JP2009104924A - Extreme ultraviolet light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase current density of discharge current to increase light emitting intensity and luminance of EUV light and to converge the EUV light to increase exposure accuracy. <P>SOLUTION: An extreme ultraviolet light source device includes means 18 supplying EUV light radiating raw material such as a liquid into a vessel 1, means 3 irradiating the raw material with energy beams to evaporate it, a pair of discharge electrodes 6, 9 apart from each other by a predetermined distance to heat and energize the evaporated raw material by discharge to generate high-temperature plasma, means 17 supplying pulse power between the discharge electrodes, means 14 converging the EUV light radiated from the high-temperature plasma generated by discharge between the discharge electrodes and a take-out part 15 taking out the converged EUV light. The pair of discharge electrodes 6, 9 are disc-shaped discharge electrodes rotated by a rotating mechanism connected thereto and a plurality of protrusions 7, 10 are formed on a peripheral edge part of at least one of the disc-shaped discharge electrodes at positions opposed to the other discharge electrode. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an extreme ultraviolet light source device that generates extreme ultraviolet light, and more particularly to an extreme ultraviolet light source device that generates extreme ultraviolet light while rotating an electrode.

  With the miniaturization and high integration of semiconductor integrated circuits, improvement in resolving power is demanded in the projection exposure apparatus for production. In order to meet the demand, the exposure light source has been shortened, and as a next-generation semiconductor exposure light source following the excimer laser apparatus, extreme ultraviolet light (hereinafter referred to as EUV (hereinafter referred to as EUV)) having a wavelength of 13 to 14 nm, particularly 13.5 nm. Extreme ultraviolet light source devices (hereinafter also referred to as EUV light source devices) have been developed that emit light (also referred to as Extreme Ultra Violet) light.

  There are several known methods for generating EUV light in an EUV light source apparatus. One of them generates high-temperature plasma by heating and exciting EUV radiation species, and EUV light emitted from this plasma is emitted. There is a way to take out. As EUV light source apparatuses adopting such a method, an LPP (Laser Produced Plasma) type EUV light source apparatus and a DPP (Discharge Produced Plasma) type EUV light source apparatus are produced by a high temperature plasma generation system. And can be broadly divided. The LPP EUV light source device generates high-temperature plasma by irradiating a target of solid, liquid, gas or the like with a pulse laser. On the other hand, the DPP EUV light source device generates high-temperature plasma by current drive.

  In EUV light source devices, Xe (xenon) ions of about 10 valence are currently known as radioactive species that emit EUV light with a wavelength of 13.5 nm, that is, as a raw material for high-temperature plasma. Li (lithium) ions and Sn (tin) ions have attracted attention as raw materials for obtaining strong radiation intensity. For example, Sn has a conversion efficiency that is a ratio of the EUV light emission intensity with a wavelength of 13.5 nm to the input energy for generating high temperature plasma several times larger than Xe.

  Patent Documents 1 and 2 propose a device that rotates an electrode as a DPP type EUV light source device in order to prevent the electrode from being consumed.

FIG. 11 is a cross-sectional view showing the configuration of the EUV light source device shown in FIG.
In the figure, 101 and 102 are disk-shaped electrodes, 103 and 104 are rotating shafts for rotating the electrodes 101 and 102, respectively, and 105 is heated as a raw material for high-temperature plasma into which a part of the electrodes 101 and 102 is immersed. Liquid metal or molten metal. The liquid metal 105 riding on the surfaces of the electrodes 101 and 102 with the rotation of the electrodes 101 and 102 is carried to a preset gap which becomes the discharge part 106 between the electrodes 101 and 102, and the carried liquid. The metal beam 105 is irradiated with a laser beam 107 and vaporized. Next, a discharge voltage is applied through the metal 105 vaporized between the electrodes 101 and 102. When the discharge voltage is applied, discharge is started in the discharge unit 106, and high-temperature plasma is generated. EUV light generated from the high temperature plasma is extracted from the upper side of the drawing.

