JP2008311465A - Euv light source, euv exposure device, and manufacturing method of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means of efficiently cooling an electrode in a rotary electrode type DPP light source. <P>SOLUTION: An EUV light source has an electrode portion, an electrode drive portion, and an electrode cooling portion. The electrode portion makes a target material into plasma by a discharge between a pair of electrodes to emit EUV light from the generated plasma. The electrode drive portion rotates the electrode portion. The electrode cooling portion cools the electrode portion in a non-contact state. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an EUV light source used in an EUV exposure apparatus and its peripheral technology.

  In recent years, with the miniaturization of semiconductor integrated circuits, there has been an EUV exposure apparatus using EUV (Extreme Ultraviolet) light having a wavelength of about 5 to 50 nm in order to improve the resolving power of an optical system limited by the diffraction limit of light. Proposed. In such an EUV exposure apparatus, in order to realize a high throughput, an EUV light source capable of supplying EUV light at a high output is desired.

  As one of the above EUV light sources, a discharge plasma (DPP) light source is known which applies voltage between electrodes to make a target material into plasma and emits EUV light from the plasma. In general, the output of EUV light from a DPP light source increases in proportion to the input power, but when the input power increases, the electrode melts due to overheating.

Therefore, in recent years, a rotating electrode type DPP light source has been proposed. In this rotating electrode type DPP light source, the portions used for discharge are dispersed by the rotation of the electrodes, so that the thermal load is reduced and the input power can be increased more easily than the conventional structure. Non-Patent Document 1 discloses an example of a rotating electrode type DPP light source.
V. Borisov, "Development of EUV source with tin fuel and rotating disk electode", 2006 EUVL Symposium, Oct. 16, 2006

  By the way, in the rotating electrode type DPP light source, the electrode rotates at a high speed. For this reason, when a liquid cooling method, which is a general electrode cooling means in a rotating electrode type DPP light source, is adopted, it is very difficult to shield the refrigerant between the rotating part and the non-rotating part. Problems such as liquid leakage of the refrigerant are likely to occur. Accordingly, there is still a demand for the development of an electrode cooling means suitable for a rotating electrode type DPP light source.

  The present invention is to solve the above-mentioned problems of the prior art. An object of the present invention is to provide means for efficiently cooling an electrode in a rotating electrode type DPP light source.

  An EUV light source according to an aspect of the present invention includes an electrode unit, an electrode driving unit, and an electrode cooling unit. The electrode unit converts the target material into plasma by discharge between the pair of electrodes, and emits EUV light from the generated plasma. The electrode driving unit rotates the electrode unit. The electrode cooling unit cools the electrode unit in a non-contact manner.

  Further, as another embodiment of the present invention, an EUV exposure apparatus provided with the above EUV light source and a semiconductor device manufacturing method using the EUV exposure apparatus are also included in the technical scope of the present invention.

  In the present invention, the rotating electrode portion is cooled in a non-contact manner by the electrode cooling portion, and the electrode is efficiently cooled.

(Description of the first embodiment)
FIG. 1 is a schematic diagram showing the configuration of the EUV light source unit of the first embodiment. The EUV light source unit 11 includes a vacuum chamber 12, a turbo molecular pump 13, an electrode unit 14, a power source 15, an electrode driving unit 16, a laser light source 17, a control unit 18, a condensing optical system 19, and 2 Two radiant temperature control members 20, 21. The power supply 15, the electrode driving unit 16, and the laser light source 17 are connected to the control unit 18, respectively.

  Here, inside the vacuum chamber 12, the electrode part 14, the condensing optical system 19, and the radiation temperature control members 20 and 21 are accommodated. Further, the vacuum chamber 12 is formed with a laser introduction window 12a for introducing laser light from the laser light source 17 and an EUV light emission window for guiding the EUV light to the illumination optical system (in FIG. 1, the illumination optical system and the EUV). The illustration of the light exit window is omitted). During the operation of the EUV light source unit 11, the inside of the vacuum chamber 12 is evacuated by the turbo molecular pump 13 and maintained in a vacuum.

  The electrode unit 14 converts the target material into plasma by discharge between the electrodes, and emits EUV light from the generated plasma. The electrode portion 14 has a pair of electrode plates 22 and 23, an insulating portion 24, and a rotating shaft 25. Each of the electrode plates 22 and 23 is connected to the power source 15 to constitute an anode and a cathode. The overall shape of each of the electrode plates 22 and 23 is substantially the same disk shape. In the first embodiment, molybdenum (Mo), which is a refractory metal, is used as the material of the electrode plates 22 and 23, and the diameter of the electrode plates 22 and 23 is set to 1 m.

