JP7457849B2 - Exposure equipment, exposure method, and article manufacturing method - Google Patents

Description

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

A projection exposure device is a device that transfers a pattern formed on a mask (original plate) onto a substrate (plate).It illuminates the mask through an illumination optical system, and images the pattern on the mask through a projection optical system. Project onto the substrate. The illumination optical system illuminates the optical integrator with light from the light source, and generates a secondary light source at an exit surface of the optical integrator corresponding to a 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. Furthermore, the light emitting area forming the secondary light source corresponds to the angular distribution of light illuminating each point on the mask. Note that there is also a maskless exposure apparatus that does not require a mask.

In exposure apparatuses, super-resolution technology (RET) exists as a technology for improving transfer performance for fine patterns. Modified illumination, which optimizes the angular distribution of light that illuminates each point on a mask, is known as one type of RET.

Patent Document 1 discloses that, as modified illumination, the focal position in the first exposure process using the light emitting area of the inner concentric circle part is set to a different position from the focal position in the second exposure process using the light emitting area of the outer concentric circle part. A technique has been proposed. Patent Document 2 describes that in order to reduce line width differences between patterns in a plurality of directions (line width non-uniformity due to pattern direction differences), image contrast contributes to imaging of patterns in directions with relatively low image contrast. A technique has been proposed for shifting the wavelength of a light-emitting region existing in the direction to the shorter wavelength side.

Japanese Patent Application Publication No. 2000-252199 Japanese Patent Application Publication No. 2018-54992

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 coexist by using modified illumination, which is one type of RET. However, the technique disclosed in Patent Document 1 does not take into consideration performing modified illumination that is suitable for each of a plurality of wavelength ranges included in broadband illumination light (broadband illumination light). Therefore, when broadband illumination light is used, the effect of sufficiently improving the transfer performance for fine patterns cannot be obtained.

The technology disclosed in Patent Document 2 uses broadband illumination light, but it is a technology that solves line width non-uniformity due to a pattern direction difference, and is a technology that improves transfer performance for fine patterns, that is, RET. isn't it. In order to obtain the effect of improving transfer performance for fine patterns, it is essential to have a difference in direction of the light emitting region corresponding to a difference in direction of the pattern. The technology disclosed in Patent Document 2 is a different technology that has a different problem to be solved than the present invention, which proposes one type of RET.

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

In order to achieve the above object, an exposure apparatus as one aspect of the present invention includes: an illumination optical system that transforms and illuminates a mask with light from a light source; a projection optical system that projects an image of a pattern of the mask onto a substrate; A wavelength filter is provided on the pupil plane of the illumination optical system to form a first intensity distribution of the annular zone and a second intensity distribution of the annular zone formed outside the first intensity distribution, The wavelength filter is characterized in that the longest wavelength in the wavelength range of light forming the second intensity distribution is longer than the longest wavelength in the wavelength range of light forming the first intensity distribution.

Further objects or other aspects of the present invention will become apparent from the embodiments described below with reference to the accompanying drawings.

The present invention can provide an exposure apparatus that is advantageous for improving the transfer performance of transferring a pattern onto a substrate, for example.

1 is a schematic diagram showing the configuration of an exposure apparatus as one aspect of the present invention. FIG. 3 is a diagram for explaining the configuration of an illumination optical system. FIG. 1 is a diagram for explaining conventional modified illumination. FIG. 2 is a diagram for explaining conventional modified illumination. 5A to 5C are diagrams for explaining modified illumination in the first embodiment. 5A to 5C are diagrams for explaining modified illumination in the first embodiment. It is a figure for explaining modified illumination in a 1st embodiment. FIG. 3 is a diagram for explaining the effect of improving the transfer performance for fine patterns by the modified illumination of the first embodiment. It is a figure for explaining modified illumination in a 1st embodiment. It is a figure for explaining modified illumination in a 1st embodiment. FIG. 2 is a diagram for explaining the configuration of a light source and an illumination optical system. 3 is a flowchart for explaining an exposure method.

