TWI706235B - Euv lithography system for dense line patterning - Google Patents

Abstract

Extreme ultra-violet (EUV) lithography ruling engine specifically configured to print one-dimensional lines on a target workpiece includes source of EUV radiation; a pattern-source defining 1D pattern; an illumination unit (IU) configured to irradiate the pattern-source; and projection optics (PO) configured to optically image, with a reduction factor N＞1, the 1D pattern on image surface that is optically-conjugate to the 1D pattern. Irradiation of the pattern-source can be on-axis or off-axis. While 1D pattern has first spatial frequency, its optical image has second spatial frequency that is at least twice the first spatial frequency. The pattern-source can be flat or curved. The IU may include a relay reflector. A PO's reflector may include multiple spatially-distinct reflecting elements aggregately forming such reflector. The engine is configured to not allow formation of optical image of any 2D pattern that has spatial resolution substantially equal to a pitch of the 1D pattern of the pattern-source.

Description

Ultra-short ultraviolet photolithography system for dense line patterning

The present invention relates to an exposure tool used in the lithography process of a semiconductor wafer, and more specifically, to a pattern configured to form parallel lines separated from each other by tens of nanometers or less on the wafer Simplify exposure tools. [Related application cases]

This application claims priority from each and every of the following US provisional patent applications: No. 62 filed on June 20, 2016 and titled "Dense Line Extreme Ultraviolet Lithography System with Distortion Matching" /352,545; No. 62/353,245 filed on June 22, 2016 and titled "Extreme Ultraviolet Lithography System that Utilizes Pattern Stitching"; filed on March 24, 2017 and titled "Temperature Controlled Heat Transfer Frame for Pellicle" No. 62/476,476; No. 62/487,245 filed on April 19, 2017 and titled "Optical Objective for Dense Line Patterning in EUV Spectral Region"; No. 62/487,245 filed on April 26, 2017 and titled "Illumination System with Flat 1D-Patterned Mask for Use in EUV-Exposure Tool" No. 62/490,313; and applied for on May 11, 2017 and titled "Illumination System with Curved 1D-Patterned Mask for Use in EUV- Exposure Tool" No. 62/504,908. This application also claims priority from the International Patent Application No. PCT/US2017/033637 filed on May 19, 2017 and titled "EUV Lithography for Dense Line Patterning". The disclosure of each of the above-identified patent documents is incorporated herein by reference. Collectively, the patent documents identified above are referred to herein as our previous applications.

The currently commercially available EUV lithography equipment (hereinafter referred to as the universal EUV system) is configured to image a photomask with an arbitrary two-dimensional (2D) pattern on a semiconductor wafer (substrate) On the rectangular area. Due to the 2D nature of the pattern that must be optically transferred and imaged from the photomask onto the wafer, the EUV system of the prior art must be implemented as a scanning system to provide relative displacement between the substrate and the photomask (the scanning system currently It is implemented by using a movable stage for the photomask and at least one or more movable stages for the substrate. Without the scanning system, the photomask pattern can be patterned with sufficient accuracy and resolution. The transfer of all the features of the to the substrate is quite complicated and will not actually be realized). The structure and operational complexity of the currently used system will inevitably and substantially increase the operating cost and reduce the number of exposed substrates per unit time, partly due to the limitation of EUV light transmission through the optical system. In addition, since pattern transfer requires a process of optical imaging in 2D, the optical element string of the existing general EUV system requires high complexity and is characterized by high complexity. For example, these systems include: six polished mirrors in the projection part of the optical element string, where the mirror surface roughness is less than 0.1 nanometer rms and the mirror alignment tolerance is less than about 1 nanometer; The structurally complex and adjustable lighting part; and the large light shield or shield with complex reflective coating. In addition, correct pattern transfer requires the use of complex combinations of alignment marks. All of this will inevitably lead to high costs for the design and manufacture of general EUV systems.

Other major problems in ensuring the commercial competitiveness of general EUV systems (which are well recognized and require practical solutions) include: (A) Insufficient optical power from the EUV light source usually equipped with general EUV systems. Currently, the typical output is about 40 W to 80 W. This problem is exacerbated by the fact that the light power delivered from the EUV light source to the mask by the illumination subsystem of the EUV system is further reduced due to the limited reflectivity of the EUV mirrors (about 70% per mirror). The illumination subsystem is also interchangeably referred to as an illumination unit (IU) or an illumination lens (IL). (B) Sensitivity to defects and/or particles on the mask. In fact, since the general EUV system is configured to image the 2D pattern from the photomask onto the wafer with high resolution, the pattern transferred to the wafer can be easily damaged by defects or particles on the photomask. In other words, every defect or particle larger than tens of nanometers on the photomask can damage the pattern printed on the wafer. (C) The extremely strict requirements on the optical aberration of the projection subsystem imposed by the 2D nature and high resolution of any pattern to be printed. The projection subsystem is also interchangeably referred to as the projection optics (PO) subsystem (also called the projection lens, PL).

The currently used alternatives to the EUV lithography process (and, in particular, include the use of Deep Ultraviolet (DUV) light (preferably with a wavelength around 193 nm and the use of immersion lenses) multiple patterning of the substrate) ) Can be less expensive but involves complex wafer processing between multiple exposures. Eventually, as the required resolution of features increases, a point where the cost of multiple patterning processes is similar to that of general EUV exposure will be reached.

For any of the above reasons, the use of these general EUV systems and/or alternative immersion systems for printing patterns with simple geometric shapes is not economically attractive. Therefore, a simplified EUV system needs to be configured. The design and operating characteristics of the simplified EUV system will not only meet the optical and mechanical requirements involved in the image transfer of the simplified mask pattern onto the semiconductor substrate, but also its cost will be beneficial to the industry.

The specific example of the present invention illustrates a dedicated 1D extremely short UV (EUV) exposure tool or a scribing machine that is specifically configured to print an array of straight lines on the patternable surface of a substrate. The specific example also provides a method for transmitting radiation through an extremely short UV (EUV) exposure tool and forming an optical image of an object (including an array of straight lines) on the substrate.

In detail, the specific example provides a 1D EUV scribing machine, which includes: an EUV source, which is configured to emit EUV radiation; and a holder, which is configured to hold a pattern source defining a substantially 1D pattern in a substantially fixed position In position; a workpiece carrier configured to move the surface of the workpiece carrier relative to a pattern source held by the holder; an IU configured to irradiate a substantially 1D pattern with EUV radiation from the source; and The PO subsystem between the IU and the workpiece stage, the PO subsystem is configured to form a 1D patterned optical image in the image surface when the image surface is being repositioned by the workpiece stage. In certain cases, the image surface is optically conjugated to the substantially 1D pattern.

The specific example also provides a 1D EUV scribing machine, which includes: an EUV source, which is configured to emit EUV radiation; a patterned source, which carries a substantially 1D pattern; and an IU, which is configured to irradiate EUV radiation from the source Substantially 1D pattern; the workpiece stage; and the PO subsystem between the IU and the workpiece stage, the PO subsystem is configured to form in the image surface when the image surface is being moved by the workpiece stage Optical image of 1D pattern. Here, the PO subsystem includes first and second reflectors, and at least one of the first and second reflectors includes first and second spatially different reflective elements. In one case, these spatially different reflective elements are spatially disconnected from each other.

Specific examples of the present invention also provide a 1D EUV scribing machine, which includes an EUV source, which is configured to emit EUV radiation; a pattern source, which carries a substantially 1D pattern; and an IU, which is configured to use EUV from the source Radiation irradiates the substantially 1D pattern; and the PO subsystem, which is configured to reduce the factor N>1 when the image surface is repositioned relative to the pattern source and when the image surface is optically conjugated to the substantially 1D pattern An optical image with a 1D pattern is formed on the image surface. Here, the scribing machine is configured such that the 1D pattern has a first spatial frequency, its optical image has a second spatial frequency, and the second spatial frequency is at least twice the first spatial frequency.

According to a preferred embodiment of the present invention, EUV exposure tools and methods are disclosed for applying new one-dimensional patterns containing parallel lines densely filled in space to select substrates (and in certain cases-already carrying optical microscopy). The pattern defined by the shadow and the substrate of the pattern that is spatially distorted under certain circumstances) are marked by photolithography.

As used herein, and unless otherwise specified, the term "one-dimensional pattern" (or "1D pattern") refers to a photomask or photomask surface defined on the surface (for use in photolithography to transfer to a selected substrate A photoresist (such as a semiconductor wafer) to create an image of this 1D pattern) and a geometric pattern that extends substantially across the surface along two axes that cross each other. The 1D pattern can change along the first axis of the pattern, and the remaining along the second axis is substantially unchanged (that is, the 1D pattern can be characterized by geometric changes along the second axis, and the value of these geometric changes does not exceed the value along the second axis. 50% of the change observed along the first axis, preferably no more than 20% of the change observed along the first axis, more preferably no more than 10% of the change observed along the first axis, or even more It is preferably within 5% or less of the change observed along the first axis, and most preferably within 1% or less of the change observed along the first axis). Examples of 1D patterns are provided by any set of spaced apart substantially identical, parallel, elongated pattern elements (such as a combination of straight parallel lines or slits in another opaque screen defined at the light mask). In certain cases, the nearby 1D pattern may form a linear (1D) characteristic with a periodically varying amplitude along a first selected axis and a constant amplitude along a second axis selected to cross the first axis. ) Grating (such as 1D diffraction grating). In addition, those familiar with the art will understand that in order to correct the imaging distortion caused by the deformation of the optical system or the substrate, the 1D pattern may still have a small change along the first axis and/or the second axis. For the purpose of the present disclosure, an element or component containing a substantially 1D pattern (regardless of the specific configuration of the element or component, for example, whether as a mask or mask) can be interchangeably referred to as a pattern source.

