Method of producing a patterned material on a film

Abstract

The present invention provides a method for producing a patterned material on a film disposed on a support. The method comprising the steps of: providing a layered structure comprising a sacrificial photoresist layer disposed on the film, and an overlying photoresist layer disposed on the sacrificial photoresist layer. The sacrificial photoresist layer is adapted to be soluble in resist developer (either before or after exposing to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left. The overlying photoresist layer and the sacrificial photoresist layer are patterned to produce masked and un-masked areas of the film layer. A material is deposited on at least the un-masked areas of the film. In the masked areas, the sacrificial photoresist layer is exposed to solvent such that the sacrificial photoresist layer releases from the underlying film, thereby providing the film with the patterned material thereon. Also disclosed is the use of a layered structure comprising a support, a film disposed on the support, a sacrificial photoresist layer disposed on the film, and an overlying photoresist layer disposed on the sacrificial photoresist layer. Also disclosed is a method of making the layered structure. The present invention enables the suppression or elimination of fabrication-induced photoresist (PR) residues on material layers and / or at the interfaces of material layers, which finds particular utility in the fabrication of two-dimensional (2D) electronic devices such as field-effect transistors (2D-FETs).

Description

METHOD OF PRODUCING A PATTERNED MATERIAL ON A FILMRELATED APPLICATION

[0001] The present application claims priority to Australian Provisional Patent Application No. 2024901900, filed 21 June 2024, the content of which is incorporated herein by reference in its entirety.FIELD OF THE INVENTION

[0002] The present invention relates to the field of micro / nano-manufacturing, and in particular to microelectronic manufacturing processes. In particular, the present invention enables the suppression or elimination of fabrication-induced photoresist residues on material layers and / or at the interfaces of material layers, which finds particular utility in the fabrication of two-dimensional (2D) electronic devices such as 2D field-effect transistors (2D-FETs). However, it will be appreciated that the invention is not limited to this particular field of use.BACKGROUND OF THE INVENTION

[0003] The following discussion of the prior art is provided to place the invention in an appropriate technical context and enable the advantages of it to be more fully understood. It should be appreciated, however, that any discussion of the prior art throughout the specification should not be considered as an express or implied admission that such prior art is widely known or forms part of the common general knowledge in the field.

[0004] Two-dimensional layered materials, such as graphene or two-dimensional transition metal dichalcogenides (TMDs), have recently captured enormous attention in the field of micro / nano-electronics, optoelectronics and spintronics since the discovery that graphene or monolayer semiconducting TMDs have preferred physical and electrical properties such that the two-dimensional (2D) layered materials have good developmental and applied potential. However, contaminates, especially photoresist residues, are easily adsorbed onto the surface of the 2D layered materials. Accordingly, after the photoresist on the 2D layered materials is patterned and subsequently developed, the photoresist residues may still remain on the exposed 2D layered materials. During the following step of depositing a metal layer, for example, on the exposed 2D layered semiconductor to form a contact for connecting to an external circuit, the photoresist residues will exist between the 2D layered semiconductor and the metal electrode layer.

[0005] However, the photoresist residues or the other contaminates existing at the interface of the metal electrode layer and the 2D layered semiconductor will seriously affect the quality of the electrical contact between the metal layer and the 2D layered semiconductor. That is, it is harder for the electrons to tunnel from the 2D layered semiconductor to the metal layer due to the photoresist residues or contaminates. Furthermore, poor electrical contact may also result in higher power consumption of the electronic device.

[0006] Similarly, residues at the channel / dielectric interfaces and dielectric / gate electrode interfaces can seriously affect the capability of gate modulation, resulting in quenched device performance, such as reduced ON / OFF ratio and deteriorated subthreshold swing.

[0007] Since the 2D layered material has an ultrathin thickness of a monoatomic layer or a few atomic layers, the 2D layered material is more sensitive to surface contaminates, and a higher surface cleanliness of the 2D layered material is required compared to three- dimensional materials. Additionally, the surface cleanliness of the 2D layered material has become a critical factor affecting the overall electrical performance of the 2D electronic device.

[0008] Previously, these photoresist-induced residues (“PR residues”) have been subject to a sequence of cleaning procedures, such as ultrasonic treatment, treatment with acid, or plasma. However, removing such PR residues from 2D materials is extremely difficult. Due to their atomically thin structure, high susceptibility to oxidation, and relatively weak adhesion to substrates, 2D materials are extremely sensitive to aggressive cleaning processes. One current solution to tackle these challenges employs the use of soft plasma or ultraviolet (UV) / ozone to clean such residues. However, it has been observed that these methods induce damage to the atomically thick materials. Another method that has been investigated is contact mode atomic force microscopy (AFM). However, this is inapplicable for mass production. A further option is to utilize thermal annealing in forming gas or high vacuum, however, this method cannot effectively remove the residues while protecting the 2D materials from degradation. Some workers have suggested the use of polydimethylglutarimide-based resists for reducing such residues, but the use of these resists requires additional N-methyl- pyrrolidinone cleaning, which is too aggressive for 2D semiconductors and can result in “peeling off’.

[0009] It is an object of the present invention to overcome or ameliorate one or more the disadvantages of the prior art, or at least to provide a useful alternative.

[0010] It is an object of at least one preferred embodiment of the present invention to provide an efficient method to suppress or even eliminate fabrication-induced PR residues in the production of 2D electronics. In particular, it is an object of at least one preferredembodiment of the present invention to provide a method which avoids fabrication-induced PR residues on the contact and channel areas to produce an “ultraclean” surface / interface of 2D electronic devices.

[0011] It is an object of at least one preferred embodiment of the present invention to provide efficient and scalable methods which eliminate unwanted PR residues on the 2D layered material used to make 2D-FETs. It is an object of another preferred embodiment of the present invention to provide methods that reduce or eliminate PR residues, thereby reducing device-to-device variation to thereby enhance the performance of 2D FETs and equivalent or similar devices. It is an object of yet a further preferred embodiment of the present invention to provide methods that reduce or eliminate PR residues that are suitable for mass production, and are compatible with current main-steam mass production facilitates, and whereby no additional facilities and / or or new materials are required compared to existing facilities / materials.

[0012] It is an object of at least one preferred embodiment of the present invention to form “a clean contact”, ensuring that the interface between the patterned material (e.g., electrode) and film (e.g., channel) remains free, or substantially free of contaminants.SUMMARY OF THE INVENTION

[0013] The semiconductor industry has experienced unprecedented developments over recent times, while gaining importance in all aspects of life. However, the conventional silicon industry is nearly approaching a ceiling because of its limited potential for power and dimensional miniaturization. 2D semiconductors have notable advantages over conventional bulk semiconductors. Most notably, their greater resistance to short-channel effects makes them particularly promising for the development of high performing transistors, which are crucial components of all electronic devices. Simultaneously, 2D semiconductors and other 2D materials are thermodynamically stable as single atomic layers, and have a thickness of about half a nanometer. Ideally, the surfaces of these 2D layers are inert and free of dangling bonds and other defects, which allow for the formation of nearly defect-free interfaces in 2D electronic devices.

[0014] The present inventors have now developed surprisingly efficient and scalable methods which eliminate unwanted PR residues on the 2D layered material used to make 2D- FETs, which would ordinarily be present during main-stream manufacturing / fabrication processes. The present invention enables improved metal-semiconductor contacts and other interfaces, such as semiconductor-insulator and insulator-metal contacts, in 2D-FETs to also significantly enhance their performance. The present invention reduces or eliminates residues,and residue-imposed effects, such as doping, device-to-device variation and quenched gate modulation, all of which combine to enhance the performance of 2D FETs and equivalent or similar devices. Additionally, the invention disclosed herein is suitable for mass production, and is compatible with current main-steam mass production facilities. Furthermore, no additional facilities or new materials are required in the present invention. Accordingly, the novel methods disclosed herein are suitable for the large-scale production of 2D electronic devices.

[0015] Using 2D layered material as an example of a film layer, the present invention provides the P / N-PR (positive / negative photoresist) method to form a patterned mask for subsequent deposition (adding new material) processes to create the desired microstructures on the film layer, which is free, or substantially free of PR residues. With this strategy, residues, and residue-imposed effects, such as doping, increased contact resistances, induced leakage current, and quenched gate modulation, can be remarkably avoided to enhance the performance of electronics containing the film and desired microstructures.

[0016] It is envisaged that the present invention can be utilized for individual components within field-effect transistors (FETs) and equivalent or similar devices requiring a patterned photoresist mask for subsequent deposition (adding new material) processes to create the desired microstructures on the film layer. Essentially, the invention could be deployed for, for example: (a) enhancing the surface / interface condition between the source / drain electrodes and the channel, (b) improving the surface / interface conditions between the gate dielectric and the channel and / or (c) improving the surface / interface conditions between the gate electrode and the gate dielectric.

[0017] In particular, the present invention provides a sacrificial photoresist layer which is “sandwiched” or disposed between the (underlying) film and the (overlying) photoresist layer. In one preferred embodiment, the sacrificial photoresist layer is adapted to be soluble in resist developer (either before or after exposure to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left behind.

