JP2007027237A - Exposure apparatus, light source device, and device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an economic exposure apparatus which demonstrates a superior exposure properties by preventing a decline in throughput and resolution, by preventing deterioration of reflection and the ununiformity in illuminance of an optical element. <P>SOLUTION: The exposure apparatus includes an illumination optical system which illuminates pattern by exposure light from a light source which generates exposure light using a plasma, and transfers the pattern onto an exposed material. The exposure apparatus includes a measuring device for measuring the quantity of contaminant which flows from the light source to the illumination optical system, and/or for detecting the kind of the contaminant; and a decision portion which decides the performance of the light source, based on the measurement results and/or the detection results of the measuring device. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention generally relates to an exposure apparatus, and more particularly, a semiconductor chip such as an IC or LSI, a display element such as a liquid crystal panel, a detection element such as a magnetic head, an imaging element such as a CCD, or a micro device used in micromechanics. The present invention relates to a light source device of an exposure apparatus used for manufacturing a pattern. The present invention is suitable for, for example, an exposure apparatus that uses extreme ultraviolet (EUV) light as an exposure light source.

  A projection exposure apparatus that exposes a circuit pattern drawn on a reticle (mask) onto a wafer or the like with a projection optical system has been used in the past, and in recent years, an exposure apparatus that has high resolution and is economical is increasingly required. Yes.

  The minimum dimension (resolution) that can be transferred by the reduction projection exposure apparatus is proportional to the wavelength of light used for exposure and inversely proportional to the numerical aperture (NA) of the projection optical system. Therefore, the shorter the wavelength, the better the resolution. Therefore, in order to efficiently transfer a very fine circuit pattern of 0.1 μm or less, a reduction projection exposure apparatus using extreme ultraviolet (EUV) light having a wavelength shorter than that of ultraviolet light and having a wavelength of about 10 nm to 15 nm ( Hereinafter, it is referred to as “EUV exposure apparatus”).

An EUV exposure apparatus uses a laser plasma light source that generates EUV light by irradiating a target material with laser light as a light source, or generates plasma by flowing a gas through an electrode and discharging it to generate EUV light. A discharge-type plasma light source that generates the light is typically used (see, for example, Patent Documents 1 and 2). EUV light from the plasma is condensed at a condensing point by a condensing mirror, diverges from the condensing point, and the subsequent illumination optics through an opening formed between the light source unit and the illumination optical system. Incident into the system.
JP 2002-174700 A Japanese Patent Application Laid-Open No. 2003-077698

  However, gas containing contaminants generated in the light source chamber flows into the illumination optical system from an opening formed between the light source unit and the illumination optical system. As a result, contaminants adhere to the surface of the optical element of the illumination optical system and absorb light, thereby reducing the reflectance of the optical element. Furthermore, the illuminance may be non-uniform. As a result, throughput and resolution are reduced.

  In this case, in order to prevent the inflow of contaminants, it is preferable to arrange a window material serving as a vacuum partition wall in an opening (connection portion) between the chamber of the light source and the chamber of the illumination optical system. However, there is no material that can transmit EUV light, or a material that can sufficiently withstand the heat load of EUV light having the power required for projection exposure. Therefore, it is difficult to prevent the inflow of contaminants into the illumination optical system. Therefore, as another method for reducing the inflowing pollutants, it is conceivable to reduce the amount of pollutants generated from the light source unit. Contaminants are often generated due to deterioration of members used in the light source unit, and can be reduced by, for example, replacement of the deteriorated members. However, since there are many members that can generate a large amount of pollutants, it is not appropriate to judge the replacement of the members based on the amount of pollutants in terms of economy. Therefore, in order to reduce pollutants, it is increasingly important to determine the deterioration of the light source member.

  Accordingly, the present invention provides an economical exposure apparatus that prevents the reduction in throughput and resolution by preventing the reflectance of the optical element from decreasing and the illuminance from becoming nonuniform, and exhibiting excellent exposure performance. For illustrative purposes.

  An exposure apparatus according to an aspect of the present invention is an exposure apparatus that includes an illumination optical system that illuminates a pattern with the exposure light from a light source unit that generates exposure light by plasma, and exposes the pattern onto an object to be exposed. And measuring the amount of contaminants flowing into the illumination optical system from the light source unit and / or detecting the type of contaminants, and based on the measurement results and / or detection results of the measurement devices, And a determination unit that determines the performance of the light source unit.

  An exposure apparatus according to another aspect of the present invention includes an illumination optical system that illuminates a pattern using light from a light source unit that emits exposure light by plasma generated in a space surrounded by a light source chamber, An exposure apparatus that exposes a pattern onto an object to be exposed, which measures the amount of contaminants in the light source chamber and / or detects the type of contaminant, and the measurement results and / or detection results of the measurement apparatus And a determination unit that determines the performance of the light source unit.

