Method for manufacturing a membrane assembly

Abstract

To provide a method of manufacturing a pellicle membrane and / or a pellicle assembly for EUV lithography.SOLUTION: A method of manufacturing a membrane assembly for EUV lithography is provided, where a layer which forms at least part of a pellicle membrane is provided after one or more etching steps which define a pellicle border holding the pellicle membrane. Also provided is a pellicle substrate, the substrate including a stack having a front face and a back face, where one or more layers on the back face of the stack are selectively removed to define a pellicle border region for holding the pellicle membrane, before the layer forming at least part of a pellicle membrane is provided.SELECTED DRAWING: Figure 4-1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to European Application No. 18214904.7, filed December 20, 2018, the entire contents of which are incorporated herein by reference.

[0002]

[0002] The present invention relates to a method for manufacturing a membrane assembly and to a membrane assembly precursor, which finds particular, but not exclusive, use in connection with an EUV lithography apparatus and an EUV lithography tool. [Background technology]

[0003] A lithographic apparatus is a machine constructed to apply a desired pattern onto a substrate. Lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). A lithographic apparatus can, for example, project a pattern in a patterning device (e.g. a mask) onto a layer of radiation-sensitive material (resist) provided on the substrate.

[0004]

[0004] To project a pattern onto a substrate, a lithographic apparatus may use electromagnetic radiation. The wavelength of this radiation determines the minimum size of features that can be formed on the substrate. Lithographic apparatus using extreme ultraviolet (EUV) radiation having a wavelength in the range of 4-20 nm, e.g., 6.7 nm or 13.5 nm, can be used to form smaller features on a substrate than lithographic apparatus using radiation having a wavelength of, e.g., 193 nm.

[0005] A patterning device (e.g., a mask or reticle) may be used to impart a pattern to a radiation beam in a lithographic apparatus. The radiation is provided through or reflected from the patterning device to form an image on a substrate. Contamination on the surface of the patterning device can cause manufacturing defects on the substrate. A membrane assembly, also called a pellicle, can be provided to protect the patterning device from airborne particles and other forms of contamination.

[0006]

[0006] Pellicles can also be provided to protect optical components other than the patterning device. Pellicles can also be used to provide a passageway for lithographic radiation between regions of the lithographic apparatus that are sealed from each other. Pellicles can also be used as radiation filters, such as spectral purity filters, or as part of a dynamic gas lock in the lithographic apparatus.

[0007]

[0007] The use of pellicles in lithography is well known and established. A pellicle in a lithographic apparatus is a membrane (also called a pellicle membrane) that is located away from the patterning device and that is out of the focal plane of the lithographic apparatus during use. Because the pellicle is out of the focal plane of the lithographic apparatus, contaminant particles that land on the pellicle are out of focus within the lithographic apparatus. Therefore, images of the contaminant particles are not projected onto the substrate. Without the presence of a pellicle, contaminant particles that land on the patterning device would be projected onto the substrate, causing defects in the projected pattern.

[0008]

[0008] The mask assembly can include a pellicle that protects the patterning device (e.g., mask) from particle contamination. The pellicle membrane can be supported by the pellicle assembly or the pellicle boundary that forms the membrane assembly. The pellicle can be attached to the pellicle frame, for example, by gluing or otherwise attaching the pellicle boundary to the pellicle frame. The pellicle frame can be permanently or removably attached to the patterning device. The pellicle membrane is also referred to as a pellicle layer. The pellicle membrane is fabricated starting from a stack including at least a substrate and layers deposited on the substrate.

[0009] It is difficult to manufacture pellicle membranes or pellicle assemblies without the membrane assembly being deformed or damaged during processing, for example, due to the thinness of the membrane. Damage or defects in the membrane assembly can lead to undesirable performance degradation, reduced lifetime, or collapse. It is desirable to provide a method of manufacturing pellicle membranes that provides pellicles with improved yield and / or strength, and that minimizes damage or defects in the membrane assembly.

[0010] Producing a pellicle assembly is also time consuming, and therefore it would be desirable to provide a method for manufacturing a pellicle that has a shorter cycle time than existing methods and / or that can produce a pellicle assembly more quickly.

[0011]

[0011] While this application generally refers to pellicles in the context of lithographic apparatus, and in particular EUV lithographic apparatus, it will be understood that the invention is not limited to only pellicles and lithographic apparatus, and the subject matter of the invention can be used in any other suitable apparatus or environment. In addition, the invention may not be limited to EUV lithography in particular, but can also be used in lithography using radiation of longer or preferably shorter wavelengths than EUV.

[0012]

[0012] Due to the presence of a pellicle in the optical path of an EUV radiation beam, it is necessary for the pellicle to have high EUV transmittance. High EUV transmittance can increase the proportion of incident radiation that passes through the pellicle. Additionally, reducing the amount of EUV radiation absorbed by the pellicle can lower the operating temperature of the pellicle. Because transmittance depends at least in part on the thickness of the pellicle, it is desirable to provide a pellicle that is as thin as possible while still reliably remaining strong enough to withstand the sometimes hostile environment within a lithography apparatus. The desirable feature of a pellicle is that it is as thin as possible, which means that the pellicle membrane itself is susceptible to damage during manufacturing. Small defects or areas of damage in very thin membranes can be detrimental to the membrane's physical properties.

[0013]

[0013] It is desirable to reduce the likelihood that a membrane assembly such as a pellicle will be distorted or damaged during its manufacture, as any flaws in the pellicle can reduce the performance and / or lifetime of the pellicle. Because the manufacturing process for pellicles is time consuming and expensive, it is also desirable to increase the yield of undamaged pellicles during manufacture.

[0014] Etching is a common manufacturing process used to remove portions of material. In multilayer materials, selective etching can remove portions of outer layers so that underlying layers are exposed. A well-defined layer thickness is advantageous because etching typically occurs at a constant rate over time, such that thicker layers take longer to etch than thinner layers. It can also be appreciated that uneven layer thicknesses can result in uneven etching times depending on the layer thickness at each portion of the layer. Over-etching can occur when more material is removed than desired. Over-etching can occur on films with uneven layer thicknesses because thinner portions of the layer can be etched before thicker portions of the layer are completely etched. As a result, depending on which side of the stack is etched, the underlying or overlying layer may be damaged by over-etching. Over-etching in pellicle manufacturing can cause damage to the pellicle film. Therefore, it is desirable to reduce the chance of over-etching. To achieve pellicle membranes and pellicle assemblies with reliable and consistent properties, it is also desirable to develop manufacturing processes to aid in the deposition of layers with well-defined layer thicknesses and / or to remove portions of material in a controlled manner.

[0015]

[0015] The present invention has been devised to address at least some of the problems identified above. Summary of the Invention

[0016]

[0016] According to a first aspect of the present invention, a method for manufacturing a pellicle membrane and / or pellicle assembly for EUV lithography is provided, comprising providing a layer that forms at least a portion of the pellicle membrane after one or more etching steps that define a pellicle boundary that holds the pellicle membrane.

