Lithography system and method

Abstract

A system for fixing particles to a pellicle membrane for subsequent use in a lithographic apparatus includes a particle fixing device configured to fix the particles to the pellicle membrane. The particle fixing device is configured to guide an electron beam or a radiation beam so that the electron beam or the radiation beam passes through the pellicle membrane before being incident on the particles.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to EP Application No. 18197443.7 filed on September 28, 2018, and priority to EP Application No. 18199853.5 filed on October 11, 2018, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to a system and method for securing particles to a pellicle membrane so that when used in a lithographic apparatus, the particles do not detach from the pellicle membrane and therefore fail to reach a reticle of the lithographic apparatus. Background Art

[0004] A lithographic apparatus is a machine configured to apply a desired pattern onto a substrate. A lithographic apparatus may be used, for example, in the manufacture of integrated circuits (ICs). A lithographic apparatus may, for example, project a pattern at a patterning device (e.g., a reticle or mask) onto a layer of radiation-sensitive material (resist) provided on a substrate.

[0005] In order to project a pattern onto a substrate, a lithographic apparatus may use electromagnetic radiation. The wavelength of the radiation determines the minimum size of a feature that can be formed on a substrate. Typical wavelengths currently in use are 365nm, 248nm, 193nm, and 13.5nm. Compared to a lithographic apparatus using radiation having a wavelength of, for example, 193nm, a lithographic apparatus using extreme ultraviolet (EUV) radiation having a wavelength in the range of 4nm to 20nm (e.g., 6.7nm or 13.5nm) can be used to form smaller features on a substrate.

[0006] Some lithography equipment (e.g., EUV and DUV lithography equipment) include a pellicle membrane attached to the mask. The pellicle membrane is a thin (e.g., less than about 70 nm thick) transmissive film that is spaced a few millimeters (e.g., about 5 mm) from the pattern of the mask. Particles received on the pellicle membrane are in the far field relative to the pattern of the mask, and therefore have no significant effect on the quality of the image projected onto the substrate by the lithography equipment. If the pellicle membrane is not present, the particles will be on the pattern of the mask and will confuse a portion of the pattern, thereby preventing the pattern from being correctly projected onto the substrate. Therefore, the pellicle membrane plays an important role in preventing particles from adversely affecting the projection of the pattern by the lithography equipment onto the substrate.

[0007] Before the pellicle is attached to a reticle for use in a lithographic apparatus, the pellicle membrane may become dirty. That is, particles may be incident on the pellicle membrane before the pellicle membrane is used in a lithographic apparatus. Activities including transporting the pellicle membrane, packaging the pellicle membrane, and mounting the pellicle membrane to a reticle may cause particles to be incident on the pellicle membrane. It has been found that some particles present on the pellicle membrane detach from the pellicle membrane and travel to the reticle during lithographic exposure and thereby adversely affect the pattern projected onto the substrate.

[0008] Currently, pellicles that are deemed too dirty for use are discarded. Known methods of dealing with the problem of dirty pellicles involve cleaning the pellicles, for example using vibration, plasma, wet cleaning, etc. However, known methods risk fracturing the pellicles because the pellicles are very thin films and are easily damaged. Some known methods of cleaning dirty pellicle membranes involve applying heat during cleaning in an attempt to avoid introducing cracks into the pellicle membrane. However, applying heat may also contribute to weakening of the pellicle, thereby reducing the operational life of the pellicle membrane.

[0009] For example, it would be desirable to provide methods that prevent or mitigate one or more of the problems of the prior art, whether identified herein or elsewhere. Summary of the invention

[0010] According to a first aspect of the present invention, there is provided a system for fixing particles to a pellicle membrane for subsequent use in a lithographic apparatus, the system comprising a particle fixing device configured to fix particles to the pellicle membrane.

[0011] Particles may be incident on the pellicle membrane before the pellicle membrane is used in a lithographic apparatus. During a lithographic exposure, some of the particles on the pellicle membrane may travel from the pellicle membrane to the mask. These particles may then be imaged onto the substrate during the lithographic exposure and thereby adversely affect the quality of the lithographic exposure. The system for securing particles to the pellicle membrane advantageously prevents particles from traveling to the mask and thereby prevents particles from adversely affecting the lithographic exposure.

[0012] The particle fixing device may be configured to irremovably fix the particles to the diaphragm membrane.The particles may be fixed to the diaphragm membrane for the entire duration of the operating life of the diaphragm membrane.

[0013] The particle fixing device can be configured to fix the particles to the reticle-facing surface of the pellicle membrane.

[0014] The particle securing device may be configured to provide a material to the pellicle membrane for securing the particles to the pellicle membrane.

[0015] The material provided to the pellicle membrane by the particle immobilization means may have a size on the pellicle membrane in the plane of the pellicle membrane of less than about 10 μm. The material provided to the pellicle membrane by the particle immobilization means may have a size on the pellicle membrane in the plane of the pellicle membrane of about 10 μm or less.

[0016] The material provided to the pellicle membrane by the particle immobilization means may have a thickness on the pellicle membrane of less than about 100 nm. The material provided to the pellicle membrane by the particle immobilization means may have a thickness on the pellicle membrane of about 100 nm or less.

[0017] If the material provided to the pellicle membrane is too thick and / or has too large a size in the plane of the pellicle membrane (e.g., a length, diameter, major axis, etc. that depends on the shape of the deposited material), there is a risk that the material itself will be at least partially imaged onto the substrate during the lithographic exposure, thereby adversely affecting the lithographic exposure. By limiting the size and / or thickness of the material on the pellicle membrane, the material and particles are advantageously kept in the far field relative to the pattern of the reticle to avoid adversely affecting the quality of the image projected by the lithographic apparatus onto the substrate.

[0018] The material provided by the particle fixing device may include at least one of the following: molybdenum Mo, ruthenium Ru, zirconium Zr, boron B, cerium Ce, silicon Si, samarium Sm, praseodymium Pr, europium Eu, scandium Sc, promethium Pm, yttrium Y and rubidium Rb.

[0019] The material provided by the particle holding device may include at least one of carbon, oxygen, nitrogen and hydrogen.

[0020] The material provided by the particle holding device may include at least one of a metal carbonyl and a cyclopentadienyl metal.

[0021] The material provided by the particle holding device may include at least one of camphor, menthol, naphthalene and biphenyl.

[0022] The particle fixing device may be configured to provide an electron beam or a radiation beam to the pellicle membrane for fixing the particles to the pellicle membrane.

[0023] The electron beam or radiation beam may be configured to induce interaction between the material and the pellicle membrane and / or the particles and thereby fix the particles to the pellicle membrane.

[0024] The interactions may create and / or enhance attractive forces acting between the deposited material and the particles and / or pellicle membranes, and may include, for example, covalent bonds, metallic bonds, polar bonds, hydrogen bonds, van der Waals forces, and the like.

[0025] The particle holding device may be configured to direct the electron beam or radiation beam such that the electron beam or radiation beam passes through the pellicle membrane before being incident on the particles.

[0026] The electron beam or radiation beam may form a beam spot on the pellicle membrane having a diameter greater than about 0.1 μm. The electron beam or radiation beam may form a beam spot on the pellicle membrane having a diameter less than about 5 μm. Providing electron beams or radiation beams having these diameters may advantageously enable better management of thermal effects acting on the pellicle membrane. Providing electron beams or radiation beams having these diameters may advantageously reduce the range of scanning motion of the electron beam or radiation beam across the pellicle membrane.

[0027] The particle fixture may be configured to direct the electron beam or radiation beam to form a beam spot on the particle on the pellicle membrane. The outer boundary of the beam spot may be less than about 5 μm from the particle. The outer boundary of the beam spot may be less than about 1 μm from the particle.

