Substrate processing apparatus, substrate processing method, and storage medium

Abstract

The present invention provides a substrate processing apparatus, a substrate processing method, and a storage medium. The substrate processing apparatus (1) includes: a holding section that holds a substrate in a processing container, wherein the substrate has a pattern formed on a surface thereof from a resist material for EUV lithography; a rotation drive section that rotates the holding section; and a light source section having a plurality of light sources that irradiate the surface of the substrate held by the holding section with light containing vacuum ultraviolet light, wherein the holding section is rotated by the rotation drive section at a rotation speed of 0.5 rpm to 3 rpm. The present invention can improve the roughness of the surface in a substrate using a resist material suitable for EUV lithography.

Description

TECHNICAL FIELD

[0001] The present application relates to a substrate processing apparatus, a substrate processing method, and a storage medium. BACKGROUND

[0002] Patent Document 1 describes a technique in which, in a manufacturing process of a semiconductor device, a step of irradiating a front surface of a resist formed on a surface of a substrate, which has been patterned after exposure, with light having a wavelength of 200 nm or less, and a step of etching an underlayer film of the resist film are performed in this order. The step of irradiating the light having a wavelength of 200 nm or less (hereinafter, simply referred to as a step of irradiating light.) aims at, for example, improving the roughness (unevenness) of the resist film.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENT

[0005] Patent Document 1: Japanese Patent No. 3342856 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The present application provides a technique capable of improving the roughness of a surface on a substrate on which a resist material suitable for EUV lithography is used.

[0008] MEANS OF SOLVING THE PROBLEM

[0009] A substrate processing apparatus of one embodiment of the present application includes a holding portion that holds a substrate in a processing container, in which the substrate has a pattern formed on a surface thereof from a resist material for EUV lithography; a rotation drive portion that rotates the holding portion; and a light source portion that has a plurality of light sources and irradiates a surface of the substrate held by the holding portion with light containing vacuum ultraviolet light, in which the holding portion is rotated at a rotation speed of 0.5 rpm to 3 rpm by the rotation drive portion.

[0010] EFFECT OF THE INVENTION

[0011] According to the present application, a technique capable of improving the roughness of a surface on a substrate on which a resist material suitable for EUV lithography is used is provided. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 FIG. 1 is a view that shows a substrate processing apparatus according to one embodiment of the present application.

[0013] Figure 2 FIG. 2 is a view that shows a process performed on a substrate by the substrate processing apparatus.

[0014] Figure 3 FIG. 3 is a view that shows a configuration of light sources in the substrate processing apparatus.

[0015] Figure 4 is a block diagram illustrating the functionality of the controller.

[0016] Figure 5 is a block diagram illustrating the hardware configuration of the controller.

[0017] Figure 6 is a graph illustrating the pressure change during substrate processing in the substrate processing apparatus.

[0018] Figure 7 is a graph illustrating the results of Evaluation Test 1.

[0019] Figure 8 is a graph illustrating the intensity change of the light received by the rotating substrate.

[0020] Figure 9 is a graph illustrating the illuminance distribution in the substrate.

[0021] Figure 10 is a graph illustrating the results of Evaluation Test 2.

[0022] Figure 11 is a graph illustrating the results of Evaluation Test 3.

[0023] Figure 12 is a graph illustrating the results of Evaluation Test 4.

[0024] Explanation of Reference Numerals

[0025] 1... substrate processing apparatus; 13... resist pattern; 20... processing chamber; 21... housing; 22... delivery port; 23... gate valve; 25... rotary support portion; 26... holding portion; 27... rotary drive portion; 30... gas supply portion; 35... gas exhaust portion; 40... light irradiation mechanism; 41... housing; 42... light source; 44... point light source; 100... controller. DETAILED DESCRIPTION

[0026] Hereinafter, various exemplary embodiments will be described.

[0027] In one exemplary embodiment, a substrate processing apparatus includes a holding portion that holds a substrate in a processing vessel, wherein the substrate has a pattern formed on a surface thereof from a resist material for EUV lithography; a rotary drive portion that rotates the holding portion; and a light source portion having a plurality of light sources that irradiate the surface of the substrate held by the holding portion that is rotated by the rotary drive portion with light containing vacuum ultraviolet light, and the rotational speed of the substrate at the time of irradiation with light by the light source portion is 0.5 rpm to 3 rpm.

[0028] In a substrate in which a pattern composed of an EUV lithography resist material is formed on a surface, in a case where vacuum ultraviolet light is irradiated to the pattern, the intrusion of light on the low wavelength side becomes insufficient. In contrast, according to the substrate processing apparatus described above, by setting the rotational speed to the range described above, light on the low wavelength side also becomes easy to intrude into the pattern, and thus the improvement effect on the roughness of the surface can be increased.

[0029] Here, the rotational speed of the substrate during irradiation of light with the light source section can be changed.

[0030] By changing the rotational speed of the substrate during irradiation of light, the composition of light that intrudes into the pattern can be changed. Thus, by adopting a configuration in which the rotational speed is changed while light is irradiated, the composition of light that is suitable for improving the roughness of the surface can be made to intrude into the pattern, and the improvement effect on the roughness of the surface can be further increased.

[0031] Here, the rotational speed of the substrate during irradiation of light with the light source section can be changed.

[0032] As described above, by adopting a configuration in which the rotation is temporarily stopped, the amount of light that is irradiated to the pattern and the like can be adjusted. Thus, the composition of light that is suitable for improving the roughness of the surface can be made to intrude into the pattern, and the improvement effect on the roughness of the surface can be further increased.

[0033] Here, the rotational speed of the substrate during irradiation of light with the light source section can be changed.

[0034] As described above, by changing the pressure in the processing container while supplying and discharging gas during irradiation of light with the light source section, the pressure in the processing container can be made to be in a state that corresponds to the surface condition of the substrate while vacuum ultraviolet light is irradiated to the pattern.

[0035] In one example embodiment, in a substrate processing method, a substrate in which a pattern composed of an EUV lithography resist material is formed on a surface is rotated at a rotational speed of 0.5 rpm to 3 rpm in a processing container, and light containing vacuum ultraviolet light is irradiated to the surface of the substrate from a light source section having a plurality of light sources.

[0036] According to the substrate processing method described above, by setting the rotational speed to the range described above, light on the low wavelength side becomes easy to intrude into the pattern, and thus the improvement effect on the roughness of the surface can be increased.

[0037] In another example embodiment, the storage medium is a computer-readable storage medium having stored thereon a program for causing an apparatus to perform the substrate processing method described above.

[0038] Various example embodiments will be described in detail below with reference to the accompanying drawings. In addition, like or corresponding portions are denoted with like reference numerals in each drawing.

[0039] [Structure of substrate processing apparatus]

[0040] Figure 1 is a schematic view (longitudinal cross-sectional side view) showing a substrate processing apparatus of the present embodiment. Figure 1 The substrate processing apparatus 1 shown irradiates a wafer W (substrate) with light for processing. For example, the substrate processing apparatus 1 is configured to irradiate a resist film or a resist pattern formed on the surface of the wafer W with vacuum ultraviolet light (VUV light) to improve the roughness of the surface of the resist material described above.

[0041] The wafer W is in the shape of a circular plate, but a wafer in the shape of a circular segment or a polygon, or the like, other than a circular shape, can also be used. The wafer W can be, for example, a semiconductor substrate, a glass substrate, a mask substrate, an FPD (Flat Panel Display) substrate, or the like.

[0042] Figure 2 shows an example of processing a wafer W by the substrate processing apparatus 1. As shown in Figure 2 (a), in the wafer W, a resist pattern 13 is formed on a SOC film 11 (Silicon-on-Carbon) as an underlayer film and a SOG film 12 (Silicon-on-Glass) on the SOC film 11. In the substrate processing apparatus 1, by irradiating the surface of such a wafer W with light L1 for processing, the roughness of the surface of the resist pattern 13 is improved as shown in Figure 2 (b). In addition, the resist pattern 13 is a mask pattern for etching the SOC film 11 and the SOG film 12 as underlayer films to form a pattern on the underlayer films described above.

