Photoetching system based on 1: 1 positive image projection imaging, photoetching method and positive image projection system

Abstract

The invention discloses a photoetching system based on 1: 1 positive image projection imaging, a photoetching method and a positive image projection system. The photoetching system comprises a scanning workbench, a plane driving mechanism, a mask workbench used for placing a mask, a substrate workbench used for placing a substrate and an optical system, and the relative position of the mask workbench and the substrate workbench is kept unchanged; the plane driving mechanism is configured to drive the frame assembly to do plane motion on the scanning workbench; the optical system comprises an illumination assembly and a projection assembly. The projection assembly comprises a first refraction and reflection type lens group and a second refraction and reflection type lens group which are connected in series and have the same lens arrangement structure. Light emitted by the lighting assembly sequentially passes through the mask workbench, the first catadioptric lens group and the second catadioptric lens group and then reaches the substrate workbench, and 1: 1 positive image projection is formed on the substrate workbench. The method is suitable for a spectrum i line / h line / g line, and has a good apochromatic effect.

Description

Technical Field

[0001] The present invention relates to the field of photolithography, and in particular to a photolithography system, a photolithography method and a positive image projection system based on 1:1 positive image projection imaging. Background Art

[0002] At present, projection lithography technology has been widely used in the manufacture of integrated circuits (ICs) with nanometer resolution. At the same time, in the field of semiconductor back-end processes, such as silicon wafer-level chip scale packaging and bump packaging processes, projection lithography technology has also become a mainstream technology, and the introduction of larger silicon wafers in the future will better reflect the advantages of projection lithography technology. The optical system of projection lithography technology used in packaging processes needs to have micron-level lithography resolution capabilities and has high yield and low-cost technical characteristics.

[0003] Current lithography systems usually use a dual scanning stage structure in which the mask and substrate perform opposite movements for scanning. Projection lenses that meet the above conditions generally have complex structures, narrow applicable spectral ranges, poor thermal stability, and cannot control and adjust the shape of the photosensitive resin after curing. It is difficult to meet the large exposure dose requirements in the lithography process.

[0004] The disclosure of the above background technology content is only used to assist in understanding the concept and technical solution of the present application. It does not necessarily belong to the prior art of the present application, nor does it necessarily provide technical guidance. In the absence of clear evidence that the above content has been disclosed before the filing date of the present application, the above background technology should not be used to evaluate the novelty and creativity of the present application. Summary of the invention

[0005] The purpose of the present invention is to provide a lithography system that only requires one scanning workbench, keeps the relative positions of the mask and the substrate unchanged, improves the projection component to achieve 1:1 positive image projection, and is suitable for spectral i-line / h-line / g-line.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A lithography system based on 1:1 positive projection imaging, comprising a scanning table, a plane driving mechanism, a frame assembly, and an optical system, wherein the frame assembly comprises a frame body, a mask table arranged on the upper part of the frame body, and a substrate table arranged on the lower part of the frame body, wherein the mask table is configured to place a mask having an exposure pattern and a first alignment mark, and the substrate table is configured to place a substrate having a photosensitive material and a second alignment mark, and the relative positions of the mask table and the substrate table remain unchanged;

[0008] The planar driving mechanism is configured to drive the frame assembly to perform planar motion on the scanning table;

[0009] The optical system comprises an illumination assembly and a projection assembly, wherein the projection assembly comprises two groups of first and second catadioptric mirror groups connected in series, wherein the first and second catadioptric mirror groups have the same lens arrangement structure;

[0010] The light emitted by the lighting assembly passes through the mask workbench, the first folding reflective mirror group, and the second folding reflective mirror group in sequence and then reaches the substrate workbench, and forms a 1:1 erect image projection on the substrate workbench. The first alignment mark and the second alignment mark are used to characterize the alignment of the mask and the substrate.

[0011] Further, based on any one of the above-mentioned technical solutions or a combination of multiple technical solutions, the first catadioptric mirror group and the second catadioptric mirror group both have the following lens arrangement structure, including:

[0012] A first reflecting surface, a first lens group, a second lens group, a third lens group, a reflecting mirror and a second reflecting surface, wherein the first lens group and the second lens group both have positive optical power, and the third lens group includes at least one negative lens with negative optical power;

[0013] The light from the object surface is reflected by the first reflecting surface and then passes through the first mirror group, the second mirror group, and the third mirror group in sequence to reach the reflecting mirror. The light reflected by the reflecting mirror passes through the third mirror group, the second mirror group, and the first mirror group in reverse order to reach the second reflecting surface, and then reaches the image surface after being reflected by the second reflecting surface.

[0014] Further, based on any one of the above technical solutions or a combination of multiple technical solutions, the object plane of the first catadioptric mirror group is located at the position of the mask on the mask workbench, and the image plane of the first catadioptric mirror group coincides with the object plane of the second catadioptric mirror group;

[0015] The image plane of the second catadioptric mirror assembly is located at the position of the substrate at the substrate workbench;

[0016] The first catadioptric mirror set and the second catadioptric mirror set form a projection assembly for 1:1 erect image projection.

