Apparatus for generating extreme ultraviolet light and lithography apparatus including the same

An extreme ultraviolet (EUV) light generating apparatus includes a vessel including a first end and a second end opposite to each other and providing an internal space extending from the first end to the second end, a concave mirror adjacent to the first end of the vessel, a droplet generator supplying a droplet to the internal space of the vessel, a laser light source irradiating a laser beam to cause the droplet to emit EUV light, and a gas jet receiving a flow control gas and spraying the received flow control gas into the internal space of the vessel. The gas jet includes a ring-shaped main body including nozzles spaced apart from one another in a circumferential direction. The nozzles spray the received flow control gas in a downward direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 U. S. C. § 119 to Korean Patent Application Nos. 10-2020-0120041 and 10-2021-0037439, filed on Sep. 17, 2020 and Mar. 23, 2021, respectively, in the Korean Intellectual Property Office, the disclosures of which are incorporated by reference herein in their entirety.

BACKGROUND

The inventive concept relates to an apparatus for generating extreme ultraviolet (EUV) light and a lithography apparatus including the same.

As semiconductor devices are continuously scaled down, a lithography process using extreme ultraviolet (EUV) light is spotlighted as an alternative. A minimum process dimension (i.e., a critical dimension) of a semiconductor circuit formed by the lithography process depends on a wavelength of a light source. Therefore, in order to process a semiconductor device with finer patterns, it is desirable to use a shorter wavelength of the light source used for the lithography process. Because the EUV light has a short wavelength of about 13.5 nm, a semiconductor circuit may be manufactured with finer patterns by using the EUV light. In order to generate the EUV light, a laser-produced plasma (LPP) method of irradiating a laser beam onto a metal droplet such as tin (Sn) is widely used. A contaminated material such as debris of the metal droplet generated in a process of generating the EUV light receives an EUV light source or the EUV light, is attached to parts in the lithography apparatus performing the lithography process, and causes the lithography apparatus to have equipment defects.

SUMMARY

The inventive concept relates to an apparatus for generating extreme ultraviolet (EUV) light with improved reliability and a lithography apparatus including the same.

According to an aspect of the inventive concept, there is provided an EUV light generating apparatus including a vessel including a first end and a second end opposite to each other and providing an internal space extending from the first end to the second end, a concave mirror adjacent to the first end of the vessel, a droplet generator supplying a droplet to the internal space of the vessel, a laser light source irradiating a laser beam to the droplet in the internal space of the vessel, the irradiated droplet emitting EUV light, and a gas jet receiving a flow control gas and spraying the received flow control gas into the internal space of the vessel. The gas jet includes a ring-shaped main body including a plurality of nozzles spaced apart from one another in a circumferential direction. The plurality of nozzles spray the received flow control gas in a downward direction extending from the second end of the vessel to the first end of the vessel.

According to an aspect of the inventive concept, there is provided an EUV light generating apparatus including a vessel including a first end and a second end opposite to each other and providing an internal space extending from the first end to the second end, a concave mirror adjacent to the first end of the vessel, a droplet generator supplying a droplet to the internal space of the vessel, a laser light source irradiating a laser beam to the droplet in the internal space of the vessel, the irradiated droplet emitting EUV light, an exhaust exhausting a gas in the vessel through an exhaust port of the vessel, and a gas jet positioned between the exhaust port of the vessel and the second end of the vessel and spraying a flow control gas into the internal space of the vessel in a downward direction extending from the second end of the vessel to the first end of the vessel. The gas jet includes a ring-shaped main body mounted at an internal wall of the vessel. The ring-shaped main body includes a plurality of nozzles spaced apart from one another in a circumferential direction. Each of the plurality of nozzles is in a form of a slit extending in the circumferential direction of the ring-shaped main body. The plurality of nozzles include eight or more nozzles apart from one another in the circumferential direction of the ring-shaped main body.

According to an aspect of the inventive concept, there is provided a lithography apparatus including an EUV light generating apparatus emitting EUV light that is reflected by a mask provided to the lithography apparatus, and a substrate stage on which a substrate. The EUV light reflected from the mask irradiates on the substrate. The EUV light generating apparatus includes a vessel including a first end and a second end opposite to each other and providing an internal space extending from the first end to the second end, a concave mirror adjacent to the first end of the vessel, a droplet generator supplying a droplet to the internal space of the vessel, a laser light source irradiating a laser beam to the droplet in the internal space of the vessel, the irradiated droplet emitting the EUV light, and a gas jet receiving a flow control gas and spraying the received flow control gas into the internal space of the vessel. The gas jet includes a ring-shaped main body mounted at an internal wall of the vessel and including a plurality of nozzles apart from one another in a circumferential direction. The gas jet sprays the received flow control gas through the plurality of nozzles in a downward direction extending from the second end of the vessel to the first end of the vessel.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments of the inventive concept will be described in detail with reference to the accompanying drawings. Like reference numerals refer to like elements throughout and description thereof will not be given.

FIG.1is a diagram illustrating an extreme ultraviolet (EUV) light generating apparatus100according to exemplary embodiments of the inventive concept.FIG.2is a cross-sectional view illustrating the region II ofFIG.1.FIG.3is a perspective view illustrating a gas jet160of the EUV light generating apparatus100ofFIG.1.

