KR20200133740A - Apparatus and method for controlling debris in EV light source - Google Patents

Abstract

An EUV system is disclosed that includes means for accumulating target material debris in liquid form, the target material being prevented from splashing onto the optics, the target material being able to solidify, and then melting to contaminate the collector. It is delivered to a location that can be discharged without.

Description

Apparatus and method for controlling debris in EV light source

The present invention claims priority to U.S. application 62/648,505, filed March 27, 2018, which is incorporated herein by reference in its entirety.

The present disclosure relates to an apparatus and method for generating extreme ultraviolet ("EUV") radiation from a plasma generated through laser ablation or discharge of a target material in a vessel. In these applications, optical elements are used to collect and guide radiation, for example used in semiconductor photolithography and inspection.

Extreme ultraviolet radiation, e.g., electromagnetic radiation (sometimes referred to as soft x-rays) including radiation having a wavelength of less than approximately 50 nm and a wavelength of approximately 13.5 nm, is used to create extremely small features in a substrate such as a silicon wafer. Used in photolithography processes.

A method for generating EUV radiation includes converting the target material to a plasma state. The target material preferably comprises at least one element having at least one emission line in the EUV portion of the electromagnetic spectrum, such as xenon, lithium or tin. The target material can be solid, liquid or gas. In one such method (often referred to as laser generated plasma (“LPP”)), the required plasma can be generated using a laser beam that irradiates the target material with the required prior-emitting element.

One LPP technique involves generating a stream of target material droplets and irradiating at least a portion of the droplets with one or more laser radiation plasmas. Such an LPP source connects laser energy to a target material having at least one EUV emitting element to generate a highly ionized plasma with an electron temperature of several tens of eV to generate EUV radiation.

For these processes, plasma is typically generated in a sealed vessel, such as a vacuum chamber, and the resulting EUV radiation is monitored using various types of metrology equipment. In addition to the generation of EUV radiation, the process used to generate the plasma also typically generates undesirable by-products within the plasma chamber, such as out-of-band radiation, high energy ions and debris (e.g., Atoms and/or lumps/fine droplets of residual target material).

Energy radiation is emitted from the plasma in all directions. In one typical configuration, a near-normal incidence mirror (often referred to as a "collector mirror" or simply "collector") is positioned to collect at least a portion of the radiation, guide it to an intermediate position and, in some configurations, focus. Let it. The collected radiation is delivered from an intermediate location to a set of optics, reticles, detectors, and finally to a silicon wafer.

In the EUV portion of the spectrum, this is generally considered necessary to use reflective optics for optical elements in systems including collectors, illuminators and projection optics boxes. These reflective optical instruments can be implemented as normal incidence optical instruments as mentioned or as grazing incident optical instruments. At the wavelengths involved, the collector can advantageously be implemented as a multilayer mirror ("MLM"). As his name suggests, these MLMs are typically made up of alternating layers of material (MLM stacks) on the base or substrate. The system optics can also be configured as a coated optical element even if not implemented as an MLM.

The optical element and in particular the collector must be placed inside the vessel with the plasma to collect and redirect EUV radiation. The environment inside the chamber is detrimental to the optical element, so for example deteriorating the reflectivity, limiting its service life. Optical elements inside the environment can be exposed to high energy ions or particles of the target material. Particles of the target material (essentially debris from the laser evaporation process) can contaminate the exposed surface of the optical element. Particles of the target material can also cause localized heating and physical damage to the MLM surface.

In some systems, H ₂ gas at a pressure of about 0.5 to about 3 mbar is used as a debris buffer gas in a vacuum chamber. In the absence of gas, under vacuum pressure, it will be difficult to adequately protect the collector from the target material debris released from the irradiation area. Hydrogen passes through EUV radiation with a wavelength of about 13.5 nm, for example, and is thus preferred over other candidate gases such as He, Ar or other gases that exhibit higher absorption at about 13.5 nm.

H ₂ gas is introduced into the vacuum chamber to slow down the energy debris (ions, atoms, and clusters) of the target material generated by the plasma. The debris is slowed down by collision with gas molecules. For this purpose, a flow of H ₂ gas is used, which flow can oppose the debris trajectory and can also be directed away from the collector. This serves to reduce damage to the target material for deposition, implantation and sputtering of the collector's optical coating.

