Substrate processing device, substrate processing method and storage medium

Abstract

The present invention provides a substrate processing device, a substrate processing method and a storage medium. The substrate processing device (1) includes: a holding portion for holding a substrate in a processing container, wherein the substrate has a pattern formed on the surface of a resist material for ArF immersion lithography; a rotation drive portion for rotating the holding portion; and a light source portion having a plurality of light sources, which irradiates the surface of the substrate held by the holding portion rotated by the rotation drive portion with light containing vacuum ultraviolet light, so that the irradiation amount of light irradiated from the light source portion to the inner side of the substrate is greater than the irradiation amount of light irradiated from the light source portion to the outer side of the substrate. The present invention can improve the surface roughness on a substrate using a resist material suitable for ArF immersion lithography.

Description

Technical Field

[0001] The present invention relates to a substrate processing apparatus, a substrate processing method, and a storage medium. Background Art

[0002] Patent Document 1 discloses a technique in which, in a manufacturing process of a semiconductor device, the following steps are sequentially performed: a step of irradiating the front surface of a resist that has been patterned after exposure and formed on the surface of a substrate with light having a wavelength of 200 nm or less; and a step of etching the underlying film of the resist film. The step of irradiating light having a wavelength of 200 nm or less (hereinafter, simply referred to as the light irradiation step) aims to improve, for example, the roughness (unevenness) of the resist film.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent No. 3342856 Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] The present invention provides a technique capable of improving the surface roughness of a substrate using a resist material suitable for ArF immersion lithography.

[0008] Technical Solution for Solving the Technical Problem

[0009] A substrate processing apparatus according to one aspect of the present invention includes: a holding unit that holds a substrate in a processing container, wherein the substrate has a pattern formed on its surface using a resist material for ArF immersion lithography; a rotation driving unit that rotates the holding unit; and a light source unit having a plurality of light sources, which irradiates the surface of the substrate held by the holding unit rotated by the rotation driving unit with light containing vacuum ultraviolet light, and makes the irradiation amount of light irradiated from the light source unit to the inner side of the substrate larger than the irradiation amount of light irradiated from the light source unit to the outer side of the substrate.

[0010] A substrate processing method according to one aspect of the present invention irradiates the surface of a substrate with light containing vacuum ultraviolet light from a light source unit having a plurality of light sources while rotating the substrate in a processing container, wherein the substrate has a pattern formed on its surface using a resist material for ArF immersion lithography, and in this substrate processing method, the irradiation amount of light irradiated from the light source unit to the inner side of the substrate is made larger than the irradiation amount of light irradiated from the light source unit to the outer side of the substrate.

[0011] Advantageous Effects of the Invention

[0012] According to the present invention, a technique is provided for improving the surface roughness of a substrate using a resist material suitable for ArF immersion lithography. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 FIG. is a view showing a substrate processing apparatus according to an exemplary embodiment.

[0014] Figure 2 FIG. is a schematic view illustrating the processing of a substrate by the substrate processing apparatus.

[0015] Figure 3 FIG. is a schematic view illustrating the arrangement of a light source in the substrate processing apparatus.

[0016] Figure 4 FIG. is a block diagram illustrating the functional configuration of a controller.

[0017] Figure 5 FIG. is a block diagram illustrating the hardware configuration of a controller.

[0018] Figure 6 FIG. is a graph showing the pressure change during substrate processing in the substrate processing apparatus.

[0019] Figure 7 FIG. is a graph showing the results of Evaluation Test 1.

[0020] Figure 8 FIG. is a graph showing the results of Evaluation Test 2.

[0021] Figure 9 FIG. is a graph showing the results of Evaluation Test 3.

[0022] Figure 10 FIG. is a graph showing the results of Evaluation Test 4.

[0023] Figure 11 FIG. is a graph showing the results of Evaluation Test 5.

[0024] Figure 12 FIG. is a graph showing the results of Evaluation Test 6.

[0025] Figure 13 FIG. is a graph showing the change in the intensity of light received by a rotating substrate.

[0026] Figure 14 FIG. is a graph showing the illuminance distribution in a substrate.

[0027] REFERENCE MARK DESCRIPTION

[0028] 1... Substrate processing apparatus; 13... Resist pattern; 20... Processing chamber; 21... Housing; 22... Transfer port; 23... Gate valve; 25... Rotating support portion; 26... Holding portion; 27... Rotation drive portion; 30... Gas supply portion; 35... Gas discharge portion; 40... Light irradiation mechanism; 41... Housing; 42... Light source; 44... Point light source; 100... Controller. Detailed implementation manners

[0029] Hereinafter, various exemplary implementation manners will be described.

[0030] In an exemplary implementation manner, the substrate processing apparatus includes: a holding portion that holds a substrate in a processing container, wherein a pattern made of an ArF immersion lithography resist material is formed on the surface of the substrate; a rotation drive portion that rotates the holding portion; and a light source portion having a plurality of light sources, which irradiates light including vacuum ultraviolet light onto the surface of the substrate held by the holding portion rotated by the rotation drive portion, such that the amount of light irradiated from the light source portion onto the inner side of the substrate is larger than the amount of light irradiated from the light source portion onto the outer side of the substrate.

[0031] In a substrate in which a pattern made of an ArF immersion lithography resist material is formed on the surface, the degree of improvement in the surface roughness of the pattern easily varies depending on the amount of light irradiation. In addition, when irradiating light while rotating the substrate, the moving speed of the substrate becomes slower toward the inner side, so the amount of light irradiation becomes less. In contrast, with the above-described substrate processing apparatus, it is possible to make the amount of light irradiated onto the inner side of the substrate larger than the amount of light irradiated onto the outer side of the substrate, so it is also possible to increase the amount of light irradiation onto the inner side of the substrate, and the improvement effect of the surface roughness can be improved.

[0032] It may also be the following manner: making the output intensity of the light source that irradiates light onto the inner side of the substrate larger than the output intensity of the light source that irradiates light onto the outer side of the substrate.

[0033] As described above, when making the amount of light irradiated onto the inner side of the substrate larger than the amount of light irradiated onto the outer side of the substrate by increasing the output intensity of the light source, it is possible to more simply adjust the amount of light irradiation between the inner side and the outer side of the substrate.

[0034] It may also be the following manner: making the time for irradiating light onto the inner side of the substrate and the time for irradiating light onto the outer side of the substrate different from each other.

[0035] As described above, when making the amount of light irradiated onto the inner side of the substrate larger than the amount of light irradiated onto the outer side of the substrate by making the irradiation time different between the inner side and the outer side of the substrate, it is possible to more simply adjust the amount of light irradiation between the inner side and the outer side of the substrate.

[0036] It may be in the following manner: including a gas supply unit that supplies an inert gas into the above-mentioned processing container and a gas discharge unit that discharges gas from the above-mentioned processing container. During the period when the above-mentioned light source unit irradiates light, the supply and discharge of the above-mentioned gas are carried out while changing the pressure inside the above-mentioned processing container.

[0037] As described above, during the period when the light source unit irradiates light, the supply and discharge of gas are carried out while changing the pressure inside the processing container. Thus, it is possible to make the pressure inside the processing container a state corresponding to the surface condition of the substrate while irradiating vacuum ultraviolet light on the pattern.

[0038] In an exemplary embodiment, the substrate processing method rotates the substrate inside the processing container while irradiating light including vacuum ultraviolet light on the surface of the above-mentioned substrate from a light source unit having a plurality of light sources. In the substrate, a pattern formed of an ArF immersion lithography resist material is formed on the surface. In this substrate processing method, the irradiation amount of light irradiated from the above-mentioned light source unit to the inside of the substrate is larger than the irradiation amount of light irradiated from the above-mentioned light source unit to the outside of the substrate.