[0017]

[0017] Fabrication of a pellicle involves multiple steps of material deposition and removal using methods such as, but not limited to, chemical vapor deposition, etch masking, and etching. During these processes, the stack is processed and can be manipulated to achieve a desired orientation. At some stages, the stack can be inverted, and at other stages, the stack can be held in place using a clamping mechanism such as a chuck. These chucks apply forces to the layers in the stack during fabrication, which can result in damage. The chuck can also scratch or otherwise damage one or more layers in the stack.

[0018] In other methods for manufacturing pellicle membranes and membrane assemblies for EUV lithography, the layers that will ultimately form the pellicle membrane are deposited at an early stage. This means that the pellicle membrane layers are deposited or otherwise provided on a clean surface that is substantially free of contaminants or defects. Following the deposition of the layers that will ultimately form the pellicle membrane, further deposition, protection, and etching steps are performed to form the final pellicle membrane or pellicle assembly. However, during further processing steps, the layers that will form the final pellicle membrane may be damaged. In other manufacturing methods, the final pellicle membrane layers are covered by other layers until later in the process. Therefore, any defects or damage in the final pellicle membrane are not covered until multiple complex and time-consuming steps are performed. Therefore, nearly the entire manufacturing process must be performed before the defective pellicle membrane is identified and discarded. The time required from identifying a fault to creating a new pellicle assembly can be referred to as the learning time. A method according to the present invention has the advantage of reducing the learning time.

[0019] In the method according to the first aspect of the present invention, the layers that will ultimately form the pellicle membrane are provided at a later process stage than in other methods. In the present invention, the final pellicle membrane layer is deposited only after a specific etching step has been performed. The final pellicle assembly includes a pellicle boundary that holds the pellicle membrane. The pellicle boundary can be mechanically or chemically attached to the pellicle frame. The pellicle frame can be removably or permanently attached to the patterning device MA. By pellicle membrane, it is understood to refer to a layer of material that spans the pellicle boundary and through which EUV radiation passes when used as a pellicle. The layer may also be referred to as a pellicle layer, a pellicle core layer, or a pellicle membrane. The material that will form the pellicle membrane is provided after an etching step that defines the pellicle boundary has been performed. It should be understood that this does not require the pellicle boundary to be formed, but rather a layer that protects a portion of a layer, such as a planar substrate, that will ultimately become the pellicle boundary from subsequent etching steps. For example, if the stack includes a silicon planar substrate that forms the final pellicle boundary that holds the pellicle membrane, the etching step that defines the final pellicle boundary may include etching one or more layers that serve to protect from etching the portion of the planar substrate that will ultimately form the pellicle boundary.

[0020]

[0020] Surprisingly, it has been found that it is possible to provide a layer or membrane that will ultimately form at least a portion of the final pellicle membrane after several etching steps have been performed without adversely affecting the quality of the final pellicle membrane. In addition, the method of the present invention can also reduce the time required to produce a pellicle assembly, in that it is possible to perform some of the steps required to manufacture a pellicle assembly or pellicle membrane starting from the stack before the layer or membrane that will become the final pellicle membrane is provided. In other manufacturing methods that require depositing a pellicle membrane at an early stage, if a membrane assembly having a specific pellicle membrane is required, it is necessary to start forming the pellicle membrane from the beginning of the process. In contrast, the method of the present invention can effectively start forming portions of the pellicle membrane layer throughout the entire process, thereby saving time.

[0021] The method can include providing a stack having a front surface and a back surface. The stack can include a substrate with one or more layers. For example, the stack can include a planar substrate such as a silicon wafer or a silicon-on-insulator (SOI) wafer.

[0022]

[0022] The method may also include providing a protective layer on the front side of the stack. The protective layer may be any suitable material capable of protecting the underlying portion of the stack from a subsequent etching process. The present invention is not particularly limited by the nature of the protective layer.

[0023] The method can also include selectively removing one or more portions from the backside of the stack. These portions can serve to define the pellicle boundary of the final pellicle assembly. The selective removal can be performed by any suitable technique, and the present invention is not particularly limited by the technique used. During fabrication processes such as resist deposition, patterning, and etching, the stack must be held in place or moved using a clamping mechanism, also known as a chuck. In alternative fabrication methods, these chucks can apply forces on the pellicle layers during fabrication, potentially resulting in damage to the pellicle. An advantage of the present invention is that the selective removal of at least a portion of the backside of the stack is completed prior to the deposition of at least one membrane layer, ensuring that the chuck does not apply forces to the membrane layer at this point. This reduces the likelihood of the pellicle membrane or layers being damaged during processing.

[0024]

[0024] The method may also include removing at least a portion of the protective layer from the front surface of the stack. Once the back surface of the stack has been etched, the protective layer on the front surface of the stack can be removed, as the front surface of the stack no longer requires protection from etching. Removal of the protective layer can be achieved by any suitable technique, and the present invention is not particularly limited to the technique used.

[0025]

[0025] The method can also include providing a layer that forms at least a portion of the pellicle membrane on the front surface of the stack. While it is understood that a protective layer is preferably provided on the front surface of the stack to protect the front surface of the stack during the etching step, this is not required and it may be possible to etch the back surface of the stack without providing any protective layer on the front surface of the stack. Because etching of the back surface of the stack is completed prior to providing the layer that forms at least a portion of the pellicle membrane, the risk of damaging such pellicle layer is reduced. The present invention is not particularly limited to how the pellicle layer is provided, and any suitable technique, such as chemical vapor deposition, can be used.

[0026] The method may further include selectively removing one or more portions of the stack to form a pellicle assembly. Thus, the pellicle assembly may include a pellicle membrane comprising at least one membrane layer and a pellicle boundary that holds the pellicle membrane. One or more portions from the stack may be removed by any suitable technique, and the invention is not particularly limited by the technique used. For example, etching may be used to remove one or more portions. The method may include one or more steps for selectively removing one or more portions of the stack to form the pellicle assembly.

[0027] The method can further include providing at least one emissive layer on the front surface of the stack, such that the pellicle assembly comprises a membrane comprising at least one membrane layer and at least one emissive layer. The emissive layer is preferably provided after the at least one membrane layer is provided. The emissive layer can be provided below the at least one membrane layer, or both above and below the at least one membrane layer. Thus, the emissive layer can be provided on the front, back, or both surfaces of the pellicle membrane. The emissive layer can serve to increase the thermal emissivity of the pellicle assembly. Increasing the emissivity of the pellicle assembly can reduce the operating temperature of the pellicle, which can increase the lifetime of the pellicle. Additionally, the emissive layer can protect the membrane layer from the atmosphere within the lithographic apparatus. For example, if the pellicle layer contains carbon, low-pressure hydrogen within the lithographic apparatus can be ionized by radiation, and hydrogen radicals can attack the carbon and weaken the pellicle over time. Thus, the emissive layer can also protect the pellicle membrane layer. If an ejection layer is provided on the back surface of at least one membrane layer, it may also be provided on the inner surface of the boundary. Alternatively or additionally, an ejection layer may also be provided on the bottom of the boundary, i.e., on the "legs" of the boundary. While it may be possible to provide an ejection layer only on the membrane layer, it may be more convenient to simply coat the bottom surface of the assembly with an ejection layer.