Referring toFIGS.1to3, the EUV light generating apparatus100may generate EUV light EL for a lithography process. For example, the EUV light EL generated by the EUV light generating apparatus100may have a wavelength in a range of from about 4 nm to about 124 nm. In some embodiments, the EUV light EL may have a wavelength in a range of from about 4 nm to about 20 nm. In some embodiments, the EUV light EL may have a wavelength of about 13.5 nm. Terms such as “about” or “approximately” may reflect amounts, sizes, orientations, or layouts that vary only in a small relative manner, and/or in a way that does not significantly alter the operation, functionality, or structure of certain elements. For example, a range from “about 0.1 to about 1” may encompass a range such as a 0%-5% deviation around 0.1 and a 0% to 5% deviation around 1, especially if such deviation maintains the same effect as the listed range.

The EUV light generating apparatus100may be a plasma-based light source or a synchrotron radiation light source. The plasma-based light source such as an LPP light source and a discharge-produced plasma (DPP) light source generates plasma and uses light emitted by plasma. In exemplary embodiments, the EUV light generating apparatus100may be an LPP light source.

The EUV light generating apparatus100may include a vessel110, a laser light source120, a collecting mirror130, a droplet generator141, a droplet catcher145, a first gas source151, an exhaust device155, a second gas source159, and the gas jet160.

The vessel110may provide an internal space111in which the EUV light EL is generated. For example, the internal space111of the vessel110may be kept in a vacuum. By keeping the internal space111of the vessel110in a vacuum, the EUV light EL may be prevented from being absorbed into the air. For example, pressure of the internal space111of the vessel110may be about 1.0 Torr to about 1.8 Torr.

The vessel110may include a first end118and a second end119opposite to each other. The internal space111of the vessel110may extend from the first end118of the vessel110to the second end119of the vessel110. The first end118of the vessel110may be a portion of the vessel110receiving a laser beam LB used for generating the EUV light EL or a portion of the vessel110adjacent to the collecting mirror130. The second end119of the vessel110may be a portion emitting the EUV light EL generated by the vessel110.

In exemplary embodiments, the internal space111of the vessel110may be tapered so that a width thereof decreases from the first end118of the vessel110to the second end119of the vessel110. For example, the internal space111of the vessel110may be cone-shaped so that a width thereof decreases from the first end118of the vessel110to the second end119of the vessel110.

The droplet generator141may provide a plurality of droplets DL to the internal space111of the vessel110. The droplet generator141may spray the droplets DL at regular intervals. The droplet DL is a raw material for generating the EUV light EL. The EUV light EL may be generated through an interaction between the laser beam LB received by the internal space111of the vessel110and the droplet DL. For example, the laser beam LB may be irradiated onto the droplet DL. The irradiated droplet DL may absorb the energy of the laser beam LB, and may release the absorbed energy as the EUV light EL.

For example, the droplet DL may include at least one of tin (Sn), lithium (Li), and xenon (Xe). For example, the droplet DL may include at least one of Sn, a tin compound (for example, SnBr4, SnBr2, or SnH), and a tin alloy (for example, Sn—Ga, Sn—In or Sn—In—Ga).

The droplet generator141may supply the droplet DL along a path intersecting a traveling path of the laser beam LB received by the internal space111of the vessel110. For example, when the laser beam LB received by the internal space111of the vessel110travels in a first direction (for example, a Z direction), the droplet generator141may spray the droplet DL in a second direction (for example, an X direction or a Y direction) perpendicular to the first direction (for example, the Z direction). For example, the droplet generator141may spray the droplet DL on a predetermined first position P1of the internal space111of the vessel110. In the first position P1in the vessel110, a route of the droplet DL intersects the traveling path of the laser beam LB. The EUV light EL may be generated by an interaction between the droplet DL reaching the first position P1and the laser beam LB (i.e., by an irradiation of the laser beam LB on the droplet at the first position P1).

The droplet catcher145may be positioned at an end of the route of the droplet DL sprayed by the droplet generator141and may catch the droplet DL sprayed by the droplet generator141. Among the droplets DL sprayed by the droplet generator141, some droplets DL that do not interact with the laser beam LB may be caught by the droplet catcher145.

The laser light source120may output the laser beam LB to the internal space111of the vessel110. The laser beam LB provided by the laser light source120may be introduced into the vessel110through an aperture131formed in the center of the collecting mirror130and may travel toward the first position P1in the vessel110.

In exemplary embodiments, the laser light source120may output a gas laser generated by using a gas as a gain medium. For example, the laser light source120may output a carbon dioxide (CO2) laser, a helium (He)-Neon (Ne) laser, a nitrogen (N) laser, or an excimer laser.

The collecting mirror130may be adjacent to the first end118of the vessel110. The collecting mirror130may reflect the EUV light EL formed through the interaction between the laser beam LB and the droplet DL and may collect the EUV light EL in a second position P2adjacent to the second end119of the vessel110.

The collecting mirror130may have an ellipsoidal geometric structure. In some embodiments, the collecting mirror130may be a concave mirror such as an elliptical concave mirror. For example, the collecting mirror130may have the first position P1in which the laser beam LB meets the droplet DL as a first focus and the second position P2in which the EUV light EL reflected from the collecting mirror130is collected as a second focus. The second focus may be referred to as an intermediate focus.

