JP2026011350A - Exposure method, exposure apparatus, and article manufacturing method - Google Patents

Abstract

A technique advantageous for suppressing the overcorrection phenomenon of exposure astigmatism is provided.
[Solution] An exposure method for exposing a substrate includes an adjustment step of irradiating light onto an optical element included in a projection optical system while at least a portion of the light beam is blocked by a shield to adjust the optical characteristics of the projection optical system, a heat dissipation step of releasing heat accumulated in the shield by the adjustment step, and an exposure step of exposing the substrate via the projection optical system after the heat dissipation step, wherein heat is dissipated from the shield at an amount based on at least one of the light irradiation conditions in the adjustment step and the exposure conditions in the exposure step.
[Selected Figure] Figure 1

Description

The present invention relates to an exposure method, an exposure apparatus, and an article manufacturing method.

In the manufacture of semiconductor devices and other products, exposure apparatuses are used to illuminate an original (reticle or mask) with an illumination optical system and project the original pattern onto a substrate via a projection optical system, thereby exposing the substrate. Because the imaging characteristics of the projection optical system fluctuate depending on the exposure light, exposure apparatuses correct these imaging characteristics by controlling the position and orientation of optical elements. However, only a limited number of aberration components can be corrected by controlling the position and orientation of optical elements, making it difficult to correct non-rotationally symmetric imaging characteristics such as astigmatism. In particular, scanning exposure apparatuses (scanners) use a rectangular slit, which generates a non-rotationally symmetric heat distribution in the projection optical system during exposure, resulting in non-rotationally symmetric exposure aberrations (hereinafter referred to as "exposure astigmatism"). Furthermore, repeated exposures using originals containing many patterns in a specific direction can also result in significant exposure astigmatism.

Patent Document 1 discloses performing a dummy exposure to correct exposure astigmatism that occurs during actual exposure. When performing a dummy exposure, a light-shielding object within the projection optical system is used to block light from reaching the image plane. This is to prevent the stage on which the substrate is mounted from expanding due to exposure heat, which could affect exposure accuracy, and to prevent the resist applied to the substrate from being exposed to light. Furthermore, when light hits the light-shielding object, the object accumulates heat, which warms the nearby lens. Therefore, by placing such a light-shielding object, the efficiency of exposure astigmatism correction can be improved.

On the other hand, if heat remains in the light shield when switching to pattern exposure, when pattern exposure is performed with part of the light blocked by the shield, the residual heat will continue to cause aberrations, resulting in overcorrection. As disclosed in Patent Document 2, heat from the NA stop can be dissipated by radiation by adjusting the aperture shape. Another way to suppress overcorrection is to bring the light shield into contact with a low-temperature material to dissipate heat through heat transfer.

Japanese Patent Application Laid-Open No. 2022-185871 Japanese Patent Application Laid-Open No. 2005-044560

However, even if heat is dissipated through thermal conduction, depending on the exposure conditions and the duration of the dummy exposure, heat dissipation may be insufficient, resulting in overcorrection.

The present invention provides technology that is advantageous in suppressing the phenomenon of overcorrection of exposure astigmatism.

According to one aspect of the present invention, there is provided an exposure method for exposing a substrate, comprising: an adjustment step of irradiating optical elements included in a projection optical system with light while blocking at least a portion of the light beam with a shield to adjust the optical characteristics of the projection optical system; a heat dissipation step of dissipating heat accumulated in the shield by the adjustment step; and an exposure step of exposing the substrate via the projection optical system after the heat dissipation step, wherein in the heat dissipation step, heat is dissipated from the shield at an amount based on at least one of the light irradiation conditions in the adjustment step and the exposure conditions in the exposure step.

The present invention provides technology that is advantageous in suppressing the overcorrection phenomenon of exposure astigmatism.

FIG. 1 is a diagram showing the configuration of an exposure apparatus. 10 is a flowchart showing an exposure method. FIG. 10 is a diagram showing a rotationally asymmetric effective light source distribution used for dummy exposure. 10A and 10B are diagrams showing non-rotationally symmetric wavefront aberrations that occur in a projection optical system due to dummy exposure. 10 is a flowchart showing a heat dissipation process. 10 is a graph showing temperature change characteristics when the NA aperture is fully open. 10A to 10C are diagrams for explaining the operation of the NA diaphragm in the adjustment process and the heat dissipation process. FIG. 10 is a cross-sectional view of a main part of an NA diaphragm according to a modified example.

