wall thickness by the non-contact heating drawing method. Each performed Kanbiki while being maintained to within ± 5%, the production method of the excimer UV lamp synthetic quartz glass tube, characterized in that to produce an excimer UV lamp synthetic quartz glass tube. The difference between the maximum value and the minimum value of the outer diameter is 0.7 mm or less, the difference between the maximum value and the minimum value of the wall thickness is 0.3 mm or less, and the bending per 1000 mm in length is 0.7 mm or less. The manufacturing method of the synthetic quartz glass tube for excimer UV lamps of Claim 10. The composition for excimer UV lamp according to claim 10 or 11, wherein each element concentration of Li, Na, K, Ca, Mg, Ti, Fe, Ni, Cu, Cr, Mo, W, V is less than 5 wtppb. A method of manufacturing a quartz glass tube. The composition for excimer UV lamp according to claim 10 or 11, wherein each element concentration of Li, Na, K, Ca, Mg, Ti, Fe, Ni, Cu, Cr, Mo, W, V is less than 3 wtppb. A method of manufacturing a quartz glass tube. The composition for excimer UV lamp according to claim 10 or 11, wherein each element concentration of Li, Na, K, Ca, Mg, Ti, Fe, Ni, Cu, Cr, Mo, W, V is less than 1 wtppb. A method of manufacturing a quartz glass tube. The excimer according to any one of claims 10 to 14, wherein a spectral transmittance at a wavelength of 172 nm from an inner surface to an outer surface of a synthetic quartz glass tube having a wall thickness of 0.8 mm or more and 2.8 mm or less is 80% or more. A method for producing a synthetic quartz glass tube for a UV lamp. 16. The method for producing a synthetic quartz glass tube for excimer UV lamps according to claim 15, wherein the spectral transmittance is 83% or more. The method for producing a synthetic quartz glass tube for an excimer UV lamp according to any one of claims 10 to 16, wherein an OH group concentration in the synthetic quartz glass tube is 10 wtppm or more and 400 wtppm or less, and a Cl element concentration is 30 wtppm or less. The method for producing a synthetic quartz glass tube for excimer UV lamps according to any one of claims 10 to 17, wherein the concentration of Cl element in the synthetic quartz glass tube is 5 wtppm or less.

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