[0039] According to the above-mentioned substrate processing method, it is possible to make the irradiation amount of light irradiated to the inside of the substrate larger than the irradiation amount of light irradiated to the outside of the substrate. Therefore, it is possible to increase the irradiation amount of light to the inside of the substrate and improve the improvement effect of the surface roughness.

[0040] In another exemplary embodiment, the storage medium is a computer-readable storage medium, and a program for causing a device to execute the above-mentioned substrate processing method is stored therein.

[0041] Hereinafter, various exemplary embodiments will be described in detail with reference to the drawings. In addition, the same or corresponding parts are denoted by the same reference numerals in the respective drawings.

[0042] [Structure of Substrate Processing Apparatus]

[0043] Figure 1 It is a schematic diagram (longitudinal cross-sectional side view) showing the substrate processing apparatus of the present embodiment. Figure 1 The shown substrate processing apparatus 1 irradiates light for processing on a wafer W (substrate). For example, the substrate processing apparatus 1 is configured to irradiate vacuum ultraviolet light (VUV light: Vacuum Ultra Violet Light) on a resist film or a resist pattern formed on the surface of the wafer W to improve the surface roughness of the above-mentioned resist material.

[0044] The wafer W is in the shape of a circular plate, but wafers having shapes other than circular, such as a part of a circular shape lacking or a polygon, can also be used. The wafer W can be, for example, various other substrates such as a semiconductor substrate, a glass substrate, a mask substrate, and an FPD (Flat Panel Display) substrate.

[0045] Figure 2 An example of processing the wafer W by the substrate processing apparatus 1 is shown. As Figure 2 shown in (a) of, in the wafer W, a resist pattern 13 is formed on the SOC film 11 (Silicon-on-Carbon) as the lower layer film and the 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 the processing light L1, the surface roughness of the resist pattern 13 is improved as Figure 2 shown in (b) of. In addition, the resist pattern 13 is a mask pattern for etching the SOC film 11 and the SOG film 12 as the lower layer films to form a pattern on the above-mentioned lower layer film.

[0046] Return Figure 1 , and each part of the substrate processing apparatus 1 will be described. The substrate processing apparatus 1 includes a processing chamber 20, a light irradiation mechanism 40 (light source unit), and a controller 100 (control unit) as Figure 1 shown. In addition, in Figure 1 , only a part of the structure included in the light irradiation mechanism 40 is shown.

[0047] The processing chamber 20 includes a housing 21, a transfer port 22, a rotary support portion 25, a gas supply portion 30, and a gas discharge portion 35. The housing 21 is, for example, a part of a vacuum container provided in an atmospheric atmosphere, and is configured to be able to accommodate the wafer W transported by a transport mechanism (not shown). In the substrate processing apparatus 1, the wafer W is processed in a state where the wafer W is accommodated in the housing 21. A transfer port 22 is formed in the side wall of the housing 21. The transfer port 22 is an opening for feeding and discharging the wafer W to and from the housing 21. The transfer port 22 is opened and closed by a gate valve 23.

[0048] The rotary support portion 25 has a function of holding the wafer W while rotating the wafer W based on an instruction from the controller 100 within the housing 21. The rotary support portion 25 includes, for example, a holding portion 26 and a rotation driving portion 27. The holding portion 26 supports the central portion of the horizontally disposed wafer W in such a manner that the surface on which the resist pattern 13 is formed faces upward, and holds the wafer W by, for example, vacuum adsorption. The rotation driving portion 27 has a function of rotating the holding portion 26 holding the wafer W together with the wafer W about a vertical axis A1. The rotation driving portion 27 is, for example, a rotary actuator having an electric motor as a power source.

[0049] The gas supply unit 30 is configured to supply an inert gas (e.g., argon, nitrogen, etc.) into the housing 21 through a through hole 21a formed in the housing 21. The gas supply unit 30 includes a gas source 30a, a valve 30b, and a pipe 30c. The gas source 30a stores the inert gas and functions as a supply source of the inert gas. The valve 30b operates based on an operation signal from the controller 100 to open and close 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 the upstream side.

[0050] The gas discharge unit 35 discharges the gas from the housing 21 through a through hole 21b formed in the housing 21. The gas discharge unit 35 includes a vacuum pump 35a and a pipe 35c. The vacuum pump 35a discharges the gas from inside the housing 21. The pipe 35c is connected to the through hole 21b and the vacuum pump 35a.

[0051] The light irradiation mechanism 40 includes a housing 41, a light source 42, and a switch 43. The housing 41 is provided on the upper part of the housing 21. A plurality of light sources 42 are accommodated in the housing 41. Figure 3 It is a plan view showing an example of the arrangement of the light sources 42. The light sources 42 are arranged along two concentric circles centered on the axis A1 that is the rotation axis of the holding part 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. In addition, the surface of the wafer W held by the holding part 26 is irradiated with light by the light sources 42 arranged as described above. In addition, the switch 43 switches the on and off of the lighting of the light sources 42. The operation of the switch 43 is controlled by the controller 100. In addition, the arrangement example of the light sources 42 is only one example and can be changed as appropriate.

[0052] The light source 42 irradiates light having a wavelength in the range of 115 nm to 400 nm, that is, light having a continuous spectrum in the range of 115 nm to 400 nm. The light having a continuous spectrum in this range may also include light having a wavelength of 10 nm to 200 nm (i.e., VUV light), and includes near-ultraviolet light (near-ultraviolet rays) having a wavelength longer than that of the VUV light. It is possible to make the light from the light source 42 include light in the region with a wavelength of 160 nm or less. The light source 42 is, for example, a deuterium lamp and is 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.

[0053] Since the wavelength band of the spectrum of the light irradiated from the light source 42 is relatively wide, 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, by cutting the chemical bonds at each position in the molecules constituting the resist pattern 13, various compounds are generated, so that the orientation of the molecules existing in the resist film before light irradiation can be eliminated. As a result, the surface free energy in 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 fluidity of the surface of the resist pattern 13 is likely to become high, and as a result, the improvement effect of the surface roughness can be enhanced.

[0054] In addition, in the resist pattern 13, a crosslinking reaction also occurs during and after the irradiation of light (especially VUV light) from the light source 42. Since the crosslinking reaction occurs simultaneously in the resist pattern 13, the surface of the resist pattern 13 is cured, and as a result, the etching tolerance becomes high. Therefore, when etching the underlying film using the resist pattern 13 as a mask, the roughness of the pattern surface in the underlying film can be improved.

[0055] The component of the light irradiated from the light source 42 with a wavelength shorter than 160 nm is very helpful for improving the roughness of the resist pattern 13 and the pattern surface in the underlying film. For example, it has been confirmed that when only light with a wavelength longer than 160 nm is irradiated onto the resist pattern, the improvement of the surface roughness cannot be sufficiently performed, and only the chemical bonds are cut. However, even when only light with a wavelength shorter than 160 nm is irradiated, the improvement of the surface roughness cannot be sufficiently performed. Therefore, light having a continuous spectrum including both light with a wavelength longer than 160 nm and light with a wavelength shorter than 160 nm, such as a deuterium lamp, is important for improving the surface roughness.

[0056] In addition, regarding the light from the light source 42 irradiated onto the resist pattern 13, the larger the wavelength, the deeper it can reach the resist pattern 13 when its intensity is greater. However, the wavelength of the peak of the spectrum of the light irradiated from the light source 42 is included in the wavelength band of VUV light (10 nm to 200 nm) as described above. Therefore, among the light irradiated from the light source 42, the intensity of the light with a relatively large wavelength is small. Therefore, the portion of the light irradiated from the light source 42 reaching the deep layer of the resist film is small, and the cutting of the above-mentioned molecular bonds in the deep layer of the resist film can be suppressed. That is, by using the light source 42, the region where the reaction occurs due to light irradiation can be limited to the surface in the resist pattern 13.

