Method for manufacturing a diaphragm assembly

Abstract

A diaphragm for EUV lithography, the diaphragm having a thickness of not more than 200 nm and comprising a stack of layers, the stack comprising: at least one silicon layer; and at least one silicon compound layer consisting of a compound of silicon and an element selected from the group consisting of boron, phosphorus, and bromine.

Description

[0001] This application is a divisional application of the patent application with application number 201680081498.6 and invention name “Method for manufacturing diaphragm assembly” whose original applicant is “ASML Netherlands B.V.” and whose entry date into the Chinese national phase is August 9, 2018 (international application date is 2016-12-02, international application number is PCT / EP2016 / 079594). Technical Field

[0002] The present invention relates to a diaphragm, a patterning device assembly and a dynamic airlock assembly for EUV lithography. Background Art

[0003] A lithographic apparatus is a machine that applies a desired pattern to a substrate (usually on a target portion of the substrate). For example, a lithographic apparatus can be used in the manufacture of integrated circuits (ICs). In this case, a pattern forming device, alternatively referred to as a mask or reticle, can be used to generate a circuit pattern to be formed on a single layer of the IC. The pattern can be transferred to a target portion (e.g., including a portion of a die, one or more dies) on a substrate (e.g., a silicon wafer). The transfer of the pattern is usually performed by imaging the pattern onto a layer of radiation-sensitive material (resist) disposed on the substrate. Typically, a single substrate will contain a collection of adjacent target portions that are continuously patterned.

[0004] Photolithography is widely regarded as one of the key steps in manufacturing ICs and other devices and / or structures. However, as the size of features manufactured using photolithography becomes smaller and smaller, photolithography is becoming a more critical factor in allowing the manufacture of miniature ICs or other devices and / or structures.

[0005] A theoretical estimate of the limit of pattern printing can be given by the Rayleigh law for resolution, as shown in equation (1):

[0006]

[0007] Where λ is the wavelength of the radiation used, NA is the numerical aperture of the projection system used to print the pattern, k1 is a process-dependent adjustment factor also known as the Rayleigh constant, and CD is the characteristic size (or critical dimension) of the printed feature. From equation (1), it is known that the reduction of the minimum printable size of the feature can be achieved in three ways: by shortening the exposure wavelength λ, by increasing the numerical aperture NA, or by reducing the value of k1.

[0008] In order to shorten the exposure wavelength and thus reduce the minimum printable size, it has been proposed to use extreme ultraviolet (EUV) radiation sources. EUV radiation is electromagnetic radiation with a wavelength in the range of 10-20 nm, for example a wavelength in the range of 13-14 nm. It has further been proposed that EUV radiation with a wavelength of less than 10 nm may be used, for example a wavelength in the range of 5-10 nm, such as a wavelength of 6.7 nm or 6.8 nm. Such radiation is referred to by the terms "extreme ultraviolet radiation" or "soft X-ray radiation". Available sources include, for example, laser-generated plasma sources, discharge plasma sources or sources based on synchrotron radiation provided by electron storage rings.

[0009] The lithographic apparatus includes a pattern forming device (e.g., a mask or reticle). Radiation is provided through the pattern forming device or reflected from the pattern forming device to form an image on a substrate. A diaphragm assembly may be provided to protect the pattern forming device from suspended particles and other forms of contaminants in the air. The diaphragm assembly for protecting the pattern forming device may be referred to as a pellicle. Contaminants on the surface of the pattern forming device may cause manufacturing defects on the substrate. The diaphragm assembly may include a frame and a diaphragm extending across the frame.

[0010] In use, the diaphragm is required to be fixed relative to the patterning device, for example by mounting features. It is desirable to reduce the amount of space occupied by the mounting features. It is also desirable for the diaphragm to have a combination of high emissivity and low probability of failure. Summary of the invention

[0011] According to one aspect of the present invention, there is provided a diaphragm for EUV lithography, the diaphragm having a thickness of no more than 200 nm and comprising a stack of layers, the stack comprising: at least one silicon layer; at least one silicon compound layer made of a compound of silicon and an element selected from the group consisting of boron, phosphorus, bromine and sulfur.

[0012] According to one aspect of the present invention, there is provided a diaphragm for EUV lithography, the diaphragm having a thickness of no more than 200 nm and comprising a stack of layers, the stack comprising: at least one silicon layer; at least one cap layer comprising ruthenium located at the outer surface of the diaphragm; and at least one anti-migration layer comprising at least one of molybdenum and titanium adjacent to each cap layer.

[0013] According to one aspect of the present invention, there is provided a diaphragm for EUV lithography, the diaphragm having a thickness of not more than 200 nm and comprising a stack of layers, the stack comprising: at least one silicon layer and / or at least one silicon compound layer, made of a compound of silicon and an element selected from the group consisting of boron, phosphorus, bromine and sulfur; at least one cap layer located at the outer surface of the diaphragm, each cap layer comprising a material selected from the group consisting of transition metal silicides, transition metal borides, transition metal carbides, transition metal nitrides and transition metal oxides; and / or at least one transition metal layer between the cap layer and the silicon layer or the silicon compound layer, each transition metal layer comprising a transition metal selected from the group consisting of Zr, Y, Mo, Cr, Hf, Ir, Mn, Nb, Os, Pd, Pt, Re, Rh, Ru, Ta, Ti, V and W. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which corresponding reference numerals indicate corresponding parts, and in which:

[0015] Figure 1 A lithographic apparatus according to an embodiment of the present invention is shown;

[0016] Figure 2 is a more detailed view of the lithography apparatus;

[0017] Figure 3 A portion of a diaphragm assembly according to an embodiment of the present invention is schematically shown in cross-section;

[0018] Figures 4 to 6 schematically illustrates in plan view various stages of a locking mechanism using a diaphragm assembly according to an embodiment of the present invention; and

[0019] Figures 7 to 13 Diaphragms according to different embodiments of the invention are schematically shown in cross-section. DETAILED DESCRIPTION

[0020] Figure 1 A lithographic apparatus 100 including a source collector module SO according to an embodiment of the present invention is schematically shown. The lithographic apparatus 100 includes:

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

[0022] a support structure (e.g., mask table) MT configured to support a patterning device (e.g., mask or reticle) MA and connected to a first positioning device PM configured to accurately position the patterning device;

[0023] a substrate table (e.g., wafer table) WT configured to hold a substrate (e.g., a resist-coated wafer) W and connected to a second positioning device PW configured to accurately position the substrate; and

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

[0025] The illumination system IL may include various types of optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic or other types of optical components, or any combination thereof, to direct, shape, or control the radiation.

[0026] The support structure MT holds the patterning device MA in a manner that depends on the orientation of the patterning device, the design of the lithographic apparatus, and other conditions such as whether the patterning device is held in a vacuum environment. The support structure MT may use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterning device MA. The support structure MT may be a frame or a table, for example, which may be fixed or movable as required. The support structure MT may ensure that the patterning device MA is in a desired position (e.g. relative to the projection system PS).

[0027] The term “patterning device” should be broadly interpreted as referring to any device that can be used to impart a pattern to the radiation beam B in its cross-section so as to form a pattern in a target portion C of the substrate W. The pattern imparted to the radiation beam B may correspond to a specific functional layer in a device being formed in the target portion C, such as an integrated circuit.

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

[0029] Similar to the illumination system IL, the projection system PS may include various types of optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof, as appropriate for the exposure radiation used, or for other factors such as the use of a vacuum. It may be desirable to use a vacuum for EUV radiation, as other gases may absorb too much radiation. Therefore a vacuum environment may be provided over the entire beam path by means of vacuum walls and a vacuum pump.

[0030] As shown here, the lithographic apparatus 100 is of a reflective type (eg, employing a reflective mask).

[0031] The lithographic apparatus 100 may be of a type having two (dual-stage) or more substrate tables WT (and / or two or more support structures MT). In such a "multi-stage" lithographic apparatus, additional substrate tables WT (and / or additional support structures MT) may be used in parallel, or preparatory steps may be performed on one or more substrate tables WT (and / or one or more support structures MT) while one or more other substrate tables WT (and / or one or more other support structures MT) are being used for exposure.