A light source device according to another aspect of the present invention includes a generation unit that generates light by plasma,
It has a chamber for storing the generating unit, and a measuring device for measuring the amount of contaminants in the chamber and / or detecting the kind of contaminants.

  A device manufacturing apparatus according to another aspect of the present invention includes a step of exposing an object to be exposed using the exposure apparatus described above, and a step of developing the exposed object to be exposed.

  According to the present invention, it is possible to provide an economical exposure apparatus that prevents a decrease in reflection of optical elements and non-uniform illuminance, prevents a decrease in throughput and resolution, and exhibits excellent exposure performance. .

  Hereinafter, an exposure apparatus 1 according to one aspect of the present invention will be described with reference to the accompanying drawings. In addition, in each figure, the same reference number is attached | subjected about the same member and the overlapping description is abbreviate | omitted. FIG. 1 is a schematic sectional view showing the arrangement of an exposure apparatus 1 according to the present invention.

  The exposure apparatus 1 of the present invention is formed on the mask 300 by using, for example, a step-and-scan method or a step-and-repeat method using EUV light (for example, a wavelength of 13.4 nm) as illumination light for exposure. This is a projection exposure apparatus that exposes a circuit pattern onto an object to be exposed 600. Such an exposure apparatus is suitable for a lithography process of sub-micron or quarter micron or less, and in the present embodiment, a step-and-scan type exposure apparatus (also referred to as “scanner”) will be described as an example. Here, the “step and scan method” means that the wafer is continuously scanned (scanned) with respect to the mask to expose the mask pattern onto the wafer, and the wafer is stepped after the exposure of one shot is completed. The exposure method moves to the next exposure area. The “step-and-repeat method” is an exposure method in which the wafer is stepped and moved to the exposure area of the next shot for every batch exposure of the wafer.

  Referring to FIG. 1, an exposure apparatus 1 includes a light source device 100, an illumination optical system 200, a mask stage 400 on which a mask 300 is placed, a projection optical system 500, and a wafer stage on which an object to be exposed 600 is placed. 700, an alignment detection mechanism 800, and a focus position detection mechanism 900. The light source device 100 and the illumination optical system 200 constitute an illumination device, and illuminate the mask 300 with arc-shaped EUV light (for example, 13.4 nm) with respect to the arc-shaped field of the projection optical system 500.

  Further, as shown in FIG. 1, EUV light has a low transmittance to the atmosphere and generates contamination due to a reaction with a residual gas (polymer organic gas) component. Therefore, the chamber VC of the entire optical system is illustrated in FIG. Not evacuated by the evacuation system.

  In the present embodiment, the light source device 100 is a discharge plasma light source. As shown in FIG. 2, the generation unit 110, the debris filter 120, the condensing mirror 130, the differential exhaust chamber 140, the light source chamber 150, and the like. , Measuring device 160, determination unit 170, output device 175, and control unit 180. Here, FIG. 2 is a cross-sectional view showing the configuration of the light source device 100 and the illumination optical system 200 of the exposure apparatus 1.

  The generation unit 110 generates a discharge by, for example, a xenon (Xe) gas supplied from the nozzle 112 and a high voltage applied to the electrode 114, and further, a high density plasma by a pinch action by a self magnetic field of a charged particle flow. PL is generated. EUV light EL is generated from the plasma PL.

  The EUV light EL from the plasma PL passes through a debris filter 120 that removes debris particles, and is reflected by a condensing mirror 130 including two pairs of mirrors having a spheroid surface as a reflecting surface, and is reflected at a condensing point CP. Condensate. As described above, the EUV light EL has a property of being absorbed by gas. In order to prevent such absorption, the generation unit 110, the debris filter 120, and the collecting mirror 130 are exhausted by a vacuum exhaust system (not shown). The light source chamber 150 is arranged inside.

  The EUV light EL condensed at the condensing point CP is introduced into an illumination system chamber 250 in which optical elements constituting the illumination optical system 200 described later are arranged, reflected by the illumination system mirror 210, and then an optical integrator. Then, the light is incident on 220, and the mask 300 is illuminated uniformly through the illumination system mirror 210.