[0043] Returning to Figure 1 , each portion of the substrate processing apparatus 1 will be described. The substrate processing apparatus 1 includes, as shown in Figure 1 , a processing chamber 20, a light irradiation mechanism 40 (light source portion), and a controller 100 (control portion). In addition, in Figure 1 , only a portion of the structure included in the light irradiation mechanism 40 is shown.

[0044] The processing chamber 20 includes a housing (processing container) 21, a transfer port 22, a rotary support portion 25, a gas supply portion 30, and a gas exhaust portion 35. The housing 21 is, for example, a portion of a vacuum container provided in an atmosphere, and is configured to be able to accommodate a wafer W transferred by a transfer mechanism (not shown). That is, the housing 21 functions as a processing container that performs processing of the wafer W inside. In the substrate processing apparatus 1, the wafer W is processed in a state in which the wafer W is accommodated in the housing 21. The transfer port 22 is formed in a side wall of the housing 21. The transfer port 22 is an opening for transferring the wafer W to and from the housing 21. The transfer port 22 is opened and closed by a gate valve 23.

[0045] The rotary support portion 25 has a function of rotating the wafer W while holding the wafer W based on an instruction of the controller 100 inside the housing 21. The rotary support portion 25 has, for example, a holding portion 26 and a rotation drive portion 27. The holding portion 26 supports a central portion of the horizontally disposed wafer W with the surface on which the resist pattern 13 is formed facing upward, and holds the wafer W by, for example, vacuum adsorption or the like. The rotation drive portion 27 has a function of rotating the holding portion 26 holding the wafer W around an axis Al that is perpendicular. The rotation drive portion 27 is, for example, a rotary actuator that is powered by an electric motor.

[0046] The gas supply portion 30 is configured to supply a non-active gas (for example, argon, nitrogen, or the like) into the housing 21 via a through-hole 21a formed in the housing 21. The gas supply portion 30 has a gas source 30a, a valve 30b, and a pipe 30c. The gas source 30a stores the non-active gas, and functions as a supply source of the non-active gas. The valve 30b is operated based on an operation signal from the controller 100, and opens and closes the pipe 30c. The pipe 30c is connected to the gas source 30a, the valve 30b, and the through-hole 21a in this order from an upstream side.

[0047] The gas exhaust portion 35 exhausts the gas from the housing 21 via a through-hole 21b formed in the housing 21. The gas exhaust portion 35 has a vacuum pump 35a and a pipe 35c. The vacuum pump 35a exhausts the gas from the housing 21. The pipe 35c connects the through-hole 21b and the vacuum pump 35a.

[0048] The light irradiation mechanism 40 includes a housing 41, a light source 42, and a switch 43. The housing 41 is provided in an upper portion of the housing 21. The light source 42 has a plurality of light sources accommodated in the housing 41. Figure 3is a plan view showing an example of the arrangement of the light source 42. The light source 42 is arranged in two concentric circles centered on the axis Al that is the rotation axis of the holding portion 26 when viewed from above. Specifically, four light sources 42 are arranged at intervals in the circumferential direction along the inner circle, and eight light sources 42 are arranged at intervals in the circumferential direction along the outer circle. Further, the light source 42 is arranged as described above, and the light is irradiated to the entire surface of the wafer W held by the holding portion 26. Further, the switch 43 switches on and off the lighting of the light source 42. The operation of the switch 43 is controlled by the controller 100. Further, the arrangement example of the light source 42 is only one example, and can be appropriately changed.

[0049] The light source 42 irradiates, for example, light having a wavelength of 115 nm to 400 nm, that is, light having a continuous spectrum of 115 nm to 400 nm. The light having the continuous spectrum of this range can also include light having a wavelength of 10 nm to 200 nm (that is, VUV light), and near ultraviolet light (near ultraviolet rays) having a longer wavelength than the VUV light. The light from the light source 42 can include light having a wavelength of 160 nm or less. The light source 42 is, for example, a deuterium lamp configured to be able to irradiate VUV light having a wavelength of 200 nm or less. The wavelength of the peak of the continuous spectrum can be, for example, 160 nm or less, or 150 nm or more.

[0050] The wavelength band of the spectrum of the light irradiated from the light source 42 is wide, and thus the resist pattern 13 on the wafer W receives the energy of light of various wavelengths. As a result, various reactions occur on the surface of the resist pattern 13. Specifically, various compounds are generated by breaking the chemical bonds at each position in the molecules constituting the resist pattern 13, and thus the orientation of the molecules present in the resist film before light irradiation can be eliminated. As a result, the surface free energy of the resist pattern 13 is reduced, and the internal stress is reduced. That is, by using the light source 42 as the light source, the mobility of the surface of the resist pattern 13 is easily increased, and as a result, the improvement effect of the roughness of the surface can be improved.

[0051] In addition, in the resist pattern 13, a cross-linking reaction also occurs during and after the irradiation of the light from the light source 42, particularly the VUV light. Since the cross-linking reaction occurs simultaneously in the resist pattern 13, the surface of the resist pattern 13 is solidified, and as a result, the etching resistance is increased. Therefore, when etching the lower layer film using this resist pattern 13 as a mask, the roughness of the pattern surface in the lower layer film can be improved.

[0052] The component of light shorter than 160 nm in wavelength among the light radiated from the light source 42 greatly contributes to improvement of the roughness of the pattern surface in the resist pattern 13 and the underlayer film. For example, it is confirmed that in the case where only light longer than 160 nm in wavelength is radiated to the resist pattern, improvement of the roughness of the surface is not sufficiently performed, and only cleavage of the chemical bond is performed. However, in the case where only light shorter than 160 nm in wavelength is radiated, improvement of the roughness of the surface is not sufficiently performed, either. Therefore, light having a continuous spectrum including both light longer than 160 nm in wavelength and light shorter than 160 nm in wavelength, such as a deuterium lamp, is important for improvement of the roughness of the surface.

[0053] In addition, the larger the wavelength of the light from the light source 42 radiated to the resist pattern 13, the deeper the light reaches in the resist pattern 13 in the case where the intensity thereof is larger. However, the wavelength of the peak of the spectrum of the light radiated from the light source 42 is included in the wavelength band of VUV light (10 nm to 200 nm) as described above, and therefore the intensity of light having a relatively large wavelength is small among the light radiated from the light source 42. Therefore, the portion of the light radiated from the light source 42 that reaches the deep layer of the resist film is small, and cleavage of the bond of the molecule described above in the deep layer of the resist film can be suppressed. That is, by using the light source 42, it is possible to limit the region in the resist pattern 13 where a reaction occurs due to light irradiation to the surface.

[0054] The case where the depth of the VUV light region in the resist pattern varies depending on the wavelength is the same for light in the VUV light region. That is, as described above, the component of light having a longer wavelength than light in the vicinity of 150 nm to 160 nm where the intensity of light becomes the largest reaches the deep layer (for example, 150 nm or more) of the resist pattern 13. On the other hand, the component of light shorter than 150 nm reaches only the vicinity of the surface (for example, 50 nm or less) of the resist pattern 13. In addition, the component of light shorter than 150 nm has a small intensity among the VUV light compared to the wavelength band of the peak. That is, the component of light shorter than 160 nm in wavelength, which contributes to improvement of the roughness of the surface, reaches only the vicinity of the surface (does not reach the deep layer) of the resist pattern 13, and promotes curing of the surface of the resist pattern 13 due to crosslinking reaction in the vicinity of the surface. As described above, the component of light shorter than 160 nm in wavelength is important for promoting crosslinking reaction in the vicinity of the surface of the resist pattern 13. As described above, the component of light shorter than 160 nm in wavelength has a large effect on the resist pattern 13, and can promote dissociation of the side chain and the like of the component included in the resist pattern 13, reduction of internal stress, and crosslinking reaction. On the other hand, light longer than 160 nm in wavelength is also required for improving the film quality of the resist pattern 13 as a whole, and therefore by radiating the light described above in an appropriate balance, it is possible to achieve improvement of the film quality.

