JP4134927B2 - Excimer lamp - Google Patents

Description

  The present invention relates to an excimer lamp.

  2. Description of the Related Art In recent years, for example, a technique for treating a target object by irradiating the target object made of metal, glass, or other material with vacuum ultraviolet rays having a wavelength of 200 nm or less, by the action of the vacuum ultraviolet light and ozone generated thereby. A cleaning processing technology for removing organic contaminants adhering to the surface of the processing object and an oxide film forming processing technology for forming an oxide film on the surface of the processing object have been developed and put into practical use.

  As a lamp for performing such ultraviolet treatment, an excimer lamp in which an appropriate excimer emission gas is filled in a discharge vessel made of quartz glass is used.

By using, for example, xenon gas as the excimer light emission gas used in this excimer lamp, vacuum ultraviolet light having a peak at a wavelength of 172 nm, which is mainly xenon excimer light, is emitted, and as excimer light emission gas, for example, argon. It is known that vacuum ultraviolet rays having a peak at a wavelength of 175 nm, which is mainly argon-chlorine excimer light, are emitted by using a mixed gas with chlorine gas.
Such excimer discharge lamps are described in Patent Document 1 and Patent Document 2.

  Such an excimer lamp has a problem that the quartz glass is distorted when vacuum ultraviolet rays or ultraviolet rays generated in the discharge space pass through the quartz glass forming the discharge vessel, and the glass is damaged early. It was.

In recent years, in order to prevent damage to quartz glass, which is a discharge vessel for high-pressure discharge lamps and ultraviolet lamps, that is, to prevent mechanical strength from being lowered due to ultraviolet distortion and to prevent transmittance from being lowered, by setting the virtual temperature to an optimum range, It has been proposed to improve those problems.
Specifically, Patent Document 3 and Patent Document 4 describe that ultraviolet damage is reduced when the fictive temperature of quartz glass is set to about 500 to 1300 ° C. In particular, Patent Document 3 describes an excimer lamp. It is described that glass is also effective.

Patent No. 2951139 Japanese Patent No. 2775695 Japanese Patent Laid-Open No. 9-244103 JP-A-8-026764

  However, even when an excimer lamp as a discharge vessel is manufactured using such a quartz glass material, it may be damaged before reaching the target life.

  For example, in the case of a long excimer lamp exceeding 1 m, a long glass tube material is used to process the discharge vessel. However, since the glass tube material is not necessarily straight, centering by heat processing using a burner or the like is required. Or, when manufacturing a discharge vessel as a long glass tube by connecting a plurality of short glass tubes, a glass tube with an appropriate virtual temperature was used in advance by partially heating and bonding the short glass tube. Even so, the fictive temperature of the processed part becomes high and the processed part may be damaged.

  In addition, even when a glass tube with an appropriate virtual temperature is used in advance to form a discharge vessel for an excimer lamp, it may be damaged from the end of the discharge vessel if it is lit for a long time or is a high-power lamp. was there. This is because the discharge vessel is manufactured by sealing both ends of the glass tube material by heat processing using a burner, etc., but the heat-processed portion is affected by heat even if glass tube material at an appropriate virtual temperature is used in advance. In response, the fictive temperature rises and breaks from that part.

  Further, the excimer lamp has a problem in that blackened matter adheres to the inner surface of the discharge vessel, and the irradiance maintenance rate decreases. In addition, there is a problem that a high-intensity arc-like discharge is generated due to the blackened matter, and the light output is greatly reduced, or the fluctuation of the light amount increases due to the arc-like discharge moving around.

  For this reason, it is impossible to reliably prevent the discharge vessel from being damaged, and the irradiance maintenance rate is reduced in a short time. There was a problem that the amount of light fluctuated.

  The present invention has been made based on the above circumstances, and its purpose is that the discharge vessel of the excimer lamp is not damaged by ultraviolet rays, and the irradiance maintenance rate is maintained even if it is lit for a long time. An object of the present invention is to provide an excimer lamp that is not attenuated, does not decrease light output, and has a stable light quantity.

  In the excimer lamp according to claim 1 of the present invention, the fictive temperature of the glass of the light emitting part of the discharge vessel of the excimer lamp is 900 to 1200 ° C., and the amount of carbon (C) contained in the glass of the discharge vessel is The C / Si ratio is 0.1 atm% or less.