The first gas source151may supply a gas GS1to the internal space111of the vessel110. The first gas source151may supply the gas GS1with little reactivity to the internal space111of the vessel110. For example, the gas GS1supplied by the first gas source151may include hydrogen (H2), He, argon (Ar), hydrogen bromide (HBr), or a combination of the above gases. The first gas source151may supply the gas GS1to the internal space111of the vessel110through an inlet port adjacent to the first end118of the vessel110and/or the aperture131of the collecting mirror130. InFIG.1, it is illustrated that the gas GS1supplied by the first gas source151is supplied to the internal space111of the vessel110through the aperture131of the collecting mirror130. However, the gas GS1supplied by the first gas source151may be introduced into the internal space111through a plurality of inlet ports of the vessel110adjacent to the first end118of the vessel110.

The exhaust device155may remove a gas from the internal space111of the vessel110. The exhaust device155may exhaust the gas in the internal space111of the vessel110through an exhaust port113formed at the vessel110. The exhaust port113formed at the vessel110may be between the first end118and the second end119of the vessel110. The exhaust port113may be connected to the internal space111of the vessel110. The vessel110may include one exhaust port113or a plurality of exhaust ports113. When the vessel110includes a plurality of exhaust ports113, the plurality of exhaust ports113may be positioned at substantially the same height. Terms such as “same,” “equal,” “planar,” or “coplanar,” as used herein when referring to orientation, layout, location, shapes, sizes, amounts, or other measures do not necessarily mean an exactly identical orientation, layout, location, shape, size, amount, or other measure, but are intended to encompass nearly identical orientation, layout, location, shapes, sizes, amounts, or other measures within acceptable variations that may occur, for example, due to manufacturing processes. The term “substantially” may be used herein to emphasize this meaning, unless the context or other statements indicate otherwise. For example, items described as “substantially the same,” “substantially equal,” or “substantially planar,” may be exactly the same, equal, or planar, or may be the same, equal, or planar within acceptable variations that may occur, for example, due to manufacturing processes.

The exhaust device155may include exhaust pumps connected to the plurality of exhaust ports113of the vessel110through an exhaust line157. The exhaust device155may further include a regulator for controlling an amount of a gas exhausted through the exhaust line157and a scrubber for scrubbing the gas exhausted through the exhaust line157.

The gas GS1may be supplied by the first gas source151to the internal space111of the vessel110in an updraft flow that is a gas flow from the first end118of the vessel110toward the second end119of the vessel110. For example, the gas GS1supplied by the first gas source151may rise from the first end118of the vessel110toward the second end119of the vessel110and may be exhausted to the outside of the vessel110through the exhaust port113of the vessel110. Such a flow of the gas GS1may remove a contaminant residing on an internal wall (i.e., an inner surface) of the vessel110and a surface of the collecting mirror130, and may dissipate heat of parts of the vessel110and the collecting mirror130.

The gas jet160may receive a flow control gas FCG from the second gas source159and may spray the flow control gas FCG into the internal space111of the vessel110. The flow control gas FCG for controlling airflow in the internal space111of the vessel110may include a gas with little reactivity to the vessel110. For example, the flow control gas FCG may include or may be formed of an inert gas. For example, the flow control gas FCG may include or may be formed of H2, He, Ar, HBr, or a combination of the above gases. The flow control gas FCG provided by the second gas source159may have the same material and/or material composition as those/that of the gas GS1provided by the first gas source151or a material and/or material composition different from those/that of the gas GS1provided by the first gas source151.

The gas jet160may spray the flow control gas FCG into the internal space111of the vessel110in a downward direction extending from the second end119of the vessel110to the first end118of the vessel110. For example, the gas jet160may spray the flow control gas FCG toward the collecting mirror130. The flow control gas FCG may be sprayed by the gas jet160in a downdraft flow that is a gas flow from the gas jet160adjacent to the second end119of the vessel110toward the first end118of the vessel110. The flow control gas FCG provided by the gas jet160may form the downdraft flow in the internal space111of the vessel110. For example, such downdraft flow of the flow control gas FCG may suppress the updraft flow of the gas GS1formed in the internal space111of the vessel110.

The gas jet160may include a main body161and an inlet pipe163. The inlet pipe163may receive the flow control gas FCG provided by the second gas source159. The inlet pipe163may be connected to the main body161and may transmit the flow control gas FCG provided by the second gas source159to a flow channel of the main body161.

The main body161of the gas jet160may be ring-shaped. For example, the main body161of the gas jet160may be ring-shaped to surround a central axis of the internal space111, which is cone-shaped, provided by the vessel110. In exemplary embodiments, a central axis of the main body161of the gas jet160, which is ring-shaped, may coincide with the central axis of the cone-shaped internal space111provided by the vessel110. For example, the main body161of the gas jet160may include a lower surface169aand an upper surface169bopposite to each other, and an outer peripheral surface (i.e., an outer side surface)169dand an inner peripheral surface (i.e., an inner side surface)169copposite to each other. The lower surface169aof the main body161may face the first end118of the vessel110and the upper surface169bof the main body161may face the second end119of the vessel110. For example, the lower surface169amay be closer to the first end118of the vessel110than the second end119of the vessel110, and the upper surface169bmay be closer to the second end119of the vessel110than the first end118. The outer peripheral surface169dof the main body161may contact the internal wall of the vessel110. It will be understood that when an element is referred to as being “connected” or “coupled” to or “on” another element, it can be directly connected or coupled to or on the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to, or “directly disposed on” another element, or as “contacting” or “in contact with” another element, there are no intervening elements present at the point of contact.

