NL2025509A

NL2025509A - Method for device fabrication

Info

Publication number: NL2025509A
Application number: NL2025509A
Authority: NL
Inventors: Lin Qinghuang; Rispens Gijsbert
Original assignee: Asml Netherlands Bv
Priority date: 2020-05-05
Filing date: 2020-05-05
Publication date: 2020-05-20

Abstract

The present invention relates to improved methods for fabricating devices, for example integrated circuits, using high-sensitivity extreme ultraviolet (EUV) resist. The present invention also relates to an integrated wafer processing system for carrying out such a method. 5 The method comprises fabricating a device, the method comprising; a. exposing an extreme ultraviolet (EUV) resist wafer to EUV radiation to produce an exposed EUV resist wafer; b. baking the exposed EUV resist wafer in an oxygen-rich atmosphere at a temperature in the range of from about 20 °C to about 450 °C; 10 c. processing the exposed EUV resist wafer to produce a device; wherein the oxygen-rich atmosphere comprises oxygen in amount greater than about 21.0% by volume, and wherein the EUV resist comprises one or more of Sn, Sb, Cd, Cr, Zn, Hf, Po, Pd and Te.

Description

METHOD FOR DEVICE FABRICATION

Field

[0001] The present invention relates to methods for fabricating devices, for example integrated circuits. The present invention also relates to an integrated wafer processing system for fabricating devices. The present invention has particular use in connection with fabricating devices using extreme ultraviolet (EUV) lithographic apparatus.

Background to the invention

[0002] 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 devices, for example integrated circuits (ICs). A lithographic apparatus may, for example, project a pattern from a patterning device (e.g., a mask) onto a layer of radiation-sensitive material (resist) provided on a substrate.

[0003] The wavelength of radiation used by a lithographic apparatus to project a pattern onto a substrate determines the minimum size of features that can be formed on that substrate. A lithographic apparatus that uses EUV radiation, that is electromagnetic radiation having a wavelength within the range 4-20 nm, may be used to form smaller features on a substrate than a lithographic apparatus using deep ultraviolet (DUV) radiation (for example with a wavelength of 193 nm).

[0004] As the size of features to be formed in a lithographic process reduces, the performance requirements on all aspects of the lithographic apparatus and materials become stricter.

[0005] The most commonly used resist material for modern integrated circuit fabrication is chemically amplified resist (CAR). However, chemically amplified resist materials suffer from insurmountable issues relating to the established problem of sensitivity-resolution-line edge roughness or stochastic effect trade-off when used for EUV lithography. This trade-off limits the capacity for further improvement in lithographic methods using CAR.

[0006] Non-chemically amplified resists (non-CARs), such as spin-on metal oxide resists, tend to suffer from a high defect density. However, they show promise in that they exhibit high resolution and relatively higher sensitivity for EUV lithography than CAR.

[0007] In view of the above, there remains a need to develop improved methods of fabricating devices, for example integrated circuits, and in particular improved methods of EUV lithography using high-sensitivity EUV resist which exhibits high EUV photon absorption and more efficient solubility switching. There is also a need for an integrated wafer processing system to carry out such methods.

Summary of the invention

[0008] The present invention relates to a method for fabricating a device, the method comprising;

a. exposing an extreme ultraviolet (EUV) resist wafer to EUV radiation to produce an exposed EUV resist wafer;

b. baking the exposed EUV resist wafer in an oxygen-rich atmosphere at a temperature in the range of from about 20 °C to about 450 °C;

c. processing the exposed EUV resist wafer to produce a device;

wherein the oxygen-rich atmosphere comprises oxygen in amount greater than about 21.0% by volume , and wherein the EUV resist comprises one or more of Sn, Sb, Cd, Cr, Zn, Hf, Po, Pd and Te. [0009] The present invention also relates to tin integrated wafer processing system for processing an EUV resist wafer comprising an EUV lithographic apparatus and a processing device comprising an illumination system, a heating element, an oxygen inlet, an oxygen-control mechanism and a vacuum mechanism.