In contrast, the term "two-dimensional pattern (2D pattern)" is defined to mean a collection of pattern elements, and changes or changes of pattern elements must be defined along two mutually transverse axes. One of the simplest examples of 2D patterns is provided by a grid or grid (when the grid or grid has a spatial period defined along two transverse axes it forms a 2D raster). Regarding the pattern of the light mask of the light mask as disclosed herein, 1D and 2D patterns are considered to be so, regardless of the curvature of the surface of the substrate (or light mask) on which the 1D and 2D patterns are formed. For simplicity, the EUV system of the present invention (in which the specific example of the objective lens discussed here is intended to be used) is specifically and purposefully configured for imaging 1D mask patterns, and is referred to herein as a 1D EUV system. For simplicity and in comparison, an EUV system (such as a general EUV system) configured to provide imaging for 2D patterned photomasks may be referred to as a 2D EUV system.

The specific example of the present invention provides a solution for the combination of the practical problems encountered in the prior art by using the 2D EUV system:

-The current unavailability of cost-effective lithography methods and systems configured to print periodic features of 10nm (and smaller) pitches in the manufacture of advanced semiconductors is the use of The following are solved by the design of EUV exposure tools that optically image the spatially dense patterns of high-quality linear gratings (referred to as "dense lines" interchangeably in this article): 1) EUV light; 2) photomask, It (on an appropriate reticle stage) is configured to (2i) be positioned in a substantially fixed relationship with the illumination and projection subsystems of the exposure tool, and (2ii) compared with the general EUV system, without scanning, And (2iii) a substantially linear diffraction grating (which can be an amplitude grating or a phase grating) carried thereon; 3) a projection optical system with a NA of 0.40 to 0.60 and an obstruction of 20% to 40% (in terms of NA ; Pupil occlusion is therefore a square value); and 4) Scan wafer stage.

-The problem presented by the lack of correct matching overlap between the image of the mask pattern and other patterns that already exist on the wafer is caused by appropriately adjusting the scanning trajectory of the wafer stage, and by scanning and exposing the wafer. Reasonably changing the optical magnification of the mask pattern and the "magnification tilt angle" (the latter term means the linear change of the magnification across the exposure field) during the circular process is solved by using the 1D EUV system of the present invention. In this case, the problem of geometrically matching the continuous scanning exposure field and the distortion of the printed layer using the conventional tool (the operation of the conventional tool produces discontinuities between adjacent images) is achieved by scanning the wafer The solution is solved by exposing every other frame twice in the first pass, and exposing the candidate frame in the second pass.

-The persistent problem of insufficient quality stitching between directly adjacent exposure fields formed on the wafer is achieved by positioning one of the proximity mask, wafer, and intermediate image plane and properly shaping it to span The entire exposure area of the wafer is established in a spatially consistent and regular exposure method. The “blind” field diaphragm defining the periphery of the individual exposure field is included in the 1D EUV system of the present invention. In certain cases, the blind field diaphragm contains an aperture with a polygonal periphery.

-The continuity of insufficient illumination levels for exposure tools commonly used for EUV light is provided by providing first and second reflectors with (1) arrays containing polyhedral fly-eye reflectors and (2) placed in The illumination optics assembly of the relay lens between the reflector and the mask is solved in the dense line 1D EUV lithography system of the present invention. In this 1D EUV system, the shape of one of the fly-eye array reflectors better matches the projection optics assembly optimized for two-beam interference across the entire range of the pitch value that characterizes the 1D mask pattern The shape of the entrance pupil.

-The problem of the continuity of insufficient illumination levels usually used for exposure tools using EUV light is provided by providing first and second reflectors with (1) arrays containing polyhedral fly-eye reflectors and (2) their surfaces A photomask with a finite radius of curvature (ie, curved) and containing a substantially linear diffraction grating pattern thereon is solved in the dense line 1D EUV lithography system of the present invention. In this 1D EUV system, the shape of one of the fly-eye array reflectors better matches the projection optics assembly optimized for two-beam interference across the entire range of the pitch value that characterizes the 1D mask pattern The shape of the entrance pupil. In addition, this 1D EUV system is designed to image, each reflector of one of the fly-eye arrays to projection optics optimized for two-beam interference across the entire range of pitch values that characterize the 1D mask pattern Entrance pupil of the assembly.

The implementation of the idea of the present invention provides that it is configured to be optically in a cost-effective manner with high resolution (in this case, a periodic line pattern (for example) corresponds to a pitch or period of ten to twenty nanometers, compared to Preferably, it is less than 10nm, and more preferably a few nanometers (for example, 5nm or less) transfer dense line patterns to realize 10nm and 7nm node semiconductor devices (according to the international technology roadmap for semiconductors) (For example, as defined by ITRS 2.0)) exposure tools or machines. The idea of the present invention is derived from the recognition that modern high-density semiconductor wafer designs are gradually based on 1D geometric patterns. The specific example of the 1D EUV system of the present invention (specifically configured to optically image a 1D pattern from a photomask (such as a pattern representing a 1D grating) onto the substrate of interest) has a transparent structure and is superior to the general 2D EUV system. Operational advantages, the reasons are:

-Compared with the optical system of the 2D EUV system, the optical system of the 1D EUV system is substantially simplified and may include fewer mirror surfaces. This actually uses the smaller optical power required from the light source (for example, tens of watts). As low as about 20 W in one example) provides good quality exposure.

-Due to the 1D nature of the photomask pattern to be transferred to the semiconductor wafer, (a) there is no longer a need to scan the photomask stage relative to the wafer stage; therefore, the light of the specific example of the present invention The cover stage or support does not include a scanning stage with a long mechanical stroke; (b) In certain circumstances, the mask pattern defines a linear grating and can be substantially linear diffraction grating (binary pure amplitude grating, Or pure phase grating). In the specific implementation where the photomask is formatted as a phase grating, the diffraction efficiency of the 1D EUV system is greatly improved, thereby increasing the effective product yield; (c) Because the optical imaging of the 1D photomask pattern is reduced to (Basically) 1D imaging—that is, since the spatial variation of the image formed on the resist carried by the substrate only exists in one direction, the 1D EUV system requires more relaxed requirements for the optical aberration of PL ( Compared with the requirements of the conventional 2D EUV system).

-Since the optical element string of the self-system eliminates some or even multiple optical surfaces (compared to the 2D EUV system) scanning reticle stage, protective film and other elements, the cost of the proposed EUV grating machine can be much lower.

-It is also understood that since the exposure of any point on the wafer is the result of the integration of light passing through the mask at different points across the mask, smaller defects and particles on the grating pattern of the mask do not significantly affect the exposure . For example, the micron-sized particles or pattern defects on the mask will destroy the fidelity of the image printed by the 2D EUV system, but for the 1D EUV system (where the size of the exposure field is several centimeters or more) will only produce Negligible change in exposure dose.

According to the idea of the present invention, a specific example of the 1D EUV system is at least configured to perform the following operations -Utilize an EUV light source that is configured to deliver at least 20 W of optical power to an IU with a central leaf-shaped monopolar illumination pattern; -Provides that when the pitch of the image formed in the resist is 20 nanometers or less and without printing any alignment or field cut marks, the 1D pattern is placed in a predefined direction (as the case may be, In order to facilitate exposing patterns in different orientations for different layers (for example, the vertical orientation of a given 1D pattern on the first layer and the horizontal orientation of the 1D pattern on the second layer), the substrate can be rotated 90 degrees for exposure In some layers), the self-reflective or transmissive mask is optically imaged onto the substrate (preferably with a diameter of 300 mm or more); -By using a central block with a NA of 0.4 or greater and 40% or less of NA and at least 50 per hour at an irradiation dose of about 30 mJ/cm² (as measured at the wafer plane) The PL of a wafer (wph) yield rate (preferably 70 wph; more preferably 100 wph; even more preferably greater than 100 wph) defines the operation of lithographic exposure of the substrate. In one implementation, the exposure field (on the substrate) is configured as a diamond shape for reliable and repeatable stitching of directly adjacent fields; -In one implementation, the optical adjustment implemented by mag-tele shift is used; and -Ensure that the overlap between the printed layer and the underlying layer has an average +3 sigma value of 1.7 nm or less.

The details of various specific examples, parts, and components of the entire system are discussed in a number of priority provisional applications (identified above; collectively referred to as "our previous applications"). The disclosures of each of the previous applications are based on The way of reference is incorporated in the present invention.

1D EUV General illustration of concrete examples of the system

FIG. 1A and FIG. 1B show a generalized schematic diagram of a specific example 100 of a 1D EUV system configured according to the idea of the present invention. The system may include one or more EUV light sources (as shown—for example, a light source 114 operating at a wavelength of 13.5 nanometers). The system includes: an optical illumination subsystem or unit (IU), which includes a first reflector 118, a second reflector 122 and a relay reflector 126; and a PO subsystem, a reflective objective reflector including two or more than two A mirror, at least one of the mirrors has a region defining an optical obstruction (a two-lens objective lens is shown as containing a first mirror 130 and a second mirror 134, each containing a corresponding central obstruction 130A, 134A). The term optical blocking is used herein to refer to at least a part (of an optical element) within which the further transmission of light incident on the optical element to the optical element in the next line is prevented or even blocked. Non-limiting examples of blocking for the reflective objective lens as shown are provided by each of the following: (i) a through opening in the substrate of a curved mirror (such as the curved main mirror 130A), within its boundary, incident thereon The light on the mirror does not reflect further toward the bending auxiliary mirror 130B but actually transmits through the through opening, and (ii) the lack of reflective coating in the predetermined area of the mirror (essentially defining the same optical effect). The term central obstruction defines an obstruction centered on the optical axis.

The reflector 118 collects the radiation 150 emitted by the light source 114 and transmits the radiation 150 as radiation 140 to the relay lens 126 through reflection off the reflector 122. The system further includes a pattern source 144 (configured as a photomask in this example) arranged in optical communication with the IU and PO. The pattern source 144 carries a spatially dense 1D pattern and is positioned so as to be illuminated by radiation 148 delivered from the light source 114 and reflected by the relay reflector 126 to the pattern source 144 through the blocking 134A. As shown, the pattern 144 is a light shield that operates in reflection (in related specific examples, the light shield may be configured as a transmissive light shield as appropriate). It is also intended that, depending on the specific implementation of the system 100, the substrate surface of the pattern source 144 on which the 1D pattern is carried may be curved (in this case, the reflective pattern source has non-zero optical power and may be referred to as a curved pattern Source) or flat (in this case, the reflective pattern source has zero optical power and can be referred to as a flat pattern source).