The following describes the embodiments in detail with reference to the attached drawings. Note that the following embodiments do not limit the scope of the claimed invention. While the embodiments describe multiple features, not all of these features are necessarily essential to the invention, and multiple features may be combined in any desired manner. Furthermore, in the attached drawings, the same reference numbers are used to designate identical or similar components, and redundant explanations will be omitted.

Figure 1 is a diagram showing the configuration of an exposure apparatus in an embodiment. In this specification and drawings, directions are indicated in an XYZ coordinate system, with the horizontal plane being the XY plane. The substrate 115, which is the object to be exposed, is placed on the substrate stage 102 so that its surface is parallel to the horizontal plane (XY plane). Therefore, hereinafter, the directions that are perpendicular to each other in a plane along the substrate placement surface of the substrate stage 102 are referred to as the X-axis and Y-axis, and the direction perpendicular to the X-axis and Y-axis is referred to as the Z-axis. Furthermore, hereinafter, the directions parallel to the X-axis, Y-axis, and Z-axis in the XYZ coordinate system are referred to as the X-direction, Y-direction, and Z-direction, respectively, and the directions of rotation around the X-axis, Y-axis, and Z-axis are referred to as the θX-direction, θY-direction, and θZ-direction, respectively.

Figure 1 shows the schematic configuration of an exposure apparatus in this embodiment. The exposure apparatus is configured to irradiate an original (also called a mask or reticle) 109 with light emitted from a light source 1 through an illumination optical system 104, and to project the pattern of the original onto a substrate 115 via a projection optical system 110, thereby exposing the substrate 115.

The illumination optical system 104 is composed of elements arranged in the optical path from the light source 1 to the original 109. The light source 1 can be, for example, an ArF excimer laser with an oscillation wavelength of approximately 193 nm or a KrF excimer laser with an oscillation wavelength of approximately 248 nm, but the present invention is not limited to a specific type of light source or wavelength of light.

Light emitted from the light source 1 enters the illumination system 104 and is guided to the diffractive optical element 3 by the deflection optical system 2. Typically, a diffractive optical element is mounted in each slot of a turret having multiple slots, and any diffractive optical element (e.g., diffractive optical element 4) can be positioned in the optical path by the drive mechanism 107.

Light emitted from the diffractive optical element 3 is focused by the condenser lens 5, forming a diffraction pattern on the diffraction pattern surface 6. The shape of the diffraction pattern can be changed by replacing the diffractive optical element 3 positioned in the light path using the drive mechanism 107.

The diffraction pattern formed on the diffraction pattern surface 6 is incident on the mirror 9 after parameters such as the annular ratio and σ value are adjusted by the prism group 7 and zoom lens 8. The light beam reflected by the mirror 9 is incident on the optical integrator 10. The optical integrator 10 can be configured, for example, as a lens array (fly's eye). The prism group 7 includes, for example, prisms 7a and 7b. If the distance between prisms 7a and 7b is sufficiently small, prisms 7a and 7b can be considered to be an integrated single glass plate. By changing the distance between prisms 7a and 7b, the annular ratio (ratio of outer diameter to inner diameter) and other parameters can be appropriately changed, thereby changing the light intensity distribution.

As shown in Figure 3, the diffraction pattern formed on the diffraction pattern surface 6 can be enlarged or reduced by the zoom lens 8 while maintaining a substantially similar shape. Light transmitted through the zoom lens 8 is imaged on the incident surface of the optical integrator 10. The optical integrator 10 is composed of multiple microlenses arranged two-dimensionally, and the light beam incident on the optical integrator 10 is split, with a light source being formed on the rear focal plane of each microlens. In this way, a substantial surface light source (secondary light source) with a light intensity distribution substantially identical to that of the incident light beam is formed on the rear focal plane of the optical integrator 10.