Also, one of the most difficult problems with sources as described above is the management of residual target material. By the process of converting the target material into steam and particles, residual target material is deposited on all surfaces that have a path between the irradiation site and the surface and an unobstructed path to the discharge path of the gas accompanying the residual target material. For example, when this gas is pumped by a mechanical pump across the top of a vane present in the chamber, material is soon deposited on all the cold metal parts. If the target material is tin, this can cause the growth of tin wool, which can fall onto the collector optics and block the discharge path.

When tin is still used as an example of the target material, one technique for controlling tin dispersion involves trapping the tin from steam or particles onto a surface that is heated above the melting point of the tin. At its surface, the tin melts (or remains molten) and flows into the capture receptacle. However, liquid tin tends to spurt or “splash” in the presence of hydrogen radicals as seen in EUV chambers, and this released tin can hit the collector. This greatly contributes to collector deterioration. Second, liquid tin generally does not flow as intended. For example, structures inside the chamber, such as vanes and gutters for scrubbers, provided to remove some or all of the tin vapors in the chamber, may drop liquid tin onto the collector. In addition, the scrubber gutter can overflow and the liquid tin can flow down along the back of the vane, creating a thermal short (i.e., an unintended heat conduction path) and also obstructing the flow path to the capture receptacle. Additionally, liquid tin is highly corrosive and can cause failure of electric heaters used, for example, to keep the collecting surface above the melting point of tin. In addition, due to the flow constraints due to the tin accumulation, the gas takes a path through the smaller spaces in the vanes and collectors, thereby greatly increasing the collector deterioration due to tin deposition.

As mentioned, a scrubber can be added to the same area as the top of the vane, allowing entrained tin to precipitate out of the vapor and trap the tin. The scrubber surface remains above the melting point of the tin, allowing liquid tin to flow down the vane and into the receptacle. However, liquid tin in the scrubber can still splash onto the collector and fall from the gutter back onto the collector, thus increasing the collector deterioration. It is also difficult to keep the scrubber above the melting point of tin. If the temperature of the scrubber is lower than the melting point of the tin, the tin can solidify and clog the scrubber. For example, changing the size and inclination of the scrubber vanes can improve the performance by changing the geometry of the scrubber, but it cannot completely eliminate the scrubber's tendency to bounce on the collector or onto a cold surface to prevent discharge.

The process of generating EUV light can cause the target material to deposit on the walls of the vessel. Controlling the deposition of the target material on the vessel wall is important in obtaining an acceptable longevity of the EUV source deployed in manufacturing. In addition, management of the target material flux coming from the irradiation site is important to ensure that the waste target material abatement system is operating as intended.

Hereinafter, a brief summary of one or more embodiments is given to provide a basic understanding of the embodiments. This summary is not an extensive overview of all contemplated embodiments, nor is it intended to present key or important elements of all embodiments, nor to limit the scope of all embodiments or any of them. Its sole purpose is to present some concepts of one or more embodiments in a simplified form as a prelude to the more detailed description that is presented later.

In one aspect, different annotation management techniques are used for different portions of the "tin path", ie the path from the chamber liner to the imaging relay mirror that redirects light leaving the chamber. A combination of crude and liquid tin technology is used in conjunction with an exhaust manifold to manage the distribution and collection of tin. The regions of the effluent stream are identified, and an appropriate technique for handling the effluent gas stream is used in each of these regions based on its different requirements.