[0032] Reference Figure 1 , the illumination system IL receives a beam of extreme ultraviolet radiation from a source collector module SO. Methods for generating EUV light include, but are not necessarily limited to, converting a material into a plasma state, the material having at least one element having one or more emission lines in the EUV range (e.g., xenon, lithium, or tin). In one such method, generally referred to as laser produced plasma ("LPP"), the desired plasma can be generated by irradiating a fuel, such as a droplet, a beam, or a cluster of a material having the desired emission line element, with a laser beam. The source collector module SO can be a laser ( Figure 1 The formed plasma emits output radiation, such as EUV radiation, which is collected using a radiation collector disposed within a source collector module. The laser and source collector module SO may be separate entities, for example when a CO2 laser is used to provide a laser beam for fuel excitation).

[0033] In this case, the laser is not considered to form part of the lithographic apparatus 100, and the radiation beam B is delivered from the laser to the source collector module SO by means of a beam delivery system comprising, for example, suitable directing mirrors and / or a beam expander. In other cases, the source may be an integral part of the source collector module SO, for example when the source is a discharge produced plasma EUV generator, commonly referred to as a DPP source.

[0034] The illumination system IL may comprise an adjuster for adjusting the angular intensity distribution of the radiation beam. Typically, at least the outer and / or inner radial extent (generally referred to as σ-outer and σ-inner, respectively) of the intensity distribution in a pupil plane of the illumination system IL may be adjusted. Furthermore, the illumination system IL may comprise various other components, such as a faceted field mirror arrangement and a pupil mirror arrangement. The illumination system IL may be used to adjust the radiation beam B to have a desired uniformity and intensity distribution in its cross-section.

[0035] The radiation beam B is incident on the patterning device (e.g. mask) MA held on a support structure (e.g. mask table) MT and is patterned by the patterning device MA. After having been reflected by the patterning device (e.g. mask) MA, the radiation beam B passes through a projection system PS which focuses the radiation beam B onto a target portion C of the substrate W. With the aid of a second positioning device PW and a position sensor PS2 (e.g. an interferometer device, a linear encoder or a capacitive sensor), the substrate table WT can be precisely moved, for example in order to position a different target portion C in the path of the radiation beam B. Similarly, the first positioning device PM and a further position sensor PS1 may be used to precisely position the patterning device (e.g. mask) MA relative to the path of the radiation beam B. The patterning device (e.g. mask) MA and the substrate W may be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2.

[0036] The controller 500 controls the overall operation of the lithographic apparatus 100, and in particular performs the operation process described further below. The controller 500 may be embodied as a suitably programmed general-purpose computer including a central processing unit, volatile and non-volatile storage devices, one or more input and output devices (such as a keyboard and a screen), one or more network connections, and one or more interfaces to various parts of the lithographic apparatus 100. It should be understood that a one-to-one relationship between the control computer and the lithographic apparatus 100 is not necessary. In an embodiment of the present invention, one computer may control multiple lithographic apparatuses 100. In an embodiment of the present invention, multiple network computers may be used to control one lithographic apparatus 100. The controller 500 may also be configured to control one or more associated processing devices and substrate handling devices in a lithographic cell or cluster, and the lithographic apparatus 100 forms part of the lithographic cell or cluster. The controller 500 may also be configured to be attached to a monitoring system of a lithographic cell or cluster and / or a general control system of a factory floor (fab).

[0037] Figure 2The lithographic apparatus 100 is shown in more detail, including a source collector module SO, an illumination system IL, and a projection system PS. A plasma 210 emitting EUV radiation may be formed by a plasma source. EUV radiation may be generated by a gas or vapor, such as Xe, Li vapor, or Sn vapor, wherein the radiation emitting plasma 210 is formed to emit radiation in the EUV range of the electromagnetic spectrum. In one embodiment, an excited plasma of tin (Sn) is provided to generate EUV radiation.

[0038] Radiation emitted by the radiation emitting plasma 210 is transferred from the source chamber 211 into the collector chamber 212 .

[0039] The collector cavity 212 may include a radiation collector CO. Radiation passing through the radiation collector CO may be focused at a virtual source point IF. The virtual source point IF is usually called an intermediate focus, and the source collector module SO is arranged such that the virtual source point IF is located at or near the opening 221 of the enclosing structure 220. The virtual source point IF is an image of the radiation emitting plasma 210.

[0040] The radiation then passes through an illumination system IL which may comprise a faceted field mirror arrangement 22 and a faceted pupil mirror arrangement 24 arranged to provide a desired angular distribution of the unpatterned beam 21 at the patterning device MA and a desired uniformity of radiation intensity at the patterning device MA. Upon reflection of the unpatterned beam 21 at the patterning device MA held by the support structure MT, a patterned beam 26 is formed and the patterned beam 26 is imaged by the projection system PS via reflective elements 28, 30 onto a substrate W held by a substrate table WT.

[0041] Typically, there may be more elements than shown in the illumination system IL and the projection system PS. Furthermore, there may be more mirrors than shown in the figures, for example, there may be more than 100 mirrors in the projection system PS. Figure 2 1-6 additional reflective elements beyond the elements shown.

[0042] Alternatively, the source collector module SO may be part of a LPP radiation system.

[0043] like Figure 1 As shown, in an embodiment, the lithographic apparatus 100 comprises an illumination system IL and a projection system PS. The illumination system IL is configured to emit a radiation beam B. The projection system PS is separated from the substrate table WT by an intervening space. The projection system PS is configured to project a pattern imparted to the radiation beam B onto the substrate W. The pattern is for EUV radiation of the radiation beam B.

[0044] The space between the projection system PS and the substrate table WT may be at least partially evacuated.The intervening space may be bounded by a solid surface at the location of the projection system PS, from which the used radiation is directed towards the substrate table WT.

[0045] In one embodiment, the lithographic apparatus 100 comprises a dynamic airlock. The dynamic airlock comprises a diaphragm assembly 80. In one embodiment, the dynamic airlock comprises a hollow portion covered by the diaphragm assembly 80 located in the intervening space. The hollow portion is located around the path of the radiation. In one embodiment, the lithographic apparatus 100 comprises a blower configured to flush the interior of the hollow portion with an airflow. The radiation travels through the diaphragm assembly and then impinges on the substrate W.

[0046] In one embodiment, the lithographic apparatus 100 includes a diaphragm assembly 80. As explained above, in one embodiment, the diaphragm assembly 80 is used for a dynamic gas lock. In this case, the diaphragm assembly 80 is used as a filter for filtering DUV radiation. Additionally or alternatively, in one embodiment, the diaphragm assembly 80 is a pellicle of a pattern forming device MA for EUV lithography. The diaphragm assembly 80 of the present invention can be used for a dynamic gas lock or for a pellicle or for another purpose, such as a spectral purity filter. In one embodiment, the diaphragm assembly 80 includes a diaphragm 40, which is also referred to as a diaphragm stack. In one embodiment, the diaphragm is configured to transmit at least 80% of the incident EUV radiation.

[0047] Conceptually, an EUV diaphragm stack consists of one or more layers of material, which are stacked in a certain order to achieve the functional requirements, thereby producing an optimal diaphragm stack in terms of performance (through lifetime), reliability and cost. The layers with specific functional requirements can be selected, for example, from the following layers: core material layer (i.e. core layer of the diaphragm or diaphragm stack), layer for thermal emission enhancement, oxidation barrier layer, corrosion barrier layer and / or process etch stop layer. It is possible that a single material layer meets multiple functional requirements (e.g. corrosion barrier and emission enhancement in the case of a Ru layer).

[0048] In one embodiment, the diaphragm assembly 80 is configured to seal the patterning device MA to protect the patterning device MA from airborne particles and other forms of contaminants. Contaminants on the surface of the patterning device MA may cause manufacturing defects on the substrate W. For example, in one embodiment, the pellicle is configured to reduce the possibility that particles may migrate into the stepping field of the patterning device MA in the lithographic apparatus 100.