[0010] Such methods and systems allow high resolution lithography with a non-chemically amplified resist platform, resulting in advantageous increases in the efficiency of solubility switching following exposure ofthe wafer to EUV radiation, reduced resist blur and lower stochastic defects.

Brief description of the drawings

[0011] Figure lisa schematic illustration of a lithographic system comprising a lithographic apparatus and a radiation source.

[0012] Figure 2 depicts a schematic overview of a lithographic cell.

[0013] Figure 3 is a diagram showing an embodiment of the integrated wafer processing system of the present invention.

[0014] Figure 4 shows the improvement in resist sensitivity resulting from the method ofthe present invention as the average number of ligands per metal core increases.

Detailed description of the invention

[0015] Figure 1 is a schematic illustration of a lithographic system. The lithographic system comprises a radiation source SO and a lithographic apparatus LA. The radiation source SO is configured to generate an extreme ultraviolet (EUV) radiation beam B. The lithographic apparatus LA comprises an illumination system IL, a support structure MT configured to support a patterning device MA, a projection system PS and a substrate table WT configured to support a substrate W. The illumination system IL is configured to condition the radiation beam B before it is incident upon the patterning device MA. The projection system is configured to project the radiation beam B (now patterned by the patterning device MA) onto the substrate W. The substrate W may include previously formed patterns. Where this is the case, the lithographic apparatus aligns the patterned radiation beam B with a pattern previously formed on the substrate W.

[0016] The radiation source SO, illumination system IL, and projection system PS may all be constructed and arranged such that they can be isolated from the external environment. A gas at a pressure below atmospheric pressure (e.g. hydrogen) may be provided in the radiation source SO. A vacuum may be provided in the illumination system IL and/or the projection system PS. A small amount of gas (e.g. hydrogen) at a pressure well below atmospheric pressure may be provided in the illumination system IL and/or the projection system PS.

[0017] The radiation source SO shown in Figure 1 is of a type that may be referred to as a laser produced plasma (LPP) source. A laser 1, which may for example be a CO2 laser, is arranged to deposit energy via a laser beam 2 into a fuel, such as tin (Sn) that is provided from a fuel emitter 3. Although tin is referred to in the following description, any suitable fuel may be used. The fuel may for example be in liquid form, and may for example be a metal or alloy. The fuel emitter 3 may comprise a nozzle configured to direct tin, for example, in the form of droplets, along a trajectory towards a plasma formation region 4. The laser beam 2 is incident upon the tin at the plasma formation region 4. The deposition of laser energy into the tin creates a plasma 7 at the plasma formation region 4. Radiation, including EUV radiation, is emitted from the plasma 7 during deexcitation and recombination of ions of the plasma.

[0018] The EUV radiation is collected and focused by a near normal incidence radiation collector 5 (sometimes referred to more generally as a normal incidence radiation collector). The collector 5 may have a multilayer structure that is arranged to reflect EUV radiation (e.g. EUV radiation having a desired wavelength such as 13.5 nm). The collector 5 may have an elliptical configuration, having two ellipse focal points. A first focal point may be at the plasma formation region 4, and a second focal point may be at an intermediate focus 6, as discussed below.

[0019] In other embodiments of a laser produced plasma (LPP) source the collector 5 may be a socalled grazing incidence collector that is configured to receive EUV radiation at grazing incidence angles and focus the EUV radiation at an intermediate focus. A grazing incidence collector may, for example, be a nested collector, comprising a plurality of grazing incidence reflectors. The grazing incidence reflectors may be disposed axially symmetrically around an optical axis O.

[0020] The radiation source SO may include one or more contamination traps (not shown). For example, a contamination trap may be located between the plasma formation region 4 and the radiation collector 5. The contamination trap may for example be a rotating foil trap, or may be any other suitable form of contamination trap.