  The excimer lamp according to claim 2 is the excimer lamp according to claim 1, and in particular, the fictive temperature of the sealing wall portion formed by heat processing at both ends of the discharge vessel is 900 to 1200 ° C. It is characterized by that.

  An excimer lamp according to a third aspect is the excimer lamp according to the first or second aspect, and in particular, an exhaust pipe remainder is formed in the discharge vessel, and a virtual temperature of the exhaust pipe remainder is 900. It is -1200 degreeC.

  According to the excimer lamp of the present invention, the light emitting part and the sealing wall part of the discharge vessel constituting the excimer lamp are not easily distorted by ultraviolet rays even when the excimer lamp is lit, and the discharge vessel can be prevented from being damaged and discharged. Blackened material does not adhere to the inner surface of the container, and a decrease in the irradiance maintenance rate can be prevented, and the light output is greatly reduced and the discharge is stabilized without moving around.

Furthermore, when manufacturing the discharge vessel, the exhaust pipe remainder is formed by being cut off when the glass is in a high temperature state, and the fictive temperature is 1200 ° C. or higher in that state. However, after the exhaust pipe remainder is cut off, heat treatment is performed and the fictive temperature is set to 900 to 1200 ° C., so that distortion does not occur even when the exhaust pipe remainder is irradiated with ultraviolet rays. Breakage of the discharge vessel starting from the vicinity can be prevented.
Further, both ends of each of the outer tube and the inner tube constituting the discharge vessel are welded to each other by heat processing to form a sealing wall portion. The virtual temperature of the sealing wall portion is set to 900 to 1200 ° C. By doing so, even if the sealing wall portion is irradiated with ultraviolet rays, distortion does not occur, and the discharge vessel starting from the sealing wall portion can be prevented from being damaged.

Hereinafter, embodiments of the present invention will be described based on examples.
FIG. 1 is a diagram of an excimer lamp showing an embodiment of the present invention. In the figure, a discharge vessel 13 of an excimer lamp 1 has a cylindrical outer tube 11 made of quartz glass, and an outer diameter smaller than the inner diameter of the outer tube 11 disposed in the outer tube 11 along its cylinder axis. The inner tube 12 made of quartz glass and the both ends of each of the outer tube 11 and the inner tube 12 are welded to each other by heat processing to form a sealing wall portion 14, and the outer tube 11, the inner tube 12, A cylindrical discharge space S is formed between the two. The discharge space S of the discharge vessel 13 is filled with xenon gas as a luminescent gas.

  The outer tube 11 in the discharge vessel 13 is provided with one net-like electrode 16 made of a conductive material such as a wire mesh in close contact with the outer peripheral surface 15, and the outer peripheral surface 17 of the inner tube 12 is provided with the outer peripheral surface thereof. The other electrode 18 made of aluminum is provided so as to cover 17. The one electrode 16 and the other electrode 18 are connected to appropriate power supply devices (not shown) by current supply cords 19 and 19, respectively.

  Further, the discharge vessel 13 is formed with an exhaust pipe remaining portion a in which an exhaust pipe for sealing the luminescent gas in the discharge space S is cut off.

  The glass constituting the light emitting part of the discharge vessel 13 has a fictive temperature of 900 to 1200 ° C. Here, the “light emitting portion” refers to a discharge region of the discharge vessel 13 in a portion where the electrode 16 formed in close contact with the outer peripheral surface of the outer tube 11 indicated by a symbol L in FIG. Since the light emitting part is closest to the discharge generated in the discharge space and is easily distorted by ultraviolet rays, the fictive temperature of the light emitting part is very closely related to the breakage of the discharge vessel.

In addition, the “virtual temperature” referred to here is a scale indicating the structure of glass, and can also be referred to as a structure determining temperature. That is, the glass has a completely different structure depending on the heat treatment conditions. For example, when a glass in a thermal equilibrium state at a certain high temperature T is rapidly cooled to room temperature, the structure of the glass is frozen while the state at the temperature T is maintained. It is called temperature. Similarly, when glass in a thermal equilibrium state at a high temperature T is gradually cooled to room temperature rather than rapidly, the fictive temperature becomes a temperature close to room temperature.
Thus, the glass can be controlled to have various fictive temperatures according to the thermal equilibrium state and the cooling method therefrom, and the glass structure can be controlled variously.

  The calculation of the virtual temperature can be obtained by measuring an infrared absorption spectrum method or a Raman spectrum.