In addition, the 1D pattern on the photomask can compensate for the undesirable distortion of the PO. When the 1D pattern carried by the photomask is configured as a linear diffraction grating of appropriate size, the pattern source 144 diffracts the radiation 148 incident thereon to form a diffraction including spatially different beams 152A and 152B The beams, beams 152A and 152B respectively represent the diffraction orders (in one example, +1 and -1 diffraction) and propagate toward the mirror 130 of the PO (zero-order diffraction can be properly blocked to propagate in this way. In this technology A known). In the combination, the first reflector 130 and the second reflector 134 of the PO redirect the diffracted beam to the workpiece or substrate 156 of interest through the shielding 130A to expose the image of the 1D pattern carrying the pattern source 144 thereon At least one layer of photoresist. It should be understood that, according to the idea of the present invention, the photomask is arranged in a substantially fixed spatial and optical relationship with respect to the IU and PO subsystems. This is because the position and orientation of the photomask are both selected and defined in the 1D EUV. The internal rear of the exposure tool is fixed (except for optional small adjustments that may be required to maintain focus and alignment). The term "substantially fixed" refers to and is defined in a component (such as a photomask whose mechanical support is not configured to synchronize with the movement of the workpiece-stage or wafer-stage during the operation of the exposure tool The position of the ground scanning or moving mask) can still undergo a small adjustment (the adjustment value is sufficient to correct the error in any one of focusing, magnification and alignment during the operation of the exposure tool) and/or situation.

The system may also include: a fixed size or variable aperture 160 (e.g., a variable slit of a specific shape; interchangeably referred to as "pattern blindness") properly positioned within the IU (as shown-between the mirrors 122, 126) "Or "blind field diaphragm" or simply "field diaphragm"); pupil diaphragm or aperture 164 (sized to match the desired shape of the entrance pupil of the PO); the carrier supporting the reticle Stage/mounting unit (not shown); wafer stage 156A, which is equipped with a suitable stage mover (not shown) to provide the pattern source 144 and the beams 152A, 152B to the wafer according to the needs of the lithography exposure process 156 to scan; and other auxiliary components as needed (for example, vacuum chamber, metrology system and temperature control system). The x-axis is defined as being perpendicular to the axis along which the scan is performed during system operation, and the y-axis is defined as being parallel to this scan axis. In the specific examples shown in FIG. 1A and FIG. 1B, the 1D pattern includes lines parallel to the Y axis.

The various changes proposed are within the scope of the present invention. For example, FIG. 5 schematically illustrates a specific example 170 of a 1D EUV system, in which the relay lens 126 has been removed compared with the specific example 100 of FIG. 1B. This 1D EUV system without a relay reflector is discussed in more detail below. Figure 12 provides an illustration of yet another alternative implementation of the optical element string of the 1D EUV system, where the pattern source (shown as 144' and having a non-zero curvature of the surface carrying the substantially 1D pattern) is illuminated off-axis, as discussed below .

Referring again to Figures 1A and 1B, the 1D EUVD exposure tool is additionally supplemented with a control unit (control electronic circuit), optionally equipped with a programmable processor and configured to control at least the wafer-stage (and in some In a specific example, at least one of the light source, IU, and PO subsystem) operation. (For simplicity of description, Figure 5 and Figure 12 do not illustrate the control unit.)

Lighting unit ( IU ) Instance

According to the idea of the present invention, in one of the specific examples, the IU as a whole is configured to operably correspond to the 2-mirror type (or in related specific examples) as follows and discussed in more detail in our previous application. Among them, 3-mirror type) a specific example of the PO of the astigmatic lens and optically work together with the specific example of the PO, and may include at least one reflector unit with a “fly-eye” structure. An implementation of the IU design assumes a 16.5 mm wide diamond-shaped exposure field on the image surface (for example, the surface of a workpiece (such as a wafer placed on the upper wafer-stage) in a specific case), which realizes the exposure field Stitch correctly. It is also assumed and implemented that the zero-order diffracted light beam formed at the substantially 1D pattern of the pattern source 144 is blocked, so that the optical interaction of the +1 and -1 order light beams that form an optical image of the substantially 1D pattern at the image plane Double the spatial frequency of the 1D pattern in the optical image, and also allow close to normal incident illumination. (When needed, the center block in the PO can be used, or as discussed elsewhere in this application, the zero-order diffracted beam can be properly blocked by using a dedicated radiation blocking element.)

2A, 2B, and 2C show schematic diagrams showing some details of a specific example of IU. To disclose additional details and/or specific examples in our previous application. The specific instance of luminaire 200 is configured to operate with multiple EUV radiation sources (as discussed below) and provides:

-A reasonably defined lighting pattern whose shape is selected for the maximum incoherence of light. This maximum incoherence is different for a straight line array formed with a pitch of tens of nanometers (for example, 20 nanometers to 30 nanometers). Provides contrast loss. For example, the IU and the pattern source cooperate in an operable manner to form an illumination pupil (used to be defined by the intersection of two planar shapes, such as a shape that defines a plan view, in a particular implementation—two circles or discs). PO subsystem). The goal of maintaining the highest possible contrast is achieved by guiding all EUV radiation collected by the IU from the EUV source within the boundary of the illumination pupil thus defined;

-Two first fly-eye reflectors FE1-A and FE1-B, which may have individual reflectors 210 with a diamond-shaped periphery, as shown in Figure 2B; and

-The second "fly's eye" reflector array FE2, which is configured from a block formed by the reflector 220 (having a hexagonal or circular periphery) to define the leaf-shaped aperture B24 and effectively combines multiple radiation sources 214- The radiation input LA and LB received by A and 214-B simultaneously make the optical expansion conserved, and

-The curved relay mirror as part of the lighting unit;

Each of the fly-eye arrays (FE1-A, FE1-B, FE2) of the reflector is configured to correspond to the two-dimensional respectively by using mirrors (which are alternatively called "facets" or "eyes") The array captures and reflects the radiation energy obtained from the corresponding radiation objects. Usually without the help of an additional larger viewing lens and/or reflector, this array of mirrors or facets can be called a "fly-eye reflector" (or even a "fly-eye lens", as in this technology sometimes). So called). As shown, light from light source 214-A is captured by reflector FE1-A; light from light source 214-B is captured by reflector FE1-B; light reflected by FE1-A and FE1-B is captured by FE2. Each individual mirror forms an image of the radiating object as seen from the viewpoint of that individual mirror position. In other words, there is a unique element in FE1-A or FE1-B (but not at the same time) associated with each element of FE2. Therefore, if configured, each of the individual mirrors of FE1-A and FE1-B has a corresponding mirror in the FE2 array. For example, the individual reflector 210-i of the array FE1-A forms an image of the light source 214-A at the individual reflector 210-i of the array FE2, and the individual reflector 210-j of the array FE1-B is at the individual reflector 210-i of the array FE2. The individual reflector 210-j forms an image of the light source 214-B.

In the design discussed above, there are only three sequential reflections of the light beam propagating through the illuminator, when compared to the more complex designs of the prior art, since each mirror usually has a reflectivity of only 65% to 70% , Which leads to a significant improvement in optical transmission. Compared with the existing design used in general EUV machines, the number of reflections is about half, so the amount of light transmitted via the IU of the specific example of the present invention is approximately doubled compared to that of the general EUV system. In fact, the transmittance through the system can be estimated as a value of X^N, where X is the typical reflectance (65% to 70%) and N is the number of reflections. In the conventional general system, the IU has at least five (or more than five) mirrors, and the specific example of the present invention includes as few as three mirrors. Therefore, the IU transmission increases from 11% to 17% (for a general EUV system with 5 mirrors) to 27% to 34% for the specific example of the present invention. The effect is even more obvious after considering the PO subsystem. The PO subsystem uses about six mirrors in a general EUV system and only two mirrors in the specific example of the present invention. In this situation, the transmittance of 0.9% to 2% for a typical general EUV system (which includes transmission via IU and PO, but does not include the presence of a photomask) increases by an order of magnitude to 12% when using the specific example of the present invention To 17%.

的光學擴展，其中N _FE為FE2陣列中的個別鏡的數目（及FE1-A及FE-B中的個別鏡的總和）。 Further refer to Figure 1, Figure 2A, Figure 2B, in Figure 2D schematically shows the first-order layout of the IU, in which the mirror elements (each with a designated surface area ai and focal length fi) are drawn as equivalent lens elements for simplicity of explanation . Generally speaking, it should be understood that multiple arrays of FE1 mirrors are used to multiplex the light received from multiple light sources to provide the equivalent of IU

The optical extension of _FE , where N _FE is the number of individual mirrors in the FE2 array (and the sum of individual mirrors in FE1-A and FE-B).

In fact, the number of individual mirror elements in the FE2 array can be determined based on considerations of the required uniformity of light at the mask 144 and the filling of the PO's entrance pupil. In a specific example, the FE2 mirror array includes 98 hexagonal elements 220 (as shown in FIG. 2C), each of which has an angular width of 0.01996 radians as seen from the position of the wafer 156. The solid angle subtended by each of the 220 elements (as seen from the wafer) is 3.451e ^-4 steradian, which results in an elemental optical expansion of 0.04698 mm ² sr (for a 16.5 mm wide field with a regular rhombus) (Associated with each of 220 elements), and a total optical extension of 4.604 mm ² sr for the entire FE2 array.

The angular size of the individual elements 210 of the array FE1-A (or FE1-B, each of which has 98/2=49 individual micromirror elements) can be learned from the angle of the individual elements of the FE2 array and the size of the light source Next assessment:

分別表示FE1及FE2的個別鏡元件所對的角度。雙撇號表示其為所成像所對的角度。

表示自光瞳至影像平面的距離，且

表示自源至FE1的距離。 among them

Respectively indicate the angles facing the individual mirror elements of FE1 and FE2. The double prime indicates the angle to which the image is being imaged.