The main body161of the gas jet160may be fixed onto the internal wall of the vessel110. In exemplary embodiments, the main body161of the gas jet160may be fixed to the vessel110by being inserted into a mounting groove112provided in the internal wall of the vessel110.

In exemplary embodiments, the gas jet160may include or may be formed of metal. For example, the gas jet160may include or may be formed of aluminum (Al), tungsten (W), or a combination of Al and W. Alternatively, in exemplary embodiments, the gas jet160may include or may be formed of ceramic or polymer. For example, the gas jet160may include or may be formed of glass, quartz, or Teflon.

The main body161of the gas jet160may include a plurality of nozzles162spaced apart from one another in a circumferential direction. In some embodiments, each of the plurality of nozzles162may be an opening of the main body161. The opening may be formed at the lower surface169aand connected to a region enclosed by the main body161. The gas jet160may spray the flow control gas FCG into the internal space111of the vessel110through the plurality of nozzles162. The flow control gas FCG may be sprayed into the internal space111of the vessel110through the plurality of nozzles162in a constant direction. The flow control gas FCG sprayed on the internal space111of the vessel110through the plurality of nozzles162may have the downdraft that is the gas flow in a direction extending from the second end119of the vessel110to the first end118of the vessel110. For example, the flow control gas FCG may be sprayed into the internal space111of the vessel110through the plurality of nozzles162in an angle in a predetermined angular range with respect to a reference direction (RD ofFIG.5). The reference direction RD may be a direction of the central axis of the internal space111, which is cone-shaped, or a direction from the second position P2of the vessel110to the first position P1of the vessel110. For example, a flowing direction of the flow control gas FCG sprayed from each of the plurality of nozzles162of the gas jet160may be inclined with respect to the reference direction RD. The flowing direction of the flow control gas FCG sprayed from each of the plurality of nozzles162of the gas jet160may have a distribution with an angular range of about −30° to about +30° with respect to the reference direction RD.

The flow control gas FCG with the same flux may be sprayed into the internal space111of the vessel110through the plurality of nozzles162. For example, each of the plurality of nozzles162may spray the same flux of the flow control gas FCG. The gas jet160may provide a uniform downdraft in the circumferential direction of the gas jet160by spraying the flow control gas FCG through the plurality of nozzles162in the constant direction and with uniform flux. The plurality of nozzles162may be spaced apart from one another in the circumferential direction.

The gas jet160may be adjacent to the second position P2in which the EUV light EL reflected from the collecting mirror130is collected (i.e., focused). The gas jet160may be mounted in the internal space111of the vessel110between the exhaust port113of the vessel110and the second end119of the vessel110(i.e., mounted at the internal wall of the vessel110). The gas jet160may be positioned at a first height with reference to the first end118of the vessel110. The exhaust port113of the vessel110may be positioned at a second height with reference to the first end118of the vessel110. The first height may be greater than the second height.

The gas jet160may prevent the updraft formed in the internal space111of the vessel110from moving toward the second end119of the vessel110beyond a mounting position of the gas jet160and may purge the gas of the internal space111of the vessel110and the contaminant included in the gas of the internal space111of the vessel110to the outside of the vessel110through the exhaust port113by spraying the flow control gas FCG downward (that is, in a direction extending from the second end119of the vessel110to the first end118of the vessel110).

A spitting phenomenon, in which debris of the droplets DL is accumulated on the internal wall of the vessel110adjacent to the second end119of the vessel110and interacts with the gas of the internal space111of the vessel110to grow into particles each having a size of about 1 micrometer, may occur in the vessel110. The particles generated by the spitting phenomenon may be emitted to the outside of the vessel110through the second end119of the vessel110. The particles generated by the spitting phenomenon are emitted to the outside through the second end119of the vessel110. The particles may be attached to other parts of a lithography apparatus and may cause the lithography apparatus to have equipment defects. For example, when the particles generated by the spitting phenomenon are attached to a mask, the reliability of the lithography process may remarkably deteriorate due to mask defects.

In exemplary embodiments, the gas jet160may prevent the updraft from rising along the internal wall of the vessel110by being mounted around the second end119of the vessel110and spraying the flow control gas FCG downward. Therefore, because the debris of the droplet DL is prevented from moving near the second end119of the vessel110with the airflow rising along the internal wall of the vessel110, the debris of the droplet DL may be prevented from being accumulated near the second end119of the vessel110. The debris of the droplet DL is prevented from being accumulated near the second end119of the vessel110, and the mask defects caused by the particles generated by the spitting phenomenon may be reduced and the reliability of the lithography process by using the lithography apparatus may be improved.

FIG.4is a view illustrating an airflow simulation result in the internal space111of the vessel110.

InFIG.4, on cross-sections of the internal space111of the vessel110, which are taken along the lines A-A′, B-B′, and C-C′ ofFIG.3, an airflow301including the debris of the droplet DL is illustrated.

Referring toFIG.4together withFIGS.1to3, because the gas jet160provides the downdraft having the constant direction and the uniform flux in the circumferential direction of the gas jet160, it may be noted that the rise of the airflow301including the debris of the droplet DL is suppressed over the whole region of the internal space111. For example, it may be noted that a height303aof the airflow301including the debris of the droplet DL in the cross-section taken along the line A-A′, a height303bof the airflow301including the debris of the droplet DL in the cross-section taken along the line B-B′, and a height303cof the airflow301including the debris of the droplet DL in the cross-section taken along the line C-C′ are less than a mounting height160H of the gas jet160.

