Light source device

Abstract

To provide a light source device capable of controlling debris.SOLUTION: The light source device 1 according to the present disclosure includes a target holder 100, the target holder 100 including a bottom part 110, a cylindrical part 120 having an opening at one end and communicating with the bottom part 110 at the other end, and an opposing wall 133 surrounded by the cylindrical part 120 and disposed on the rotation axis R side, the opposing wall 133 opposing an inner wall 123 of the cylindrical part 120, the inner wall 123 holding a target material TM at an irradiation position PT. The opposing wall 133 intersects with a perpendicular line 1280 that is perpendicular to the rotation axis R and passes through the irradiating position PT, the length D1 from the rotation axis R to the bottom end 135 is greater than the length P0 from the rotation axis R to the intersection point D0, and the exciting light LR irradiates the irradiating position PT through an irradiating space 136 that is a space between the opening end 134 and the opening cylinder 124.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a light source device. [Background technology]

[0002] Patent Document 1 describes a crucible-type EUV (Extreme Ultraviolet) light source. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-001924 Summary of the Invention [Problem to be solved by the invention]

[0004] Controlling debris generated from a target material in a light source device such as an EUV light source, for example, reducing the scattering of debris, helps to stabilize the operation of the light source device.

[0005] The object of the present disclosure is to solve such problems and to provide a light source device that can control debris. [Means for solving the problem]

[0006] The light source device according to the present disclosure comprises a target holding section, the target holding section including a bottom, a cylindrical section having an open end and the other end connected to the bottom, and an opposing wall arranged on the rotation axis side surrounded by the cylindrical section, the opposing wall opposing the inner wall of the cylindrical section, the inner wall holding a target material that generates plasma when irradiated with excitation light at an irradiation position, the opposing wall intersecting with a perpendicular line that is perpendicular to the rotation axis and passes through the irradiation position, the distance from the rotation axis to the bottom-side end, which is the end of the opposing wall on the bottom side, is greater than the distance from the rotation axis to the intersection of the perpendicular line on the opposing wall, the cylindrical section including an opening-side cylindrical section at an opening-side portion and a bottom-side cylindrical section at a bottom-side portion, the excitation light irradiating the irradiation position through an irradiation space, which is the space between the opening-side cylindrical section and the opening-side end, which is the end of the opposing wall opposite the bottom-side end.

[0007] In the light source device, a region may be included between the intersection of the opposing wall with the perpendicular line and the opening side end, in which the distance from the rotation axis is smaller than the distance from the rotation axis to the intersection.

[0008] In the light source device, the opposing wall may have a distance to the rotation axis that gradually decreases from the bottom end toward the opening end.

[0009] In the light source device, the distance from the bottom to the opening-side end may be greater than the distance from the bottom to the opening-side cylindrical portion.

[0010] In the light source device, the distance from the rotation axis to the opening-side cylindrical portion may be shorter than the distance from the rotation axis to the inner wall.

[0011] In the light source device, the illumination space may be formed over the entire circumference along a rotation direction around the rotation axis.

[0012] In the light source device, the opposing wall may be formed over the entire circumference along a rotation direction around the rotation axis.

[0013] In the above light source device, the opening side end may have one or more slits that are formed along the entire circumference of the rotation axis in a direction of rotation around the rotation axis, and whose distance to the rotation axis is greater than the distance from the intersection to the rotation axis, and that are arranged along the direction of rotation around the rotation axis so as to expose a portion of the irradiation space.

[0014] In the light source device, the target material may be refilled through the irradiation space.

[0015] In the light source device, the opposing wall may be at a temperature equal to or higher than the melting point of the target material, and the target material may be refilled by contacting the opposing wall.

[0016] In the light source device, the opening of the cylindrical portion may be oriented substantially downward or substantially upward in the direction of gravity.

[0017] In the light source device, the opening of the cylindrical portion may be oriented substantially downward in the direction of gravity, and the opening-side cylindrical portion may have a groove recessed downward in the direction of gravity.

[0018] The light source device may further include a cover or debris container that covers the opening side of the cylindrical portion from below, the opening of the cylindrical portion facing substantially downward in the direction of gravity.

[0019] The light source device may further include an optical path cover that covers the optical path of at least one of the excitation light and the light generated from the plasma, and the optical path cover may be attached to the cover portion, disposed inside the debris storage container, or disposed between the cylindrical portion and the debris storage container.

[0020] In the light source device, the light path cover may include a plurality of portions.

[0021] In the light source device, the opening of the cylindrical portion may be oriented approximately downward in the direction of gravity, and the light source device may further include a sensor positioned to detect light generated from the plasma that passes through at least one of the vicinity of the end of the opening-side cylindrical portion and the vicinity of the opening-side end. [Effects of the Invention]

[0022] According to the present disclosure, debris can be controlled. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a cross-sectional view illustrating a light source device according to a first embodiment. [Figure 2] 2 is a plan view illustrating a target holding unit, a generating unit, and an output optical system in the light source device according to the first embodiment. FIG. [Figure 3] 2 is a plan view illustrating a target holding unit and an output optical system in the light source device according to the first embodiment. FIG. [Figure 4] 3 is a cross-sectional view illustrating a target material held on an inner wall of a cylindrical portion of a target holding portion in the light source device according to the first embodiment. FIG. [Figure 5] 3 is a cross-sectional view illustrating a target material held on an inner wall of a cylindrical portion of a target holding portion in the light source device according to the first embodiment. FIG. [Figure 6] 3 is a cross-sectional view illustrating a target material held on an inner wall of a cylindrical portion of a target holding portion in the light source device according to the first embodiment. FIG. [Figure 7] 3 is a cross-sectional view illustrating a target material held on an inner wall of a cylindrical portion of a target holding portion in the light source device according to the first embodiment. FIG. [Figure 8] 3 is a cross-sectional view illustrating a target material held on an inner wall of a cylindrical portion of a target holding portion in the light source device according to the first embodiment. FIG. [Figure 9] 10 is a plan view illustrating a target holding portion of a light source device according to a first modification of the first embodiment. FIG. [Figure 10]10 is a cross-sectional view illustrating a target holding portion of a light source device according to a first modification of the first embodiment. [Figure 11] 10 is a cross-sectional view illustrating a target holding portion of a light source device according to a second modification of the first embodiment. [Figure 12] FIG. 10 is a cross-sectional view illustrating a light source device 2 according to a second embodiment. [Figure 13] 10 is a cross-sectional view illustrating a cylindrical portion of a target holding portion in a light source device according to a first modification of the second embodiment. FIG. [Figure 14] 10 is a cross-sectional view illustrating an example of the arrangement of sensors in a light source device according to Modification 2 of Embodiment 2. FIG. [Figure 15] 10 is a cross-sectional view illustrating an example of a debris container in a light source device according to a third modification of the second embodiment. FIG. [Figure 16] FIG. 10 is a cross-sectional view illustrating a light source device 3 according to a third embodiment. [Figure 17] 13 is a cross-sectional view illustrating a cylindrical portion of a target holding portion in a light source device according to a first modified example of the third embodiment. FIG. [Figure 18] 10 is a cross-sectional view illustrating an example of the arrangement of sensors in a light source device 3b according to a second modification of the third embodiment. FIG. [Figure 19] 13 is a cross-sectional view illustrating an example of a debris container in a light source device according to a second modification of the third embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, a specific configuration of this embodiment will be described with reference to the drawings. The following description shows a preferred embodiment of the present disclosure, and the scope of the present disclosure is not limited to the following embodiment. In the following description, parts with the same reference numerals indicate substantially the same content.

[0025] <Embodiment 1> A light source device according to a first embodiment will be described. The light source device of this embodiment generates light such as illumination light and exposure light used in optical devices such as inspection devices and exposure devices. The light source device may be provided integrally with the optical device, or may be disposed near the optical device as a separate entity. When the optical device is an inspection device, the light source device generates illumination light that illuminates an inspection object in the inspection device. When the optical device is an exposure device, the light source device generates exposure light that exposes an exposure object in the exposure device.

[0026] The light source device generates light such as illumination light and exposure light by irradiating excitation light onto a target material held in a target holding unit. In the following embodiments, an example of a light source device will be described in which a liquid target material is held in a target holding unit including a container such as a crucible.