When the discharge electrodes 101 and 102 are rotated as in the above EUV light source device, there are the following advantages. That is, a solid or liquid raw material for high-temperature plasma that is a raw material of a new EUV generation species can always be supplied to the discharge unit 106 formed between the electrodes 101 and 102. Further, since the position of the electrodes 101 and 102 where the laser beam 107 is irradiated, that is, the position of the discharge portion 106 where the high temperature plasma is generated constantly changes, the thermal load on the electrodes 101 and 102 is reduced, and the electrodes 101 and 102 are consumed. Can be prevented.
Special table 2007-505460 gazette WO2005 / 101924

  However, the EUV light source device disclosed in Patent Document 1 has the following problems. That is, in order to improve the EUV emission intensity and brightness from the high-temperature plasma, it is necessary to efficiently supply discharge energy to the plasma. For this purpose, a local concentrated electric field is generated in the discharge unit 106 to reduce the discharge current. It is necessary to increase the current density. However, in this apparatus, the discharge portion 106 is a so-called circumferential edge portion where the two disc-shaped electrodes 101 and 102 are close to each other, and the discharge is the portion where the edges of the electrodes 101 and 102 are closest to each other. Will occur. However, in an actual apparatus, the diameters of the disk-shaped electrodes 101 and 102 are large in consideration of the power supplied to the electrodes 101 and 102, the heat capacity of the electrodes 101 and 102, and the rotation speed (frequency) of the electrodes 101 and 102. There is no difference in the electrode spacing between the closest part of the edges of the electrodes 101 and 102 and the vicinity thereof.

  FIG. 3B, which will be described later, is an enlarged view of the discharge portion 106 of the disk-like electrodes 101, 102 of the EUV light source device. As an example, the electrodes 101 and 102 have a radius of about 350 mm, the gap length between the electrodes 101 and 102 is about 5 mm, and the discharge portion 106 is a region sandwiched between two circular electrodes 101 and 102. As shown in the figure, the outer peripheries of the electrodes 101 and 102 in the discharge portion 106 are substantially linear, and the gap length between the electrodes 101 and 102 hardly changes over the outer peripheries 10 mm to 20 mm of the electrodes 101 and 102. Therefore, the electric lines of force of the discharge part 106 are dispersed, the electric field is weakened, the current density of the discharge current is lowered, and the EUV emission intensity and luminance cannot be increased.

  Further, according to the EUV light source device, since the electric lines of force of the discharge unit 106 are dispersed, there is a high possibility that the spatial position of the discharge path (discharge current path) fluctuates. When the spatial position of the discharge path varies, the spatial position of the high-temperature plasma varies, and the position where EUV light is emitted also varies. When the position where the EUV light is emitted fluctuates, the focal point of the EUV light fluctuates, which affects the exposure accuracy. In order to prevent this, the spatial position of the plasma emitting EUV light must be stabilized. For this purpose, the electric field lines must be concentrated (a local concentrated electric field is generated) to fix the spatial position of the discharge path.

  In view of the above-mentioned problems of the prior art, an object of the present invention is to increase the EUV light emission intensity and brightness by increasing the current density of the discharge current in an EUV light source device having two disk-shaped rotating electrodes. Another object of the present invention is to provide an extreme ultraviolet light source device in which the EUV light emission position is fixed and the EUV light is focused to improve the exposure accuracy.

The present invention employs the following means in order to solve the above problems.
The first means includes a container, a raw material supply means for supplying a liquid or solid raw material for emitting EUV light into the container, and an energy beam irradiation for irradiating the raw material with the energy beam to vaporize the raw material. Means, a pair of discharge electrodes arranged at a predetermined distance to generate heat plasma by heating and exciting the vaporized material in the container by discharge, and supplying pulsed power between the discharge electrodes Pulse power supply means, condensing optical means for condensing extreme ultraviolet light emitted from the high-temperature plasma generated by discharge between the discharge electrodes, and extreme ultraviolet light extraction for extracting the collected extreme ultraviolet light And the pair of discharge electrodes are disk-shaped discharge electrodes that are rotated by a rotation mechanism connected thereto, and at least one of the disk-shaped discharge electrodes. A position opposed to the other of the discharge electrodes of the electrode of the periphery, is extreme ultraviolet light source device, wherein a plurality of protrusions are formed.
The second means is the extreme ultraviolet light source apparatus according to the first means, wherein the pair of disc-shaped discharge electrodes are arranged on substantially the same plane.
A third means is the extreme ultraviolet light source device according to the first means, wherein the pair of disc-shaped discharge electrodes are arranged in parallel on the same axis.
A fourth means is an extreme ultraviolet light source device according to any one of the first means to the third means, wherein the raw material supply means drops the raw material in the vicinity of the discharge electrode. is there.
A fifth means is the extreme ultraviolet light source device according to any one of the first means to the third means, wherein the raw material supply means applies the raw material to the surface of the discharge electrode. It is.
A sixth means is the extreme ultraviolet light source apparatus according to the fifth means, wherein the energy beam irradiating means irradiates the tip of the protrusion with an energy beam.
According to a sixth means, in any one of the first means to the sixth means, the interval between the protrusions formed on the peripheral edge portion of the discharge electrode is a discharge in which no protrusion facing the protrusion is formed. The extreme ultraviolet light source device is characterized in that the distance between the electrodes is closest or the distance between the protrusions formed on the discharge electrode facing the protrusion is wider than the closest distance.

