JP2020095219A - Exposure apparatus, exposure method and method for manufacturing article - Google Patents

Abstract

To provide an exposure apparatus which is advantageous for improving transfer performance to transfer a pattern onto a substrate.SOLUTION: The exposure apparatus exposes a substrate by use of light in a plurality of wavelength regions including a first wavelength region and a second wavelength region, and the apparatus includes: an illumination optical system for illuminating a mask with the above light; and a projection optical system for projecting an image of a pattern of the mask onto the substrate. The illumination optical system forms an intensity distribution described below on a pupil plane of the illumination optical system. The intensity distribution comprises: a first intensity distribution including light in at least the first wavelength region, in which the intensity ratio of the light in the first wavelength region to the light in the second wavelength region is a first intensity ratio; and a second intensity distribution including light in at least the second wavelength region, in which the intensity ratio of the light in the first wavelength region to the light in the second wavelength is a second intensity ratio different from the first intensity ratio; and the intensity distribution formed on the pupil plane has a four-time rotational symmetry.SELECTED DRAWING: Figure 7

Description

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

The projection exposure apparatus is an apparatus that transfers a pattern formed on a mask (original plate) onto a substrate (plate), illuminates the mask through an illumination optical system, and forms an image of the pattern on the mask through the projection optical system. Project on the substrate. The illumination optical system illuminates the optical integrator with the light from the light source, and generates a secondary light source on the exit surface of the optical integrator corresponding to the pupil plane of the illumination optical system. The secondary light source is formed of a light emitting region having a predetermined shape and a predetermined size. Further, the light emitting region forming the secondary light source corresponds to the angular distribution of light that illuminates each point of the mask. Note that the exposure apparatus also includes a maskless exposure apparatus that does not require a mask.

In the exposure apparatus, there is a super resolution technology (RET) as a technology for improving the transfer performance for a fine pattern. As one of the RETs, modified illumination that optimizes the angular distribution of light that illuminates each point on the mask is known.

In Patent Document 1, as a modified illumination, a focus position in a first exposure process using an inner concentric circular light emitting region and a focus position in a second exposure process using an outer concentric circular light emitting region are set to different positions. Technology is proposed. In Patent Document 2, in order to reduce a line width difference between patterns in a plurality of directions (line width non-uniformity due to pattern direction differences), it contributes to image formation of a pattern having a relatively low image contrast. There has been proposed a technique for shifting the wavelength of the light emitting region existing in the direction to the short wavelength side.

JP-A-2000-252199 JP, 2018-54992, A

The technique disclosed in Patent Document 1 can improve the transfer performance of a pattern in which an isolated pattern and a line and space (LS) pattern are mixed by using modified illumination that is one of RET. However, the technique disclosed in Patent Document 1 does not consider performing modified illumination suitable for each of a plurality of wavelength bands included in broadband illumination light (broadband illumination light). Therefore, when broadband illumination light is used, the effect of sufficiently improving the transfer performance for a fine pattern cannot be obtained.

Although the technique disclosed in Patent Document 2 uses broadband illumination light, it is a technique for solving the line width nonuniformity due to the pattern direction difference, and is a technique for improving transfer performance for a fine pattern, that is, RET. is not. In order to obtain the effect of improving the transfer performance for a fine pattern, it is essential that the direction difference of the light emitting region corresponds to the direction difference of the pattern. The technique disclosed in Patent Document 2 is another technique different in the problem to be solved from the present invention that proposes one of RET.

The present invention has been made in view of the above problems of the conventional art, and an exemplary object of the present invention is to provide an exposure apparatus that is advantageous for improving the transfer performance of transferring a pattern onto a substrate.

In order to achieve the above object, an exposure apparatus according to one aspect of the present invention is an exposure apparatus that exposes a substrate using light in a plurality of wavelength bands including a first wavelength band and a second wavelength band, An illumination optical system that illuminates the mask with the light, and a projection optical system that projects an image of the pattern of the mask onto the substrate, the illumination optical system including at least the light in the first wavelength range, A first intensity distribution in which the intensity ratio of the light in the first wavelength range and the light in the second wavelength range is a first intensity ratio; and light in the first wavelength range including at least light in the second wavelength range And a second intensity distribution in which the intensity ratio of the light in the second wavelength range is a second intensity ratio different from the first intensity ratio, and the intensity distribution has four-fold rotational symmetry. In addition, it is formed on the pupil plane of the illumination optical system.

Further objects and other aspects of the present invention will be made clear by the embodiments described below with reference to the accompanying drawings.

According to the present invention, for example, it is possible to provide an exposure apparatus that is advantageous for improving the transfer performance of transferring a pattern onto a substrate.

It is a schematic diagram showing the composition of the exposure device as one side of the present invention. It is a figure for demonstrating the structure of an illumination optical system. It is a figure for demonstrating the conventional modified illumination. It is a figure for demonstrating the conventional modified illumination. It is a figure for explaining the modified lighting in a 1st embodiment. It is a figure for explaining the modified lighting in a 1st embodiment. It is a figure for explaining the modified lighting in a 1st embodiment. It is a figure for demonstrating the effect which improves the transfer performance to a fine pattern by the modified illumination of 1st Embodiment. It is a figure for explaining the modified lighting in a 1st embodiment. It is a figure for explaining the modified lighting in a 1st embodiment. It is a figure for demonstrating the structure of a light source and an illumination optical system. It is a flow chart for explaining an exposure method.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In each drawing, the same reference numerals are given to the same members, and duplicate description will be omitted.

