Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/004—Photosensitive materials
  • G03F7/0042—Photosensitive materials with inorganic or organometallic light-sensitive compounds not otherwise provided for, e.g. inorganic resists
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/20—Exposure; Apparatus therefor
  • G03F7/2002—Exposure; Apparatus therefor with visible light or UV light, through an original having an opaque pattern on a transparent support, e.g. film printing, projection printing; by reflection of visible or UV light from an original such as a printed image
  • G03F7/2004—Exposure; Apparatus therefor with visible light or UV light, through an original having an opaque pattern on a transparent support, e.g. film printing, projection printing; by reflection of visible or UV light from an original such as a printed image characterised by the use of a particular light source, e.g. fluorescent lamps or deep UV light
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/26—Processing photosensitive materials; Apparatus therefor
  • G03F7/38—Treatment before imagewise removal, e.g. prebaking
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P76/00—Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography
  • H10P76/20—Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography of masks comprising organic materials
  • H10P76/204—Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography of masks comprising organic materials of organic photoresist masks
  • H10P76/2041—Photolithographic processes

Definitions

• the present invention relates to the use of specific chemical compounds as patterning agents in the photolithography and/or electron beam patterning . It can be used in the field of semiconductor chip production, particularly but not limited to EUV wavelengths , and direct patterning of functional materials for applications such as masks in semiconductor industry, sensors , photonics or catalysis .
• Photolithography has been the bedrock of fabricating devices in micro- and nanometer regime in the semiconductor industry . It uses a resist, usually a photosensitive polymeric material , for imaging and pattern transfer to a substrate either via the process of plasma etching or by lift-off after metal (oxide) deposition .
• a resist usually a photosensitive polymeric material
• EUV technology 13 . 5 nm wavelength
• ArF immersion lithography has emerged as the strong alternative to ArF immersion lithography for high volume manufacturing .
• novel resist materials that possess high sensitivity at this wavelength, capable of high resolution, exhibit low line edge roughness (LER) , and at the same time preserving the pattern fidelity and uniformity .
• Chemically amplified resists (CAR) which are primarily organic, have served very well in 248 nm and 193 nm lithography but are very transparent in EUV wavelength .
• the graph in Figure 13 provides theoretically calculated EUV absorption cross-section of various elements .
• the data here provide guidelines for the choice of elements in EUV resists that would increase the absorption of radiation .
• elements with higher EUV absorption cross-section are preferred .
• a patterning agent such as a photo-resist
• a patterning agent such as a photo-resist
• This obj ective is achieved according to the present invention by the use of a metal and/or metalloid-comprising ketoacidoximate and/or a metal-compound-comprising ketoacidoximate as a patterning agent in photolithography and electron beam lithography with applications in the field of semiconductor chip production, and direct patterning of functional materials for mask production, sensors , photonics or catalysis .
• metal and/or metalloid-comprising ketoacidoximate and/or a metal-compound-comprising ketoacidoximate show exactly the desired properties in terms of high EUV absorbance or electron beam sensitivity that results in the desired sensitivity .
• EUV lithography uses a shorter wavelength ( 13 . 5 nm) radiation that necessitates development of novel photoresists sensitive to this wavelength . Since at this wavelength, conventional carbon-based resists are fairly transparent, novel resists that contain heavier elements that highly absorb EUV radiation are needed . It is logical to incorporate in resists metals such as tin with high absorption cross-section at EUV wavelength ( Figure 1 ) to improve their sensitivity . However, the exposure of the resist happens via the secondary electrons generated in the resist volume during the EUV exposure . How effective these electrons are in breaking bonds in the resist also matters .
• the efficacy of secondary electrons has been considered in exposure of resist using empirical means .
• nickel and zinc have similar EUV absorption cross-sections .
• one presently preferred resist containing zinc needs a much lower dose for exposure than the nickel resist with the same ligand environment, suggesting that the interaction between secondary electrons play a maj or role in the irradiation process .
• a divalent metal or metalloid or metal-compound comprising ketoacidoximate can have one of the following structural forms :
• Ri and R 2 stand for hydrogen (H) , organic groups , such as aliphatic C 3 to Ci 0 , aromatic, cyclic, polymerizable, such as acrylate, methacrylate , vinyl , etc . , or a combination of these; and
• M stands for a central metal or metalloid atom, which can be monovalent, divalent, trivalent, tetravalent, pentavalent or higher, that is attached to the ketoacidoximate group in monodentate, bidentate, or tridentate fashion, and/or for a central metal atom being attached to other groups such as oxide, hydroxide , etc .
• M stands for a central metal atom being attached to a further group R 3 which is a carboxylate such as acetate, etc . , a glycinate, a xanthate, an alkyl , an aryl , or the like .
• the metal atom selected from a group comprising zinc, indium, aluminium, nickel , magnesium, and tin .
