WO2020216571A1 - Support de substrat destiné à être utilisé dans un appareil lithographique - Google Patents

Support de substrat destiné à être utilisé dans un appareil lithographique Download PDF

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Publication number
WO2020216571A1
WO2020216571A1 PCT/EP2020/058474 EP2020058474W WO2020216571A1 WO 2020216571 A1 WO2020216571 A1 WO 2020216571A1 EP 2020058474 W EP2020058474 W EP 2020058474W WO 2020216571 A1 WO2020216571 A1 WO 2020216571A1
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WO
WIPO (PCT)
Prior art keywords
burls
substrate holder
substrate
group
hard layer
Prior art date
Application number
PCT/EP2020/058474
Other languages
English (en)
Inventor
Lucas Henricus Johannes Stevens
Nicolaas Ten Kate
Original Assignee
Asml Netherlands B.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Asml Netherlands B.V. filed Critical Asml Netherlands B.V.
Publication of WO2020216571A1 publication Critical patent/WO2020216571A1/fr

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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
    • G03F7/70691—Handling of masks or workpieces
    • 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
    • G03F7/70691—Handling of masks or workpieces
    • G03F7/707—Chucks, e.g. chucking or un-chucking operations or structural details
    • 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
    • G03F7/70691—Handling of masks or workpieces
    • G03F7/707—Chucks, e.g. chucking or un-chucking operations or structural details
    • G03F7/70708—Chucks, e.g. chucking or un-chucking operations or structural details being electrostatic; Electrostatically deformable vacuum chucks
    • 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
    • G03F7/70691—Handling of masks or workpieces
    • G03F7/70716—Stages
    • 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
    • G03F7/70691—Handling of masks or workpieces
    • G03F7/70783—Handling stress or warp of chucks, masks or workpieces, e.g. to compensate for imaging errors or considerations related to warpage of masks or workpieces due to their own weight
    • 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
    • G03F7/708—Construction of apparatus, e.g. environment aspects, hygiene aspects or materials
    • G03F7/70808—Construction details, e.g. housing, load-lock, seals or windows for passing light in or out of apparatus
    • G03F7/70825—Mounting of individual elements, e.g. mounts, holders or supports
    • 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
    • G03F7/708—Construction of apparatus, e.g. environment aspects, hygiene aspects or materials
    • G03F7/7095—Materials, e.g. materials for housing, stage or other support having particular properties, e.g. weight, strength, conductivity, thermal expansion coefficient
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/687—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches
    • H01L21/68714—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support
    • H01L21/6875—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support characterised by a plurality of individual support members, e.g. support posts or protrusions
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/687—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches
    • H01L21/68714—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support
    • H01L21/68757—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support characterised by a coating or a hardness or a material

Definitions

  • the present invention relates to a lithographic apparatus, in particular a substrate holder for use in a lithographic apparatus.
  • a lithographic apparatus is a machine constructed to apply a desired pattern onto a substrate.
  • a lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs).
  • a lithographic apparatus may, for example, project a pattern (also often referred to as“design layout” or “design”) of a patterning device (e.g., a mask) onto a layer of radiation- sensitive material (resist) provided on a substrate (e.g., a wafer).
  • the substrate is clamped onto a substrate holder in the lithographic apparatus when transferring a pattern from the patterning device.
  • the substrate holder conventionally has a plurality of burls to support the substrate.
  • the total area of the burls that contacts the substrate is small compared to the total area of a substrate. Therefore, the chance that a contaminant particle randomly located on the surface of the substrate or the substrate holder is trapped between a burl and the substrate is small.
  • the tops of the burls can be made more accurately coplanar than a large surface can be made accurately flat.
  • the substrate holder can be made of electrically conducting, or alternatively, electrically insulating material. A material that can readily be machined to a shape using conventional manufacturing methods is desirable. However, when substrates are loaded and unloaded from the substrate holder, the material of the substrate holder can wear quickly.
  • the hard layer may be composed of diamond-like carbon (DLC), or similar material.
  • the hard layer may be localized on the distal ends of each burl, such that the hard layer portions on each burl are materially separate from each other.
  • the hard layer may be electrically conductive.
  • substrate holder for use in a lithographic apparatus and configured to support a substrate
  • the substrate holder comprising: a main body formed of a conductive material and having a main body surface; a plurality of burls projecting from the main body surface and each having a distal end surface which substantially conforms to a support plane and is configured for supporting the substrate; an insulation layer disposed on at least the distal ends of a group of the burls; and
  • a hard layer disposed on the insulation layer and localised to the distal ends of the group of burls, wherein the hard layer is resistant to wear.