The light beam emitted from the optical integrator 10 has its light intensity distribution adjusted by the aperture stop 12 and is focused by the condenser lens 11 to superimpose and illuminate a field stop 13 positioned conjugate to the original 109. The field stop 13 defines the illumination area of the original 109 (and further the substrate 115) by the exposure light. The aperture shape of the aperture stop 12 can be set to any shape by driving the light-shielding plate that forms the aperture stop 12 with the drive mechanism 106. The numerical aperture NA of the illumination optical system 104 can be controlled by changing the aperture diameter of the aperture stop 12 with the drive mechanism 106. In other words, by changing the aperture diameter of the aperture stop 12, it is possible to control the σ value (coherence factor), which is the ratio of the numerical aperture NA of the illumination optical system 104 to the numerical aperture NA of the projection optical system 110.

The light beam that passes through the aperture of the field stop 13 passes through the imaging optical system 15 and illuminates the original 109 held by the original stage 101. A correction filter 14 is placed between the imaging optical system 15 and the original 109. This correction filter adjusts the optical characteristics of the light irradiating the original 109. The projection optical system 110 projects the pattern of the original 109 onto the substrate 115 held by the substrate stage 102 at a predetermined magnification (for example, 1/4x). This forms a pattern in the photosensitive agent on the substrate 115.

The exposure apparatus is configured to perform pattern exposure by blocking part of the light with a shield. The shield can be the blades of an aperture stop arranged inside the projection optical system 110. For example, an aperture stop (hereinafter referred to as an "NA stop") 111 with a substantially circular opening is arranged on or near the pupil plane of the projection optical system 110, and the size of this opening is controlled by a drive mechanism 112. The projection optical system 110 also has a drive mechanism 113 that changes the aberration of the projection optical system 110 by moving, rotating, and/or deforming at least one of the multiple lenses that make up the projection optical system 110. The drive mechanism 113 can include, for example, a mechanism that moves the lens in a direction along the optical axis (Z-axis) of the projection optical system 110 or two axes (X-axis and Y-axis) perpendicular to the optical axis, and a mechanism that rotates the lens around axes parallel to the two axes (X-axis and Y-axis) perpendicular to the optical axis.

The substrate stage 102 is movable in the X, Y, and Z directions. The substrate stage 102 is driven by a drive mechanism 116, which is controlled by a stage control unit 117. In the case of a scanning exposure apparatus, during exposure operations, the original stage 101 and substrate stage 102 are driven synchronously in the Y direction to perform scanning exposure.

The main control unit 103 comprehensively controls the illumination system control unit 108, projection system control unit 114, stage control unit 117, etc. The main control unit 103 includes memory for storing programs and data, and performs exposure operations by executing control programs stored in the memory. The main control unit 103 can be configured, for example, as a PLD (Programmable Logic Device) such as an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), a general-purpose computer with an embedded program, or a combination of all or part of these.

Next, the exposure method according to this embodiment will be described using the flowchart in Figure 2. Each of the following steps is executed by the main control unit 103.

Before starting an exposure job, in S1 the main control unit 103 measures the astigmatism of the projection optical system 110. An "exposure job" refers to, for example, a job related to a series of exposures in one lot (e.g., 25 substrates). The astigmatism is measured, for example, by the measurement system control unit 119 controlling the measurement sensor 118 arranged on the substrate stage 102.

In S2, the main control unit 103 determines whether the astigmatism obtained by measurement in S1 exceeds a threshold value. If the astigmatism does not exceed the threshold value, processing proceeds to exposure step S5, in which the substrate 115 is exposed via the projection optical system 110. If the astigmatism exceeds the threshold value, processing proceeds to S3. S3 is an adjustment step in which light irradiation (hereinafter referred to as "dummy exposure") is performed to irradiate the projection optical system 110 with light to reduce aberrations occurring in the projection optical system 110.

The dummy exposure performed in S3 will now be described. Light emitted from the light source 1 forms an effective light source distribution as shown in Figure 3(a) or 3(b) through the diffractive optical element 3 in the illumination optical system 104. The "effective light source distribution" refers to the light intensity distribution in the pupil plane of the illumination optical system 104 that illuminates the original 109. The dashed lines in Figures 3(a) and 3(b) represent σ = 1, with white areas having light intensity. The light of the generated effective light source distribution reaches the original stage 101 via the illumination optical system 104. At this time, the light emitted from the illumination optical system 104 enters the projection optical system 110 directly, without passing through the original 109 on the original stage 101. At this time, the original 109 may be removed from the original stage 101, or the original stage 101 carrying the original 109 may be driven to retract from the optical path.