Represents the distance from the pupil to the image plane, and

Indicates the distance from the source to FE1.

In order to complete the evaluation of the first-order design of the 1D EUV system, additional free parameters are selected: In a specific implementation, the distance from the light source to the corresponding FE1 array is selected to be t ₀ =500 mm; the relay lens 126 and the grating mask 144 are separated The distance of is selected as t ₃ =1 meter, and the distance between the FE2 array and the relay lens 126 (corresponding to the unit magnification imaging situation) is t ₂ =t ₃ +t ₄ . The distance from FE1 to FE2 is t ₁ =d ₂ *t ₀ /d _S of about 872 mm. It should be understood that other sets of free parameters can be used to design relevant specific examples.

=39.7毫米； -    FE2寬度（六邊形的平大小至平大小）：d ₂=d ₂p*t ₂/(t ₃+t ₄) = 7.24毫米； In addition, the horizontal dimensions of the FE1-A, FE1-B, and FE2 arrays are set as follows:-FE1 width (corner to corner of the rhombus): d ₁ = t ₀

=39.7mm;-FE2 width (the flat size to flat size of the hexagon): d ₂ =d ₂ p*t ₂ /(t ₃ +t ₄ ) = 7.24 mm;

The total size across the FE1-A (or FE1-B) array is 8 elements, each of which is 39.7 mm wide (corner to corner) in the specific example, as shown in Figure B-2, which totals approximately 317.6 in the x direction Millimeters wide, or 9*39.7/sqrt(2)=252.65 millimeters along an axis inclined at 45 degrees relative to the x-axis in Figure B-2. Generally speaking, the width of the FE1 array along the x-axis is generally between 10 mm and 300 mm.

Width of the FE2 array: In the particular implementation of Figure 2C, there are 7 individual 220 mirror elements across the array, each 7.24 meters wide, resulting in the FE2 array having a width of 50.68 mm along the x-axis as shown. However, generally speaking, the "waist" of the FE2 array is between 10 mm and 300 mm, preferably between 30 mm and 70 mm.

The width of the relay lens 126 is 1 meter away from the mask 144, and the relay lens 126 faces 0.125*0.429 radians in the x direction and the y direction. Under certain conditions, the mask 144 is 6*16.5=99 mm wide (corner to corner), resulting in a size of 215 mm by 520 mm of the relay lens 126. However, generally speaking, the size of the relay lens 126 is within a range between 100 mm by 700 mm and 300 mm by 400 mm.

；一般而言，在0.01屈光度與100屈光度之間； （B）對於中繼鏡126：在一個具體實例中

； （C）對於陣列FE2：在一個具體實例中

； 大體在0.01屈光度與100屈光度之間。應理解，術語光功率為透鏡、鏡或其他光學系統的特性，其界定此系統會聚或發散入射於其上的光的空間分佈所達到的程度。光功率的量測值等於與光學系統的焦距值互逆的值。 In a specific example, the optical power of the mirror is selected as: (A) For the array FE1: in a specific example

; Generally speaking, between 0.01 diopter and 100 diopters; (B) For relay lens 126: in a specific example

; (C) For array FE2: in a specific example

; Generally between 0.01 diopter and 100 diopter. It should be understood that the term optical power is a characteristic of a lens, mirror, or other optical system, which defines the degree to which the system converges or diverges the spatial distribution of light incident on it. The measured value of optical power is equal to the reciprocal value of the focal length of the optical system.

It should be understood that the proposed specific example of IU provides an image plane between the FE-2 reflector 122 and the relay lens 126. This plane is optically conjugated to both the mask 144 and the plane of the wafer 156, and an appropriate position is provided to locate (variable in size as the case may be) aperture 160 to control the dose of radiation power delivered to the mask 144 and define it on the wafer The boundary of the exposure field formed at

The additional relevant specific examples of the IU configured according to the idea of the present invention (and in detail, the specific example configured to operate with a single EUV radiation source only) are in our previous application (and in detail, in U.S. Provisional Application No. 62/490,313 and 62/504,908).

Examples of projection optics subsystems

In a specific example, a 1D EUV system for projection lithography is configured to use a PO part including a 2-mirror system. The PO part is supplemented by a mask carrying a substantially 1D mask pattern on a flat surface (for example, the mask is formed by defining a 1D reflective diffraction grating on a planar parallel substrate). The PO in this specific example is configured to include a 2-mirror, monopole (ie, the distribution of light at any pupil plane includes a "pole" or illumination area) lighting subsystem. In a related specific example, the PO includes a 3-mirror eliminator lens.

In one particular implementation shown in Figure 3A, for example, a 1D EUV system includes a 1D EUV system configured to provide 6x reduction or reduction (due to imaging, mask pattern), NA=0.4, and 16.5 mm on wafer (Diameter) x 5 mm diamond exposure (16.5 mm means the field width in the X direction perpendicular to the scanning direction; 5 mm means the field length in the Y direction, the Y direction is parallel to the scanning movement of the printed circuit and the wafer stage In the case of the two-mirror system 300 of de-astigmatic projection optics for optical imaging, when coaxial illumination is used, the aberration in the diamond exposure is small (about 12 millimeter waves or less). The selected shape of the diamond exposure field is suitable for stitching the adjacent fields. The main mirror 310 of this design has a diameter of about 583 mm. The aspherical distributions of the mirrors 310 and 320 are mainly rotatably symmetrical and have minimal astigmatism terms. In the case of coaxial illumination, the coma-shaped term is not used, but the coma-shaped term can be introduced in the specific case of off-axis illumination. The system further utilizes a flat mask separated from the auxiliary mirror at a distance between about 800 mm and 2000 mm (as shown-about 1400 mm). The entrance pupil of the system 300 is located about 2.175 meters away from the mask of the 1D EUV system (near the wafer/substrate), and the distance from the mask to the mirror 310 is about 1 meter. The parameters of Renick's aberration used in the simulation of the system 300 are listed in FIG. 3B). In the 1D EUV system implemented in this way, the light beam from the light source undergoes interaction with only six reflectors after propagating toward the target substrate (two reflections at the reflector array of the IU and one reflection at the relay lens ; One reflection at the reflective mask; and two reflections at the PO mirror), thereby reducing the optical power loss after reflection compared with the 2D EUV system, and therefore, reducing the output power response to the EUV light source What a high demand. (In fact, in a typical 2D EUV system, the light beam is reflected at least twelve or more times by the reflector that forms the optical element string of the system.)

Since the pattern on the photomask contains a 1D grating, the incident light is roughly diffracted in the XZ plane. Therefore, each of the mirrors 310, 320 can be configured as two independent segments that provide the necessary part of a theoretically continuous ring-shaped curved reflective surface.

In a related specific example, a main mirror with a diameter of 835 mm and other components as described above are used to implement another flat field 6x reduction, which is then scaled up to a field diameter of 26 mm.

In another related embodiment, the combination is achieved by defining a 1D mask pattern on a curved substrate (ie, on the surface of a substrate with a non-zero curvature value (and therefore a finite radius of curvature); for example, on a concave surface) The formed mask utilizes a 2 or 3 mirror PO subsystem. The wavefront curvature of the radiation incident on the mask changes after interacting with the mask.

Generally speaking, the PO subsystem has a reference axis and is configured to receive EUV radiation transmitted via IU from a reflective pattern source and start at the pattern source by using a beam of EUV radiation that is incident on the pattern source With only two radiation beams of, the reduction factor N>1 is used to form an optical image of a substantially 1D pattern of the pattern source on a plane optically conjugate with the pattern source. Generally speaking, the PO subsystem is configured to reduce the contrast of the optical image in a manner that is not dependent on spatial frequency.

Additional details and/or related specific examples of the PO subsystem configured according to the idea of the present invention are disclosed in our previous application. In some specific examples, the PO subsystem is designed to tolerate a certain level of optical aberration in an operable manner. In other words, the PO subsystem may have residual optical aberrations, and if present, the residual optical aberrations may include one or more of the following: curvature of field not exceeding 100 microns; spherical aberration not exceeding 0.1 waves, coma Any one of aberration and astigmatism; and distortion not exceeding 20%. In some specific examples, the PO subsystem includes a first reflector and a second reflector, the first reflector has a first radius of curvature, the second reflector includes a second radius of curvature, and the first radius of curvature and the second radius of curvature have Opposite sign. The PO subsystem may include a reflection system including main and auxiliary mirror systems. At least one of the main and auxiliary mirror systems includes two reflection elements that are spatially different (for example, spatially disconnected) from each other (as in my previous application) The case and the details are described in detail in U.S. Provisional Application No. 62/487,245). The specific implementation of this PO subsystem will be understood from the schematic diagrams in Figs. 13A and 13B. In Figs. 13A and 13B, the components of the IU (specifically, the relay reflector 126) and the main reflector of the PO subsystem ( Marked as M1) and the auxiliary reflector of the PO subsystem (marked as M2) each include two reflecting elements (M1-A, M1-B; and M2-A, M2) that are not only spatially different but also spatially separated from each other -B). Considering the symmetry of the 1D pattern on the pattern sources 144, 144', the gap between the two reflective elements of the reflector of the PO subsystem is preferably arranged along the direction of the 1D pattern (when the pattern is formed by a 1D diffraction grating In the case of, for example, the gap or split between the elements M1-A and M1-B is substantially parallel to the line of the 1D diffraction grating). In some specific examples, the reflection elements constituting the PO subsystem reflector are symmetrical to each other about the plane containing the reference axis of the PO subsystem. In another specific example, the reflective surface of at least one of the reflective elements from a pair of reflective elements forming a given reflector of the PO subsystem is defined as a surface that can be rotationally symmetric about the reference axis of the PO subsystem. Part.

Pupil construction element

Although the elements of pupil construction are detailed in our previous application, here are some criteria and parameters specific to specific implementations.

，對應於IU的光學擴展可以

評估。 Based on the examples of the PO and IU parameters presented above, the pupil construction and related dimensions of the specific example of the present invention are illustrated in FIGS. 4A and 4B. There is a regular diamond-shaped field of 16.5 mm wide at the wafer (that is, a square field with a diagonal of 16.5 mm oriented at 45° to the X and Y axes) and assumes that the light comes from the light source (114, 214-A; 214-B) The solid angle entered by the radiation is

, The optical extension corresponding to IU can

Assessment.

