Patent Publication Number: US-2020285148-A1

Title: Inorganic-Infiltrated Polymer Hybrid Thin Film Resists for Advanced Lithography

Description:
The present application claims priority from U.S. provisional patent application Ser. No. 62/814,633, filed on Mar. 6, 2019, and U.S. provisional patent application Ser. No. 62/853,783, filed on May 29, 2019, both of which are incorporated herein in their entirety. 
    
    
     STATEMENT OF GOVERNMENT RIGHTS 
     The present application was made with government support under contract number DE-SC0012704 awarded by the U.S. Department of Energy. The United States government has certain rights in the invention(s). 
    
    
     FIELD OF THE INVENTION 
     This application relates to the methodologies of preparing and using inorganic-infiltrated organic polymer thin films, where inorganic components are certain metals, metal oxides or metal-based precursors, as organic-inorganic hybrid thin film resist materials to enhance the performance of resists and improve lithography techniques. 
     BACKGROUND 
     The tremendous computational power possessed by today&#39;s modern computer chips is due to millions of transistors with critical dimension as small as 10 nm. Lithography-based patterning has been instrumental in achieving such a high device density. In order to meet the growing requirements of patterning smaller and smaller linewidths at high throughput, continuous advances in the lithography techniques has been essential. For the sub-10 nm nodes and beyond, extreme ultraviolet (EUV) lithography, one of the most recent one of such advancements, with 13.5 nm wavelength is being implemented for high volume manufacturing. Use of such a short wavelength for the lithography is expected to decrease the number of patterning steps in the fabrication process flow as well as decrease the layout complexity by replacing multi-patterning steps with single-step EUV patterning [Chem. Soc. Rev. 2017, 46, 4855]. 
     The resists for EUV lithography pose rigorous requirements such as high optical absorption, high etch resistance, high sensitivity and resolution as well as low line edge roughness (LER). The traditional go-to candidates, such as chemically amplified resists (CARs), fall short in meeting these necessities. For smaller nodes, these traditional carbon-based resist materials typically show poor etch resistance and are thus insufficient for allowing etching-based pattern transfer of high-aspect-ratio structures onto the substrate. Metal containing organic-inorganic resists are being investigated to meet these needs, the reason for which is threefold. The first two are increase in etch resistance due to addition of more robust metal atoms into the polymeric backbone and improvement in line-edge roughness (LER) due to the use of smaller molecules compared to CARs. Additionally, the third advantage of the hybrid approach stems from the perceived mechanism of EUV lithography, where the energy levels within the constituting atoms absorb the incident EUV radiation generating secondary electrons that then cause the changes in the resist&#39;s chemical structure, as against to the inter-atomic chemical bonds directly absorbing the incident radiation in case of earlier lithography wavelengths (e.g. 193 nm). This means that by addition of metals with high EUV absorption coefficient could be utilized for enhancing resist sensitivity and thus, achieving required throughput even with the currently existing low power EUV sources.  FIG. 1  illustrates the atomic absorption cross section of various elements for 13.5 nm wavelength. 
     Many avenues are being investigated for developing EUV resist materials containing metal atoms such as Zr, Hf, Sn, Ti (Chem. Mater. 2015, 27, 5027; Nanoscale 2016, 8, 1338; Appl. Phys. Express 2016, 9, 031601; Proc. SPIE Advances in Patterning Materials and Processes XXXV 2018, 10586, 105860K). The popular approaches that have been implemented to address this challenge are based on metal oxide nanoparticles coated with organic shell of photoactive ligands such as acrylate derivatives [Nanoscale 2016, 8, 1338]; metal containing oxo-cages (J. Micro/Nanolith. MEMS MOEMS, 2017, 16(3), 033510); and metal containing salt complexes (RSC Adv., 2018, 8, 10930-10938). 
     All these approaches depend heavily on optimizing complex chemical synthesis and require establishment of new infrastructure. Moreover, the limited shelf-life of these resist materials also possess restriction on their long-term use. In particular, metal-oxide nanoparticle approach may fall short in achieving required low LER for future nodes, whereas metal containing salt complexes are inherently likely to only provide low metal loading. 
     Therefore, there remains a need for improved methods to prepare resist materials for advanced lithography methods. 
     SUMMARY OF THE INVENTION 
     The present invention provides improved methods to prepare resist materials for advanced lithography methods using existing infrastructure and materials without the need for complex chemical synthesis methodologies. 
     In one embodiment, the present invention provides a method of preparing a metal-infiltrated resist material, said method comprising, consisting essentially of, or consisting of: infiltrating a metal into a resist material to provide the metal-infiltrated resist material; and wherein infiltrating comprises vapor-based infiltration using atomic layer deposition (ALD) tools, or liquid-phase infiltration. 
     In one embodiment, the present invention provides a method of lithography, said method comprising, consisting essentially of, or consisting of: obtaining a metal-infiltrated resist material made by a process according to the aforementioned; and patterning the metal-infiltrated resist material to provide a patterned metal-infiltrated resist material. 
     This application relates to infiltrated PMMA (polymethylmethacrylate) organic methodologies and infiltrating certain metals or metal-based precursors (also referred to herein as metal precursors) into resist materials to enhance the performance of resists and improve lithography techniques. 
    
