CN115524927A - Large-view-field projection objective and photoetching machine - Google Patents

Abstract

The invention provides a large-view-field projection objective and a photoetching machine. The invention only uses four groups of lens groups, so that the optical structure is more compact, the cost is reduced, and the transmittance of the projection objective system is improved, thereby improving the exposure efficiency. In addition, a focal length f of the first lens group ₁ Focal length f of the second lens group ₂ A focal length f of the third lens group ₃ And a focal length f of the fourth lens group ₄ Satisfies 1.06<|f1/f2|<1.26；1.76<|f2/f3|<1.90；1.80<|f3/f4|<2.00；3.85<|f1/f4|<4.25, e.g.This configuration enables to achieve a high resolution while achieving an enlarged exposure field of view.

Description

Large field of view projection objective lens and photolithography machine

technical field

The invention relates to the field of optical technology, in particular to a projection objective lens with a large field of view and a photolithography machine.

Background technique

Optical projection lithography is an optical exposure process that uses the principle of optical projection imaging to transfer the pattern on the mask plate to the substrate (such as a silicon wafer coated with photoresist) in a distributed repeating or scanning manner. Usually, the resolution of lithography can be achieved by shortening the wavelength, increasing the numerical aperture, and reducing the process factor. With the continuous improvement of integrated circuit device integration, higher requirements are put forward for the resolution of lithography objective lens. Limited by the space constraints of the overall machine volume, and under the condition that the exposure performance of the large-field-of-view projection lens is not affected, lithography technology has increasingly strict requirements on the volume of the large-field-of-view projection lens. Small size, compact structure, excellent performance, and reasonable cost of lithography large-field projection objective lens have increasingly become a trend and need for technological development.

In the prior art, on the one hand, there are more lenses in the projection objective lens system with a large field of view, but more lenses will cause the lenses to absorb the energy of the system, thereby reducing the total transmittance of the objective lens; on the other hand On the one hand, there are problems such as small numerical aperture and low resolution, and there is a contradiction between the diameter of the exposure field of view and the resolution, and high resolution cannot be achieved under a large exposure field of view.

Contents of the invention

The object of the present invention is to provide a projection objective lens with a large field of view and a photolithography machine, so as to achieve high resolution while expanding the exposure field of view.

In order to achieve the above object, the present invention provides a large field of view projection objective lens, comprising: comprising a first lens group, a second lens group, a third lens group and a fourth lens group arranged sequentially along the optical axis from the object side, so The focal length of the first lens group, the focal length of the second lens group, the focal length of the third lens group and the focal length of the fourth lens group satisfy the following relationship:

1.06<|f ₁ /f ₂ |<1.26;

1.76<|f ₂ /f ₃ |<1.90;

1.80<|f ₃ /f ₄ |<2.00;

3.85<|f ₁ /f ₄ |<4.25;

Wherein, f1 represents the focal length of the _first lens, f2 represents the focal length of the _second lens, _f3 represents the focal length of the third lens, and _f4 represents the focal length of the fourth lens.

Optionally, in the large field of view projection objective, the first lens group, the second lens group, the third lens group and the fourth lens group all have positive refractive power; The first lens group, the second lens group, the third lens group, and the fourth lens group all include aspheric lenses, each of which has an aspheric surface, and the first lens group , the sum of the numbers of the aspheric lenses in the second lens group, the third lens group and the fourth lens group is less than or equal to 11.

Optionally, in the large field of view projection objective, the first lens group includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence along the optical axis, the first lens and The second lens is an aspherical lens, and the surfaces of the first lens and the second lens near the object side are aspheric surfaces.

Optionally, in the large field of view projection objective, the first lens and the second lens both have negative refractive power, and the third lens and the fourth lens both have positive refractive power, Wherein, the first lens is a biconcave negative lens, the second lens is a meniscus negative lens, the third lens is a plano-convex positive lens, and the fourth lens is a biconvex positive lens.

Optionally, in the large field of view projection objective lens, the concave surface of the second lens faces the object side, and the concave surface of the second lens is an aspherical surface.

Optionally, in the large field of view projection objective, the second lens group includes:

The first sub-lens group includes at least two aspheric lenses, and the surfaces of all the aspheric lenses near the image side are aspheric surfaces;

The second sub-lens group includes at least three aspherical lenses, and the surfaces of all the aspheric lenses near the object side are aspheric surfaces; wherein, the first sub-lens group is larger than the second sub-lens group close to the object.

Optionally, in the large field of view projection objective, the first sub-lens group includes a fifth lens, a sixth lens, and a seventh lens arranged in sequence along the optical axis, and the sixth lens and the first lens The seven lenses are all aspheric lenses, and the surfaces of the sixth lens and the seventh lens near the image side are aspheric surfaces;

The second sub-lens group includes an eighth lens, a ninth lens, a tenth lens and an eleventh lens arranged in sequence along the optical axis, and the eighth lens, the ninth lens and the tenth lens are all An aspheric lens, and the surfaces of the eighth lens, the ninth lens, and the tenth lens near the object side are all aspheric surfaces.

Optionally, in the large field of view projection objective lens, the fifth lens, the sixth lens, the tenth lens and the eleventh lens all have positive refractive power, and the seventh lens, Both the eighth lens and the ninth lens have negative refractive power, wherein both the fifth lens and the eleventh lens are biconvex positive lenses; the sixth lens and the tenth lens The lenses are all meniscus positive lenses; the seventh lens, the eighth lens and the ninth lens are all biconcave negative lenses.

