Vertical Rotary Metal Bellows for Rotary Motion, Vacuum Sealing, and Pressure Sealing

Abstract

A system and method for rotational motion with a vacuum seal is provided. The system includes a vacuum chamber, a part mount disposed within the vacuum chamber, and a base. A bellows is disposed between the base and the part mount, the bellows providing a seal between the base and the part mount. The bellows, base, and part mount define an actuator compartment therebetween. An actuator is disposed within the actuator compartment. The actuator is configured to rotate the part mount relative to the base to align a part disposed on the part mount. Rotation of the part mount relative to the base causes a torsional elastic deformation of the bellows.

Description

Technical Field

[0001] The present disclosure relates to an optical instrument for semiconductor inspection or measurement.

Background Art

[0002] Reference to Related Applications This application claims priority to U.S. Provisional Patent Application 63 / 151,800, filed February 22, 2021 and assigned, the disclosure of which is incorporated herein by reference.

[0003] The evolution of the semiconductor manufacturing industry has placed greater demands on yield management, particularly on metrology and inspection systems. Critical dimensions continue to shrink, but the industry needs to reduce the time to achieve high yields and high-value production. Minimizing the total time from detecting a yield problem to fixing it determines the return on investment for semiconductor manufacturers.

[0004] Manufacturing semiconductor devices, such as logic devices and memory devices, typically involves processing semiconductor wafers using a number of manufacturing processes to form various features and multiple levels of the semiconductor device. For example, lithography is a semiconductor manufacturing process that involves transferring a pattern from a reticle to a photoresist disposed on a semiconductor wafer. Further examples of semiconductor manufacturing processes include, but are not limited to, chemical mechanical polishing (CMP), etching, deposition, and ion implantation. An array of multiple semiconductor devices fabricated on a single semiconductor wafer can be separated into individual semiconductor devices.

[0005] The continuous shrinking of design geometries in integrated circuit devices creates a continuous need for improved optical inspection and metrology tools. For example, the light sources for photolithography systems have historically evolved to ever smaller wavelengths, thereby enabling the construction of ever smaller structures. For example, the use of visible wavelength light (e.g., 400 nm) led to a shift to near ultraviolet light (e.g., 300 nm), which in turn led to a shift to deep ultraviolet (DUV) light (e.g., 200 nm). More recently, DUV light sources have opened the way to extreme ultraviolet (EUV) sources (e.g., 13.5 nm).

[0006] As feature sizes in semiconductor technology become ever smaller, the wavelength of light has become a limiting factor in optical processes used in semiconductor processes, including lithography, as well as the inspection and metrology of wafers and masks. Advanced optical technologies use EUV light (e.g., wavelengths in the range of 11 nm to 15 nm, more specifically a wavelength of 13.5 nm) to address problems caused by ever smaller feature sizes, and a bright EUV light source without debris is valuable in the pursuit of next-generation semiconductor processes. One difficult aspect of developing a bright EUV light source is to reduce debris from the plasma generation process while minimizing the loss of EUV light generated by the plasma.

[0007] One drawback of inspection tools operating in EUV is that particle protection devices such as pellicles commonly used in tools with longer wavelengths are opaque at EUV wavelengths and thus cannot be used in EUV setups. Furthermore, the critical dimensions of reticles intended to be inspected on EUV tools can be so small that almost all particles present on the reticle surface cause unacceptable problems. As an example, contaminant particles can emanate from nearby optical systems used to direct inspection light onto the reticle. In addition, the reticle stage used to move the reticle during inspection can also be a source of contaminant particles.

[0008] Furthermore, some of the optical systems in EUV or other vacuum environment inspection systems need to be actuated for alignment reasons. This requires precise (e.g., sub-nanometer) accurate movement for one or more degrees of freedom. Additionally, some optical systems are large (e.g., several kilograms) and require actuation force to move. These optical systems are moved in a vacuum. The exposed optical surfaces are sensitive to contamination from both volatile organic compounds (VOCs) and particles. VOCs can be contaminants. The actuators required to move the optical systems can degas volatile hydrocarbons. This actuation can generate particles that can land on critical surfaces within the system.