[0021] The laser 1 may be separated from the radiation source SO. Where this is the case, the laser beam 2 may be passed from the laser 1 to the radiation source SO with the aid of a beam delivery system (not shown) comprising, for example, suitable directing mirrors and/or a beam expander, and/or other optics. The laser I and the radiation source SO may together be considered to be a radiation system.

[0022] Radiation that is reflected by the collector 5 forms a radiation beam B. The radiation beam B is focused at point 6 to form an image of the plasma formation region 4, which acts as a virtual radiation source for the illumination system IL. The point 6 at which the radiation beam B is focused may be referred to as the intermediate focus. The radiation source SO is arranged such that the intermediate focus 6 is located at or near to an opening 8 in an enclosing structure 9 of the radiation source.

[0023] The radiation beam B passes from the radiation source SO into the illumination system IL, which is configured to condition the radiation beam. The illumination system IL may include a facetted field mirror device 10 and a facetted pupil mirror device 11. The facetted field mirror device 10 and facetted pupil mirror device 11 together provide the radiation beam B with a desired crosssectional shape and a desired angular distribution. The radiation beam B passes from the illumination system IL and is incident upon the patterning device MA held by the support structure MT. The patterning device MA (which may for example be a mask) reflects and patterns the radiation beam B. The illumination system IL may include other mirrors or devices in addition to or instead of the facetted field mirror device 10 and facetted pupil minor device 11.

[0024] Following reflection from the patterning device MA the patterned radiation beam B enters the projection system PS. The projection system comprises a plurality of mirrors 13,14 that are configured to project the radiation beam B onto a substrate W held by the substrate table WT. The mirrors 13, 14 which form the projection system may be configured as reflective lens elements. The projection system PS may apply a reduction factor to the radiation beam, forming an image with features that are smaller than corresponding features on the patterning device MA. A reduction factor of 4 may for example be applied. Although the projection system PS has two mirrors 13, 14 in Figure 1, the projection system may include any number of mirrors (e.g. six mirrors).

[0025] The lithographic apparatus may, for example, be used in a scan mode, wherein the support structure (e.g. mask table) MT and the substrate table WT are scanned synchronously while a pattern imparted to the radiation beam is projected onto a substrate W (i.e. a dynamic exposure). The velocity and direction of the substrate table WT relative to the support structure (e.g. mask table) MT may be determined by the demagnification and image reversal characteristics of the projection system PS. The patterned radiation beam that is incident upon the substrate W may comprise a band of radiation. The band of radiation may be referred to as an exposure slit. During a scanning exposure, the movement of the substrate table WT and the support structure MT may be such that the exposure slit travels over an exposure field of the substrate W.

[0026] The radiation source SO and/or the lithographic apparatus that is shown in Figure 1 may include components that are not illustrated. For example, a spectral filter may be provided in the radiation source SO. The spectral filter may be substantially transmissive for EUV radiation but substantially blocking for other wavelengths of radiation such as infrared radiation.

[0027] In other embodiments of a lithographic system the radiation source SO may take other forms. For example, in alternative embodiments the radiation source SO may comprise one or more free electron lasers. The one or more free electron lasers may be configured to emit EUV radiation that may be provided to one or more lithographic apparatuses.

[0028] As shown in Figure 2 the lithographic apparatus LA may form part of a lithographic cell EC, also sometimes referred to as a lithocell or (litho)cluster, which often also includes apparatus to perform pre- and post-exposure processes on a substrate W. Conventionally these include spin coaters SC to deposit resist layers, developers DE to develop exposed resist, chill plates CH and bake plates BK, e.g. for conditioning the temperature of substrates W e.g. for conditioning solvents in the resist layers. A substrate handler, or robot, RO picks up substrates W from input/output ports I/O 1,1/O2, moves them between the different process apparatus and delivers the substrates W to the loading bay LB of the lithographic apparatus LA. The devices in the lithocell, which are often also collectively referred to as the track, are typically under the control of a track control unit TCU that in itself may be controlled by a supervisory control system SCS, which may also control the lithographic apparatus LA, e.g. via lithography control unit LACU.