  The illumination system chamber 250 is evacuated by a vacuum exhaust system (not shown) in the same manner as the light source chamber 150 in order to prevent the EUV light from being absorbed by the gas. In addition, although the inside of the light source chamber 150 is exhausted by the vacuum exhaust system, the gas supplied from the nozzle 112 exists. In addition, an aperture 152b is provided at the boundary between the light source chamber 150 and the illumination system chamber 250 to transmit the EUV light EL, and differential exhaust is performed between the light source chamber 150 and the illumination system chamber 250. The smaller the size of the aperture 152b, the smaller the amount of gas flowing from the light source chamber 150 into the illumination system chamber 250. Therefore, the position of the aperture 152b is made to coincide with the position of the condensing point CP. It is preferable to make the height substantially coincide with the size of the condensing point CP. In the differential exhaust between the condensing mirror chamber 154 and the illumination system chamber 250, the aperture 152b having a size almost the same as that of the condensing point CP is used, so that the pressure in the illumination system chamber 250 is increased in the condensing mirror chamber 154. The pressure can be about 1/10 to 1/100 of the pressure. However, in the differential exhaust between the generator chamber 156 and the condenser mirror chamber 154, the aperture 156a is formed larger than the aperture 152b because the debris filter 120 is provided at the boundary. Therefore, the pressure reduction in the differential exhaust of the generator chamber 156 and the condenser mirror chamber 154 is not as significant as the differential exhaust of the condenser mirror chamber 154 and the illumination system chamber 250.

  The differential exhaust chamber 140 is connected to the light source chamber 150 and maintains a pressure different from that of the light source chamber 150. The differential exhaust chamber 140 is formed between the light source chamber 150 and a measuring device 160 described later, and communicates with the aperture 152c. The differential exhaust chamber 140 also maintains a lower pressure than the light source chamber 150 for the measurement device 160. The size of the aperture 152c is smaller than the aperture 152a, and is the same as or smaller than the aperture 152b.

  The measuring device 160 measures the amount of contaminant flowing into the illumination optical system 200 from the light source unit (light source device 100) and / or detects the type of contaminant. Here, the contaminant is preferably all gases other than the Xe gas supplied from the nozzle 112, but if it is a small amount of inert gas (for example, nitrogen, argon, etc.), it should not be treated as a contaminant. It doesn't matter. In addition, the detection of the type of pollutant by the measuring device may mean the detection of the type of pollutant itself by the measuring device, but it is possible to identify the pollutant by an arithmetic device connected to this measuring device. This may mean data acquisition.

  In this case, in this embodiment, the measuring device 160 measures the amount of contaminants in the light source chamber 150 and measures the amount of contaminants flowing into the illumination optical system 200 based on the measurement result. . The measuring device 160 detects the mass spectrum of the gas in the condensing mirror chamber 154, calculates the gas type and its partial pressure in the condensing mirror chamber 154, and transmits the calculation result to the determination unit 170 described later. To do. Further, the measuring device 160 also measures the amount of inflow of contaminants into the illumination optical system 200. The measuring device 160 may measure at predetermined time intervals during the generation of the plasma PL. In this embodiment, a quadrupole mass spectrometer is used as the measuring device 160. Here, the quadrupole mass spectrometer is an apparatus that has four electrodes and measures the type of a substance present in a vacuum and the pressure of a gas. The quadrupole-type mass spectrometer measures not only the pressure in the collector mirror chamber 154 output from a vacuum gauge (not shown) that measures the pressure in the collector mirror chamber 154, but also the gas species in the collector mirror chamber 154 and The partial pressure can be calculated. Further, since the quadrupole mass spectrometer normally requires a certain degree of vacuum, the differential exhaust chamber 140 has a lower pressure than the condensing mirror chamber 154. In this case, when the pressure in the collector mirror chamber 154 is within the operating range of the quadrupole mass spectrometer 140, the quadrupole mass spectrometer 140 may be directly connected to the collector mirror chamber 154.

  In the light source chamber 150, a slight amount of organic gas, for example, hydrocarbon, which causes a pollutant is generated from an organic material used as a part of the constituent member, an inner wall of the light source chamber 150, or the like. This gas flows into the illumination system chamber 250 like the plasma generation gas. When the light source device 100 is operated over a long period of time and the generation unit 110 deteriorates and the generation of gas that causes the pollutant increases, the amount of pollutant attached to the illumination optical system increases. However, in this embodiment, the quadrupole mass spectrometer 140 detects the partial pressure of the gas that causes the pollutant. If this partial pressure is equal to or greater than a predetermined specified amount, the determination unit 170 and It is possible to prevent the contaminant from adhering to the illumination optical system by the measure of the control unit 180.

  In the present embodiment, the measurement device 160 is connected to the condensing mirror chamber 154 via the differential exhaust chamber 140, but may be connected to the generation unit chamber 156. Further, the measuring device 160 may be connected to the illumination system chamber 250. In this case, since the generation of the gas that causes the pollutant is hardly generated in the illumination system chamber 250, the measurement device 160 is substantially within the light source chamber 150. Since this is equivalent to detecting the type and partial pressure of the gas, the same effect can be obtained. In the case of a chamber having, for example, an optical axis adjusting optical system between the light source chamber 150 and the illumination system chamber 250, the measuring device 160 may be connected to the chamber.