  In addition, heat pipes 26 are incorporated in the electrode plates 22 and 23 in order to increase the efficiency of heat conduction at the peripheral and central portions of the electrode plates. As the heat pipe 26, for example, a circular flat plate heat pipe is used. Or you may arrange | position several tubular heat pipes radially on the basis of the center of an electrode plate. As these heat pipes 26, those that can be used in an environment of about 1000K are selected.

  The pair of electrode plates 22 and 23 are arranged in parallel with the insulating portion 24 therebetween. A rotating shaft 25 is connected to the center of one electrode plate 22 located on the upper side in the drawing. That is, in the assembled state of the electrode part 14, the pair of electrode plates 22 and 23 and the insulating part 24 are cantilevered by the rotating shaft 25.

  Furthermore, the target material 27 is supplied to the outer edge portion of the other electrode plate 23 located on the lower side in the drawing. As the target material 27 in the first embodiment, a compound containing tin (Sn) is selected in order to generate EUV light having a wavelength of about 13.5 nm suitable for EUV lithography. Here, the target material 27 is supplied onto the electrode plate 23 by a target supply mechanism that injects a molten target material with a nozzle (illustration of the target supply mechanism is omitted in FIG. 1). A solid target material 27 may be previously annularly arranged on the outer periphery of the electrode plate 23.

  Further, ceramic coatings 22a and 23a are respectively formed on the upper surface side of one electrode plate 22 and the lower surface side of the other electrode plate 23 in order to increase the emissivity. As an example, the ceramic coatings 22a and 23a of each electrode plate are formed by plasma spraying alumina on the surface of the electrode plate.

  The power supply 15 supplies a pulse voltage to the electrode plates 22 and 23 of the electrode unit 14. Moreover, the electrode drive part 16 is connected with the rotating shaft 25 of the electrode part 14, and rotates the electrode part 14 with a motor (not shown).

  Laser light from the laser light source 17 enters the vacuum chamber 12 from the laser introduction window 12 a via the mirror 28 and the condenser lens 29, and irradiates the target material 27 at the position of the light emitting point of the electrode portion 14. Laser light is used to trigger discharge. For this reason, the input energy by the laser light source 17 is set to be negligible compared to the input energy by the power source 15.

  The control unit 18 comprehensively controls the power supply 15, the electrode driving unit 16, and the laser light source 17. Specifically, the control unit 18 operates the electrode driving unit 16 to rotate the electrode unit 14, and controls the application of a pulse voltage by the power source 15 and the irradiation of the laser beam by the laser light source 17 in synchronization. The target material 27 between the plates is turned into plasma.

  The condensing optical system 19 is a Schwarzschild optical system composed of two concentric spherical reflecting surfaces, and condenses EUV light generated at the electrode unit 14 and guides it to the illumination optical system. Each reflecting surface of the condensing optical system 19 is coated with a Mo / Si multilayer film in order to increase the reflectance with respect to EUV light having a wavelength near 13 nm. It is also possible to use a Wolter type optical system for the condensing optical system 19.

  The two radiation temperature adjusting members 20 and 21 are each formed of a circular metal flat plate having the same diameter as the electrode plates 22 and 23. These radiation temperature control members 20 and 21 are arranged above and below with a pair of electrode plates 22 and 23 therebetween. One radiation temperature adjusting member 20 is disposed to face the upper surface of one electrode plate 22 with a slight gap. The other radiation temperature adjusting member 21 is disposed to face the lower surface of the other electrode plate 23 with a slight gap. In addition, in order to avoid interference with the rotating shaft 25, an opening for passing the rotating shaft 25 is formed in the center of the one radiation temperature adjusting member 20.

  Here, copper (Cu) is used as the material of the radiation temperature adjusting members 20 and 21. Moreover, in order to raise a radiation rate, it is a ceramic film | membrane in the opposing surface (the lower surface of one radiation temperature control member 20 and the upper surface of the other radiation temperature control member 21) in each radiation temperature control member 20,21. 20a and 21a are formed. These ceramic coatings 20a and 21a are also formed by plasma spraying alumina as in the case of the electrode plate.

  Furthermore, a heat exchanger including a liquid cooling pipe is connected to each of the radiation temperature adjusting members 20 and 21. Therefore, the radiation temperature adjusting members 20 and 21 are cooled to a predetermined temperature (illustration of the heat exchanger is omitted).