    
     
       DESCRIPTION OF THE FIGURES 
         FIG. 1  depicts atomic absorption cross sections of various elements for 13.5 nm wavelength radiation (J. Micro/Nanolithography, MEMS, MOEMS 2016, 15, 033506). 
         FIG. 2  depicts a schematic representation of an exemplary vapor-phase infiltration synthesis process. 
         FIG. 3  depicts an atomic force microscopy (AFM) image of an electron beam lithography (EBL) dose test performed on AlO x -PMMA hybrid resist with (a) 0-cycle i.e. PMMA (polymethyl methacrylate) as spin-coated, (b) 4-cycles and (c) 8-cycles of AlO x  infiltration. 
         FIG. 4  depicts evolution of resist characteristics of the hybrid nanocomposite resist with increasing number of infiltration cycles (a) dose response curve for PMMA (0 cycle), 1 cycle, 2 cycle, 3 cycle, 4 cycle, 6 cycle, and 8 cycle, and (b) resist etch rate for differently used etch recipes, Cryo Si, SiO 2 , and O 2 . 
         FIG. 5  depicts (a) scanning electron microscopy (SEM) micrographs, and (b) as developed sub-micron features patterned into 4-cycle infiltrated hybrid resist using EBL. (c), (d), (e), and (f) show 60° tilted view SEM images of Si nanostructures etched using 4-cycle infiltrated resist and etched under cryo-Si recipe at −100° C. under cryo-Si recipe. 
         FIG. 6  depicts results from the EUV lithography experiments at NSLS-II (a) optical microscope image of the x-ray photoemission electron microscopy (XPEEM) beam onto PMMA after exposure to 24.5 mJ/cm 2  dose and development, and (b) analysis of the area spread of the beam on hybrid resists containing different metal oxides infiltrated into PMMA matrix. 
         FIG. 7  depicts (a) schematic representation of liquid phase infiltration process, and (b) cross-sectional transmission electron microscopy (TEM) image depicting uniform Pt infiltration into PVP thin film. 
         FIG. 8  depicts lithography and exposure wavelength, and depicts a plot of process nodes (nm) over years. 
         FIG. 9  depicts high resolution resist challenges. 
         FIG. 10  depicts organic-inorganic hybrid resists. 
         FIG. 11  depicts organic-inorganic hybrid resists for EUV-lithograph (EUVL) 
         FIG. 12  depicts infiltration synthesis (IS). 
         FIG. 13  depicts and explains how electron beam lithography (e-beam lithography or EBL) is useful for studying EUV resist processes 
         FIG. 14  depicts E-beam dose tests for SIS 0 (PMMA), SIS 1, SIS 2, SIS 3, SIS 4, and SIS 8, and a dose response curve for PMMA, and cycles of SIS 1, SIS 2, SIS 3, SIS 4, and SIS 8. 
         FIG. 15  depicts tuning the resist response with TMAH dip showing a schematic representation of ALD AlO x  Deposition on PMMA-AlO x  Hybrid, showing four atomic force microscopy (AFM) images, two images for SIS 3 Cycle and two images for SIS 4 Cycle, showing an image of ALD AlO x  Deposition, and showing a dose response curve for SIS 3 Cycle and for SIS 4 Cycle. 
         FIG. 16  depicts EUV (soft x-ray) lithography at NSLS-II. 
         FIG. 17  depicts a schematic representation of an infiltration synthesis process. 
         FIG. 18  depicts scanning electron micrographs of as developed sub-micron features patterned into 4 cycle infiltrated hybrid resist using EBL. 
         FIG. 19  depicts evolution of resist characteristics of the hybrid nanocomposites resist with increasing number of infiltration cycles (a) dose response curve (b) resist etch rate for differently used recipes (c) 60° tilted SEM Image of Si nanostructures etched using Al 2 O 3 , infiltrated resist under cryo-Si recipe and (d) Results from the EUV lithography experiments at NSLS-II summarized as analysis of the area spread of the beam on hybrid resists continuing different metal oxides infiltrated into PMMA matrix, with inset showing optical microscope image of the beam onto PMMA after exposure and development. 
         FIG. 20  depicts variation of quartz crystal microbalance (QCM) estimated AlO x  mass gain against number of infiltration cycles. 
         FIG. 21  depicts TEM images of the cross sections of resist thin films (a) without any infiltration (0-cycle), (b) after 4-cycles of infiltration, and (c) after 8 cycles of infiltration with increasing dense thin layer of AlO x  forming at the top surface with increasing amount of infiltration. 
         FIG. 22  depicts change in PVP (poly(vinylpyridine)) photoresist film thickness when infiltrated with Pt metal at the following temperatures: 22° C., 42° C., 62° C., and 82° C. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention provides improved methods to prepare resist materials for advanced lithography methods using existing infrastructure without the need for complex chemical synthesis methodologies. 
     As used herein, “metal-infiltrated resist material”, “hybrid resists”, and “metal-infiltrated resist” are used interchangeably to describe the resist material of the present invention. 
     The present method relies upon infiltrating certain metals, including but not limited to Al, Zn, Sn, Ti, Zr, Hf, In, Sb, Co, Ni, Pd, W, Pt, Au, Cu, Ga, Zn, Cr, Fe, Cs, and their oxides into the thin films of a resist material. One metal, one metal oxide, or a doped metal oxide (e.g., a combination of one metal and one metal oxide) may be used in the infiltration; or a combination of two or more metals, a combination of two or more metal oxides, or doped metal oxides (e.g., a combination of two or more metals and metal oxides) may be used in the infiltration for desired results. 