Specifically, an infrared absorption spectrum method was used for the fictive temperature of the arc tube portion. The infrared absorption spectrum method is a method of calculating the fictive temperature of quartz glass from the shift amount of the peak (near 2260 cm ⁻¹ ) indicating the stretching vibration of Si—O bond of quartz glass. A. Agarwal [Reference 1 Have found the following formula 1 for calculating the fictive temperature easily.

On the other hand, since the exhaust pipe remaining part and the sealing wall part have complicated surface shapes, they are greatly affected by reflection and scattering and cannot be measured by the infrared absorption spectrum method. Since the microscopic Raman spectrometer uses a backscattering method, measurement can be performed regardless of the surface shape. The method proposed by Geissberger [Reference 2] et al. Was used to calculate the fictive temperature of the glass from the Raman spectrum. A method of utilizing the shift amount of the line (peak appears in the vicinity of 440 cm ^-1) of omega ₁ due to the deformation vibration of Si-O-Si bonds in the quartz glass appear on the Raman signal of the quartz glass omega ₁ of The relationship between the peak position and the fictive temperature: T _f is expressed by the following equation (2).
The virtual temperature of the exhaust pipe remaining part and the sealing wall part was calculated from the measurement of the Raman spectrum.

Reference 1 A. Agarwal, K. M. Davis, M. Tomozawa, J. Non-Cryst. Solids 185 (1995). Reference 2 E. Geissberger and F. L. Galeener, Phys. Rev. B, 28 6 (1983) 3266.

An example of the conditions for the fictive temperature of the glass of the light emitting part of the discharge vessel to be 900 to 1200 ° C. is shown.
A discharge vessel body consisting of an outer tube, an inner tube and a sealing wall is manufactured in advance. In this state, the sealing tube formed in the discharge vessel is not sealed, and no luminescent gas is sealed in the discharge space of the discharge vessel.
This discharge vessel main body is placed in an electric furnace, heated at 1120 ° C. for 1 hour, and then rapidly cooled to 900 ° C. at a rate of 10 ° C./min. Can be manufactured.
As another method, the above-described discharge vessel main body is placed in an electric furnace, heated at 950 ° C. for 120 hours, and then gradually cooled to 700 ° C. at a rate of 0.1 ° C./min. A discharge vessel body made of glass at “° C.” can be produced.

That is, the fictive temperature of the light emitting part of the discharge vessel can be set to 900 to 1200 ° C. by performing such heat treatment.
In addition, by performing such heat treatment, the fictive temperature of the sealing wall portion other than the light emitting portion of the discharge vessel can be inevitably set to 900 to 1200 ° C.

  These are examples, and can be controlled so that the fictive temperature of the light emitting part of the discharge vessel and the glass of the sealing wall is 900 to 1200 ° C. under various other conditions.

  In this way, by setting the virtual temperature of the light emitting part and the glass of the sealing wall of the discharge vessel to 900 to 1200 ° C., the discharge vessel is less likely to be distorted by ultraviolet rays even if it is lit for a long time, preventing damage to the discharge vessel. can do.

Next, carbon (C) contained in the glass of the discharge vessel 13 will be described.
Hereinafter, the carbon (C) contained in the glass of the discharge vessel means carbon (C) contained in the glass of the entire discharge vessel body composed of the light emitting part, the sealing wall part, and the exhaust pipe remaining part described later. To do.

The reason why carbon is taken into the glass of the discharge vessel is not only the heat treatment during the glass manufacturing process and the molding using the carbon jig (to tubes and plates), but also the heat treatment and carbon jig during the lamp manufacturing process. The processing used can be considered.
Furthermore, as the time for heat treating the discharge vessel becomes longer, the amount of carbon taken into the glass of the discharge vessel increases.

When carbon comes into the discharge space from the inside of the glass in the state of CO or CO ₂ , it is decomposed by the plasma in the discharge space, and carbon adheres to the glass surface, reducing the transmittance and reducing the irradiance maintenance rate. Problems arise.
Furthermore, carbon adhering to the glass surface exhibits electrical conductivity, and a high-intensity arc-like discharge occurs, resulting in a significant decrease in light output, and fluctuations in the amount of light increase due to the arc-like discharge moving around. Problems arise.
Therefore, since the glass constituting the discharge vessel is substantially free of carbon (C), it is possible to prevent a decrease in irradiance maintenance rate, a decrease in light output, and a change in light amount.