FIG. 1 is a schematic diagram showing a configuration of an exposure apparatus 100 according to one aspect of the present invention. The exposure apparatus 100 is a lithographic apparatus that exposes a substrate using light including a plurality of wavelength ranges and transfers a pattern onto the substrate. The exposure apparatus 100 is used for manufacturing a flat panel display, a liquid crystal display element, a semiconductor element, a MEMS, etc., and is particularly suitable as a flat panel display exposure apparatus. The exposure apparatus 100 arranges an illumination optical system 10 for illuminating a mask (original plate) 9 which is a surface to be illuminated with light from a light source, and an image of a pattern formed on the mask 9 at a position optically conjugate with the mask 9. It has a projection optical system 11 for projecting onto the printed substrate 12 and a stage 38.

In the present embodiment, the projection optical system 11 is a reflection optical system that includes mirrors 32, 34, and 36 and reflects light in the order of the mirrors 32, 34, 36, 34, and 32, and forms an image of the pattern of the mask 9. The image is projected on the substrate 12 at the same size. The projection optical system 11 is a reflection optical system in which the chromatic aberration of the light from the light source is smaller than that of the refractive optical system, and is therefore suitable when using broadband light (broadband illumination light) including a plurality of wavelength bands. The stage 38 is a stage that holds the substrate 12 and is movable.

<First Embodiment>
FIG. 2 is a diagram for explaining the configuration of the illumination optical system 10 in this embodiment. However, in FIG. 2, the projection optical system 11 is illustrated in a simplified manner. As shown in FIG. 2, the illumination optical system 10 includes a condenser mirror 2, a condenser lens 5, a fly-eye lens 7, a condenser lens 8, and an aperture stop 61. An optical system (not shown) for shaping the light from the light source 1 is arranged in the optical path from the condenser lens 5 to the mask 9 so that the cross section of the light has a predetermined shape and a predetermined size. ing.

The light source 1 is a light source that emits broadband light (light in which lights of a plurality of wavelengths are mixed). In this embodiment, the light source 1 includes a mercury lamp that emits ultraviolet light, and emits light in which bright lines (i-line (365 nm), g-line (405 nm), h-line (436 nm)) having a plurality of peak wavelengths are mixed. To do. The light source 1 includes a light emitting unit in the vicinity of the first focus 3 of the condenser mirror 2, and the condenser mirror 2 condenses the light emitted from the light source 1 to the second focal point 4.

The condenser lens 5 shapes the light condensed at the first focus 4 into parallel light. The light shaped by the condenser lens 5 enters the incident surface 7 a of the fly-eye lens 7. The fly-eye lens 7 is an optical integrator including a plurality of optical elements, specifically, a plurality of minute lenses. The fly-eye lens 7 forms a secondary light source on the exit surface 7b (light exit surface) from the light that has entered the entrance surface 7a (light entrance surface). The light emitted from the fly-eye lens 7 illuminates the mask 9 in a superimposed manner via the plurality of condenser lenses 8.

A measuring unit (not shown) is arranged on the stage 38. The measuring unit includes a sensor capable of measuring the shape and light intensity of the secondary light source formed on the exit surface 7b of the fly-eye lens 7, for example, a CCD sensor.

Ring illumination (ring-shaped distribution), which is one of the super-resolution techniques (RET), and modified illumination (oblique incidence illumination) such as quadrupole illumination are effective for improving resolution. The modified illumination having a predetermined light emitting region (intensity distribution) can be realized by the aperture stop 61 arranged on the exit surface 7b of the fly-eye lens 7 (optical integrator) corresponding to the pupil plane of the illumination optical system 10.

Here, it is assumed that the pattern pitch of the mask 9 (cycle of pattern repetition) is P, the wavelength of light illuminating the mask 9 (exposure wavelength) is λ, and the numerical aperture of the projection optical system 11 is NA. In this case, by illuminating the mask 9 with the modified illumination including the light emitting region I including the illumination angle σ _c defined by the following equation (1), it is possible to suppress the decrease in image contrast due to defocus.

In Expression (1), the illumination angle σ _c corresponds to the distance from the origin (pupil radius) when represented by the pupil coordinates set on the pupil plane of the illumination optical system 10.

In the conventional modified illumination, for example, in the case of a semiconductor exposure apparatus, the wavelength λ is used as a single value because the spectrum of the light emitted from the light source is narrow. On the other hand, a flat panel display exposure apparatus uses broadband illumination in which the spectrum of light emitted from a light source is wide. However, in the prior art, even in a flat panel display exposure apparatus, as in the semiconductor exposure apparatus, the light emission area of the modified illumination is set to a single wavelength λ (for example, the wavelength having the largest intensity or the center of gravity obtained by weighting the intensity). Wavelength).

In the present embodiment, for the different first wavelength range λ1 and second wavelength range λ2 included in the broadband illumination, different first emission regions I1 and second emission regions I2 suitable for the respective wavelength ranges are used, so that Improve the transfer performance of various patterns. In other words, the present embodiment is conventional in that the light of the first wavelength region λ1 and the light of the second wavelength region λ2 which are different from each other are used as the illumination light for each of the first light emitting region I1 and the second light emitting region I2. Different from technology.