According to another aspect of the embodiment, an apparatus for generating EUV radiation is disclosed, the apparatus comprising: a container; Residual target material collection surface-the residual target material collection surface is occluded from the inside of at least a portion of the wall of the vessel and a first location where the residual target material collection surface is arranged to collect residual target material from the irradiation area. Having a second position, wherein the residual target material collecting surface at the second position is arranged to release the residual target material collected at the first position; And a temperature controller arranged to maintain the residual target material collection surface at the first position below the melting temperature of the target material and at the second position above the melting temperature of the target material. The residual target material collection surface may comprise the surface of the belt. The belt can be cooled in the first position and heated in the second position. The apparatus may further comprise at least one scrubber positioned adjacent the belt in the second position and arranged to remove residual target material from the belt. At least one scrubber may be positioned such that residual target material removed from the belt flows into the receptacle by gravity. The apparatus may further include a chamber discharge manifold in fluid communication with the chamber. The chamber discharge manifold has a liner, and at least a portion of the liner can be heated. The residual target material collection surface may include a shield. The shield may be cooled in the first position and heated in the second position. The shield may be arranged to pivot from the first position to the second position. The shield may be disposed to move from the first position to the second position laterally. The second position can be selected so that the molten residual target material flows from the shield to the receptacle by gravity. The apparatus may further include a chamber discharge manifold in fluid communication with the chamber. The chamber discharge manifold has a liner, at least a portion of which can be heated.

According to one aspect of the embodiment, a method for controlling residual target material in an apparatus for generating EUV radiation is disclosed, the method comprising: accumulating residual target material on a surface in a first location, the surface At a temperature below the melting temperature of the target material -; Moving the surface to a second position where the surface is at a temperature higher than the melting temperature of the residual target material to melt the residual target material; And removing the molten residual target material from the surface. Removing the molten residual target material from the surface may include scraping the molten residual target material from the surface. Removing molten residual target material from the surface may include allowing the molten residual target material to flow from the surface. After the removing step, there may be a step of allowing the removed molten residual target material to flow into the receptacle.

Further embodiments, features and advantages of the present invention, as well as the structure and operation of various embodiments, will be described in detail below with reference to the accompanying drawings.

FIG. 1 schematically illustrates an overall broad concept for a laser-generated plasma EUV radiation source system according to an aspect of the present invention, not to scale.
FIG. 2 is a diagram showing a possible configuration of a container and a discharge system used in a laser generated plasma EUV radiation source system according to an aspect of the present invention, without following the scale.
FIG. 3 is a diagram showing a possible configuration of a target material control system for a vessel used in a laser generated plasma EUV radiation source system in accordance with an aspect of the present invention, not to scale.
4A is a view showing a possible configuration of a target material control system for a neck portion of a container used in the laser-generated plasma EUV radiation source system according to an aspect of the embodiment of the present invention, without following a scale.
FIG. 4B is a diagram showing another possible configuration of a target material control system for the neck of a container used in the laser-generated plasma EUV radiation source system according to an aspect of the embodiment of the present invention, without following the scale.
FIG. 5A is a diagram showing other possible configurations of a target material control system for a neck portion of a container used in a laser generated plasma EUV radiation source system according to an aspect of the embodiment of the present invention, without following the scale.
5B is a top view of the configuration of FIG. 5A.
FIG. 6 is a diagram showing an additional element of a target material control system for a neck of a container used in a laser-generated plasma EUV radiation source system according to an aspect of the embodiment of the present invention, not to scale.

Additional features and advantages of the present invention and the structure and operation of various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the present invention is not limited to the specific embodiments described herein. Such embodiments are given here for illustrative purposes only. Additional embodiments based on the teachings contained herein will be apparent to those skilled in the art.

Hereinafter, various embodiments will be described with reference to the drawings, and the same reference numerals are used throughout to indicate the same elements. In the following description, for purposes of explanation, many specific details are given to facilitate a thorough understanding of one or more embodiments. However, in any case or in all cases, it is obvious that the embodiments described below may be practiced without adapting the specific design details described below. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing one or more embodiments.

However, before describing such an embodiment, it is educational to provide an example of an environment in which the embodiment of the present invention can be practiced. In the following description and claims, terms such as "top", "bottom", "top", "bottom", "vertical", "horizontal" and the like may be used. These terms, unless otherwise stated, refer to relative orientation and not to any orientation with respect to gravity.

Referring initially to FIG. 1, a schematic diagram of an exemplary EUV radiation source, eg, a laser generated plasma EUV radiation source 10, in accordance with an aspect of an embodiment of the present invention is shown. As shown, the EUV radiation source 10 may comprise a pulsed or continuous laser source 22, which laser source is a pulsed gas discharge that produces a radiation beam 12 of 10.6 μm or 1 μm, for example. It may be a CO ₂ laser source. This pulsed gas discharge CO ₂ laser source can have DC or RF excitation operating at high power and high pulse repetition rate.