A preferred embodiment of the present invention will now be described with reference to the accompanying drawings. Note that in each drawing, the same reference numbers are used for the same components, and duplicated descriptions will be omitted.

FIG. 1 is a schematic diagram showing the configuration of an exposure apparatus 100 as one aspect of the present invention. The exposure apparatus 100 is a lithography apparatus that exposes a substrate using light including a plurality of wavelength ranges to transfer a pattern onto the substrate. The exposure apparatus 100 is used for manufacturing flat panel displays, liquid crystal display elements, semiconductor elements, MEMS, etc., and is particularly suitable as a flat panel display exposure apparatus. The exposure apparatus 100 includes an illumination optical system 10 that illuminates a mask (original) 9, which is a surface to be illuminated, with light from a light source, and arranges 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 a substrate 12 and a stage 38.

In this embodiment, the projection optical system 11 is a reflective optical system that includes mirrors 32, 34, and 36, and reflects light in the order of mirrors 32, 34, 36, 34, and 32, and projects an image of the pattern of the mask 9 onto the substrate 12 at life-size. The projection optical system 11 is a reflective optical system in which the chromatic aberration of light from the light source is smaller than that of a refractive optical system, and is therefore suitable for use when using broadband light (broadband illumination light) that includes multiple wavelength ranges. The stage 38 is a stage that can hold the substrate 12 and move.

<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. The illumination optical system 10 includes a condenser mirror 2, a condenser lens 5, a fly's eye lens 7, a condenser lens 8, and an aperture stop 61, as shown in FIG. Note that an optical system (not shown) is arranged on the optical path from the condenser lens 5 to the mask 9 to shape the light from the light source 1 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 light of a plurality of wavelengths is mixed). In this embodiment, the light source 1 includes a mercury lamp that emits ultraviolet light, and emits light that includes a mixture of bright lines with multiple peak wavelengths (i-line (365 nm), g-line (405 nm), and h-line (436 nm)). do. The light source 1 includes a light emitting section near a first focal point 3 of a condensing mirror 2, and the condensing mirror 2 condenses the light emitted from the light source 1 onto a second focal point 4.

The condenser lens 5 shapes the light focused on the first focal point 4 into parallel light. The light shaped by the condenser lens 5 enters the entrance surface 7a of the fly's eye lens 7. The fly's eye lens 7 is an optical integrator composed of a plurality of optical elements, specifically, a plurality of minute lenses. The fly's eye lens 7 forms a secondary light source on an exit surface 7b (light exit surface) from light incident on an entrance surface 7a (light entrance surface). The light emitted from the fly's eye lens 7 passes through a plurality of condenser lenses 8 and illuminates the mask 9 in a superimposed manner.

A measuring section (not shown) is arranged on the stage 38. The measurement 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's eye lens 7, such as a CCD sensor.

Modified illumination (oblique incidence illumination) such as annular illumination (distribution of annular shape) and quadrupole illumination, which is one of the super-resolution techniques (RET), is effective for improving resolution. Modified illumination having a predetermined light emitting area (intensity distribution) can be realized by an aperture stop 61 disposed on the exit surface 7b of the fly's eye lens 7 (optical integrator), which corresponds to the pupil plane of the illumination optical system 10.

Here, the pitch of the pattern of the mask 9 (the period of pattern repetition) is P, the wavelength of the light illuminating the mask 9 (the exposure wavelength) is λ, and the numerical aperture of the projection optical system 11 is NA. In this case, the decrease in image contrast due to defocus can be suppressed by illuminating the mask 9 with modified illumination that includes a light-emitting area I that includes an illumination angle σ _c defined by the following formula (1):

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

In 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 with a wide spectrum of light emitted from a light source. However, in the conventional technology, even in flat panel display exposure equipment, the light emitting area of the modified illumination is divided into a single wavelength λ (for example, the wavelength with the highest intensity or the center of gravity with weighted intensity), as in semiconductor exposure equipment. wavelength).

