Laser beam aperture

Abstract

A light source for a photolithography system includes an optical component and an aperture. The optical component includes a first side having a first surface and a second surface. The aperture is positioned on the first surface of the first side of the prism, or positioned adjacent to and parallel to the surface. The aperture includes a first portion and a second portion. The first portion of the aperture blocks light from entering the optical component and is capable of reflecting a portion of the incident beam toward a beam collector. The second portion of the aperture allows a portion of the beam to enter and exit the first side of the optical component.

Description

Cross-references to related applications

[0001] This application claims priority to U.S. Patent Application No. 63 / 616,991, filed December 29, 2023, entitled “LASER BEAM APERTURE”, which is incorporated herein by reference in its entirety. Technical Field

[0002] This disclosure relates to laser light sources, such as deep ultraviolet (DUV) radiation, extreme ultraviolet (EUV) radiation, and X-ray radiation. Laser light sources can be used as exposure radiation, for example, in photolithography apparatuses and systems. Background Technology

[0003] A photolithography apparatus is a machine that applies a desired pattern to a substrate, typically a target portion of the substrate. For example, photolithography apparatuses can be used in the fabrication of integrated circuits (ICs). In this case, a patterning device (which may be a mask or stencil) can be used to generate a circuit pattern to be formed on an individual layer of the IC. This pattern can then be transferred to a target portion of a substrate (e.g., a portion comprising one or more dies). The transfer of the pattern is typically via imaging on a layer of radiation-sensitive material (photoresist, or simply "resist") disposed on the substrate. Generally, a single substrate will comprise a network of continuously patterned adjacent target portions. Known photolithography apparatuses include: so-called steppers, in which each target portion is irradiated by exposing the entire pattern to the target portion at once; and so-called scanners, in which each target portion is irradiated by scanning the pattern in a given direction ("scanning" direction) with a radiation beam, while simultaneously scanning the target portion parallel or antiparallel to this scanning direction. A pattern can also be transferred from a patterning apparatus to a substrate by imprinting the pattern onto the substrate.

[0004] Photolithography apparatuses typically include an illumination system that modulates the radiation generated by a radiation source before it is incident on the patterning apparatus. Patterned beams of deep ultraviolet (DUV) light can be used to create extremely small features on a substrate. DUV light generally refers to radiation with wavelengths ranging from 126 nm to 438 nm. Pulsed discharge sources, such as gas discharge lasers, can be used to generate deep ultraviolet (DUV) light.

[0005] Alternatively, patterned beams of extreme ultraviolet (EUV) light can be used to create extremely small features on a substrate. EUV light (sometimes also referred to as soft X-rays) is generally defined as electromagnetic radiation with wavelengths in the range of about 5–100 nm. One wavelength of particular interest for photolithography is 13.5 nm.

[0006] Methods for generating EUV light include, but are not necessarily limited to, converting a source material into a plasma state having chemical elements that emit radiation in the EUV range. These elements may include, but are not necessarily limited to, xenon, lithium, and tin.

[0007] The throughput of a photolithography apparatus can be affected by the power of the light generated by the radiation source in the irradiation system. As the radiation source generates higher power light, its optical components become more susceptible to damage. When the damage reaches a certain threshold, the system needs to be shut down and the optical components replaced. Summary of the Invention

[0008] Therefore, laser source elements capable of generating high-power light can be designed. For example, the aperture of the optical components of a beam reverser module, such as a laser source, can be designed and positioned based on what is described herein.

[0009] In some aspects, a system includes an optical component and an aperture. In some aspects, the optical component includes a first side. The first side includes a first surface and a second surface. In some aspects, the aperture is positioned on or adjacent to the first surface of the first side of the optical component and substantially parallel to the surface. In some aspects, the aperture may include a first portion and a second portion. In some aspects, the first portion of the aperture is configured to block light from entering a prism. In some aspects, the second portion of the aperture is configured to allow the first portion of the beam to enter and exit the first side of the prism. In some aspects, the first portion of the aperture faces the second portion of the beam reflected by a beam dump.

[0010] In some aspects, a photolithography system includes a light source. In some aspects, the light source includes a cavity, an optical component comprising a first surface, and an aperture on or adjacent to and parallel to the first surface of the optical component. In some aspects, the optical component is configured to reverse the direction of a beam exiting the cavity. In some aspects, the aperture is configured to block a portion of the beam from reaching the optical component. In some aspects, the aperture reduces damage to the optical component and the cavity by decreasing the beam fluence.

[0011] Further features of various aspects of this disclosure are described in detail below in conjunction with the accompanying drawings. It should be noted that this disclosure is not limited to the specific aspects described herein. Such aspects described herein are for illustrative purposes only. The remaining aspects will be apparent to those skilled in the art based on the teachings included herein. Attached Figure Description

[0012] The accompanying drawings (which have been incorporated herein and form part of the specification) illustrate this disclosure and, together with the description, further assist in explaining the principles of this disclosure and enabling those skilled in the art to make and use the aspects described herein.

[0013] Figure 1A and 1B The photolithography apparatus is shown according to some aspects.

[0014] Figure 1C The photolithography unit is shown according to some aspects.

[0015] Figure 2A and 2B Another lithography apparatus is shown according to some aspects.

[0016] Figure 3 The radiation sources are shown according to some aspects.

[0017] Figure 4 The radiation subsystem is shown according to some aspects.

[0018] Figure 5 The radiation device is shown according to some aspects.

[0019] Figure 6A and 6B An exemplary embodiment of the beam-reversing optical component and aperture is shown.

[0020] Figure 7 The aperture is shown according to some aspects.

[0021] Features of this disclosure will become more apparent when considered in conjunction with the figures, in which the same reference numerals identify corresponding elements throughout. In the figures, similar reference numerals generally denote identical, functionally similar, and / or structurally similar elements. Furthermore, generally, the leftmost (one or more) numerals of the reference numerals identify the figure in which that reference numeral first appears. Unless otherwise stated, the figures provided throughout this disclosure should not be construed as toll-on-scale. Detailed Implementation

[0022] The aspects described herein, as well as the terms "an aspect," "aspect," "exemplary aspect," "example aspect," etc., used in the specification, indicate that the described aspect may include a specific feature, structure, or characteristic, but each aspect may not necessarily include that specific feature, structure, or characteristic. Furthermore, these phrases do not necessarily refer to the same aspect. Further, when a specific feature, structure, or characteristic is described in relation to an aspect, it should be understood that, whether explicitly described or not, the implementation of other aspects related to such feature, structure, or characteristic should be within the knowledge of those skilled in the art.

