EP3714330A1

EP3714330A1 - Porous graphitic pellicle

Info

Publication number: EP3714330A1
Application number: EP18796955.5A
Authority: EP
Inventors: Maxim Aleksandrovich Nasalevich; Evgenia KURGANOVA; Arnoud Willem Notenboom; Mária Péter; Pieter-Jan VAN ZWOL; David Ferdinand Vles
Original assignee: ASML Netherlands BV
Current assignee: ASML Netherlands BV
Priority date: 2017-11-21
Filing date: 2018-11-07
Publication date: 2020-09-30
Also published as: NL2023649B1; JP2021504731A; CN111373328B; NL2023649A; NL2021947B1; TWI840338B; CN111373328A; WO2019101517A1; JP7252950B2; TW201932988A; NL2021947A; NL2021947B9; KR20200087774A

Abstract

A method of manufacturing a pellicle for a lithographic apparatus, said method comprising growing the pellicle in a three-dimensional template and pellicles manufactured according to this method. Also disclosed is the use of a pellicle manufactured according to the method in an EUV lithography apparatus as well as the use of a three-dimensional template in the manufacture of a pellicle.

Description

Porous Graphitic Pellicle

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001 ] This application claims priority of EP application 17202767.4 which was filed on November 21, 2017 and which is incorporated herein in its entirety by reference.

FIELD

[0002] The present invention relates to a method of manufacturing a pellicle for a lithographic apparatus, the use of a pellicle made according to the method of manufacturing, the use of a three- dimensional template to manufacture a pellicle for a lithographic apparatus, and a pellicle for use in a lithographic apparatus.

BACKGROUND

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

[0004] The wavelength of radiation used by a lithographic apparatus to project a pattern onto a substrate determines the minimum size of features which can be formed on that substrate. A lithographic apparatus which uses EUV radiation, being electromagnetic radiation having a wavelength within the range 4-20 nm, may be used to form smaller features on a substrate than a conventional lithographic apparatus (which may for example use electromagnetic radiation with a wavelength of 193 nm).

[0005] A lithographic apparatus includes a patterning device (e.g. a mask or reticle). Radiation is provided through or reflected off the patterning device to form an image on a substrate. A pellicle may be provided to protect the patterning device from airborne particles and other forms of contamination. Contamination on the surface of the patterning device can cause manufacturing defects on the substrate.

[0006] Pellicles may also be provided for protecting optical components other than patterning devices. Pellicles may also be used to provide a passage for lithographic radiation between regions of the lithography apparatus which are sealed from one another. Pellicles may also be used as filters, such as spectral purity filters. Due to the sometimes harsh environment inside a lithography apparatus, particularly an EUV lithography apparatus, pellicles are required to demonstrate excellent chemical and thermal stability.

[0007] Known pellicles may comprise, for example, a freestanding membrane such as a silicon membrane, silicon nitride, graphene or graphene derivatives, carbon nanotube, or other membrane materials. A mask assembly may include the pellicle which protects a patterning device (e.g. a mask) from particle contamination. The pellicle may be supported by a pellicle frame, forming a pellicle assembly. The pellicle may be attached to the frame, for example, by gluing a pellicle border region to the frame. The frame may be permanently or releasably attached to a patterning device.

[0008] During use, the temperature of a pellicle in a lithographic apparatus increases to anywhere from around 500 up to 1000°C or higher. These high temperatures can damage the pellicle and it is therefore desirable to improve ways by which to dissipate the heat in order to lower the operating temperature of the pellicle and improve pellicle lifespan.

[0009] It has been found that the lifetime of carbonaceous pellicles, such as pellicles comprising freestanding graphene membranes or other carbon-based membranes, may be limited and that carbon- based pellicles may suffer from particular disadvantages when used in a lithographic apparatus.

