TWI705279B - Projection objective lens and exposure system - Google Patents

Abstract

The invention discloses a projection objective lens and an exposure system. The aforementioned projection objective lens includes a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, an aperture stop, and a The fourth lens group with positive refractive power, the fifth lens group with negative refractive power, and the sixth lens group with positive refractive power; the first lens group and the sixth lens group are symmetrical based on the aperture stop, the second lens group and The fifth lens group is based on the symmetry of the aperture stop, the third lens group and the fourth lens group are based on the aperture stop symmetry, and satisfy the following relationship: -0.7<f1/f2<-0.3, -1.1<f2/f3<-0.6 , -1.1<f5/f4<-0.6, -0.7<f6/f5<-0.3, where f1, f2, f3, f4, f5, and f6 are the first lens group, the second lens group, and the third lens group, respectively , The focal lengths of the fourth lens group, the fifth lens group, and the sixth lens group. The technical means provided by the embodiments of the present invention improve the compatibility of the projection objective lens and improve the modularization level of the exposure system.

Description

Projection objective lens and exposure system

The embodiment of the present invention relates to a projection objective optical system, for example, to a projection objective lens and an exposure system.

Optical lithography is a technology that uses light to project and copy mask patterns. The device using optical lithography technology is an exposure system. With the help of the projection exposure system, patterns with different mask patterns are imaged onto a substrate, such as silicon or LCD panels are used to manufacture a series of structures such as integrated circuits, thin-film magnetic heads, liquid crystal display panels, or micro-electromechanical (MEMS).

The light source of the exposure system includes mercury lamp light source and LED light source. LED light source is divided into i-line light source and igh three-line light source. In addition, the basic exposure methods of the exposure system include stepping and scanning. Among them, the mercury lamp light source and the LED light source have different spectral widths, the i-line light source and the igh three-line light source have different wavelength ranges, and the size of the object field of step exposure and scanning exposure are different. The exposure system in related technologies usually only targets The projection objective is designed for a certain light source or exposure method, which makes the projection objective incompatible with the above three different parameters, resulting in poor compatibility of the exposure system.

The invention provides a projection objective lens and an exposure system to improve the compatibility of the projection objective lens.

In a first aspect, an embodiment of the present invention provides a projection objective lens, which is characterized by comprising a first lens group with positive refractive power, a second lens group with negative refractive power, and a The third lens group with positive refractive power, the aperture stop, the fourth lens group with positive refractive power, the fifth lens group with negative refractive power, and the sixth lens group with positive refractive power; the aforementioned first lens group and The aforementioned sixth lens group is based on the aforementioned aperture diaphragm symmetry, the aforementioned second lens group and the aforementioned fifth lens group are based on the aforementioned aperture diaphragm symmetry, and the aforementioned third lens group and the aforementioned fourth lens group are based on the aforementioned aperture diaphragm symmetry;

The first lens group is used to correct spherical aberration, astigmatism and field curvature related to the field distribution, the second lens group is used to match and compensate the aberrations generated by the first lens group and the third lens group, the third lens The group is used to correct chromatic aberration, constant term spherical aberration and astigmatism. The fourth lens group is used to compensate for the coma and distortion produced by the third lens group. The fifth lens group is used to compensate for the coma produced by the second lens group. Aberration and distortion, the sixth lens group is used to compensate coma and distortion generated by the first lens group;

The aforementioned projection objective satisfies the following relationship:

-0.7<f1/f2<-0.3

-1.1<f2/f3<-0.6

-1.1<f5/f4<-0.6

-0.7<f6/f5<-0.3

Among them, f1 is the focal length of the first lens group, f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, f4 is the focal length of the fourth lens group, f5 is the focal length of the fifth lens group, and f6 is the focal length of the fifth lens group. The focal length of the six lens group.

In a second aspect, an embodiment of the present invention further provides an exposure system, which is characterized in that it includes the projection objective described in the first aspect.