[0017] Further, based on any one of the above-described technical solutions or a combination of multiple technical solutions, both the first catadioptric lens group and the second catadioptric lens group satisfy: 0.45 < F1 / L < 1.5. If this ratio exceeds the upper limit, excessive primary spherical aberration and high-order spherical aberration will be caused. If this ratio is lower than the lower limit, excessive astigmatism aberration will be caused, affecting the optical performance of the lens; 0.45 < F2 / L < 1.05. If this ratio exceeds the upper limit, excessive spherical aberration and axial chromatic aberration will be caused. If this ratio is lower than the lower limit, excessive astigmatism aberration will be caused, affecting the optical performance of the lens. Herein, F1 is the combined focal length of the first lens group, F2 is the combined focal length of the second lens group, and L is the optical distance from the object plane to the reflecting surface of the reflector;

[0018] And / or, the reflectors of the first catadioptric lens group and the second catadioptric lens group both have concave reflecting surfaces, and the curvature radius R of the concave reflecting surface and the optical distance L from the object plane to the concave reflecting surface satisfy the following expression: 0.7 < -R / L < 1.5;

[0019] And / or, the third lens group sequentially includes a positive-power lens, a biconcave lens, and a positive-power lens with a convex object side surface. The focal length f3 of the biconcave lens and the optical distance L from the object plane to the reflecting surface of the reflector satisfy the following expression: 0.15 < |f3| / L < 0.7; if this ratio exceeds the upper limit, excessive spherical aberration and high-order axial chromatic aberration will be caused. If this ratio is lower than the lower limit, insufficient compensation for high-order axial chromatic aberration will be caused. In both cases, a good apochromatic effect cannot be achieved, affecting the optical performance of the lens;

[0020] And / or, the lens closest to the first lens group in the second lens group is a positive-power lens, and the curvature radius r21 of the object side surface of the positive-power lens and the curvature radius r22 of its image side surface satisfy the following expression: 0 < |r21 / r22| < 0.5; satisfying this relationship can simultaneously achieve good compensation for spherical aberration and astigmatism aberration, improving the optical performance of the lens group;

[0021] And / or, the lens closest to the object plane in the first lens group is a biconvex lens, and the dispersion coefficient of the biconvex lens is defined as Vd1; the lens closest to the first lens group in the second lens group is a positive-power lens, and the dispersion coefficient of the positive-power lens is defined as Vd2; the third lens group includes multiple lenses, and the minimum dispersion coefficient of the negative lenses is defined as Vd3, and the following relationships are satisfied: 20 < Vd1 - Vd2 < 55, 18 < Vd1 - Vd3 < 53; satisfying these two relationships can achieve balanced compensation for spherical aberration and axial chromatic aberration, achieving an apochromatic effect and improving the optical performance of the lens in a wide spectral range;

[0022] And / or, both the first catadioptric lens group and the second catadioptric lens group satisfy: 0.05 < Hy / F1 < 0.35, where Hy is the image height corresponding to the maximum field of view angle of the catadioptric lens group, and F1 is the combined focal length of the first lens group. If this ratio exceeds the upper limit, the astigmatic aberration is too large; if this ratio is lower than the lower limit, the lens length becomes longer, resulting in a bulky device and affecting the overall performance of the device.

[0023] Further, based on any one of the foregoing technical solutions or a combination of multiple technical solutions, the first lens group, the second lens group, the third lens group, and the reflector are arranged along the optical axis. The first reflecting surface and the second reflecting surface are two surfaces on the same reflector, and the first reflecting surface and the second reflecting surface are symmetrically distributed about the optical axis; both the first reflecting surface and the second reflecting surface are planes, and / or both the first reflecting surface and the second reflecting surface form an angle of 135° with the optical axis;

[0024] The first lens group includes a first lens, the image-side optical axis position of which is convex and has a positive optical power;

[0025] The second lens group includes a second lens, the object-side optical axis position of which is convex, and the image-side optical axis position of which is convex or concave;

[0026] The third lens group includes a third lens, a fourth lens, and a fifth lens. The third lens is a biconvex lens, the fourth lens is a biconcave lens, and the fifth lens is a positive optical power lens with a convex structure at the object-side optical axis position.

[0027] Further, based on any one of the foregoing technical solutions or a combination of multiple technical solutions, the illumination assembly includes a light source, a homogenizing lens, and a condenser lens. The homogenizing lens uses a fly-eye integrator or a square rod integrator to homogenize the light beam emitted by the light source. The condenser lens focuses and transmits the homogenized light beam onto the mask located at the mask stage. The exit pupil position of the light beam emitted by the condenser lens coincides with the entrance pupil position of the projection assembly.