  • a substrate holder for use in a lithographic apparatus and configured to support a substrate
  • the substrate holder comprising: a main body formed of an insulating material and having a main body surface; a plurality of burls projecting from the main body surface and each having a distal end surface which substantially conforms to a support plane and is configured for supporting the substrate; a hard layer disposed on and localised to the distal ends of the group of burls, wherein the hard layer is resistant to wear, wherein: the resistance between any two burls of the group of burls is at least 100 MW, the electrical resistance being measurable at the hard layer localised on said any two burls.
  • a lithographic device manufacturing method comprising use of a substrate holder, said substrate holder configured to support a substrate, the substrate holder comprising: a main body formed of an insulating material and having a main body surface; a plurality of burls projecting from the main body surface and each having a distal end surface which substantially conforms to a support plane and is configured for supporting the substrate; a hard layer disposed on and localised to the distal ends of the group of burls, wherein the hard layer is resistant to wear, wherein: the resistance between any two burls of the group of burls is at least 100 MW, the electrical resistance being measurable at the hard layer localised on said any two burls.
  • Figure 1 schematically depicts a lithographic apparatus
  • Figure 2 depicts a top-down view of a substrate holder
  • Figure 3 depicts substrate surface charge as a product of substrate rinsing;
  • Figures 4 and 5 schematically depict embodiments of the substrate holder.
  • the terms“radiation” and“beam” are used to encompass all types of electromagnetic radiation, including ultraviolet radiation (e.g. with a wavelength of 365, 248, 193, 157 or 126 nm) and extreme ultraviolet (EUV) radiation (e.g. with a wavelength around 13 nm).
  • ultraviolet radiation e.g. with a wavelength of 365, 248, 193, 157 or 126 nm
  • EUV extreme ultraviolet
  • the term“reticle”,“mask” or“patterning device” as employed in this text may be broadly interpreted as referring to a generic patterning device that can be used to endow an incoming radiation beam with a patterned cross-section, corresponding to a pattern that is to be created in a target portion of the substrate.
  • the term“light valve” can also be used in this context.
  • examples of other such patterning devices include a programmable mirror array and a programmable LCD array.
  • FIG. 1 schematically depicts a lithographic apparatus LA of an embodiment.
  • the lithographic apparatus LA comprises:
  • an illumination system (illuminator) IL configured to condition a radiation beam B (e.g. UV radiation or DUV radiation);
  • a patterning device support structure e.g. a mask table
  • T usually comprising a reticle clamp constructed to support a patterning device (e.g. a mask) MA, and connected to a first positioner PM configured to accurately position the patterning device MA in accordance with certain parameters;
  • a support table e.g. a sensor table to support one or more sensors or a substrate table or wafer table WT constructed to hold a substrate (e.g. a resist-coated production substrate) W, connected to a second positioner PW configured to accurately position the surface of the table, for example of a substrate W, in accordance with certain parameters; and
  • a projection system e.g. a refractive projection lens system
  • PS configured to project a pattern imparted to the radiation beam B by patterning device MA onto a target portion C (e.g.
  • the illuminator IL receives a radiation beam from a radiation source SO, e.g. via a beam delivery system BD.
  • the illumination system IL may include various types of optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic, and/or other types of optical components, or any combination thereof, for directing, shaping, and or controlling radiation.
  • the illuminator IL may be used to condition the radiation beam B to have a desired spatial and angular intensity distribution in its cross section at a plane of the patterning device MA.
  • projection system PS used herein should be broadly interpreted as encompassing various types of projection system, including refractive, reflective, catadioptric, anamorphic, magnetic, electromagnetic and/or electrostatic optical systems, or any combination thereof, as appropriate for the exposure radiation being used, and/or for other factors such as the use of an immersion liquid or the use of a vacuum. Any use of the term“projection lens” herein may be considered as synonymous with the more general term“projection system”.
  • the lithographic apparatus LA may be of a type having two or more support tables, e.g., two or more support tables or a combination of one or more support tables and one or more cleaning, sensor or measurement tables.
  • the lithographic apparatus LA is a multi-stage apparatus comprising two or more tables located at the exposure side of the projection system PS, each table comprising and or holding one or more objects.
  • one or more of the tables may hold a radiation- sensitive substrate.
