Freeze Valve of Target Material Generator

Abstract

The freeze valve (100) includes a valve body (128) that defines an axial opening (135) extending along an axial direction, and a wire (140) within the axial opening of the valve body. The wire includes a plurality of strands that define a plurality of continuous fluid paths through the axial opening of the valve body.

Description

Technical Field

[0001] Cross - Reference to Related Applications

[0001] This application claims priority to U.S. Application No. 63 / 356,610, filed on June 29, 2022, which is hereby incorporated by reference in its entirety.

[0002]

[0002] The disclosed subject matter relates to a freeze valve for a target material generator.

Background Art

[0003]

[0003] Extreme ultraviolet (EUV) light, for example, electromagnetic radiation with a wavelength of 100 nanometers (nm) or less (also called soft x - rays), includes light with wavelengths such as 20 nm or less, 5 - 20 nm, or 13 - 14 nm, and can be used to generate extremely small features within or on a substrate (e.g., a silicon wafer) by initiating polymerization in a resist layer in a photolithography process. Methods for generating EUV light include, but are not limited to, changing the physical state of a source material to a plasma state. Source materials include compounds or elements having emission lines in the EUV range (e.g., xenon, lithium, or tin). In such a method, often called laser - produced plasma (“LPP”), the required plasma is generated by irradiating source material in the form of, for example, droplets, streams, or clusters of the source material with an amplified light beam that can be called a drive laser. In this process, the plasma is typically generated within a sealed container such as a vacuum chamber and is monitored using various types of metrology equipment. Source materials such as xenon, lithium, and tin emit in the EUV range when in a plasma state and are targeted and irradiated by the drive laser, and are therefore generally called target materials. Droplets, streams, or clusters of the target material are generated by a target material generator through which the target material is transported.

Summary of the Invention

[0004]

[0004] In one general aspect, a freeze valve includes a valve body defining an axial opening extending along an axial direction, and a wire within the axial opening of the valve body. The wire includes a plurality of strands defining a plurality of continuous fluid paths through the axial opening of the valve body.

[0005]

[0005] The embodiments may include one or more of the following features. For example, the valve body may have a cylindrical shape. The wire may be configured to prevent a solid material from being extruded from the axial opening at a pressure exceeding 10,000 PSI, 20,000 PSI, 30,000 PSI, 100,000 PSI, 200,000 PSI, 300,000 PSI, 400,000 PSI, 500,000 PSI, 600,000 PSI, 700,000 PSI, or 725,000 PSI. The strands of the plurality of strands may be arranged in a spiral within the axial opening, and the continuous fluid path may be a spiral path through the axial opening.

[0006]

[0006] The diameter of each strand may be in the range of 0.2 to 0.3 millimeters (mm), and the diameter of the wire may be in the range of 4 to 6 mm. The region between the plurality of strands may have a cross-sectional area of 0.785 to 7.069 mm 2 and may have a cross-sectional area.

[0007]

[0007] The axial opening of the valve body can be defined with a constant diameter along the length of the wire. The axial opening of the valve body may include a stepped feature, and the wire can be attached between a fixed stop at the first end of the wire and the stepped feature at the second end of the wire. The fixed stop can be a solid disk having a central axial opening or can include a solid disk, the diameter of the central opening being smaller than the outer diameter of the wire and the outer diameter of the solid disk being larger than the outer diameter of the wire. The central axial opening of the fixed stop can be fluidly coupled to a gas source. The fixed stop may also include a fixed stop body extending from the solid disk into the axial opening of the valve body. The fixed stop body includes a central opening that is in fluid communication with the central opening of the solid disk and is also in fluid communication with the axial opening of the valve body. The freeze valve can include a first fluid port and a second fluid port, the first fluid port being defined at the fixed stop. The axial opening can include a primary axial opening and a small-diameter axial opening. The primary axial opening is between the fixed stop and the stepped feature, and the small-diameter axial opening is between the stepped feature and the second fluid port. The diameter of the primary axial opening is larger than the diameter of the small-diameter axial opening.

[0008]

[0008] The valve body can be made of molybdenum or a high melting point metal, and the plurality of wire strands can be made of tungsten or a high melting point metal.

[0009]

[0009] The freeze valve can also include a temperature controller in thermal communication with the valve body. The temperature controller can be configured to adjust the temperature of the target material within the axial opening within a temperature range including the freezing point and melting point of the target material, thereby adjusting the flow of the target material through or within the axial opening.

[0010]

[0010] Each gap between the wire and the inner surface of the valve body may have an area along a direction perpendicular to the axial direction that is less than or equal to the area formed between the strands of the wire. The axial opening may include a small-diameter axial opening adjacent to the primary axial opening, and the wire can be disposed or arranged within the primary axial opening, and when the temperature of the target material is maintained below the freezing point of the target material, a solid-state target material can be formed within the small-diameter axial opening.

[0011]

[0011] The wire may include a first wire and a second wire arranged in series within the axial opening of the valve body, and each of the first wire and the second wire includes a plurality of strands that define a plurality of continuous fluid paths passing through the axial opening of the valve body. The strands of the first wire can be arranged spirally within the axial opening, thereby defining a first spiral path passing through the axial opening, and the strands of the second wire can be arranged spirally within the axial opening, thereby defining a second spiral path passing through the axial opening.

[0012]

[0012] The strands of the plurality of strands can be arranged linearly within the axial opening, and the continuous fluid path can be a linear path passing through the axial opening.

[0013]

[0013] The axial opening of the valve body may include a first step feature and a second step feature, and the wire is attached between the first step feature and the second step feature.

[0014]

[0014] In another general aspect, a target generator includes an ejection nozzle in fluid communication with at least one target material reservoir, and at least one freeze valve in fluid communication with a fluid path defined between the ejection nozzle and the at least one target material reservoir. The freeze valve includes a valve body defining an axial opening extending along an axial direction, and a wire within the axial opening of the valve body. The wire includes a plurality of strands that define a plurality of continuous fluid paths passing through the axial opening of the valve body.

[0015]

[0015] The embodiments may include one or more of the following features. For example, the valve body may have a cylindrical shape. The freeze valve may comprise a fluid port fluidly coupled to a gas source during a purge operation. The freeze valve may comprise a second fluid port that is always in fluid communication with a fluid path defined between an exit nozzle and at least one target material reservoir. The freeze valve may comprise first and second fluid ports interposed within a fluid path defined between an exit nozzle and at least one target material reservoir.

[0016]

[0016] The target generator may also be capable of containing a target material within a fluid path defined between an exit nozzle and at least one target material reservoir. The freeze valve may comprise a temperature controller configured to maintain the target material within the small diameter axial opening of the axial opening at a temperature below its freezing temperature during operation of the exit nozzle, such that the solid target material becomes a stop mechanism configured to reduce or prevent the flow of material through the primary axial opening of the axial opening by the solid target material within the small diameter axial opening. The primary axial opening is adjacent to the small diameter axial opening. The target material may include tin, the valve body of the freeze valve may be made of molybdenum or a high melting point metal, and the strand may be made of tungsten or a high melting point metal.

[0017]

[0017] In another general aspect, a method of controlling a fluid includes freezing a target material within a small-diameter axial opening of a valve body of a freeze valve, such that when an axial pressure in the range of 10,000 to 765,000 PSI is applied to the frozen target material, the frozen target material is prevented from being axially extruded through a plurality of regions formed from wire strands of a wire attached within a primary axial opening of the valve body; thawing the target material within the small-diameter axial opening of the valve body of the freeze valve; and after thawing, enabling fluid to flow through one or more regions of the primary axial opening and the small-diameter axial opening of the valve body of the freeze valve. The primary axial opening has a diameter larger than that of the small-diameter axial opening.