[0028] The particle fixture may be configured to direct the electron beam to form a beam spot on the region of the pellicle membrane comprising the particles.The electron beam may have an energy between about 100 V and about 100 kV.

[0029] The pellicle membrane may be mounted to the reticle during use of the particle fixture.The electron beam may have an energy between about 0.5 keV and about 5 keV.

[0030] The system may also have a support configured to hold the reticle and a material delivery system configured to provide material in a gap between the reticle and the pellicle.

[0031] The system may also have a particle locator configured to determine a position of a particle on the pellicle membrane.

[0032] The particle positioner can be configured to generate a signal indicative of the location of the particle and provide the signal to a particle fixture. The particle fixture can be configured to use the signal to provide a material and / or an electron beam or a radiation beam to the location of the particle on the pellicle membrane. The electron beam or the radiation beam can be configured to irradiate only a portion of the pellicle membrane corresponding to the location of the particle. The irradiated portion of the pellicle membrane can have a diameter of less than about 5 μm (e.g., about 1 μm).

[0033] The particle locator can be configured to use an electron beam or a radiation beam to determine the position of a particle on the pellicle membrane.

[0034] The particle locator can be configured to detect secondary electrons and / or backscattered electrons generated by the electron beam or radiation beam interacting with the pellicle membrane and / or particles.

[0035] The particle locator may include an optical measurement system configured to determine the position of a particle on the pellicle membrane. The optical measurement system may include a radiation source for radiation scattered from the particle and a radiation detector for detecting radiation scattered by the particle.

[0036] The particle locator may include at least one of a bright field imaging device, a dark field imaging device, an atomic force microscope, and a capacitive particle detection component.

[0037] The particle positioner may be configured to position particles having a diameter between about 0.1 μm and about 5 μm.

[0038] The system may also have a first compartment for containing a material in a non-gaseous state. The system may also have a second compartment for containing a material in a gaseous state. The system may also have a third compartment for transmitting an electron beam or a radiation beam to the pellicle membrane.

[0039] The first compartment may include a semi-permeable barrier wall for preventing non-gaseous materials from reaching the pellicle membrane.

[0040] The pellicle membrane may form at least a portion of the second compartment.

[0041] The particle holding device may include a channel between the first compartment and the second compartment. The particle holding device may include a channel between the second compartment and the third compartment. The channel may be configured to transport gas and thereby enable suction and / or exhaust of the compartment.

[0042] The second compartment may be maintained at a pressure between about 0.001 Pa and about 1 Pa.

[0043] The third compartment may include a vacuum environment (e.g., having a vacuum of less than about 10 -5 The third compartment may include a low pressure (e.g., greater than about 10 -5 The vacuum environment and / or the low-pressure gaseous environment can advantageously reduce the extent of undesired deposition of material on the pellicle membrane (e.g., on the non-mask-facing surface of the pellicle membrane). The vacuum environment and / or the low-pressure gaseous environment can advantageously reduce the degradation of the pellicle membrane, for example, by providing a reaction force that at least partially offsets the change in the surface stress of the pellicle membrane.

[0044] The particle immobilization device may, for example, be configured to maintain a pressure difference of less than about 1 Pa between different sides of the pellicle membrane.

[0045] The particle holding device may include an electrical ground connected to the pellicle membrane. The electrically grounded pellicle membrane may advantageously reduce charging of the pellicle membrane by the electron beam.

[0046] The system may also have a housing configured to house the diaphragm diaphragm in a clean environment (eg, a clean environment having an ISO class of 2 or better).

[0047] The system may further have a pellicle membrane transfer device configured to mount the pellicle membrane to a reticle maintained in a clean environment after the particle fixing device has fixed the particles to the pellicle membrane.

[0048] According to a second aspect of the present invention, there is provided a method comprising securing particles to a pellicle membrane.

[0049] The method may further include irremovably securing the particles to the pellicle membrane.

[0050] The method may further include fixing particles to the reticle-facing surface of the pellicle membrane.

[0051] The method may further include providing a material to the pellicle membrane to secure the particles to the pellicle membrane.

[0052] The method may further include providing the material to the pellicle membrane such that the material has a size on the pellicle membrane that is less than about 10 μm.

[0053] The method may further include providing the material to the pellicle membrane such that the material has a thickness on the pellicle membrane of less than about 100 nm.

[0054] The method may further include providing an electron beam or a radiation beam to the pellicle membrane to fix the material and particles to the pellicle membrane.

[0055] The method may further include: directing an electron beam or a radiation beam to the pellicle membrane to form a beam spot having a diameter greater than about 0.1 μm on the pellicle membrane. The method may further include: directing an electron beam or a radiation beam to the pellicle membrane to form a beam spot having a diameter less than about 5 μm on the pellicle membrane.

[0056] The diameter of the electron beam or radiation beam can be selected at least in part depending on the size of the particles to be fixed to the pellicle membrane. For example, the electron beam can be used to determine the position of the particles on the pellicle membrane. After the position of the particles on the pellicle membrane has been determined, the diameter of the electron beam or radiation beam can be changed (e.g., reduced to about 100 nm) and the electron beam or radiation beam can be used to fix the particles to the pellicle membrane.

[0057] The method may further comprise using an electron beam or a radiation beam to induce interaction between the materials and / or the pellicle membrane or the particles and thereby fix the particles to the pellicle membrane.

[0058] The method may further include directing the electron beam or radiation beam so that the electron beam or radiation beam passes through the pellicle membrane before being incident on the particles.

[0059] The method may further include securing the particles to the pellicle during mounting of the pellicle to the reticle, and wherein the electron beam has an energy between about 0.5 keV and about 5 keV.

[0060] The method may further include providing a material in a space between the reticle and the pellicle.

[0061] The method may also include determining a location of the particle on the pellicle membrane.

[0062] The method may further include locating particles having a diameter greater than about 0.1 μm. The method may further include locating particles having a diameter less than about 5 μm.

[0063] The method may include: via a vacuum environment (e.g., less than about 10 -5 Alternatively, the method may further include: providing an electron beam or a radiation beam to the pellicle membrane via a compartment having a low pressure (e.g., greater than about 10 -5 The vacuum environment and / or the low-pressure gaseous environment can advantageously reduce the extent of undesired deposition of material on the pellicle membrane (e.g., on the non-reticle-facing surface of the pellicle membrane). The vacuum environment and / or the low-pressure gaseous environment can advantageously reduce the degradation of the pellicle membrane, for example, by providing a reaction force that at least partially offsets the change in the surface stress of the pellicle membrane.

[0064] The method may further include: maintaining the pellicle membrane in a clean environment after the particles have been fixed to the pellicle membrane. The method may further include: mounting the pellicle membrane to a reticle in a clean environment after the particles have been fixed to the pellicle membrane.

[0065] According to a third aspect of the invention there is provided a method of projecting a patterned radiation beam onto a substrate, the patterned radiation beam passing through a pellicle membrane prior to being incident on the substrate, wherein particles have been fixed to the pellicle membrane using the method of the second aspect of the invention.

[0066] According to a fourth aspect of the present invention there is provided a pellicle membrane comprising particles which have been fixed to the pellicle membrane using the method of the second aspect of the present invention.

[0067] According to a fifth aspect of the invention, the invention relates to the use of a system according to the first aspect for fixing particles to a pellicle membrane for subsequent use in a lithographic apparatus.