     Examples of suitable metal oxides include AlO x , ZnO x , SnO x , HfO x  TiO x , ZrO x , GaO x , InO x  and other metal oxides. In some embodiments, the metal oxide includes Al 2 O 3 , ZnO, SnO 2 , HfO 2 , ZrO 2 , Nb 2 O 5 , Ga 2 O 3 , In 2 O 3  and TiO 2 . 
     The metals may be in the form of a metal-based precursor. An example of a metal-based precursor includes but not limited to trimethylaluminum (TMA), diethyl zinc (DEZ), titanium isopropoxide, trimethyl gallium, Tetrakis(diethylamido)tin and other ALD precursor. 
     Any resist material commonly known in the art may be used. For example, suitable resist materials include poly(methyl methacrylate) (PMMA) and similar acrylate based resist derivatives, ZEP series, CSAR series, polystyrene derivatives, PVP, poly(2-vinylpyridine), poly(4-vinylpyridine) derivatives, poly(methyl glutarimide) (PMGI), phenol formaldehyde resin (DNQ/Novolac), polyhydoxystyrene-based polymers, polyacrylonitrile and polyimides. 
     Further examples of suitable resist materials include Shipley UV series resists, CSAR series, and ZEP series. 
     The infiltration of the metal or metal oxide can be carried out by vapor phase infiltration using the currently available tools including but not limited to atomic layer deposition chamber and/or by liquid-based infiltration using solutions of metallic salts. The synthesized hybrid resists are suitable for lithographic patterning and subsequent pattern transfer or etching. 
     In some embodiments, the infiltrating includes vapor-based infiltration by using atomic layer deposition (ALD) tools of an ALD system. 
     In some embodiments, the infiltrating includes vapor based infiltration. 
     In some embodiments, sequential infiltration synthesis (SIS) is used. See  FIG. 12  for an exemplary SIS process. 
     In some embodiments, the vapor based infiltration uses 1-12 cycles, 1-8 cycles, 1-4 cycles, 4-8 cycles, or 2-6 cycles. In an exemplary embodiment, one cycle includes a purge and oxidation step, and an infiltration step. See  FIG. 17 . 
     In some embodiments, the vapor based infiltration includes contacting the resist with a metal for a total of 30-800 seconds, 30-500 seconds, 40-100 seconds, or 40-80 seconds. 
     The metal is oxidized. In some embodiments, vapor based infiltration includes contacting the resist with water vapor for a total of 40-100 seconds or 40-80 seconds to oxidize the metal. 
     In some embodiments, the metal comprises a metal ion species selected from the group consisting of PtCl 4   2−  and AuCl 4   2−  or other metal precursors. 
     In one embodiment, the invention provides a method of preparing a metal-infiltrated resist by use of a vapor infiltration process, wherein metal-based precursor trimethylaluminum (TMA) is infiltrated into PMMA film using ALD (atomic layer deposition) tools followed by oxidation of TMA into AlO x  via exposure to H 2 O vapor, generating a hybrid nanocomposite thin film. In the present embodiment vapor phase infiltration is achieved using an ALD system. The tools or components of the ALD system may be used in the present embodiment to perform vapor phase infiltration. For different numbers of infiltration cycles, the patterning characteristics of the synthesized hybrid resist may be determined using EBL.  FIG. 3  shows atomic force microscopy (AFM) image of a dose test performed on AlO x -PMMA hybrid resist with 4-cycles of infiltration. Marked improvement in the resist contrast (y) may be seen as the number of infiltration cycles are increased, with a minor loss of sensitivity ( FIG. 4( a ) ). The evolution of resist etching rate for various etch recipes, as illustrated in  FIG. 4( b ) , showed a prominent enhancement in the etch resistance for chemical etch with increased infiltration compared to physical etch. With the use of 4 cycle infiltrated hybrid resist, lines and elbow patterns may be patterned down to 50 nm linewidth, which can be seen in  FIGS. 5A and 5B . 
     In one aspect, the invention provides a method of preparing a metal-infiltrated resist by use of a liquid phase infiltration method. In this aspect, a resist (described above) is immersed into a metal salt solution of a defined metal salt concentration, for a defined time, and at a defined temperature. See  FIG. 7  for an embodiment of the process of this aspect. 
     In some embodiments, the concentration of the metal salt is 10-100 mM, 10-40 mM, 10-30 mM, 20-30 mM, or 15-25 mM. 
     In some embodiments, the infiltration temperature is 20-80° C., 20-50° C., 20-40° C., 20-30° C., 60-80° C., 40-80° C., 50-80° C., or 18-30° C. 
     In some embodiments, the infiltration temperature is 20-25° C., 40-45° C., 60-65° C., or 80-85° C. 
     The resist is soaked in the metal salt solution for 1-1000, 1-100, 1-500, 250-750, 400-600, 40-100, 500-1000, 750-1,000, or 50-80 seconds. This defines the soak time. 
     In some embodiments, the soak time is 50-80 seconds. 
     In some embodiments, resist material comprises PVP, the salt solution includes Na 2 PtCl 4  at a concentration of 15-25 mM; the infiltration temperature is 18-30° C.; and the soak time is 50-80 seconds. 
