WO2020088033A1

WO2020088033A1 - Optical collimating system

Info

Publication number: WO2020088033A1
Application number: PCT/CN2019/100540
Authority: WO
Inventors: 郁毅敏; 郭银章; 王健
Original assignee: 上海微电子装备（集团）股份有限公司
Priority date: 2018-10-31
Filing date: 2019-08-14
Publication date: 2020-05-07
Also published as: TW202018332A; CN111123535A; CN111123535B; TWI716076B

Abstract

An optical collimating system, which is used to collimate a beam having a preset numerical aperture and a preset wavelength; the optical collimating system comprises a first plano-convex lens (L1), a first crescent-shaped convex lens (L2), a second crescent-shaped convex lens (L3), a third crescent-shaped convex lens (L4) and a first biconvex lens (5), which are located in sequence at a side of the object side.

Description

An optical collimating system

This disclosure requires the priority of the Chinese patent application filed on October 31, 2018, with the Chinese Patent Office, application number 201811288187.4. The entire contents of the above applications are incorporated by reference in this disclosure.

Technical field

The embodiments of the present invention relate to the technical field of optical setting, for example, to an optical collimating system.

Background technique

Optical lithography is a process in which a lithography machine uses optical projection exposure to etch the circuit device structure pattern on a mask plate onto a silicon wafer. The lithography machine is mainly composed of five parts: an exposure light source, an illumination system, a mask, a lithography projection objective, and a silicon wafer stage. In order to obtain higher lithographic resolution, the wavelength of the light emitted by the exposure light source is required to be developed in the deep ultraviolet or even extreme ultraviolet band. At the same time, the lithographic projection objective needs to have a high numerical aperture. Therefore, it is necessary to develop aberration detection technology for deep ultraviolet incident light and high numerical aperture projection lithography objectives.

In the polarization aberration test of the projection objective, the sensor module located on the mirror surface of the projection objective plays the role of checking the polarization state. The light emitted from the mirror surface of the projection object has a high numerical aperture, and the polarization element in the polarization aberration sensor can only work normally under the condition of parallel light or parallel-like light that deviates from parallel at a small angle, so an optical element is needed to Astigmatism converges into parallel light.

The collimator lens in the related art can usually condense visible light with a small numerical aperture, but it cannot condense the incident light of deep ultraviolet with high numerical aperture into parallel light.

Summary of the invention

In view of this, the embodiments of the present invention provide an optical collimating system to solve the technical problem of failing to condense the incident light with high numerical aperture and deep ultraviolet light into parallel light in the related art.

In a first aspect, an embodiment of the present invention provides an optical collimating system for collimating a beam with a preset numerical aperture and a preset wavelength. The optical collimating system includes a A plano-convex lens, a first meniscus convex lens, a second meniscus convex lens, a third meniscus convex lens and a first biconvex lens;

The power of the first plano-convex lens is D1, the power of the first meniscus convex lens is D2, the power of the second meniscus convex lens is D3, and the third meniscus shape The power of the convex lens is D4, and the power of the first biconvex lens is D5;

Among them, D1> 0, D2> 0, D3> 0, D4> 0, D5> 0, and

min {D3, D4, D5} represents the minimum value among D3, D4, and D5, and max {D3, D4, D5} represents the maximum value among D3, D4, and D5.

In a second aspect, an embodiment of the present invention provides an optical collimating system for collimating a beam with a preset numerical aperture and a preset wavelength. The optical collimating system includes a Two plano-convex lenses, fourth meniscus convex lenses, fifth meniscus convex lenses, and second biconvex lenses;

The power of the second plano-convex lens is D6, the power of the fourth meniscus convex lens is D7, the power of the fifth meniscus convex lens is D8, and the power of the second biconvex lens The optical power is D9;

Among them, D6> 0, D7> 0, D8> 0, D9> 0, and

min {D7, D8, D9} represents the minimum value among D7, D8, and D9, and max {D7, D8, D9} represents the maximum value among D7, D8, and D9.

In a third aspect, an embodiment of the present invention provides an optical collimating system for collimating a beam with a preset numerical aperture and a preset wavelength. The optical collimating system includes a Three plano-convex lens, sixth meniscus convex lens and third biconvex lens;

The power of the third plano-convex lens is D10, the power of the sixth meniscus convex lens is D11, and the power of the third biconvex lens is D12;

Among them, D10> 0, D11> 0, D12> 0, and

min {D11, D12} represents the minimum value among D11 and D12, and max {D11, D12} represents the maximum value among D11 and D12.

BRIEF DESCRIPTION

In order to more clearly explain the technical solutions of the exemplary embodiments herein, the following is a brief introduction to the drawings needed to describe the embodiments. Obviously, the drawings described are only some drawings of the embodiments to be described herein, but not all drawings. For those of ordinary skill in the art, without paying any creative work, other drawings can be obtained based on these drawings. Drawings.

1 is a schematic structural diagram of an optical collimation system provided by an embodiment of the present invention;

2 is a bar graph of low-order spherical aberration and low-order coma on each surface of the optical collimation system provided in FIG. 1;

3 is a schematic diagram of the relationship between the image-side collimation of the optical collimation system provided in FIG. 1 and the height of the object-side;

4 is an example diagram of the light aberration curve obtained after the optical collimating system provided in FIG. 1 is turned along the xy plane;

5 is a schematic structural diagram of another optical collimation system provided by an embodiment of the present invention;

6 is a schematic diagram of the relationship between the image-side collimation of the optical collimation system provided in FIG. 5 and the height of the object-side;

7 is an example diagram of the light aberration curve obtained after the optical collimating system provided in FIG. 5 is turned along the xy plane;

8 is a schematic structural diagram of yet another optical collimation system provided by an embodiment of the present invention;

9 is a schematic diagram of the relationship between the image-side collimation of the optical collimation system provided in FIG. 8 and the height of the object-side;

10 is an example diagram of the light aberration curve obtained after the optical collimating system provided in FIG. 8 is turned along the xy plane.

detailed description

The technical solutions herein will be described in detail through specific implementation manners in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are a part of the embodiments herein, but not all the embodiments.