According to the first to sixth aspects of the invention, when electric power is supplied to both the rotating electrodes, in the rotating electrode provided with the protrusions, the electric lines of force face each other between the two opposing protrusions or one protrusion. Therefore, when high temperature plasma is formed between the rotating electrodes, the current density increases between the protrusions or between the protrusions and the rotating electrode, and the emission intensity and luminance of EUV light emitted from the high temperature plasma is reduced. Can be high. In addition, since the lines of electric force are concentrated at the tips of the protrusions, if the plasma raw material is supplied and vaporized between the protrusions or between the protrusions and the rotating electrode, a discharge is generated only between the tips of the opposing protrusions. Extreme ultraviolet light will be emitted. As a result, the spatial position of the discharge path is fixed, and the emission position of extreme ultraviolet light can be stabilized.
According to the invention described in claim 7, the rotation (pitch) of the protrusions formed on the two rotating electrodes is made wider than the distance (gap) between the tips of the protrusions that are closest to each other. The electric lines of force between the projections of the electrodes can be concentrated between the tips of the projections closest to each other and the emission position of extreme ultraviolet light can be stabilized.

A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1A is a plan view showing a schematic configuration of the extreme ultraviolet light source device according to the present embodiment, and FIG. 1B is a configuration of a main part of the extreme ultraviolet light source device shown in FIG. FIG.
In these figures, 1 is a vacuum container in which a pair of rotating electrodes 6 and 9 are accommodated, 2 is a vacuum container in which an EUV collector mirror 14 and the like that collects emitted EUV light is accommodated, and 3 is an energy beam. Laser device as irradiation means, 4 is a laser beam, 5 is a laser incident window, 6 is one disk-shaped rotating electrode, 7 is a plurality of protrusions arranged at predetermined intervals on the outer peripheral edge of the rotating electrode 6, and 8 is rotating The rotation axis of the electrode 6, 9 is the other disk-shaped rotation electrode arranged on the substantially same plane as the rotation electrode 6 at a predetermined distance, and 10 is predetermined on the outer peripheral edge of the rotation electrode 9 so as to face the protrusion 7. , 11 is a rotation axis of the rotating electrode 9, 12 is a droplet target of high temperature plasma raw material, 13 is provided between the rotating electrodes 6 and 9 and the EUV collector mirror 14. Excluding generated debris , 14 is an EUV collector mirror as a condensing optical means, 15 is an EUV light exit window as an EUV light extraction unit, 16 is a gas exhaust unit, 17 is a pulse for supplying pulse power to the discharge electrodes 6 and 9. A pulse power source as a power supply means, 18 a discharge region, 19 a droplet supply device as a raw material supply means for supplying a liquid or solid raw material, and 20 a target recovery cylinder.

  As shown in these drawings, a raw material (for example, Sn) that generates high-temperature plasma is supplied dropwise from a droplet supply device 19 between the electrodes 6 and 9 as a liquid droplet. The dropped high temperature plasma raw material is vaporized by laser irradiation from the laser device 3, and at the same time, pulse power is supplied from the pulse power source 17 between the protrusion 7 of the rotating electrode 6 and the protrusion 10 of the rotating electrode 9 to start discharge. As a result, high-temperature plasma is formed by the raw material vaporized between the projections 7 and 9, and EUV light is emitted. The emitted EUV light is collected by the EUV collector mirror 14, and the EUV light is Is taken out from the EUV light exit window 15 provided in FIG.