[0068] Any parts of any of the various aspects of the present invention may be combined in any manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which:

[0070] Figure 1 schematically depicts a lithography system including a radiation source, a lithography apparatus, and a pellicle according to an embodiment of the present invention;

[0071] Figure 2 schematically depicts a system for securing particles to a pellicle membrane according to an embodiment of the present invention;

[0072] Figure 3 schematically depicts an enlarged view of a pellicle membrane including particles that have been affixed to the pellicle membrane according to an embodiment of the present invention; and

[0073] Figure 4 A system for securing particles to a pellicle membrane mounted to a reticle according to an embodiment of the present invention is schematically depicted. DETAILED DESCRIPTION

[0074] Figure 1 A lithographic system comprising a radiation source SO, a lithographic apparatus LA and a pellicle 20 according to an embodiment of the invention is shown. The radiation source SO is configured to generate an EUV radiation beam B and to supply the EUV radiation beam B to the lithographic apparatus LA. The lithographic apparatus LA comprises an illumination system IL, a support structure MT configured to support a patterning device MA (e.g. a mask), a projection system PS, and a substrate table WT configured to support a substrate W.

[0075] The illumination system IL is configured to condition the EUV radiation beam B before it is incident on the patterning device MA. In addition, the illumination system IL may include a faceted field mirror arrangement 10 and a faceted pupil mirror arrangement 11. The faceted field mirror arrangement 10 and the faceted pupil mirror arrangement 11 together provide an EUV radiation beam B having a desired cross-sectional shape and a desired intensity distribution. In addition to or instead of the faceted field mirror arrangement 10 and the faceted pupil mirror arrangement 11, the illumination system IL may include other mirrors or arrangements.

[0076] After being so conditioned, the EUV radiation beam B interacts with the patterning device MA. As a result of this interaction, a patterned EUV radiation beam B' is generated. The projection system PS is configured to project the patterned EUV radiation beam B' onto a substrate W. For this purpose, the projection system PS may include a plurality of mirrors 13, 14 configured to project the patterned EUV radiation beam B' onto a substrate W held by a substrate table WT. The projection system PS may apply a reduction factor to the patterned EUV radiation beam B', thereby forming an image having features that are smaller than corresponding features on the patterning device MA. For example, a reduction factor of 4 or 8 may be applied. Although the projection system PS is illustrated as having only Figure 1 1 , but the projection system PS may comprise a different number of mirrors (eg six or eight mirrors).

[0077] The substrate W may include a previously formed pattern. In this case, the lithographic apparatus LA aligns an image formed by the patterned EUV radiation beam B′ with a pattern previously formed on the substrate W.

[0078] A relative vacuum, ie a small amount of gas (eg hydrogen) at a pressure well below atmospheric pressure, may be provided in the radiation source SO, in the illumination system IL and / or in the projection system PS.

[0079] The radiation source SO may be a laser produced plasma (LPP) source, a discharge produced plasma (DPP) source, a free electron laser (FEL) or any other radiation source capable of generating EUV radiation.

[0080] As previously discussed, particles may be incident on the pellicle membrane before the pellicle membrane is used in a lithographic apparatus. During lithographic exposure, some of the particles may travel from the pellicle membrane to the reticle and thereby adversely affect the quality of the lithographic exposure.

[0081] Figure 2 A system 22 for affixing particles 24 to a pellicle membrane 20 is schematically depicted in accordance with an embodiment of the present invention. The system 22 at least partially prepares the pellicle membrane 20 for subsequent use in a lithographic apparatus (e.g., Figure 1 The pellicle membrane 20 is mounted to a frame 23 including studs 25. The pellicle membrane 20 and the frame 23 may be referred to as a pellicle assembly. The pellicle assembly is configured to be removably mounted on the mask MA. Figure 2In the example of , the pellicle assembly is mounted on a base 29 of the system 22. Methods and systems for mounting the pellicle assembly to the mask MA and / or another surface (such as the base 29) are discussed in the international patent application WO / 2016079051, which is incorporated herein by reference in its entirety. The system 22 includes a particle fixture 26 configured to fix particles 24 to the pellicle membrane 20. The particles 24 can be described as contaminant particles. The particle fixture 26 can be configured to fix the particles 24 to the pellicle membrane 20 so that the particles 24 are not separated from the pellicle membrane 20 during the photolithography exposure. The particle fixture 26 can be configured to fix the particles 24 to the pellicle membrane 20 in an irremovable manner. That is, the particle fixture 26 can fix the particles 24 to the pellicle membrane 20 so that the particles 24 are fixed to the pellicle membrane 20 throughout the operating life of the pellicle membrane 20.

[0082] Particle fixing device 26 can be configured to fix particles 24 to reticle-facing surface 21 of pellicle membrane 20. Particles present on reticle-facing surface 21 of pellicle membrane 20 may have a greater risk of traveling from pellicle membrane 20 to reticle MA during photolithography exposure compared to particles present on opposite side 19 of pellicle membrane 20. This is at least in part because there is a shorter travel distance between reticle-facing surface 21 of pellicle membrane 20 and reticle MA compared to the distance between opposite surface 19 of pellicle membrane 20 and reticle MA. Fixing particles 24 to reticle-facing surface 21 of pellicle membrane 20 advantageously prevents these particles 24 from adversely affecting photolithography exposure.

[0083] The particle securing device 26 can be configured to provide a material 28 to the pellicle membrane 20 for securing the particle 24 to the pellicle membrane 20. The material 28 can be provided around the particle 24 so as to form a cover that captures and thereby secures the particle 24 to the pellicle membrane 20. Alternatively or in addition, the material 28 can be provided between the particle 24 and the pellicle membrane 20 and act as an adhesive layer between the particle 24 and the pellicle membrane 20. The material 28 can be used to increase the attractive force acting between the particle 24 and the pellicle membrane 20, so that the particle 24 becomes secured to the pellicle membrane 20. The material 28 can also or alternatively be used to introduce a new attractive force acting between the particle 24 and the pellicle membrane 20, so that the particle 24 becomes secured to the pellicle membrane 20. Referring to the following Figure 3 Describe these attractions in more detail.

[0084] The material 28, after being provided to the pellicle membrane 20, should not be large enough to adversely affect the lithographic exposure involving the pellicle membrane 20. That is, if the material 28 deposited on the pellicle membrane 20 is too thick and / or has too large a size in the plane of the pellicle membrane 20 (e.g., a length, diameter, major axis, etc. determined depending on the shape of the deposited material), there is a risk that the material 28 itself will be at least partially imaged onto the substrate during the lithographic exposure, thereby adversely affecting the lithographic exposure. The material 28, as well as the particles 24, should be kept in the far field relative to the pattern of the reticle to avoid adversely affecting the quality of the image projected by the lithographic equipment onto the substrate. The material 28 provided to the pellicle membrane 20 by the particle fixture 26 can have a size of less than about 10 μm on the pellicle membrane 10 in the plane of the pellicle membrane 20. The material 28 provided to the pellicle membrane 20 by the particle fixture 26 can have a size of less than about 1 μm in the plane of the pellicle membrane 20. If the thickness of the material 28 provided to the pellicle membrane 20 is too great, the material 28 may no longer be in the far field relative to the pattern of the mask MA and thereby adversely affect the quality of the image projected onto the substrate. The material 28 provided to the pellicle membrane 20 by the particle fixture 26 may have a thickness on the pellicle membrane 20 of less than about 100 nm. The material 28 provided to the pellicle membrane 20 by the particle fixture 26 may have a thickness on the pellicle membrane 20 of less than about 10 nm.

[0085] You will understand that Figure 2 It is merely a schematic representation of an embodiment of the invention, and the relative sizes of its features (eg, the size of particles 24, materials, and pellicle membrane 20) have been adjusted for purposes of illustrating the invention.