[0028] Further, based on any one of the foregoing technical solutions or a combination of multiple technical solutions, the light source is a high-pressure mercury lamp or an LED lamp having one or more wavelengths, and the light beam emitted by it includes characteristic spectral lines of 365 nm, 405 nm, and 436 nm;

[0029] The illumination assembly and the projection assembly remain stationary relative to the scanning stage;

[0030] The exposure area output by the illumination assembly has a sharp corner structure in the vertical scanning direction.

[0031] Further, based on any one of the above technical solutions or a combination of multiple technical solutions, the optical system further includes an alignment position fine-tuning mechanism, which is installed between the mask workbench and the first catadioptric mirror group, or between the first catadioptric mirror group and the second catadioptric mirror group, or between the second catadioptric mirror group and the substrate workbench;

[0032] The alignment position fine-tuning mechanism includes an optically transparent plate and an adjusting device, wherein the adjusting device is configured to adjust the angle of the optically transparent plate relative to the scanning workbench so that the projection of the first alignment mark on the substrate coincides with the second alignment mark.

[0033] According to another aspect of the present invention, the present invention provides a lithography method based on the lithography system as described above, comprising the following steps:

[0034] Placing a substrate to be photolithographically processed on a substrate workbench, and placing a corresponding mask on the mask workbench;

[0035] Using the adjustment device of the alignment position fine adjustment mechanism to adjust the angle of the optical transparent flat plate relative to the scanning table of the photolithography system until the projection of the first alignment mark on the mask on the substrate coincides with the second alignment mark on the substrate;

[0036] The light source of the photolithography system is controlled to emit i-line, h-line and / or g-line spectra, and a frame assembly of the photolithography system is driven to move along a scanning path on a scanning table through a planar driving mechanism, wherein the scanning path is related to an exposure pattern on the mask.

[0037] According to another aspect of the present invention, the present invention provides a 1:1 erect image projection system, comprising two groups of first catadioptric mirror groups and second catadioptric mirror groups connected in series, wherein the first catadioptric mirror group and the second catadioptric mirror group have the same lens arrangement structure, comprising:

[0038] A first reflecting surface, a first lens group, a second lens group, a third lens group, a reflecting mirror, and a second reflecting surface, wherein the first lens group and the second lens group both have positive optical power, and the third lens group includes at least one negative lens;

[0039] The light from the object plane is reflected by the first reflection surface and then passes through the first mirror group, the second mirror group, and the third mirror group in sequence before reaching the reflection mirror. The light reflected by the reflection mirror passes through the third mirror group, the second mirror group, and the first mirror group in reverse order before reaching the second reflection surface, and then reaches the image plane after being reflected by the second reflection surface.

[0040] Among them, the object plane of the first folding reflector group is located at the position of the optical mask in the lithography system, and the image plane of the first folding reflector group coincides with the object plane of the second folding reflector group; the image plane of the second folding reflector group is located at the position of the substrate to be projected in the lithography system; the first folding reflector group and the second folding reflector group form a 1:1 erect image projection.

[0041] The beneficial effects brought by the technical solution provided by the present invention are as follows:

[0042] a. Only one scanning table is needed to perform scanning exposure while keeping the relative positions of the mask and substrate unchanged. The magnification is strictly controlled to be 1. The motion uniformity and serpentine swing error of the scanning table are not required to be high, and the structure is greatly simplified to reduce costs.

[0043] b. Two catadioptric mirrors with a specific structure are connected in series to achieve 1:1 erect image projection, and are suitable for spectral i-line / h-line / g-line, with good apochromatic effect;

[0044] c. There is no need to set up an aberration compensation mechanism or a magnification adjustment mechanism, and it is convenient to align the mask and the substrate, and the operation is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 A schematic structural diagram of a photolithography system provided for an exemplary embodiment of the present invention;

[0047] Figure 2 A diagram showing the lens arrangement structure of a catadioptric lens assembly provided for a first embodiment of the present invention;

[0048] Figure 3 for Figure 2 The axial chromatic aberration result curve of the catadioptric lens group;

[0049] Figure 4 A diagram showing the lens arrangement structure of a catadioptric lens assembly provided for a second embodiment of the present invention;

[0050] Figure 5 for Figure 4 The axial chromatic aberration result curve of the catadioptric lens group;

[0051] Figure 6 A schematic diagram of the shape of a first exposure area provided in an embodiment of the present invention;

[0052] Figure 7 A schematic diagram of the shape of a second exposure area provided by an embodiment of the present invention;

[0053] Figure 8 A schematic diagram of a state in which the alignment position fine-tuning mechanism provided in an embodiment of the present invention fine-tunes the exposure light area;

[0054] Fig. 9 A schematic diagram of a state in which the alignment position fine-tuning mechanism provided in an embodiment of the present invention does not fine-tune the exposure light area;

[0055] Fig.10 A schematic diagram of a cross-sectional view of an opening that contracts downwardly by adjusting the photosensitive adhesive coated on the surface of a substrate by selecting an exposure wavelength provided in an embodiment of the present invention;

[0056] Fig.11 A schematic diagram of a cross section of an opening with a vertically equal width formed by adjusting the photosensitive adhesive coated on the surface of a substrate by selecting an exposure wavelength provided in an embodiment of the present invention;