In this embodiment, for the different first wavelength range λ1 and second wavelength range λ2 included in the broadband lighting, different first light emitting regions I1 and second light emitting regions I2 suitable for each wavelength range are used, thereby achieving fine light emission. Improves the transfer performance of patterns. In other words, this embodiment differs from the conventional art in that light in the first wavelength range λ1 and second wavelength range λ2, which are different from each other, is used as illumination light for each of the first light emitting region I1 and the second light emitting region I2. It is different from technology.

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

In this embodiment, in order to improve the resolution by shortening the wavelength, as in the past, the long wavelength light is not completely blocked, but the long wavelength is used in a specific light emitting region, so the depth of focus (DOF) is improved. is maintained. Furthermore, in this embodiment, since long wavelength light is not completely blocked, a decrease in illuminance (a decrease in productivity) can be suppressed.

<Example 1>
A conventional modified illumination will be described as a comparative example with reference to FIGS. 3 and 4. FIG. 3 shows a graph plotting the illumination angle σ _c shown in equation (1). In FIG. 3, a light emitting region I0 indicated by a horizontal line indicates conventional modified illumination, specifically, annular illumination with an inner σ of 0.45 and an outer σ of 0.90. The exposure wavelength is from 335 nm to 475 nm, as indicated by the wavelength range λ0, and is broadband illumination corresponding to the i-line, g-line, and h-line spectra of a mercury lamp. The light emitting region I0 includes the illumination angle σ _c in the wavelength range 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 using pupil coordinates of the illumination optical system. As shown in FIG. 4, the conventional modified illumination is 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 plotting the illumination angle σ _c shown in equation (1). Different first light emitting regions I1 and second light emitting regions I2 are used for mutually different first wavelength ranges λ1 and second wavelength ranges λ2 included in the broadband illumination. Note that 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 to 395 nm, which corresponds to the spectrum of the i-line of the mercury lamp that is the light source 1. The first light-emitting region I1, which includes the light in the first wavelength range λ1, is an annular illumination (distribution of annular shape) with an inner σ of 0.45 and an outer σ of 0.90. Thus, the first light-emitting region I1 includes at least the light in the first wavelength range λ1, and is a first intensity distribution in which the intensity ratio between the light in the first wavelength range λ1 and the light in the second wavelength range λ2 is a first intensity ratio. The first light-emitting region I1 includes an illumination angle σ _c of the first wavelength range λ1, and such modified illumination has the effect of suppressing the decrease in image contrast caused by defocus, as described above.

The second wavelength range λ2 is a wavelength range of 395 nm or more and 475 nm or less, and is a wavelength range that corresponds to the spectra of the g-line and h-line of the mercury lamp that is the light source 1. The second light emitting region I2 containing light in the second wavelength range λ2 is annular illumination (distribution in an annular shape) with an inner σ of 0.70 and an outer σ of 0.90. In this way, the second light emitting region I2 includes at least light in the second wavelength range λ2, and the second light emitting region I2 includes a light emitting region in which the intensity ratio of the light in the first wavelength range λ1 and the light in the second wavelength range λ2 is different from the first intensity ratio. This is a second intensity distribution having a two-intensity ratio. The second light emitting region I2 includes an illumination angle σ _c for a part of the second wavelength range λ2, and as described above, such modified illumination has the effect of suppressing a decrease in image contrast due to defocusing. .

In this way, the modified illumination of this 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 in the pupil plane of the illumination optical system 10. Different sizes. In addition, the modified illumination of this embodiment is annular illumination in the wavelength range corresponding to the i-line, g-line, and h-line with an inner σ of 0.45 and an outer σ of 0.80. The wavelength range corresponding to the g-line and h-line with 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. It is preferable that the non-light-emitting region D is a region different from the illumination angle σ _c . However, the non-light-emitting region D does not have to include the illumination angle σ _c , and may include the illumination angle σ _c at some wavelengths within the wavelength range. The wavelength range in the non-light emitting region D can be cut by providing a wavelength filter in the illumination optical system 10. For example, as shown in FIG. 2, a wavelength file 63 that transmits or blocks light in a specific wavelength range among a plurality of wavelength ranges to form a first light emitting region I1 and a second light emitting region I2 is attached to the illumination optical system 10. It may be placed near the pupil plane.