[0057] For light in the VUV light region, the situation is the same in that the depth of arrival of the light in the VUV light region in the resist pattern changes according to the wavelength. That is, as described above, compared with the light near the wavelength of 150 nm to 160 nm where the light intensity becomes maximum, the component with a longer wavelength can reach the deeper layer of the resist pattern 13 (for example, 150 nm or more). On the other hand, the component with a wavelength smaller than 150 nm only reaches the vicinity of the surface of the resist pattern 13 (for example, 50 nm or less). In addition, it is known that the component with a wavelength smaller than 150 nm has a lower intensity than the peak wavelength band among VUV light. That is, the component of light with a wavelength shorter than 160 nm, which helps improve the surface roughness, only reaches the vicinity of the surface of the resist pattern 13 (does not reach the deeper layer), and promotes the curing of the surface of the resist pattern 13 due to the crosslinking reaction near the surface. As described above, the component of light with a wavelength shorter than 160 nm is important for promoting the crosslinking reaction near the surface of the resist pattern 13. As described above, the light with a wavelength shorter than 160 nm has a greater influence on the resist pattern 13, and can promote the dissociation of side chains and the like of the components contained in the resist pattern 13, the reduction of internal stress, and the crosslinking reaction. On the other hand, when improving the film quality of the entire resist pattern 13, light with a wavelength longer than 160 nm is also required. Therefore, by irradiating the above-mentioned light in an appropriate balance, the improvement of the film quality can be achieved.

[0058] The light source 42 generates a top hat type of light with a flat intensity distribution compared to Gaussian distribution light. In addition, even for the top hat type of light, the intensity distribution is not completely flat. That is, light with an irradiation range emitted from the point light source 44 (refer to Figure 1 ) inside the light source 42 is irradiated, specifically, vacuum ultraviolet light with a conical optical path with the point light source 44 as the vertex is irradiated onto the wafer W. As described above, the light irradiated from the light source 42 has a circular irradiation range on the irradiation surface. In addition, in Figure 3 , the approximate propagation range of the light output from each light source 42 on the surface of the wafer W is indicated by a dashed line.

[0059] VUV light reacts with the oxygen in the atmosphere containing oxygen, so the effect of improving the roughness of the resist pattern 13 is reduced. Therefore, as described later, in order to remove the oxygen in the casing 21 when processing the wafer W, a vacuum atmosphere is formed in the casing 21. Here, as described above, the smaller molecular weight molecules generated by cutting the bonds by light irradiation are easily released as gases into this vacuum atmosphere. The gases generated by decomposition and crosslinking are generated regardless of the penetration range of the wavelength. The long-wavelength light reaches the deep part of the resist pattern 13, but before that, the crosslinking reaction caused by the short-wavelength light proceeds (takes precedence), and the change in the shape such as the height and width of the resist pattern 13 can be suppressed.

[0060] Return Figure 1 , the controller 100 of the substrate processing apparatus 1 controls the rotary support portion 25, the gas supply portion 30, the gas discharge portion 35, and the light irradiation mechanism 40. As Figure 4 illustrated, in the controller 100, as a functional configuration (hereinafter referred to as a "functional module"), it has an irradiation control unit 111, a gas supply control unit 112, an exhaust control unit 113, and an access control unit 114. The above functional modules are merely for convenience to divide the functions of the controller 100 into multiple modules, and it does not mean that the hardware constituting the controller 100 must be divided into such modules.

[0061] The irradiation control unit 111 controls the light irradiation mechanism 40 to irradiate VUV light at a desired time. For example, the irradiation control unit 111 controls the light irradiation mechanism 40 to turn on all the light sources 42 before the irradiation time. In addition, the irradiation control unit 111 controls the light irradiation mechanism 40 to turn off all the light sources 42 after the irradiation time ends.

[0062] The gas supply control unit 112 controls the valve 30b to supply an inert gas into the housing 21 through the through hole 21a. The exhaust control unit 113 controls the vacuum pump 35a to discharge the gas in the housing 21 to the outside through the through hole 21b.

[0063] The access control unit 115 controls the gate valve 23 to open and close the transfer port 22 in accordance with the operation of inputting the wafer W into the housing 21 and the operation of sending out the wafer W from the housing 21, and controls the rotary support portion 25 to switch the holding and releasing of the wafer W by the holding portion 26.

[0064] The controller 100 is composed of one or more control computers. For example, the controller 100 has the Figure 5 shown circuit 120. The circuit 120 has one or more processors 121, a memory 122, a storage 123, and an input / output port 124. The storage 123 has a computer-readable storage medium such as a hard disk, for example. The storage medium stores a program for causing the substrate processing apparatus 1 to perform the substrate processing steps described later. The storage medium can be a non-volatile 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 results of the processor 121. The processor 121 cooperates with the memory 122 to execute the above program, constituting the above respective functional modules. The input / output port 124 performs input and output of electrical signals between the respective parts controlled by the controller 100 in accordance with instructions from the processor 121.

[0065] In addition, the hardware configuration of the controller 100 is not necessarily limited to constituting each functional module by a program. For example, each functional module of the controller 100 can also be constituted by a dedicated logic circuit or an ASIC (Application Specific Integrated Circuit) obtained by integrating it.

[0066] [Substrate Processing Method]

[0067] Next, with reference to Figure 1 and Figure 6 , the operation (substrate processing method) of the substrate processing apparatus 1 will be described. Figure 6 is a diagram showing an outline of the change in the pressure inside the housing 21 over time. Figure 7 In the diagram, the horizontal axis represents the elapsed time during processing, and the vertical axis represents the pressure (unit: Pa) inside the housing 21, which is a processing container, and is schematically shown as a logarithmic axis approximately. First, with the operations of the gas supply unit 30 and the gas discharge unit 35 stopped, the wafer W is sent into the housing 21 by the transfer mechanism. When the wafer W is placed on the holding unit 26 of the rotary support unit 25, the gate valve 23 is closed to make the inside of the housing 21 airtight. At this time, the inside of the housing 21 becomes, for example, an atmospheric atmosphere of standard air pressure ( Figure 7 at the time t0). Then, by the operation of the gas discharge unit 35, the pressure inside the housing 21 is reduced.

[0068] Vacuum reduction is performed, and when the pressure inside the housing 21 becomes 1 Pa (time t1), the state at this time is maintained for a specified time. After temporarily maintaining the vacuum state of 1 Pa (time t2), the valve 30b of the gas supply unit 30 is opened to supply Ar gas into the housing 21. As a result, an Ar gas atmosphere is formed inside the housing 21, and the pressure inside the housing 21 rises. In addition, the vacuum reduction speed and the pressure increase speed can be controlled by the operations of the gas supply unit 30 and the gas discharge unit 35. Also, the vacuum reduction speed and the pressure increase speed can be constant or can be changed halfway.

[0069] When the pressure inside the housing 21 reaches 10,000 Pa due to the Ar gas, for example, light containing VUV light is irradiated onto the wafer W from the light source 42 while maintaining the pressure inside the housing 21 (time t3). When the light is irradiated from the light source 42 for a specified time, for example, 30 seconds, the light irradiation is stopped (time t4). After that, the operations of the gas supply unit 30 and the gas discharge unit 35 are stopped, and after the pressure inside the housing 21 returns to the atmospheric atmosphere, the wafer W is sent out from the housing 21. In this way, the processing of the wafer W by the substrate processing apparatus 1 is completed.