[0049] If the patterning device MA is not protected, contamination may require cleaning or discarding the patterning device MA. Cleaning the patterning device MA interrupts valuable manufacturing time and discarding the patterning device MA is costly. Replacing the patterning device MA also interrupts valuable manufacturing time.

[0050] Figure 3 A portion of a diaphragm assembly 80 according to an embodiment of the present invention is schematically shown in cross-section. The diaphragm assembly 80 is used for EUV lithography. The diaphragm assembly 80 includes a diaphragm 40. The diaphragm 40 emits EUV radiation. Of course, the diaphragm 40 may not have an emissivity of 100% for EUV radiation. However, the diaphragm may have an emissivity of, for example, at least 50%. Figure 3 As shown, in one embodiment, the membrane 40 is substantially planar. In one embodiment, the plane of the membrane 40 is substantially parallel to the plane of the patterning device MA.

[0051] The diaphragm assembly 80 has a shape such as a square, a circle or a rectangle. The shape of the diaphragm assembly 80 is not particularly limited. The size of the diaphragm assembly 80 is not particularly limited. For example, in one embodiment, the diameter of the diaphragm assembly 80 is in the range of about 100 mm to about 500 mm, for example, about 200 mm.

[0052] like Figure 3 As shown, in one embodiment, the diaphragm assembly 80 includes a frame 81. The frame 81 is configured to hold the diaphragm 40. The frame 81 provides mechanical stability to the diaphragm 40. The frame 81 is configured to reduce the possibility of the diaphragm 40 deforming away from its planar shape. In one embodiment, a pre-tension is applied to the diaphragm 40 during manufacture of the diaphragm 40. The frame 81 is configured to maintain tension in the diaphragm 40 so that the diaphragm 40 does not have an undulating shape during use of the lithographic apparatus 100. In one embodiment, the frame 81 extends along the periphery of the diaphragm 40. The outer periphery of the diaphragm 40 is disposed on top of the frame 81 (according to Figure 3 of the view).

[0053] The thickness of the frame 81 is not particularly limited. For example, in one embodiment, the frame 81 has a thickness of at least 300 μm, optionally at least 400 μm. In one embodiment, the frame 81 has a thickness of at most 1,000 μm, optionally at most 800 μm. In one embodiment, the frame 81 has a width of at least 1 mm, optionally at least 2 mm, optionally at least 4 mm. In one embodiment, the frame 81 has a width of at most 10 mm, optionally at most 5 mm, optionally at most 4 mm.

[0054] like Figure 3As shown, in one embodiment, the diaphragm assembly 80 includes a frame assembly 50. The frame assembly 50 is connected to the frame 81. In one embodiment, the frame assembly 50 is initially manufactured as a separate component from the frame 81 and is subsequently connected to the frame 81. For example, the combination of the diaphragm 40 and the frame 81 can be manufactured together, and the frame assembly 50 can be manufactured separately. In a subsequent manufacturing step, the frame assembly 50 can be attached or fixed to the frame 81.

[0055] In one embodiment, the frame assembly 50 has a width of at least 2 mm, optionally at least 5 mm, optionally at least 8 mm. In one embodiment, the frame assembly 50 has a width of at most 20 mm, optionally at most 10 mm, optionally at most 8 mm.

[0056] In one embodiment, the frame assembly 50 includes a frame 51. The frame 51 is the portion of the frame assembly 50 that is connected to the border 81. In one embodiment, the frame 51 is made of the same material as the border 81. For example, in one embodiment, the border 81 and the frame 51 are both made of a material including silicon. In one embodiment, the border 81 is made of silicon. In one embodiment, the frame 51 is made of silicon. In one embodiment, the thermal expansion of the border 81 substantially matches the thermal expansion of the frame 51. In one embodiment, the frame 51 is attached to the border 81 by an adhesive. In one embodiment, the thermal expansion of the adhesive substantially matches the thermal expansion of the frame 51 and / or the border 81.

[0057] like Figure 3 As shown, the frame assembly 50 is configured to be attached to the patterning device MA. The frame assembly 50 is used to maintain the position of the diaphragm 40 relative to the patterning device MA. Although the embodiments are described with reference to the patterning device MA, the present invention is equally applicable to a diaphragm assembly 80 connected to a different component other than the patterning device MA.

[0058] In one embodiment, the frame assembly 50 is connected to the frame 81 in a direction perpendicular to the plane of the diaphragm 40. Figure 3 In Figure 3 In FIG. 4 , the plane of the diaphragm 40 extends from left to right and extends into and out of the paper. The direction perpendicular to the plane of the diaphragm 40 corresponds to Figure 3 The frame assembly 50 is directly connected to the lower part of the frame 81. The frame 81 and the frame assembly 50 are connected to the lower part of the frame 81. Figure 3 In one embodiment, the interface between the frame 81 and the frame assembly 50 is in a plane substantially parallel to the plane of the diaphragm 40.

[0059] In one embodiment, the membrane assembly 80 is configured to be removable from the patterning device MA. This allows for intermediate inspection of the patterning device MA. In one embodiment, the frame assembly 50 is configured to be repeatedly attached to and detached from the patterning device MA.

[0060] In use, the frame assembly 50 is located between the frame 81 and the patterning device MA. This arrangement differs from an arrangement in which the frame assembly is located radially outward from the frame. It is contemplated that one embodiment of the present invention achieves a reduction in the space around the membrane 40 required to hold the membrane 40 in place relative to the patterning device MA.

[0061] According to a comparative example, the diaphragm assembly has a frame assembly radially outward from the frame. The frame assembly needs to be accessed in the radial direction in order to connect the frame assembly to / detach the frame assembly from the pattern forming device. A space of about 16 mm may be required to accommodate the frame, the frame assembly, and the space for accessing the frame assembly.

[0062] In contrast, in one embodiment, the frame assembly 50 is positioned below the bezel 81, thereby reducing the radial space required to accommodate the bezel 81 and the frame assembly 50. For example, in one embodiment, the radial space required to accommodate the bezel 81, the frame assembly 50, and the space for access to the frame assembly 50 is approximately 12 mm.

[0063] It is contemplated that embodiments of the present invention achieve a reduction in the space required for mounting features in the area of ​​the patterning device MA. The mounting features are features used to mount the diaphragm assembly 80 to the patterning device MA. In one embodiment, the mounting features are disposed between the frame 81 and the patterning device MA. This Figure 3 and will be described in further detail below.

[0064] In one embodiment, the frame assembly 50 includes at least one hole 52. In one embodiment, the hole 52 is a cavity or chamber within the frame 51 of the frame assembly 50. The hole 52 is configured to receive a stud 60. The stud 60 protrudes from the patterning device MA.

[0065] Figure 3 A stud 60 is shown secured to the patterning device MA. In one embodiment, the stud 60 is glued to the patterning device MA using an adhesive. Alternatively, the stud 60 may be integrally formed with the patterning device MA. As another alternative, the stud 60 may be initially manufactured as a separate component from the patterning device MA and subsequently secured to the patterning device MA using a mechanism other than an adhesive, such as a screw.

[0066] The studs 60 and holes 52 are mounting features. In one embodiment, the studs 60 and holes 52 are disposed between the frame 81 and the patterning device MA. This is different from previously known arrangements in which the mounting features are positioned radially outward from the frame 81.

[0067] like Figure 3 As shown, in one embodiment, when viewed in a direction perpendicular to the plane of the diaphragm 40, the hole 52 at least partially overlaps the frame 81. Figure 3 As shown in FIG. 8 , when viewed in the vertical direction, the hole 52 partially overlaps the frame 81. Figure 3 , a vertical line extending through the border 81 and the hole 52 can be drawn.

[0068] In one embodiment, the frame assembly 50 includes a locking mechanism 55. The locking mechanism 55 is configured to lock the frame assembly 50 to the stud 60. In one embodiment, the locking mechanism 55 includes an elastic member 53. In one embodiment, the locking mechanism 55 includes an elastic member 53 for each hole 52. In one embodiment, the frame assembly 50 includes a plurality of holes 52, such as two, three, four or more holes 52. The elastic member 53 is provided corresponding to each hole 52.