Refer further to Figures 1 and 2A: it should be understood that the specific example 100 (with details from 200) is appropriately configured to provide optical elements 118 (FE1-A, FE1-B), 160 (blind field diaphragm), 144 (Photomask) and the surface associated with the wafer-stage 156A (for example, the surface of the wafer 156 supported by the wafer stage) are optically conjugate elements as understood in the art, because One of these elements irradiated with light incident thereon is optically imaged to the point of the other of these elements via the optical system of the specific example 100. The specific example is configured to form an image of overlapping FE1-A and FE1-B at the mask element 144. The specific examples 100 and 200 are also configured so that the light source 114 (214-A, 214-B), the element 122 (FE2) and the aperture stop (of the PO subsystem) are optical conjugates. It should be understood that FIG. 1B is a schematic diagram, and the divergence or convergence of a specific light beam after being reflected or transmitted through the specific optical element of the system 100 (the degree may vary depending on the specific detailed design of the system 100) It may not be accurately represented in the diagram. For the disclosure of additional details of pupil construction, readers refer to our previous applications (the disclosures of each of which are incorporated herein by reference), and for details refer to U.S. Provisional Application No. 62/487,245 number.

1D EUV General diagram of relevant concrete examples of the system

FIG. 5 schematically illustrates a specific example 500 of a 1D EUV system, in which, compared with the specific example 100 of FIG. 1B, the relay lens 126 has been removed, and the photomask 144' carrying the grating pattern (in the photomask holder , Not shown) The surface of the substrate has a non-zero curvature, and therefore has a non-zero optical power. When the reticle 144' is configured to operate in reflection, the reticle 144' images the FE2 reflector 122 into the entrance pupil of the PO subsystem. After being transmitted from the light source 114, the radiation beam 510 crosses the radiation beam diffracted by the mask pattern toward the PO subsystem (as shown schematically using the dotted line EE) and crosses very close to the mask 144' (as shown ) Or alternatively a field diaphragm 160' placed very close to the wafer 156. The proximity distance separating the field diaphragm 160' and the mask (or wafer) is generally shorter than 3 mm, preferably shorter than 1 mm, more preferably shorter than 100 μm, and even more preferably shorter than 50 μm .

Blind field diaphragm (pattern blind) Referring to Figs. 8A, 8B, and 8C, the blind field diaphragm 160 of the system defines exposure fields 810, 820, 830 that are configured to determine the beam size so as to form a substantially polygonal shape ( The optical aperture on the image surface 156), in certain cases—a diamond shape (shown as a diamond shape 810 in FIG. 8A) or a hexagonal shape (820 in FIG. 8B). The intended exposure field (and therefore the exposure field forming the optical aperture) may be defined by a concave polygon (830 of Figure 8C). Therefore, for example, the periphery of the aperture 160 of the specific example 100 is substantially defined by a polygon. This configuration solves the practical problem of providing effective spatial overlap between directly adjacent exposure fields to create a uniform exposure area across the entire image surface/wafer 156. In detail, as understood by those skilled in the art, the polygonal shape promotes effective geometric stitching of images from the subsequently formed exposure field. For example, the orientation of the example exposure field shown on the substrate 156 in FIG. 8A is such that the diagonal of the polygonal exposure field 810 is parallel to the x-axis and y-axis of the system. Although the aperture 160 is shown in FIG. 1B as operating in transmission, it should be understood that the pattern blind 160 may be configured to reflect light within the boundary of the polygonal periphery of its optical aperture in related specific examples.

It should be understood that depending on the specific type/shape of the polygonal exposure field, more than two exposure passes across the image surface may be required to fully and cleanly expose the image surface without leaving any unexposed patches. For this purpose, one advantage of having an exposure field shaped according to the specific example 830 (which would require 6 passes to complete the exposure cycle) is that this implementation will allow the entire system to be more tolerant of field-dependent aberrations.

Additional details and/or specific examples are discussed in our previous application and are discussed in detail in U.S. Provisional Application Nos. 62/352,545 and 62/353,245.

The size of the pattern blindness does not affect the exposure time and should be selected to match the total optical expansion of the illumination source. The scanning speed of the wafer stage is inversely proportional to the width of the pattern blind aperture measured along the x-axis. In some cases, pattern-blind apertures with high aspect ratio shapes (wide in X and very thin in Y) (for example, with an aspect ratio of 5 to 1 or higher) may be preferable.

The optical output required by the light source that the 1D EUV system of the present invention can be equipped with understandably depends on the amount of radiant power necessary to correctly expose the resist on the wafer and the economic output rate.

EUV Source and radiated power considerations

An example of a light source used with the 1D EUV system of the present invention can be driven by a plasma-based light source such as, for example, the laser described in US 8,242,695 and/or US 8,525,138 (laser pumping) At least part of the plasma light source) is provided. The disclosure of each of these patent documents is incorporated herein by reference. If necessary, the housing of the plasma source may be electrically grounded and/or reconfigured to change the total optical power delivered through the window of the source. As a heat source, this light source emits radiation in the UV spectral region, the visible spectral region and the IR spectral region.

Although the total power of this source emitted in a solid angle of 4π steradian can be estimated to be about 10 W based on the power so that the light source passes through its clear aperture, the applicable output from any light source suitable for the specific example is only The output delivered to the aperture of the illuminator 200. It is worth noting that the radiant power output from the light source required for the correct operation of the total 1D EUV system also depends on the execution rate of the system (for example, measured by the number of wafers (wph) processed in one hour) . The example of the graph representing the estimated required radiant power output according to the variation of the execution rate in the 1D EUV system is established based on the following assumptions: a target execution rate of 100 wph; for a total dose of 30 mJ/cm² for wafer Double pass of each part; square exposure field (oriented at 45° to the x-axis and y-axis, measuring 16.5 mm along two diagonals, see 210 in Figure 2B); 5 per wafer Seconds of additional burden time (main wafer exchange and alignment measurement); a total of 5 seconds of acceleration time per wafer; a minimum of 30 pulses for each exposure area; each has a 65% reflectivity at the mask Six reflective surfaces with 50% diffraction efficiency; and additional "geometric factors" that may be 50% lost due to mismatched optical expansion between the illuminator and the PO. In other words, the "geometric factor" is the fraction of the source output power directed into the PO entrance pupil. The graph shows the required power at the entrance of the illuminator for a given execution rate, as well as the required pulse repetition rate and wafer stage acceleration. Figure 6 shows parts of this figure for specific values of assumed parameters and for three different values of geometric factors. Table 1 additionally summarizes the results.

Table 1: Results of the execution rate model: exacutive rate Lighting power, W Repetition rate, kHz Average acceleration of the stage, g Scanning speed, mm/sec 100 43 0.60 0.50 165 80 32 0.45 0.37 122 60 twenty three 0.31 0.26 86 40 14 0.19 0.16 54 20 7 0.09 0.08 25 10 3 0.04 0.04 12

，其中

為單個光源的光學擴展。 It should be appreciated that depending on the specific choice of light source used with the specific instance of the 1D EUV system, the optical extension of this source may be less than that of an IU. In this case, the system can be configured for use with multiple light sources (eg, 214-A and 214-B as shown in Figure 2A). The number of (otherwise the same) light sources required in this case can be estimated as

,among them

It is the optical expansion of a single light source.

Additional details and/or specific examples of EUV radiation sources that are reasonably configured for operation in the 1D EUV system of the present invention are discussed in our previous application. For example, in FIGS. 9A and 9B, examples of light collection schematic diagrams of this EUV source used with the optical system of a 1D EUV exposure tool are shown. Figure 9A illustrates the configuration of a laser-driven plasma light source with an ellipsoidal mirror for refocusing EUV radiation from LPP to IF (which in turn serves as a light source for a specific example of the IU of the present invention). The 5 sr collector and 1.6 sr sub-aperture configuration are shown schematically for comparison. 9B is a schematic diagram illustrating a ray-based model of the laser driven plasma source of FIG. 9A with a collector 910 having a central opening 910A, a tin injector 214 and an auxiliary light source IF 916.

The specific model of the EUV source of FIGS. 9A and 9B includes an aperture and a blocking mask (formed by a combination of two circles and rectangles) that set the boundary of the Gaussian irradiance distribution of light proportional to the distance from the IF 916 .

The model further includes the following effects: i) the three-dimensional (3D) distribution of the plasma emission 918; (ii) the elliptical mirror image difference, obstruction, and reflectivity change; (iii) the obstruction caused by the tin jet 214. The model of the source is further assumed to have: a) a 650 mm diameter ellipsoidal collector; b) a source with an NA defined by a solid angle of 5 sr; c) a 90 μm diameter at FWHM (or at 1/e2 level) (About 910 microns below) the plasma 918 radiation distribution of about Gaussian projection. The results of simulated projection with this distribution of FRED® are presented in Figure 9C and Figure 9D; d) IF 916 with NA of 0.25; e) 20% central disk-shaped occlusion 910A (about 130 mm diameter); and f) 15% linear shading (100 mm width) caused by tin jet 914. The reflectance of the collector 910 is assumed to be about 50%, and the effective diameter of the IF 916 (considering the instability of the plasma source driven by the laser) is assumed to be about 2 mm. The modeled spatial distribution of the light generated by the plasma source and the modeled spatial distribution at the plane of the IF 916 can be self-explanatory of the intensity distribution in Figure 10A, Figure 10B, and the ray point at the plane of the IF 916 shown in Figure 11A The pattern and the pattern evaluation of the ray direction at the same plane as shown in FIG. 11B.

Considerations for the lithography process using specific examples of the present invention

When the mask (photomask) 144 used in the specific example of the 1D EUV system of the present invention is configured as a phase shift mask (PSM) to increase the contrast of the image formed at the substrate, it is different from the conventional 2D EUV. Compared with the features implemented by the system, the resulting features of the printed image are improved.