     In some embodiments, a liquid phase polymer metal hybridization method is used, in which, the photoresist thin films spun on suitable substrates may be immersed into a metal salt solution. The reactive metal ion species diffuse into the polymer and react with functional groups present within the polymer. For instance, PVP, a pyridine ring containing polymer, when protonated may form pyridinium ion which complexes with metal ion species including but not limited to PtCl 4   2− , AuCl 4   2− . The process is schematically depicted in  FIG. 7( a ) , while a cross section TEM image of Pt hybridized PVP is shown in  FIG. 7( b ) . The amount of infiltration can be controlled via controlling the metal salt concentration, infiltration time and infiltration temperature. After infiltration, the polymer films may be rinsed in solvents suitable for removing the loosely bound salt that may be remaining on the surface of the films and can subsequently be used for lithography purposes. 
     Using the methods described above, a metal is infiltrated into the starting resist material creating an infiltrated metal resist. There may be a deposition of metal or metal oxide on the surface of the starting resist material. The metal-infiltrated resist may be characterized by the mass gain as a result of the methods disclosed herein. See  FIG. 20  for an embodiment of the method disclosed herein, wherein mass gain is determined. 
     Using the methods described above, a metal is infiltrated into the starting resist material creating a metal-infiltrated resist that may have a metal layer having a thickness. In some embodiments, the thickness is greater than about 1 nm, greater than about 2 nm, greater than about 3 nm, greater than about 4 nm, or greater than about 5 nm. In some embodiments, the metal-infiltrated resist material comprises a thickness of between about 5 nm and 50 nm, 5 nm and 40 nm, 10 nm and 50 nm, 10 nm and 40 nm, 20 nm and 40 nm, 1 nm and 20 nm, 10 nm and 20 nm, or 1 nm and 10 nm. The thickness may also be described as a change in thickness (A thickness), this is the difference in thickness from before the infiltration process to after the infiltration process. See  FIG. 22  for exemplary metal-infiltrated resist material and process, and the measured change in thickness. 
     In another aspect, the invention provides a lithography method, including patterning and/or etching of the substrate with metal-infiltrated resist material used as a etch mask described above. 
     The lithography performance of the metal-infiltrated resist materials disclosed herein may provide several benefits over the resist materials of the prior art. Examples of benefits include etch resistance, LER improvement, and higher sensitivity. 
     Etch resistance—the presence of inorganic entities in the organic backbone may provide higher stability to the resist, thus protecting them from plasma damage and increasing etch resistance during pattern transfer. 
     LER improvement—as compared to (chemical amplified resist) CARs, these hybrid resist could have smaller molecules, thus leading to lower LER after the development. 
     Higher sensitivity—Hybrid resist containing certain metal atoms can absorb the incident EUV radiation more efficiently. This may assist in faster pattern exposure and thus, higher lithography throughput. 
     In some embodiments, EUV resist materials may contain metal atoms such as Zr, Hf, Sn, or Ti. Vapor-phase infiltration of metals and/or metal oxides is an effective way to enhance the etch resistance of these resists, using ALD tools. 
     The resolution of an optical lithography system may depend on the wavelength used for patterning. The radiation source may have a wavelength of less than 500 nm, less than 400 nm, less than 300, less than 200 nm, less than 100 nm, less than 50 nm, or less than 20 nm. 
     Accordingly, industrial lithography instruments may exploit visible g-line (436 nm), UV i-line (365 nm), deep UV 248 nm and 193 nm to achieve a desired pattern linewidth. For sub-10 nm nodes and beyond, EUV with 13.5 nm wavelength may be implemented for high volume manufacturing. Use of such a short wavelength for lithography may decrease the number of patterning steps in the fabrication process flow and the layout complexity by replacing multi-patterning steps with single-step EUV patterning. 
     Exemplary lithographic methods include EBL and EUV lithography. 
     In some embodiments, interference lithography may be used. 
     In some embodiments, spin-coated thin films of polymeric resist on Si substrates is infiltrated with different concentrations of inorganic species. The higher atomic absorption of suitable inorganic additive atoms for EUV radiation is expected to improve the sensitivity of the original resist and, thus, increase the throughput of lithographic patterning step. 
     The lithography performance of the metal-infiltrated resist material disclosed herein can be characterized as follows. 
     Resist sensitivity &amp; contrast extraction using exposure dose tests by varying the exposure time at constant exposure intensity followed by the development of the resist. The thickness of the remaining resist in these regions is measured with stylus profilometer or AFM measurement and plotted against the exposure energy to estimate sensitivity and contrast of each resist composition. The sensitivity of PMMA at EUV exposures is ˜25 mJ/cm 2 . [Fallica et. al. J VST B, 2017, 35, 061603] 