[0028] The method may further include providing at least one capping layer on the front surface of the stack, preferably comprising silicon dioxide and / or silicon nitride. Other capping layers may also be used. The capping layer may be provided by any suitable technique, and the present invention is not particularly limited to the technique used. In one example, tetraethyl orthosilicate (TEOS) may be provided and then converted to silicon dioxide using known techniques. The capping layer may serve to protect the pellicle core layer of the stack. The capping layer may have better compatibility with the overlying layer, thereby creating a stronger bond between the layers in the stack. Thin layers of silicon dioxide are easily grown at known layer thicknesses, as is known in the art. A layer of known thickness is advantageous for the etching process because it reduces the risk of over-etching in some areas of the layer due to uneven layer thickness. Depositing a thin layer of silicon dioxide as a capping layer can subsequently improve the reliability of the etching and reduce the chance of damage to the membrane.

[0029] The method can include providing a resist on the stack and patterning the resist prior to selectively removing one or more portions from the backside of the stack. The present invention is not particularly limited by the nature of the resist, and any suitable resist can be used. This step provides a mask, allowing for the definition of a pattern on the surface of the stack, e.g., the definition of a pellicle boundary on the stack. The resist can be patterned in such a way as to define the final pellicle boundary of the final pellicle assembly. The resist serves to protect the underlying layers from etching. Thus, the patterning of the resist serves to define the areas of the stack that will be removed by a subsequent etching step. The etchant can be a chemical etchant, e.g., phosphoric acid (H3PO4) and / or hydrofluoric acid (HF). After etching, the resulting pellicle membrane can include, e.g., a MoSiNx pellicle core layer with a native oxide layer on one or both of its surfaces. Herein, x refers to the variability of nitrogen in the material composition, and the variability can equivalently be Mo. t Si p N z Alternatively, after etching and metal deposition, the stack can be formed (e.g., in a cavity defined by the pellicle boundary) with, for example, a SiN / Ox / pSi pellicle core layer / low stress nitride (LSN) on the front side of the stack and a cap of Mo / Ru on the back side.

[0030]

[0030] The method may further include selectively removing one or more portions from the back surface of the stack to form a pellicle assembly, and / or etching at least a portion of the stack during the step of selectively removing one or more portions of the stack.

[0031] The stack can comprise a planar substrate and preferably at least one sacrificial layer. The planar substrate can be a wafer. The planar substrate can form a pellicle core layer of the stack. Preferably, the wafer comprises silicon. Silicon is a well-characterized material commonly used in the field. It will be understood that other suitable materials can be used and that the present invention is not limited to silicon-based substrates (i.e., silicon-containing substrates such as pSi, SiC, MoSi2, or MoSiNx). For example, the substrate can also be carbon-based, such as a graphene pellicle core layer or a carbon nanotube pellicle core layer for the stack.

[0032]

[0032] The method can further include depositing one or more additional sacrificial layers, for example, during the deposition of at least one membrane layer. This is preferably followed by selective removal of one or more portions of the additional sacrificial layer. The sacrificial layer can include silicon nitride and / or silicon dioxide. Depending on the material of the pellicle core layer, other materials can also be used as sacrificial layers.

[0033]

[0033] The at least one membrane layer may comprise at least one silicon layer, preferably formed by crystallizing at least one amorphous silicon layer. The membrane layer may comprise pSi. Silicon has good EUV transmittance and is therefore a suitable material for the at least one membrane layer. The at least one membrane layer may be coated with one or more materials that serve to provide additional chemical or thermal resistance and / or increase the emissivity of the membrane assembly.

[0034]

[0034] The protective layer may comprise a cross-linked polymer. The polymer may be a poly(p-xylylene) polymer. The polymer may be a Parylene or ProTek® type material. Alternatively or additionally, it may comprise a resist, such as KMPR®.

[0035] At least one membrane layer can be disposed between the at least one emissive layer and the front surface of the stack. It will be appreciated that in some embodiments, an emissive layer can be provided on one or both sides of the membrane layer. In one embodiment, the membrane layer does not have an emissive layer or other capping layer, and is formed solely by at least one pellicle core layer. For example, the pellicle is formed solely by a MoSiNx pellicle core layer.

[0036]

[0036] At least one emissive layer can be a metal. At least one emissive layer can include boron or a boron-containing material, or Zr or a Zr-containing material. Boron-containing materials, such as metal alloys of boron, such as zirconium boride (ZrB2), can increase the emissivity of the pellicle and can also protect the membrane layer.

[0037]

[0037] Preferably, the at least one emissive layer can further include three metal emissive layers. In this embodiment, the three emissive layers include a zirconium layer disposed between two boron layers, the zirconium layer including zirconium or a zirconium-containing material, and the boron layer including boron or a boron-containing material. In another alternative, the emissive layer can include a layer of B, Zr, Ru, or Mo. Other emissive layers can also be used.

[0038] At least one capping layer has a capping layer thickness, and at least one membrane layer has a membrane layer thickness, preferably the capping layer thickness being less than the membrane layer thickness. For example, the capping layer can have a thickness of 0.5 to 10 nm, preferably 1 to 5 nm. In this manner, the membrane layer provides the majority of the physical strength of the pellicle membrane within the pellicle assembly.

[0039]

[0039] The method may further include selectively removing at least a portion of the at least one capping layer after selectively removing one or more portions of the stack to form the pellicle assembly.

[0040] At least one sacrificial layer may further be provided for the at least one membrane layer and / or the at least one capping layer and / or the at least one release layer. The method may further comprise providing an additional sacrificial layer, for example before, during or after deposition of the at least one membrane layer. This is preferably followed by selective removal of one or more portions of the additional sacrificial layer.

[0041]

[0041] According to a second aspect of the present invention, a pellicle substrate is provided, the substrate comprising a stack having a front surface and a back surface, and one or more layers on the back surface of the stack are selectively removed to define a pellicle boundary region for holding the pellicle membrane before a layer forming at least a portion of the pellicle membrane is provided.

[0042]

[0042] The present invention can provide partially processed pellicle substrates. Because processing a pellicle substrate can take several weeks before a partially processed pellicle substrate can be provided, such substrates can be held in storage until needed, reducing the time between orders for membrane assemblies with specific pellicle membranes. During manufacturing, defects can be identified in the pellicle layer, in which case the pellicle must be scrapped and a new pellicle assembly must be fabricated. According to the above aspects of the present invention, the manufacturing process can continue from the provision of the pellicle substrate rather than from the beginning, thereby reducing the learning curve for the manufacturing process.