[00010] Graphene pellicles comprise one or more parallel, thin layers of graphene. Such pellicles are for example around 6 to around 10 nm thick and may demonstrate high density. Due to the structure of such graphene pellicles the uniformity of the EUV radiation passing through the pellicle is not substantially altered. However, depending on the way in which they are manufactured, some graphene pellicles may have relatively low mechanical strength. Although graphene is one of, if not the, strongest materials known, roughness on the surface of the graphene layers caused by the substrates on which the graphene pellicles are produced negatively impacts the strength of the pellicle. During use of a pellicle, the lithographic apparatus in which the pellicle is used may be flushed with a gas. Also, during exposure the pellicle will undergo a substantial heat load from the EUV radiation. Stress variations of the pellicle induced by such factors can result in damage to the pellicle if it is not sufficiently strong. The pellicle may break and contaminate various parts of the lithographic apparatus, which is undesirable.

[00011] Another type of carbonaceous pellicle is based on carbon nanotubes. Such pellicles do not have the same dense, parallel layer structure as multi-layer graphene pellicles, but are rather formed of a network of carbon nanotubes in a mesh. The boundaries of carbon nanotube-based pellicles are less defined than the boundaries of multi-layer graphene pellicles and the carbon nanotubes can alter the uniformity of the radiation beam passing through the pellicle, for example due to scattering. This is undesirable as the variance in the uniformity of the radiation beam can be reflected in the final product. Given the extremely high precision required by a lithography machine, even small differences in the uniformity of the radiation beam can result in decreased exposure performance. However, a benefit of pellicles based on carbon nanotubes is that they are strong and so they can meet the strength requirements for use in a lithographic apparatus.

[00012] It is therefore desirable to provide a method for manufacturing a carbonaceous pellicle that is sufficiently strong to be able to be used in a lithographic apparatus, such as an EUV lithography apparatus, and which also has high EUV transmissivity, for example of more than 90%, and which does not adversely affect the uniformity of the radiation beam passing through the pellicle. [00013] Whilst the present application generally refers to pellicles in the context of lithography apparatus, in particular EUV lithography apparatus, the invention is not limited to only pellicles and lithography apparatus and it is appreciated that the subject matter of the present invention may be used in any other suitable apparatus or circumstances.

[00014] For example, the methods of the present invention may equally be applied to spectral purity filters. EUV sources, such as those which generate EUV radiation using a plasma, in practice do not only emit desired‘in-band’ EUV radiation, but also undesirable (out-of-band) radiation. This out-of- band radiation is most notably in the deep UV (DUV) radiation range (from 100 to 400 nm). Moreover, in the case of some EUV sources, for example laser produced plasma EUV sources, the radiation emitted from the laser, for example at 10.6 microns, may be a source of out-of-band radiation (e.g. IR radiation).

[00015] In a lithographic apparatus, spectral purity may be desired for several reasons. One reason is that resist is sensitive to out of -band wavelengths of radiation, and thus the image quality of exposure patterns applied to the resist may be deteriorated if the resist is exposed to such out-of-band radiation. Furthermore, out-of-band radiation, for example infrared radiation in some laser produced plasma sources, leads to unwanted and unnecessary heating of the patterning device, substrate, and optics within the lithographic apparatus. Such heating may lead to damage of these elements, degradation in their lifetime, and/or defects or distortions in patterns projected onto and applied to a resist-coated substrate.

[00016] A spectral purity filter may be used as a pellicle, and vice versa. Therefore, reference in the present application to a‘pellicle’ is also reference to a‘spectral purity filter. Although reference is primarily made to pellicles in the present application, all of the features could equally be applied to spectral purity filters.