[0009] When alignment requires rotational movement of the optical system, a rotational seal is required. Typical elastomeric seals (e.g., O-rings, lip seals, etc.) can be used in low-vacuum applications but shed particles during rotation, allow gas to enter the sealed volume, and cause contamination. Ferrofluid seals are also not suitable for ultra-high vacuum applications.

[0010] Currently, particle control in optical-based reticle inspection systems is performed by an air flow that pushes particles in a known direction. In vacuum systems such as electron beam inspection systems, particle control is generally performed using a small amount of positive pressure and particle reduction methods designed to reduce the number of particles. Previous methods have several drawbacks. For example, they did not show the ability to remove particles up to 10 nm in diameter. Additionally, previous methods have only been used in processes that allow reticle cleaning after inspection. However, EUV reticle inspection tools cannot be cleaned after inspection and must therefore compete with smaller particles.

[0011] To separate a vacuum environment including an exhaust portion, differential pumping can be used. The vacuum regions to be differentially pumped require connection to a pumping system. This can be difficult to achieve for vacuum chambers within a larger assembly. Additionally, vacuum pumps can generate vibrations that are harmful to a precisely aligned optical system.

[0012] The cleaning process can reduce the outgassing rate from components. Most actuators contain lubricants or other materials that outgas and can never be completely reduced. Additionally, during movement, additional molecular and particulate contaminants are generated that cannot be completely removed by cleaning.

Prior Art Documents

Patent Documents

[0013]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0014] Therefore, an improved system and method for rotary seals in ultra-high vacuum are needed.

Means for Solving the Problems

[0015] Embodiments of the present disclosure provide a system. The system may include a vacuum chamber, a component mount disposed within the vacuum chamber, and a base. The system may further include a bellows disposed between the base and the component mount. The bellows, the base, and the component mount may define an actuator compartment therebetween. The bellows can provide a seal between the base and the component mount. The system may further include an actuator disposed within the actuator compartment. The actuator may be configured to rotate the component relative to the base. Rotation of the component mount relative to the base can cause torsional elastic deformation of the bellows.

[0016] According to embodiments of the present disclosure, the system can further include a first flange fixed to the first end of the base and the bellows. The first flange may be fixed to the first end of the bellows by circumferential welding. The system can further include a second flange fixed to the second end of the component mount and the bellows. The second flange may be fixed to the second end of the bellows by circumferential welding. At least one of the first flange and the second flange can include a seal ground, and a seal ring can be disposed within the seal ground.

[0017] According to embodiments of the present disclosure, the bellows can include a swivel section disposed between a first end section and a second end section. The swivel section may include vertical ribs extending from the first end section to the second end section. The perimeter of the swivel section may have a sinusoidal shape defined by the vertical ribs.

[0018] The bellows may be made of a nickel-cobalt alloy. The bellows can be manufactured by electroforming. The bellows may have a substantially circular cross-section.

[0019] According to an embodiment of the present disclosure, the system can further include an optical component disposed on a component mount within a vacuum chamber. Rotation of the component mount relative to the base can cause a corresponding rotation of the optical component.

[0020] Another embodiment of the present disclosure provides a method. The method may include providing a component mount within a vacuum chamber. The method may further include providing an actuator disposed between the component mount and the base. A bellows may be disposed between the base and the component mount. The bellows, the base, and the component mount may define an actuator compartment therebetween. The bellows can provide a seal between the base and the component mount. The method may further include using the actuator to rotate the component mount relative to the base. Rotation of the component mount relative to the base can cause torsional elastic deformation of the bellows.

[0021] According to an embodiment of the present disclosure, the method may further include electroforming a bellows structure on a mandrel. The method may further include removing the mandrel from the bellows structure to obtain the bellows. The method may further include disposing the bellows between the base and the component mount within the vacuum chamber.

[0022] To more fully understand the nature and objects of the present disclosure, reference should be made to the following detailed description in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2A

Figure 2B

Figure 3A

Figure 3B

Figure 3C

Figure 4A

Figure 4B

Figure 5A

Figure 5B

DETAILED DESCRIPTION OF THE INVENTION

[0024] The claimed subject matter is described with respect to certain embodiments, but other embodiments, including those that do not provide all of the benefits and features described herein, are also within the scope of the present disclosure. Various structural, logical, process step, and electronic changes may be made without departing from the scope of the present disclosure. Accordingly, the scope of the present disclosure is defined only by reference to the appended claims.

