Illumination optical system, exposure apparatus, method for manufacturing article, and illumination method

Abstract

To provide an illumination optical system capable of reducing nonuniformity of at least one of spectral illuminance distribution by first light from a first light source on a surface to be illuminated and spectral illuminance distribution by second light from a second light source on the surface.SOLUTION: An illumination optical system comprises: a first light source which emits first light having a first wavelength; a second light source which emits second light having a second wavelength different from the first wavelength; and a control unit which performs at least one of a first control step of controlling the first light source such that first illuminance distribution by the first light on a surface to be illuminated becomes first target illuminance distribution, and a second control step of controlling the second light source such that second illuminance distribution by the second light on a surface to be illuminated becomes second target illuminance distribution.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to an illumination optical system, an exposure apparatus, an article manufacturing method, and an illumination method. [Background technology]

[0002] 2. Description of the Related Art Conventionally, in exposure apparatuses, there has been a demand for improvement in the uniformity of the line width of a pattern formed in a resist on the surface of a substrate, that is, the critical dimension (hereinafter referred to as resist CD) of the resist. In this exposure apparatus, it is known that the uniformity of the resist CD decreases depending on the non-uniformity of the illuminance distribution of the exposure light guided onto the substrate surface, that is, the illuminance unevenness.

[0003] Patent document 1 discloses an exposure apparatus that reduces uneven illuminance of exposure light guided onto the substrate surface of a substrate by adjusting the light output of at least one of multiple unit areas included in a light source unit provided in an illumination optical system. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-228794 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, an exposure apparatus may use an illumination optical system having a first light source that emits first light having a first wavelength and a second light source that emits second light having a second wavelength different from the first wavelength. In this case, in order to suppress a decrease in the uniformity of the resist CD, it is necessary to take into consideration the non-uniformity of the spectral irradiance distribution of the first light and the spectral irradiance distribution of the second light on the substrate surface.

[0006] Therefore, an object of the present invention is to provide an illumination optical system that can reduce the nonuniformity of at least one of the spectral illuminance distribution of a first light from a first light source and the spectral illuminance distribution of a second light from a second light source on an illuminated surface. [Means for solving the problem]

[0007] The illumination optical system according to the present invention is characterized by comprising: a first light source that emits first light having a first wavelength; a second light source that emits second light having a second wavelength different from the first wavelength; and a control unit that performs at least one of a first control step of controlling the first light source so that a first illuminance distribution due to the first light on an irradiated surface becomes a first target illuminance distribution; and a second control step of controlling the second light source so that a second illuminance distribution due to the second light on the irradiated surface becomes a second target illuminance distribution. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an illumination optical system that can reduce the nonuniformity of at least one of the spectral illuminance distribution of the first light from the first light source and the spectral illuminance distribution of the second light from the second light source on the illuminated surface. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of an exposure apparatus equipped with an illumination optical system according to a first embodiment. [Figure 2] FIG. 1 is a cross-sectional view of an illumination optical system according to a first embodiment. [Figure 3] 3A and 3B are a partially enlarged cross-sectional view and a partially enlarged front view of a light source included in the illumination optical system according to the first embodiment. [Figure 4] 2A and 2B are a front view and a partially enlarged perspective view of a light source included in the illumination optical system according to the first embodiment. [Figure 5] 10A and 10B are diagrams showing the composite illuminance, spectral illuminance, spectral illuminance ratio, and resist CD at each position on the illuminated surface by the illumination optical system of the comparative example, as well as the relationship between the spectral illuminance ratio and resist CD. [Figure 6]FIG. 3 is a block diagram of a plurality of control units included in a light source provided in the illumination optical system according to the first embodiment. [Figure 7] 3A and 3B are diagrams showing spectral illuminance at each position on a surface to be illuminated by the illumination optical system according to the first embodiment. [Figure 8] 5 is a flowchart showing a process for forming a predetermined distribution of spectral illuminance on an illuminated surface by an illumination optical system according to the first embodiment. [Figure 9] 3A and 3B are diagrams showing spectral illuminance at each position on a surface to be illuminated by the illumination optical system according to the first embodiment. [Figure 10] 3A and 3B are diagrams showing spectral illuminance at each position on a surface to be illuminated by the illumination optical system according to the first embodiment. [Figure 11] FIG. 10 is a partially enlarged front view of a light source included in an illumination optical system according to a modified example of the first embodiment. [Figure 12] FIG. 10 is a cross-sectional view of an illumination optical system according to a second embodiment. [Figure 13] FIG. 10 is a front view of a variable field diaphragm included in an illumination optical system according to a second embodiment. [Figure 14] 10 is a flowchart showing a process for forming a predetermined distribution of spectral illuminance on an illuminated surface by an illumination optical system according to a second embodiment. [Figure 15] 10A and 10B are diagrams showing spectral illuminance at each position on a surface to be illuminated by an illumination optical system according to a second embodiment. [Figure 16] 10 is a diagram showing the relationship between the combined illuminance and the resist CD in the illumination optical system according to the third embodiment. [Figure 17] 10 is a flowchart showing a process for forming predetermined distributions of spectral illuminance and composite illuminance on an illuminated surface by an exposure apparatus equipped with an illumination optical system according to a third embodiment. [Figure 18] 10A and 10B are diagrams showing spectral illuminance, composite illuminance, and spectral characteristics at various positions on an illuminated surface by an illumination optical system according to a third embodiment. [Figure 19] 10 is a flowchart showing a process for forming predetermined distributions of spectral illuminance and composite illuminance on an illuminated surface by an exposure apparatus equipped with an illumination optical system according to a fourth embodiment. [Figure 20]10A and 10B are diagrams showing spectral illuminance, composite illuminance, and spectral characteristics at various positions on an illuminated surface by an illumination optical system according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] The illumination optical system according to this embodiment will be described in detail below with reference to the accompanying drawings. Note that the drawings may be drawn at a scale different from the actual scale in order to facilitate understanding of this embodiment. In the following, the direction parallel to the optical axis of the projection optical system 101 is defined as the Z direction, the direction in which the substrate 5 is scanned in a plane perpendicular to the optical axis of the projection optical system 101 is defined as the Y direction, and the non-scanning direction perpendicular to the Y direction is defined as the X direction.

[0011] [First embodiment] Conventionally, an exposure apparatus is used to transfer a pattern formed on a mask onto a substrate.

[0012] In particular, in a projection exposure apparatus, an illumination optical system guides exposure light onto a mask surface of a mask (original), which is an irradiated surface, thereby illuminating the mask surface. The exposure light that has passed through the mask surface is then guided onto the substrate surface of a substrate (plate) by a projection optical system, whereby an image of the pattern formed on the original is projected onto the substrate surface.

[0013] In an exposure apparatus, the uniformity of the critical dimension (hereinafter referred to as resist CD) of the resist on the surface of the substrate is used as an index representing important performance. Here, the resist CD means the line width of a pattern formed in the resist on the surface of the substrate in an exposure apparatus.

[0014] A decrease in the uniformity of resist CD in an exposure tool leads to variations and defects in the performance of products manufactured from the corresponding pattern formed on the substrate surface. Factors that can cause a decrease in resist CD uniformity in an exposure tool include aberrations in the illumination optical system and projection optical system, and focus deviations at various positions on the substrate surface. In particular, non-uniformity of the illuminance distribution (illuminance unevenness) on the illuminated surface due to the illumination optical system is a typical factor, and it is therefore preferable to reduce this.

[0015] Conventionally, mercury lamps have been used as light sources provided in illumination optical systems mounted on exposure apparatuses, but in recent years, the use of light emitting diode (LED) elements as solid-state light source elements has been considered. LED elements have advantages in terms of lifespan and energy consumption, since they require a short time for their light output to stabilize and do not need to be constantly emitting light like mercury lamps.

[0016] Conventionally, an illumination optical system has been proposed that uses a plurality of LED elements to illuminate a target surface with high illuminance. Specifically, in this illumination optical system, a plurality of lights having different wavelengths emitted from a plurality of LED elements are combined on the optical path.

[0017] In the illumination optical system, the balance between the light amounts of the plurality of light beams having different wavelengths emitted from the plurality of LED elements is adjusted according to the illuminance characteristics and spectral characteristics of the resist. However, this illumination optical system does not take into consideration individual differences between a plurality of LED elements, differences in characteristics regarding light emission wavelengths, and the like.

[0018] That is, if there are individual differences or differences in characteristics of light emission wavelengths among the plurality of LED elements in the illumination optical system, different illuminance distributions will be formed on the illuminated surface for the plurality of wavelengths. Such different illuminance distributions for a plurality of wavelengths on the irradiated surface result in differences in spectral characteristics at each position on the irradiated surface, which leads to a decrease in the uniformity of the resist CD. That is, in this illumination optical system, no consideration is given to the different illuminance distributions for a plurality of wavelengths that result in such differences in spectral characteristics.

[0019] In addition, an illumination optical system has also been proposed that reduces uneven illuminance on an illuminated surface by adjusting the light output of some of the LED elements when illuminating the illuminated surface using multiple LED elements. Specifically, in this illumination optical system, a light source consisting of multiple LED elements is divided into multiple unit areas, and the illuminance distribution on the illuminated surface is adjusted by adjusting the light output of each of the multiple divided unit areas.

[0020] However, in this illumination optical system, no consideration is given to the illuminance distribution for each of the multiple wavelengths formed on the illuminated surface by the multiple lights having different wavelengths emitted from the multiple LED elements. In the illumination optical system, each unit area is not formed so as to adjust the illuminance distribution for each of the plurality of wavelengths.

[0021] Therefore, this illumination optical system does not take into account the different illuminance distributions for multiple wavelengths that result in differences in spectral characteristics, and when multiple LED elements that emit multiple light beams with different wavelengths are used, this causes a decrease in the uniformity of the resist CD. Therefore, the purpose of this embodiment is to provide an illumination optical system that can suppress the deterioration of the uniformity of the resist CD by appropriately correcting the illuminance distribution for each of the multiple wavelengths formed on the irradiated surface by multiple lights of different wavelengths emitted from multiple LED elements.

[0022] FIG. 1 shows a schematic cross-sectional view of an exposure apparatus 100 equipped with an illumination optical system 10 according to the first embodiment. The exposure apparatus 100 is equipped with an illumination optical system 10, a projection optical system 101, and a substrate stage 6 according to this embodiment, and is configured to project an image of a pattern formed on the mask surface of a mask 19 onto a substrate 5, thereby exposing the substrate 5. The illumination optical system 10 according to this embodiment is configured to illuminate the mask surface (original surface) of a mask 19 (original) placed at the position of the surface to be illuminated with exposure light.

[0023] The projection optical system 101 is configured to project an image of a pattern formed on the mask surface onto the substrate surface of the substrate 5, which is arranged so that the substrate surface is positioned at a position optically conjugate with the mask surface of the mask 19. Specifically, the projection optical system 101 has mirrors 1, 2, and 3, and is formed by a reflective optical system that reflects incident exposure light from mirror 1, mirror 2, mirror 3, mirror 2, and mirror 1 in this order.

[0024] As described above, the projection optical system 101 is formed by a catoptric system that can reduce chromatic aberration compared to a dioptric system, and is therefore suitable for broadband illumination. In other words, the projection optical system 101 is not limited to a reflective optical system, and may be formed by a catadioptric or dioptric system, but in that case, it becomes necessary to consider the correction of chromatic aberration according to the wavelength used.

[0025] The substrate stage 6 is configured to be movable while holding the substrate 5 . In addition, the substrate stage 6 is provided with a sensor 7 for measuring the illuminance on the surface of the substrate 5. Then, by moving the substrate stage 6 in the XY plane and displacing the sensor 7 relative to the projection optical system 101, the illuminance at each position on the substrate surface of the substrate 5, i.e., the illuminance distribution, can be measured.

[0026] FIG. 2 shows a schematic cross-sectional view of the illumination optical system 10 according to this embodiment. The illumination optical system 10 according to this embodiment includes a first light source 11a, a second light source 11b, a condenser lens 12, an optical integrator 13, an aperture stop 14, and a second condenser lens 15 (optical elements). The illumination optical system 10 according to this embodiment also includes a wavelength combining unit 16, a control unit 27, and a calculation unit 29 (control unit).