[00017] In a lithographic apparatus (and/or method) it is desirable to minimise the losses in intensity of radiation which is being used to apply a pattern to a resist coated substrate. One reason for this is that, ideally, as much radiation as possible should be available for applying a pattern to a substrate, for instance to reduce the exposure time and increase throughput. At the same time, it is desirable to minimise the amount of undesirable radiation (e.g. out-of-band) radiation that is passing through the lithographic apparatus and which is incident upon the substrate. Furthermore, it is desirable to ensure that a pellicle used in a lithographic method or apparatus has an adequate lifetime, and does not degrade rapidly over time as a consequence of the high heat load to which the pellicle may be exposed, and/or the hydrogen (or the like, such as free radical species including H* and HO*) to which the pellicle may be exposed. It is therefore desirable to provide an improved (or alternative) pellicle, and for example a pellicle suitable for use in a lithographic apparatus and/or method.

SUMMARY [00018] The present invention has been made in consideration of the aforementioned problems with known methods of manufacturing pellicles and with known pellicles.

[00019] According to a first aspect of the present invention, there is provided a method of manufacturing a pellicle for a lithographic apparatus, said method comprising: growing the pellicle in a three-dimensional template material.

[00020] Known carbon-based pellicles are currently based effectively on solid, layered 2 dimensional materials. For example, graphene pellicles comprise multiple layers of graphene. Similarly, silicon pellicles are manufactured on solid silicon wafers, which may or may not be coated with other protective cap layer materials, such as metals. As such, these pellicle materials are grown as layers on surfaces, which are two-dimensional, and are solid, or have very little voids within them (i.e. a low porosity). On the other hand, pellicles based on carbon nanotubes comprise a disordered mesh of carbon nanotubes which have significant void space within them, but are disordered, which negatively impacts on the uniformity of the radiation beam passing through due to scattering. It is desirable to provide a pellicle with a regular and well-defined three-dimensional structure.

[00021] It has been found that manufacturing a pellicle within a three-dimensional template provides a pellicle with a regular and well-defined three dimensional structure. The structure of the pellicles manufactured according to the method of the present invention is also porous, as with carbon nanotube pellicles, but has a more regular and well-defined three dimensional structure which provides sufficient strength to be used in a lithography apparatus, and enough flexibility to accommodate changes in temperatures and stress on the pellicle. It has been surprisingly found that the resulting pellicle has acceptable EUV transmissivity of greater than 90%and does not adversely affect the uniformity of the radiation beam passing through.

[00022] The three-dimensional template may be a zeolite. Zeolites are microporous, aluminosilicate materials which are commonly used as adsorbents and catalysts. These have regular internal pore structures into which small molecules are able to pass.

[00023] The zeolite may be any suitable zeolite. For example, the zeolite may be Zeolite A, Zeolite Beta, mordenite, Zeolite Y, or chabazite. These are the most commonly used and most readily available zeolites, although it will be appreciated that other zeolites are also considered to be suitable for the present invention.

[00024] The zeolite may be a modified zeolite. The modified zeolite may comprise zeolite which has been doped with a suitable material. Suitable materials include one or more of lanthanum, zinc, molybdenum, yttrium, calcium, tungsten, vanadium, titanium, niobium, chromium, tantalum, and hafnium. It has been surprisingly found that by doping the zeolite with one or more of these elements decreases the temperature at which carbonization is able to occur within the pores of the zeolite. The doping can be carried out by any suitable means, such as ion exchange. For example, sodium ions in the zeolite may be exchanged with lanthanum ions. [00025] The method may comprise providing a carbon source, preferably a gaseous carbon source. The carbon source may be passed into the three-dimensional template material. Since the three- dimensional template comprises an internal network of pores, the carbon source material is able to impregnate the three dimensional template.

[00026] The carbon source may be a saturated or unsaturated Cl to C4 hydrocarbon. It is possible to use hydrocarbons having more than four carbon atoms, but the absorption process is slower since these are liquid at ambient temperatures. Of course, if the absorption into the three dimensional template took place at temperatures above ambient, longer chain hydrocarbons may be used. The hydrocarbons are preferably linear.