[0023] Spatial terms such as “below,” “under,” “lower,” “above,” “on,” and “upper” may be used herein to conveniently describe the relationship between one element or feature as shown in the figure and another element(s) or feature(s). Spatial terms are intended to cover different orientations of the device in use or operation other than those shown in the figure. The device may be otherwise oriented (rotated 90 degrees or in other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0024] The terms “about,” “approximately,” etc., may be used herein to indicate the value of a given quantity that may vary depending on a particular technique. Depending on a particular technique, the terms “about,” “approximately,” etc., may indicate the value of a given quantity that varies, for example, within a range of 10–30% of the value (e.g., ±10%, ±20%, or ±30% of the value).

[0025] Enumerated adjectives (e.g., "first," "second," "third," etc.) can be used to distinguish similar elements without establishing order, hierarchy, quantity, or permanent numerical assignment (unless otherwise specified). For example, the terms "first target" and "second target" can be used in a similar manner as "target i" and "target j," thus facilitating the distinction between two targets without explicit order, hierarchy, quantity, or immutable numerical correspondence.

[0026] The aspects of this disclosure can be implemented in hardware, firmware, software, or any combination thereof. The aspects of this disclosure can also be implemented as instructions stored on a computer-readable medium. These instructions can be read and executed by one or more processors. A machine-readable medium can include any mechanism that stores or transmits information in a machine-readable form (e.g., a computing device). For example, "machine-readable medium" can include read-only memory (ROM); random access memory (RAM); disk storage media; optical storage media; flash memory devices; electrical, optical, acoustic, or other forms of propagating signals (e.g., carrier waves, infrared signals, digital signals, etc.). Furthermore, firmware, software, routines, and / or instructions can be described herein as performing certain actions. However, it should be understood that such descriptions are for convenience only, and such actions originate from a computing device, processor, controller, or other means of executing firmware, software, routines, instructions, etc. The term "machine-readable medium" can be used interchangeably with similar terms such as "computer program product," "computer-readable medium," "non-transitory computer-readable medium," etc. The term "non-transitory" can be used herein to characterize one or more forms of computer-readable media other than transient propagating signals.

[0027] However, it is enlightening to introduce an example environment in which the aspects of this disclosure can be implemented before describing these aspects in more detail. Photolithography system example

[0028] Figure 1A and Figure 1B Schematic diagrams of lithography apparatus 100 and 100', in which embodiments of the present disclosure may be implemented, are shown respectively. Lithography apparatus 100 and 100' each include: an irradiation system (irradiator) IL configured to modulate a radiation beam B (e.g., deep ultraviolet or extreme ultraviolet radiation); a support structure (e.g., a mask stage) MT configured to support a patterning device (e.g., a mask, stencil, or dynamic patterning device) MA and connected to a first positioner PM configured to precisely position the patterning device MA; and a substrate stage (e.g., a wafer stage) WT configured to hold a substrate (e.g., a wafer coated with resist) W and connected to a second positioner PW configured to precisely position the substrate W. Lithography apparatuses 100 and 100' also have a projection system PS configured to project a pattern imparted by the patterning device MA to the radiation beam B onto a target portion (e.g., including one or more dies) C of the substrate W. In the photolithography apparatus 100, both the patterning device MA and the projection system PS are reflective. In the photolithography apparatus 100', both the patterning device MA and the projection system PS are transmissive.

[0029] The irradiation system IL may include various types of optical components for guiding, shaping, or controlling the radiation beam B, such as refractive, reflective, catadioptric, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof.

[0030] The support structure MT holds the patterning device MA in a manner dependent on the orientation of the patterning device MA relative to a reference frame, the design of at least one of the lithography apparatuses 100 and 100', and other conditions (e.g., whether the patterning device MA is held in a vacuum environment). The support structure MT can use mechanical, vacuum, electrostatic, or other clamping techniques to hold the patterning device MA. The support structure MT can be a frame or stage (e.g., fixed or movable) as required. By using sensors, the support structure MT can ensure that the patterning device MA is in a desired position, for example, relative to the projection system PS.

[0031] The term "patterning device" MA should be interpreted broadly as any device that can be used to pattern the radiation beam B on its cross-section, such as creating a pattern at a target portion C of a substrate W. The pattern applied to the radiation beam B can correspond to a specific functional layer created in the target portion C within the device, thereby forming an integrated circuit.

[0032] Terms such as “inspection apparatus” and “measuring system” may be used herein to refer to, for example, apparatus or systems used to measure structural characteristics (e.g., overlay error, critical dimension parameters) or used in a lithography apparatus to inspect wafer alignment (e.g., alignment apparatus).

[0033] The patterning device MA can be transmissive (e.g., Figure 1B Photolithography device 100') or reflective (such as) Figure 1A (Photolithography apparatus 100). Examples of patterning apparatus include photomasks, masks, programmable mirror arrays, or programmable LCD panels. Masks are well known in the field of photolithography and include types such as binary, alternating phase-shifting or attenuation phase-shifting, and various hybrid mask types. An example of a programmable mirror array employs a matrix arrangement of small mirrors, each of which can be individually tilted to reflect an incident radiation beam in different directions. The tilted mirrors pattern the radiation beam B, which is reflected by the matrix of small mirrors.

[0034] The term "projection system" PS can encompass any type of projection system, including refractive, reflective, catadioptric, magnetic, electromagnetic, electrostatic optical systems, or any combination thereof, depending on the exposure radiation used, or other factors such as the use of a liquid immersion solution on the substrate W or the use of a vacuum. Because other gases may absorb excessive radiation or electrons, a vacuum environment can be used for EUV or electron beam radiation. Therefore, a vacuum environment can be provided throughout the optical path by means of vacuum walls and a vacuum pump.