[0018]

[0018] Embodiments can include one or more of the following features. For example, after thawing, the fluid may be able to flow through a region where the lateral spread between the strands of the wire is in the range of 2.0 to 0.5 mm, at a conductivity of 0.03 to 0.001 L / second. The target material can be frozen by maintaining the target material at a temperature below its freezing point for a time sufficient to solidify the target material. The fluid may be able to flow through one or more regions of the primary axial opening and the small-diameter axial opening of the valve body of the freeze valve by enabling a purge gas to enter the primary axial opening from a gas source and flow through the primary axial opening. The method may further include applying pressure to the purge gas while enabling the purge gas to flow, to push back liquid target material present inside and outside the primary axial opening and the small-diameter axial opening, into a target material reservoir.

Brief Description of the Drawings

[0019]

Figure 1A

[0019] A side cross-sectional view of a freeze valve including a valve body defining an axial opening and a wire including wire strands within the axial opening.

Figure 1B

[0020] Provide an axial cross-sectional view of the freeze valve of FIG. 1A taken along line 1B-1B (in the XY plane), which shows the wire strands and the details of the fluid path within the axial opening defined by the wire strands.

Figure 1C

[0021] A perspective view of another example of a wire that can be implemented in the freeze valve of FIGS. 1A and 1B, showing the wire strands and the details of the fluid path within the axial opening defined by the wire strands.

Figure 2A

[0022] A side cross-sectional view of a portion of the freeze valve when the freeze valve of FIG. 1A is in the closed state.

Figure 2B

[0023] A side cross-sectional view of a portion of the freeze valve when the freeze valve of FIG. 1A is in the open state.

Figure 3

[0024] A schematic view showing the freeze valves of FIGS. 1A and 1B within the target material nozzle assembly.

Figure 4A

[0025] A close-up perspective view of an example of a wire including parallel wire strands that can be used within the axial opening of the valve body of the freeze valves of FIGS. 1A and 1B.

Figure 4B

[0026] A close-up perspective view of an example of a wire including helical wire strands that can be used within the axial opening of the valve body of the freeze valves of FIGS. 1A and 1B.

Figure 5A

[0027] A top view of an example of a fixed stop that can be used in the freeze valves of FIGS. 1A and 1B.

Figure 5B

[0028] A side perspective view of the fixed stop of FIG. 5A.

Figure 5C

[0029] A side cross-sectional view of an example of the freeze valves of FIGS. 1A and 1B, including the fixed stops of FIGS. 5A and 5B.

Figure 5D

[0030] A side cross-sectional view of a freeze valve designed similarly to the freeze valves of FIGS. 1A and 1B, comprising the fixed stops of FIGS. 5A and 5B and two wires in series within an axial opening.

Figure 6

[0031] A flowchart showing a procedure for controlling fluid using any of the freeze valves from FIG. 1A to FIG. 5C.

Figure 7A-7F

[0032] A schematic diagram showing the freeze valves of FIGS. 1A and 1B within a target material nozzle assembly during the procedure of FIG. 6.

Figure 8A

[0033] A side cross-sectional view of a dual-wet embodiment of the freeze valves of FIGS. 1A and 1B, in which target material fluid can flow through both fluid ports of the freeze valve.

Figure 8B

[0034] A schematic diagram showing the dual-wet freeze valve of FIG. 8A implemented in a target material nozzle assembly.

Figure 9

[0035] A schematic block diagram showing an embodiment of the target material nozzle assembly of FIG. 3 integrated within a target generator that supplies a target to an EUV light source.

DETAILED DESCRIPTION OF THE INVENTION

[0020]

[0036] Referring to FIGS. 1A and 1B, the freeze valve 100 includes a valve body 128 that defines an axial opening 135 (or a primary axial opening 135) extending along an axial direction generally parallel to the Z-axis. The freeze valve 100 includes a wire 140 within the axial opening 135. The wire 140 is fixed within the axial opening 135 so as to contact the inner surface 122 of the valve body 128. The wire 140 includes a plurality of wire strands 141 (FIG. 1B). A plurality of continuous fluid paths are defined in the regions 160 between adjacent wire strands 141 and in the gaps 161 between the wire strands 141 and the inner surface 122 of the valve body 128. The wire 140 (and each wire strand 141) and the continuous fluid paths (defined by the regions 160 and the gaps 161) extend along the axial opening 135, specifically along the axial direction (parallel to the Z-axis). The axial opening 135 intervenes within the valve body 128 and extends between a fixed stop 105 and a stepped feature 132 formed in the valve body 128 (specifically, the inner surface 122). The fixed stop 105 defines a central axial opening 110 that enables fluid communication between the axial opening 135 and the first fluid port 103A. The stepped feature 132 is where the axial opening 135 fluidly communicates with the small-diameter axial opening 150. The axial opening 135 formed within the valve body 128 is in fluid communication with the first fluid port 103A and the second fluid port 103B.

[0021]

[0037] The freeze valve 100 can be configured to perform two different functions. The first function occurs when the freeze valve 100 is in a closed state. In this state, the freeze valve 100 holds or maintains the (solid) target material, thereby reducing or preventing the flow of solid material through the freeze valve 100. The freeze valve 100 can perform the first function when the target material in the small-diameter axial opening 150 of the freeze valve 100 is sufficiently cooled for a certain period of time and the target material in the small-diameter axial opening 150 becomes solid. When the target material is in a solid state, the solid target material functions as a plug that reduces or prevents the flow of fluid through the freeze valve 100. The second function occurs when the freeze valve 100 is in an open state. In this state, the freeze valve 100 allows or permits the flow of fluid. In order for the fluid to flow through the freeze valve 100 without being obstructed, the target material in the small-diameter axial opening 150 and the target material entering the axial opening 135 need to be sufficiently warmed so that the target material in the small-diameter axial opening 150 and the axial opening 135 becomes fluid. The fluid that can flow through the freeze valve 100 can potentially be a gas, a liquid, or a combination of a gas and a liquid.

[0022]

[0038] Referring to FIG. 2A, the freeze valve 100 is closed and performs a first function where the target material is the solid target material 201S. While the freeze valve 100 is closed, it is necessary to reduce or prevent the solid target material 201S from being pushed out of the freeze valve 100 from within the small-diameter axial opening 150 under the expected operating pressure P applied along the Z direction (e.g., the -Z direction). Generally, in a conventional freeze valve, the pressure P that can be applied along the -Z direction can usually reach up to 10,000 pounds per square inch (PSI), which is the maximum valve Pmax, before the solid target material starts to be pushed out from the freeze valve along the -Z direction. The "punch pressure" (represented by the following formula (1)) is defined as the pressure at which the solid target material within the small-diameter axial opening of the freeze valve is pushed out of that freeze valve. On the other hand, the freeze valve 100 is designed to prevent the solid target material 201S within the small-diameter axial opening 150 from being pushed out along the -Z direction into the axial opening 135 and out of the freeze valve 100, even when the punch pressure reaches up to 725,000 PSI, which is the maximum value Pmax, when the freeze valve 100 is closed (during the execution of the first function). The punch pressure PP of the freeze valve 100 100 increases by reducing the diameter or range of the opening through which the solid target material 201S within the small-diameter axial opening 150 can be pushed out (along a plane perpendicular to the Z axis). This is because the punch pressure PP of the freeze valve 100 100 is inversely proportional to the square of the diameter or range of the opening axially positioned along the -Z direction from the small opening 150. Also, because the wire strand 141 is attached within the axial opening 135, when an axial pressure P is applied along the -Z direction, the solid target material 201S within the small-diameter axial opening 150 is pressed against an opening that is much smaller in the axial (-Z direction) (specifically, first the region 160 and secondarily the gap 161, although less likely).