[0029] The present invention arises from the surprising finding that it is possible to provide methods of highly sensitive EUV lithography for device fabrication by baking an exposed EUV resist wafer in an oxygen-rich atmosphere at an elevated temperature. The post-exposure bake in an oxygen-rich atmosphere enhances the sensitivity of the EUV resist, and allows for a faster throughput during EUV lithography.

[0030] The wafer can be made of any semiconducting material known in the art that may be used to produce wafers. For example, the wafer may be a silicon wafer, a silicon carbide wafer, a gallium nitride wafer or a gallium arsenide wafer. Preferably, the wafer is a silicon or silicon carbide wafer. [0031] The metal oxide EUV resist comprises core-shell type nanoparticles, wherein the core is an EUV-absorbing metallic core (typically around 1 nm in diameter) and an organic shell comprising one or more types of ligands. The core and the shell are linked by chemical bonds which are susceptible to cleavage by EUV radiation.

[0032] The metal oxide EUV resist comprises one or more metals that are able to absorb EUV radiation, resulting in ligand cleavage. Preferably, the metal oxide EUV resist contains one or more metals selected from Sn, Sb, Cd, Cr, Zn, Hf, Po, Pd, Te and the like. Preferably, the EUV resist contains Sn, Zr, Hf and combinations thereof.

[0033] The metal oxide EUV resist comprises one or more types of ligands that are able to form a bond, for example, a coordinate bond, to the central metal core. Examples of suitable ligands are amino, aliphatic, aromatic, acrylic, linear- or cyclic- hydrocarbon ligands and the like that are susceptible to cleavage by EUV radiation. Preferably, the ligands are selected from one or more of amino, aliphatic, acrylic, linear- or cyclic- hydrocarbon ligands.

[0034] The metal oxide EUV resist can be deposited on a wafer comprising an organic underlayer (for example an aromatic hydrocarbon underlayer well known to those skilled in the art) to form an EUV resist wafer by any method known in the art, and preferably by a dry or wet method.

[0035] Exposure of the EUV resist wafer to EUV radiation activates the otherwise inert core-shell type nanoparticles by breaking chemical bonds between the metal core (M) and the organic ligands comprising the organic shell. Thus, on exposure of the EUV resist wafer to EUV radiation, one or more types of ligands are cleaved from the metal core of the nanoparticles.

[0036] A mask is used to expose only specific regions of the EUV resist wafer to EUV radiation, allowing cleavage of ligands only in specific regions of the EUV resist wafer.

[0037] After exposure to EUV radiation, the exposed EUV resist wafer is baked in an oxygen-rich environment at an elevated temperature. In the present disclosure, this is referred to as the postexposure bake. The post-exposure bake activates the ligands for the subsequent cross-linking reaction, facilitating a solubility switch.

[0038] The post-exposure bake in an oxygen-rich environment forms cross-linkable functional groups. These cross-linkable functional groups are formed as ligands around the metal centres of the nanoparticles of the metal oxide EUV resist. Preferably the cross-linkable functional-groups comprise one or more of -OH, -COOH, -SH and -CHO.

[0039] The cross-linkable functional groups can undergo a condensation reaction with crosslinkable functional groups on neighbouring metal nanoparticles to form a network of cross-linked nanoparticles. Once a sufficient number of cross-links have been formed (at a critical point P_c), the network of cross-linked nanoparticles becomes insoluble in a given solvent i.e. a solubility switch is said to have occurred.

[0040] Therefore, the section of the EUV resist wafer that was exposed to EUV light is rendered insoluble in a developer.

[0041] During the post-exposure bake, the oxygen-rich environment has an oxygen content higher than that of air, or artificial air as used in a cleanroom. Preferably, the oxygen-rich environment comprises greater than about 21% by volume oxygen, preferably greater than about 23% by volume oxygen, preferably greater than about 25% by volume oxygen, preferably greater than about 30% by volume oxygen, preferably greater than about 40% by volume oxygen and preferably greater than about 50% by volume oxygen.