[0027] FIG. 1 is a cross-sectional view illustrating a light source device 1 according to embodiment 1. FIG. 2 is a plan view illustrating a target holding unit 100, a generating unit 220, and an output optical system 250 in the light source device 1 according to embodiment 1. FIG. 3 is a plan view illustrating a target holding unit 100 and an output optical system 250 in the light source device 1 according to embodiment 1. Some components are omitted in FIGS. 1 to 3 to avoid cluttering the drawings. For example, the generating unit 220 is omitted in FIG. 3. Some reference numerals may also be omitted. The same applies to the subsequent drawings.

[0028] 1 to 3, the light source device 1 includes a target holding unit 100. In addition to the target holding unit 100, the light source device 1 may further include an acquisition unit 210, a generation unit 220, a supply unit 230, a cover unit 240, an output optical system 250, and a control unit 260.

[0029] For ease of explanation of the light source device 1, an XYZ Cartesian coordinate system is introduced. For example, the rotation axis R of the target holder 100 is defined as the Z-axis direction. In this embodiment, the Z-axis direction is defined as the vertical direction, i.e., the direction of gravity. In this embodiment, the +Z-axis direction is defined as the upward direction in the direction of gravity, and the −Z-axis direction is defined as the downward direction in the direction of gravity. As described in the second embodiment, the +Z-axis direction may be defined as the downward direction in the direction of gravity, and the −Z-axis direction may be defined as the upward direction in the direction of gravity. Furthermore, the Z-axis direction may be defined as a horizontal direction perpendicular to the direction of gravity, or may be defined as a direction tilted from the direction of gravity. Here, the terms “upward” and “downward” are used not only to strictly refer to upward and downward directions in the direction of gravity, but also to include tilts due to measurement errors in measuring the upward and downward directions and manufacturing errors in the light source device 1. The upward and downward directions in this sense may also be referred to as “approximately upward” and “approximately downward.” Furthermore, the terms "upward" and "downward" are used to mean not only upward and downward in the strict sense of the gravity direction, but also when the angle between the upward direction and the strict gravity direction is small enough (for example, 15 degrees or less) that the influence of gravity can be considered equivalent in design, and when the angle between the downward direction and the strict gravity direction is small enough (for example, 15 degrees or less) that the influence of gravity can be considered equivalent in design. Upward and downward directions in this sense may be referred to as "approximately upward" and "approximately downward." Note that "approximately upward" and "approximately downward" may simply be referred to as "upward" and "downward." The above explanation may be similar for vertical, horizontal, approximately vertical, and approximately horizontal.

[0030] To avoid complicating the drawing, the main parts of the output optical system 250 are indicated by dotted lines in Fig. 2. Also, in Fig. 3, the generation unit 220 is omitted and the output optical system 250 is shown. In reality, the generation unit 220 and the output optical system 250 are arranged so as to be stacked in the Z-axis direction.

[0031] The target holder 100 holds a target material TM for generating light. The target holder 100 may include a container such as a crucible. The target holder 100 is capable of melting metal inside. The target holder 100 holds a liquid target material TM that forms a plasma PZ when irradiated with excitation light LR. The excitation light LR is, for example, laser light including IR (Infrared) light.

[0032] The target material TM is not limited to the liquid material held by the target holder 100, but may include solid materials such as tape and solid metals, as long as it is a material that forms plasma PZ when irradiated with excitation light LR. The liquid material is, for example, a molten metal such as tin (Sn) or lithium (Li), but is not limited to tin and lithium, as long as it generates plasma PZ when irradiated with excitation light LR.

[0033] The target holder 100 has a rotation axis R and rotates around the rotation axis R. For example, the target holder 100 includes a crucible that rotates around the rotation axis R. As the target holder 100 rotates around the rotation axis R, centrifugal force acts evenly on the target material TM held by the target holder 100, making it possible to make the thickness of the target material TM uniform and stabilizing the light L0 extracted from the light source device 1. The target holder 100 includes a bottom portion 110, a cylindrical portion 120, and an opposing portion 130.

[0034] The bottom portion 110 is disposed on the -Z-axis direction side of the facing portion 130. Therefore, the facing portion 130 is disposed on the +Z-axis direction side of the bottom portion 110. The bottom portion 110 and the facing portion 130 are disposed inside an area surrounded by the cylindrical portion 120. The cylindrical portion 120 is disposed so as to surround the rotation axis R. In this embodiment, the bottom portion 110 is disposed below the facing portion 130 in the direction of gravity. Therefore, the facing portion 130 is disposed above the bottom portion 110 in the direction of gravity.

[0035] The bottom portion 110 is, for example, a disk-shaped member and is connected to the cylindrical portion 120 so as to communicate with the cylindrical portion 120. Note that, as shown in Modification 2 of this embodiment, the bottom portion 110 may be an annular member. The central axis of the disk-shaped and annular bottom portion 110 may coincide with the rotation axis R. The bottom portion 110 may have a first surface 111 and a second surface 112 as opposing plate surfaces. The first surface 111 faces the +Z axis direction, and the second surface 112 faces the −Z axis direction. In this embodiment, the first surface 111 faces upward in the direction of gravity, and the second surface 112 faces downward in the direction of gravity. The opposing portion 130 is disposed so as to be in contact with the first surface 111 of the bottom portion 110. Note that the bottom portion 110 and the opposing portion 130 may be integrally formed. In that case, the opposing portion 130 is formed continuously with the first surface 111 of the bottom portion 110. In this case, the first surface 111 is a virtual surface.

[0036] The cylindrical portion 120 includes, for example, a cylindrical member. The central axis of the cylindrical portion 120 may coincide with the rotation axis R. One opening 121 of the cylindrical portion 120 faces the +Z axis direction side. The other opening 122 of the cylindrical portion 120 faces the -Z axis direction side. In this embodiment, the opening 121 faces upward, and the opening 122 faces downward. The opening 122 is connected to the bottom portion 110 so as to communicate with the bottom portion 110. Therefore, the opening 122 of the cylindrical portion 120 is closed by the bottom portion 110. For example, the bottom portion 110 is disposed inside the opening 122, and thereby the opening 122 is closed by the bottom portion 110.

[0037] In this way, the cylindrical portion 120 is open on one side and communicates with the bottom portion 110 on the other side. Specifically, the cylindrical portion 120 is open on the +Z axis direction side and communicates with the bottom portion 110 on the −Z axis direction side. In this embodiment, the opening 121 of the cylindrical portion 120 faces upward in the direction of gravity. As will be described in the second embodiment, the opening 121 of the cylindrical portion 120 may face downward in the direction of gravity. Furthermore, the opening 121 of the cylindrical portion 120 may face perpendicular to the direction of gravity or may be inclined toward the direction of gravity.

[0038] The bottom portion 110 and the cylindrical portion 120 may be formed integrally. In that case, the bottom portion 110 is formed continuous with the opening 122 of the cylindrical portion 120. The opening 122 is a virtual opening.

[0039] The portion of the cylindrical portion 120 on the opening 121 side is called the opening-side cylindrical portion 124. The portion of the cylindrical portion 120 on the bottom 110 side is called the bottom cylindrical portion 125. The portion of the cylindrical portion 120 between the opening-side cylindrical portion 124 and the bottom cylindrical portion 125 is called the main body portion 126. Therefore, the cylindrical portion 120 includes the main body portion 126, the opening-side cylindrical portion 124, and the bottom cylindrical portion 125. The opening-side cylindrical portion 124 is the portion on the +Z axis direction side of the cylindrical portion 120. The opening-side cylindrical portion 124 is located on the +Z axis direction side of the main body portion 126. The bottom cylindrical portion 125 is the portion on the -Z axis direction side of the cylindrical portion 120. The bottom cylindrical portion 125 is located on the -Z axis direction side of the main body portion 126.

[0040] The inner peripheral surface of the cylindrical portion 120 is called the inner wall 123. The inner wall 123 is formed to surround the rotation axis R. Therefore, the rotation axis R is disposed so as to be surrounded by the inner wall 123. The inner wall 123 holds a target material TM that generates a plasma PZ when irradiated with the excitation light LR.

[0041] 4 to 7 are cross-sectional views illustrating the target material TM held on the inner wall 123 of the cylindrical portion 120 of the target holder 100 in the light source device 1 according to the first embodiment. As shown in FIG. 4, the target material TM is held on the inner wall 123 of the cylindrical portion 120. The target material TM may be held on a partial region of the inner wall 123. As shown in FIG. 5, the target material TM may be held on the entire surface of the inner wall 123. As shown in FIG. 6, the inner wall 123 may have a recess formed along the inner wall 123. The recess includes, for example, a groove 127. The groove 127 may be formed along the intersection line between the inner wall 123 and a plane perpendicular to the rotation axis R. In other words, the groove 127 may include a portion formed on the inner wall 123 along the rotation direction around the rotation axis R. The groove 127 is recessed in the inner wall 123 in a direction away from the rotation axis R.