[0018] In one embodiment, the sacrificial photoresist layer may be a single layer having this property, or alternatively, the sacrificial photoresist layer may be a plurality of layers that each have properties which, when combined, mean that the sacrificial photoresist layer overall is adapted soluble in resist developer (either before or after exposing to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left. The surprising utility of the sacrificial protection layer will become apparent in light of the current / conventional method of 2D FET fabrication. In this regard, the left-hand sideof Figure 1 shows the conventional method in which in Step 1 a film (2D layered material) is disposed on a support and coated with a photoresist (“PR coating”), either negative photoresist (N-PR), or positive photoresist (P-PR). It will be appreciated that the PR coating is in direct contact with the film. In Step 2, a standard lithography process is undertaken to pattern the PR coating as a mask for subsequent deposition (adding new material) processes. In Step 3, a material deposition step is undertaken. In Step 4, a solvent “lift off” process is undertaken to remove all photoresists on the film as well as the deposited materials overlaying on these photoresists. Due to the nature of P-PR, the sidewalls of patterned P-PR tend to be “overcut”, which tends to impair the successful lift-off of the deposited material (i.e. , “Step 5, P-PR”), whereas the nature of N-PR means the sidewalls of N-PR tend to be “undercut”, and the liftoff of the deposited material tends to be more successful. However, the nature of N-PR results in some unwanted PR residue remaining on the underlying film (i.e., “Step 5, N-PR”), which causes deleterious effects as discussed above.

[0019] As the skilled addressee will know, a well-controlled undercut significantly improves the lift-off process. The different sidewalls of P-PR and N-PR are caused by their different chemical properties, and thus they react differently to light exposure. Inevitably, P-PR tends to form overcut while N-PR is prone to form undercut. For example, the use of P-PR tends to form trapezoid resist islands, and as a result subsequent deposition (adding new material) processes can result in material deposited onto the island sidewalls with outward-inclining shapes, which block the solvents from penetrating these islands inwards and dissolving the P- PR. It is for this primary reason why dissolving P-PR with overcut usually fails to remove the redundant deposited material, resulting in incomplete lift-off that bridges the material over the designed patterns. Alternatively, N-PR tends to form inverted trapezoids with “shadows”, making the cliff-like sidewalls nearly free of deposited metals. Solvents such as acetone can relatively easily dissolve these islands from their edges.

[0020] Turning now to the right-hand side of Figure 1 , the use of a sacrificial photoresist layer as described herein is exemplified. Under the heading “additional steps”, a coating of a sacrificial photoresist layer (P-PR) is provided on the film. In particular, the P-PR layer is exposed to UV (or DUV, EUV) which enables its solubility in the developer and thus allows it to function as the sacrificial photoresist layer. Steps 1 and 2 are then undertaken in a similar way to the conventional method, to produce a patterned layered structure comprising the N- PR coating disposed on the sacrificial photoresist layer, which is disposed on the film. Steps 3, 4, and 5 are then undertaken in a similar way to the conventional method, to thereby provide a patterned material on the film layer with no unwanted PR residue remaining on the film and at the interface between the patterned material and the film layer. This is because the N-PR coating is never in contact with the film, which is only made possible due to the use of thesacrificial photoresist layer that is adapted to be soluble in resist developer (either before or after exposure to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left. Exposure to the solvent causes all patterned photoresist masks and deposited materials above the photoresist masks to lift off (or dissolve or peel away from) the film layer at the same time, facilitated by the ideal inverted trapezoids sidewalls formed by the stack of the sacrificial photoresist layer and N-PR.

[0021] In the embodiment discussed above and in Figure 1 , the sacrificial photoresist layer is UV-softened P-PR and the overlying photoresist layer is a coating of N-PR. However, alternatively, the sacrificial photoresist layer may be other materials soluble in resist developer (either before or after exposure to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left.

[0022] In summary, the inventors describe herein a novel “lift-off” method to avoid the presence of PR residues on the film layer and at the interface between the patterned material and the film layer that would ordinarily be present with the conventional method. The provision of the sacrificial photoresist layer prevents the source of the PR residues from coming into contact with the film layer during lithography processes for subsequent deposition to create the desired microstructures on the film layer, and mitigates the aforementioned technical challenges that relate to the existence of PR residues and ineffective residue cleaning processing.

[0023] The skilled addressee will appreciate that the present invention may provide one or more significant advantages and improvements in the field and / or in view of the prior art. For example, these advantages include:(i) The ability to substantially avoid or avoid PR residues on a film having a patterned material, and avoid PR residues at the interface between the patterned material and the film thereon.(ii) The ability to form the well-defined vertical or inverted-trapezoid sidewall along with the overlaying photoresist after development, and thus facilitate material lift-off process to form a material pattern.

[0024] It is envisaged that the present invention can be utilized for individual components within FETs and equivalent or similar devices requiring a patterned photoresist mask for subsequent deposition (adding new material) processes. Essentially, the invention can be used for:Enhancing the surface / interface condition between the source / drain electrodes and the channel.• Improving the surface / interface conditions between the gate dielectric and the channel.• Improving the surface / interface conditions between the gate electrode and the gate dielectric.

[0025] According to a first aspect, the present invention provides a method for producing a patterned material on a film disposed on a support, the method comprising the steps of: providing a layered structure comprising a sacrificial photoresist layer disposed on the film, and an overlying photoresist layer disposed on the sacrificial photoresist layer, the sacrificial photoresist layer adapted to be soluble in resist developer (either before or after exposing to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left; patterning the overlying photoresist layer and the sacrificial photoresist layer to produce masked and un-masked areas of the film layer; depositing a material on at least the un-masked areas of the film; and in the masked areas, exposing at least the sacrificial photoresist layer to solvent such that the sacrificial photoresist layer and any layers above release from the underlying film, thereby providing the film with the patterned material thereon.

[0026] During the solvent exposure step, it will be appreciated that the sidewalls of sacrificial photoresist layer and overlying photoresist layer are exposed to solvent, and at least the sacrificial photoresist layer is solubilised from its edges, such that the overlying “stack” of layers are lifted off from the underlying film, and without leaving behind PR residues on the film.

[0027] According to a second aspect, the present invention provides a film disposed on a support and having a patterned material thereon, and when produced by the method according to the first aspect.

[0028] According to a third aspect, the present invention provides a layered structure comprising a support, a film disposed on the support, a sacrificial photoresist layer disposed on the film, and an overlying photoresist layer disposed on the sacrificial photoresist layer, the sacrificial photoresist layer adapted to be soluble in resist developer (either before or afterexposing to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left.

[0029] According to a fourth aspect, the present invention provides a method for making the layered structure of the third aspect, comprising: providing the support having the film disposed thereon; providing the sacrificial photoresist layer disposed on the film; and providing the overlying photoresist layer disposed on the sacrificial photoresist layer.

[0030] According to a fifth aspect, the present invention provides use of a sacrificial photoresist layer and an overlying photoresist layer in a method of producing a patterned material disposed on a film, the film being disposed on a support.

[0031] According to a sixth aspect, the present invention provides use of a sacrificial photoresist layer in a method of substantially avoiding or avoiding the presence of PR residues on the film disposed on a support and at the interface between the patterned material and the film layer disposed on a support. The sacrificial photoresist layer is adapted to be soluble in resist developer (either before or after exposing to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left.

[0032] According to a seventh aspect, the present invention provides a method for substantially avoiding or avoiding the presence of PR residues on a film having a patterned material on, and PR residues at the interface between the patterned material and the film layer on a support. The method comprising the steps of: providing a layered structure comprising a sacrificial photoresist layer disposed on the film, and an overlying photoresist layer disposed on the sacrificial photoresist layer, the sacrificial photoresist layer adapted to be soluble in resist developer (either before or after exposing to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left; patterning the overlying photoresist layer and the sacrificial photoresist layer to produce masked and un-masked areas of the film layer; depositing a material on at least the un-masked areas of the film; andin the masked areas, exposing the sacrificial photoresist layer to solvent such that the sacrificial photoresist layer and any layers above release from the underlying film, thereby providing the film with the patterned material thereon.

[0033] It will be appriated that the purpose of the sacrificial photoresist layer is to facilitate the removal of the PR residues. The sacrificial photoresist layer avoids the presence of residues from the overlying photoresist layer on the film because the presence of the sacrificial photoresist layer means that the overlying photoresist layer does not come into direct physical contact with the film. Additionally, the sacrificial photoresist layer is adapted to be releasable from the underlying film upon exposure to a solvent, and such that the presence of PR residues on the film is substantially avoided or reduced. The sacrificial photoresist layer may be adapted to be soluble in resist developer (either before or after exposure to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left. In one embodiment, the sacrificial photoresist layer is P-PR pre-softened by UV (or DUV, EUV), enabling its solubility in the developer and thus allowing it to function as the sacrificial photoresist layer.

[0034] Layered structure

[0035] The layered structure comprises a support, a film disposed on the support, a sacrificial photoresist layer disposed on the film, and an overlying photoresist layer disposed on the sacrificial photoresist layer, each of which is discussed in more detail as follows.