FIG. 2A is a plan view of the rotating electrodes 6 and 9 as viewed from above (raw material supply side) in order to explain in detail the main part of the extreme ultraviolet light source device shown in FIG. These are the front views which look at the rotating electrodes 6 and 9 from the front (light emission side) in order to explain the principal part of the extreme ultraviolet light source device shown in FIG. 1 in detail.
As shown in these drawings, a pair (two) of disk-shaped rotating electrodes 6 and 9 are arranged side by side on the same plane, and the motors 21 and 22 are arranged via rotating shafts 8 and 11 of the rotating electrodes 6 and 9. Is attached and rotates about the rotation shafts 8 and 11. A plurality of projections 7 and 10 are formed at equal intervals on the peripheral edge of the rotating electrodes 6 and 9 (side surfaces of the rotating electrodes 6 and 9 facing each other). The rotating electrodes 6 and 9 are synchronously rotated at the same speed, and the protrusions 7 and 10 are designed in the discharge region 18 so that the tips of the protrusions 7 and 10 face each other at a predetermined interval and are closest to each other. Yes. The position where the electrodes 6 and 9 are closest to each other is the discharge region 18, and toward this discharge region 18 or the vicinity of the discharge region 18, as shown in FIG. From FIG. 2B, a liquid high-temperature plasma raw material such as Sn is dropped. When the dropped high temperature plasma raw material approaches (or reaches) the discharge region 18, as shown in FIG. 1B, the laser beam 14 is irradiated from the laser device 3 to the high temperature plasma raw material and is vaporized. At the same time, pulse power is supplied from the pulse power source 17 shown in FIGS. 1 (a) and 1 (b) to the rotating electrodes 6 and 9, and discharge is started. As a result, high-temperature plasma is formed between both electrodes, and EUV. Light is emitted.

FIG. 3A is an enlarged view of a discharge region 18 in which the rotating electrode 6 including the protrusion 7 and the rotating electrode 9 including the protrusion 10 face each other in the main configuration shown in FIGS. 2A and 2B. FIG. 3B is an enlarged view of a discharge region where the rotating electrode 101 and the rotating electrode 102 that do not have the protrusions according to the conventional technology face each other.
3 (a) and 3 (b), the design is made under the condition that the radius of the rotating electrode is 350 mm, the rotating speed of the rotating electrode is 50 Hz, the discharge repetition frequency is 10 kHz, and the electrode interval is 5 mm. The protrusions 7 and 10 are formed at an interval (pitch) of about 11 mm. In FIG. 3B, the rotation electrodes 101 and 102 are not provided with protrusions.

  The arrows in FIGS. 3A and 3B schematically show the electric lines of force of the electric field generated between the rotating electrodes when electric power is supplied to the rotating electrodes. 3A, in the rotating electrodes 6 and 9 including the protrusions 7 and 10, the electric lines of force are concentrated between the two opposing protrusions 7 and 10. Therefore, when high temperature plasma is formed between the rotating electrodes 6 and 9, the current density is increased between the protrusions 7 and 10, and the emission intensity and luminance of EUV light emitted from the high temperature plasma can be increased. Since the lines of electric force are concentrated at the tips of the projections 7 and 10, if the plasma raw material is supplied between the projections 7 and 10, a discharge is generated only between the tips of the opposing projections 7 and 10, EUV light is emitted from the position. That is, the spatial position of the discharge path is fixed, and the emission position of EUV light can be stabilized.

