Method for manufacturing a damping device, lithography equipment, projection system and device manufacturing method

Abstract

The present invention relates to a method for manufacturing a damping device comprising a first part and a second part, the method comprising the following steps: a) providing a damping material in a space between the first part and the second part so that the damping material is in a compressed state in the space; and b) heating the damping device to a predetermined temperature so as to adhere the damping material to the first part and the second part.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to European application 17207548.3 filed on December 15, 2017, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The invention relates to a method for producing a damping device, the use of such a damping device in a lithographic apparatus or a projection system, and the use of such a lithographic apparatus in a device manufacturing method. Background Art

[0004] A lithographic apparatus is a machine that applies a desired pattern to a substrate (usually applying the desired pattern to a target portion of the substrate). A lithographic apparatus can be used, for example, when manufacturing an integrated circuit (IC). In this case, a pattern forming device (also referred to as a "mask" or "reticle") can be used to generate a circuit pattern to be formed on a single layer of the IC. This pattern can be transferred to a target portion (e.g., including one or several dies, or a portion of a die) on a substrate (e.g., a silicon wafer). The transfer of the pattern is usually performed by imaging onto a layer of radiation-sensitive material (resist) disposed on the substrate. Typically, a single substrate will contain a network of adjacent target portions that are patterned continuously. Conventional lithographic apparatus includes a so-called stepper, in which each target portion is irradiated by exposing the entire pattern on the target portion at one time; and a so-called scanner, in which each target portion is irradiated by scanning the pattern in a given direction (the "scanning" direction) with a radiation beam while simultaneously scanning the substrate in a direction parallel or antiparallel to that direction. Additionally, the pattern may be transferred from the patterning device to the substrate by imprinting the pattern onto the substrate.

[0005] In a lithographic apparatus, a damping device is used to support and isolate an element, such as an optical element, relative to a frame. Currently, providing a damping device, especially a passive damping device, with damping material requires a complex manufacturing process to ensure reliable force transmission between the damping device part and the damping material. Summary of the invention

[0006] It is desirable to provide an improved damping device, in particular a damper manufacturing process which is relatively easy and ensures reliable force transmission between device parts and damping material.

[0007] According to an embodiment of the present invention, there is provided a method for manufacturing a damping device, the damping device comprising a first part and a second part, the method comprising the following steps:

[0008] a) providing a damping material in a space between the first portion and the second portion such that the damping material is in compression in the space; and

[0009] b) heating the damping device to a predetermined temperature so as to adhere the damping material to the first portion and the second portion.

[0010] According to another embodiment of the present invention, a projection system is provided, which is configured to project a patterned radiation beam onto a target portion of a substrate, wherein the projection system includes an optical element supported by one or a damping device, which is manufactured using a method according to the present invention.

[0011] According to another embodiment of the present invention, there is provided a lithographic apparatus comprising one or more damping devices manufactured using a method according to the present invention.

[0012] According to a further embodiment of the present invention, there is provided a device manufacturing method, in which the lithographic apparatus according to the present invention is used. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which corresponding reference numerals indicate corresponding parts, and in which:

[0014] - Figure 1 depicts a lithographic apparatus according to an embodiment of the invention;

[0015] - Figure 2 schematically depicts a projection system according to an embodiment of the present invention;

[0016] - Figure 3 schematically depicts a cross-sectional view of a damping device according to an embodiment of the present invention;

[0017] - Figure 4 schematically depicts a cross-sectional view of a damping device according to another embodiment of the present invention;

[0018] - Figure 5 schematically depicts a cross-sectional view of a spring damper device according to another embodiment of the present invention; and

[0019] - Figure 6 A block diagram of a preparation method according to an embodiment of the present invention is schematically depicted. DETAILED DESCRIPTION

[0020] Figure 1 A lithographic apparatus according to an embodiment of the present invention is schematically depicted. The apparatus comprises:

[0021] - an illumination system (IL) configured to condition a radiation beam B (e.g. UV radiation or EUV radiation);

[0022] a support structure (e.g. mask table) MT constructed to support a patterning device (e.g. mask) MA and connected to a first positioner PM configured to accurately position the patterning device according to certain parameters;

[0023] a substrate table (e.g. wafer stage) WTa or WTb constructed to hold a substrate (e.g. a resist coated wafer) W and connected to a second positioner PW configured to accurately position the patterning device according to certain parameters; and

[0024] - a projection system (eg a refractive projection lens system) PS configured to project the pattern imparted to the radiation beam B by the patterning device MA onto a target portion C of the substrate W (eg comprising one or more dies).

[0025] The illumination system may include various types of optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic or other types of optical components, or any combination thereof, for directing, shaping and / or controlling radiation.

[0026] The support structure MT supports the pattern forming device MA (i.e., bears the weight of the pattern forming device MA). The support structure MT holds the pattern forming device MA in a manner that depends on the orientation of the pattern forming device MA, the design of the lithographic equipment, and other conditions (e.g., whether the pattern forming device MA is maintained in a vacuum environment). The support structure MT may use mechanical, vacuum, electrostatic, or other clamping techniques to hold the pattern forming device MA. The support structure MT may be, for example, a frame or a table, which may be fixed or movable as required. The support structure MT may ensure that the pattern forming device MA is in a desired position, for example, relative to the projection system PS. Any use of the term "reticle" or "mask" herein may be considered synonymous with the more general term "pattern forming device."

[0027] The term "patterning device" as used herein should be broadly interpreted as referring to any device that can be used to impart a radiation beam with a pattern in its cross-section so as to produce a pattern in a target portion of the substrate W. It should be noted that the pattern imparted to the radiation beam may not exactly correspond to the desired pattern in the target portion of the substrate W, for example where the pattern includes phase-shifting features or so called assist features. Typically, the pattern imparted to the radiation beam will correspond to a specific functional layer in a device being produced in the target portion, such as an integrated circuit.

[0028] The patterning device MA may be transmissive or reflective. Examples of patterning devices include masks, programmable mirror arrays, and programmable LCD panels. Masks are well known in lithography and include binary, alternating phase-shift, attenuated phase-shift masks, and various hybrid mask types. An example of a programmable mirror array is a matrix arrangement of small mirrors, each of which can be independently tilted to reflect an incoming radiation beam in different directions. The tilted mirrors impart a pattern to the radiation beam reflected by the mirror matrix.

[0029] As used herein, the terms "radiation" and "beam" include all types of electromagnetic radiation, including ultraviolet (UV) radiation (e.g., having a wavelength equal to or approximately 365 nm, 248 nm, 193 nm, 157 nm or 126 nm) and extreme ultraviolet (EUV) radiation (e.g., having a wavelength in the range of 5-20 nm), as well as particle beams such as ion beams or electron beams.

[0030] The term "projection system" as used herein should be broadly interpreted as including any type of projection system, including refractive, reflective, catadioptric, magnetic, electromagnetic, and electrostatic optical systems, or any combination thereof, as appropriate for the exposure radiation used or other factors such as the use of immersion liquid or the use of a vacuum. Any use of the term "projection lens" as used herein may be considered synonymous with the more general term "projection system".

[0031] As depicted here, the device is transmissive (eg, employing a transmissive mask). Alternatively, the device may be reflective (eg, employing a programmable mirror array of the type described above, or employing a reflective mask).

[0032] The lithographic apparatus may be of a type having two (dual stage) or more substrate tables (and / or two or more mask tables). In such a "multi-stage" machine, the extra tables may be used in parallel, or preparatory steps may be carried out on one or more tables while one or more other tables are being used for exposure. Figure 1 The two substrate tables WTa and WTb in the example of FIG are illustrative of this situation. Although the invention disclosed herein may be used in a stand-alone manner, in particular it may provide additional functionality in a pre-exposure measurement stage of a single stage apparatus or a multi-stage apparatus.