With respect to the narrow annular zone known as a conventional modified illumination method, the present embodiment has an effect of suppressing a decrease in illuminance and a decrease in productivity. In addition, since the present embodiment uses a wider annular zone (width) than a narrow annular zone, uneven illuminance due to non-uniformity of illumination intensity formed by the fly-eye lens 7 is reduced. The present embodiment can improve the transfer performance even for a pattern having a pitch other than the specific pitch P, as compared with narrow ring illumination having a narrow ring width.

In the present embodiment, in order to improve the resolution by shortening the wavelength in the related art, long-wavelength light is not completely blocked and long-wavelength is used in a specific light emitting region, so that depth of focus (DOF) is achieved. Is maintained. Furthermore, in the present embodiment, since long-wavelength light is not completely blocked, it is possible to suppress a decrease in illuminance (a decrease in productivity).

<Example 1>
As a comparative example, a conventional modified illumination will be described with reference to FIGS. 3 and 4. FIG. 3 shows a graph in which the illumination angle σ _c shown in Expression (1) is plotted. In FIG. 3, a light emitting region I0 indicated by a horizontal line represents conventional modified illumination, specifically, annular illumination with an inner σ of 0.45 and an outer σ of 0.90. The exposure wavelength is 335 nm or more and 475 nm or less as shown by the wavelength range λ0, and is broadband illumination corresponding to the spectrum of the i-line, g-line and h-line of the mercury lamp. The light emitting region I0 includes the illumination angle σ _c in the wavelength region λ0, and such modified illumination has the effect of suppressing the decrease in image contrast due to defocus, as described above.

FIG. 4 is a diagram showing the conventional modified illumination shown in FIG. 3 in pupil coordinates of the illumination optical system. As shown in FIG. 4, the conventional modified illumination is an annular illumination with an inner σ of 0.45 and an outer σ of 0.90, and the exposure wavelength is 335 nm or more and 475 nm or less.

The modified illumination in this embodiment will be described below. FIG. 5 shows a graph in which the illumination angle σ _c shown in Expression (1) is plotted. Different first emission regions I1 and second emission regions I2 are used for the first wavelength region λ1 and the second wavelength region λ2 that are included in the broadband illumination and are different from each other. The first light emitting region I1 and the second light emitting region I2 are distinguished by the pupil radius on the pupil plane of the illumination optical system 10.

The first wavelength range λ1 is a wavelength range of 335 nm or more and 395 nm or less, and is a wavelength range corresponding to the i-line spectrum of the mercury lamp that is the light source 1. The first light emitting region I1 including the light in the first wavelength region λ1 is an annular illumination (an annular shape distribution) having an inner σ of 0.45 and an outer σ of 0.90. As described above, the first light emitting region I1 includes at least light in the first wavelength range λ1, and the intensity ratio between the light in the first wavelength range λ1 and the light in the second wavelength range λ2 is the first intensity ratio. The intensity distribution. The first light emitting region I1 includes the illumination angle σ _c in the first wavelength region λ1, and the modified illumination has the effect of suppressing the decrease in image contrast due to defocus, as described above.

The second wavelength range λ2 is a wavelength range from 395 nm to 475 nm and is a wavelength range corresponding to the g-line and h-line spectra of the mercury lamp that is the light source 1. The second light emitting region I2 including the light in the second wavelength region λ2 is an annular illumination (an annular shape distribution) having an inner σ of 0.70 and an outer σ of 0.90. As described above, the second light emitting region I2 includes at least light in the second wavelength region λ2, and the intensity ratio between the light in the first wavelength region λ1 and the light in the second wavelength region λ2 is different from the first intensity ratio. It is the 2nd intensity distribution used as 2 intensity ratio. The second light emitting region I2 includes an illumination angle σ _c with respect to a part of the second wavelength range λ2, and the modified illumination has an effect of suppressing a decrease in image contrast due to defocus, as described above. ..

As described above, the modified illumination of the present embodiment includes the first light emitting region I1 and the second light emitting region I2, and the first light emitting region I1 and the second light emitting region I2 have a diameter of the pupil plane of the illumination optical system 10. The size is different. Further, the modified illumination of the present embodiment is a non-luminous region D in FIG. The wavelength range corresponding to the g-line and the h-line having an inner σ of 0.45 and an outer σ of 0.70 is cut. The non-light emitting area D is an area that is not used as illumination light. The non-light emitting area D is preferably an area different from the illumination angle σ _c . However, the non-light emission area D, not must not contain an illumination angle sigma _c, it may include an illumination angle sigma _c at a wavelength of part of the wavelength region. To cut the wavelength range in the non-light emitting area D, a wavelength filter may be provided in the illumination optical system 10. For example, as shown in FIG. 2, the illumination optical system 10 includes a wavelength file 63 that forms a first light emitting region I1 and a second light emitting region I2 by transmitting or blocking light in a specific wavelength region among a plurality of wavelength regions. It may be arranged in the vicinity of the pupil plane.