[0069] like Figure 3 As shown, in one embodiment, the elastic member 53 comprises a spring. For example, the spring can be a coil spring or a leaf spring. In an alternative embodiment, the elastic member 53 comprises an elastic material such as rubber. In an alternative embodiment, the elastic member 53 comprises a flexure. For example, the flexure can be processed using an electrical discharge machining process.

[0070] Figures 4 to 6 Stages of use of the locking mechanism 55 are schematically illustrated. Figures 4 to 6 Shown in plan view. Figure 4 An initial state is shown, in which the frame assembly 50 is positioned over the stud 60 so that the stud 60 is received in the hole 52. The elastic member 53 is not compressed. Figure 4 As shown, the resilient member 53 extends into the hole 52. Therefore, when the stud 60 is received in the hole 52, the stud 60 can contact the resilient member 53. When the stud 60 received in the hole 52 presses against the resilient member 53 in a direction within the plane of the diaphragm 40, the resilient member 53 is configured to be compressible. For example, in Figure 4 , the stud 60 can be pressed against the elastic member 53 in the rightward direction in the figure.

[0071] like Figure 3-6As shown, in one embodiment, the locking mechanism 55 includes a locking member 54 for each hole 52. The locking member 54 is configured to be movable to a locked position in which the locking member 54 extends into the hole 52. In the locked position, the compressed elastic member 53 exerts a force on the stud 60 received in the hole 52 toward the locking member 54. This is shown in FIG. Figures 4 to 6 in the sequence.

[0072] As from Figures 4 to 5 As shown in the transition of FIG. 5 , the stud 60 and the frame assembly 50 move relative to each other so that the stud 60 presses against the elastic member 53. The stud 60 compresses the elastic member 53, as shown in FIG. Figure 5 shown.

[0073] like Figures 5 and 6 As shown in the transition of FIG. 5 , the locking member 54 moves to a locked position in which the locking member 54 extends into the hole 52. For example, as shown in FIG. Figures 4 to 6 As shown, in one embodiment, the frame assembly 50 includes at least one locking aperture 56. The locking member 54 passes through the locking aperture 56.

[0074] Figure 6 The locking member 54 is shown in the locked position. The elastic member 53 exerts a force on the stud 60 in the direction of the locking member 54. Figure 5 In the case shown, it is necessary to apply an external force on the frame assembly 50 and / or the stud 60 so that the stud 60 compresses the elastic member 53. Once the locking member 54 is in the locked position (e.g., Figure 6 As shown in FIG. 5 , there is no need to apply external force. This is because the locking member 54 holds the stud 60 and the frame assembly 50 in place relative to each other.

[0075] As described above, the studs 60 are located below the frame 81, rather than radially outside the frame 81. This may require increasing the distance (also referred to as the standoff distance) between the pattern forming device MA and the diaphragm 40. The distance between the surface of the pattern forming device MA and the diaphragm 40 substantially corresponds to the combined height of the frame assembly 50 and the frame 81. In one embodiment, the combined height of the frame assembly 50 and the frame 81 is at least 1 mm, at least 2 mm, and optionally at least 5 mm. In one embodiment, the combined height of the frame assembly 50 and the frame 81 is at most 20 mm, optionally at most 10 mm, and optionally at most 5 mm.

[0076] In one embodiment, the resilient member 53 comprises a resilient material such as stainless steel. In one embodiment, the resilient member 53 is connected to a contact pad 57 made of a different material than the resilient member 53. For example, the contact pad 57 can be made of the same material as the stud 60 and / or the locking member 54. In one embodiment, the contact pad 57 comprises titanium. In one embodiment, the locking member 54 comprises titanium. In one embodiment, the stud 60 comprises titanium. Titanium is known to provide ductile contact. However, in alternative embodiments, other materials may be used for the contact pad 57, the stud 60, and the locking member 54.

[0077] like Figures 4 to 6 As shown, in one embodiment, the cross-sectional area of ​​the hole 52 in plan view is greater than the cross-sectional area of ​​the stud 60. The hole 52 is oversized relative to the stud 60. In one embodiment, the resilient member 53 is disposed facing the end stop (not shown). When viewed in plan view, the resilient member 53 protrudes into the hole 52 (as shown in FIG. 1 ). Figure 4 52). Thus, the resilient member 53 effectively reduces the cross-sectional area of ​​the hole 52 in a plan view. The remaining cross-sectional dimension of the hole 52 is greater than the cross-sectional dimension of the stud 60. Thus, when the frame assembly 50 moves vertically on the stud 60, the stud 60 can be received in the hole 52. The frame assembly 50 is pushed laterally against the resilient member 53, causing the resilient member 53 to deflect inwardly. A locking member 54 is placed to prevent the frame assembly 50 from bending backward. In one embodiment, the locking member 54 is a pin. The locking member 54 can be inserted from the side or from the top. After the locking member 54 is inserted, the frame assembly 50 is locked to the pattern forming device MA.

[0078] In one embodiment, the frame assembly 50 includes four holes 52 evenly distributed around the frame assembly 50. In one embodiment, the frame assembly 50 has a shape similar to the frame 81, and the shape of the frame assembly 50 extends along the perimeter of the diaphragm 40. Figure 3 The resilient member 53 is shown radially inside the hole 52. However, this is not necessarily the case. The resilient member 53 may be radially outside the hole 52, or neither radially inside nor radially outside relative to the hole 52. The hole 52 is located between the resilient member 53 and the locking member 54.

[0079] In one embodiment, one resilient member 53 is radially inward of a hole 52 on one side of the diaphragm assembly 80, while another resilient member 53 is radially outward of another hole 52 on the opposite side of the diaphragm assembly 80. This allows the studs 60 at opposite sides of the patterning device MA to compress both resilient members 52 with one movement of the diaphragm assembly 80 relative to the patterning device MA. In one embodiment, the diaphragm assembly 80 is configured such that all studs 60 received in corresponding holes 52 compress corresponding resilient members 52 with one movement of the diaphragm assembly 80 relative to the patterning device MA.

[0080] like Figure 4-6 As shown, in one embodiment, the locking member 54 is provided as a loose component. In an alternative embodiment, the locking member can be formed integrally with the rest of the frame assembly 50, as long as the locking member 54 can be slid into the locked position.

[0081] In one embodiment, the diameter of the stud 60 (in plan view) is at least 1 mm, optionally at least 2 mm, and optionally at least 3 mm. In one embodiment, the diameter of the stud 60 is at most 10 mm, optionally at most 5 mm, and optionally at most 3 mm.

[0082] As described above, in one embodiment, the resilient member 53 extends into the hole 52 when not compressed. In one embodiment, the resilient member 53 extends into the hole 52 a distance of at least 0.1 mm, optionally at least 0.2 mm, and optionally at least 0.5 mm. In one embodiment, the resilient member 53 extends into the hole 52 a distance of at most 2 mm, optionally at most 1 mm, and optionally at most 0.5 mm.

[0083] As described above, the diameter of the hole 52 is greater than the diameter of the stud 60. In one embodiment, the diameter of the hole is at least 0.2 mm, optionally at least 0.5 mm, and optionally at least 1 mm greater than the diameter of the stud 60. In one embodiment, the diameter of the hole 52 is at most 5 mm, optionally at most 2 mm, and optionally at most 1 mm greater than the diameter of the stud 60. In one embodiment, the locking member 54 has a length of at least 1 mm, optionally at least 2 mm, and optionally at least 4 mm.

[0084] In one embodiment, the locking member 54 has a length of at most 10 mm, optionally at most 5 mm, and optionally at most 4 mm. In one embodiment, the locking member 54 has a width of at least 0.2 mm, optionally at least 0.5 mm, and optionally at least 1 mm. In one embodiment, the locking member 54 has a width of at most 5 mm, optionally at most 2 mm, and optionally at most 1 mm.

[0085] It is contemplated that embodiments of the present invention enable a reduction in tooling steps required to attach / detach the component assembly 80 to / from the patterning device MA.

[0086] Figure 7 A diaphragm 40 according to one embodiment of the present invention is schematically depicted in cross section. Figure 7 As shown, the diaphragm 40 comprises a stack. The stack comprises a plurality of layers.