[0036] The support layer

[0037] In some embodiments, the support is formed from a relatively rigid material, which may be selected from the group consisting of semiconductors, metals, and insulators, such as oxides, fluorides, nitrides, arsenides, carbides, diamond, glass, and their combination. However, it will be appreciated by the skilled addressee that other types of rigid support materials would be suitable.

[0038] Examples of rigid supports include:• Semiconductors: such as Si, Ge, InP, ZnO, CdTe, PbTe, AIN, InGaP, Copper Indium Gallium Selenide (CIGS)• Metals: such as Au, Ag, Cu, Pt, Ti• Oxides: such as SiO2, AI2O3, SrTiOs, BaTiOs, BiFeOs, TiO2, SrRuOs, LaAIOs, Ga2OsFluorides: such as CaF2, MgF2Nitrides: such as SisN^ GaN• Arsenides: such as GaAs• Carbides: such as SiC• Diamond: such as c-diamond• Glass: such as borosilicate glass and soda-lime glass

[0039] In some embodiments, the support is a more flexible material, such as a polymer. Preferred polymers may be chosen from: polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethylene (PE), polycarbonate (PC), polypropylene (PP), polyether ether ketone (PEEK), polyarylate (PAR), polyethylene terephthalate glycol-modified (PETG), polydimethylsiloxane (PDMS), or their combination and more. However, it will be appreciated by the skilled addressee that other types of polymer materials would be suitable.

[0040] A further example of a flexible support is a metal foil such as Cu or Al. A further example of a flexible support is ultrathin glass. A further example of a flexible support is mica.

[0041] The thickness of the support is not particularly limited. For example, the thickness of the support may be about 1 , 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, or 1000 nm. The thickness of the support may be about 1 , 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, or 1000 micrometers. The thickness of the support may be about 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10 or more mm.

[0042] The support may include germanium, silicon germanium or other suitable semiconductor material, such as diamond, silicon carbide or gallium arsenic. The support may further include additional features and / or material layers, such as various isolation features formed in the support. The support may include various p-type doped regions and / or n-type doped regions configured and coupled to form various devices and functional features. All doping features may be achieved using a suitable process, such as ion implantation in various steps and techniques. The support may include other features, such as a shallow trench isolation (STI).

[0043] The support may further include various material layers, such as metal-gate-stack material layers. A high-K dielectric material layer may be formed on the support. The high-K dielectric material layer is formed by a suitable process such as an atomic layer deposition (ALD). Other methods to form the high-K dielectric material layer include metal organicchemical vapor deposition (MOCVD), physical vapor deposition (PVD), UV-Ozone Oxidation and molecular beam epitaxy (MBE). In one embodiment, the high-K dielectric material includes AhOx, HfOx. Alternatively, the high-K dielectric material layer includes metal nitrides, metal silicates, complex oxides, or other metal oxides.

[0044] The film layer

[0045] In preferred embodiments of the present invention the film comprises a semiconductor material, and in other embodiments the film is not a semiconductor material. Preferred materials of the film are selected from the group consisting of: graphene, transition metal dichalcogenides [e.g., molybdenum disulfide (M0S2), tungsten diselenide (WSe2), tungsten disulfide (WS2)], transition metal carbides and nitrides (MXenes), black phosphorus, boron nitride, arsenide, antimonide, telluride, silicene, germanene, phosphorene, borophene, stanene, bismuthene, indium selenide (InSe), gallium selenide (GaSe), tin selenide (SnSe), indium sulfide (InS), gallium sulfide (GaS), tin sulfide (SnS), indium telluride (InTe), gallium telluride (GaTe), tin telluride (SnTe), black arsenic phosphorus (b-AsP), bismuth oxyselenide (Bi2O2Se), oxides (e.g. Ga2Os, LaAIOs, SrTiOs, etc.), and other materials like diamond, SiC, GaN, GaAs scaled down to membranes, and more. In one embodiment, the film comprises a semiconductor material, which can be used as a channel material.

[0046] Examples of channel materials include: graphene, transition metal dichalcogenides (TMDCs) - e .g., molybdenum disulfide (M0S2), tungsten diselenide (WSe2), tungsten disulfide (WS2), etc.; transition metal carbides and nitrides (MXenes), black phosphorus (phosphorene), arsenene, antimonene, silicene, germanene, phosphorene, borophene, stanene, antimoene, bismuthene, tellurene, indium selenide (InSe), gallium selenide (GaSe), tin selenide (SnSe), indium sulfide (InS), gallium sulfide (GaS), tin sulfide (SnS), indium telluride (InTe), gallium telluride (GaTe), tin telluride (SnTe), oxides - e.g., Bi2O2Se, Ga2Os, etc.; and ultra-thin materials like diamond, SiC, GaN, GaAs, and more.

[0047] In some preferred embodiments, the 2D layered material can be graphene or transition metal dichalcogenide (TMDc) film, or others. The term "chalcogenides" includes dichalcogenides, trichalcogenides, and does not preclude chalcogenides having more than one chalcogen atom. Moreover, the dichalcogenide has a composition generally represented by a formula, MX2, where M is a metal, and X is a chalcogen such as sulfur, selenium, tellurium, and the combination thereof, and the chalcogens are not limited to the examples provided herein. For example, the 2D layered semiconductor can be transition metal dichalcogenides (TMDs), I ll-VI compound semiconductors, or ll-VI compound semiconductors. The transition metal dichalcogenides can be M0S2, MoSe2, MoTe2, HfS2, HfSe2, HfTe2, WS2, WSe2, WTe2,NbS2, NbSe2, NbTe2, ReS2, ReSe2, ReTe2, and so on. The I ll-VI compound semiconductors may be GaS, GaSe, GaTe, or ln2Se3. The IV-VI compound semiconductors may be GeSe.

[0048] In some preferred embodiments of the present invention, the film is a 2D layered semiconductor, which is preferably a transition metal dichalcogenide film.

[0049] In one embodiment, the film is homogenous. However, in other embodiments the film comprises two or more sublayers (e.g. 2, 3, 4, 5, or more), that may be a heterostructure, meaning it can consist of a stack of two or more different material layers. One example of a heterostructure is LaAIOs / SrTiOs, which can generate an electron transport layer at their interfaces, making it promising for use in electronics. Another example is MoS2 / WSe2, which forms a p-n junction. A further example is h-BN / WSe2 / h-BN, which forms a quantum well. Some examples of heterostructures can be seen in Figure 7.

[0050] It will be appreciated that the film, which eventually has a patterned material on it, is disposed on the support.

[0051] Preferably the thickness of the film is from about 0.3 nm to about 10 .m, for example from about 0.5 nm to about 10 .m, for example from about 0.3 nm to about 5 .m, for example from about 0.3 nm to about 3 .m, for example from about 0.3 nm to about 1 .m, for example from about 0.3 nm to about 500 nm, for example from about 0.3 nm to about 100 nm, for example from about 0.3 nm to about 50 nm. The film thickness may be atomically thin, for example 0.35 to 0.75 nanometres (3.5 x 10"10m to 7.55 x 10"10m), or may be 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000 nm, or more thick.

[0052] The sacrificial photoresist layer

[0053] As described above, the present invention provides a layered structure comprising a sacrificial photoresist layer disposed on the film (which is disposed on the support), and an overlying photoresist layer disposed on the sacrificial photoresist layer. The sacrificial photoresist layer is adapted to be soluble in resist developer (either before or after exposing to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left. In one embodiment, the sacrificial protection layer may be a single layer having these properties. In an alternative embodiment, the sacrificial protection layer may be a plurality of layers that each have properties which, when combined, mean that the sacrificial photoresist layer overall is soluble in resist developer (either before or after exposing to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left.

[0054] In one embodiment, the overlying photoresist layer is formed from an N-PR layer, and the sacrificial photoresist layer is a “softened” P-PR layer. The sacrificial photoresist layer may be “softened” by UV (or DUV, EUV) to enable its solubility in the developer, allowing it to function as the sacrificial photoresist layer. The P-PR layer may be homogenous, or may comprise two or more sublayers (e.g. two, three, four or five).

[0055] Softened (P-PR) layer

[0056] The “softened” P-PR layer (sacrificial photoresist layer) may comprise a main polymer resin (e.g., phenolic resin) and a photoactive compound (PAC), (e.g., naphtoquinone diazide (NQD)), but will not include crosslinkers.

[0057] Commercial photoresists functioning as the “softened” P-PR layer include AZ 1500 Serie, AZ ECI 3000 Serie, and more.

[0058] The thickness of P-PR layers is from about 20 nm to about 20 .m, for example from about 20 nm to about 10 .m, for example from about 100 nm to about 3 .m, for example from about 100 nm to about 20 .m, for example from about 500 nm to about 20 .m, for example from about 1 .m to about 10 .m.

[0059] Developers and solvents for the sacrificial photoresist layer

[0060] As discussed above, the sacrificial photoresist layer is adapted to be soluble in resist developer with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left. The sacrificial photoresist layer is adapted to be soluble in resist developer with minimized residues either before or after exposing to UV.

[0061] A developer is a chemical solution used to selectively remove parts of a lightsensitive photoresist after it has been exposed to light. It selectively removes the exposed parts of P-PR. The choice of developer solution depends upon the chosen of photoresists. In one embodiment, the developer is an aqueous solution optionally comprising a surfactant. In one embodiment, use of the developer is followed by a rinse using water. The specific parameters (e.g. time, solvents, temperature) for the development step depend upon the chosen photoresist.