Optionally, in the large field of view projection objective lens, the concave surface of the sixth lens faces the image side, and the concave surface of the sixth lens is an aspheric surface; the concave surface of the tenth lens faces the image side; The object side, and the concave surface of the tenth lens is an aspherical surface.

Optionally, in the large-field-of-view projection objective, the third lens group includes a twelfth lens, a thirteenth lens, and a fourteenth lens arranged in sequence along the optical axis, and the thirteenth lens is An aspherical lens, and the surface of the thirteenth lens near the image side is an aspheric surface.

Optionally, in the large field of view projection objective, both the twelfth lens and the fourteenth lens have positive refractive power, and the thirteenth lens has negative refractive power, wherein the Both the twelfth lens and the fourteenth lens are biconvex positive lenses, and the thirteenth lens is a biconcave negative lens.

Optionally, in the large field of view projection objective, the fourth lens group includes a fifteenth lens, a sixteenth lens, a seventeenth lens and an eighteenth lens arranged in sequence along the optical axis, the The fifteenth lens, the sixteenth lens and the seventeenth lens are all aspherical lenses, and the surfaces of the fifteenth lens and the sixteenth lens near the image side are aspheric surfaces , the surface of the seventeenth lens near the object side is an aspheric surface.

Optionally, in the large-field-of-view projection objective, the fifteenth lens, the sixteenth lens, and the eighteenth lens all have positive refractive power, and the seventeenth lens has negative optical power. focal power, wherein, the fifteenth lens, the sixteenth lens and the eighteenth lens are all positive meniscus lenses, and the seventeenth lens is a biconcave negative lens.

Optionally, in the large field of view projection objective lens, the concave surface of the fifteenth lens and the concave surface of the sixteenth lens both face the image side, and the concave surface of the fifteenth lens and the concave surface of the sixteenth lens The concave surfaces of the sixteenth lens are all aspheric surfaces.

Optionally, in the large field of view projection objective lens, the large field of view projection objective lens further includes a stop, and the stop is arranged between the second lens group and the third lens group.

Optionally, in the large field of view projection objective lens, the large field of view projection objective lens further includes an object parallel flat plate and an image parallel flat plate, and the object parallel flat plate is arranged on the optical axis close to the object. On the side of the image side, the image side parallel plate is arranged on the side of the optical axis close to the image side.

Optionally, in the large-field projection objective, the effective focal length and conjugate distance of the large-field projection satisfy the following relationship:

0.95<|EFL/TT|<1.15;

Wherein, EFL represents the effective focal length of the large-field projection objective lens, and TT represents the conjugate distance of the large-field projection objective lens.

Optionally, in the large field of view projection objective lens, the materials of the lenses in the first lens group, the second lens group, the third lens group and the fourth lens group are all fused quartz.

Optionally, in the large-field-of-view projection objective, the object-side working distance of the large-field-of-view projection lens is greater than 32 mm, and the image-side working distance is greater than 12 mm.

Optionally, in the large field of view projection objective lens, the object space telecentricity of the large field of view projection lens is less than 6 mrad, and the image space telecentricity is less than 9 mrad.

Based on the same inventive concept, the present invention also provides a lithography machine, which includes the above-mentioned large field of view projection objective lens.

In the large field of view projection objective lens and lithography machine provided by the present invention, the large field of view projection objective lens includes a first lens group, a second lens group, a third lens group and a fourth lens arranged in sequence along the optical axis from the object side Group. Only four lens groups are used in the large-field-of-view projection objective lens, which can make the optical structure more compact, reduce the cost, and increase the transmittance of the projection objective lens system, thereby improving the exposure efficiency. In addition, the focal length f ₁ of the first lens group, the focal length f 2 of the second lens group, the focal length f ₃ of the third lens group, and the focal length f ₄ of the _fourth lens group satisfy 1.06<|f ₁ /f ₂ |<1.26;1.76<|f ₂ /f ₃ |<1.90;1.80<|f ₃ /f ₄ |<2.00;3.85<|f ₁ /f ₄ |<4.25, so configured, in the realization of expansion High resolution can be achieved while exposing the field of view.

Description of drawings

FIG. 1 is a schematic structural view of a large field of view projection objective lens according to Embodiment 1 of the present invention;

Fig. 2 is a schematic diagram of the modulation transfer function curves of each field of view of the large field of view projection objective lens according to Embodiment 1 of the present invention;

Fig. 3 is a schematic diagram of centroid distortion of the large field of view projection objective lens according to Embodiment 1 of the present invention;

4 is a schematic diagram of a telecentric curve of a large field of view projection objective lens according to Embodiment 1 of the present invention;

Fig. 5 is a schematic diagram of field curvature and astigmatism of the large field of view projection objective lens according to Embodiment 1 of the present invention;

FIG. 6 is a schematic structural view of a large field of view projection objective lens according to Embodiment 2 of the present invention;

7 is a schematic diagram of modulation transfer function curves of each field of view of the large field of view projection objective lens according to Embodiment 2 of the present invention;