The EUV radiation source 10 also includes a target delivery system 24 for delivering a target material in the form of droplets or a continuous liquid stream. In this example, the target material is a liquid, but may be a solid or a gas. The target material may be composed of tin or a tin compound, but other materials may be used. In the system shown, the target material delivery system 24 introduces a droplet 14 of target material into the interior of the vacuum chamber 26 into the irradiation area 28, where the target material is irradiated to generate a plasma. do. A liner may be provided in the vacuum chamber 26. In some cases, an electric charge can be placed on the target material, so that the target material can be steered towards or away from the irradiation area 28. As used herein, the irradiation area is an area in which target material irradiation may or is supposed to occur, even when irradiation does not actually occur. The EUV light source may include a beam steering system 32.

In the system shown, the components are arranged such that the droplet 14 moves substantially horizontally. The direction from the laser source 22 toward the irradiation area 28, that is, the nominal propagation direction of the beam 12 may be the Z axis. The path taken by the droplet 14 when traveling from the target material delivery system 24 to the irradiation area 28 may be the X axis. Thus, Fig. 1 is perpendicular to the XZ plane. The orientation of the EUV radiation source 10 is preferably rotated with respect to gravity as shown, and the tabulation G indicates the preferred orientation with respect to the lower gravity. This orientation corresponds to the EUV source, but does not necessarily correspond to an optically downstream element such as a scanner or the like. In addition, although a system is shown in which the droplet 14 moves substantially horizontally, those skilled in the art will know that the droplet may be at any angle to gravity vertically or between 90 degrees (horizontal) and 0 degrees (vertical) (including endpoints). It will be appreciated that other configurations to go to may also be used.

The EUV radiation source 10 may also include an EUV light source controller system 60, a laser emission control system 65 along with the beam steering system 32. EUV radiation source 10 may also comprise a detector, such as a target position detection system, which may include one or more droplet imagers 70, which imager is, for example, an absolute or Generates an output representative of the relative position and provides this output to the target position detection feedback system 62.

As shown in FIG. 1, the target material delivery system 24 may include a target delivery control system 90. The target delivery control system 0 operates in response to a signal, e.g., an amount obtained from the target error described above, or a target error provided by the system controller 60, to cause a target droplet 14 passing through the irradiation area 28. ) Can be adjusted. This can be achieved, for example, by repositioning the location where the target delivery mechanism 92 ejects the target droplet 14. The droplet ejection point can be repositioned, for example by tilting the target delivery mechanism 92 or translating the target delivery mechanism 92 laterally. The target delivery device 92 can extend into the chamber 26 and is preferably provided externally, a target material, and a gas source for placing the target material into the target delivery device 92 under pressure.

With continued reference to FIG. 1, the radiation source 10 may comprise one or more optical elements. In the discussion below, the collector 30 is used as an example of such an optical element, but the discussion also applies to other optical elements. The collector 30 may be a normal incident reflector, for example, having an additional thin barrier layer such as B ₄ C, ZrC, Si ₃ N ₄ or C disposed at each interface to effectively prevent thermally induced interlayer diffusion. It can be implemented with MLM. Other substrate materials such as aluminum (Al) or silicon (Si) may also be used. The collector 30 may be an oblong oval, and has a central hole that allows the laser radiation 12 to pass through and reach the irradiation area 28. The collector 30 may be, for example, in the form of an ellipse having a first focal point in the irradiation area 28 and a second focal point in the so-called midpoint 40 (also referred to as the middle focal point 40), EUV radiation It can be output from EUV radiation source 10 and input to an integrated circuit lithography scanner 50, for example, which scanner uses a reticle or mask 54 in a well-known manner using radiation, for example, using a silicon wafer workpiece ( 52). The silicon wafer workpiece 52 is further processed in a known manner to obtain an integrated circuit device.