Light entering the projection optical system 110 is irradiated onto the NA diaphragm 111, which is located on or near the pupil plane within the projection optical system 110. At this time, the size of the opening in the NA diaphragm 111 is controlled by the drive mechanism 112 to prevent light from reaching the substrate 115. When light entering the projection optical system 110 enters the lens group that makes up the projection optical system 110, the lenses are heated by absorption in the lens glass material and anti-reflection film, causing a change in the lens's refractive index and generating wavefront aberration. In addition, heat is accumulated in the blades of the NA diaphragm 111 that are hit by the light, warming nearby lenses, which can further increase the amount of wavefront aberration. For example, if an effective light source distribution such as that shown in Figure 3(a) is generated by the diffractive optical element 3 and light is incident on the projection optical system 110, the wavefront aberration of the projection optical system 110, which is generated by absorption in the lens glass material and anti-reflection film, becomes astigmatism as shown in Figure 4.

As described above, in the adjustment step S3, a dummy exposure is performed in which light is irradiated onto the optical elements included in the projection optical system 110 while at least a portion of the light beam is blocked by the blades of the NA diaphragm 111, which acts as a shield, in order to adjust the optical characteristics of the projection optical system 110. By performing such a dummy exposure, it is possible to reduce exposure astigmatism caused by the scanner's rectangular slit and non-rotationally symmetric exposure astigmatism that occurs when performing successive exposures using an original that contains many patterns in a specific direction.

After completing the adjustment step S3, in S4, the main control unit 103 performs a heat dissipation step to release heat accumulated in the blades of the NA diaphragm 111, which act as a shield. The operation of the NA diaphragm 111 during the adjustment and heat dissipation steps will be described with reference to Figure 7. In Figure 7, (a1) and (b1) are plan views of the NA diaphragm viewed from the -Z direction, and (a2) and (b2) are cross-sectional views along line A-A' in (a1) and (b1). During dummy exposure, the NA diaphragm 111 is closed, as shown in Figure 7(a1), to prevent light from reaching the substrate 115. In the heat dissipation step, the NA diaphragm 111 is controlled by the drive mechanism 112 to open the NA diaphragm 111 (fully open), as shown in Figure 7(b1). In the open state, the blades 121 of the NA diaphragm 111 are stored in the storage base 120 (storage unit). At this time, the heat that had accumulated in part of the blades 121 of the NA diaphragm 111 (the part indicated by the dashed line in Figure 7(a2)), which had become hot due to the irradiated light energy, is transferred to the storage base 120, thereby cooling the blades 121 of the NA diaphragm 111.

After the heat dissipation step S4 is completed, the exposure step S5 is carried out. In this exposure step, an exposure operation is performed to form a pattern in the photosensitive material on the substrate 115. At this time, the size of the opening in the NA diaphragm 111 is controlled by the drive mechanism 112 to create illumination conditions suitable for the pattern to be exposed. If this illumination condition is an especially small NA illumination condition, the blades of the NA diaphragm 111, which have retained heat, are largely exposed from the storage base 120 and heat up the nearby lenses, resulting in overcorrection of wavefront aberration.

The heat dissipation step S4, which prevents overcorrection of wavefront aberration, will be described with reference to the flowchart in Figure 5. The heat dissipation step S4 may include a determination step that determines the amount of heat dissipation from the blades 121 of the NA stop 111 based on the light irradiation conditions in the adjustment step S3 and the exposure conditions in the exposure step S5. In this embodiment, as shown in Figure 5, the determination step may include the following steps S41 to S43.

In S41, the main control unit 103 determines the temperature change of the blades 121 of the NA stop 111 in the adjustment step S3 based on the light irradiation conditions in the adjustment step S3 (first step). In this S41, for example, the main control unit 103 determines the energy (light energy) of the light irradiated in the adjustment step S3 (dummy exposure) based on the light irradiation conditions, that is, the irradiation time and illuminance. If the irradiation time of the light for the dummy exposure is t [s] and the illuminance is L [W/ ^m2 ], the light energy E [J/ ^m2 ] can be determined by the following formula:

E[J/m ² ]=t[s]×L[W/m ² ]
Next, the main control unit 103 calculates the temperature change of the NA stop 111 based on the calculated light energy. Specifically, it calculates the temperature change ΔT [°C] of the NA stop 111 when the calculated light energy is irradiated onto the NA stop 111 during dummy exposure. If the length of the blade 121 exposed into the optical path from the storage base 120 during dummy exposure is th_0 [m] and the thermal conductivity according to the material of the NA stop 111 is k [W/(m·K)], the temperature change ΔT [°C] of the NA stop 111 can be calculated by the following formula.