[0062] The solvent to release the sacrificial photoresist layer may be acetone, or other fluids that would dissolve or swell the sacrificial photoresist layer and yet not damage the underlying film, or leave residue on the underlying film. Preferably the solvent is an organic solvent, or a mixture of two or more organic solvents, selected from the group consisting of: ketone solvents, and alcohols. One preferred solvent is a mixture of acetone and isopropylalcohol (I PA). It will be appreciated that the solvent, or solvent system, is chosen to be suitable for the sacrificial photoresist layer such that the sacrificial photoresist layer is soluble or swellable in that solvent, such that the sacrificial photoresist layer can be removed from the underlying film and leaves no residue on the film, and does not damage the film.

[0063] The photopatternable material / overlying photoresist layer

[0064] The overlying photoresist layer is formed from a photopatternable material which is selected from the group consisting of: a photoresist comprising the main polymer resin, a photoactive compound (PAC), or a photoresist comprising the main a polymer resin, a photoinitiator, and a cross-linking agent. Photopatternable materials that are well-known in the art may be used in the present invention.

[0065] In some embodiments the overlying photoresist layer is produced by coating a photoresist on the sacrificial photoresist layer, exposing the photoresist layers, and developing the photoresist layers, resulting in the patterned photoresist layers to thereby produce the masked and un-masked areas of the layered structure. An exemplary photolithography process may include processing steps of photoresist coating, soft baking, mask aligning, exposing, post-exposure baking, developing photoresist and hard baking. The lithography process may implement ultraviolet lithography, deep ultraviolet lithography, extreme ultraviolet lithography (EUV), and others.

[0066] It will be appreciated by a skilled person that there are two types of photoresists, positive and negative, i.e. , P-PR and N-PR, respectively. Positive photoresists become more soluble when exposed to light, allowing the exposed areas to be washed away. Negative photoresists become less soluble when exposed to light, causing the exposed areas to remain while the unexposed areas are washed away. Commercial positive photoresists include AZ® 1500 Serie and AZ® ECI 3000 Serie. Commercial negative photoresists include AZ® nLOF 2000 Serie. Other commercially available photoresists will be known to the skilled addressee.

[0067] The thickness of each of the photoresist layers is from about 20 nm to about 20 .m, for example from about 20 nm to about 10 .m, for example from about 100 nm to about 3 .m, for example from about 100 nm to about 20 .m, for example from about 500 nm to about 20 .m, for example from about 1 .m to about 10 .m.

[0068] Layer deposition processes

[0069] The layers described herein (e.g., the film disposed on the support, the overlying photoresist layer disposed on the sacrificial photoresist layer, etc) may be disposed on an underlying layer by processes that are well known in the art.

[0070] By way of example only, the film may be disposed on the support by a thin film growth technique, or thin film transfer technique, or the combination of both.

[0071] By way of further example only, the photoresist layers may be disposed on the film (or each other) by coating or printing.

[0072] By way of further example only, the photoresist may be disposed on an underlying layer by spin-coating, dip coating or printing including slot die printing, screen printing inkjet printing and roller printing and more. The coated sample may be gently heated to evaporate the solvent and solidify the photoresist layer (i.e., “soft bake”). The sample may then be exposed to ultraviolet light (or EUV, DUV), depending on the photoresist type. The light alters the solubility of the exposed areas, i.e., an exposure step. Optionally, it may be possible to undertake a “hard bake” for N-PR, for further hardening the photoresist. The sample is immersed in a developer solution that selectively dissolves the exposed (P-PR) or unexposed (N-PR) areas of the photoresist, followed by rinse to remove residual developer and dried, i.e. a development step. Optionally it may be possible to expose the sample to a higher temperature bake to further harden the remaining photoresist and improve its adhesion and etch resistance, i.e. an optional final baking step. Finally, the patterned photoresist serves as a mask for subsequent etching (removal of exposed material) or deposition (adding new material) processes to create the desired microstructures.

[0073] Patterning step and removal

[0074] The patterning comprises UV (or DUV, EUV) exposure of selected areas of the overlying photoresist layer. This type of patterning may be referred to as photopatterning. This a technique which is conventional in the art and with which the skilled person is familiar. The pattern can be stripes, grid pattern, and any geometric shapes patternable by photoresist.

[0075] When the overlying photoresist layer is N-PR, the masked areas of the layered structure are defined by areas of the overlying N-PR which have been exposed to UV and which are consequently insoluble in a developer. When the overlying photoresist layer is P- PR, the masked areas of the layered structure are defined by areas of the overlying P-PR which have not been exposed to UV and are consequently insoluble in a developer.

[0076] The preferred wavelength for UV exposure depends upon the choice of photoresist and may be from extreme UV (EUV) to UV (g-line).

[0077] The preferred intensity for UV exposure depends upon the choice of photoresist and its thickness.

[0078] One example: AZ® nLOF 2000 Serie (N-PR), 365 nm sensitive, dose applied: 150 mJ / cm2(upon the as-coated thickness).

[0079] The selective removal step preferably comprises use of a developer. The choice of developer solution depends upon the chosen of photoresists. In one embodiment, the developer is an aqueous solution optionally comprising a surfactant. In one embodiment, use of the developer is followed by a rinse using water. The specific parameters (e.g. time, solvents, temperature) for the development step depend upon the chosen photoresist.

[0080] One example: when developing AZ® nLOF 2000 Serie (N-PR), using commercial developers, such as AZ MIF Developers series. Dip the sample in developer for 40 s- 60 s, followed by deionised water rinse.

[0081] One example: when developing a stack comprising AZ® 1500 Serie (P-PR) as the sacrificial photoresist layer and AZ® nLOF 2000 Serie (N-PR) as the overlying photoresist layer, using commercial developers, such as AZ® 726, a TMAH-based developer (0.2610 ± 0.0005 moles / l TMAH(TetraMethylAmmoniumHydroxide) in H2O with surfactants added) for 1 min under room temperature, followed by deionised water rinse.

[0082] Material

[0083] In one embodiment, the material is homogenous. In another embodiment, the material comprises two or more sublayers (e.g. two, three, four, five or more).

[0084] In one embodiment, the material is electrode material. The electrode material is optionally a metal or an alloy.

[0085] In one embodiment, the material is a metal, e.g. Ag, Al, Au, Co, Cr, Cu, Fe, Ge, Ir, Nb, Ni, Pd, Pt, Si, Sn, Ti.

[0086] In one embodiment, the material is an alloy, e.g. NbTi, AuGe, PdAu, NiFe.

[0087] In one embodiment, the material is an oxide, e.g. SiOx, AI2OX, SrTiOs, LaAIOs, BaTiOs, BiFeOs, TiO2. Oxides can be deposited by physical vapour deposition or chemicalvapour deposition with the temperature under the tolerance of photoresist (less than 350 °C), such as SiOx, AhOx.

[0088] In one embodiment, the material is a fluoride, such as CaF2 or MgF2.

[0089] Preferably, the material is a metal or an alloy.

[0090] Preferably the thickness of the patterned material layer is less than 30% of the total combined thickness of the sacrificial photoresist layer and the overlying photoresist layer layers.

[0091] Depositing a material

[0092] Deposition of the material via a technique which is conventional in the art and with which the skilled person is familiar. In one embodiment, the material is deposited by a physical vapor deposition (PVD) method. Examples of physical vapor deposition methods include pulsed laser deposition (PLD), molecular-beam epitaxy (MBE), oxide molecular-beam epitaxy (OMBE), RF or DC magnetron sputtering deposition, thermal evaporation, electron beam evaporation, arc vapour deposition, ion plating, reactive PVD and others. In one embodiment, the material is deposited by a chemical vapor deposition (CVD) method. Examples of chemical vapor deposition methods include cold- or hot-wall CVD, atomic layer deposition (ALD), metal organic CVD on (MOCVD), thermal CVD, plasma-enhanced CVD (PECVD), photo-enhanced CVD (photo-CVD), low-pressure CVD (LPCVD), high-pressure CVD (HPCVD), laser-assisted CVD (LCVD), atmospheric pressure CVD and others.

[0093] Exposure to solvent and release of sacrificial photoresist layer

[0094] Exposure of the masked areas of the sacrificial photoresist layer to solvent facilitates release of the masked areas of the sacrificial photoresist layer (and layers above it) from the underlying film, thereby providing the film with the patterned material thereon. This can be referred to as “solvent lift-off”. The solvent selected is preferably a solvent which does not cause damage to the film or cause the film to peel off the support.

[0095] The solvent used in this step is suitably an organic solvent or a mixture of two or more organic solvents (e.g. two, three, four or five). Examples of solvents include, but are not limited to, ketone solvents and alcohols. A further example of a solvent is dimethylsulfoxide (DMSO).

[0096] Examples of ketone solvents include acetone, cyclohexanone, diisobutyl ketone (DIBK), methyl ethyl ketone and methyl isobutyl ketone.

[0097] Examples of alcohol solvents include methanol, ethanol, propanol, isopropyl alcohol (I PA), butanol and isobutanol.