Fig. 8 is a schematic diagram of centroid distortion of the large field of view projection objective lens according to Embodiment 2 of the present invention;

9 is a schematic diagram of a telecentric curve of a large field of view projection objective lens according to Embodiment 2 of the present invention;

Fig. 10 is a schematic diagram of field curvature and astigmatism of the large field of view projection objective lens according to Embodiment 2 of the present invention;

Wherein, the reference signs are explained as follows:

1-first lens; 2-second lens; 3-third lens; 4-fourth lens; 5-fifth lens; 6-sixth lens; 7-seventh lens; 8-eighth lens; 9- Ninth lens; 10-tenth lens; 11-eleventh lens; 12-twelfth lens; 13-thirteenth lens; 14-fourteenth lens; 15-fifteenth lens; 16-sixteenth lens Lens; 17-seventeenth lens; 18-eighteenth lens; 110-object parallel flat plate; 120-image parallel flat plate; G1-first lens group, G2-second lens group, G3-third lens group , G4-the fourth lens group.

detailed description

The present invention provides a projection objective lens with a large field of view and a photolithography machine. The projection objective lens with a large field of view only uses four sets of mirror groups, which can make the optical structure more compact, reduce the cost, and improve the transparency of the projection objective lens system. Over rate, thereby improving exposure efficiency. In addition, by adjusting the configuration of the focal length f ₁ of the first lens group, the focal length f ₂ of the second lens group, the focal length f ₃ of the third lens group, and the focal length f ₄ of the fourth lens group, while realizing the expansion of the exposure field of view High resolution can also be achieved.

The large field of view projection objective lens and photolithography machine proposed by the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description. It should be noted that all the drawings are in a very simplified form and use imprecise scales, and are only used to facilitate and clearly assist the purpose of illustrating the embodiments of the present invention.

[Example 1]

FIG. 1 is a schematic structural diagram of a projection objective lens with a large field of view provided by Embodiment 1 of the invention. As shown in FIG. 1 , this embodiment provides a projection objective lens with a large field of view, which is used to project an image from the object side onto the image side (Image). The large field of view projection objective lens includes a first lens group G1 , a second lens group G2 , a third lens group G3 and a fourth lens group G4 arranged in sequence along the optical axis from the object (Object). In this embodiment, only four sets of lens groups are used in the large field of view projection objective lens, which reduces the number of lenses in the objective lens compared with the prior art, makes the optical structure more compact, reduces the cost, and improves the objective lens. The transmittance of the system, thereby improving the exposure efficiency.

Preferably, the focal length of the first lens group G1, the focal length of the second lens group G2, the focal length of the third lens group G3 and the focal length of the fourth lens group G4 satisfy the following relationship:

1.06<|f1/f2|<1.26;

1.76<|f2/f3|<1.90;

1.80<|f3/f4|<2.00;

3.85<|f1/f4|<4.25;

Wherein, f1 represents the focal length of the _first lens group G1, f2 represents the focal length of the _second lens group G2, _f3 represents the focal length of the third lens group G3, and _f4 represents the fourth lens group The focal length of the G4. With such a configuration, high resolution can be realized while expanding the exposure field of view.

In addition, the effective focal length and conjugate distance (object image conjugate distance) of the large field of view projection objective lens satisfy the following relationship:

0.95<|EFL/TT|<1.15;

Wherein, EFL represents the effective focal length of the large-field projection objective lens, and TT represents the conjugate distance of the large-field projection objective lens.

In this embodiment, the first lens group G1 , the second lens group G2 , the third lens group G3 and the fourth lens group G4 all have positive refractive power. Among them, the focal power is equal to the difference between the convergence of the image beam and the object beam, which represents the ability of the optical system to deflect light. The greater the absolute value of the optical power, the stronger the ability to bend light, and the smaller the absolute value of the optical power, the weaker the ability to bend light. When the optical power is positive, the refraction of light is converging. Optical power can be applied to characterize a certain refraction surface of a lens (that is, a surface of the lens), can be applied to characterize a certain lens, and can also be used to characterize a system formed by multiple lenses (that is, a lens group).

The first lens group G1 , the second lens group G2 , the third lens group G3 and the fourth lens group G4 all include aspheric lenses, and the aspheric lenses are lenses with aspheric surfaces. Each of the aspheric lenses has an aspheric surface, and the other surface of the aspheric lens is spherical or flat. Because the processing and detection difficulty of an aspheric lens with only one aspheric surface is far lower than that of an aspheric lens with two aspheric surfaces, the aspheric lens is set to have one aspheric surface in this embodiment, which reduces the cost of the aspheric lens. manufacturing and measurement costs. In addition, the sum of the numbers of the aspheric lenses in the first lens group G1 , the second lens group G2 , the third lens group G3 and the fourth lens group G4 is less than or equal to 11. That is, the total number of aspheric lenses used in the four groups of lenses of the large field of view projection objective lens is less than or equal to 11, and fewer aspheric lenses are used, which reduces the cost of the projection objective lens while ensuring the imaging quality.

Furthermore, compared with spherical lenses, aspheric lenses have better phase elimination effects. In this embodiment, each lens group in the projection objective lens with large field of view includes an aspheric lens, so that each lens group in the projection objective lens with large field of view has a better phase elimination effect, thereby improving the performance of the large field of view. The image quality of the projection objective.