[0033] The lithographic apparatus may also be of a type in which at least a portion of the substrate may be covered by a liquid having a relatively high refractive index, such as water, so as to fill the space between the projection system PS and the substrate W. Immersion liquid may also be applied to other spaces in the lithographic apparatus, such as the space between the pattern forming device MA and the projection system PS. It is well known in the art that immersion techniques are used to increase the numerical aperture of the projection system. The term "immersion" as used herein does not mean that structures such as the substrate W must be immersed in the liquid, but only means that the liquid is located between the projection system PS and the substrate W during exposure.

[0034] Reference Figure 1 , the illuminator IL receives a radiation beam from a radiation source SO. The radiation source SO and the lithographic apparatus may be separate entities, for example when the radiation source SO is an excimer laser. In this case, the radiation source SO is not considered to constitute a part of the lithographic apparatus, and the radiation beam is transferred from the radiation source SO to the illuminator IL with the aid of a beam delivery system BD comprising, for example, suitable directional mirrors and / or a beam expander. In other cases, the radiation source may be an integral part of the lithographic apparatus, for example when the radiation source is a mercury lamp. The radiation source SO and the illuminator IL, and the beam delivery system BD provided if necessary, may be referred to together as a radiation system.

[0035] The illuminator IL may include an adjuster AD for adjusting the angular intensity distribution of the radiation beam. Typically, at least the outer and / or inner radial extent (commonly referred to as σ-outer and σ-inner, respectively) of the intensity distribution in a pupil plane of the illuminator may be adjusted. Furthermore, the illuminator IL may include various other components, such as an integrator IN and a condenser CO. The illuminator IL may be used to adjust the radiation beam so as to have a desired uniformity and intensity distribution in its cross-section.

[0036] The radiation beam B is incident on a patterning device MA (e.g. a mask) held on a support structure MT (e.g. a mask table) and is patterned by the patterning device MA. After passing through the patterning device MA, the radiation beam B passes through a projection system PS which focuses the beam onto a target portion C of the substrate W. With the aid of a second positioner PW and a position sensor IF (e.g. an interferometer arrangement, a linear encoder or a capacitive sensor), the substrate table WTa / WTb can be precisely moved, for example in order to position different target portions C in the path of the radiation beam B. Similarly, the first positioner PM and a further position sensor (in the embodiment of the present invention) can be used, for example, after mechanical acquisition from a mask library or during scanning. Figure 1The pattern forming device MA is accurately positioned relative to the path of the radiation beam B using a plurality of actuators (not explicitly depicted in the figure). In general, movement of the support structure MT may be achieved with the aid of a long-stroke module (coarse positioning) and a short-stroke module (fine positioning) which form part of the first positioner PM. Similarly, movement of the substrate table WTa / WTb may be achieved using a long-stroke module and a short-stroke module which form part of the second positioner PW. In the case of a stepper (as opposed to a scanner), the support structure MT may be connected only to the short-stroke actuator, or may be fixed. The pattern forming device MA and the substrate W may be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2. Although the substrate alignment marks shown in the figures occupy dedicated target portions, they may be located in the spaces between multiple target portions (these are commonly known as scribe alignment marks). Similarly, in the case where more than one die is arranged on the mask MA, the mask alignment marks M1, M2 may be located between multiple dies.

[0037] The depicted apparatus can be used in at least a scanning mode. In scanning mode, the support structure MT and substrate table WTa / WTb are scanned synchronously while projecting a pattern imparted to the radiation beam onto a target portion C (i.e. a single dynamic exposure). The speed and direction of the substrate table WTa / WTb relative to the support structure MT may be determined by the (or less) magnification and image reversal characteristics of the projection system PS. In scanning mode, the maximum size of the exposure field limits the width of the target portion in a single dynamic exposure (in the non-scanning direction), while the length of the scanning movement determines the height of the target portion (in the scanning direction).