[0057] Fig.12 A schematic diagram of a cross-sectional opening that expands downwardly is provided in an embodiment of the present invention by adjusting the photosensitive adhesive coated on the surface of the substrate by selecting the exposure wavelength. DETAILED DESCRIPTION

[0058] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0059] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, device, product or equipment that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0060] In one embodiment of the present invention, a lithography system based on 1:1 positive projection imaging is provided. Figure 1 As shown, the photolithography system includes a scanning table 100, a planar driving mechanism, a frame assembly, and an optical system, wherein the frame assembly includes a frame body 210, a mask table 220 disposed on the upper part of the frame body 210, and a substrate table 230 disposed on the lower part of the frame body 210, wherein the mask table 220 is configured to place a mask 222 having an exposure pattern and a first alignment mark, and the substrate table 230 is configured to place a substrate 232 having a photosensitive material and a second alignment mark, and the relative positions of the mask table 220 and the substrate table 230 remain unchanged;

[0061] The planar driving mechanism is configured to drive the frame assembly to perform planar motion on the scanning workbench 100;

[0062] The optical system includes an illumination component and a projection component, wherein the projection component includes two groups of first and second catadioptric mirror groups 310 and 320 connected in series, wherein the first and second catadioptric mirror groups 310 and 320 have the same lens arrangement structure;

[0063] The light emitted by the lighting assembly passes through the mask workbench 220, the first folding reflective mirror group 310, and the second folding reflective mirror group 320 in sequence and then reaches the substrate workbench 230, and forms a 1:1 erect image projection on the substrate workbench 230. The first alignment mark and the second alignment mark are used to indicate the alignment of the mask 222 and the substrate 232.

[0064] The lighting assembly includes a light source 410, a homogenizer 420 and a condenser 430. The homogenizer 420 uses a compound eye integrator or a square rod integrator to homogenize the light beam emitted by the light source 410. The condenser 430 collects the homogenized light beam and transmits it to the mask 222 located at the mask workbench 220. The exit pupil position of the light beam emitted by the condenser 430 coincides with the entrance pupil position of the projection assembly.

[0065] Specifically, the light source 410 is a high-pressure mercury lamp or LED lamp with one or more wavelengths, and the light beam emitted by the light source includes characteristic spectral lines of 365nm, 405nm, and 436nm; in particular, the exposure area output by the lighting component has the following characteristics in the vertical scanning direction: Figure 6 and Figure 7 The lighting assembly and the projection assembly remain stationary relative to the scanning workbench 100, as shown in FIG. Figure 1 As shown, for example, the lighting assembly and the projection assembly can be fixed on the floor frame 300 .

[0066] In an ideal situation, Fig. 9 As shown, the exposure light finally reaches the substrate 232 after passing through the mask 222 , and can directly achieve the overlap of the projection of the first alignment mark on the substrate 232 with the second alignment mark 231 .

[0067] In one embodiment of the present invention, the optical system further includes an alignment position fine-tuning mechanism 600, which is installed between the mask workbench 220 and the first catadioptric mirror assembly 310, or between the first catadioptric mirror assembly 310 and the second catadioptric mirror assembly 320, or between the second catadioptric mirror assembly 320 and the substrate workbench 230;

[0068] The alignment position fine-tuning mechanism 600 includes an optically transparent plate and an adjusting device, wherein the adjusting device is configured to adjust the angle of the optically transparent plate relative to the scanning workbench 100 so that the projection of the first alignment mark on the substrate coincides with the second alignment mark 231. Fig. 9 As shown, if the light is incident vertically on the optical transparent plate, the direction of the light will not be changed. This situation where the optical transparent plate does not need to be adjusted is applicable to the above ideal situation.

[0069] When the optically transparent plate is not adjusted, if there is a deviation between the first alignment mark and the second alignment mark 231, the inclination angle between the optically transparent plate and the horizontal plane needs to be adjusted, such as Figure 8 As shown, when the incident light is not incident vertically on the optically transparent plate, the direction of the light incident on the optically transparent plate will change, and the light emitted therefrom will return to the vertical direction, and the incident light and the outgoing light will be horizontally translated, so as to achieve the purpose of the projection of the first alignment mark on the substrate 232 and the second alignment mark 231 to coincide with each other.

[0070] It should be noted that Figure 8 and Fig. 9 It is only a schematic diagram, which ignores the process of light passing through the first folding reflective mirror group 310 and the second folding reflective mirror group 320 , or shows the light path in an embodiment in which the alignment position fine-tuning mechanism 600 is disposed between the second folding reflective mirror group 320 and the substrate workbench 230 .