  • one or more of the tables may hold a sensor to measure radiation from the projection system.
  • the multi-stage apparatus comprises a first table configured to hold a radiation-sensitive substrate (i.e., a support table) and a second table not configured to hold a radiation-sensitive substrate (referred to hereinafter generally, and without limitation, as a measurement, sensor and or cleaning table).
  • the second table may comprise and/or may hold one or more objects, other than a radiation-sensitive substrate.
  • Such one or more objects may include one or more selected from the following: a sensor to measure radiation from the projection system, one or more alignment marks, and or a cleaning device (to clean, e.g., the liquid confinement structure).
  • the radiation beam B is incident on the pattern (design layout) present on patterning device (e.g., mask) MA, which is held on the support structure (e.g., mask table) T, and is patterned by the patterning device MA. Having traversed the patterning device MA, the radiation beam B passes through the projection system PS, which focuses the beam onto a target portion C of the substrate W.
  • the substrate table WT can be moved accurately, e.g. so as to position different target portions C in the path of the radiation beam B at a focused and aligned position.
  • first positioner PM and another position sensor can be used to accurately position the patterning device MA with respect to the path of the radiation beam B.
  • Patterning device MA and substrate W may be aligned using patterning device alignment marks Ml, M2 and substrate alignment marks PI, P2.
  • substrate alignment marks PI, P2 as illustrated occupy dedicated target portions C, they may be located in spaces between target portions C (these are known as scribe-lane alignment marks).
  • the substrate table WT comprises a substrate holder 60.
  • Figure 2 depicts a substrate holder 60 for use in the lithographic apparatus LA according to an embodiment.
  • the substrate holder 60 is for supporting the substrate W.
  • the substrate holder 60 comprises a main body 21.
  • the main body 21 has a main body surface 22.
  • a plurality of burls 20 are provided projecting from the main body surface 22.
  • the distal end surface of each burl 20 engages with the substrate W.
  • the distal end surfaces of the burls 20 are coplanar, i.e. the distal end surfaces of the burls 20 substantially conform to a support plane SP and support the substrate W.
  • the main body 21 may be formed of SiC, SiSiC, silicon oxides, silicon nitrides, silicon carbides, aluminium oxides, ceramics or combinations thereof.
  • the burls 20 may be formed of the same material as the main body 21, or may be formed of a different material.
  • Burls 20 may have a height in the range of from 10 pm to 500 pm, e.g. about 150 pm.
  • the diameter of the distal end surface of burl 20 may be in the range from 100 pm to 300 pm, e.g. about 200 pm.
  • the pitch of the burls 20 may be in the range from about 0.5 mm to 3 mm, e.g. about 1.5 mm.
  • the pitch of the burls 20 is the distance between the centers of two adjacent burls 20.
  • the total area of the distal end surfaces of all the burls 20 may be in the range of from 1% to 3% of the total area of the substrate holder 60.
  • Burls 20 may be frusto-conical in shape, with burl side surfaces being slightly inclined. Alternatively, the burl side surfaces may be vertical or even overhanging. Burls 20 may be circular in plan. Alternatively, burls 20 can also be formed in other shapes if desired.
  • a hard layer may be disposed on the at least some of the burls, said hard layer localised to the distal ends of those burls.
  • the hard layer may comprise a plurality of materially-separated hard layer portions localized to the distal ends of the burls.
  • the hard layer may be composed of: CrN, TiN aluminium oxides, diamond, diamond-like carbon, doped diamond-like carbon, cubic boron nitride, silicon carbide or chromium nitride, alloys containing one or more of Ti, W and Mo, or combinations thereof.
  • a plurality of through-holes 89 may be formed in the main body 21.
  • Through-holes 89 allow the e-pins to project through the substrate holder 60 to receive the substrate W.
  • Through-holes 89 may also allow the space between the substrate W and the substrate holder 60 to be evacuated. Evacuation of the space between the substrate W and the substrate holder WT can provide a clamping force, if the space above the substrate W is not also evacuated. The clamping force holds the substrate W in place. If the space above the substrate W is also evacuated, as would be the case in a lithographic apparatus using EUV radiation, electrodes can be provided on the substrate holder 60 to form an electrostatic clamp.
  • the substrate holder 60 can be provided with electronic components. Electronic components may comprise heaters and sensors. Heaters and sensors may be used to control the temperature of the substrate holder 60 and substrate W.