[0023]

[0039] Figure 1B shows a cross-section 1B-1B that intersects the axial opening 135 of the valve body 128. Also visible in Figure 1B is a small-diameter axial opening 150 positioned beyond the step feature 132. Under the axial pressure P along the -Z direction, the solid target material 201S within the small-diameter axial opening 150 is pressed against the solid end portion that fits within the diameter D of the opening 150 of the wire strand 141. Also, under the axial pressure P along the -Z direction, the solid target material 201S within the small-diameter opening 150 is pushed into the region 160 when it exceeds the punch pressure PP 150 Normally, the punch pressure is calculated assuming that the opening where the solid target material 201S is held and the opening where the solid target material 201S is to be extruded are cylindrical. However, here, the opening (region 160) is not cylindrical but is close to a polygonal shape such as a triangle. Nevertheless, it is clear that the range or diameter D of each region 160 100 is much smaller than the diameter D of the axial opening 135 160 Furthermore, since the small-diameter axial opening 150 is axially centered on the wire 140, the solid target material 201S within the small-diameter axial opening 150 is not in direct fluid communication with the gap 161 that is normally blocked by the step feature 132. The solid target material 201S that is pushed into the gap 161 somehow will travel along a path that is not parallel to the Z direction, and thus, will experience greater friction. For these reasons, in response to the pressure P being applied along the -Z direction, a greater force is applied by the solid target material 201S along the +Z direction. This greater friction is due to the plurality of wire strands 141 within the axial opening 135 forming a much smaller opening (via the region 160) through which the solid target material 201S within the small-diameter axial opening 150 can be extruded. Thus, the punch pressure PP 135 that causes the solid target material 201S to flow along the -Z direction through the axial opening 135 where the wire 140 is attached 100 is the punch pressure PP that causes the solid target material 201S to pass through the axial opening 135 without the wire 140 oMuch larger. For example, the punch pressure PP 100 is the punch pressure PP o and may be twice, three times, four times, ten times, twenty times, thirty times, forty times, fifty times, sixty times, seventy times, or more than seventy-one times as large. Therefore, the punch pressure PP 100 of the freeze valve 100 is at least 10,000 PSI, at least 20,000 PSI, at least 30,000 PSI, at least 100,000 PSI, at least 200,000 PSI, at least 300,000 PSI, at least 400,000 PSI, at least 500,000 PSI, at least 600,000 PSI, at least 700,000 PSI, or about 725,000 PSI.

[0024]

[0040] Next, in the calculation of the punch pressure PP 100 it is assumed that the opening is cylindrical, and therefore these calculations are an approximation of the actual punch pressure PP 100 of the freeze valve 100.

[0025]

[0041] The punch pressure PP 100 of the above freeze valve 100 can be approximated by calculating the punch pressure PP 160 for extrusion through one region 160 according to the following punch pressure extrusion formula (1).

[0026]

Equation

[0027] In Equation (1), the variable D0 is the range of the area pushed into a specific region 160 within the diameter D 150 of the small-diameter axial opening 150 (shown in FIG. 1B), D f is the range D 160 of that specific region 160 (shown in FIG. 1B), and L is the length L 150 along the Z-axis of the small-diameter axial opening 150 (shown in FIG. 1A).and a and b are the angles A in the region of the step feature portion 132 where the small-diameter axial opening 150 is connected to the axial opening 135 150-1 and A 150-2 (shown in FIG. 1A), K is a strength coefficient, and n is the elasticity of the valve body 128. As is clear from Equation (1), the punch pressure PP 160 is affected by the number of wire strands 141 in the wire 140 such that the size of the small diameter D 160 is affected, and thus the value of D f is affected, and depends on the number of wire strands 141 in the wire 140. The overall punch pressure PP 100 of the freeze valve 100 is calculated based on the value of the punch pressure PP 160 in one region 160.

[0028]

[0042] For example, referring to FIG. 1C, for the wire 140C in the axial opening 135 of the valve body 128C including a total of 337 wire strands 141C, the punch pressure PP 160 can be calculated. The wire 140C also includes a plurality of continuous fluid paths that define a region 160C between adjacent wire strands 141C and a gap 161C between the wire strands 141C and the inner surface 122C of the valve body 128C. For simplicity, in the following calculations, it is assumed that the wire strands 141C are straight and thus extend only axially along the Z direction. If the overall diameter of the wire 140C is 5 millimeters (mm) (the diameter D 135 of the axial opening 135 is also about 5 mm or slightly larger), and the wire 140C includes 337 wire strands 141C, the diameter D f (D 160 ) of each region 160C is about 0.056 mm, and the diameter D0 is about 0.185 mm. When the length L 150 is 34 mm, a = 0.8, b = 1.5, K = 69 bar, and n = 0.05, the punch pressure PP 160is about 300,000 PSI. As described above, in the above calculation, it is assumed that the wire strand 141C and the region 160C are straight lines. However, the wire 140C can be designed with a helical strand 141C, and thus the region 160C will also be helical. With this design, the solid target material 201S to be extruded will be extruded along a direction including a component perpendicular to the +Z direction, so it will experience greater friction, and the actual punch pressure PP 160 will be even higher.

[0029]

[0043] Referring to FIG. 2B, the freeze valve 100 is open and is performing a second function in which the target material within the freeze valve 100 is liquid. While the freeze valve 100 is open, it is necessary to guide the fluid 202F within the axial opening 135 of the freeze valve 100 at an acceptable speed. The fluid 202F may be a target material in a fluid or liquid state, or may include a target material in a fluid or liquid state. The fluid 202F may similarly or alternatively include a fluid substance such as a purge gas 204G, or a combination of gas and liquid. The speed at which the fluid 202F is guided within the axial opening 135 of the freeze valve 100 is referred to as the "conductivity" of the freeze valve 100. The conductivity needs to be above an acceptable speed at which the freeze valve 100 can effectively guide the fluid 202F within the axial opening 135. The freeze valve 100 is the punch pressure PP 100The design enables the freeze valve 100 to perform a first function (Figure 2A) that can be at least 725,000 PSI, such that the conductivity of the fluid 202F passing through the freeze valve 100 during the execution of the secondary function is not adversely affected. The freeze valve 100 is designed such that the conductivity of the flow of fluid 202F passing through the freeze valve 100 when performing the second function is improved compared to conventional freeze valve designs. In particular, the conductivity of the flow of fluid 202F through the freeze valve 100 is (e.g., linearly) proportional to the number of regions 160 and gaps 161 defined within the axial opening 135, and such regions 160 and gaps 161 exist because the wire 140 is held within the axial opening 135 and the wire 140 includes a plurality of wire strands 141. The conductivity of the flow of fluid 202F through the valve body 128 depends on the total cross-sectional area of the continuous path between the first fluid port 103A and the second fluid port 103B.

[0030]

[0044] Referring to Figure 1C, as described above, the wire 140C includes a total of 337 wire strands 141C. The wire 140C also includes a plurality of continuous fluid paths that define a region 160C between adjacent wire strands 141C and a gap 161C between the wire strands 141C and the inner surface 122C of the valve body 128C. As described above, the conductivity of the fluid 202F passing through the freeze valve 100 to which the wire 140C is attached is proportional to the number of regions 160C and gaps 161C defined by the wire 140C and their relationship within the valve body 128C, and also proportional to the total cross-sectional area of the continuous path between the first fluid port 103A and the second fluid port 103B (Figure 1A). Thus, an estimate of the conductivity of the freeze valve 100 including the wire 140C can be calculated as follows. Note that the wire strands 141C have a helical shape, so the regions 160C and gaps 161C are helical. For simplicity, in the following calculations, it is assumed that the wire strands 141C are straight and thus extend only axially along the Z direction. The overall diameter of the wire 140C is 5 millimeters (mm) (the diameter D of the axial opening 135 135When the wire 140C also has a diameter of about 5 mm or slightly larger and contains 337 wire strands 141C, the diameter D of each region 160 160 is about 0.056 mm, and the diameter D of each gap 161 161 is about 0.34 mm. There are about 265 regions 160 and 61 gaps 160. In this example, the conductivity of the freeze valve 100 may be about 0.0326 liters per second (L / s). A freeze valve of equivalent size without the wire 140C disposed within the valve body 128C may have a conductivity of about 0.0001 L / s under similar operating conditions.