[0025] FIG. 1 is a cross-sectional view of a system 100. The system 100 includes a vacuum chamber 101. In one example, the vacuum chamber 101 is part of an EUV semiconductor inspection tool. The walls of the vacuum chamber 101 define an interior 102 that can be pumped down to a low or vacuum pressure by a vacuum pump 103. The vacuum pressure may be less than 10 -7 mbar. For example, the vacuum pressure can be at an ultra-high vacuum (UHV) level (e.g., between 10 -7 and 10 -12 mbar). The partial pressure of hydrocarbons can be less than 10 -10 mbar.

[0026] Component 105 can be arranged inside the vacuum chamber and held by component mount 110. Component 105 may be an optical component. The optical component can be, for example, a camera, a lens, a mirror, an aperture, a sensor, a filter, an attenuator, or a shutter. The optical component can be configured for use at EUV wavelengths. In another example, the optical component may be a mask. The mask may not include a pellicle, and thus even a single particle on the mask can mean an in-operation failure. Component 105 can be other components that are remotely actuated in vacuum, such as a stage. System 100 can include a plurality of component mounts 110 configured to hold different components 105 respectively. For example, system 100 may include a sensor array, and each sensor is held by a separate component mount 110.

[0027] EUV light or light of other wavelengths can be directed through component 105. There may be a light source inside vacuum chamber 101.

[0028] Component mount 110 can be connected to base 115. Bellows 120 can be arranged between base 115 and component mount 110. Bellows 120 can provide a seal between base 115 and component mount 110. This seal can provide protection on the order of several digits in molecules. For example, the seal can have a leak rate of less than 10 -11 standard cubic centimeters per second per meter of length. By using bellows 120, almost all particles of 10 nm or more can be contained.

[0029] Bellows 120, base 115, and component mount 110 can define an actuator compartment 111 therebetween. FIG. 1 is a cross-sectional view, and thus bellows 120 can extend around the entirety of base 115 and component mount 110 to seal actuator compartment 111. Bellows 120 may be connected to base 115 and component mount 110 using fasteners, welding, brazing, soldering, or other techniques.

[0030] In one example, the bellows 120 is made of a nickel-cobalt alloy. Other metals such as nickel, copper, or other alloys may be used. The bellows 120 can be made of any flexible material that is UHV compatible and can prevent the passage of most contaminants. The bellows 120 may be capable of withstanding the pressure difference between atmospheric pressure and UHV within the vacuum chamber 101 and the actuator compartment 111. The bellows 120 can withstand a larger pressure difference, for example, up to 3 atm to UHV.

[0031] The actuator 112 can be disposed within the actuator compartment 111. The actuator 112 may be configured to rotate the component mount 110 relative to the base 115. The actuator 112 may have a lubricant for operation, and any movement by the actuator 112 can generate particles and VOCs. The particles are typically made from materials within or around the vacuum chamber 101. For example, two components within the vacuum chamber 101 can rub against each other to form particles. The VOCs can be lubricants, cleaning agents, residues from a machine shop, or materials within the vacuum chamber 101.

[0032] Thus, particles can occur due to the shedding of material caused by some disturbance. The particles are generally made of the same materials as the actuator 112 (e.g., metal, plastic, and lubricant). These can be shredded material from two materials rubbing against each other, or the removal of loosely adhering material caused by movement and vibration (e.g., deposited particles, lubricants, etc.). Generally, anything that moves (e.g., the actuator 112) can generate particles. In addition, even static items can generate VOCs either as the material decomposes or as the attached volatile compounds evaporate by outgassing.

[0033] The lubricant generates degassing, which can occur from the material itself as it decomposes. For example, plastics can degas. Gas evolution can also occur from molecular contaminants adhering to a clean surface such as metal. The contaminants generally result from residual contamination during manufacturing.

[0034] The size of the particles can depend on which part moves, the material, or the surface finish. The particles can have a diameter of 5 nm or more, for example 10 nm or more.