The projection objective provided by the embodiment of the present invention includes a first lens group with positive refractive power, a second lens group with negative refractive power, and a third lens group with positive refractive power, which are sequentially arranged from the object plane along the optical axis. An aperture stop, a fourth lens group with positive refractive power, a fifth lens group with negative refractive power, and a sixth lens group with positive refractive power. The first lens group and the sixth lens group are symmetrical based on the aperture stop, The second lens group and the fifth lens group are based on the symmetry of the aperture stop, and the third lens group and the fourth lens group are based on the symmetry of the aperture stop. The projection objective satisfies the following relationship: -0.7<f1/f2<-0.3, -1.1< f2/f3<-0.6, -1.1<f5/f4<-0.6, -0.7<f6/f5<-0.3, where f1 is the focal length of the first lens group, f2 is the focal length of the second lens group, and f3 is the The focal length of the three lens group, f4 is the focal length of the fourth lens group, f5 is the focal length of the fifth lens group, and f6 is the focal length of the sixth lens group. The diameter of the object field of view and the applicable wavelength range of the projection objective lens with the above-mentioned structure are relatively large, so that the projection objective lens can be compatible with step exposure and scanning mode exposure, compatible with ghi three-line wavelength and i single-line wavelength, and compatible with mercury light sources and The LED light source significantly improves the compatibility of the projection objective and improves the modularization level of the exposure system.

1‧‧‧Light source assembly

2‧‧‧Quartz Rod

3‧‧‧Relay Group

4‧‧‧Mask

5‧‧‧Projection Objective

6‧‧‧Silicon

10‧‧‧Object plane

30‧‧‧Aperture diaphragm

110‧‧‧First lens group

111‧‧‧First lens

112‧‧‧Second lens

113‧‧‧third lens

114‧‧‧Fourth lens

120‧‧‧Second lens group

121‧‧‧Fifth lens

122‧‧‧Sixth lens

130‧‧‧Third lens group

131‧‧‧Seventh lens

132‧‧‧Eighth lens

133‧‧‧Ninth lens

134‧‧‧Tenth lens

140‧‧‧Fourth lens group

150‧‧‧Fifth lens group

160‧‧‧Sixth lens group

The following is a brief introduction to the drawings that must be used in describing the embodiments. Obviously, The diagrams introduced are only the diagrams of a part of the embodiments to be described in the present invention, not all of the diagrams. For those with ordinary knowledge in the technical field, they can also be based on these diagrams without creative work. Formula to get other schemas.

[Figure 1] is a schematic structural diagram of a projection objective provided by an embodiment of the present invention.

[Fig. 2] is a diagram of aberration of light rays of a projection objective provided by an embodiment of the present invention.

Fig. 3 is a vertical axis chromatic aberration diagram of a projection objective provided by an embodiment of the present invention.

[Figure 4] is a telecentric curve of a projection objective provided by an embodiment of the present invention.

[Fig. 5] is a diagram of ray aberration of another projection objective provided by an embodiment of the present invention.

Fig. 6 is a vertical axis chromatic aberration diagram of another projection objective provided by an embodiment of the present invention.

Fig. 7 is a telecentric curve of another projection objective provided by an embodiment of the present invention.

[Fig. 8] is a diagram of ray aberration of another projection objective provided by an embodiment of the present invention.

Fig. 9 is a vertical axis chromatic aberration diagram of another projection objective provided by an embodiment of the present invention.

[Figure 10] is a telecentric curve of another projection objective provided by an embodiment of the present invention.

[Fig. 11] is a diagram of ray aberration of another projection objective provided by an embodiment of the present invention.

Fig. 12 is a vertical axis chromatic aberration diagram of yet another projection objective provided by an embodiment of the present invention.

[Figure 13] is a telecentric curve of another projection objective provided by an embodiment of the present invention.

[Figure 14] is a schematic structural diagram of an exposure system provided by an embodiment of the present invention.