• Figure 1 Dose-to-gel curves of zinc ( I I ) methoxyimino propionate resist exposed to (a) EUV and (b) electron beam; ( c) Sensitivity values of the resist obtained with various developers ; Figure 2 EUV lithography of (a) half pitch 22 nm (325 mJ/cm 2 ), (b) half-pitch 18 nm (297 mJ/cm 2 ), and (c) half pitch 16 nm (290 mJ/cm 2 ) lines using zinc (II) methoxyimino propionate resist;
• Figure 5 EUV lithography of (a) half pitch 22 nm (222 mJ/cm 2 ), (b) half-pitch 18 nm (223 mJ/cm 2 ), and (c) half pitch 16 nm (199 mJ/cm 2 ) lines using indium(III) hydroxyimino propionate resist;
• Figure 7 EUV lithography of (a) half pitch 22 nm (193 mJ/cm 2 ), (b) half-pitch 18 nm (194 mJ/cm 2 ) , and (c) half pitch 16 nm (173 mJ/cm 2 ) lines using indium(III) methoxyimino propionate resist;
• Figure 9 EUV lithography of (a) half pitch 50 nm (64 mJ/cm 2 ), and (b) half-pitch 35 nm (51 mJ/cm 2 ) using aluminium ( III ) methoxyimino propionate resist;
• Figure 10 Dose-to-gel curves of nickel (II) methoxyimino propionate resist exposed to (a) EUV and (b) electron beam; (c) Sensitivity values of the resist obtained with various developers;
• the first step involves condensation of an a-keto acid with an amine to give a-oximino acid .
• a-oximino acid is then reacted with a metal/metalloid salt (e . g . , nitrate or chloride) in the presence of a suitable base to given metal/metalloid ketoacidoximate as shown below .
• a metal/metalloid salt e . g . , nitrate or chloride
• the reaction can be carried out in either organic or an aqueous medium .
• Synthesized metal/metalloid ketoacidoximates are found to be sensitive to energetic electrons ( 0 . 5 to 300 kV) , extreme ultraviolet (EUV) radiation ( 92 eV, 13 . 5 nm) and other types of energetic radiation below 250 nm wavelength .
• energetic electrons 0 . 5 to 300 kV
• EUV extreme ultraviolet
• Such sensitivity to electrons and EUV radiation have made them patternable and henceforth they will be called “metal ( loid) -containing patterning agents” or simply “patterning agents” .
• the organic groups attached to amine (Ri) and a-keto acid (R 2 ) can be individually and independently modified .
• These groups can be hydrogen (H) , aliphatic (Ci-Cio) , aromatic, cyclic, polymerizable (acrylate, methacrylate, vinyl , etc . ) , or a combination of these .
• central metal atom that is attached to the ketoacidoximate group
• the central atom attached to other groups as well such as oxide, hydroxide, or any group R 3 such as carboxylate (acetate , etc . ) , glycinate, xanthate, alkyl , aryl , etc .
• the central metal atom could be monovalent, divalent and above .
• Adducts with Lewis bases bonded to central metal atoms are also possible.
• the present invention also provides for a process for patterning a semiconductor surface by coating the surface with the patterning agent and the irradiating of the coated surface with a predefined photon irradiation pattern or electron beam pattern.
• appropriate amounts of patterning agents here photoresists, were dissolved in a solvent, for example 2 -methoxyethanol, to give concentrations between 0.0125 gm/ml to 0.1 gm/ml.
• concentrations in the range of 0.0125 gm/ml to 0.025 gm/ml are found to be suitable.
• These solved resists were spin-coated on pre-cleaned semiconductor substrates, for example silicon substrates, at an appropriate spin-speed, for example a spinspeed of 1800 rpm. They were then exposed to photon radiation, for example EUV radiation, through a mask at a photon source or to electrons, for example 100 kV electrons, inside an electron beam writer.
• the photon radiation can be generated for example in a synchrotron, for example at the Swiss Light Source (SLS) in Villigen PSI, Switzerland (visit for more details on the SLS at www.psi.ch) .
• resists For studying the sensitivity of resists to plot dose-to-gel curves, they were exposed at various doses using EUV or electrons. These resists were developed with various organic solvents such as methanol, ethanol, iso-propanol, 2- methoxyethanol, l-methoxy-2-propanol, 1-butoxyethanol, 3- methoxy-l-butanol, 2-methoxyethyl acetate, and l-methoxy-2- propyl acetate. They were rinsed using the same solvent in which they were developed. For dose-to-gel curves, 10 seconds of development, immediately followed by 5 second rinse, and then blow-drying using nitrogen. The resists showed a negative tone behavior after exposure.
• organic solvents such as methanol, ethanol, iso-propanol, 2- methoxyethanol, l-methoxy-2-propanol, 1-butoxyethanol, 3- methoxy-l-butanol, 2-methoxyethyl acetate, and l
• Figure 1 shows dose-to-gel curves of zinc (II) methoxyimino propionate resists exposed to (a) EUV and (b) electron beam.
• Figure 1 (c) shows the sensitivity values of the resist obtained with various developers .
• Figure 2 shows EUV lithography of (a) half pitch 22 nm (325 mJ/cm 2 ) , (b) half-pitch 18 nm (297 mJ/cm 2 ) , and (c) half pitch 16 nm (290 mJ/cm 2 ) lines using zinc (II) methoxyimino propionate resist .