[0071] The first catadioptric mirror group 310 and the second catadioptric mirror group 320 both have the same lens arrangement structure, such as Figure 2 and Figure 4 As shown, the catadioptric mirror assembly includes:

[0072] A first reflecting surface R1, a first lens group G1, a second lens group G2, a third lens group G3, a reflecting mirror M1 and a second reflecting surface R2, wherein the first lens group G1 and the second lens group G2 both have positive optical power, and the third lens group G3 includes at least one negative lens with negative optical power;

[0073] The light from the object plane P1 is reflected by the first reflection surface R1 and then passes through the first mirror group G1, the second mirror group G2, and the third mirror group G3 in sequence to reach the reflection mirror M1. The light reflected by the reflection mirror M1 passes through the third mirror group G3, the second mirror group G2, and the first mirror group G1 in reverse order to reach the second reflection surface R2, and then reaches the image plane P2 after being reflected by the second reflection surface R2.

[0074] The first catadioptric mirror group 310 and the second catadioptric mirror group 320 are connected in series and form a 1:1 upright projection, which is reflected in that: the object plane P1 of the first catadioptric mirror group 310 is located at the position of the mask 222 at the mask workbench 220, and the image plane P2 of the first catadioptric mirror group 310 coincides with the object plane P1 of the second catadioptric mirror group 320; the image plane P2 of the second catadioptric mirror group 320 is located at the position of the substrate 232 at the substrate workbench 230, and the first catadioptric mirror group 310 and the second catadioptric mirror group 320 constitute a projection component for 1:1 upright projection.

[0075] Specific as Figure 2 and Figure 4 As shown, the first mirror group G1, the second mirror group G2, the third mirror group G3, and the reflector M1 are arranged along the optical axis, the first reflective surface R1 and the second reflective surface R2 are two surfaces on the same reflector, and the first reflective surface R1 and the second reflective surface R2 are symmetrically distributed with the optical axis as the center axis; the first reflective surface R1 and the second reflective surface R2 are both planes, and / or the first reflective surface R1 and the second reflective surface R2 both form an angle of 135° with the optical axis;

[0076] The first lens group G1 includes a first lens L1, whose image-side optical axis is convex and has positive refractive power;

[0077] The second lens group G2 includes a second lens L2, the object-side optical axis position of which is a convex structure, and the image-side optical axis position of which is a convex or concave structure;

[0078] The third lens group G3 includes a third lens L3, a fourth lens L4 and a fifth lens L5, wherein the third lens L3 is a biconvex lens, the fourth lens L4 is a biconcave lens, and the fifth lens L5 is a positive power lens with a convex structure at the object optical axis position.

[0079] The first catadioptric mirror set 310 and the second catadioptric mirror set 320 both satisfy: 0.45 <F1 / L<1.5,0.45<F2 / L<1.05,0.7<-R / L<1.5,0.15<∣f3∣ / L<0.7,0<∣r21 / r22∣<0.5,20<Vd1-Vd2<55,18<Vd1-Vd3<53,0.05<Hy / F1<0.35;

[0080] Wherein, F1 is the combined focal length of the first lens group G1, F2 is the combined focal length of the second lens group G2, L is the optical distance from the object plane P1 to the reflecting surface of the reflecting mirror M1, R is the curvature radius of the reflecting surface of the reflecting mirror M1 having a concave reflecting surface, f3 is the focal length of the fourth lens L4 in the third lens group G3, r21 is the curvature radius of the object side surface of the second lens L2, r22 is the curvature radius of the image side surface of the second lens L2, Vd1 is the dispersion coefficient of the first lens, Vd2 is the dispersion coefficient of the second lens, Vd3 is the dispersion coefficient of the negative lens in the third lens group G3, i.e., the fourth lens L4, and Hy is the image height corresponding to the maximum field angle of the catadioptric lens group;

[0081] Especially satisfied: 0.75 <F1 / L<1.2,0.55<F2 / L<0.86,0.85<-R / L<1.2,0.20<∣f3∣ / L<0.45,0<∣r21 / r22∣<0.05,30<Vd1-Vd2<50,28<Vd1-Vd3<42,0.09<Hy / F1<0.18。

[0082] First embodiment

[0083] In this embodiment, the lenses of the catadioptric mirror assembly are arranged as follows: Figure 2 As shown, the optical parameters of the lenses and reflectors of each catadioptric mirror assembly are shown in Table 1:

[0084] Table 1 Optical parameters of the catadioptric mirror assembly of the first embodiment

[0085]

[0086]

[0087] d0 is defined as the optical axis distance from the object plane to the object side surface of the first lens L1, and d1 is defined as the optical axis distance from the image side surface of the first lens L1 to the object side surface of the second lens L2. According to Table 1, d0=156.2343mm, d1=381.9864mm.

[0088] In this embodiment, the image height Hy corresponding to the maximum field angle of the catadioptric mirror assembly is 105 mm, and the image-side numerical aperture is 0.1, which is a dimensionless parameter, and its calculation formula is NA=n×sin(θ), wherein n is the refractive index, and θ is the angle between the light and the optical axis. The larger the NA value, the wider the angle of light that the optical system can collect or transmit, and thus can provide higher resolution and clearer images.