The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described here are only used to explain the present invention, not to explain the present invention. The limit. In addition, it should be noted that, for ease of description, the drawings only show part of the content related to the present invention, but not all of the content. Before discussing the exemplary embodiments in more detail, it should be mentioned that some of the exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowchart describes various operations (or steps) as sequential processing, many of the operations can be implemented in parallel, concurrently, or simultaneously. In addition, the order of various operations can be rearranged. The aforementioned processing can be terminated when its operation is completed, but it can also have additional steps not included in the diagram. The aforementioned processing can correspond to methods, functions, procedures, subroutines, subroutines, and so on.

Fig. 1 is a schematic structural diagram of a projection objective provided by an embodiment of the present invention. As shown in FIG. 1, the projection objective lens includes a first lens group 110 with positive refractive power, a second lens group 120 with negative refractive power, and a third lens group 120 with positive refractive power, which are sequentially arranged from the object plane 10 along the optical axis. The lens group 130, the aperture stop 30, the fourth lens group 140 with positive refractive power, the fifth lens group 150 with negative refractive power, and the sixth lens group 160 with positive refractive power, the first lens group 110 and the The six lens group 160 is symmetric based on the aperture stop 30, the second lens group 120 and the fifth lens group 150 are symmetric based on the aperture stop 30, and the third lens group 130 and the fourth lens group 140 are symmetric based on the aperture stop 30. The first lens group is used to correct spherical aberration, astigmatism and field curvature related to the field distribution, the second lens group is used to match and compensate the aberrations generated by the first lens group and the third lens group, and the third lens group is used to correct chromatic aberration , Constant term spherical aberration and astigmatism, the fourth lens group is used to compensate the coma and distortion produced by the third lens group, the fifth lens group is used to compensate the coma and distortion produced by the second lens group, and the sixth lens group is used To compensate for the coma and distortion produced by the first lens group.

And, the projection objective satisfies the following relationship:

-0.7<f1/f2<-0.3

-1.1<f2/f3<-0.6

-1.1<f5/f4<-0.6

-0.7<f6/f5<-0.3

Among them, f1 is the focal length of the first lens group, f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, f4 is the focal length of the fourth lens group, f5 is the focal length of the fifth lens group, and f6 is the focal length of the fifth lens group. The focal length of the six lens group.

It must be noted that in this embodiment, the projection objective is symmetrical about the aperture stop 30, so there is no coma, distortion, and chromatic aberration of magnification. Continuing to refer to FIG. 1, the aperture stop 30 is located at the middle position of the third lens group 130 and the fourth lens group 140.

The projection objective provided by this embodiment includes a first lens group 110 with positive refractive power, a second lens group 120 with negative refractive power, and a third lens with positive refractive power, which are sequentially arranged from the object plane 10 along the optical axis. Group 130, aperture stop 30, fourth lens group 140 with positive refractive power, fifth lens group 150 with negative refractive power, and sixth lens group 160 with positive refractive power, first lens group 110 and sixth lens group 110 The lens group 160 is symmetrical based on the aperture stop 30, the second lens group 120 and the fifth lens group 150 are symmetrical based on the aperture stop 30, the third lens group 130 and the fourth lens group 140 are symmetrical based on the aperture stop 30, and the projection objective meets the following Relations: -0.7<f1/f2<-0.3, -1.1<f2/f3<-0.6, -1.1<f5/f4<-0.6, -0.7<f6/f5<-0.3, where f1 is the first lens The focal length of the lens group, f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, f4 is the focal length of the fourth lens group, f5 is the focal length of the fifth lens group, and f6 is the focal length of the sixth lens group. The diameter of the object field of view and the applicable wavelength range of the projection objective lens with the above-mentioned structure are relatively large, so that the projection objective lens can be compatible with step exposure and scanning mode exposure, compatible with ghi three-line wavelength and i single-line wavelength, and compatible with mercury light sources and The LED light source significantly improves the compatibility of the projection objective and improves the modularization level of the exposure system.

Illustratively, the maximum diameter of the image-side field of view of the projection objective in this embodiment is 72mm. Such a setting allows the projection objective to be applied to either a step-by-step exposure system with a 54mm*33.5mm field of view. Stepping or scanning exposure system with 26.5mm*67mm field of view, which realizes the compatibility of projection objective lens in stepping exposure and scanning exposure. It can be understood that the projection objective in this embodiment can be applied to all exposure systems with a field of view diameter of less than or equal to 72 mm, and is not limited to exposure systems with a field of view of the above two sizes.