Exemplarily, the first lens group G1 includes four lenses arranged in sequence along the optical axis direction, namely the first lens 1, the second lens 2, the third lens 3 and the fourth lens 4, the first lens 1 and the second lens 2 are aspheric lenses, and the surfaces of the first lens 1 and the second lens 2 near the object side are aspheric surfaces. Wherein, both the first lens 1 and the second lens 2 have negative refractive power. The first lens 1 may be a biconcave negative lens for diverging light beams. The second lens 2 may be a negative meniscus lens, whose mirror surface has a small radius of curvature, has the function of eliminating chromatic aberration, and is beneficial to the correction of aberration.

In a preferred solution, the concave surface of the second lens 2 faces the object side, and the concave surface of the second lens 2 is aspherical. Since the detection accuracy of the concave surface in the lens is high, and the detection accuracy of the convex surface in the lens is low, in the embodiment of the present invention, the aspheric surface is arranged on the concave surface of the aspheric lens, which improves the detection accuracy of the aspheric surface, thereby improving This ensures the product reliability of the large field of view projection objective lens.

Both the third lens 3 and the fourth lens 4 have positive refractive power. Wherein, the third lens 3 may be a plano-convex positive lens for converging light beams. The fourth lens 4 may be a biconvex positive lens for converging light beams.

The second lens group G2 includes a first sub-lens group and a second sub-lens group, and the first sub-lens group is closer to the object side than the second sub-lens group. Wherein, the first sub-lens group includes at least two aspheric lenses, and the surfaces of all the aspheric lenses near the image side are aspheric surfaces.

Specifically, the first sub-lens group includes a fifth lens 5 , a sixth lens 6 and a seventh lens 7 arranged in sequence along the optical axis. The fifth lens 5 has a positive refractive power, and is a biconvex positive lens for converging light beams. The sixth lens 6 has positive refractive power and is an aspherical lens, and the surface of the sixth lens 6 near the image side is an aspheric surface. Wherein, the sixth lens 6 is a positive meniscus lens, which has the function of eliminating chromatic aberration. Further, the concave surface of the sixth lens 6 faces the image side, and the concave surface of the sixth lens 6 is an aspherical surface.

The seventh lens 7 has negative refractive power and is an aspheric lens, and the surface of the seventh lens 7 near the image side is an aspheric surface. Wherein, the seventh lens 7 is a biconcave negative lens for diverging light beams.

The second sub-lens group includes at least three aspheric lenses, and the surfaces of all the aspheric lenses near the object side are aspheric surfaces. Specifically, the second sub-lens group includes an eighth lens 8 , a ninth lens 9 , a tenth lens 10 and an eleventh lens 11 arranged in sequence along the optical axis.

The eighth lens 8, the ninth lens 9 and the tenth lens 10 are all aspheric lenses, and the eighth lens 8, the ninth lens 9 and the tenth lens 10 are close to the The surfaces on the object side are all aspheric surfaces. Wherein, both the eighth lens 8 and the ninth lens 9 have negative refractive power, and both the eighth lens 8 and the ninth lens 9 may be biconcave negative lenses for diverging light beams.

The tenth lens 10 has positive refractive power and is a positive meniscus lens for converging light beams. In addition, the concave surface of the tenth lens 10 faces the object side, and the concave surface of the tenth lens 10 is an aspherical surface.

The eleventh lens 11 has a positive refractive power and is a biconvex positive lens for converging light beams. That is, the fifth lens 5, the sixth lens 6, the seventh lens 7, the ninth lens 9, the tenth lens 10 and the tenth lens in the second lens group G2 A lens 11 is symmetrically distributed on both sides of the eighth lens 8 .

In addition, the large field of view lens objective lens is an optical system structure with a waist. The waist represents the position where the aperture of the lens shrinks, so that the effective aperture of the light spot passing through the corresponding lens is reduced. Specifically, the waist of the large field of view projection objective lens is located in the second lens group G2, because the second lens group G2 includes the seventh lens 7, the eighth lens 8 and the ninth lens with negative power Lenses 9, these lenses with negative refractive power appear in the area of relatively small spot diameter in the optical path of the projection objective lens, so that lenses with relatively small effective light aperture can be used in the second lens group G2, and it is beneficial to aberration Correction of the middle curvature. In addition, the apertures of the aspheric lenses (ie, the seventh lens 7, the eighth lens 8, and the ninth lens 9) in the second lens group G2 can be reduced, thereby reducing the processing difficulty and detection difficulty of the aspheric lenses, Thereby reducing the processing cost. Wherein, the aperture of the lens refers to the effective aperture of the lens.

Further, the maximum effective radius of at least one lens in the second lens group G2 does not exceed 170 mm, for example, the eighth lens 8, since its maximum effective radius does not exceed 170 mm, a blank material with a diameter of 340 mm can be used Manufacturing, the rough material of this size is easier to obtain and the cost is controlled.

In this embodiment, the third lens group G3 includes a twelfth lens 12, a thirteenth lens 13, and a fourteenth lens 14 arranged in sequence along the optical axis, the thirteenth lens 13 is an aspheric lens, and The surface of the thirteenth lens 13 near the image side is an aspherical surface. Both the twelfth lens 12 and the fourteenth lens 14 have positive refractive power, and the thirteenth lens 13 has negative refractive power. Wherein, the twelfth lens 12 and the fourteenth lens 14 are biconvex positive lenses for converging light beams. The thirteenth lens 13 is a biconcave negative lens for diverging light beams.