  The interval (pitch) between the projections 7 and 10 formed on the rotary electrodes 6 and 9 is made wider than the interval (gap) between the tips of the projections 7 and 10 that are closest to each other for the following reason. That is, when the interval (pitch) is narrower, the electric lines of force between the projections 7 and 10 of the rotary electrodes 6 and 9 are not only between the opposing projections 7 and 10 but also between the adjacent projections 7 and 10. There is a possibility of being concentrated between. Therefore, there is a possibility that the discharge is generated other than between the tips of the opposing protrusions 7 and 10, and in this case, the emission position of the EUV light becomes unstable. On the other hand, as shown in FIG. 3B, in the case of the rotating electrodes 101 and 102 not provided with the protrusions, since the diameters of the rotating electrodes 101 and 102 are large, the outer peripheries of the rotating electrodes 101 and 102 in the discharge portion are substantially linear. Thus, the distance between the rotating electrodes 101 and 102 hardly changes over 10 mm to 20 mm. Therefore, the electric lines of force in the discharge part are dispersed, the current density is lowered, and the EUV emission intensity and luminance are not increased. Moreover, since the electric lines of force of the discharge part are dispersed, the discharge path position fluctuates and the EUV light emission position is not stable.

Next, a second embodiment of the present invention will be described with reference to FIG.
4A is a plan view showing a schematic configuration of the extreme ultraviolet light source device according to the present embodiment, and FIG. 4B is a configuration of a main part of the extreme ultraviolet light source device shown in FIG. FIG.
In these figures, reference numeral 23 denotes a metal bus as a raw material supply means, and the other configurations correspond to the configurations of the same reference numerals shown in FIG.
As shown in these drawings, the extreme ultraviolet light source device according to the present embodiment uses a metal bath 23 instead of the droplet supply device 19 as the high temperature plasma raw material supply means shown in FIG. is there. A liquid high-temperature plasma raw material is stored in the metal bath 23, and one or both of the rotating electrodes 9 and 10 are immersed in the metal bath 23, and the rotating electrodes 6 and 9 rotate. A high temperature plasma raw material adheres to the surface of the protrusion 10 of the rotating electrode 9 that has passed through the metal bath 23.

  In the extreme ultraviolet light source device of the present embodiment, both the rotating electrodes 6 and 9 are rotated at the same speed synchronously, and the protrusions 7 and 10 are set in advance in the discharge region 18 at the tips of the protrusions 7 and 10. It is designed to face each other at a predetermined interval and come closest. The position where the projections 7 and 10 of the rotating electrodes 6 and 9 are closest is the discharge region 18. When the projection 10 to which the high-temperature plasma raw material is attached approaches (or reaches) the discharge region 18, the laser beam is emitted from the laser device 3. 11 is irradiated to the high temperature plasma raw material at the tip of the protrusion 10 and vaporized. At the same time, pulse power is supplied from the pulse power source 17 to the rotating electrodes 6 and 9 to start discharge between the projections 7 and 10, thereby forming high temperature plasma between the projections 7 and 10 and emitting EUV light. .

  Also in the extreme ultraviolet light source device of the present embodiment, when high-temperature plasma is formed between the rotating electrodes 6 and 9, the current density increases between the protrusions 7 and 10, and the emission intensity of EUV light emitted from the high-temperature plasma. And the brightness can be increased. Since the lines of electric force are concentrated at the tips of the projections 7 and 10, if the plasma raw material is supplied between the projections 7 and 10 and vaporizes, a discharge is generated only between the tips of the opposing projections 7 and 10. The EUV light is emitted from the position, the spatial position of the discharge path is fixed, and the emission position of the EUV light can be stabilized.

Next, a third embodiment of the present invention will be described with reference to FIGS.
FIG. 5A is a plan view showing a schematic configuration of the extreme ultraviolet light source device according to the present embodiment, and FIG. 5B is a configuration of a main part of the extreme ultraviolet light source device shown in FIG. FIG. 6A is a plan view of the disk-shaped rotating electrode as viewed from above, and FIG. 6B is a cross-sectional view as viewed from AA in FIG. 6A.
5A and 5B, reference numeral 24 denotes one disk-shaped rotating electrode, 25 denotes a plurality of protrusions arranged at predetermined intervals on the outer peripheral edge of the rotating electrode 24, and 26 is on the same axis as the rotating electrode 24. The other disk-shaped rotating electrode 27 arranged in parallel and spaced apart by a predetermined distance, 27 is a plurality of protrusions arranged at predetermined intervals on the outer peripheral edge of the rotating electrode 26 so as to face the protrusion 25. Other configurations correspond to the configurations of the same reference numerals shown in FIG.