Optionally, the applicable wavelength range of the projection objective is 360-440mm. It must be noted that the wavelength of the i-line in the light source is 365nm, the wavelength of the h-line is 405nm, and the wavelength of the g-line is 436nm. The applicable wavelength range of the projection objective in this embodiment is 360-440mm, the i-line, h-line and g The wavelength of the light source is within this range, and referring to Table 1 and Table 2, the spectrum of the mercury lamp light source and the LED light source are also within the above range, so that the projection objective lens can be compatible with the mercury light source and the LED light source, and compatible with the i-line wavelength and ghi three-line wavelength. In addition, the exposure output of the exposure system is directly proportional to the maximum diameter of the image-side field of view of the projection objective. Such a large maximum image-side field of view makes the exposure system using the projection objective have a higher yield.

Table 1

Table 2

Optionally, all of each lens group (for example: the first lens group, the second lens group, the third lens group, the fourth lens group, the fifth lens group, and the sixth lens group) The lens can be a spherical lens.

It must be noted that the processing difficulty and processing cost of aspheric mirrors are relatively high, and spherical mirrors are easier to detect and integrate compared to aspheric mirrors. Therefore, setting all the lenses in the projection objective as spherical mirrors can reduce the processing difficulty and processing of the projection objective. Cost, convenient lens The beneficial effect of the integration of detection and projection objectives.

Illustratively, the magnification of the projection objective lens may be -1.

Optionally, the conjugate distance of the projection objective lens may be 900 nm.

It must be noted that the small conjugate distance indicates that the lens has a high degree of integration, a small axial length, and takes up less space in the exposure system, which is beneficial to the high integration of the exposure system.

In this embodiment, both the object distance and the image distance of the projection objective lens can be greater than 40 mm.

It must be noted that the above-mentioned object distance and image distance are large, so that there is a large assembly space on the object side and the image side, thereby reducing the difficulty of assembling parts.

Optionally, the image-side numerical aperture of the projection objective lens may be 0.18.

It must be noted that the numerical aperture of the image side is proportional to the resolution, and the above-mentioned larger numerical aperture makes the resolution of the projection objective lens higher.

In summary, the projection objective provided by this embodiment can achieve high compatibility while also having high resolution and productivity.

Exemplarily, referring to FIG. 1, the first lens group 110 includes a first lens 111, a second lens 112, a third lens 113, and a fourth lens 114 sequentially arranged along the optical axis. The first lens 111 is a biconcave lens. The second lens 112 is a meniscus lens made of low-dispersion materials, the third lens 113 is a meniscus lens made of low-dispersion materials, and the fourth lens 114 is a biconvex lens made of high-dispersion materials. The second lens group 120 includes a fifth lens 121 and a sixth lens 122 arranged in sequence along the optical axis. The fifth lens 121 is a biconvex lens made of low-dispersion materials, and the sixth lens 122 is a biconcave lens made of high-dispersion materials. The third lens group 130 includes a seventh lens 131, an eighth lens 132, a ninth lens 133, and a tenth lens 134 arranged in sequence along the optical axis. The seventh lens 131 is a biconcave lens and is made of a low-dispersion material; the eighth lens 132 Double The convex lens is made of high-dispersion material. The ninth lens 133 is a meniscus lens and is made of low-dispersion material. The tenth lens 134 is a biconvex lens made of high-dispersion material.

Illustratively, the high-dispersion material may be selected from CAF2, SILICA, and SFSL5Y.

In some embodiments, the materials of the first lens 111, the fourth lens 114, the sixth lens 122, the eighth lens 132, and the tenth lens 134 all include at least one of CAF2, SILICA, and SFSL5Y.

Illustratively, the low-dispersion material may be selected from PBL35Y, PBL6Y, and PBL1Y.