[0042] If the inner wall 123 has a groove 127, the target material TM may be held in the groove 127. By holding the target material TM in the groove 127, movement of the target material TM in the Z-axis direction can be restricted, thereby suppressing disturbance of the liquid surface of the target material TM. Furthermore, since the amount of the target material TM can be restricted within the groove 127, the amount of target material TM required can be reduced. Note that a portion of the target material TM held on the inner wall 123 may be located outside the groove 127.

[0043] As shown in FIG. 7 , the cylindrical portion 120a may have an opening-side cylindrical portion 124a, which includes a protruding portion 124b that protrudes toward the rotation axis R. The tip of the protruding portion 124b on the rotation axis R side is referred to as a tip portion 124c. In this configuration, the target material TM is held so as to be surrounded by the protruding portion 124b. That is, the groove 127 formed in the inner wall 123 may be formed by the opening-side cylindrical portion 124a protruding in the direction of the rotation axis R. In other words, the inner wall 123 may include a wall surface of the protruding portion 124b of the opening-side cylindrical portion 124a that protrudes in the direction of the rotation axis R. In this way, the inner wall 123 may include the groove 127 formed in the protruding portion 124b of the opening-side cylindrical portion 124a that protrudes in the direction of the rotation axis R.

[0044] As described above, the inner wall 123 may have a groove 127 formed along the rotation direction around the rotation axis R. The position on the target material TM irradiated with the excitation light LR is defined as the irradiation position PT. The irradiation position PT is included in the position where the target material TM is held. When the groove 127 holds the target material TM, the irradiation position PT is included in the range of the groove 127 in the Z-axis direction. A straight line perpendicular to the rotation axis R is defined as a perpendicular line. Of the perpendicular lines, a perpendicular line passing through the irradiation position PT is referred to as perpendicular line 1280 with a symbol attached. The opposing wall 133 of the opposing portion 130, which will be described later, may be located so as to intersect at least a perpendicular line passing through the end of the groove 127 in the +Z-axis direction and a perpendicular line passing through the end of the groove 127 in the -Z-axis direction.

[0045] Furthermore, in this case, the opposing wall 133 may be formed so that the distance from an intersection (denoted as P1, see FIG. 6 ) of the opposing wall 133 with a perpendicular line passing through the end of the groove 127 in the +Z-axis direction to the rotation axis R is smaller than the distance from an intersection (denoted as P2) of the opposing wall 133 with a perpendicular line passing through the end of the groove 127 in the −Z-axis direction to the rotation axis R, and further, the distance from the intersection P2 to the rotation axis R may be formed so that it is smaller than the distance D1. In this case, as described below, the opposing wall 133 may be formed so that the distance to the rotation axis R gradually decreases from the bottom end 135 to the intersection P0. In addition to this, the opposing wall 133 may be formed so that the distance to the rotation axis R gradually decreases from the intersection P2 to the intersection P1, or the opposing wall 133 may be formed so that the distance to the rotation axis R gradually decreases from the bottom end 135 to the intersection P1.

[0046] Alternatively, the irradiation position PT may be included in the range of the inner wall 123 of the target material TM in the Z-axis direction. In this case, the opposing wall 133 may be present so as to intersect at least a perpendicular line passing through the end of the inner wall 123 in the +Z-axis direction and a perpendicular line passing through the end of the inner wall 123 in the -Z-axis direction. In this case, the opposing wall 133 may be formed so that the distance from an intersection (denoted as P3, see FIG. 5 ) of the opposing wall 133 with a perpendicular line passing through the end of the inner wall 123 in the +Z-axis direction to the rotation axis R is shorter than the distance from an intersection (denoted as P4, but this may be the same as a bottom-side end 135 described below) of the opposing wall 133 with a perpendicular line passing through the end of the inner wall 123 in the -Z-axis direction to the rotation axis R, and further, the distance from the intersection P3 to the rotation axis R may be shorter than the distance D1. In this case, as described below, the distance to the rotation axis R may be gradually reduced from the intersection point P4 or the bottom side end portion 135 described below to the intersection point P0, and further, the distance to the rotation axis R may be gradually reduced from the intersection point P4 or the bottom side end portion 135 described below to the intersection point P3.

[0047] Alternatively, the irradiation position PT may be included in the range in which the target material TM is held, from the tip 124c of the protruding portion 124b of the opening-side cylindrical portion 124a to the bottom 110. In this case, the facing wall 133 may be positioned so as to intersect with a perpendicular line passing through the tip 124c of the protruding portion 124b of the opening-side cylindrical portion 124. Furthermore, the facing wall 133 may be formed so that the distance from an intersection (denoted as P5, see FIG. 7 ) of the facing wall 133 with a perpendicular line passing through the tip 124c of the protruding portion 124b of the opening-side cylindrical portion 124 to the rotation axis R is smaller than the distance D1. In this case, as described below, the facing wall 133 may be formed so that the distance to the rotation axis R gradually decreases from the bottom-side end 135 to the intersection P0. Furthermore, the facing wall 133 may be formed so that the distance to the rotation axis R gradually decreases from the bottom-side end 135 to the intersection P5.

[0048] The position in the Z-axis direction of the end of groove 127 in the -Z-axis direction may coincide with the position in the Z-axis direction of first surface 111 of bottom 110, or may be located further in the +Z-axis direction. This can be ensured even when groove 127 is formed by protruding portion 124b that protrudes in the direction of rotation axis R in opening-side cylindrical portion 124a, as described above.

[0049] The facing portion 130 includes, for example, a truncated cone-shaped member. The truncated cone-shaped facing portion 130 may have a first surface 131 and a second surface 132 as a top surface and a bottom surface facing each other in the Z-axis direction. The first surface 131 faces the +Z-axis direction. The second surface 132 faces the -Z-axis direction. In this embodiment, the first surface 131 faces upward in the direction of gravity, and the second surface 132 faces downward in the direction of gravity. The first surface 131 of the facing portion 130 is smaller than the second surface 132.

[0050] The central axis of the truncated cone-shaped facing portion 130 may coincide with the rotation axis R. The bottom portion 110 is connected to the second surface 132 of the facing portion 130. As described above, the bottom portion 110 and the facing portion 130 may be formed integrally. In that case, the second surface 132 is a virtual surface. The side surface of the facing portion 130 is called the facing wall 133.

[0051] The opposing wall 133 is surrounded by the cylindrical portion 120. The opposing wall 133 is arranged closer to the rotation axis R than the cylindrical portion 120. The opposing wall 133 faces the inner wall 123 of the cylindrical portion 120. The opposing wall 133 may be formed around the entire circumference along the rotation direction around the rotation axis R. The end of the opposing wall 133 on the opening 121 side is called the opening-side end 134. The opening-side end 134 is the end of the opposing wall 133 on the +Z-axis direction side. The end of the opposing wall 133 on the bottom 110 side is called the bottom-side end 135. The bottom-side end 135 is the end of the opposing wall 133 on the -Z-axis direction side. Therefore, the opening-side end 134 is the end opposite the bottom-side end 135.

[0052] 8 is a cross-sectional view illustrating the target material TM held on the inner wall 123 of the cylindrical portion 120 of the target holding unit 100 in the light source device 1 according to the first embodiment. The bottom end portion 135 and the cylindrical portion 120 may be in contact with each other. Alternatively, as shown in FIG. 8, the bottom end portion 135 and the cylindrical portion 120 may be spaced apart from each other. In other words, the first surface 111 of the bottom portion 110 may be exposed between the bottom end portion 135 and the cylindrical portion 120 when viewed from above.

[0053] The distance to the rotation axis R of the opposing wall 133 may gradually decrease from the bottom end 135 toward the opening end 134. The intersection of the opposing wall 133 and a perpendicular line 1280 that is perpendicular to the rotation axis R and passes through the irradiation position PT is defined as an intersection point P0. In this case, the distance to the rotation axis R of the opposing wall 133 may gradually decrease from the bottom end 135 toward the intersection point P0. In other words, a region between the intersection point P0 and the bottom end 135 of the opposing wall 133 may be included where the distance from the rotation axis R is greater than the distance D0 from the rotation axis R to the intersection point P0. Furthermore, the distance to the rotation axis R of the opposing wall 133 may gradually decrease from the intersection point P0 toward the opening end 134. In other words, a region between the intersection point P0 and the opening end 134 of the opposing wall 133 may be included where the distance from the rotation axis R is smaller than the distance D0 from the rotation axis R to the intersection point P0.