[0098] Examples of mixtures of solvents include a mixture of one or more ketone solvents (e.g. one, two or three) and one or more alcohol solvents (e.g. one, two or three), a mixture of two or more ketone solvents (e.g. two, three or four) and a mixture of two alcohol solvents (e.g. two, three or four). Examples of mixtures of two solvents include a mixture of a ketone solvent and an alcohol solvent, a mixture of two ketone solvents and a mixture of two alcohol solvents.

[0099] Preferred solvents for this step are selected from the list consisting of acetone and isopropyl alcohol (I PA) and mixtures thereof.[000100] This step is optionally carried out at room temperature and at atmospheric pressure.[000101] The time for this step is optionally from 1 to 60 minutes. The duration of this step can be modified based on the need of the processing.[000102] Softening of the sacrificial photoresist layer[000103] In one embodiment, the sacrificial photoresist layer is P-PR layer and developed at the same time with the overlying photoresist layer to show lithography patterns.[000104] The P-PR layer exhibits the characteristic of becoming soluble to the photoresist developer after exposure to light. Thus, the P-PR layer is softened by exposing the whole surface of the P-PR layer to UV (or DUV, EUV) light that has a wavelength that the photoresist is sensitive to. Similar to the standard lithography processes, mainstream lithography tools, can be used for this step.[000105] The preferred wavelength for lithography depends upon the choice of photoresists and may be from extreme UV (EUV) to UV (g-line).[000106] One example: AZ® 1500 Serie (P-PR), 365 nm sensitive, dose applied: 150 m J / cm2(upon the as-coated thickness).[000107] An example of a method of UV pre-treatment is described by Mertens, P. W., et al. "Challenges and novel approaches for photo resist removal and post-etch residue removal for 22 nm interconnects." 2009 IEEE International Interconnect Technology Conference. IEEE, 2009.[000108] The softened P-PR layer is removable by use of a solvent in the step of releasing the masked areas of the sacrificial photoresist layer (and layers above it) from the underlying film.[000109] Use of the sacrificial photoresist layer[000110] The invention provides use of a sacrificial photoresist layer in a method of substantially avoiding or avoiding the presence of PR residues on the film layer, said film having a patterned material on its surface, and substantially avoiding or avoiding the presence of PR residues on the film or at the interface between the patterned material and the film.[000111] Use of the sacrificial photoresist layer avoids the presence of residues from the overlying photoresist layer on the film because the presence of the sacrificial photoresist layer means that the overlying photoresist layer does not come into direct physical contact with the film.[000112] The sacrificial photoresist layer is selected such that the overlying photoresist layer and the sacrificial photoresist layer can be patterned in lithography development in the same step.[000113] The sacrificial photoresist layer is selected such that masked areas of the sacrificial photoresist layer can be removed by solvent in a process which facilitates release of the sacrificial photoresist layer from the film and which does not cause damage to the film or cause the film to peel off the support.[000114] The sacrificial photoresist layer preferably leaves behind little or no PR residues on the film after exposure to solvent to facilitate release of the sacrificial photoresist layer. Therefore, the presence of PR residues on the film is substantially avoided or avoided.[000115] Uses of the patterned films as disclosed herein[000116] In one preferred embodiment, the patterned film disposed on the support is a part of a field-effect transistor (FET), such as a 2D-FET. Other embodiments will be known to the skilled addressee.[000117] The present disclosure is not limited to applications in which the semiconductor structure includes a FET, and may be extended to other micro / nano-electronic devices having semiconductors, metals and insulators where deposited materials on the film are needed to be patterned. For example, the semiconductor structure may include a dynamic random access memory (DRAM) cell, a single electron transistor (SET), and / or other micro / nano-electronicdevices (collectively referred to herein as micro / nano-electronic devices). Of course, aspects of the present disclosure are also applicable and / or readily adaptable to other types of transistors, such as gate-all-around transistors, and other types of micro / nano-electronic devices employed in many different applications, including optoelectronics, spintronics and others.DEFINITIONS[000118] In describing and claiming the present invention, the following terminology will be used in accordance with the definitions set out below. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments of the invention only and is not intended to be limiting.[000119] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one having ordinary skill in the art to which the invention pertains.[000120] Unless the context clearly requires otherwise, throughout the description and the claims, the terms “comprise”, “'comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”. For example, a composition, mixture, process or method that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, mixture, process or method.[000121] The transitional phrase "consisting of” excludes any element, step, or ingredient not specified. If in the claim, such would close the claim to the inclusion of materials other than those recited except for impurities ordinarily associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim, rather than immediately following the preamble, it limits only the element set forth in that clause; other elements are not excluded from the claim as a whole.[000122] The transitional phrase "consisting essentially of" is used to define a composition, process or method that includes materials, steps, features, components, or elements, in addition to those literally disclosed, provided that these additional materials, steps, features, components, or elements do not materially affect the basic and novel characteristic(s) of the claimed invention. The term "consisting essentially of" occupies a middle ground between "comprising" and "consisting of'.[000123] Where the applicant has defined an invention or a portion thereof with an open- ended term such as "comprising", it should be readily understood that (unless otherwise stated)the description should be interpreted to also describe such an invention using the terms "consisting essentially of" or "consisting of." In other words, with respect to the terms “comprising”, “consisting of”, and “consisting essentially of”, where one of these three terms is used herein, the presently disclosed and claimed subject matter may include the use of either of the other two terms. Thus, in some embodiments not otherwise explicitly recited, any instance of “comprising” may be replaced by “consisting of” or, alternatively, by “consisting essentially of’.[000124] While reference may be made in this disclosure to the invention comprising a combination of a plurality of elements, it is also understood that this invention is regarded to comprise combinations which omit or exclude one or more of such elements, even if this omission or exclusion of an element or elements is not expressly stated herein, unless it is expressly stated herein that an element is essential to the applicant' s combination and cannot be omitted. It is further understood that the related prior art may include elements from which this invention may be distinguished by negative claim limitations, even without any express statement of such negative limitations herein. It is to be understood, between the positive statements of applicant's invention expressly stated herein, and the prior art and knowledge of the prior art by those of ordinary skill which is incorporated herein even if not expressly reproduced here for reasons of economy, that any and all such negative claim limitations supported by the prior art are also considered to be within the scope of this disclosure and its associated claims, even absent any express statement herein about any particular negative claim limitations.[000125] As used herein, with reference to numbers in a range of numerals, the terms "about," "approximately" and "substantially" are understood to refer to the range of -10% to +10% of the referenced number, preferably -5% to +5% of the referenced number, more preferably -1 % to + 1 % of the referenced number, most preferably -0 .1 % to +0 .1 % of the referenced number. Moreover, with reference to numerical ranges, these terms should be construed as providing support for a claim directed to any number or subset of numbers in that range. For example, a disclosure of from 1 to 10 should be construed as supporting a range of from 1 to 8, from 3 to 7, from 1 to 9, from 3.6 to 4.6, from 3.5 to 9.9, from 8 to 10, and so forth.[000126] The terms “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention.[000127] The complete disclosures of the patents, patent documents and publications cited herein are incorporated by reference in their entirety as if each were individually incorporated.[000128] Unless expressly stated to the contrary, "or" refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).[000129] The term "and / or" used in the context of "X and / or Y" should be interpreted as "X," or "Y," or "X and Y." Similarly, "at least one of X or Y" should be interpreted as "X," or "Y," or "both X and Y."[000130] The indefinite articles "a" and "an" preceding an element or component of the invention are intended to be non-restrictive regarding the number of instances (i.e., occurrences) of the element or component. Therefore "a" or "an" should be read to include one or at least one, and the singular word form of the element or component also includes the plural unless the number is obviously meant to be singular.[000131] As used herein, wt.% refers to the weight of a particular component relative to total weight of the referenced composition.[000132] It will be understood that use of the term “between” herein when referring to a range of numerical values encompasses the numerical values at each endpoint of the range. For example, a temperature of between 80 °C and 150 °C is inclusive of a temperature of 80 °C and a temperature of 150 °C.[000133] Various features of the embodiments of the invention disclosed herein are, for brevity, described in the context of a single embodiment, but may also be provided separately or in any suitable sub-combination. All combinations of the embodiments are specifically embraced by the illustrative embodiments disclosed herein just as if each and every combination was individually and explicitly disclosed. In addition, all sub-combinations listed in the embodiments describing such variables are also specifically embraced by the present compositions and are disclosed herein just as if each and every such sub-combination was individually and explicitly disclosed herein.[000134] In the foregoing paragraphs, where various ratios of components have been disclosed. It will be appreciated that these ratios of components can be combined in any disclosed combination. For example, the ratio of A:B (which may be between about 100:1 and 1 :100 or any range therein), may be combined with the ratio of C:D (which may be betweenabout 50:1 and 1 :50 or any range therein), and may be combined with the ratio of E:F (which may be between about 10:1 and about 1 :10 or any range therein).