The fourth lens group G4 includes a fifteenth lens 15, a sixteenth lens 16, a seventeenth lens 17, and an eighteenth lens 18 arranged in sequence along the optical axis, the fifteenth lens 15, the tenth lens The sixth lens 16 and the seventeenth lens 17 are all aspheric lenses, and the surfaces of the fifteenth lens 15 and the sixteenth lens 16 near the image side are aspheric surfaces, and the first The surface of the seventeen lens 17 near the object side is an aspheric surface.

The fifteenth lens 15 , the sixteenth lens 16 and the eighteenth lens 18 all have positive refractive power, and the seventeenth lens 17 has negative refractive power. Wherein, the fifteenth lens 15 and the sixteenth lens 16 are positive meniscus lenses, which have the effect of eliminating chromatic aberration. Further, the concave surface of the fifteenth lens 15 and the concave surface of the sixteenth lens 16 are both facing the image side, and the concave surface of the fifteenth lens 15 and the concave surface of the sixteenth lens 16 are both is an aspheric surface. The seventeenth lens 17 has a negative power, and is a biconcave negative lens for diverging light beams. The eighteenth lens 18 has a positive refractive power, is a positive meniscus lens, has the effect of eliminating chromatic aberration, and can realize corrections such as curvature of field or advanced aberrations.

Continue to refer to shown in Fig. 1, in the present embodiment, described large field of view projection objective lens also comprises object parallel plate 110 and image space parallel plate 120, and described object parallel plate 110 is arranged on described optical axis and is close to described object. side of the image side (that is, the side of the first lens group G1 close to the object side), and the image side parallel plate 120 is arranged on the side of the optical axis close to the image side (that is, the side of the fourth lens group G1 G4 is close to the side of the image square). The object-space parallel plate 110 and the image-space parallel plate 120 have no optical power and are used to protect components inside the objective lens. For example, the first lens group G1 , the second lens group G2 , the third lens group G3 and the fourth lens group G4 can be protected from external pollution.

The large field of view projection objective lens further includes a stop (STOP), and the stop is arranged between the second lens group G2 and the third lens group G3. Wherein, the diaphragm is an aperture diaphragm. The effective light aperture of the large field of view projection objective lens can be adjusted by adjusting the size of the aperture, that is, the numerical aperture of the large field of view projection objective lens can be adjusted by adjusting the aperture to adapt to different application scenarios. Optionally, the maximum image-side numerical aperture of the large-field projection objective provided in this embodiment can be 0.57, and the numerical aperture of the large-field projection objective can be within 0-0.57 by adjusting the size of the diaphragm (STOP) Continuously adjustable.

Continue to refer to shown in Fig. 1, described large field of view projection objective lens has double telecentric structure of object side and image side, and the chief ray of each field of view of object side is approximately parallel to the optical axis incident on object side parallel plate 110 near the surface of object side (that is Object space parallel to the front surface of the plate). On the object side, the chief ray of each field of view on the object plane is incident on the object parallel flat plate 110 parallel to the optical axis, and the angle between the chief ray and the optical axis is less than 6 mrad. On the image side, the chief ray of each field of view exits parallel to the optical axis, and is imaged on the image plane, with an included angle greater than 7 mrad with the optical axis. Furthermore, the chief rays of each field of view on the image side exit approximately parallel to the optical axis and converge on the image plane, which can improve the overlay accuracy. In addition, the object-side working distance of the large-field-of-view projection lens is greater than 32 mm, and the image-side working distance is greater than 12 mm.

Table 1 provides the specific parameters of the projection objective lens of the first embodiment, the positive value of the radius (R) represents that the center of curvature of the lens is on the side close to the image side; the negative value of the radius (R) represents The center of curvature of the lens is on the side close to the object side; where "OBJ" in the serial number represents the object plane, "P1" represents the object parallel flat plate, "STOP" represents the diaphragm, and "P2" represents the image parallel parallel plate , "IMA" represents the image plane, "a" represents the surface of the lens near the object side; "b" represents the surface of the lens near the image side, taking "18a" as an example, which represents the eighteenth lens 18 close to the object The surface on the square side; the radius of "1.00E+18" means that the lens surface corresponding to the radius is a plane; "full aperture" means the maximum light aperture of the lens surface; "thickness" means the air gap or the thickness of the optical element.

Table 1 Parameters of large field of view projection objective lens

In this embodiment, the materials used for the lenses in the first lens group G1, the second lens group G2, the third lens group G3 and the fourth lens group G4 may be fused silica, but not limited to Therefore, other materials with a refractive index of 1.45 can also be used. In addition, the material of the object-space parallel plate 110 and the image-space parallel plate 120 can also be fused silica. Since the refractive index of fused silica is 1.45 and the Abbe number is 67, this material is relatively stable and has high reliability and excellent performance. superior. The lens made of fused silica has the advantages of stable process and high product yield, good manufacturability and controllable cost.