[0070] 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 unit 30 and the operation of discharging gas by the gas discharge unit 35 are also performed. Therefore, it can be said that the replacement of the Ar gas occurs while maintaining the pressure inside the housing 21.

[0071] In addition, during the period when light is irradiated from the light source 42 (between time t3 and time t4), the pressure inside the housing 21 can be constant or gradually changing. In Figure 6 the example shown, during the period when light is irradiated from the light source 42, in order to suppress outgassing from the surface of the wafer W, the pressure inside the housing 21 is set to 10,000 Pa. However, during the period when light is irradiated from the light source 42, the amount of outgassing generated gradually decreases. In this case, the pressure inside the housing 21 can also be controlled to gradually decrease. By adopting such a configuration, light can be irradiated to the wafer W in a state closer to vacuum.

[0072] [Regarding Substrate Processing Targeting ArF Immersion Lithography Resist Materials]

[0073] Here, in the substrate processing apparatus 1 of the present embodiment, the resist material for the resist pattern 13 is a material suitable for immersion lithography using an ArF laser (wavelength 193 nm) as an exposure light source. Regarding this case, the following findings are obtained. That is, it is found that by irradiating light containing the above-mentioned VUV light under specified conditions, the surface roughness of the resist pattern 13 can be improved, and the surface roughness of the pattern obtained by etching using the resist pattern 13 as a mask can also be improved. In the following embodiments, the improvement of the surface roughness in the case where the resist material can be used for materials for ArF immersion lithography is described.

[0074] As described above, the composition of the resist material suitable for ArF immersion lithography is adjusted so that it can be exposed with an ArF laser (wavelength 193 nm). Therefore, the optimal conditions for this process using VUV light are different from those of resist materials corresponding to other exposure wavelengths. This VUV light includes the 193 nm wavelength that is the same as the exposure wavelength of the resist material for ArF immersion lithography. Even for materials that can be exposed with light of other wavelengths included in the VUV light, the influence on the pattern changes depending on the wavelength of the light. Therefore, for each resist material corresponding to each exposure condition, it is necessary to study the optimal conditions. In addition, in the following embodiments, the case of using a general resist material for ArF immersion lithography is described. In addition, the resist material may also contain additives such as acid generators, solvents, decomposition products, and the like.

[0075] As described above, by irradiating light containing VUV light in the substrate processing apparatus 1, chemical bonds at each position in the molecules constituting the resist pattern 13 are broken in the wafer W, thereby generating various compounds. At this time, since the chemical bonds are broken at each position, the surface roughness of the resist pattern 13 is reduced. In addition, through the crosslinking reaction that occurs during and after the irradiation of light containing VUV light, the surface of the resist pattern 13 is cured, and as a result, the etching tolerance becomes higher. That is, by irradiating VUV light, the breaking of chemical bonds and the crosslinking reaction in the resist pattern 13 can be appropriately performed. Moreover, through the breaking of these chemical bonds and the crosslinking reaction, the surface roughness of the underlying film etched using the resist pattern 13 as a mask can be improved.

[0076] However, when either the breaking of chemical bonds or the crosslinking reaction in the resist pattern 13 is insufficient or excessive, the improvement effect of the above-mentioned surface roughness becomes low. In other words, by appropriately adjusting the irradiation level of light containing VUV light in the substrate processing apparatus 1, the improvement effect of the surface roughness can be enhanced. Regarding this point, the results of verification will be described below. In particular, the resist material for ArF immersion lithography has a high responsiveness to light from the light source 42 containing VUV light, and the improvement effect of the surface roughness varies depending on its intensity and the like. This will be explained.

[0077] As factors for changing the irradiation conditions when irradiating the resist pattern 13 with VUV light in the substrate processing apparatus 1, examples include "irradiation dose (cumulative irradiation dose)", "Ar flow rate during irradiation", "rotation speed of the wafer during irradiation", and "current compensation value (bias) of the light source". Among them, the "irradiation dose" corresponds to the total energy of the light (VUV light) emitted from the light source 42 to the resist pattern 13. In addition, the "Ar flow rate during irradiation" and the "current compensation value of the light source" are related to the transmissibility of the light emitted from the light source 42. That is, they affect the extent to which VUV light can reach the resist pattern 13. In addition, the "rotation speed of the wafer" affects the degree of modification effect that the VUV light emitted from the light source 42 can have on the resist pattern 13. Hereinafter, the results of evaluation by changing the conditions related to the above factors will be described.

[0078] (Evaluation of the change amount of line width)

[0079] (Evaluation test 1)

[0080] As Evaluation Test 1, the change in line width (CD: Critical Dimension) was evaluated under two conditions of changing the Ar flow rate when irradiating light from the light source 42. The objects of evaluation were the resist pattern 13 and the pattern in the underlying film when etching the underlying film using the resist pattern 13 as a mask.

[0081] First, as the wafer W to be evaluated, a wafer W having a resist pattern 13 formed on the SOC film 11 and the SOG film 12 was prepared. In addition, the pattern size of the wafer W was 45 nm.

[0082] In the housing 21 of the substrate processing apparatus 1, the wafer W having the resist pattern 13 formed on its surface 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. A series of operations was the same as the above-described substrate processing method. The irradiation amount was changed in 5 levels (25.1, 42.5, 75.2, 107.8, 149 these 5 levels) between 0 mj / cm 2 ~150 mj / cm 2 After that, the line width (CD) was measured for the resist pattern 13 and the pattern in the underlying film when etching the underlying film using the resist pattern 13 as a mask, respectively. In addition, regarding the rotation speed of the wafer at this time, the number of rotations of the wafer during the period of irradiating the wafer with a predetermined irradiation amount of light was set to 3, and the compensation value of the lamp (current compensation value of the light source) was set to 2.5. In the following embodiments, the resist pattern 13 is referred to as ADI (After Development Inspection), and the pattern in the underlying film is referred to as AEI (After Etch Inspection).

[0083] In Figure 7 the measurement results of the line width (CD) are shown for the case where the Ar flow rate when irradiating light from the light source 42 is 15 L / min and the case where it is 20 L / min, respectively. In Figure 7 the measurement results when the operation of irradiating light containing VUV light from the light source 42 using the substrate processing apparatus 1 is not performed are used as reference values, and the cases of how much the line width has changed with respect to the reference values are plotted in a graph, respectively.

[0084] (Evaluation Test 2)

[0085] As Evaluation Test 2, the change in the line width (CD) in the resist pattern 13 (ADI) and the underlying film pattern (AEI) was evaluated under three conditions of changing the rotation speed of the wafer when irradiating light from the light source 42.

[0086] Inside the housing 21 of the substrate processing apparatus 1, a wafer W having a resist pattern 13 formed on its surface is accommodated, and the inside of the housing 21 is depressurized. After the set pressure is reached inside the housing 21, light is irradiated with the light source 42. A series of operations is the same as the above-described substrate processing method. The irradiation amount is changed in three levels (the three levels of 25.1, 75.2, and 149) between 0 mj / cm 2 ~150 mj / cm 2 . After that, the line widths (CD) are measured for the resist pattern 13 (ADI) and the underlying film pattern (AEI), respectively. In addition, the Ar flow rate at this time is set to 20 L / min, and the lamp compensation value is set to 2.5.

[0087] In Figure 8 , regarding the rotation speed of the wafer when light is irradiated with the light source 42, the measurement results of the line width (CD) are shown respectively when the number of rotations of the wafer during the period of irradiating a prescribed amount of light is 1 turn, 3 turns, and 5 turns. In Figure 8 , taking the measurement results when the operation of irradiating light containing VUV light from the light source 42 using the substrate processing apparatus 1 is not performed as the reference value, the degree to which the line width changes with respect to the reference value is plotted separately in a graph.