When the downdraft provided by the gas jet160is not uniform in the circumferential direction of the gas jet160, there is a high probability that the airflow301including the debris of the droplet DL may reach an upper region of the internal space111, which is adjacent to the second end119of the vessel110, beyond the mounting height160H of the gas jet160through a portion in which the downdraft is weak.

In exemplary embodiments, the gas jet160may provide the uniform downdraft to the internal space111in the circumferential direction of the gas jet160so that a high level of consistency for flow control is provided. Therefore, because the rise of the airflow301along the internal wall of the vessel110is uniformly suppressed over the whole region of the internal space111, a point in which the rise of the airflow301is not suppressed well may be removed. Therefore, because the debris of the droplet DL is prevented from being accumulated near the second end119of the vessel110, the equipment defects and mask defects caused by the particles generated by the spitting phenomenon may be reduced and the reliability of the lithography process using the lithography apparatus may increase.

FIG.5is a cross-sectional view illustrating a part of an EUV light generating apparatus including a gas jet160aaccording to exemplary embodiments of the inventive concept. InFIG.5, a portion corresponding to the region II ofFIG.1is illustrated.

Referring toFIG.5, the gas jet160amay spray the flow control gas FCG in a direction inclined at a constant angle radially outward with respect to the reference direction RD. A plurality of nozzles162provided in the gas jet160aare exposed through a lower surface169aof a main body161of the gas jet160aand extend in the direction inclined at the constant angle radially outward with respect to the reference direction RD so as to spray the flow control gas FCG in the direction inclined at the constant angle radially outward with respect to the reference direction RD. For example, each of the plurality of nozzles162may be an opening of the main body161. The opening may have an inclined sidewall extending at a first inclined angle (e.g., an angle IA1) with respect to the reference direction RD so that the downdraft flow generated from the opening of the gas jet160amay be directed toward the internal wall of the vessel110.

In exemplary embodiments, an angle IA1between the direction in which the flow control gas FCG is sprayed through the plurality of nozzles162and the reference direction RD may be greater than about 0° and less than about 30° (i.e., may be in a range of from about 0° and about) 30°.

FIG.6is a cross-sectional view illustrating a part of an EUV light generating apparatus including a gas jet160baccording to exemplary embodiments of the inventive concept. InFIG.6, a portion corresponding to the region II ofFIG.1is illustrated.

Referring toFIG.6, the gas jet160bmay spray the flow control gas FCG in a direction inclined at a constant angle radially inward with respect to the reference direction RD. A plurality of nozzles162provided in the gas jet160bare exposed through a lower surface169aof a main body161of the gas jet160band extend in the direction inclined at the constant angle radially inward with respect to the reference direction RD so as to spray the flow control gas FCG in the direction inclined at the constant angle radially inward with respect to the reference direction RD. For example, each of the plurality of nozzles162may be an opening of the main body161. The opening may have an inclined sidewall extending a second inclined angle (e.g., an angle IA2) with respect to the reference direction RD so that the downdraft flow generated from the opening of the gas jet160amay be directed away from the internal wall of the vessel110.

In exemplary embodiments, an angle IA2between the direction in which the flow control gas FCG is sprayed through the plurality of nozzles162and the reference direction RD may be greater than about 0° and less than about 30° (i.e., may be in a range of from about 0° and about) 30°.

FIG.7is a cross-sectional view illustrating a part of an EUV light generating apparatus including a gas jet160caccording to exemplary embodiments of the inventive concept. InFIG.7, a portion corresponding to the region II ofFIG.1is illustrated.

Referring toFIG.7, the gas jet160cmay include a plurality of flow guide plates165connected to a main body161and controlling a direction in which the flow control gas FCG is sprayed through a plurality of nozzles162. The plurality of flow guide plates165may extend downward from a lower surface169aof the main body161. The plurality of flow guide plates165may extend from the lower surface169aof the main body161in the reference direction RD.

The plurality of flow guide plates165may extend in a circumferential direction of the main body161of the gas jet160c. For example, each of the plurality of nozzles162is in the form of a slit extending in the circumferential direction of the main body161of the gas jet160c, and each of the plurality of flow guide plates165may extend in the circumferential direction to have a length corresponding to a length of each of the plurality of nozzles162in the circumferential direction. For example, the length of each of the plurality of flow guide plates165in the circumferential direction may be equal to or greater than the length of each of the plurality of nozzles162in the circumferential direction.

The number of flow guide plates165provided in the gas jet160cmay be equal to the number of nozzles162. For example, the gas jet160cincludes the plurality of nozzles162spaced apart from one another in the circumferential direction, and each of the plurality of flow guide plates165for guiding the flow control gas FCG may be arranged on an exit side of a corresponding one of the plurality of nozzles162.

In exemplary embodiments, in order to control a flow direction of the flow control gas FCG sprayed through the plurality of nozzles162, the direction in which the plurality of flow guide plates165extend may be controlled. In some embodiment, the flow control gas FCG sprayed through each of the plurality of nozzles162may flow along an extending surface of a corresponding flow guide plate165. In some embodiment, each of the plurality of nozzles162may be an opening of the main body161, and a sidewall of the opening and an extending surface of a corresponding flow guide plate165may extend in the reference direction RD and may be connected with each other. Each of the plurality of guide plates165may be arranged on an exit side of a corresponding nozzle as shown inFIGS.5and6, as shown inFIG.7. InFIGS.5and6, the sidewalls of the openings of the main body161, which are the plurality of nozzles162, are inclined at the angles IA1and IA2, respectively, and extending surfaces of a plurality of guide plates inFIG.5may extend at the angle IA1with respect to the reference direction RD, and extending surfaces of a plurality of guide plates inFIG.6may extend at the angle IA2with reference to the reference direction RD.