The collimator lens in the related art usually can only condense visible light with a small numerical aperture (for example, less than 1), but it cannot condense high-aperture deep ultraviolet incident light into parallel light. Based on the above technical problems, an embodiment of the present invention provides an optical collimating system for collimating a beam with a preset numerical aperture and a preset wavelength, including a first plano-convex lens, a first A meniscus convex lens, a second meniscus convex lens, a third meniscus convex lens, and a first biconvex lens; the power of the first plano-convex lens is D1, and the power of the first meniscus convex lens is D2, the power of the second meniscus convex lens is D3, the power of the third meniscus convex lens is D4, and the power of the first biconvex lens is D5; wherein, D1> 0 , D2> 0, D3> 0, D4> 0, D5> 0, and

min {D3, D4, D5} represents the minimum value among D3, D4, and D5, and max {D3, D4, D5} represents the maximum value among D3, D4, and D5. Using the above technical solution, by reasonably setting the shape and power of each convex lens between the object surface and the image surface, the collimation of the optical collimation system provided by the embodiment of the present invention to a beam with a preset numerical aperture and a preset wavelength can be ensured The effect is good.

The above is an embodiment of this document, and the technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the drawings in the embodiments of the present invention.

FIG. 1 is a schematic structural diagram of an optical collimating system provided by an embodiment of the present invention. As shown in FIG. 1, the optical collimating system CL1 provided by an embodiment of the present invention can be used for beams with a preset numerical aperture and a preset wavelength For collimating operation, the optical collimating system CL1 includes a first plano-convex lens L1, a first meniscus convex lens L2, a second meniscus convex lens L3, a third meniscus convex lens L4 and a first Biconvex lens L5;

The power of the first plano-convex lens L1 is D1, the power of the first meniscus convex lens L2 is D2, the power of the second meniscus convex lens L3 is D3, and the power of the third meniscus convex lens L4 The degree is D4, and the power of the first lenticular lens L5 is D5;

Among them, D1> 0, D2> 0, D3> 0, D4> 0, D5> 0, and

As shown in FIG. 1, the optical collimating system CL1 provided by the embodiment of the present invention includes five lenses from the object surface to the image surface, which are a first plano-convex lens L1, a first meniscus convex lens L2, and a second meniscus convex lens L3, third meniscus convex lens L4 and first biconvex lens L5, first plano-convex lens L1, first meniscus convex lens L2, second meniscus convex lens L3, third meniscus convex lens L4 and first biconvex lens L5 all have positive power, that is D1> 0, D2> 0, D3> 0, D4> 0, D5> 0, where the power can represent the reciprocal of the effective focal length of the lens. Meanwhile, the power D1 of the first plano-convex lens L1, the power D3 of the second meniscus convex lens L3, the power D4 of the third meniscus convex lens L4, and the power D5 of the first biconvex lens L5 satisfy

min {D3, D4, D5} represents the minimum value among D3, D4, and D5, and max {D3, D4, D5} represents the maximum value among D3, D4, and D5. The purpose is to eliminate the second meniscus convex lens L3, The spherical aberration brought by the third meniscus convex lens L4 and the first biconvex lens L5 ensures that the optical collimating system has a good collimating effect on the incident beam.

In summary, the optical collimation system provided by the embodiments of the present invention includes the first plano-convex lens, the first meniscus convex lens, the second meniscus convex lens, and the third meniscus convex lens in this order And the first biconvex lens, the first plano-convex lens, the first meniscus convex lens, the second meniscus convex lens, the third meniscus convex lens and the first biconvex lens all have positive refractive power, and the first plano-convex lens has The power D1, the power D3 of the second meniscus convex lens, the power D4 of the third meniscus convex lens, and the power D5 of the first biconvex lens satisfy

Ensure that the optical collimation system provided by the embodiment of the present invention can collimate the incident beam with a preset numerical aperture and a preset wavelength, to ensure good collimation of the beam exiting the image plane, and to ensure that the image sensor needs to be parallel The light incident optical components can work normally, ensuring that the image-side sensor can accurately measure the image quality of light passing through the projection objective.

Optionally, the optical collimation system CL1 provided by the embodiment of the present invention may be applied to the case of immersing the projection objective. The immersion liquid may be water or oil. The embodiment of the present invention only uses the immersion liquid as water for illustration. As shown in FIG. 1, when the immersion liquid is water, the water can be used as a virtual lens L0, which is a biplanar lens. The incident point light source of the object plane is located on the surface S0 of the virtual lens L0, along the optical axis, as shown in FIG. In the Z direction, the distance between the virtual lens L0 and the first plano-convex lens L1 is very small, which is less than one third of the thickness of the first plano-convex lens L1. L1 surface.

Optionally, the difference between the power D5 of the first biconvex lens L5 and the power D4 of the third meniscus convex lens L4 satisfies the first preset condition, where the first preset condition may be the first double The difference between the power D5 of the convex lens L5 and the power D4 of the third meniscus convex lens L4 is zero or a small value close to zero; the power D4 of the third meniscus convex lens L4 and the first The difference between the power D3 of the second meniscus convex lens L3 satisfies the second preset condition, where the second preset condition may be the power D4 of the third meniscus convex lens L4 and the second meniscus convex lens The difference between the power D3 of L3 is zero or a smaller value close to zero. In this way, | D5-D4 | ≈ | D4-D3 | ≈0, the power D3 of the second meniscus convex lens L3, the power D4 of the third meniscus convex lens L4, and the power of the first biconvex lens L5 can be guaranteed The power D5 changes uniformly, ensuring that the second meniscus convex lens L3, the third meniscus convex lens L4, and the first biconvex lens L5 can achieve the effects of eliminating aberrations and converging light uniformly.