[0038] In addition to the scanning mode, the depicted device may be used in at least one of the following modes:

[0039] 1. In step mode, the support structure MT and substrate table WTa / WTb are held substantially stationary (i.e. a single static exposure) while an entire pattern imparted to the radiation beam is projected at one time onto a target portion C. The substrate table WTa / WTb is then shifted in the X and / or Y direction so that a different target portion C can be exposed. In step mode, the maximum size of the exposure field limits the size of the target portion C imaged in a single static exposure.

[0040] 2. In another mode, the support structure MT is held substantially stationary, thereby holding the programmable patterning device, and the substrate table WTa / WTb is moved or scanned, while a pattern imparted to the radiation beam is projected onto a target portion C. In this mode, a pulsed radiation source is typically employed, and the programmable patterning device is updated as required after each movement of the substrate table WTa / WTb, or between successive radiation pulses during a scan. This mode of operation can be readily applied to maskless lithography utilizing a programmable patterning device, such as a programmable mirror array of the type mentioned above.

[0041] Combinations and / or variations on the above-described modes of use, or entirely different modes of use, may also be employed.

[0042] The lithographic apparatus LA is of a so-called dual-stage type having two substrate tables WTa and WTb and two stations, an exposure station and a measuring station, between which the substrate table can be exchanged. While one substrate on one substrate table is being exposed at the exposure station, another substrate can be loaded onto the other substrate table at the measuring station so that various preparatory steps can be performed. The preparatory steps may comprise mapping the surface of the substrate using a level sensor LS and measuring the positions of alignment marks on the substrate using an alignment sensor AS. This enables a substantial increase in the throughput of the apparatus. If the position sensor IF is not able to measure the position of the substrate table when the substrate table is at the measuring station and at the exposure station, a second position sensor may be provided so that the position of the substrate table can be tracked at both stations.

[0043] The device also includes a lithographic equipment control unit LACU, which controls all movements and measurements of the various actuators and sensors described. The control unit LACU also includes signal processing and data processing capabilities to implement the desired calculations related to the operation of the device. In practice, the control unit LACU will be implemented as a system with many subunits, each of which handles the real-time data acquisition, processing and control of the subsystems or components in the device. For example, a processing subsystem can be dedicated to the servo control of the substrate positioner PW. Discrete units can even handle coarse actuators and fine actuators or different axes. Another unit can be dedicated to the readout of the position sensor IF. The overall control of the device can be controlled by a central processing unit, which communicates with these subsystem processing units, with operators and with other equipment involved in the lithographic manufacturing process.

[0044] Figure 2 Schematically depicts Figure 1 The projection system PS of the lithographic apparatus of FIG. The projection system PS is a projection system according to an embodiment of the present invention as will be described below. Figure 2, two views of the projection system PS are shown, namely view (a) and view (b). View (a) is a bottom view, and view (b) is a side view. Both views have similar Figure 1 A coordinate system indicating the X, Y, and Z directions.

[0045] Using three damping devices according to an embodiment of the invention from the frame RF (see Figure 1 ) supports the projection system PS, the frame RF being for example a base frame, a measurement frame or any other frame. The skilled person will appreciate that any number of spring damper devices 1 can be envisaged and the three damper devices 1 shown in the figure are only examples.

[0046] from Figure 2 It can be clearly seen that the three damping devices 1 are evenly distributed along the circumference of the projection system PS. When each damping device 1 is capable of supporting the projection system PS with at least two degrees of freedom, such a distribution allows supporting the projection system PS with six degrees of freedom.

[0047] Figure 3 A cross-sectional view of a damping device 1 according to an embodiment of the present invention is depicted. The damping device 1 comprises a first portion 3a and a second portion 3b. In this embodiment, the first portion 3a may be a portion connecting the damping device 1 to the Figure 1 and Figure 2 In this embodiment, the second portion 3b may be a portion for connecting the damping device 1 to the frame (eg Figure 1 The connecting part of the frame RF) shown.

