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
  • G03F7/70—Microphotolithographic exposure; Apparatus therefor
  • G03F7/70008—Production of exposure light, i.e. light sources
  • G03F7/70033—Production of exposure light, i.e. light sources by plasma extreme ultraviolet [EUV] sources
• • 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
  • G03F7/0043—Chalcogenides; Silicon, germanium, arsenic or derivatives thereof; Metals, oxides or alloys thereof
• • 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
  • G03F7/20—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
  • G03F7/2014—Contact or film exposure of light sensitive plates such as lithographic plates or circuit boards, e.g. in a vacuum frame
• • 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
  • G03F7/36—Imagewise removal not covered by groups G03F7/30 - G03F7/34, e.g. using gas streams, using plasma
• • 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
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/60—Formation of materials, e.g. in the shape of layers or pillars of insulating materials
  • H10P14/63—Formation of materials, e.g. in the shape of layers or pillars of insulating materials characterised by the formation processes
  • H10P14/6302—Non-deposition formation processes
  • H10P14/6319—Formation by plasma treatments, e.g. plasma oxidation of the substrate
• • 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
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/60—Formation of materials, e.g. in the shape of layers or pillars of insulating materials
  • H10P14/69—Inorganic materials
  • H10P14/692—Inorganic materials composed of oxides, glassy oxides or oxide-based glasses
  • H10P14/6938—Inorganic materials composed of oxides, glassy oxides or oxide-based glasses the material containing at least one metal element, e.g. metal oxides, metal oxynitrides or metal oxycarbides
  • H10P14/6939—Inorganic materials composed of oxides, glassy oxides or oxide-based glasses the material containing at least one metal element, e.g. metal oxides, metal oxynitrides or metal oxycarbides characterised by the metal
  • H10P14/69392—Inorganic materials composed of oxides, glassy oxides or oxide-based glasses the material containing at least one metal element, e.g. metal oxides, metal oxynitrides or metal oxycarbides characterised by the metal the material containing hafnium, e.g. HfO2
• • 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
  • H10P50/00—Etching of wafers, substrates or parts of devices
  • H10P50/20—Dry etching; Plasma etching; Reactive-ion etching
  • H10P50/28—Dry etching; Plasma etching; Reactive-ion etching of insulating materials
  • H10P50/282—Dry etching; Plasma etching; Reactive-ion etching of insulating materials of inorganic materials
  • H10P50/283—Dry etching; Plasma etching; Reactive-ion etching of insulating materials of inorganic materials by chemical means
• • 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
  • H10P50/00—Etching of wafers, substrates or parts of devices
  • H10P50/20—Dry etching; Plasma etching; Reactive-ion etching
  • H10P50/28—Dry etching; Plasma etching; Reactive-ion etching of insulating materials
  • H10P50/286—Dry etching; Plasma etching; Reactive-ion etching of insulating materials of organic materials
  • H10P50/287—Dry etching; Plasma etching; Reactive-ion etching of insulating materials of organic materials by chemical means
• • 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
• • 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
  • H10P76/40—Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography of masks comprising inorganic materials
  • H10P76/408—Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography of masks comprising inorganic materials characterised by their sizes, orientations, dispositions, behaviours or shapes
  • H10P76/4085—Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography of masks comprising inorganic materials characterised by their sizes, orientations, dispositions, behaviours or shapes characterised by the processes involved to create the masks
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/32—Gas-filled discharge tubes
  • H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
  • H01J37/32082—Radio frequency generated discharge

Definitions

• the present disclosure relates to the processing of substrates.
• it provides a novel system and method for patterning EUV (or lower wavelength) photoresists.
• EUV lithography typically uses light having a wavelength from 6 to 16 nanometers (nm) or below.
• EUV patterning techniques have been introduced into production at sub-7 nm node advanced semiconductor device manufacturing. Although reduced feature sizes are achieved, pattern performance problems have occurred in EUV patterning.
• CARs Chemically amplified resists
• EUV lithography Chemically amplified resists
• Such resists have good sensitivity, the resolution of CARs is strongly affected by pattern collapse, which is increasingly important as feature sizes approach the nanometer scale.
• Metal-oxide photoresists have also been used in negative tone EUV lithography to transfer patterns onto one or more underlying layers formed on a substrate. Compared to CARs, metal-oxide photoresists offer the advantages of very thin film thicknesses and minimize the risk of pattern collapse. Although a promising replacement for CARs, conventional processes used to form metal-oxide photoresists utilize a wet process for pattern development. For example, metal-oxide photoresists may be developed using a wet organic developer in a negative tone photoresist process Though negative tone photoresists may be adequate for patterning line/space features and blocks, negative tone photoresists have not been satisfactory for patterning other features, such as holes or vias.