[0031]

[0045] When the freeze valve 100 is functioning in the open state (as shown in FIG. 2B), it allows the flow of fluid 202F through the valve body 128. The fluid 202F may be a gas 204G such as a purge gas or a forming gas fed from a gas system 312 (as shown in FIG. 3) that is compatible with the valve body 128 or may include the same. Such a purge gas or forming gas may be a gas that does not react with the materials of the target material and features attached to or within the valve body 128, such as the axial opening 135 that holds the fixed stop 105 and the wire 140 including the plurality of wire strands 141. The purge gas or forming gas may include, for example, an inert gas such as argon or hydrogen. The fluid 202F may also include the target material in a liquid state that remains within the freeze valve 100. The fluid 202F may be directed from an external gas system 312 (FIG. 3) through the first fluid port 103A, the central axial opening 110 of the fixed stop 105, the axial opening 135 within the valve body 128, and the second fluid port 103B.

[0032]

[0046] Thus, the improvement in the punch pressure PP 100 and the maintenance (and improvement) of the conductivity of the freeze valve 100 are the result of fixing the wire 140 including the plurality of wire strands 141 to the axial opening 135, as will be considered in more detail below.

[0033]

[0047] Referring back to FIGS. 1A and 1B, the valve body 128 extends in an axial direction parallel to the Z-axis. The axial opening 135 is typically along the length L of the wire 140 140 defined by a constant diameter (D 135 ). The valve body 128 may be cylindrical and thus defines a cylindrical outer surface 125. The valve body 128 is of a continuous shape and made of a material hard enough to withstand the pressure applied to the freeze valve 100 (such as the pressure P applied to the solid target material 201S or the pressure when the gas 204G is supplied). The diameter of the cylindrical outer surface 125 may vary as it extends parallel to the Z-axis. For example, the valve body 128 may be larger in diameter at the location where the fixed stop 105 is attached (as shown in FIG. 1A) and smaller in diameter at the location where the valve body 128 includes the small-diameter axial opening 150 (as shown in FIG. 1A).

[0034]

[0048] The valve body 128 and the wire strands 141 of the wire 140 are each made of a material that is compatible with and non-reactive to the materials in contact with the valve body 128 and the wire strands 141, including the target material (in solid or fluid state) and the gas 204G. For example, when the freeze valve 100 is used in a target material nozzle assembly 334 configured to supply a target to an EUV light source (shown in FIG. 9), the target material may include tin or a tin alloy. In this example, the valve body 128 may be made of a high-melting-point metal such as molybdenum, tungsten, niobium, rhenium, or an alloy of these metals. Also, the wire strands 141 may be made of a high-melting-point metal such as tungsten.

[0035]

[0049] As shown in FIG. 1A, the valve body 128 includes an inner surface 122 that defines an axial opening 135, and the wire 140 is interposed (or attached) between the fixed stop 105 and the step feature 132. The fixed stop 105 is attached to the first end 108 of the valve body 128. The fixed stop 105 may have a cylindrical disk shape that complements the shape of the first end 108 of the valve body 128. The fixed stop 105 is made of a solid rigid material that can withstand the pressure that can be applied from the solid target material 201S or the fluid 202F. The rigid disk shape of the fixed stop 105, when attached, defines a central axial opening 110 that fluidly couples the first fluid port 103A to the axial opening 135. The diameter D 110 of the central axial opening 110 of the fixed stop 105 is smaller than the diameter D 135 of the axial opening 135 so as to prevent the wire 140 from moving along the -Z direction. The step feature 132 within the valve body 128 is adjacent to a small-diameter axial opening 150 that is in fluid communication with the axial opening 135, and thus the small-diameter axial opening 150 extends parallel to the Z-axis. The step feature 132 forms an intersection between the small-diameter axial opening 150 and the axial opening 135 having a diameter larger than that of the small-diameter axial opening 150. The step feature 132 and the fluid-connected small-diameter axial opening 150 are formed such that the fluid 202F (such as a target material or a purge gas) can flow between the axial opening 135 and the small-diameter axial opening 150. The small-diameter axial opening 150 is composed of a diameter D 135 smaller than the diameter D 150 of the axial opening 135. Accordingly, the wire 140 including a plurality of wire strands 141 is held, confined, and statically held within the valve body 128 between the fixed stop 105 and the step feature 132. Further, the wire 140 including a plurality of wires 141 remains fixed in place when interposed between the fixed stop 105 and the step feature 132 within the axial opening 135 of the valve body 128 when the freeze valve 100 is configured to function in either a closed or open state (as shown in FIGS. 2A and 2B).

[0036]

[0050] FIG. 3 shows an embodiment 300 of a freeze valve 100 used in a target material nozzle assembly 330. The target material nozzle assembly 330 includes a nozzle 334 in fluid communication with a reservoir 338. The reservoir 338 is configured to hold a liquid target material 331. By forming a fluid flow path 337 between the reservoir 338 and the nozzle 334, the liquid target material 331 stored in the reservoir 338 is supplied to the nozzle 334. Although not shown in FIG. 3, the fluid flow path 337 may include other components such as additional valves (such as the additional valve shown in FIG. 8A) or reservoirs to enable additional control of the liquid target material 337. The nozzle 334 can be made of a capillary 336 that extends generally along a longitudinal direction and defines an opening 335. The opening 335 is at an end of the capillary 336. The capillary 336 can be made of glass in the form of, for example, fused silica, borosilicate, aluminosilicate, or quartz. The liquid target material 331 flows through the capillary 336 and is discharged from the opening 335. When the pressure applied to the reservoir 338 is greater than a certain pressure (such as the Laplace pressure), the liquid target material 331 exits the opening 335 as a target flow (as shown in FIG. 7C below).

[0037]

[0051] In the position shown in FIG. 3, the freeze valve 300 is a purge or service freeze valve in fluid communication with a fluid flow path 337 between the nozzle 335 and the reservoir 338. The freeze valve 300 is an embodiment of the freeze valve 100 and includes a first fluid port 303A, a second fluid port 303B, and a valve body 328 between the first fluid port 303A and the second fluid port 303B. The first fluid port 303A includes a fixed stop 305 with a central axis direction opening 310 fluidly coupled to a gas system 312, while the second fluid port 303B is in fluid communication with the fluid flow path 337.

[0038]

[0052] The freeze valve 300 also includes a temperature control device 313 configured to control the temperature at which the freeze valve 300 can perform its function of opening and closing the freeze valve 300. For example, the temperature control device 313 may be a cartridge heater in thermal communication with the valve body 328 of the freeze valve 300. When the temperature control device 313 maintains the temperature of the valve body 328 significantly lower than the melting point of the liquid target material 331, the liquid target material 331 within the small-diameter axial opening 350 of the freeze valve 300 solidifies (changes from a liquid to a solid state), and this solid target material within the smaller axial opening 350 functions as a plug, thereby reducing or preventing fluid (such as the liquid target material 331 or gas from the gas system 313) from flowing through the freeze valve 300. When the temperature control device 311 maintains the temperature of the valve body 328 higher than the melting point of the liquid target material 331, the solid target material within the small-diameter axial opening 350 melts to form the liquid target material 331. Further, thereby, the liquid target material 331 and the gas from the gas system 331 can flow freely through the freeze valve 300.

[0039]

[0053] The freeze valve 100 (FIGS. 1A and 1B) discussed previously includes a valve body 128 with a wire 140 defining a plurality of wire strands 141. The wire 140 including the wire strands 141 may be formed to collectively create different axial geometries that extend parallel to the Z-axis within the axial opening 135 of the freeze valve 100 (shown in FIGS. 4A and 4B). The collective axial geometry formed by the wire strands 141 attached within the valve body 128 can vary the shape and cross-sectional area of the continuous fluid path defined by the regions 160 and gaps 161 between adjacent wire strands 141 and between the wire strands 141 and the inner surface 122 of the axial opening 135. Also, since the conductivity of the fluid passing through the valve body 128 depends on the total cross-sectional area of the continuous path (such as regions 160 and gaps 161), the collective axial geometry created by the wire strands 141 can change the conductivity of the fluid flow and, consequently, the punch pressure.