[0086] The material 28 provided by the particle fixture 26 may include one or more materials suitable for use when exposed to EUV radiation. For example, the material 28 may include at least one of the following: molybdenum Mo, ruthenium Ru, zirconium Zr, boron B, cerium Ce, silicon Si, samarium Sm, praseodymium Pr, europium Eu, scandium Sc, promethium Pm, yttrium Y and rubidium Rb. The material 28 may include one or more materials suitable for use in the presence of a hydrogen plasma that may be generated by EUV radiation. For example, the material 28 provided by the particle fixture 26 may include at least one of carbon, oxygen, nitrogen and hydrogen. Even if the material is partially etched by the hydrogen plasma, it still has a reduced risk of leaving any contaminants (e.g., molecular contaminants) on the pellicle membrane 20 and / or the mask MA. The material 28 provided by the particle fixture 26 may include a carbonyl metal (e.g., Mo(CO)6 or Ru3(CO) 12 ) and at least one of a cyclopentadienyl metal (eg, Ru(C5H5)2). The material 28 provided by the particle fixing device 26 may include at least one of camphor, menthol, naphthalene, and biphenyl.

[0087] The particle fixing device 26 can be configured to provide an electron beam or a radiation beam 30 to the pellicle membrane 20 for fixing the material 28 and the particles 24 to the pellicle membrane 20. The electron beam or the radiation beam 30 can be configured to induce an interaction between the material 28 and the pellicle membrane 20 and / or the particles 24, and thereby fix the particles 24 to the pellicle membrane 20.

[0088] For example, the pellicle fixing device 26 may use an electron beam 30 in conjunction with the material 28 to perform electron beam induced deposition to fix the particles 24 to the pellicle membrane 20. Figure 3 Electron beam induced deposition is discussed in more detail. The electron beam 30 may have an energy greater than about 200 eV. The electron beam 30 may have an energy less than about 100 keV. The electron beam 30 may have an energy in the range of about 1 keV to about 50 keV. The electron beam 30 may have an energy in the range of about 10 keV to about 30 keV.

[0089] As another example, pellicle securing device 26 may use radiation beam 30 in conjunction with material 28 to perform radiation beam induced deposition to secure particles 24 to pellicle membrane 20. Radiation beam 30 may have a wavelength greater than about 100 nm. Radiation beam 30 may have a wavelength less than about 200 nm.

[0090] Particle fixture 26 may be configured to direct electron beam or radiation beam 30 to form beam spot 27 on pellicle membrane 20. For example, beam spot 27 may have a diameter greater than about 0.1 μm. For example, beam spot 27 may have a diameter less than about 5 μm on pellicle membrane 20.

[0091] The particle fixture 26 can be configured to direct the electron beam or radiation beam 30 to form a beam spot 27 on the particle 24 on the pellicle membrane 20. The outer boundaries 31a, 31b of the beam spot 27 can be less than about 5 μm from the particle 24 in the plane of the pellicle membrane 20. The outer boundaries 31a, 31b of the beam spot 27 can be less than about 1 μm from the particle 24 in the plane of the pellicle membrane 20.

[0092] The system 22 may also have a particle locator 32 configured to determine the position of the particle 24 on the pellicle membrane 20. Figure 2 In the illustrated example embodiment, a portion of the pellicle fixture 26 is used as a particle locator 32. The particle locator 32 can be configured to use the electron beam or radiation beam 30 to determine the position of the particle 24 on the pellicle membrane. That is, the electron beam or radiation beam 30 used to fix the particle 24 to the pellicle membrane 20 can also be used to locate the particle 24 on the pellicle membrane 20.

[0093] The particle locator 32 can be configured to generate a signal indicating the position of the particle 24. The particle locator 32 can provide the signal to the particle fixture 26. The particle fixture 26 can be configured to use the signal to provide the material 28 to the position of the particle 24 on the pellicle membrane 20. The particle fixture 26 can be configured to use the signal to provide the electron beam or radiation beam 30 to the position of the particle 24 on the pellicle membrane 20. For example, the particle locator 32 can include a scanning electron microscope that uses the electron beam 30 to determine the position of the particle 24 on the pellicle membrane 20. The scanning electron microscope can be used to perform a fine scan to determine the position of the particle 24 on the pellicle membrane 20 with a desired accuracy. The accuracy of the scanning electron microscope can be selected at least in part depending on the size of the particle and / or the size of the expected deposition of the material on the pellicle membrane. The accuracy of the scanning electron microscope can be selected at least in part depending on the larger value selected from the size of the particle and / or the size of the expected deposition on the pellicle membrane. For example, a scanning electron microscope may have an accuracy greater than about 10 μm (eg, at least 1 μm).

[0094] The particle locator 32 may be configured to detect secondary electrons and / or backscattered electrons (not shown) generated by the electron beam or radiation beam 30 interacting with the pellicle membrane 20 and / or the particles 24 .

[0095] The particle locator 32 may include an independent device for locating particles on the pellicle membrane 20. The particle locator 32 may include, for example, an optical measurement system, a bright field imaging device, a dark field imaging device, an atomic force microscope, and a capacitive particle detection member. Figure 4 A system for securing particles to a pellicle membrane is discussed, the system comprising a particle positioner having an optical measurement system.

[0096] It has been found that particles having a diameter between about 0.1 μm and about 5 μm have been found to travel from the pellicle membrane to the mask during photolithographic exposure. These particles tend to be metal particles (e.g., ruthenium particles) and / or ceramic particles (e.g., Al2O3 and / or SiO2). The particle positioner 32 can be configured to position particles 24 having a diameter between about 0.1 μm and about 5 μm. The particle positioner 32 can be configured to position metal particles and / or ceramic particles. The particle positioner 32 can be configured to position any one of ruthenium particles, Al2O3 particles, and SiO2 particles.

[0097] The system 22 may also have a first compartment 34 for containing a material 28 in a non-gaseous state 35 and a second compartment 36 for containing a material 28 in a gaseous state 37. The first compartment 34 may be located within a base 29 of the system 22. The base 29 may be configured to electrically ground the pellicle frame 23. The pellicle frame 23 may be mounted to the base 29 via studs 25 (e.g., the same studs 25 used to mount the frame 23 to the mask MA). The non-gaseous material 35 may be a solid or a liquid. The liquid material contained in the first compartment 34 may, for example, have a relative humidity of about 1 g / cm -3 and about 10gcm -3 The concentration between.

[0098] The use of a material 35 that is solid at room temperature may be more preferred due to improved ease of handling and deposition. The first compartment 34 may include a semi-permeable barrier wall 40 for preventing the non-gaseous material 35 from reaching the pellicle membrane 20. That is, when the material is in a gaseous state 37, the material can leave the first compartment 34. However, the semi-permeable barrier wall 40 is used to prevent the non-gaseous material 35 from entering the second chamber 36 (e.g., via sparging and / or boiling), thereby reducing the risk of damaging the pellicle membrane 20.

[0099] The pellicle membrane 20 can form at least a portion of the second compartment 36. The second compartment 36 can prevent the material 28 (gaseous or non-gaseous) from leaving the second compartment 36 and interfering with the electron beam or radiation beam 30. The second compartment 36 may not be completely sealed. For example, one or more gaps or channels (not shown) may exist in or around the studs 25 of the frame 23 to allow suction and / or exhaust of the second compartment 36. When the second compartment 36 is not completely sealed, some leakage of material to the third compartment 39 may occur. However, one or more gaps can be sufficiently small so that any material leaking from the second compartment 36 to the third compartment 39 is removed from the third compartment 39 by suction that creates and maintains a vacuum environment in the third compartment 39. The third compartment 39 is the compartment through which the electron beam or radiation beam is transmitted to the pellicle membrane 20. The second compartment 36 can be maintained at a pressure greater than about 0.001Pa. The second compartment 36 can be maintained at a pressure less than about 1Pa.