• Improved process flows and methods are provided herein for patterning extreme ultraviolet (EUV) or lower wavelength photoresists. More specifically, improved process flows and methods are provided herein for patterning metal-oxide photoresists, which may be used in EUV (or lower wavelength) lithography to transfer patterns onto one or more underlying layers formed on a substrate.
• a patterning layer comprising a metal-oxide photoresist is formed on one or more underlying layers provided on a substrate, and portions of the patterning layer not covered by a mask overlying the patterning layer are exposed to EUV or lower wavelength light.
• EUV or lower wavelength exposure separates organic ligands from metal-oxide structures (e.g., cages or chains) within the exposed portions of the metal-oxide photoresist, while leaving unexposed portions of the metal-oxide photoresist unchanged.
• a bake process is performed to release the organic ligands freed from the exposed portions of the metal- oxide photoresist, and a plasma process is used to remove (e.g., etch) the exposed portions to develop the metal-oxide photoresist pattern.
• the plasma process described herein may use a plurality of deposition and etch steps to develop the metal-oxide photoresist pattern.
• a hydrocarbon or fluorocarbon based plasma may be used in the deposition step to selectively deposit a protective layer (or film) onto the unexposed portions of the metal- oxide photoresist.
• a hydrogen or halogen based plasma may be used to selectively convert a surface of the exposed portions of the metal-oxide photoresist into a volatile material (e.g., a metal hydride, halide or chloride), which can be removed for example via ion bombardment.
• the protective layer selectively deposited onto the unexposed portions of the metal-oxide photoresist protects the unexposed portions from erosion, while the exposed portions of the metal-oxide photoresist are selectively etched during the etch step.
• the plasma development process described herein may continue in a cyclical manner, repeating the selective deposition and selective etch steps, until the exposed portions of the metal-oxide photoresist are completely removed.
• a method for patterning a substrate.
• the method may include forming a patterning layer and one or more underlying layers on the substrate, wherein the patterning layer comprises a metal-oxide photoresist, and performing an extreme ultraviolet (EUV) or lower wavelength lithography step, in which portions of the patterning layer not covered by an overlying mask are exposed to EUV or lower wavelength light.
• EUV extreme ultraviolet
• the method may include performing a cyclic, dry process to remove the portions of the patterning layer exposed to the EUV or lower wavelength light and develop a metal- oxide photoresist pattern.
• the cyclic, dry process may include selectively depositing a protective layer onto unexposed portions of the patterning layer by exposing the substrate to a first plasma, selectively etching exposed portions of the patterning layer by exposing the substrate to a second plasma, and repeating the selectively depositing and the selectively etching until the exposed portions of the patterning layer are completely removed.
• the unexposed portions of the patterning layer are portions that are covered by the overlying mask and not exposed to the EUV or lower wavelength light.
• the exposed portions of the patterning layer on the other hand, are not covered by the overlying mask and are exposed to the EUV or lower wavelength light.
• the first plasma and the second plasma may utilize a wide variety of precursor gas(es).
• the first plasma may comprise a hydrocarbon or fluorocarbon based precursor gas.
• the second plasma may comprise a hydrogen or halogen containing precursor gas and an inert gas.
• the hydrogen or halogen containing precursor gas converts a surface of the exposed portions of the patterning layer into a volatile material, and ions of the inert gas bombard a surface of the substrate to remove the volatile material from the exposed portions.
• a new protective layer is deposited onto the unexposed portions of the patterning layer.
• the method may include forming a patterning layer and one or more underlying layers on the substrate, wherein the patterning layer comprises a metal-oxide photoresist, and exposing portions of the patterning layer, which are not covered by a mask overlying the patterning layer, to extreme ultraviolet (EUV) or lower wavelength light.
• EUV extreme ultraviolet
• the method may include selectively depositing a protective layer onto unexposed portions of the patterning layer by exposing the substrate to a first plasma, selectively etching the exposed portions of the patterning layer by exposing the substrate to a second plasma, and repeating the selectively depositing and the selectively etching steps until the exposed portions of the patterning layer are completely removed.
• the patterning layer may comprise a metal-oxide material, which includes clusters of metal-oxide structures having chemically bound organic ligands.