[0087] In one embodiment, the stack includes at least one silicon layer 41. The silicon layer 41 includes a form of silicon. In one embodiment, the stack includes at least one silicon compound layer 43. The silicon compound layer 43 is composed of a compound of silicon and another element selected from the group consisting of boron, phosphorus, bromine and sulfur. However, other elements may also be used. In particular, in one embodiment, the element combined with silicon to form the silicon compound layer 43 is any element that can be used as a doping material for doping the silicon layer 41. For convenience only, the embodiment will be described using boron as the element combined with silicon. The embodiment is not limited to the boron element.

[0088] In one embodiment, silicon compound layer 43 comprises silicon boride. Silicon boride has the chemical formula SiBx, where x can be 3, 4, 6, 14, 15, 40, etc. Silicon boride has metallic properties. In particular, silicon compound layer 43 has metallic properties, which increases the emissivity of EUV radiation of diaphragm 40. A diaphragm made of silicon layer 41 alone will have a low emissivity, perhaps on the order of 3%. If a compound or metal with metallic properties is added to diaphragm 40, the emissivity increases significantly.

[0089] Metals are known to limit the practical thickness of the diaphragm due to EUV absorption. By providing a silicon diaphragm layer 43, embodiments of the present invention are expected to enable an increase in the possible thickness of the diaphragm 40 with sufficient emissivity for use in the lithographic apparatus 100.

[0090] like Figure 7 As shown, in one embodiment, the silicon compound layer 43 is formed as an intermediate layer between the silicon layer 41 and the non-metallic layer 42, and the non-metallic layer 42 includes an element that combines with silicon to form the silicon compound layer 43. For example, in one embodiment, the non-metallic layer 42 includes boron. In one embodiment, the boron is provided in the form of boron carbide. However, alternative forms of boron can be used.

[0091] In one embodiment, silicon layer 41 is initially disposed adjacent to non-metal layer 42. Boron in non-metal layer 42 locally dopes silicon in silicon layer 41. Boron dopes silicon to the extent that silicon boronide is produced to form silicon compound layer 43. Boron doping of silicon causes more boron atoms to be present in the doped silicon than silicon atoms, i.e., silicon boronide is formed.

[0092] In one embodiment, the silicon layer 41 and the non-metal layer 42 are arranged as multiple layers. Locally, the silicon boride can strengthen the diaphragm 40 (through lamination effect and radiation hardening of boron in silicon), so that the diaphragm 40 can withstand higher temperatures.

[0093] like Figure 7 As shown, in one embodiment, the stack includes a plurality of silicon layers 41 , a plurality of non-metal layers 42 , and a silicon compound layer 43 between each pair of the silicon layer 41 and the non-metal layer 42 .

[0094] like Figure 7 As shown, in one embodiment, the stack includes the following order of layers: non-metallic layer 42, silicon compound layer 43, silicon layer 41, silicon compound layer 43, non-metallic layer 42, silicon compound layer 43, silicon layer 41, silicon compound layer 43, non-metallic layer 42, silicon compound layer 43, silicon layer 41, silicon compound layer 43, non-metallic layer 42, silicon compound layer 43, silicon layer 41, silicon compound layer 43 and non-metallic layer 42. This is a multi-layer stack. In one embodiment, the stack may include a non-metallic layer 42, followed by a set of four layers including a silicon compound layer 43, a silicon layer 41, a silicon compound layer 43 and a non-metallic layer 42.

[0095] In one embodiment, each non-metal layer 42 has a thickness of at least 0.5 nm, optionally at least 1 nm, and optionally at least 2 nm. In one embodiment, each non-metal layer 42 has a thickness of at most 10 nm, optionally at most 5 nm, and optionally at most 2 nm.

[0096] In one embodiment, each silicon compound layer 43 has a thickness of at least 0.5 nm, optionally at least 1 nm, and optionally at least 2 nm. In one embodiment, each silicon compound layer 43 has a thickness of at most 10 nm, optionally at most 5 nm, and optionally at most 2 nm.

[0097] In one embodiment, each silicon layer 41 has a thickness of at least 2 nm, optionally at least 5 nm, and optionally at least 8 nm. In one embodiment, each silicon layer 41 has a thickness of at most 20 nm, optionally at most 10 nm, and optionally at most 8 nm.

[0098] Figure 7 The embodiment shown in has a silicon layer 41 with a thickness of 8 nm, a non-metallic layer 42 with a thickness of 2 nm and a silicon compound layer 43 with a thickness of 2 nm, which is expected to achieve an emissivity of approximately 90% for EUV radiation.

[0099] Figure 8An alternative embodiment is shown in which the layer stack comprises the following order of layers: non-metallic layer 42 , silicon compound layer 43 , silicon layer 41 , silicon compound layer 43 and non-metallic layer 42 .

[0100] like Figure 8 As shown, in one embodiment, the diaphragm 40 includes only one silicon layer 41. In one embodiment, the silicon layer 41 has a thickness of at least 10 nm, optionally at least 20 nm, and optionally at least 38 nm. In one embodiment, the single silicon layer 41 has a thickness of at most 100 nm, optionally at most 50 nm, and optionally at most 38 nm. Figure 8 The embodiment shown in has a silicon layer 41 with a thickness of 38 nm, a non-metallic layer 42 with a thickness of 4 nm and a silicon compound layer 43 with a thickness of 2 nm, which is expected to achieve an emissivity of approximately 90% for EUV radiation.

[0101] In one embodiment, the total combined thickness of the silicon compound layers 43 in the stack is at most about 20 nm. Metals and compounds with metallic properties improve the emissivity of the diaphragm 40, provided that the combined thickness is not too thick. For too thick metal layers or compound layers with metallic properties, the emissivity may be reduced.

[0102] Fig. 9 An alternative embodiment of the diaphragm 40 is schematically shown. Fig. 9 As shown, in one embodiment, the stack includes at least one silicon layer 41, at least one cap layer 46 and at least one anti-migration layer 47. In one embodiment, the cap layer 46 includes ruthenium. The cap layer 46 is disposed on the outer surface of the diaphragm 40. The anti-migration layer 47 includes at least one of molybdenum and titanium. The anti-migration layer 47 is adjacent to each cap layer 46.

[0103] The cap layer 46 including ruthenium improves the emissivity of the diaphragm 40. The cap layer 46 reduces the possibility of oxidation of the diaphragm 40. The cap layer 46 is configured to protect the diaphragm 40 from hydrogen gas.

[0104] During use of the lithographic apparatus 100, the diaphragm 40 may heat up due to absorption of radiation. When the cap layer 46 heats up, the material of the cap layer 46 (e.g., ruthenium) may migrate. Migration is the transport of material caused by the gradual movement of ions in the cap layer 46. When the material begins to migrate, the material may form islands in the cap layer 46. When the material begins to migrate, the effect of the cap layer 46 in reducing oxidation, protecting from hydrogen, and improving emissivity is reduced. Therefore, during use of the lithographic apparatus 100, the diaphragm 40 may begin to oxidize and the emissivity may decrease.

[0105] By providing the anti-migration layer 47, migration of the cap layer 46 is reduced. Molybdenum and titanium are metals with relatively high melting temperatures and good emissivity of EUV radiation. When heated, titanium and molybdenum do not migrate as much as ruthenium. Titanium and molybdenum have good metal-to-metal contact with ruthenium. By providing the anti-migration layer 47 adjacent to the cap layer 46, migration of the cap layer 46 is reduced. As a result, even when the cap layer 46 is heated during use of the lithographic apparatus 100, the good properties of the cap layer 46 are maintained at higher temperatures.

[0106] like Fig. 9 As shown, in one embodiment, the stack includes layers in the following order: a cap layer 46 including ruthenium located at an outer surface of the diaphragm 40, an anti-migration layer 47 including at least one of molybdenum and titanium, a silicon layer 41, an anti-migration layer 47 including at least one of molybdenum and titanium, and a cap layer 46 including ruthenium at another outer surface of the diaphragm 40. In one embodiment, the cap layer 46 including ruthenium is provided at both outer surfaces of the diaphragm 40.