In exemplary embodiments, like in the direction in which the flow control gas FCG is sprayed by the gas jet160aas illustrated with reference toFIG.5, the plurality of flow guide plates165may guide the flow control gas FCG in the direction inclined at the constant angle radially outward with respect to the reference direction RD. The plurality of flow guide plates165may extend in the direction inclined at the constant angle radially outward with respect to the reference direction RD from the lower surface169aof the main body161so that the flow control gas FCG may flow to be inclined radially outward with respect to the reference direction RD.

In exemplary embodiments, like in the direction in which the flow control gas FCG is sprayed by the gas jet160bas illustrated with reference toFIG.6, the plurality of flow guide plates165may guide the flow control gas FCG in the direction inclined at the constant angle radially inward with respect to the reference direction (RD ofFIG.6). So that the flow control gas FCG flows to be inclined radially inward with respect to the reference direction (RD ofFIG.6), the plurality of flow guide plates165may be arranged between the internal wall of the vessel110and the plurality of nozzles162and may extend in the direction inclined at the constant angle radially inward with respect to the reference direction (RD ofFIG.6) from the lower surface169aof the main body161.

FIG.8is a cross-sectional view illustrating a part of an EUV light generating apparatus including a gas jet160daccording to exemplary embodiments of the inventive concept. InFIG.8, a portion corresponding to the region II ofFIG.1is illustrated.

Referring toFIG.8, a plurality of nozzles162aof the gas jet160dmay be exposed through an inner peripheral surface169cof a main body161and the flow control gas FCG may be sprayed through the plurality of nozzles162a. The gas jet160dmay include a plurality of flow guide plates165aarranged on the inner peripheral surface169cof the main body161and controlling a direction in which the flow control gas FCG is sprayed through the plurality of nozzles162a. The plurality of flow guide plates165amay extend downward so as to cover the plurality of nozzles162aprovided in the inner peripheral surface169cof the main body161and so that the flow control gas FCG has the downdraft. The plurality of flow guide plates165amay extend downward (that is, in a direction extending from the second end119of the vessel110to the first end118of the vessel110or toward the controlling mirror130) from an upper end connected to the inner peripheral surface169cof the main body161. For example, each of the plurality of flow guide plates165amay include an upper end connected to the inner peripheral surface169cof the main body161, and a portion extending downward from the upper end toward the controlling mirror130. An upper end of each flow guide plate165amay be arranged on an exit side of a corresponding nozzle as shown inFIG.7, except that the opening of the main body161is formed at the inner peripheral surface169c.

The plurality of flow guide plates165amay extend in a circumferential direction of the main body161of the gas jet160d. For example, each of the plurality of nozzles162ais in the form of a slit extending in the circumferential direction of the main body161of the gas jet160d, and each of the plurality of flow guide plates165amay extend in the circumferential direction to have a length corresponding to a length of each of the plurality of nozzles162ain the circumferential direction. For example, the length of each of the plurality of flow guide plates165ain the circumferential direction may be equal to or greater than the length of a corresponding one of the plurality of nozzles162ain the circumferential direction.

The number of flow guide plates165aprovided in the gas jet160dmay be equal to the number of nozzles162a. For example, the gas jet160dincludes the plurality of nozzles162aspaced apart from one another in the circumferential direction, and each of the plurality of flow guide plates165afor guiding the flow control gas FCG may be arranged on an exit side of each of the plurality of nozzles162a.

In exemplary embodiments, in order to control a flow direction of the flow control gas FCG sprayed through the plurality of nozzles162a, the direction in which the plurality of flow guide plates165aextend may be controlled. In some embodiment, the flow control gas FCG sprayed through each of the plurality of nozzles162amay flow along an extending surface of a corresponding flow guide plate165a. In some embodiment, each of the plurality of nozzles162amay be an opening of the main body161, and a sidewall of the opening and an extending surface of a corresponding flow guide plate165amay be connected with each other. Each of the plurality of guide plates165amay be arranged on an exit side of a corresponding nozzle as shown inFIG.8.

In exemplary embodiments, like in the direction in which the flow control gas FCG is sprayed by the gas jet160aas illustrated with reference toFIG.5, the plurality of flow guide plates165amay guide the flow control gas FCG in the direction inclined at the constant angle radially outward with respect to the reference direction RD. The plurality of flow guide plates165amay extend in the direction inclined at the constant angle radially outward with respect to the reference direction RD from the upper end connected to the inner peripheral surface169cof the main body161so that the flow control gas FCG may flow in the direction inclined at the constant angle radially outward with respect to the reference direction RD.

In exemplary embodiments, like in the direction in which the flow control gas FCG is sprayed by the gas jet160bas illustrated with reference toFIG.6, the plurality of flow guide plates165amay guide the flow control gas FCG in the direction inclined at the constant angle radially inward with respect to the reference direction (RD ofFIG.6). The plurality of flow guide plates165amay extend in the direction inclined at the constant angle radially inward with respect to the reference direction (RD ofFIG.6) from the upper end connected to the inner peripheral surface169cof the main body161and may guide the flow control gas FCG in the direction inclined at the constant angle radially inward with respect to the reference direction (RD ofFIG.6).