  • Figure 3 depicts a substrate rinsing process in diagram 330, a surface charge resulting on the substrate W from said process in diagram 310, and typical oxidation patterns occurring on the substrate holder 60 due to use in diagram 320.
  • the inventors have found that the features of the substrate rinsing process correspond with the pattern of backside charge on the substrate W, and have also found that said backside charge corresponds to oxidation patterns on the substrate holder 60.
  • the features of the substrate W correspond in a vertical fashion.
  • the guide lines 332a indicating a location on the substrate W correspond across the three diagrams 310, 320 and 330.
  • Diagram 330 depicts such a substrate rinsing process, specifically, a spin rinsing process (SRS).
  • SRS spin rinsing process
  • the substrate W is rotated at high speeds while a stream of liquid 331, for example ultra-pure water (UPW), is applied to the substrate W with a nozzle 332.
  • UPW ultra-pure water
  • the high speed rotation of the substrate W while the stream of liquid 331 is applied facilitates the even distribution of the liquid across the backside of the substrate W.
  • Nozzle 332 should not be considered as limiting to a nozzle component.
  • the location of the nozzle 332 can also indicate the starting point of an applied liquid stream 331, or the location at which the substrate W experiences the highest liquid pressure from the liquid stream 331.
  • Diagram 310 depicts the local charge along the diameter of the backside of the substrate W following rinsing.
  • the horizontal axis indicates the displacement along the diameter of the substrate, and the vertical axis indicates the local charge at that point along the substrate diameter.
  • the level 311 on the vertical axis indicates a neutral charge level. Local charge above this line will lead to material reduction, while local charge below this line will lead to material oxidation.
  • Guide lines 332a indicate that the troughs 312 in the substrate backside charge along the diameter of substrate W correspond to the location of the nozzle 332 during the rinsing process. In other words, the troughs 312 in substrate backside charge following rinsing occur at the location of the nozzle 332 during the rinsing step.
  • Figure 3 shows uncontrolled surface charge developing on the substrate backside due to substrate rinsing
  • uncontrolled surface charge may develop on any surface of the substrate due to other mechanisms such as charging due to other substrate cleaning methods (eg: scrubber clean process); charging due to other process steps such as dry etch, pre-clean, ion implantation, exposure, or pattern-induced charging effects (electron shading in uniform and non-uniform plasma); or charging due to other mechanisms such as high plasma density etc.
  • the present disclosure is not limited to uncontrolled surface charge developing on the substrate due to substrate rinsing, and descriptions specific to substrate rinsing are made by means of example only. It will be appreciated that the disclosure is applicable to uncontrolled surface charge arising from any mechanism.
  • Diagram 320 shows an oxidation pattern occurring on a substrate holder after substantial use.
  • the darker regions 322 in the diagram 320 indicate the areas on a substrate holder that experience more oxidation. These regions 332 may indicate the areas on a substrate holder that experience the most oxidation.
  • the regions 332 on the substrate holder 60 correspond to the troughs 312 in surface charge of the substrate W.
  • the regions 332 in which the substrate holder 60 experiences more oxidation correspond to the locations wherein the substrate W placed on the substrate holder 60 had higher levels of local negative surface charge on the backside.
  • the location of said high levels of negative surface charge on the substrate W backside correspond to the location of the nozzle 332. Therefore the location of nozzle 332 corresponds with the regions 322.
  • the surface charge on the substrate W may be transferred to the substrate holder 60.
  • the surface of the substrate is typically composed on an electrically insulating material such as S1O2 or SiN, this charge may be maintained on the surface of the substrate until it is loaded onto the substrate holder. Accordingly, when a substrate with surface charge is loaded onto the substrate holder, for example during a lithographic process, this charge may transfer to the substrate holder.
  • the inventors have found that this charge on the substrate holder will increase the rate of electrochemical oxidation occurring on the substrate holder.
  • the local environment of the substrate and substrate holder in the lithographic apparatus may have a high humidity, which exacerbates this process.
  • This oxidation process may occur on the burls 20 of the substrate holder, on the hard layer localized on the burls 20, on the main body surface 22 of the substrate holder or any combination of these locations on the substrate holder.
  • the present invention provides a substrate holder configured such that any two burls have at least a minimum resistance between them.
  • the substrate holder of the present invention is configured such that the capacitance between any two burls of the group of burls have less than a maximum capacitance between them. .
  • the selection of at least a minimum resistance between the burls mitigates the oxidation process as will be explained below.