     Resist resolution and LER characterization: Nanoscale patterns are exposed on the resist-coated sample. 
     After development of the resist patterns, SEM is used to determine the resolution and LER of the developed patterns. 
     In some embodiments, the exposed patterns are subject to etching. Etching methodologies commonly known in the art may be applied to the patterned hybrid resists described herein. 
     In some embodiments, exposed patterns can also be subjected to reactive ion etching to demonstrate high-aspect ratio patterning capability. 
     In some embodiments, plasma dry etching is used. 
     In some embodiments, the invention provides a method of patterning and etching the hybrid resist material described herein. In some embodiments, the resulting nanostructures have a linewidth of less than about 100 nm, less than about 50 nm, less than about 40, less than about 35, less than about 25 nm, less than about 10 nm, or less than about 5 nm. In some embodiments, the linewidths are between about 5 nm and 50 nm, 10 nm and 50 nm, or between 15 nm and 35 nm. 
     In some embodiments, the nanostructures have an aspect ratio of greater than about 5, greater than about 10, greater than about 15, or greater than about 20. In some embodiments, the aspect ratio is between about 5 and 50, 10 and 50, 10 and 30, or 15 and 25. 
     In some embodiments, the metal infiltrated resists of the present invention have an etch selectivity of greater than about 10, 15, or 20. In some embodiments, the etch selectivity is between about 10 and 40, 10 and 20, 15 and 40, 15 and 20, or 30 and 40. In some embodiments, the maximum etch selectivity may be 300, 350, 400, 450, 500, or more. In some embodiments, the maximum etch selectivity may be about 300 or more for the present metal infiltrated resists having AlO x  infiltrated into PMMA. 
     While PMMA has been popular e-beam lithography resist, a major backbone component of a number of commercial deep UV photoresists (such as UV6 by Shipley) are based on acrylate derivative and are thus quite similar in their mechanism to PMMA. Thus, the process according to the present invention can be with these resists to infuse inorganics into them. AlO x  is a popular choice of hard mask material, particularly in fluorine-based Si etch recipes, due to the formation of AlF 3 , a robust ceramic with very high melting point. Thus, infiltration of AlO x  into UV6 that already exist in the semiconductor production flow, may provide benefits. Moreover, infiltration of SnO x  may provide critical advantage due to the high absorption cross section of Sn for EUV wavelength (13.5 nm), thus resulting in improved sensitivity of the resist and lead to high-throughput lithography patterning. 
     In some embodiments, AlO x  may be infiltrated into UV6 and the resulting metal-infiltrated resist material is further subject to lithography. 
     In some embodiments, SnO x  may be infiltrated into UV6 and the resulting metal-infiltrated resist material is further subject to lithography. 
     Throughout this specification, quantities are defined by ranges having a lower boundary and upper boundary, and by lower or upper boundaries. Each lower boundary can be combined with each upper boundary to define a range. Two lower boundary values can be combined to define a range, and two upper boundary values can be combined to define a range. The lower and upper boundaries should each be taken as a separate element. 
     In the present disclosure, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the Figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein. 
     EXAMPLES 
     The present invention is illustrated in further details by the following non-limiting examples. 
     Example 1, Vapor Phase Infiltration Method of Metals into a Resist Material. AlO x  is Infiltrated into PMMA 
     Commercially available 2 weight % PMMA (Molecular Weight 950000 gm/mol—MicroChem) in anisole was spin coated on cleaned silicon substrates at 7500 rpm for 60 sec, followed by 3 min baking at 180° C. hotplate to form ˜60 nm film as measured by ellipsometry. 
     The substrates with as spun PMMA film were then infiltrated at 85° C. with different AlO x  amount by varying the number of infiltration cycles from 1-12 using a commercial ALD system (Cambridge Nanotech Savannah S100). Each infiltration cycle consisted of TMA exposure for total 60 sec, during which TMA precursor was pulsed for 14 msec every 10 sec, followed by purging of the ALD chamber with 100 sccm N 2  for 2 min. Consequently, the substrates were exposed to water vapor for total 60 sec, while the 40 msec pulses were employed every 10 sec, followed by 2 min purge by 100 sccm N 2 , completing the infiltration cycle. 
     The amount of alumina inclusion into the PMMA matrix was estimated using QCM measurements. As shown in the figure below, resulting areal mass gain for different number of infiltration cycles increases continuously. With up to 12 infiltration cycles, the amount of mass gain due to alumina inclusion was estimated to be 5.36 μg/cm 2 . The depicted examples of e-beam patterning were conducted using 4-cycle infiltrated samples (3.89 μg/cm 2  of AlO x ), which was then utilized for producing etched Si nanostructures using cryogenic Si etch recipe. 