[000135] The term “photopattern” refers to exposure of areas of a surface to UV (or DUV, EUV) light. A mask (either a physical mask or a digital mask) is used to partially block the UV (or DUV, EUV) light and thereby selectively expose areas of the surface to the UV (or DUV, EUV) light. Photopatternable refers to a photoresist which undergoes a chemical change on exposure to UV light.[000136] Negative photoresist (N-PR) is photocurable and becomes insoluble in developer after exposure to UV (or DUV, EUV). Positive photoresist (P-PR) becomes soluble in developer after exposure to UV (or DUV, EUV).[000137] Wet etching is a process wherein a chemical or etchant is used to remove parts of material in the etching process. Dry etching is a process wherein gases and plasma are used to achieve the same goal, i.e. , to remove parts of material.[000138] A dielectric material is a non-metallic material having a high specific resistance, a negative temperature coefficient of resistance and a high insulating resistance.[000139] A channel material is a material for conveying electrical or electromagnetic signals.[000140] It will be understood that relative terms such as "above", "below", "top", "bottom", "above" and "below" when used herein may be used to describe various elements relative to each other. These relative terms are intended to encompass different orientations of the elements in addition to the orientation depicted in the figures.BRIEF DESCRIPTION OF THE DRAWINGS[000141] The aspects described above, as well as other apparent aspects, advantages, and objectives of the present invention are apparent from the detailed description below in combination with the drawing, in which:[000142] Figure 1 is a graphical step-by-step representation of the novel and inventive method disclosed herein. The inventive method is described in Figure 1 as “Use of P / N-PR”. The methods described as “Use of N-PR” and “Use of P-PR” are included as the conventional methods for comparative purposes.[000143] Figure 2 shows the analysis of PR residues on M0S2 experiencing photoresist mask patterning processes, (a-c) The AFM topography of (a) the as-grown M0S2 sample (the reference sample), (b) M0S2 after deposited materials on it by the method in the presentinvention (P / N-PR), and (c) M0S2 after deposited materials on it by the conventionally used method, i.e., using N-PR to form the patterned photoresist mask for subsequent deposition. All images show 1 pm by 0.5 pm areas with identical colour scale bars from -2 nm to 2 nm. (d) The comparison of FTIR spectra acquired from the three samples. The blue (solid square), red (shiny dot), and green (open diamond) lines represent the samples in (a-c), respectively. The top inset shows a zoom-out of the full-range spectra, (e) PL spectra for comparing PR-residue- imposed effects on M0S2.[000144] Figure 3 shows the electrical performance of M0S2 FET arrays fabricated using the present invention (P / N-PR) and M0S2 FET arrays fabricated using the conventional method, i.e., using N-PR to form the patterned photoresist mask for subsequent deposition, (a) Total resistances (source-to-drain, without applying gate voltages) verse channel lengths, (b) Statistical comparison of important metrics collected from M0S2 FET arrays fabricated by the two different methods.[000145] Figure 4 shows the typical transfer characteristics (IDS-VG) collected from M0S2 FETs fabricated using the present invention (P / N-PR, red shiny dots) and M0S2 FETs fabricated using the conventional method, i.e., using N-PR to form the patterned photoresist mask for subsequent deposition (green squares). These FETs employ 40-nm AI2O3 as top gates.[000146] Figure 5 shows the pattern results of materials deposition achieved through different solvent lift-off processes using P-PR and N-PR photoresist masks, respectively. The upper panel shows the overcut sidewalls generated due to the nature of P-PR, impairing the successful lift-off. The lower panel shows the undercut sidewalls generated due to the nature of N-PR, facilitating the successful lift-off. The left two images are the cross-section schematic illustration for presenting the difference between the P-PR and N-PR in solvent lift-off processes. The right two optical images compare the typical lift-off results obtained by P-PR and N-PR. The scale bar: 200 pm.[000147] Figure 6 shows the scanning electron microscope (SEM) images of the crosssections of the photoresist masks on silicon substrates after lithography and PR development, (a) N-PR and (b) the P / N-PR. The scale bar is 10 pm.[000148] Figure 7 shows some examples of a film comprising heterostructures and sublayers.DETAILED DESCRIPTION[000149] The skilled addressee will understand that the invention comprises the embodiments and features disclosed herein as well as all combinations and / or permutations of the disclosed embodiments and features.[000150] Methods of making a layered material[000151] In one example, the support can be cut from a three-dimensional (3D) bulk crystal.[000152] In one example, the film is provided on the support by a thin film growth technique, or thin film transfer technique, or the combination of both. Examples of thin film growth techniques for providing the film on the support include chemical vapour deposition (CVD), such as cold- or hot-wall CVD, atomic layer deposition (ALD), metal organic CVD on (MOCVD), thermal CVD, plasma-enhanced CVD (PECVD), photo-enhanced CVD (photo-CVD), low- pressure CVD (LPCVD), high-pressure CVD (HPCVD), laser-assisted CVD (LCVD), atmospheric pressure CVD and others, and physical vapour deposition (PVD), such as pulsed laser deposition (PLD), molecular-beam epitaxy (MBE), oxide molecular-beam epitaxy (OMBE), RF or DC magnetron sputtering deposition, thermal evaporation, electron beam evaporation, arc vapour deposition, ion plating, reactive PVD and others.[000153] Techniques of thin film transfer are conventional in the art. These techniques have the potential to be used in very large-scale integration (VLSI) technology at either the front or back end of line-through monolithic or heterogeneous integration. Examples of combinations of thin film growth techniques and thin film transfer techniques for providing the film layer on the substrate (or support) include transferring a thin film onto the substrate (or support) followed by growing additional materials on the transferred thin film to form the film layer, or, growing a thin film onto the substrate followed by transferring additional materials on the as- grown thin film to form the film layer.[000154] In one embodiment, the photoresist layer can be provided by coating or printing. Other coating techniques are also feasible, such as dip coating, or thin film printing including slot die coating and roller printing. These are techniques which are conventional in the art and with which the skilled person is familiar.EXAMPLES[000155] The present invention will now be described with reference to the following examples which should be considered in all respects as illustrative and non-restrictive.[000156] EXAMPLE 1[000157] An example according to the invention is as follows:[000158] FURTHER EXAMPLES[000159] Significantly fewer PR residues are left by the method of the present invention (P / N- PR) on the M0S2 surface, as can be evidenced by atomic force microscopy (AFM) and Fourier- transform infrared (FTIR) spectroscopy, where the amount of residue left on the M0S2 can be directly characterised by the surface roughness and peak intensity, respectively. Figure 2 (a-c) shows the AFM topography of the reference sample (as-grown M0S2), the M0S2 after P / N-PR, and M0S2 after N-PR, from left to right, where the as-measured surface roughnesses are 0.099 nm, 0.282 nm, and 0.566 nm, respectively. The increased roughness intuitively demonstrates that the N-PR method induces severe PR residues on M0S2, compared to the PR residues induced by the P / N-PR method. In Figure 2 (d), which are FTIR spectra, the broad bands from 675 cm-1to 775 cm-1are obtained from M0S2 after experiencing photoresist mask patterning processes ready for subsequent deposition, but are absent in the reference sample, evidencing that the bands are induced by fabrication processes. The ranges cover multiple peaks, such as peaks at 720 cm-1and 730 cm-1, in line with the peaks of C-H rocking induced by the PR residues. In Figure 2 (d), the significantly quenched broadband in P / N-PR verifies the reduced PR residues, compared to the stronger signal in spectra of N-PR. Beyond the range, other absorptions, which also exist in the reference sample, can be attributed to M0S2 and the sapphire substrate. The fullrange FTIR spectra shown in Figure 2 (d) top inset demonstrate no detectable differences over 1000 cm'1.[000160] Beyond reducing observed PR residues, the P / N-PR method of the invention can effectively moderate PR-residue-induced property variation of M0S2, as demonstrated by the photoluminescence (PL) spectra shown in Figure 2 (e). Using the reference sample as the benchmark, the M0S2 after experiencing photoresist mask patterning processes by conventionally used N-PR shows a prominent redshift and intensity quench, indicating stronger doping or strain has been imposed on the M0S2. In contrast, the red-line-marked PL spectrum indicates that applying P / N-PR can moderate the property variation.[000161] Figure 3 demonstrates that the present invention can suppress the PR residues- induced device-to-device variation of the M0S2 FET array and enhance FET performance over a large-area wafer scale. Without applying a gate voltage, Figure 3 (a) presents the two-terminal device-to-device variation by statistically plotting source-to-drain resistances of FETs versus channel lengths. It is adapted from transition line measurement (TLM), where the total resistance should fit a straight line if the channel material and contact resistance are considered uniform. Multiple data points are collected from different FETs over the whole array areas to average the variation induced by M0S2 film growth thus giving prominence to the residue-induced influence. From Figure 3 (a), it can be clearly seen that the extracted resistances from the P / N-PR-made FETs (red dots) show a near linear fitting to channel length while the resistances of the devicesmade of N-PR (green squares) are notably scattered. It indicates that using the P / N-PR method can effectively suppress the fabrication-induced device-to-device variation, which can be attributed to the conformal metal deposition for metal contacts, as well as the reduced carrier scattering and trapping on the atomically thin channels.[000162] The present invention is also evidenced to enhance important metrics of the 2D FET arrays. Typical FET benchmarking is measured from these two groups of samples, including subthreshold swing (SS), threshold voltage ( T), and source to drain current (IDS) in Figure 3 (b). The FETs fabricated by P / N-PR techniques show much lower SS, higher ON currents, and more stable VT, suggesting the enhanced FET working speed, lowered contact resistance, and reduced device-to-device variation, respectively. Figure 4 shows several typical transfer characteristics of M0S2 FETs fabricated by P / N-PR and N-PR, to make a direct comparison.[000163] It is demonstrated herein that using only P-PR can cause problems in the lift-off process, for example, resulting in material bridges. As aforementioned, the P-PR tends to generate inappropriate sidewalls after development due to the nature of the P-PR, which prevents the solvent from penetrating to release the P-PR layer from the film after material deposition. The schematic in Figure 5 provides a detailed description of how the penetration blockage occurs, while the comparison of optical images clearly presents the material deposition results of using single-layer P-PR and single-layer N-PR to form the patterned mask.