[0055] The light source 42 generates light of a top hat type having a flat intensity distribution compared to light of a Gaussian distribution. Furthermore, even with light of a top hat type, the intensity distribution is not formed completely flat. That is, light having an irradiation range that exits from the point light source 44 (refer to Figure 1 ) within the light source 42 is irradiated, specifically, to the wafer W, as a conical light path having the point light source 44 as an apex. As described above, the light irradiated from the light source 42 has a circular irradiation range in the irradiation surface. Furthermore, in Figure 3 , the approximate propagation range of the light output from each light source 42 on the wafer W surface is indicated by a dashed line.

[0056] The VUV light reacts with oxygen in an atmosphere in which oxygen is present, so the improvement effect on the roughness of the resist pattern 13 is reduced. Therefore, as described later, in order to remove oxygen within the housing 21 when processing the wafer W, a vacuum atmosphere is formed within the housing 21. Here, as described above, the molecules having a small molecular weight that are generated by the cleavage of bonds by light irradiation are easily released as gas into the vacuum atmosphere, and as described above, cleavage of such bonds does not easily occur in the deep layer of the resist film, so release of gas from the deep layer can be suppressed. Therefore, for the resist pattern 13, changes in height or width, or changes in the shape, etc., can be suppressed.

[0057] Returning to Figure 1 , the controller 100 of the substrate processing apparatus 1 controls the rotary support portion 25, the gas supply portion 30, the gas exhaust portion 35, and the light irradiation mechanism 40. As exemplified in Figure 4 , in the controller 100, as a functional configuration (hereinafter referred to as a "functional module"), there are an irradiation control portion 111, a gas supply control portion 112, an exhaust control portion 113, and an access control portion 114. The above-described functional modules are merely divisions of the functions of the controller 100 into a plurality of modules for convenience, and do not mean that the hardware that constitutes the controller 100 must be divided into such modules.

[0058] The irradiation control portion 111 controls the light irradiation mechanism 40 to irradiate VUV light at a desired timing. For example, the irradiation control portion 111 controls the light irradiation mechanism 40 to turn on all of the light sources 42 before the timing of irradiation. Furthermore, the irradiation control portion 111 controls the light irradiation mechanism 40 to turn off all of the light sources 42 after the timing of irradiation ends.

[0059] The gas supply control portion 112 controls the valve 30b to supply the non-active gas into the housing 21 from the through-hole 21a. The exhaust control portion 113 controls the vacuum pump 35a to exhaust the gas within the housing 21 to the outside through the through-hole 21b.

[0060] The access control section 115 controls the gate valve 23 to open and close the transport port 22 in conjunction with the action of inputting the wafer W into the housing 21 and the action of delivering the wafer W from the housing 21, and controls the rotary support section 25 to switch between the holding and release of the wafer W by the holding section 26.

[0061] The controller 100 is constituted by one or a plurality of control computers. For example, the controller 100 has Figure 5 The circuit 120 has one or a plurality of processors 121, a memory 122, a storage 123, and an input / output port 124. The storage 123 has, for example, a computer-readable storage medium such as a hard disk. The storage medium stores a program for causing the substrate processing apparatus 1 to execute the substrate processing steps described later. The storage medium can be a nonvolatile semiconductor memory, a removable medium such as a magnetic disk and an optical disk. The memory 122 temporarily stores the program loaded from the storage medium of the storage 123 and the operation result of the processor 121. The processor 121 cooperates with the memory 122 to execute the above program, thereby constituting the above functional modules. The input / output port 124 performs input and output of electric signals between the sections controlled by the controller 100 in accordance with the instruction from the processor 121.

[0062] Furthermore, the hardware configuration of the controller 100 is not necessarily limited to constituting the functional modules by the program. For example, the functional modules of the controller 100 can be constituted by a dedicated logic circuit or an ASIC (Application Specific Integrated Circuit) obtained by integrating the same.

[0063] [Substrate processing method]

[0064] Hereinafter, the action (substrate processing method) of the substrate processing apparatus 1 will be described with reference to Figure 1 and Figure 6 . Figure 6 is a graph showing the outline of the change of the pressure in the housing 21 with time. Figure 7 The horizontal axis of the graph of Figure 7 indicates the elapsed time in processing, and the vertical axis indicates the pressure (unit: Pa) in the housing 21 as a processing vessel and is schematically and approximately shown as a logarithmic axis. First, in a state where the actions of the gas supply section 30 and the gas exhaust section 35 are stopped, the wafer W is delivered into the housing 21 by the transport mechanism. When the wafer W is placed on the holding section 26 of the rotary support section 25, the gate valve 23 is closed to make the housing 21 airtight. At this time, the inside of the housing 21 becomes, for example, an atmospheric atmosphere at a standard pressure (time t0 of Figure 7 ). Then, the pressure in the housing 21 is reduced by the action of the gas exhaust section 35.

[0065] The pressure is reduced, and when the pressure in the chamber 21 becomes 1 Pa (at time tl), the state at that time is maintained for a prescribed time. After the pressure is temporarily maintained at 1 Pa (at time t2), the valve 30b of the gas supply portion 30 is opened to supply Ar gas into the chamber 21. Thus, an Ar gas atmosphere is formed in the chamber 21, and the pressure in the chamber 21 rises. Further, the pressure reduction rate and the pressure rise rate can be controlled by the operation of the gas supply portion 30 and the gas exhaust portion 35. In addition, the pressure reduction rate and the pressure rise rate can be constant, or can be changed midway.

[0066] When the pressure in the chamber 21 reaches 10,000 Pa due to the Ar gas, for example, light containing VUV light is irradiated from the light source 42 to the wafer W while the pressure in the chamber 21 is maintained (at time t3). When light is irradiated from the light source 42 for a prescribed time, for example, 30 seconds, the light irradiation is stopped (at time t4). Thereafter, the operation of the gas supply portion 30 and the gas exhaust portion 35 is stopped, and after the pressure in the chamber 21 returns to the atmospheric atmosphere, the wafer W is delivered from the chamber 21. The wafer W processing by the substrate processing apparatus 1 is completed by the above-described manner.

[0067] As described above, in the substrate processing apparatus 1, when light is irradiated from the light source 42 to the wafer W, the operation of supplying gas by the gas supply portion 30 and the operation of exhausting gas by the gas exhaust portion 35 are also performed. Therefore, it can be said that the replacement of Ar gas occurs while the pressure in the chamber 21 is maintained.

[0068] Further, during the period when light is irradiated from the light source 42 (between time t3 and time t4), the pressure in the chamber 21 can be constant, or can gradually change. In Figure 6 In the example shown, the pressure in the chamber 21 is made 10,000 Pa during the period when light is irradiated from the light source 42 in order to suppress the outgassing from the surface of the wafer W. However, the amount of outgassing gradually decreases during the period when light is irradiated from the light source 42. In this case, control can be performed so that the pressure in the chamber 21 gradually decreases. By adopting such a configuration, light can be irradiated to the wafer W in a state closer to vacuum.

[0069] [About the substrate processing with an EUV exposure resist material as the object]

[0070] Here, in the substrate processing apparatus 1 of the present embodiment, the resist material for the resist pattern 13 is a material suitable for EUV lithography using EUV laser light as an exposure light source, and in this case, the following was found. That is, it was found that by irradiating light containing the above-described VUV light under prescribed conditions, the roughness of the surface of the resist pattern 13 can be improved, and the roughness of the surface of a pattern obtained by etching the resist pattern 13 as a mask can also be improved. Furthermore, EUV laser light (Extreme Ultraviolet: EUV) is laser light having a wavelength of 13.5 nm. In the following embodiments, the improvement of the roughness of the surface is described in the case where the resist material can be used for EUV lithography.

[0071] In EUV lithography, high definition, reduction of the roughness of the surface, and high sensitivity are required. In order to satisfy such requirements, the resist material for EUV lithography can be improved. Furthermore, in the following embodiments, a case where a general resist material for EUV lithography is used is described. Furthermore, additives such as an acid generator, a solvent, a decomposition product, and the like can be contained in the resist material.