  Note that it is not easy to accurately determine the type and partial pressure of a gas from the measured mass spectrum because of specifying the partial pressure from the mass number and the difference in sensitivity to each ion. However, in the present embodiment, the gas types that cause the contaminants present in the light source chamber 150 are limited, so that it is possible to obtain the accuracy necessary for measurement. The measuring device 160 is not limited to a quadrupole mass spectrometer. For example, a magnetic field deflection mass spectrometer may be used as the mass spectrometer. Here, the magnetic field deflection type mass spectrometer is a device that measures the type of a substance existing in a vacuum and the pressure of a gas using a magnetic field.

  The determination unit 170 determines the performance of the light source unit (light source device 100) based on the measurement result of the measurement device 160. That is, the determination unit 170 determines the performance state of the optical device 100 based on the measurement results (contaminant amount, gas type, and partial pressure) from the measurement device 160. The determination method of the determination unit 170 is determined based on a table as defined values recorded in a memory (not shown). For example, if the gas type or partial pressure is equal to or higher than a specified value, the determination result is transmitted to the control unit 180 described later. The determination unit 170 is electrically connected to the measurement device 160 and the control unit 180.

  The output device 175 outputs the determination result of the determination unit 170. Therefore, the output device 175 is electrically connected to the determination unit 170. The output method of the output device 175 can not only display the determination result on the liquid crystal screen but also transmit the determination result to the user by a lamp or sound. The output device 175 can also output a control result from the control unit 180 described later. In this case, the output device 175 is electrically connected to the control unit 180.

  The control unit 180 controls the amount of light generated based on the determination result by the determination unit 170. In this case, the control unit 180 changes the operation parameter of the generation unit 110. As the change of the operation parameter, for example, the light quantity of light is changed, the exhaust capacity of a vacuum exhaust system (not shown) that exhausts the light source chamber 150 is increased, or the capacity of the cooling system that cools the constituent members of the generation unit 110 Is increasing. Accordingly, the control unit 180 causes the partial pressure of the gas that causes the pollutant to be equal to or less than a predetermined specified amount.

  As another method, the control unit 180 stops the exposure, and a gate valve provided between the light source and the illumination optical system in order to block the inflow of the gas causing the contaminant into the illumination optical system. Close. And a signal is displayed by the output device 175, and a user performs failure diagnosis. In this case, when it is determined that the change can be made by changing the operation parameter of the generation unit 110, the control unit 180 performs the exposure after changing the operation parameter described above. As another method, the control unit 180 stops the exposure, causes the output device 175 to display a signal, and causes the user to perform a failure diagnosis. Then, the constituent member of the generation unit 110 that has deteriorated is specified, and exposure is performed after replacement of the constituent member.

  As another method, when exposure is suspended for a long time for maintenance or other reasons, the concentration of substances (contaminants) that cause contamination such as hydrocarbons in the gas supply path increases. Cheap. Therefore, the control unit 180 stops the exposure based on the determination by the determination unit 170 based on the measurement result (gas type and partial pressure) from the measurement device 160. At the same time, the control unit 180 keeps the gas flowing until the partial pressure of the gas that causes the pollutant falls below a predetermined specified amount, or stops the gas supply and exhausts the gas supply path with a vacuum pump. Exhaust gases that cause pollutants. Then, the control unit 180 resumes the exposure when the partial pressure of the gas that causes the pollutant becomes equal to or less than a predetermined specified amount.

  As another method, the amount of contaminants is reduced by reducing the amount of light emitted from the light source unit. In that case, it is inevitable that the throughput is reduced, but such an option is also possible if the throughput may be slightly sacrificed.

  As a result, the exposure apparatus 1 can prevent a reduction in throughput and resolution by preventing a decrease in reflection of optical elements and non-uniform illuminance, and can exhibit excellent exposure performance. In addition, since it is easy to determine the deterioration of the constituent members, unnecessary replacement of the constituent members can be prevented and economically improved.

  The illumination optical system 200 is an optical system that illuminates the mask 300, and includes the illumination system mirror 210, the optical integrator 220, the Schwarzschild reflector, and the like as described above. Further, the illumination optical system 200 may have an opening for limiting the illumination area of the mask 300 to an arc shape at a position conjugate with the mask 300.

  Hereinafter, with reference to FIG. 3, a measurement apparatus 160A according to the second embodiment will be described. The members denoted by the same reference numerals as those in FIG. 2 are the same members as those in the first embodiment, and detailed description thereof is omitted. Here, FIG. 3 is a cross-sectional view showing configurations of the light source device 100A and the illumination optical system 200A.

  The measurement device 160A is connected to the optical device 100A and the illumination optical system 200A, and measures the amount of contaminant flowing into the illumination optical system 200A from the light source unit (light source device 100A) and / or detects the type of contaminant. The measurement device 160A includes a differential pressure gauge 162A and a measurement unit 164A.