[0048] The left blade LB is connected to the first part 3a and the right blade RB is connected to the second part 3b. During assembly of the damping device 1, the left blade LB and the right blade RB will be positioned relative to each other so that the left blade LB and the right blade RB delimit a space S at their opposite sides. The space S is filled with a damping material D. First, the damping material D is in an uncompressed state when introduced into the space S. Then, the damping material D can be brought into a compressed state by moving the first part 3a and the second part 3b and thus moving the left blade LB and the right blade RB towards each other, thereby reducing the volume of the space S between the left blade LB and the right blade RB to such an extent that the damping material D is brought into a compressed state.

[0049] In an embodiment, the damping material D is a viscoelastic material, preferably a thermoplastic elastomer.

[0050] When the movement between the first part 3a and the second part 3b causes the damping material D to deform, the damping function of the damping material D is realized, wherein the damping material D at least partially dissipates the corresponding energy as heat. In an embodiment, the damping device 1 is arranged parallel to the spring device so as to cooperate with the spring device.

[0051] Figure 4 A cross-sectional view of a damping device 1 according to another embodiment of the present invention is depicted. The damping device 1 comprises a first portion 3a and a second portion 3b. In this embodiment, the first portion 3a may be a portion connecting the damping device 1 to the Figure 1 and Figure 2 In this embodiment, the second portion 3b may be a portion for connecting the damping device 1 to the frame (eg Figure 1 The connecting part of the frame RF) shown.

[0052] The center blade CB is connected to the first part 3a, and the left blade LB and the right blade RB are connected to the second part 3b. The left blade LB and the center blade CB define a first space S1 on their opposite sides. The center blade CB and the right blade RB define a second space S2 on their opposite sides. The spaces S1 and S2 are filled with damping materials D1 and D2, respectively. First, the damping materials D1 and D2 may be in an uncompressed state when they are introduced into the spaces S1 and S2, respectively. Then, the damping materials D1 and D2 can be changed into a compressed state by moving the left blade LB and the right blade RB toward the center blade, for example, by clamping the left blade LB and the right blade RB to the second part 3b, thereby reducing the volume of the spaces S1 and S2 to the extent that the damping materials D1 and D2 are changed into a compressed state.

[0053] In an embodiment, the damping material D1 , D2 is a viscoelastic material, preferably a thermoplastic elastomer.

[0054] When the movement between the first part 3a and the second part 3b causes the damping material D1, D2 to deform, the damping function of the damping material D1, D2 is achieved, wherein the damping material D1, D2 dissipates the corresponding energy at least partially as heat. In an embodiment, the damping device 1 is arranged parallel to the spring device so as to cooperate with the spring device.

[0055] Figure 5 A cross-sectional view of a damping device 1 according to another embodiment of the present invention is depicted. In this embodiment, the damping device 1 is a spring damping device 1, which comprises: a spring 3, the spring 3 having a connecting portion 3a for connecting the spring damping device 1 to the projection system PS; a connecting portion 3b for connecting the spring damping device 1 to a frame (e.g. Figure 1The invention relates to a frame RF as shown in FIG. 1 ; and a connecting portion 3c, which connects the connecting portion 3a to the connecting portion 3b, wherein the spring portion 3c is elastic and can store mechanical energy when deformed. Therefore, the spring portion 3c pushes the connecting portion 3a and the connecting portion 3b to a balanced position relative to each other.

[0056] The spring 3 further includes a left first blade L1B, a right first blade R1B, a left second blade L2B and a right second blade R2B, a left third blade L3B, a right third blade R3B, a left fourth blade L4B and a right fourth blade R4B.

[0057] The first left blade L1B and the first right blade R1B as well as the second left blade L2B and the second right blade R2B are connected to the connecting part 3a via one or more bolts 5, which cooperate with one or more corresponding threaded holes H2 in the second left blade L2B, thereby allowing the blades and the connecting part 3a to be clamped together to form the first part of the spring 3.