[0054] The distance to the rotation axis R of the opposing wall 133 may gradually decrease from the bottom end 135 toward the opening end 134. The distance to the rotation axis R of the opposing wall 133 may also gradually decrease from the bottom end 135 toward the vicinity of the opening end 134. The opening end 134 may have a protruding portion 134g described in Modification 1, and the vicinity of the opening end 134 may be a position on the opposing wall 133 where the protruding portion 134g protrudes from the opposing wall 133.

[0055] In this embodiment, the opening-side end 134 is the upper end of the opposing wall 133 in the direction of gravity. The bottom-side end 135 is the lower end of the opposing wall 133 in the direction of gravity. As shown in FIGS. 1 and 4 to 8, the distance D1 from the rotation axis R to the bottom-side end 135 is greater than the distance D2 from the rotation axis R to the opening-side end. Furthermore, the distance D1 from the rotation axis R to the bottom-side end 135 is greater than the distance D0 from the rotation axis R to the intersection point P0.

[0056] As mentioned above, the position on the target material TM where the excitation light LR irradiates the target material TM is called the irradiation position PT. The facing wall 133 intersects with the normal 128 to the surface of the target material TM at the irradiation position PT. When the target holder 100 is rotating at high speed, the normal 128 and the perpendicular line 1280 may be the same. In that case, the normal 128 intersects with the intersection point P0. When the excitation light LR irradiates the target material TM, debris scatters from the irradiation position PT of the target material TM. Even if the excitation light LR is incident on the surface of the target material TM at an oblique angle, the debris scatters around the direction of the normal 128 to the surface of the target material TM at the irradiation position PT. Therefore, by arranging the facing wall 133 so that it intersects with the normal 128, the debris can be caught by the facing wall 133, and the scattering of debris into the light source device 1 can be suppressed.

[0057] The distance D3 from the bottom 110 to the opening-side end 134 may be greater than the distance D4 from the bottom 110 to the irradiation position PT. This configuration increases the area of ​​the opposing wall 133 that receives debris, further preventing debris from scattering into the light source device 1. The distance D3 from the bottom 110 to the opening-side end 134 may be greater than the distance D5 from the bottom 110 to the opening-side cylindrical portion 124. This increases the area of ​​the opposing wall 133 that receives debris, further preventing debris from scattering into the light source device 1, and more effectively enables refilling by a method of bringing a target material TM into contact with the opposing wall 133, as described below. Furthermore, the relationship of distance D3 > distance D4 can be ensured.

[0058] The space between the open-side end 134 and the open-side cylindrical portion 124 is referred to as an irradiation space 136. The excitation light LR passes through the irradiation space 136 and irradiates the irradiation position PT of the target material TM. The target material TM may also be supplied to the target holding unit 100 through the irradiation space 136. Supplying the target material TM to the target holding unit 100 is referred to as refilling. The facing wall 133 may be set to a temperature equal to or higher than the melting point of the target material TM. The facing wall 133 may be heated to a temperature equal to or higher than the melting point of the target material TM by radiant heat from the inner wall 123 and the target material TM held by the inner wall 123, or may be heated to a temperature equal to or higher than the melting point of the target material TM by a temperature adjustment mechanism such as a heater provided in the facing unit 130. The target material TM may be refilled by bringing the target material TM into contact with the facing wall 133.

[0059] The irradiation space 136 may be formed along the rotation direction around the rotation axis R over the entire circumference.

[0060] FIG. 9 is a plan view illustrating a target holding unit 100g of a light source device 1g according to Modification 1 of Embodiment 1, as viewed from the Z-axis direction. FIG. 10 is a cross-sectional view illustrating a target holding unit 100g of a light source device 1g according to Modification 1 of Embodiment 1. In FIG. 9, the cover unit 240 is omitted. As shown in FIGS. 9 and 10, in the target holding unit 100g of Modification 1, the opening-side end 134 of the facing part 130g has a protrusion 134g that protrudes in a direction away from the rotation axis R. The protrusion 134g may cover the irradiation space 136. The protrusion 134g has a slit 137 that penetrates in the Z-axis direction. The protrusion 134g may have multiple slits 137. A portion of the irradiation space 136 is exposed to the slit 137.

[0061] In this way, the open-side end 134 has one or more slits 137 whose distance to the rotation axis R is greater than the distance D0 from the intersection P0 to the rotation axis R, which are formed along the entire circumference in the direction of rotation around the rotation axis R, and which are arranged along the direction of rotation around the rotation axis R so as to expose a portion of the irradiation space 136. With this configuration, the open-side end 134 rotates in conjunction with the rotation of the target holder 100g, and the excitation light LR can be irradiated through the slits 137. The generation unit 220 may irradiate the excitation light LR in synchronization with the rotation of the slits 137.

[0062] 11 is a cross-sectional view illustrating a target holding unit 100h of a light source device 1h according to Modification 2 of Embodiment 1. As shown in FIG. 11, in the target holding unit 100h of Modification 2, the facing unit 130h may have a hollowed-out interior, i.e., may include a hollow space inside. In this case, the facing unit 130h has a second surface 132 on its inner surface. The facing unit 130h has the same configuration as the facing unit 130 described above, except that the interior is hollow and the inner surface has the second surface 132.

[0063] As shown in FIG. 1 , the acquisition unit 210 acquires information about the inner wall 123 of the target holding unit 100. The information about the inner wall 123 is referred to as status information. The acquisition unit 210 also acquires information about bright spot positions of the plasma PZ. The information about the bright spot positions is referred to as bright spot information. The acquisition unit 210 may include a sensor 211 and a processing unit 212. The sensor 211 may include a camera or a position sensor. The camera may capture still images or video. The sensor 211 and the processing unit 212 are connected via a communication line, including wired and wireless, so that information can be transmitted between them. The acquisition unit 210 may include one sensor 211 or multiple sensors 211. The acquisition unit 210 may acquire the status information and the bright spot information using the same sensor 211. The acquisition unit 210 may also acquire the status information and the bright spot information using different sensors 211.

[0064] The acquisition unit 210 may acquire image information of the inner wall 123 captured by a camera as status information of the inner wall 123 of the target holding unit 100. The acquisition unit 210 may acquire the amount of the target material TM based on the area of ​​the inner wall 123 occupied by the target material TM in the acquired status information (i.e., identified based on the status information). The processing unit 212 acquires the amount of the target material TM based on at least one of the width and area of ​​the area of ​​the inner wall 123 occupied by the target material TM in the image information. The width and area of ​​the area of ​​the inner wall 123 occupied by the target material TM may be acquired based on the area of ​​the portion identified as the target material TM in the captured image.

[0065] The acquisition unit 210 may acquire the irradiation position PT based on the acquired bright spot information. For example, the sensor 211 may be disposed at a position where it detects light L0 generated from the plasma PZ that passes near the end of the opening-side cylindrical portion 124 and at a position where it detects light L0 that passes near the opening-side end 134. With such an arrangement, when the light L0 generated from the plasma PZ reaches the sensor 211, the bright spot position is located at a predetermined position, and when the light L0 generated from the plasma PZ is blocked by the opening-side cylindrical portion 124 or the opening-side end 134 and does not reach the sensor 211, it can be determined that the bright spot position is deviated from the predetermined position.

[0066] The acquisition unit 210 may predict the amount of target material TM based on the area of ​​the inner wall 123 occupied by the target material TM in the acquired status information (i.e., identified based on the status information). That is, the acquisition unit 210 may acquire the predicted amount of target material TM. For example, the acquisition unit 210 acquires supply information, in which the supply unit 230 supplies the target material TM, directly from the supply unit 230 or indirectly via the control unit 260 or the like. The acquisition unit 210 may predict the amount of target material TM based on the supply information and the status information.

[0067] Furthermore, the acquisition unit 210 may predict the bright spot position and the irradiation position PT based on the bright spot position in the acquired bright spot information (i.e., identified based on the bright spot information). That is, the acquisition unit 210 may acquire the predicted bright spot position and irradiation position PT. For example, the acquisition unit 210 acquires supply information in which the supply unit 230 supplies the target material TM directly from the supply unit 230 or indirectly via the control unit 260 or the like. The acquisition unit 210 may predict the bright spot position and the irradiation position PT based on the supply information and the bright spot information.