[0035] The lithography apparatus 100 and / or lithography apparatus 100' can be of the type having two (dual-stage) or more substrate stages WT (and / or two or more mask stages). In such a "multi-stage" machine, additional substrate stages WT can be used in parallel, or preparation steps can be performed on one or more other substrate stages while one or more substrate stages WT are being used for exposure. In some cases, the additional stage may not be a substrate stage WT.

[0036] The lithography apparatus can also be of a type in which at least a portion of the substrate can be covered by a liquid (e.g., water) with a relatively high refractive index to fill the space between the projection system and the substrate. Immersion liquid can also be applied to other spaces within the lithography apparatus, such as between the mask and the projection system. Immersion techniques for increasing the numerical aperture of the projection system are well known in the art. The term "immersion" as used herein does not imply that structures such as the substrate must be submerged in the liquid, but simply that the liquid is positioned between the projection system and the substrate during exposure.

[0037] refer to Figure 1A and Figure 1BThe irradiator IL receives the radiation beam from the radiation source SO. The source SO and the lithography apparatus 100, 100' can be separate physical entities, for example, when the source SO is an excimer laser. In such cases, the source SO is not considered part of the lithography apparatus 100 or 100', and the radiation beam B is transmitted via a beam transport system BD (…). Figure 1B The beam transmission system BD (from source SO to irradiator IL) includes, for example, appropriately guided mirrors and / or beam expanders. In other cases, the source SO may be an integral part of the lithography apparatus 100, 100', for example, when the source SO is a mercury lamp. The source SO and the irradiator IL, together with the beam transmission system BD (if required), may be referred to as the radiation system.

[0038] The irradiator IL may include an adjuster AD for adjusting the angular intensity distribution of the radiation beam (in Figure 1B (In the middle). Typically, at least the outer and / or inner radial ranges of the intensity distribution on the pupil plane of the irradiator (often referred to as "σ-outer" and "σ-inner," respectively) can be adjusted. Furthermore, the irradiator IL may include various other components, such as an integrator IN and a convergent CO. The irradiator IL can be used to adjust the radiation beam B so that it has a desired uniformity and intensity distribution across its cross-section.

[0039] refer to Figure 1A A radiation beam B is incident on a patterning device (e.g., a mask) MA held by a support structure (e.g., a mask stage) MT and patterned by the patterning device MA. In the lithography apparatus 100, the radiation beam B is reflected from the patterning device (e.g., the mask) MA. After being reflected from the patterning device (e.g., the mask) MA, the radiation beam B passes through a projection system PS, which focuses the radiation beam B onto a target portion C of the substrate W. The substrate stage WT can be precisely moved (e.g., to position different target portions C in the path of the radiation beam B) using a second positioner PW and a position sensor IF2 (e.g., an interferometric device, a linear encoder, or a capacitive sensor). Similarly, a first positioner PM and another position sensor IF1 can be used to precisely position the patterning device (e.g., the mask) MA relative to the path of the radiation beam B. The patterning device (e.g., the mask) MA and the substrate W can be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2.

[0040] refer to Figure 1BA radiation beam B is incident on a patterning device (e.g., a mask MA) held by a support structure (e.g., a mask stage MT) and patterned by the patterning device. After passing through the mask MA, the radiation beam B passes through a projection system PS, which focuses the radiation beam B onto a target portion C of the substrate W. The projection system has a pupil PPU conjugate to the illumination system pupil IPU. The portions of radiation emanate from the intensity distribution at the illumination system pupil IPU and pass through the mask pattern without being affected by diffraction at the mask pattern, creating an image of the intensity distribution at the illumination system pupil IPU.

[0041] The projection system PS projects an image of a mask pattern MP onto a photoresist layer coated on a substrate W, where the image is formed by diffracted beams generated from radiation of intensity distribution from the pattern MP. For example, the mask pattern MP may comprise an array of lines and spacings. At the array, radiation diffracted, distinct from zero-order diffraction, generates deflected diffracted beams that change direction perpendicular to the lines. Undiffracted beams (i.e., the so-called zero-order diffracted beams) pass through the pattern without any change in propagation direction. The zero-order diffracted beam passes through the upper lens or upper lens group of the projection system PS upstream of the conjugate pupil PPU, reaching the conjugate pupil PPU. The partial intensity distribution within the plane of the conjugate pupil PPU and associated with the zero-order diffracted beam is an image of the intensity distribution in the illumination system pupil IPU of the illumination system IL. For example, an aperture device PD is positioned or substantially located in the plane comprising the conjugate pupil PPU of the projection system PS.

[0042] The projection system PS is arranged to capture not only the zero-order diffraction beam, but also the first-order diffraction beam, or first-order and higher-order diffraction beams (not shown), through a lens or lens group L. In some embodiments, for imaging a line pattern extending in a direction perpendicular to the line, dipole illumination can be used to take advantage of the resolution enhancement effect of dipole illumination. For example, the first-order diffraction beam interferes with the corresponding zero-order diffraction beam at the layer level of the wafer W to create an image of the line pattern MP at the highest possible resolution and process window (i.e., the combination of available depth of focus and permissible exposure dose deviation). In some embodiments, astigmatism can be reduced by providing a radiating pole (not shown) in the opposite quadrant of the illumination system pupil IPU. Furthermore, in some embodiments, astigmatism can be reduced by blocking the zero-order beam in the conjugate pupil PPU of the projection system associated with the radiating pole in the opposite quadrant. This is described in more detail in US 7,511,799 B2, published March 31, 2009, which is incorporated herein by reference in its entirety.

[0043] With the aid of a second positioner PW and a position sensor IFD (e.g., an interferometric apparatus, a linear encoder, or a capacitive sensor), the substrate stage WT can be precisely moved (e.g., to position different target portions C within the path of the radiation beam B). Similarly, the first positioner PM and another position sensor ( Figure 1B (Not shown) can be used to precisely position the mask MA relative to the path of the radiation beam B (e.g., after mechanical retrieval from the mask library or during scanning).