  At that time, if the amount of carbon (C) in the glass constituting the discharge vessel is 0.1 atm% or less in terms of C / Si, the amount of carbon (C) released into the discharge space is reduced. The amount of carbon adhering to the glass surface is remarkably small, and the decrease in the transmittance of the glass can be surely prevented and the decrease in the irradiance maintenance factor can be prevented. In addition, a high-brightness arc-shaped discharge does not occur, the light output does not decrease, and the variation in light quantity can be reduced.

A specific method for measuring the carbon content will be described. A fluorescent X-ray analyzer was used to determine the amount of carbon. The inside of the glass of the discharge vessel is measured by vacuum in order to prevent the detection sensitivity of carbon inside the glass from being affected by the influence of carbon adhering to the lamp surface and of carbon floating in the atmosphere. A glass sample was broken in a chamber and its fracture surface was measured without exposure to the atmosphere.
Since it is considered that there is a distribution of carbon content in the thickness direction, measurements were made at a total of three points, 0.1 mm from the inner and outer surfaces, and the central portion of the thickness, and the average value was used as the actual measurement value. The lower limit of detection was 0.1 atm%, and the data below the detection limit value was 0, and the average value was obtained.

  Next, a number of excimer lamps with different fictive temperatures of glass and carbon (C) that make up the discharge vessel were manufactured. The breakage rate of the discharge vessel with the lapse of lighting time, and the ultraviolet irradiance at the time of initial lighting. An experiment was conducted to examine the ultraviolet irradiance maintenance rate after 1000 hours from lighting when the value is 100%. The excimer lamp is an excimer lamp shown in FIG. 1. The discharge vessel glass is quartz glass, the outer tube has an outer diameter of 25 mm, a wall thickness of 1 mm, the inner tube has an outer diameter of 12 mm, a wall thickness of 1 mm, and a total length (sealing walls at both ends). (Distance between parts) 800 mm, rated 500 W. Then, 30 kPa of Xe gas was sealed as a discharge gas in the discharge vessel.

  FIG. 2 shows experimental results and experimental conditions. The glass constituting the discharge vessel is composed of five excimer lamps having the same virtual temperature and the same carbon content as one group, and the virtual temperature between the groups, or The breakage rate of the discharge vessel of the excimer lamps of the seven A to G groups with different carbon content ratios (ratio indicating how many of the five lamps belonging to one group were damaged) and the irradiance An experiment was conducted to examine the maintenance factor (average irradiance maintenance factor of five lamps belonging to one group).

As shown in FIG. 2, in the excimer lamps of group A, the fictive temperature of the light emitting part and the sealing wall part of the discharge vessel is 800 ° C., and the carbon content (C / Si) is 0.2 atm%.
In this group A, all the lamps were not damaged even after 2000 hours from lighting. However, the irradiance maintenance rate was 59%.

  That is, since the fictive temperature is as low as 800 ° C., ultraviolet distortion is difficult to enter and the discharge vessel is not damaged. However, in order to control the fictive temperature to 800 ° C., it is necessary to place the discharge vessel in an electric furnace for a long time and apply heat treatment, or gradually cool the discharge vessel that has reached a high temperature state over time. Since this heat treatment process takes a long time, a large amount of carbon is mixed in the glass constituting the discharge vessel, and the carbon content (C / Si) is 0.2 atm% of 0.1 atm% or more. Thus, as a result of a large amount of carbon contained in the glass of the discharge vessel, there was a problem that blackened material adhered to the inner surface of the discharge vessel at an early stage and the irradiance maintenance rate was lowered.

  In addition, although one lamp out of five lamps does not break, a high-intensity arc-shaped discharge occurs when 1800 hours have elapsed, and another lamp has a point when 1900 hours have elapsed. A high-intensity arc-like discharge occurred. The high-intensity arc-shaped discharge moved around, and the temporal change in the amount of light at the same position fluctuated significantly. Specifically, the light output was attenuated to a range of about 3/4 to 1/4 when stable.