[0089] In a specific numerical embodiment, the calculation results of the optical parameter relationship of the catadioptric mirror assembly are shown in Table 2:

[0090] Table 2 Calculation results of the optical parameter relationship of the catadioptric mirror assembly of the first embodiment

[0091] Serial number expression Numeric (1) F1 / L= 0.896 (2) F2 / L= 0.728 (3) -R / L= 1.100 (4) ∣r21 / r22∣ 0.021 (5) |f3| / L= 0.362 (6) Vd1-Vd2 44.87 (7) Vd1-Vd3 38.28 (8) Hy / F1= 0.147 (9) (d0+d1) / L= 0.673 (10) F1 / F2= 1.230

[0092] In this embodiment, the calculation value is obtained by rounding off.

[0093] Figure 3 This is a curve diagram of the axial chromatic aberration results of the catadioptric mirror assembly of the present embodiment. The diagram shows that the maximum defocus distance in the wavelength range from 0.36 to 0.44 microns is less than 4 microns, which is much smaller than the 71nm range of the diffraction-limited focal depth. This indicates that the catadioptric mirror assembly of the present embodiment has good wide spectrum performance and is suitable for three spectra of i / h / g lines. The three characteristic spectra compensate for primary and higher-order axial chromatic aberrations and are apochromatic. The present application overcomes the existing technical difficulties in the industry.

[0094] Second embodiment

[0095] In this embodiment, the lenses of the catadioptric mirror assembly are arranged as follows: Figure 4 As shown, the optical parameters of the lenses and reflectors of each catadioptric mirror assembly are shown in Table 3:

[0096] Table 3 Optical parameters of the catadioptric mirror assembly of the second embodiment

[0097]

[0098]

[0099] d0 is defined as the optical axis distance from the object plane to the object side surface of the first lens L1, and d1 is defined as the optical axis distance from the image side surface of the first lens L1 to the object side surface of the second lens L2. According to Table 1, d0=119.9995mm, d1=406.2561mm.

[0100] In this embodiment, the image height Hy corresponding to the maximum field angle of the catadioptric mirror assembly is 105 mm, and the image-side numerical aperture is 0.75, which is a dimensionless parameter, and its calculation formula is NA=n×sin(θ), wherein n is the refractive index, and θ is the angle between the light and the optical axis. The larger the NA value, the wider the angle of light that the optical system can collect or transmit, and thus can provide higher resolution and clearer images.

[0101] In a specific numerical embodiment, the calculation results of the optical parameter relationship of the catadioptric mirror assembly are shown in Table 4:

[0102] Table 4 Calculation results of the optical parameter relationship of the catadioptric mirror assembly of the second embodiment

[0103] Serial number expression Numeric (1) F1 / L= 0.970 (2) F2 / L= 0.673 (3) -R / L= 1.065 (4) ∣r21 / r22∣ 0.015 (5) |f3| / L= 0.266 (6) Vd1-Vd2 34.08 (7) Vd1-Vd3 31.58 (8) Hy / F1= 0.135 (9) (d0+d1) / L= 0.658 (10) F1 / F2= 1.441

[0104] In this embodiment, the calculation value is obtained by rounding off.

[0105] Figure 5 This is a curve diagram of the axial chromatic aberration results of the catadioptric mirror assembly of the present embodiment. The figure shows that the maximum defocus distance in the wavelength range from 0.36 to 0.44 microns is less than 13 microns, which is much smaller than the 71nm range of the diffraction-limited focal depth. This indicates that the catadioptric mirror assembly of the present embodiment has good wide spectrum performance and is suitable for three spectra of i / h / g lines. The three characteristic spectra compensate for primary and higher-order axial chromatic aberrations and are apochromatic. The present application overcomes the existing technical difficulties in the industry.

[0106] When different wavelengths of the light source are selected for exposure, the photosensitive material on the substrate has different morphological characteristics after exposure and development. The optical lens includes a wavelength selection filter. By selecting different wavelength filters, different characteristic spectral line regions are selected, which are suitable for photosensitive materials with different characteristics, or different photosensitive glue curing sections, upper opening sections, vertical sections, and lower opening sections are constructed. Different exposure wavelengths have different depths of action on the photosensitive glue 234, and the upper and lower widths of the opening can be controlled, that is, the exposure wavelength can be selected to adjust the opening shape, respectively as follows: Figure 10-12 shown.

[0107] In one embodiment of the present invention, a lithography method based on the lithography system as described above is provided, comprising the following steps:

[0108] Placing a substrate to be photolithographically processed on a substrate workbench, and placing a corresponding mask on the mask workbench;

[0109] Using the adjustment device of the alignment position fine adjustment mechanism to adjust the angle of the optical transparent flat plate relative to the scanning table of the photolithography system until the projection of the first alignment mark on the mask on the substrate coincides with the second alignment mark on the substrate;

[0110] The light source of the photolithography system is controlled to emit i-line, h-line and / or g-line spectra, and a frame assembly of the photolithography system is driven to move along a scanning path on a scanning table through a planar driving mechanism, wherein the scanning path is related to an exposure pattern on the mask.