[0068] The acquisition unit 210 may acquire the status information and bright spot information from detection means other than a camera, such as a position sensor. For example, the acquisition unit 210 may acquire the status information and bright spot information from the position of the target material TM detected by a position sensor. The position sensor detects the position of the end of the target material TM. As a result, the position sensor may detect at least one of the width and area of ​​the region where the target material TM occupies the inner wall 123. Furthermore, the position sensor may detect the position where the plasma PZ is generated and the irradiation position PT from the position of the bright spot of the plasma PT.

[0069] The position sensor may include, for example, a displacement meter, a high-speed camera, a low-speed camera, a segmented PD (Photo Diode), or a TDI (Time Delay Integration) camera. The position sensor may measure the surface position in one dimension, two dimensions, or three dimensions, or a combination of these. Thus, the acquisition unit 210 may include a displacement meter that outputs the amount of displacement of the surface position of the target material TM covering the inner wall 123. The acquisition unit 210 acquires the amount of the target material TM and the bright spot position based on the image information and the amount of displacement.

[0070] The acquisition unit 210 may also use a camera and a position sensor, etc. in combination. The acquisition unit 210 may use one of the camera and the position sensor, etc., to supplement the other. For example, the state information acquired by one of the camera and the position sensor, etc., may be corrected by the other. The acquisition unit 210 may combine the image information acquired from the camera with the position sensor, etc., to acquire or predict the amount of the target material TM, the bright spot position, and the irradiation position PT.

[0071] As shown in FIG. 2, the generation unit 220 includes an optical member 221 and an optical path cover 222. The optical path cover 222 may be referred to as an optical path cone. The optical member 221 and the optical path cover 222 may be disposed on the +Z-axis direction side of the target holder 100. The optical member 221 focuses the excitation light LR on the target material TM. The optical member 221 may include a focusing lens, a mirror, and the like. The generation unit 220 excites the target material TM, for example, by focusing laser light as the excitation light LR on the target material TM. The generation unit 220 irradiates the target material TM with the excitation light LR so that it has a component in the -Z-axis direction. In this embodiment, the generation unit 220 irradiates the target material TM with the excitation light LR so that it has a downward component in the direction of gravity.

[0072] The generation unit 220 forms a plasma PZ from the target material TM. When the plasma PZ is formed, EUV light LE is generated from the plasma PZ. For example, the EUV light LE is used as light L0 for illumination, exposure, etc. in an optical device such as an inspection device or an exposure device.

[0073] Note that the optical member 221 in the generation unit 220 is not limited to a condenser lens and a mirror, and may include a laser device that generates the excitation light LR, as long as it is a member that irradiates the target material TM with the excitation light LR. That is, the light source device 1 may include a laser device that generates the excitation light LR. On the other hand, the light source device 1 may introduce the excitation light LR from a laser device that is installed outside the light source device 1 and separate from the light source device 1 into the light source device 1. The excitation light LR may be irradiated onto the target material TM by the control unit 260 controlling the oscillation and stopping.

[0074] The light path cover 222 has a cylindrical shape with one open end 223 and the other open end 224. The light path cover 222 covers the light path of the excitation light LR. For example, the one end 223 is the end on the −Z axis direction side of the light path cover 222, and the other end 224 is the end on the +Z axis direction side of the light path cover 222. The light path cover 222 is cylindrical, for example, with the opening diameter of the other end 224 being larger than the opening diameter of the one end 223. Specifically, the light path cover 222 has a cone-shaped or truncated conical portion with a hollow interior.

[0075] Note that optical path cover 222 may include a portion whose diameter does not gradually increase from the opening at one end 223 toward the opening at the other end 224. Specifically, optical path cover 222 may include a portion other than a cone shape or a truncated cone shape as long as it is a cylindrical shape having open one end 223 and open other end 224, and the opening diameter at one end 223 is larger than the opening diameter at the other end 224.

[0076] One end 223 of the light path cover 222 faces the target material TM. One end 223 of the light path cover 222 is connected to the cover unit 240. Note that one end 223 of the light path cover 222 may pass through the cover unit 240. The other end 224 of the light path cover 222 is arranged on the +Z axis direction side of the cover unit 240. In this manner, the light path cover 222 may be attached to the cover unit 240. In this embodiment, the light path cover 222 is arranged above the target holding unit 100 in the direction of gravity. One end 223 faces downward in the direction of gravity, and the other end 224 faces upward. As will be described later, the light path cover 222 may be divided into multiple parts.

[0077] The optical path cover 222 may or may not include an optical member 221 inside. The optical member 221 may be arranged on the other end 224 side inside the optical path cover 222, or may be arranged between the one end 223 and the other end 224. The optical path cover 222 may have an opening in a portion through which the excitation light LR passes, or a transparent member that transmits the excitation light LR may be fitted into the portion through which the excitation light LR passes.

[0078] The optical path cover 222 may include a temperature adjustment mechanism such as a heater. The temperature of the optical path cover 222 may be adjusted to a temperature equal to or higher than the melting point of the target material TM by the temperature adjustment mechanism. This may melt debris adhering to the optical path cover 222 and return it to the target holding unit 100.

[0079] The supply unit 230 supplies the target material TM to the target holding unit 100. The supply unit 230 may supply a solid target material TM to the target holding unit 100. The solid target material TM may be linear. The linear target material TM may be wound around a bobbin or the like and held therein. The supply unit 230 supplies the linear target material TM from the bobbin into the target holding unit 100.

[0080] The supply unit 230 may supply the molten target material TM to the inner wall 123. The supply unit 230 may supply the molten target material TM to the inner wall 123 using the facing wall 133. The supply unit 230 may melt the solid target material TMa by bringing it into contact with the facing wall 133, and supply it into the target holding unit 100. The target material TM melted by the facing wall 133 reaches the inner wall 123 by centrifugal force. This eliminates the need to bring the solid target material TM into contact with the target material TM on the inner wall 123, thereby preventing a decrease in the temperature of the target material TM on the inner wall 123. Furthermore, it is possible to prevent the surface condition of the target material TM from being disturbed by vibrations, etc.

[0081] The cover part 240 is arranged to cover the target holding part 100. For example, the cover part 240 covers the opening 121 on the +Z-axis direction side of the target holding part 100. In this embodiment, the cover part 240 covers the upper side of the opening 121 in the direction of gravity. The cover part 240 has an opening for inputting the excitation light LR and an opening for extracting the EUV light LE.

[0082] The cover portion 240 prevents debris that scatters with the formation of the plasma PZ from scattering into the light source device 1. The cover portion 240 may be adjusted to a temperature equal to or higher than the melting point of the target material TM. This allows debris adhering to the cover portion 240 to be remelted and reused as the target material TM.

[0083] 3, the output optical system 250 extracts light L0 generated by irradiating the target material TM with excitation light LR from the light source device 1. The output optical system 250 includes, for example, an optical member 251 and a light path cover 252. The optical member 251 includes, for example, a collector mirror. Note that the optical member 251 is not limited to a collector mirror as long as it is an optical member that extracts light L0 generated by irradiating the target material TM with excitation light LR, and may be a second collector mirror (not shown) that further reflects the light L0 reflected by the collector mirror.

[0084] The optical member 251 reflects the light L0 generated from the target material TM by irradiation with the excitation light LR. The optical member 251, for example, reflects the EUV light LE generated by irradiation with the excitation light LR. That is, the light L0 may include the EUV light LE. The EUV light LE is generated from the plasma PZ formed by irradiating the target material TM with the excitation light LR. The EUV light LE generated from the plasma PZ and reflected by the optical member 251 is emitted to at least one of an inspection tool and an exposure tool for use as illumination or exposure.

[0085] The light path cover 252 has a cylindrical shape with an open one end 253 and an open other end 254. The light path cover 252 covers the optical path of the light L0 generated from the plasma PZ. The light path cover 252 is, for example, cylindrical in shape with an opening diameter at the one end 253 being larger than the opening diameter at the other end 254. Specifically, the light path cover 252 has a cone-shaped or a hollow truncated cone-shaped portion. Note that the light path cover 252 may include a portion whose diameter does not gradually increase from the opening at the one end 253 toward the opening at the other end 254. Specifically, the light path cover 252 may include a portion other than a cone-shaped or truncated cone-shaped portion as long as it is cylindrical in shape with an open one end 253 and an open other end 254 and the opening diameter at the other end 254 being larger than the opening diameter at the one end 253.