The simulation of the proposed 1D EUV system was performed under the imaging simulation conditions outlined in Table 2. For comparison, the relevant parameters of the prior art 2D EUV system are also listed. parameter Specific examples of 1D EUV tools 0.33- NA tool (previous technology 2D EUV tool ) 0.55-NA tool (previous technology 2D EUV tool ) feature 10nm line on 20nm pitch Mask type Chrome-free PSM (phase shift mask) Duality Duality illumination Center ellipse (Figure 2B, Figure 2C), σ=0.1 width by 0.4 length Dipole, 0.2σ wide on 0.9σ circle Dipole, 0.2σ wide on 0.6σ circle Center block 30% (less than 40%) no 20% Aberration From design no no Table 2: Imaging simulation conditions.

Table 3 shows specific examples of using the proposed 1D EUV tool at 0.33 NA and 0.55 NA and the area image contrast of the 1D raster printed with the standard 2D EUV tool of the prior art. The 0.33 NA tool is completely unprintable with 20nm pitch gratings, and the imaging with the 0.55 NA tool produces lower contrast. For comparison, FIG. 7A shows the data output from the resist model by focusing on the optimal dose for the specific example of the present invention and the standard high NA 2D EUV tool of the prior art. EUVD type, PSM 0.33-NA EUV. Binary 0.55-NA EUV. Binary 20nm pitch 88% — 47% Table 3: The maximum area image contrast that can be achieved with different types of imaging.

Fig. 7B and Fig. 7C are separately directed to a 2D EUV system with a NA of 0.55 and using a binary mask, and to the specific examples of the present invention discussed above (NA=0.4, PSM) to illustrate the basis of exposure dose (in millijoules/ The dependence of the critical dimension (CD) of the pattern printed on the substrate with changes in defocus (measured in microns). Although the specific example of the present invention may require a higher exposure dose, the specific example shows a substantially smaller reduction in image quality: relatively speaking, the deterioration of the CD for a given value of defocus in the 1D EUV system is substantially less than Deterioration in the 2D EUV system. For example, as understood from the comparison of curves A and B in Fig. 7B and Fig. 7C, a defocus of about 0.05 microns causes the CD of the 2D EUV system to increase from about 11 nm to about 14.5 nm, and the 1D EUV system Only an increase from about 12.5 nanometers to about 13.5 nanometers. Those familiar with the art will easily understand the advantages of increasing contrast achieved by using specific examples of the present invention.

According to the specific examples described with reference to FIGS. 1 to 11, the concept of the 1D EUV exposure tool has been outlined. Although the specific values selected for this specific example are described, it should be understood that within the scope of the present invention, the values of all parameters can be varied within a wide range to satisfy different applications. For example, the specific example of the present invention has been described as not being telecentric at the plane of the photomask and having a fixed photomask position during exposure. However, between exposure executions, or during exposure, the mask can be moved slightly along the z axis (if necessary) to induce changes in the magnification of the image and effectively allow the exposure tool of the present invention to expand/contract the imaged 1D pattern to Used for geometric matching with patterns already printed on the substrate.

Specific examples have been described as including control circuits/processors controlled by instructions stored in memory. The memory can be random access memory (RAM), read-only memory (ROM), flash memory, or any other memory, or a combination thereof, suitable for storing control software or other commands and data. Those familiar with the technology should also easily understand that the instructions or programs that define the functions of the present invention can be in multiple forms (including but not limited to being permanently stored in a non-writable storage medium (for example, a read-only memory device in a computer (such as ROM)) , Or through the computer I/O attached to the information on a readable device (such as CD-ROM or DVD disc), variably stored in a writable storage medium (such as a floppy disk, removable flash Information on the memory and hard disk drive, or information sent to the computer via communication media (including wired or wireless computer networks) is delivered to the processor. In addition, although the present invention can be embodied in software, the functions necessary to implement the present invention can be implemented by firmware and/or hardware components (such as combinational logic, application-specific integrated circuits (ASIC), field programmable Partly or wholly embodied in a gate array (FPGA) or other hardware or a combination of hardware, software and/or firmware components.

Table 4 summarizes the advantageous operating parameters of a specific embodiment of the present invention compared to some operating parameters of a 2D EUV system. feature 0.40-NA specific example of 1D EUV tool 0.33-NA 2D EUV tool 0.55-NA 2D EUV tool Mask Phase shift Duality Mask size small 6 inches by 6 inches feature 1-D grating only multiple Lens magnification 6× 4× 4×/8× Spacing range 20-30 nm ~25nm+ ~15nm+ Feature orientation By rotating the wafer, the V and H in the two prints V and H simultaneously Alignment mark Unprinted standard Printed screen size N/A; print the entire wafer 26 × 33 mm Lens field width 16.5mm 26 mm Overlay Target ~ 2nm Advocate 5nm MMO Target 3nm MMO Projection execution rate 50 wph or greater 50 wph (assumed) 100 wph (assumed) Dose at execution rate About 30 mJ/cm2 30 mJ/cm² (assumed) The power required at the entrance of the luminaire ~20 W 80 W (assumed) 250 W (assumed) Source type Plasma discharge, Xe or Sn CO2 laser drive LPP Wafer size 300 mm 300 mm Mask stage fixed scanning Table 4

Based on the combination of the disclosure content and the disclosure content of our previous application, those familiar with the technology will easily understand various specific examples of the discussed 1D EUV system dedicated to printing arrays of straight and parallel circuits on selected workpieces. These specific examples include but are not limited to:

-Specific examples of (EUV) exposure tools, including: IU; reflector (containing a pattern source on which a substantially 1D pattern is carried; this reflector is arranged to receive the incident beam of EUV radiation from IU); A system that has a reference axis and is configured to receive radiation from an incident beam transmitted from a reflector. In a specific example, the reflector includes a phase shift mask. The PO subsystem is also configured to use the reduction factor N>1, and by using only two radiation beams starting from the incident beam at the reflector to form a 1D pattern on a plane optically conjugate to the reflector Optical image. Essentially, the 1D pattern has a first spatial frequency, and its optical image has a second spatial frequency, and the second spatial frequency is at least twice the first spatial frequency. The reflector is arranged in a substantially fixed spatial and optical relationship with respect to the IU and PO subsystems. The only two radiation beams forming the optical image do not include the radiation beam representing the specular reflection of the incident beam at the reflector. The exposure tool may further include a workpiece configured to be movable transverse to the reference axis. In certain cases, the IU includes first and second fly-eye (FE) reflectors. Additionally or in the alternative, the reflector may be positioned between the individually constituting reflective elements of the first FE reflector. Generally speaking, the PO subsystem includes first and second reflectors (the first reflector has a first radius of curvature, the second reflector includes a second radius of curvature, and the first and second radii of curvature have opposite signs). In one implementation, the PO subsystem is a reflection system including a main and auxiliary mirror system, and at least one of the main and auxiliary mirror systems includes two reflection elements that are spatially different from each other.

-Related specific examples of 1D EUV exposure tools, including: IU (with the first and second fly-eye reflectors as IU constituting reflectors); PO subsystem for optical communication with IU; reflective pattern source, which It is positioned relative to the substantially fixed spatial and optical relationship of the IU and PO subsystems and carries a substantially 1D pattern on it (the pattern source is configured to receive the radiation beam from the IU and transmit the radiation from the radiation beam to PO subsystem); and a workpiece that can move laterally relative to the reference axis of the PO subsystem. The IU may further include a relay lens arranged in optical communication with both the second fly-eye reflector and the reflective pattern source. In a specific implementation, the 1D EUV exposure tool additionally includes a field diaphragm arranged between the second fly-eye reflector and the relay lens. The field diaphragm generally defines an optical aperture with a polygonal periphery. Additionally or in the alternative, the 1D EUV exposure tool is configured such that the first fly-eye reflector, the field diaphragm, the pattern source, and the surface associated with the workpiece are optically conjugate to each other. Generally speaking, the PO subsystem includes a first mirror and a second mirror, at least one of which has a central barrier. These first and second mirrors are configured to jointly define an astigmatic optical system. In certain cases, the PO subsystem further includes a third mirror. In a particular implementation, the PO subsystem has only two reflectors. In related implementations, the PO subsystem has only three reflectors. The exposure tool can be configured so that EUV radiation from the radiation beam passes through the IU by using no more than ten reflectors (where these ten reflectors include the first and second fly-eye reflectors and the reflectors of the PO subsystem) And the PO subsystem delivers toward the workpiece along the reference axis. The pattern source of the tool is generally equipped with a pattern source support, which does not contain a structure configured to scan the pattern source in synchronization with the movement of the workpiece during operation of the exposure tool. In a particular implementation, the surface of the pattern source carrying the ID pattern may have a non-zero radius of curvature to define the non-zero optical power of the pattern source. In this case, the surface of the pattern source has a first finite radius of curvature defined in a first plane, which is transverse to the surface and contains a pattern source axis perpendicular to the surface. In addition, the surface of the pattern source may have a second finite radius of curvature defined in a second plane, the second plane transverse to the first plane and containing the axis of the pattern source. The first and second finite radius of curvature may be substantially equal to each other. The 1D EUV exposure tool may additionally include a radiation source configured to emit radiation at EUV wavelengths and positioned to be optically conjugate with the second fly's eye reflector and the entrance pupil of the PO subsystem. In one case, the radiation source contains a plasma-driven light emitter. The 1D EUV exposure tool can be further equipped with a control unit (configured in operable communication with the workpiece). The control unit contains a processor programmed to perform the following operations: (i) along the first axis (by the PO subsystem Use the self-reflective pattern source to deliver the radiation relative to the position of the exposure field formed in a plane close to the surface of the workpiece) and scan the workpiece along this first scanning track to form strips of parallel lines extending along the first axis And (ii) when the pre-existing pattern has been associated with the workpiece prior to the scan in question, the first scan trajectory is adjusted to overlap the stripe on a portion of the pre-existing pattern. In certain cases, the processor is programmed to adjust the first scan trajectory during the process of scanning the workpiece, including at least one of (a) moving along the second axis and (ii) moving along the third axis, the second The axis is perpendicular to the first axis, and the third axis is perpendicular to both the first axis and the second axis. The control unit may further cooperate with at least one of the IU and PO subsystems in an operable manner, and the processor may be further programmed to adjust the spacing of the strips of the parallel lines to deform the strips.