[0111] In one embodiment of the present invention, the present invention provides a 1:1 erect image projection system, comprising two groups of first catadioptric mirror groups and second catadioptric mirror groups connected in series, wherein the first catadioptric mirror group and the second catadioptric mirror group have the same lens arrangement structure, including:

[0112] A first reflecting surface, a first lens group, a second lens group, a third lens group, a reflecting mirror, and a second reflecting surface, wherein the first lens group and the second lens group both have positive optical power, and the third lens group includes at least one negative lens;

[0113] The light from the object plane is reflected by the first reflection surface and then passes through the first mirror group, the second mirror group, and the third mirror group in sequence before reaching the reflection mirror. The light reflected by the reflection mirror passes through the third mirror group, the second mirror group, and the first mirror group in reverse order before reaching the second reflection surface, and then reaches the image plane after being reflected by the second reflection surface.

[0114] Among them, the object plane of the first folding reflector group is located at the position of the optical mask in the lithography system, and the image plane of the first folding reflector group coincides with the object plane of the second folding reflector group; the image plane of the second folding reflector group is located at the position of the substrate to be projected in the lithography system; the first folding reflector group and the second folding reflector group form a 1:1 erect image projection.

[0115] The 1:1 erect image projection system provided in this embodiment belongs to the same inventive concept as the above-mentioned lithography system based on 1:1 erect image projection imaging. The entire contents of the lithography system embodiment based on 1:1 erect image projection imaging are incorporated into the present erect image projection system embodiment by citing the full text, and no further details are given.

[0116] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0117] The above is only a specific implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A lithography system based on 1:1 positive projection imaging, characterized in that: It includes a scanning workbench, a planar drive mechanism, a frame assembly, and an optical system. Among them, the frame assembly includes a frame body, a mask workbench arranged on the upper part of the frame body, and a substrate workbench arranged on the lower part of the frame body. The mask workbench is configured to place a mask with an exposure pattern and a first alignment mark, and the substrate workbench is configured to place a substrate with a photosensitive material and a second alignment mark, and the relative positions of the mask workbench and the substrate workbench remain unchanged; The planar drive mechanism is configured to drive the frame assembly to perform planar motion on the scanning workbench; The optical system includes an illumination component and a projection component. The projection component includes two sets of serially connected first catadioptric lens groups and second catadioptric lens groups, and the first catadioptric lens group and the second catadioptric lens group have the same lens arrangement structure; The light emitted by the illumination component passes through the mask workbench, the first catadioptric lens group, and the second catadioptric lens group in sequence and then reaches the substrate workbench, and a 1:1 positive image projection is formed on the substrate workbench. The first alignment mark and the second alignment mark are used to represent the alignment of the mask and the substrate.

2. The lithography system according to claim 1, characterized in that: Both the first catadioptric lens group and the second catadioptric lens group have the following lens arrangement structure, including: A first reflecting surface, a first lens group, a second lens group, a third lens group, a reflecting mirror, and a second reflecting surface. Among them, both the first lens group and the second lens group have positive optical power, and the third lens group includes at least one negative lens with negative optical power; The light from the object surface is reflected by the first reflecting surface and then passes through the first lens group, the second lens group, and the third lens group in sequence and then reaches the reflecting mirror. The light reflected by the reflecting mirror passes through the third lens group, the second lens group, and the first lens group in reverse sequence and then reaches the second reflecting surface, and is reflected by the second reflecting surface and then reaches the image surface.

3. The lithography system according to claim 2, characterized in that: The object surface of the first catadioptric lens group is located at the position of the mask on the mask workbench, and the image surface of the first catadioptric lens group coincides with the object surface of the second catadioptric lens group; The image surface of the second catadioptric lens group is located at the position of the substrate on the substrate workbench; The first catadioptric lens group and the second catadioptric lens group form a projection component for 1:1 positive image projection.

4. The photolithography system according to claim 2, characterized in that: Both the first catadioptric lens group and the second catadioptric lens group satisfy: 0.45 < F1 / L < 1.5, 0.45 < F2 / L < 1.05, where F1 is the combined focal length of the first lens group, F2 is the combined focal length of the second lens group, and L is the optical distance from the object surface to the reflecting surface of the reflecting mirror; And / or, the reflecting mirrors of both the first catadioptric lens group and the second catadioptric lens group have concave reflecting surfaces, and the radius of curvature R of the concave reflecting surface and the optical distance L from the object surface to the concave reflecting surface satisfy the following expression: 0.7 < -R / L < 1.5; And / or, the third lens group includes a positive optical power lens, a biconcave lens, and a positive optical power lens with a convex object side surface in sequence. The focal length f3 of the biconcave lens and the optical distance L from the object surface to the reflecting surface of the reflecting mirror satisfy the following expression: 0.15 < |f3| / L < 0.7; And / or, the lens closest to the first lens group in the second lens group is a positive focal length lens, and the curvature radius r21 of the object side surface of the positive focal length lens and the curvature radius r22 of its image side surface satisfy the following expression: 0 < |r21 / r22| < 0.5; And / or, the lens closest to the object surface in the first lens group is a biconvex lens, and the dispersion coefficient of the biconvex lens is defined as Vd1; the lens closest to the first lens group in the second lens group is a positive focal length lens, and the dispersion coefficient of the positive focal length lens is defined as Vd2; the third lens group includes multiple lenses, and the minimum dispersion coefficient of the negative lens among them is defined as Vd3, and the following relational expressions are satisfied: 20 < Vd1 - Vd2 < 55, 18 < Vd1 - Vd3 < 53; And / or, both the first catadioptric lens group and the second catadioptric lens group satisfy: 0.05 < Hy / F1 < 0.35, where Hy is the image height corresponding to the maximum field of view angle of the catadioptric lens group, and F1 is the combined focal length of the first lens group.