  In the extreme ultraviolet light source device of the present embodiment, as shown in FIGS. 6A and 6B, the tips of the opposing protrusions 25 and 27 face each other at a predetermined interval (gap) set in advance. Designed. Further, for the same reason as described in the first embodiment, the interval (pitch) between the protrusions 25 and 27 formed on the rotary electrodes 24 and 26 is configured wider than the interval (gap) between the tips of the protrusions 25 and 27. . Between the two protrusions 25 and 27 is the discharge region 18, and liquid high-temperature plasma raw material such as Sn is dropped from the droplet supply device 19 disposed above toward the vicinity of the discharge region 18. When the dropped high temperature plasma raw material approaches the discharge region 18, the laser beam 4 is irradiated from the laser device 3 to the high temperature plasma raw material and vaporized. At the same time, pulse power is supplied from the pulse power supply 17 to the rotating electrodes 24 and 26 to start discharging, whereby high-temperature plasma is formed between the protrusions 25 and 27 and EUV light is emitted.

  Also in the extreme ultraviolet light source device of this embodiment, when high temperature plasma is formed between the rotating electrodes 24 and 26, the current density increases between the protrusions 25 and 27, and the emission intensity of EUV light emitted from the high temperature plasma. And the brightness can be increased. Since the electric lines of force are concentrated at the tips of the projections 25 and 27, if the vaporized plasma raw material is supplied between the projections 25 and 27, a discharge is generated only between the tips of the opposing projections 25 and 27, and the position The EUV light is emitted from the discharge path, the spatial position of the discharge path is fixed, and the emission position of the EUV light can be stabilized.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
FIG. 7A is a plan view showing a schematic configuration of the extreme ultraviolet light source device according to this embodiment, and FIG. 7B is a configuration of a main part of the extreme ultraviolet light source device shown in FIG. FIG.
In these drawings, 23 is a metal bath as a raw material supply means, 24 is one disk-shaped rotating electrode, 25 is a plurality of protrusions arranged at predetermined intervals on the outer peripheral edge of the rotating electrode 24, and 26 is a rotating electrode 24. The other disk-shaped rotary electrode 27 arranged in parallel on the same axis and spaced apart from each other by a predetermined distance 27 is a plurality of protrusions arranged at predetermined intervals on the outer peripheral edge of the rotary electrode 26 so as to face the protrusion 25. Other configurations correspond to the configurations of the same reference numerals shown in FIG.

  As shown in these drawings, in the extreme ultraviolet light source device according to the present embodiment, a liquid high-temperature plasma raw material is stored in the metal bath 23, and one or both of the rotating electrodes 24 and 26 have a part. The rotating electrodes 24 and 26 rotate by being immersed in the metal bath 23. A high temperature plasma raw material adheres to the surface of the protrusion 27 of the rotating electrode 26 that has passed through the metal bath 23.

  In the extreme ultraviolet light source device of this embodiment, the rotating electrodes 24 and 26 rotate at the same speed synchronously, and the protrusions 25 and 27 are predetermined in the discharge region 18 where the tips of the protrusions 25 and 27 are set in advance. Designed to face each other. Between the projections 25 and 27 of the rotating electrodes 24 and 26 is the discharge region 18, and the laser beam 4 is irradiated from the laser device 3 to the tip of the projection 27 to which the high-temperature plasma raw material adheres, and the high-temperature plasma raw material is vaporized. At the same time, pulse power is supplied from the pulse power source 17 to the rotating electrodes 23 and 25 to start discharging, whereby high temperature plasma is formed between the protrusions 25 and 27 and EUV light is emitted.

  Also in the extreme ultraviolet light source device of this embodiment, when high temperature plasma is formed between the rotating electrodes 24 and 26, the current density increases between the protrusions 25 and 27, and the emission intensity of EUV light emitted from the high temperature plasma. And the brightness can be increased. Since the lines of electric force are concentrated at the tips of the projections 25 and 27, if a plasma raw material is supplied between the projections 25 and 27 and vaporizes, a discharge is generated only in the vicinity of the tips of the opposing projections 25 and 27. The EUV light is emitted from the position, the spatial position of the discharge path is fixed, and the emission position of the EUV light can be stabilized.