The modified illumination of the present embodiment shown in FIG. 5 can also be expressed as the modified illumination shown in FIG. The modified illumination shown in FIG. 6 will be described. The first wavelength range λ1 is a wavelength range of 335 nm or more and 395 nm or less, and is a wavelength range corresponding to the i-line spectrum of the mercury lamp that is the light source 1. The first light emitting region I1 including the light in the first wavelength range λ1 is an annular illumination having an inner σ of 0.45 and an outer σ of 0.70. The second wavelength range λ2 is a wavelength range of 335 nm or more and 475 nm or less, and is a wavelength range corresponding to the i-line, g-line, and h-line spectra of the mercury lamp that is the light source 1. The second light emitting region I2 including the light in the second wavelength range λ2 is an annular illumination having an inner σ of 0.70 and an outer σ of 0.90. As described above, in the division of the plurality of wavelength ranges, the wavelengths included in both the first wavelength range λ1 and the second wavelength range λ2 may exist within the wavelength range. In other words, the first wavelength band λ1 and the second wavelength band λ2 may partially overlap each other.

FIG. 7 is a diagram showing the modified illumination of this embodiment shown in FIGS. 5 and 6 in the pupil coordinates of the illumination optical system. Referring to FIG. 7, the wavelength range inside the hatched zone (inner σ is 0.45, outer σ is 0.70) is 335 nm or more and 395 nm or less, which corresponds to the i-line, g-line and The h line is cut. The wavelength range outside the ring zone (inner σ is 0.45 and outer σ is 0.90) shown in black is 335 nm or more and 475 nm or less, and corresponds to the i-line, g-line, and h-line. As shown in FIG. 7, in the present embodiment, the modified illumination (intensity distribution) including the first light emitting region I1 (first intensity distribution) and the second light emitting region I2 (second intensity distribution) is generated by the modified illumination. It is formed on the pupil plane of the illumination optical system 10 so as to be rotationally symmetrical.

The effect of improving the transfer performance for a fine pattern by the modified illumination according to the present embodiment will be described with reference to FIG. FIG. 8 is a comparison of transfer performance between the conventional technique (FIG. 3) and Example 1 (FIG. 7) of the present embodiment for a line and space (LS) pattern having a line width of 1.5 μm and a pitch (cycle) of 3 μm. FIG. The numerical aperture (NA) of the projection optical system is 0.10. The LS pattern contains 7 lines and evaluates the center line. The DOF is evaluated by defocusing so that the line width of the center line is -10%.

As shown in FIG. 8, in Example 1 of the present embodiment, the image contrast is improved from 0.53 to 0.56, and the DOF of the resist image is from 47.5 μm to 70. It has been improved to 0 μm. In addition, in Example 1 of the present embodiment, the side wall angle of the resist image is improved from 69.4 degrees to 70.9 degrees as compared with the related art. Although not shown in FIG. 8, MEEF (Mask Error Enhancement Factor) is also improved as the image contrast is improved. These results show that the transfer performance corresponding to a fine pattern can be improved by using light of different wavelength bands for each light emitting region as in the present embodiment. In Example 1 of the present embodiment, the g-line and the h-line are not used inside the ring zone (inner σ is 0.45 and outer σ is 0.70). 74% of the total.

Specifically, in Example 1 of the present embodiment, the large improvement in DOF includes the effect of using the annular zone with σ of 0.70 or more. Light in the annular zone with σ of 0.70 or more has the effect of reducing the line width of the central line of the LS pattern with defocusing. Therefore, since the increase in the line width of the LS pattern due to defocus is suppressed by the light in the annular zone where σ is 0.70 or more, the DOF can be greatly improved. As described above, the DOF of the LS pattern can be improved by using the light emitting region having a large σ.

<Example 2>
Modified illumination in Example 2 of the exemplary embodiment will be described with reference to FIG. 9. FIG. 9 shows a graph in which the illumination angle σ _c shown in Expression (1) is plotted. As shown in FIG. 9, in the modified illumination of the second embodiment, in addition to the non-luminous region D1 corresponding to the inner σ of the long wavelength region, the non-luminous region D2 corresponding to the outer σ of the short wavelength region exists. The non-light emitting areas D1 and D2 are areas different from the illumination angle σ _c .

The first wavelength range λ1 is a wavelength range of 335 nm or more and 420 nm or less. The first light emitting region I1 including the light in the first wavelength range λ1 is an annular illumination having an inner σ of 0.45 and an outer σ of 0.70. The second long region λ2 is a wavelength region of 395 nm or more and 475 nm or less. The second light emitting region I2 including the light in the second wavelength range λ2 is an annular illumination having an inner σ of 0.70 and an outer σ of 0.90. Light in the wavelength range of 395 nm or more and 420 nm or less is included in both the first light emitting region I1 and the second light emitting region I2 in an overlapping manner. As shown in the non-light emitting region D2, by cutting the short wavelength region of the outer σ, it is possible to obtain the effect of improving the transfer performance of the line located at the end of the LS pattern in the pitch direction.

Consider the case where the modified illumination shown in FIG. 9 is represented by the pupil coordinates of the illumination optical system, as in FIG. 7. In this case, in FIG. 7, the wavelength range inside the hatched zone (inner σ is 0.45 and outer σ is 0.70) is 335 nm or more and 420 nm or less, and the outside of the zone shown in black (inner The wavelength range in which σ is 0.45 and the outer σ is 0.90) is 395 nm or more and 475 nm or less.