  Next, the operation of the EUV light source unit 11 of the first embodiment will be described. During the operation of the EUV light source unit 11, the electrode driving unit 16 rotates the electrode unit 14, and the power source 15 applies a pulse voltage to the electrode unit 14. Laser light is emitted from the laser light source 17 toward the electrode unit 14. In the EUV light source unit 11 of the first embodiment, 50 kW of electric power is applied to continuously generate 1000 W of EUV light at the light emitting point and 200 W at the intermediate focusing point (IF).

  When the target material 27 on the other electrode plate 23 evaporates by laser ablation, a current flow path is generated and discharge is started between the electrode plates 22 and 23. By this discharge, the target material 27 is turned into plasma, and EUV light is emitted from this plasma. The EUV light is guided to the illumination optical system of the exposure apparatus through the condensing optical system 19 and the EUV light exit window. In addition, the part used for discharge in the electrode part 14 changes with rotation.

  In addition, the electrode plates 22 and 23 of the electrode portion 14 are radiatively cooled in a non-contact manner by the two radiation temperature adjusting members 20 and 21 arranged to face each other. Therefore, in the first embodiment, the rotating electrode plate can be efficiently cooled, and the output of EUV light can be improved by increasing the input power to the electrode unit 14.

  Here, radiation cooling in the radiation temperature adjusting member in the first embodiment will be described in detail. In the current DPP light source, the energy conversion efficiency to EUV light with respect to the input power to the electrode is generally about 2%. Further, the transmission efficiency of the optical system when the EUV light generated at the light emitting point of the DPP light source is guided to the IF by the condensing optical system is about 20%. The light source of the EUV exposure apparatus is required to output 100 W to 200 W EUV light at the IF. In the DPP light source, the input power required to obtain the output of the EUV light is 25 kW to 50 kW. Since most of the input power to the DPP light source is heat, the amount of heat generated by the electrode in the DPP light source can be regarded as 25 kW to 50 kW.

  On the other hand, the amount of heat transfer due to radiation from the electrode plate of the electrode portion 14 to the radiation temperature adjusting member is obtained in the following manner. In general, the amount of heat Q that is moved by radiation between two opposing flat plates can be obtained by the following equation (1).

In the above formula (1), σ represents a Stefan Boltzmann constant (5.67 × 10 ⁻⁸ [W / m ² K ⁴ ]). T _i denotes the absolute temperature [K] of the member i. ε _i indicates the emissivity of the member i. A shows the area [m ² ] of the flat plate. F _ij indicates a shape factor between the members i and j. The member 1 corresponds to an electrode plate, and the member 2 corresponds to a radiation temperature adjusting member.

Here, if the material of the flat plate surface is appropriately selected, the emissivity can be made close to 1. Therefore, when the emissivity is 1 in the above formula (1), the following formula (2) can be obtained.
Q = AF ₁₂ σ (T ₁ ⁴ −T ₂ ⁴ ) (2)
Further, when the form factor in the case of the opposing flat plate having a narrow gap is 1, the following formula (3) can be obtained from the above formula (2).
Q = Aσ (T ₁ ⁴ −T ₂ ⁴ ) (3)
Furthermore, the temperature T _{1 of the} electrode plate is sufficiently higher than the temperature T ₂ of the radiation temperature adjusting member. Therefore, the above equation (3) can be approximated by the following equation (4). That is, the amount of heat transferred by radiation is proportional to the area of the flat plate and proportional to the fourth power of the temperature of the electrode plate.
Q = AσT ₁ ⁴ (4)
As an example, the area of the electrode plate and the radiation temperature adjusting member is 1 m ^2, and the temperature of the electrode plate is 1000 K (727 ° C.). In this case, the heat amount of Q = 56.7 kW can be removed from the electrode plate by the radiation temperature adjusting member. The amount of heat transfer due to this radiation exceeds the amount of heat generated on the electrode side (25 kW to 50 kW). Therefore, it turns out that an electrode plate can fully be cooled by arrange | positioning a radiation temperature control member.

In particular, in the configuration of the first embodiment, the opposing area of the electrode plate and the radiation temperature adjusting member is about 1.5 m ² when the upper and lower sides are combined. Therefore, when the temperature of the electrode plate is 1000 K, 85 kW of heat is removed from the electrode plate by the two radiation temperature adjusting members 20 and 21.