Optionally, the first plano-convex lens L1 includes a first surface S1 close to the object plane and a second surface S2 away from the object plane, and the first meniscus convex lens L2 includes a third surface S3 close to the object plane And the fourth surface S4 away from the object side, the second meniscus convex lens L3 includes a fifth surface S5 near the object side and the sixth surface S6 away from the object side, and the third meniscus convex lens L4 includes A seventh surface S7 close to the object surface side and an eighth surface S8 far from the object surface side, the first lenticular lens L5 includes a ninth surface S9 close to the object surface side and a tenth surface S10 far from the object surface side; Among them, the first surface S1 is a plane; the second surface S2 is a super hemispherical surface, and the second surface S2 is a Qiming surface, the super hemispherical surface includes a hemispherical surface and two end points of the hemispherical surface extend a predetermined distance in the optical axis direction The formed outer surface; the third surface S3, the fourth surface S4, the fifth surface S5, the sixth surface S6, the seventh surface S7, the eighth surface S8, the ninth surface S9 and the tenth surface S10 are all spherical, and the The fifth surface S5 is the Qiming surface, and the tenth surface S10 is the diaphragm surface of the optical collimation system.

Exemplarily, with continued reference to FIG. 1, setting the first surface S1 as a plane can ensure that the immersion liquid flows freely on the first surface S1 without aberration. Set the second surface S2 as a super hemispherical surface and a clear surface to ensure that the spherical aberration and coma generated by the second surface S2 are very small and can be neglected. Among them, the super hemispherical surface can be understood as the hemispherical surface and the two hemispherical surfaces. The outer surface formed by each end point extending a preset distance in the optical axis direction. The third surface S3, the fourth surface S4, the fifth surface S5, the sixth surface S6, the seventh surface S7, the eighth surface S8, the ninth surface S9 and the tenth surface S10 are all spherical, and the fifth surface S5 is Qi Ming surface, the tenth surface S10 is the diaphragm surface of the optical collimation system, which can ensure that each surface has a good convergence effect on the light, the spherical aberration and coma generated can be ignored, and the collimation effect of the optical collimation system is guaranteed good.

Specifically, FIG. 2 is a bar graph of low-order spherical aberration and low-order coma of each surface of the optical collimation system provided in FIG. 1, the abscissa represents the surface number of each mirror surface, and the ordinate represents the aberration coefficient. As shown in FIG. 2, the first surface S1 is a flat surface, which does not produce spherical aberration and coma; the second surface S2 is a super hemispherical surface and is a luminous surface, and its spherical aberration of each order is small and does not produce coma; The fifth surface S5 is a Qiming surface, and its spherical aberration of each order is small and does not produce coma; at the same time, the spherical aberration and coma values produced by each surface can be cancelled positively and negatively to ensure the spherical aberration and The coma is small and can be ignored to ensure that the collimation effect of the optical collimation system is good.

Optionally, in the optical collimating system CL1 provided by the embodiment of the present invention, the preset numerical aperture may be NA, where NA> 0; the preset wavelength may be λ, where λ = 193.368 nm, which is an embodiment of the present invention The provided optical collimation system can use a deep ultraviolet light source with a wavelength of 193.368 nanometers, and the numerical aperture of the object side satisfies a large numerical aperture value, for example, the numerical aperture NA can be 1.35, which ensures that a higher lithographic resolution can be achieved.

Optionally, the preparation materials of the first plano-convex lens L1, the first meniscus convex lens L2, the second meniscus convex lens L3, the third meniscus convex lens L4, and the first biconvex lens L5 may include fused silica, whose refractive index It is 1.5602, the immersion liquid can be water, and its refractive index is 1.436157.

Table 1 exemplarily shows the parameter values of each optical element of the optical collimation system CL1 as described in FIG. 1 provided by an embodiment of the present invention, where the column of "Serial Number" indicates the distance from the object plane to the image plane The serial number corresponding to each surface; the "radius" column gives the spherical radius of each surface; the "thickness / spacing" column indicates the apex distance between adjacent surfaces. In the lens, this value indicates the thickness of the lens; The "material" column gives the material between each surface and the next surface. Here, the material of the lens is fused quartz and the immersion liquid is water.

Table 1

The optical collimation system provided by the embodiment of the present invention uses a light source with a wavelength of 193.368 nm, the object-side numerical aperture NA = 1.35 and each parameter shown in Table 1 can ensure that the beam received by the image side is parallel light. In a small field of view, the collimation of parallel light can be less than 0.5 °, the effective focal length of the object side is 5.0834mm, and the F number is 0.37. The F number is defined as the ratio of the effective focal length of the object side and the diameter of the entrance pupil. The total length of the optical collimating system is 13.2mm, which ensures that the entire optical collimating system has a good collimating effect, and at the same time, the entire optical collimating system has a compact structure and good performance.

It should be noted that Table 1 only exemplarily provides the parameter values of each optical element in the optical collimating system CL1. It can be understood that when the parameter values of each optical element in the optical collimating system are shown in Table 1 The parameter value obtained by the proportional scaling of the value of is also within the protection scope of the embodiment of the present invention.