ΔT[℃]＝E[J/m ² ]／-k[W/(m・K)]×th_0[m]
In S42, the main control unit 103 calculates the aberration of the projection optical system 110 based on the temperature change calculated in S41 (second step). Here, the exposed length of the blades 121 of the NA stop 111 is set to th_1 [m] (0≦th_1<th_0). When the temperature change of the blades 121 of the NA stop 111 from T [°C] is ΔT [°C], the aberration ΔW [mλ] caused by the nearby lens is expressed by the following equation:

ΔW[mλ]=ΔT[℃]×α(th_1/th_0)
where α is a constant calculated as air thermal conductivity [W/(m·K)]/blade-lens distance [m]/lens thermal conductivity [W/(m·K)] × lens deformation sensitivity [nm/℃] × lens aberration sensitivity [mλ/nm].

In S43, the main control unit 103 determines the amount of heat dissipation so that the aberration calculated in S42 is smaller than the aberration tolerance determined depending on the exposure conditions in the exposure step S5 (third step). The amount of heat dissipation from the NA stop 111 is calculated based on the threshold value AS[mλ]. The threshold value AS[mλ] corresponds to the tolerance of astigmatism (aberration tolerance). In order to prevent overcorrection, it is sufficient that the aberration caused by this nearby lens is smaller than the threshold value AS[mλ] (aberration tolerance). That is,
ΔT[℃]×α＝ΔW[mλ]＜AS[mλ]
From this, the amount of heat dissipation, i.e., the required temperature change ΔT [°C] can be calculated.

The threshold value AS [mλ] is determined depending on the exposure conditions used in the exposure process S5. For example, if the numerical aperture (exposure NA) of the projection optical system, which is one of the exposure conditions, differs, the lens aberration sensitivity [mλ/nm] also changes, and therefore the generated aberration differs even for the same amount of surface deformation, and the required temperature change ΔT [°C] changes. Furthermore, if the exposure NA differs, the exposed length th_1 of the blades 121 of the NA stop 111, which remains heated, changes, and so the required temperature change ΔT [°C] also changes. Furthermore, when the exposure condition is the NA stop fully open (exposed length th_1 of the blades 121 = 0), ΔW [mλ] = 0, and there is no need to perform the heat dissipation process.

In S44, the main control unit 103 dissipates heat by fully opening the NA diaphragm 111 using the drive mechanism 112 for the time (heat dissipation time) required to achieve the required temperature change (ΔT [°C]) determined in S43. For example, the amount of change in temperature of the blades 121 of the NA diaphragm 111 over time (heat dissipation time) when the NA diaphragm 111 is fully opened after a dummy exposure can be determined by simulation. Figure 6 is a graph showing an example of the characteristics of the change in temperature of the NA diaphragm 111 (at the blade tips) over time determined by simulation. In this case, the main control unit 103 can determine the heat dissipation time based on the characteristics of the change in temperature of the blades 121 of the NA diaphragm 111 over time determined by simulation. Therefore, in this case, the main control unit 103 determines the time required to achieve the required temperature change (ΔT [°C]) determined in S43 based on the characteristics shown in Figure 6. Note that the relationship shown in Figure 6 may be determined not by simulation, but by heating the NA diaphragm alone before assembling the device, and then measuring the amount of change in temperature of the NA diaphragm 111 over time when the NA diaphragm 111 is fully open. In this case, the main control unit 103 determines the heat dissipation time based on the results of actually measuring the amount of change in temperature of the blades 121 of the NA diaphragm 111 over time.

In the heat dissipation step S4 according to the flowchart of Figure 5 above, the amount of heat dissipation from the blades 121 of the NA stop 111 was determined based on both the light irradiation conditions in the adjustment step S3 and the exposure conditions in the exposure step S5. However, in the heat dissipation step S4, the amount of heat dissipation from the blades 121 of the NA stop 111 may also be determined based on either the light irradiation conditions in the adjustment step S3 or the exposure conditions in the exposure step S5. In other words, in the heat dissipation step S4, the amount of heat dissipation from the blades 121 of the NA stop 111 may be determined based on at least one of the light irradiation conditions in the adjustment step S3 and the exposure conditions in the exposure step S5.