     QCM estimated AlO x  mass gain against number of infiltration cycles was tested on metal infiltrated resist material prepared by vapor phase infiltration method disclosed herein. See  FIG. 20 . 
     A vapor infiltration process is depicted in  FIG. 2 ; wherein ALD precursor TMA is infiltrated into PMMA film followed by oxidation of TMA into AlO x  via exposure to H 2 O vapor, generating a hybrid nanocomposite thin film. For different numbers of infiltration cycles, the patterning characteristics of the synthesized hybrid resist may be investigated using EBL.  FIG. 3  shows AFM image of a dose test performed on AlO x — PMMA hybrid resist with 4-cycles of infiltration. Marked improvement in the resist contrast (y) may be seen as the number of infiltration cycles are increased, with a minor loss of sensitivity ( FIG. 4( a ) ). The evolution of resist etching rate for various etch recipes, as illustrated in  FIG. 4( b ) , showed a prominent enhancement in the etch resistance for chemical etch with increased infiltration compared to physical etch. With the use of 4 cycle infiltrated hybrid resist, lines and elbow patterns may be patterned down to 50 nm linewidth, which can be seen in  FIG. 5( a,b ) . 
     Moreover, after fabricating nanoscale patterns with EBL, samples were also subjected to cryo-Si etching process. On accord of improved etch resistance of the infiltrated hybrid resists, Si nanostructures with linewidth down to ˜30 nm and high aspect ratio of ˜17 were achieved.  FIGS. 5 ( c,d )  depict the 500 nm linewidth structures etched down to ˜700 nm with the starting resist thickness of ˜60 nm while  FIGS. 5 ( e,f )  portray highest resolution (˜30 nm) structures we were able to etch with a depth of ˜530 nm. These results demonstrate the etch selectivity of ˜70 (for 4-cycle infiltrated resist) or ˜310 (for 8-cycle infiltrated resist) compared to the PMMA or ZEP etch selectivity is marked 5 to 14-fold increment. This selectivity surpasses even the resist of choice for etch based processing such as ZEP and HSQ. Subsequent to the EBL study, the utility of these resist has also been investigated for EUV lithography using soft x-rays beamlines (XPEEM) at the NSLS-II light source, the results of which can be seen in  FIG. 6 . The variation in the beam spread for different metal oxide infiltration into PMMA matrix shows that the properties of the resist can be effectively modified with the present method. 
     An EBL dose test was performed on AlO x -PMMA hybrid resist with 0-cycle i.e. PMMA as spin-coated, 4-cycles, and 8-cycles of AlO x  infiltration. See  FIG. 3 . 
     Evolution of resist characteristics of the hybrid nanocomposite resist with increasing number of infiltration cycles dose response curve, and resist etch rate for commonly used etch recipes were tested. See  FIG. 4 . 
     Scanning electron micrographs of as developed sub-micron features patterned into 4-cycle infiltrated hybrid resist using EBL. See  FIG. 5 . 
     SEM images of Si nanostructures etched (0° tilted view) using 4-cycle infiltrated resist and under cryo-Si recipe−100° C. were taken. See  FIG. 5 . 
     EUV lithography experiments were conducted at NSLS-II and optical microscope image of the XPEEM beam onto PMMA after exposure to 24.5 mJ/cm 2  dose and development were taken. See  FIG. 6A . Analysis of the area spread of the beam on hybrid resists containing different metal oxides infiltrated into PMMA matrix were conducted. See  FIG. 6B . 
     Example 2, Liquid Phase Infiltration Method of Metals into a Resist Material. Pt is Infiltrated into PVP 
     A liquid phase polymer metal hybridization in which the photoresist thin films spun on suitable substrates is immersed into a metal salt solution. The reactive metal ion species diffuses into the polymer and react with functional groups present within the polymer. For instance, PVP, a pyridine ring containing polymer, when protonated may form pyridinium ion which complexes with metal ion species including but not limited to PtCl 4   2− , AuCl 4   2− . The process is schematically depicted in  FIG. 7( a ) , while a cross section TEM image of Pt hybridized PVP is shown in  FIG. 7( b ) . The amount of infiltration can be controlled via controlling the metal salt concentration, infiltration time and infiltration temperature. After infiltration, the polymer films may be rinsed in solvents suitable for removing the loosely bound salt that may be remaining on the surface of the films and can subsequently be used for lithography purposes. 
     For example, the PVP photoresist thin films spun on suitable substrates are immersed into a metal salt solution (˜20 mM) at a suitable, predetermined temperature (22° C.) for a predetermined soak time (60 sec). The main experimental parameters that are used to control the quantity of infiltration into the polymer film include metal salt solution concentration (1 mM to 100 mM), infiltration temperature (20° C. to 80° C.), infiltration soak time (0-1000 sec). After infiltration, the polymer films are rinsed in suitable solvents to remove the loosely bound salt remaining on the surface of the films and can be subsequently used for lithography purpose. Further ellipsometry or electron microscopy techniques are utilized to estimate the quantity of infiltration into the polymer film. 