  In the first embodiment, since the ceramic coating (20a, 21a, 22a, 23a) is formed on each radiation surface of the radiation temperature adjusting member and the electrode plate, the radiation efficiency is improved and the electrode plate by radiation is improved. Is more efficiently cooled.

  Further, as described above, heat transfer by radiation is proportional to the fourth power of the temperature, but is also proportional to the area. When the temperature of only a part of the radiation surface of the electrode plate rises, the radiation plate also receives heat and the temperature rises. When the temperature of the radiation plate rises, radiation efficiency, that is, heat transfer becomes worse, so that the radiation plate is cooled by a cooling means such as a refrigerant in order to reduce the temperature rise. However, when only a part of the radiation plate becomes high temperature, the cooling cannot be sufficiently performed, and the radiation efficiency may be lowered. In particular, in the electrode plate, the peripheral portion used for generating plasma is heated more than the central portion, and the radiation efficiency of the peripheral portion may decrease with time. In the first embodiment, since the heat pipe 26 is built in each electrode plate, heat transfer from the peripheral portion of the electrode plate to the central portion is performed quickly, and heat transfer by radiation is performed on the entire radiation surface of the electrode plate. It becomes possible to carry out almost uniformly, and it can prevent that a radiation efficiency falls with time.

(Description of Second Embodiment)
FIG. 2 is a schematic diagram showing the configuration of the EUV light source unit 11a of the second embodiment. Note that, in the following description of the embodiment, the same reference numerals are given to portions common to the configuration of the above-described embodiment, and duplicated description is omitted.

  In the EUV light source unit 11a of the second embodiment, the liquid supply unit 30 is disposed above and below the pair of electrode plates 22 and 23 with a space therebetween. Each liquid supply unit 30 has a nozzle 30a that ejects water droplets to the electrode plate, and ejection of the water droplets is controlled by a piezoelectric vibrator. The liquid supply unit 30 is connected to the control unit 18 (illustration of signal lines between the control unit 18 and the liquid supply unit 30 is omitted).

  During the operation of the EUV light source unit 11 a, the liquid supply unit 30 ejects water droplets to the electrode plates 22 and 23. Since the temperature of the electrode plate is sufficiently higher than the boiling point of water (100 ° C.), the water droplets in contact with the electrode plate are instantly evaporated. The electrode plate is cooled by the heat of vaporization taken away by the evaporation of water. Here, since the heat of vaporization of water is 2.44 kJ / g, heat of 24.4 kW to 44.8 kW can be removed from the electrode plate by supplying 10 g to 20 g of water per second. Therefore, the rotating electrode plate can be sufficiently cooled in a non-contact manner also by the configuration of the second embodiment.

  Here, the amount of water droplets supplied from the liquid supply unit 30 and the size of the water droplets are set so that all the water droplets can be evaporated when they come into contact with the electrode plate. In the second embodiment, since a large amount of high-temperature water vapor is generated in the vacuum chamber 12, it is necessary to increase the exhaust capacity of the turbo molecular pump 13. Instead of the turbo molecular pump 13, a cryopump having a high pumping speed with respect to water is used, or the vicinity of the electrode section 14 is pumped by a pump with a high pumping speed at a low vacuum (several Pa) such as a scroll pump and maintained at a high vacuum Differential pumping may be performed with the condensing optical system 19 to be performed.

  In addition, there is a certain time delay from the application of the pulse voltage to the electrode unit 14 until the heat is transferred to the back side of the electrode plate (the surface on which the water droplet collides). Therefore, in consideration of the above time delay, the water droplet ejection timing of the liquid supply unit 30 is slightly delayed with respect to the pulse voltage timing so that the water droplet collides after heat is transferred to the back side of the electrode plate. It is preferable to use timing.

  FIG. 3 is a top view illustrating an example of a positional relationship between the electrode plate 22 and the liquid supply unit 30. The liquid supply unit 30 is disposed at a position shifted in the direction of the rotation destination from the EUV light emission point in the electrode unit 14. In this case, during operation of the EUV light source unit 11a, water droplets are supplied to the heated portion immediately after discharge on the electrode plate due to the rotation of the electrode unit. Therefore, the rotating electrode plate can be cooled more efficiently by the heat of vaporization of the water droplets. Note that the relative relationship between the position of the light emitting point and the position of the liquid supply unit 30 is appropriately adjusted in consideration of the rotational speed of the electrode unit 14 and heat transfer to the back side of the electrode plate described above.