[0100] The particle fixture 26 can be configured to direct the electron beam or radiation beam 30 so that the electron beam or radiation beam 30 passes through the pellicle membrane 20 before being incident on the particle 24. This advantageously allows relatively high partial pressures (e.g., between about 100 Pa and about 10 -3 Pa) is present in the first compartment 34, which enables the non-gaseous material 35 to become gaseous 37 and travel to the second compartment 36 for deposition on the particles 24. This also advantageously allows a vacuum environment (e.g., less than about 10 -5A pressure of about 100 Pa (Pa) is maintained in the third compartment 39 so that the electron beam or radiation beam 30 can operate without being blocked by matter. The pellicle membrane 20 may be able to withstand a pressure of up to about 100 Pa. Thus, the pressure difference between the third compartment 39 and the second compartment 36 is not large enough to damage the pellicle membrane 20. The particle holding device 26 may be configured to maintain a pressure difference of less than about 1 Pa between different sides of the pellicle membrane 20.

[0101] The second compartment 36 may be connected to the third compartment 39 via a channel. The channel may be configured to convey gas and thereby enable suction and / or exhaust of the second compartment 36.

[0102] The third compartment 39 may include a portion having a diameter greater than about 10 -5 Pa and a gaseous environment with a pressure less than about 0.1 Pa. The third compartment may include at least one of H 2 , H 2 O, and O 2 in gaseous form.

[0103] Particle holding device 26 may include an electrical ground (not shown), such as a wire connected to pellicle diaphragm 20 .

[0104] The system 22 may also have a housing 42 configured to house the diaphragm 20 in a clean environment 44. The clean environment 44 in the housing 42 may, for example, have an ISO class of 2 or better. The clean environment 44 may include a vacuum. Alternatively, the clean environment 44 may include a clean gas, such as argon, nitrogen, clean air, ultra-clean air, etc.

[0105] The system 22 may also have a pellicle membrane transfer device 46 configured to mount the pellicle membrane 20 to the mask MA held in the clean environment 44 after the particle fixture 26 has fixed the particles 24 to the pellicle membrane 20. The pellicle membrane transfer device 46 may be configured to move the pellicle assembly (i.e., the pellicle membrane 20 and the frame 23) from the base 29 and mount the pellicle assembly on the mask MA.

[0106] Figure 3 Schematically depicted is an enlarged view of a pellicle membrane 20 including particles 24 that have been affixed to the pellicle membrane 20 in accordance with an embodiment of the present invention. Figure 3Materials 37, 50, 52 in three different forms distinguished by different hatching are shown provided to the pellicle membrane 20 by a particle fixing device (not shown). The gaseous material 37 is represented by mesh hatching, the adsorbed material 50 is represented by horizontal hatching, and the deposited material 52 is represented by vertical hatching. The three different forms of materials 37, 50, 52 correspond to different stages in the particle fixing process. The gaseous material 37 is provided from a first compartment (not shown) to a second compartment (not shown) via a semi-permeable membrane (not shown). The gaseous material 37 can be incident on the pellicle membrane 20 and the particles 24 and become adsorbed on the pellicle membrane 20 and / or the particles 24. An electron beam or radiation beam 30 can be provided to the location of the particles 24 on the pellicle membrane 20. The electron beam or radiation beam 30 can be used to induce interaction between the adsorbed material 50 and the pellicle membrane 20 and / or the particles 24, and thereby fix the particles 24 to the pellicle membrane 20. The electron beam or radiation beam 30 may be used to induce dissociation of adsorbed material 37 on the particle 24 and / or pellicle membrane 20. The dissociated material (i.e., the deposited material 52) may introduce and / or increase attractive forces acting between the particle 24 and the pellicle membrane 20, and thereby fix the particle 24 to the pellicle membrane 20. The attractive forces acting between the deposited material 52 and the particle 24 and / or the pellicle membrane 20 may, for example, include covalent bonds, metallic bonds, polar bonds, hydrogen bonds, van der Waals forces, etc. The particle 24 fixed by the deposited material 52 (e.g., by embedding between about 10 nm and about 100 nm of the deposited material) may be fixed to the pellicle membrane 20 with a force between about 10 and 100 times stronger than the force when the particle 24 is not fixed to the pellicle membrane 20. This force reduces the risk of the particle 24 detaching from the pellicle membrane 20 and traveling toward the mask (not shown) during photolithographic exposure.

[0107] At least a portion of electron beam 30 may be partially scattered and / or may be partially blocked by pellicle membrane 20. At least a portion of electron beam 30 may be transmitted through pellicle membrane 20 and incident on particle 24. At least a portion 56 of electron beam 30 may be transmitted through particle 24.

[0108] The electron beam 30 may have an energy in the range of about 10 keV to about 30 keV. The pellicle membrane 20 may absorb less than about 10% of the energy of the electron beam 30. The energy of the electron beam 30 absorbed by the pellicle membrane 20 may generate an avalanche of scattered electrons within the pellicle membrane 20 that can induce dissociation of the adsorbent material 50, thereby forming a deposited material 52 for fixing the particle 24 to the pellicle membrane 20.

[0109] The deposition rate of material 52 may be about 0.01 μm per nA* minute. 3 About 0.1 μm per nA* minute 3 For example, in the plane of the pellicle membrane there is about 1 μm2 Deposition of material 52 having an area of ​​10 nm and a thickness between about 100 nm can be formed on the pellicle membrane 20 in less than one minute using an electron beam 30 having a current of about 1 nA. The deposition rate may be limited at least in part by the electron flux of the electron beam 30. This means that a lower pressure may be used for the second compartment (not shown) because the deposition rate may not be limited by the pressure.

[0110] The power of the electron beam 30 dissipated in the diaphragm 20 may be about 1 W cm -2 This power may be within the radiation cooling limit of the pellicle membrane 20, so the pellicle membrane 20 may not be damaged by the electron beam 30. An electron beam 30 with a lower current may be preferably used to increase the adsorption of the material 50 within the electron beam 30 incident on the pellicle membrane 20.

[0111] It will be understood that Figure 3 It is merely a schematic representation of an embodiment of the invention, and the relative sizes of its features (eg, the sizes of particles 24, materials 37, 50, 52, and pellicle membrane 20) have been adjusted for purposes of illustrating the invention.

[0112] Figure 4 A system 60 for securing particles 24 to a pellicle membrane 20 mounted to a reticle MA according to an embodiment of the present invention is schematically depicted. Pellicle membrane 20 is mounted to a frame 23 including studs 25. Pellicle membrane 20 and frame 23 may be referred to as a pellicle assembly. The pellicle assembly is configured to be removably mounted on a reticle MA.

[0113] The system 60 may also have a housing 42 configured to house the diaphragm 20 in a clean environment 44. The clean environment 44 may include a vacuum. Alternatively, the clean environment 44 may include a clean gas, such as argon, nitrogen, clean air, ultra-clean air, or the like.

[0114] To reduce or prevent deposition of material 28 on mask MA, Figure 2 and Figure 3 Compared to the embodiment of the present invention shown, the energy of the electron beam or radiation beam (not shown) is reduced. For example, the electron beam can have an energy greater than about 0.5 keV. For example, the electron beam 30 can have an energy less than about 5 keV. The reduction in the energy of the electron beam can increase the number of electrons blocked by the particles 24 and / or the pellicle membrane 20, thereby reducing the number of electrons reaching the mask MA.

[0115] The electron beam or radiation beam may have a desired numerical aperture to reduce the electron flux or radiation flux reaching the reticle MA. For example, in the case of an electron beam, the electron flux at the reticle MA may be between about 100 and about 1000 times lower than the electron flux incident on the pellicle membrane 20 .