[0044] Typically, the movement of the mask stage MT can be achieved using a long-stroke module (coarse positioning) and a short-stroke module (fine positioning), which together form part of the first positioner PM. Similarly, the movement of the substrate stage WT can be achieved using a long-stroke module and a short-stroke module, which together form part of the second positioner PW. In the presence of a stepper (opposite to the scanner), the mask stage MT can be connected only to the short-stroke actuator or can be fixed. The mask MA and substrate W can be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2. Although the substrate alignment marks (as shown) occupy dedicated target portions, they can be positioned in the space between the target portions (referred to as scribe alignment marks). Similarly, when more than one die is positioned on the mask MA, the mask alignment marks can be positioned between the dies.

[0045] The mask stage MT and patterning device MA can be located within a vacuum chamber V, where an in-vacuum robot IVR can be used to move patterning devices, such as masks, into and out of the vacuum chamber. Alternatively, when the mask stage MT and patterning device MA are outside the vacuum chamber, an out-of-vacuum robot can be used for various transport operations, similar to an in-vacuum robot IVR. Both the in-vacuum and out-of-vacuum robots need to be calibrated to smoothly transfer any payload (e.g., a mask) to a stationary, movable mount.

[0046] Photolithography apparatuses 100 and 100' can be used in at least one of the following modes:

[0047] 1. In step mode, the support structure (e.g., mask stage) MT and substrate stage WT are kept substantially stationary while the entire pattern applied to the radiation beam B is projected onto the target portion C in a single exposure (i.e., a single static exposure). The substrate stage WT is then shifted along the X and / or Y directions so that different target portions C can be exposed.

[0048] 2. In the scanning mode, the support structure (e.g., mask stage) MT and the substrate stage WT are scanned synchronously, while a pattern applied to the radiation beam B is projected onto the target portion C (i.e., a single dynamic exposure). The velocity and direction of the substrate stage WT relative to the support structure (e.g., mask stage) MT can be determined by the magnification (or reduction) and image inversion characteristics of the projection system PS.

[0049] 3. In another mode, the support structure (e.g., mask stage) MT is kept substantially stationary to hold the programmable patterning device, and the substrate stage WT is moved or scanned while the pattern, supplied to the radiation beam B, is projected onto the target portion C. A pulsed radiation source SO can be employed, and the programmable patterning device is updated as needed after each movement of the substrate stage WT or between successive radiation pulses during scanning. This operating mode can be readily applied to maskless lithography utilizing programmable patterning devices such as programmable mirror arrays.

[0050] Combinations and / or variations of the described use patterns, or entirely different use patterns, may also be adopted.

[0051] In some aspects, the lithography apparatus 100 includes an extreme ultraviolet (EUV) source configured to generate an EUV radiation beam for EUV lithography. Typically, the EUV source is configured in a radiation system, and a corresponding irradiation system is configured to modulate the EUV radiation beam from the EUV source.

[0052] In some aspects, the lithography apparatus 100' may include a deep ultraviolet (DUV) source configured to generate a DUV radiation beam for DUV lithography. Typically, the DUV source is configured in a radiation system, and a corresponding irradiation system is configured to modulate the DUV radiation beam from the DUV source.

[0053] Figure 1CA lithography unit 110 (sometimes referred to as a lithography cell or cluster) is shown according to certain aspects. A lithography apparatus 100 or 100' may form part of the lithography unit 110. The lithography unit 110 may also include one or more devices for performing pre-exposure and post-exposure processes on a substrate. Examples of such devices may include a spin coater SC for depositing a resist layer, a developer DE for developing the exposed resist, a cooling plate CH, and a baking plate BK. A substrate processor (or robot) RO may pick up substrates from input / output ports I / O1, I / O2, move them between different process devices, and deliver substrates to the feed stage LB of the lithography apparatus 100 or 100'. These different devices (generally referred to collectively as tracks) may be controlled by a track control unit TCU, which itself may be controlled by a management control system SCS. The management control system may also control the lithography apparatus 100 or 100' via a lithography control unit LACU. Thus, the different devices can be operated to maximize throughput and processing efficiency.

[0054] Figure 2A A lithography apparatus 200 is shown according to some aspects, comprising a source SO (e.g., a source collector device), an irradiation system IL, and a projection system PS. The source SO is constructed and arranged such that a vacuum environment can be maintained within a closed structure 220 of the source SO. A plasma 210 emitting EUV radiation can be formed by a plasma source generated by discharge. In some aspects, excited tin (Sn) plasma (e.g., via laser excitation) is used to generate EUV radiation.

[0055] Radiation emitted by the EUV-emitting plasma 210 can be transmitted from the source chamber 211 into the collector chamber 212 via an optional gas barrier or contaminant trap 230 (also referred to in some cases as a contaminant barrier or foil trap) positioned within or behind an opening in the source chamber 211. The contaminant trap 230 may include a channel structure. The contaminant trap 230 may also include a gas barrier and / or a channel structure.

[0056] In some aspects, collector chamber 212 may include a radiation collector CO. The radiation collector CO may be a so-called grazing incidence collector. The radiation collector CO may include an upstream radiation collector side 251 and a downstream radiation collector side 252. Radiation passing through the radiation collector CO may be reflected by a grating spectral filter 240 to be focused into a virtual source point INTF. The virtual source point INTF may be referred to as the intermediate focus. The source collector arrangement may be such that the intermediate focus INTF is located at or near an opening 219 of the enclosed structure 220. The virtual source point INTF may be an image of the plasma 210 emitting EUV radiation. The grating spectral filter 240 may be used to suppress infrared (IR) radiation.

[0057] Subsequently, the radiation passes through the illumination system IL. The illumination system IL may include a faceted field mirror device 222 and a faceted pupil mirror device 224, which are arranged to provide a desired angular distribution of the radiation beam 221 at the patterning device MA, and a desired uniformity of radiation intensity at the patterning device MA. Once the radiation beam 221 is reflected at the patterning device MA held by the support structure MT, a patterned beam 226 is formed, and this patterned beam 226 is imaged by the projection system PS via reflective elements 228, 229 onto the substrate W held by the wafer stage or substrate WT. In some aspects, other configurations of mirrors and / or optical devices may be used to guide the radiation beam 221 to the patterning device MA.

[0058] The illumination system IL and projection system PS can typically contain more elements than shown. The grating spectral filter 240 can be optionally present depending on the type of photolithography apparatus. Furthermore, more than... Figure 2A The mirrors shown have more mirrors, for example, compared to Figure 2A As shown, there are one to six additional reflective elements in the projection system PS.