FIG. 3 is a schematic diagram of the relationship between the image-side collimation of the optical collimation system provided in FIG. 1 and the height of the object side. The image-side collimation is defined as the angle between the exit light of the image side and the optical axis (z-axis). As shown in Figure 3, the deviation of the collimation of the ray of the image side at the outermost edge of the meridian (+ Y, -Y) and the chief ray becomes larger as the height of the object side increases, but the collimation degree within 20 μm of the object side height The maximum deviation of is controlled within 0.25 °, with good collimation.

4 is an example diagram of the light aberration curve obtained after the optical collimating system provided in FIG. 1 is flipped along the xy plane, wherein the vertical axis unit is mm, and the horizontal axis is along the diameter direction of the pupil plane. The three coordinates from top to bottom sequentially correspond to the object heights of 13 μm, 6.5 μm, and 0 μm in FIG. 1. It can be seen from the figure that the optical collimation system provided by the embodiments of the present invention has better image quality in the range of -59.6 nm-+59.6 nm (0.3 wavelengths).

It is understandable that the meridian plane refers to the plane formed by the principal ray of the off-axis object point and the main axis of the optical collimation system; the sagittal plane refers to the principal ray of the off-axis object point, and A plane perpendicular to the meridian plane.

It should be noted that in FIG. 4, the relative field height (Relative Field Height) refers to the ratio of the image height position to the total image height length (that is, the image height position / total image height length). According to Fig. 4, at the first image height position, the relative field of view height is 1, and the angle between the parallel light rays at the object side of the corresponding collimator and the optical axis is 0.15 °; at the second image height position, the relative field of view The height is 0.5, and the angle between the parallel rays of the object side of the corresponding collimator lens and the optical axis is 0.075 °; at the third image height, the relative field height is 0, and the object side of the corresponding collimator lens is The angle between the parallel rays and the optical axis is 0 °.

FIG. 5 is a schematic structural diagram of another optical collimating system provided by an embodiment of the present invention. As shown in FIG. 5, the optical collimating system CL2 provided by an embodiment of the present invention can be used for a preset numerical aperture and a preset wavelength. The light beam is collimated, and the optical collimation system CL2 includes a second plano-convex lens L6, a fourth meniscus convex lens L7, a fifth meniscus convex lens L8, and a second biconvex lens L9, which are sequentially positioned on the object side;

The power of the second plano-convex lens L6 is D6, the power of the fourth meniscus convex lens L7 is D7, the power of the fifth meniscus convex lens L8 is D8, and the power of the second biconvex lens L9 is D9;

Among them, D6> 0, D7> 0, D8> 0, D9> 0, and

As shown in FIG. 5, the optical collimation system CL2 provided by the embodiment of the present invention includes four lenses from the object surface to the image surface, which are a second plano-convex lens L6, a fourth meniscus convex lens L7, and a fifth meniscus convex lens L8, and the second biconvex lens L9, the second plano-convex lens L6, the fourth meniscus convex lens L7, the fifth meniscus convex lens L8 and the second biconvex lens L9 all have positive refractive power, ie D6> 0, D7> 0 , D8> 0, D9> 0. Meanwhile, the power D6 of the second plano-convex lens L6, the power D7 of the fourth meniscus convex lens L7, the power D8 of the fifth meniscus convex lens L8, and the power D9 of the second biconvex lens L9 satisfy

min {D7, D8, D9} represents the minimum value among D7, D8, and D9, and max {D7, D8, D9} represents the maximum value among D7, D8, and D9. The purpose is to eliminate the fourth meniscus convex lens L7, The spherical aberration brought by the fifth meniscus convex lens L8 and the second biconvex lens L9 ensures that the optical collimating system has a good collimating effect on the incident beam.

In summary, the optical collimation system provided by the embodiments of the present invention is provided by sequentially placing a second plano-convex lens, a fourth meniscus convex lens, a fifth meniscus convex lens, and a second biconvex lens in order between the object plane and the image plane. The second plano-convex lens, the fourth meniscus convex lens, the fifth meniscus convex lens, and the second biconvex lens all have positive power, and the power of the second plano-convex lens L6, D6, and the light of the fourth meniscus convex lens L7 The power D7, the power D8 of the fifth meniscus convex lens L8 and the power D9 of the second biconvex lens L9 satisfy

Ensure that the optical collimation system provided by the embodiment of the present invention can collimate the incident beam with a preset numerical aperture and a preset wavelength, ensure that the beam exiting the image plane has good collimation, and ensure that the image sensor Optical components that require parallel light incidence can work normally to ensure that the image-side sensor can accurately measure the image quality of light passing through the projection objective.

Optionally, the optical collimation system CL2 provided by the embodiment of the present invention may be applied to the case of immersing the projection objective. The immersion liquid may be water or oil. The embodiment of the present invention only uses the immersion liquid as water for illustration. As shown in FIG. 5, when the immersion liquid is water, the water can be used as the virtual lens L0, which is a double plane lens. The incident point light source of the object plane is located on the surface S0 of the virtual lens L0, along the optical axis, as shown in FIG. 5. In the Z direction, the distance between the virtual lens L0 and the second plano-convex lens L6 is very small, which is much smaller than the thickness of the second plano-convex lens L6. Therefore, the object point incident point light source can also be considered approximately on the surface of the second plano-convex lens L6.