     Ex-situ ellipsometry measurements, for instance can give an estimate of the infiltration quantity by changing the infiltration temperature. Increase in film thickness (A) as a result of hybridization of PVP photoresist with Na 2 PtCl 4  complex salt solution is recorded as a function of infiltration temperature and time ( FIG. 3 ). These hybrid films can be further patterned with electron beam and photolithography. 
     PVP photoresists were subject to the liquid phase infiltration described herein at the following temperatures 22° C., 42° C., 62° C., and 82° C., and the change in thickness was measured. See  FIG. 22 . 
     Example 3, Characterization of Metal-Infiltrated Resist Material by Lithography and Etching 
     Lithograph-based patterning may contribute to achieving higher computing performance among integrated circuits by increasing the device areal density. However, there may be technological challenges, with cost-effective patterning at sub-30 nm dimensions being one. The patterning linewidth and throughput may depend on the resist materials. The semiconductor process may be dependent on CARs to obtain certain nanopatterns. However, when working with smaller nodes, these types of carbon-based resist materials may show poor etch resistance and therefore may be sufficiently allow for etching-based pattern transfer of high-aspect-ratio structures onto the substrate. 
     Study parameters of a EUV resist, viz.: Sensitivity (S), contrast (y), resolution (R) and line-edge roughness (LER), in order to establish the performance of inorganic infiltrated photoresists for EUV patterning. Spin-coated thin films of polymeric resist on Si substrates are infiltrated with different concentrations of inorganic species. The higher atomic absorption of suitable inorganic additive atoms for EUV radiation is expected to improve the sensitivity of the original resist and, thus, increase the throughput of lithographic patterning step. The decrease in the required photon dose for patterning is also expected to decrease the photon shot noise and blurring effects of photoelectrons, leading to improved resolution and LER characteristics of the generated nano-patterns. 
     The resolution of an optical lithography system may depend on the wavelength used for patterning. Accordingly, industrial lithography instruments may exploit visible g line (436 nm), UV i-line (365 nm), deep UV 248 nm and 193 nm to achieve a desired pattern linewidth. For sub-10 nm nodes and beyond, EUV with 13.5 nm wavelength may be implemented for high volume manufacturing. Use of such a short wavelength for lithography may decrease the number of patterning steps in the fabrication process flow and the layout complexity by replacing multi-patterning steps with single-step EUV patterning. 
     The resists for EUV lithography may have requirements such as high optical absorption, high etch resistance, high sensitivity and resolution as well as low line edge roughness (LER). At sub-20 nm patterning dimensions, resists in the existing schemes may exhibit low sensitivity as well as high LER, effectively putting constraints on an attainable pattern resolution, while their poor etch resistance may be less than adequate for transferring high aspect ratio structures in the substrate. In order to overcome these challenges, metal-containing organic-inorganic hybrid resists are of interest. 
     Resist sensitivity and contrast extraction are tested using exposure dose tests by varying the exposure time at constant exposure intensity followed by the development of the resist. The thickness of the remaining resist in these regions are measured with stylus profilometer or AFM measurement and plotted against the exposure energy to estimate sensitivity and contrast of each resist composition. The sensitivity of pure organic matrixes under EUV exposures is expected to 10-25 mJ/cm 2 . 
     Resist resolution and LER characterization is tested. For these tests, nanoscale patterns are exposed on the resist-coated sample Alternatively, interference lithography (IL) technique is implemented using either of the endstations. After development of the resist patterns, SEM is used to determine the resolution and LER of the developed patterns. Exposed patterns are subjected to reactive ion etching to demonstrate high-aspect ratio patterning capability. 
     Example 4, Electron Beam Lithography 
     Electron Beam Lithography: 
     E-beam exposure on the prepared samples was carried out using JEOL JBX-6300FS e-beam lithography system (100 kV). For the exposure matrix patterning typically 500 pA current was used to expose 5 μm square area with electron dose ranging from 50 μC/cm2 to 7000 μC/cm2 using a shot spacing of 8 nm. For exposing sub-micro sale features consisting of lines and elbow patterns 1 nA beam current and 4 nm shot spacing was used (exposure dose range differed for various formulations). After the exposure, samples were developed in methyl iso-butyl ketone (MIBK) solution in isopropyl alcohol (IPA) in the ratio of MIBK:IPA 1:3 for 45 sec followed by 15 sec rinse in IPA. 
     Example 5, Plasma Dry Etching 
     All ICP-RIE processing was conducted in Oxford Plasmalab 100. The plasma processing conditions are outlined as followed: 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                   
                 RF 
                 ICP 
                 Gas  
               