[0058] The third blade L3B on the left and the third blade R3B on the right as well as the fourth blade L4B on the left and the fourth blade R4B on the right are connected to the connecting part 3b via one or more bolts 6, which cooperate with one or more corresponding threaded holes H4 in the fourth blade L4B on the left, thereby allowing the blade and the connecting part 3b to be clamped together to form the second part of the spring 3.

[0059] The arrangement of the blades and springs allows Figure 5 In the section of , when moving from left to right, the following elements and spaces are encountered in the following order:

[0060] 1) The fourth blade on the left side L4B;

[0061] 2) a first space S1, which is defined on one side by the left fourth blade L4B and on the opposite side by the left second blade L2B;

[0062] 3) the second left leaf L2B;

[0063] 4) a second space S2, which is bounded on one side by the left second blade L2B and on the opposite side by the left third blade L3B;

[0064] 5) the third blade on the left side L3B;

[0065] 6) a third space S3, which is defined on one side by the left third blade L3B and on the opposite side by the left first blade L1B;

[0066] 7) The first left blade L1B;

[0067] 8) a fourth space S4, which is defined on one side by the left first blade L1B and on the opposite side by the connecting portion 3b;

[0068] 9) connecting portion 3b;

[0069] 10) a fifth space S5, which is defined on one side by the connecting portion 3b and on the opposite side by the right first blade R1B;

[0070] 11) The first blade on the right side R1B;

[0071] 12) a sixth space S6, the sixth space S6 being defined on one side by the right first blade R1B and on the opposite side by the right third blade R3B;

[0072] 13) the third blade on the right side R3B;

[0073] 14) a seventh space S7, one side of which is bounded by the right third blade R3B and the opposite side is bounded by the right second blade R2B;

[0074] 15) the second blade on the right side R2B;

[0075] 16) an eighth space S8, the eighth space S8 being defined on one side by the right second blade R2B and on the opposite side by the right fourth blade R4B; and

[0076] 17) The fourth blade on the right side R4B.

[0077] The spaces S1 to S8 are filled with corresponding damping materials D1 to D8, respectively. First, the damping materials D1 to D8 may be in an uncompressed state when introduced into the spaces S1 to S8. The volume of the damping materials D1 to D8 is selected so that when the blades are clamped to the corresponding connection parts by the corresponding bolts 5 and 6, the volume of the spaces S1 to S8 is reduced to such an extent that the damping materials D1 to D8 become compressed.

[0078] In an embodiment, the damping materials D1 to D8 are viscoelastic materials, preferably thermoplastic elastomers.

[0079] The advantage of the blade being detachably mounted to the connecting portion of the spring is that it is relatively easy to introduce the damping materials D1 to D8 into the corresponding spaces S1 to S8, but in addition, after the damping materials D1 to D8 are introduced into the corresponding spaces S1 to S8, any misalignment of the damping material can be more easily corrected by removing the blade and making another attempt.

[0080] Although the described embodiment utilizes the reduction in volume of the spaces S1 to S8 during assembly to place the damping materials D1 to D8 in a compressed state, the volume of the damping materials D1 to D8 may initially match the volume of the spaces S1 to S8, but then the damping materials D1 to D8 may be changed to a compressed state by expansion of the damping materials D1 to D8. This may be achieved, for example, by lowering the temperature of the damping materials D1 to D8 so that the volume of the damping materials D1 to D8 matches or is smaller than the volume of the spaces S1 to S8, and after introducing the damping materials D1 to D8 into the spaces, returning the damping materials to room temperature, thereby causing the damping materials D1 to D8 to expand, resulting in the damping materials D1 to D8 being changed to a compressed state.

[0081] Another possibility is to introduce the damping material D1 to D8 into the respective spaces S1 to S8 in a compressed state, for example when the blade is first clamped onto the corresponding connecting part and then the damping material D1 to D8 is introduced into the spaces S1 to S8.