[0072] As described above, by irradiating light containing VUV light in the substrate processing apparatus 1, the chemical bonds at each position in the molecules constituting the resist pattern 13 are cleaved in the wafer W, and thus various compounds are generated. At this time, since the cleavage of the chemical bonds occurs at each position, the roughness of the surface of the resist pattern 13 is reduced. Furthermore, by the cross-linking reaction occurring during and after the irradiation of the light containing VUV light, the surface of the resist pattern 13 is solidified, and as a result, the etching resistance is increased. That is, by irradiating VUV light, the cleavage of the chemical bonds and the cross-linking reaction in the resist pattern 13 can be appropriately performed. Moreover, by the cleavage of the chemical bonds and the cross-linking reaction, the roughness of the surface of the lower layer film etched using the resist pattern 13 and the resist pattern 13 as a mask can be improved.

[0073] However, in the case where either the cleavage of the chemical bonds or the cross-linking reaction in the resist pattern 13 is insufficient or excessive, the improvement effect of the roughness of the surface described above is reduced. In other words, by appropriately adjusting the irradiation level of the light containing VUV light irradiated in the substrate processing apparatus 1, the improvement effect of the roughness of the surface can be increased. In this regard, the results of the verification are described below. In particular, the resin material used in the resist for EUV lithography has low responsiveness to the light from the light source 42 containing VUV light, and thus various additives are used to control the characteristics thereof. Therefore, depending on how the additives contained in the resist material react to the light from the light source 42 and the like, the improvement effect of the roughness of the surface changes. This is described below.

[0074] As the elements of the irradiation conditions which are changed in the case of irradiating the VUV light to the resist pattern 13 in the substrate processing apparatus 1, there are "irradiation amount (cumulative irradiation amount)", "Ar flow rate at the time of irradiation", "rotation speed of the wafer at the time of irradiation", and "current compensation value (bias) of the light source". Among them, the "irradiation amount" corresponds to the total amount of the energy of the light (VUV light) emitted from the light source 42 to the resist pattern 13. Further, the "Ar flow rate at the time of irradiation" and the "current compensation value of the light source" are related to the transmissivity of the light emitted from the light source 42. That is, they affect how far the VUV light can reach in the resist pattern 13. Further, the "rotation speed of the wafer" affects how far the VUV light emitted from the light source 42 can cause modification effect to the resist pattern 13. Hereinafter, the results of the evaluation performed by changing the conditions related to the above elements will be described.

[0075] (Ar flow rate and lamp compensation value)

[0076] In the case of irradiating the light from the light source 42 in the substrate processing apparatus 1 to perform modification of the resist pattern 13, both the Ar flow rate and the lamp compensation value are values related to the transmissivity of the light emitted from the light source 42. For example, the Ar flow rate is the flow rate of the Ar supplied to the inside of the housing 21 while maintaining the inside of the housing 21 at a prescribed pressure during the irradiation of the light. Therefore, when the flow rate of the Ar is increased, the amount of the gas discharged from the inside of the housing 21 to the outside is also increased, and thus the discharge of the impurities (sublimates and the like) generated in the inside of the housing 21 to the outside can be promoted. On the contrary, when the flow rate of the Ar is decreased, the impurities generated in the inside of the housing 21 are likely to remain in the inside of the housing 21. Therefore, a part of the light emitted from the light source 42 is absorbed or diffused by the impurities and the like. As a result, there is a possibility that the spectrum of the light irradiated to the wafer W is changed from the light from the light source 42. As described above, the Ar flow rate is an element which can affect the transmissivity and the wavelength characteristics of the light emitted from the light source 42.

[0077] Further, the lamp compensation value is a value related to the intensity of the light emitted from the light source 42, and when the compensation value is increased, the intensity of the light from the light source 42 becomes large, and the amount of the light reaching the resist pattern 13 becomes large. As described above, in either of the case where the Ar flow rate is increased and the case where the lamp compensation value is increased, the amount of the light reaching the resist pattern 13 becomes large. Therefore, compared with the case where the Ar flow rate is decreased and the case where the lamp compensation value is decreased, the reaction in the resist pattern 13 can be promoted.

[0078] Details are described later, but in the case of the resist material for EUV lithography, it is difficult to absorb the light from the light source 42 including VUV light, and the responsiveness to the light from the light source 42 is low, compared with the resist material for other uses. Therefore, the operation of sufficiently irradiating the light from the light source 42 is effective for the modification of the resist pattern 13. Therefore, compared with the case of modifying the resist material for other uses, the Ar flow rate is increased to increase the transmissivity of the light, and the lamp compensation value is increased to increase the light amount, whereby the modification of the resist pattern 13 can be more appropriately performed.

[0079] (Improvement of roughness of surface)

[0080] (Evaluation Test 1)

[0081] As the evaluation test 1, the change in LWR (line width roughness) was evaluated for the case where the rotation speed of the wafer was changed in three conditions and the case where the current compensation value of the lamp at the time of irradiating the light from the light source 42 was changed in two conditions. The LWR is an index of the roughness of the pattern, and the smaller the value, the smaller the roughness of the surface of the pattern. The objects of the evaluation were the resist pattern 13 and the pattern in the lower layer film at the time of etching the lower layer film using the resist pattern 13 as a mask.

[0082] As the objects of the evaluation, a wafer W on which the resist pattern 13 was formed on the SOC film 11 and the SOG film 12 was prepared. Also, the pattern size of the wafer W was made 20 nm. The resist pattern 13 was composed of PMMA (polymethyl methacrylate resin) and PHS as the resin material, and in order to improve the roughness and the like, a resist material in which a photodecomposable quencher was added as an additive in addition to a PAG and a quencher was used.

[0083] In the housing 21 of the substrate processing apparatus 1, the wafer W on which the resist pattern 13 was formed on the surface was accommodated, and the inside of the housing 21 was depressurized. After the inside of the housing 21 reached the set pressure, the light was irradiated with the light source 42. The series of operations was the same as the above-described substrate processing method. The irradiation amount was changed in two stages of 50 mj / cm 2 and 75 mj / cm 2 . Also, as for the rotation speed of the wafer at the time of irradiating the light with the light source 42, the number of rotations of the wafer during the irradiation of the prescribed amount of light was changed in three stages of one rotation, three rotations, and five rotations. Also, the compensation value (current compensation value) of the lamp in the light source 42 was changed in two stages of 2.5 and 3.5. Under the conditions where the above-described set values were changed, the LWR was measured for the resist pattern 13 (ADI) and the pattern in the lower layer film at the time of etching the lower layer film using the resist pattern 13 as a mask (AEI), respectively. Furthermore, the Ar flow rate at the time of irradiating the light with the light source 42 was made 20 mL.

[0084] In Figure 7 , the measurement results of the LWR are shown. In Figure 7 , the measurement results at the time of the operation of irradiating light (VUV light) from the light source 42 using the substrate processing apparatus 1 are not shown as reference values (Ref). Further, the measurement results at the time of the irradiation amount of 50 mj / cm 2 and the rotation number of 1, the irradiation amount of 75 mj / cm 2 and the rotation number of 1, 3, 5 are shown. Further, the measurement results at the time of the irradiation amount of 50 mj / cm 2 and the rotation number of 1, and the irradiation amount of 75 mj / cm 2 and the rotation number of 1 are shown.

[0085] As Figure 7 shown, it is confirmed that the LWR of the underlayer film pattern (AEI) is lower than that of the resist pattern 13 (ADI) in either case of the irradiation amount of 50 mj / cm 2 and the irradiation amount of 75 mj / cm 2 . Further, in the case of the irradiation amount of 75 mj / cm 2 , the LWR of the underlayer film pattern (AEI) is lower than that in the case of the irradiation amount of 50 mj / cm 2 in the case of the lamp compensation value of 2.5 and the rotation number of 1. From the above, it can be inferred that the etching resistance of the resist pattern 13 is more improved and the roughness of the surface in the underlayer film pattern (AEI) is more improved in the case of the irradiation amount of 75 mj / cm 2 .