• exposing the portions of the patterning layer not covered by the patterned mask layer to EUV or lower wavelength light separates the organic ligands from the metal-oxide structures, while leaving the unexposed portions of the patterning layer unchanged.
• the method may further include performing a bake process to release the organic ligands from the exposed portions of the patterning layer.
• the first plasma and the second plasma may utilize a wide variety of precursor gas(es).
• the first plasma may comprise a hydrocarbon or fluorocarbon based precursor gas.
• the first plasma may comprise CH 4 , C 4 F 8 , C 4 F 6 or CH 3 F.
• the second plasma may comprise a hydrogen or halogen containing precursor gas.
• the second plasma may comprise CH 4 , CF 4 .CHF 3 or BCl 3 .
• the second plasma may further comprise an inert gas.
• the second plasma may further comprise argon (Ar).
• the hydrogen or halogen containing precursor gas converts a surface of the exposed portions of the patterning layer into a volatile material, and the inert gas ions bombard the surface of the exposed portions to remove the volatile material.
• the steps of selectively depositing a protective layer onto unexposed portions of the patterning layer and selectively etching the exposed portions of the patterning layer are performed simultaneously within a plasma processing chamber using the same plasma precursor gases to generate the first plasma and the second plasma.
• the first plasma and the second plasma may each comprise a hydrocarbon precursor and an inert gas.
• the steps of selectively depositing a protective layer onto unexposed portions of the patterning layer and selectively etching the exposed portions of the patterning layer are segregated within a plasma processing chamber, so that different plasma precursor gases are used to generate the first plasma and the second plasma.
• the first plasma may comprise a hydrocarbon precursor
• the second plasma may comprise a halocarbon precursor and an inert gas.
• FIG. 1A-1 F illustrate an improved process flow for patterning a substrate, and more specifically, for patterning extreme ultraviolet (EUV) photoresists.
• FIG. 2 is a flowchart diagram illustrating one embodiment of a method for patterning a substrate.
• FIG. 3 is a flowchart diagram illustrating another embodiment of a method for patterning a substrate.
• FIG. 4 is a block diagram illustrating one embodiment of a plasma processing system that may be used to pattern a substrate using the techniques described herein.
• Improved process flows and methods are provided herein for patterning extreme ultraviolet (EUV) (or lower wavelength) photoresists. More specifically, improved process flows and methods are provided herein for patterning metal-oxide photoresists, which may be used in EUV or lower wavelength lithography to transfer patterns onto one or more underlying layers formed on a substrate.
• the process flows and methods disclosed herein may utilize a wide variety of metal-oxide materials including, but not limited to, metal-oxides comprising tin (Sn), hafnium (Hf) and zirconium (Zr).
• metal-oxide materials containing Sn, Hf or Zr are disclosed herein as examples, the process flows and methods disclosed herein are extendible to other metal-oxide materials and metal-containing photoresists.
• an example embodiment utilizing EUV wavelength light is discussed.
• the techniques utilized herein are not limited to EUV wavelengths. Further, the techniques may be particularly advantageous for EUV or lower wavelengths of light. Thus, though described in some examples herein with regard to EUV wavelengths, the techniques provided may also be applicable to EUV or lower wavelengths of light.
• a patterning layer comprising a metal-oxide photoresist is formed on one or more underlying layers provided on a substrate, and portions of the patterning layer not protected by a mask between the light source and the patterning layer are exposed to EUV light.
• EUV exposure separates organic ligands from metal-oxide structures (e.g., cages or chains) within the exposed portions of the metal-oxide photoresist, while leaving unexposed portions of the metal-oxide photoresist unchanged.
• a bake process is performed to release the organic ligands freed from the exposed portions of the metal- oxide photoresist, and a plasma process is used to remove (e.g., etch) the exposed portions to develop the metal-oxide photoresist pattern. In this manner a dry plasma develop of a metal-oxide photoresist is provided.
• the plasma process described herein may use a plurality of deposition and etch steps to develop the metal-oxide photoresist pattern.
• a hydrocarbon or fluorocarbon based plasma may be used in the deposition step to selectively deposit a protective layer (or film) onto the unexposed portions of the metal- oxide photoresist.
• a hydrogen or halogen based plasma may be used to selectively convert a surface of the exposed portions of the metal-oxide photoresist into a volatile material (e.g., a metal hydride, halide or chloride), which can be removed for example via ion bombardment.
• the protective layer selectively deposited onto the unexposed portions of the metal-oxide photoresist protects the unexposed portions from erosion, while the exposed portions of the metal-oxide photoresist are selectively etched during the etch step.