  The differential pressure gauge 162A is connected to the condenser mirror chamber 154A and the illumination system chamber 250A, and detects a differential pressure between the pressure in the condenser mirror chamber 154A and the pressure in the illumination system chamber 250A. Based on the detection result, the differential pressure gauge 162A calculates the amount of contaminant flowing into the illumination system chamber 250A from the light source chamber 150A. As the differential pressure gauge 162A, for example, a Baratron type differential pressure gauge is used. The differential pressure gauge 162A is electrically connected to the determination unit 170A and transmits the acquired information to the determination unit 170A.

  The measurement unit 164A measures the amount of contaminant flowing into the illumination optical system 200A from the light source unit (light source device 100A) and / or detects the type of contaminant. In this case, in this embodiment, the measurement unit 164A measures the amount of contaminant in the illumination system chamber 250A, and calculates the amount of contaminant flowing into the illumination optical system 200A based on the measurement result. Yes. Specifically, the measurement unit 164A detects the mass spectrum of the gas in the condensing mirror chamber 154A, calculates the gas type and its partial pressure in the condensing mirror chamber 154A, and calculates the determination unit 170A described later. Communicate the results. The measurement unit 164A also measures the type of contaminant. Further, the measurement unit 164A may measure at predetermined time intervals during the generation of the plasma PL. In the present embodiment, a quadrupole mass spectrometer is used as the measurement unit 164A. In order to operate the quadrupole mass spectrometer, a certain degree of vacuum is usually required, so that the illumination system chamber 250A has a lower pressure than the light source chamber 150A. In this case, if the pressure in the light source chamber 150A is not within the operating range of the quadrupole mass spectrometer 164A, a chamber may be provided between the quadrupole mass spectrometer 164A and the illumination system chamber 250A. The measurement unit 164A is not limited to a quadrupole mass spectrometer, and for example, a magnetic field deflection mass spectrometer or the like may be used as a mass spectrometer.

  The determination unit 170A determines the performance of the light source unit (light source device 100A) based on the measurement result of the measurement device 160A. That is, the determination unit 170A determines the performance state of the optical device 100A based on the measurement result (contaminant amount, gas type, partial pressure, and differential pressure) from the measurement device 160A. The determination method of the determination unit 170A is determined based on a table as specified values recorded in a memory (not shown). For example, if the type or partial pressure of the gas is greater than or equal to a specified value, the determination result is transmitted to the control unit 180A described later. The determination unit 170A is electrically connected to the measurement device 160A and the control unit 180A.

  The output device 175A outputs the determination result of the determination unit 170A. Therefore, the output device 175A is electrically connected to the determination unit 170A. The output method of the output device 175A can not only display the determination result on the liquid crystal screen but also transmit the determination result to the user by a lamp or sound. The output device 175A can also output a control result from the control unit 180A described later. In this case, the output device 175A is electrically connected to the control unit 180A.

  The control unit 180A controls the amount of light generated based on the determination result by the determination unit 170A. In this case, the control unit 180A changes the operation parameter of the generation unit 110. As the operation parameter change, for example, the light amount of light is changed, the exhaust capacity of a vacuum exhaust system (not shown) that exhausts the light source chamber 150A is increased, or the capacity of the cooling system that cools the constituent members of the generation unit 110 Is increasing. Thereby, the control unit 180A causes the partial pressure of the gas that causes the pollutant to be equal to or less than a predetermined specified amount.

  Further, as another method, the control unit 180A stops exposure and a gate valve provided between the light source and the illumination optical system in order to block the inflow of the gas causing the pollutant into the illumination optical system. Close. Then, a signal is displayed by the output device 175A to cause the user to perform a failure diagnosis. In this case, when it is determined that the change can be made by changing the operation parameter of the generation unit 110, the control unit 180A performs the exposure after changing the operation parameter described above. Furthermore, as another method, the control unit 180A stops the exposure, causes the output device 175A to display a signal, and causes the user to perform a failure diagnosis. Then, the constituent member of the generation unit 110 that has deteriorated is specified, and exposure is performed after replacement of the constituent member.

  As another method, when exposure is suspended for a long time for maintenance or other reasons, the concentration of substances (contaminants) that cause contamination such as hydrocarbons in the gas supply path increases. Cheap. Accordingly, the control unit 180A stops the exposure based on the determination by the determination unit 170A based on the measurement result (contaminant amount, gas type, partial pressure, and differential pressure) from the measurement apparatus 160A. At the same time, the control unit 180A continues to flow the gas until the partial pressure of the gas causing the pollutant becomes a predetermined specified amount or less, or stops the gas supply and exhausts the gas supply path with a vacuum pump. Exhaust gases that cause pollutants. Then, the control unit 180A restarts the exposure when the partial pressure of the gas causing the pollutant becomes equal to or less than a predetermined specified amount.