[0086] One end 253 of the light path cover 252 faces the target material TM. One end 253 of the light path cover 252 may penetrate the cover unit 240. The other end 254 of the light path cover 252 is disposed on the +Z axis direction side of the cover unit 240. In this manner, the light path cover 252 may be attached to the cover unit 240. The light path cover 252 may or may not include an optical member 251 therein. For example, the optical member 251 may be disposed on the other end 254 side inside the light path cover 252, or may be disposed between the one end 253 and the other end 254. Note that the light path cover 252 may have an opening in a portion through which the light L0 passes, or a transparent member that transmits the light L0 may be fitted into the portion through which the light L0 passes. Furthermore, as will be described later, the light path cover 252 may be divided into multiple sections.

[0087] The control unit 260 may control each component in the light source device 1. The control unit 260 is connected to each component in the light source device 1 in a state in which information can be transmitted via a communication line, including wireless or wired lines. The control unit 260 analyzes, for example, the status information and bright spot information acquired by the acquisition unit 210. The control unit 260 also analyzes output information including the intensity and irradiation position of the light L0, such as illumination light, output by the output optical system 250.

[0088] The control unit 260 controls the formation state of the plasma PZ, including the intensity and irradiation position PT of the excitation light LR in the generation unit 220, based on the state information, bright spot information, output information of the light L0 such as illumination light, etc. Furthermore, the control unit 260 controls the supply state, including the temperature and supply amount of the target material TM in the supply unit 230, based on the state information, bright spot information, output information, etc. Furthermore, the control unit 260 controls the temperature and other parameters of the cover unit 240, based on the state information, bright spot information, output information, etc.

[0089] Next, the effects of this embodiment will be described. In the light source device 1 of this embodiment, the target holding unit 100 has an opposing wall 133. The opposing wall 133 intersects with a normal 128 to the surface of the target material TM at the irradiation position PT, and therefore can prevent debris generated from the irradiation position PT from scattering inside the light source device 1. Furthermore, the opposing wall 133 intersects with a perpendicular line 1280 that is orthogonal to the rotation axis R and passes through the irradiation position PT, and therefore can prevent debris generated from the irradiation position PT from scattering inside the light source device 1.

[0090] Furthermore, the distance D1 from the rotation axis R to the bottom end 135 of the opposing wall 133 is greater than the distance D2 from the rotation axis R to the opening end 134 of the opposing wall 133, and is also greater than the distance D0 from the rotation axis R to the intersection point P0 of the opposing wall 133. Therefore, debris scattered on the opposing wall 133 can be returned to the inner wall 123 by centrifugal force. Furthermore, an irradiation space 136 can be formed, and the excitation light LR can pass through the irradiation space 136 and irradiate the irradiation position PT. Furthermore, the target material TM can be refilled through the irradiation space 136. Between the intersection point P0 and the opening end 134 of the opposing wall 133, a region is included where the distance from the rotation axis R is smaller than the distance from the rotation axis R to the intersection point P0. Furthermore, the distance of the opposing wall 133 to the rotation axis R gradually decreases from the bottom end 135 to the opening end 134. With this configuration, debris scattered onto the opposing wall 133 can be returned to the inner wall 123 more smoothly by centrifugal force.

[0091] By making the distance D3 from the bottom 110 to the opening-side end 134 greater than the distance from the bottom 110 to the irradiation position PT, it is possible to further improve the capture of debris by the facing wall 133. By making the distance D3 from the bottom 110 to the opening-side end 134 greater than the distance D5 from the bottom 110 to the opening-side cylindrical portion 124, it is possible to further improve the capture of debris by the facing wall 133 and also make it possible to more smoothly refill the target material TM from the facing wall 133.

[0092] <Embodiment 2> Next, a light source device 2 of embodiment 2 will be described. In the light source device 2 of this embodiment, the configuration of the light source device 1 of embodiment 1 is reversed in the direction of gravity. FIG. 12 is a cross-sectional view illustrating the light source device 2 according to embodiment 2. As shown in FIG. 12, the upward and downward directions of each component of the light source device 2 in the direction of gravity are reversed compared to the light source device 1 of embodiment 1. That is, in this embodiment, the +Z axis direction is downward in the direction of gravity, and the −Z axis direction is upward in the direction of gravity. Therefore, the arrangement position of each component of the light source device 2 in the XYZ Cartesian coordinate system is the same as that of the light source device 1 of embodiment 1. However, the upward and downward directions in the direction of gravity are reversed.

[0093] For example, with regard to the bottom portion 110, in this embodiment, the bottom portion 110 is disposed on the −Z axis direction side of the facing portion 130, similar to the first embodiment. However, in the first embodiment, the bottom portion 110 is disposed below the facing portion 130 in the direction of gravity, whereas in this embodiment, the bottom portion 110 is disposed above the facing portion 130. Also, in this embodiment, the first surface 111 faces toward the +Z axis direction and the second surface 112 faces toward the −Z axis direction, similar to the first embodiment. However, in the first embodiment, the first surface 111 faces upward in the direction of gravity and the second surface 112 faces downward, whereas in this embodiment, the first surface 111 faces downward in the direction of gravity and the second surface 112 faces upward.

[0094] Furthermore, for example, with regard to cylindrical portion 120, in this embodiment, opening 121 of cylindrical portion 120 faces in the +Z-axis direction, similar to embodiment 1. However, whereas in embodiment 1 opening 121 of cylindrical portion 120 faces upward in the direction of gravity, in this embodiment opening 121 of cylindrical portion 120 faces downward in the direction of gravity.

[0095] Furthermore, for example, with regard to the facing portion 130, in this embodiment, the first surface 131 of the facing portion 130 faces the +Z axis direction side, and the second surface 132 faces the −Z axis direction side, as in embodiment 1. However, while in embodiment 1 the first surface 131 faces upward in the direction of gravity and the second surface 132 faces downward, in this embodiment the first surface 131 faces downward in the direction of gravity and the second surface 132 faces upward.

[0096] The positions of the components of the light source device 2 other than the target holder 100 in the XYZ Cartesian coordinate system are the same as those of the light source device 1 of the first embodiment, but the upward and downward directions in the direction of gravity are reversed.

[0097] In the above-described first embodiment, scattered debris may return to the target holder 100. For example, debris adhering to components such as the facing portion 130, the cover portion 240, the optical path cover 222, and the optical path cover 252, as well as debris scattered into the space above the target holder 100 in the direction of gravity, may return to the target holder 100 due to gravity. This may have adverse effects, such as vibrations, on the liquid surface of the target material TM held in the target holder 100.

[0098] According to this embodiment, the scattered debris falls due to gravity below the target holding part 100 in the direction of gravity. This makes it possible to prevent the scattered debris from returning to the target holding part 100. Other configurations and effects are included in the description of the first embodiment.

[0099] <Variation 1> FIG. 13 is a cross-sectional view illustrating the cylindrical portion 120a of the target holder 100a in a light source device 2a according to Modification 1 of Embodiment 2. As shown in FIG. 13, in the light source device 2a according to this modification, the cylindrical portion 120a of the target holder 100a includes an opening-side cylindrical portion 124a. The opening-side cylindrical portion 124a includes a protruding portion 124b that protrudes toward the rotation axis R beyond the main body portion 126. Therefore, since the opening-side cylindrical portion 124a protrudes toward the rotation axis R, a distance D6 from the rotation axis R to the opening-side cylindrical portion 124a is smaller than a distance D7 from the rotation axis R to the inner wall 123. Note that if the groove 127 is not formed in the inner wall 123, the distance D7 from the rotation axis R to the inner wall 123 may be the same as a distance D1 from the rotation axis R to the bottom-side end 135.

[0100] As described above, it may be considered that the opening-side cylindrical portion 124a protrudes in the direction of the rotation axis R, thereby forming the groove 127 in the inner wall 123. In this case, it may be considered that the groove 127 is formed in the region in the −Z-axis direction from the Z-axis direction position of the tip end portion 124c.

[0101] When the opening 121 of the cylindrical portion 120 faces downward in the direction of gravity, the opening-side cylindrical portion 124a may have a groove 129 recessed downward in the direction of gravity. When the centrifugal force acting on the target material TM due to the rotation of the target holder 100 becomes smaller than the gravity acting on the target material TM, the groove 129 can hold the target material TM. This makes it possible to prevent the target material TM from falling and being lost. Other configurations and effects are included in the description of the first and second embodiments.