In the extreme ultraviolet light source device according to each of the above embodiments, a plurality of protrusions are arranged at a predetermined interval on the outer peripheral edge of one disk-shaped rotating electrode, and are spaced apart from the one disk-shaped rotating electrode by a predetermined distance. A plurality of protrusions are also arranged at a predetermined interval on the outer peripheral edge of the other disk-shaped rotating electrode arranged in this manner, but it is also possible not to provide a protrusion on the outer peripheral edge of the other disk-shaped rotating electrode. .
FIG. 8 is a diagram showing lines of electric force when a protrusion is provided only on one of the pair of rotating electrodes. As shown in the figure, the electric field lines are less concentrated than when the protrusions are formed on both rotating electrodes, but the current density is higher than when the protrusions are not provided. The emission intensity and luminance of EUV light emitted from the plasma can be increased.

FIG. 9 is a diagram showing a control system in the extreme ultraviolet light source apparatus according to the first embodiment, and FIG. 10 is a diagram showing a time chart of the control system shown in FIG.
A piezoelectric element is vibrated by a high frequency signal (sine wave, frequency f ₀ ) of about 300 kHz from a high frequency oscillator and a high frequency amplifier, and a rectangular signal (frequency f ₀ ) synchronized with the high frequency signal is generated. Then, in synchronization with the high-frequency signal f ₀ is Droplet Sn is a high temperature plasma raw material is produced. Here, the stable condition of droplet formation is 3 <λ / d <8 (droplet interval λ, nozzle opening diameter d), droplet diameter D to 2d at stable formation, droplet interval λ to 4d, droplet speed v = f ₀ × λ, and time τ = L / v until the droplet reaches the discharge portion. Next, using a frequency divider a (frequency division ratio 1 / A), a synchronization signal (f ₀ / A) of about 10 kHz is generated. Next, a trigger signal (f _laser = f ₀ / A) is input to the laser device 3 through the delay device a, and a laser pulse is generated after a delay time Δt _laser . Here, the delay time of the delay device a is set so that the laser pulse can be focused and applied to the droplets that have reached the discharge part. Next, when the laser beam is condensed and irradiated onto the droplet, target gas (Sn vapor) is supplied to the discharge part by evaporation of Sn. Next, a trigger signal (frequency f _Discharge = f ₀ / A) is input to the high voltage charging power supply via the delay device b, and a high voltage pulse is applied between the rotating electrodes 6 and 9 after the delay time Δt _Discharge. To do. Here, the target gas conditions (density and size) change over time according to the expansion process. Delay device b so that a high voltage pulse is applied and discharge is performed when a target gas condition that provides optimum plasma conditions (ion density, electron temperature) for emission of extreme ultraviolet light (EUV, 13.5 nm) is reached. Set the delay time.

On the other hand, the rotary electrodes 6 and 9 are driven by a stepping motor (α [rad / pulse]) and a gear box (gear ratio m). Here, the rotational speed is ω = mω ₀ = mαf ₀ / 2π = mαf _laser A / 2π, and the relationship between the number N of protrusions 7 and 10 and the laser irradiation frequency f _laser is f _laser = Nω, protrusions 7 and 10 Pitch a satisfies the relationship of a = 2πR / N = 2πRω / f _laser = RαAm, and the interelectrode gap δ satisfies the relationship of δ <a in order to improve the stability of the discharge position, and Sn droplets The rotation phase difference is adjusted so that the laser pulse, the high voltage pulse, and the rotating electrode protrusion are synchronized. Next, a low repetition synchronization signal (f ₀ / (A × B)) is generated from the synchronization signal (f ₀ / A) by using the frequency divider b (frequency division ratio 1 / B), and the delay signal c is passed through the delay device c. Then, the synchronized CCD camera and the backlight are driven to take a synchronized image. Here, when the CCD camera is NTSC standard, the frequency division ratio is set so as to satisfy f ₀ /(A×B)=59.94 Hz, and the exposure time of the CCD camera or the light emission time of the backlight is about several μs or less. By doing so, a stationary (instantaneous) image of a high-speed moving object can be obtained.