[0059] In some respects, Figure 2A and 2B The uniformity compensator UC, sensor ES, and / or measurement sensor MS shown can be described above with reference to Figure 1.

[0060] like Figure 2A As illustrated, the collector CO is depicted as an example of a nested collector with grazing incidence reflectors 253, 254, and 255 (or collector mirrors). The grazing incidence reflectors 253, 254, and 255 can be arranged symmetrically about the optical axis O. This type of collector optics can be used in combination with a discharge-generated plasma source (often referred to as a DPP source).

[0061] Figure 2B A photolithography apparatus 200 is shown according to some aspects, but it has collecting optics in the source SO. It should be understood that... Figure 2A The one shown is not in Figure 2B Structures appearing in the drawing (for clarity) can still be included in the reference. Figure 2B In this aspect, it has the same characteristics as... Figure 2A Those components with the same reference numerals in the attached drawings Figure 2B The components in the reference have Figure 2A The same or substantially similar structure and function are described. In some aspects, the photolithography apparatus 200 can be used, for example, to expose a substrate W, such as a wafer coated with resist, using a patterned EUV irradiation beam. Figure 2B In this diagram, the irradiation system IL and the projection system PS are represented as an exposure apparatus 256 using EUV light from a source SO (e.g., an integrated circuit lithography tool such as a stepper, scanner, step-scan system, direct write system, or device using a contact and / or proximity mask). The lithography apparatus 200 may also include a collector 258 that reflects EUV light from a plasma 210 emitting EUV radiation along a path into the exposure apparatus 256 to irradiate the substrate W. The collector 258 may include a near-normal incident collector mirror having a reflective surface in the form of a long ellipsoid (e.g., an ellipse about its major axis). The long ellipsoidal structure may have a gradient multilayer coating with alternating molybdenum and silicon layers, and in some cases, the gradient multilayer coating has one or more high-temperature diffusion barrier layers, smoothing layers, capping layers, and / or etch stop layers. Examples of radiation sources

[0062] Pulsed discharge radiation sources have a variety of applications. In some areas, pulsed discharge lasers can be used in photolithography, medical procedures, laser ablation, laser imprinting, etc. A photolithography apparatus is an example of a radiation source where stable operation is desired.

[0063] Figure 3 A radiation source 300 is shown according to some aspects. In some aspects, the radiation source 300 is a pulsed discharge radiation source. A gas discharge laser is an example of a pulsed discharge radiation source. The source SO of a photolithography apparatus can use the implemented radiation source 300. The radiation source 300 may include a chamber 302, a window 304, a piping system 306, and one or more electrodes 314 (also referred to as "electrical connections"). The piping system 306 may include a network of valves, pipes, and contaminant filters (not shown).

[0064] In some aspects, the gas chamber 302 may include a gas 308. Gas 308 includes at least one gas selected from nitrogen, halogen gases, and rare gases, such as fluorine, neon, krypton, argon, xenon, etc. Gas 308 may be diluted via a pressure control system (e.g., a vacuum system) that controls the pressure within the gas chamber 302. A piping system 306 is connected to the gas chamber 302. The piping system 306 may allow for the management of the gas 308 within the gas chamber 302. For example, the piping system 306 may direct the flow (e.g., circulation) of the gas 308 to a filter within the piping system 306 to purify the gas 308. Voltage / current may be supplied to the gas 308 (e.g., via one or more electrodes 310) to generate radiation 312. The voltage / current may be in pulsed form with sufficient power to excite a plasma of the gas 308. This plasma may generate radiation with a set of wavelengths depending on the energy state of the plasma. The type of gas 308 (e.g., fluorine) may determine the generated wavelengths (e.g., deep ultraviolet wavelengths). Window 304 allows radiation 312 to escape from gas chamber 302.

[0065] Figure 4 A radiation subsystem 400 is illustrated according to some aspects. In some aspects, the radiation subsystem 400 may include a discharge chamber 402, one or more electrodes 410, and a gas circulator 414. The gas circulator 414 may be a blower or an external pressure system connected via piping to the gas chamber 402. The discharge chamber 402 may include a gas. The gas 408 includes at least one gas selected from nitrogen, halogen gases, and rare gases, such as fluorine, neon, krypton, argon, xenon, or other similar substances. To generate radiation, an electrical pulse may be supplied to the gas 408 via the electrodes 410, thereby igniting the gas 408 plasma in the plasma region 416 of the gas chamber 402. The generated plasma may release radiation, thus operating as a radiation source.

[0066] In some respects, during radiation generation, gas 408 and electrode 410 can chemically interact. For example, the material in electrode 410 (e.g., copper) can chemically interact with chemical components in gas 408 (e.g., fluorine) to create dust-like byproducts (e.g., metal fluoride byproducts). These gaseous byproducts can become contaminants that absorb radiation in subsequent radiation pulses. Therefore, airflow 418 (indicated by arrows) can be implemented to optimize radiation generation by circulating the used portion of gas 408 and contaminants out of the plasma generation region while supplying unused gas for the next plasma ignition. Gas circulator 414 can generate airflow 418. Heat exchanger 422 may include one or more filters (e.g., baffles, traps, etc.) configured to collect particles (e.g., metal fluoride powder) generated by electrode 410.

[0067] Figure 5 The radiation system 500 is shown according to some aspects. In some aspects, the radiation device 500 may include a radiation generating system 520 and an amplification system 522. In some aspects, the radiation generating system 520 generates a beam 524 comprising a desired wavelength. In some aspects, the amplification system 522 receives the beam 524 from the radiation generating system 520. In some aspects, the amplification system 522 amplifies the power of the beam 524.

[0068] In some respects, the radiation generation system 520 includes a gas chamber 502, a wavelength selector 526, and an output coupler 528.

[0069] In some respects, an electrical pulse is applied to gas 508 to ignite the plasma and generate radiation 512. The molecules of gas 508 may have multiple energy levels that can decay with the release of photons (the photon wavelength corresponds to these multiple energy levels). Subsequently, a radiation beam 524 is output from the radiation generation system 520.