• the plasma development process described herein may continue in a cyclical manner, repeating the selective deposition and selective etch steps, until the exposed portions of the metal-oxide photoresist are completely removed.
• a novel plasma development process for a metal-oxide photoresist is disclosed herein for advanced EUV patterning.
• the plasma development process allows selective deposition and selective etch at molecular/atomic level through precise plasma process control.
• plasma precursors are chosen to selectively convert a surface of the EUV activated areas (i.e., the exposed portions of the metal-oxide photoresist) into a more volatile material (e.g., a metal hydride, halogen, or chloride) in the selective etch step, and to selectively deposit a protective layer on the un-activated areas (i.e., the unexposed portions of the metal-oxide photoresist) in the selective deposition step.
• a protective layer on the un-activated areas (i.e., the unexposed portions of the metal-oxide photoresist) in the selective deposition step.
• the plasma processing steps disclosed herein may be performed simultaneously within the plasma process chamber using the same plasma precursors for both deposition and etch steps. In other embodiments, the plasma processing steps may be segregated within the plasma process chamber, so that different plasma precursors can be used to perform the deposition and etch steps.
• FIG. 1A-1 F illustrate one embodiment of an improved process flow for patterning EUV metal-oxide photoresists according to the techniques disclosed herein. It will be recognized that the embodiment shown in FIGS. 1 A-1 F is merely exemplary and the techniques described herein may be applied to other process flows.
• substrate 100 includes a patterning layer 108 formed over one or more underlying layers, such as for example, a hard mask layer 106, a sacrificial carbon layer 104 and a base substrate 102.
• Base substrate 102 may be any substrate for which the use of patterned features is desirable.
• base substrate 102 may be a semiconductor substrate having one or more semiconductor processing layers formed thereon.
• base substrate 102 may be a substrate that has been subject to multiple semiconductor processing steps which yield a wide variety of structures and layers, all of which are known in the substrate processing art.
• Hard mask layer 106 and sacrificial carbon layer 104 may be formed from any of a wide variety of materials, as is known in the art.
• the hard mask layer 106 may be a spin on glass (SOG) layer and the sacrificial carbon layer 104 may be a spin on carbon (SOC) layer.
• SOG spin on glass
• SOC spin on carbon
• the patterning layer 108 shown in FIG. 1A may be formed from any of a wide variety of materials commonly used in EUV lithography.
• the patterning layer 108 may be a metal-oxide photoresist.
• the patterning layer 108 may comprise a metal-oxide material containing tin (Sn), hafnium (Hf) or zirconium (Zr). Other metal-oxide materials may also be used to implement the patterning layer 108.
• a metal-containing, non-oxide photoresist material may be used to implement the patterning layer 108.
• the patterning layer 108 may generally be formed using any of a wide variety of deposition processes. In some embodiments, for example, a spin coating process may be utilized to form the patterning layer 108. However, the techniques described herein are not limited to the method of forming the patterning layer 108.
• the patterning layer 108 comprises a metal-oxide material, which includes clusters of metal-oxide structures (M-O) having chemically bound organic ligands (L).
• M-O metal-oxide structures
• L organic ligands
• FIGS. 1 B-1C exposes portions of the patterning layer 108 to extreme ultraviolet (EUV) light to separate or free the organic ligands (L) from the metal-oxide structures (M-O), and performs a bake process to release the freed ligands from the EUV exposed portions of the patterning layer 108.
• EUV extreme ultraviolet
• a cyclical dry process is used to remove the EUV exposed portions of the patterning layer 108 and develop the metal-oxide photoresist pattern, as shown in FIGS. 1 D-1 F.
• a mask 110 is provided above the patterning layer 108 and an EUV lithography step is performed in FIG. 1 B.
• EUV lithography step shown in FIG. 1 B the exposed portions 114 of the patterning layer 108 (/.a, the portions of the patterning layer 108 not protected by the mask 110) are exposed to EUV light 112.
• EUV exposure separates the organic ligands (L) from the metal-oxide structures (M-O) within only the exposed portions 114 of the patterning layer 108, while leaving the unexposed portions 116 of the patterning layer 108 unchanged.
• a post exposure bake (FEB) process is performed to release the freed ligands from the exposed portions 114 of the patterning layer 108, leaving only dense metal-oxide structures (M-O) in the exposed portions 114, as shown in FIG. 1C.
• a dry process e.g., a plasma development process
• M-O dense metal-oxide structures
• FIGS. 1 D-1 F illustrate one embodiment of a plasma development process that may be used to develop a metal-oxide photoresist pattern in accordance with the techniques described herein.