In the group F excimer lamp, the fictive temperature of the light emitting part and the sealing wall of the discharge vessel is 1300 ° C., and the carbon content (C / Si) is 0.1 atm% or less.
In this group F, 40% of the excimer lamp discharge vessel was damaged in 1000 hours after lighting, and the failure rate increased with the passage of lighting time. Finally, the failure rate reached 100% in 2000 hours. Was damaged. On the other hand, the irradiance maintenance factor showed a low value of 50%. This is because the carbon content of the glass of the discharge vessel is small and there is no influence by blackened material, but the transmittance of the glass of the discharge vessel itself decreases due to solarization etc., resulting in a decrease in the irradiance maintenance rate. is there.

  In group G, the fictive temperature of the light emitting part of the discharge vessel and the glass of the sealing wall is 1300 ° C., and 1000 hours after lighting, all the discharge vessels of the excimer lamp are damaged due to the distortion of ultraviolet rays. The lamp cannot be used.

  On the other hand, the excimer lamps belonging to the groups B to E of the present invention are excimer lamps that have a breakage rate of 0% even after 2000 hours have elapsed after lighting, and that do not break the discharge vessel even when lighted for a long time. In addition, since the carbon content (C / Si) is 0.1 atm% or less, no blackened matter adheres to the inner surface of the discharge vessel, the ultraviolet irradiance does not decrease, and the irradiance is maintained even if the lamp is lit for a long time. The maintenance rate does not decrease.

From this result, the fictive temperature of the glass of the light emitting part and the sealing wall part of the discharge vessel of the excimer lamp is 900 to 1200 ° C., and the amount of carbon (C) contained in the glass of the discharge vessel is C / Si. When the ratio is 0.1 atm% or less, even if the lamp is lit for a long time, the discharge vessel is not damaged by ultraviolet distortion, and the excimer lamp is less likely to have a reduced irradiance maintenance rate.
Further, no arc discharge with high brightness was generated, and the light output and light quantity did not fluctuate even after 2000 hours of lighting, and the discharge was stable.

Next, the fictive temperature of the light emitting part of the discharge vessel and the glass of the sealing wall is 1100 ° C. which is within the condition range of the present invention, and the four excimer lamps having different carbon contents are used for lighting for 1000 hours. An experiment was conducted to investigate changes in the irradiance maintenance rate.
The method of making the fictive temperature the same and making the carbon content different depends on, for example, the heat treatment method of the discharge vessel body. In the case of this experiment, the discharge vessel body was placed in an electric furnace at 1100 ° C for a long time and heat treatment was applied to discharge from the environment where the furnace wall, fixing jig and furnace were installed. The amount of carbon incorporated into the glass of the container was changed. Experiments were performed in which the carbon content (C / Si) was varied by changing the heat treatment time, and the influence of carbon was noticeable.
The results are shown in FIG.

As shown in FIG. 3, in the lamp 1 and the lamp 2, the amount of carbon (C) contained in the glass of the discharge vessel is 0.1 atm% or less in terms of the C / Si ratio, so the irradiance maintenance rate is 70% or more. Thus, an excimer lamp that maintains a high ultraviolet radiation maintenance rate and is less likely to cause a decrease in irradiance even when lit for a long time.
However, in the lamp 3 and the lamp 4, the amount of carbon (C) contained in the glass of the discharge vessel is 0.1 atm% or more in the C / Si ratio, so the irradiance maintenance ratio is less than 70%, and the radiation is maintained. If the lamp is lit for a long period of time, the irradiance of ultraviolet rays will decrease, resulting in an unusable lamp.
All the lamps were lit for 2000 hours, but no lamp was damaged because the virtual temperature was appropriate. Further, after the lamp 3 was lit for 1900 hours, a high-intensity arc-shaped discharge was generated, and after the lamp 4 was lit for 1600 hours, a high-luminance arc-shaped discharge was generated and the discharge was not stable.

Next, the exhaust pipe remainder of the discharge vessel will be described.
As described above, the glass fictive temperature control processing method of the discharge vessel performs heat treatment in a state in which an exhaust pipe that is not sealed off is formed on the discharge vessel body.
This is because when the discharge vessel body is sealed in the discharge vessel body, the exhaust tube is sealed and the exhaust tube remainder is formed, and the discharge vessel body is heated in an electric furnace, the internal emission gas expands and the discharge vessel body , The gas is filled in the discharge vessel in advance, and the discharge vessel including the remainder of the exhaust pipe is controlled so that the virtual temperature is in the range of 900 to 1200 ° C. with the discharge vessel completely completed. It is something that cannot be done. Depending on the pressure of the sealed gas, a large amount of oxygen, hydrogen, water, carbon, etc. is released from the glass into the discharge vessel, which adversely affects the discharge.
As a result, the work of sealing off the sealing pipe inevitably occurs after the virtual temperature control processing step, and the work of cutting off the sealing pipe is burned out at a high temperature. The temperature is 1200 ° C. or higher.