[0043]

[0043] In one embodiment, the pellicle substrate may not include a layer for forming at least a portion of the pellicle membrane. In such an embodiment, the pellicle substrate is processed so that the final pellicle boundary is defined, but the material that will form the pellicle membrane is not present. In this way, different pellicle membrane materials can be provided and investigated or used more quickly than before.

[0044] In another embodiment, the pellicle substrate includes materials for forming the final pellicle membrane, but this is provided after processing steps that define the final pellicle boundary region have been performed.

[0045]

[0045] Preferably, the pellicle substrate has at least one protective layer on its front surface, and preferably the at least one protective layer comprises a cross-linked polymer, preferably a poly(p-xylylene) polymer, preferably a Parylene or ProTEK (registered trademark) type material, or a resist such as KMPR (trademark).

[0046]

[0046] The stack may comprise a planar substrate and preferably at least one sacrificial layer, preferably the planar substrate is a wafer, optionally a silicon wafer or an SOI wafer, and preferably the at least one sacrificial layer comprises silicon nitride.

[0047]

[0047] According to a further aspect of the present invention, there is provided a pellicle assembly manufactured according to a method including any of the methods described above.

[0048]

[0048] In one embodiment, the method according to the present invention results in the pellicle membrane, after etching, comprising a MoSiNx core layer having no further functional cap layer, or a MoSiNx core layer having at least one surface covered with a native oxide layer.

[0049]

[0049] In one embodiment, the method according to the present invention results in that after etching and metal deposition, a pellicle stack is formed with SiN / Ox on the front side, a pSi pellicle core layer, a low stress nitride (LSN) layer, and a cap layer of Ru on Mo deposited on the back side of the stack.

[0050]

[0050] In a further aspect of the present invention, the pellicle substrate comprises a pellicle core layer which can be selected from a silicon-based material such as pSi, SiC, MoSi2, or MoSiNx, or a carbon-based material such as a graphene film or a film formed by carbon nanotubes.

[0051] In yet another aspect of the invention, the pellicle stack comprises layers of SiO / MoSiNx / MoSi2 or layers of SiON / MoSiNx / SiON, although combinations of only two of these layers are also contemplated herein.

[0052]

[0052] While it is understood that the final pellicle provided by the present invention is fundamentally the same as a pellicle assembly manufactured using other methods, providing the pellicle layer later in the process has many advantages, as discussed above, that were not previously realized.

[0053] It will be understood that any of the above-discussed aspects of the invention may, where appropriate, be combined with one or more other aspects of the invention. Furthermore, an optional feature described with respect to one of the aspects of the invention may, where appropriate, be an optional feature of one of the other aspects of the invention.

[0054]

[0054] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which: [Brief explanation of the drawings]

[0055] [Figure 1]FIG. 1 illustrates a lithography system comprising a lithography apparatus including a pellicle assembly. [Figure 2] FIG. 1 illustrates a pellicle assembly. [Figure 3] 1A-1C show stages in the manufacture of a pellicle assembly according to a method other than the method according to the present invention, using a cross section of the stack for illustration purposes. [Figure 4] 1A-1C illustrate stages in the manufacture of a pellicle assembly in accordance with one embodiment of the present invention, using a cross section of a stack for illustration purposes. [Figure 5] 1A-1C illustrate an embodiment of the present invention following the deposition of multiple membrane layers. [Figure 6] 1A-1C illustrate an embodiment of the present invention showing the final pellicle assembly before and after the final etch. [Figure 7] 1A-1C illustrate another embodiment of the present invention following the deposition of multiple membrane layers. [Figure 8] 1A-1C illustrate another embodiment of the present invention showing the final pellicle assembly before and after the final etch. [Figure 9] FIG. 1 illustrates an embodiment of a pellicle assembly in which an emissive layer is provided on the back surface of the assembly.

[0056] The features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the drawings, in which like reference numerals identify corresponding elements throughout and in which like reference numerals generally indicate identical, functionally similar, and / or structurally similar elements. DETAILED DESCRIPTION OF THE INVENTION

[0057] 1 shows a lithographic system including a pellicle 15 (also called a pellicle assembly) manufactured according to the method of the first aspect of the present invention. The lithographic system comprises a radiation source SO and a lithographic apparatus LA. The radiation source SO is configured to generate a beam of extreme ultraviolet (EUV) radiation 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.

[0058] The illumination system IL is configured to condition the radiation beam B before it is incident on the patterning device MA. The projection system is configured to project the radiation beam (patterned by the mask MA) onto the substrate W. The substrate W may include a pre-formed pattern. In this case, the lithographic apparatus aligns the patterned radiation beam B with the pre-formed pattern on the substrate W. In this embodiment, a pellicle assembly 15 is shown in the path of the radiation to protect the patterning device MA. It will be appreciated that the pellicle assembly 15 can be positioned in any required position and can be used to protect any mirror in the lithographic apparatus.

[0059] The source SO, the illumination system IL, and the projection system PS may all be constructed and adjusted so as to be isolated from the external environment. A gas (e.g., hydrogen) at a pressure below atmospheric pressure may be provided in the source SO. A vacuum may be provided in the illumination system IL and / or the projection system PS. A small amount of gas (e.g., hydrogen) at a pressure well below atmospheric pressure may be provided in the illumination system IL and / or the projection system PS.

[0060]

[0059] The source SO may take any form, for example being of a type that may be referred to as a laser-produced plasma (LPP) source. Alternatively, the source SO may comprise one or more free electron lasers. The one or more free electron lasers may be configured to emit EUV radiation that may be provided to one or more lithographic apparatus.

[0061]

[0060] The radiation beam B passes from the radiation source SO into an illumination system IL configured to condition the radiation beam. The illumination system IL may include a facetted field mirror device 10 and a facetted pupil mirror device 11. Together the facetted field mirror device 10 and the facetted pupil mirror device 11 provide the radiation beam B with a desired cross-sectional shape and a desired angular distribution. The radiation beam B passes from the illumination system IL and is incident on a patterning device MA, which is held by a support structure MT. The patterning device MA is protected by a pellicle layer 19, which is held in place by a pellicle boundary 17. The pellicle layer 19 and the pellicle boundary 17 together form a pellicle assembly 15. The patterning device MA (which may be, for example, a mask) reflects and pattern the radiation beam B. The illumination system IL may include other mirrors or devices in addition to or instead of the facetted field mirror device 10 and the facetted pupil mirror device 11.

[0062] Following reflection from the patterning device MA, the patterned radiation beam B enters a projection system PS. The projection system comprises a number of mirrors 13, 14 configured to project the radiation beam B onto a substrate W held by a substrate table WT. The projection system PS applies a demagnification factor to the radiation beam to form an image with smaller features than corresponding features on the patterning device MA. For example, a demagnification factor of 4 can be applied. In Figure 1, the projection system PS has two mirrors 13, 14, but the projection system may include any number of mirrors (for example, six mirrors).