[0088] (Evaluation Test 3)

[0089] As Evaluation Test 3, when the lamp current compensation value when irradiating light from the light source 42 is changed under two conditions, the changes in the line widths (CD) in the resist pattern 13 (ADI) and the underlying film pattern (AEI) are evaluated.

[0090] Inside the housing 21 of the substrate processing apparatus 1, a wafer W having a resist pattern 13 formed on its surface is accommodated, and the inside of the housing 21 is depressurized. After the set pressure is reached inside the housing 21, light is irradiated with the light source 42. A series of operations is the same as the above-described substrate processing method. The irradiation amount is changed in five levels (the five levels of 25.1, 42.5, 75.2, 107.8, and 149) between 0 mj / cm 2 ~150 mj / cm 2 . After that, the line widths (CD) are measured for the resist pattern 13 (ADI) and the underlying film pattern (AEI), respectively. In addition, the Ar flow rate at this time is set to 20 L / min, and the number of rotations of the wafer is set to 3.

[0091] In Figure 9 , for the cases where the lamp compensation value (current compensation value) in the light source 42 is 2.5 and 3.5, the measurement results of the line width (CD) are shown respectively. In Figure 9Among them, the measurement results when the substrate processing apparatus 1 is not used to irradiate light containing VUV light from the light source 42 are used as reference values, and the cases of how much the line width has changed with respect to the reference values are plotted separately in the graph.

[0092] (Results of Evaluation Tests 1 to 3)

[0093] In Figures 7 - 9 either case, regarding the line width of the resist pattern (ADI), the line width is the smallest near an irradiation dose of 50 mj / cm 2 and then gradually increases as the irradiation dose increases. In addition, regarding the line width of the etched pattern (AEI) of the underlying film, the line width is the smallest at an irradiation dose of 50 mj / cm 2 and then, as the irradiation dose increases, the line width is approximately constant.

[0094] In both the resist pattern (ADI) and the underlying film pattern (AEI), until the irradiation dose reaches around 50 mj / cm 2 , the line width gradually decreases, so the reaction in the resist pattern is insufficient (insufficient irradiation dose). On the other hand, when the irradiation dose exceeds 50 mj / cm 2 , the line width of the resist pattern (ADI) increases, but the line width of the underlying film pattern (AEI) does not change. Based on the above, it can be inferred that: at an irradiation dose of 50 mj / cm 2 , the bond cleavage and crosslinking reactions in the resist pattern 13 are sufficiently carried out to a certain extent, and as a result, the etching resistance of the resist pattern 13 is in an improved state. Therefore, even if the irradiation dose is changed, the line width of the underlying film pattern (AEI) can be kept approximately constant to a certain extent. However, regarding the resist pattern 13, a result of an increase in the line width can be obtained when the irradiation dose starts to increase from 50 mj / cm 2 . Based on the above, it is considered that when the irradiation dose starts to increase from 50 mj / cm 2 , the chemical bonds are cut excessively compared to the crosslinking reaction and the resist pattern 13 becomes a so-called blurred state. Based on the above, by setting the irradiation dose to 50 mj / cm 2 , the reaction caused by irradiating VUV light in the resist pattern (ADI) can be appropriately carried out.

[0095] In addition, Figure 7 the line width of the underlying film pattern (AEI) under the condition that Ar is 20 mL / min is smaller than the line width of the underlying film pattern (AEI) under the condition that Ar is 15 mL / min. In addition, Figure 9The line width of the lower layer film pattern (AEI) under the condition that the lamp compensation value is 3.5 is smaller than that of the lower layer film pattern (AEI) under the condition that the lamp compensation value is 2.5. This is because, due to the excessive reaction in the resist pattern 13 by irradiating light from the light source 42, the etching tolerance in the resist pattern 13 is reduced.

[0096] As described above, both the Ar flow rate and the lamp compensation value are values related to the transmittance of the light emitted from the light source 42. For example, the Ar flow rate is the flow rate of Ar supplied into the housing 21 while maintaining a prescribed pressure inside the housing 21 during the irradiation of light. Therefore, when the flow rate of Ar increases, the amount of gas discharged from the housing 21 to the outside also increases, and thus it is also possible to promote the discharge of impurities (such as sublimates) generated inside the housing 21 to the outside. Conversely, when the flow rate of Ar decreases, the impurities generated inside the housing 21 tend to remain inside the housing 21. As a result, a part of the light emitted from the light source 42 is absorbed or diffused by the impurities or the like. Consequently, there is a possibility that the spectrum of the light irradiated onto the wafer W changes with respect to the light from the light source 42. As described above, the Ar flow rate is a factor that can affect the transmittance and wavelength characteristics of the light emitted from the light source 42.

[0097] In addition, the lamp compensation value is a value related to the intensity of the light emitted from the light source 42. When the compensation value is increased, the intensity of the light from the light source 42 becomes larger, and the amount of light reaching the resist pattern 13 becomes larger. As described above, in either the case where the Ar flow rate is increased or the case where the lamp compensation value is increased, the amount of light reaching the resist pattern 13 becomes larger. 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. In addition, regardless of the condition of irradiating the resist pattern 13 with light of the same irradiation amount, when the Ar flow rate or the lamp compensation value becomes larger, the line width of the resist pattern 13 (ADI) does not change. In contrast, it changes in such a way that the line width of the lower layer film pattern (AEI) becomes smaller. Based on the above, it can be speculated that the function of the upper resist pattern 13 as a mask during etching is reduced.

[0098] (Evaluation of the improvement of surface roughness)

[0099] (Evaluation test 4)

[0100] As Evaluation test 4, when the Ar flow rate during the irradiation of light from the light source 42 was changed under two conditions, the change in the LWR of the pattern in the lower layer film during the etching of the lower layer film using the resist pattern 13 as a mask was evaluated. LWR (line wideth roughness) is an index of the roughness of the pattern, and the smaller the value, the smaller the surface roughness of the pattern.

[0101] As an evaluation object, a wafer W having a resist pattern 13 formed on a SOC film 11 and a SOG film 12 was prepared. In addition, the pattern size of the wafer W was made 45 nm.

[0102] In the housing 21 of the substrate processing apparatus 1, the wafer W having the resist pattern 13 formed on its surface 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. A series of operations was the same as the above-described substrate processing method. The irradiation amount was changed in 5 levels (25.1, 42.5, 75.2, 107.8, 149 these 5 levels) between 0 mj / cm 2 ~150 mj / cm 2 After that, the LWR was measured for the resist pattern 13 (ADI) and the pattern (AEI) in the underlying film when the underlying film was etched using the resist pattern 13 as a mask, respectively. In addition, regarding the rotational speed of the wafer at this time, the rotational speed of the wafer during the period when light of a specified irradiation amount was irradiated to the wafer was made 3, and the compensation value of the lamp was made 2.5.

[0103] In Figure 10 the measurement results of the LWR are shown for the case where the Ar flow rate is 15 L / min and the case where it is 20 L / min when light is irradiated with the light source 42. In Figure 10 the measurement results when the operation of irradiating light containing VUV light from the light source 42 using the substrate processing apparatus 1 is not performed are used as reference values, and the degree to which the surface roughness is improved with respect to the reference values is calculated and shown as a bar graph as the improvement rate. The improvement rate is calculated using the mathematical formula of (LWR under each condition - reference value) / (reference value)×100 (%).