  • the irregular surface charge profile of the substrate W can be transferred onto the substrate holder 60, either directly through conduction, or via capacitance. Regardless of how this charge is transferred to the substrate holder 60, the charge imbalance on the substrate holder causes currents to flow to correct the imbalance. This potential difference leads to enhanced electrochemical oxidation. Therefore, if this potential difference can be stopped or substantially reduced, the rate of oxidation of the substrate holder 60 can also be reduced.
  • oxidation of the substrate holder 60 can be limited, even after the surface charge of the substrate W has been transferred to the substrate holder 60, by introducing a minimum resistance between a group of the burls on the substrate holder 60. Uneven surface charge originating from the substrate W is first transferred to the portions of the substrate holder 60 which are contacting the substrate W - namely the distal ends of the burls. Therefore, each burl experiences a charge corresponding to the local charge of the portion of substrate W that it is contacting. Given the uneven surface charge profile of the substrate W, the burls will accordingly each experience a different charge. Therefore, if an electrical path between the burls exists, current will flow between them. However, if the resistance between each of the burls is increased, any current flowing between these burls is reduced. Thus electrochemical oxidation of the substrate holder 60 is also reduced.
  • a substrate holder of an embodiment may comprise: a main body formed of a conductive material and having a main body surface; a plurality of burls projecting from the main body surface and each having a distal end surface which substantially conforms to a support plane and is configured for supporting the substrate; an insulation layer disposed on at least the distal ends of a group of the burls; and a hard layer disposed on the insulation layer and localised to the distal ends of the group of burls, wherein the hard layer is resistant to wear.
  • the insulation layer can be configured such that it provides electrical resistance between a group of the burls.
  • the resistance between any two burls of the group of burls may be at least 100 MW, desirably at least 500 MW, desirably at least 1 ⁇ W, the electrical resistance being measurable at the hard layer localised on said any two burls.
  • the insulation layer may be made from at least one material selected from the group consisting of: SiC, SiSiC, silicon oxides, silicon nitrides, silicon carbides or an aluminium oxide or combinations thereof.
  • the insulation layer may be at least 2 nm thick.
  • the hard layer may be made from at least one material selected from the group consisting of: CrN, TiN aluminium oxides, diamond, diamond-like carbon, doped diamond-like carbon, cubic boron nitride, silicon carbide or chromium nitride, alloys containing one or more of Ti, W and Mo, or combinations thereof.
  • the insulation layer can be configured such that it provides a capacitance between a group of the burls.
  • the capacitance between any two burls of the group of burls may be less than 10 nF, desirably less than InF, desirably less than lOOpF, the capacitance being measurable between the hard layer localised on said any two burls.
  • a combination of a minimum resistance and a maximum capacitance between any two burls of the group of burls may be selected to yield a particular resistor-capacitor (RC) time constant.
  • the resistance and/or capacitance for the RC time constant may be measurable at the hard layer localised on said any two burls.
  • the resistance and or capacitance for the RC time constant may be measurable between the hard layer localized on the distal ends of the burls and the main body of the substrate table WT.
  • the capacitance may be measurable between the main body of the substrate holder, and a substrate held by the substrate holder.
  • the capacitance may be measurable between a burl 20 and the substrate W.
  • the RC time constant may be selected to be at least 10 seconds, desirably at least 100 seconds, desirably at least 1000 seconds.
  • Other resistances and/or capacitances pertaining to other portions of the substrate holder and/or substrate may be selected.
  • a combination of a resistance and a capacitance pertaining to other portions of the substrate holder and or substrate may be selected to yield a particular RC time constant.
  • the group of the burls may comprise all of the plurality of burls. Equally, any reference to a configuration of“the burls” in the disclosure may be understood as referring to only a group of the burls, or all of the burls. If the profile of the surface charge of the substrate W is predictable, the group of the burls may comprise only the burls that experience a high level of local surface charge.
  • the group of the burls comprises all of the burls regardless.
  • a substrate holder of an embodiment may alternatively comprise: a main body formed of an insulating material and having a main body surface; a plurality of burls projecting from the main body surface and each having a distal end surface which substantially conforms to a support plane and is configured for supporting the substrate; a hard layer disposed on and localised to the distal ends of the group of burls, wherein the hard layer is resistant to wear, wherein: the resistance between any two burls of the group of burls is at least 100 MW, desirably at least 500 MW, desirably at least 1 WW, the electrical resistance being measurable at the hard layer localised on said any two burls.