[000164] In contrast, the bilayer P / N-PR stack greatly retains the benefits of using N-PR for achieving correct sidewall profiles essential for subsequent deposition (adding new material) processes and lift-off processes. As demonstrated in Figure 6 (a-b), after development, the typical cross-sections of both the one-layer N-PR and the bilayer P / N-PR show similar inverted trapezoid shapes. The cliff-like sidewalls prevent material covering during the material deposition, thus eliminating the material bridges. The improvement of bilayer P / N-PR can be attributed to the fact that the N-PR plays the role of selective patterning and sidewall retaining, while the P-PR only works as the sacrificial photoresist layer to reduce residues.[000165] In summary, the main goal of using the P / N-PR is to suppress remaining residues on the film layer while enabling the clean lift-off to pattern materials. Beyond this, the invented P / N- PR bilayer is compatible with well-established standard nanofabrication processes without requiring additional facilities. Except for the photoresists and M0S2 thin film used herein, the method is expected to work for other commercial P-PR / N-PRs and other thin film materials. This is promising for the manufacturing of wafer-scaled high-performance 2D electronics and equivalent or similar devices.[000166] EMBODIMENTS OF THE INVENTION[000167] Other embodiments of the invention as described herein are defined in the following paragraphs:1 . A method for producing a patterned material on a film disposed on a support, the method comprising the steps of: providing a layered structure comprising a sacrificial photoresist layer disposed on the film, and an overlying photoresist layer disposed on the sacrificial photoresist layer, the sacrificial photoresist layer adapted to be soluble in resist developer (either before or after exposing to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left, patterning the overlying photoresist layer and the sacrificial photoresist layer to produce masked and un-masked areas of the film layer, depositing a material on at least the un-masked areas of the film; and in the masked areas, exposing at least the sacrificial photoresist layer to solvent such that the sacrificial photoresist layer releases from the underlying film, thereby providing the film with the patterned material thereon.2. A film disposed on a support and having a patterned material thereon, when produced by the method according to according to paragraph 1.3. A layered structure comprising a support, a film disposed on the support, a sacrificial photoresist layer disposed on the film, and an overlying photoresist layer disposed on the sacrificial photoresist layer, the sacrificial photoresist layer adapted to be soluble in resist developer (either before or after exposing to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left,4. A method for making the layered structure according to paragraph 2, the method comprising: providing the support having the film disposed thereon; providing the sacrificial photoresist layer disposed on the film; and providing the overlying photoresist layer disposed on the sacrificial photoresist layer.5. Use of a sacrificial photoresist layer in a method of substantially avoiding or avoiding the presence of PR residues on film disposed on a support and at the interface between the patterned material and the film disposed on a support, the sacrificial photoresist layer adapted to be soluble in resist developer (either before or after exposing to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left, or use of a sacrificial photoresist layer and an overlying photoresist layer in a method of producing a patterned material disposed on a film disposed on a support.6. A method for substantially avoiding or avoiding the presence of PR residues on a film disposed on a support and at the interface between the patterned material and the film disposed on a support, the method comprising the steps of: providing a layered structure comprising a sacrificial photoresist layer disposed on the film, and an overlying photoresist layer disposed on the sacrificial photoresist layer, the sacrificial photoresist layer adapted to be soluble in resist developer (either before or after exposing to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left, patterning the overlying photoresist layer and the sacrificial photoresist layer to produce masked and un-masked areas of the film layer, depositing a material on at least the un-masked areas of the film; and in the masked areas, exposing the sacrificial photoresist layer to solvent such that the sacrificial photoresist layer releases from the underlying film, thereby providing the film with the patterned material thereon.7. The method, the film, the layered structure or the use of a sacrificial photoresist layer according to any one of the preceding paragraphs, wherein the support is a rigid support, optionally selected from the group consisting of semiconductors, metals, and insulators, such as oxides, fluorides, nitrides, arsenides, carbides, diamond, and glass.8. The method, the film, the layered structure or the use of a sacrificial photoresist layer according to any one of the preceding paragraphs, wherein the support is a polymer support, optionally selected from the group consisting of polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethylene (PE), polycarbonate (PC), polypropylene (PP), polyether ether ketone (PEEK), polyarylate (PAR), polyethylene terephthalate glycol-modified (PETG), polydimethylsiloxane (PDMS).9. The method, the film, the layered structure or the use of a sacrificial photoresist layer according to any one of the preceding paragraphs, wherein the film is optionally selected from the group consisting of: graphene, transition metal dichalcogenides [e.g., molybdenum disulfide (M0S2), tungsten diselenide (WSe2), tungsten disulfide (WS2)], transition metal carbides and nitrides (MXenes), black phosphorus, boron nitride, arsenide, antimonide, telluride, silicene, germanene, phosphorene, borophene, stanene, bismuthene, indium selenide (InSe), gallium selenide (GaSe), tin selenide (SnSe), indium sulfide (InS), gallium sulfide (GaS), tin sulfide (SnS), indium telluride (InTe), gallium telluride (GaTe), tin telluride (SnTe), black arsenic phosphorus (b-AsP), bismuth oxyselenide (Bi2O2Se), oxides e.g. Ga2Os, LaAIOs, SrTiOs, etc.; and other materials like diamond, SiC, GaN, GaAs scaled down to membranes, and more.10. The method, the film, the layered structure or the use of a sacrificial photoresist layer according to any one of the preceding paragraphs, wherein the film is a 2Dlayered semiconductor such as a transition metal dichalcogenide film, or is a relatively thicker inorganic membrane formed from Bi2O2Se, Ga2Os or other semiconductor materials.11. The method, the film, the layered structure or the use of a sacrificial photoresist layer according to any one of the preceding paragraphs, wherein the film is homogenous.12. The method, the film, the layered structure or the use of a sacrificial photoresist layer according to any one of the preceding paragraphs, wherein the film comprises two or more sublayers or superlattices.13. The method, the film, the layered structure or the use of a sacrificial photoresist layer according to any one of the preceding paragraphs, wherein the sublayers of the film are optionally selected from the group consisting of graphene, transition metal dichalcogenides [e.g., molybdenum disulfide (M0S2), tungsten diselenide (WSe2), tungsten disulfide (WS2)], transition metal carbides and nitrides (MXenes), black phosphorus, boron nitride, arsenide, antimonide, telluride, silicene, germanene, phosphorene, borophene, stanene, bismuthene, indium selenide (InSe), gallium selenide (GaSe), tin selenide (SnSe), indium sulfide (InS), gallium sulfide (GaS), tin sulfide (SnS), indium telluride (InTe), gallium telluride (GaTe), tin telluride (SnTe), black arsenic phosphorus (b-AsP), bismuth oxyselenide (Bi2O2Se), oxides e.g. Ga2Os, LaAIOs, SrTiOs, etc.; and other materials like diamond, SiC, GaN, GaAs scaled down to membranes, and more, and their superlattices or stacks.14. The method, the film, the layered structure or the use of a sacrificial photoresist layer according to any one of the preceding paragraphs, wherein the sacrificial photoresist layer is softened P-PR, and the overlying photoresist layer is P-PR or N- PR.15. The method, the film, the layered structure or the use of a sacrificial photoresist layer according to any one of the preceding paragraphs, wherein the sacrificial photoresist layer is homogeneous and / or the overlying photoresist layer is homogeneous.16. The method, the film, the layered structure or the use of a sacrificial photoresist layer according to any one of the preceding paragraphs, wherein the sacrificial photoresist layer comprises two or more sub-layers and / or the overlying photoresist layer comprises two or more sub-layers.17. The method, the film, the layered structure or the use of a sacrificial photoresist layer according to any one of the preceding paragraphs, wherein the P-PR comprises a main polymer resin (e.g., phenolic resin) and a photoactive compound (PAC), (e.g., naphtoquinone diazide (NQD)), and the N-PR comprises the main a polymer resin, aphotoinitiator, and a cross-linking agent, or other photopatternable materials that are well known to those skilled in the art may be used in carrying out the present invention.22. The method, the film, the layered structure or the use of a sacrificial photoresist layer according to any one of the preceding paragraphs, wherein the removal step comprises use of a developer.23. The method, the film, the layered structure or the use of a sacrificial photoresist layer according to any one of the preceding paragraphs, wherein the developer is an aqueous solution optionally comprising a surfactant, or other solutions that are well known in the art for use as developers may also be used in the present invention.24. The method, the film, the layered structure or the use of a sacrificial photoresist layer according to any one of the preceding paragraphs, wherein the material is a metal, an oxide, an alloy, or other inorganic material.25. The method, the film, the layered structure or the use of a sacrificial photoresist layer according to any one of the preceding paragraphs, wherein the material is deposited by physical vapor deposition methods including electron beam evaporation, RF magnetron sputtering, DC magnetron sputtering, thermal evaporation, molecular beam epitaxy and chemical vapor deposition methods including atomic layer deposition, molecular organic chemical vapor deposition, and others.26. The method, the film, the layered structure or the use of a sacrificial photoresist layer according to any one of the preceding paragraphs, wherein the solvent comprises an organic solvent or a mixture of two or more organic solvents.[000157] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms, and in particular features of any one of the various described examples may be provided in any combination in any of the other described examples. Various modifications and alterations to this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention. It should be understood that this invention is not intended to be unduly limited by the illustrative embodiments and examples set forth herein and that such examples and embodiments are presented by way of example only with the scope of the invention intended to be limited only by the claims set forth herein as follows.