[0116] The deposition of material 28 may be proportional to the electron flux of the electron beam. Therefore, the deposition of material 28 at the mask MA may be reduced or completely prevented. For example, a particle 24 having a density of about 1 μm may be deposited adjacent to the particle 24. 2 The time spent on a material layer with an area of ​​about 10 nm×(1 μm) and a thickness of about 10 μm 2 A material layer with an area of ​​about 100 nm and a thickness of about 0.1 nm may be deposited on the mask MA. Deposition of this size may not affect the quality of the image of the mask pattern formed on the substrate during photolithography exposure.

[0117] The system 60 may include a support 70 configured to hold the mask MA and a material delivery system 72 configured to provide the material 28 in a gap 74 between the mask MA and the pellicle membrane 20. The system 60 may also include a first compartment 34 for containing the material 28 in a non-gaseous state 35 and a second compartment 36 for containing the material 28 in a gaseous state 37. The first compartment 34 may include a semi-permeable barrier wall 40 for preventing the non-gaseous material 35 from reaching the pellicle membrane 20.

[0118] exist Figure 4 In an example of the present invention, system 60 includes an optical measurement system 80. Optical measurement system 80 is configured to determine the position of particle 24 on pellicle membrane 20. Optical measurement system 80 may include: a radiation source 82 for radiation 84 scattered from particle 24; and a radiation detector 86 for detecting radiation 88 scattered by particle 24. The position of particle 24 determined by optical measurement system 80 may be referenced to, for example, edge 90 of a corner of the pellicle frame and / or edge 92 of a corner of the pellicle membrane and / or surface 94 of the support. The electron beam or radiation beam of pellicle fixture 26 may use the same position reference system.

[0119] Optical measurement system 80 may be configured to perform a coarse search for particle 24. After the coarse position of particle 24 has been determined by optical measurement system 80, an electron beam or radiation beam (not shown) of particle fixture 26 may be used to perform a fine search for particle 24 at the coarse position.

[0120] In either embodiment, the supply of material 28 by pellicle securing device 26 may be adjustable and / or time dependent.

[0121] Although specific reference may be made herein to the use of lithographic equipment in IC manufacturing, it should be understood that the lithographic equipment described herein may have other applications. Possible other applications include: manufacturing integrated optical systems, guidance and detection patterns for magnetic domain memory, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads, etc.

[0122] Although embodiments of the present invention may be specifically referenced herein in the context of lithographic equipment, embodiments of the present invention may be used in other equipment. Embodiments of the present invention may form part of a mask detection device, a measurement device, or any device that measures or processes an object such as a wafer (or other substrate) or a mask (or other patterning device). These devices may be collectively referred to as lithographic tools. The lithographic tools may use vacuum conditions or ambient (non-vacuum) conditions.

[0123] Where the context allows, embodiments of the present invention may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the present invention may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a form that can be read by a machine (e.g., a computing device). For example, a machine-readable medium may include a read-only memory (ROM); a random access memory (RAM); a magnetic storage medium; an optical storage medium; a flash memory device; an electrical, optical, acoustic, or other form of propagation signal (e.g., a carrier wave, an infrared signal, a digital signal, etc.), etc. In addition, firmware, software, programs, instructions may be described herein as performing specific actions. However, it should be understood that such descriptions are for convenience purposes only, and such actions are in fact performed by a computing device, a processor, a controller, or other device that executes firmware, software, programs, instructions, etc., and doing so may cause an actuator or other device to interact with the physical world.

[0124] Embodiments of aspects of the present invention may be described according to one or more of the following aspects:

[0125] 1. A system for fixing particles to a pellicle membrane for subsequent use in a lithographic apparatus, the system comprising a particle fixing device configured to fix the particles to the pellicle membrane.

[0126] 2. The system of aspect 1, wherein the particle securing device is configured to irremovably secure the particle to the pellicle membrane.

[0127] 3. The system of aspect 1 or aspect 2, wherein the particle fixing device is configured to fix the particles to the reticle-facing surface of the pellicle membrane.

[0128] 4. The system of any one of aspects 1 to 3, wherein the particle securing device is configured to provide a material to the pellicle membrane for securing the particles to the pellicle membrane.

[0129] 5. The system of aspect 4, wherein the material provided to the pellicle membrane by the particle holding device has a size in the plane of the pellicle membrane that is less than about 10 μm.

[0130] 6. The system of aspect 4 or aspect 5, wherein the material provided to the pellicle membrane by the particle holding device has a thickness on the pellicle membrane of less than about 100 nm.

[0131] 7. A system as described in any of Aspects 4 to 6, wherein the material provided by the particle fixing device includes at least one of the following: molybdenum Mo, ruthenium Ru, zirconium Zr, boron B, cerium Ce, silicon Si, samarium Sm, praseodymium Pr, europium Eu, scandium Sc, promethium Pm, yttrium Y and rubidium Rb.

[0132] 8. The system of any one of aspects 4 to 7, wherein the material provided by the particle fixture comprises at least one of carbon, oxygen, nitrogen, and hydrogen.

[0133] 9. The system of any one of aspects 4 to 8, wherein the material provided by the particle fixture comprises at least one of a metal carbonyl and a cyclopentadienyl metal.

[0134] 10. The system of any one of aspects 4 to 9, wherein the material provided by the particle holding device comprises at least one of camphor, menthol, naphthalene, and biphenyl.

[0135] 11. The system of any preceding aspect, wherein the particle fixing device is configured to provide an electron beam or a radiation beam to the pellicle membrane for fixing the particles to the pellicle membrane.

[0136] 12. The system of aspect 11, wherein the electron beam or the radiation beam is configured to induce interaction between the material and the pellicle membrane and / or the particles and thereby fix the particles to the pellicle membrane.

[0137] 13. The system of aspect 11 or aspect 12, wherein the particle holding device is configured to direct the electron beam or the radiation beam so that the electron beam or the radiation beam passes through the pellicle membrane before being incident on the particle.

[0138] 14. The system of any one of aspects 11 to 13, wherein the particle fixture is configured to direct the electron beam or the radiation beam to form a beam spot having a diameter between about 0.1 μm and about 5 μm on the pellicle membrane.

[0139] 15. A system as described in any of Aspects 11 to 14, wherein the particle holding device is configured to guide the electron beam or the radiation beam to form a beam spot on the particle on the pellicle membrane, and wherein the outer boundary of the beam spot is less than about 5 μm from the particle, and optionally wherein the outer boundary of the beam spot is less than about 1 μm from the particle.

[0140] 16. A system as described in any of aspects 11 to 14, wherein the particle holding device is configured to direct the electron beam to form a beam spot on the area of ​​the pellicle membrane including the particles, and wherein the electron beam has an energy between about 100 V and about 100 kV.

[0141] 17. The system of any of aspects 11 to 15, wherein the pellicle membrane is mounted to a reticle during use of the particle fixture, and wherein the electron beam has an energy between about 0.5 keV and about 5 keV.

[0142] 18. The system of clause 17, further comprising: a support configured to hold the reticle; and a material delivery system configured to provide the material in a gap between the reticle and the pellicle.

[0143] 19. The system of any preceding aspect, further comprising a particle locator configured to determine a position of the particle on the pellicle membrane.

[0144] 20. A system as described in aspect 19, wherein the particle locator is configured to generate a signal indicative of the position of the particle and provide the signal to the particle retaining device, and wherein the particle retaining device is configured to use the signal to provide the material and / or the electron beam or the radiation beam to the position of the particle on the pellicle diaphragm.

[0145] 21. The system of aspect 19 or aspect 20, wherein the particle locator is configured to determine the position of the particle on the pellicle membrane using the electron beam or the radiation beam.

[0146] 22. The system of aspect 21, wherein the particle locator is configured to detect secondary electrons and / or backscattered electrons generated by the electron beam or the radiation beam interacting with the pellicle membrane and / or the particles.