[0040]

[0054] FIGS. 4A and 4B show an exemplary axial geometry formed by a wire (including a plurality of wire strands) that can be mounted within the axial opening 135 of the valve body 128 of the freeze valve 100.

[0041]

[0055] In the embodiment of FIG. 4A, a wire 440-1 including a plurality of wire strands 441-1 is shown. Specifically, wire 440-1 includes 19 wire strands 441-1. Each wire strand 441-1 maintains a linear shape along the Z-axis, and the wire strands 444-1 collectively extend closely and create a larger radial shape that forms wire 440-1 by contacting each other in parallel. Wire 440-1 includes a linearly extending gap 461-1 defined by the radially spreading parallel wire strands 441-1. When the wire strands 441-1 are also mounted within the axial opening 135, they define a linearly extending region 461-1 between the wire strands 441-1 and the inner surface 122 within the valve body 128 of the freeze valve 100.

[0042]

[0056] Referring to the embodiment of FIG. 4B, wire 440-2 includes a plurality of wire strands 441-2. Each wire strand 441-2 extends spirally together in the same direction or at the same angle along the Z-axis to create a helical wire 440-2. Wire 440-2 includes a gap 461-2 formed by a path created by the helical wire strands 441-2 that extend very closely together in the same direction. The path of gap 462-2 is also helical. Also, wire 440-2 defines a region 461-2 that extends between the wire strands 441-2 and the inner surface 122, such as when it is mounted within the valve body 128 including the inner surface 122 of the freeze valve 100, to allow fluid to flow further.

[0043]

[0057] Referring to FIGS. 5A and 5B, an embodiment 505 of the fixed stop 105 is shown. The fixed stop 505 includes a disk 506 and a fixed stop body 507 extending axially from the disk 506. Similar to the fixed stop 105 (shown in FIG. 1A), the fixed stop 505 has a central axial opening 510 extending through the disk 506 and the fixed stop body 507 with a diameter D 510 and having. Also, the fixed stop body 507 has an outer diameter smaller than the outer diameter of the disk 506. The fixed stop body 507 extends axially from the disk 506 by a length L 507 .

[0044]

[0058] Referring to FIG. 5C, an embodiment 500 of the freeze valve 100 includes the fixed stop 505. In this embodiment, the fixed stop body 507 extends into a portion of the valve body 528. The valve body 528 of the freeze valve 500 (similar to the freeze valve 100 shown in FIG. 1A) is provided with an axial opening 535. The freeze valve 500 also includes a wire 540 in the axial opening 535, and the wire 540 is attached between the end 518 of the fixed stop body 507 and a step feature 532 formed on the valve body 528. The wire 540 extends along the Z direction by a length L 540 . Beyond the step feature 523 along the Z direction, a small-diameter axial opening 550 is fluidly connected to the second fluid port 503B, and the small-diameter axial opening 550 is also fluidly connected to the axial opening 535. Also, the axial opening 535 is fluidly connected to the central axial opening 510 of the fixed stop 505, and the central axial opening 510 of the fixed stop 505 is in fluid communication with the first fluid port 503A. The fixed stop 505 extends along the Z direction for the entire length L within the axial opening 535 of the valve body 528 507 . The diameter D of the central axial opening of the fixed stop 505 510 is smaller than the diameter D of the axial opening 535 of the valve body 528 535 . In this way, the wire 540 remains at a predetermined position between the fixed stop 505 and the step feature 532. Further, the length L of the fixed stop body 507 507can be of any suitable length and can be selected according to the length L of the wire 540 540 For example, if the total length (the sum of the lengths L 507 and L 540 ) of the axial opening 535 is 34 mm and the length L 507 of the fixed stop body 507 is 10 mm, the length L 540 of the wire 540 is 24 mm. As another example, if the total length (the sum of the lengths L 507 and L 540 ) of the axial opening 535 is 60 mm and the length L 540 of the wire is 30 mm, the length L 507 of the fixed stop body 507 needs to be 30 mm.

[0045]

[0059] Referring to FIG. 5D, in an additional embodiment, the freeze valve 500 of the axial opening 535 may include wires composed of two or more wires such as the first wire 540-1 and the second wire 540-2. When two or more wires (such as the first wire 540-1 and the second wire 540-2) are arranged in series within the axial opening 535, the total length or overall length of the wires extends parallel to the Z-axis and can be attached in the same manner as a single wire 540 within the axial opening 535 (FIG. 5C). For example, if the length L 535 of the axial opening 535 is 34 mm and the length L 507 of the fixed stop body 507 extends 14 mm within the axial opening 535, the first wire 540-1 and the second wire 540-2 are arranged in series, each extending a length L 540-1 and L 540-2 by 10 mm, and the total length may be 20 mm. Further, when the axial opening 535 includes two wires such as the first wire 540-1 and the second wire 540-2 arranged in series, there is a discontinuity (or break) at the point where the first wire 540-1 touches the second wire 540-2. This break created by the first wire 540-1 and the second wire 540-2 blocks the fluid path within the axial opening 535. The blocking of the fluid path acts as a grain boundary that hinders dislocation movement, thereby increasing the punch pressure P applied along the Z direction of the freeze valve 500.

[0046]

[0060] Referring to FIG. 6, procedure 670 is performed by a freeze valve 700 (which can be freeze valve 100, 300, or 500) used in the target material nozzle assembly 730. The steps of procedure 670 are shown with reference to the freeze valve 700 in the target material nozzle assembly 740 of FIGS. 7A - 7F. To show the operation of the freeze valve 700, the features shown (such as the wire 740 including the wire strands 741) are exaggerated and not to actual scale. Further, for simplicity, only three separate wire strands 741 are shown, and the regions 760 and gaps 761 between the wire strands 741 are depicted between the strands 741 and the inner surface 722 of the valve body 728. However, as described above, additional wire strands 741 can be formed (creating more regions 760 and gaps 761), and in a cross - sectional view of the valve body 728, the wire strands 741 may be in contact with each other. As described above, the number of regions 760 and gaps 761 within the axial opening 735 of the valve body 728 affects the conductivity of the freeze valve 700. Also, when procedure 670 refers to a solid target material, it is represented as solid target material 701S in FIGS. 7A - 7F. When procedure 670 refers to a fluid (such as a liquid) target material, it is represented as liquid target material 701L in FIGS. 7A - 7F. The purge gas or forming gas is represented as gas 704G in FIGS. 7A - 7F.

[0047]

[0061] Procedure 670 begins with cooling the target material present within the small-diameter axial opening 750 of the valve body 728 (671). As shown in FIG. 7A, at the start of step 671, the target material present within the small-diameter axial opening 750 may include the liquid target material 701L. At the start of step 671, the liquid target material 701L has already flowed into the small-diameter axial opening 750 through the second fluid port 703B that is in fluid communication with the fluid path 737 between the reservoir 738 and the nozzle 734. Also, at this point, the gas system 712 applies a pressure Pp along the +Z direction of the (valve 700) to reduce or prevent the liquid target material 701L within the small-diameter axial opening 750 from flowing (or leaking) through the axial opening 735, the first fluid port 703A, and the central axial opening 710 of the fixed stop 705. At the start of step 671, the nozzle 734 is frozen, that is, the nozzle 734 is maintained at a temperature below the freezing point of the target material, freezing the target material so that only the solid target material 701S is present within the nozzle 734 and the nozzle 734 is effectively closed. Thus, the liquid target material 701L is not flowing into the nozzle 734.