[0102] <Variation 2> 14 is a cross-sectional view illustrating the arrangement of sensor 211 in light source device 2b according to Modification 2 of Embodiment 2. As shown in Fig. 14, light L0 from plasma PZ generated at irradiation position PT is extracted from light source device 2b by optical member 251 in output optical system 250. In this modification, sensor 211 is disposed at least one of a position where light L0 passing near an end (e.g., tip portion 124c) of opening-side cylindrical portion 124a is detected and a position where light L0 passing near opening-side end 134 is detected.

[0103] With this arrangement, when light L0 generated from plasma PZ reaches sensor 211, the bright spot position is located at a predetermined position, and when light L0 generated from plasma PZ is blocked by opening-side cylindrical portion 124a (e.g., tip portion 124c) or opening-side end 134 and does not reach sensor 211, it can be determined that the bright spot position is shifted from the predetermined position. Therefore, the sensitivity for detecting a shift in irradiation position PT can be improved.

[0104] 14, light source device 2b includes target holder 100a having cylindrical portion 120a including opening-side cylindrical portion 124a. However, light source device 2b may also include target holder 100 having cylindrical portion 120 including opening-side cylindrical portion 124 that does not protrude in the direction of rotation axis R. In that case, sensor 211 is disposed at a position where it detects light L0 passing near the end of opening-side cylindrical portion 124. Other configurations and effects are included in the descriptions of Embodiments 1 and 2 and Modification 1.

[0105] <Variation 3> FIG. 15 is a cross-sectional view illustrating the debris collection container 242 in a light source device 2c according to Modification 2 of Embodiment 2. FIG. 15 shows cross sections of the target holder 100a and the debris collection container 242, and a side view of the light path cover 222. As shown in FIG. 15, the light source device 2c of this modification includes the debris collection container 242 instead of or in addition to the cover 240. The debris collection container 242 is bucket-shaped and can contain scattered debris. As described below, it can also contain a target material TMb where debris has gathered. In this way, when the opening 121 of the cylindrical portion 120a faces downward in the direction of gravity, the light source device 2c may further include a debris collection container 242 that covers the opening-side cylindrical portion 124a from below. Note that in FIG. 15, the light source device 2c includes a target holder 100a having a cylindrical portion 120a that includes the opening-side cylindrical portion 124a. However, the light source device 2c may include a target holder 100 having a cylindrical portion 120 including an opening-side cylindrical portion 124 that does not protrude in the direction of the rotation axis R.

[0106] At least one of the optical path cover 222 and the optical path cover 252 may be disposed inside the debris container 242. At least one of the optical path cover 222 and the optical path cover 252 may also be disposed between the cylindrical section 120 and the debris container 242. That is, the optical path cover 222, the optical path cover 252, etc. may be attached to the cover section 240, disposed inside the debris container 242, or disposed between the cylindrical section 120 and the debris container 242. In FIG. 15 , only the optical path cover 222 is shown. At least one of the optical path cover 222 and the optical path cover 252 may be divided into multiple sections. The following description will be given using the optical path cover 222 as an example. The multiple sections include, for example, section 222a and section 222b. A gap is formed between section 222a and section 222b. The optical path cover 222 may include a temperature adjustment mechanism such as a heater. Debris scattered from the irradiation position PT on the target material TM penetrates the inside of the optical path cover 222, etc., and adheres to the inner surface of the optical path cover 222, etc. Furthermore, debris scattered from the irradiation position PT adheres to the outer surface of the optical path cover 222. Such debris adhering to the optical path cover 222 is melted by the temperature adjustment mechanism, conveyed to the lower end of the portion 222a in the direction of gravity, and falls from the lower end of the portion 222a. This allows the debris to be collected in a predetermined location and recovered as target material TMb.

[0107] The method for melting debris adhering to the light path cover 222 is not limited to the temperature adjustment mechanism. For example, the optical axis of the excitation light LR passing through the light path cover 222 may be shifted and the light path cover 222 may be irradiated with the excitation light LR to melt the debris adhering to the light path cover 222. Other configurations and effects are included in the descriptions of the first and second embodiments and the respective modified examples.

[0108] <Embodiment 3> FIG. 16 is a cross-sectional view illustrating a light source device 3 according to a third embodiment. As shown in FIG. 16, the light source device 3 of this embodiment includes a target holding part 100d. The target holding part 100d does not have an opposing part 130. The target holding part 100d includes a bottom part 110 and a cylindrical part 120. The cylindrical part 120 has one opening 121 and the other opening 122 that communicates with the bottom part 110. An inner wall 123 of the cylindrical part 120 holds a target material TM that generates a plasma PZ when irradiated with excitation light LR. The opening of the cylindrical part 120 faces downward in the direction of gravity.

[0109] As described above, the configuration of the light source device 3 of this embodiment is the same as that of the light source device 2 of the second embodiment, except that it does not have the facing portion 130 of the light source device 2 of the second embodiment. In the light source device 2 of the second embodiment, scattered debris falls due to gravity, and therefore, it is possible to prevent the debris from returning to the inner wall 123. In the light source device 2 of the second embodiment, debris adhering to the facing portion 130 is returned from the facing wall 133 to the inner wall 123 by centrifugal force, but the light source device 3 of this embodiment does not have the facing portion 130, and therefore does not return the debris from the facing wall 133 to the inner wall 123. Depending on the balance between the influence of fluctuations in the liquid level that may occur when the target material TM flows down the facing wall 133 and returns to the inner wall 123 and the consumption rate of the target material TM, the light source device 3 of the third embodiment has an advantage. Other configurations and effects are included in the descriptions of the first and second embodiments and their respective modifications.

[0110] <Variation 1> FIG. 17 is a cross-sectional view illustrating the cylindrical portion 120a of the target holder 100e in a light source device 3a according to Modification 1 of Embodiment 3. As shown in FIG. 17, in the light source device 3a according to this modification, the cylindrical portion 120a of the target holder 100e includes an opening-side cylindrical portion 124a. In this modification, the distance D6 from the rotation axis R to the opening-side cylindrical portion 124a is also smaller than the distance D7 from the rotation axis R to the inner wall 123. Furthermore, when the opening 121 of the cylindrical portion 120 faces downward in the direction of gravity, the opening-side cylindrical portion 124a may have a groove 129 recessed downward. The configuration of the light source device 3a according to this modification is the same as that of the light source device 2a according to Modification 1 of Embodiment 2, except that the light source device 3a does not have the facing portion 130 of the light source device 2a according to Modification 1 of Embodiment 2. Other configurations and effects are included in the descriptions of Embodiments 1 to 3 and their respective modifications.

[0111] <Variation 2> 18 is a cross-sectional view illustrating the arrangement of sensor 211 in light source device 3b according to Modification 2 of Embodiment 3. As shown in Fig. 18, light L0 from plasma PZ generated at irradiation position PT is extracted from light source device 3b by optical member 251 in output optical system 250. In this modification, sensor 211 is disposed at a position where it detects light L0 passing near the end of opening-side cylindrical portion 124a.

[0112] With this arrangement, when light L0 generated from plasma PZ reaches sensor 211, the bright spot position is located at a predetermined position, and when light L0 generated from plasma PZ is blocked by opening-side cylindrical portion 124a and does not reach sensor 211, it can be determined that the bright spot position is shifted from the predetermined position. Therefore, it is possible to improve the sensitivity for detecting the shift in irradiation position PT.

[0113] 18, light source device 3b includes target holder 100e having cylindrical portion 120a including opening-side cylindrical portion 124a. However, light source device 3b may also include target holder 100d having cylindrical portion 120 including opening-side cylindrical portion 124 that does not protrude in the direction of rotation axis R. In that case, sensor 211 is disposed at a position where it detects light L0 passing near the end of opening-side cylindrical portion 124. The configuration of light source device 3b of this modification is the same as light source device 2b of modification 2 of embodiment 2, except that it does not include facing portion 130. Other configurations and effects are included in the descriptions of embodiments 1 to 3 and their modifications.

[0114] <Variation 3> FIG. 19 is a cross-sectional view illustrating the debris container 242 in a light source device 3c according to Modification 2 of Embodiment 3. FIG. 19 shows cross sections of the target holder 100e and the debris container 242, and a side view of the light path cover 222. As shown in FIG. 19, the light source device 3c of this modification includes the debris container 242 instead of or in addition to the cover 240. In this way, when the opening 121 of the cylindrical portion 120a faces downward in the direction of gravity, the light source device 3c may further include a debris container 242 that covers the opening-side cylindrical portion 124a from below. Note that in FIG. 19, the light source device 3c includes a target holder 100e having a cylindrical portion 120a that includes the opening-side cylindrical portion 124a. However, the light source device 3c may also include a target holder 100d having a cylindrical portion 120 that includes an opening-side cylindrical portion 124 that does not protrude in the direction of the rotation axis R. The configuration of the light source device 3c of this modification is the same as that of the light source device 2c of Modification 3 of Embodiment 2, except that it does not have the opposing portion 130. Other configurations and effects are included in the descriptions of Embodiments 1 to 3 and each modification.