  Thus, when only the exhaust pipe remaining portion has a fictive temperature of 1200 ° C. or higher, when the exhaust pipe remaining portion is irradiated with ultraviolet rays, the exhaust pipe remaining portion is distorted by the ultraviolet rays, and the discharge vessel is discharged from the exhaust pipe remaining portion or the vicinity thereof. There is a risk of damage.

  In order to prevent this, only the exhaust pipe remaining part formed in the discharge vessel main body is separately heat-treated with a burner, or only the vicinity of the exhaust pipe residual part is heat-treated with an electric furnace or the like, thereby Heat treatment is performed so that the temperature becomes 900 to 1200 ° C. As a result, the fictive temperature of the glass of the entire discharge vessel including the exhaust pipe remainder becomes 900 to 1200 ° C., and the discharge vessel can be reliably prevented from being damaged by ultraviolet rays. In addition, since the heating range is small, the amount of impure gas (oxygen, hydrogen, water, carbon, etc.) released into the discharge vessel is small and does not affect the discharge, or the amount is so small that it can enter the unheated part of the discharge vessel It is adsorbed by the provided getter material and can generate a stable discharge.

FIG. 4 is an explanatory diagram of another excimer lamp.
In FIG. 4, the discharge vessel 20 has a tube-type sealed both ends structure made of quartz glass, an internal electrode 21 is disposed inside the discharge vessel 20, and a coiled external electrode is disposed on the outer surface of the discharge vessel 20. 22 is arranged, and excimer discharge is generated in the discharge space S by the discharge occurring between the internal electrode 21 and the external electrode 22 through the wall of the glass discharge vessel 20.
This discharge vessel had an outer diameter of 15 mm, a wall thickness of 1 mm, and 40 kPa of Xe gas was enclosed as a discharge gas in the discharge vessel.

  In such an excimer lamp, the entire discharge vessel 20 including the sealing portions 2a at both ends may be heat-treated so that the fictive temperature of the glass becomes 900 to 1200 ° C. Even if heat treatment is performed so that only the light emitting portion of the discharge vessel at the position where the electrode 22 is present has a fictive temperature of 900 to 1200 ° C., generation of distortion due to ultraviolet rays can be sufficiently suppressed. Since the exhaust pipe remaining part 2b is attached to the light emitting part, the exhaust pipe residual part 2b and the vicinity thereof are partially heat-treated so that the fictive temperature becomes 900 to 1200 ° C. after the discharge gas is sealed.

This suppresses the distortion of the light emitting portion that is closest to the discharge generated in the discharge space and is likely to be distorted by ultraviolet rays, thereby extending the life of the excimer lamp to a level that does not cause a problem in practice.
In addition, the quantity of carbon (C) contained in the glass which comprises the discharge vessel 20 is 0.1 atm% or less by the ratio of C / Si.

FIG. 5 is an explanatory diagram of another excimer lamp.
In FIG. 5, the discharge vessel 30 has a tube-type one-end sealed structure made of quartz glass, an internal electrode 31 is disposed inside the discharge vessel 30, and a wire mesh external electrode is disposed on the outer surface of the discharge vessel 30. 32 is arranged, and excimer discharge is generated in the discharge space S by the discharge occurring between the internal electrode 31 and the external electrode 32 through the wall of the glass discharge vessel 30.
This discharge vessel had an outer diameter of 40 mm, a wall thickness of 1 mm, and Xe gas as a discharge gas was sealed at 25 kPa in the discharge vessel.

  In such an excimer lamp, the entire discharge vessel 30 including the sealing portion 3a is heat-treated so that the fictive temperature of the glass is 900 to 1200 ° C., and the fictive temperature is also 900 to 1200 ° C. in the vicinity of the exhaust pipe remaining portion 3b. However, even in the case where only the light emitting part of the discharge vessel at the position where the external electrode 32 indicated by the symbol L is present in FIG. Generation of distortion can be sufficiently suppressed.