In this embodiment, the expression of the aspheric surface of the aspheric lens is:

r表示x和y的对角线上的径向距离，x表示X方向的坐标值，y表示Y方向的坐标值，z表示表面Z方向的轴向矢高，X方向、Y方向和Z方向符合笛卡尔坐标系，k表示最佳拟合圆锥的圆锥系数，c表示最佳拟合球面的曲率(curv)，A、B、C、D、E、F、G、H和J均表示非球面系数(A为四阶常量系数，B为六阶常量系数，C为八阶常量系数，D为十阶常量系数，E为十二阶常量系数，F为十四阶常量系数，G为十六阶常量系数，H为十八阶常量系数，J为二十阶常量系数)。in,

r represents the radial distance on the diagonal of x and y, x represents the coordinate value in the X direction, y represents the coordinate value in the Y direction, z represents the axial sagittal height in the Z direction of the surface, and the X direction, the Y direction and the Z direction conform to Cartesian coordinate system, k represents the conic coefficient of the best-fit cone, c represents the curvature (curv) of the best-fit sphere, and A, B, C, D, E, F, G, H, and J represent aspheric surfaces Coefficient (A is the fourth-order constant coefficient, B is the sixth-order constant coefficient, C is the eighth-order constant coefficient, D is the tenth-order constant coefficient, E is the twelfth-order constant coefficient, F is the fourteenth-order constant coefficient, G is sixteen The order constant coefficient, H is the eighteenth order constant coefficient, J is the twenty order constant coefficient).

The specific design value of the aspheric surface of the aspheric lens in the projection objective lens of table 2 large field of view

In this embodiment, the total length of the large field of view projection objective lens is not more than 1300mm, and is suitable for the i-line ultraviolet spectral range, and the maximum spectral width can reach 5nm. Exemplarily, the reference wavelength can be 355nm, the spectral width can be 0.001nm or -0.001nm, the magnification can be -0.5, the maximum numerical aperture of the image can be 0.57, and the diameter of the image field (exposure field) is not less than 65.0mm, and the maximum height of the field of view can be 32.5mm.

Fig. 2 is the modulation transfer function curve schematic diagram of each field of view of the large field of view projection objective lens of embodiment one of the present invention, in Fig. 2, abscissa is spatial frequency (Spatial Frequency), and the unit is line pair/millimeter (lp/mm), The ordinate is the modulation degree (or contrast), and the modulation transfer function (Modulation Transfer Function, MTF) is a function of the spatial frequency (Spatial Frequency) as a variable, which reflects the ability of the optical system to transmit various frequency sinusoidal modulation degrees (Modulation) . As shown in FIG. 2 , the performance of the large field of view projection objective lens is close to the diffraction limit, and the performance in the entire field of view is very good.

Fig. 3 is the centroid distortion diagram of the large field of view projection objective lens according to Embodiment 1 of the present invention. In Fig. 3, the abscissa is the height of the field of view of the X object side (X Object Height), which represents the height of the field of view of the object side in the X direction , the unit of the abscissa is mm. The ordinate is the height of the Y object field of view (Y Object Height), indicating the height of the object field of view in the Y direction, and the unit of the ordinate is mm. It can be seen from Figure 3 that the distortion of each half-field point on the object side is basically 0, that is, the distortion of the large-field projection objective lens has been corrected to 0.

Fig. 4 is a telecentric curve diagram of the large-field-of-view projection objective lens according to Embodiment 1 of the present invention, wherein the abscissa in Fig. 4 is the height of the field of view at the object side (Object Height), and the ordinate is the telecentricity (Telecentricity). As can be seen from curve a in Fig. 4, the object space telecentricity (TE object) of described large field of view projection objective lens is less than 6mrad, as can be seen from curve b in Fig. 4, the image of described large field of view projection objective lens Fang Yuanxin (TE image) is less than 7mrad. Fig. 5 is a schematic diagram of field curvature and astigmatism of the large-field projection objective lens according to Embodiment 1 of the present invention. It can be seen from Fig. 5 that the field curvature and astigmatism of the large-field projection objective lens have been corrected to a smaller range .

Based on the same inventive concept, this embodiment also provides a lithography machine, the lithography machine includes the above-mentioned large field of view projection objective lens, which will not be repeated here.

[Example 2]

FIG. 6 is a structural diagram of a projection objective lens with a large field of view provided by Embodiment 2 of the present invention. As shown in FIG. 6 , this embodiment provides a large field of view projection objective lens, which is used to project an image of the object space on the image space. A lens group G1, a second lens group G2, a third lens group G3 and a fourth lens group G4. In this embodiment, the focal length of the first lens group G1, the focal length of the second lens group G2, the focal length of the third lens group G3 and the focal length of the fourth lens group G4 satisfy the following relationship: 1.06 <|f ₁ /f ₂ |<1.26;1.76<|f ₂ /f ₃ |<1.90;1.80<|f ₃ /f ₄ |<2.00;3.85<|f ₁ /f ₄ |<4.25; ₁ represents the focal length of the first lens group, f2 represents the focal length of the _second lens group, _f3 represents the focal length of the third lens group, and _f4 represents the focal length of the fourth lens group.