[0048]

[0062] In some embodiments, or to accelerate the cooling process, the liquid target material 701L can be actively cooled (671) by the temperature control device 713. In other embodiments where the melting point of the liquid target material 701S is higher than the ambient temperature, for example, when the target material includes tin having a melting point of about 232 °C, the liquid target material 701L can be passively cooled (671) by removing the heat source applied to the valve body 728 (for example, by turning off the temperature control device 713).

[0049]

[0063] When the liquid target material 701L in the small-diameter axial opening 750 of the freeze valve 700 is completely frozen (672), the freeze valve 700 may operate in the closed state shown in FIG. 7B. In the closed state, the frozen valve 700 holds or maintains the solid target material 701S. Specifically, due to the design of the freeze valve 700, the solid target material 701S is prevented from being axially extruded from the valve body 728 even when the pressure P applied through the second fluid port 703B along the -Z direction of the freeze valve 700 (FIG. 7B) is as high as 725,000 PSI (673). In particular, when the pressure P remains less than the punch pressure of 725,000 PSI, the flow of the solid target material 701S is significantly reduced or prevented from moving axially along the -Z direction of the freeze valve 700 (FIG. 7B) through the axial opening 735 to the first fluid port 703A because the solid target material 701S functions as a plug within the small-diameter axial opening 750.

[0050]

[0064] At this point in procedure 670, referring to FIG. 7C, since the freeze valve 700 is closed, the target material nozzle assembly 730 may operate in a supply mode where the nozzle 734 is thawed (so that the solid target material 701S located in the nozzle 734 melts) and the liquid target material 701L stored in the reservoir 738 is supplied to the nozzle 734 under the pressure P. When the pressure P increases to a value greater than a predetermined minimum nozzle pressure, due to the geometry of the nozzle 734, the liquid target material 701L exits the nozzle 734 as a flow 780 of the target 782. For example, the predetermined minimum nozzle pressure may be about 100 PSI.

[0051]

[0065] When it is necessary to repair or replace the nozzle 734, a purge instruction is received (674). At this point, the gas system 712, the freeze valve 700, and the nozzle 734 cooperate to remove the liquid target material 701L from the fluid flow path 737 between the nozzle 734 and the reservoir 738. To do this, the nozzle 734 needs to be frozen (by the above method), and then the freeze valve 700 needs to be changed from the closed state (shown in FIG. 7B) to the open state. The temperature control device 713 starts to actively warm the solid target material 701S in the freeze valve 700 (675). FIG. 7D shows this active warming while a part of the solid target material 701S has melted into the liquid target material 701L. During this time, the pressure P applied to the liquid target material 701L decreases, and since the target material (now the solid target material 701S) in the nozzle 734 is frozen, the liquid target material 701L is no longer actively supplied to the nozzle 734. Therefore, the nozzle 734 stops generating the flow 780 of the target 782. When the nozzle 734 stops generating the flow 780 of the target 782, a part of the liquid target material 701L may remain in the fluid flow path 737 between the nozzle 734 and the reservoir 738.

[0052]

[0066] When all of the solid target material 701S is dissolved (676), the fluid can flow from the first fluid port 703A through the axial opening 735 of the valve body 728 to the second port 703B. Since purging is being performed, the gas system 712 supplies purge gas or forming gas 704G (under pressure Pp) along the +Z direction of the valve 700 (FIG. 7E) via the first port 703A of the freeze valve 700. As shown in FIG. 7E, first, the gas 704G fluidly coupled via the fixed stop 705 enters the first fluid port 703A and the central axial opening 710 within the fixed stop 705. Next, the gas 704G enters the axial opening 735 that includes a plurality of continuous fluid paths (defined by regions 760 and gaps 761) between the adjacent wire strands 741 and the inner surface 722 of the axial opening 735. Thereafter, the gas 704G enters the small-diameter axial opening 750 and flows through the second fluid port 703B. The gas 704G also pushes out the liquid target material 701L from the freeze valve 700 and from the fluid flow path 737. The gas 704G is pushed through the freeze valve 700 with a certain conductivity, and the conductivity increases with the number of regions 760 and gaps 761 defined between the adjacent wire strands 741 and the inner surface 722 of the axial opening 735 of the valve body 728. Finally, all of the liquid target material 701L that was within the freeze valve 700 and the fluid flow path 737 is pushed back into the reservoir 738 by the gas 704G. Further, at this moment, it is possible to occur rapidly as the conductivity of the gas 704G passing through the freeze valve 700 becomes higher.

[0053]

[0067] FIG. 7F shows the state of the freeze valve 700 and the target material nozzle assembly 730 when purging is completed (678). When purging is completed (678), the nozzle 734 can be repaired or removed.

[0054]

[0068] Step 670 may further include an additional step of determining whether the repair or replacement of the nozzle 734 is complete and an instruction to operate the nozzle 734 under normal operating conditions has been received. At this time, as shown in FIG. 7A, the liquid target material 701L can be resupplied from the reservoir 738 into the fluid flow path 737 and the valve body 728 of the freeze valve 700.

[0055]

[0069] Referring to FIGS. 8A and 8B, an embodiment 800 of a freeze valve 100 is shown. The freeze valve 800 may be implemented and may function at least partially similarly to the above-described freeze valves (100, 300, 500, and 700). The freeze valve 800 can be regarded as a dual wet target material valve through which the liquid target material can flow through both the first fluid port 803A and the second fluid port 803B at a specific moment during operation. In this way, the freeze valve 800 can be disposed within the fluid flow path 337 through which the target material flows between the reservoir 338 and the nozzle 334, as shown in FIG. 8B.

[0056]

[0070] The freeze valve 800 includes a valve body 828 that extends parallel to the Z-axis. The valve body 828 defines an axial opening 835 that includes a wire 840. The wire 840 is designed in the same manner as the above-described wires 140, 340, 540, 750. Specifically, the wire 840 includes a plurality of wire strands 841 that form a plurality of continuous fluid paths defined by regions 860 between adjacent wire strands 841 and gaps 861 between the wire strands 841 and the inner surface 822 of the valve body 828. The wire 840 is held within the axial opening 835 between a first stepped feature 832-1 and a second stepped feature 832-2 between a first smaller-diameter axial opening 850-1 and a second smaller-diameter axial opening 850-2. The first smaller-diameter axial opening 850-1 is in fluid communication with a first fluid port 803A, and the second smaller-diameter axial opening 850-2 is in fluid communication with a second fluid port 803B. Thus, there is a continuous fluid path within the valve body 828 between the first fluid port 803A and the second fluid port 803B through the first smaller axial opening 850-1, the axial opening 835, and the second smaller axial opening 850-2.

[0057]

[0071] Similar to the above-described freeze valves (such as 100, 300, 500, and 700), the freeze valve 800 can perform the function of controlling the fluid flow of the target material through a closing operation and an opening operation. The closed freeze valve 800 can hold a sufficiently cooled target material in a solid state within the first and second smaller-diameter axial openings 850-1 and 850-2, extruded into the axial opening 835 and without exiting therefrom, with a pressure of up to 725,000 PSI applied along the +Z or -Z direction of the freeze valve 800 (Figure 8A). The freeze valve 800 can also function such that, in an open state, the target material that is thawed (by an external temperature control device such as 713 shown in Figures 7A to 7E) to be in a liquid state can flow in both directions (the +Z and -Z directions of the freeze valve 800, Figure 8A) within the freeze valve 800.

[0058]

[0072] As shown in FIG. 8B, a freeze valve 800 with external temperature control (such as external temperature control 313) enables a state change of the target material (from solid to liquid, etc.) and further enables control of the flow of the target material through the fluid flow path 337. In a more complex target material nozzle assembly 330 with additional components, additional fluid flow paths, and reservoirs, multiple freeze valves 800 can be implemented at various locations to control the flow of the target material within the assembly.