The modified illumination of this embodiment shown in FIG. 5 can also be expressed as modified illumination shown in FIG. 6. The modified illumination shown in FIG. 6 will be described. The first wavelength range λ1 is a wavelength range of 335 nm to 395 nm, which corresponds to the spectrum of the i-line of the mercury lamp, which is the light source 1. The first light-emitting region I1, which includes the light of the first wavelength range λ1, is an annular illumination with 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 to 475 nm, which corresponds to the spectrum of the i-line, g-line, and h-line of the mercury lamp, which is the light source 1. The second light-emitting region I2, which includes the light of the second wavelength range λ2, is an annular illumination with an inner σ of 0.70 and an outer σ of 0.90. In this way, the division of the multiple wavelength ranges may include wavelengths included in both the first wavelength range λ1 and the second wavelength range λ2 within the wavelength range. In other words, the first wavelength range λ1 and the second wavelength range λ2 may have some overlapping wavelength ranges.

FIG. 7 is a diagram showing the modified illumination of this embodiment shown in FIGS. 5 and 6 using pupil coordinates of the illumination optical system. Referring to FIG. 7, the wavelength range inside the shaded ring zone (inner σ is 0.45, outer σ is 0.70) is from 335 nm to 395 nm, which corresponds to i-line, g-line and The h line is cut. The wavelength range outside the ring zone shown in black (inner σ is 0.45, outer σ is 0.90) is from 335 nm to 475 nm, and corresponds to i-line, g-line, and h-line. As shown in FIG. 7, in this 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 It is formed on the pupil plane of the illumination optical system 10 so as to be rotationally symmetrical.

With reference to FIG. 8, the effect of improving the transfer performance for fine patterns by the modified illumination of this embodiment will be described. FIG. 8 shows a comparison of transfer performance between the conventional technology (FIG. 3) and Example 1 of the present embodiment (FIG. 7) for a line-and-space (LS) pattern with a line width of 1.5 μm and a pitch (period) of 3 μm. FIG. The numerical aperture (NA) of the projection optical system is 0.10. The LS pattern includes seven lines, with the center line being evaluated. DOF is evaluated by defocusing at which the line width of the center line is -10%.

As shown in FIG. 8, in Example 1 of this embodiment, the image contrast is improved from 0.53 to 0.56, and the DOF of the resist image is improved from 47.5 μm to 70.0 μm, compared to the conventional technology. In Example 1 of this embodiment, the side wall angle of the resist image is improved from 69.4 degrees to 70.9 degrees, compared to the conventional technology. Although not shown in FIG. 8, the MEEF (Mask Error Enhancement Factor) is also improved with the improvement in image contrast. These results show that the transfer performance corresponding to fine patterns can be improved by using light of different wavelength ranges for each light-emitting region, as in this embodiment. In Example 1 of this embodiment, the g-line and h-line are not used inside the annular zone (inner σ is 0.45, outer σ is 0.70), so the illuminance is 74% of the illuminance of the conventional technology.

Specifically, in Example 1 of the present embodiment, the significant improvement in DOF includes the effect of using an annular zone with σ of 0.70 or more. Light in an 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 as it is defocused. Therefore, 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, so that the DOF can be greatly improved. In this way, by using a light emitting region with a large σ, it is possible to improve the DOF of the LS pattern.

<Example 2>
With reference to FIG. 9, modified illumination in Example 2 of this embodiment will be described. FIG. 9 shows a graph plotting the illumination angle σ _c shown in equation (1). As shown in FIG. 9, in the modified illumination of Example 2, in addition to a non-light-emitting region D1 corresponding to σ within the long wavelength range, there is a non-light-emitting region D2 corresponding to σ outside the short wavelength range. The non-light emitting regions D1 and D2 are regions having a different 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 light in the first wavelength range λ1 is annular illumination with an inner σ of 0.45 and an outer σ of 0.70. The second long range λ2 is a wavelength range of 395 nm or more and 475 nm or less. The second light emitting region I2 including light in the second wavelength range λ2 is annular illumination with 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. As shown in the non-emissive 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 expressed by the pupil coordinates of the illumination optical system, similar to FIG. 7. In this case, in FIG. 7, the wavelength range inside the annular zone indicated by diagonal lines (inner σ is 0.45, outer σ is 0.70) is from 335 nm to 420 nm, and outside the annular zone indicated in black (inner σ is 0.70). The wavelength range where σ is 0.45 and outer σ is 0.90 is from 395 nm to 475 nm.