This suppresses the distortion of the light emitting portion that is closest to the discharge generated in the discharge space and is likely to be distorted by ultraviolet rays, thereby extending the life of the excimer lamp to a level that does not cause a problem in practice.
In addition, the quantity of carbon (C) contained in the glass which comprises the discharge vessel 20 is 0.1 atm% or less by the ratio of C / Si.

FIG. 6 is an explanatory diagram of another excimer lamp.
In FIG. 6, the discharge vessel 40 has a tube-shaped both-end sealed structure made of quartz glass, is substantially U-shaped, and an internal electrode 41 is disposed inside the discharge vessel 40. An external electrode 42 that also serves as a reflecting mirror is disposed on the outer surface of the straight tube portion 40 so as to cover half of the circumference, and the internal electrode 41 and the external electrode 42 are connected to each other through the wall of the glass discharge vessel 40. Excimer discharge is generated in the discharge space S due to discharge occurring between them.
The discharge vessel had an outer diameter of 20 mm, a wall thickness of 1 mm, and 20 kPa of Xe gas as a discharge gas was sealed in the discharge vessel.

In such an excimer lamp, the entire discharge vessel 40 including the sealing portion 4a is heat-treated so that the fictive temperature of the glass is 900 to 1200 ° C., and the fictive temperature is also 900 to 1200 ° C. in the vicinity of the exhaust pipe remaining portion 4d. However, the fictive temperature is 900 to 1200 ° C. only in the light emitting part forming the straight tube part 4b of the discharge vessel at the position where the external electrode 42 indicated by the symbol L in FIG. Thus, even when heat treatment is performed, the occurrence of distortion due to ultraviolet rays can be sufficiently suppressed.
In addition, such a substantially U-shaped discharge vessel arranges the curved tube portion 4c and the straight tube portion 4b as a whole in the electric furnace before the discharge gas is filled, and inevitably the curved tube portion 4c is virtual. The temperature is also 900 to 1200 ° C.

In other words, the life of the excimer lamp can be extended to such an extent that it does not cause a practical problem by suppressing the distortion of the light emitting portion that is closest to the discharge generated in the discharge space and is likely to be distorted by ultraviolet rays.
In addition, the quantity of carbon (C) contained in the glass which comprises the discharge vessel 40 is 0.1 atm% or less by ratio of C / Si.

FIG. 7 is an explanatory diagram of another excimer lamp.
In FIG. 7, the discharge vessel 50 has a tube-type one-end sealed structure made of quartz glass, has a spiral shape, and an internal electrode 51 is disposed inside the discharge vessel 50. A wire net-like external electrode 52 is arranged on the outer surface, and excimer discharge is generated in the discharge space S due to discharge between the internal electrode 51 and the external electrode 52 through the wall of the glass discharge vessel 50. To do.
This discharge vessel had an outer diameter of 15 mm, a wall thickness of 1 mm, and 40 kPa of Xe gas was enclosed as a discharge gas in the discharge vessel.

  In such an excimer lamp, the entire discharge vessel 50 including the sealing portion 5a may be heat-treated so that the fictive temperature of the glass becomes 900 to 1200 ° C., but the position where the external electrode 52 exists in FIG. Even if only the light emitting part forming the spiral part 5b of the discharge vessel is heat-treated so that the fictive temperature is 900 to 1200 ° C., the occurrence of distortion due to ultraviolet rays can be sufficiently suppressed. Since the exhaust pipe remaining portion 5c is attached to the light emitting portion, the exhaust pipe remaining portion 5c and the vicinity thereof are partially heat-treated so that the fictive temperature becomes 900 to 1200 ° C. after the discharge gas is sealed.

  In addition, the quantity of carbon (C) contained in the glass which comprises the discharge vessel 50 is 0.1 atm% or less by ratio of C / Si.

FIG. 8 is an explanatory diagram of another excimer lamp.
In FIG. 8, the discharge vessel 60 has a both-end sealed structure made of glass, and a pair of external electrodes 61 are arranged inside the discharge vessel 60, and the glass discharge vessel 60 is interposed through the wall. Excimer discharge is generated in the discharge space S by the discharge occurring between the external electrodes 61.

  In such an excimer lamp, the entire discharge vessel 60 may be heat-treated so that the fictive temperature of the glass becomes 900 to 1200 ° C. However, only the light emission part of the discharge vessel at the position where the external electrode 61 exists has a fictive temperature. Even if it heat-processes so that it may become 900-1200 degreeC, generation | occurrence | production of the distortion by an ultraviolet-ray can fully be suppressed.