-Specific examples of methods used to transmit radiation via 1D EUV exposure tools. The method includes the step of transmitting the first EUV radiation (received by the first reflector of the IU of this EUV exposure tool) to the reflective pattern source of the 1D EUV exposure tool, the pattern source being substantially fixed in space relative to the first reflector of the IU Relationship. The method includes a second step of further transmitting the first EUV radiation (which has interacted with the reflective pattern source) through the surface of the reflective surface containing the first mirror. For example, this transmission may include transmitting the first EUV radiation through the central aperture or central barrier of the first mirror. In one instance, transmitting the first EUV radiation through the central barrier may include transmitting the first EUV radiation through the central aperture, the surface area of the central aperture not exceeding 40% of the area of the reflective surface of the first mirror. The action of transmission may include the first beam of the first EUV radiation colliding with the first position on the surface of the first mirror and the second beam of the first EUV radiation colliding with the second position on the surface of the same first mirror , The first position and the second position are defined on opposite sides of the first mirror with respect to the reference axis. Alternatively or in addition, the method further comprises (a) reflecting the first radiation from the surface of the pattern source on which the substantially one-dimensional (1D) pattern is carried and/or (b) it further comprises applying a reduction factor of N>1 A substantially 1D pattern optical image is formed on the target surface optically conjugate with the reflective pattern source. The step of forming an optical image includes forming an optical image using only two radiation beams initiated at the reflective pattern source due to the transfer step, and these only two radiation beams do not include the first EUV radiation at the reflective pattern source Light beam reflected by the mirror. The method may additionally include the step of forming an optical image, wherein the separation distance between two directly adjacent linear elements of the image does not exceed 10 nanometers; and preferably does not exceed 7 nanometers. In one implementation, the method further includes the step of changing the curvature of the wavefront of the first EUV radiation after the radiation interacts with the reflective pattern source. The method may further include (i) transmitting the first EUV radiation through a second mirror and partially reflecting the first radiation at a surface of the second mirror on a side relative to the optical axis of the second mirror. In this situation, the step of further transmitting and transmitting the first radiation through the second mirror collectively defines the transmission of radiation through an astigmatic mirror system having a numerical aperture of at least 0.2.

For the purposes of this disclosure and the scope of the attached patent application, the use of the terms "substantially", "approximately", "about" and similar terms with respect to descriptors near values, elements, properties, or characteristics is intended to emphasize the reference Although the values, components, properties or characteristics of, may not be accurately stated, for practical purposes, they will still be regarded as being stated by those familiar with the technology. These terms (as applied to designated characteristics or quality descriptors) mean "mostly", "mainly", "significantly", "generally", "essentially", "to a large extent", " Substantially but not necessarily exactly the same" in order to appropriately represent the approximate language and describe the specified characteristics or descriptors so that the category will be understood by those familiar with the art. In a specific case, the terms "approximately", "substantially" and "about" are used as reference values to indicate a range of plus or minus 20% relative to the specified value, preferably plus or minus 10%, or even better. Or minus 5%, the best relative to the specified value plus or minus 2%. As a non-limiting example, two values that are "substantially equal" to each other mean that the difference between the two values can be within +/-20% of the value itself, preferably within +/-10% of the value itself. Within the range, more preferably within +/-5% of the value itself, and even more preferably within +/-2% or less of the value itself.

The use of these terms in describing selected features or concepts neither implies nor provides any basis for uncertainty and is used to add numerical restrictions to specified features or descriptors. As understood by those familiar with this technology, when the measurement methods accepted in this technology are used for this purpose, the actual deviation of the accurate value or the characteristics of the value, component or property stated by it are typical The numerical range defined by the experimental measurement error can vary within the numerical range defined by the typical experimental measurement error.

For example, a reference to an identified vector or line or plane that is substantially parallel to a reference line or plane will be regarded as the vector or line or plane that is the same as or very close to the reference line or plane ( The angle deviation from the reference line or plane is regarded as a typical value in the prior art, for example, between zero and fifteen degrees, preferably between zero and ten degrees, and more preferably between zero and five degrees. Between zero degrees, even better between zero degrees and 2 degrees, and optimally between zero degrees and 1 degree). For example, a reference to the identified vector or line or plane that is substantially perpendicular to the reference line or plane will be regarded as the vector or line or line whose surface normal is in the reference line or plane or very close to the reference line or plane. Plane (where the angular deviation from the reference line or plane is regarded as a typical value in the prior art, for example, between zero degrees and fifteen degrees, preferably between zero degrees and ten degrees, more preferably at zero degrees Between 0 and 5 degrees, even better between zero and 2 degrees, and optimally between zero and 1 degree). The term "substantially rigid" when used in relation to a housing or structural element that provides mechanical support for the new invention in question generally identifies a structural element that is harder than the new invention supported by the structural element. As another example, the use of the term "substantially flat" with respect to a designated surface means that the surface can have a set size in the upcoming specific situation and expressed as unevenness and/or as generally understood by those skilled in the art. Or the degree of roughness.

Other specific examples of the meaning of the terms "substantially", "about" and/or "approximately" as applied to different practical situations may be provided elsewhere in the present invention.

A specific example of the system of the present invention includes an electronic circuit (for example, a computer processor) that is controlled by instructions stored in a memory to perform specific data collection/processing and calculation steps as disclosed above. The memory can be random access memory (RAM), read-only memory (ROM), flash memory, or any other memory, or a combination thereof, suitable for storing control software or other commands and data. Those familiar with this technology should easily understand that the instructions or programs that define the operation of the present invention can be stored in many forms (including but not limited to) permanently stored in non-writable storage media (for example, read-only memory devices in computers (such as ROM)) , Or through the computer I/O attached to the information on a readable device (such as CD-ROM or DVD disc), variably stored in a writable storage medium (such as a floppy disk, removable flash Information on the memory and hard disk drive, or information sent to the computer via communication media (including wired or wireless computer networks) is delivered to the processor. In addition, although the present invention can be embodied in software, the functions necessary to implement the present invention can be implemented by firmware and/or hardware components (such as combinational logic, application-specific integrated circuits (ASIC), field programmable Partly or wholly embodied in a gate array (FPGA) or other hardware or a combination of hardware, software and/or firmware components.

The present invention as described in the scope of patent application attached to the present disclosure is intended to be evaluated as a whole based on the present disclosure. Various changes in the details, steps and components that have been described can be made within the principle and scope of the present invention by those skilled in the art.

For example, referring to FIG. 12, there is shown a schematic diagram illustrating a part of the optical system (of the 1D EUV exposure tool of the present invention) slightly changed from the specific example of FIG. 5. (Note that, for the sake of simplicity, the schematic diagram of FIG. 12 is presented without considering the accuracy of scale, shape or mutual orientation and/or positioning of the depicted components). Here, as in the specific example 500 of FIG. 5, a pattern source 144' that carries a substantially 1D pattern (which is optically imaged onto the image surface normally associated with the workpiece 156 via the PO subsystems 134, 130) The surface is curved in space. However, compared with the specific example 500, the pattern source 144' uses the auxiliary source 916 of the optical IF (as discussed above, due to the operation of the EUV source of the system) to reach EUV radiation (shown as arrow 1210). This is called off-axis directional light. In detail, the general direction of the propagation 1210 of EUV radiation incident on the pattern source forms an oblique non-zero angle of incidence with respect to the normal 1220, which defines an axis perpendicular to the surface of the curved pattern source 144'. In certain circumstances, the angle of incidence of EUV radiation 1210 onto the pattern source 144' is selected to ensure that, for example, the projection of the average wave vector of the radiation 1210 onto the surface of the pattern source 144' is substantially parallel to the substantially 1D pattern. The axis along which the line expands. For example, in the case when the substantially 1D pattern of the pattern source is formed by a 1D diffraction grating, the incident plane of the radiation 1210 onto the pattern source 144' is substantially parallel to the grating line and the reference axis (such as the normal line 1220). ). As shown in the view of FIG. 12, the line of the substantially 1D pattern of the pattern source 144' extends along the y-axis.

Referring again to FIG. 1B, for example, it will be understood that off-axis illumination of a similar configuration of the pattern source can be used in an optical system (of a 1D EUV exposure tool) that uses a substantially flat or flat pattern source 144, and/or is in use The following reflector 126 is used in the optical system. It should also be understood that the off-axis irradiation of the pattern source (whether flat or curved as described above) can usually be performed using EUB radiation beams characterized by different collimation. For example, the off-axis irradiation of the pattern source may use a substantially collimated EUV radiation beam configuration arriving from the IU; in another non-limiting example, the EUV radiation beam may be spatially converged toward the pattern source.

Therefore, the scope of the present invention includes this mutual orientation of the IU and the pattern source in the optical system of the 1D EUV exposure tool, and the final optical element of the IU (which is an FE reflector or a relay reflector) uses the optics of the 1D EUV exposure tool The system reflects EUV radiation towards the pattern source along an axis whose projection onto the pattern carrying surface of the pattern source is parallel to the longitudinal extent of the element of the substantially 1D pattern.

The choice of off-axis illumination configuration can be beneficial to reduce the loss of imaging contrast across FOV, and in some cases is beneficial to reduce or avoid phase effects that may otherwise need to be compensated by changing the structure of the light source or the structure of the pattern source itself (The effect on the propagation of radiation from the pattern source through the PO subsystem and further towards the image surface). Considering the fact that in general, at least the acceptable variation of the structure of the pattern source used with the specific examples of the present invention is limited, and the implementation of off-axis illumination of the pattern source may prove to be actually advantageous. The substantially 1D nature of the patterns attributed to the pattern sources 144, 144' and the system is configured to ensure that the optical components do not interfere with the propagation of the +1 and -1 order diffraction through the PO subsystem (as in our previous application As discussed in the case) and the fact that the zero-order diffraction formed at the pattern source by the incident radiation 1210 is substantially blocked, in the specific example of the present invention, the requirement for a specific incident angle is slightly looser. Referring to FIG. 12, for example, in a specific example, the angle at which the radiation arriving from the IU is incident on the pattern source is in the range of about zero degrees to about 40 degrees; in related specific examples, it is about 10 degrees to about Within 30 degrees. It should be understood that these ranges merely provide examples of angular ranges. In a practical example, the incident angle or angle range from 0 to substantially 90 degrees can be used anywhere.