<Example 3>
If the pattern (or transfer pattern) of the mask 9 does not have a clear pitch P, the area that the light emitting area should include cannot be obtained from the equation (1). In such a case, it is advisable to set the light emitting region to include an illumination angle with a high diffracted light intensity. Specifically, the first light emitting region I1 including the light in the first wavelength range λ1 is a region where the diffracted light intensity (intensity distribution) D of the mask pattern with respect to the first wavelength range λ1 shown in the following formula (2) is large. Good to include.

In Expression (2), mask represents the pattern of the mask 9, and F represents the Fourier transform.

The expression (1) in the case where the pattern of the mask 9 has a clear pitch P corresponds to a region where the diffracted light intensity D of the pattern of the mask 9 is large. Expression (2) is a more general expression of Expression (1). In this way, the first light emitting region I1 is formed in the region of the pupil plane of the illumination optical system 10 corresponding to the region of the intensity distribution of the diffracted light of the mask pattern with respect to the first wavelength region λ1 that is larger than the reference intensity. Good. From Expression (2), various modified illuminations as shown in FIG. 10 can be obtained as described in the fourth embodiment.

<Example 4>
10(a) to 10(g) are diagrams showing various modified illuminations in the present embodiment obtained from the equation (2). In FIGS. 10A to 10G, the light emitting regions indicated by black, diagonal lines, and horizontal lines have different wavelength ranges. The broadband lighting in this embodiment does not limit the wavelength range. The wavelength range used for the modified illumination may include a wavelength shorter than the i-line or a wavelength longer than the g-line.

FIG. 10A shows a case where the first light emitting region I1 including the light in the first wavelength range λ1 and the second light emitting region I2 including the light in the second wavelength range λ2 are not divided into the inner side and the outer side. ing. The first light emitting region I1 exists on the inner side and the outer side, and the second light emitting region I2 exists so as to be sandwiched by the first light emitting region I1. In FIG. 10B, the wavelength range is divided into three, that is, a first wavelength range λ1, a second wavelength range λ2, and a third wavelength range λ3, and three emission regions corresponding to the respective wavelength ranges, that is, the first emission range. The case where there is a region I1, a second light emitting region I2, and a third light emitting region I3 is shown. The number of divisions of the wavelength region and the light emitting region may be four or more. In addition to this, for example, the second light emitting region I2 may be a non-light emitting portion (not shown). In other words, the non-light emitting area may exist inside the light emitting area. FIG. 10C shows modified illumination mainly used for a hole pattern, and shows a case where the wavelength range of light is changed inside and outside the small σ illumination. For example, by cutting the long wavelength region in the outer second light emitting region I2, it is possible to suppress film loss due to side lobes when a phase shift mask is used. FIG. 10D shows a case where the small σ illumination and the annular illumination are combined. FIG. 10E shows the case where the angular component corresponding to the specific pattern direction is shielded against the annular illumination. There may be a difference in direction as shown in FIG. FIG. 10F shows a case where the first light emitting region I1 and the second light emitting region I2 have a common inner σ and outer σ, and are divided according to the pattern direction. FIG. 10(g) shows a case where the modified illumination including the first light emitting region I1 and the second light emitting region I2 has 180° rotational symmetry (2 times rotational symmetry) instead of 90° rotational symmetry (4 times rotational symmetry). Shows. As shown in FIG. 10(g), the region of the pattern of the mask 9 where the diffracted light intensity is high may not be rotationally symmetrical by 90 degrees. In addition to these, the present embodiment can be applied to polarized illumination.

<Example 5>
With reference to FIGS. 11A and 11B, configurations of the light source 1 and the illumination optical system 10 that can realize the modified illumination described above will be described. FIG. 11A shows a case where the light source 1 is composed of a first light source 1A and a second light source 1B. The first light source 1A and the second light source 1B emit lights having different wavelengths. The light emitted from each of the first light source 1A and the second light source 1B may be light of a single wavelength, light of a narrow wavelength range, or broadband light. Even if a light source that emits light of a single wavelength or light of a narrow wavelength range is used, if a plurality of light sources are used to realize lights of different wavelength ranges, broadband lighting is used. The modified illumination in the present embodiment includes the first light emitting region I1 and the second light emitting region I2, and the first wavelength region λ1 in the first light emitting region I1 and the second wavelength region λ2 in the second light emitting region I2 are different. Such modified illumination can be formed by combining the light emitted from the first light source 1A and the light emitted from the second light source 1B. The first light source 1A and the second light source 1B may form different light emitting regions, and then they may be combined by the illumination optical system 10. Further, the same light emitting region may be formed by the first light source 1A and the second light source 1B, and the wavelength bands in the first light emitting region I1 and the second light emitting region I2 may be changed by a wavelength filter. The first light source 1A and the second light source 1B may be LED light sources. Further, the number of light sources constituting the light source 1 is not limited to two and may be three or more.