  • burls and hard layer and the materials from which they are formed, it may not be necessary to have an insulating layer.
  • the group of the burls may comprise all of the plurality of burls. If the profile of the surface charge of the substrate W is predictable, the group of the burls may comprise only the burls that experience a high level of local surface charge. However, even if the profile of the surface charge is predictable, it may be preferable that the group of the burls comprises all of the burls regardless.
  • Figures 4 and 5 show cross-sectional views of the substrate holder 60 according to embodiments of the invention.
  • the substrate holder 60 depicted in Figures 4 and 5 is a support structure for supporting an object, in particular, a substrate holder 60 for supporting a substrate W.
  • FIG. 4 shows a first configuration of the substrate holder 60 according to an embodiment of the invention.
  • Substrate holder 60 comprises a main body 21 with a main body surface 22, a plurality of burls 20 projecting from the main body surface 22, an insulation layer 401 and a hard layer 402 defining a plurality of hard layer portions 402’ .
  • the main body 21 of the substrate holder 60 may be made of an electrically conductive material.
  • the insulation layer 401 is disposed on at least the distal ends of a group of the burls.
  • the insulation layer may also be disposed on the sides of the burls, and/or the main body surface 22 between the burls 20.
  • the insulation layer may be of a uniform thickness.
  • the insulation layer may be made from at least one material selected from the group consisting of: SiC, SiSiC, silicon oxides, silicon nitrides, silicon carbides or an aluminium oxide or combinations thereof.
  • An adhesive layer may be disposed between the insulation layer 401 and the main body surface 22.
  • the hard layer 402 is disposed on the insulation layer 401, localized to the distal ends of a group of the burls.
  • the hard layer 402 may accordingly comprise of a plurality of materially-separated hard layer portions 402’.
  • Each of the hard layer portions 402’ may have a diameter less than that of the distal ends of the underlying burls 20, substantially equal to the diameter of the distal ends of the underlying burls, or greater than the diameter of the distal ends of the underlying burls.
  • Each of the hard layer portions 402’ may comprise a lip overhanging the distal end of the burls, and covering some portion of the side of the burls.
  • the distance between the centers of two adjacent hard layer portions 402’ may be equal to the pitch of the burls, and for example be about 0.5 mm to 3 mm, e.g. about 1.5 mm.
  • the shape of the hard layer portions 402’ may be geometrically similar to the shape of the distal end surfaces of the burls 20, and for example be circular in plan.
  • the hard layer portions 402’ can also be formed in other shapes if desired.
  • the hard layer 402 preferably has a thickness ti (in a direction perpendicular to the main body surface 22) from 0.1 pm to 10 pm.
  • the hard layer may be disposed on at least some of the burls in a pattern, for example, the hard layer may be disposed on every second or third burl.
  • the hard layer may be made from at least one material selected from the group consisting of: CrN, TiN, aluminium oxides, diamond, diamond-like carbon, doped diamond-like carbon, cubic boron nitride, silicon carbide or chromium nitride, alloys containing one or more of Ti, W and Mo, or combinations thereof.
  • an adhesive layer may be disposed between the insulation layer 401 and the hard layer 402.
  • the insulation layer 401 can be configured such that the minimum resistance ri between any two burls of interest is at least a given value, for example 100 MW. Resistance ri between any two burls may be measurable at the hard layer portions 402’ disposed on the burls. The resistance ri may be configured by choosing an appropriate thickness of the insulation layer 401. The thickness of the insulation layer 401 may be at least 2 nm and or no more than 10 nm.
  • the resistance ri may be configured by selecting some other geometrical property of the insulation layer 401, such as the total surface area over which the insulation layer is disposed on the burls 20, the sides of the burls and or the main body surface 22, varying the thickness of the insulation layer at different locations, or varying the surface properties of the insulation layer.
  • the resistance ri may be so configured, such that flow of charge between the burls is reduced, and consequently the rate and/or severity of oxidation of the substrate holder 60 located at that burl is also reduced.
  • the insulation layer 401 can also be configured such that the capacitance ci between any two burls of interest is less than a given value, for example, 10 nF.
  • the capacitance ci between two burls may be measurable at the hard layer portions 402’ disposed on the burls.
  • the capacitance ci may be selected by varying the thickness of the insulation layer 401 at the distal end of said burl.
  • the capacitance ci may be selected by using a particular material for the insulation layer 401.