The structure of the large field of view projection objective lens in this embodiment is the same as the structure of the large field of view projection objective lens in Embodiment 1, which will not be repeated here. The difference between this embodiment and Embodiment 1 lies in that the operating conditions, exposure field size, and image-side numerical aperture of the large-field projection objective lens of this embodiment are different from the large-field projection objective lens of Embodiment 1. Specifically, in this embodiment, the large field of view projection objective lens can be used in the i-line ultraviolet spectral range, the wavelength is 355nm, the spectral width is 0.001nm or -0.001nm, the magnification can be -0.5, and the maximum numerical aperture of the image side It can be 0.45, and the image square field of view (exposure field of view) can be 54.0mmx34.0mm to improve exposure efficiency.

Fig. 7 is the modulation transfer function curve schematic diagram of each field of view of the large field of view projection objective lens of embodiment two, and among Fig. 7, abscissa is spatial frequency (Spatial Frequency), and unit is line pair/millimeter (lp/mm), and ordinate The modulation degree (or contrast), the modulation transfer function (Modulation Transfer Function, MTF) is a function of the spatial frequency (Spatial Frequency) as a variable, reflecting the ability of the optical system to transfer various frequency sinusoidal modulation degrees (Modulation). It can be seen from FIG. 7 that the performance of the large field of view projection objective lens is close to the diffraction limit, and the performance in the entire field of view is very good. Fig. 8 is a centroid distortion diagram of the large field of view projection objective lens according to Embodiment 2 of the present invention, wherein the abscissa is the height of the X object field of view (XObject Height), which represents the height of the object field of view in the X direction, and the abscissa The unit of the ordinate is mm, and the ordinate is the height of the field of view of the Y object (Y Object Height), indicating the height of the field of view of the object in the Y direction. The unit of the ordinate is mm. It can be seen from Figure 8 that each object The distortion of the half-field point is basically 0, indicating that the distortion of the objective lens has been corrected to 0. Fig. 9 is a schematic diagram of the telecentricity curve of the large field of view projection objective lens according to the second embodiment of the present invention. As can be seen from the curve c in Fig. 9, the object space telecentricity (TE object) of the large field of view projection objective lens is less than 6mrad, as shown in Fig. It can be seen from the curve d in 9 that the image telecentricity (TEimage) of the large field of view projection objective lens is less than 7mrad. FIG. 10 is a schematic diagram of field curvature and astigmatism of the large-field projection objective lens in Embodiment 2. It can be seen from FIG. 10 that the field curvature and astigmatism of the large-field projection objective lens have been corrected to a smaller range.

Based on the same inventive concept, an embodiment of the present invention further provides a lithography machine, the lithography machine includes the above-mentioned large field of view projection objective lens, which will not be repeated here.

To sum up, in the large field of view projection objective lens and the lithography machine provided by the embodiment of the present invention, the large field of view projection objective lens includes a first lens group, a second lens group, a third lens group arranged in sequence along the optical axis from the object side lens group and the fourth lens group. The large-field-of-view projection objective lens only uses four sets of mirror groups, which can make the optical structure more compact, reduce the cost, and improve the transmittance of the projection objective lens system, thereby improving the exposure efficiency. In addition, the focal length f ₁ of the first lens group, the focal length f 2 of the second lens group, the focal length f ₃ of the third lens group, and the focal length f ₄ of the _fourth lens group satisfy 1.06<|f ₁ /f ₂ |<1.26;1.76<|f ₂ /f ₃ |<1.90;1.80<|f ₃ /f ₄ |<2.00;3.85<|f ₁ /f ₄ |<4.25, so configured, in the realization of expansion High resolution can be achieved while exposing the field of view.

The above description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the present invention. Any changes and modifications made by those of ordinary skill in the field of the present invention based on the above disclosures shall fall within the protection scope of the claims.

Claims (21)