FIG. 11B shows a case where the light source 1 is composed of three broadband light sources 1C. The broadband light source IC emits light having a wide wavelength range. The wavelength ranges of the light emitted from the three broadband light sources 1C are the same. In this case, for example, the first wavelength filter 63A, the second wavelength filter 63B, and the third wavelength filter 63C are provided for each of the three broadband light sources 1C to form light emitting regions including different wavelength ranges for each light source. .. Further, as shown in FIG. 11B, the fourth wavelength filter 65 may be provided without using the first wavelength filter 63A, the second wavelength filter 63B, and the third wavelength filter 63C. In this case, after combining the lights from the three broadband light sources 1C, the fourth wavelength filter 65 forms a light emitting region including different wavelength regions. Furthermore, the first wavelength filter 63A, the second wavelength filter 63B, the third wavelength filter 63C, and the fourth wavelength filter 65 may be used together. These wavelength filters may be provided on the rotary turret, or may be provided on a raster type mechanism for shift driving. This facilitates switching between using the wavelength filter and not using the wavelength filter. Although FIG. 11B shows the case where the number of light sources forming the light source 1 is three, the number of light sources is not limited and may be one, for example. The present embodiment does not limit the method regarding division of the wavelength range and formation of the light emitting area.

The wavelength filter only needs to have a small transmittance for a specific wavelength, and does not need to completely set the transmittance for a specific wavelength to zero (shielding). Further, the wavelength band does not have to be completely divided at the boundary of the light emitting region. Further, not only the wavelength selection by the wavelength filter but also the hologram element may be used to suppress the decrease of the light amount (illuminance).

<Second Embodiment>
A case where the modified illumination described above is applied to a maskless exposure apparatus will be described. The maskless exposure apparatus has, instead of the mask 9, a device that forms a pattern to be transferred onto the substrate 12, for example, a digital mirror device (DMD). The DMD is arranged on the object plane of the projection optical system 11 similarly to the mask 9. The DMD includes a plurality of mirror elements (reflection surfaces) arranged two-dimensionally, and by changing the reflection direction of the light emitted from the light source 1 by the mirror elements, a pattern to be transferred to the substrate 12 is formed. To do.

Even in such a maskless exposure apparatus, when the pattern to be transferred to the substrate 12 has a clear pitch P, the area that the light emitting area should include can be obtained from the equation (1). Therefore, the modified illumination described in the first and second embodiments can also be used in the maskless exposure apparatus.

On the other hand, if the pattern to be transferred to the substrate 12 does not have a clear pitch P, the region that the light emitting region should include cannot be obtained from the equation (1). In such a case, it is preferable to set the light emitting region so as to include the illumination angle at which the diffracted light intensity of the pattern to be transferred onto the substrate 12 is large. Specifically, in the first light emitting region I1 including the light in the first wavelength range λ1, the diffracted light intensity Dp of the pattern to be transferred to the substrate 12 with respect to the first wavelength range λ1 shown in the following formula (3) is the reference intensity. It is better to include a larger area than the above. Here, the reference intensity is, for example, an intensity of 0.6 times or more and 0.9 times or less of the maximum value of the diffracted light intensity Dp.

In Expression (3), pattern represents a pattern to be transferred to the substrate 12, and F represents Fourier transform. From the formula (3), various modified illuminations as shown in FIG. 10 can be obtained as described in the fourth embodiment. As described above, the modified illumination described above can be applied to the exposure apparatus regardless of the presence or absence of the mask.

<Third Embodiment>
With reference to FIG. 12, a process (exposure method) of exposing the substrate 12 in the exposure apparatus 100 will be described. In the present embodiment, the exposure apparatus 100 will be described as an example, but it can be applied to a maskless exposure apparatus.

In S121, the light (broadband light) emitted from the light source 1 is divided into a plurality of wavelength bands, in the present embodiment, a first wavelength band λ1 and a second wavelength band λ2. The wavelength range is divided based on the spectral distribution of light emitted from the light source 1 and the equations (1), (2), and (3). However, the present embodiment does not place any limitation on the method of dividing the wavelength range.

In S123, the first diffracted light intensity distribution D1 of the pattern (mask pattern) of the mask 9 is calculated at the wavelengths included in the first wavelength range λ1 divided in S121. Similarly, in S125, the second diffracted light intensity distribution D2 of the pattern of the mask 9 (mask pattern) is calculated at the wavelengths included in the second wavelength range λ2 divided in S121. The wavelength included in the first wavelength range λ1 (second wavelength range λ2) may be a single wavelength representing the first wavelength range λ1 (second wavelength range λ2), or the first wavelength range λ1( It may be a plurality of wavelengths included in the second wavelength range λ2). When obtaining the diffracted light intensity distributions for a plurality of wavelengths, a final weighted sum is obtained for the diffracted light intensity distributions for the respective wavelengths in consideration of the spectral intensity distribution of the light emitted from the light source 1. The diffracted light intensity distribution (D1, D2) is used.

In S127, the first light emitting region I1 is determined from the first diffraction intensity distribution D1. Similarly, in S129, the first light emitting region I2 is determined from the second diffraction intensity distribution D2. The first light emitting region I1 corresponds to the light emitting region of the first wavelength range λ1, and the second light emitting region I2 corresponds to the light emitting region of the second wavelength range λ2. The present embodiment does not place any limitation on the method of determining the light emitting region.

In S131, the illumination optical system 10 generates modified illumination including the first light emitting region I1 corresponding to the first wavelength range λ1 determined in S127 and the second light emitting region I2 corresponding to the second wavelength range λ2, and the modification is performed. The mask 9 is illuminated with illumination.