[0027] The first light source 11a is an LED array light source formed of a plurality of LED (Light Emitting Diode) elements each having a wavelength characteristic λ1 (first wavelength) with a peak wavelength of, for example, 405 nm. The second light source 11b is an LED array light source formed of a plurality of LED elements each having a wavelength characteristic λ2 (second wavelength) with a peak wavelength of, for example, 365 nm.

[0028] The wavelength combining unit 16 is configured to combine multiple light beams (first light beams) emitted from the LED elements of the first light source 11a and multiple light beams (second light beams) emitted from the LED elements of the second light source 11b, and then guide the combined light beams to the condenser lens 12. Specifically, the wavelength combining unit 16 is, for example, a dichroic mirror, which is a glass substrate on which an optical thin film is formed that reflects light having a wavelength of 365 nm while transmitting light having a wavelength of 405 nm.

[0029] That is, the first light source 11a may be configured to emit light having a peak wavelength other than 405 nm, as long as the light passes through the dichroic mirror that forms the wavelength combining unit 16. The first light source 11a may be formed by a plurality of LED elements that emit a plurality of light beams having different wavelengths, each of which passes through a dichroic mirror that forms the wavelength combining unit 16.

[0030] Furthermore, the second light source 11b may be configured to emit light having a peak wavelength other than 365 nm, as long as the light is reflected by the dichroic mirror that forms the wavelength combining unit 16. The second light source 11b may be formed by a plurality of LED elements that emit a plurality of light beams having different wavelengths, each of which is reflected by a dichroic mirror that forms the wavelength combining unit 16.

[0031] The condenser lens 12 is configured to condense the plurality of light beams guided by the wavelength combining unit 16 onto the incident surface of the optical integrator 13 . The optical integrator 13 is formed from a large number of microlenses having the same shape, for example, a fly's eye lens.

[0032] The optical integrator 13 then splits the wavefronts of the multiple light beams guided onto the entrance surface by the condenser lens 12, thereby forming multiple light source images of the first light source 11a and the second light source 11b on the exit surface. In other words, optical images of the first light source 11a and the second light source 11b are formed on the exit surface of each of the many microlenses that form the optical integrator 13, thereby forming secondary light sources.

[0033] In the illumination optical system 10 according to this embodiment, it is preferable that the light emitting surfaces of the first light source 11a and the second light source 11b are disposed near the front focal position of the condenser lens 12. It is also preferable that the entrance surface of the optical integrator 13 is located near the rear focal position of the condenser lens 12 .

[0034] However, the light emitting surfaces of the first light source 11 a and the second light source 11 b and the incident surface of the optical integrator 13 do not need to be perfectly aligned with the focal position of the condenser lens 12 . That is, even if they are slightly deviated from the focal position of the condenser lens 12, the effects of the illumination optical system 10 according to this embodiment can be achieved.

[0035] The aperture stop 14 is configured to form an angular distribution of the illumination light that illuminates the mask surface of the mask 19 . Specifically, by providing an annular or quadrupole-shaped transmission region in the aperture stop 14, it is possible to form modified illumination such as annular or quadrupole. It is preferable that the aperture stop 14 be disposed near the exit surface of the optical integrator 13 .

[0036] The second condenser lens 15 is configured to condense the light that has passed through the aperture stop 14 onto the mask surface of the mask 19 . The illumination optical system 10 according to this embodiment, with the above-described configuration, can illuminate the mask surface of the mask 19 with illumination light formed from a plurality of light beams emitted from the first light source 11a and the second light source 11b.

[0037] As described above, in the exposure apparatus 100, the mask surface of the mask 19 and the substrate surface of the substrate 5 are optically conjugate with each other, so the sensor 7 may be positioned to measure the illuminance on the mask surface of the mask 19, as shown in FIG. 2. The output from the sensor 7 arranged to measure the illuminance on the mask surface of the mask 19 is input to the calculation unit 29.

[0038] The calculation unit 29 calculates appropriate adjustment amounts based on the difference from the target values ​​for each of the composite illuminance distribution and the spectral characteristic distribution obtained from the illuminance measured at each position on the mask surface of the mask 19, and outputs the adjustment amounts to the control unit 27. The control unit 27 adjusts the light output of each of the first light source 11a and the second light source 11b in accordance with the output from the calculation unit 29 so as to reduce the difference between the combined illuminance distribution and the spectral characteristic distribution.

[0039] Specifically, the control unit 27 is formed from a plurality of control units 27a, 27b, 27c, etc. (partial control units), and adjusts the light output of each light source unit of the first light source 11a and the second light source 11b connected to each control unit. The detailed operations of the control unit 27 and the calculation unit 29 in the illumination optical system 10 according to this embodiment will be described later.

[0040] In the illumination optical system 10 according to this embodiment, a wavelength combining section 16 formed by a dichroic mirror is provided, but the illumination optical system 10 according to this embodiment is not limited to this and may be formed with a simple configuration that does not include the wavelength combining section 16 and the second light source 11b. That is, in this case, it is sufficient to provide the first light source 11a with both a plurality of LED elements each having the wavelength characteristic λ1 and a plurality of LED elements each having the wavelength characteristic λ2. The plurality of light beams emitted from the first light source 11 a are then directly condensed by the condenser lens 12 , and the condensed plurality of light beams are then guided to the optical integrator 13 .

[0041] 3(a) and 3(b) respectively show a partially enlarged schematic cross-sectional view and a partially enlarged schematic front view of a first light source 11a provided in the illumination optical system 10 according to this embodiment. The second light source 11b has the same configuration as the first light source 11a except for the coordinate system and wavelength characteristics, and therefore a description thereof will be omitted.

[0042] In the first light source 11a, since a single LED element has smaller radiation energy than a high-pressure mercury lamp, when the illumination optical system 10 according to this embodiment is used in the exposure apparatus 100, it is essentially necessary to provide multiple LED elements. Specifically, the first light source 11a has a substrate 21, a plurality of LED elements 22, and a plurality of light collecting portions .

[0043] The LED elements 22 are arranged in a square lattice pattern on the substrate 21 as shown in FIG. 3(b). However, the LED elements 22 may be arranged in a different manner, such as a staggered arrangement.

[0044] The radiation angle of light from the LED elements 22 is 60 to 70 degrees. Therefore, in the first light source 11a, in order to capture the radiated light flux from each of the plurality of LED elements 22 by an optical system provided downstream, a light collecting unit 23 for collimating the radiated light flux is provided directly above each of the plurality of LED elements 22. That is, each of the plurality of light collecting sections 23 has a collimator lens provided so as to correspond one-to-one to each of the plurality of LED elements 22.

[0045] In FIG. 3(b), the optical axis of the corresponding collimator lens extends in the Z direction so as to pass through the intersection of each dashed dotted line parallel to the Y direction and each dashed dotted line parallel to the X direction. However, the optical axis of each collimator lens and the center of the light-emitting surface 20 of the corresponding LED element 22 do not need to coincide with each other within the XY plane.

[0046] In addition, by arranging the light-emitting surface 20 of the corresponding LED element 22 near the front focal position of a predetermined light-collecting section 23, a distribution of Fourier-transformed light information on the light-emitting surface 20 of the corresponding LED element 22 is formed near the rear focal position of the predetermined light-collecting section 23. By positioning the rear focal position of each of the multiple light-collecting sections 23 near the front focal position of the condenser lens 12, the light-emitting surface 20 of each of the multiple LED elements 22 and the incident surface of the optical integrator 13 become optically conjugate with each other.

[0047] In other words, the optical images of the light emitting surfaces 20 of the plurality of LED elements 22 are projected onto the incident surface of the optical integrator 13 in a superimposed manner, thereby forming a pupil intensity distribution. It is not necessary that all of the LED elements 22 have the above configuration, but it is sufficient that almost all, for example 90% or more of the LED elements 22 have the above configuration.

[0048] FIG. 4(a) shows a schematic front view of a first light source 11a provided in the illumination optical system 10 according to this embodiment. As shown in FIG. 4(a), the first light source 11a has an array of ten light source units 111a, 111b, 111c, 111d, 111e, 111f, 111g, 111h, 111i, and 111j, each having a plurality of LED elements 22.

[0049] In other words, the first light source 11a is formed from a light source unit group (first light source unit group) including the light source units 111a to 111j. Generally, the size of the focusing section 23 is limited due to manufacturing reasons, so by dividing the first light source 11a into multiple light source units as in the illumination optical system 10 of this embodiment, it is possible to form a sufficiently large first light source 11a using multiple LED elements 22. Similarly, the second light source 11b is also formed from a light source unit group (second light source unit group) including ten light source units.

[0050] FIG. 4(b) is a schematic perspective view of a light source unit 111a included in a first light source 11a provided in the illumination optical system 10 according to this embodiment. The light source units 111b to 111j have the same configuration as the light source unit 111a, and therefore the description thereof will be omitted.

[0051] In the light source unit 111a, as shown in FIG. 4(b), a plurality of LED elements 22 are connected in series via wiring 24, and power is supplied through the wiring 24. However, the present invention is not limited to this, and the wiring 24 corresponding to each of the plurality of LED elements 22 may be connected one-to-one to supply power via the corresponding wiring 24 .

[0052] In order to improve productivity in exposure apparatus 100, it is necessary to illuminate mask 19 with high illuminance. In this case, it is required that the first light source 11a provided in the illumination optical system 10 according to this embodiment, which is mounted on the exposure apparatus 100, has multiple LED elements 22 arranged at high density and is driven with high power.

[0053] However, when each of the LED elements 22 is driven with high power, a large amount of heat is generated. The luminous efficiency of the LED elements 22 changes depending on the temperature, so in order to stabilize the illuminance on the mask 19, it is necessary to control the temperature of each of the plurality of LED elements 22.

[0054] Therefore, in the light source unit 111a, each of the plurality of LED elements 22 is in contact with a heat sink (heat dissipation member) 25. A cooling medium controlled to a predetermined temperature by a refrigerator (not shown) is caused to flow through a cooling flow path 26 provided in the heat sink 25, thereby cooling the LED elements 22.

[0055] Next, a characteristic configuration of the illumination optical system 10 according to this embodiment will be described. First, in a conventional illumination optical system, consideration is generally given to the combined illuminance distribution of a plurality of lights having mutually different wavelengths contained in the illumination light that illuminates the illuminated surface.

[0056] On the other hand, in an illumination optical system that employs a method of combining multiple lights each having a different wavelength, there is a risk of variations in the spectral characteristics of the illumination light that illuminates the illuminated surface due to differences in the individual light sources and differences in the changes in the characteristics of each light source over time. Furthermore, the spectral characteristics of the illumination light may become non-uniform depending on the position on the illuminated surface, and this non-uniformity becomes particularly noticeable when the illuminated surface is large, such as the mask surface of mask 19 in exposure apparatus 100.

[0057] 5(a) to 5(e) show the problems with such conventional illumination optical systems. Specifically, FIG. 5(a) shows the composite illuminance distribution on the illuminated surface by an illumination optical system of a comparative example corresponding to a conventional illumination optical system, i.e., the composite illuminance unevenness ΔI(X) at each position in the X direction on the illuminated surface.

[0058] The illumination optical system of the comparative example shown here has the same optical configuration as the illumination optical system 10 according to this embodiment. The term "unevenness in composite illuminance" used here refers to unevenness in illuminance on the illuminated surface due to all light contained in the illumination light emitted from the illumination optical system.