• the disclosed plasma development process may generally include a plurality of deposition and etch steps.
• the plasma development process may begin by exposing the substrate 100 to a first plasma 118 to selectively deposit a protective layer 120 onto the unexposed portions 116 of the patterning layer 108, as shown in FIG. 1 D. After the protective layer 120 is formed on the unexposed portions 116, the substrate 100 is exposed to a second plasma 122 to selectively etch or remove the exposed portions 114 of the patterning layer 108, as shown in FIG. 1 E.
• the protective layer 120 protects the unexposed portions 116 of the patterning layer 108 from erosion, while the exposed portions 114 of the patterning layer 108 are selectively etched or removed during the selective etch step.
• the plasma development process shown in FIGS. 1 D and 1 E may continue in a cyclical manner, by repeating the selective deposition and selective etch steps a number of cycles and/or until the exposed portions 114 of the patterning layer 108 are completely removed, as shown in FIG. 1 F.
• the first plasma 118 may use a hydrocarbon or fluorocarbon based precursor gas chemistry to selectively deposit the protective layer 120 onto the unexposed portions 116 of the patterning layer 108.
• hydrocarbon and fluorocarbon based chemistries that may be used within the first plasma 118 include, but are not limited to, CH 4 , C 4 F 8 , C 4 F 6 or CH 3 F.
• Other hydrocarbon or fluorocarbon based chemistries may also be used in the selective deposition step shown in FIG. 1 D.
• the second plasma 122 may use a hydrogen or halogen containing precursor gas chemistry to convert a surface of the exposed portions 114 into a volatile material (e.g., a metal hydride, halide or chloride), and may use an inert gas (such as, e.g., argon) to selectively etch or remove the volatized surface via ion bombardment.
• a volatile material e.g., a metal hydride, halide or chloride
• an inert gas such as, e.g., argon
• Examples of hydrogen or halogen containing precursor gas chemistries that may be used within the second plasma 122 include, but are not limited to, hydrocarbons (e.g., CH 4 ), halocarbons (e.g., CF 4 , CHF 3 ) and other halogen based chemistries (e.g., BCb) commonly used in plasma etching.
• hydrocarbons e.g., CH 4
• halocarbons e.g., CF 4 , CHF 3
• other halogen based chemistries e.g., BCb
• a combination of a hydrocarbon precursor gas and an inert gas may be used to generate the second plasma 122.
• the second plasma 122 may include a halocarbon, hydrogen and inert gas combination.
• the hydrogen (or halogen) components included within the second plasma 122 facilitate etching by converting the surface of the metal oxide material within the exposed portions 114 into volatized metal hydrides, halides or chlorides, which are removed in one embodiment via ion bombardment.
• the selective etch step shown in FIG. 1 E may be performed as a single step by exposing the substrate 100 to a plasma containing a hydrogen (or halogen) containing precursor gas and an inert gas (such as argon).
• the selective etch step may be a cyclic process that exposes the substrate 100 to a hydrogen (or halogen) based plasma before exposing the substrate 100 to an argon plasma.
• inert gas ions may also be used to bombard the surface of the exposed portions 114 in the selective etch step shown in FIG. 1 D.
• exemplary inert gases include, but are not limited to He, Ne, Kr, and other noble gases.
• other gases may be utilized in combination with the argon and/or noble gases.
• other gases may be added to the plasma, as the plasma is not limited to only having argon or noble gases.
• other inert gases or other gases that are not inert gases may be added to the process.
• the selective deposition and selective etch steps shown in FIGS. 1 D and 1 E may be performed simultaneously within the plasma processing chamber, or alternatively, may be segregated into two plasma processing steps and separated for example by one or more purge steps.
• the selective deposition and etch steps may be performed simultaneously within the plasma process chamber using the same plasma precursors (e.g., CH 4 ) for both deposition and etch steps.
• the selective deposition and etch steps may be segregated within the plasma process chamber, so that different plasma precursors can be used in the deposition and etch steps.
• the selective deposition and etch steps may be segregated within the plasma process chamber, so that a hydrocarbon precursor (e.g., CH 4 ) can be used in the deposition step, while a hydrogen (H2), halocarbon (e.g., CF 4 or CHF 3 ) and halogen based chemistry (e.g., BCb) is used in the etch step.