  • a group of burls may be configured to have the same maximum capacitance ci between them, and/or configured to have the same maximum capacitance ci between each of the hard layer portions of the burls and the main body 21.
  • a group of burls may be configured to have different maximum capacitances between them.
  • a combination of the capacitance ci and resistance n may be selected for the substrate holder 60 in order to select a particular time constant for the rate of charge transfer across the substrate holder.
  • the resistance u and the capacitance ci may be measurable at the hard layer portions 402’ disposed on the burls.
  • the resistance u and the capacitance ci may be selected to yield a particular RC time constant.
  • the RC value will accordingly determine at what rate the electrical potential at the distal ends of the burls change due to an uncontrolled surface charge on the substrate W, when it is placed into contact with these burls. Accordingly, the RC value can be chosen so as to minimize oxidation of the substrate holder.
  • FIG. 5 shows a second configuration of the substrate holder 60 according to an embodiment of the invention.
  • Substrate holder 60 comprises a main body 21 with a main body surface 22, a plurality of burls 20 projecting from the main body surface 22, an insulation layer 401 and a hard layer 402 defining a plurality of hard layer portions 402’ .
  • the main body 21 of the substrate holder 60 may be made of an electrically insulating material.
  • the insulation layer 401 is disposed on the main body surface 22.
  • the insulation layer may not be disposed on the plurality of burls 20, including not disposed on the sides of said burls.
  • the insulation layer may be of a uniform thickness.
  • the insulation layer may be made from at least one material selected from the group consisting of: SiC, SiSiC, silicon oxides, silicon nitrides, silicon carbides or an aluminium oxide or combinations thereof.
  • An adhesive layer may be disposed between the insulation layer 401 and the main body surface 22.
  • the hard layer 402 is disposed on the main body surface 22, on the burls 20.
  • the hard layer 402 is localized to the distal ends of a group of the burls.
  • the hard layer 402 may accordingly comprise of a plurality of materially-separated hard layer portions 402’ .
  • Each of the hard layer portions 402’ may have a diameter less than that of the distal ends of the underlying burls 20, substantially equal to the diameter of the distal ends of the underlying burls, or greater than the diameter of the distal ends of the underlying burls.
  • Each of the hard layer portions 402’ may comprise a lip overhanging the distal end of the burls, and covering some portion of the side of the burls, or all of the side of the burls.
  • the distance between the centers of two adjacent hard layer portions 402’ may be equal to the pitch of the burls, and for example be about 0.5 mm to 3 mm, e.g. about 1.5 mm.
  • the shape of the hard layer portions 402’ may be geometrically similar to the shape of the distal end surfaces of the burls 20, and for example be circular in plan.
  • the hard layer portions 402’ can also be formed in other shapes if desired.
  • the hard layer 402 preferably has a thickness ti (in a direction perpendicular to the main body surface 22) from 0.1 pm to 10 pm.
  • the hard layer may be disposed on at least some of the burls in a pattern, for example, the hard layer may be disposed on every second or third burl.
  • the hard layer may be made from at least one material selected from the group consisting of: CrN, TiN aluminium oxides, diamond, diamond-like carbon, doped diamond-like carbon, cubic boron nitride, silicon carbide or chromium nitride, alloys containing one or more of Ti, W and Mo, or combinations thereof.
  • an adhesive layer may be disposed between the burls 20 of the main body 21 and the hard layer 402.
  • the insulation layer can therefore be configured such that the minimum resistance ri between any two burls of interest is at least a given value, for example 100 MW. Resistance ri between any two burls may be measurable at the hard layer portions 402’ disposed on the burls.
  • the resistance ri may be configured by choosing an appropriate thickness of the insulation layer.
  • the resistance ri may be configured by selecting some other geometrical property of the insulation layer, such as the total surface area over which the insulation layer is disposed on the main body surface 22, varying the thickness of the insulation layer at different locations, or varying the surface properties of the insulation layer.
  • the resistance ri may be configured by selecting the material forming the main body 21 or the burls 20.
  • the resistance ri may also be configured by selecting some other geometrical property of the main body 21, the main body surface 22 and/or the burls 20, such as the dimensions, pitch or shape of the burls.
  • the resistance ri may be so configured, such that flow of charge between the burls is reduced, and consequently the rate and or severity of oxidation of the substrate holder 60 located at that burl is also reduced.
  • lithographic apparatus in the manufacture of ICs
  • the lithographic apparatus described herein may have other applications, such as the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat-panel displays, liquid-crystal displays (LCDs), thin film magnetic heads, etc.