[0086] In addition, in the case of the irradiation amount of 50 mj / cm 2 , the measurement results of the LWR of the underlayer film pattern (AEI) change between the case of the lamp compensation value of 2.5 and the case of the lamp compensation value of 3.5, and the LWR is smaller in the case of the lamp compensation value of 3.5. In contrast, in the case of the irradiation amount of 75 mj / cm 2 , the measurement results of the LWR of the underlayer film pattern (AEI) hardly change between the case of the lamp compensation value of 2.5 and the case of the lamp compensation value of 3.5. Further, in the case of the lamp compensation value of 3.5, the measurement results of the LWR hardly differ between the case of the irradiation amount of 50 mj / cm 2 and the case of the irradiation amount of 75 mj / cm 2 . From the above, it can be inferred that the etching resistance of the resist pattern 13 is more improved and the roughness of the surface in the underlayer film pattern (AEI) is more improved in the case of the irradiation amount of 50 mj / cm 2and the lamp compensation value is 2.5, the cleavage and cross-linking reactions of chemical bonds caused by the light from the light source 42 including VUV light do not sufficiently proceed, and the improvement of LWR is insufficient (there is room for further improvement). On the other hand, it is presumed that, in the case where the irradiation amount is 50 mj / cm 2 and the lamp compensation value is 3.5 and the irradiation amount is 75 mj / cm 2 , the cleavage and cross-linking reactions of chemical bonds caused by the light from the light source 42 including VUV light proceed to some extent.

[0087] (About the effect of the rotation speed)

[0088] Next, in the case where the lamp compensation value is 2.5 and the irradiation amount is 75 mj / cm 2 , the LWR of the resist pattern 13 (ADI) is approximately the same in the three cases where the number of rotations is changed to 1, 3, and 5. On the other hand, it is confirmed that the LWR of the underlayer film pattern (AEI) is further improved (the LWR becomes smaller) in the case where the rotation speed is small. As a result, in the case where the same irradiation amount of light (VUV light) is irradiated to the resist pattern 13, the tendency of the light invading into the inside of the resist pattern 13 changes depending on the rotation speed. Further, in the case of the resist pattern 13 described in the present embodiment, the improvement effect of the LWR can be improved by reducing the rotation speed. This point will be described with reference to Figure 8 .

[0089] Figure 8 is a graph illustrating the change in the intensity of light received by a specific position on the wafer W depending on the change in the relative position of the light source 42 from the wafer W when the wafer W is rotated. Figure 8 (a) of is a graph showing the irradiation range of light from the light source 42. Figure 8 The irradiation position CO shown in (a) of is a position (directly below) corresponding to the point light source 44 in the light source 42, and the intensity of light from the light source 42 is the largest. On the other hand, the intensity of light becomes smaller as it departs from the irradiation position CO corresponding to the point light source 44, and the intensity of light is the smallest at the irradiation position CI at the end. As described above, depending on the positional relationship of a specific position on the wafer W from the light source 42, the amount of light at the position greatly changes. Therefore, in the substrate processing apparatus 1, it is attempted to make the amount of light received at each position on the surface of the wafer W uniform to some extent by rotating the wafer W.

[0090] In (b) of Figure 8 , the movement of the wafer W with respect to a specific point (hereinafter referred to as a specific point) of the light source 42 in the case where the wafer W is rotated is schematically shown by an arrow R1. In Figure 8In (b) of FIG. 4, it is shown that the four light sources 42 are arranged in positions corresponding to the irradiation position CO. By rotating the wafer W, a certain point on the wafer W is rotated along the arrow Rl. At this time, the wafer W passes through two irradiation positions CO and four irradiation positions Cl. As described above, the irradiation position CO is a position where the intensity of light from the light source 42 is the greatest, and the irradiation position Cl is a position where the intensity of light from the light source 42 is the least. That is, in the case where the certain point on the wafer W moves (rotates) along the arrow Rl, the intensity of light received by the certain point changes in correspondence with the action of passing through the two positions of the irradiation position CO and the irradiation position Cl. Figure 8 In (c) of FIG. 4, it is shown that the four light sources 42 are arranged in positions corresponding to the irradiation position Cl. By rotating the wafer W, a certain point on the wafer W is rotated along the arrow Rl. At this time, the wafer W passes through two irradiation positions Cl and four irradiation positions CO. As described above, the irradiation position Cl is a position where the intensity of light from the light source 42 is the least, and the irradiation position CO is a position where the intensity of light from the light source 42 is the greatest. That is, in the case where the certain point on the wafer W moves (rotates) along the arrow Rl, the intensity of light received by the certain point changes in correspondence with the action of passing through the two positions of the irradiation position Cl and the irradiation position CO. Figure 8 In (d) of FIG. 4, a graph schematically showing the change in the intensity of light received by the certain point on the wafer W moving along the arrow Rl is shown. Figure 8 In the example shown in (d) of FIG. 4, the rotational speed is increased as compared with (c) of FIG. 4. In the case where the rotational speed is increased, the moving path of the certain point (corresponding to the arrow Rl) does not change, and thus the certain point passes through the two positions of the irradiation position CO and the irradiation position Cl. However, in the case where the rotational speed is large, the speed of change in the intensity of light received by the certain point also becomes large. Figure 8 In the case where the intensity of light is large (for example, at the irradiation position CO and the like in (b) of FIG. 4), either the light of a wavelength band having a large intensity or the light of a wavelength band having a small intensity among the VUV light from the light source 42 becomes likely to intrude into the resist pattern 13. On the other hand, in the case where the intensity of light is small (for example, at the irradiation position Cl and the like in (c) of FIG. 4), the light of a wavelength band having a large intensity among the VUV light from the light source 42 intrudes into the resist pattern 13, but the light of a wavelength band having a small intensity is difficult to intrude into the resist pattern 13. That is, in the case where the intensity of light is small, with respect to the light of a wavelength band having a small intensity among the VUV light, it is not possible to irradiate a sufficient amount of light for promoting the modification in the resist pattern 13.

[0091] Figure 8 In the case where the intensity of light is large (for example, at the irradiation position CO and the like in (b) of FIG. 4), either the light of a wavelength band having a large intensity or the light of a wavelength band having a small intensity among the VUV light from the light source 42 becomes likely to intrude into the resist pattern 13. On the other hand, in the case where the intensity of light is small (for example, at the irradiation position Cl and the like in (c) of FIG. 4), the light of a wavelength band having a large intensity among the VUV light from the light source 42 intrudes into the resist pattern 13, but the light of a wavelength band having a small intensity is difficult to intrude into the resist pattern 13. That is, in the case where the intensity of light is small, with respect to the light of a wavelength band having a small intensity among the VUV light, it is not possible to irradiate a sufficient amount of light for promoting the modification in the resist pattern 13. Figure 8

[0092] In addition, the resist material used in the present embodiment, which is suitable for EUV lithography, has a low responsiveness to light from the light source 42 as compared with a resist material for other uses, and is difficult to absorb light from the light source 42 including VUV light. Thus, even in the case where the intensity of light is large, the light of a wavelength band having a small intensity among the VUV light is difficult to intrude into the resist pattern 13 when the rotational speed is increased. Thus, in the case where the rotational speed is decreased as compared with the case where the rotational speed is large as shown in (d) of FIG. 4, it is possible to increase the intrusion rate of light into the resist pattern 13, and it is possible to promote the cleavage of chemical bonds and the crosslinking reaction in the resist pattern 13. The cleavage of chemical bonds and the crosslinking reaction contribute to the improvement of etching resistance. Figure 7 Figure 7 ​​​In the results shown, it was confirmed that the LWR was approximately the same degree with respect to the resist pattern 13 (ADI), while the LWR was smaller in the case of a smaller rotational speed than in the case of a larger rotational speed with respect to the underlayer film pattern (AEI), and the roughness of the surface was improved. That is, the effect of improving the etching resistance of the resist pattern 13 was different depending on the rotational speed, and as a result, the LWR of the underlayer film pattern (AEI) after use as a mask was changed. In this way, in the case where the light from the light source 42 containing VUV light is irradiated to the resist pattern 13 of the EUV lithography resist material, the time during which the light is continuously irradiated is important. That is, compared to the case where the rotational speed is increased in consideration of the in-plane uniformity of light irradiation, it is preferable to continuously maintain a state where the intensity of the light is large (for example, the time through C0) and to ensure this state for a long time so that the light sufficiently intrudes into the resist pattern 13 at each position. By achieving the state as described above, it is possible to improve the effect of improving the roughness of the surface of the underlayer film pattern.