[0104] (Evaluation Test 5)

[0105] As Evaluation Test 5, the change in the LWR in the resist pattern 13 (ADI) and the underlying film pattern (AEI) was evaluated when the rotational speed of the wafer when light was irradiated from the light source 42 was changed under 3 conditions.

[0106] In the housing 21 of the substrate processing apparatus 1, the wafer W having the resist pattern 13 formed on its surface 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. A series of operations was the same as the above-described substrate processing method. The irradiation amount was changed in 3 levels (25.1, 75.2, 149 these 3 levels) between 0 mj / cm 2 ~150 mj / cm 2 After that, the LWR was measured for the resist pattern 13 (ADI) and the underlying film pattern (AEI), respectively. In addition, the Ar flow rate at this time was made 20 L / min, and the compensation value of the lamp was made 2.5.

[0107] In Figure 11 with respect to the rotational speed of the wafer when irradiated with light from the light source 42, the measurement results of LWR are shown respectively when the number of rotations of the wafer during the period of irradiating a specified amount of light is 1, 3, and 5 turns. In Figure 11 the measurement results when the operation of irradiating light containing VUV light from the light source 42 using the substrate processing apparatus 1 is not performed are used as reference values, and the improvement rates indicating how much the LWR has changed with respect to the reference values are calculated and shown as bar graphs respectively.

[0108] (Evaluation Test 6)

[0109] As Evaluation Test 6, the changes in LWR in the resist pattern 13 (ADI) and the underlying film pattern (AEI) were evaluated when the current compensation value of the lamp when irradiating light from the light source 42 was changed under two conditions.

[0110] In the housing 21 of the substrate processing apparatus 1, a wafer W having a resist pattern 13 formed on its surface is accommodated, and the inside of the housing 21 is depressurized. After the set pressure is reached inside the housing 21, light is irradiated with the light source 42. A series of operations is the same as the above-described substrate processing method. The irradiation amount is changed in 5 levels (25.1, 42.5, 75.2, 107.8, 149 these 5 levels) between 0 mj / cm 2 ~150 mj / cm 2 . Thereafter, the line widths (CD) of the resist pattern 13 (ADI) and the underlying film pattern (AEI) are measured respectively. In addition, the Ar flow rate at this time is set to 20 L / min, and the number of rotations of the wafer is set to 3.

[0111] In Figure 12 the measurement results of the line width (CD) are shown respectively for the cases where the compensation value (current compensation value) of the lamp in the light source 42 is 2.5 and 3.5. In Figure 12 the measurement results when the operation of irradiating light containing VUV light from the light source 42 using the substrate processing apparatus 1 is not performed are used as reference values, and the improvement rates indicating how much the LWR has changed with respect to the reference values are calculated and shown as bar graphs respectively.

[0112] (Results of Evaluation Tests 4 - 6)

[0113] In Figures 10 - 12 either case, when the irradiation amount becomes larger than 50 mj / cm 2 , the LWR of the underlying film pattern (AEI) is improved significantly. As described above, by irradiating with an irradiation amount of 50 mj / cm 2Light of a certain level (VUV light) can modify the resist pattern 13 to sufficiently improve the surface roughness of the underlying film pattern (AEI). This is because it has a tendency roughly the same as the results of the line width evaluation tests 1 to 3. In addition, when the irradiation amount becomes larger than 75 mj / cm 2 the improvement rate of LWR stabilizes.

[0114] In addition, based on the results of evaluation tests 1 to 3, the possibility of a decrease in the etching tolerance in the resist pattern 13 when Ar is 20 mL / min or the lamp compensation value is 3.5 was explained, and based on the results of evaluation tests 4 to 6, the same conclusion can also be drawn. That is, the following tendency was shown: Figure 7 the improvement rate of LWR of the underlying film pattern (AEI) under the condition that Ar in is 20 mL / min is smaller than that of the underlying film pattern (AEI) under the condition that Ar is 15 mL / min. In addition, the following tendency was shown: Figure 9 the improvement rate of LWR of the underlying film pattern (AEI) under the condition that the lamp compensation value in is 3.5 is smaller than that of the underlying film pattern (AEI) under the condition that the lamp compensation value is 2.5.

[0115] (Regarding the change in the irradiation effect of light caused by the rotation of the wafer)

[0116] In addition, based on Figure 11 the results shown, the following tendency can be obtained: when irradiating light containing VUV light from the light source 42, the influence of the rotation speed of the wafer W on the improvement rate of LWR is relatively slight, but the greater the rotation speed, the greater the improvement rate of LWR. As the reason for showing this tendency, when irradiating the same irradiation amount of light (VUV light) onto the resist pattern 13, the tendency of intrusion into the resist pattern 13 changes according to the rotation speed.

[0117] Figure 13 is a diagram for explaining the change in the intensity of light received at a specific position on the wafer W according to the change in the relative position between the specific position on the wafer W and the light source 42 when the wafer W rotates. Figure 13 The (a) of is a diagram showing the irradiation range of the light from the light source 42. Figure 13 The irradiation position C0 shown in the (a) of corresponds to the position (directly below) of the point light source 44 in the light source 42, and the intensity of the light from the light source 42 is the largest. On the other hand, the intensity of the light becomes smaller as it moves away from the irradiation position C0 corresponding to the point light source 44, and the intensity of the light is the smallest at the irradiation position C1 at the end. As described above, according to the positional relationship between the specific position on the wafer W and the light source 42, the amount of light at this position changes greatly. Therefore, an attempt is made in the substrate processing apparatus 1 to make the amount of light received at each position on the surface of the wafer W uniform to a certain extent by rotating the wafer W.

[0118] In Figure 13 (b) thereof, the movement of a specific point (hereinafter referred to as the specific point) of the wafer W relative to the light source 42 when the wafer W is rotated is schematically indicated by an arrow R1. In Figure 13 (b) thereof, a state is shown in which four light sources 42 are arranged at positions corresponding to the irradiation position C0. By rotating the wafer W, the specific point on the wafer W rotates along the arrow R1. At this time, the wafer W passes through two irradiation positions C0 and four irradiation positions C1. As described above, the irradiation position C0 is the position where the intensity of the light from the light source 42 is the maximum, and the irradiation position C1 is the position where the intensity of the light from the light source 42 is the minimum. That is, when the specific point on the wafer W moves (rotates) along the arrow R1, the intensity of the light received by the specific point changes corresponding to the operations of passing through the two positions of the irradiation position C0 and the irradiation position C1. Figure 13 (c) of Figure 13 and (d) of Figure 13 are diagrams schematically showing the change in the intensity of the light received by the specific point on the wafer W moving along the arrow R1. Figure 13 In the example shown in (d) of

[0119] compared with (c) of Figure 13 , the rotational speed is increased. When the rotational speed is increased, the movement path of the specific point (corresponding to the arrow R1) does not change, so the specific point passes through the two positions of the irradiation positions C0 and C1. However, when the rotational speed is high, the speed of change in the intensity of the light received by the specific point also becomes large. Figure 13 In a state where the intensity of the light is relatively high (for example, the irradiation position C0 in

[0120] etc.), among the light from the light source 42, light in a band with a relatively high intensity and light in a band with a relatively low intensity in the VUV light both become likely to penetrate into the resist pattern 13. On the other hand, in a state where the intensity of the light is relatively low (for example, the irradiation position C1 in Figure 13The state in which the state where the intensity of the light irradiated to a specific point is large as shown in (d) is repeated several times. By adopting such a configuration, each component corresponding to the continuous spectrum of the VUV light going to the resist pattern 13 can appropriately penetrate to a desired position (penetration depth corresponding to light of each wavelength) of the resist pattern 13. Therefore, as shown in the result of Figure 12 , there is a tendency that the improvement rate of LWR becomes larger by increasing the rotation speed. In addition, as a specific rotation speed, for example, it can be exemplified that the wafer W is rotated 3 to 12 times during the irradiation of light with an irradiation amount of 50 mj / cm 2 . This value corresponds to, for example, when the illuminance from the light source 42 is 0.8 mW / cm 2 , the required time necessary for one treatment is 63 seconds, and thus the rotation speed of the holding unit 26 is about 2 rpm to 12 rpm.