The configuration of FIG. 1 also includes a temperature sensor 34, eg, a thermocouple, positioned inside the chamber 26 to measure the local temperature of the gas inside the chamber 26, ie the temperature at the sensor. 1 shows one temperature sensor, it will be apparent that additional temperature sensors could be used. The temperature sensor 34 generates a signal indicative of the measured temperature and supplies the signal to the controller 60 as an additional input. The controller 60 is based at least in part on the control signal it supplies to the beam steering system 32 on this temperature signal.

The buildup of target material debris on the container directly above the collector causes the target material to fall onto the collector. The solid double arrows in the figure indicate the direction of debris propagation. The outline arrows indicate a preferred arrangement for allowing H ₂ to flow in a direction away from the collector 30. Element 42 is a scrubber for removing contaminants from H ₂ . Arrow G indicates the direction of gravity. Also shown is a line 13 indicating the deviation between the source 10 and the scanner 50.

3 shows a chamber design with an asymmetrical outlet with a large neck area. The design of FIG. 3 has two discharge ports 60. In this design, a large amount of tin can be deposited at a location 70 on the wall of the exhaust manifold opposite this large neck. If this surface is kept at a temperature higher than the melting point of tin, the molten tin can splash onto the coltector.

In a system according to one aspect of the embodiments of the present invention, the tin is melted or maintained in a liquid state at a location where liquid tin cannot or is unlikely to splash into the interior of the chamber or onto the collector. High flow conductivity can be maintained and the exhaust gas is scrubbed. According to another aspect, tin can be ejected to its original location when the source is running.

An example of such a system is shown in FIG. 4A. Debris from the irradiation area 28 is captured by the two heated scrubbers 80. These scrubbers 80 are in each of the hot areas completely shielded from splashing back into the inner surface 84 of the chamber 26, including onto the liner 84 that at least partially covers the discharge plenum wall 86. Is located. The portion 88 of the liner 84 adjacent the scrubber 80 may be heated to a temperature above its melting point to "drop off" excess solid tin. These surfaces are again shielded from splashing on the collector.

Also as shown in FIG. 4A, the configuration includes an endless belt 90 that covers the rear portion of the discharge plenum or a portion of the outer wall 94. Between these belts 90, there is a low temperature (e.g., water cooling) plate 92 (which is in contact with or almost in contact with the belt) to keep the surface sufficiently below the melting point of tin. Thus, solid tin particles impinging on this area will remain in a solid state, and tin vapors impinging on this area will become solid.

Belt 90 may be continuously, intermittently moved, or periodically ratcheted forward to deliver solid tin to the hot scrubber 80. When the endless belt 90 meets the hot scrubber 80, there may be a heated doctor blade that melts the tin and scratches the belt 90 cleanly, so the belt 90 is a sediment area ready to collect more tin. Will return to With this configuration, the tin will not be able to bounce onto the collector or liner. The belt 90 is preferably placed in an area where a maximum amount of tin deposits can be expected, for example in the neck area.

Another example of such a system is shown in FIG. 4B. Here, too, tin debris from irradiation area 28 is captured by two heated scrubbers 80 located on the inner surface 84 of the liner 86 and in each of the hot areas completely shielded from splashing back into the collector. do. As shown in Fig. 4B, the configuration includes a wedge-shaped diverter 96 located on the wall of the discharge plenum at the neck outlet. By means of the direction changer 96, debris emerging from the irradiation area 28 (open arrow) flows into a portion of the discharge manifold shielded from the irradiation area 28 (curved arrow). The splash direction of entrained/deposited molten tin tends to point towards the scrubber 80 and does not return into the interior of the vacuum vessel. The diverter 94, in its shape, guides the flow of exhaust gases and entrained debris more directly into the scrubber away from the rear wall at the exit of the neck. The diverter 96 is typically cooled below the melting point of the target material, but is heated above the tin melting temperature, allowing the accumulated solid tin on the diverter 96 to flow away and descend down the tin outlet. . Tin mostly bounces perpendicular to the surface of the diverter 96, which faces away from the interior of the chamber 26, thus greatly limiting the amount of bounce that can go to the tool's optics.