• a hydrocarbon precursor e.g., CH 4
• H2 hydrogen
• halocarbon e.g., CF 4 or CHF 3
• BCb halogen based chemistry
• the selective deposition and etch steps shown in FIGS. 1 D and 1 E may be performed as a cyclic process, which is repeated a number of cycles until the exposed portions 114 of the patterning layer 108 are completely removed as shown in FIG. 1 F.
• Each time an etch step is performed some or all of the protective layer 120 formed on the unexposed portions 116 may be removed along with the volatized surface of the exposed portions 114. In one embodiment, a very thin protective layer may remain after each cycle.
• a new protective layer 120 is formed on the top and sides of the unexposed portions 116 as shown in FIG. 1 F.
• the plasma chemistries used in the selective deposition and etch steps described herein may generally be selective to the hard mask layer 106.
• the plasma development process shown in FIGS. 1 D-1F uses a cyclic, dry process for pattern development of positive tone photoresists. Unlike negative tone photoresists, positive tone photoresists can be used for hole, block and line/space patterning in narrow geometry processes.
• the plasma development process described herein provides atomic layer control of surface reactions and improves line edge roughness (LER) and critical dimension (CD) control compared to conventional wet process pattern development.
• the plasma development process described herein is also cleaner and more cost effective than conventional wet process pattern development.
• FIGS. 2-3 illustrate exemplary methods for patterning a substrate, which use the plasma development process described herein. It will be recognized that the embodiments of FIGS. 2-3 are merely exemplary and additional methods may utilize the techniques described herein. Further, additional processing steps may be added to the methods shown in the FIGS. 2-3 as the steps described are not intended to be exclusive. Moreover, the order of the steps is not limited to the order shown in the figures as different orders may occur and/or various steps may be performed in combination or at the same time. Further, though described with relation to EUV light, it will be recognized that the methods of FIGS. 2-3 may be advantageous for EUV or lower wavelengths of light.
• FIG. 2 illustrates one embodiment of a method 200 that may be used to pattern a substrate using the techniques disclosed herein.
• the method 200 may begin by forming a patterning layer and one or more underlying layers on the substrate, wherein the patterning layer comprises a metal-oxide photoresist (in step 210).
• the method 200 performs an extreme ultraviolet (EUV) lithography step, in which portions of the patterning layer not covered by an overlying mask are exposed to EUV light (in step 220).
• EUV extreme ultraviolet
• the method 200 performs a cyclic, dry process to remove the portions of the patterning layer exposed to the EUV light and develop the metal-oxide photoresist pattern.
• FIG. 3 illustrates another embodiment of a method 300 that may be used to pattern a substrate using the techniques disclosed herein.
• the method 300 may begin by forming a patterning layer and one or more underlying layers on the substrate, wherein the patterning layer comprises a metal-oxide photoresist (in step 310). After the patterning layer is formed, the method 300 exposes portions of the patterning layer, which are not covered by a mask overlying the patterning layer, to extreme ultraviolet (EUV) light (in step 320). In step 330, the method 300 selectively deposits a protective layer onto unexposed portions of the patterning layer by exposing the substrate to a first plasma.
• EUV extreme ultraviolet
• step 340 the method 300 selectively etches the exposed portions of the patterning layer by exposing the substrate to a second plasma.
• step 350 the method 300 repeats the selectively depositing and the selectively etching until the exposed portions of the patterning layer are completely removed.
• FIG. 4 provides one example embodiment for a plasma processing system 400 that can be used with respect to the disclosed techniques and is provided only for illustrative purposes.
• the plasma processing system 400 shown in FIG. 4 is a capacitively coupled plasma (CCP) processing apparatus
• CCP capacitively coupled plasma
• ICP inductively coupled plasma
• RSATM Radial Line Slot Antenna
• ECR electron cyclotron resonance
• the plasma processing system 400 can be used for a wide variety of operations including, but not limited to, etching, deposition, cleaning, plasma polymerization, plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), atomic layer etch (ALE), and so forth.
• PECVD plasma enhanced chemical vapor deposition
• ALD atomic layer deposition
• ALE atomic layer etch
• the structure of a plasma processing system 400 is well known, and the particular structure provided herein is merely of illustrative purposes. It will be recognized that different and/or additional plasma process systems may be implemented while still taking advantage of the techniques described herein.
• the plasma processing system 400 may include a process chamber 405.
• process chamber 405 may be a pressure controlled chamber.
• a substrate 410 in one example a semiconductor wafer
• a stage or chuck 415 may be held on a stage or chuck 415.
• An upper electrode 420 and a lower electrode 425 may be provided as shown.