[0070] Narrow and stable wavelengths are advantageous for photolithography processes because wavelength instability can adversely affect the accuracy of patterns printed on the substrate. As a non-limiting example, the radiation beam 524 could have a DUV wavelength of approximately 193 nm or approximately 248 nm, which can be used in photolithography processes. Therefore, selecting a narrow-band wavelength from the multiple wavelengths generated from the plasma of gas 508 is desirable.

[0071] In some aspects, wavelength selector 526 can be used to perform wavelength selection. The wavelength selection process can rely on laser emission to further amplify the radiation at the desired wavelength compared to an unselected wavelength (e.g., a higher signal-to-noise ratio (SNR)). This process can begin by allowing radiation 512 to propagate toward wavelength selector 526 (e.g., via an implementation of one or more windows). Wavelength-dependent reflector 530 can reflect a portion of radiation 512 (with the selected wavelength) along a "gain path" while rejecting other portions of radiation 512 with non-desired wavelengths (e.g., deflecting unselected wavelengths toward the beam collector). Thus, the wavelength of radiation 512 can be narrowed to a narrow band with a peak center wavelength and a small full-width-half-maximum. In some aspects, wavelength-dependent reflector 530 can include reflective elements (e.g., one or more prisms) and diffraction elements (e.g., gratings). Wavelength selector 526 can be referred to as a wavelength narrowing device, narrowing module, narrowbanding module (LNM), etc.

[0072] In some respects, adjusting the wavelength (e.g., selecting another wavelength) can be achieved by adjusting the position of the wavelength-dependent reflector 530 (e.g., rotating the diffraction or refraction element). The diffraction and refraction elements have wavelength-dependent scattering directions. When the position of the diffraction (or refraction) element changes, different wavelengths can be aligned along the gain path, while other wavelengths are directed away from the gain path. Subsequently, the laser process can target the amplified radiation 512 at the adjusted wavelength.

[0073] Further details regarding wavelength selection are described in U.S. Patent No. 8,254,420, published August 28, 2012, which is incorporated herein by reference in its entirety.

[0074] In some respects, the "gain path" can be defined between wavelength-dependent reflector 530 and output coupler 528, where the plasma of gas 508 serves as the gain medium. Laser emission can be achieved as radiation 512 (at a selected wavelength) reflects back and forth between wavelength-dependent reflector 530 and output coupler 528 (which may have reflective properties). Output coupler 528 may include a partial reflector that allows a portion of the now-amplified radiation 512 (at the selected wavelength) to be output as a radiation beam 524.

[0075] In some respects, because radiation 512 is generated at gas chamber 502 and oscillates back and forth in gas chamber 502 to achieve intensity gain, gas chamber 502 can be referred to as master oscillator (MO) chamber.

[0076] In some respects, the line center analysis module 532 receives the beam 524 from the output coupler 528. In some respects, the beam modification optics system 534 can modify the size and / or shape of the beam 524.

[0077] In some aspects, beam 524 can be amplified by amplification system 522. In some aspects, amplification system 522 includes beam-modifying optics 536, cavity 538, and beam-directing optics 540. In some aspects, beam-directing optics 540 includes at least one of prisms, mirrors, and combinations thereof.

[0078] In some aspects, the beam-modifying optics 536 guides the beam 524 toward the cavity 538 and subsequently toward the beam-directing optics 540. In some aspects, the beam 524 can propagate from the cavity 538 toward the beam-directing optics 540 through a window. In some aspects, the beam-directing optics 540 modifies the direction of the beam 524 so that the beam 524 returns to the cavity 538. In some aspects, the beam 524 can be amplified by repeatedly passing through the amplification system 522.

[0079] In some aspects, chamber 538 includes one or more electrodes, a gain medium such as a gas, and a fan for circulating the gas. In some aspects, a second "gain path" may be defined between beam-modifying optics 536 and beam-directing optics 540, wherein the gas in chamber 538 serves as the gain medium. Laser emission can be achieved as radiation 524 reflects back and forth between beam-modifying optics 536 and beam-directing optics 540. In some aspects, beam-modifying optics 536 includes an optical coupler 542, such as a partial mirror, which can couple into beam 524 and couple out of chamber 538 a portion of the amplified radiation to form an output beam 544.

[0080] In some respects, the output laser beam 544 can be guided through the bandwidth analysis module 546 and subsequently through the pulse stretcher 548. In some respects, the pulse stretcher 548 can stretch each pulse of the beam 544 (e.g., in an optical delay unit) to adjust the performance characteristics of the laser beam. In the context of photolithography, the radiation beam 544 can be a radiation beam in a photolithography apparatus. Example of beam steering optics

[0081] In some respects, as the beam is amplified within the amplification system, the optical elements within the system are irradiated with a higher flux (or optical energy per unit area). In some respects, this higher flux can damage the optical elements.

[0082] Figure 6A The beam-directing optics 640 is illustrated in some aspects. As the beam passes through the power amplification chamber, the beam-directing optics 640 can reverse the direction of the beam. In some aspects, Figure 6A It can show a more detailed view of a portion of the radiation device.

[0083] For example, the cross-sectional view of the beam-directing optics 640 can be triangular, quadrilateral, pentagonal, or hexagonal. In some aspects, the beam-directing optics 640 may include an aperture 650, a prism 652, and a beam collector 654. The aperture 650 includes a first surface facing the incident beam 624 and a second surface opposite to the first surface. The first surface of the aperture 650 is configured to reflect the incident beam 624. In some embodiments, the first surface of the aperture 650 is a reflective coating, a metallic material, or a multilayer mirror, etc. The aperture 650 may include one or more openings 651. In some aspects, the beam-directing optics 640 reverses the direction of the incident beam 624. In some aspects, the beam-directing optics 640 may be designed to handle high-power beams, such as beams with a laser pulse energy of at least 20 millijoules (mJ).

[0084] In some aspects, prism 652 includes at least a first side 656, a second side 658, a third side 659, and a fourth side 660. In some aspects, the first side 656 includes a first surface 662 and a second surface 664 opposite to the first surface 662. In some aspects, an incident beam 624 is incident on a first facet 661 of beam-directing optics 640, and an outgoing beam 624' exits from a second facet 663 of beam-directing optics 640. In some aspects, the first facet 661 and the second facet 663 share the same plane. In some aspects, the first facet 661 and the second facet 663 extend along different planes. In some aspects, at least one of the first side 656, the second side 658, the third side 659, and the fourth side 660 includes a reflective surface.