[0059] FIG. 5(b) shows the spectral illuminance distribution on the irradiated surface by the illumination optical system of the comparative example, i.e., the spectral illuminance unevenness ΔI1(X) and ΔI2(X) of the wavelength characteristics λ1 and λ2 at each position in the X direction on the irradiated surface. Note that the spectral illuminance unevenness of wavelength characteristics λ1 and wavelength characteristics λ2 referred to here means the unevenness of illuminance on the illuminated surface due to multiple lights having wavelength characteristics λ1 and multiple lights having wavelength characteristics λ2, which are contained in the illumination light emitted from the illumination optical system. That is, the composite illuminance unevenness ΔI(X) and the spectral illuminance unevenness ΔI1(X) and ΔI2(X) are indices that represent the uniformity of the corresponding illuminance distributions, and can be specifically expressed as in the following equations (1), (2), and (3).

number

number

number

[0060] In equations (1) and (2), I1(X) represents the Y-direction integrated illuminance obtained by integrating the illuminance of multiple lights having wavelength characteristics λ1 at each position in the Y direction where the X-direction position on the irradiated surface is X. The denominator on the right side of equation (2) represents the average value of I1(X), that is, the average value of the Y-direction integrated illuminance of a plurality of lights having wavelength characteristics λ1 at each position in the X direction on the irradiated surface.

[0061] In addition, in equations (1) and (3), I2(X) is the Y-direction integrated illuminance obtained by integrating the illuminance of multiple lights having wavelength characteristics λ2 at each position in the Y direction where the X-direction position on the irradiated surface is X. The denominator on the right side of equation (3) represents the average value of I2(X), that is, the average value of the integrated illuminance in the Y direction by a plurality of lights having wavelength characteristics λ2 at each position in the X direction on the irradiated surface. The denominator on the right side of equation (1) represents the average value of I1(X) + I2(X), i.e., the average value of the sum of the integrated illuminance in the Y direction due to the multiple light beams having wavelength characteristics λ1 and the multiple light beams having wavelength characteristics λ2 at each position in the X direction on the irradiated surface.

[0062] As shown in FIG. 5(a), the combined illuminance distribution on the illuminated surface by the illumination optical system of the comparative example is formed to be approximately uniform. On the other hand, the spectral illuminance distributions of the wavelength characteristics λ1 and λ2 on the illuminated surface by the illumination optical system of the comparative example have mutually different shapes, as shown in FIG. 5(b).

[0063] In other words, this indicates that even if the composite illuminance I(X) on the irradiated surface does not have position dependence in the X direction, the position dependences of the spectral illuminance unevenness ΔI1(X) and ΔI2(X) of the wavelength characteristics λ1 and λ2 on the irradiated surface are different from each other. Furthermore, if the spectral illuminance unevenness ΔI1(X) and ΔI2(X) of the wavelength characteristics λ1 and λ2 on the irradiated surface have different position dependencies, the spectral characteristics of the exposure light guided to each position on the irradiated surface will be different from each other.

[0064] FIG. 5(c) shows the spectral illuminance ratio I1(X) / I2(X) at each position in the X direction on the illuminated surface by the illumination optical system of the comparative example. FIG. 5(d) shows the ratio CD / CD of the resist line width (critical dimension: CD) to the reference resist line width (target CD) in response to changes in the spectral illuminance ratio I1(X) / I2(X) using the illumination optical system of the comparative example. tThis shows the change in

[0065] In FIG. 5(d), the composite illuminance I(X) is the same at each position in the X direction on the irradiated surface, and the CD / CD when the spectral illuminance ratio I1(X) / I2(X) is 100%. t is set at 100%. As shown in FIG. 5(d), in the illumination optical system of the comparative example, the resist CD changes linearly in response to changes in the spectral illuminance ratio I1(X) / I2(X).

[0066] FIG. 5(e) shows the ratio CD / CD at each position in the X direction on the illuminated surface by the illumination optical system of the comparative example, obtained from FIGS. 5(c) and 5(d). t This shows: As shown in FIG. 5(e), in the illumination optical system of the comparative example, the resist CD is not the same at each position in the X direction on the illuminated surface.

[0067] Here, position L at X=-350 and position R at X=350 are considered as representative positions. As shown in Figure 5(a), the composite illuminance unevenness ΔI(X) at positions L and R is approximately the same, that is, it is difficult to distinguish the difference in exposure conditions at positions L and R from the composite illuminance unevenness ΔI(X).

[0068] On the other hand, the spectral illuminance unevenness ΔI1(X) and ΔI2(X) shown in FIG. 5(b) differ from each other between positions L and R, and the spectral illuminance ratio I1(X) / I2(X) shown in FIG. 5(c) differs from each other between positions L and R. That is, the difference in exposure conditions at positions L and R can be determined from the spectral illuminance unevenness ΔI1(X) and ΔI2(X) and the spectral illuminance ratio I1(X) / I2(X). The resist CD changes depending on the difference in exposure conditions as shown in Figure 5(d), and therefore the resist CD obtained by the illumination optical system of the comparative example differs between positions L and R as shown in Figure 5(e).

[0069] As described above, in the illumination optical system of the comparative example, even if the combined illuminance is approximately the same at each position in the X direction on the illuminated surface, the spectral illuminance differs from one another, resulting in a change in the resist CD. In other words, in order to suppress the deterioration of the resist CD uniformity on the irradiated surface, it is not enough to simply consider the combined irradiance distribution on the irradiated surface. Therefore, the illumination optical system according to this embodiment suppresses the decrease in uniformity of the resist CD on the irradiated surface by taking into consideration the spectral illuminance distribution on the irradiated surface, as will be described in detail below.

[0070] FIG. 6 shows a block diagram of a plurality of control units 27a, 27b, 27c, 27d, 27e, 27f, 27g, 27h, 27i, and 27j included in the control unit 27. That is, the control unit 27 includes a control unit group (first control unit group) including a plurality of control units 27a to 27j, and a control unit group (second control unit group) including ten control units corresponding to each of the ten light source units included in the second light source 11b.

[0071] The plurality of control units 27a to 27j are configured to control the light output from the light source units 111a to 111j included in the first light source 11a, respectively. This allows the light output from each of the light source units 111a to 111j to be controlled independently, in other words, divided and controlled.

[0072] Specifically, the control units 27a to 27j are configured to control, for example, the power (current, voltage, input power, lighting power) and temperature of the plurality of LED elements 22 included in the light source units 111a to 111j, respectively. On the other hand, the relationship between the power supplied to the LED element 22 or the temperature of the LED element 22 and the intensity of the light output from the LED element 22 is not necessarily proportional to each other. Therefore, it is effective to store the relationship in advance in a predetermined storage device, and to read and use the relationship from the storage device as needed.

[0073] 7(a), (b), (c), (d), (e), (f), (g), (h), (i), and (j) show the spectral illuminance I1(X) at each position in the X direction on the irradiated surface when only the light source units 111a to 111j of the first light source 11a are made to emit light. That is, the vertical axis in each graph of Figures 7(a) to (j) indicates the magnitude of the Y-direction integrated illuminance obtained by integrating the illuminance of multiple lights having wavelength characteristics λ1 at each position in the Y direction where the position in the X direction on the irradiated surface is X.

[0074] Also, for example, FIG. 7A is acquired by turning on only the light source unit 111a while turning off the light source units 111b to 111j. 7(a) to 7(j) show the results when the light source units 111a to 111j are set to the same temperature and are turned on with the same light output.

[0075] As shown in Figures 7(a) to (j), the spectral illuminance distributions (positional distribution of spectral illuminance, positional dependence of spectral illuminance) on the irradiated surface caused by multiple lights having wavelength characteristics λ1 emitted from light source units 111a to 111j are different from each other. Here, the spectral illuminance I1(X) at each position in the X direction on the illuminated surface is expressed by the following formula (4).

number

[0076] In equation (4), i=1, 2, . . . , 10 correspond to the light source units 111a, 111b, . . . , 111j, respectively, and w1i indicates an adjustment coefficient for the light output from the plurality of LED elements 22 included in the i-th light source unit. Also I 1i (X) is the magnitude of the Y-direction integrated illuminance obtained by integrating the illuminance of multiple lights having wavelength characteristics λ1 from the i-th light source unit with a predetermined optical output and temperature at each position in the Y direction where the X-direction position is X on the irradiated surface.

[0077] As shown in equation (4), the spectral illuminance I1(X) at a predetermined position in the X direction on the irradiated surface is expressed as the spectral illuminance I 1i It can be expressed as a weighted sum of (X). As shown in FIGS. 7(a) to 7(j), the spectral illuminance I on the irradiated surface when the light source units 111a to 111j are turned on with the same optical output is 1i The distributions of (X) are different from each other.

[0078] Then, the light output of the i-th light source unit is adjusted to obtain the adjustment coefficient w 1i can be adjusted. That is, according to the formula (4), the adjustment coefficient w 1i By adjusting the spectral illuminance I1(X) at each position in the X direction on the irradiated surface, it is possible to adjust the spectral illuminance I1(X).

[0079] Specifically, for example, the spectral illuminances I 1_1 (X)~I 1_10 Each distribution of (X) is fitted with a polynomial function. As a result, the distribution of the spectral illuminance I1(X) from the first light source 11a can be expressed as a polynomial function using equation (4).

[0080] Furthermore, by expressing the target distribution of spectral illuminance I1(X) as a polynomial function, the difference between the acquired distribution of spectral illuminance I1(X) and the target distribution of spectral illuminance I1(X) can be expressed as the difference in the coefficients of each degree of the polynomial function. Then, the adjustment coefficient w is calculated based on the difference between the coefficients of each order. 1_1 Or even w 1_10 Adjust.

[0081] Here, adjusting the shape of the distribution of the spectral illuminance I1(X) on the illuminated surface by the illumination optical system 10 according to this embodiment does not mean scaling by uniformly multiplying all coefficients of each degree of the polynomial function by the same number. On the other hand, in the illumination optical system 10 according to this embodiment, the distribution of the spectral illuminance I1(X) on the illuminated surface may be scaled in addition to the shape adjustment.

[0082] Furthermore, even if the light source units 111a to 111j have the same configuration, the spectral illuminance I 1_1 (X)~I 1_10 The distribution of (X) differs from one another depending on the individual differences of the included LED elements 22, the positioning error of the light collecting portions 23, and the like. Therefore, the adjustment coefficient w 1i 7(a) to (j) at each position in the X direction on the irradiated surface. 1i Measure (X) in advance. Then, in order to form a predetermined distribution of the spectral illuminance I1(X) on the irradiated surface, an adjustment coefficient w 1i It is effective to adjust

[0083] Furthermore, the spectral illuminance I2(X) at each position in the X direction on the irradiated surface can be expressed by the following equation (5).

number

[0084] In equation (5), j=1, 2, . . . , 10 correspond to the 10 light source units included in the second light source 11b, and w 2j indicates an adjustment coefficient for the light output from each of the plurality of LED elements 22 included in the j-th light source unit.

[0085] Also I 2j (X) is the magnitude of the Y-direction integrated illuminance obtained by integrating the illuminance of multiple lights having wavelength characteristics λ2 from the j-th light source unit, which has a predetermined optical output and temperature, at each position in the Y direction where the X-direction position is X on the irradiated surface. Similarly to the first light source 11a, the adjustment coefficient w 2j By adjusting the above, it is possible to form a predetermined distribution of the spectral illuminance I2(X) on the surface to be illuminated.

[0086] Furthermore, the spectral characteristic R(X) at each position in the X direction on the illuminated surface is expressed by the following formula (6).

number

[0087] That is, the adjustment coefficient w 1i and w 2j By adjusting each of these, it is possible to form a predetermined distribution of the spectral characteristic R(X) on the surface to be illuminated. FIG. 8 is a flowchart showing the process of forming predetermined distributions of the spectral illuminances I1(X) and I2(X) on the illuminated surface by the illumination optical system 10 according to this embodiment.

[0088] When the process starts, first, the plurality of LED elements 22 included in the second light source 11b are not turned on, while only the plurality of LED elements 22 included in the first light source 11a are turned on (step S1). Next, the illuminance at each position on the irradiated surface is measured to obtain the spectral illuminance I1(X) (first illuminance distribution) at each position in the X direction on the irradiated surface (step S2).

[0089] FIG. 9(a) shows the spectral illuminance unevenness ΔI1(X) calculated using equation (2) from the spectral illuminance I1(X) acquired in step S2 at each position in the X direction on the irradiated surface. In step S2, the relative position of the sensor 7 provided on the substrate stage 6 with respect to the projection optical system 101 can be changed to measure the illuminance at each position on the surface to be illuminated.