  • LCDs liquid-crystal displays
  • any use of the terms“wafer” or“die” herein may be considered as synonymous with the more general terms“substrate” or“target portion”, respectively.
  • the substrate referred to herein may be processed, before or after exposure, in for example a track (a tool that typically applies a layer of resist to a substrate and develops the exposed resist), a metrology tool and/or an inspection tool. Where applicable, the disclosure herein may be applied to such and other substrate processing tools. Further, the substrate may be processed more than once, for example in order to create a multi-layer IC, so that the term substrate used herein may also refer to a substrate that already contains one or multiple processed layers.

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  • General Physics & Mathematics (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Public Health (AREA)
  • Environmental & Geological Engineering (AREA)
  • Epidemiology (AREA)
  • Health & Medical Sciences (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
  • Container, Conveyance, Adherence, Positioning, Of Wafer (AREA)

Abstract

L'invention concerne un support de substrat (60) comprenant : un corps principal (21) constitué d'un matériau conducteur dont font saillie une pluralité de protubérances (20) ; une couche d'isolation (401) disposée sur au moins les extrémités distales d'un groupe de ces protubérances ; et une couche dure (402) résistante à l'usure, disposée sur la couche d'isolation. L'invention concerne également un support de substrat comprenant un corps principal constitué d'un matériau isolant dont font saillie une pluralité de protubérances ; une couche dure résistante à l'usure, localisée et disposée sur les extrémités distales d'un groupe de ces protubérances. L'invention concerne encore un appareil lithographique comprenant un de ces supports de substrat.
PCT/EP2020/058474 2019-04-25 2020-03-26 Support de substrat destiné à être utilisé dans un appareil lithographique WO2020216571A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP19171202.5 2019-04-25
EP19171202 2019-04-25

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WO2020216571A1 true WO2020216571A1 (fr) 2020-10-29

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210104428A1 (en) * 2019-10-02 2021-04-08 Canon Kabushiki Kaisha Wafer chuck, method for producing the same, and exposure apparatus

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1359466A1 (fr) * 2002-05-01 2003-11-05 ASML Netherlands B.V. Support, appareil de projection lithographique, méthode de fabrication d'un support et méthode de fabrication d'un dispositif
EP2490073A1 (fr) * 2011-02-18 2012-08-22 ASML Netherlands BV Porte-substrat, appareil lithographique et procédé de fabrication d'un porte-substrat
WO2014114395A1 (fr) * 2013-01-22 2014-07-31 Asml Netherlands B.V. Pince électrostatique
EP2875404A1 (fr) * 2012-07-17 2015-05-27 ASML Netherlands B.V. Pince électrostatique, appareil lithographique et procédé
EP2927947A1 (fr) * 2012-11-28 2015-10-07 Kyocera Corporation Elément de placement et procédé pour fabriquer celui-ci
WO2018007498A1 (fr) * 2016-07-06 2018-01-11 Stichting Nederlandse Wetenschappelijk Onderzoek Instituten Support de substrat et procédé de fabrication de support de substrat

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1359466A1 (fr) * 2002-05-01 2003-11-05 ASML Netherlands B.V. Support, appareil de projection lithographique, méthode de fabrication d'un support et méthode de fabrication d'un dispositif
EP2490073A1 (fr) * 2011-02-18 2012-08-22 ASML Netherlands BV Porte-substrat, appareil lithographique et procédé de fabrication d'un porte-substrat
EP2875404A1 (fr) * 2012-07-17 2015-05-27 ASML Netherlands B.V. Pince électrostatique, appareil lithographique et procédé
EP2927947A1 (fr) * 2012-11-28 2015-10-07 Kyocera Corporation Elément de placement et procédé pour fabriquer celui-ci
WO2014114395A1 (fr) * 2013-01-22 2014-07-31 Asml Netherlands B.V. Pince électrostatique
WO2018007498A1 (fr) * 2016-07-06 2018-01-11 Stichting Nederlandse Wetenschappelijk Onderzoek Instituten Support de substrat et procédé de fabrication de support de substrat

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210104428A1 (en) * 2019-10-02 2021-04-08 Canon Kabushiki Kaisha Wafer chuck, method for producing the same, and exposure apparatus
US11842918B2 (en) * 2019-10-02 2023-12-12 Canon Kabushiki Kaisha Wafer chuck, method for producing the same, and exposure apparatus

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