[0115] In the second and third embodiments, the opening 121 of the cylindrical portion 120 faces downward in the direction of gravity. However, as a further modification, the opening 121 of the cylindrical portion 120 may face horizontally, perpendicular to the direction of gravity. It may also face in a direction tilted from the direction of gravity. The above describes the embodiments of the present disclosure, but the present disclosure includes appropriate modifications that do not impair the object and advantages thereof, and is not limited to the above-described embodiments. Furthermore, the configurations of the first to third embodiments and the modifications may be combined as appropriate. Furthermore, the light source devices described below are also within the scope of the technical concept of the embodiments.

[0116] (Appendix A1) A target holder is provided, The target holder is The bottom and a cylindrical portion having an open end and the other end communicating with the bottom portion; Including, an inner wall of the cylindrical portion holds a target material that generates plasma when irradiated with excitation light; The opening of the cylindrical portion faces substantially downward in the direction of gravity. Light source device. (Appendix A2) the cylindrical portion includes an opening-side cylindrical portion at an opening side and a bottom-side cylindrical portion at a bottom side, a distance from a rotation axis surrounded by the cylindrical portion to the opening-side cylindrical portion is shorter than a distance from the rotation axis to the inner wall; 10. A light source device according to claim A1. (Appendix A3) the opening-side cylindrical portion has the groove recessed downward in the gravity direction, 1. A light source device as described in Appendix A2. (Appendix A4) a sensor disposed at a position to detect light passing near an end of the opening-side cylindrical portion, out of light generated from the plasma; 1. A light source device according to claim A2 or A3. (Appendix A5) Further provided with a cover part or debris container that covers the opening side cylindrical part from below, 1. A light source device according to claim A2 or A3. (Appendix A6) a light path cover for covering a light path of at least one of the excitation light and the light generated from the plasma, The optical path cover is at least one of attached to the cover part, disposed inside the debris container, and disposed between the cylindrical part and the debris container. 1. A light source device as described in Appendix A5. (Appendix A7) the light path cover includes a plurality of portions; 1. A light source device as described in Appendix A6. (Appendix B1) A target holder is provided, The target holder is The bottom and a cylindrical portion having an open end and the other end communicating with the bottom portion; Including, an inner wall of the cylindrical portion holds a target material that generates plasma when irradiated with excitation light; The opening of the cylindrical portion is oriented substantially perpendicular to the direction of gravity. Light source device. (Appendix B2) the cylindrical portion includes an opening-side cylindrical portion at an opening side and a bottom-side cylindrical portion at a bottom side, a distance from a rotation axis surrounded by the cylindrical portion to the opening-side cylindrical portion is shorter than a distance from the rotation axis to the inner wall; 10. A light source device according to claim B1. (Appendix B3) a sensor disposed at a position to detect light passing near an end of the opening-side cylindrical portion, out of light generated from the plasma; 1. A light source device according to claim B1 or B2. (Appendix B4) Further comprising a debris container provided below the cylindrical portion in the direction of gravity, 1. A light source device according to claim xB1 or B2. (Appendix B5) a light path cover for covering a light path of at least one of the excitation light and the light generated from the plasma, The optical path cover is disposed above the debris container. 1. A light source device according to claim B1 or B2. (Appendix B6) the light path cover includes a plurality of portions; 1. A light source device as described in Appendix B5. [Explanation of symbols]

[0117] 1, 1g, 1h, 2, 2a, 2b, 2c, 3, 3a, 3b, 3c light source device 100, 100a, 100d, 100e, 100g, 100h target holder 110 Bottom 111 Page 1 112 Side 2 120, 120a cylindrical part 121 Aperture 122 Aperture 123 Interior wall 124, 124a Opening side cylindrical portion 124b Projecting part 124c Tip 125 Bottom cylindrical part 126 Main body 127 Groove 128 normals 129 Groove 130, 130g, 130h Opposite part 131 Page 1 132 2nd page 133 Opposite wall 134 Opening end 134g protrusion 135 Bottom side edge 136 Irradiation Space 137 Slit 210 Acquisition Department 211 Sensor 212 Processing section 220 Generation part 221 Optical Components 222 Optical path cover 222a, 222b parts 223 one end 224 other end 230 Supply section 240 Cover 242 Debris Container 250 output optical system 251 Optical Components 252 Optical path cover 253 one end 254 other end 260 Control Unit 1280 Perpendicular D0, D1, D2, D3, D4, D5, D6 distance L0 light LE EUV light LR excitation light P0, P1, P2, P3, P4, P5 intersection PT irradiation position PZ Plasma R rotation axis TM, TMa target material

Claims

1. A target holder is provided, The target holder is The bottom and a cylindrical portion having an open end and the other end communicating with the bottom portion; an opposing wall disposed on a rotation shaft side surrounded by the cylindrical portion, the opposing wall facing an inner wall of the cylindrical portion; Including, the inner wall holds a target material that generates plasma when irradiated with excitation light at an irradiation position; the opposing wall intersects with a perpendicular line that is perpendicular to the rotation axis and passes through the irradiation position, a distance from the rotation axis to a bottom end portion of the opposing wall that is a bottom end portion of the opposing wall is greater than a distance from the rotation axis to an intersection point of the opposing wall with the perpendicular line, the cylindrical portion includes an opening-side cylindrical portion at an opening side and a bottom-side cylindrical portion at a bottom side, the excitation light passes through an irradiation space, which is a space between the opening-side cylindrical portion and an opening-side end portion, which is an end portion of the opposing wall opposite to the bottom-side end portion, and irradiates the irradiation position. Light source device.

2. a region between the intersection of the opposing wall with the perpendicular line and the opening-side end portion, the region having a distance from the rotation axis that is smaller than the distance from the rotation axis to the intersection; The light source device according to claim 1 .

3. The opposing wall has a distance from the bottom end to the rotation shaft that gradually decreases as it moves from the bottom end to the opening end.

3. The light source device according to claim 1.

4. The distance from the bottom to the opening-side end is greater than the distance from the bottom to the opening-side cylindrical portion.

3. The light source device according to claim 1.

5. a distance from the rotation shaft to the opening-side cylindrical portion is shorter than a distance from the rotation shaft to the inner wall; 3. The light source device according to claim 1.

6. The irradiation space is formed over the entire circumference along the rotation direction around the rotation axis, 3. The light source device according to claim 1.

7. The opposing wall is formed over the entire circumference along the rotation direction around the rotation axis.

3. The light source device according to claim 1.

8. The opening side end portion is the distance to the rotation axis is greater than the distance from the intersection to the rotation axis, the slits are formed along the entire circumference along the rotation direction around the rotation axis, and the slits have one or more slits arranged along the rotation direction around the rotation axis so as to expose a part of the irradiation space; 3. The light source device according to claim 1.

9. The target material is refilled through the irradiation space.

3. The light source device according to claim 1.

10. the opposing wall has a temperature equal to or higher than the melting point of the target material; The target material is refilled by contacting the opposing wall. The light source device according to claim 9 .

11. The opening of the cylindrical portion faces substantially downward or substantially upward in the direction of gravity.

3. The light source device according to claim 1.

12. an opening of the cylindrical portion faces substantially downward in the direction of gravity; the opening-side cylindrical portion has a groove recessed downward in the direction of gravity; The light source device according to claim 11.

13. The opening of the cylindrical portion faces substantially downward in the direction of gravity, Further provided with a cover part or debris container that covers the opening side cylindrical part from below, 3. The light source device according to claim 1.

14. a light path cover for covering a light path of at least one of the excitation light and the light generated from the plasma, The optical path cover is at least one of attached to the cover part, disposed inside the debris container, and disposed between the cylindrical part and the debris container. The light source device according to claim 13.

15. the light path cover includes a plurality of portions; The light source device according to claim 14.

16. The opening of the cylindrical portion faces substantially downward in the direction of gravity, The plasma generating device further includes a sensor disposed at a position to detect light that passes through at least one of the vicinity of the end of the opening-side cylindrical portion and the vicinity of the opening-side end, 3. The light source device according to claim 1.

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