In S133, the image of the pattern of the mask 9 illuminated in S131 is projected onto the substrate 12 via the projection optical system 11. As a result, the pattern of the mask 9 is transferred to the substrate 12.

<Fourth Embodiment>
The method of manufacturing an article according to the embodiment of the present invention is suitable for manufacturing an article such as a flat panel display, a liquid crystal display element, a semiconductor element, or a MEMS. Such a manufacturing method includes a step of exposing the substrate coated with the photosensitizer using the above-described exposure apparatus 100 and a step of developing the exposed photosensitizer. In addition, a circuit pattern is formed on the substrate by performing an etching process, an ion implantation process, or the like on the substrate using the developed photosensitive agent pattern as a mask. These steps of exposure, development, etching, etc. are repeated to form a circuit pattern composed of a plurality of layers on the substrate. In a later step, dicing (processing) is performed on the substrate on which the circuit pattern is formed, and chip mounting, bonding, and inspection steps are performed. Further, the manufacturing method may include other well-known steps (oxidation, film formation, vapor deposition, doping, planarization, resist stripping, etc.). The method of manufacturing an article according to the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article as compared with the conventional method.

Although the embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist thereof. For example, the present invention can be applied to a projection optical system of a non-magnification system such as an enlargement system or a reduction system, multiple exposure, or an exposure apparatus using an LED light source.

100: Exposure device 9: Mask 10: Illumination optical system 11: Projection optical system 12: Substrate

Claims (19)

An exposure apparatus for exposing a substrate using light in a plurality of wavelength ranges including a first wavelength range and a second wavelength range,
An illumination optical system that illuminates the mask with the light,
A projection optical system for projecting an image of the pattern of the mask onto the substrate,
The illumination optical system includes at least light in the first wavelength range, and a first intensity distribution in which an intensity ratio between the light in the first wavelength range and the light in the second wavelength range is a first intensity ratio, A second intensity distribution that includes light in the second wavelength region and has a second intensity ratio in which the intensity ratio between the light in the first wavelength region and the light in the second wavelength region is different from the first intensity ratio; An exposure apparatus, wherein an intensity distribution including the above is formed on a pupil plane of the illumination optical system so that the intensity distribution has four-fold rotational symmetry. An exposure apparatus for exposing a substrate using light in a plurality of wavelength ranges including a first wavelength range and a second wavelength range,
An illumination optical system that illuminates the mask with the light,
A projection optical system for projecting an image of the pattern of the mask onto the substrate,
The illumination optical system includes at least the light in the first wavelength range, and a first intensity distribution in which an intensity ratio between the light in the first wavelength range and the light in the second wavelength range is a first intensity ratio, A second intensity distribution that includes light in the second wavelength region and has a second intensity ratio in which the intensity ratio between the light in the first wavelength region and the light in the second wavelength region is different from the first intensity ratio; Forming an intensity distribution including on the pupil plane of the illumination optical system,
In the illumination optical system, the first intensity distribution is formed in a region of the pupil plane corresponding to a region of the intensity distribution of the diffracted light of the mask pattern with respect to the light in the first wavelength region that is larger than the reference intensity. An exposure apparatus, which is characterized in that the intensity distribution is formed. An exposure apparatus for exposing a substrate using light in a plurality of wavelength ranges including a first wavelength range and a second wavelength range,
An illumination optical system that illuminates a device that forms a pattern to be transferred to the substrate,
A projection optical system for projecting an image of the pattern formed by the device onto the substrate,
The illumination optical system includes at least light in the first wavelength range, and a first intensity distribution in which an intensity ratio between the light in the first wavelength range and the light in the second wavelength range is a first intensity ratio, A second intensity distribution that includes light in the second wavelength region and has a second intensity ratio in which the intensity ratio between the light in the first wavelength region and the light in the second wavelength region is different from the first intensity ratio; An exposure apparatus, which forms an intensity distribution including the above on a pupil plane of the illumination optical system. Each of the first intensity distribution and the second intensity distribution is a distribution defined by a pupil radius on the pupil plane of the projection optical system,
The exposure apparatus according to any one of claims 1 to 3, wherein the first intensity distribution and the second intensity distribution are distinguished by the pupil radius. The second wavelength range includes a longer wavelength range than the first wavelength range,
The second intensity distribution includes a distribution having a larger pupil radius than the first intensity distribution,
It is the ratio of the intensity of the light in the second wavelength band and the intensity of the light in the first wavelength band in the first intensity distribution (the intensity of the light in the second wavelength band)/(the light in the first wavelength band). Is the ratio of the intensity of the light in the second wavelength band and the intensity of the light in the first wavelength band in the second intensity distribution (the intensity of the light in the second wavelength band)/(the second intensity band). The intensity of light in one wavelength range) is smaller than that of the exposure apparatus according to any one of claims 1 to 4. The second wavelength range includes a longer wavelength range than the first wavelength range,
The second intensity distribution includes a distribution having a larger pupil radius than the first intensity distribution,
It is the ratio of the intensity of the light in the first wavelength range and the intensity of the light in the second wavelength range in the second intensity distribution (the intensity of the light in the first wavelength range)/(the light in the second wavelength range). Is the ratio of the intensity of the light in the first wavelength range and the intensity of the light in the second wavelength range in the first intensity distribution (the intensity of the light in the first wavelength range)/(the first intensity range). 5. The exposure apparatus according to claim 1, wherein the exposure apparatus has a light intensity of less than two wavelengths). The second wavelength range includes a longer wavelength range than the first wavelength range,
The second intensity distribution includes a distribution having a larger pupil radius than the first intensity distribution,
It is the ratio of the intensity of the light in the second wavelength range and the intensity of the light in the first wavelength range in the second intensity distribution (the intensity of the light in the second wavelength range)/(the light in the first wavelength range). Is the ratio of the intensity of the light in the second wavelength band and the intensity of the light in the first wavelength band in the first intensity distribution (the intensity of the light in the second wavelength band)/(the second intensity band). The intensity of light in one wavelength range) is smaller than that of the exposure apparatus according to any one of claims 1 to 4. The first intensity distribution has the first wavelength region of λ1, the pattern pitch of P, and the numerical aperture of the projection optical system of NA.