[0093] Further, as a specific rotational speed, for example, it is possible to cite a range of 1 to 4 rotations during irradiation of light having an irradiance of 75 mj / cm2to the wafer W. This value corresponds to, for example, in the case where the intensity of the light from the light source 42 is 0.8 mW / cm2, the necessary time for one treatment is 93.75 seconds, and thus, the rotational speed of the holding portion 26 is in the range of 0.5 rpm to 3 rpm. 2 Further, as a specific rotational speed, for example, it is possible to cite a range of 1 to 4 rotations during irradiation of light having an irradiance of 75 mj / cm2to the wafer W. This value corresponds to, for example, in the case where the intensity of the light from the light source 42 is 0.8 mW / cm2, the necessary time for one treatment is 93.75 seconds, and thus, the rotational speed of the holding portion 26 is in the range of 0.5 rpm to 3 rpm. 2

[0094] In addition, the rotational speed of the wafer W can also not be constant during irradiation of light from the light source 42. As described above, when the rotational speed is increased, the light of a wavelength band having a large intensity in the VUV light becomes easy to intrude into the resist pattern 13. Therefore, by irradiating the wafer W with light from the light source 42 while changing the rotational speed, it is also possible to adjust the irradiation of light from the light source 42 so that the light of a specific wavelength band becomes easy to intrude into the wafer W more.

[0095] (Regarding the intensity distribution caused by the position of the light source)

[0096] Further, in the case where a circular substrate such as the wafer W is rotated at a certain angular velocity, the moving speed with respect to the light source 42 and the positional relationship with the light source 42 are greatly different between the inner side (the vicinity of the center) and the outer side (the vicinity of the end) of the wafer W. Specifically, when the distance from the center of rotation is larger, the actual moving speed becomes larger, and thus, the moving speed of the inner side of the wafer W with respect to the light source 42 becomes smaller, and the moving speed of the outer side with respect to the light source 42 becomes larger. In addition, in the inner side and the outer side of the wafer W, the irradiation area that passes during one rotation of the wafer W is greatly different. For example, in the case where the light source 42 is configured so that the light source 42 is disposed on the outer side of the wafer W, the irradiation area that passes during one rotation of the wafer W is larger than in the case where the light source 42 is disposed on the inner side of the wafer W. Figure 3 ​In this case, on the inner side of the wafer W, the irradiation area by the 4 light sources 42 on the inner side passes through during one rotation of the wafer W. On the other hand, on the outer side of the wafer W, the irradiation area by the 8 light sources 42 on the outer side passes through during one rotation of the wafer W. Therefore, the closer to the outer side of the wafer W, the more the irradiation area by the light sources 42 passes through, and the number of times of passing through the area with a large intensity of light increases. In this way, even if the wafer W rotates at a certain speed, the light received by the resist pattern 13 on the surface of the wafer W (particularly, the speed of change in intensity of the light irradiated) differs depending on the position of the wafer W (particularly, the distance from the center of rotation). As a result, the degree of improvement in the roughness of the surface of the resist pattern 13 differs depending on the position of the surface of the wafer W. In addition, in Figure 3 the case of the configuration shown in FIG. 6, on the outer side of the wafer W, the time period during which only one of the area with a large intensity of light and the area with a small intensity of light of the light from the light source 42 passes through is shortened. Therefore, the wafer W is strongly affected by the time period during which the area with a large intensity of light of the light from the light source 42 passes through, and the modification of the resist pattern 13 caused by the light can be promoted.

[0097] In Figure 9 , an example of the distribution of the illuminance of the light received at each position of the wafer W (distribution of the amount of light irradiated) in a case where the wafer W is rotated on one side and light is irradiated from a plurality of light sources 42 is shown. Here, the configuration of the light sources 42 is as shown in Figure 3 . In Figure 9 the example shown in FIG. 5, it is confirmed that a deviation in the illuminance of the light received on the surface of the wafer W occurs on the outer side and the inner side of the wafer W. Specifically, on the area Wl on the outer side of the wafer W, the illuminance of the light received is moderate, and, in contrast to this, on the area W2 on the inner side of the wafer W, the illuminance of the light received is low (the color on the area W2 is on the Min. side). In addition, in the vicinity of the center, there is also an area between the area Wl and the area W2 in which the illuminance changes depending on the distance from the center. As a reason for such a deviation in the illuminance of the light, as described above, the reason that the speed of movement of the wafer W with respect to the light sources 42 differs depending on the position of the wafer W can be given. In addition, the reason that the manner in which the area with a strong intensity (for example, the irradiation position C0 in Figure 8 , etc.) and the area with a weak intensity (for example, the irradiation position C1 in Figure 8 , etc.) of the irradiation area of each light source 42 differs depending on the position of the wafer W is also a reason. Such a deviation in the distribution of the illuminance also affects a deviation in the improvement effect on the roughness of the surface of the resist pattern 13 and the lower layer film pattern.

[0098] In a case where a deviation in the intensity distribution occurs (particularly in the radial direction) at each position on the surface of the wafer W, as a method for improving this, it is considered to change the intensity of the light irradiated on the wafer W from the plurality of light sources 42.

[0099] The specific method for making the intensity of the light irradiated on the wafer W from the light sources 42 different based on the position of the wafer W (particularly, the inner side and the outer side) is not particularly limited. For example, it is considered to change the arrangement of the light sources 42, the number of the light sources 42, the intensity of the light output from each light source 42, and the like. For example, by making the light sources 42 closer to each other in such a manner that the end portions of the irradiation regions overlap each other, it is possible to increase the amount of light received by the wafer W when passing through the overlapping region. Therefore, by adjusting the size of the overlapping region and the like, it is also possible to adjust the amount of light received by the resist pattern 13. As described above, by changing various configurations related to the light sources 42, it is possible to achieve a configuration in which the intensity of the light irradiated on the wafer W from the light sources 42 is made different based on the position of the wafer W (particularly, the inner side and the outer side). Figure 3 For example, by making the current compensation values of the four light sources on the inner side 3.5 and the current compensation values of the eight light sources on the outer side 2.5, it is possible to make the intensity of the light output from the light sources 42 on the inner side larger than the intensity of the light from the light sources on the outer side. Furthermore, by changing the arrangement of the light sources and the like, rather than by changing the current compensation values and the like, it is also possible to reduce the deviation in the intensity distribution as shown in FIG. 8, for example. Figure 9 As described above, the light output from the light sources 42 has a large difference in intensity near the center (CO) and near the end portion (Cl) within the irradiation region. Furthermore, near the center (CO) and near the end portion (Cl), the degree to which the light reaches a deep layer in the resist pattern 13 when passing through this region, the degree of modification of the resist pattern 13 based on the received light, has a large difference. Also, for adjacent light sources 42, by arranging them closer to each other in such a manner that the end portions of the irradiation regions overlap each other, it is possible to increase the amount of light received by the wafer W when passing through the overlapping region. Therefore, by adjusting the size of the overlapping region and the like, it is also possible to adjust the amount of light received by the resist pattern 13. As described above, by changing various configurations related to the light sources 42, it is possible to achieve a configuration in which the intensity of the light irradiated on the wafer W from the light sources 42 is made different based on the position of the wafer W (particularly, the inner side and the outer side).