Optionally, the difference between the power D9 of the second biconvex lens L9 and the power D8 of the fifth meniscus convex lens L8 satisfies the third preset condition, where the third preset condition may be the second double The difference between the power D9 of the convex lens L9 and the power D8 of the fifth meniscus convex lens L8 is zero or a smaller value close to zero; the power D8 of the fifth meniscus convex lens L8 and the first The difference between the power D7 of the four meniscus convex lens L7 satisfies the fourth preset condition, where the fourth preset condition may be the power D8 of the fifth meniscus convex lens L8 and the fourth meniscus convex lens The difference between the optical power D7 of L7 is zero or a smaller value close to zero, so that | D9-D8 | ≈ | D8-D7 | ≈0, and the optical power of the fourth meniscus convex lens L7 can be guaranteed Degree D7, the power D8 of the fifth meniscus convex lens L8 and the power D9 of the second biconvex lens L9 change uniformly, ensuring the fourth meniscus convex lens L7, the fifth meniscus convex lens L8 and the second biconvex lens L9 can achieve the effect of eliminating aberrations and converging light evenly.

Optionally, the second plano-convex lens L6 includes an eleventh surface S11 close to the object surface side and a twelfth surface S12 away from the object surface side, and the fourth meniscus convex lens L7 includes a tenth surface close to the object surface side The three surfaces S13 and the fourteenth surface S14 away from the object surface, the fifth meniscus convex lens L8 includes a fifteenth surface S15 near the object surface and a sixteenth surface S16 away from the object surface, the second The lenticular lens L9 includes a seventeenth surface S17 near the object surface and an eighteenth surface S18 away from the object surface; wherein, the eleventh surface S11 is a plane; the twelfth surface S12 is a hyperhemispherical surface, and the The twelve surface S12 is a Qiming surface, and the super hemispherical surface includes a hemispherical surface and two end points of the hemispherical surface extending at a predetermined distance in the optical axis direction; a thirteenth surface S13, a fourteenth surface S14, and a tenth surface The fifth surface S15, the sixteenth surface S16, the seventeenth surface S17, and the eighteenth surface S18 are spherical surfaces, and the eighteenth surface S18 is an aperture surface of the optical collimation system CL2.

Exemplarily, with continued reference to FIG. 5, setting the eleventh surface S11 as a plane can ensure that the immersion water flows freely on the eleventh surface S11 without aberration. The twelfth surface S12 is set as a super hemispherical surface and a clear surface, to ensure that the spherical aberration and coma generated by the twelfth surface S12 are small and can be ignored, where the super hemispherical surface can be understood as a hemispherical surface and a hemispherical surface The two endpoints of the outer surface formed after extending a predetermined distance in the direction of the optical axis. The thirteenth surface S13, the fourteenth surface S14, the fifteenth surface S15, the sixteenth surface S16, the seventeenth surface S17 and the eighteenth surface S18 are all spherical, and the eighteenth surface S18 is an optical collimating system The diaphragm surface of CL2 can ensure that each surface has a good convergence effect on the light, and the spherical aberration and coma generated can be ignored, and the collimation effect of the optical collimation system is good.

Optionally, in the optical collimation system CL2 provided by the embodiment of the present invention, the preset numerical aperture may be NA, where NA> 0; the preset wavelength may be λ, where λ = 193.368 nm, which is an embodiment of the present invention The provided optical collimation system can use a deep ultraviolet light source with a wavelength of 193.368 nanometers, and the numerical aperture of the object side satisfies a large numerical aperture value, for example, the numerical aperture NA can be 1.35, which ensures that a higher lithographic resolution can be achieved.

Optionally, the preparation materials of the second plano-convex lens L6, the fourth meniscus convex lens L7, the fifth meniscus convex lens L8, and the second biconvex lens L9 may include fused silica, whose refractive index is 1.5602, and the immersion liquid may be water , Its refractive index is 1.436157.

Table 2 exemplarily shows the parameter values of each optical element of the optical collimating system CL2 as described in FIG. 5 provided by an embodiment of the present invention, where the column of “Serial Number” represents the distance from the object plane to the image plane The serial number corresponding to each surface; the "radius" column gives the spherical radius of each surface; the "thickness / spacing" column indicates the apex distance between adjacent surfaces. In the lens, this value indicates the thickness of the lens; The "material" column gives the material between each surface and the next surface. Here, the material of the lens is fused quartz and the immersion liquid is water.

Table 2

The optical collimation system provided by the embodiment of the present invention uses a light source with a wavelength of 193.368 nm, and the object-side numerical aperture NA = 1.35 and using each parameter shown in Table 2, can ensure that the beam received by the image side is parallel light. The square effective focal length is 4.8mm, and the F number is 0.35. The F number is defined as the ratio of the effective focal length of the object side to the diameter of the entrance pupil. The total length of the optical collimation system is 11mm, which ensures that the entire optical collimation system has a good collimation effect. At the same time, the entire optical collimation system has a compact structure and good performance.

It should be noted that Table 2 only exemplarily provides the parameter values of each optical element in the optical collimating system CL2. It can be understood that when the parameter values of each optical element in the optical collimating system are shown in Table 2 The parameter value obtained by the proportional scaling of the value of is also within the protection scope of the embodiment of the present invention.

FIG. 6 is a schematic diagram of the relationship between the image-side collimation of the optical collimation system provided in FIG. 5 and the height of the object side. The image-side collimation is defined as the angle between the exit light of the image side and the optical axis (z-axis). As shown in Fig. 6, the deviation of the collimation of the positive ray + Y and the principal ray of the ray on the image side increases with the height of the object side, and the deviation of the collimation on the negative edge -Y of the meridian As the height of the object side decreases, the maximum deviation of collimation within 20 μm of the object side is controlled within 0.36 °, which has good collimation.

7 is an example diagram of the light aberration curve obtained after the optical collimating system provided in FIG. 5 is flipped along the xy plane, where the vertical axis unit is mm, and the horizontal axis is along the diameter direction of the pupil plane. The three coordinates from top to bottom correspond to the object heights of 16 μm, 8 μm, and 0 μm in sequence in FIG. 5. It can be seen from the figure that the non-edge rays of the optical collimation system provided by the embodiments of the present invention have aberrations of less than 1 wavelength in the three fields of view shown in FIG. 7, and the imaging quality is better.