FIG.9is a cross-sectional view illustrating a horizontal cross-section of a gas jet160eaccording to exemplary embodiments of the inventive concept.

Referring toFIG.9together withFIGS.1and2, the gas jet160emay include a plurality of nozzles162spaced apart from one another in a circumferential direction of a main body161. The plurality of nozzles162may be exposed through a lower surface169aof the main body161and may spray the flow control gas FCG downward. Each of the plurality of nozzles162may be in the form of a slit extending in the circumferential direction of the main body161.

In exemplary embodiments, lengths of the plurality of nozzles162extending in the circumferential direction of the main body161may be equal to one another. A distance between two adjacent nozzles among the plurality of nozzles162may be constant.

InFIG.9, the gas jet160eis illustrated as including eight nozzles162. However, the number of nozzles162included in the gas jet160emay be less than or greater than 8.

The main body161of the gas jet160emay include distribution channels164dividing the flow control gas FCG transmitted by inlet pipes163and transmitting the divided flow control gas FCG to the two or more nozzles162.

In exemplary embodiments, the distribution channels164may include first distribution channels164aand second distribution channels164b. Each of the first distribution channels164amay be connected to a corresponding one of the inlet pipes163and may extend from an exit of the corresponding one of the inlet pipes163to two second distribution channels164b. For example, each first distribution channel164amay have a first end connected to one of the two second distribution channels164b, and a second end connected to the other of the two second distribution channels164b. Each of the second distribution channels164bmay extend from each of exits of the first distribution channels164ato the two nozzles162. For example, each second distribution channel164bmay include a first end connected to one of the two nozzles162, and a second end connected to the other of the two nozzles162. Each of the first distribution channels164amay transmit the flow control gas FCG transmitted through each of the inlet pipes163to the two second distribution channels164b. For example, the flow control gas FCG transmitted to each of the first distribution channels164athrough each of the inlet pipes163may be divided into two paths in each of the first distribution channels164a. The two second distribution channels164bmay be connected to opposite ends of the two paths of each of the first distribution channels164a, respectively. Each of the two second distribution channels164bmay transmit the flow control gas FCG transmitted by each of the first distribution channels164ato the two nozzles162. For example, the flow control gas FCG transmitted to the two second distribution channels164bthrough each of the first distribution channels164amay be divided into two paths (i.e., two divided flows) in the two second distribution channels164b.

In exemplary embodiments, a diameter (or a width) of each of the first distribution channels164aand the second distribution channels164bmay be in a range of from about 1 mm to about 10 mm.

As illustrated inFIG.9, the gas jet160emay include the two inlet pipes163connected to opposite sides of the main body161thereof. Each of the two inlet pipes163may be connected to the four nozzles162through the one first distribution channel164aand the two second distribution channels164b. For example, a flow of the flow control gas FCG transmitted through the one inlet pipe163may be divided into two divided flows of the flow control gas FCG, and each of the divided flows of the flow control gas FCG may be transmitted to corresponding four nozzles162through the one distribution channel164of the main body161. Because the flow control gas FCG may be uniformly transmitted to the plurality of nozzles162through the distribution channels164of the main body161, the flow control gas FCG with the uniform flux may be sprayed through the plurality of nozzles162.

InFIG.9, it is illustrated that the flow control gas FCG is divided twice until the flow control gas FCG reaches each of the plurality of nozzles162from the one inlet pipe163so that the one inlet pipe163is connected to the four nozzles162. However, the number of nozzles162connected to the one inlet pipe163may be greater than 4. For example, the distribution channel164may be configured so that the flow control gas FCG is divided three times until the flow control gas FCG reaches each of the plurality of nozzles162from the one inlet pipe163so that the one inlet pipe163is connected to the eight nozzles162.

FIG.10is a cross-sectional view illustrating a horizontal cross-section of a gas jet160faccording to exemplary embodiments of the inventive concept.

Referring toFIG.10together withFIGS.1and2, the gas jet160fmay include branch pipes166extending between inlet pipes163and a main body161. The branch pipes166may be connected to the main body161so that internal channels of the branch pipes166are connected to an internal channel of the main body161. The branch pipes166may divide the flow control gas FCG transmitted by the inlet pipes163and may transmit the divided flow control gas FCG to two or more nozzles162provided in the main body161.

In exemplary embodiments, the branch pipes166may include first branch pipes166aand second branch pipes166b. Each of the first branch pipes166amay be connected to a corresponding one of the inlet pipes163and may extend from an exit of the corresponding one of the inlet pipes163to two second branch pipes166b. For example, each first branch pipe166amay have a first end connected to one of the two second branch pipes166b, and a second end connected to the other of the two second branch pipes166b. Each of the second branch pipes166bmay extend from each of exits of the first branch pipes166ato the two nozzles162provided in the main body161. For example, each second branch pipe166bmay include a first end connected to one of the two nozzles162, and a second end connected to the other of the two nozzles162. Each of the first branch pipes166amay transmit the flow control gas FCG transmitted through each of the inlet pipes163to the two second branch pipes166b. For example, the flow control gas FCG transmitted to each of the first branch pipes166athrough each of the inlet pipes163may be divided into two paths through the divided channels of each of the first branch pipes166a. The two second branch pipes166bmay be respectively connected to opposite ends of the two paths of each of the first branch pipes166a. Each of the two second branch pipes166bmay transmit the flow control gas FCG transmitted by each of the first branch pipes166ato the two nozzles162. For example, the flow control gas FCG transmitted to the second branch pipes166bthrough each of the first branch pipes166amay be divided into two paths (i.e., two divided flows) in the second branch pipes166b.