[00027] Examples of suitable carbon sources include methane, ethane, ethane, ethyne, propane, propene, propadiene, propyne, butane, butene, butadiene, butatriene, and butyne. Since the carbon source is intended to be primarily for the provision of carbon, it is preferable to use unsaturated hydrocarbons as these have advantageous carbon to hydrogen ratios and are more reactive that saturated hydrocarbons. For example, a preferred carbon source is ethyne as it is most reactive and is also small, so is able to diffuse into the three dimensional template easily.

[00028] The method may comprise heating the three dimensional template material up to a first temperature to carbonise the carbon source. Once the carbon source has been passed into the internal pores of the three dimensional template, heating the material causes it to carbonise. The carbonization process is enhanced by the aforementioned doping of the three dimensional material with metal ions. The metal ions are selected as they form strong carbide bonds. Without the doping, the temperature required to carbonise the carbon source is much greater and results in carbon only forming on the surface of the three dimensional template and does not form a carbonaceous network which substantially corresponds to the internal pore structure of the three dimensional material in which the carbon source is contained.

[00029] The first temperature may be from around 350C to around 800C, and preferably around 650C. Without doping, temperatures in excess of 800C are required for carbonization.

[00030] The three dimensional material may subsequently be heated to a second temperature which is higher than the first temperature. The second temperature may be around 850C or more. Heating to the second, higher temperature causes the carbon to become more highly ordered and therefore stronger.

[00031] Once the heating has been completed, the carbonaceous pellicle is retrieved by dissolving the three dimensional template. Where the three-dimensional template is a zeolite, the zeolite may be dissolved by exposure to a strong acid, such as hydrochloric acid or hydrofluoric acid, and may subsequently be exposed to a hot basic solution, such as sodium hydroxide. The exact method for dissolving the zeolite is not restricted to the examples given, and any suitable method which dissolves the zeolite whilst leaving the carbonaceous pellicle may be used. [00032] The three dimensional material may be prepared from a silicon wafer by known means. Preferably, the silicon wafer is single crystal silicon. The preparation from a silicon wafer allows the exact thickness and nature of the zeolite to be controlled. Thus, different zeolites can be prepared depending on the exact nature of the pellicle required, with some having larger pores and others having smaller pores.

[00033] A portion of the surface of the silicon wafer may be converted to a zeolite material, or a zeolite material may be prepared on the surface of a silicon wafer. Both techniques are known in the art. The thickness of the zeolite may be from around 50 to around 150 nm, from around 80 nm to around 120 nm, and preferably around 100 nm. If the zeolite is too thin, the resulting pellicle may not be thick enough to have the necessary strength to be used in an EUV lithography apparatus. On the other hand, if the zeolite is too thick, the resulting pellicle may be too thick and have undesirably low EUV transmissivity, such as, for example, less than 90%. The exact thickness of the pellicle can be achieved by removing material from a pellicle until the desired thickness is met.

[00034] According to a second aspect of the present invention, there is provided the use of a three- dimensional template in the manufacture of a pellicle.

[00035] As described above, currently know pellicles are manufactured by forming two dimensional layers on surfaces. There is no known pellicle which is produced inside a three- dimensional template. The use of a three dimensional template allows a pellicle with a very regular and predictable structure to be formed. The resulting pellicle is stronger than existing graphene pellicles, and does not cause unwanted diffraction or scattering of the radiation beam as is the case with carbon nanotube-based pellicles.

[00036] The three-dimensional template may be any zeolite described in relation to the first aspect of the present invention.

[00037] According to a third aspect of the present invention, there is provided a three-dimensional template for the manufacture of a pellicle.

[00038] Preferably, the pellicle is a carbonaceous pellicle.

[00039] Preferably, the three-dimensional template is a zeolite as described with reference to the first aspect of the present invention.

[00040] According to a fourth aspect of the present invention, there is provided a pellicle having a three-dimensional structure which substantially corresponds to the internal pore structure of a zeolite. The pellicle is preferably carbonaceous.