               
                   
                 Temper- 
                 Pressure 
                 Power 
                 Power 
                 flow 
               
               
                 Process 
                 ature 
                 (mTorr) 
                 (W) 
                 (W) 
                 rate 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 O 2  Etch 
                  20° C. 
                 30 
                 200 
                 0 
                 O 2  50 
               
               
                   
                   
                   
                   
                   
                 sccm 
               
               
                 SiO 2  Etch 
                  25° C. 
                 15 
                 40 
                 700 
                 O 2  1.5 
               
               
                   
                   
                   
                   
                   
                 sccm 
               
               
                   
                   
                   
                   
                   
                 CHF 3   
               
               
                   
                   
                   
                   
                   
                 50 sccm 
               
               
                 Cryo Si Etch (etch 
                 −100° C. 
                 15 
                 15 
                 800 
                 O 2  12 
               
               
                 rate) 
                   
                   
                   
                   
                 sccm 
               
               
                   
                   
                   
                   
                   
                 SF6 40 
               
               
                   
                   
                   
                   
                   
                 sccm 
               
               
                 Cryo Si Etch 
                 −100° C. 
                 15 
                 15 
                 800 
                 O 2  16 
               
               
                 (nanopatterning) 
                   
                   
                   
                   
                 sccm 
               
               
                   
                   
                   
                   
                   
                 SF 6  40 
               
               
                   
                   
                   
                   
                   
                 sccm 
               
               
                   
               
            
           
         
       
     
     For the etch rate measurements, the resist film thickness was measured after different etch times with the use of Woollam Spectroscopic Ellipsometer and Cauchy model fitting. Whereas, prior to plasma etching of nanopatterned structure a descum step consisting of 5 sec dip in commercially available ma-D 525 (micro resist technology GmbH) for 5 sec to remove inorganic residue followed by 10 sec 02 plasma ashing (20 W, 100 mTorr) under March Plasma. 
     Example 6, Comparative Benchmark Performance of Resists 
     The performance of several various e-beam lithography resist processes of the prior art, as compared to an exemplary e-beam lithography process of the present invention. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Comparison of various e-beam lithography resist processes and their properties. 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                   
                   
                   
                   
                 Etched 
                   
                 Dose 
                   
                 Resist 
                 Si Etch 
                   
               
               
                   
                   
                 Post Litho 
                 LW 
                 Depth 
                 Aspect 
                 (μC/cm 2 ) 
                 Etch 
                 Etch Rate 
                 Rate 
                 Selectivity 
               
               
                 Resist 
                 Litho 
                 Treatment 
                 (nm)  
                 (nm) 
                 Ratio 
                 [*J/cm 2 ] 
                 Recipe 
                 (nm/min) 
                 (nm/min) 
                 with Si 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                 PMMA  [1,2]   
                 EBL 
                   
                 20 
                 10 
                 0.5 
                 ~500 
                 HBr 
                 300 
                 100 
                 3 
               
               
                 PMMA  [1]   
                 EBL 
                 SIS 
                 18 
                 130 
                 7.22 
                   
                 HBr 
                 &lt;4 
                 100 
                 &gt;25 
               
               
                 PMMA  [2]   
                 EBL 
                 SIS 
                 ~150  
                 1500 
                 ~10 
                   
                 HBr 
                 ~8 
                 100 
                 ~12.5 
               
               
                 ZEP520A  [2]   
                 EBL 
                   
                   
                   
                   
                   
                 HBr 
                 100 
                 100 
                 1 
               
               
                 ZEP520A  [2]   
                 EBL 
                 SIS 
                   
                   
                   
                   
                 HBr 
                 20 
                 100 
                 5 
               
               
                 Al-Si 
                 Soft 
                 100° C. for  
                 400 
                 3300 
                 8.5-17.5 
                 20* 
                 SF 6 -C 4 F 8 -Ar 
                 2.67 
                 170 
                 &gt;60 
               
               
                 complex  [3]   
                 Xray 
                 60 s 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                   
                 (Neg) 
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 Al-Si 
                 EBL 
                   
                 20 
                 400 
                 20 
                 200-250 
                 SF 6 -C 4 F 8 -Ar 
                 2.67 
                 170 
                 &gt;100 
               
               
                 complex  [4]   
                 3 kV 
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                   
                 (Neg) 
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 Al-Si 
                 EBL 
                   
                 &lt;100, 
                 3000 
                 &gt;30 
                 800 
                 SF 6 -C 4 F 8 -Ar 
                 ~1.7 
                 170 
                 100 
               
               
                 complex  [5]   
                 (Dual) 
                   
                 min 20 
                   
                   
                   
                   
                   
                   
                   
               
               
                   
                 30 kV 
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 HSQ  [5]   
                 EBL 
                   
                 10 
                   
                   
                 5000 
                 SF 6 -C 4 F 8 -Ar 
                   
                 170 
                 6 
               
               
                   
                 neg 
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 Exemplary 
                 EBL 
                   
                 31.6  
                 533 
                 16.87 
                 ~2000 
                 SF 6 -O 2 -Cryo 
                 40.67 
                 ~2895 
                 ~71.2 
               
               
                 example of  
                 100 kV 
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 the present 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 invention 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 4-cycle 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 hybrid 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                   
               
               
                 Table 2 References: 
               
               
                   [1]  Y. C. Tseng, A. U. Mane, J. W. Elam, S. B. Darling,  Adv. Mater.  2012, 24, 2608. 
               
               
                   [2]  Y.-C. Tseng, Q. Peng, L. E. Ocola, D. A. Czaplewski, J. W. Elam, S. B. Darling,  J. Mater. Chem.  2011, 21, 11722. 
               
               
                   [3]  G. Grenci, G. Della Giustina, A. Pozzato, E. Zanchetta, M. Tormen, G. Brusatin,  Microelectron. Eng.  2012, 98, 134. 
               
               
                   [4]  G. Grenci, E. Zanchetta, A. Pozzato, G. Della Giustina, G. Brusatin, M. Tormen,  Appl. Mater.   Today  2015, 1, 13. 
               
               
                   [5]  E. Zanchetta, G. Della Giustina, G. Grenci, A. Pozzato, M. Tormen, G. Brusatin,  Adv. Mater.  2013, 25, 6261.