[0035] Rotation of the component mount 110 relative to the base 115 can cause torsional elastic deformation of the bellows 120. By twisting the bellows 120, the component mount 110 can be rotated for alignment. For example, the component mount 110 may be rotated by 10 μrad or more relative to the base 115. The rotation range of the bellows 120 within the elastic deformation range and the force required to cause torsional elastic deformation can depend on the material, thickness, and geometry of the bellows 120 as well as the temperature and vacuum pressure within the vacuum chamber 101 and the actuator compartment 111. For example, the rotation range of the bellows 120 may be 1 - 10 μrad, 1 - 3 μrad, 1.3 - 3 μrad, 1.3 - 2 μrad, 2 - 3 μrad, or other ranges. In certain embodiments, the component mount 110 can rotate by approximately 2 μrad relative to the base 115. When the deformation of the bellows 120 is within the elastic range, rotation in the opposite direction can restore the bellows 120 to its original shape and the rotation can be repeated. When the deformation of the bellows 120 is in the inelastic range, the bellows 120 may not be able to return to its original shape, and such plastic deformation can break the seal of the actuator compartment 111 and may require replacement of the bellows 120.

[0036] Rotation of the component mount 110 relative to the base 115 can cause corresponding rotation of the component 105. This enables alignment of the component 105 and can improve the measurement accuracy of the system 100.

[0037] Figures 2A and 2B show bellows 120. The bellows 120 may include a swivel section 123. The swivel section 123 may be disposed between a first end section 121 and a second end section 122 of the bellows 120. The swivel section 123 may include vertical ribs 124 extending from a first end segment 121 to a second end segment 122. As shown in Figure 2B, the vertical ribs 124 may alternately project inwardly and outwardly from the bellows 120. For example, each inwardly projecting rib 124a may be disposed between two outwardly projecting ribs 124b. Each of the vertical ribs 124 may have a similar geometry. For example, each of the vertical ribs 124 may have a similar length, width, projection depth, and shape, the values of which may depend on the pressure load and rotation required for the bellows 120. According to a particular embodiment, the vertical ribs 124 may have a length of less than 1.77 inches, a width of about 0.25 inches, and a projection depth of about 0.125 inches. The vertical ribs 124 can have a semi-circular shape. Thus, the perimeter of the swivel section 123 may have a sinusoidal shape defined by the vertical ribs 124. The vertical ribs 124 may have other shapes, such as triangular, rectangular, etc.

[0038] The bellows 120 may have a substantially circular cross-section. The bellows 120 may have a diameter of about 7 inches and a height of about 1.77 inches. Alternatively, the bellows 120 may have a polygonal cross-section, such as square, hexagonal, etc. In such cases, the vertical ribs 124 may have different geometries, for example, at the corners of the cross-sectional shape. The bellows 120 can have a thickness of about 0.008 inches. A thinner thickness can be achieved by combining different layers of metal. For example, a copper layer used in combination with a nickel / cobalt layer can produce a bellows 120 with a thickness of 0.003 inches. The dimensions of the bellows 120 may depend on the required pressure load and rotation.

[0039] Generally, the design of bellows 120 can depend on system requirements, including the rotation range, pressure / vacuum requirements, geometric constraints, and operating forces. The design of bellows 120 can also depend on physical constraints, including material properties and manufacturing capabilities. Based on the balance between system requirements and physical constraints, specific values for each design variable can be selected. The design variables may include the geometry of the bellows (diameter, height, etc.), the geometry of the convolution section (height, radius, etc.), and the convolution thickness. Thus, bellows 120 can be used for various applications.

[0040] Bellows 120 can provide several advantages to system 100 compared to existing rotary seals. Bellows 120 may be UHV compatible and may be used in environments exposed to harsh radiation, chemical, or thermal conditions. Bellows 120 can be aggressively cleaned and, for example, returned to high temperatures above 400°C. Bellows 120 may not emit particles or outgas. Bellows 120 can be configured to support pressures above one atmosphere internally and externally. The size of bellows 120 can be scaled larger or smaller for use in inspection systems and applications having various sizes.

[0041] Bellows 120 can be formed using various manufacturing methods. According to an embodiment of the present disclosure, bellows 120 can be fabricated by electroforming. In an exemplary electroforming process shown in FIG. 3A, a solid metal source and a conductive mandrel are placed in an electrolyte containing a salt of the metal to be electroformed, and a direct current is applied to the metal source (anode) and the mandrel (cathode). The direct current causes the deposition of metal on the outer surface of the mandrel until a bellows structure having the required thickness is achieved. The outer surface of the mandrel has vertical ribs corresponding to the vertical ribs 124 of bellows 120, and thus, when metal is deposited on the outer surface of the mandrel, the resulting bellows structure has the same vertical ribs. The mandrel can be separated intact from the bellows structure, removed by melting, or chemically dissolved / etched to obtain bellows 120.