[0063] The radiation source SO shown in Figure 1 may include components not shown. For example, a spectral filter may be provided within the radiation source. The spectral filter may be substantially transparent to EUV radiation but substantially blocking to other wavelengths of radiation, such as infrared radiation.

[0064] As briefly described above, pellicle assembly 15 includes a pellicle layer 19 provided in proximity to patterning device MA. Pellicle layer 19 is provided in the path of radiation beam B such that radiation beam B passes through pellicle layer 19 both when approaching patterning device MA from illumination system IL and when reflected by patterning device MA towards projection system PS. Pellicle layer 19 comprises a thin film that is substantially transparent to EUV radiation (although it absorbs small amounts of EUV radiation). Pellicle layer 19 acts to protect patterning device MA from particle contamination. Pellicle layer 19 may be referred to herein as an EUV-transparent pellicle.

[0065] While efforts can be made to maintain a clean environment inside the lithographic apparatus LA, particles may still be present inside the lithographic apparatus LA. In the absence of the pellicle layer 19, particles could deposit on the patterning device MA. Particles on the patterning device MA could adversely affect the pattern imparted to the radiation beam B, and therefore the pattern transferred to the substrate W. The pellicle layer 19 provides a barrier between the patterning device MA and the environment within the lithographic apparatus LA to prevent particles from depositing on the patterning device MA.

[0066] In use, the pellicle layer 19 is positioned a sufficient distance from the patterning device MA such that any particles incident on the surface of the pellicle layer 19 are not in the focal plane of the radiation beam B. This separation between the pellicle layer 19 and the patterning device MA acts to reduce the extent to which any particles on the surface of the pellicle layer 19 will impart a pattern to the radiation beam B. It will be appreciated that if a particle is present in the radiation beam B but is located not in the focal plane of the radiation beam B (i.e. not at the surface of the patterning device MA), no image of the particle will be focused at the surface of the substrate W. In some embodiments, the separation between the pellicle layer 19 and the patterning device MA may be, for example, between 2 mm and 3 mm (e.g., about 2.5 mm). In some embodiments, the separation between the pellicle layer 19 and the patterning device is adjustable.

[0067] In one embodiment, the pellicle assembly 15 is for a dynamic gas lock. In this case, the membrane assembly 15 functions as a filter for filtering DUV radiation. Additionally or alternatively, in one embodiment, the membrane assembly 15 is a pellicle for a patterning device MA for EUV lithography. The membrane assembly 15 of the present invention can be used for a dynamic gas lock, a pellicle, or for another purpose. In one embodiment, the membrane assembly 15 includes a membrane formed from at least one membrane layer configured to transmit at least 90% of incident EUV radiation. To ensure maximum EUV transmission and minimal impact on imaging performance, the membrane is preferably supported only at its boundaries.

[0068] FIG. 2 is a schematic diagram showing a cross section of the pellicle assembly 15 and the patterning device MA in more detail. The patterning device MA has a patterned surface 24. A pellicle boundary 17 supports the pellicle layer 19 around the periphery of the pellicle layer 19. The pellicle boundary 17 can be attached to a pellicle frame 22. The pellicle frame 22 can include an attachment mechanism (not shown) configured to removably attach the pellicle frame 22 to the patterning device MA (i.e., to attach the pellicle frame 22 to and detach it from the patterning device MA). The attachment mechanism is configured to engage with an attachment feature (not shown) provided on the patterning device MA. The attachment feature can be, for example, a protrusion extending from the patterning device MA. The attachment mechanism can include, for example, a locking member that engages the protrusion and secures the pellicle frame 22 to the patterning device MA. Multiple attachment mechanisms and associated attachment features can be provided. The attachment mechanisms may be distributed around the periphery of the pellicle frame 22 (e.g., two on one side of the pellicle frame and two on the opposite side of the pellicle frame), and the associated attachment features may be distributed around the periphery of the patterning device MA.

[0069] 2, a contaminant particle 26 is shown schematically. The contaminant particle 26 is incident on the pellicle layer 19 and is retained by the pellicle layer 19. The pellicle layer 19 retains the contaminant particle far enough from the patterned surface 24 of the mask MA so that it is not imaged onto the substrate by the lithographic apparatus LA.

[0070]

[0069] A pellicle assembly according to one embodiment of the present invention allows a mask pattern to be provided (on a patterning device) that remains substantially defect-free during use (the mask pattern is protected from contamination by the pellicle).

[0071] The pellicle assembly 15 can be constructed by depositing a pellicle layer 19 (which can be, for example, a pellicle core layer made of polysilicon (pSi) or MoSiNx) directly on top (front side) of a substrate to provide a pellicle boundary 17. For example, the stack can be SiO / MoSiNx / MoSi2 or SiON / MoSiNx / SiON. The substrate can be, for example, a silicon wafer or an SOI wafer. After deposition of the pellicle layer 19 film, the substrate can be selectively back-etched (i.e., etched on the back side) to remove the center of the substrate and leave only the outer periphery to form a pellicle boundary 17 for supporting the pellicle layer 19. The fabrication process is hereby discussed with reference to the following drawings:

[0072] 3 shows, using a cross section of a stack for illustration purposes, a schematic representation of the stages in the manufacture of a pellicle assembly according to an alternative manufacturing process that differs from the method of the present invention. This method is included to provide a comparison with the method of the present invention.

[0073]

[0072] A stack 100 is provided, comprising a planar substrate 30 and a first optional sacrificial layer 31. The planar substrate 30 is disposed in an internal region of the stack 100, and the first sacrificial layer 31 is disposed in an external region of the stack 100. Thus, the first sacrificial layer 31 preferably substantially surrounds the planar substrate 30. The planar substrate 30 can be, for example, a silicon wafer or an SOI wafer. The planar substrate 30 has a shape such as a square, a circle, or a rectangle. The shape of the planar substrate 30 is not particularly limited, but is most likely a circle, which is the most commonly usable shape. The size of the planar substrate 30 is not particularly limited.

[0074] Although the first sacrificial layer 31 is shown as completely surrounding the planar substrate 30, in some embodiments, the first sacrificial layer 31 can only partially surround the planar substrate 30. In the illustrated embodiment, a single sacrificial layer 31 is shown, but it will be understood that there can be more sacrificial layers 31. The first sacrificial layer can include, for example, silicon oxide, silicon nitride, tetraethyl orthosilicate (TEOS), chemical oxide, or thermal oxide.

[0075] The stack 100 has a front surface and a back surface (also referred to as the back surface). The front surface is defined as the surface that is proximal to the pellicle layer later in fabrication. The front and back surfaces may be designated prior to deposition of the pellicle layer. These terms are used to better understand the invention and to more clearly define the process steps. However, the method is also intended to cover the case where the stack is inverted or otherwise rotated.