[0121] In addition, the rotation speed of the wafer W may not be constant during the irradiation of light from the light source 42. As described above, when the rotation speed becomes larger, the light in the band with a larger intensity in the VUV light becomes more likely to penetrate the resist pattern 13. Therefore, by irradiating the wafer W with the light from the light source 42 while changing the rotation speed, it is also possible to adjust the irradiation of the light from the light source 42 so that the light in a specific band becomes more likely to penetrate the wafer W.

[0122] In addition, when a circular substrate such as the wafer W is rotated at a certain angular velocity, the moving speeds with respect to the light source 42 are different inside (near the center) and outside (near the end) of the wafer W, so the positional relationship between the wafer W and the light source 42 during rotation is very different. Specifically, when the distance from the rotation center increases, the substantial moving speed increases. Therefore, the moving speed of the inside of the wafer W with respect to the light source 42 becomes smaller, and the moving speed of the outside of the wafer W with respect to the light source 42 becomes larger. In addition, the irradiation areas passed through during one rotation of the wafer W are very different inside and outside the wafer W. For example, in the case where the light source 42 is arranged as Figure 3 , inside the wafer W, the irradiation areas of the 4 light sources 42 inside pass during one rotation of the wafer W. On the other hand, outside the wafer W, the irradiation areas of the 8 light sources 42 outside pass during one rotation of the wafer W. Therefore, the more outside the wafer W, the more irradiation areas of the light source 42 are passed through, and the number of times passing through the area with a larger light intensity increases. In this way, even when the wafer W rotates at a certain speed, depending on the position of the wafer W (especially, the distance from the rotation center), the light received by the resist pattern 13 on the surface of the wafer W (especially, the speed of change in the intensity of the irradiated light) may sometimes be different. Therefore, as a result, the improvement degree of the surface roughness of the resist pattern 13 is different based on the position on the surface of the wafer W. In addition, inFigure 3 In the case of the configuration shown, outside the wafer W, the period during which the wafer passes through a region with a relatively high light intensity of the light source 42 is longer, and the period during which the wafer passes through one of the regions with a low light intensity is shorter. Therefore, the wafer W is more strongly affected by the period during which it passes through the region with a relatively high light intensity of the light source 42, and thus, the light-induced modification in the resist pattern 13 can be promoted.

[0123] In Figure 14 , an example of the illuminance distribution (distribution of the amount of light irradiation) of the light received at each position of the wafer W when light is irradiated from a plurality of light sources 42 while the wafer W is being rotated is shown. Here, the light sources 42 are arranged as Figure 3 shown, with a plurality of light sources 42 arranged inside and outside. In Figure 14 the example shown, it was confirmed that a deviation in the illuminance of the light received on the surface of the wafer W occurred between the outside and the inside of the wafer W. Specifically, in the outer region W1 of the wafer W, the received illuminance of the light was moderate, whereas in the inner region W2 of the wafer W, the received illuminance of the light became lower (the region W2 was the color on the Min. side). In addition, near the center, there was also a region where the illuminance changed according to the distance from the center between the region W1 and the region W2. As the cause of such a deviation in the illuminance of the light, as described above, the reason that the moving speed of the wafer W relative to the light source 42 varies depending on the position of the wafer W can be cited. In addition, the manner in which the regions with a relatively high intensity (e.g., the irradiation position C0 in Figure 13 ) and the regions with a relatively low intensity (e.g., the irradiation position C1 in Figure 13 ) in the irradiation regions of the respective light sources 42 vary based on each position of the wafer W can also be a cause. Such a deviation in the illuminance distribution also affects the deviation in the improvement effect of the roughness of the resist pattern 13 and the surface of the underlying film pattern.

[0124] When a deviation in the illuminance distribution occurs at each position on the surface of the wafer W (especially in the radial direction), as a method for improving this situation, changing the intensity of the light irradiated from the plurality of light sources 42 to the wafer W is considered.

[0125] The specific method of varying the intensity of the light irradiated from the light source 42 to the wafer W based on the position of the wafer W (especially inside and outside) is not particularly limited. For example, considering changing 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, etc. For example, by making Figure 3Among the 12 light sources 42 shown, the current compensation value of the 4 inner light sources is 3.5, and the current compensation value of the 8 outer light sources is 2.5, which can make the intensity of the light output from the inner light sources 42 greater than the intensity of the light from the outer light sources. In addition, without changing the current compensation value or the like, but by changing the configuration of the light sources or the like, it is also possible to reduce the deviation of the illuminance distribution as shown in Figure 14 As described above, the light output from the light source 42 has a large difference in intensity near the center (C0) and near the end (C1) in the irradiation area. In addition, near the center (C0) and near the end (C1), the degree to which the light reaches the deep layer in the resist pattern 13 when passing through this area and the degree of modification of the resist pattern 13 based on the received light are quite different. And for adjacent light sources 42, by arranging them close to each other in such a way that the ends of the irradiation areas overlap, the amount of light received by the wafer W when passing through the overlapping area can be increased. Therefore, by adjusting the size of the overlapping area or the like, it is also possible to adjust the amount of light received by the resist pattern 13. As described above, in particular, by changing various components related to the light source 42, a configuration can be achieved in which the intensity of the light irradiated from the light source 42 to the wafer W is different based on the position of the wafer W (especially the inner and outer sides).

[0126] In addition, the "inner side" and "outer side" of the wafer W represent a relative positional relationship. Therefore, there is no particular limitation on where the boundary between the inner side and the outer side is. Based on the number and configuration of the light sources 42, the position where the deviation of the illuminance distribution along the radial direction of the wafer W occurs can be changed. However, since the light is irradiated from the light source 42 while the wafer W is rotated, the moving speed of the wafer W is smaller on the inner side and larger on the outer side. Therefore, it is more likely that the inner side of the wafer W is less likely to receive sufficient light for the modification (bond breaking and crosslinking reaction) of the resist pattern 13 compared to the outer side of the wafer W. Considering this point, a configuration in which the intensity of the light irradiated from the light source 42 to the wafer W is different on the inner and outer sides of the wafer W can be adopted.

[0127] In addition, even for a material with high responsiveness to light from the light source 42, such as the resist material for ArF immersion lithography described above, there is a possibility that the modification of the resist pattern 13 (bond cleavage and surface crosslinking reaction) cannot be sufficiently performed when the film thickness of the resist film is large. As described above, the component of light with a wavelength shorter than 160 nm, which is important for promoting the crosslinking reaction near the surface of the resist pattern 13, is difficult to reach the deep layer. Therefore, when the film thickness of the resist film forming the resist pattern 13 increases, there is a possibility that the progress of modification varies depending on the position of the resist pattern 13. Specifically, even if the modification is sufficiently performed using the light from the light source 42 above and the etching tolerance becomes high, there is a possibility that the modification cannot be sufficiently performed below the resist pattern 13 (the side closer to the underlying film) and the etching tolerance cannot be increased. It was confirmed that the component of light with a wavelength shorter than 160 nm penetrates only about 50 nm from the surface of the resist pattern 13. Therefore, the effect of improving the surface roughness obtained by modifying the resist pattern 13 with the above-mentioned VUV light is particularly significant when the film thickness of the resist (the height of the resist pattern 13) is smaller than 50 nm.