[0147] 23. A system as described in any of Aspects 19 to 22, wherein the particle locator includes an optical measurement system, which is configured to determine the position of the particle on the pellicle diaphragm, and the optical measurement system includes: a radiation source, which is used to scatter radiation from the particle; and a radiation detector, which is used to detect radiation scattered by the particle.

[0148] 24. The system of any one of aspects 19 to 23, wherein the particle locator comprises at least one of a bright field imaging device, a dark field imaging device, an atomic force microscope, and a capacitive particle detection component.

[0149] 25. The system of any of aspects 19 to 24, wherein the particle positioner is configured to position particles having a diameter between about 0.1 μm and about 5 μm.

[0150] 26. The system as described in any one of Aspects 4 to 25 further includes: a first compartment, wherein the first compartment is used to contain the material in a non-gaseous state; a second compartment, wherein the second compartment is used to contain the material in a gaseous state; and a third compartment, wherein the third compartment is used to transmit the electron beam or the radiation beam to the pellicle diaphragm.

[0151] 27. The system of aspect 26, wherein the first compartment comprises a semi-permeable barrier wall for preventing non-gaseous materials from reaching the pellicle membrane.

[0152] 28. The system of aspect 26 or aspect 27, wherein the pellicle membrane forms at least a portion of the second compartment.

[0153] 29. The system of any one of aspects 26 to 28, wherein the second compartment is connected to the third compartment via a channel, and wherein the channel is configured to allow suction and / or exhaust of the second compartment.

[0154] 30. The system of any of aspects 26 to 29, wherein the second compartment is maintained at a pressure between about 0.001 Pa and about 1 Pa.

[0155] 31. The system of any one of aspects 26 to 30, wherein the third compartment comprises a - 5 Pa pressure vacuum environment.

[0156] 32. The system of any one of aspects 26 to 30, wherein the third compartment comprises a - 5 Pa and a gaseous environment with a pressure less than about 0.1 Pa.

[0157] 33. The system of aspect 32, wherein the third compartment comprises at least one of H2, H2O, and O2.

[0158] 34. The system of any preceding aspect, wherein the particle holding device is configured to maintain a pressure differential of less than about 1 Pa between different sides of the pellicle membrane.

[0159] 35. The system of any preceding aspect, wherein the particle immobilization device comprises an electrical ground connected to the pellicle membrane.

[0160] 36. The system of any preceding aspect, further comprising a housing configured to house the diaphragm membrane in a clean environment.

[0161] 37. The system of aspect 36, further comprising: a pellicle membrane conveying device configured to mount the pellicle membrane to a mask maintained in the clean environment after the particle fixing device has fixed the particles to the pellicle membrane.

[0162] 38. A method comprising affixing particles to a pellicle membrane.

[0163] 39. The method of aspect 38, further comprising: irremovably securing the particles to the pellicle membrane.

[0164] 40. The method of clause 38 or clause 39, further comprising: fixing the particles to a reticle-facing surface of the pellicle membrane.

[0165] 41. The method of any of aspects 38 to 40, further comprising providing a material to the pellicle membrane to secure the particles to the pellicle membrane.

[0166] 42. The method of clause 41, further comprising providing the material to the pellicle membrane such that the material has a dimension in the plane of the pellicle membrane that is less than about 10 μm.

[0167] 43. The method of aspect 41 or aspect 42, further comprising: providing the material to the pellicle membrane such that the material has a thickness on the pellicle membrane of less than about 100 nm.

[0168] 44. The method of any one of aspects 41 to 43, further comprising: providing an electron beam or a radiation beam to the pellicle membrane to fix the material and the particles to the pellicle membrane.

[0169] 45. The method of clause 44, further comprising directing the electron beam or the radiation beam toward the pellicle membrane to form a beam spot having a diameter between about 0.1 μm and about 5 μm on the pellicle membrane.

[0170] 46. ​​The method of aspect 44 or aspect 45, further comprising: using the electron beam or the radiation beam to induce interaction between the material and / or the pellicle membrane or the particles, and thereby fix the particles to the pellicle membrane.

[0171] 47. The method of any one of aspects 44 to 46, further comprising directing the electron beam or the radiation beam so that the electron beam or the radiation beam passes through the pellicle membrane before being incident on the particles.

[0172] 48. The method of any of clauses 44 to 47, further comprising: fixing the particles to the pellicle membrane during mounting of the pellicle membrane to a reticle, and wherein the electron beam has an energy between about 0.5 keV and about 5 keV.

[0173] 49. The method of clause 48, further comprising: providing the material in a space between the reticle and the pellicle.

[0174] 50. The method of any one of aspects 38 to 49, further comprising: determining a position of the particle on the pellicle membrane.

[0175] 51. The method of clause 50, further comprising positioning particles having a diameter between about 0.1 μm and about 5 μm on the pellicle membrane.

[0176] 52. The method of any one of aspects 44 to 51, further comprising: -5 A chamber with a vacuum environment of a pressure of Pa provides the electron beam or the radiation beam to the pellicle diaphragm.

[0177] 53. The method of any one of aspects 44 to 52, further comprising: -5 A compartment having a gaseous environment at a pressure of about 1.0 Pa and less than about 0.1 Pa provides the electron beam or the radiation beam to the pellicle membrane.

[0178] 54. The method of aspect 53, further comprising: providing at least one of H2, H2O, and O2 to the compartment.

[0179] 55. The method of any one of aspects 38 to 54, further comprising maintaining the pellicle membrane in a clean environment after the particles have been affixed to the pellicle membrane.

[0180] 56. A method of projecting a patterned radiation beam onto a substrate, the patterned radiation beam passing through a pellicle membrane before being incident on the substrate, wherein particles have been fixed to the pellicle membrane using a method as described in any of aspects 38 to 55.

[0181] 57. A pellicle membrane comprising particles that have been affixed to the pellicle membrane using the method of any one of aspects 38 to 55.

[0182] 58. Use of the system of any one of aspects 1 to 37 for fixing particles to a pellicle membrane for subsequent use in a lithographic apparatus.

[0183] Although specific embodiments of the present invention have been described above, it will be appreciated that the present invention may be practiced in other ways than those described. The above description is intended to be illustrative, not restrictive. Therefore, it will be apparent to those skilled in the art that the described invention may be modified without departing from the scope of the claims set forth below.

Claims

1. A system for fixing particles to a pellicle membrane for subsequent use in a lithography device, the system comprising a particle fixing device, the particle fixing device being configured to fix the particles to the pellicle membrane, wherein the particle fixing device is configured to provide an electron beam or a radiation beam to the pellicle membrane for fixing the particles to the pellicle membrane.

2. The system of claim 1, wherein: The particle securing device is configured to irremovably secure the particles to the pellicle membrane.

3. A system as claimed in claim 1 or claim 2, wherein: The particle fixing device is configured to fix the particles to the reticle-facing surface of the pellicle membrane.

4. A system as claimed in claim 1 or claim 2, wherein: The particle fixing device is configured to provide a material to the pellicle membrane for fixing the particles to the pellicle membrane.

5. The system of claim 4, wherein: The material provided to the pellicle membrane by the particle immobilization device has a size in the plane of the pellicle membrane that is less than 10 μm.

6. The system of claim 4, wherein: The material provided to the pellicle membrane by the particle immobilization device has a thickness on the pellicle membrane of less than 100 nm.

7. The system of claim 4, wherein: The material provided by the particle fixing device includes at least one of the following: molybdenum Mo, ruthenium Ru, zirconium Zr, boron B, cerium Ce, silicon Si, samarium Sm, praseodymium Pr, europium Eu, scandium Sc, promethium Pm, yttrium Y and rubidium Rb.

8. The system of claim 4, wherein: The material provided by the particle holding device includes at least one of carbon, oxygen, nitrogen and hydrogen.