[00041] Since there is no known pellicle which is manufactured using a three-dimensional template, there is no known pellicle which has a three-dimensional structure which substantially corresponds to the internal pore structure of a zeolite. As described above, this provides a pellicle which is strong and does not interfere with the uniformity of a radiation beam passing through the pellicle. [00042] According to a fifth aspect of the present invention, there is provided a pellicle for a lithographic apparatus obtained or obtainable by the method according to the first aspect of the present invention.

[00043] Due to limitations of known method of manufacturing pellicles and the absence of any pellicles made using a three-dimensional template, until now, there has been no way of making a pellicle having a regular three-dimensional ordering which is strong enough for use in a lithographic apparatus.

[00044] According to a sixth aspect of the present invention, there is provided the use of a pellicle manufactured according to a method of the first aspect of the present invention, or according to the fourth or fifth aspects of the present invention in a lithographic apparatus.

[00045] In summary, the methods of the present invention allow for the manufacture of a pellicle, in particular a carbonaceous pellicle, which is suitable for use in an EUV lithographic apparatus. It has not been previously possible to manufacture such a pellicle. The pellicles manufactured according to the methods of the present invention are able to resist the high temperatures achieved when the pellicle is in use and also withstand mechanical forces on the pellicle during use of the lithographic apparatus which would damage known pellicles. Furthermore, having a pellicle with a regular three-dimensional structure means that the uniformity of the radiation beam is not adversely affected when passing through the pellicle. It is believe that the three dimensional structure which substantially corresponds to the internal pore structure of a zeolite provides the pellicle with sufficient strength to be used in a lithographic apparatus, but also enough flexibility to withstand any temperature and/or pressure changes during use.

[00046] The present invention will now be described with reference to a carbonaceous pellicle which is formed within the pore structure of a zeolite. However, it will be appreciated that the present invention is not limited to pellicles and is equally applicable to spectral purity filters. In addition, due to the high surface area of the resulting material, it could also be used in charge storage devices, such as batteries or capacitors. Thus, although the methods, uses, and products are described in the context of pellicles and lithography, it will be appreciated that such methods, uses, and products could also be used in the manufacture of components for batteries and capacitors.

BRIEF DESCRIPTION OF THE DRAWINGS

[00047] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawing, in which:

Figure 1 depicts a lithographic system comprising a lithographic apparatus and a radiation source according to an embodiment of the invention.

DETAILED DESCRIPTION [00048] Figure 1 shows a lithographic system including a pellicle 15 according to the fourth and fifth aspects of the present invention or manufactured according to the methods of the first aspect of the present invention according to one embodiment of the invention. The lithographic system comprises a radiation source SO and a lithographic apparatus LA. The radiation source SO is configured to generate an extreme ultraviolet (EUV) radiation beam B. 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. The illumination system IL is configured to condition the radiation beam B before it is incident upon the patterning device MA. The projection system is configured to project the radiation beam B (now patterned by the mask MA) onto the substrate W. The substrate W may include previously formed patterns. Where this is the case, the lithographic apparatus aligns the patterned radiation beam B with a pattern previously formed on the substrate W. In this embodiment, the pellicle 15 is depicted in the path of the radiation and protecting the patterning device MA. It will be appreciated that the pellicle 15 may be located in any required position and may be used to protect any of the mirrors in the lithographic apparatus.

[00049] The radiation source SO, illumination system IL, and projection system PS may all be constructed and arranged such that they can be isolated from the external environment. A gas at a pressure below atmospheric pressure (e.g. hydrogen) may be provided in the radiation source SO. A vacuum may be provided in 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.

[00050] The radiation source SO shown in Figure 1 is of a type which may

be referred to as a laser produced plasma (LPP) source). A laser 1, which may for example be a CO₂ laser, is arranged to deposit energy via a laser beam 2 into a fuel, such as tin (Sn) which is provided from a fuel emitter 3. Although tin is referred to in the following description, any suitable fuel may be used. The fuel may for example be in liquid form, and may for example be a metal or alloy. The fuel emitter 3 may comprise a nozzle configured to direct tin, e.g. in the form of droplets, along a trajectory towards a plasma formation region 4. The laser beam 2 is incident upon the tin at the plasma formation region 4. The deposition of laser energy into the tin creates a plasma 7 at the plasma formation region 4. Radiation, including EUV radiation, is emitted from the plasma 7 during de-excitation and recombination of ions of the plasma.