• the upper electrode 420 may be electrically coupled to a first radio frequency (RF) source 430 through a first matching network 455.
• the first RF source 430 may provide a source voltage 435 at an upper frequency (f L ).
• the lower electrode 425 may be electrically coupled to a second RF source 440 through a second matching network 457.
• the second RF source 440 may provide a bias voltage 445 at a lower frequency (f L ).
• a voltage may also be applied to the chuck 415.
• Components of the plasma processing system 400 can be connected to, and controlled by, a control unit 470 that in turn can be connected to a corresponding memory storage unit and user interface (all not shown).
• Various plasma processing operations can be executed via the user interface, and various plasma processing recipes and operations can be stored in a storage unit. Accordingly, a given substrate can be processed within the plasma processing chamber with various microfabrication techniques.
• control unit 470 may be coupled to various components of the plasma processing system 400 to receive inputs from and provide outputs to the components.
• the control unit 470 can be implemented in a wide variety of manners.
• the control unit 470 may be a computer.
• the control unit may include one or more programmable integrated circuits that are programmed to provide the functionality described herein.
• one or more processors e.g., microprocessor, microcontroller, central processing unit, etc.
• programmable logic devices e.g., complex programmable logic device (CPLD)), field programmable gate array (FPGA), etc.
• CPLD complex programmable logic device
• FPGA field programmable gate array
• other programmable integrated circuits can be programmed with software or other programming instructions to implement the functionality of a proscribed plasma process recipe.
• the software or other programming instructions can be stored in one or more non-transitory computer-readable mediums (e.g., memory storage devices, FLASH memory, dynamic random access (DRAM) memory, reprogrammable storage devices, hard drives, floppy disks, DVDs, CD-ROMs, etc.), and the software or other programming instructions when executed by the programmable integrated circuits cause the programmable integrated circuits to perform the processes, functions, and/or capabilities described herein. Other variations could also be implemented.
• non-transitory computer-readable mediums e.g., memory storage devices, FLASH memory, dynamic random access (DRAM) memory, reprogrammable storage devices, hard drives, floppy disks, DVDs, CD-ROMs, etc.
• the plasma processing system 400 uses the upper and lower electrodes to generate a plasma 460 in the process chamber 405 when applying power to the system from the first RF source 430 and the second RF source 440.
• the application of power results in a high-frequency electric field being generated between the upper electrode 420 and the lower electrode 425.
• Processing gas(es) delivered to process chamber 405 can then be dissociated and converted into a plasma 460.
• the generated plasma 460 can be used for processing a target substrate (such as substrate 410 or any material to be processed) in various types of treatments such as, but not limited to, plasma deposition, etching and/or ion bombardment/sputtering.
• the selective deposition and etch steps disclosed herein may be performed simultaneously using the same plasma 460.
• a hydrocarbon (such as CH 4 ) based plasma 460 may be utilized to selectively deposit a protective layer on the unexposed portions 116 and selectively etch the exposed portions 114 of the patterning layer 108.
• the selective deposition and etch steps disclosed herein may use different plasmas 460, which are segregated within the process chamber 405 for example by one or more purge steps.
• the exemplary plasma processing system 400 described herein utilizes two RF sources.
• the first RF source 430 provides source power at relatively high frequencies to convert the processing gas(es) delivered into the process chamber 405 into plasma and to control the plasma density
• the second RF source 440 provides a bias power at lower frequencies to control ion bombardment energy.
• the first RF source 430 may provide about 0 to 1400 W of source power in a high-frequency (HF) range from about 3 MHz to 150 MHz (or above) to the upper electrode 420
• the second RF source 440 may provide about 0 to 1400 W of bias power in a low-frequency (LF) range from about 0.2 MHz to 60 MHz to the lower electrode 425.
• HF high-frequency
• LF low-frequency
• Different operational ranges can also be used depending on type of plasma processing system and the type of treatments (e.g., etching, deposition, sputtering, etc.) performed therein.
• the first plasma 118 used in the deposition step shown in FIG. 1 D may be performed with process conditions of 50 Wto 1000 W source power, 0 W to 200 W bias power, 10 mT to 200 mT pressure, 0° C to 150° C electrostatic chuck temperature, and 50 standard cubic centimeters (SCCM) of CH 4 gas flow.
• Other gases such as for example, CH 3 F, CH 2 F 2 , etc. may also be used in the gas flow.
• the second plasma 122 used in the etch step shown in FIG. 1 E may be performed with process conditions of 50 Wto 1000 W source power, 0 W to 200 W bias power, 10 mT to 200 mT pressure, 10° C to 150° C electrostatic chuck temperature, and 20 to 100 standard cubic centimeters (SCCM) of CH 4 gas flow.