[0107] Fig.10 An alternative embodiment of a membrane is shown in which the use of an anti-migration layer 47 is combined with the idea of ​​using a silicon compound layer 43 .

[0108] like Fig.10 As shown, in one embodiment, the stack includes layers in the following order: a cap layer 46 including ruthenium located at the outer surface of the diaphragm 40, an anti-migration layer 47 including at least one of molybdenum and titanium, a silicon layer 41, a silicon compound layer 43 and a non-metallic layer 42.

[0109] During the manufacture of the diaphragm assembly 80, the boron carbide layer can chemically protect the silicon layer 41 from the etching process. In one embodiment, the diaphragm 40 includes a periodic structure. In one embodiment, the period is not set equal to 6.6nm or 6.7nm. If the period is at or close to 6.7nm, the diaphragm can act as a mirror for EUV radiation.

[0110] Silicon can be crystallized in a diamond cubic crystal structure. In one embodiment, the frame 81 includes cubic crystals of silicon. In one embodiment, the frame 81 has <100> Crystallographic direction.

[0111] In one embodiment, the silicon layer 41 is formed of polycrystalline silicon or nanocrystalline silicon. Polycrystalline silicon or nanocrystalline silicon has brittleness. Therefore, when the diaphragm assembly 80 is broken, the diaphragm 40 including the silicon layer 41 formed of polycrystalline silicon or nanocrystalline silicon may be broken into many particles. It is expected that the embodiments of the present invention achieve improvements in the mechanical properties of the diaphragm assembly 80.

[0112] Polycrystalline silicon and nanocrystalline silicon each have high transmittance for EUV radiation.Polycrystalline silicon and nanocrystalline silicon each have good mechanical strength.

[0113] However, the diaphragm of the silicon layer 41 does not have to be formed of polycrystalline silicon or nanocrystalline silicon. For example, in an alternative embodiment, the silicon layer 41 is formed of a polycrystalline diaphragm or silicon nitride.

[0114] In another alternative embodiment, silicon layer 41 is formed of single crystal silicon. In such an embodiment, the single crystal silicon diaphragm can be formed by silicon on insulator (SOI) technology. The starting material for this product is a so-called SOI substrate. An SOI substrate is a substrate comprising a silicon carrier substrate with a thin single crystal silicon layer on top of an embedded isolated SiO2 layer. In one embodiment, the thickness of the single crystal silicon layer can be in the range of about 5nm to about 5μm. In one embodiment, silicon layer 41 exists on the SOI substrate before the SOI substrate is used in the manufacturing method.

[0115] In one embodiment, the silicon layer 41 includes silicon in one of its various allotropic forms, such as amorphous silicon, monocrystalline silicon, polycrystalline silicon, or nanocrystalline silicon. Nanocrystalline silicon refers to a polycrystalline silicon matrix containing a certain amorphous silicon component. In one embodiment, polycrystalline silicon or nanocrystalline silicon is formed by crystallizing the amorphous silicon in the silicon layer 41. For example, in one embodiment, the silicon layer 41 is added to the stack as an amorphous silicon layer. When a certain temperature is exceeded, the amorphous silicon layer crystallizes into a polycrystalline silicon layer or a nanocrystalline silicon layer. For example, the silicon layer 41 as an amorphous silicon layer is transformed into the silicon layer 41 as a polycrystalline silicon layer or a nanocrystalline silicon layer.

[0116] In one embodiment, the amorphous silicon layer is doped in situ during its growth. In one embodiment, the amorphous silicon layer is doped after its growth. By adding p-type or n-type dopants, the silicon conductivity increases, which has a positive impact on the thermodynamic properties caused by the power of the EUV source.

[0117] In one embodiment, the membrane 40 is thin enough so that its transmittance to EUV radiation is high enough, for example greater than 50%. In one embodiment, the thickness of the membrane 40 is at most about 200 nm, and optionally at most about 150 nm. A 150 nm Si membrane will transmit about 77% of the incident EUV radiation. In one embodiment, the thickness of the membrane 40 is at most about 100 nm. A 100 nm Si membrane will transmit about 84% of the incident EUV radiation. A 60 nm Si membrane will transmit about 90% of the incident EUV radiation.

[0118] In one embodiment, membrane 40 is thick enough to be mechanically stable when membrane assembly 80 is fixed to patterning device MA of lithographic apparatus 100 and during use of lithographic apparatus 100. In one embodiment, the thickness of membrane 40 is at least about 10 nm, optionally at least about 20 nm, and optionally at least about 35 nm. In one embodiment, the thickness of membrane 40 is about 55 nm.

[0119] Figures 11 to 13 Different embodiments of a membrane 40 according to the invention are schematically shown in cross section. When designing the membrane 40 there is a trade-off between the thickness of the membrane 40, its stability and robustness.

[0120] like Fig.11 As shown, in one embodiment, the diaphragm 40 includes a silicon layer 41 sandwiched between two cap layers 46. In one embodiment, the silicon layer 41 includes polysilicon. In one embodiment, the same (cap) material is used for both cap layers 46. However, this is not necessarily the case. In alternative embodiments, the material used for one of the cap layers 46 is different from the material used for the other cap layer 46.

[0121] In one embodiment, the cap layer 46 is located at the outer surface of the diaphragm 40. Thus, in one embodiment, the stack includes the following order of layers: the cap layer 46 located at the outer surface of the diaphragm 40, the silicon layer 41, and the cap layer 36 including a transition metal silicide.

[0122] In one embodiment, the cap layer 46 includes a transition metal silicide. The specific transition metal is not particularly limited, but can be, for example, Zr, Y, Mo, Cr, Hf, Ir, Mn, Nb, Os, Pd, Pt, Re, Rh, Ru, Ta, Ti, V or W.

[0123] Transition metal silicides transmit a particularly high proportion of EUV radiation. It is desirable that the transmission of the membrane 40 to EUV radiation is as high as possible. In one embodiment, the materials used for the stack are selected such that for EUV radiation with a wavelength of 13.5 nm, the extinction coefficient k is less than 0.0175.

[0124] The extinction coefficient k is related to EUV transmittance. When EUV radiation passes through a medium, some part of the EUV radiation is attenuated. By defining the complex refractive index The attenuation may conveniently be taken into account.

[0125] Here, the real part n of the complex refractive index is the refractive index and represents the phase velocity. The extinction coefficient k is the imaginary part of the complex refractive index. The extinction coefficient k represents the attenuation amount when an electromagnetic wave propagates through a material.

[0126] In the above description, the value of the extinction coefficient k is given for radiation with a wavelength of 13.5 nm. Using this value and the given material thickness, we can calculate the EUV transmittance / absorbance of the layer within the membrane 40. For a material layer with a specific value of extinction coefficient k=0.0175, a layer of 4 nm thickness absorbs 6% of the EUV radiation (i.e., 6% EUV transmission loss).

[0127] Capping layers 46 need not include a transition metal silicide. In alternative embodiments, one or both of capping layers 46 include a transition metal boride, a transition metal carbide, a transition metal nitride, a transition metal oxide, or a transition metal in pure form.

[0128] Table 1 shows a selection of suitable capping materials (in descending order of EUV transmission value) with respect to melting temperature, coefficient of thermal expansion (CTE), resistivity of the diaphragm, EUV radiation transmittance, capping thickness d in nm corresponding to a loss of 6% EUV transmission, real part n of the complex refractive index for radiation with a wavelength of 13.5 nm and values ​​of the extinction coefficient k for radiation with a wavelength of 13.5 nm.

[0129] Examples of suitable cap layer materials (in descending order of their EUV transmittance values ​​from 99.8% to 94.6%): Si, Y, YSi2, LaSi2, ZrSi2, SiB4, B, Zr, YB6, NbSi3, MoSi2, YC2, SiC, ZrB2, La, CeSi2, B4C, Nb, CeB6, LaB6, NbB2, ZrC, Ce, Mo, CeC2, YN, LaC2, MoB, LaN, C, Mo2C, NbC, TiSi2, Ru2Si3, Si3N6, BN, ZrN, VSi2, CeN, RuB2, NbN, SiO2, Y2O3, MoN, TiB2, La2O3, Nb2O5, WSi2, Ti, ZrO2, B2O3, MoO3, TiC, RuC, SiCr, Ru, WB2, VB2, TaS i2, CeO2, TiN, RuN, RuO2, TiO3, VC, V, TaB2, VN, WC, CrB, TiW, CrN, W, HfO2, Cr3C2, WN, TaC, Ta2O5, TaN, Cr, Al2O3, Ta and Pt.