[0090] Next, the plurality of LED elements 22 included in the first light source 11a are turned off, and the plurality of LED elements 22 included in the second light source 11b are turned on (step S3). Then, the illuminance at each position on the irradiated surface is measured to obtain I2(X) (second illuminance distribution) at each position in the X direction on the irradiated surface (step S4).

[0091] FIG. 9(b) shows the spectral illuminance unevenness ΔI2(X) calculated using equation (3) from the spectral illuminance I2(X) acquired in step S4 at each position in the X direction on the irradiated surface. That is, in steps S2 and S4, the distributions of the spectral illuminances I1(X) and I2(X) on the illuminated surface can be obtained separately from each other.

[0092] Next, based on the spectral illuminance I1(X) at each position in the X direction on the irradiated surface acquired in step S2, the adjustment coefficients w 1i (step S5, first control step, first adjustment step). This makes it possible to form a predetermined distribution (first target illuminance distribution) of the spectral illuminance I1(X) on the surface to be illuminated. FIG. 9(c) shows the spectral illuminance unevenness ΔI1(X) calculated using equation (2) from the spectral illuminance I1(X) adjusted in step S5 at each position in the X direction on the irradiated surface.

[0093] Next, based on the spectral illuminance I2(X) at each position in the X direction on the irradiated surface acquired in step S4, the adjustment coefficient w 2j is adjusted (step S6, second control step, second adjustment step). This makes it possible to form a predetermined distribution (second target irradiance distribution) of the spectral irradiance I2(X) on the surface to be illuminated.

[0094] FIG. 9(d) shows the spectral illuminance unevenness ΔI2(X) calculated using equation (3) from the spectral illuminance I2(X) adjusted in step S6 at each position in the X direction on the irradiated surface. The adjustment coefficient w in steps S5 and S6 1i and w 2j can be adjusted by, for example, changing the power input to the plurality of LED elements 22 included in each light source unit.

[0095] Finally, the spectral characteristics R(X) at each position in the X direction on the irradiated surface are adjusted to be optimal for the spectral sensitivity characteristics of the resist CD (step S7, third adjustment step), and the process ends. Specifically, in step S7, at least one of the spectral illuminances I1(X) and I2(X) is changed by a constant factor so as to adjust the spectral characteristic R(X) while maintaining the spectral illuminance unevenness ΔI1(X) and ΔI2(X), respectively, at each position in the X direction on the irradiated surface. More specifically, in step S7, the light output from each of the plurality of LED elements 22 included in at least one of the first light source 11a and the second light source 11b is changed uniformly.

[0096] FIG. 10(a) shows, as a schematic straight line, the spectral illuminances I1(X) and I2(X) at each position in the X direction on the irradiated surface adjusted in steps S5 and S6. FIG. 10(b) shows the spectral illuminance unevenness ΔI1(X) and ΔI2(X) at each position in the X direction on the irradiated surface acquired in steps S5 and S6.

[0097] FIG. 10(c) shows the spectral illuminances I1(X) and I2(X) at each position in the X direction on the irradiated surface adjusted in step S7, schematically indicated by straight lines. FIG. 10(d) shows the spectral illuminance unevenness ΔI1(X) and ΔI2(X) at each position in the X direction on the irradiated surface acquired in step S7.

[0098] In the example shown in FIG. 10(a), the adjustment coefficient w 1i and w 2j By performing the adjustment, the spectral characteristics R(X) at each position in the X direction on the irradiated surface are approximately 0.6 / approximately 0.4. In the example shown in FIG. 10(c), the optical output is adjusted in step S7 according to the spectral sensitivity characteristics of the resist CD, so that the spectral characteristics R(X) at each position in the X direction on the irradiated surface are approximately 0.5 / approximately 0.5. At this time, as shown in Figures 10(b) and (d), the adjustment of the light output in step S7 keeps the spectral illuminance unevenness ΔI1(X) and ΔI2(X) at each position in the X direction on the irradiated surface unchanged.

[0099] As described above, the relationship between the power supplied to the LED element 22 and the light output from the LED element 22 is not necessarily proportional to each other. Therefore, when adjusting the optical output by adjusting the power in step S7, it is effective to store the relationship in advance in a predetermined storage device and read out and use the relationship from the storage device.

[0100] In addition, since the light output from the LED element 22 also changes depending on the temperature of the LED element 22, when adjusting the light output from a specified LED element 22 in step S7, it is preferable not to change the temperature of the specified LED element 22. Alternatively, it is effective to store in advance in a predetermined storage device the relationship between the power supplied to the LED element 22, the temperature of the LED element 22, and the light output from the LED element 22, and then read out and use the relationship from the predetermined storage device.

[0101] In step S7, the light output from the LED element 22 can also be adjusted by adjusting the temperature of the LED element 22 instead of adjusting the power supplied to the LED element 22. On the other hand, the sensitivity of the light output of the LED element 22 to temperature changes is not necessarily constant, so it is effective to store the sensitivity in advance in a specified storage device and read out and use the relationship from the specified storage device. When adjusting the temperature of the LED element 22 in step S7, it is preferable to also adjust the power supplied to the LED element 22.

[0102] In the above exemplary step S7, the spectral characteristics R(X) change from approximately 0.6 / approximately 0.4 to approximately 0.5 / approximately 0.5 at each position in the X direction on the illuminated surface. That is, the composite illuminance I(X) does not change from about 0.6 + about 0.4 = about 1 to about 0.5 + about 0.5 = about 1.

[0103] However, without being limited to this, in step S7, processing may be performed to adjust the composite illuminance I(X) at each position in the X direction on the irradiated surface in accordance with the sensitivity characteristics of the resist CD. In other words, in step S7, a process may be performed to change the distribution of the synthetic illuminance I(X) on the irradiated surface to a predetermined distribution (target synthetic illuminance distribution) in accordance with the sensitivity characteristics of the resist CD.

[0104] FIG. 11 shows a front view of a light source unit 111a included in a first light source 11a provided in an illumination optical system according to a modification of this embodiment. The optical configuration of the illumination optical system according to the modification of this embodiment is the same as that of the illumination optical system 10 according to this embodiment, and therefore a description thereof will be omitted.

[0105] As described above, in the illumination optical system 10 according to this embodiment, the control units 27a to 27j are provided corresponding to the light source units 111a to 111j included in the first light source 11a, respectively. On the other hand, in the illumination optical system according to the modified example of this embodiment, a plurality of control units are associated with each of the light source units 111a to 111j included in the first light source 11a.

[0106] Specifically, the light source unit 111a is provided with eight rows, each row having 15 LED elements 22 connected in series, as shown in FIG. Control units 27k, 27m, 27n, 27o, 27p, 27q, 27r, and 27s are provided corresponding to the eight columns, respectively.

[0107] That is, in the illumination optical system according to the modified example of this embodiment, the control units 27k to 27s can independently control the power input to each row of the plurality of LED elements 22 provided in the light source unit 111a. Furthermore, the wavelengths of the LED elements 22 included in each column controlled by the control units 27k to 27s may be different from each other.

[0108] For example, the wavelengths of the LED elements 22 included in each column controlled by control units 27k, 27m, 27n, and 27o may be different from the wavelengths of the LED elements 22 included in each column controlled by control units 27p, 27q, 27r, and 27s. In this case, a plurality of LED elements 22 with wavelength characteristics λ1 can be provided in each row controlled by control units 27k, 27m, 27n and 27o, while a plurality of LED elements 22 with wavelength characteristics λ2 can be provided in each row controlled by control units 27p, 27q, 27r and 27s.

[0109] In this way, by providing multiple LED elements 22 with wavelength characteristics λ1 and λ2 in the light source units 111a to 111j included in the first light source 11a, there is no need to provide a wavelength synthesis section 16 in the illumination optical system in which the first light source 11a is provided. Furthermore, by each control unit independently controlling the corresponding column in each of the light source units 111a to 111j included in the first light source 11a, it is possible to adjust the distribution of the spectral illuminances I1(X) and I2(X) on the irradiated surface.

[0110] Furthermore, a plurality of LED elements 22 having predetermined wavelength characteristics that transmit through the dichroic mirror that forms the wavelength combining section 16 may be provided in at least one row in each of the light source units 111a to 111j included in the first light source 11a. Then, in each of the light source units 111a to 111j included in the first light source 11a, a plurality of LED elements 22 having different wavelength characteristics that transmit through the dichroic mirror may be provided in the remaining columns.

[0111] On the other hand, a plurality of LED elements 22 having predetermined wavelength characteristics that are reflected by the dichroic mirror may be provided in at least one row in each of a plurality of light source units included in the second light source 11b. Then, in each of the plurality of light source units included in the second light source 11b, a plurality of LED elements 22 having different wavelength characteristics that are reflected by the dichroic mirror may be provided in the remaining columns.

[0112] As described above, in the illumination optical system 10 according to this embodiment, the adjustment coefficient w 1_1 Or even w 1_10 are being adjusted. Similarly, the adjustment coefficient w for the light output from each of the ten light source units included in the second light source 11b is 2_1 Or even w 2_10 are being adjusted. As a result, in the illumination optical system 10 according to this embodiment, the distribution of the spectral illuminance I1(X) on the illuminated surface due to the light emitted from the first light source 11a and the distribution of the spectral illuminance I2(X) on the illuminated surface due to the light emitted from the second light source 11b are adjusted.

[0113] In other words, in the exposure apparatus 100 equipped with the illumination optical system 10 according to this embodiment, the surface of the substrate 5 can be exposed with a desired distribution of spectral illuminance I1(X) and a desired distribution of spectral illuminance I2(X). In other words, in an exposure apparatus 100 using a plurality of LED elements 22 that emit a plurality of light beams having different wavelengths, the degradation of the uniformity of the resist CD can be suppressed by appropriately correcting the spectral characteristics R(X) at each position within the substrate surface of the substrate 5.

[0114] In the process of forming predetermined distributions of the spectral illuminances I1(X) and I2(X) on the illuminated surface by the illumination optical system 10 according to this embodiment, the following steps (1), (2), (3), (4) and (5) are performed. (1) Measurement of the spectral illuminance I1(X) at each position in the X direction on the irradiated surface in order to perform steps (3) to (5) (2) Measuring the spectral illuminance I2(X) at each position in the X direction on the irradiated surface in order to perform steps (3) to (5). (3) Adjustment of the spectral characteristics R(X) at each position in the X direction on the irradiated surface (4) Adjustment of the spectral illuminance I1(X), the spectral illuminance I2(X), or the composite illuminance I1(X) + I2(X) at each position in the X direction on the irradiated surface (5) Adjustment coefficients w of each light source unit included in the first light source 11a and the second light source 11b for performing steps (3) and (4) 1i and w 2j Adjustment In the illumination optical system 10 according to this embodiment, the order of steps (1) to (5) may be changed as necessary, and multiple steps included in steps (1) to (5) may be performed simultaneously.

[0115] Furthermore, in the process of forming predetermined distributions of the spectral illuminances I1(X) and I2(X) on the illuminated surface by the illumination optical system 10 according to this embodiment, a sensor 7 equipped with an optical element capable of wavelength separation can be used. Such optical elements include, for example, dichroic mirrors, prisms, gratings, and wavelength filters.

[0116] By using the sensor 7 including such an optical element, steps S1 and S3 can be performed simultaneously, and steps S2 and S4 can be performed simultaneously in the flowchart shown in FIG. That is, with the plurality of LED elements 22 included in the first light source 11a and the plurality of LED elements 22 included in the second light source 11b turned on, the spectral illuminances I1(X) and I2(X) at each position in the X direction on the irradiated surface can be simultaneously obtained.

[0117] Furthermore, by using the sensor 7 including such an optical element, it becomes unnecessary to turn off the LED elements 22 included in the first light source 11a in step S3. That is, in step S3, while each of the plurality of LED elements 22 included in the first light source 11a is turned on, each of the plurality of LED elements 22 included in the second light source 11b is turned on, thereby enabling spectroscopic processing in the sensor 7.