(Description of the third embodiment)
FIG. 4 is a schematic diagram showing the configuration of the EUV light source unit 11b of the third embodiment. In the third embodiment, the radiation temperature adjusting members 20 and 21 and the liquid supply unit 30 are arranged above and below the pair of electrode plates 22 and 23, respectively.

  FIG. 5 is a top view illustrating an arrangement example of the radiation temperature adjusting member 20 and the liquid supply unit 30 in the third embodiment. In the example of FIG. 5, the annular radiation temperature adjusting member 20 is disposed in the periphery of the electrode plate 22 that becomes high temperature due to discharge, and the liquid supply unit 30 is disposed near the center of the electrode plate 22. In the third embodiment, a plurality of liquid supply units 30 may be arranged for one electrode plate (illustration is omitted in this case).

  Also according to the configuration of the third embodiment, the rotating electrode plate can be efficiently cooled in a non-contact manner as in the above embodiment.

  In this embodiment, the periphery of the electrode plate, which tends to have a relatively high temperature, is cooled by radiation. As described above, since the radiation efficiency is proportional to the fourth power of the temperature, it can be cooled with relatively high efficiency. The central portion, which is a relatively low temperature region, is cooled with water. Since water evaporates at 100 ° C. or lower because it is in a vacuum, the electrode can be cooled with heat of vaporization. In this embodiment, it is possible to improve the overall cooling efficiency by using the good points of the two cooling means.

(Description of EUV exposure apparatus)
Embodiments of an EUV exposure apparatus according to the present invention will be described below. FIG. 6 is a schematic diagram showing the configuration of the EUV exposure apparatus. This EUV exposure apparatus has an EUV light source unit 40 (11, 11a, 11b) selected from any of the first and third embodiments described above, an exposure unit 41, and a controller 42. .

  The exposure unit 41 includes an illumination optical system 43, a mask stage 45 that suspends and supports a reflective mask 44, a projection optical system 46, a wafer stage 48 on which a wafer 47 is placed, and a vacuum chamber 49 that houses these. And have.

  Here, the illumination optical system 43 includes a fly-eye optical system reflecting mirror, etc., and shapes the EUV light from the EUV light source unit 40 and guides it to the reflective mask 44. A reflective film made of a multilayer film is formed on the reflective surface of the reflective mask 44. A mask pattern corresponding to the pattern to be transferred to the wafer 47 is formed on the reflective film. The projection optical system 46 includes a plurality of reflecting mirrors, and projects the EUV light reflected by the reflective mask 44 onto the wafer 47 after being reduced to a predetermined reduction magnification (for example, ¼). In addition, since EUV light has low permeability to the atmosphere, any optical path through which EUV light passes is kept in a vacuum.

  During the exposure operation, the EUV light from the EUV light source unit 40 enters the reflective mask 44 via the illumination optical system 43. Then, the reflected light from the reflective mask 44 is projected onto the wafer 47 via the projection optical system 46. As a result, the miniaturized mask pattern forms an image on the wafer 47 coated with the resist. Then, the mask stage 45 and the wafer stage 48 move the reflective mask 44 and the wafer 47 with respect to the projection optical system 46 at a predetermined speed ratio according to the reduction magnification described above. As a result, the entire circuit pattern of the reflective mask 44 is transferred to each of the plurality of shot areas on the wafer 47 by the step-and-scan method. The operations of the EUV light source unit 40, the mask stage 45, and the wafer stage 48 are all controlled by the controller 42.

  The exposure apparatus of the present embodiment can efficiently cool the electrodes of the light source unit, so that the light source can be used for a long time, and the downtime can be relatively shortened. is there.

(Description of semiconductor device manufacturing method)
Embodiments of a semiconductor device manufacturing method according to the present invention will be described below. FIG. 7 is a flowchart showing an example of the semiconductor device manufacturing method of the present invention. The manufacturing process in the example of FIG. 7 includes the following main processes.
(1) Wafer manufacturing process for manufacturing a wafer (or wafer preparation process for preparing a wafer)
(2) Mask manufacturing process for manufacturing a mask used for exposure (or mask preparation process for preparing a mask)
(3) Wafer processing step for performing necessary processing on the wafer (4) Chip assembly step for cutting out chips formed on the wafer one by one and making them operable (5) Chip inspection step for inspecting the completed chips Each process is further composed of several sub-processes.