[0042] According to another embodiment of the present disclosure, the bellows 120 can be fabricated by a roll forming process. In the exemplary roll forming process shown in FIG. 3B, a metal sheet passes through one or more sets of rollers that form vertical ribs in the metal sheet. The metal sheet is then rolled into a cylindrical shape and welded to obtain the bellows 120.

[0043] According to another embodiment of the present disclosure, the bellows 120 can be fabricated by a hydroforming process. In the exemplary hydroforming process shown in FIG. 3C, a thin-walled tube is placed within a two-piece mold. The inner surface of the two-piece mold has vertical ribs corresponding to the vertical ribs 124 of the bellows 120. When fluid is pushed into the tube, the fluid pressure causes the tube to deform into the shape of the inner surface of the mold, obtaining the bellows 120. The fluid may be water, oil, or other liquid.

[0044] The bellows 120 can be formed using other manufacturing methods known in the art, and it should be understood that the present disclosure is not limited to the examples described herein. By these manufacturing methods, a monolithic thin bellows 120 having a vertical turning section 123 can be manufactured. When used in conjunction with the system 100, the fabricated bellows 120 may have sufficient flexibility to elastically deform when torsional force is applied by the rotation of the actuator 112, and may have sufficient strength to withstand the pressure difference between the vacuum chamber 101 and the actuator section 111.

[0045] Referring back to FIG. 1, the system 100 can further include a first flange 130. The first flange 130 can be fixed to the base 115 and the first end 121 of the bellows 120. The first flange 130 can be fixed to the base 115 by fasteners and / or welding. For example, as shown in FIGS. 4A and 4B, the first flange 130 may have a plurality of first mounting holes 131 configured to receive a first fastener 132 for fixing the first flange 130 to the base 115. The first flange 130 may also have a first seal gland 133 configured to receive a first seal ring 134. The first seal ring 134 may be made of metal. The first seal ring 134 can provide a seal between the first flange 130 and the base 115.

[0046] The first flange 130 can be fixed to the first end 121 of the bellows 120 by circumferential welding. For example, at least a portion of the first end 121 of the bellows 120 may be received within the inner diameter of the first flange 130 such that the outer surface of the first end 121 of the bellows 120 is welded to the inner surface of the first flange 130.

[0047] Referring back to FIG. 1, the system 100 can further include a second flange 140. The second flange 140 may be fixed to the component mount 110 and the second end 122 of the bellows 120. The second flange 140 can be fixed to the component mount 110 by fasteners and / or welding. For example, as shown in FIGS. 4A and 4B, the second flange 140 can have a plurality of second mounting holes 141 configured to receive a second fastener 142 for fixing the second flange 140 to the component mount 110. The second flange 140 may also have a second seal gland 143 configured to receive a second seal ring 144. The second seal ring 144 may be formed of metal. The second seal ring 144 can provide a seal between the second flange 140 and the component mount 110.

[0048] The second flange 140 can be fixed to the second end section 122 of the bellows 120 by circumferential welding. For example, at least a portion of the second end 122 of the bellows 120 may be received within the inner diameter of the second flange 140 such that the outer surface of the second end 122 of the bellows 120 is welded to the inner surface of the second flange 140.

[0049] The first flange 130 and the second flange 140 may be formed of metal. For example, the first flange 130 and the second flange 140 may be formed of 316 stainless steel. In this way, the assembly of the bellows 120, the first flange 130, and the second flange 140 can result in an all-metal rotary seal assembly.

[0050] The first flange 130 and the second flange 140 may be configured for various seals. The geometry of the first seal land 133 and the second seal land 143 may depend on the type of seal used. The first seal ring 134 and the second seal ring 144 may be a flexible metal seal, a conflat seal, a wire seal, an indium seal, etc. The flexible metal seal may comprise a tightly wound helical spring surrounded by one or more metal jackets. During compression, the spring can yield the jacket and ensure reliable contact with the sealing surface. The conflat seal is compressed by the knife edges of the first seal land 133 and the second seal land 143 to form a seal.