In exemplary embodiments, a diameter (or a width) of each of the channels of the first branch pipes166aand the channels of the second branch pipes166bmay be in a range of from about 1 mm to about 10 mm.

As illustrated inFIG.10, the gas jet160fmay include the two inlet pipes163combined with opposite sides of the main body161thereof. Each of the two inlet pipes163may be connected to the four nozzles162through the one first branch pipe166aand the two second branch pipes166b. For example, a flow of the flow control gas FCG transmitted through the one inlet pipe163may be divided into two divided flows of the flow control gas FCG, and each of the divided flows of the flow control gas FCG may be transmitted to corresponding four nozzles162through the one branch pipe166. Because the flow control gas FCG may be uniformly separated by the branch pipes166and may be supplied to the plurality of nozzles162, the flow control gas FCG with the uniform flux may be sprayed through the plurality of nozzles162.

InFIG.10, it is illustrated that the flow control gas FCG is divided twice until the flow control gas FCG reaches each of the plurality of nozzles162from the one inlet pipe163so that the one inlet pipe163is connected to the four nozzles162. However, the number of nozzles162connected to the one inlet pipe163may be greater than 4. For example, the branch pipe166may be configured so that the flow control gas FCG is divided three times until the flow control gas FCG reaches each of the plurality of nozzles162from the one inlet pipe163so that the one inlet pipe163is connected to the eight nozzles162.

FIG.11is a block diagram schematically illustrating a lithography apparatus200according to exemplary embodiments of the inventive concept.

Referring toFIG.11together withFIGS.1to3, the lithography apparatus200may include an EUV light generating apparatus210, an illumination optical system220, a mask support230, a projection optical system240, and a substrate stage250. The EUV light generating apparatus210included in the lithography apparatus200may output EUV light EL, and the lithography apparatus200may perform a lithography process by using the EUV light EL. The EUV light generating apparatus210may correspond to the EUV light generating apparatus100including the gas jet160as described with reference toFIGS.1to3or an EUV light generating apparatus including one of the gas jets160a,160b,160c,160d,160e, and160fas described with reference toFIGS.5to10.

The illumination optical system220may include a plurality of mirrors and may transmit the EUV light EL output from the EUV light generating apparatus210to a mask M. For example, the EUV light EL from the EUV light generating apparatus210may be reflected from the plurality of mirrors in the illumination optical system220and may be incident on the mask M arranged on the mask support230.

The mask M may be a reflective mask including a reflection region and a non-reflective region and/or a mid-reflection region. The mask M may include or may be formed of a reflective multilayer for reflecting the EUV light EL and an absorbent layer pattern formed on the reflective multilayer on a substrate W including a low thermal expansion coefficient material (LTEM) such as quartz. The reflective multilayer may have, for example, a structure in which molybdenum (Mo) layers and silicon (Si) layers are alternately stacked on each other in dozens of layers. The absorbent layer may include or may be formed of, for example, TaN, TaNO, TaBO, nickel (Ni), gold (Au), silver (Ag), carbon (C), tellurium (Te), platinum (Pt), palladium (Pd), or chrome (Cr). However, the material of the reflective multilayer and the material of the absorbent layer are not limited to the above-described materials. The absorbent layer may correspond to the non-reflective region and/or the mid-reflection region.

The mask M reflects the EUV light EL incident through the illumination optical system220, and the reflected EUV light EL may be incident on the projection optical system240. For example, the mask M may reflect the light incident through the illumination optical system220, and the reflected light may have patterns of intensity based on a shape of the pattern including the reflective multilayer. The reflected light may be projected onto the substrate W. The absorbent layer on the substrate W may receive the projection light via the projection optical system240. The projection light may have diffraction patterns with at least secondary diffraction order due to the pattern on the mask M. The projection light may form an image corresponding to the pattern of the mask M on the substrate W. The projection light may pass through the projection optical system240and may be incident on the substrate W via the projection optical system240with shape information of the pattern on the mask M. The substrate W may be a substrate including a semiconductor material such as Si, for example, a wafer.

The substrate W may be arranged on the substrate stage250. The substrate stage250may move in a direction parallel with or perpendicular to a main surface of the substrate stage250with the substrate W mounted thereon.

The projection optical system240may include a plurality of mirrors241and243. InFIG.11, only the two mirrors241and243are illustrated in the projection optical system240for the sake of convenience. The projection optical system240may include more mirrors. For example, the projection optical system240may include four to eight mirrors.

In exemplary embodiments, the EUV light generating apparatus210may prevent the particles from being generated due to the spitting phenomenon by preventing the debris of the droplet DL from being accumulated near the second end119of the vessel110. According to the example embodiments of the inventive concept, the equipment defects caused by the particles generated due to the spitting phenomenon, in particular, the mask defects caused by the particles attached to the mask M, are reduced, and the reliability of the lithography process using the lithography apparatus200may increase.