[0128] [Function]

[0129] As described above, in the substrate processing apparatus 1 and the substrate processing method described above, it is possible to make the irradiation amount of light irradiated to the inner side of the substrate larger than the irradiation amount of light irradiated to the outer side of the substrate. Therefore, it is possible to increase the irradiation amount of light to the inner side of the substrate and improve the effect of improving the surface roughness. As described above, in a substrate having a pattern formed on the surface thereof and composed of a resist material for ArF immersion lithography, the degree of improvement in the surface roughness of the pattern easily varies depending on the irradiation amount of light. In addition, when irradiating light while rotating the substrate, the moving speed of the substrate becomes slower toward the inner side, so the irradiation amount of light becomes smaller. In contrast, by adopting the above configuration, it is possible to increase the amount of light received by the pattern formed of the resist material on the substrate surface, and in particular, to improve the effect of improving the surface roughness of the inner side.

[0130] In addition, in the substrate processing apparatus 1, it may be configured such that the output intensity of the light source 42 that irradiates light to the inner side of the substrate is larger than the output intensity of the light source 42 that irradiates light to the outer side of the substrate. In this case, by increasing the output intensity of the light source 42 so that the irradiation amount of light irradiated to the inner side of the substrate is larger than the irradiation amount of light irradiated to the outer side of the substrate, it is possible to more simply adjust the irradiation amount of light between the inner side and the outer side of the substrate. In addition, it may be configured to limit the adjustment of the above output intensity during a part of the period when the substrate is irradiated with light. For example, at the beginning and the end of the irradiation, the output of the light source corresponding to the outer side of the substrate may be reduced, or the output of the light source corresponding to the inner side of the substrate may be increased.

[0131] In addition, as described above, instead of making the output intensity of the light source 42 that irradiates the inner side of the substrate larger than the output intensity of the light source 42 that irradiates the outer side of the substrate, the irradiation times can be made different from each other. That is, it can also be configured such that the irradiation amount of the light irradiated to the inner side of the substrate is made larger than the irradiation amount of the light irradiated to the outer side of the substrate by making the time for the light source 42 to irradiate light different between the inner side and the outer side of the substrate. For example, before the light source 42 that irradiates the outer side of the substrate, the light source 42 that irradiates the inner side of the substrate can be used for irradiation. In addition, after stopping the irradiation of light from the light source 42 that irradiates the outer side of the substrate, the irradiation of light from the light source 42 that irradiates the inner side of the substrate can be stopped. As described above, the irradiation amount of the light irradiated to the inner side of the substrate can also be made larger than the irradiation amount of the light irradiated to the outer side of the substrate by making the irradiation time of the light source 42 that irradiates the inner side of the substrate longer than the irradiation time of the light source 42 that irradiates the outer side of the substrate. It is also possible to make the irradiation amount of the light irradiated to the inner side of the substrate larger than the irradiation amount of the light irradiated to the outer side of the substrate by combining the adjustment of the output intensity and the adjustment of the irradiation time described in the above-described embodiment. In this case, it is also possible to make the irradiation amount of the light irradiated to the inner side of the substrate larger than the irradiation amount of the light irradiated to the outer side of the substrate while making the irradiation time of the light source 42 that irradiates the inner side of the substrate shorter than the irradiation time of the light source 42 that irradiates the outer side of the substrate.

[0132] In addition, it includes a gas supply unit 30 that supplies an inert gas into the processing container and a gas discharge unit 35 that discharges gas from the processing container. At this time, the gas supply unit 30 and the gas discharge unit 35 can be made into a state where, during the period when the light source unit irradiates light, the supply and discharge of gas are performed while changing the pressure inside the processing container. By adopting such a configuration, it is possible to irradiate vacuum ultraviolet light to the pattern while making the pressure inside the processing container a state corresponding to the surface condition of the substrate.

[0133] As described above, various exemplified embodiments have been described, but it is not limited to the above-exemplified embodiments, and various omissions, substitutions, and changes can be made. In addition, elements in different embodiments can be combined to form other embodiments.

[0134] For example, the arrangement and number of the light sources 42 in the substrate processing apparatus 1 can be appropriately changed. In addition, components for controlling the path of the light emitted from the light source 42 can be added. In addition, the arrangement and configuration of each part inside the substrate processing apparatus 1 can be appropriately changed. In addition, the pressure control and the like described in the above-described embodiment are only examples, and the pressure control inside the housing 21 can also be changed to be performed at a stage before the light is irradiated from the light source 42.

[0135] In accordance with the above description, various embodiments of the present invention have been described in the specification for illustrative purposes, and it should be understood that various changes can be made without departing from the scope and gist of the present invention. Therefore, the various embodiments disclosed in this specification are not restrictive, and the true scope and gist are given by the scope of the appended claims.

Claims

1. A substrate processing device, characterized in that: include: a holding portion for holding a substrate in a processing container, wherein the substrate has a pattern formed on a surface of a resist material for ArF immersion lithography; a rotation driving portion that rotates the holding portion; and a light source unit having a plurality of light sources, which irradiates light including vacuum ultraviolet light to the surface of the substrate held by the holding unit rotated by the rotation drive unit, Each of the plurality of light sources emits light having an illumination range emitted from a point light source within the light source. The plurality of light sources are arranged so that, when the substrate rotates, the outer side of the substrate passes through more illumination areas of the light sources than the inner side of the substrate. When the light source unit irradiates light while rotating the substrate by the rotation driving unit, the amount of light irradiated from the light source unit to the inner side of the substrate is greater than the amount of light irradiated from the light source unit to the outer side of the substrate, thereby increasing the amount of light irradiated to the inner side of the substrate whose moving speed is slower than that of the outer side of the substrate. The vacuum ultraviolet light is a continuous spectrum light, including light with a wavelength longer than 160 nm and light with a wavelength shorter than 160 nm.

2. The substrate processing device according to claim 1, characterized in that: The output intensity of the light source for irradiating light to the inner side of the substrate is made greater than the output intensity of the light source for irradiating light to the outer side of the substrate.

3. The substrate processing device according to claim 1 or 2, characterized in that: The time for irradiating the inner side of the substrate with light and the time for irradiating the outer side of the substrate with light are made different from each other.

4. The substrate processing device according to claim 1 or 2, characterized in that: comprising a gas supply unit for supplying an inert gas into the processing container and a gas exhaust unit for exhausting the gas from the processing container, The gas supply unit and the gas exhaust unit supply and exhaust the gas while changing the pressure in the processing container during light irradiation by the light source unit.

5. A substrate processing method, comprising: irradiating a surface of the substrate with light including vacuum ultraviolet light from a light source unit having a plurality of light sources while rotating the substrate in a processing container, wherein the substrate has a pattern formed on the surface thereof made of a resist material for ArF immersion lithography, The substrate processing method is characterized in that: Each of the plurality of light sources emits light having an illumination range emitted from a point light source within the light source. The plurality of light sources are arranged so that, when the substrate rotates, the outer side of the substrate passes through more illumination areas of the light sources than the inner side of the substrate. The substrate processing method makes the amount of light irradiated from the light source portion to the inner side of the substrate greater than the amount of light irradiated from the light source portion to the outer side of the substrate when the substrate is rotated and irradiated with the light, thereby increasing the amount of light irradiated to the inner side of the substrate whose moving speed is slower than that of the outer side of the substrate. The vacuum ultraviolet light is a continuous spectrum light, including light with a wavelength longer than 160 nm and light with a wavelength shorter than 160 nm.

6. A computer-readable storage medium, characterized in that: A program for causing the apparatus to execute the substrate processing method according to claim 5 is stored.

Images