  As another method, the amount of contaminants is reduced by reducing the amount of light emitted from the light source unit. In that case, it is inevitable that the throughput is reduced, but such an option is also possible if the throughput may be slightly sacrificed.

  As a result, the exposure apparatus 1A can exhibit excellent exposure performance by preventing a decrease in throughput and resolving power by preventing a decrease in reflection of optical elements and a non-uniform illuminance. In addition, since it is easy to determine the deterioration of the constituent members, unnecessary replacement of the constituent members can be prevented and economically improved.

  Hereinafter, with reference to FIG. 4, a measuring apparatus 160B according to the third embodiment will be described. The members denoted by the same reference numerals as those in FIG. 2 are the same members as those in the first embodiment, and detailed description thereof is omitted. Here, FIG. 4 is a cross-sectional view showing configurations of the light source device 100B and the illumination optical system 200B.

  The measuring device 160B measures the amount of contaminants flowing into the illumination optical system 200B from the light source unit (light source device 100B). In this case, in this embodiment, the measurement unit 160B measures the amount of contaminant in the illumination system chamber 250B, and measures the amount of contaminant flowing into the illumination optical system 200B based on the measurement result. Yes. More specifically, a Faraday cup is used as the measuring device 160B, and the measuring device 160B detects the amount of contaminants flowing from the light source device 100B and passing through the opening 212B provided in a part of the illumination system mirror 210B. . Here, the Faraday cup is an apparatus that measures the amount of a substance received by a cup-shaped stopper. In this case, the Faraday cup cannot detect neutral particles, but measures the amount of all contaminants flowing into the illumination system chamber 250 by detecting the contaminants of charged particles generated from the generation unit 110. can do. The Faraday cup may be used in combination with a quadrupole mass spectrometer, a magnetic field deflection mass spectrometer, or the like to detect the species and amount of the contaminant. In the present embodiment, for example, a microchannel plate may be used in addition to the Faraday cup. Here, the microchannel plate is a device that two-dimensionally detects electrons, ions, vacuum ultraviolet rays, X-rays, γ-rays, and the like.

  The measuring device 160B measures the amount of contaminants flowing into the illumination optical system 200B and transmits the measurement result to the determination unit 170 described later. Further, the measuring device 160B may be arranged to be drivable between the aperture 152b and the illumination system mirror 210B. In that case, at the time of exposure, the measuring device 160B is driven so as to be out of the exposure optical path. Furthermore, the measuring device 160B may measure at predetermined time intervals during the generation of the plasma PL. Further, in the measurement device 160B, a detection device for identifying the type of gas flowing in may be disposed in the vicinity of the aperture 152b. In this case, the state of the light source unit 100B can be determined in advance by detecting the gas related to the deterioration of the light source unit 100B in the inflowing gas.

  The determination unit 170B determines the performance of the light source unit (light source device 100B) based on the measurement result of the measurement device 160B. That is, the determination unit 170B determines the performance state of the optical device 100B based on the measurement result (contaminant inflow amount) from the measurement device 160B. The determination method of the determination unit 170B is determined based on a table as a prescribed value recorded in a memory (not shown). For example, if the inflow amount of the pollutant is equal to or greater than a specified value, the determination result is transmitted to the control unit 180B described later. Determination unit 170B is electrically connected to measurement device 160B and control unit 180B.

  The output device 175B outputs the determination result of the determination unit 170B. Therefore, the output device 175B is electrically connected to the determination unit 170B. The output method of the output device 175B can not only display the determination result on the liquid crystal screen but also transmit the determination result to the user by a lamp or sound. The output device 175B can also output a control result from the control unit 180B described later. In this case, the output device 175B is electrically connected to the control unit 180B.

  The control unit 180B controls the amount of light generated based on the determination result by the determination unit 170B. In this case, the control unit 180B changes the operation parameter of the generation unit 110. As the change of the operation parameter, for example, the capacity of the cooling system for changing the light quantity, increasing the exhaust capacity of a vacuum exhaust system (not shown) that exhausts the light source chamber 150B, or cooling the constituent members of the generation unit 110 Is increasing. Thereby, the control unit 180B causes the partial pressure of the gas that causes the pollutant to be equal to or less than a predetermined specified amount. As another method, the control unit 180B stops the exposure, causes the output device 175B to display a signal, and causes the user to perform a failure diagnosis. In this case, when it is determined that the change can be made by changing the operation parameter of the generation unit 110, the control unit 180B performs the exposure after changing the operation parameter described above.