5. The photolithography system according to claim 2, characterized in that: The first lens group, the second lens group, the third lens group, and the reflector are arranged along the optical axis. The first reflecting surface and the second reflecting surface are two surfaces on the same reflector, and the first reflecting surface and the second reflecting surface are symmetrically distributed about the optical axis; the first reflecting surface and the second reflecting surface are both flat surfaces, and / or the first reflecting surface and the second reflecting surface both form an angle of 135° with the optical axis; The first lens group includes a first lens, the position of its image-side optical axis is convex, and it has a positive focal length; The second lens group includes a second lens, the position of its object-side optical axis is convex, and the position of its image-side optical axis is convex or concave; The third lens group includes a third lens, a fourth lens, and a fifth lens. The third lens is a biconvex lens, the fourth lens is a biconcave lens, and the fifth lens has a convex structure at the position of its object-side optical axis and a concave structure at the position of its image-side optical axis.

6. The photolithography system according to claim 1, characterized in that: The illumination component includes a light source, a homogenizing mirror, and a condenser lens. The homogenizing mirror uses a fly-eye integrator or a square rod integrator to homogenize the light beam emitted by the light source. The condenser lens focuses and transmits the homogenized light beam onto the mask located at the mask stage. The exit pupil position of the light beam emitted by the condenser lens coincides with the entrance pupil position of the projection component.

7. The photolithography system according to claim 6, characterized in that: The light source is a high-pressure mercury lamp or an LED lamp with one or more wavelengths, and the light beam emitted by it includes characteristic spectral lines of 365 nm, 405 nm, and 436 nm; The illumination component and the projection component remain stationary relative to the scanning stage; The exposure area output by the illumination component has a sharp corner structure in the vertical scanning direction.

8. The lithography system according to any one of claims 1 to 7, characterized in that: The optical system further includes an alignment position fine-tuning mechanism, which is installed between the mask stage and the first catadioptric lens group, or between the first catadioptric lens group and the second catadioptric lens group, or between the second catadioptric lens group and the substrate stage; The alignment position fine-tuning mechanism includes an optically transparent flat plate and an adjustment device. The adjustment device is configured to adjust the angle of the optically transparent flat plate relative to the scanning stage so that the projection of the first alignment mark on the substrate coincides with the second alignment mark.

9. A lithography method based on the lithography system according to claim 8, characterized in that: The following steps are involved: Placing a substrate to be photolithographically processed on a substrate workbench, and placing a corresponding mask on the mask workbench; Using the adjustment device of the alignment position fine adjustment mechanism to adjust the angle of the optical transparent flat plate relative to the scanning table of the photolithography system until the projection of the first alignment mark on the mask on the substrate coincides with the second alignment mark on the substrate; The light source of the photolithography system is controlled to emit i-line, h-line and / or g-line spectra, and a frame assembly of the photolithography system is driven to move along a scanning path on a scanning table through a planar driving mechanism, wherein the scanning path is related to an exposure pattern on the mask.

10. A 1:1 erect image projection system, characterized in that: The invention comprises two groups of first and second catadioptric mirror groups connected in series, wherein the first catadioptric mirror group and the second catadioptric mirror group have the same lens arrangement structure, including: A first reflecting surface, a first lens group, a second lens group, a third lens group, a reflecting mirror, and a second reflecting surface, wherein the first lens group and the second lens group both have positive optical power, and the third lens group includes at least one negative lens; The light from the object plane is reflected by the first reflection surface and then passes through the first mirror group, the second mirror group, and the third mirror group in sequence before reaching the reflection mirror. The light reflected by the reflection mirror passes through the third mirror group, the second mirror group, and the first mirror group in reverse order before reaching the second reflection surface, and then reaches the image plane after being reflected by the second reflection surface. Among them, the object plane of the first folding reflector group is located at the position of the optical mask in the lithography system, and the image plane of the first folding reflector group coincides with the object plane of the second folding reflector group; the image plane of the second folding reflector group is located at the position of the substrate to be projected in the lithography system; the first folding reflector group and the second folding reflector group form a 1:1 erect image projection.

Images