[0085] In some aspects, aperture 650 is attached to a first surface 662 of a first side 656. In some aspects, aperture 650 is spaced from the first surface 662 of the first side 656 by a distance of up to about 40 cm. In some cases, a spacing greater than 40 cm increases the spatial accessibility of other components. In some embodiments, when the first facet 661 and the second facet 663 share the same plane, aperture 650 is flat and substantially parallel to that same plane. In another embodiment, when the first facet 661 and the second facet 663 extend along different planes, aperture 650 is bent to be substantially parallel to the two facets. In some embodiments, aperture 650 is substantially perpendicular to at least one of the incident beam 624 and the exit beam 624'.

[0086] In some respects, a first portion 666 of the incident beam 624 enters through the aperture 650 and exits the prism 652, while a second portion 668 of the incident beam 624 is reflected from the aperture 650 toward the beam collector 654.

[0087] In some aspects, prism 652 is configured to reverse the direction of beam 624 via internal reflection. The first portion 666 of the incident beam 624 can take several different internal reflection paths. For example, in some aspects, the first portion 666 is reflected from the second side 658 to the third side 659 before exiting prism 652 through aperture opening 651. In some embodiments, the second surface of aperture 650 reflects the third portion 680 of the incident beam 624 and guides the third portion 680 toward the fourth side 660 of prism 652. In some embodiments, the second surface of aperture 650 has an anti-reflective or diffuser material.

[0088] In some aspects, the first side 656 and / or aperture 650 of prism 652 are tilted at an angle 670 relative to the beam 624 to increase the surface area of ​​the first side 656 and / or aperture 650 interacting with the beam 624. In some aspects, the surface area may be increased by 30%. In some aspects, the increased surface area may reduce the flux (or energy per unit area) experienced by aperture 650 from the beam 624.

[0089] Figure 6B The diagram illustrates a beam-directing optical element 640' according to certain aspects. In some aspects, Figure 6B It can show a more detailed view of a portion of the radiation device. Figure 6B Zhongyu Figure 6A Components that share elements in the same diagram can have essentially the same function.

[0090] The beam-directing optics 640' includes an aperture 650'. Aperture 650' includes a first portion 650'A and a second portion 650'B. The first portion 650'A may include a reflective coating on a first surface 662 of a first side 656. The first portion 650'A may reflect light incident on the aperture 650' towards the beam collector 654. The second portion 650'B may include a transparent material and / or a region without any material. In some aspects, the first region of the second portion 650'B may include a transparent coating, and the second region of the second portion 650'B may be without any material. The second portion 650'B allows the radiation beam 624 to enter and exit the prism 652.

[0091] An aperture of 650 or 650' can be applied to any optical component in a lithography system. For example, an aperture of 650 or 650' can be applied to optical components in a light source, exposure apparatus, or inspection system. Another example of application is having an aperture on a chamber window or one or more lenses in a semiconductor manufacturing apparatus.

[0092] Figure 7 A front view of aperture 750 is illustrated in some aspects. For example, aperture 750 can be an embodiment of aperture 650 or 650' as described above. Aperture 750 can reduce the amount of radiation incident on the optical elements in the lithography system by reflecting a portion of the incident beam away from the optical elements.

[0093] In some aspects, aperture 750 may include a first portion 772 and a second portion 774. In some aspects, the first portion 772 may be configured to block, reflect, and / or diffuse the radiation beam, for example, toward a beam collector (e.g., beam collector 654 in FIG. 6). In some aspects, the second portion 774 may be configured to allow the radiation beam to enter and exit a prism (e.g., prism 652 in FIG. 6).

[0094] The second portion 774 may include one or more regions of aperture 750 (e.g., an opening). In some aspects, the second portion 774 may include a first region 774a and a second region 774b. In some aspects, the first region 774a and the second region 774b may be configured to allow the beam to enter and exit the prism, respectively. In some embodiments, the size D of the first region 774a and the second region 774b is in the range of about 3 nanometers to about 6 nanometers (nm). The selected range is primarily determined by factors such as the material of the optical element, the beam wavelength, and the Brewster angle. In some cases, a size smaller than 3 nanometers will reduce efficiency. In some cases, a size larger than 6 nanometers will increase peak impact.

[0095] like Figure 6A As described, in some aspects, aperture 750 may be a separate element attached to or adjacent to the surface of an optical element. A first portion 772 of aperture 750 may include metal, and a second portion 774 may include one or more openings in the metal. In some aspects, the metal may be polished. The first portion 772 may additionally include a highly reflective or diffuse coating on top of the metal.

[0096] In some respects, the aperture 750 can be a coating on the outer and / or inner surface of an optical element. For example... Figure 6B As described. Part 772 may include a high-reflectivity coating. Part 774 may include an anti-reflectivity coating. In some aspects, the high-reflectivity coating may be applied to the outer surface of the optical element, and the anti-reflectivity coating may be applied to the inner surface of the optical element. In some aspects, when the radiation beam is incident on the optical element at a Brinell angle, the anti-reflectivity coating may not be applied. The high-reflectivity coating and the anti-reflectivity coating may be wavelength-dependent (i.e., the coating is high-reflectivity / anti-reflectivity only at a specific wavelength).

[0097] Those skilled in the art will understand that an aperture such as 750 nm can be applied to the surface of any optical element in a lithography system. For example, the aperture can be applied to an optical element in an EUV or DUV light source power amplifier. The aperture can also be applied to a chamber window or one or more lenses in a lithography apparatus.