  Further, as another method, the control unit 180B stops the exposure, and in order to block the inflow of the gas causing the contaminant into the illumination optical system, a gate valve provided between the light source and the illumination optical system. Close. And a signal is displayed by the output device 175B, and a user is made to perform a failure diagnosis. In this case, when it is determined that the change can be made by changing the operation parameter of the generation unit 110, the control unit 180B performs the exposure after changing the operation parameter described above. Furthermore, as another method, the control unit 180B stops the exposure, causes the output device 175B to display a signal, and causes the user to perform a failure diagnosis. Then, the constituent member of the generation unit 110 that has deteriorated is specified, and exposure is performed after replacement of the constituent member.

  As another method, when exposure is suspended for a long time for maintenance or other reasons, the concentration of substances (contaminants) that cause contamination such as hydrocarbons in the gas supply path increases. Cheap. Therefore, the control unit 180B stops the exposure by the determination of the determination unit 170B based on the measurement result (contaminant inflow amount) from the measurement device 160B. At the same time, the control unit 180B continues to flow the gas until the partial pressure of the gas causing the pollutant becomes a predetermined specified amount or less, or stops the gas supply and exhausts the gas supply path with a vacuum pump. Exhaust gases that cause pollutants. Then, the control unit 180B restarts the exposure when the partial pressure of the gas that causes the pollutant becomes equal to or less than a predetermined specified amount.

  As another method, the amount of contaminants is reduced by reducing the amount of light emitted from the light source unit. In that case, it is inevitable that the throughput is reduced, but such an option is also possible if the throughput may be slightly sacrificed.

  As a result, the exposure apparatus 1B can exhibit excellent exposure performance by preventing a decrease in throughput and resolving power by preventing a decrease in reflection of optical elements and a non-uniform illuminance. In addition, since it is easy to determine the deterioration of the constituent members, unnecessary replacement of the constituent members can be prevented and economically improved.

  Referring back to FIG. 1 again, the mask 300 is a reflective mask, on which a circuit pattern (or image) to be transferred is formed, and is supported and driven by the mask stage 400. The diffracted light emitted from the mask 300 is reflected by the projection optical system 500 and projected onto the object to be exposed 600. The mask 300 and the object to be exposed 600 are arranged in an optically conjugate relationship. Since the exposure apparatus 1 is a step-and-scan exposure apparatus, the pattern of the mask 300 is reduced and projected onto the exposure object 600 by scanning the mask 300 and the exposure object 600.

  The mask stage 400 supports the mask 300 and is connected to a moving mechanism (not shown). Any structure known in the art can be applied to the mask stage 400. A moving mechanism (not shown) is configured by a linear motor or the like, and can move the mask 300 by driving the mask stage 400 at least in the X direction. The exposure apparatus 1 scans the mask 300 and the exposed object 600 in a synchronized state. Here, X is the scanning direction in the surface of the mask 300 or the object 600 to be exposed, Y is the direction perpendicular to the scanning direction, and Z is the direction perpendicular to the surface of the mask 300 or the object 600 to be exposed.

  The projection optical system 500 uses a plurality of reflection mirrors (ie, multilayer mirrors) 510 to reduce and project the pattern on the mask 300 surface onto the exposure object 600 that is the image plane. The number of the plurality of mirrors 510 is about 4 to 6. In order to realize a wide exposure area with a small number of mirrors, the mask 300 and the exposed object 600 are simultaneously scanned using only a thin arc-shaped area (ring field) separated from the optical axis by a certain distance. Transfer the area. The numerical aperture (NA) of the projection optical system 500 is about 0.2 to 0.3.

  The object to be exposed 600 is a wafer in this embodiment, but widely includes a liquid crystal substrate and other objects to be exposed. A photoresist is applied to the object 600 to be exposed.

  Wafer stage 700 supports object 600 to be exposed via a wafer chuck. The wafer stage 700 moves the exposure target 600 in the XYZ directions using, for example, a linear motor. The mask 300 and the exposed object 600 are scanned synchronously. Further, the position of the mask stage 400 and the position of the wafer stage 700 are monitored by, for example, a laser interferometer or the like, and both are driven at a constant speed ratio.

  The alignment detection mechanism 800 measures the positional relationship between the position of the mask 300 and the optical axis of the projection optical system 500 and the positional relationship between the position of the exposure target 600 and the optical axis of the projection optical system 500. The positions and angles of the mask stage 400 and the wafer stage 700 are set so that the projected image coincides with a predetermined position of the object 600 to be exposed.

  The focus position detection mechanism 900 measures the focus position on the surface of the object 600 to be exposed and controls the position and angle of the wafer stage 700 so that the surface of the object 600 is always imaged by the projection optical system 500 during exposure. Keep on.

  In the exposure, the EUV light EL emitted from the light source device 100 illuminates the mask 300, and the projection optical system 500 forms an image of the pattern on the surface of the mask 300 on the surface of the object 600 to be exposed. In the present embodiment, it is possible to easily determine the deterioration of the optical element by grasping the amount of impurities in the light source device 100 by the measuring device 160. Accordingly, an economical exposure apparatus that prevents the reduction of throughput and resolving power by preventing unnecessary replacement or decrease in reflection of optical elements and non-uniformity of illuminance, and exhibits excellent exposure performance is provided. be able to.