[0100] Furthermore, the "inner side" and the "outer side" of the wafer W indicate a relative positional relationship. Therefore, where the boundary between the inner side and the outer side is not particularly limited. Based on the number of the light sources 42 and the arrangement thereof, it is possible to change the site at which the deviation in the intensity distribution along the radial direction of the wafer W occurs. However, since the light is irradiated from the light sources 42 while the wafer W is rotated, the moving speed of the wafer W becomes smaller on the inner side and larger on the outer side. Therefore, it is more difficult for the inner side of the wafer W to receive sufficient light for the modification (cleavage of chemical bonds and crosslinking reaction) of the resist pattern 13 than for the outer side of the wafer W. In view of this, it is sufficient to adopt a configuration in which the intensity of the light irradiated on the wafer W from the light sources 42 is made different on the inner side and the outer side of the wafer W.

[0101] (Influence of additives in resist materials for EUV lithography)

[0102] In the above-described evaluation test 1, the resist pattern 13 was formed of PMMA (polymethyl methacrylate resin) as the resin material, and a resist material to which a photodecomposition-type quencher was added as an additive was used. However, in EUV lithography, the amount of addition of the additive also has a large influence on the optical characteristics of the resist, and thus the amount of addition of the additive is sometimes changed. Therefore, regarding changes in the optical characteristics of the resist pattern 13 (particularly, changes in the case where light from the light source 42 containing VUV light is irradiated) by changing the amount of addition of the additive, the results of the study are given. In the following evaluation test, the same resin material as that used in the above-described evaluation test 1 was used, and the same kind of photodecomposition-type quencher was selected as the additive.

[0103] (Evaluation test 2 and results)

[0104] Three kinds of resist materials to which the same kind of photodecomposition-type quencher was added as an additive were prepared using the same resin material as that used in the evaluation test 1. Among them, the amount of addition of the additive was different among the three kinds of resist materials. Here, the three kinds of resist materials are referred to as resist A, resist B, and resist C.

[0105] Among the three kinds of resist materials, the resist A was the same as the resist material used in the evaluation test 1. Further, the amounts of addition of the photodecomposition-type quencher were increased in the resist B and C as compared with the resist A (the amount of addition per unit weight of the resist material). Further, the amounts of addition of the photodecomposition-type quencher had a relationship of A < B < C.

[0106] Three kinds of test wafers were prepared by forming the resist pattern 13 of the above-described three kinds of resist materials on the SOC film 11 and the SOG film 12, respectively. Further, the pattern sizes of the respective resist materials were different from each other, and the resist A was 20 nm, the resist B was 19 nm, and the resist C was 22 nm. It is known that in general, the larger the pattern size of the resist material, the smaller the LWR associated with the roughness of the surface.

[0107] In the substrate processing apparatus 1, the LWR was measured after each of the test wafers was irradiated with light from the light source 42 at a prescribed irradiance. The results are shown in FIG. 6. Figure 10 Figure 10 The horizontal axis of FIG. 6 is the irradiance of the light (containing VUV light) emitted from the light source 42. The irradiance 0 mj / cm 2 means that the light was not irradiated on the resist pattern 13 from the light source 42.

[0108] As Figure 10 ​As shown, it was confirmed that, regardless of whether light was irradiated from light source 42, the LWR decreased in the order of resists A, B, and C. Furthermore, for resist A, when the irradiance of light from light source 42 was increased to 100 mJ / cm², the LWR decreased. 2 Under certain conditions, LWR becomes approximately minimal, while for resists B and C, the irradiance from light source 42 is 50–75 mJ / cm. 2 Under certain conditions, the LWR becomes approximately minimal. As stated above, it has been confirmed that even with the same type of additives, the properties of the resist relative to light from the light source 42 containing VUV light vary depending on the amount added.

[0109] (Evaluation of Experiment 3 and Results)

[0110] For resist A and resist B, two test wafers were prepared, each coated flatly onto SOC film 11 and SOG film 12 respectively, and the resist film thickness was measured. Then, in substrate processing apparatus 1, each test wafer was irradiated with a specified amount of light from light source 42, and the resist film thickness was measured, along with the change in resist film thickness caused by light irradiation. Furthermore, the irradiated resist was etched under specified conditions, and the change in film thickness caused by etching was measured. On the other hand, as a comparison, the same test wafers were prepared, but etched under the same conditions without light source 42, and the change in film thickness caused by etching was measured.

[0111] Based on the above measurement results, it can be seen that the etching depth differs under the same conditions depending on whether light is irradiated from light source 42. Therefore, it is possible to evaluate the extent to which etching tolerance is improved by irradiation from light source 42. Furthermore, the resist film thickness changes (the film thickness decreases) due to the modification of the resist material caused by irradiation from light source 42 (the breaking of chemical bonds and cross-linking reactions). Figure 11 This indicates the result of evaluating how the etching tolerance changes when illuminated by light source 42, based on this change. Figure 11 The horizontal axis represents the irradiance of light (including VUV light) emitted from light source 42. The vertical axis represents the degree of improvement in etch resistance. Furthermore, since changes in the surface layer of the resist material due to light irradiation were observed, the etching time was shortened, for example, to 5 seconds or less, and this was evaluated.

[0112] like Figure 11 As shown, it was confirmed that: resist A increased with the amount of light (irradiance) from light source 42 from 100 mJ / cm 2 Increased to 200 mJ / cm 2The improvement in etching resistance gradually progresses. On the other hand, it is confirmed that the improvement in etching resistance of resist B progresses to a certain degree in the case where the irradiation amount of light from the light source 42 is small (100 mj / cm 2 ) and hardly changes even if the irradiation amount is increased. As described above, the amount of addition of the photodegradable quencher is larger in resist B than in resist A, and thus the improvement in etching resistance changes as shown in Figure 11 . As described above, regarding the resist material for EUV lithography, the degree of change or the tendency thereof in the characteristics in the resist pattern when light containing VUV light is irradiated can change depending on the kind or the amount of addition of the additive.

[0113] (Difference in improvement tendency of roughness of surface due to the amount of addition of additive)

[0114] (Evaluation Test 4)

[0115] As Evaluation Test 4, the improvement in roughness of the surface when each condition related to the irradiation of light is changed was evaluated for resist C as well as for resist A. Figure 12 is a graph showing the results of Evaluation Test 4.

[0116] Specifically, the change in LWR (line width roughness) was evaluated for the case where the rotation speed of the wafer was changed in 2 conditions and for the case where the lamp current compensation value when light is irradiated from the light source 42 was changed in 2 conditions. The object of evaluation was the resist pattern 13 and the pattern in the underlayer film when the etching of the underlayer film was performed using the resist pattern 13 as a mask. The constitution of the wafer W used was the same as in the case of resist A described in Figure 7 . Further, the resist material used was resist C, and the amount of addition of the photodegradable quencher was larger than in resist A.

[0117] Inside the housing 21 of the substrate processing apparatus 1, the wafer W on the surface of which the resist pattern 13 was formed was accommodated, and the inside of the housing 21 was depressurized. After the set pressure was reached inside the housing 21, light was irradiated with the light source 42. The series of operations was the same as the substrate processing method described above. The irradiation amount was changed to 50 mj / cm 2 , 75 mj / cm 2This 2 levels. In addition, regarding the rotation speed of the wafer at the time of irradiation of light with the light source 42, the number of rotations of the wafer during the period of irradiation of a prescribed amount of light was changed in 2 levels of 1 rotation and 3 rotations. Also, the compensation value (current compensation value) of the lamp in the light source 42 was changed in 2 levels of 2.5 and 3.5. Under the conditions in which the above-described set values were changed, LWR was measured for the resist pattern 13 (ADI) and the pattern in the lower layer film (AEI) at the time of etching of the lower layer film using the resist pattern 13 as a mask. In addition, the Ar flow rate at the time of irradiation of light with the light source 42 was made to be 20 mL.