[0118] Furthermore, when using a sensor 7 that does not include an optical element as described above, it is not necessary to turn off the multiple LED elements 22 included in the second light source 11b in step S1 and the multiple LED elements 22 included in the first light source 11a in step S3. For example, in step S3, each of the plurality of LED elements 22 included in the first light source 11a is turned on, and in step S4, the composite illuminance I1(X)+I2(X) is obtained at each position in the X direction on the illuminated surface. Then, the spectral illuminance I2(X) can be obtained by subtracting the spectral illuminance I1(X) obtained in step S2 from the composite illuminance I1(X)+I2(X) obtained in step S4 for each position in the X direction on the irradiated surface. In this case, however, the spectral sensitivity characteristics of the sensor 7 must be taken into consideration.

[0119] In the illumination optical system 10 according to this embodiment, when forming predetermined distributions of the spectral illuminances I1(X) and I2(X) on the illuminated surface, the adjustment coefficients w 1i and w 2j are being adjusted. In this case, the predetermined distribution may be formed by turning off some of the LED elements 22 included in each of the first light source 11a and the second light source 11b.

[0120] In the illumination optical system 10 according to this embodiment, for example, ten light source units 111a to 111j are provided in the first light source 11a, but the number of light source units provided in the first light source 11a is not limited to this. Furthermore, in the illumination optical system 10 according to this embodiment, the LED elements 22 are used in each of the first light source 11a and the second light source 11b, but this is not limiting and solid-state light source elements such as LD elements may also be used. Furthermore, although the illumination optical system 10 according to this embodiment is provided in an exposure apparatus 100 having a single projection optical system 101, it is not limited to this and can also be provided in an exposure apparatus having multiple projection optical systems for projecting images onto multiple regions on the substrate surface of the substrate.

[0121] [Second embodiment] FIG. 12 shows a schematic cross-sectional view of an illumination optical system 110 according to the second embodiment. The illumination optical system 110 according to this embodiment has the same configuration as the illumination optical system 10 according to the first embodiment, except that an imaging system 18 and a variable field stop 41 are newly provided. Therefore, the same components are given the same reference numerals and their explanations are omitted.

[0122] In the illumination optical system 10 according to the first embodiment, the distribution of the spectral illuminances I1(X) and I2(X) on the irradiated surface is adjusted by adjusting the light output of the plurality of LED elements 22 provided in each of the first light source 11a and the second light source 11b. However, while this adjustment can be easily performed, there is a risk that it may cause a large difference in the usage environment, for example, a difference in deterioration rate, between the multiple LED elements 22 provided in each of the first light source 11a and the second light source 11b.

[0123] That is, by making this adjustment, some of the LED elements 22 among the plurality of LED elements 22 provided in each of the first light source 11a and the second light source 11b will reach the end of their life earlier than the remaining LED elements 22. Therefore, in the illumination optical system 110 of this embodiment, in addition to adjusting the light output of the multiple LED elements 22 provided in each of the first light source 11a and the second light source 11b, the shape of the opening formed in the variable field diaphragm 41 is also adjusted. This makes it possible to adjust the distribution of the spectral illuminances I1(X) and I2(X) on the irradiated surface while suppressing differences in the usage environments between the multiple LED elements 22 provided in each of the first light source 11a and the second light source 11b.

[0124] In the illumination optical system 110 according to this embodiment, as shown in FIG. 12, light passing through the aperture stop 14 is first focused by the second condenser lens 15 onto a mask conjugate plane that is optically conjugate to the mask plane of the mask 19 with respect to the imaging system 18. The light that has passed through the mask conjugate plane is then focused onto the mask surface of the mask 19 by the imaging system 18 .

[0125] The variable field diaphragm 41 has an opening whose shape is adjustable and through which light from each of the first light source 11a and the second light source 11b passes, and is disposed at the position of the mask conjugate plane. It should be noted that while variable field diaphragm 41 cannot independently adjust the spectral illuminance distribution for each of a plurality of wavelengths on the surface to be illuminated, it can adjust the composite illuminance distribution for a plurality of wavelengths. Therefore, in the illumination optical system 110 according to this embodiment, the shape of the opening of the variable field diaphragm 41 is adjusted to adjust the combined illuminance I1(X)+I2(X) at each position in the X direction on the illuminated surface.

[0126] Furthermore, the spectral illuminance I1(X) at each position in the X direction on the illuminated surface is adjusted by adjusting the light output of each of the plurality of LED elements 22 included in the first light source 11a. Then, the spectral illuminance I2(X) at each position in the X direction on the illuminated surface is adjusted by adjusting the light output of each of the plurality of LED elements 22 included in the second light source 11b. By carrying out the above-mentioned adjustments, which are shared between them, it is possible to adjust both the combined illuminance distribution and the spectral characteristic distribution for each of the wavelength characteristics λ1 and λ2 on the illuminated surface.

[0127] 13(a) and (b) show front views of an exemplary variable field stop 41 provided in the illumination optical system 110 according to this embodiment. In the variable field diaphragm 41 shown in FIGS. 13(a) and 13(b), an arc-shaped opening is formed by a plate-like component 44. The plate-like parts 44 are deformed by displacing the plurality of adjustment mechanisms 42 that are in contact with the plate-like parts 44, thereby making it possible to adjust the opening width 43 at each position in a predetermined direction.

[0128] When the illumination optical system 110 according to this embodiment is mounted on the exposure apparatus 100, the variable field stop 41 is positioned so that the predetermined direction corresponds to the non-scanning direction, while the direction parallel to the aperture width 43 corresponds to the scanning direction. This makes it possible to adjust the illuminance at each position on the surface of the substrate 5 in the non-scanning direction.

[0129] 13(c) and (d) show front views of another exemplary variable field diaphragm 41 provided in the illumination optical system 110 according to this embodiment. In the variable field diaphragm 41 shown in FIGS. 13(c) and (d), a rectangular opening is formed by a plate-like component 54. The plate-like parts 54 are deformed by displacing the plurality of adjustment mechanisms 42 that are in contact with the plate-like parts 54, thereby making it possible to adjust the opening width 43 at each position in a predetermined direction.

[0130] 13(e) and (f) show front views of yet another exemplary variable field diaphragm 41 provided in the illumination optical system 110 according to this embodiment. In the variable field diaphragm 41 shown in FIGS. 13(e) and 13(f), a rectangular opening is formed by a plurality of plate-shaped light blocking members 45. By displacing each of the plurality of plate-shaped light blocking members 45, the opening width 43 at each position in a predetermined direction can be adjusted.

[0131] FIG. 14 is a flowchart showing the process of forming predetermined distributions of the spectral illuminances I1(X) and I2(X) on the illuminated surface by the illumination optical system 110 according to this embodiment. When the process starts, first, the plurality of LED elements 22 included in the second light source 11b are not turned on, while only the plurality of LED elements 22 included in the first light source 11a are turned on (step S11). Next, the illuminance at each position on the irradiated surface is measured to obtain the spectral illuminance I1(X) at each position in the X direction on the irradiated surface (step S12).

[0132] Next, the plurality of LED elements 22 included in the first light source 11a are turned off, and the plurality of LED elements 22 included in the second light source 11b are turned on (step S13). Then, the illuminance at each position on the illuminated surface is measured to obtain I2(X) at each position in the X direction on the illuminated surface (step S14).

[0133] FIG. 15(a) shows the spectral illuminance unevenness ΔI1(X) calculated using equation (2) from the spectral illuminance I1(X) acquired in step S12 at each position in the X direction on the irradiated surface. FIG. 15(a) also shows the spectral illuminance unevenness ΔI2(X) calculated using equation (3) from the spectral illuminance I2(X) acquired in step S14 at each position in the X direction on the irradiated surface.

[0134] Next, for each position in the X direction on the irradiated surface, the differences (first difference and second difference) between the spectral irradiance I1(X) acquired in step S12 and the spectral irradiance I2(X) acquired in step S14 and their respective target values ​​are calculated (step S15, calculation step). Then, by adjusting the shape of the opening formed in the variable field diaphragm 41, the common component of the difference between the spectral illuminances I1(X) and I2(X) calculated in step S15 is adjusted for each position in the X direction on the irradiated surface (step S16).

[0135] FIG. 15(b) shows the spectral illuminance unevenness ΔI1(X) and ΔI2(X) calculated from the spectral illuminances I1(X) and I2(X) after adjusting the common component in step S16 at each position in the X direction on the irradiated surface. Finally, the adjustment coefficients w of the light source units included in the first light source 11a and the second light source 11b are 1i and w 2j By adjusting the difference between the spectral illuminances I1(X) and I2(X) calculated in step S15, the remaining components of the difference are adjusted (step S17). Then, the process ends. FIG. 15(c) shows the spectral illuminance unevenness ΔI1(X) and ΔI2(X) calculated from the spectral illuminances I1(X) and I2(X) after adjusting the remaining components in step S17 at each position in the X direction on the irradiated surface.

[0136] In the illumination optical system 110 according to this embodiment, the distribution of the spectral illuminances I1(X) and I2(X) on the illuminated surface can be partially adjusted by using the variable field diaphragm 41. As a result, the adjustment coefficient w between the light source units included in the first light source 11a and the second light source 11b is 1i and w 2j The difference can be reduced. Therefore, it is possible to suppress the occurrence of differences in the usage environment between the plurality of LED elements 22 provided in each of the first light source 11a and the second light source 11b.

[0137] As described above, in the illumination optical system 110 according to this embodiment, the difference between the distribution of the spectral illuminance I1(X) on the illuminated surface due to the light emitted from the first light source 11a and the distribution of the spectral illuminance I2(X) due to the light emitted from the second light source 11b and the target distribution is obtained. The common component of the difference is adjusted by changing the shape of the opening formed in the variable field stop 41.

[0138] The remaining components of the difference other than the common component are calculated using the adjustment coefficients w 1_1 Or even w 1_10 are being adjusted. In addition, an adjustment coefficient w for the light output from each of the ten light source units included in the second light source 11b is set. 2_1 Or even w 2_10 are being adjusted.

[0139] As a result, in the illumination optical system 110 according to this embodiment, the distribution of the spectral illuminance I1(X) on the illuminated surface due to the light emitted from the first light source 11a and the distribution of the spectral illuminance I2(X) on the illuminated surface due to the light emitted from the second light source 11b are adjusted. In other words, in the exposure apparatus 100 equipped with the illumination optical system 110 according to this embodiment, the surface of the substrate 5 can be exposed with a desired distribution of spectral illuminance I1(X) and a desired distribution of spectral illuminance I2(X). In other words, in an exposure apparatus 100 using a plurality of LED elements 22 that emit a plurality of light beams having different wavelengths, the degradation of the uniformity of the resist CD can be suppressed by appropriately correcting the spectral characteristics R(X) at each position within the substrate surface of the substrate 5.

[0140] In the process of forming predetermined distributions of the spectral illuminances I1(X) and I2(X) on the illuminated surface by the illumination optical system 110 according to this embodiment, the following steps (1), (2), (3), (4), (5), and (6) are performed. (1) Measurement of the spectral illuminance I1(X) at each position in the X direction on the irradiated surface in order to perform steps (3) to (6) (2) Measuring the spectral illuminance I2(X) at each position in the X direction on the irradiated surface to perform steps (3) to (6) (3) Adjustment of the spectral characteristics R(X) at each position in the X direction on the irradiated surface (4) Adjustment of the spectral illuminance I1(X), the spectral illuminance I2(X), or the composite illuminance I1(X) + I2(X) at each position in the X direction on the irradiated surface (5) Adjusting the shape of the opening formed in the variable field diaphragm 41 to correct the common component of the difference between the target values ​​of the spectral illuminances I1(X) and I2(X) at each position in the X direction on the irradiated surface in steps (3) and (4). (6) Adjustment coefficients w of each light source unit included in each of the first light source 11a and the second light source 11b for correcting the remaining components of the difference between the target values ​​of the spectral illuminances I1(X) and I2(X) at each position in the X direction on the irradiated surface in steps (3) and (4). 1i and w 2j Adjustment In the illumination optical system 110 according to this embodiment, the order of steps (1) to (6) may be changed as needed, and multiple steps included in steps (1) to (6) may be performed simultaneously.