[0076] To define the stack 101, at least one pellicle layer 32 is disposed on the first sacrificial layer 31. Again, the pellicle layer 32 is shown surrounding the first sacrificial layer 31, although in alternative embodiments the membrane layer 32 may only partially surround the first sacrificial layer 31 or may be deposited on one side of the stack 100. The pellicle layer 32 may also be referred to as a pellicle film, membrane layer, pellicle core layer, or membrane film.

[0077] Although a single pellicle layer 32 is shown, it will be understood that the pellicle layer 32 may include multiple layers. The pellicle layer will include at least one pellicle core layer. The pellicle core layer may comprise, for example, polysilicon (pSi) or MoSiNx. The pellicle core layer has two primary purposes: to provide mechanical strength to the pellicle layer 32 and to allow transmission of radiation, such as EUV. The pellicle layer 32 may also include at least one additional sacrificial layer (not shown).

[0078]

[0077] The stack 101 may also include several other layers of material deposited on the planar substrate 30, the layers having various protective functions during the manufacturing process of the pellicle assembly 15 or to enhance the characteristics of the pellicle assembly 15, such as chemical / environmental resistance and / or improved (thermo)mechanical strength and / or reduced imaging effects (e.g., by reducing pellicle reflection of EUV radiation or enhancing reflection of undesirable out-of-band radiation such as DUV or IR radiation).

[0079] The stack 102 shows a step in which a first resist 33 is deposited. The first resist 33 can be a positive or negative resist, and the manner in which the resist is used is not particularly limited. The first resist 33 is patterned to define the portions of the stack 103 that will be etched in a subsequent etching step. The first resist 33 is sometimes called an etch mask.

[0080]

[0079] The stack 102 can then be etched by any suitable etching means to remove the portion of the pellicle layer 32 that is not protected by the resist 33, resulting in the stack 103. This etching step may also remove a portion of the sacrificial layer 31, or any of the additional layers mentioned above, if so designed.

[0081] A protective layer 34 is then applied to the front side of the stack 104 to protect the surfaces at the front of the stack 104. In particular, the protective layer can protect layers, particularly the pellicle layer 32, at the front side of the stack 104 from subsequent etching steps and / or physical contact. The protective layer 34 can comprise a cross-linked poly(p-xylylene) polymer, such as, preferably, a Parylene or ProTEK®-type material, or can be a resist, such as a KMPR® and / or TEOS layer. The protective layer 34 is applied as a continuous layer that is substantially hole-free, providing a layer that is impermeable to etchants. The protective layer 34 is preferably not added to the rear side (i.e., back side) of the stack 104, so that the etchant can access the planar substrate 30 and any sacrificial layer 31 through the rear side of the stack 104. An optional protective layer 34 is applied to the front side of the stack to protect the front surface of the stack. This allows for maintaining a clean deposition surface during subsequent processing steps prior to deposition of pellicle layer 32. It will be appreciated that protective layer 34 may be omitted if etching the back side of the stack does not pose a risk of damaging the front side of the stack, although protective layer 34 is still preferred.

[0082] The stack 104 is then inverted and a second resist 35 is deposited on the back side of the stack 105. The second resist 35 can be a positive or negative resist, and the manner in which the resist is used is not particularly limited. The second resist 35 is patterned to define the portions of the stack 105 that will be etched in a subsequent etching step. The second resist 35 is sometimes referred to as an etch mask. After the pellicle layer has been applied, it is at this stage in the process that the final pellicle boundary area is defined.

[0083] In this regard, during the manufacturing process, contacts may occur between the stack 105 and a chuck (not shown). The chuck may include, for example, edge contacts, lift pins, end effectors, and center wheel contacts used to hold, move, and align the stack. These contacts may occur on the front side of the stack 105 where the pellicle layer 32 resides, posing a high risk of damaging the pellicle layer 32.

[0084]

[0083] The present invention has the advantage of mitigating this risk of damage by providing a different manufacturing process, which is described in more detail below with reference to FIG.

[0085] 4 shows a schematic diagram of the manufacturing stages of a pellicle assembly according to one embodiment of the present invention. A cross section of a stack is used for illustration purposes. The manufacturing stages are discussed below. Some of the steps and materials correspond to those described above and will not be described in detail, but can be considered equivalent.

[0086] A stack 200 is provided, comprising a planar substrate 30 and a first sacrificial layer 31. An optional protective layer 34 is applied to the front side of the stack 201 to protect the surface at the front of the stack 201. This makes it possible to maintain a clean deposition surface during subsequent processing steps prior to the deposition of the pellicle layer 32. It will be appreciated that the protective layer 34 may be omitted if etching the back side of the stack does not pose a risk of damaging the front side of the stack. Even in this case, the protective layer 34 is preferred.

[0087] The stack 201 is inverted, and a first resist 35 is applied to the rear (i.e., back) side of the stack 202. Inverting the stack 201 is optional; it may be possible to perform the process without inversion. The resist 35 is patterned to define the portions of the stack 202 that will be etched in a subsequent etching step and that serve to define the pellicle boundary of the final pellicle assembly. The stack 202 is then etched by any suitable etching means to remove the portions of the first sacrificial layer 31 that are not protected by the resist 35. At this point, the pellicle boundary of the final pellicle assembly has been defined, and the material that will provide the final pellicle membrane has yet to be applied. At this point in the manufacturing process, contacts may occur between the stack 202 and the chuck. These contacts may occur on the front side of the stack 202, where the pellicle layer 32 is not present. The present invention therefore mitigates the high risk of damage to the pellicle layer 32.

[0088] The resulting stack 203 can then be used to deposit subsequent pellicle layers and thus manufacture pellicle assemblies. The resulting stack 203 is sometimes referred to as a pellicle substrate 203. The pellicle substrate 203 can be retained for a significant period of time prior to further manufacturing steps without degradation or contamination of the front surface of the stack 203. Thus, if a pellicle layer is damaged in a further manufacturing step, manufacturing can resume from stack 203 (rather than stack 100 in an alternative manufacturing process), reducing the process learning time.

[0089] Following removal of the protective layer 34, at least one pellicle layer 32 is provided on the stack 203 to define a new stack 204. Again, the pellicle layer 32 is shown surrounding the entire stack 203, although in alternative embodiments, the membrane layer 32 may only partially surround the stack 203 or may be deposited on one side of the stack 203. A pellicle layer is also referred to as a pellicle film, a membrane layer, or a membrane film.

[0090]

[0089] Although a single pellicle layer 32 is shown, it will be understood that there can be more pellicle layers 32. The pellicle layers can include at least one pellicle core layer. The pellicle core layer can comprise, for example, polysilicon (pSi) or MoSiNx. The pellicle core layer has two primary purposes: to provide mechanical strength to the pellicle layer 32 and to allow transmission of radiation, such as EUV.