It should be noted that, in FIG. 7, the relative field height (Relative Field Height) refers to the ratio of the image height position to the total image height length (that is, the image height position / total image height length). According to Fig. 7, at the first image height position, the relative field of view height is 1, and the angle between the parallel light rays at the object side of the corresponding collimator and the optical axis is 0.2 °; at the second image height position, the relative field of view The height is 0.5, and the angle between the parallel rays of the object side of the corresponding collimator and the optical axis is 0.1 °; at the third image height, the relative field height is 0, and the object side of the corresponding collimator is The angle between the parallel rays and the optical axis is 0 °. FIG. 8 is a schematic structural diagram of another optical collimating system provided by an embodiment of the present invention. As shown in FIG. 8, the optical collimating system CL3 provided by the embodiment of the present invention can be used for preset numerical aperture and preset wavelength. The light beam is collimated, and the optical collimating system CL3 includes a third plano-convex lens L10, a sixth meniscus convex lens L11, and a third biconvex lens L12, which are located on the side of the object plane in sequence;

The power of the third plano-convex lens L10 is D10, the power of the sixth meniscus convex lens L11 is D11, and the power of the third biconvex lens L12 is D12;

Among them, D10> 0, D11> 0, D12> 0, and

As shown in FIG. 8, the optical collimating system CL3 provided by the embodiment of the present invention includes three lenses from the object plane to the image plane, which are a third plano-convex lens L10, a sixth meniscus convex lens L11, and a third biconvex lens L12. The third plano-convex lens L10, the sixth meniscus convex lens L11, and the third biconvex lens L12 all have positive refractive power, that is, D10> 0, D11> 0, D12> 0. Meanwhile, the power D10 of the third plano-convex lens L10, the power D11 of the sixth meniscus convex lens L11, and the power D12 of the third biconvex lens L12 satisfy

min {D11, D12} represents the minimum value of D11 and D12, max {D11, D12} represents the maximum value of D11 and D12, the purpose is to eliminate the sixth meniscus convex lens L11 and the third biconvex lens L12 Spherical aberration ensures that the optical collimation system collimates the incident beam well.

In summary, the optical collimation system provided by the embodiment of the present invention includes the third plano-convex lens, the sixth meniscus convex lens and the third biconvex lens in order between the object plane and the image plane, and the Both the meniscus convex lens and the third biconvex lens have positive power, and the power D10 of the third plano-convex lens L10, the power D11 of the sixth meniscus convex lens L11, and the power D12 of the third biconvex lens L12 Satisfy

Optionally, the optical collimation system CL3 provided by the embodiment of the present invention may be applied to the case of immersing the projection objective. The immersion liquid may be water or oil. The embodiment of the present invention only uses the immersion liquid as water for illustration. As shown in FIG. 8, when the immersion liquid is water, the water can be used as the virtual lens L0, which is a double plane lens. The incident point light source of the object plane is located on the surface S0 of the virtual lens L0, along the optical axis, as shown in FIG. 8 In the Z direction, the distance between the virtual lens L0 and the third plano-convex lens L10 is very small, which is much smaller than the thickness of the third plano-convex lens L10, so the object plane incident point light source can also be considered approximately on the surface of the third plano-convex lens L10.

Optionally, the third plano-convex lens L10 includes a nineteenth surface S19 close to the object side and a twentieth surface S20 away from the object side, and the sixth meniscus convex lens L11 includes a second close to the object side The eleventh surface S21 and the twenty-second surface S22 away from the object surface. The third lenticular lens L12 includes a twenty-third surface S23 near the object surface and a twenty-fourth surface S24 away from the object surface. Among them, the nineteenth surface S19 is a plane; the twentieth surface S20 is a super hemispherical surface, and the twentieth surface S20 is a Qiming surface. The super hemispherical surface includes a hemispherical surface and two end points of the hemispherical surface extend in the optical axis The outer surface formed by the preset distance; the twenty-first surface S21, the twenty-second surface S22, and the twenty-third surface S23 are spherical, the twenty-fourth surface S24 is aspheric, and the twenty-fourth surface S24 is optical Aperture surface of straight system CL3.

Exemplarily, with continued reference to FIG. 8, setting the nineteenth surface S19 as a plane can ensure that the immersion water flows freely on the nineteenth surface S19 without aberration. Set the twentieth surface S20 as a super hemispherical surface and a clear surface, to ensure that the spherical aberration and coma generated by the twentieth surface S20 are small and can be ignored, where the super hemispherical surface can be understood as a hemispherical surface and hemispherical surface The two endpoints of the outer surface formed after extending a predetermined distance in the direction of the optical axis. The twenty-first surface S21, the twenty-second surface S22, and the twenty-third surface S23 are all spherical, the twenty-fourth surface S24 is aspheric, and the twenty-fourth surface S24 is the diaphragm of the optical collimation system CL3 The surface can ensure that each surface has a good convergence effect on light, and the generated spherical aberration and coma can be ignored, ensuring that the collimation effect of the optical collimation system is good.

Optionally, the diaphragm surface (S24) in the optical collimation system CL3 provided by the embodiment of the present invention is an aspherical surface, and the twenty-fourth surface S24 can be described by the following formula:

Among them, P is the function of the height of the arch, h is the height from the point on the lens to the optical axis, K and C1 to Cn are the coefficients of the aspheric terms, and R is the radius of the highest point.