[0141] In the illumination optical system 110 according to this embodiment, the variable field stop 41 is used to correct the common component, but the member for correcting the common component is not limited to this.

[0142] [Third embodiment] In the illumination optical system 10 according to the first embodiment and the illumination optical system 110 according to the second embodiment, the distributions of the spectral illuminances I1(X) and I2(X) on the illuminated surface are corrected to be uniform.

[0143] However, even if exposure is performed on the substrate 5 using an exposure apparatus 100 equipped with such an illumination optical system 10 or illumination optical system 110, there is a risk that the error in the resist CD will increase depending on external factors such as drawing errors of the pattern formed on the mask 19 and process characteristics. Therefore, in the illumination optical system according to the third embodiment, the distribution of the spectral illuminances I1(X) and I2(X) on the illuminated surface is adjusted to correct the increase in the error in the resist CD, thereby improving the uniformity of the resist CD.

[0144] The illumination optical system according to this embodiment has the same optical configuration as the illumination optical system 10 according to the first embodiment, so the same members are given the same reference numerals and descriptions thereof will be omitted. Furthermore, as shown in FIG. 5(d), the resist CD changes in accordance with the change in the spectral characteristic R(X). Therefore, when adjusting the distributions of the spectral illuminances I1(X) and I2(X) on the irradiated surface to correct the increase in the resist CD error, it is preferable not to change the distribution of the spectral characteristic R(X).

[0145] FIG. 16 shows the change in resist CD when the combined illuminance I1(X)+I2(X) is changed in the illumination optical system according to this embodiment. Specifically, in FIG. 16, the horizontal axis represents the composite illuminance I1(X)+I2(X) and the reference composite illuminance {I1(X)+I2(X)} t The difference between the reference composite illuminance {I1(X)+I2(X)} tThe vertical axis shows the ratio of the resist CD to the target CD, CD / CD t is shown.

[0146] In FIG. 16, the synthetic illuminance I1(X)+I2(X) is the reference synthetic illuminance {I1(X)+I2(X)} t The register CD is set as the target CD. That is, in the illumination optical system according to this embodiment, the distribution of the combined illuminance I1(X)+I2(X) on the illuminated surface is adjusted to correct the increase in the resist CD error, thereby improving the uniformity of the resist CD.

[0147] FIG. 17 is a flowchart showing the process of forming predetermined distributions of the spectral illuminances I1(X) and I2(X) and the composite illuminance I1(X)+I2(X) on the illuminated surface by an exposure apparatus 100 equipped with an illumination optical system according to this embodiment. When the process starts, first, the plurality of LED elements 22 included in the second light source 11b are not turned on, while only the plurality of LED elements 22 included in the first light source 11a are turned on (step S21).

[0148] Next, the illuminance at each position on the irradiated surface is measured to obtain the spectral illuminance I1(X) at each position in the X direction on the irradiated surface (step S22). Next, the plurality of LED elements 22 included in the first light source 11a are turned off, and the plurality of LED elements 22 included in the second light source 11b are turned on (step S23). Then, the illuminance at each position on the illuminated surface is measured to obtain I2(X) at each position in the X direction on the illuminated surface (step S24).

[0149] FIG. 18(a) shows the spectral illuminance unevenness ΔI1(X) calculated using equation (2) from the spectral illuminance I1(X) acquired in step S22 at each position in the X direction on the irradiated surface. FIG. 18(a) also shows the spectral illuminance unevenness ΔI2(X) calculated using equation (3) from the spectral illuminance I2(X) acquired in step S24 at each position in the X direction on the irradiated surface.

[0150] FIG. 18(b) shows the composite illuminance unevenness ΔI(X) calculated using equation (1) from the spectral illuminance I1(X) acquired in step S22 and the spectral illuminance I2(X) acquired in step S24 at each position in the X direction on the irradiated surface. FIG. 18(c) shows the spectral characteristic unevenness ΔR(X) calculated from the spectral illuminance I1(X) acquired in step S22 and the spectral illuminance I2(X) acquired in step S24 at each position in the X direction on the irradiated surface.

[0151] Here, the spectral characteristic unevenness ΔR(X) can be expressed as the following equation (7) based on the above equation (6).

number

[0152] The denominator on the right side of equation (7) represents the average value of I1(X) / I2(X). Next, the difference between the spectral illuminance unevenness ΔI1(X) calculated in step S22 and ΔI2(X) calculated in step S24 at each position in the X direction on the irradiated surface is calculated (step S25). Then, the adjustment coefficients w of the light source units included in the first light source 11a and the second light source 11b are adjusted so as to reduce the difference at each position in the X direction on the illuminated surface calculated in step S25. 1i and w 2j is adjusted (step S26).

[0153] FIG. 18(d) shows the spectral illuminance unevenness ΔI1(X) and ΔI2(X) adjusted in step S26 at each position in the X direction on the irradiated surface. FIG. 18(e) shows the synthetic illuminance unevenness ΔI(X) adjusted in step S26 at each position in the X direction on the illuminated surface. FIG. 18(f) shows the spectral characteristic unevenness ΔR(X) adjusted in step S26 at each position in the X direction on the illuminated surface.

[0154] By performing the adjustments in step S26 (fourth adjustment process, fifth adjustment process), the distribution of spectral illuminance unevenness ΔI1(X) and the distribution of spectral illuminance unevenness ΔI2(X) on the irradiated surface are corrected to have approximately the same shape, as shown in Figure 18(d). Then, by performing the adjustment in step S26, the spectral characteristic unevenness ΔR(X) becomes approximately 0 at each position in the X direction on the illuminated surface, as shown in FIG. 18(f).

[0155] Next, at each position in the X direction on the surface to be irradiated, the magnitude of the spectral characteristic R(X) is adjusted in accordance with the sensitivity characteristics of the resist so as not to change the spectral characteristic unevenness ΔR(X) (step S27). Note that step S27 may be omitted if necessary.

[0156] Next, the substrate 5 is exposed in the exposure apparatus 100 using the illumination optical system according to this embodiment adjusted as described above, and the difference between the resist CD and the target CD at each position in the X direction on the substrate surface of the substrate 5 is calculated (step S28, exposure process). Then, based on the difference (pattern line width distribution) at each position on the substrate surface of substrate 5 calculated in step S28, the composite illuminance unevenness ΔI(X) at each position in the X direction on the irradiated surface is adjusted (step S29), and the process ends. That is, in step S29, the synthetic illuminance I(X) on the illuminated surface is changed to a predetermined distribution (target synthetic illuminance distribution).

[0157] FIG. 18(g) shows the spectral illuminance unevenness ΔI1(X) and ΔI2(X) adjusted in step S29 at each position in the X direction on the irradiated surface. FIG. 18(h) shows the synthetic illuminance unevenness ΔI(X) adjusted in step S29 at each position in the X direction on the illuminated surface. FIG. 18(i) shows the spectral characteristic unevenness ΔR(X) adjusted in step S29 at each position in the X direction on the illuminated surface.

[0158] That is, in step S29, the composite illuminance unevenness ΔI(X) at each position in the X direction on the irradiated surface is changed as shown in Figures 18(e) and (h) so as to reduce the difference between the resist CD and the target CD at each position on the substrate surface of the substrate 5. On the other hand, even after the adjustment in step S29, the distribution of the spectral illuminance unevenness ΔI1(X) and the distribution of the spectral illuminance unevenness ΔI2(X) on the irradiated surface have approximately the same shape as each other, as shown in Figure 18(g). Even after the adjustment in step S29, the spectral characteristic unevenness ΔR(X) at each position in the X direction on the illuminated surface is approximately 0, as shown in FIG. 18(i).

[0159] As described above, in the illumination optical system according to this embodiment, the adjustment coefficients w for the light output from each of the ten light source units 111a to 111j included in the first light source 11a are 1_1 Or even w 1_10 are being adjusted. Similarly, the adjustment coefficient w for the light output from each of the ten light source units included in the second light source 11b is 2_1 Or even w 2_10 are being adjusted.

[0160] Next, exposure is performed on the substrate 5 in the exposure apparatus 100 equipped with the illumination optical system according to this embodiment that has been adjusted in this way. Then, based on the difference between the resist CD and the target CD at each position on the substrate surface of the exposed substrate 5, the adjustment coefficient w 1_1 Or even w 1_10 and the above adjustment coefficient w 2_1 Or even w 2_10 is being adjusted again.

[0161] As a result, in the illumination optical system according to this embodiment, the distribution of the spectral illuminance I1(X) on the illuminated surface due to the light emitted from the first light source 11a and the distribution of the spectral illuminance I2(X) on the illuminated surface due to the light emitted from the second light source 11b are adjusted. Furthermore, the distribution of the combined illuminance I(X) on the illuminated surface by the light emitted from the first light source 11a and the light emitted from the second light source 11b is adjusted.

[0162] In other words, in the exposure apparatus 100 equipped with the illumination optical system according to this embodiment, the surface of the substrate 5 can be exposed with a desired distribution of synthetic illuminance I(X), a desired distribution of spectral illuminance I1(X), and a desired distribution of spectral illuminance I2(X). In other words, in an exposure apparatus 100 using multiple LED elements 22 that emit multiple lights having different wavelengths, the deterioration of the uniformity of the resist CD can be suppressed by appropriately correcting the composite illuminance I(X) at each position within the substrate surface of the substrate 5.

[0163] In the process of forming predetermined distributions of the spectral illuminances I1(X) and I2(X) and the composite illuminance I1(X)+I2(X) on the illuminated surface by the illumination optical system according to this embodiment, the following steps (1) to (9) are performed. (1) Measurement of the spectral illuminance I1(X) at each position in the X direction on the irradiated surface in order to perform steps (3) to (5) (2) Measuring the spectral illuminance I2(X) at each position in the X direction on the irradiated surface in order to perform steps (3) to (5). (3) Adjustment of the spectral characteristics R(X) at each position in the X direction on the irradiated surface (4) Adjustment of the spectral illuminance I1(X), the spectral illuminance I2(X), or the composite illuminance I1(X) + I2(X) at each position in the X direction on the irradiated surface (5) Adjustment coefficients w of each light source unit included in the first light source 11a and the second light source 11b for performing steps (3) and (4) 1i and w 2j Adjustment (6) Exposure of the substrate 5 in the exposure apparatus 100 equipped with the illumination optical system according to this embodiment for performing step (7) (7) Obtaining the difference between the resist CD and the target CD at each position in the X direction on the substrate surface of the substrate 5 in order to perform step (8). (8) Adjustment of the combined illuminance I1(X) + I2(X) at each position in the X direction on the irradiated surface (9) Adjustment coefficients w of each light source unit included in each of the first light source 11a and the second light source 11b for performing step (8) 1i and w 2j Adjustment In the illumination optical system according to this embodiment, a plurality of steps included in steps (1) to (9) may be performed simultaneously as necessary.

[0164] The illumination optical system according to this embodiment may have the same optical configuration as the illumination optical system 110 according to the second embodiment. At this time, the shape of the opening formed in the variable field diaphragm 41 in the above steps (5) and (9) may be adjusted. Furthermore, if the predetermined distributions of the spectral illuminances I1(X) and I2(X) and the composite illuminance I1(X)+I2(X) on the irradiated surface are not formed even after performing the above steps (1) to (9), at least one of the above steps (1) to (9) may be performed again.

[0165] [Fourth embodiment] In the illumination optical system according to the third embodiment, the distribution of the spectral characteristic R(X) on the illuminated surface is made uniform, while the distribution of the synthetic illuminance I(X) is made non-uniform, thereby suppressing an increase in the error of the resist CD. On the other hand, as shown in FIG. 5(d), the resist CD changes in accordance with the change in the spectral characteristic R(X).

[0166] Therefore, in the illumination optical system according to the fourth embodiment, the distribution of the spectral characteristic R(X) on the illuminated surface is adjusted to suppress an increase in the resist CD error due to external factors such as drawing errors of the pattern formed on the mask 19 and process characteristics. The illumination optical system according to this embodiment has the same optical configuration as the illumination optical system 10 according to the first embodiment, so the same members are given the same reference numerals and descriptions thereof will be omitted.