Care should be taken in the roof section of the liner in the opening to the large neck. These roof and floor areas will typically be inclined and concave to protect the collector/liner as much as possible.

Other areas of high deposit can be covered with a hinged water-cooled shield so that it can rotate behind the opening for fall off. This configuration is shown in Figures 5A and 5B. 5A shows a neck region having a shielding portion 110. The shield 110 is connected to the wall of the neck with a hinge 112 so that the shield can be pivoted behind the opening to a position (shown by a virtual line) where the shield can be heated and tin can fall off. 5B is a top view of the configuration of FIG. 5A showing the rotation of the shield 110 around the hinge 112. These shields 110 can be positioned to minimize adverse effects on conductivity, so splashing liquid tin does not have a clear path to the collector or liner.

Nevertheless, variations to the above-described embodiment that maintain the spirit of the present disclosure are possible. According to one aspect of the disclosed embodiment, a solid tin temperature surface is provided in the area that can splash into the liner and collector. The tin can then be removed in one of several ways, including cycling the surface's temperature, ie, temporarily raising the temperature of the surface above the melting point of the tin. Alternatively or additionally, the surface may be moved to a shielding position for dropping or may be covered during dropping. In another embodiment, liquid tin is recovered (scrubbed) from the gas stream and delivered to a suitable isolated location for discharge (eg, not going in an apparent path to the collector or liner). The wall upstream of the scrubber can be maintained at a temperature that allows tin to fall from the wall. According to another aspect, for areas of very high deposition, temperature cycling, moving the liner portion to a safe position for dropping, ion generation to purify and keep clean, or partial cover during dropping may be used.

6 shows an embodiment in which the neck 100 is moved to the highest possible position of the chamber to limit the amount of debris overshoot between the plasma on state and the plasma off state, ie when plasma is generated or not. This increases the efficiency of debris discharge and limits the amount of debris deposited on the inner wall surface. In this embodiment, the endless belt 90 of the embodiment of FIG. 4A may be used, or a heated plate may be placed at the output of the neck 100. The discharge manifold can be made circular (tubular) and thus have a round scrubber 110 instead of a rectangular scrubber. The tin discharge unit 115 collects molten tin and sends it to a tin bucket or receptacle 117. The cooling valve 119 allows the discharge of the tin receptacle 117 through the conduit 121 without interrupting the operation of the source. The tin outlet may be disposed on both sides of the source.

The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of elements or methods for describing the above-mentioned embodiments, but those skilled in the art will recognize that many combinations and substitutions of various embodiments are possible. Accordingly, the described embodiments include all such changes, modifications and changes included in the appended claims and the spirit thereof. Also, to the extent that the term "comprises" is used in the detailed description or claims, such terms are, as interpreted when "comprising" is used as a transition phrase in the claims, similarly to the term "comprising" will be. In addition, although elements of the above-described aspects and/or embodiments are described or claimed in the singular form, they should be considered as plural unless the limitation to the singular is clearly stated. Additionally, unless otherwise stated, all or part of an aspect and/or embodiment may be used in conjunction with all or part of another aspect and/or embodiment.

Other aspects of the invention are shown in the following numbered paragraphs.

1. As a device for generating EUV radiation,

Vessel;

Residual target material collection surface-the residual target material collection surface is occluded from the inside of at least a portion of the wall of the vessel and a first location where the residual target material collection surface is arranged to collect residual target material from the irradiation area. Having a second position, wherein the residual target material collecting surface at the second position is arranged to release the residual target material collected at the first position; And

And a temperature controller arranged to keep the residual target material collection surface below the melting temperature of the target material in the first position and above the melting temperature of the target material in the second position to generate EUV radiation. Device.

2. The apparatus of claim 1, wherein the residual target material collection surface comprises a surface of a belt.

3. The apparatus of clause 2, wherein the belt is cooled in the first position and heated in the second position.

4. The apparatus of claim 2, further comprising at least one scrubber positioned adjacent the belt in the second position and arranged to remove residual target material from the belt.

5. The apparatus of claim 4, wherein the at least one scrubber is positioned such that residual target material removed from the belt flows into the receptacle by gravity.