[0098] The terms “radiation,” “beam,” “light,” “irradiation,” etc., may be used herein to refer to one or more types of electromagnetic radiation, such as ultraviolet (UV) radiation (e.g., wavelengths λ of 365, 248, 193, 157, or 126 nm), extreme ultraviolet (EUV or soft X-ray) radiation (e.g., radiation with wavelengths in the range of 5–100 nm, such as, for example, 13.5 nm), or hard X-rays with wavelengths less than 5 nm, and particle beams such as ion beams or electron beams. Generally, radiation with wavelengths between about 400 and about 700 nm is considered visible radiation; radiation with wavelengths between about 780 and 3000 nm (or longer) is considered infrared radiation. UV refers to radiation with wavelengths of about 100–400 nm. In the field of photolithography, the term “UV” also applies to wavelengths that can be produced by mercury discharge lamps: G-line 436 nm; H-line 405 nm; and / or I-line 365 nm. Vacuum ultraviolet (VUV), or VUV (i.e., UV absorbed by gases), refers to radiation with wavelengths of approximately 100-200 nm. Deep ultraviolet (DUV) generally refers to radiation with wavelengths ranging from 126 nm to 428 nm, and in some applications, excimer lasers can generate DUV radiation for use in photolithography apparatuses. It should be understood that radiation with wavelengths in, for example, the 180-200 nm range belongs to radiation with specific wavelength bands, at least partially within the 180-200 nm range.

[0099] Although some aspects of this disclosure are described in the context of a lithography apparatus in integrated circuit manufacturing, it should be understood that the lithography apparatus described herein can be used in other applications, such as in the manufacture of integrated optical systems, patterning and detection of magnetic domain memories, flat panel displays, LCDs, thin-film magnetic heads, etc. Those skilled in the art will understand that in the context of such alternative applications, any use of the terms "wafer" or "chip" herein can be considered as specific examples of the more general terms "substrate" and "target area," respectively. In, for example, in a track cell (a tool typically used to apply a resist layer to the substrate and develop the exposed resist) and / or a metering cell, the substrate can be processed before or after exposure. Where applicable, the aspects disclosed herein can be applied to such and other substrate processing tools. Furthermore, the substrate can be processed more than once, for example, to create a multilayer IC; therefore, the term "substrate" as used herein can also refer to a substrate that has already included multiple processed layers.

[0100] Furthermore, although some aspects of this disclosure are described in the context of optical lithography, it should be understood that aspects of this disclosure are not limited to optical lithography. For example, in imprint lithography, the morphology in a patterning apparatus defines a pattern created on a substrate. The morphology of the patterning apparatus can be pressed into a resist layer provided to the substrate, which is then cured by applying electromagnetic radiation, heat, pressure, or a combination thereof. After the resist has cured, the patterning apparatus is removed from the resist, leaving a pattern in the resist.

[0101] It should be understood that the wording or terminology used herein is for descriptive purposes and not for limiting purposes, and therefore the terminology or terminology in this specification should be interpreted by one or more persons skilled in the art based on the teachings provided herein.

[0102] With the aid of the basic functional elements described above, this disclosure illustrates the implementation of specific functions and their relationships. For ease of description, the boundaries of these basic functional elements have been arbitrarily defined herein. Alternative boundaries may be defined provided that the specific functions and their relationships are properly performed. The foregoing description of specific aspects will so fully reveal the general nature of this disclosure that others, by applying knowledge in the art, can readily modify and / or adapt such specific aspects to suit a variety of applications without undue experimentation and without departing from the general concepts of this disclosure. Therefore, based on the teachings and guidance herein, such modifications and adaptations are intended to be within the meaning and scope of equivalents of the aspects of this disclosure.

[0103] It should be understood that the detailed description section (rather than the summary and abstract section) is intended to be used to interpret the claims. The summary and abstract section may present one or more aspects of this disclosure conceived by the inventors, but not necessarily all, and is therefore not intended to limit this disclosure and the appended claims in any way. The breadth and scope of the protected subject matter should not be limited by any of the aspects described above, but should be defined by the following claims and their equivalents.

Claims

1. A system comprising: An optical component includes a first side having a first surface and a second surface; as well as The aperture includes a first part and a second part; The first part is configured to block light from entering the optical component; The second portion is configured to allow the first portion of the beam to enter and exit the first side of the optical component; The first portion of the aperture reflects the second portion of the beam, and The aperture is positioned substantially parallel to the first surface of the first side of the optical component.

2. The system of claim 1, wherein the aperture is spaced apart from the optical component.

3. The system according to claim 2, wherein the distance from the optical component is less than 40 cm.

4. The system of claim 1, wherein the first portion of the aperture comprises a coating on the first side of the optical component.

5. The system of claim 1, wherein the first portion of the aperture comprises a reflective coating.

6. The system of claim 1, wherein the first portion of the aperture comprises a diffuse material.

7. The system of claim 1, wherein one or more regions of the second portion of the optical component include an anti-reflective coating.

8. The system of claim 7, wherein the second portion of the aperture includes one or more uncoated areas on the first side of the optical component.

9. The system of claim 1, wherein the first portion of the aperture comprises at least one of a metallic material, a multilayer mirror, or a reflective coating.

10. The system of claim 1, wherein the aperture is configured to withstand a laser pulse energy of at least 20 mJ.

11. A photolithography system, comprising: Light sources, including: Chamber; An optical component, including a first side, is configured to reverse the direction of the incident beam exiting the chamber; and An aperture, substantially parallel to a first surface on the first side of the optical component, is configured to block a portion of the incident beam from entering the optical component.

12. The lithography system of claim 11, wherein the aperture is configured to allow a laser pulse energy of at least 20 mJ.

13. The lithography system of claim 11, wherein the tilt angle of the aperture relative to the incident beam is configured to increase the surface area of ​​the aperture that interacts with the incident beam.

14. The lithography system of claim 11, wherein the aperture includes a first portion configured to block light from reaching the optical component and a second portion configured to allow a portion of the beam to reach the optical component.

15. The lithography system of claim 14, wherein the first portion of the aperture includes a first side facing the incident beam and a second side facing the optical component, the first side having a reflective material and the second side having a diffuser material.

16. The lithography system of claim 14, wherein the first portion of the aperture includes a first side facing the incident beam and a second side facing the optical component, the first side having a first reflective material and the second side having a second reflective material.

17. The lithography system of claim 14, wherein the first portion of the aperture comprises a metal plate.

18. The photolithography system of claim 17, wherein the second portion of the aperture comprises one or more openings in the metal plate.

19. The lithography system of claim 15, wherein the second portion of the aperture includes one or more regions on the first side of the optical component, the one or more regions including an anti-reflective coating.

20. The lithography system of claim 15, wherein the second portion of the aperture includes only one uncoated area on the first side of the optical component.

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