Claims

CLAIMS1 . A method for producing a patterned material on a film disposed on a support, the method comprising the steps of: providing a layered structure comprising a sacrificial photoresist layer disposed on the film, and an overlying photoresist layer disposed on the sacrificial photoresist layer, the sacrificial photoresist layer adapted to be soluble in resist developer (either before or after exposing to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left, patterning the overlying photoresist layer and the sacrificial photoresist layer to produce masked and un-masked areas of the film layer, depositing a material on at least the un-masked areas of the film; and in the masked areas, exposing at least the sacrificial photoresist layer to solvent such that the sacrificial photoresist layer releases from the underlying film, thereby providing the film with the patterned material thereon.

2. The method of claim 1 , wherein the support is a rigid support, optionally selected from the group consisting of semiconductors, metals, and insulators, such as oxides, fluorides, nitrides, arsenides, carbides, diamond, glass, or their combination.

3. The method of any one of claims 1 to 2, wherein the support is a flexible support, optionally selected from the group consisting of inorganic, organic materials, or their combination and others, such as graphite, mica, polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethylene (PE), polycarbonate (PC), polypropylene (PP), polyether ether ketone (PEEK), polyarylate (PAR), polyethylene terephthalate glycol-modified (PETG), polydimethylsiloxane (PDMS).

4. The method of any one of claims 1 to 3, wherein the film is optionally selected from the group consisting of semiconductors, metals, insulators, or their combination, such as: graphene / graphite, transition metal dichalcogenides [e.g., molybdenum disulfide (M0S2), tungsten diselenide (WSe2), tungsten disulfide (WS2)], transition metal carbides and nitrides (MXenes), black phosphorus, boron nitride, arsenide, antimonide, telluride, silicene, germanene, phosphorene, borophene, stanene, bismuthene, indium selenide (InSe), gallium selenide (GaSe), tin selenide (SnSe), indium sulfide (InS), gallium sulfide (GaS), tin sulfide (SnS), indium telluride (InTe), gallium telluride (GaTe), tin telluride (SnTe), black arsenic phosphorus (b-AsP), bismuth oxyselenide (Bi2O2Se), oxides (e.g.Ga2C>3, LaAICh, SrTiOs, etc.), and other materials like diamond, SiC, GaN, GaAs scaled down to membranes, and more.

5. The method of any one of claims 1 to 4, wherein the film is a 2D layered material, such as transition metal dichalcogenide, or is a relatively thicker inorganic membrane formed from Bi2O2Se, Ga2Os or other materials.

6. The method of any one of claims 1 to 5, wherein the film is homogenous.

7. The method of any one of claims 1 to 5, wherein the film comprises two or more sublayers or superlattices, or an in-plane mixture of different materials.

8. The method of claim 7, wherein the sublayers of the film are optionally selected from the group consisting of semiconductors, metals, insulators, or their combination, such as: graphene / graphite,, transition metal dichalcogenides [e.g., molybdenum disulfide (M0S2), tungsten diselenide (WSe2), tungsten disulfide (WS2)], transition metal carbides and nitrides (MXenes), black phosphorus, boron nitride, arsenide, antimonide, telluride, silicene, germanene, phosphorene, borophene, stanene, bismuthene, indium selenide (InSe), gallium selenide (GaSe), tin selenide (SnSe), indium sulfide (InS), gallium sulfide (GaS), tin sulfide (SnS), indium telluride (InTe), gallium telluride (GaTe), tin telluride (SnTe), black arsenic phosphorus (b-AsP), bismuth oxyselenide (Bi2O2Se), oxides (e.g. Ga2Os, LaAIOs, SrTiOs, etc.), and other materials like diamond, SiC, GaN, GaAs scaled down to membranes, and more, and their superlattices or stacks.

9. The method of any one of claims 1 to 8, wherein the sacrificial photoresist layer is softened P-PR, and the overlying photoresist layer is P-PR or N-PR.

10. The method of any one of claims 1 to 9, wherein the sacrificial photoresist layer is homogeneous and / or the overlying photoresist layer is homogeneous.

11. The method of any one of claims 1 to 9, wherein the sacrificial photoresist layer comprises two or more sub-layers and / or the overlying photoresist layer comprises two or more sub-layers.

12. The method of any one of claims 9 to 11 , wherein the P-PR comprises a main polymer resin (e.g., phenolic resin) and a photoactive compound (PAC), (e.g., naphtoquinone diazide (NQD)), and the N-PR comprises the main a polymer resin, a photoinitiator, and a cross-linking agent.

13. The method of any one of claims 1 to 12, wherein the removal step comprises use of a developer.

14. The method of claim 13, wherein the developer is an aqueous solution optionally comprising a surfactant.

15. The method of any one of claims 1 to 14, wherein the material is a metal, an oxide, an alloy, or other inorganic material.

16. The method of any one of claims 1 to 15, wherein the material is deposited by physical vapor deposition (PVD) methods including pulsed laser deposition (PLD), molecular- beam epitaxy (MBE), oxide molecular-beam epitaxy (OMBE), RF or DC magnetron sputtering deposition, thermal evaporation, electron beam evaporation, arc vapour deposition, ion plating, reactive PVD and others, and / or chemical vapor deposition (CVD) methods including cold- or hot-wall CVD, atomic layer deposition (ALD), metal organic CVD on (MOCVD), thermal CVD, plasma-enhanced CVD (PECVD), photo-enhanced CVD (photo-CVD), low-pressure CVD (LPCVD), high-pressure CVD (HPCVD), laser- assisted CVD (LCVD), atmospheric pressure CVD and others.

17. The method of any one of claims 1 to 16, wherein the solvent comprises an organic solvent or a mixture of two or more organic solvents.

18. A film disposed on a support and having a patterned material thereon, when produced by the method according to any one of claims 1 to 17.

19. A layered structure comprising a support, a film disposed on the support, a sacrificial photoresist layer disposed on the film, and an overlying photoresist layer disposed on the sacrificial photoresist layer, the sacrificial photoresist layer adapted to be soluble in resist developer (either before or after exposing to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left,20. A method for making the layered structure according to claim 19, the method comprising: providing the support having the film disposed thereon; providing the sacrificial photoresist layer disposed on the film; and providing the overlying photoresist layer disposed on the sacrificial photoresist layer.

21. The method of claim 20, wherein the film is disposed on the support by a thin film growth technique, or thin film transfer technique, or a combination of both.

22. The method of any one of claims 20 to 21 , wherein the sacrificial photoresist layer is softened P-PR.

23. The method of claim 22, further comprising the step of softening the P-PR by ultraviolet light (or EUV, DUV) to provide the softened P-PR before providing the overlying photoresist layer.

24. The method of claim 23, wherein the overlying photoresist layer is P-PR or N-PR.

25. Use of a sacrificial photoresist layer and an overlying photoresist layer in a method of producing a patterned material disposed on a film disposed on a support.

26. Use of a sacrificial photoresist layer in a method of substantially avoiding or avoiding the presence of PR residues on film disposed on a support and at the interface between the patterned material and the film layer disposed on a support, the sacrificial photoresist layer adapted to be soluble in resist developer (either before or after exposing to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left.

27. A method for substantially avoiding or avoiding the presence of PR residues on a film disposed on a support and at the interface between the patterned material and the film layer disposed on a support, the method comprising the steps of: providing a layered structure comprising a sacrificial photoresist layer disposed on the film, and an overlying photoresist layer disposed on the sacrificial photoresist layer, the sacrificial photoresist layer adapted to be soluble in resist developer (either before or after exposing to UV) with minimized residues, and releasable from the underlying film upon exposure to a solvent with minimized residues left, patterning the overlying photoresist layer and the sacrificial photoresist layer to produce masked and un-masked areas of the film layer, depositing a material on at least the un-masked areas of the film; and in the masked areas, exposing the sacrificial photoresist layer to solvent such that the sacrificial photoresist layer releases from the underlying film, thereby providing the film with the patterned material thereon.

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