[0042] The EUV resist wafer is baked at a temperature in the range of from about room temperature to about 450 °C. The baking temperature is preferably greater than about 25 °C, preferably greater than about 30 °C, preferably greater than about 35 °C, preferably greater than about 40 °C, preferably greater than about 45 °C, preferably greater than about 50 °C, preferably greater than about 55 °C, preferably greater than about 60 °C, preferably greater than about 65 °C, preferably greater than about 70 °C, preferably greater than about 75 °C and most preferably greater than about 80 °C. The baking temperature is preferably no more than about 425 °C, preferably no more than about 400 °C, preferably no more than about 375 °C, preferably no more than about 350 °C, preferably no more than about 325 °C, preferably no more than about 300 °C, preferably no more than about 275 °C, preferably no more than about 250 °C, preferably no more than about 225 °C and most preferably no more than about 200 °C.

[0043] In a preferred aspect, the EUV resist wafer is baked at a temperature in the range of from about 80 °C to about 200 °C.

[0044] The EUV resist wafer is baked for a time in the range of from about 10 seconds to about 10 minutes. The baking time is preferably greater than about, 15 seconds, preferably greater than about 20 seconds, preferably greater than about 25 seconds and most preferably greater than about 30 seconds. The baking time is preferably no more than about 8 minutes, preferably no more than about 6 minutes, preferably no more than about 4 minutes and most preferably no more than about 2 minutes.

[0045] In a preferred aspect, the EUV resist wafer is baked for a time in the range of from about 30 seconds to about 2 minutes.

[0046] In a preferred aspect, the EUV resist wafer is baked in an atmosphere comprising greater than about 21 % by volume oxygen, at a temperature of from about 80 °C to about 200 °C and for a time of from about 30 seconds to about 2 minutes. These conditions enable a high proportion of ligands to be activated prior to the cross-linking step, achieving both high EUV resist sensitivity and high throughput.

[0047] Preferably, one or more simple molecular compounds is formed as a by-product of the condensation reaction that occurs during the post-exposure bake. Preferably, the simple molecular compound comprises one or more compounds selected from H2O, NH3, CH4, HC1 and/or CHsCOOH. Most preferably, the one or more simple molecular compound comprises FLO.

[0048] Preferably, the byproduct of the condensation cross-linking reaction is removed from the baking chamber during the post-exposure bake to drive more efficient cross-linking and high EUV lithography throughput. Preferably, removing the simple molecular compound is by the use of a vacuum, for example by establishing a partial vacuum in the baking chamber through the use of vacuum pump.

[0049] Removing the simple molecular compound from the baiting chamber during the postexposure bake drives the cross-linking reaction towards completion i.e. it promotes more efficient cross-linking. This decreases the time required during the post-exposure bake to achieve a solubility switch, allowing for a higher throughput during the production of the device.

[0050] Following the post-exposure bake, the EUV resist wafer can be treated with a wet developer or a dry etch method to retain the exposed resist, allowing a circuit pattern to be formed on the organic underlayer of the wafer.

[0051] The wafer can be further processed by any method known in the art to fabricate a device, for example an integrated circuit.

[0052] As shown in Figure 3, the present invention is also concerned with providing tin integrated wafer processing system (100) for performing the method of the present invention. Preferably, the integrated wafer processing system comprises an EUV lithographic apparatus (101) and a processing device (102) comprising a heating element (103), an oxygen inlet (104), an oxygen-control mechanism (105) and a vacuum mechanism (106).

[0053] The vacuum mechanism is configured to remove one or more simple molecular compounds formed as a by-product of the condensation reaction that occurs during the post-exposure bake.

[0054] The oxygen-control mechanism is configured to maintain an oxygen level of the atmosphere of an internal chamber of the processing device at an oxygen level higher than that of air. or artificial air as used in a cleanroom. Preferably, the oxygen-control mechanism maintains the atmosphere at greater than about 21% by volume oxygen, preferably greater than about 23% by volume oxygen, preferably greater than about 26% by volume oxygen, preferably greater than about 30% by volume oxygen, preferably greater than about 40% by volume oxygen and preferably greater than about 50% by volume oxygen.