It is a top view which shows the schematic structure of the extreme ultraviolet light source device which concerns on 1st Embodiment, and the front view which shows the structure of the principal part of an extreme ultraviolet light source device. In order to explain in detail the main part of the extreme ultraviolet light source device shown in FIG. 1, the plan view of the rotating electrode as viewed from above (raw material supply side), and the main part of the extreme ultraviolet light source device shown in FIG. It is a front view which looks at a rotating electrode from the front (light emission side) in order to explain in detail. 2 is an enlarged view of the discharge region 18 in which the rotating electrode 6 having the protrusion 7 and the rotating electrode 9 having the protrusion 10 are opposed to each other, and the rotating electrode not having the protrusion according to the related art and the rotating electrode are opposed to each other. It is an enlarged view of a discharge region. It is a top view which shows schematic structure of the extreme ultraviolet light source device which concerns on 2nd Embodiment, and a front view which shows the structure of the principal part of an extreme ultraviolet light source device. It is a top view which shows schematic structure of the extreme ultraviolet light source device which concerns on 3rd Embodiment, and a front view which shows the structure of the principal part of an extreme ultraviolet light source device. It is the top view and sectional drawing which looked at the disk shaped rotating electrode from the top. It is a top view which shows schematic structure of the extreme ultraviolet light source device which concerns on 4th Embodiment, and a front view which shows the structure of the principal part of an extreme ultraviolet light source device. It is a figure which shows a line of electric force in case a processus | protrusion is provided only in one rotation electrode among a pair of rotation electrodes. It is a figure which shows the control system in the extreme ultraviolet light source device which concerns on 1st Embodiment. It is a figure which shows the time chart of the control system shown in FIG. It is sectional drawing which shows the structure of the EUV light source device shown by FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum vessel 2 Vacuum vessel 3 Laser apparatus 4 Laser beam 5 Laser incident window 6 Rotating electrode 7 Protrusion 8 Rotating shaft 9 Rotating electrode 10 Protruding 11 Rotating shaft 12 Droplet target 13 Foil trap 14 EUV collector mirror 15 EUV light emitting window 16 Gas exhaust unit 17 Pulse power supply 18 Discharge area 19 Droplet supply device 20 Target collection cylinders 21 and 22 Motor 23 Metal bus 24 Rotating electrode 25 Protrusion 26 Rotating electrode 27 Protrusion

Claims (7)

A container, a raw material supply means for supplying a liquid or solid raw material for emitting extreme ultraviolet light into the container, an energy beam irradiation means for irradiating the raw material with an energy beam to vaporize the raw material, and the vaporization A pair of discharge electrodes spaced apart from each other by a predetermined distance for heating and exciting the raw material in the container by discharge to generate high-temperature plasma, and pulse power supply means for supplying pulse power between the discharge electrodes A condensing optical means for condensing the extreme ultraviolet light emitted from the high-temperature plasma generated by the discharge between the discharge electrodes, and an extreme ultraviolet light extraction section for extracting the condensed extreme ultraviolet light In the ultraviolet light source device,
The pair of discharge electrodes are disk-shaped discharge electrodes that are rotated by a rotation mechanism connected thereto, and a plurality of protrusions are formed at positions facing the other discharge electrode at the periphery of at least one disk-shaped discharge electrode. An extreme ultraviolet light source device.   2. The extreme ultraviolet light source device according to claim 1, wherein the pair of disc-shaped discharge electrodes are arranged on substantially the same plane.   The extreme ultraviolet light source device according to claim 1, wherein the pair of disk-shaped discharge electrodes are arranged in parallel on the same axis.   The extreme ultraviolet light source device according to any one of claims 1 to 3, wherein the raw material supply means drops the raw material in the vicinity of the discharge electrode.   The extreme ultraviolet light source device according to any one of claims 1 to 3, wherein the raw material supply means applies the raw material to the surface of the discharge electrode.   6. The extreme ultraviolet light source device according to claim 5, wherein the energy beam irradiating means irradiates the tip of the protrusion with an energy beam.   The interval between the protrusions formed on the peripheral edge of the discharge electrode is the closest distance between the discharge electrodes not formed with the protrusions facing the protrusions, or between the protrusions formed on the discharge electrodes facing the protrusions. The extreme ultraviolet light source device according to any one of claims 1 to 6, wherein is wider than the closest interval.

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