In some embodiments, the materials of the second lens 112, the third lens 113, the fifth lens 121, the seventh lens 131, and the ninth lens 133 all include at least one of CAF2, SILICA, and SFSL5Y.

It must be noted that the high-dispersion material and the low-dispersion material in this embodiment can also be other materials that meet the corresponding dispersion requirements. This embodiment only uses the above-mentioned materials as an example for illustrative description.

Table 3 provides a design value of the projection objective lens in this embodiment. The radius R column in Table 3 represents the radius of curvature of the lens. A positive radius R represents that the center of curvature of the lens is on the right side of the surface, and a negative radius R represents that the center of curvature of the lens is on the left side of the surface. 1E+18 represents the surface is flat, OBJ represents the object surface, STOP represents the aperture stop, and IMA represents the image surface. In the table, the material column "AIR" represents the air gap between the lens and the lens, the filling gas is air, and the non-AIR material in the material column refers to the specific lens material type. The half-aperture column refers to half of the maximum clear aperture of the lens surface. The thickness d in the table represents the air gap or the thickness of the optical element, the thickness of the optical element or the thickness of two optical elements The interval refers to the on-axis distance from this surface to the next surface, and all dimensions are in millimeters.

table 3

The conjugate distance of the projection objective designed according to the parameters in Table 1 is 900mm, the magnification is -1, the maximum diameter of the object field of view is 72mm, the object and image distances are both 40.08mm, and the image side numerical aperture is 0.18. The minimum resolution that can be achieved is 1μm.

The experiment was carried out with the exposure system of the projection objective lens with the parameters in Table 1, and the experimental data and analysis results were as follows:

Fig. 2 is a diagram of ray aberration of a projection objective provided by an embodiment of the present invention. The light source of the exposure system used is a mercury lamp light source. In Figure 2, the three rows of graphs from bottom to top represent the aberration distribution of the object field points of different heights at the pupil. The two graphs in each row represent the pupil meridian and sagittal aberration distribution, each The abscissa of the figure represents the height on the pupil, the center point represents the center of the pupil, and the ordinate represents the aberration. The different curves in each figure represent the aberration curves at each wavelength. 2 that the maximum aberration of each field of view point is less than 0.002306 mm, indicating that the wave aberration of the objective lens is well corrected, and the chromatic aberration between each wavelength is well corrected. It must be noted that the different types of line segments in Figure 2 represent image quality at different wavelengths.

Fig. 3 is a vertical axis chromatic aberration diagram of a projection objective provided by an embodiment of the present invention. The light source of the exposure system used is a mercury lamp light source. In Figure 3, the ordinate is the height of the object, and the abscissa is the chromatic aberration value of the vertical axis at each height of the object. "Short" is 365nm wavelength, "Long" is 435nm wavelength, "Ref" is 405nm wavelength, "Short-Long" "The curve is the vertical chromatic aberration value of 365nm and 435nm wavelengths at each field height, and the "Short-Ref" curve is the vertical chromatic aberration value of 365nm and 405nm wavelengths at each field height. It can be seen from Fig. 3 that the maximum vertical axis chromatic aberration of the objective lens is 54 nm. The vertical chromatic aberration of the bright objective lens has been well corrected.

Fig. 4 is a telecentric curve of a projection objective provided by an embodiment of the present invention. The light source of the exposure system used is a mercury lamp light source. In Figure 4, the abscissa is the height of the object field of view, and the ordinate is the size of the telecentricity in each field of view. The two curves in the figure are the telecentricity of the object mirror image and the telecentricity of the object. The entire field of view can be seen from the figure. The maximum value of the inner object-side telecentricity and the image-side telecentricity does not exceed 5.61mrad, and the telecentricity of the objective lens has been well corrected.

FIG. 5 is a diagram of ray aberration of another projection objective provided by an embodiment of the present invention. The light source of the exposure system used is an LED light source. In Figure 5, the three rows of graphs from bottom to top represent the aberration distribution at the pupil at different heights of the object field of view. The two graphs in each row represent the pupil meridian and sagittal aberration distributions, each The abscissa of the figure represents the height on the pupil, the center point represents the center of the pupil, and the ordinate represents the aberration. The different curves in each figure represent the aberration curves at each wavelength. It can be seen from Figure 5 that the maximum aberration of each field of view point is less than 0.002478mm, indicating that the wave aberration of the objective lens is well corrected. It must be noted that the different types of line segments in Figure 5 represent image quality at different wavelengths.