[0082] When the relative movement between the connecting parts 3a, 3b causes the damping materials D1 to D8 to deform, the damping function of the damping materials D1 to D8 is realized, wherein the damping materials D1 to D8 at least partially dissipate the corresponding energy as heat. Figure 5 This means that the blades need to be firmly connected to the corresponding connecting portions, and the damping materials D1 to D8 are also connected to the corresponding blades or other portions of the spring that define the space in which the damping materials are located.

[0083] Figure 6 A block diagram of a method for manufacturing a damping device, for example according to Figures 3 to 5 The damping device 1 of the embodiment is used, for example, by supporting Figure 1 and Figure 2 The projection system shown is used in Figure 1 The method comprises a first step A. In the first step A, a damping material is provided in a space between the first part and the second part, such that the damping material is in a compressed state in the space.

[0084] Then, in step B, the damping device is heated to a predetermined temperature so as to adhere the damping material to the first part and the second part. For example, the adhesion can be achieved by reducing the Young's modulus of the damping material to better adapt to the surfaces of the first part and the second part (i.e., increasing the contact surface between the damping material and the first part and the second part).

[0085] Although the predetermined temperature is preferably below the melting temperature of the damping material, it is high enough to allow the damping material to adjust itself to the surfaces of the first and second parts of the spring.Preferably, the device is maintained at the predetermined temperature for a predetermined period of time.

[0086] In step C, after being heated to a predetermined temperature, the damping device is allowed to cool to obtain a temperature equal to room temperature. Although cooling can be passive by simply removing the heat source, cooling can also be active, for example by subjecting the device to an air flow having room temperature or lower.

[0087] The method preferably comprises that after step C, the damping material between the first part and the second part of the spring is still in a compressed state. Figure 4 and Figure 5 This is easy to implement for the embodiment of Figure 3 For the embodiment of the present invention, additional elements (such as spring elements) may be needed to push the first part 3a and the second part 3b towards each other.

[0088] Although the described embodiments refer to heating the damping device to a predetermined temperature, it is expressly noted here that in some embodiments, depending on the damping material used, the heating step of the damping device can be omitted, or the predetermined temperature can be brought close to the ambient temperature. In an embodiment, the predetermined temperature is 20 degrees or higher, preferably 25 degrees or higher, more preferably 35 degrees or higher, and most preferably 45 degrees or higher. In an embodiment, the predetermined temperature is 100 degrees or lower, preferably 80 degrees or lower, more preferably 60 degrees or lower, and most preferably 55 degrees or lower. The temperatures mentioned are in degrees Celsius. Heating the damping device can have the advantage of accelerating the process of adhering the damping material to the first part and the second part in a compressed state. Therefore, the heating step is only omitted when there is enough time to carry out the process.

[0089] Although specific reference may be made herein to the use of lithographic apparatus in IC manufacturing, it should be understood that the lithographic apparatus described herein may have other applications, such as manufacturing integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads, etc. It will be understood by those skilled in the art that in these alternative applications, any term "wafer" or "die" used herein may be considered synonymous with the more general term "substrate" or "target portion", respectively. The substrate referenced herein may be processed before or after exposure, such as in a track or coating development system (a tool that typically applies a resist layer to a substrate and develops the exposed resist), a metrology tool, and / or an inspection tool. Where applicable, the content disclosed herein may be applied to such and other substrate processing tools. In addition, a substrate may be processed more than once, such as to produce a multi-layer IC, so that the term "substrate" used herein may also refer to a substrate that already contains multiple processed layers.

[0090] Although the above may specifically refer to the use of embodiments of the invention in the context of optical lithography, it will be appreciated that the invention may be used in other applications such as imprint lithography and is not limited to optical lithography where the context permits. In imprint lithography, the topography in the patterning device defines the pattern produced on the substrate. The topography of the patterning device may be printed into a resist layer provided to the substrate, and the resist is then cured by applying electromagnetic radiation, heat, pressure, or a combination thereof. After the resist is cured, the patterning device is removed from the resist, leaving a pattern therein.