Optionally, in the optical collimation system CL3 provided by the embodiment of the present invention, the preset numerical aperture may be NA, where NA> 0; the preset wavelength may be λ, where λ = 193.368 nm, which is an embodiment of the present invention The provided optical collimation system can use a deep ultraviolet light source with a wavelength of 193.368 nanometers, and the numerical aperture of the object side satisfies a large numerical aperture value, for example, the numerical aperture NA can be 1.35, which ensures that a higher lithographic resolution can be achieved.

Optionally, the preparation materials of the third plano-convex lens L10, the sixth meniscus convex lens L11, and the third biconvex lens L12 may include fused silica, whose refractive index is 1.5602, and the immersion liquid may be water, and its refractive index is 1.436157.

Table 3 exemplarily shows the parameter values of each optical element of the optical collimation system CL3 as described in FIG. 8 provided by an embodiment of the present invention, where the column of "Serial Number" indicates the distance from the object plane to the image plane The serial number corresponding to each surface; the "radius" column gives the spherical radius of each surface; the "thickness / spacing" column indicates the apex distance between adjacent surfaces. In the lens, this value indicates the thickness of the lens; The "material" column gives the material between each surface and the next surface. Here, the material of the lens is fused quartz and the immersion liquid is water.

table 3

The optical collimation system provided by the embodiment of the present invention uses a light source with a wavelength of 193.368 nanometers, and the object-side numerical aperture NA = 1.35 and using each parameter shown in Table 3 can ensure that the beam received by the image side is parallel light. The square effective focal length is 4.8mm, and the F number is 0.37. The F number is defined as the ratio of the effective focal length of the object side to the diameter of the entrance pupil. The total length of the optical collimation system is 12mm, which ensures that the entire optical collimation system has a good collimation effect. At the same time, the entire optical collimation system has a compact structure and good performance.

It should be noted that Table 3 only exemplarily provides the parameter values of each optical element in the optical collimating system CL3. It can be understood that when the parameter values of each optical element in the optical collimating system are shown in Table 3 The parameter value obtained by the proportional scaling of the value of is also within the protection scope of the embodiment of the present invention.

9 is a schematic diagram of the relationship between the image-side collimation of the optical collimation system provided in FIG. 8 and the height of the object side. The image-side collimation is defined as the angle between the exit light of the image side and the optical axis (z-axis). As shown in Fig. 9, the deviation of the collimation of the ray of the image side at the outermost edge of the meridian (+ Y, -Y) and the chief ray becomes larger as the height of the object side increases, but the collimation degree within 20 μm of the object side height The maximum deviation of is controlled within 0.25 °, with good collimation.

FIG. 10 is an example diagram of the light aberration curve obtained by the optical collimating system provided in FIG. 8 after being flipped along the xy plane, where the vertical axis unit is mm, and the abscissa is along the diameter direction of the pupil plane. The three coordinates from top to bottom correspond to the object heights of 16 μm, 8 μm, and 0 μm in sequence in FIG. 8. It can be seen from the figure that the optical collimating system provided by the embodiments of the present invention has better image quality in the range of -22.7nm- + 22.7nm (0.12 wavelengths).

It should be noted that in FIG. 10, the relative field height (Relative Field Height) refers to the ratio of the image height position to the total image height length (that is, the image height position / total image height length). According to FIG. 10, at the first image height position, the relative field of view height is 1, and the angle between the parallel light rays at the object side of the corresponding collimator and the optical axis is 0.2 °; at the second image height position, the relative field of view The height is 0.5, and the angle between the parallel rays of the object side of the corresponding collimator and the optical axis is 0.1 °; at the third image height, the relative field height is 0, and the object side of the corresponding collimator is The angle between the parallel rays and the optical axis is 0 °.

Claims

An optical collimating system is used to collimate a beam with a preset numerical aperture and a preset wavelength. The optical collimating system includes a first plano-convex lens (L1) and a first bend that are sequentially positioned on the side of the object plane Convex lens (L2), second meniscus lens (L3), third meniscus lens (L4) and first biconvex lens (L5);

The power of the first plano-convex lens (L1) is D1, the power of the first meniscus convex lens (L2) is D2, and the power of the second meniscus convex lens (L3) is D3, the power of the third meniscus convex lens (L4) is D4, and the power of the first biconvex lens (L5) is D5;

Among them, D1> 0, D2> 0, D3> 0, D4> 0, D5> 0, and

min {D3, D4, D5} represents the minimum value among D3, D4, and D5, and max {D3, D4, D5} represents the maximum value among D3, D4, and D5.
The optical collimating system according to claim 1, wherein the difference between the power D5 of the first lenticular lens (L5) and the power D4 of the third meniscus convex lens (L4) The first preset condition is satisfied, and the first preset condition is that the difference between the power D5 of the first biconvex lens (L5) and the power D4 of the third meniscus convex lens (L4) is zero; The difference between the power D4 of the third meniscus convex lens (L4) and the power D3 of the second meniscus convex lens (L3) satisfies the second preset condition, and the second preset condition is The difference between the power D4 of the three meniscus convex lens (L4) and the power D3 of the second meniscus convex lens (L3) is zero.
The optical collimating system according to claim 1, wherein the first plano-convex lens (L1) includes a first surface (S1) close to the object plane and a second surface far away from the object plane (S2), the first meniscus convex lens (L2) includes a third surface (S3) close to the object surface side and a fourth surface (S4) away from the object surface side, the second The meniscus convex lens (L3) includes a fifth surface (S5) close to the object surface side and a sixth surface (S6) away from the object surface side, and the third meniscus convex lens (L4) includes A seventh surface (S7) close to the object surface side and an eighth surface (S8) far from the object surface side, the first lenticular lens (L5) includes a ninth surface close to the object surface side The surface (S9) and the tenth surface (S10) away from the object surface;