9. The system of claim 4, wherein: The material provided by the particle holding device includes at least one of a metal carbonyl and a cyclopentadienyl metal.

10. The system of claim 4, wherein: The material provided by the particle holding device includes at least one of camphor, menthol, naphthalene and biphenyl.

11. The system of claim 1, wherein: The electron beam or the radiation beam is configured to induce interaction between a material and the pellicle membrane and / or the particles and thereby fix the particles to the pellicle membrane.

12. The system of claim 1 or claim 11, wherein: The particle holding device is configured to direct the electron beam or the radiation beam such that the electron beam or the radiation beam passes through the pellicle membrane before being incident on the particles.

13. The system of claim 1 or claim 11, wherein: The particle holding device is configured to direct the electron beam or the radiation beam to form a beam spot having a diameter between 0.1 μm and 5 μm on the pellicle membrane.

14. The system of claim 1 or claim 11, wherein: The particle holding device is configured to direct the electron beam or the radiation beam to form a beam spot on the particle on the pellicle membrane, and wherein an outer boundary of the beam spot is less than 5 μm from the particle.

15. The system of claim 14, wherein: The outer boundary of the beam spot is less than 1 μm from the particle.

16. The system of claim 1 or claim 11, wherein: The particle holding device is configured to direct the electron beam to form a beam spot on a region of the pellicle membrane including the particles, and wherein the electron beam has an energy between 100 V and 100 kV.

17. The system of claim 1 or claim 11, wherein: The pellicle membrane is mounted to a reticle during use of the particle fixture, and wherein the electron beam has an energy between 0.5 keV and 5 keV.

18. The system of claim 17, further comprising: a support configured to hold the reticle; and a material delivery system configured to provide the material in a gap between the reticle and the pellicle.

19. The system of claim 1 or claim 2, further comprising a particle locator configured to determine a position of the particle on the pellicle membrane.

20. The system of claim 19, wherein: The particle positioner is configured to generate a signal indicative of the position of the particle and provide the signal to the particle fixture, and wherein the particle fixture is configured to use the signal to provide material and / or the electron beam or the radiation beam to the position of the particle on the pellicle membrane.

21. The system of claim 19, wherein: The particle locator is configured to determine a position of the particle on the pellicle membrane using the electron beam or the radiation beam.

22. The system of claim 21, wherein: The particle locator is configured to detect secondary electrons and / or backscattered electrons generated by the electron beam or the radiation beam interacting with the pellicle membrane and / or the particles.

23. The system of claim 19, wherein: The particle locator comprises an optical measurement system configured to determine the position of the particle on the pellicle membrane, the optical measurement system comprising: a radiation source for scattering radiation from the particle; and a radiation detector for detecting radiation scattered by the particle.

24. The system of claim 19, wherein: The particle locator includes at least one of a bright field imaging device, a dark field imaging device, an atomic force microscope, and a capacitive particle detection component.

25. The system of claim 19, wherein: The particle positioner is configured to position particles having a diameter between 0.1 μm and 5 μm.

26. The system of claim 4, further comprising: a first compartment, the first compartment being used to contain the material in a non-gaseous state; a second compartment, the second compartment being used to contain the material in a gaseous state; and a third compartment for transmitting the electron beam or the radiation beam to the pellicle membrane.

27. The system of claim 26, wherein: The first compartment includes a semi-permeable barrier wall for preventing non-gaseous materials from reaching the pellicle membrane.

28. The system of claim 26, wherein: The pellicle membrane forms at least a portion of the second compartment.

29. The system of claim 26, wherein: The second compartment is connected to the third compartment via a channel, and wherein the channel is configured to allow suction and / or exhaust of the second compartment.

30. The system of claim 26, wherein: The second compartment is maintained at a pressure between 0.001 Pa and 1 Pa.

31. The system of claim 26, wherein: The third compartment includes a -5 Pa pressure vacuum environment.

32. The system of claim 26, wherein: The third compartment includes a -5 Pa and a gaseous environment with a pressure less than 0.1 Pa.

33. The system of claim 32, wherein: The third compartment contains at least one of H2, H2O and O2.

34. The system of claim 1 or claim 2, wherein: The particle holding device is configured to maintain a pressure difference of less than 1 Pa between different sides of the diaphragm membrane.

35. The system of claim 1 or claim 2, wherein: The particle holding device includes an electrical ground connected to the pellicle diaphragm.

36. The system of claim 1 or claim 2, further comprising a housing configured to house the diaphragm membrane in a clean environment.

37. The system of claim 36, further comprising: A pellicle membrane conveying device is configured to mount the pellicle membrane to a mask maintained in the clean environment after the particle fixing device has fixed the particles to the pellicle membrane.

38. A method of fixing particles to a pellicle membrane, the method comprising providing an electron beam or a radiation beam to the pellicle membrane to fix the particles to the pellicle membrane.

39. The method of claim 38, further comprising: The particles are irremovably secured to the pellicle membrane.

40. The method of claim 38 or claim 39, further comprising: The particles are fixed to the reticle-facing surface of the pellicle membrane.

41. The method of any one of claims 38 or 39, further comprising: A material is provided to the pellicle membrane to secure the particles to the pellicle membrane.

42. The method of claim 41, further comprising: The material is provided to the pellicle membrane such that the material has a size of less than 10 μm in the plane of the pellicle membrane.

43. The method of claim 41, further comprising: The material is provided to the pellicle membrane such that the material has a thickness of less than 100 nm on the pellicle membrane.

44. The method of claim 41, further comprising: An electron beam or a radiation beam is provided to the pellicle membrane to fix the material to the pellicle membrane.

45. The method of claim 44, further comprising: The electron beam or the radiation beam is directed to the pellicle membrane to form a beam spot having a diameter between 0.1 μm and 5 μm on the pellicle membrane.

46. ​​The method of claim 44, further comprising: The electron beam or the radiation beam is used to induce interaction between the material and / or the pellicle membrane or the particles and thereby fix the particles to the pellicle membrane.

47. The method of claim 44, further comprising: The electron beam or the radiation beam is directed such that the electron beam or the radiation beam passes through the pellicle membrane before being incident on the particles.

48. The method of claim 44, further comprising: The particles are fixed to the pellicle membrane during mounting of the pellicle membrane to a reticle, and wherein the electron beam has an energy between 0.5 keV and 5 keV.

49. The method of claim 48, further comprising: The material is provided in a space between the reticle and the pellicle.

50. The method of claim 38 or claim 39, further comprising: The position of the particle on the pellicle membrane is determined.

51. The method of claim 50, further comprising: Particles having a diameter between 0.1 μm and 5 μm are positioned on the pellicle membrane.

52. The method of claim 44, further comprising: By including less than 10 -5 A chamber with a vacuum environment of a pressure of Pa provides the electron beam or the radiation beam to the pellicle diaphragm.

53. The method of claim 44, further comprising: By including more than 10 -5 A compartment having a gaseous environment with a pressure of 0.1 Pa and less than 0.1 Pa provides the electron beam or the radiation beam to the pellicle diaphragm.

54. The method of claim 53, further comprising: At least one of H2, H2O and O2 is provided to the compartment.

55. The method of claim 38 or claim 39, further comprising: After the particles have been fixed to the pellicle membrane, the pellicle membrane is maintained in a clean environment.

56. A method of projecting a patterned radiation beam onto a substrate, the patterned radiation beam passing through a pellicle membrane before being incident on the substrate, wherein: Particles have been fixed to the pellicle membrane using a method as claimed in any one of claims 38 to 55.

57. A pellicle membrane comprising particles which have been fixed to the pellicle membrane using a method as claimed in any one of claims 38 to 55.

58. Use of a system as claimed in any one of claims 1 to 37 for fixing particles to a pellicle membrane for subsequent use in a lithographic apparatus.

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