[0167] As shown in FIG. 16, the resist CD changes in response to changes in the combined illuminance I(X). Therefore, when adjusting the distributions of the spectral illuminances I1(X) and I2(X) on the irradiated surface to correct the increase in the resist CD error, it is preferable not to change the distribution of the composite illuminance I(X).

[0168] FIG. 19 is a flowchart showing the process of forming predetermined distributions of the spectral illuminances I1(X) and I2(X) on the surface to be illuminated in exposure apparatus 100 equipped with the illumination optical system according to this embodiment. When the process starts, first, the plurality of LED elements 22 included in the second light source 11b are not turned on, while only the plurality of LED elements 22 included in the first light source 11a are turned on (step S31).

[0169] Next, the illuminance at each position on the irradiated surface is measured to obtain the spectral illuminance I1(X) at each position in the X direction on the irradiated surface (step S32). Next, the plurality of LED elements 22 included in the first light source 11a are turned off, and the plurality of LED elements 22 included in the second light source 11b are turned on (step S33). Then, the illuminance at each position on the illuminated surface is measured to obtain I2(X) at each position in the X direction on the illuminated surface (step S34).

[0170] FIG. 20(a) shows the spectral illuminance unevenness ΔI1(X) calculated using equation (2) from the spectral illuminance I1(X) acquired in step S32 at each position in the X direction on the irradiated surface. FIG. 20(a) also shows the spectral illuminance unevenness ΔI2(X) calculated using equation (3) from the spectral illuminance I2(X) acquired in step S34 at each position in the X direction on the irradiated surface.

[0171] FIG. 20(b) shows the composite illuminance unevenness ΔI(X) calculated using equation (1) from the spectral illuminance I1(X) acquired in step S32 and the spectral illuminance I2(X) acquired in step S34 at each position in the X direction on the irradiated surface. FIG. 20(c) shows the spectral characteristic unevenness ΔR(X) calculated using equation (7) from the spectral illuminance I1(X) acquired in step S32 and the spectral illuminance I2(X) acquired in step S34 at each position in the X direction on the irradiated surface.

[0172] Next, based on the spectral illuminance I1(X) at each position in the X direction on the irradiated surface acquired in step S32, the adjustment coefficients w 1i is adjusted (step S35). Then, based on the spectral illuminance I2(X) at each position in the X direction on the irradiated surface acquired in step S34, the adjustment coefficient w 2j is adjusted (step S36).

[0173] FIG. 20(d) shows the spectral illuminance unevenness ΔI1(X) and ΔI2(X) adjusted in steps S35 and S36 at each position in the X direction on the irradiated surface. FIG. 20(e) shows the synthetic illuminance unevenness ΔI(X) adjusted in steps S35 and S36 at each position in the X direction on the illuminated surface. FIG. 20(f) shows the spectral characteristic unevenness ΔR(X) adjusted in steps S35 and S36 at each position in the X direction on the irradiation surface.

[0174] Next, at each position in the X direction on the surface to be irradiated, the magnitude of the spectral characteristic R(X) is adjusted in accordance with the sensitivity characteristic of the resist (step S37). Note that step S37 may be omitted if necessary.

[0175] Next, the substrate 5 is exposed in the exposure apparatus 100 using the illumination optical system according to this embodiment adjusted as described above, and the difference between the resist CD and the target CD at each position in the X direction on the substrate surface of the substrate 5 is calculated (step S38, exposure process). Then, based on the difference at each position on the surface of the substrate 5 calculated in step S38, the spectral characteristic unevenness ΔR(X) at each position in the X direction on the irradiated surface is adjusted (step S39), and the process ends. That is, in step S39, the spectral characteristic R(X) on the surface to be illuminated is changed to a predetermined distribution (target spectral characteristic distribution).

[0176] FIG. 20(g) shows the spectral illuminance unevenness ΔI1(X) and ΔI2(X) adjusted in step S39 at each position in the X direction on the irradiated surface. FIG. 20(h) shows the synthetic illuminance unevenness ΔI(X) adjusted in step S39 at each position in the X direction on the illuminated surface. FIG. 20(i) shows the spectral characteristic unevenness ΔR(X) adjusted in step S39 at each position in the X direction on the illuminated surface.

[0177] That is, in step S39, the spectral characteristic unevenness ΔR(X) at each position in the X direction on the irradiated surface changes as shown in Figures 20(f) and (i) so as to reduce the difference between the resist CD and the target CD at each position on the substrate surface of the substrate 5. In step S39, the spectral illuminance unevenness ΔI1(X) and ΔI2(X) at each position in the X direction on the irradiated surface changes as shown in FIGS. 20(d) and 20(g). On the other hand, even after the adjustment in step S39, the synthetic illuminance unevenness ΔI(X) at each position in the X direction on the illuminated surface is approximately 0 as shown in FIG. 20(h).

[0178] As described above, in the illumination optical system according to this embodiment, the adjustment coefficients w for the light output from each of the ten light source units 111a to 111j included in the first light source 11a are 1_1 Or even w 1_10 are being adjusted. Similarly, the adjustment coefficient w for the light output from each of the ten light source units included in the second light source 11b is 2_1 Or even w 2_10 are being adjusted.

[0179] Next, exposure is performed on the substrate 5 in the exposure apparatus 100 equipped with the illumination optical system according to this embodiment that has been adjusted in this way. Then, based on the difference between the resist CD and the target CD at each position on the substrate surface of the exposed substrate 5, the adjustment coefficient w 1_1 Or even w 1_10 and the above adjustment coefficient w 2_1 Or even w 2_10 is being adjusted again.

[0180] As a result, in the illumination optical system according to this embodiment, the distribution of the spectral illuminance I1(X) on the illuminated surface due to the light emitted from the first light source 11a and the distribution of the spectral illuminance I2(X) on the illuminated surface due to the light emitted from the second light source 11b are adjusted. Furthermore, the distribution of the spectral characteristics R(X) on the illuminated surface due to the light emitted from the first light source 11a and the light emitted from the second light source 11b is adjusted.

[0181] In other words, in the exposure apparatus 100 equipped with the illumination optical system according to this embodiment, the surface of the substrate 5 can be exposed with a desired distribution of the spectral characteristic R(X), a desired distribution of the spectral illuminance I1(X), and a desired distribution of the spectral illuminance I2(X). In other words, in an exposure apparatus 100 using a plurality of LED elements 22 that emit a plurality of light beams having different wavelengths, the degradation of the uniformity of the resist CD can be suppressed by appropriately correcting the spectral characteristics R(X) at each position within the substrate surface of the substrate 5.

[0182] In the process of forming predetermined distributions of the spectral illuminances I1(X) and I2(X) on the illuminated surface by the illumination optical system according to this embodiment, the following steps (1), (2), (3), (4), (5), (6), (7), (8), and (9) are performed. (1) Measurement of the spectral illuminance I1(X) at each position in the X direction on the irradiated surface in order to perform steps (3) to (5) (2) Measuring the spectral illuminance I2(X) at each position in the X direction on the irradiated surface in order to perform steps (3) to (5). (3) Adjustment of the spectral characteristics R(X) at each position in the X direction on the irradiated surface (4) Adjustment of the spectral illuminance I1(X), the spectral illuminance I2(X), or the composite illuminance I1(X) + I2(X) at each position in the X direction on the irradiated surface (5) Adjustment coefficients w of each light source unit included in the first light source 11a and the second light source 11b for performing steps (3) and (4) 1i and w 2j Adjustment (6) Exposure of the substrate 5 in the exposure apparatus 100 equipped with the illumination optical system according to this embodiment for performing step (7) (7) Obtaining the difference between the resist CD and the target CD at each position in the X direction on the substrate surface of the substrate 5 in order to perform step (8). (8) Adjustment of the spectral characteristics R(X) at each position in the X direction on the irradiated surface (9) Adjustment coefficients w of each light source unit included in each of the first light source 11a and the second light source 11b for performing step (8) 1i and w 2j Adjustment In the illumination optical system according to this embodiment, a plurality of steps included in steps (1) to (9) may be performed simultaneously as necessary.

[0183] The illumination optical system according to this embodiment may have the same optical configuration as the illumination optical system 110 according to the second embodiment. At this time, the shape of the opening formed in the variable field diaphragm 41 in the above steps (5) and (9) may be adjusted. Furthermore, if the predetermined distributions of the spectral illuminances I1(X) and I2(X) on the irradiated surface are not formed even after performing the above steps (1) to (9), at least one of the above steps (1) to (9) may be performed again.

[0184] [Production method] Next, a method for manufacturing an article using exposure apparatus 100 equipped with an illumination optical system according to any one of the first to fourth embodiments will be described.

[0185] The products manufactured here include semiconductor devices, display devices, color filters, optical components, and MEMS (Micro Electro Mechanical Systems). For example, a semiconductor device is manufactured through a pre-process for forming a circuit pattern on a substrate 5 and a post-process including a processing step for completing the circuit chip formed in the pre-process as a product.

[0186] The pre-processing includes an exposure process in which a substrate 5 coated with a photosensitive agent (resist) is exposed using an exposure apparatus 100 equipped with an illumination optical system according to any one of the first to fourth embodiments, and a development process in which the photosensitive agent exposed in the exposure process is developed. Then, a circuit pattern is formed on the substrate 5 by carrying out an etching process, an ion implantation process, etc. using the developed photosensitive agent pattern as a mask.

[0187] By repeating these steps of exposure, development, etching, etc., a circuit pattern consisting of multiple layers is formed on the substrate 5. In the post-process, dicing is performed on the substrate 5 on which the circuit pattern has been formed, and chip mounting, bonding and inspection processes are carried out.

[0188] A display device is manufactured through a process of forming a transparent electrode. The process of forming a transparent electrode includes a step of applying a photosensitive agent to a glass substrate 5 on which a transparent conductive film has been vapor-deposited, and a step of exposing the substrate 5 on which the photosensitive agent has been applied using an exposure apparatus 100 equipped with an illumination optical system according to any one of the first to fourth embodiments. The step of forming the transparent electrode also includes a step of developing the exposed photosensitive agent.

[0189] According to the method for manufacturing an article according to this embodiment, it is possible to manufacture an article with higher quality and higher productivity than conventional methods. Although the preferred embodiments have been described above, the present invention is not limited to these embodiments and various modifications and changes are possible within the scope of the gist thereof.