[0059]

[0073] Referring to FIG. 9, a target material nozzle assembly 730 (or 330) can be incorporated into a target generator 990 that includes fluid flow paths and additional reservoirs, in addition to other fluid regulating devices or valves (such as the freeze valve 800 shown in FIGS. 8A and 8B). The target generator 990 may also include a priming system configured to receive a solid material containing the target material. An example of such a target 990 is shown in WO2020 / 187617, which is hereby incorporated by reference in its entirety.

[0060]

[0074] The target generator 990 supplies a liquid target material 701L to an external system 992 in the form of a flow 780 of targets 782. When the system 992 is an EUV light source, each target 782 is sent to a plasma formation location 993 within a vacuum chamber 994. The plasma formation location 993 can receive at least one light beam 995 (which can be a pulsed light beam) generated by a light source 995 and sent through an optical path 996 to the vacuum chamber 994. Interaction between the pulse of the light beam 995 and the target material within the target 782 at the plasma formation location 993 generates a plasma that emits EUV light 997, which is collected (998) and supplied to a lithography exposure apparatus 999. In this example, the liquid target material 701L can be any material such as water, tin, lithium, and / or xenon that emits EUV light when in a plasma state (998).

[0061]

[0075] Other embodiments are within the scope of the following claims. The features of the freeze valves (100, 300, 500, 700, or 800) may be of other geometric shapes or forms and may be made of materials other than those described. For example, the valve body 128 of the freeze valve 100 may be formed in a shape other than a cylindrical shape, and the cross-section of the valve body taken in the XY plane may not be circular but may be a polygon such as a hexagon. The valve body 128 and the wire 140 can be made of materials other than high melting point metals such as stainless steel, polymers (such as plastics and resins), or wood. The geometric form and material of the freeze valve 100 are determined by the operating parameters (such as pressure and temperature) and the environment in which the freeze valve 100 is used, in addition to the manufacturing cost and method.

[0062]

[0076] The embodiments can be further described using the following clauses. 1. A valve body defining an axial opening extending along an axial direction, and a wire within the axial opening of the valve body, the wire including a plurality of strands defining a plurality of continuous fluid paths passing through the axial opening of the valve body A freeze valve comprising. 2. The freeze valve of clause 1, wherein the valve body has a cylindrical shape. 3. The freeze valve of clause 1, wherein the wire is configured to prevent a solid material from being extruded from the axial opening at a pressure exceeding 10,000 PSI, 20,000 PSI, 30,000 PSI, 100,000 PSI, 200,000 PSI, 300,000 PSI, 400,000 PSI, 500,000 PSI, 600,000 PSI, 700,000 PSI, or 725,000 PSI. 4. The freeze valve of clause 1, wherein the strands of the plurality of strands are spirally arranged within the axial opening, and the continuous fluid path is a spiral path passing through the axial opening. 5. The freeze valve of clause 1, wherein each strand has a diameter in the range of 0.2 to 0.3 millimeters (mm), and the diameter of the wire is in the range of 4 to 6 mm. 6. The area of the region between the plurality of strands is 0.785 to 7.069 mm 2 The freeze valve of clause 5 having a cross-sectional area of 7. The freeze valve of clause 1, wherein the axial opening of the valve body is defined by a constant diameter along the length of the wire. 8. The axial opening of the valve body includes a stepped feature, and the wire is attached between a fixed stop at the first end of the wire and the stepped feature at the second end of the wire. The freeze valve of clause 7. 9. The freeze valve of clause 8, wherein the fixed stop comprises a solid disk having a central axial opening, the central opening having a diameter smaller than the outer diameter of the wire, and the outer diameter of the solid disk being larger than the outer diameter of the wire. 10. The freeze valve of clause 9, wherein the central axial opening of the fixed stop is fluidly coupled to a gas source. 11. The freeze valve of clause 9, wherein the fixed stop further comprises a fixed stop body extending from the solid disk into the axial opening of the valve body, the fixed stop body having a central opening that is in fluid communication with the central opening of the solid disk and also in fluid communication with the axial opening of the valve body. 12. The freeze valve of clause 8 further comprising a first fluid port defined in the fixed stop and a second fluid port, the axial opening including a primary axial opening between the fixed stop and the stepped feature and a small-diameter axial opening between the stepped feature and the second fluid port, the primary axial opening having a diameter larger than the diameter of the small-diameter axial opening. 13. The freeze valve of clause 1, wherein the valve body is made of molybdenum or a high melting point metal, and the plurality of wire strands are made of tungsten or a high melting point metal. 14. The freeze valve of clause 1 further comprising a temperature controller in thermal communication with the valve body, the temperature controller being configured to adjust the temperature of the target material within the axial opening within a temperature range including the freezing point and melting point of the target material, thereby adjusting the flow of the target material through or within the axial opening. 15. The freeze valve of claim 1, wherein each gap between the wire and the inner surface of the valve body has an area less than or equal to the area of the region formed between the strands of the wire along a direction perpendicular to the axial direction. 16. The freeze valve of claim 1, wherein the axial opening includes a small-diameter axial opening adjacent to the primary axial opening, the wire is disposed within the primary axial opening, and the solid-state target material is formed within the small-diameter axial opening when the temperature of the target material is maintained below its freezing point. 17. The freeze valve of claim 1, wherein the wire includes a first wire and a second wire arranged in series within the axial opening of the valve body, and each of the first wire and the second wire includes a plurality of strands that define a plurality of continuous fluid paths passing through the axial opening of the valve body. 18. The freeze valve of claim 17, wherein the strands of the first wire are arranged in a spiral within the axial opening to define a first spiral path passing through the axial opening, and the strands of the second wire are arranged in a spiral within the axial opening to define a second spiral path passing through the axial opening. 19. The freeze valve of claim 1, wherein the strands of the plurality of strands are arranged linearly within the axial opening, and the continuous fluid path is a linear path passing through the axial opening. 20. The freeze valve of claim 1, wherein the axial opening of the valve body includes a first step feature and a second step feature, and the wire is attached between the first step feature and the second step feature. 21. An ejection nozzle in fluid communication with at least one target material reservoir, and at least one freeze valve in fluid communication with a fluid path defined between the ejection nozzle and the at least one target material reservoir, the target generator comprising: a valve body defining an axial opening extending along an axial direction; a wire within the axial opening of the valve body, the wire including a plurality of strands that define a plurality of continuous fluid paths passing through the axial opening of the valve body; and the target generator comprising the same. 22. The target generator of clause 21, wherein the valve body has a cylindrical shape. 23. The target generator of clause 21, wherein the freeze valve comprises a fluid port fluidly coupled to a gas source during a purge operation. 24. The target generator of clause 23, wherein the freeze valve comprises a second fluid port in fluid communication with a fluid path defined between an exit nozzle and at least one target material reservoir. 25. The target generator of clause 21, wherein the freeze valve comprises first and second fluid ports interposed between an exit nozzle and at least one target material reservoir. 26. The target generator of clause 21, further comprising a target material within a fluid path defined between an exit nozzle and at least one target material reservoir. 27. The target generator of clause 26, wherein the freeze valve, during operation of the exit nozzle, maintains a solid target material within a small-diameter axial opening of the axial opening at a temperature below its freezing temperature, such that the solid target material within the small-diameter axial opening becomes a stop mechanism configured to reduce or prevent a flow of material through a primary axial opening of the axial opening, and the primary axial opening is adjacent to the small-diameter axial opening, and the freeze valve comprises a temperature controller configured to maintain this state. 28. The target generator of clause 26, wherein the target material comprises tin, the valve body of the freeze valve is made of molybdenum or a high-melting-point metal, and the strand is made of tungsten or a high-melting-point metal. 29. A method of controlling a fluid, comprising: preventing a frozen target material from being axially extruded through a plurality of regions formed from a wire strand of a wire attached within a primary axial opening of a valve body having a diameter larger than that of a small-diameter axial opening when an axial pressure in the range of 10,000 to 765,000 PSI is applied to the frozen target material by freezing the target material within the small-diameter axial opening of the valve body of the freeze valve; thawing the target material within the small-diameter axial opening of the valve body of the freeze valve; and After thawing, enabling fluid to flow through one or more regions of the valve body of the freeze valve in the primary axis direction opening and the minor axis direction opening A method including this 30. The method of clause 29, after thawing, enabling fluid to flow through a region where the lateral spread between the strands of the wire is in the range of 2.0 to 0.5 mm at a conductivity of 0.03 to 0.001 L / second 31. The method of clause 29, enabling fluid to flow through one or more regions of the valve body of the freeze valve in the primary axis direction opening and the minor axis direction opening, including enabling purge gas to enter the primary axis direction opening from the gas source and flow through the primary axis direction opening 32. The method of clause 31, further including applying pressure to the purge gas while enabling the purge gas to flow, and pushing back the liquid target material existing inside and outside the primary axis direction opening and the minor axis direction opening to the target material reservoir

[0063]

[0077] The above examples and other examples are within the scope of the following claims

Claims

1. A valve body defining an axial opening extending along an axial direction, and a wire within the axial opening of the valve body, the wire including a plurality of strands defining a plurality of continuous fluid paths passing through the axial opening of the valve body A freeze valve provided with.