Fig. 6 is a vertical axis chromatic aberration diagram of another projection objective provided by an embodiment of the present invention. The light source of the exposure system used is an LED light source. In Figure 6, the ordinate is the height of the object, and the abscissa is the chromatic aberration value of the vertical axis at each height of the object. "Short" is the wavelength of 365nm, "Long" is the wavelength of 435nm, "Ref" is the wavelength of 405nm, "Short-Long" "The curve is the vertical chromatic aberration value of 365nm and 435nm wavelengths at each field height, and the "Short-Ref" curve is the vertical chromatic aberration value of 365nm and 405nm wavelengths at each field height. It can be seen from Fig. 6 that the maximum vertical axis chromatic aberration of the objective lens is 66 nm, indicating that the vertical axis chromatic aberration of the objective lens has been well corrected.

Fig. 7 is a telecentric curve of another projection objective provided by an embodiment of the present invention. Pick The light source of the exposure system used is an LED light source. In Figure 7, the abscissa is the height of the object field of view, and the ordinate is the size of the telecentricity in each field of view. The two curves in the figure are the telecentricity of the object mirror image and the telecentricity of the object. From Figure 7, it can be seen that the entire field of view The maximum value of object-side telecentricity and image-side telecentricity does not exceed 5.62mrad, and the telecentricity of the objective lens has been well corrected.

Table 4 provides another design value of the projection objective lens in this embodiment. The radius R column in Table 4 represents the radius of curvature of the lens. A positive radius R represents that the center of curvature of the lens is on the right side of the surface, and a negative radius R represents that the center of curvature of the lens is on the left side of the surface. 1E+18 represents the surface is flat, OBJ represents the object surface, STOP represents the aperture stop, and IMA represents the image surface. In the table, the material column "AIR" represents the air gap between the lens and the lens, the filling gas is air, and the non-AIR material in the material column refers to the specific lens material type. The half-aperture column refers to half of the maximum clear aperture of the lens surface. The thickness d column in the table represents the air gap or the thickness of the optical element. The thickness of the optical element or the distance between two optical elements refers to the on-axis distance from this surface to the next surface. All dimensions are in millimeters.

Table 4

The conjugate distance of the projection objective designed according to the parameters in Table 2 is 900mm, the magnification is -1, the maximum diameter of the object field of view is 72mm, the object and image distances are both 45mm, and the image side numerical aperture is 0.18. The minimum resolution achieved is 1μm.

The experiment is carried out with the optical system of the projection objective lens with the parameters in Table 1, and the experimental data and analysis results are as follows:

FIG. 8 is a diagram of ray aberration of another projection objective provided by an embodiment of the present invention. The light source of the exposure system used is a mercury lamp light source. In Figure 8, the three rows of graphs from bottom to top represent the aberration distribution at the pupil of the object field of view points of different heights, and the two graphs in each row represent the pupil meridian and sagittal respectively. Aberration distribution, the abscissa of each picture represents the height on the pupil, the center point represents the pupil center, and the ordinate represents the aberration size, and the different curves of each picture represent the aberration curves at each wavelength. It can be seen from Fig. 8 that the maximum aberration of each field of view point is less than 0.002132mm, indicating that the wave aberration of the objective lens is well corrected, and the chromatic aberration between each wavelength is well corrected. It must be noted that the different types of line segments in Fig. 8 represent image quality at different wavelengths.