[0055] Tire heating element is configured to maintain an internal chamber of the processing device at a temperature in the range of from about room temperature to about 450 °C. The heating element is preferably configured to maintain the temperature of the chamber at greater than about 25 °C, preferably greater than about 30 °C, preferably greater than about 35 °C, preferably greater than about 40 °C, preferably greater than about 45 °C, preferably greater than about 50 °C, preferably greater than about 55 °C, preferably greater than about 60 °C, preferably greater than about 65 °C, preferably greater than about 70 °C, preferably greater than about 75 °C and most preferably greater than about 80 °C. The heating element is preferably configured to maintain the temperature of the chamber at no more than about 425 °C, preferably no more than about 400 °C, preferably no more than about 375 °C, preferably no more than about 350 °C, preferably no more than about 325 °C, preferably no more than about 300 °C, preferably no more than about 275 °C, preferably no more than about 250 °C, preferably no more than about 225 °C and most preferably no more than about 200 °C.

[0056] In a preferred aspect, the heating element is configured to maintain an internal chamber of the processing device at a temperature in the range of from about 80 °C to about 200 °C.

[0057] In a preferred aspect, the oxygen-control mechanism is configured to maintain an oxygen level of the atmosphere of an internal chamber of the processing device at greater than about 40% by volume oxygen, and the heating element is configured to maintain the internal chamber at a temperature in the range of from about 80 °C to about 200 °C.

[0058] The dose to print of metal oxide EUV resist is given by:

Dp —--xs_c where D_P - dose to print (mJ/cm²) a - absorption coefficient (1/cm)

Sc = chemical sensitivity (cm³/mJ) - the volume of resist that is cleared for a positive-tone resist or retained for a negative-tone resist by one EUV photon

[0059] The chemical sensitivity of an EUV resist without the post-exposure bake under an elevated oxygen atmosphere of the present invention is given by:

ίθ = n_ov_o where n₍₁ = the number of cross-linked metal oxide nanoparticles without the post-exposure bake under an elevated oxygen atmosphere

Vo = the unit volume of metal oxide resist that is retained as a negative tone resist by one EUV photon

[0060] The chemical sensitivity of an EUV resist following the post-exposure bake under an elevated oxygen atmosphere of the present invention is given by:

S_c = nv₀ =βη_ον_ο where n = the number of cross-linked metal oxide nanoparticles with the post-exposure bake under an elevated oxygen atmosphere β = the solubility switch accelerator factor resulting from the post-exposure bake under an elevated oxygen atmosphere due to the increase in the number of activated cross-linkable ligand sites.

[0061] To calculate the critical fraction of units to form a gel i.e. the point at which the system becomes insoluble;

_ 1 _ 1 ^c z — 1 m-1 where P_c = the critical fraction of units to form a gel upon which the system becomes insoluble

Z - the number of cross-linkable bonds per unit and Z = m, where m is the number of ligands per metal core of the metal oxide resist

[0062] Therefore β x — = z — 1 = m — 1

P ^rc

[0063] Overall, the chemical sensitivity of the system following the post-exposure bake under an elevated oxygen atmosphere is given by:

S_c = βη_ον_ο = (m- l)n_ov_o where m = the number of ligands per core of metal oxide resist, and m > 2

[0064] The overall EUV resist sensitivity improvement (%) as a result of the post-exposure bake under an elevated oxygen atmosphere is:

Dp — Dp m — 2

EUV resist sensitivity improvement (%) = —— =----[0065] As shown in Figure 4, a substantial improvement in resist sensitivity can be achieved by applying the method of the present invention, compared to the use of an equivalent EUV resist without the post-exposure bake in an atmosphere with an elevated oxygen level. The improvement of the present invention is particularly substantial at higher average numbers of ligands per metal core in the resist.