[00051] The EUV radiation is collected and focused by a near normal incidence radiation collector 5 (sometimes referred to more generally as a normal incidence radiation collector). The collector 5 may have a multilayer structure which is arranged to reflect EUV radiation (e.g. EUV radiation having a desired wavelength such as 13.5 nm). The collector 5 may have an elliptical configuration, having two ellipse focal points. A first focal point may be at the plasma formation region 4, and a second focal point may be at an intermediate focus 6, as discussed below.

[00052] The laser 1 may be separated from the radiation source SO. Where this is the case, the laser beam 2 may be passed from the laser 1 to the radiation source SO with the aid of a beam delivery system (not shown) comprising, for example, suitable directing mirrors and/or a beam expander, and/or other optics. The laser 1 and the radiation source SO may together be considered to be a radiation system.

[00053] Radiation that is reflected by the collector 5 forms a radiation beam

B. The radiation beam B is focused at point 6 to form an image of the plasma formation region 4, which acts as a virtual radiation source for the illumination system IL. The point 6 at which the radiation beam B is focused may be referred to as the intermediate focus. The radiation source SO is arranged such that the intermediate focus 6 is located at or near to an opening 8 in an enclosing structure 9 of the radiation source.

[00054] The radiation beam B passes from the radiation source SO into the illumination system IL, which is 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. The faceted field mirror device 10 and faceted pupil mirror device 11 together 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 upon the patterning device MA held by the support structure MT. The patterning device MA reflects and patterns the radiation beam B. The illumination system IL may include other mirrors or devices in addition to or instead of the faceted field mirror device 10 and faceted pupil mirror device 11.

[00055] Following reflection from the patterning device MA the patterned radiation beam B enters the projection system PS. The projection system comprises a plurality of mirrors 13, 14 which are configured to project the radiation beam B onto a substrate W held by the substrate table WT. The projection system PS may apply a reduction factor to the radiation beam, forming an image with features that are smaller than corresponding features on the patterning device MA. A reduction factor of 4 may for example be applied. Although the projection system PS has two mirrors 13, 14 in Figure 1, the projection system may include any number of mirrors (e.g. six mirrors).

[00056] The radiation sources SO shown in Figure 1 may include components which are not illustrated. For example, a spectral filter may be provided in the radiation source. The spectral filter may be substantially transmissive for EUV radiation but substantially blocking for other wavelengths of radiation such as infrared radiation.

[00057] In an exemplary method according to the present invention, a three dimensional template in the form of a zeolite is provided. This may have been formed based on a silicon wafer or by any other suitable means. The exemplary zeolite is Zeolite-Y in which at least a portion of the sodium ions has been exchanged with lanthanum ions via ion exchange. A carbon source comprising ethyne gas is passed over the zeolite and the ethyne gas is allowed to diffuse into the internal pores of the zeolite. The zeolite is heated to around 650C in order to carbonise the ethyne gas and form a carbon structure inside of the zeolite which substantially corresponds to the internal structure of the zeolite. Following this, the zeolite is heated to around 850C in order to provide a more highly ordered carbonaceous pellicle. The zeolite is then dissolved by dissolution in hydrofluoric acid in order to recover the pellicle.

[00058] In this way, it is possible to control the structure of the resulting pellicle and use different zeolites with different sizes to modify the exact structure of the pellicle. The resulting pellicle has EUV transmissivity of greater than 90% and is strong enough for use in a lithographic apparatus.

[00059] The term“EUV radiation” may be considered to encompass electromagnetic radiation having a wavelength within the range of 4-20 nm, for example within the range of 13-14 nm. EUV radiation may have a wavelength of less than 10 nm, for example within the range of 4-10 nm such as 6.7 nm or 6.8 nm.