• gases such as for example, Cb. BCb, inert gases, etc. may also be used in the gas flow.
• the bias power may be adjusted or controlled to control the ion bombardment energy during the etch step.
• a separate surface activation/ion bombardment step may be performed with process conditions of 100 W to 500 W source power, 0 W to 200 W bias power, 10 mT to 200 mT pressure, 10° C to 200° C electrostatic chuck temperature, and 800 standard cubic centimeters (SCCM) of Ar gas flow.
• Other gases such as for example, He, Ne, Kr, etc. may also be used in the gas flow.
• the techniques described herein may be utilized within a wide range of plasma processing systems. Although a particular plasma processing system 400 is shown in FIG. 4, it will be recognized that the techniques described herein may be utilized within other plasma processing systems. In one example system, the RF sources shown in FIG. 4 may be switched (e.g., higher frequencies may be supplied to the lower electrode 425 and lower frequencies may be supplied to the upper electrode 420). Further, a dual source system is shown in FIG. 4 merely as an example system. It will be recognized that the techniques described herein may be utilized with other plasma processing systems in which a modulated RF power source is provided to one or more electrodes, direct current (DC) bias sources are utilized, or other system components are utilized.
• DC direct current
• deposition processes can be used to form one or more of the material layers shown and described herein.
• one or more depositions can be implemented using chemical vapor deposition (CVD), plasma enhanced CVD (PECVD), physical vapor deposition (PVD), atomic layer deposition (ALD), and/or other deposition processes.
• CVD chemical vapor deposition
• PECVD plasma enhanced CVD
• PVD physical vapor deposition
• ALD atomic layer deposition
• a precursor gas mixture can be used including but not limited to hydrocarbons and fluorocarbons, possibly in combination with one or more dilution gases (e.g., argon, nitrogen, etc.) at a variety of pressure, power, flow and temperature conditions.
• dilution gases e.g., argon, nitrogen, etc.
• etch processes can be used to etch one or more of the material layers shown and described herein.
• one or more etch processes can be implemented using plasma etch processes, discharge etch processes, and/or other desired etch processes.
• the plasma etch processes described herein can be implemented using plasma containing hydrogen, halocarbons and other halogen containing chemistries, argon and/or other gases.
• one or more operational parameters (e.g., bias power) of the plasma etch processes described herein may be tuned to control the ion bombardment energy during the etch step.
• operating variables for process steps can also be adjusted to control the various deposition and/or etch processes described herein.
• the operating variables may include, for example, the chamber temperature, chamber pressure, flowrates of gases, types of gases, and/or other operating variables for the processing steps. Variations can also be implemented while still taking advantage of the techniques described herein.
• substrate means and includes a base material or construction upon which materials are formed. It will be appreciated that the substrate may include a single material, a plurality of layers of different materials, a layer or layers having regions of different materials or different structures in them, etc. These materials may include semiconductors, insulators, conductors, or combinations thereof.
• the substrate may be a semiconductor substrate, a base semiconductor layer on a supporting structure, a metal electrode or a semiconductor substrate having one or more layers, structures or regions formed thereon.
• the substrate may be a conventional silicon substrate or other bulk substrate comprising a layer of semi-conductive material.
• the term “bulk substrate” means and includes not only silicon wafers, but also silicon-on-insulator (“SOI”) substrates, such as silicon-on-sapphire (“SOS”) substrates and silicon-on-glass (“SOG”) substrates, epitaxial layers of silicon on a base semiconductor foundation, and other semiconductor or optoelectronic materials, such as silicon-germanium, germanium, gallium arsenide, gallium nitride, and indium phosphide.
• SOI silicon-on-insulator
• SOS silicon-on-sapphire
• SOOG silicon-on-glass
• epitaxial layers of silicon on a base semiconductor foundation and other semiconductor or optoelectronic materials, such as silicon-germanium, germanium, gallium arsenide, gallium nitride, and indium phosphide.
• the substrate may be doped or undoped.
• the substrate may include any material portion or structure of a device, particularly a semiconductor or other electronics device, and may, for example, be a base substrate structure, such as a semiconductor substrate or a layer on or overlying a base substrate structure such as a thin film.
• substrate is not intended to be limited to any particular base structure, underlying layer or overlying layer, patterned or unpattemed, but rather, is contemplated to include any such layer or base structure, and any combination of layers and/or base structures.

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