As explained above, by controlling the heat dissipation time of the NA aperture 1110, it is possible to prevent overcorrection of wavefront aberration (astigmatism).

Figure 8 is a cross-sectional view of a main portion of the NA diaphragm 111 according to a modified example. In this modified example, a gap 122 is provided within the storage base 120 of the NA diaphragm 111. By circulating air or liquid through this gap 122, the storage base 120 and the blades 121 arranged thereon are air- or liquid-cooled. This improves the cooling efficiency of the blades 121 and shortens the heat dissipation time.

<Embodiment of an article manufacturing method>
The article manufacturing method according to an embodiment of the present invention is suitable for manufacturing articles such as microdevices, such as semiconductor devices, and elements having microstructures. The article manufacturing method according to this embodiment includes a step of forming a latent image pattern on a photosensitive agent applied to a substrate using the exposure apparatus described above in accordance with the exposure method described above (an exposure step of exposing the substrate), and a development step of developing the substrate on which the latent image pattern has been formed. Furthermore, this manufacturing method includes other well-known steps (oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.). The article manufacturing method according to this embodiment is advantageous over conventional methods in at least one of article performance, quality, productivity, and production cost.

The disclosure of the present specification includes at least the following techniques.
(Item 1)
An exposure method for exposing a substrate, comprising:
an adjusting step of irradiating light onto an optical element included in the projection optical system in a state where at least a part of the light beam is blocked by a shielding member in order to adjust the optical characteristics of the projection optical system;
a heat dissipation step of dissipating heat accumulated in the shield by the adjustment step;
an exposure step of exposing the substrate via the projection optical system after the heat dissipation step,
an exposure method, wherein in the heat dissipation step, heat is dissipated from the shield at an amount based on at least one of the light irradiation conditions in the adjustment step and the exposure conditions in the exposure step.
(Item 2)
2. The exposure method according to item 1, wherein in the heat dissipation step, heat is dissipated from the shield at an amount based on the light irradiation conditions in the adjustment step and the exposure conditions in the exposure step.
(Item 3)
The heat dissipation step includes:
a first step of determining a temperature change of the shield in the adjusting step based on the light irradiation conditions;
a second step of determining the aberration of the projection optical system based on the temperature change;
a third step of determining the amount of heat dissipation so that the aberration is smaller than an aberration tolerance determined depending on the exposure conditions;
3. The exposure method according to item 2, comprising:
(Item 4)
the light irradiation conditions include light irradiation time and illuminance,
In the first step, energy of the light irradiated in the adjusting step is calculated based on the irradiation time and the illuminance, and the temperature change is calculated based on the energy.
4. The exposure method according to item 3.
(Item 5)
5. The exposure method according to item 3 or 4, wherein the exposure conditions include a numerical aperture of the projection optical system.
(Item 6)
6. The exposure method according to any one of items 1 to 5, wherein the shielding object is a blade of an aperture stop arranged inside the projection optical system.
(Item 7)
7. The exposure method according to item 6, wherein the aperture stop is an NA stop arranged on or near the pupil plane of the projection optical system.
(Item 8)
the aperture stop includes a storage portion that stores the blades in an open state,
In the heat dissipation step, the aperture stop is opened to transfer heat from the blades to the housing, thereby dissipating heat from the shield.
8. The exposure method according to item 6 or 7.
(Item 9)
9. The exposure method according to any one of items 1 to 8, wherein the amount of heat dissipation in the heat dissipation step is controlled by the heat dissipation time of the shield.
(Item 10)
10. The exposure method according to item 9, wherein the heat radiation time is determined based on a characteristic of the change in temperature of the shield with respect to the elapsed time, the characteristic being obtained by simulation.
(Item 11)
10. The exposure method according to item 9, wherein the heat radiation time is determined based on a result obtained by actually measuring the amount of change in the temperature of the shield with respect to the elapsed time.
(Item 12)
12. The exposure method according to any one of items 1 to 11, wherein the adjusting step is performed in a state where light is prevented from reaching the substrate by the shielding member.
(Item 13)
An exposure apparatus for exposing a substrate, comprising:
a projection optical system;
a shield disposed inside the projection optical system;
a control unit,
The control unit
an adjusting step of irradiating light onto an optical element included in the projection optical system while blocking at least a part of the light beam with the blocking member in order to adjust the optical characteristics of the projection optical system;
a heat dissipation step of dissipating heat accumulated in the shield by the adjustment step;
an exposure step of exposing the substrate via the projection optical system after the heat dissipation step;
configured to:
the control unit is further configured to determine the amount of heat dissipation from the shield in the heat dissipation step based on at least one of light irradiation conditions in the adjustment step and exposure conditions in the exposure step.
(Item 14)
an exposure step of exposing a substrate according to the exposure method according to any one of items 1 to 12;
a developing step of developing the exposed substrate;
and manufacturing an article from the developed substrate.