2. The freeze valve according to claim 1, wherein the valve body has a cylindrical shape.

3. The freeze valve according to claim 1, wherein the wire is configured to prevent a solid material from being extruded from the axial opening at a pressure exceeding 10,000 PSI, 20,000 PSI, 30,000 PSI, 100,000 PSI, 200,000 PSI, 300,000 PSI, 400,000 PSI, 500,000 PSI, 600,000 PSI, 700,000 PSI, or 725,000 PSI.

4. The freeze valve according to claim 1, wherein the strands of the plurality of strands are spirally arranged within the axial opening, and the continuous fluid path is a spiral path passing through the axial opening.

5. The freeze valve according to claim 1, wherein each strand has a diameter in the range of 0.2 to 0.3 millimeters (mm), and the diameter of the wire is in the range of 4 to 6 mm.

6. The region between the plurality of strands is from 0.785 to 7.069 mm ２ The freeze valve according to claim 5, having a cross-sectional area of

7. The freeze valve according to claim 1, wherein the axial opening of the valve body is defined by a constant diameter along the length of the wire.

8. The freeze valve according to claim 7, wherein the axial opening of the valve body includes a step feature, and the wire is attached between a fixed stop at a first end of the wire and the step feature at a second end of the wire.

9. The freeze valve according to claim 8, wherein the fixed stop includes a solid disk having a central axial opening, the central opening having a diameter smaller than an outer diameter of the wire, and an outer diameter of the solid disk being larger than the outer diameter of the wire.

10. The freeze valve according to claim 9, wherein the central axial opening of the fixed stop is fluidly coupled to a gas source.

11. The freeze valve according to claim 9, wherein the fixed stop further includes a fixed stop body extending from the solid disk into the axial opening of the valve body, the fixed stop body having a central opening that is in fluid communication with the central opening of the solid disk and also in fluid communication with the axial opening of the valve body.

12. The freeze valve according to claim 8, further comprising a first fluid port and a second fluid port defined in the fixed stop, wherein the axial opening includes a primary axial opening between the fixed stop and the step feature, and a small-diameter axial opening between the step feature and the second fluid port, and the primary axial opening has a diameter larger than the diameter of the small-diameter axial opening.

13. The freeze valve according to claim 1, wherein the valve body is made of molybdenum or a high melting point metal, and the plurality of wire strands are made of tungsten or a high melting point metal.

14. The freeze valve according to claim 1, further comprising a temperature controller in thermal communication with the valve body, the temperature controller being configured to adjust the temperature of the target material in the axial opening within a temperature range including the freezing point and melting point of the target material, thereby adjusting the flow of the target material through or within the axial opening.

15. The freeze valve according to claim 1, wherein each gap between the wire and the inner surface of the valve body has an area not greater than the area of the region formed between the strands of the wire along a direction perpendicular to the axial direction.

16. The freeze valve according to claim 1, wherein the axial opening includes a small-diameter axial opening adjacent to the primary axial opening, the wire is disposed within the primary axial opening, and a solid-state target material is formed within the small-diameter axial opening when the temperature of the target material is maintained below the freezing point of the target material.

17. The freeze valve according to claim 1, wherein the wire includes a first wire and a second wire arranged in series within the axial opening of the valve body, and each of the first wire and the second wire includes a plurality of strands defining a plurality of continuous fluid paths through the axial opening of the valve body.

18. The freeze valve according to claim 17, wherein the strands of the first wire are arranged in a spiral within the axial opening to define a first spiral path through the axial opening, and the strands of the second wire are arranged in a spiral within the axial opening to define a second spiral path through the axial opening.

19. The freeze valve of claim 1, wherein the strands of the plurality of strands are linearly arranged within the axial opening, and the continuous fluid path is a straight path passing through the axial opening.

20. The freeze valve of claim 1, wherein the axial opening of the valve body includes a first step feature and a second step feature, and the wire is attached between the first step feature and the second step feature.

21. An emission nozzle in fluid communication with at least one target material reservoir, A target generator comprising at least one freeze valve in fluid communication with a fluid path defined between the emission nozzle and the at least one target material reservoir, wherein the freeze valve A valve body defining an axial opening extending along an axial direction, A wire within the axial opening of the valve body, the wire including a plurality of strands defining a plurality of continuous fluid paths passing through the axial opening of the valve body A target generator comprising.

22. The target generator of claim 21, wherein the valve body has a cylindrical shape.

23. The target generator of claim 21, wherein the freeze valve includes a fluid port fluidly coupled to a gas source during a purge operation.

24. The target generator of claim 23, wherein the freeze valve includes a second fluid port fluidly communicating with the fluid path defined between the emission nozzle and the at least one target material reservoir.

25. The target generator of claim 21, wherein the freeze valve includes first and second fluid ports interposed between the emission nozzle and the at least one target material reservoir.

26. The target generator of claim 21, further including a target material within the fluid path defined between the emission nozzle and the at least one target material reservoir.

27. The freeze valve is configured to maintain the target material within the small-diameter axial opening of the axial opening at a temperature below its freezing temperature during operation of the emission nozzle, so that the solid target material is maintained as a stop mechanism configured to reduce or prevent the flow of the material through the primary axial opening of the axial opening within the small-diameter axial opening. The target generator of claim 26, wherein the primary axial opening is adjacent to the small-diameter axial opening.

28. The target generator of claim 26, wherein the target material includes tin, the valve body of the freeze valve is made of molybdenum or a high melting point metal, and the strand is made of tungsten or a high melting point metal.

29. A method of controlling a fluid, comprising: preventing the frozen target material from being axially extruded through a plurality of regions formed from wire strands of a wire attached within a primary axial opening of the valve body having a diameter larger than the small-diameter axial opening when an axial pressure in the range of 10,000 to 765,000 PSI is applied to the frozen target material by freezing the target material within the small-diameter axial opening of the valve body of the freeze valve; thawing the target material within the small-diameter axial opening of the valve body of the freeze valve; and after thawing, enabling fluid to flow through one or more of the regions of the primary axial opening and the small-diameter axial opening of the valve body of the freeze valve. A method comprising the steps of:

30. The method of claim 29, wherein after thawing, the fluid is enabled to flow through the region where the lateral spread between the strands of the wire is in the range of 2.0 to 0.5 mm at a conductivity of 0.03 to 0.001 L / second.

31. The method of claim 29, wherein enabling the fluid to flow through one or more of the regions of the primary axial opening and the small-diameter axial opening of the valve body of the freeze valve includes enabling purge gas to enter the primary axial opening from a gas source and flow through the primary axial opening.

32. The method of claim 31, further comprising applying pressure to the purge gas while allowing the purge gas to flow, to push back the liquid target material present inside and outside the primary axis direction opening and the small diameter axis direction opening into the target material reservoir.

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