[0130] Preferred capping materials that may provide an optimal combination of melting temperature, resistivity, EUV transmittance, refractive index n and extinction coefficient k are, for example, CeB6, LaB6, NbSi3, Zr, YSi2, CeSi2, Y, CeC2, LaC2, LaSi2, ZrB2, Nb, LaN, YC2, ZrSi2, SiB4, B, YB6, MoSi2, YC2, SiC, La, B4C, Ce, CeN, Ru2Si3, YN, ZrC, NbB2, NbC, Mo2C, MoB and Mo.

[0131] Table 1: List of cover materials

[0132]

[0133]

[0134] Transition metal silicides transmit a higher proportion of EUV radiation than transition metal borides, transition metal carbides, transition metal nitrides, transition metal oxides or transition metals in pure form.

[0135] With regard to EUV transmission properties, possible materials for the diaphragm 40 have the following ranking, where the materials that transmit the highest proportion of EUV radiation are given first: transition metal silicides, transition metal borides, pure transition metals, transition metal carbides, transition metal nitrides, and transition metal oxides. Depending on the transition metal, pure transition metals may be preferred over transition metal borides. Depending on the transition metal, transition metal carbides may be preferred over pure transition metals. An example of a transition metal carbide is molybdenum carbide.

[0136] In addition, transition metal silicides have particularly desirable EUV reflection properties. It is desirable that the EUV reflection (i.e., the proportion of EUV radiation reflected at the surface of the diaphragm 40) is as low as possible. Transition metal silicides reflect a lower proportion of EUV radiation than transition metal oxides, transition metal borides, transition metal carbides, transition metal nitrides, or pure forms of transition metals.

[0137] In one embodiment, the materials of the stack of layers of the membrane 40 are selected such that for EUV radiation of wavelength 13.5 nm, the refractive index of the stack is greater than 0.95. A refractive index close to 1 limits EUV reflection of the interfaces of the membrane 40 .

[0138] With respect to EUV reflection properties, possible materials for the membrane 40 have the following ranking, where the material reflecting the lowest proportion of EUV radiation is given first: transition metal silicide, transition metal oxide, pure transition metal, transition metal boride, transition metal carbide and transition metal nitride. However, there are no significant differences with respect to EUV reflection properties between transition metal oxide, pure transition metal, transition metal boride and transition metal carbide.

[0139] It is desirable that the resistivity of the diaphragm 40 is low. In particular, it is desirable that the resistivity of the cap layer 46 is low. This is because the conductive coating can increase the resistivity of the diaphragm 40. The resistivity of the transition metal silicide is lower than that of the transition metal carbide, the nitride of the transition metal, or the transition metal oxide.

[0140] In one embodiment, the material of the cap layer 46 is selected such that the resistivity of the cap layer 46 is less than 10 -3 Ω·m.

[0141] With respect to resistivity, possible materials for the diaphragm 40 have the following ranking, with the material having the lowest resistivity given first: pure transition metals, transition metal borides, transition metal silicides, transition metal carbides, transition metal nitrides, and transition metal oxides.

[0142] During use of the diaphragm 40, the diaphragm 40 may reach operating temperatures up to about 600°C. Therefore, it is desirable that the materials in the stack used for the diaphragm 40 have high melting points. In one embodiment, the materials of the stack are selected such that their melting temperatures are above 1200°C.

[0143] With respect to melting points, possible materials for the diaphragm 40 have the following ranking, with the material with the highest melting point given first: transition metal carbides, transition metal borides, transition metal nitrides, pure transition metals, transition metal oxides, and transition metal silicides. Depending on the transition metal, transition metal borides may have a higher melting point than transition metal carbides. Depending on the transition metal, transition metal oxides may have a higher melting point than pure transition metals.

[0144] In one embodiment, the materials of the layers other than the silicon layer 41 are selected so that their thermal expansion coefficients are close to the thermal expansion coefficient of the silicon layer 41. The thermal expansion coefficient of the silicon layer 41 may be about 2.6×10 -6 m / m·K. Matching the thermal expansion coefficient to the thermal expansion of the silicon layer 41 at the core of the diaphragm 40 reduces the likelihood of thermodynamic failure of the diaphragm 40. In one embodiment, the materials of the stack are selected so that their thermal expansion coefficients are in the range from about 2×10 -6 m / m·K to about 6x10 -6 m / m·K.

[0145] With respect to the coefficient of thermal expansion, the ranking of possible materials for the diaphragm 40 depends entirely on the specific compound.

[0146] like Fig.12 As shown, in one embodiment, a transition metal layer 48 is disposed between the silicon layer 41 and one of the cap layers 46. The transition metal layer 48 includes a transition metal. For example, the transition metal may be Zr, Y, Mo, Cr, Hf, Ir, Mn, Nb, Os, Pd, Pt, Re, Rh, Ru, Ta, Ti, V, or W. In one embodiment, the transition metal is provided in a pure form in the transition metal layer 48 (i.e., not as a transition metal silicide, transition metal boride, transition metal carbide, transition metal nitride, or transition metal oxide). Therefore, in one embodiment, the stack of the diaphragm 40 includes, in sequence, the cap layer 46, the transition metal layer 48, the silicon layer, and the cap layer 46.

[0147] In one embodiment, cap layer 46 includes a boride, a carbide (e.g., molybdenum carbide), a transition metal nitride, or a transition metal oxide. The transition metal in transition metal layer 48 may be the same as transition metal cap layer 46. In an alternative embodiment, the transition metal of transition metal layer 48 is different from the transition metal used in cap layer 46.

[0148] like Fig.13 As shown, in one embodiment, a transition metal layer 48 is disposed on either side of the silicon layer 41. The transition metal layer 48 is disposed between the silicon layer 41 and each cap layer 46. Therefore, in one embodiment, the stack of the diaphragm 40 includes the cap layer 46, the transition metal layer 48, the silicon layer, the transition metal layer 48, and the cap layer 46 in sequence.

[0149] When selecting a material for membrane 40, there is a trade-off between the properties described above (ie, EUV transmittance, EUV reflectivity, melting point, coefficient of thermal expansion, and resistivity).

[0150] The ranking of possible stacks of diaphragms 40 based on cap layer 46 using the criteria specified above can be summarized in Table 2, where 1 represents the best ranking, 2 represents the next best ranking, etc. Where different stacks are given the same ranking (e.g., there are three different stacks given a ranking of 2), these stacks are considered equally good. In the table, M represents a transition metal, and pSi (core) represents polysilicon as the silicon layer 41 at the core of the diaphragm 40. The symbol " / " indicates where one layer ends and another begins.

[0151] In one embodiment, the boride is non-conductive (e.g., B). In one embodiment, the carbide is non-conductive (e.g., B4C or SiC). In one embodiment, the nitride is non-conductive (e.g., SiN). Any of the capping materials listed above may be suitable for the combinations shown in Table 2. Examples of such diaphragm stacks that are thermally, mechanically, and chemically resistant (e.g., EUV radiation and H2 exposure) at temperatures up to 450°C are, for example, ZrO2 / SiN / pSi / SiN / Mo / Ru and B / (SiN) / pSi / (SiN) / Mo / B. For example, in a stack comprising B / SiN / pSi / SiN / Zr / B, the capping layer combination Zr and B reduces the sensitivity of the diaphragm to EUV reflection (EUVR) to less than 0.04% and allows an EUV transmittance of 87-88%. In the diaphragm stack B / pSi / B / Zr / B stack: B is a capping layer, but also acts as a diffusion barrier; and Zr is an emitter layer.