  Next, an embodiment of a device manufacturing method using the above-described exposure apparatus 1 will be described with reference to FIGS. FIG. 5 is a flowchart for explaining how to fabricate devices (ie, semiconductor chips such as IC and LSI, LCDs, CCDs, etc.). Here, the manufacture of a semiconductor chip will be described as an example. In step 1 (circuit design), a device circuit is designed. In step 2 (mask production), a mask on which the designed circuit pattern is formed is produced. In step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the mask and the wafer. Step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer created in step 4, and includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). Including. In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device created in step 5 are performed. Through these steps, the semiconductor device is completed and shipped (step 7).

  FIG. 6 is a detailed flowchart of the wafer process in Step 4. In step 11 (oxidation), the surface of the wafer is oxidized. In step 12 (CVD), an insulating film is formed on the surface of the wafer. In step 13 (electrode formation), an electrode is formed on the wafer by vapor deposition or the like. Step 14 (ion implantation) implants ions into the wafer. In step 15 (resist process), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the exposure apparatus 1 to expose a circuit pattern on the mask onto the wafer. In step 17 (development), the exposed wafer is developed. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), the resist that has become unnecessary after the etching is removed. By repeatedly performing these steps, multiple circuit patterns are formed on the wafer. According to the device manufacturing method of the present embodiment, it is possible to manufacture a higher quality device than before. Thus, the device manufacturing method using the exposure apparatus 1 and the resulting device also constitute one aspect of the present invention.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

It is a schematic sectional drawing which shows the structure of the exposure apparatus of this invention. It is a schematic sectional drawing which shows the structure of the light source device and illumination optical system which are embodiment of the exposure apparatus shown in FIG. It is a schematic sectional drawing which shows the structure of the light source device which is another embodiment of the exposure apparatus shown in FIG. 1, and an illumination optical system. It is a schematic sectional drawing which shows the structure of the light source device which is another embodiment of the exposure apparatus shown in FIG. 1, and an illumination optical system. It is a flowchart for demonstrating manufacture of devices (semiconductor chips, such as IC and LSI, LCD, CCD, etc.). 6 is a detailed flowchart of the wafer process in Step 4 shown in FIG. 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exposure apparatus 100 Light source apparatus 110 Generation | occurrence | production part 112 Nozzle 114 Electrode 120 Debris filter 130 Condensing mirror 140 Differential exhaust chamber 150 Light source chamber 152 Aperture 160 Measuring apparatus 170 Judgment part 175 Output apparatus 180 Control part 200 Illumination optical system 210 Illumination system mirror 220 Optical Integrator 250 Illumination System Chamber

Claims (11)

An exposure optical system that illuminates a pattern with the exposure light from the light source unit that generates exposure light by plasma, and that exposes the pattern to an object to be exposed,
A measuring device for measuring the amount of contaminants flowing into the illumination optical system from the light source unit and / or detecting the type of contaminants;
An exposure apparatus comprising: a determination unit that determines the performance of the light source unit based on a measurement result and / or a detection result of the measurement device. An exposure apparatus that has an illumination optical system that illuminates a pattern using light from a light source unit that emits exposure light by plasma generated in a space surrounded by a light source chamber, and exposes the pattern onto an object to be exposed. And
A measuring device for measuring the amount of contaminants in the light source chamber and / or detecting the type of contaminants;
An exposure apparatus comprising: a determination unit that determines the performance of the light source unit based on a measurement result and / or a detection result of the measurement device.   The exposure apparatus according to claim 1, further comprising a control unit that controls the amount of light generated based on a determination result by the determination unit.   The exposure apparatus according to claim 1, further comprising an output device that outputs a determination result by the determination unit.   The exposure apparatus according to claim 1, wherein the measurement apparatus measures the gas or the contaminant at predetermined time intervals during the generation of the plasma.   The exposure apparatus according to claim 1, wherein the exposure light has a wavelength of 20 nm or less. A generator for generating light by plasma;
A chamber for storing the generation unit;
A light source device comprising: a measuring device for measuring a quantity of contaminants in the chamber and / or detecting a kind of the contaminants.   The light source device according to claim 7, further comprising: a determination unit that determines performance of the light source device based on a measurement result and / or a detection result of the measurement device.   The light source apparatus according to claim 8, wherein the exposure apparatus further includes a control unit that controls a generation amount of the light based on a determination result by the determination unit.   The light source device according to claim 8, wherein the exposure apparatus further includes an output device that outputs a determination result by the determination unit. Exposing the object to be exposed using the exposure apparatus according to any one of claims 1 to 6;
And developing the exposed object to be exposed.