1. A large field of view projection objective lens is used to project the image of the object side on the image side, it is characterized in that, comprising the first lens group, the second lens group, the third lens group arranged in sequence along the optical axis from the object side The lens group and the fourth lens group, the focal length of the first lens group, the focal length of the second lens group, the focal length of the third lens group and the focal length of the fourth lens group satisfy the following relationship: 1.06<|f ₁ /f ₂ |<1.26; 1.76<|f ₂ /f ₃ |<1.90; 1.80<|f ₃ /f ₄ |<2.00; 3.85<|f ₁ /f ₄ |<4.25; Wherein, f1 represents the focal length of the _first lens group, f2 represents the focal length of the _second lens group, _f3 represents the focal length of the third lens group, and _f4 represents the focal length of the fourth lens group. 2. large field of view projection objective lens as claimed in claim 1, is characterized in that, described first lens group, described second lens group, described 3rd lens group and described 4th lens group all have positive optical focus degree; the first lens group, the second lens group, the third lens group and the fourth lens group all include aspheric lenses, each of which has an aspheric surface, the The sum of the numbers of the aspheric lenses in the first lens group, the second lens group, the third lens group and the fourth lens group is less than or equal to 11. 3. large field of view projection objective lens as claimed in claim 2, is characterized in that, described first lens group comprises first lens, second lens, the 3rd lens and the 4th lens that arrange in sequence along optical axis, described The first lens and the second lens are aspherical lenses, and the surfaces of the first lens and the second lens near the object side are aspheric surfaces. 4. large field of view projection objective lens as claimed in claim 3, is characterized in that, described first lens and described second lens all have negative refractive power, and described 3rd lens and described 4th lens all have Positive refractive power, wherein, the first lens is a biconcave negative lens, the second lens is a meniscus negative lens, the third lens is a plano-convex positive lens, and the fourth lens is a biconvex Positive lens. 5 . The large field of view projection objective lens according to claim 4 , wherein the concave surface of the second lens faces the object side, and the concave surface of the second lens is an aspherical surface. 6. The large field of view projection objective lens as claimed in claim 2, wherein the second lens group comprises: The first sub-lens group includes at least two aspheric lenses, and the surfaces of all the aspheric lenses near the image side are aspheric surfaces; The second sub-lens group includes at least three aspheric lenses, and the surfaces of all the aspheric lenses near the object side are aspheric surfaces; Wherein, the first sub-lens group is closer to the object side than the second sub-lens group. 7. The projection objective lens with large field of view as claimed in claim 6, wherein the first sub-lens group comprises the fifth lens, the sixth lens and the seventh lens arranged in sequence along the optical axis, and the sixth lens and the seventh lens are both aspherical lenses, and the surfaces of the sixth lens and the seventh lens near the image side are aspheric surfaces; The second sub-lens group includes an eighth lens, a ninth lens, a tenth lens and an eleventh lens arranged in sequence along the optical axis, and the eighth lens, the ninth lens and the tenth lens are all An aspheric lens, and the surfaces of the eighth lens, the ninth lens, and the tenth lens near the object side are all aspheric surfaces. 8. The large field of view projection objective lens as claimed in claim 7, wherein the fifth lens, the sixth lens, the tenth lens and the eleventh lens all have positive refractive power, so The seventh lens, the eighth lens and the ninth lens all have negative refractive power, wherein the fifth lens and the eleventh lens are biconvex positive lenses; the sixth lens and the tenth lens are meniscus positive lenses; the seventh lens, the eighth lens and the ninth lens are all biconcave negative lenses. 9. The projection objective lens with large field of view as claimed in claim 8, wherein the concave surface of the sixth lens is towards the image side, and the concave surface of the sixth lens is an aspherical surface; the tenth lens The concave surface of the tenth lens is facing the object side, and the concave surface of the tenth lens is an aspheric surface. 10. The projection objective lens with large field of view as claimed in claim 2, wherein the third lens group comprises a twelfth lens, a thirteenth lens and a fourteenth lens arranged in sequence along the optical axis, and the third lens group The thirteenth lens is an aspherical lens, and the surface of the thirteenth lens near the image side is an aspheric surface. 11. The projection objective lens with large field of view as claimed in claim 10, wherein the twelfth lens and the fourteenth lens all have positive refractive power, and the thirteenth lens has negative refractive power, Wherein, the twelfth lens and the fourteenth lens are biconvex positive lenses, and the thirteenth lens is a biconcave negative lens. 12. The projection objective lens with large field of view as claimed in claim 2, wherein the fourth lens group comprises the fifteenth lens, the sixteenth lens, the seventeenth lens and the eighteenth lens arranged in sequence along the optical axis lens, the fifteenth lens, the sixteenth lens and the seventeenth lens are all aspherical lenses, and the surfaces of the fifteenth lens and the sixteenth lens are close to the image side is an aspheric surface, and the surface of the seventeenth lens near the object side is an aspheric surface. 13. The large field of view projection objective lens as claimed in claim 12, wherein the fifteenth lens, the sixteenth lens and the eighteenth lens all have positive refractive power, and the seventeenth lens The lenses have negative refractive power, wherein the fifteenth lens, the sixteenth lens and the eighteenth lens are all positive meniscus lenses, and the seventeenth lens is a biconcave negative lens. 14. The large field of view projection objective lens according to claim 13, wherein the concave surface of the fifteenth lens and the concave surface of the sixteenth lens are all towards the image side, and the fifteenth lens The concave surface of the lens and the concave surface of the sixteenth lens are aspherical surfaces. 15. The large field of view projection objective lens according to any one of claims 1 to 14, characterized in that, the large field of view projection objective lens also comprises an aperture, and the aperture is arranged between the second lens group and Between the third lens group. 16. The large field of view projection objective lens according to any one of claims 1 to 14, wherein the large field of view projection objective lens also comprises an object parallel flat plate and an image parallel flat plate, and the object parallel flat plate It is arranged on the side of the optical axis close to the object side, and the image side parallel plate is set on the side of the optical axis close to the image side. 17. The large field of view projection objective as claimed in any one of claims 1 to 14, wherein the effective focal length and the conjugate distance of the large field of view projection satisfy the following relationship: 0.95<|EFL/TT|<1.15; Wherein, EFL represents the effective focal length of the large-field projection objective lens, and TT represents the conjugate distance of the large-field projection objective lens. 18. The large field of view projection objective lens according to any one of claims 1 to 14, wherein the first lens group, the second lens group, the third lens group and the fourth lens group The materials of the lenses in the lens group are all fused silica. 19. The large field of view projection objective according to any one of claims 1 to 14, characterized in that, the object side working distance of the large field of view projection lens is greater than 32 mm, and the image side working distance is greater than 12 mm. 20. The large-field projection objective lens according to any one of claims 1 to 14, wherein the object-side telecentricity of the large-field projection objective lens is less than 6 mrad, and the image-side telecentricity is less than 7 mrad. 21. A lithography machine, characterized in that the lithography machine comprises the large field of view projection objective lens according to any one of claims 1-20.

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