Example 3
When 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 formula (1). In such a case, it is preferable to make the light-emitting area include an illumination angle with a large diffracted light intensity. Specifically, the first light-emitting area I1 including light in the first wavelength range λ1 should include an area where the diffracted light intensity (intensity distribution) D of the mask pattern for the first wavelength range λ1 shown in the following formula (2) is large.

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

When the pattern of the mask 9 has a clear pitch P, formula (1) corresponds to an area where the diffracted light intensity D of the pattern of the mask 9 is large. Formula (2) is a more general expression of formula (1). In this way, the first light-emitting area I1 may be formed in an area on the pupil plane of the illumination optical system 10 that corresponds to an area where the intensity distribution of the diffracted light of the mask pattern for the first wavelength range λ1 is greater than the reference intensity. From formula (2), various modified illuminations such as those shown in FIG. 10 can be obtained, as will be described in Example 4.

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

FIG. 10(a) shows a case where the first light emitting region I1 containing light in the first wavelength range λ1 and the second light emitting region I2 containing light in the second wavelength range λ2 are not divided into inner and outer parts. ing. The first light emitting region I1 exists on the inside and the outside, and the second light emitting region I2 exists sandwiched between the first light emitting region I1. In FIG. 10(b), the wavelength range is divided into three, a first wavelength range λ1, a second wavelength range λ2, and a third wavelength range λ3. A case is shown in which there is a region I1, a second light emitting region I2, and a third light emitting region I3. Note that the number of divisions of the wavelength range 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, a non-light-emitting region may exist inside the light-emitting region. FIG. 10C shows a modified illumination mainly used for hole patterns, in which the wavelength range of light is changed between the inside and outside of the small σ illumination. For example, by cutting off the long wavelength region in the outer second light emitting region I2, film thinning due to side lobes can be suppressed when a phase shift mask is used. FIG. 10(d) shows a case where small σ illumination and annular illumination are combined. FIG. 10E shows a case where an angular component corresponding to a specific pattern direction is blocked for annular illumination. As shown in FIG. 10(e), there may be a difference in direction. FIG. 10(f) 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 is not 90-degree rotationally symmetric (4-fold rotationally symmetric) but 180-degree rotationally symmetric (2-fold rotationally symmetric). It shows. As shown in FIG. 10(g), the region where the intensity of the diffracted light of the pattern of the mask 9 is high may not be rotationally symmetrical by 90 degrees. In addition to these, it is also possible to apply this embodiment to polarized illumination.

<Example 5>
With reference to FIGS. 11(a) and 11(b), the configurations of the light source 1 and the illumination optical system 10 that can realize the above-described modified illumination will be described. FIG. 11(a) 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 light having different wavelengths. Moreover, 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 the light source emits light of a single wavelength or light in a narrow wavelength range, broadband lighting is used when multiple light sources are used to emit light in different wavelength ranges. The modified illumination in this embodiment includes a first light emitting region I1 and a second light emitting region I2, and the first wavelength range λ1 in the first light emitting region I1 is different from the second wavelength range λ2 in the second light emitting region I2. 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. After the first light source 1A and the second light source 1B form mutually different light emitting regions, they may be combined by the illumination optical system 10. Alternatively, the first light source 1A and the second light source 1B may form the same light emitting region, and the wavelength ranges in the first light emitting region I1 and the second light emitting region I2 may be changed using 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. 11(b) shows a case where the light source 1 is composed of three broadband light sources 1C. A broadband light source IC emits light with a wide wavelength range. Note that the wavelength range of the light emitted from the three broadband light sources 1C is the same. In this case, for example, a first wavelength filter 63A, a second wavelength filter 63B, and a third wavelength filter 63C are provided for each of the three broadband light sources 1C to form light emitting regions including mutually different wavelength ranges for each light source. . Further, as shown in FIG. 11(b), a 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 the lights from the three broadband light sources 1C are combined, the fourth wavelength filter 65 forms light emitting regions including mutually different wavelength ranges. Furthermore, the first wavelength filter 63A, the second wavelength filter 63B, and the third wavelength filter 63C may be used together with the fourth wavelength filter 65. These wavelength filters may be provided on a rotating turret, or may be provided on a shift-driven raster type mechanism. This makes it easy to switch between using a wavelength filter and not using a wavelength filter. Although FIG. 11(b) shows a case where the number of light sources configuring the light source 1 is three, the number of light sources is not limited, and may be one, for example. This embodiment does not limit the method for dividing wavelength ranges or forming light emitting regions.