Wherein, the first surface (S1) is a plane; the second surface (S2) is a super hemispherical surface, and the second surface (S2) is a Qiming surface, the super hemispherical surface includes a hemispherical surface and the hemispherical surface The two end points of the surface extend an outer surface formed by a predetermined distance in the optical axis direction; the third surface (S3), the fourth surface (S4), the fifth surface (S5), the sixth The surface (S6), the seventh surface (S7), the eighth surface (S8), the ninth surface (S9), and the tenth surface (S10) are spherical, and the fifth surface ( S5) is the Qiming surface, and the tenth surface (S10) is the diaphragm surface of the optical collimation system.
The optical collimating system according to claim 1, wherein the first plano-convex lens (L1), the first meniscus convex lens (L2), the second meniscus convex lens (L3), the The preparation materials of the third meniscus convex lens (L4) and the first biconvex lens (L5) include fused quartz.
An optical collimating system is used to collimate a beam with a preset numerical aperture and a preset wavelength. The optical collimating system includes a second plano-convex lens (L6) and a fourth bend that are sequentially positioned on the side of the object plane Lunar convex lens (L7), fifth meniscus convex lens (L8) and second biconvex lens (L9);

The power of the second plano-convex lens (L6) is D6, the power of the fourth meniscus convex lens (L7) is D7, the power of the fifth meniscus convex lens (L7) is D8, the power of the second lenticular lens (L9) is D9;

Among them, D6> 0, D7> 0, D8> 0, D9> 0, and

min {D7, D8, D9} represents the minimum value among D7, D8, and D9, and max {D7, D8, D9} represents the maximum value among D7, D8, and D9.
The optical collimating system according to claim 5, wherein the difference between the power D9 of the second lenticular lens (L9) and the power D8 of the fifth meniscus convex lens (L8) The third preset condition is satisfied, and the third preset condition is that the difference between the power D9 of the second lenticular lens (L9) and the power D8 of the fifth meniscus convex lens (L8) is zero; The difference between the power D8 of the fifth meniscus convex lens and the power D7 of the fourth meniscus convex lens satisfies the fourth preset condition, and the fourth preset condition is the fifth meniscus convex lens ( The difference between the power D8 of L8) and the power D7 of the fourth meniscus convex lens (L7) is zero.
The optical collimating system according to claim 6, wherein the second plano-convex lens (L6) includes an eleventh surface (S11) close to the object surface side and a tenth surface away from the object surface side Two surfaces (S12); the fourth meniscus convex lens (L7) includes a thirteenth surface (S13) close to the object surface side and a fourteenth surface (S14) away from the object surface side, The fifth meniscus convex lens (L8) includes a fifteenth surface (S15) close to the object surface side and a sixteenth surface (S16) away from the object surface side, the second biconvex lens (L9) includes a seventeenth surface (S17) close to the object surface side and an eighteenth surface (S18) away from the object surface side;

Wherein, the eleventh surface (S11) is a plane; the twelfth surface (S12) is a super hemispherical surface, and the twelfth surface (S12) is a Qiming surface, the super hemispherical surface includes a hemispherical surface and The two end points of the hemispherical surface extend an outer surface formed by a preset distance in the optical axis direction; the thirteenth surface (S13), the fourteenth surface (S14), the fifteenth surface (S15) ), The sixteenth surface (S16), the seventeenth surface (S17) and the eighteenth surface (S18) are spherical, and the eighteenth surface (S18) is the optical collimating system Diaphragm face.
The optical collimating system according to claim 5, wherein the second plano-convex lens (L6), the fourth meniscus convex lens (L6), the fifth meniscus convex lens (L8) and the The preparation material of the second lenticular lens (L9) includes fused quartz.
An optical collimating system is used to collimate a beam with a preset numerical aperture and a preset wavelength. The optical collimating system includes a third plano-convex lens (L10) and a sixth bend that are sequentially positioned on the side of the object plane Lunar convex lens (L11) and third biconvex lens (L12);

The power of the third plano-convex lens (L10) is D10, the power of the sixth meniscus convex lens (L11) is D11, and the power of the third biconvex lens (L12) is D12;

Among them, D10> 0, D11> 0, D12> 0, and
min {D11, D12} represents the minimum value among D11 and D12, and max {D11, D12} represents the maximum value among D11 and D12.
The optical collimating system according to claim 9, wherein the third plano-convex lens (L10) includes a nineteenth surface (S19) close to the object side and a second away from the object side Ten surfaces (S20); the sixth meniscus convex lens (L11) includes a twenty-first surface (S21) close to the object surface side and a twenty-second surface (S22) away from the object surface side ), The third lenticular lens (L12) includes a twenty-third surface (S23) close to the object surface side and a twenty-fourth surface (S24) away from the object surface side;

Wherein, the nineteenth surface (S19) is a plane; the twentieth surface (S20) is a super hemispherical surface, and the twentieth surface (S20) is a Qiming surface, and the super hemispherical surface includes a hemispherical surface and The two end points of the hemispherical surface extend an outer surface formed by a preset distance in the optical axis direction; the twenty-first surface (S21), the twenty-second surface (S22), and the twenty-third The surface (S23) is a spherical surface, the twenty-fourth surface (S24) is an aspheric surface, and the twenty-fourth surface (S24) is an aperture surface of the optical collimation system.
The optical collimating system according to claim 9, wherein the preparation materials of the third plano-convex lens (L10), the sixth meniscus convex lens (L11), and the third biconvex lens (L12) include fusion quartz.
The optical collimating system according to any one of claims 1-11, wherein the preset numerical aperture is NA, where NA> 0;

The preset wavelength is λ, where λ = 193.368 nm.