[0051] In system 100, the bellows 120 may provide a hermetic seal between the base 115 and the component mount 110 such that components 105 within the vacuum chamber 101 can be separated from particles and VOCs generated by the actuator 112 within the actuator section 111. Also, the bellows 120 can withstand torsional elastic deformation and allow rotation of the component mount 110 relative to the base 115 for in-place alignment of the components 105. In this way, system 100 can provide a cleaner inspection environment and improve system accuracy.

[0052] FIG. 5A is a flowchart of a method 200 according to an embodiment of the present disclosure. The method 200 can be used in a system such as the system 100. The method 200 may include the following steps.

[0053] In step 210, a component mount is provided within a vacuum chamber. The vacuum chamber may be pumped down to a low or vacuum pressure, such as UHV, by a vacuum pump. The component mount can hold components. The components may be optical members or other components that can be remotely actuated in a vacuum.

[0054] In step 220, an actuator is provided that is disposed between the component mount and the base. A bellows is disposed between the base and the component mount, and the bellows, base, and component mount define an actuator compartment therebetween. The bellows can provide a seal between the base and the component mount. The actuator compartment may be pumped down to a low or vacuum pressure by a vacuum pump.

[0055] In step 230, the component mount is rotated relative to the base using an actuator. The rotation of the component mount relative to the base causes torsional elastic deformation of the bellows. By using the actuator to twist the bellows, the component mount (and the components disposed thereon) can be rotated for alignment and the measurement accuracy can be improved. For example, the component mount may be rotated by 10 microradians or more relative to the base. The rotation range of the bellows within the elastic deformation range and the force required to cause torsional elastic deformation may depend on the material, thickness, and geometry of the bellows as well as the vacuum pressure within the vacuum chamber and the actuator compartment. For example, the rotation range of the bellows may be 1 to 10 microradians, 1 to 3 microradians, 1.3 to 3 microradians, 1.3 to 2 microradians, 2 to 3 microradians, or other ranges. Since the deformation of the bellows is within the elastic range, the bellows can recover to its original shape by rotation in the opposite direction and the rotation can be repeated. If the deformation of the bellows is within the inelastic range, the bellows may not be able to recover to its original shape, and such plastic deformation may break the seal of the actuator compartment and may require replacement of the bellows.

[0056] In method 200, the bellows may provide a sealed seal between the base and the component mount such that components within the vacuum chamber can be separated from particles and VOCs generated by the actuator within the actuator compartment, and the bellows may be capable of withstanding torsional elastic deformation to allow rotation of the component mount relative to the base for in-situ alignment of the components. In this way, method 200 can improve measurement accuracy.

[0057] According to an embodiment of the present disclosure, method 200 may further include the following steps for manufacturing the bellows shown in FIG. 5B.

[0058] In step 201, a bellows structure is electroformed on a mandrel. An exemplary electroforming process is shown in FIG. 3A, where a solid metal source and a conductive mandrel are placed in an electrolyte containing a salt of the metal to be electroformed, and a direct current is applied to the metal source (anode) and the mandrel (cathode). The direct current causes the deposition of metal on the outer surface of the mandrel until a bellows structure having the required thickness is achieved. The outer surface of the mandrel has vertical ribs corresponding to the vertical ribs of the bellows, and as a result, when the metal is deposited on the outer surface of the mandrel, the resulting bellows structure has the same vertical ribs.

[0059] In step 202, the mandrel is removed from the bellows structure to obtain the bellows. The mandrel can be separated intact, removed by melting, or chemically dissolved / etched to obtain the bellows.

[0060] In step 203, the bellows is placed between a base and a component mount within a vacuum chamber. For example, the bellows may be fixed to the base and the component mount via fasteners or welds.

[0061] Steps 201-203 may be performed before step 210, before step 220, and / or before step 230 of method 200.

[0062] The electroforming process of steps 201-203 can produce a monolithic thin bellows having a vertical rotating structure. When used in conjunction with method 200, the produced bellows may have sufficient flexibility to elastically deform when torsional forces are applied by the rotation of the actuator, and may have sufficient strength to withstand the pressure difference between the vacuum chamber and the actuator compartment.