Fig. 9 is a vertical axis chromatic aberration diagram of yet another projection objective provided by an embodiment of the present invention. The light source of the exposure system used is a mercury lamp light source. In Figure 9 the ordinate is the height of the object, and the abscissa is the vertical chromatic aberration value at each height of the object. "Short" is the wavelength of 365nm, "Long" is the wavelength of 435nm, "Ref" is the wavelength of 405nm, "Short-Long" "The curve is the vertical chromatic aberration value of 365nm and 435nm wavelengths at each field height, and the "Short-Ref" curve is the vertical chromatic aberration value of 365nm and 405nm wavelengths at each field height. It can be seen from Fig. 9 that the maximum vertical axis chromatic aberration of the objective lens is 63nm, indicating that the vertical axis chromatic aberration of the objective lens has been well corrected.

FIG. 10 is a telecentric curve of another projection objective provided by an embodiment of the present invention. The light source of the exposure system used is a mercury lamp light source. In Figure 10, the abscissa is the height of the field of view of the object, and the ordinate is the size of the telecentricity in each field of view. The two curves in the figure are the telecentricity of the object mirror image and the telecentricity of the object. The maximum value of square telecentricity and image-side telecentricity does not exceed 5.59mrad, and the telecentricity of the objective lens has been well corrected.

FIG. 11 is a diagram of ray aberration of another projection objective provided by an embodiment of the present invention. The light source using the three-dimensional exposure system is an LED light source. In Figure 11, the three rows of graphs from bottom to top represent the aberration distribution at the pupil of the object field of view points of different heights. The two graphs in each row represent the pupil meridian and sagittal aberration distribution, each The abscissa of the figure represents the height on the pupil, the center point represents the center of the pupil, and the ordinate represents the aberration. The different curves in each figure represent the respective waves Aberration curve under long. It can be seen from Figure 5 that the maximum aberration of each field of view point is less than 0.002294mm, indicating that the wave aberration of the objective lens is well corrected. It must be noted that the different types of line segments in FIG. 11 represent the image quality at different wavelengths.

Fig. 12 is a vertical axis chromatic aberration diagram of yet another projection objective provided by an embodiment of the present invention. The light source of the exposure system used is an LED light source. In Figure 12, the ordinate is the height of the object, and the abscissa is the chromatic aberration value of the vertical axis at each height of the object. "Short" is the wavelength of 365nm, "Long" is the wavelength of 435nm, "Ref" is the wavelength of 405nm, "Short-Long" "The curve is the vertical chromatic aberration value of 365nm and 435nm wavelengths at each field height, and the "Short-Ref" curve is the vertical chromatic aberration value of 365nm and 405nm wavelengths at each field height. It can be seen from Fig. 12 that the maximum vertical chromatic aberration of the objective lens is 75 nm, which indicates that the vertical chromatic aberration of the objective lens has been well corrected.

FIG. 13 is a telecentric curve of another projection objective provided by an embodiment of the present invention. The light source of the exposure system used is an LED light source. In Figure 13 the abscissa is the height of the object field of view, and the ordinate is the size of the telecentricity in each field of view. The two curves in the figure are the telecentricity of the object mirror image and the telecentricity of the object. The maximum value of object-side telecentricity and image-side telecentricity does not exceed 5.58mrad, and the telecentricity of the objective lens has been well corrected.

Fig. 14 is a schematic structural diagram of an exposure system provided by an embodiment of the present invention. As shown in FIG. 14, the exposure system includes the projection objective 5 of any embodiment of the present invention. Continuing to refer to FIG. 14, the exposure system further includes a light source assembly 1, a quartz rod 2, a relay group 3, a mask 4, and a silicon wafer 6. It must be noted that the light source assembly 1 shown in FIG. 14 is an LED light source assembly. In other embodiments of the example, the light source assembly 1 may also be a mercury lamp light source assembly.