[0118] In Figure 12 , the measurement results of LWR are shown. In addition, in Figure 12 , the measurement results at the time of irradiation of light (VUV light) from the light source 42 without using the substrate processing apparatus 1 are shown as a reference value (Ref). In addition, the measurement results in the case where the lamp compensation value was 2.5, the irradiation amount was 50 mj / cm 2 , and the number of rotations was 1 and 3, and the measurement results in the case where the lamp compensation value was 3.5, the irradiation amount was 75 mj / cm 2 , and the number of rotations was 1 are shown. 2

[0119] In Figure 12 , it was confirmed that in either case of the irradiation amount of 50 mj / cm 2 and the irradiation amount of 75 mj / cm 2 , LWR of the lower layer film pattern (AEI) was lower than that of the resist pattern 13 (ADI). In addition, in the case where the lamp compensation value was 2.5 and the case where the lamp compensation value was 3.5, LWR was approximately the same value. From the above, it can be inferred that in either condition, etching resistance in the resist pattern 13 was improved, and the roughness of the surface in the lower layer film pattern (AEI) was improved. From the results shown in Figure 11 , it can be inferred that when the amount of addition of the photodecomposition type quenching agent is increased, the responsiveness of the resist material to light from the light source 42 is improved, and Figure 12 the results shown in Figure 11 are consistent with the inference based on the results thereof.

[0120] In addition, it was confirmed that in the case where the lamp compensation value was 2.5 and the irradiation amount was 50 mj / cm 2 ​The LWR of the resist pattern 13 (ADI) was approximately the same in the two results when the number of rotations was changed to 1 and 3. On the other hand, it was confirmed that the LWR of the underlayer film pattern (AEI) was slightly smaller when the number of rotations was 1. This tendency was the same as in the case of Evaluation Test 1 (resist A). As described above, the characteristics of the resist material can change depending on the amount of additive added. However, the same tendency was exhibited in the results of Evaluation Test 4 in the resists A and C, and thus it can be inferred that the same tendency is exhibited when a general EUV lithography resist material is used. That is, it is known that the tendency of the roughness of the surface of the resist material to improve can be exhibited by adding an additive, but in the case of irradiation with VUV light, the improvement effect can be further improved regardless of the amount of irradiation.

[0121] [Effects]

[0122] As described above, in the above-described substrate processing apparatus 1 and substrate processing method, the number of rotations of the substrate at the time of irradiation of light from the light source 42 with the substrate is set to 0.5 rpm to 3 rpm. By adopting such a configuration, light in the vacuum ultraviolet range, and particularly light on the low wavelength side, becomes easy to intrude into the pattern, and thus the improvement effect of the roughness of the surface can be improved. As described above, the pattern formed of the EUV lithography resist material has low responsiveness to light, and thus it is required to irradiate vacuum ultraviolet light in a manner of a certain time interval. In contrast, by adopting the above-described configuration, particularly light on the low wavelength side having low light intensity also becomes easy to intrude into the pattern, and thus the improvement effect of the roughness of the surface can be improved.

[0123] In addition, a configuration in which the number of rotations of the substrate during irradiation of light from the light source 42 is changed can be adopted. Based on the number of rotations of the substrate at the time of irradiation of light, the composition of light that intrudes into the pattern can be changed. Thus, by adopting a configuration in which light is irradiated while the number of rotations is changed, light having a composition suitable for improvement of the roughness of the surface can be made to intrude into the pattern, and thus the improvement effect of the roughness of the surface can be further improved. Furthermore, the number of rotations of the substrate during irradiation of light from the light source 42 can be further changed to a stopped state, that is, to a state in which the rotation of the substrate is temporarily stopped. Even with such a configuration, the composition of light that intrudes into the pattern can be changed, and thus the improvement effect of the roughness of the surface can be further improved. The time at the time of temporary stop and the like can be appropriately adjusted depending on the pattern and the like.

[0124] Further, a gas supply section 30 for supplying a non-active gas into the processing container and a gas exhaust section 35 for exhausting the gas from the processing container are included. At this time, the gas supply section 30 and the gas exhaust section 35 can be configured to supply and exhaust the gas while changing the pressure in the processing container during the period when the light is irradiated by the light source section. By adopting such a configuration, the vacuum ultraviolet light can be irradiated to the pattern while the pressure in the processing container is made to be a state corresponding to the surface condition of the substrate.

[0125] The above describes various exemplary embodiments, but is not limited to the above-described exemplary embodiments, and various omissions, substitutions, and changes can be made. Further, elements in different embodiments can be combined to form other embodiments.

[0126] For example, the configuration and number of the light source 42 in the substrate processing apparatus 1 can be appropriately changed. Further, a component or the like for controlling the origin of the light emitted from the light source 42 can be added. Further, the configuration and constitution of each section in the substrate processing apparatus 1 can be appropriately changed. Further, the control of the pressure or the like described in the above-described embodiments is only an example, and can be changed to control the pressure in the housing 21 also at a stage before the light is irradiated from the light source 42.

[0127] In accordance with the above description, various embodiments of the present application are described in the specification for the purpose of illustration, and it should be understood that various changes can be made without departing from the scope and spirit of the present application. Therefore, the various embodiments disclosed in the specification are not limiting, and the true scope and spirit are given by the scope of the appended claims.

Claims

1. A substrate processing apparatus, characterized in that: The substrate processing apparatus processes the pattern formed on the surface of the substrate by the resist material used for EUV lithography. The substrate processing apparatus includes: The substrate is held within the processing container; A rotation drive unit that rotates the holding part; A light source section having multiple light sources irradiates the surface of the substrate held by the holding section with light comprising vacuum ultraviolet light; and Control Department The intensity of the light emitted by the light source varies in a manner that is greatest at a first illumination position corresponding to the light source, decreases as one moves away from the first illumination position, and is minimum at a second illumination position at the end of the illumination range of the light source. The light irradiated by the light source forms a continuous spectrum, which is in the range of 10 nm to 200 nm and includes light with wavelengths longer than 160 nm and light with wavelengths shorter than 160 nm. The control unit controls the rotation drive unit so that a specific point on the substrate located between the center and the outer edge of the substrate passes through both the first irradiation position and the second irradiation position. During the period when the light source irradiates the light, the rotation drive unit changes the rotational speed of the substrate so that the composition of the intrusion pattern in the continuous spectrum changes at that specific point.

2. The substrate processing apparatus as described in claim 1, characterized in that: The substrate is temporarily stopped rotating during the period when it is irradiated with light from the light source.

3. The substrate processing apparatus as described in claim 1, characterized in that: It includes a gas supply unit for supplying inactive gas into the processing container and a gas discharge unit for discharging gas from the processing container. The gas supply unit and the gas discharge unit supply and discharge gas while the light source unit irradiates the process container by changing the pressure inside the container.

4. A substrate processing method, characterized in that: The substrate processing method uses a substrate processing apparatus to process patterns formed on the surface of a substrate by an EUV lithography resist material. The substrate processing apparatus includes: Maintenance section; Rotary drive unit; and A light source unit with multiple light sources; and Control Department The substrate processing method includes: The holding step involves holding the substrate within the processing container using the holding part; The rotation step involves rotating the holding part using the rotation drive unit; and In the irradiation step, the light source irradiates the surface of the substrate held by the holding part with light including vacuum ultraviolet light. The light forms a continuous spectrum, which is in the range of 10 nm to 200 nm and includes light with wavelengths longer than 160 nm and light with wavelengths shorter than 160 nm. In the irradiation step, the light intensity is irradiated in a manner such that it is maximum at a first irradiation position corresponding to the light source, decreases as it moves away from the first irradiation position, and minimum at a second irradiation position at the end of the irradiation range of the light source. In the rotation step The control unit controls the rotation drive unit so that a specific point on the substrate located between the center and the outer edge of the substrate passes through both the first irradiation position and the second irradiation position. During the illumination of light by the light source, the rotation drive unit changes the rotational speed of the substrate, so that at a specific point, the composition of the intrusion pattern in the continuous spectrum changes.

5. A computer-readable storage medium, characterized in that: The device stores a program for performing the substrate processing method of claim 4.

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