The wavelength filter only needs to reduce the transmittance for a specific wavelength, and there is no need to completely reduce the transmittance to zero (shield light) for a specific wavelength. Further, the wavelength range does not need to be completely divided at the boundary between the light emitting regions. Furthermore, the reduction in the amount of light (illuminance) may be suppressed by using not only wavelength selection using a wavelength filter but also a hologram element.

Second Embodiment
A case where the above-mentioned modified illumination is applied to a maskless exposure apparatus will be described. The maskless exposure apparatus has a device, such as a digital mirror device (DMD), which forms a pattern to be transferred onto a substrate 12, instead of a mask 9. The DMD is disposed on the object plane of a projection optical system 11, similar to the mask 9. The DMD includes a plurality of mirror elements (reflective surfaces) arranged two-dimensionally, and the mirror elements change the reflection direction of light emitted from a light source 1 to form a pattern to be transferred onto the substrate 12.

Even in such a maskless exposure apparatus, if the pattern to be transferred to the substrate 12 has a clear pitch P, the area to be included in the light emitting area can be determined from equation (1). Therefore, the modified illumination described in Example 1 and Example 2 can also be used in a 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 area to be included in the light emitting area cannot be determined from equation (1). In such a case, it is preferable to set the light emitting region so as to include an illumination angle at which the intensity of the diffracted light of the pattern to be transferred to the substrate 12 is large. Specifically, in the first light emitting region I1 including light in the first wavelength range λ1, the diffracted light intensity Dp of the pattern to be transferred to the substrate 12 for the first wavelength range λ1 shown in the following equation (3) is the reference intensity. It is better to include an area larger than . Here, the reference intensity is, for example, an intensity that is 0.6 times or more and 0.9 times or less of the maximum value of the diffracted light intensity Dp.

In equation (3), pattern represents the pattern to be transferred to the substrate 12, and F represents the Fourier transform. From equation (3), various modified illuminations as shown in FIG. 10 can be obtained as described in Example 4. In this way, the above-described modified illumination can be applied to an exposure apparatus regardless of the presence or absence of a mask.

<Third embodiment>
With reference to FIG. 12, a process (exposure method) for exposing the substrate 12 in the exposure apparatus 100 will be described. Although this embodiment will be described using the exposure apparatus 100 as an example, it is also possible to apply the present invention to a maskless exposure apparatus.

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

In S123, the first diffracted light intensity distribution D1 of the pattern of the mask 9 (mask pattern) is calculated using 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 using 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 wavelength included in the first wavelength range λ1 ( It may be a plurality of wavelengths included in the second wavelength range λ2). When calculating the diffracted light intensity distribution for multiple wavelengths, the final value can be calculated by calculating a weighted sum of the diffracted light intensity distribution for each wavelength, taking into account the spectral intensity distribution of the light emitted from the light source 1. Let it be the diffracted light intensity distribution (D1, D2).

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 a light emitting region in the first wavelength range λ1, and the second light emitting region I2 corresponds to a light emitting region in the second wavelength range λ2. This embodiment does not impose any limitations on the method of determining the light emitting area.