10‧‧‧Object plane

30‧‧‧Aperture diaphragm

110‧‧‧First lens group

111‧‧‧First lens

112‧‧‧Second lens

113‧‧‧third lens

114‧‧‧Fourth lens

120‧‧‧Second lens group

121‧‧‧Fifth lens

122‧‧‧Sixth lens

130‧‧‧Third lens group

131‧‧‧Seventh lens

132‧‧‧Eighth lens

133‧‧‧Ninth lens

134‧‧‧Tenth lens

140‧‧‧Fourth lens group

150‧‧‧Fifth lens group

160‧‧‧Sixth lens group

Claims (12)

A projection objective lens, which is characterized by comprising a first lens group with positive refractive power, a second lens group with negative refractive power, and a third lens group with positive refractive power, which are arranged in sequence along the optical axis from the object surface. An aperture stop, a fourth lens group with positive refractive power, a fifth lens group with negative refractive power, and a sixth lens group with positive refractive power; The first lens group and the sixth lens group are based on the aperture diaphragm symmetry, the second lens group and the fifth lens group are based on the aperture diaphragm symmetry, and the third lens group and the fourth lens group are based on the aperture diaphragm. Symmetrical aperture The first lens group is used to correct spherical aberration, astigmatism and field curvature related to the field distribution, the second lens group is used to match and compensate the aberrations generated by the first lens group and the third lens group, the third lens The group is used to correct chromatic aberration, constant term spherical aberration and astigmatism. The fourth lens group is used to compensate for the coma and distortion produced by the third lens group. The fifth lens group is used to compensate for the coma produced by the second lens group. Aberration and distortion, the sixth lens group is used to compensate coma and distortion generated by the first lens group; The aforementioned projection objective satisfies the following relationship: -0.7<f1/f2<-0.3 -1.1<f2/f3<-0.6 -1.1<f5/f4<-0.6 -0.7<f6/f5<-0.3 Among them, f1 is the focal length of the first lens group, f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, f4 is the focal length of the fourth lens group, f5 is the focal length of the fifth lens group, and f6 is the focal length of the fifth lens group. The focal length of the six lens group. Such as the projection objective described in item 1 of the scope of patent application, wherein the applicable wavelength range of the aforementioned projection objective is 360-440mm. For the projection objective described in item 1 of the scope of patent application, the maximum diameter of the image side field of view of the aforementioned projection objective is 72 mm. As described in the first item of the scope of patent application, the first lens group includes a first lens, a second lens, a third lens, and a fourth lens that are sequentially arranged along the optical axis; the first lens is a double lens. The concave lens is made of high-dispersion material; the aforementioned second lens is a meniscus lens and is made of low-dispersion material; the aforementioned third lens is a meniscus lens, made of low-dispersion material; the aforementioned fourth lens is a biconvex lens, made of high-dispersion material constitute; The second lens group includes a fifth lens and a sixth lens arranged in sequence along the optical axis; the fifth lens is a biconvex lens and is composed of a low-dispersion material; the sixth lens is a biconcave lens and is composed of a high-dispersion material; The third lens group includes a seventh lens, an eighth lens, a ninth lens, and a tenth lens that are sequentially arranged along the optical axis; the seventh lens is a double-concave lens and is made of a low-dispersion material; the eighth lens is a double-convex lens , Made of high-dispersion material; the aforementioned ninth lens is a meniscus lens, made of low-dispersion material; the aforementioned tenth lens is a biconvex lens, made of high-dispersion material. For the projection objective described in item 4 of the scope of patent application, the aforementioned high-dispersion material is selected from CAF2, SILICA and SFSL5Y. The projection objective described in item 4 of the scope of patent application, wherein the aforementioned low-dispersion material is selected from PBL35Y, PBL6Y and PBL1Y. As the projection objective described in item 1 of the scope of patent application, all the lenses in each lens group are spherical lenses, the first lens group, the second lens group, the third lens group, The fourth lens group, the fifth lens group, and the sixth lens group are all the lens groups. Such as the projection objective described in item 1 of the scope of patent application, wherein the magnification of the aforementioned projection objective is -1. As the projection objective described in the first item of the scope of patent application, the conjugate distance of the aforementioned projection objective is 900 nm. Such as the projection objective described in item 1 of the scope of patent application, wherein the object and image distances of the aforementioned projection objective are both greater than 40 mm. For the projection objective described in item 1 of the scope of patent application, the image-side numerical aperture of the aforementioned projection objective is 0.18. An exposure system, characterized in that it includes the projection objective described in any one of items 1 to 11 of the aforementioned patent application.

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