[0190] The disclosure of this embodiment includes the following configurations and methods. (Configuration 1) An illumination optical system comprising: a first light source that emits first light having a first wavelength; a second light source that emits second light having a second wavelength different from the first wavelength; and a control unit that performs at least one of a first control step of controlling the first light source so that a first illuminance distribution by the first light on an irradiated surface becomes a first target illuminance distribution; and a second control step of controlling the second light source so that a second illuminance distribution by the second light on an irradiated surface becomes a second target illuminance distribution. (Configuration 2) The illumination optical system described in Configuration 1, wherein the first light source is formed from a first light source unit group including at least one light source unit, the second light source is formed from a second light source unit group including at least one light source unit, the control unit is formed from a first control unit group including at least one control unit corresponding to each of the at least one light source unit included in the first light source unit group, and a second control unit group including at least one control unit corresponding to each of the at least one light source unit included in the second light source unit group, the first control process includes a first adjustment process of adjusting at least one of the input power and the temperature of at least one light source unit included in the first light source unit group, and the second control process includes a second adjustment process of adjusting at least one of the input power and the temperature of at least one light source unit included in the second light source unit group. (Configuration 3) The illumination optical system described in Configuration 2 is characterized in that the control unit performs a third adjustment process of changing at least one of the illuminance by the first light and the illuminance by the second light at each position on the illuminated surface by a constant multiple so that the first illuminance distribution and the second illuminance distribution do not change. (Configuration 4) The illumination optical system according to Configuration 3, wherein the control unit performs a third adjustment step so that the combined illuminance distribution of the first light and the second light on the illuminated surface does not change. (Configuration 5) An illumination optical system according to Configuration 2, comprising a variable field diaphragm through which first light and second light pass and having an aperture whose shape is adjustable, wherein the control unit performs a calculation step of calculating a first difference between the first illuminance distribution and the first target illuminance distribution and a second difference between the second illuminance distribution and the second target illuminance distribution, and a step of adjusting the shape of the aperture based on the common component of the first difference and the second difference calculated by the calculation step. (Configuration 6) An illumination optical system described in Configuration 5, characterized in that the first adjustment step includes a step of adjusting at least one of the input power and the temperature of at least one light source unit included in the first light source unit group based on a component other than the common component included in the first difference calculated by the calculation step, and the second adjustment step includes a step of adjusting at least one of the input power and the temperature of at least one light source unit included in the second light source unit group based on a component other than the common component included in the second difference calculated by the calculation step. (Configuration 7) An illumination optical system described in any one of configurations 2 to 6, characterized in that each light source unit has at least one row of multiple solid-state light source elements connected in series by wiring for inputting power. (Configuration 8) An illumination optical system described in Configuration 7, characterized in that each control unit is configured to independently control at least one of the input power and the temperature in each of at least one row provided in the corresponding light source unit. (Configuration 9) An illumination optical system described in any one of configurations 1 to 8, characterized in that the control unit performs a process of controlling at least one of the first light source and the second light source so that the combined illuminance distribution of the first light and the second light on the illuminated surface becomes a target combined illuminance distribution. (Configuration 10) An illumination optical system according to any one of configurations 1 to 9, characterized in that it includes a dichroic mirror that transmits one of the first light emitted from the first light source and the second light emitted from the second light source and reflects the other. (Configuration 11) The illumination optical system according to any one of configurations 1 to 10, further comprising an optical element that focuses the first light and the second light on the illuminated surface. (Configuration 12) An illumination optical system according to any one of configurations 1 to 11, characterized in that it comprises an integrator that forms a plurality of secondary light sources using the first light emitted from the first light source and the second light emitted from the second light source. (Configuration 13) An exposure apparatus that projects an image of a pattern of an original onto a substrate and exposes the substrate, characterized in that it is equipped with an illumination optical system described in any one of configurations 1 to 12 that illuminates the original. (Structure 14) An exposure apparatus according to Structure 13, wherein the first light source is formed from a first light source unit group including at least one light source unit, the second light source is formed from a second light source unit group including at least one light source unit, the control unit is formed from a first control unit group including at least one control unit corresponding to each of the at least one light source unit included in the first light source unit group, and a second control unit group including at least one control unit corresponding to each of the at least one light source unit included in the second light source unit group, the first control step includes a fourth adjustment step of adjusting at least one of the input power and the temperature of at least one light source unit included in the first light source unit group so that the first illuminance distribution becomes a first target illuminance distribution, and the second control step includes a fifth adjustment step of adjusting at least one of the input power and the temperature of at least one light source unit included in the second light source unit group so that the second illuminance distribution becomes a second target illuminance distribution that is identical to the first target illuminance distribution. (Configuration 15) The exposure apparatus described in Configuration 14, characterized in that the control unit performs an exposure process of exposing a substrate with a first illuminance distribution and a second illuminance distribution adjusted by performing at least one of the fourth adjustment process and the fifth adjustment process, and a process of controlling at least one of the first light source and the second light source based on the line width distribution of a pattern formed on the substrate surface of the substrate exposed by the exposure process, so that the combined illuminance distribution of the first light and the second light on the irradiated surface becomes a target combined illuminance distribution, so that the spectral characteristic distribution of the first light and the second light on the irradiated surface does not change. (Structure 16) An exposure apparatus according to Structure 13, characterized in that the first light source is formed from a first light source unit group including at least one light source unit, the second light source is formed from a second light source unit group including at least one light source unit, the control unit is formed from a first control unit group including at least one control unit corresponding to each of the at least one light source unit included in the first light source unit group, and a second control unit group including at least one control unit corresponding to each of the at least one light source unit included in the second light source unit group, the first control process includes a first adjustment process of adjusting at least one of the input power and temperature of at least one light source unit included in the first light source unit group, and the second control process includes a second adjustment process of adjusting at least one of the input power and temperature of at least one light source unit included in the second light source unit group. (Configuration 17) The exposure apparatus described in Configuration 16, characterized in that the control unit performs an exposure process of exposing a substrate with a first illuminance distribution and a second illuminance distribution adjusted by performing at least one of a first adjustment process and a second adjustment process, and a process of controlling at least one of the first light source and the second light source based on the line width distribution of a pattern formed on the substrate surface of the substrate exposed by the exposure process, so that the spectral characteristic distribution of the first light and the second light on the irradiated surface becomes a target spectral characteristic distribution, so that the combined illuminance distribution of the first light and the second light on the irradiated surface does not change. (Method 1) A method for manufacturing an article, comprising the steps of exposing a substrate using an exposure apparatus equipped with an illumination optical system described in any one of configurations 1 to 12 or the exposure apparatus described in any one of configurations 13 to 17, and developing the exposed substrate, wherein the method manufactures an article from the developed substrate. (Method 2) An illumination method for illuminating an illuminated surface using an illumination optical system having a first light source that emits first light having a first wavelength and a second light source that emits second light having a second wavelength different from the first wavelength, the illumination method comprising at least one of a first control step of controlling the first light source so that a first illuminance distribution due to the first light on the illuminated surface becomes a first target illuminance distribution, and a second control step of controlling the second light source so that a second illuminance distribution due to the second light on the illuminated surface becomes a second target illuminance distribution. [Explanation of symbols]

[0191] 10 Illumination optical system 11a First light source 11b Second light source 27 Control Unit 29 Calculation unit (control unit)

Claims

1. a first light source that emits a first light having a first wavelength; a second light source that emits second light having a second wavelength different from the first wavelength; a control unit that performs at least one of a first control step of controlling the first light source so that a first illuminance distribution by the first light on the illuminated surface becomes a first target illuminance distribution, and a second control step of controlling the second light source so that a second illuminance distribution by the second light on the illuminated surface becomes a second target illuminance distribution; An illumination optical system comprising:

2. the first light source is formed from a first light source unit group including at least one light source unit, the second light source is formed from a second light source unit group including at least one light source unit, the control unit is formed of a first control unit group including at least one control unit corresponding to each of the at least one light source units included in the first light source unit group, and a second control unit group including at least one control unit corresponding to each of the at least one light source units included in the second light source unit group, the first control step includes a first adjustment step of adjusting at least one of an input power and a temperature of at least one light source unit included in the first light source unit group, 2. The illumination optical system according to claim 1, wherein the second control step includes a second adjustment step of adjusting at least one of input power and temperature of at least one light source unit included in the second light source unit group.

3. 3. The illumination optical system according to claim 2, wherein the control unit performs a third adjustment step of changing at least one of the illuminance by the first light and the illuminance by the second light at each position on the illuminated surface by a constant multiple so that the first illuminance distribution and the second illuminance distribution do not change.

4. 4. The illumination optical system according to claim 3, wherein the control unit performs the third adjustment step so that a combined illuminance distribution of the first light and the second light on the illuminated surface does not change.

5. a variable field diaphragm through which the first light and the second light pass and having an opening whose shape is adjustable; The control unit a calculating step of calculating a first difference between the first illuminance distribution and the first target illuminance distribution and a second difference between the second illuminance distribution and the second target illuminance distribution; adjusting the shape of the opening based on the common component of the first difference and the second difference calculated in the calculating step; 3. The illumination optical system according to claim 2, wherein the following is performed:

6. the first adjustment step includes a step of adjusting at least one of the input power and the temperature of the at least one light source unit included in the first light source unit group based on a component other than the common component included in the first difference calculated in the calculation step, 6. The illumination optical system according to claim 5, wherein the second adjustment step includes a step of adjusting at least one of the input power and the temperature of the at least one light source unit included in the second light source unit group based on a component other than the common component included in the second difference calculated by the calculation step.

7. 3. The illumination optical system according to claim 2, wherein each light source unit has at least one row of a plurality of solid-state light source elements connected in series by wiring for inputting electric power.

8. 8. The illumination optical system according to claim 7, wherein each control unit is configured to independently control at least one of input power and temperature in each of the at least one row provided in a corresponding light source unit.

9. 2. The illumination optical system according to claim 1, wherein the control unit performs a step of controlling at least one of the first light source and the second light source so that a combined illuminance distribution of the first light and the second light on the illuminated surface becomes a target combined illuminance distribution.

10. 2. The illumination optical system according to claim 1, further comprising a dichroic mirror that transmits one of the first light emitted from the first light source and the second light emitted from the second light source and reflects the other.

11. 2. The illumination optical system according to claim 1, further comprising an optical element that focuses the first light and the second light on the illuminated surface.

12. 2. The illumination optical system according to claim 1, further comprising an integrator that forms a plurality of secondary light sources with the first light emitted from the first light source and the second light emitted from the second light source.

13. An exposure apparatus that projects an image of a pattern of an original onto a substrate and exposes the substrate, An exposure apparatus comprising the illumination optical system according to claim 1 for illuminating the original.

14. the first light source is formed from a first light source unit group including at least one light source unit, the second light source is formed from a second light source unit group including at least one light source unit, the control unit is formed of a first control unit group including at least one control unit corresponding to each of the at least one light source units included in the first light source unit group, and a second control unit group including at least one control unit corresponding to each of the at least one light source units included in the second light source unit group, the first control step includes a fourth adjustment step of adjusting at least one of input power and temperature of at least one light source unit included in the first light source unit group so that the first illuminance distribution becomes the first target illuminance distribution, 14. The exposure apparatus according to claim 13, wherein the second control step includes a fifth adjustment step of adjusting at least one of input power and temperature in at least one light source unit included in the second light source unit group so that the second irradiance distribution becomes the same as the first target irradiance distribution.

15. The control unit an exposure step of exposing the substrate with the first illuminance distribution and the second illuminance distribution adjusted by performing at least one of the fourth adjustment step and the fifth adjustment step; a step of controlling at least one of the first light source and the second light source based on a line width distribution of the pattern formed on the substrate surface of the substrate exposed in the exposure step so that a combined illuminance distribution of the first light and the second light on the illuminated surface becomes a target combined illuminance distribution so that a spectral characteristic distribution of the first light and the second light on the illuminated surface does not change; 15. The exposure apparatus according to claim 14, wherein the exposure apparatus performs the following steps.

16. the first light source is formed from a first light source unit group including at least one light source unit, the second light source is formed from a second light source unit group including at least one light source unit, the control unit is formed of a first control unit group including at least one control unit corresponding to each of the at least one light source units included in the first light source unit group, and a second control unit group including at least one control unit corresponding to each of the at least one light source units included in the second light source unit group, the first control step includes a first adjustment step of adjusting at least one of an input power and a temperature of at least one light source unit included in the first light source unit group, 14. The exposure apparatus according to claim 13, wherein the second control step includes a second adjustment step of adjusting at least one of an input power and a temperature of at least one light source unit included in the second light source unit group.

17. The control unit an exposure step of exposing the substrate with the first illuminance distribution and the second illuminance distribution adjusted by performing at least one of the first adjustment step and the second adjustment step; a step of controlling at least one of the first light source and the second light source based on a line width distribution of the pattern formed on the substrate surface of the substrate exposed in the exposure step so that a spectral characteristic distribution by the first light and the second light on the illuminated surface becomes a target spectral characteristic distribution so that a combined illuminance distribution by the first light and the second light on the illuminated surface does not change; 17. The exposure apparatus according to claim 16, wherein the exposure apparatus performs the following steps.

18. a step of exposing a substrate by an exposure apparatus comprising the illumination optical system according to any one of claims 1 to 12 or the exposure apparatus according to any one of claims 13 to 17; developing the exposed substrate; Including, A method for manufacturing an article, comprising manufacturing an article from the developed substrate.

19. 1. An illumination method for illuminating an illumination target surface using an illumination optical system including a first light source that emits first light having a first wavelength and a second light source that emits second light having a second wavelength different from the first wavelength, the illumination method comprising: an illumination method comprising at least one of a first control step of controlling the first light source so that a first illuminance distribution due to the first light on the illuminated surface becomes a first target illuminance distribution, and a second control step of controlling the second light source so that a second illuminance distribution due to the second light on the illuminated surface becomes a second target illuminance distribution.

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