The disclosed aspects, or parts of these aspects, can be combined in ways not listed above. Therefore, the present invention should not be regarded as limited to the specific examples disclosed.

114: light source 118: first reflector 122: second reflector 126: Relay reflector 130: The first mirror 130A: Center block 134: The second mirror 134A: Center Block 140: Radiation 144: pattern source 144': pattern source 148: Radiation 152A: beam 152B: beam 156: Wafer 156A: Wafer stage 160: Aperture 160': field diaphragm 164: pupil diaphragm/aperture 200: Illuminator 210: reflector 210-i: Individual reflector 210-j: Individual reflector 214-A: Radiation source 214-B: Radiation source 220: reflector 220-i: Individual reflector 220-j: Individual reflector 300: Two-mirror system with anti-astigmatic projection optics 310: main mirror 320: main mirror 320: mirror 510: Radiation beam 810: Diamond-shaped exposure field 820: Hexagonal shape exposure field 830: Concave polygon exposure field 910: Collector 910A: Center opening 914: Tin Injector 916: auxiliary light source IF 918: Plasma 1210: Arrow 1220: Normal M1: The main reflector of the PO subsystem M1-A: reflective element M1-B: reflective element M2: auxiliary reflector for PO subsystem M2-A: reflective element M2-B: reflective element

The present invention will be more fully understood by referring to the following detailed description in conjunction with drawings that are generally not to scale, in which: [Fig. 1A] and [Fig. 1B] provide generalized schematic diagrams of specific examples of the present invention. [FIG. 2A] A schematic diagram illustrating a specific example of a lighting unit configured according to the idea of the present invention in a side view; [FIG. 2B], [FIG. 2C] A schematic diagram showing the reflector of the specific example of FIG. 2A in a front view; [Figure 2D] illustrates the first-order layout of the specific example of Figure 2A, where the reflector is replaced by an equivalent lens; [Figure 3A] shows a specific example of the design of projection optics; [Figure 3B] List the Rennick parameters of the design of the projection optics (PO) of Figure 3A; [FIG. 4A] and [FIG. 4B] illustrate the pupil parameter determination and related systems used in a specific example of the present invention; [Figure 5] presents an alternative specific example of the system of the present invention; [FIG. 6] A graph showing the required radiation-power output from a light source used with a specific example of the system of the present invention under specified conditions; [FIG. 7A] Provides the data output from the resist model for the specific example of the present invention and the standard high NA 2D EUV tool of the prior art by focusing on the optimal dose; [FIG. 7B] and [FIG. 7C] provide a comparison of the critical dimensions of pattern features formed by photolithography using a system adopted in the prior art and a system configured according to specific examples of the present invention; [FIG. 8A], [FIG. 8B] and [FIG. 8C] illustrate examples of the shape of the exposure field formed at the image surface by the system of the present invention. Each area of the image surface is finally scanned twice (along the arrow as shown); [FIG. 9A] Illustrates a light collection system with a laser-driven plasma light source with an ellipsoidal mirror for refocusing EUV radiation from LPP to IF (IF in turn serves as a light source for a specific example of the IU of the present invention) Configuration. For comparison, the 5 sr collector and 1.6 sr sub-aperture configuration are shown schematically; [FIG. 9B] is a schematic diagram illustrating a ray-based model of the laser driven plasma source of FIG. 9A with a collector 910 having a central opening 910A, a tin injector 914 and an auxiliary light source IF 916; [Figure 9C] and [Figure 9D] illustrate the hypothetical Gaussian distribution of the plasma source driven by the laser according to the model used for calculation; [FIG. 10A] and [FIG. 10B] respectively illustrate the angular distribution of the radiation of the laser-driven plasma source model viewed along the optical axis and the radiation of the same source in the identified cross-sectional plane transverse to the optical axis. Angular distribution of radiation; [FIG. 11A] and [FIG. 11B] respectively illustrate the rays generated by the plasma source driven by the modeled laser at the plane where the auxiliary light source passes through the convergence point of the rays reflected by the collector of the plasma source and the effects of these rays Distribution of direction cosine; [FIG. 12] A part of an optical element string schematically illustrating an alternative specific example of a 1D EUV exposure tool according to the idea of the present invention; [FIG. 13A] A perspective view schematically illustrating a specific implementation of a specific example of the PO subsystem, in which at least one of the main and auxiliary reflectors is configured according to including a plurality of reflective elements that are spatially different from each other; [FIG. 13B] is a schematic diagram that supplements the drawing of FIG. 13A by depicting the symmetry of the arrangement of the multi-reflective element reflector of the PO subsystem with respect to the extension direction of the elements of the 1D pattern of the pattern source. The size and relative ratio of the elements in the drawing can be set to be different from the actual size and ratio to appropriately promote the simplicity, clarity and understanding of the drawing. For the same reason, not all elements present in one drawing may necessarily be shown and/or labeled in another drawing.

114: light source 118: first reflector 122: second reflector 126: Relay reflector 130: The first mirror 130A: Center block 134: The second mirror 134A: Center Block 140: Radiation 144: pattern source 148: Radiation 152A: beam 152B: beam 156: Wafer 156A: Wafer stage 160: Aperture 164: pupil diaphragm/aperture

Claims (18)

An exposure device comprising: An illumination optical system configured to illuminate a mask with illuminating radiation to form positive-order diffraction and negative-order diffraction radiation, the mask having a pattern; Projection optical system, including: A convex mirror configured to reflect the positive-order diffracted radiation at a first area of the convex mirror and reflect the negative-order diffracted radiation at a second area of the convex mirror to form a corresponding The first radiation beam and the second radiation beam, and A concave mirror configured to reflect the first radiation beam and the second radiation beam so that the first radiation beam and the second radiation beam overlap on the workpiece, Wherein, when the first radiation beam and the second radiation beam are propagated to the workpiece through the exposure device, they pass between the first zone and the second zone of the convex mirror. The convex mirror. Such as the exposure device of item 1 in the scope of patent application, Wherein the projection optical system includes a plurality of mirrors, and The convex mirror is the first mirror of the plurality of mirrors, which interacts with the radiation from the illumination optical system. The exposure device as claimed in claim 1, wherein the exposure device is configured such that the radiation from the illumination optical system passes through the first optical path of the first radiation beam and the second radiation beam Two optical paths and between the first optical path and the second optical path, The first optical path of the first radiation beam is defined between the convex mirror and the concave mirror, and The second optical path of the second radiation beam is defined between the convex mirror and the concave mirror. Such as the exposure device of item 3 of the scope of patent application, where The illumination optical system includes a correction mirror, which is configured to correct the illumination radiation and is arranged between the first optical path and the second optical path. The exposure device according to the fourth item of the scope of patent application, wherein the correction mirror of the illumination optical system includes a fly-eye reflector. Such as the exposure device in the scope of the patent application, which The radiation of the positive order diffraction is radiation of the +1 order diffraction, and The radiation of the negative order diffraction is radiation of the -1 order diffraction. Such as the exposure device in the scope of patent application 1, wherein the pattern includes a one-dimensional line and space pattern. Such as the exposure device with 7 patents, of which The first reflection area and the second reflection area of the convex mirror are arranged along the pitch direction of the one-dimensional line and space pattern. The exposure device according to the 7th item of the scope of patent application, wherein the first dimension of the emitted light of the illumination optical system defined along the pitch direction is smaller than the illumination optical system defined along the direction perpendicular to the pitch direction The second size of the emitted light beam. Such as the exposure device in the scope of the patent application, which The optical path of the positive-order diffracted radiation defined between the pattern and the convex mirror intersects the optical path of the first radiation beam defined between the concave mirror and the workpiece. The exposure device as claimed in the 10th item of the patent application, wherein the optical path of the positive-order diffraction of the radiation defined between the pattern and the convex mirror is different from the optical path defined between the concave mirror and the workpiece The optical paths of the second radiation beam intersect. Such as the exposure device in the scope of the patent application, which The illumination optical system includes at least one illumination mirror, The at least one illuminating mirror closest to the pattern in the optical path of the illuminating optical system is located between the convex mirror and the concave mirror. The exposure device of the 12th item of the scope of patent application, wherein the zero-order diffracted radiation formed at the pattern reaches the illumination mirror closest to the pattern in the optical path of the illumination optical system. The exposure device according to the scope of patent application 1, which further includes a member provided between the convex mirror and the concave mirror, wherein the zero-order diffracted radiation formed at the pattern reaches the member. Such as the exposure device in the scope of the patent application, which further includes an aperture stop arranged between the convex mirror and the concave mirror. A projection optical system, including: Convex mirror, configured as: Reflecting the positive-order diffracted radiation from the diffraction pattern to the convex mirror at the first reflection area of the convex mirror, and Reflect radiation from the diffraction pattern to the negative-order diffraction of the convex mirror at the second reflection area of the convex mirror, To form corresponding first and second radiation beams, and A concave mirror configured to reflect the first radiation beam and the second radiation beam so that the first radiation beam and the second radiation beam overlap on an imaging plane, Wherein, the first radiation beam and the second radiation beam pass through the convex mirror between the first reflection area and the second reflection area on the way from the convex mirror to the image plane. Such as the projection optical system of the 16th patent application, wherein the optical path of the radiation from the diffraction pattern and the positive-order diffraction of the convex mirror and the optical path between the concave mirror and the image plane The optical paths of the first radiation beam intersect. Such as the projection optical system of the 17th patent application, wherein the optical path of the radiation from the diffraction pattern and the negative-order diffraction of the convex mirror and the optical path between the concave mirror and the image plane The optical paths of the second radiation beam intersect.

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