[0066] The term EUV radiation may be considered to encompass electromagnetic radiation having a wavelength within the range of 4-20 nm, for example within the range of 13-14 nm. EUV radiation may have a wavelength of less than 10 nm, for example within the range of 4-10 nm such as 6.7 nmoró.S nm.

[0067] The term “resist” refers to a light-sensitive film which is coated on top of a wafer and allows a pattern to transferred onto the wafer during semiconductor fabrication.

[0068] The term “ligand” may be considered to encompass an ion or molecule which is able to form a bond, for example a coordinate bond, to a central metal core.

[0069] The term “condensation reaction” may be considered to encompass a chemical reaction in which two species combine to form a larger species, producing a small molecule as a by-product. [0070] The term “baking” may be considered to encompass a process comprises subjecting a species to a temperature above ambient temperature.

[0071] The term “sensitivity” refers to the minimum energy that is required to generate a welldefined feature in the photoresist on the substrate, measured in mJ/cm².

[0072] The term “resolution” refers to the smallest feature that can be printed on a substrate.

[0073] The term “line edge roughness” refers to variations in the position of the edge of a resist feature over the length of the feature.

[0074] Although specific reference may be made in this text to the use of lithographic apparatus in the manufacture of ICs, it should be understood that the lithographic apparatus described herein may have other applications. Possible other applications include the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat-panel displays, liquidcrystal displays (LCDs), thin film magnetic heads, etc.

[0075] While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. The descriptions above are intended to be illustrative, not limiting. Thus it will be apparent to one skilled in the art that modifications may be made to the invention as described without departing from the scope of the clauses set out below. Other aspects of the invention are set out as in the following numbered clauses:

1. A method for fabricating a device, the method comprising;

c. processing the exposed EUV resist wafer to produce a device;

wherein the oxygen-rich atmosphere comprises oxygen in amount greater than about 21.0% by volume, and wherein the EUV resist comprises one or more of Sn, Sb, Cd, Cr, Zn, Hf, Po, Pd and Te.

2. The method of clause 1, wherein the EUV resist comprises one or more of Sn, Zr and Hf.

3. The method of clause 1 or clause 2, wherein the method additionally comprises removing one or more by-products during the baking step.

4. The method of clause 3, wherein the one or more by-products comprise one or more compounds selected from TLO, NH.;, CH4, HQ and/or CHsCOOH.

5. The method of any preceding clause, wherein the EUV resist wafer is baked at a temperature in the ranee of from about 80 °C to about 200 °C.

6. The method of any preceding clause, wherein the EUV resist wafer is baked for a time in the range of from about 10 seconds to about 10 minutes

7. The method of any preceding clause, wherein the EUV resist wafer is baked for a time in the range of from about 30 seconds to about 2 minutes.

8. The method of any preceding clause, wherein the EUV resist wafer is baked at a temperature in the range of from about 80 °C to about 200 °C and for a time in the range of from about 30 seconds to about 2 minutes.

9. The method of any preceding clause, wherein the oxygen-rich atmosphere comprises oxygen in an amount greater than about 25.0% by volume.

10. The method of any preceding clause, wherein the oxygen-rich atmosphere comprises oxygen in an amount greater than about 30.0% by volume.

11. The method of any preceding clause, wherein the oxygen-rich atmosphere comprises oxygen in an amount greater than about 40.0% by volume.

12. The method of clause 3 or clause 4, wherein the one or more by-products is removed by vacuum.

13. An integrated wafer processing system for processing an EUV resist wafer comprising an EUV lithographic apparatus and a processing device comprising a heating element, an oxygen inlet, an oxygen-control mechanism and a vacuum mechanism.

14. The integrated wafer processing system of clause 13, wherein the heating element is configured to maintain an internal chamber of the processing device at a temperature in the range of from about 20 °C to about 450 °C.

15. The integrated wafer processing system of clause 13 or clause 14, wherein the oxygen-control mechanism is configured to maintain an oxygen level of the atmosphere of an internal chamber of the processing device of at least 21.0% by volume.

Claims

1. A device arranged for exposing a substrate.