In S131, the illumination optical system 10 generates modified illumination including a first light-emitting region I1 corresponding to the first wavelength range λ1 determined in S127 and a second light-emitting region I2 corresponding to the second wavelength range λ2, and the mask 9 is illuminated with the modified 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 onto the substrate 12.

<Fourth embodiment>
The article manufacturing method according to the embodiment of the present invention is suitable for manufacturing articles such as flat panel displays, liquid crystal display elements, semiconductor elements, MEMS, etc., for example. This manufacturing method includes a step of exposing a substrate coated with a photosensitive agent using the exposure apparatus 100 described above, and a step of developing the exposed photosensitive agent. Further, using the developed photosensitive material pattern as a mask, an etching process, an ion implantation process, etc. are performed on the substrate to form a circuit pattern on the substrate. By repeating these steps of exposure, development, etching, etc., a circuit pattern consisting of a plurality of layers is formed on the substrate. In a post-process, the substrate on which the circuit pattern has been formed is subjected to dicing (processing), and chip mounting, bonding, and inspection steps are performed. Such manufacturing methods may also include other well-known steps (oxidation, deposition, vapor deposition, doping, planarization, resist stripping, etc.). The method for 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 compared to 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 non-equal magnification projection optical system such as an enlargement system or a reduction system, or an exposure apparatus using multiple exposure or an LED light source.

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

Claims (8)

an illumination optical system that transforms and illuminates the mask with light from a light source;
a projection optical system that projects an image of the pattern of the mask onto the substrate;
A wavelength filter that forms a first intensity distribution of an annular zone and a second intensity distribution of an annular zone formed outside the first intensity distribution is provided on a pupil plane of the illumination optical system,
The wavelength filter is characterized in that the longest wavelength in the wavelength range of light forming the second intensity distribution is longer than the longest wavelength in the wavelength range of light forming the first intensity distribution. Exposure equipment. 2. The exposure apparatus according to claim 1, wherein the wavelength filter is arranged so that a shortest wavelength in the wavelength range of light forming the first intensity distribution is shorter than a shortest wavelength in the wavelength range of light forming the second intensity distribution. At least a portion of the first intensity distribution has a wavelength range of light forming the first intensity distribution of λ1, a pitch of the pattern of P, a numerical aperture of the projection optical system of NA , and pupil coordinates of the pupil plane. Let σ be the distance from the origin ,
σ= λ1/(2NA・P)
3. The exposure apparatus according to claim 1 , wherein the exposure apparatus satisfies the following . At least a portion of the second intensity distribution has a wavelength range of light forming the second intensity distribution of λ2, a pitch of the pattern P, a numerical aperture of the projection optical system NA , and pupil coordinates of the pupil plane. Let σ be the distance from the origin ,
σ= λ2/(2NA・P)
The exposure apparatus according to claim 1 or 2 , wherein the exposure apparatus satisfies the following . The wavelength range of the light forming the first intensity distribution and the wavelength range of the light forming the second intensity distribution include wavelengths corresponding to a plurality of bright lines of a mercury lamp . The exposure apparatus according to any one of these. The first intensity distribution includes light with a wavelength of 335 nm or more and 395 nm or less,
6. The exposure apparatus according to claim 1 , wherein the second intensity distribution includes light having a wavelength of 395 nm or more and 475 nm or less. An exposure method that exposes a substrate using light from a light source,
deforming and illuminating the mask with the light via an illumination optical system;
projecting an image of the pattern of the mask onto the substrate via a projection optical system,
In the step of illuminating the mask in a modified manner ,
A wavelength filter is provided on the pupil plane of the illumination optical system, thereby forming a first intensity distribution of an annular zone and a second intensity distribution of an annular zone outside the first intensity distribution on the pupil plane,
The longest wavelength in the wavelength range of the light forming the second intensity distribution is longer than the longest wavelength in the wavelength range of the light forming the first intensity distribution.
An exposure method characterized by: A step of exposing a substrate using the exposure apparatus according to any one of claims 1 to 6 ;
Developing the exposed substrate;
manufacturing an article from the developed substrate;
A method for manufacturing an article characterized by having the following.

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