Among these main processes, the main process that has a decisive influence on the performance of the semiconductor device is the wafer processing process. In this step, designed circuit patterns are sequentially stacked on a wafer to form a large number of chips that operate as memories and MPUs. This wafer processing step includes the following steps.
(1) A thin film forming process for forming a dielectric thin film to be an insulating layer, a wiring portion, or a metal thin film for forming an electrode portion (using CVD, sputtering, etc.)
(2) Oxidation process for oxidizing the thin film layer and wafer substrate (3) Lithography process for forming a resist pattern using a mask (reticle) to selectively process the thin film layer and wafer substrate, etc. (4) Resist Etching process that processes thin film layers and substrates according to patterns (eg, using dry etching technology)
(5) Ion / impurity implantation / diffusion process (6) Resist stripping process (7) Inspection process for inspecting the processed wafer Further, the wafer processing process is repeated for the required number of layers, and the semiconductor operates as designed. Manufacture devices.

  In the semiconductor device manufacturing method of the present embodiment, the EUV exposure apparatus according to the embodiment of the present invention is used in the lithography process. Therefore, in the semiconductor device manufacturing method of the present embodiment, the total device yield can be increased with a short downtime.

(Supplementary items of the embodiment)
(1) In the said embodiment, materials, such as a radiation temperature control member, can be changed suitably. As a material of the radiation temperature adjusting member, for example, a metal having high thermal conductivity such as aluminum, tungsten, molybdenum, zinc, or an alloy containing these as components may be used. Further, the ceramic coating of the electrode plate and the radiation temperature adjusting member may be formed of titanium oxide, silica, aluminum nitride, tungsten carbide, or the like. Furthermore, the above ceramic coating may be formed by a method such as sputtering, vapor deposition, or wrinkling.

  (2) In the above embodiment, an example of an exposure apparatus that manufactures a semiconductor device by exposing a circuit pattern on a wafer has been described. However, the exposure apparatus of the present invention is not limited to the above. For example, the present invention can naturally be applied to an exposure apparatus for forming a circuit pattern (pixels, transparent electrodes, thin film transistors, etc.) on a glass substrate used for a liquid crystal type or plasma type flat display device, and a method for manufacturing the device. .

  The present invention can be implemented in various other forms without departing from the spirit or the main features thereof. Therefore, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The present invention is defined by the claims, and the present invention is not limited to the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

Schematic diagram showing the configuration of the EUV light source unit of the first embodiment Schematic diagram showing the configuration of the EUV light source unit of the second embodiment Top view showing an example of the positional relationship between the electrode plate and the liquid supply unit Schematic diagram showing the configuration of the EUV light source unit of the third embodiment Top view showing an arrangement example of the radiation temperature adjusting member and the liquid supply unit Schematic diagram showing the configuration of the EUV exposure apparatus of the present invention The flowchart which shows an example of the semiconductor device manufacturing method of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 11a, 11b, 40 ... EUV light source unit, 14 ... Electrode part, 16 ... Electrode drive part, 20, 21 ... Radiation temperature control member, 22, 23 ... Electrode plate, 20a, 21a, 22a, 23a ... Ceramic film, 26 ... Heat pipe, 27 ... Target material, 30 ... Liquid supply unit, 43 ... Illumination optical system, 44 ... Reflective mask, 46 ... Projection optical system, 47 ... Wafer

Claims (7)

An electrode part that converts the target material into plasma by discharge between a pair of electrodes and emits EUV light from the generated plasma;
An electrode driving unit for rotating the electrode unit;
An EUV light source comprising: an electrode cooling unit that cools the electrode unit in a non-contact manner. The EUV light source according to claim 1,
The electrode cooling unit is an EUV light source having a radiation temperature adjusting member disposed to face at least one of an anode and a cathode of the electrode unit. The EUV light source according to claim 2,
An EUV light source in which a ceramic coating is formed on at least one radiation surface of the electrode portion and the radiation temperature adjusting member. The EUV light source according to claim 2,
An EUV light source in which a heat pipe is built in the electrode part. The EUV light source according to any one of claims 1 to 4,
The electrode cooling unit is an EUV light source having a liquid supply unit that ejects liquid to at least one of an anode and a cathode of the electrode unit. The EUV light source according to any one of claims 1 to 5,
An illumination optical system for irradiating the mask with EUV light from the EUV light source;
An EUV exposure apparatus comprising: a projection optical system that exposes and transfers a pattern formed on the mask to a sensitive substrate.   A method for manufacturing a semiconductor device, comprising: a step of exposing and transferring a pattern formed on a mask to a sensitive substrate using the EUV exposure apparatus according to claim 6.

Images