[0091] In alternative embodiments, pellicle layer 32 can include at least one additional layer having various protective functions during the manufacturing process of pellicle assembly 15 or to enhance the characteristics of pellicle assembly 15, such as chemical / environmental resistance (e.g., by reducing pellicle reflection), improved (thermo)mechanical strength, reduced imaging effects, and / or increased emissivity. For example, at least one additional layer, such as a boron or boron-containing layer, may already be provided before the pellicle layer is provided. Some additional embodiments are described in detail below and in FIGS. 5-8.

[0092] Following deposition of at least one pellicle layer 32, the stack 204 can be further processed to remove portions of material to form the final pellicle assembly 15. Selective removal of portions of material can remove the pellicle assembly 15 from surrounding portions of the planar substrate 30 and sacrificial layer 31. The areas to be removed were defined using resist 35. The selectively removed portions of material further define the pellicle layer 19 and pellicle boundary 17. Further processing steps are not particularly relevant to the present invention and therefore will not be described in detail herein. Conventional processing steps include, but are not limited to, the application of additional resist and / or masking layers, and the addition and removal of protective layers.

[0093] Further processing steps can be performed after removing membrane assembly 15 from planar substrate 30 and surrounding portions of sacrificial layer 31. For example, pellicle layer 32 of pellicle assembly 15 can include additional sacrificial or capping layers, as detailed above. These additional layers can be removed or manipulated in further processing steps.

[0094] 5 and 6 illustrate a preferred embodiment of the present invention, further defining the composition of pellicle layer 32. It is a feature of the present invention that by depositing pellicle layer 32 later in the manufacturing process, a wider range of materials and layer thicknesses can be used. This is due in part to the selective removal of one or more portions from the backside of the stack before depositing pellicle layer 32, thereby reducing the risk of damage to the pellicle layer.

[0095] In this embodiment, as shown most clearly in FIG. 5 , a pellicle layer 32 is deposited. In this embodiment, the pellicle layer comprises a pellicle core layer 51, two capping films 52, and a spacing film 53. The pellicle core layer 51 is disposed between the two capping films 52 to form a capped pellicle layer 55. The pellicle core layer is also referred to as a pellicle film or a core film. The spacing film 53 is disposed between the capped pellicle layer 55 and the sacrificial layer 31. Preferably, an optional additional spacing layer 56 is provided between the spacing film 53 and the first capping layer 52. This additional optional spacing layer 56 can act as an etch stop in a subsequent etching step.

[0096]

[0095] The pellicle core layer 51 can comprise, for example, polysilicon (pSi), which has high transmittance in EUV and also provides strength to the pellicle assembly. The spacer 53 can be made, for example, from silicon oxide, preferably thermal oxide. The spacer 53 defines a surface for receiving the further pellicle layers 51, 52. The additional spacer layer 56 can comprise any material having etch selectivity relative to silicon oxide, such as silicon or silicon nitride.

[0097]

[0096] The capping layer 52 may preferably consist of silicon oxide, for example silicon dioxide (SiO2). The capping layer 52 is preferably a thin film compared to the thickness of the pellicle core layer. Thin films of SiO2 can be easily manufactured with a well-defined layer thickness. A well-defined layer thickness is advantageous in pellicle manufacturing, since an uneven layer thickness can lead to excessive etching and thus damage to the pellicle core layer 51. Therefore, it is desirable to provide a layer with a well-defined layer thickness.

[0098] 6A, following removal of the pellicle assembly 15 from the surrounding portion of material, the pellicle layer comprises multiple layers. In this preferred embodiment, the pellicle core layer 51 is preferably comprised of silicon, such as polysilicon (pSi) or MoSiNx, and the capping layer 52 is comprised of silicon oxide, such as silicon dioxide (SiO2).

[0099] 6B, it is then desirable to remove the capping layer 52, leaving only the pellicle core layer 51. This increases the transmittance of the pellicle assembly 15. The final pellicle assembly comprises the pellicle core layer 51 supported on the pellicle boundary 17. The pellicle boundary 17 includes a sacrificial layer 31 disposed between the planar substrate 30 and a spacer 53, which is disposed between the sacrificial layer 31 and an optional additional spacer 56, which is continuous with the capping layer 52. Before adjoining the pellicle core layer 51, the pellicle boundary 17 preferably comprises an ordered layer made up of a silicon layer, a silicon dioxide layer, a thermal oxide layer, an optional silicon layer, and a silicon dioxide layer.

[0100]

[0099] Removal of capping layer 52 can be accomplished using a number of methods, but is preferably accomplished by etching.

[0101] [000100] Figures 7 and 8 show a preferred embodiment of the invention, further defining the composition of the pellicle layer 32. Many of the features correspond to those previously described and therefore will not be described in more detail.

[0102] In this embodiment, as shown most clearly in FIG. 7 , a pellicle layer 32 is provided on the stack. The pellicle layer 32 is deposited on a first sacrificial layer 31. In this embodiment, the pellicle layer 32 comprises a pellicle core layer 51, a first capping film 52a, at least one capping film 52b, and a spacing film 53. Preferably, the pellicle layer 32 can further comprise a third capping film 52c and a fourth capping film 52d, with the second, third, and fourth capping films 52b, 52c, and 52d comprising an upper capping layer 52e, also referred to as an emission film. The pellicle core layer 51 is disposed between the first capping film 52a and the emission film 52e to form a capped pellicle layer 55. The spacing film 53 is disposed between the capped pellicle layer 55 and the sacrificial layer 31. As in the previous embodiment, an additional optional spacing layer 56 can be provided between the spacing film 53 and the first capping film 52a, which acts as an etch stop in a subsequent etching step.

[0103] [000102] Pellicle core layer 51 is preferably made of silicon, such as polysilicon (pSi) or MoSiNx, and has high transmittance in EUV and also provides strength to the pellicle assembly. Spacing film 53 is preferably made of silicon oxide, such as silicon dioxide (SiO2), or a thermal oxide, such as heat-treated SiO2. Spacing film 53 defines a flat surface for receiving further pellicle layers 51, 52a, 52b, 52c, 52d. Additional optional spacing layer 56 can comprise any material having etch selectivity relative to silicon oxide, such as silicon or silicon nitride.

[0104] [000103] The first capping film 52a is preferably made of silicon oxide, for example, silicon dioxide (SiO2). The first capping film 52a is preferably a film that is thinner than the thickness of the pellicle core layer 51.

[0105] [000104] At least one second capping film 52b may preferably be metallic. In a preferred embodiment, the second, third, and fourth capping films 52b, 52c, and 52d may all be metallic. In this preferred embodiment, the second and fourth capping films 52b and 52d are preferably made of boron or a boron-containing material, and the third capping film 52c is made of zirconium or a zirconium-containing material. This top capping film 52e may provide increased strength and / or emissivity to the resulting pellicle assembly 15.