[0152] Table 2: Examples of Preferred Diaphragm Stack Architectures

[0153] 1 M-silicide / pSi(core) / M-silicide 2 M-boride / pSi(core) / M-boride M-boride / M / pSi(core) / M-boride M-boride / M / pSi(core)M / / M-boride 3 M-carbide / pSi(core) / M-carbide M-carbide / M / pSi(core) / M-carbide M-Carbide / M / pSi(core)M / / M-Carbide 4 M-nitride / pSi(core) / M-nitride M-nitride / M / pSi(core) / M-nitride M-nitride / M / pSi(core) / M / M-nitride 5 M-oxide / pSi(core) / M-oxide M-oxide / M / pSi(core) / M / M-oxide

[0154] In one embodiment, the stack of diaphragm 40 includes a diffusion barrier layer. The thickness of the diffusion barrier layer is preferably less than 1 nm to minimize EUV loss. The diffusion barrier layer is located between the transition metal layer 48 and the silicon layer 41 or the silicon compound layer 43. The diffusion barrier layer is configured to reduce mixing and / or reaction between the transition metal of the transition metal layer 48 and the silicon layer 41 or the silicon compound layer 43. For example, in one embodiment, the diffusion barrier layer is configured to reduce or prevent silicidation between the transition metal and the underlying silicon core material. Mixing or reaction between the transition metal and silicon may undesirably change the properties of the diaphragm 40. For example, the emissivity of the diaphragm 40 may be undesirably reduced and / or there may be changes in the physical stress of the diaphragm 40.

[0155] In one embodiment, the diffusion barrier layer includes a material selected from the group consisting of B, B4C, C, Cr, Mg, Mo, Re, Ta, Ti, V, W and nitrides of any one of B, B4C, C, Cr, Mg, Mo, Re, Ta, Ti, V and W.

[0156] In one embodiment, the diaphragm assembly 80 is applied as a diaphragm or part of a dynamic gas lock. Alternatively, the diaphragm assembly 80 can be applied to other filtering fields such as illumination, or to a beam splitter. In one embodiment, the dynamic gas lock is configured to block debris within the lithographic apparatus 100. In one embodiment, the dynamic gas lock is located between the projection system PS and the substrate W. The dynamic gas lock reduces the possibility of particles from the substrate W or particles from the vicinity of the substrate W reaching optical elements in or around the projection system PS. Similarly, the dynamic gas lock can protect the illumination system IL. In an alternative embodiment, the dynamic gas lock is located at the virtual source point IF. For example, the dynamic gas lock can be located between the source collector module SO and the illumination system IL.

[0157] Although the lithography equipment is described in detail herein for use in manufacturing ICs, it should be understood that the lithography equipment described herein may have other applications, such as manufacturing integrated optical systems, guidance and detection patterns of magnetic domain memories, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads, etc.

[0158] The substrates referred to herein may be processed before or after exposure, such as in a track (a tool that typically applies a layer of resist to a substrate and develops the exposed resist), a metrology tool, and / or an inspection tool. Where applicable, the disclosure herein may be applied to such and other substrate processing tools. In addition, the substrates may be processed more than once, such as to produce a multi-layer IC, so that the term "substrate" as used herein may also refer to a substrate that already includes multiple processed layers.

[0159] Although specific embodiments of the present invention have been described above, it should be appreciated that the present invention may be implemented in a manner other than that described above. For example, various photoresists may be replaced by non-photoresists that perform the same function.

[0160] The above description is intended to be illustrative rather than limiting. Accordingly, those skilled in the art will appreciate that modifications may be made to the described invention without departing from the scope of the claims set forth hereinafter.

Claims

1. A membrane for EUV lithography, the membrane having a thickness of no more than 200 nm and comprising a stack of layers, the stack comprising: at least one silicon layer; at least one capping layer comprising ruthenium at an outer surface of the diaphragm; and at least one anti-migration layer comprising at least one of molybdenum and titanium adjacent to the or each cap layer, The diaphragm is held only by a frame and extends across the frame, and the frame extends along the periphery of the diaphragm.

2. The membrane of claim 1, wherein the silicon layer comprises silicon in one of its various allotropic forms, including amorphous silicon, single crystal silicon, polycrystalline silicon, or nanocrystalline silicon.

3. The diaphragm according to claim 1 or 2, wherein the cap layer comprising ruthenium is provided at both outer surfaces of the diaphragm.

4. The membrane according to any one of claims 1 to 3, wherein the membrane comprises a stack comprising a plurality of layers.

5. The membrane of claim 4, wherein the material of the stack of layers of the membrane is selected such that for EUV radiation having a wavelength of 13.5 nm, the refractive index of the stack is greater than 0.

95.

6. The diaphragm according to claim 4, wherein the material of the cap layer is selected so that the resistivity of the cap layer is less than 10 -3 Ω•m.

7. The membrane according to claim 4, wherein the materials of the stack are selected such that their melting temperature is above 1200°C.

8. The diaphragm according to claim 4, wherein the materials of the stack are selected so that their coefficient of thermal expansion is in the range from 2×10 -6 m / m•K to 6×10 -6 m / m•K range.

9. The membrane of claim 4, wherein the layer stack comprises at least one silicon compound layer.

10. The diaphragm according to claim 4, wherein The stack includes one of the following diaphragm stack architectures: M-silicide / pSi(core) / M-silicide, M-boride / pSi(core) / M-boride, M-boride / M / pSi(core) / M-boride, M-boride / M / pSi(core)M / / M-boride, M-carbide / pSi(core) / M-carbide, M-carbide / M / pSi(core) / M-carbide, M-carbide / M / pSi(core)M / / M-carbide, M-nitride / pSi(core) / M-nitride, M-nitride / M / pSi(core) / M-nitride, M-nitride / M / pSi(core) / M / M-nitride, M-oxide / pSi(core) / M-oxide, M-oxide / M / pSi(core) / M / M-oxide, wherein M is a transition metal selected from the group consisting of Zr, Y, Mo, Cr, Hf, Ir, Mn, Nb, Os, Pd, Pt, Re, Rh, Ru, Ta, Ti, V, and W.

11. The membrane of claim 4, wherein the stack comprises a Ru cap layer, a Mo transition metal layer, a silicon layer, and another cap layer.

12. A diaphragm according to claim 11, wherein the other cap layer comprises a material selected from the group consisting of transition metal silicides, transition metal borides, transition metal carbides, transition metal nitrides and transition metal oxides; and / or at least one transition metal layer between the cap layer and the silicon layer or silicon compound layer, the transition metal layer comprising a transition metal selected from the group consisting of Zr, Y, Mo, Cr, Hf, Ir, Mn, Nb, Os, Pd, Pt, Re, Rh, Ru, Ta, Ti, V and W.

13. A diaphragm according to claim 4, wherein the stack comprises layers in the following order: a capping layer comprising ruthenium located at the outer surface of the diaphragm, an anti-migration layer comprising at least one of molybdenum and titanium, a silicon layer, an anti-migration layer comprising at least one of molybdenum and titanium, and a capping layer comprising ruthenium at another outer surface of the diaphragm.

14. A diaphragm assembly for EUV lithography, comprising: border, and A diaphragm having a thickness of no more than 200 nm and comprising a stack of layers comprising: at least one silicon layer; at least one capping layer comprising ruthenium located at an outer surface of the diaphragm; and at least one anti-migration layer comprising at least one of molybdenum and titanium adjacent to the or each cap layer, The diaphragm is held only by the frame and extends across the frame, and the frame is configured to extend along the periphery of the diaphragm.

15. The diaphragm assembly of claim 14, comprising a frame connected to the frame.

16. The diaphragm assembly of claim 15, wherein the frame is made of the same material as the border.

17. The diaphragm assembly of claim 15 or 16, wherein thermal expansion of the border substantially matches thermal expansion of the frame.

18. The diaphragm assembly according to any one of claims 15 to 17, wherein the frame and / or the border are made of silicon.

19. A patterning device assembly for EUV lithography, comprising the membrane according to any one of claims 1 to 13 or the membrane assembly according to any one of claims 14 to 18.

20. A dynamic airlock assembly for EUV lithography, comprising the diaphragm according to any one of claims 1 to 13 or the diaphragm assembly according to any one of claims 14 to 18.

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