[0091] Although specific embodiments of the present invention have been described above, it should be understood that the present invention may be practiced in a manner different from that described. For example, the present invention may take the form of a computer program (the computer program contains one or more machine-readable instruction sequences describing the above method), or take the form of a data storage medium (such as a semiconductor memory, a magnetic disk or an optical disk) storing such a computer program.

[0092] The above description is intended to be illustrative rather than limiting. Accordingly, it will be appreciated by those skilled in the art that modifications may be made to the present invention without departing from the scope of the claims set forth below.

Claims

1. A method for manufacturing a damping device, the damping device comprising a first part and a second part, the method comprising the following steps: a) providing a damping material in a space between the first part and the second part of the spring acting as the damping means, such that the damping material is in a compressed state in the space; and b) heating the damping device to a predetermined temperature so as to adhere the damping material to the first portion and the second portion, Wherein the predetermined temperature is below the melting temperature of the damping material, but high enough to cause the damping material to adjust itself to the surface of both the first portion and the second portion of the spring.

2. The method according to claim 1, wherein: The damping device is a spring damping device comprising a spring configured to act between the first part and the second part.

3. The method according to claim 1 or 2, wherein: The damping material is a viscoelastic material, preferably a thermoplastic elastomer.

4. The method according to any one of claims 1 to 3, wherein: Step b) is performed such that the damping material between the first portion and the second portion is still in a compressed state after step b).

5. The method according to any one of claims 1 to 4, wherein: The first part and the second part provide a plurality of spaces, one side of the plurality of spaces being defined by the first part and the opposite side being defined by the second part, wherein each of the plurality of spaces is provided with a damping material such that the damping material is in a compressed state in the corresponding space.

6. The method according to any one of claims 1 to 5, wherein: The first portion has two degrees of freedom relative to the second portion, and the damping material is arranged to provide damping in both degrees of freedom.

7. The method according to any one of claims 1 to 6, wherein: In step b), the damping device is maintained at a predetermined temperature for a predetermined period of time.

8. The method according to any one of claims 1 to 7, wherein: In step a), the damping material is introduced into the space in an uncompressed state and subsequently brought into a compressed state by reducing the volume of the space.

9. The method according to any one of claims 1 to 7, wherein: In step a), the damping material is introduced into the space in an uncompressed state and subsequently brought into a compressed state by expansion of the damping material.

10. The method according to any one of claims 1 to 7, wherein: In step a), the damping material is introduced into the space in a compressed state.

11. The method according to any one of claims 1 to 10, wherein: The damping device further includes a first blade connected to the first portion, and a second blade connected to the second portion, and the space between the first portion and the second portion of the spring is defined between the first blade and the second blade, and at least one of the first blade and the second blade of the damping device defining the space is detachably mounted to the damping device.

12. A lithographic apparatus comprising a damping device manufactured using the method according to any one of claims 1-11.

13. The lithographic apparatus according to claim 12, further comprising: - an illumination system configured to condition the radiation beam; a support configured to support a patterning device capable of imparting a pattern to the radiation beam in its cross-section to form a patterned radiation beam; - a substrate table configured to hold a substrate; as well as - a projection system configured to project the patterned radiation beam onto a target portion of the substrate, Wherein, the projection system comprises an optical element, the optical element is supported by one or more damping devices, and the damping devices are manufactured using the method according to any one of claims 1-11.

14. A projection system configured to project a patterned radiation beam onto a target portion of a substrate, wherein: The projection system comprises an optical element supported by one or more damping devices, the damping devices being manufactured using a method according to any one of claims 1-11.

15. A device manufacturing method, wherein: Use of a lithographic apparatus according to claim 12 or 13.

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