• Figure 3 shows an electron beam lithography of 5 nm wide lines patterned using zinc (II) methoxyimino propionate resist.
• Figure 4 now shows the dose-to-gel curves of indium (III) hydroxyimino propionate resist exposed to (a) EUV and (b) electron beam.
• Figure 4 (c) shows the sensitivity values of the resist obtained with various developers.
• Figure 5 shows the EUV lithography of (a) half pitch 22 nm (222 mJ/cm 2 ) , (b) halfpitch 18 nm (223 mJ/cm 2 ) , and (c) half pitch 16 nm (199 mJ/cm 2 ) lines using indium (III) hydroxyimino propionate resist.
• Features here are slightly smaller than the designed half pitch due to underdosing.
• Figure 6 shows the dose-to-gel curves of indium (III) methoxyimino propionate resist exposed to (a) EUV and (b) electron beam.
• Figure 6(c) shows the sensitivity values of the resist obtained with various developers. indicates data from poor development characteristics. 'N/A' indicates that data could not be acquired due to excessive scum on the surface .
• Figure 7 shows the EUV lithography of (a) half pitch 22 nm ( 193 mJ/cm 2 ) , (b) half-pitch 18 nm ( 194 mJ/cm 2 ) , and ( c) half pitch 16 nm ( 173 mJ/cm 2 ) lines using indium ( III ) methoxyimino propionate resist .
• Features here are slightly smaller than the designed half pitch due to underdosing .
• Figure 8 shows the dose-to-gel curves of aluminium ( III ) methoxyimino propionate resist exposed to (a) EUV and (b) electron beam .
• Figure 8 ( c) shows the sensitivity values of the resist obtained with various developers .
• MeOH methanol
• 1M2P l-methoxy-2-propanol
• 3M1B 3-methoxy-l-butanol
• 2-MEA 2- methoxyethyl acetate .
• Figure 10 shows the dose-to-gel curves of nickel ( II ) methoxyimino propionate resist exposed to (a) EUV and (b) electron beam .
• Figure 10 ( c) shows the sensitivity values of the resist obtained with various developers . 'N/A' indicates that data could not be acquired due to no feature seen on the surface .
• Figure 11 shows the dose-to-gel curves of magnesium ( II ) methoxyimino propionate resist exposed to (a) EUV and (b) electron beam .
• Figure 11 ( c) shows the sensitivity values of the resist obtained with various developers . 'N/A' indicates that data could not be acquired due to no development at all .
• Figure 12 shows the dose-to-gel curves of tin ( II ) methoxyimino propionate resist exposed to (a) EUV and (b) electron beam .
• Figure 12 ( c) shows the sensitivity values of the resist obtained with various developers . indicates data from poor development characteristics . 'N/A' indicates that data could not be acquired due to excessive scum on the surface . Maj or advantages of the metal/metal compound Ketoacidoximate resist system include
• Resists are sub-5 nm lithography capable and possibly angstrom-scale lithography as well using an electron beam
• Figure 13 provides theoretically calculated EUV absorption cross-section of various elements .
• the data here provide guidelines for the choice of elements in EUV resists .
• Figure 14 shows EUVL Dose-to-Gel curves for a Zn (MIP) 2 . 2H2O Resist .
• EUV patterning results are presented with the Zn (MIP) 2 . 2H2O resist or the Zn (MIP) 2 (Anhydrous ) resist .
• Figure 15 illustrates the EUV patterning results for Zn (MIP) 2 . 2 H2O Resist without underlayer .
• Figure 16 depicts the EUV patterning results for Zn(MIP)2 (Anhydrous) also without an underlayer.
• Figure 17 illustrates the EUV patterning results for Zn(MIP)2 (Anhydrous) with an underlayer SHT101 while Figure 18 represents the EUV patterning results for Zn (MIP) 2 (Anhydrous) with underlayer SHT101 and and post-exposure bake at 80 °C and 60 sec.
• Figure 19 shows the EUV patterning results for Zn(MIP)2 (Anhydrous) with a different underlayer PRE102 and and a postexposure bake at 90 °C and 60 sec.
• Figure 20 depicts the EUV patterning results for Zn (MIP) 2.2 H2O Resist without underlayer and now with a different developer Anisole and Figure 21 shows the EUV patterning results for Zn(MIP)2 (Anhydrous) without underlayer and with the developer Anisole.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
• Materials For Photolithography (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 2022
  • 2022-09-22 EP EP22197213.6A patent/EP4343432A1/de not_active Withdrawn
• 2023
  • 2023-08-18 EP EP23761778.2A patent/EP4591121A1/de active Pending
  • 2023-08-18 JP JP2025517399A patent/JP2025531404A/ja active Pending
  • 2023-08-18 WO PCT/EP2023/072763 patent/WO2024061550A1/en not_active Ceased
  • 2023-08-18 KR KR1020257008992A patent/KR20250051090A/ko active Pending
  • 2023-08-18 CN CN202380064904.8A patent/CN119856118A/zh active Pending
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