6. The apparatus of claim 1, further comprising a chamber discharge manifold in fluid communication with the chamber.

7. The apparatus of claim 6, wherein the chamber discharge manifold has a liner, wherein at least a portion of the liner is heated.

8. The apparatus of claim 1, wherein the residual target material collection surface comprises a shield.

9. The apparatus of claim 8, wherein the shield is cooled in the first position and heated in the second position.

10. The apparatus of claim 8, wherein the shield is arranged to pivot from the first position to a second position.

11. The apparatus according to claim 8, wherein the shield is arranged to move laterally from the first position to a second position.

12. The apparatus of claim 8, wherein the second position is selected to cause molten residual target material to flow from the shield to the receptacle by gravity.

13. The apparatus of clause 8, further comprising a chamber discharge manifold in fluid communication with the chamber.

14. The apparatus of claim 13, wherein the chamber discharge manifold has a liner, at least a portion of which is heated.

15. As a method for controlling residual target material in a device for generating EUV radiation,

Accumulating residual target material on a surface at a first location, the surface being at a temperature below the melting temperature of the target material;

Moving the surface to a second position such that the surface is at a temperature higher than the melting temperature of the residual target material to melt the residual target material; And

A method for controlling residual target material in an apparatus for generating EUV radiation comprising the step of removing molten residual target material from the surface.

16. The method of 15, wherein removing the molten residual target material from the surface comprises scraping the molten residual target material from the surface.

17. The method of 15, wherein removing the molten residual target material from the surface comprises causing the molten residual target material to flow from the surface.

18. The method of 15, further comprising, after the removing step, flowing the removed molten residual target material into the receptacle.

Claims (18)

As a device for generating EUV radiation,
Vessel;
Residual target material collection surface-the residual target material collection surface is occluded from the inside of at least a portion of the wall of the vessel and a first location where the residual target material collection surface is arranged to collect residual target material from the irradiation area. Having a second position, wherein the residual target material collecting surface at the second position is arranged to release the residual target material collected at the first position; And
And a temperature controller arranged to keep the residual target material collection surface below the melting temperature of the target material in the first position and above the melting temperature of the target material in the second position to generate EUV radiation. Device. The method of claim 1,
Wherein the residual target material collection surface comprises a surface of a belt. The method of claim 2,
Wherein the belt is cooled in the first position and heated in the second position. The method of claim 2,
The apparatus further comprises at least one scrubber positioned adjacent the belt in the second position and arranged to remove residual target material from the belt. The method of claim 4,
Wherein the at least one scrubber is positioned such that residual target material removed from the belt flows into the receptacle by gravity. The method of claim 1,
The apparatus further comprising a chamber discharge manifold in fluid communication with the chamber. The method of claim 6,
Wherein the chamber discharge manifold has a liner and at least a portion of the liner is heated. The method of claim 1,
Wherein the residual target material collection surface comprises a shield. The method of claim 8,
Wherein the shield is cooled in the first position and heated in the second position. The method of claim 8,
Wherein the shield is arranged to pivot from the first position to a second position. The method of claim 8,
Wherein the shield is arranged to move laterally from the first position to a second position. The method of claim 8,
The second position is selected to allow molten residual target material to flow from the shield to the receptacle by gravity. The method of claim 8,
The apparatus further comprising a chamber discharge manifold in fluid communication with the chamber. The method of claim 13,
Wherein the chamber discharge manifold has a liner and at least a portion of the liner is heated. A method for controlling residual target material in an apparatus for generating EUV radiation, comprising:
Accumulating residual target material on a surface at a first location, the surface being at a temperature below the melting temperature of the target material;
Moving the surface to a second position such that the surface is at a temperature higher than the melting temperature of the residual target material to melt the residual target material; And
A method for controlling residual target material in an apparatus for generating EUV radiation comprising the step of removing molten residual target material from the surface. The method of claim 15,
Wherein removing the molten residual target material from the surface comprises scraping the molten residual target material from the surface. The method of claim 15,
Wherein removing the molten residual target material from the surface comprises causing the molten residual target material to flow from the surface. The method of claim 15,
After the removing step, the method further comprising the step of allowing the removed molten residual target material to flow into the receptacle.

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