The exposure apparatus according to any one of claims 1 to 4, wherein the exposure apparatus includes a pupil radius distribution defined by. 9. The exposure apparatus according to claim 1, wherein the plurality of wavelength ranges include wavelengths corresponding to a plurality of bright lines of a mercury lamp. The illumination optical system includes a wavelength filter for transmitting or blocking light in a specific wavelength range of the plurality of wavelength ranges to form the first intensity distribution and the second intensity distribution. The exposure apparatus according to any one of claims 1 to 9. The exposure apparatus according to claim 2, wherein the reference intensity is 0.6 times or more and 0.9 times or less of a maximum value of the intensity distribution of the diffracted light of the pattern of the mask. The illumination optical system forms the intensity distribution including the first intensity distribution and the second intensity distribution on a pupil plane of the illumination optical system so that the intensity distribution has four-fold rotational symmetry. The exposure apparatus according to claim 3, which is characterized in that The exposure apparatus according to claim 3, wherein the exposure apparatus is a maskless exposure apparatus. An exposure apparatus for exposing a substrate using light in a plurality of wavelength ranges including a first wavelength range and a second wavelength range,
An illumination optical system that illuminates the mask with the light,
A projection optical system for projecting an image of the pattern of the mask onto the substrate,
The illumination optical system includes at least light in the first wavelength range, and a first intensity of an annular shape in which an intensity ratio between the light in the first wavelength range and the light in the second wavelength range is a first intensity ratio. An annular zone including a distribution and at least a light in the second wavelength range, and an intensity ratio between the light in the first wavelength range and the light in the second wavelength range is a second intensity ratio different from the first intensity ratio. A second zone-shaped intensity distribution and a ring-shaped intensity distribution including a second intensity distribution on the pupil plane of the illumination optical system,
The exposure apparatus, wherein the first intensity distribution and the second intensity distribution have different diameters on a pupil plane of the illumination optical system. Each of the first intensity distribution and the second intensity distribution is a distribution defined by a pupil radius on the pupil plane of the projection optical system,
The first intensity distribution includes light having a wavelength of 335 nm or more and 395 nm or less, and is defined by a pupil radius of 0.45 to 0.90,
The exposure apparatus according to claim 14, wherein the second intensity distribution includes light having a wavelength of 395 nm or more and 475 nm or less and is defined by a pupil radius of 0.70 to 0.90. Each of the first intensity distribution and the second intensity distribution is a distribution defined by a pupil radius on the pupil plane of the projection optical system,
The first intensity distribution includes light having a wavelength of 335 nm or more and 395 nm or less and is defined by a pupil radius of 0.45 to 0.70,
15. The exposure apparatus according to claim 14, wherein the second intensity distribution includes light having a wavelength of 335 nm or more and 475 nm or less and is defined by a pupil radius of 0.45 to 0.90. Each of the first intensity distribution and the second intensity distribution is a distribution defined by a pupil radius on the pupil plane of the projection optical system,
The first intensity distribution includes light having a wavelength of 335 nm or more and 420 nm or less and is defined by a pupil radius of 0.45 to 0.70,
The exposure apparatus according to claim 14, wherein the second intensity distribution includes light having a wavelength of 395 nm or more and 475 nm or less and is defined by a pupil radius of 0.70 to 0.90. An exposure method for exposing a substrate using light in a plurality of wavelength ranges including a first wavelength range and a second wavelength range,
Illuminating the mask with the light through an illumination optics;
Projecting an image of the pattern of the mask onto the substrate through a projection optical system,
In the step of illuminating the mask, a first intensity distribution that includes at least light in the first wavelength range and has an intensity ratio of the light in the first wavelength range and the light in the second wavelength range being a first intensity ratio. A second intensity distribution that includes at least light in the second wavelength region and has a second intensity ratio in which the intensity ratio between the light in the first wavelength region and the light in the second wavelength region is different from the first intensity ratio. And an intensity distribution including the following are formed on the pupil plane of the illumination optical system so that the intensity distribution has four-fold rotational symmetry. Exposing a substrate using the exposure apparatus according to any one of claims 1 to 17,
Developing the exposed substrate,
Manufacturing an article from the developed substrate,
A method for manufacturing an article, comprising:

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