The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Therefore, the following claims are appended to clarify the scope of the invention.

101: master stage, 102: substrate stage, 103: main control unit, 104: illumination optical system, 109: master, 110: projection optical system, 111: NA aperture, 115: substrate

Claims (14)

An exposure method for exposing a substrate, comprising:
an adjusting step of irradiating light onto an optical element included in the projection optical system in a state where at least a part of the light beam is blocked by a shielding member in order to adjust the optical characteristics of the projection optical system;
a heat dissipation step of dissipating heat accumulated in the shield by the adjustment step;
an exposure step of exposing the substrate via the projection optical system after the heat dissipation step,
an exposure method, wherein in the heat dissipation step, heat is dissipated from the shield at an amount based on at least one of the light irradiation conditions in the adjustment step and the exposure conditions in the exposure step. The exposure method described in claim 1, wherein in the heat dissipation process, heat is dissipated from the shield at an amount based on the light irradiation conditions in the adjustment process and the exposure conditions in the exposure process. The heat dissipation step includes:
a first step of determining a temperature change of the shield in the adjusting step based on the light irradiation conditions;
a second step of determining the aberration of the projection optical system based on the temperature change;
a third step of determining the amount of heat dissipation so that the aberration is smaller than an aberration tolerance determined depending on the exposure conditions;
3. The exposure method according to claim 2, further comprising: the light irradiation conditions include light irradiation time and illuminance,
In the first step, energy of the light irradiated in the adjusting step is calculated based on the irradiation time and the illuminance, and the temperature change is calculated based on the energy.
4. The exposure method according to claim 3. The exposure method according to claim 3, wherein the exposure conditions include the numerical aperture of the projection optical system. The exposure method described in claim 1, wherein the shielding object is a blade of an aperture stop arranged inside the projection optical system. The exposure method described in claim 6, wherein the aperture stop is an NA stop arranged on or near the pupil plane of the projection optical system. the aperture stop includes a storage portion that stores the blades in an open state,
In the heat dissipation step, the aperture stop is opened to transfer heat from the blades to the housing, thereby dissipating heat from the shield.
7. The exposure method according to claim 6. The exposure method described in claim 1, characterized in that the amount of heat dissipation in the heat dissipation process is controlled by the heat dissipation time of the shield. The exposure method of claim 9, wherein the heat dissipation time is determined based on the characteristics of the temperature change of the shield over time, determined by simulation. The exposure method described in claim 9, wherein the heat dissipation time is determined based on the results of measuring the amount of change in the temperature of the shield over time. The exposure method described in claim 1, wherein the adjustment process is performed in a state where light is prevented from reaching the substrate by the shield. An exposure apparatus for exposing a substrate,
a projection optical system;
a shield disposed inside the projection optical system;
a control unit,
The control unit
an adjusting step of irradiating light onto an optical element included in the projection optical system while blocking at least a part of the light beam with the blocking member in order to adjust the optical characteristics of the projection optical system;
a heat dissipation step of dissipating heat accumulated in the shield by the adjustment step;
an exposure step of exposing the substrate via the projection optical system after the heat dissipation step;
configured to:
the control unit is further configured to determine the amount of heat dissipation from the shield in the heat dissipation step based on at least one of light irradiation conditions in the adjustment step and exposure conditions in the exposure step. an exposure step of exposing a substrate according to the exposure method of any one of claims 1 to 12;
a developing step of developing the exposed substrate;
and manufacturing an article from the developed substrate.