[0106] [000105] This embodiment, also referred to as deposition on a free-standing pellicle, is advantageous over the prior art because an emissive layer is pre-deposited on the pellicle membrane and subsequently removed from the surrounding portion of the material. Significant manufacturing issues arise from deposition on a free-standing pellicle. The present invention allows for deposition of the emissive layer prior to removal, thus avoiding these issues.

[0107] 8A, following removal of pellicle assembly 15 from the surrounding portion of material, the pellicle layer comprises multiple layers, including pellicle core layer 51 disposed between first capping film 52a and release film 52e. First capping film 52a is then desirably removed, leaving only pellicle core layer 51 and release film 52e. This increases the emissivity of pellicle assembly 15 while maintaining mechanical strength.

[0108] 8B. The pellicle assembly 15 of this embodiment is most clearly shown in FIG. 8B. The pellicle assembly 15 comprises a pellicle layer 19 supported on a pellicle boundary 17, a pellicle boundary 17 including a portion of a capping film 52a, an optional spacing layer 56, a spacing layer 53, a sacrificial layer 31, and a planar substrate 30. The optional spacing layer 56 can be further defined as comprising the sacrificial layer 31 disposed between the planar substrate 30 and the spacing layer 53, with the spacing layer 53 disposed between the sacrificial layer and the optional spacing layer 56, the spacing layer being continuous with the capping film 52a. The optional spacing layer 56 preferably comprises an ordered layer made of a silicon layer, a silicon dioxide layer, a thermal oxide layer, an optional silicon layer, and a silicon dioxide layer before adjoining the pellicle core layer 51.

[0109] [000108] Pellicle layer 19 can be further defined as comprising a pellicle core layer 51, preferably made of a silicon-based material such as pSi or MoSiNx, adjacent pellicle boundary 17, and an emissive film 52e, preferably metallic, disposed between pellicle boundary 17 and emissive film 52e. Optionally, at least one additional emissive layer 58 can be added to the pellicle layer, as shown, for example, in FIG. 9 . The at least one additional emissive layer 58 can preferably be metallic. For example, the emissive layer can include boron or a boron-containing material, or zirconium or a zirconium-containing material. This additional emissive layer 58 can provide increased strength and / or emissivity to the resulting pellicle assembly 15. The at least one additional emissive layer 58 is provided, followed by removal of sections of planar substrate 30 and sacrificial layer 31, but before pellicle assembly 15 is completely removed from the surrounding planar substrate 30 and sacrificial layer 31 or optional protective layer.

[0110] Optionally, at least one additional emissive layer 58 can be provided on the underside (i.e., rear or backside) of pellicle layer 19, defined as the plane of pellicle layer 19 adjacent pellicle boundary 17. That is, additional emissive layer 58 can be provided in an area of ​​pellicle layer 19 contained within the cavity defined by pellicle boundary 17. Additional emissive layers can also be provided in regions external to pellicle boundary 17. As shown in the embodiment of FIG. 9, final pellicle assembly 15 can include a pellicle core layer 51 between two emissive layers 52e, 58. Final pellicle assembly 15 can additionally include an emissive layer 58 at least partially surrounding pellicle boundary 17.

[0111] [000110] Although specific reference is made herein to the use of lithographic apparatus in the manufacture of ICs, it should be understood that the lithographic apparatus described herein have other applications, such as the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads, etc. The substrates described herein may be processed, before or after exposure, in, for example, 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 appropriate, the disclosure herein may be applied to these and other substrate processing tools. Furthermore, a substrate may be processed multiple times, for example to create a multi-layer IC, and thus the term substrate, as used herein, may also refer to a substrate that already includes multiple processed layers.

[0112] [000111] The drawings are intended to be illustrative and therefore are not drawn to scale. This is particularly important when considering, for example, the thickness of the pellicle layer, for example, with respect to a planar substrate.

[0113] [000112] While specific embodiments of the present invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. For example, various layers may be interchanged with other layers which perform the same functions.

[0114] [000113] The above description is illustrative and not limiting. Thus, it will be apparent to one skilled in the art that modifications may be made to the invention as described without departing from the scope of the claims set out below.

Claims

1. 1. A pellicle membrane comprising a pellicle boundary region for retaining at least a pellicle layer forming at least a portion of the pellicle membrane, the pellicle boundary region is formed from a substrate having a front surface and a back surface, and one or more layers on the back surface of the substrate; The pellicle membrane comprises a MoSiNx core layer or a MoSiNx core layer having at least one surface covered with a native oxide layer.

2. 2. The pellicle membrane of claim 1, wherein the pellicle layer is formed only by the MoSiNx core layer without any additional functional cap layer.

3. 2. The pellicle membrane of claim 1, wherein the MoSiNx core layer or the MoSiNx core layer having the at least one surface covered with the native oxide layer is covered with a capping layer.

4. 4. The pellicle membrane of claim 3, wherein the capping layer can have a thickness of 0.5 to 10 nm, preferably 1 to 5 nm.

5. 10. The pellicle membrane of claim 1, wherein the MoSiNx core layer has a native oxide layer on both of its surfaces.

6. 6. The pellicle membrane of claim 1, wherein the MoSiNx core layer has a nitrogen variability within its material composition that is equivalent to the MotSipNz. composition.

7. The pellicle membrane of claim 1 , wherein the pellicle layer forming at least a portion of the pellicle membrane is a sacrificial layer.

8. 8. The pellicle membrane of claim 7, wherein the sacrificial layer comprises silicon nitride, silicon oxide, tetraethyl orthosilicate (TEOS), chemical silicon oxide, or thermal silicon oxide.

9. 10. The pellicle membrane of claim 1, wherein the pellicle layer forming at least a portion of the pellicle membrane is a spacing layer that acts as an etch stop layer.

10. 10. The pellicle membrane of claim 9, wherein the spacing layer comprises a silicon layer, a silicon dioxide layer, or a thermal oxide layer.

11. 10. The pellicle membrane of claim 1, wherein the pellicle layer forming at least a portion of the pellicle membrane is the MoSiNx core layer.

12. 10. The pellicle membrane of claim 1, wherein the pellicle layer forming at least a portion of the pellicle membrane is an emissive layer, such as a metal layer.

13. 13. The pellicle membrane of claim 12, wherein the emissive layer comprises a layer of at least B, Zr, Ru, or Mo.

14. 10. The pellicle membrane of claim 1, wherein the pellicle membrane comprises a native silicon oxide layer, a MoSiNx core layer, and a MoSi2 capping film.

15. 10. The pellicle membrane of claim 1, wherein the pellicle membrane comprises two SiON capping layers on each surface of the MoSiNx core layer.

16. 10. The pellicle membrane of claim 1, wherein the pellicle layer further comprises one of pSi, SiC, MoSi2, or a carbon-based material such as a graphene film or a film formed from carbon nanotubes.

Images