[00060] While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. The descriptions above are intended to be illustrative, 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

CLAIMS:

1. A method of manufacturing a pellicle for a lithographic apparatus, said method comprising: growing the pellicle in a three-dimensional template.

2. A method according to Claim 1, wherein the template is a zeolite.

3. A method according to Claim 2, wherein the zeolite is selected from Zeolite A, Zeolite beta, mordenite, Zeolite Y, ZSM-5, and chabazite.

4. A method according to Claim 2 or Claim 3, wherein the zeolite is a modified zeolite.

5. A method according to Claim 4, wherein the modified zeolite comprises zeolite doped with one or more of lanthanum, zinc, molybdenum, yttrium, calcium, tungsten, vanadium, titanium, niobium, chromium, tantalum, and hafnium.

6. A method according to any preceding claim, said method comprising providing a carbon source and passing the carbon source into the three-dimensional template material.

7. A method according to Claim 6, wherein the gaseous carbon source comprises at least one saturated or unsaturated Cl to C4 hydrocarbon.

8. A method according to Claim 7, wherein the gaseous carbon source comprises at least one of methane, ethane, ethene, ethyne, propane, propene, propadiene, propyne, butane, butene, butadiene, butatriene, and butyne, preferably, ethyne.

9. A method according to any of Claims 6 to 8, wherein the method comprises heating the three- dimensional template up to a first temperature to carbonise the carbon source.

10. A method according to Claim 9, wherein the first temperature is from around 350°C to around 800°C.

11. A method according to Claim 9 or 10, wherein the three-dimensional template is heated to a second temperature which is higher than the first temperature.

12. A method according to Claim 11, wherein the second temperature is around 850°C.

13. A method according to any of Claims 9 to 12, wherein the three-dimensional template is dissolved to liberate the carbonaceous pellicle.

14. A method according to Claim 13, wherein the three-dimensional template is dissolved by exposure to a strong acid, preferably hydrofluoric acid or hydrochloric acid, and optionally then by exposure to a hot basic solution, such as sodium hydroxide.

15. A method according to any preceding claim, wherein the three-dimensional template is produced using a silicon wafer, preferably single crystal silicon.

16. A method according to Claim 15, wherein at least a portion of the silicon wafer is converted into a zeolite, or wherein a zeolite film is deposited on a surface of the silicon wafer.

17. A method according to Claim 16, wherein the thickness of the zeolite is from around 50 to around 150 nm, preferably from around 80 to around 120 nm, and most preferably around 100 nm.

18. A method according to any of Claims 5 to 17, wherein the zeolite is doped via ion-exchange.

19. Use of a three-dimensional template in the manufacture a pellicle, preferably a carbonaceous pellicle.

20. Use according to Claim 19, wherein the three-dimensional template is a zeolite.

21. Use according to Claim 20, wherein the zeolite is a modified zeolite, which has been doped with one or more of lanthanum, zinc, molybdenum, yttrium, calcium, tungsten, vanadium, titanium, niobium, chromium, tantalum, and hafnium.

22. A three-dimensional template for the manufacture of a pellicle, wherein the template comprises a zeolite, preferably wherein the pellicle is a carbonaceous pellicle.

23. A three-dimensional template according to Claim 22, wherein the zeolite is doped with one or more of lanthanum, zinc, molybdenum, yttrium, calcium, tungsten, vanadium, titanium, niobium, chromium, tantalum, and hafnium.

24. A pellicle having a three-dimensional structure which substantially corresponds to the internal pore structure of a zeolite.

25. A pellicle according to Claim 24, wherein the pellicle is carbonaceous.

26. A pellicle for a lithographic apparatus obtainable or obtained by the method according to any of Claims 1 to 18.

27. Use of a pellicle manufactured by the method according to any of Claims 1 to 18 or according to any of Claims 24 to 26 in a lithographic apparatus.