This suppresses the distortion of the light emitting portion that is closest to the discharge generated in the discharge space and is likely to be distorted by ultraviolet rays, thereby extending the life of the excimer lamp to a level that does not cause a problem in practice.
Note that the amount of carbon (C) contained in the glass constituting the discharge vessel 60 is 0.1 atm% or less in terms of the C / Si ratio.

Next, when the sealing portion 2a of the excimer lamp shown in FIG. 4 is heated in an electric furnace so that the virtual temperature becomes 900 to 1200 ° C., the external lead rod protruding from the sealing portion 2a is not oxidized. An example is shown in FIG.
FIG. 9 (a) The metal foil H and the external lead rod G are located in the inside of the discharge vessel 20 and slightly in the center from the end, and the metal foil H and the external lead rod G are previously placed at this position e. In addition, the end f of the discharge vessel 20 is sealed, and the space A is kept in a vacuum or an inert gas atmosphere.

In this state, the entire discharge vessel 20 including the sealing portion 2a is placed in an electric furnace and heated so that the fictive temperature is 900 to 1200 ° C.
As a result, the external lead rod G can be prevented from being oxidized by oxygen present in the electric furnace.
Thereafter, the portion indicated by XX in FIG. 9A is cut to expose the external lead rod G to the outside as shown in FIG.
It should be noted that the oxidation of the external lead rod can be prevented by making the sealing portions 3a, 4a, and 5a of FIGS.
Naturally, oxidation can be prevented even if the inside of the electric furnace is in a vacuum or an inert atmosphere and a lamp with an exposed external lead bar is inserted.

  Glass distortion is generated by ultraviolet rays or vacuum ultraviolet rays, but vacuum ultraviolet rays having a short wavelength are more likely to occur. The embodiment of the present invention has been described mainly with respect to an Xe excimer lamp encapsulating Xe gas that emits vacuum ultraviolet light of 172 nm. The same effect can be obtained with a wavelength of 175 nm, which is argon-chlorine excimer light. Further, even in a mixed gas such as xenon-chlorine and krypton-fluorine, ultraviolet rays of 308 nm and 248 nm are mainly generated, but since 172 nm of xenon and 147 nm of vacuum ultraviolet light of krypton are also generated, distortion is likely to occur. In particular, when the lamp is lit for a long time, a halogen gas depletion phenomenon occurs, and the ratio of vacuum ultraviolet light increases at the end of the lifetime.

It is explanatory drawing of the excimer lamp of this invention. It is an experimental result data explanatory drawing which investigated the fracture | rupture rate of the discharge vessel at the time of changing the virtual temperature of the glass which comprises the discharge vessel of an excimer lamp, and the quantity of carbon (C), and an ultraviolet irradiance maintenance factor. It is experiment result data explanatory drawing which investigated the change of the irradiance maintenance factor when changing the carbon content in the case where the fictive temperature of the discharge vessel is constant. It is explanatory drawing of the other Example of the excimer lamp of this invention. It is explanatory drawing of the other Example of the excimer lamp of this invention. It is explanatory drawing of the other Example of the excimer lamp of this invention. It is explanatory drawing of the other Example of the excimer lamp of this invention. It is explanatory drawing of the other Example of the excimer lamp of this invention. It is explanatory drawing of the oxidation prevention method of the external lead rod of the excimer lamp of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Excimer lamp 11 Outer tube 12 Inner tube 13 Discharge vessel 14 Sealing wall part 15 Outer tube outer peripheral surface 16 Electrode 17 Inner tube outer peripheral surface 18 Electrode 19 Power supply code a Exhaust pipe remainder

Claims (3)

The fictive temperature of the glass of at least the light emitting part of the discharge vessel of the excimer lamp is 900 to 1200 ° C.,
An excimer lamp characterized in that the amount of carbon (C) contained in the glass of the discharge vessel is 0.1 atm% or less in a C / Si ratio. 2. The excimer lamp according to claim 1, wherein a fictive temperature of a sealing wall portion formed by heat processing at both ends of the discharge vessel is 900 to 1200 ° C. 3. The excimer lamp according to claim 1 or 2, wherein an exhaust pipe remainder is formed in the discharge vessel, and a virtual temperature of the exhaust pipe remainder is 900 to 1200 ° C.

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