[0063] Although disclosed as reducing particles and contamination on an optical component, the embodiments disclosed herein can also protect the actuator from the environment outside the actuator compartment. When cleaning an area with an optical component, a solvent, plasma, O3 , ultraviolet light, and / or H 2 can be used. These cleaning techniques may damage the actuator. The bellows can protect the actuator from these cleaning techniques.

[0064] The description provided throughout this disclosure focuses on particle control around optical components in EUV lithography tools, EUV metrology tools, or EUV reticle inspection tools. However, the embodiments disclosed herein should be construed as applicable to EUV optical tools or any critical area of an optical tool for other light wavelengths that are sensitive to the presence of particles. The embodiments disclosed herein can also be applied to other vacuum systems that are sensitive to particles, such as an electron beam system. For example, the embodiments disclosed herein can generally be used to align aspherical optical components by rotation around the beam axis.

[0065] Although the present disclosure has been described with respect to one or more particular embodiments, it will be understood that other embodiments of the present disclosure may be made without departing from the scope of the present disclosure. Accordingly, the present disclosure is considered to be limited only by the appended claims and their proper interpretation.

Claims

1. A system comprising: a vacuum chamber; a component mount disposed within the vacuum chamber; a base; a bellows disposed between the base and the component mount, the bellows, the base, and the component mount defining an actuator compartment therebetween and providing a seal between the base and the component mount; an actuator disposed within the actuator compartment and configured to rotate the component mount relative to the base; wherein rotation of the component mount relative to the base causes torsional elastic deformation of the bellows.

2. a first flange fixed to a first end of the base and the bellows; a second flange fixed to a second end of the component mount and the bellows; The system according to claim 1, further comprising.

3. The first flange is fixed to the first end of the bellows by circumferential welding; The system according to claim 2, wherein the second flange is fixed to the second end of the bellows by circumferential welding.

4. The system according to claim 2, wherein at least one of the first flange and the second flange comprises a seal gland, and a seal ring is disposed within the seal gland.

5. The system according to claim 1, wherein the bellows comprises a circumferential section disposed between a first end and a second end, the circumferential section comprising vertical ribs extending from the first end to the second end.

6. The system according to claim 5, wherein the perimeter of the circumferential section has a sinusoidal shape defined by the vertical ribs.

7. The system according to claim 1, wherein the bellows is made of a nickel cobalt alloy.

8. The system according to claim 1, wherein the bellows is manufactured by electroforming.

9. The system according to claim 1, wherein the bellows has a substantially circular cross-section.

10. an optical component disposed on the component mount within the vacuum chamber; The system according to claim 1, further comprising, wherein rotation of the component mount relative to the base causes corresponding rotation of the optical component.

11. A method comprising: providing a component mount within a vacuum chamber; Provide an actuator disposed between the component mount and the base, the bellows is disposed between the base and the component mount, and the bellows, the base, and the component mount define an actuator compartment therebetween, and the bellows provides a seal between the base and the component mount; Rotate the component mount relative to the base using the actuator, causing torsional elastic deformation of the bellows by the rotation of the component mount relative to the base; A method comprising the steps of. [

12. ] The first flange is fixed to the first end of the base and the bellows, The second flange is fixed to the second end of the component mount and the bellows, the method according to claim 11. [

13. ] The first flange is fixed to the first end of the bellows by circumferential welding, The second flange is fixed to the second end of the bellows by circumferential welding, the method according to claim 12. [

14. ] At least one of the first flange and the second flange comprises a seal gland, and a seal ring is disposed within the seal gland, the method according to claim 12. [

15. ] The bellows comprises a swivel section disposed between a first end and a second end, the swivel section comprising a vertical rib extending from the first end to the second end, the method according to claim 11. [

16. ] The periphery of the swivel section has a sinusoidal shape defined by the vertical rib, the method according to claim 15. [

17. ] The bellows is made of a nickel cobalt alloy, the method according to claim 11. [

18. ] Electroforming a bellows structure on a mandrel; Removing the mandrel from the bellows structure to obtain the bellows; Placing the bellows between the base and the component mount within the vacuum chamber; The method according to claim 11, further comprising the steps of. [

19. ] The bellows has a substantially circular cross-section, the method according to claim 11. [

20. ] The optical component is disposed on the component mount within the vacuum chamber, and the rotation of the component mount relative to the base causes a corresponding rotation of the optical component, the method according to claim 11.

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