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CN-116804800-B - Double telecentric projection optical system with adjustable multiplying power

CN116804800BCN 116804800 BCN116804800 BCN 116804800BCN-116804800-B

Abstract

The variable magnification projection optical system is a double telecentric optical path, and comprises a front lens group, an aperture diaphragm and a rear lens group along the optical axis direction, wherein the front lens group comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged from the object space to the image space, the rear lens group comprises a fifth lens, a sixth lens, a seventh lens and an eighth lens which are sequentially arranged from the object space to the image space, and magnification adjustment is realized by controlling the variable magnification lens to move along the optical axis direction. The invention can realize focal length change by utilizing the movement of the single lens on the basis of not increasing the number of optical parts under the condition of keeping good double telecentric projection optical characteristics and good optical imaging quality, and conveniently and effectively correct or adjust the projection multiplying power of an optical system, and all lenses selected by the optical system are spherical surfaces and do not contain aspherical lenses, thereby greatly reducing the difficulty and cost of processing, detecting and correcting.

Inventors

  • HUO DAYUN
  • XI FANGFANG
  • GUO YUHAN

Assignees

  • 锡凡半导体无锡有限公司

Dates

Publication Date
20260505
Application Date
20230525

Claims (8)

  1. 1. The double telecentric projection optical system with adjustable multiplying power adopts a double telecentric structure, and the principal rays of an object space and an image space are parallel to an optical axis, and is characterized by comprising a front lens group (1), an aperture diaphragm (2) and a rear lens group (3) which are sequentially arranged from the object space to the image space; The front lens group (1) is composed of a first positive focal power lens group; The aperture diaphragm (2) is positioned on the confocal plane of the front lens group (1) and the rear lens group (3); The rear lens group (3) is composed of a second positive focal power lens group, and the position relation of the corresponding lenses in the rear lens group (3) is moved to form a zoom lens to adjust the magnification of the optical system; the current lens group (1) and the rear lens group (3) comprise 8 lenses, the front lens group (1) is composed of a first lens (L1), a second lens (L2), a third lens (L3) and a fourth lens (L4), and the rear lens group (3) is composed of a fifth lens (L5), a sixth lens (L6), a seventh lens (L7) and an eighth lens (L8); the optical system satisfies the following relation: relation 1-0.65 < F3/F4< -0.3; relation 2-0.65 < F3/Fo <0; relation 3-0.18 < F6/F7< -0.1; Relation 4-0.08 < F6/Fi < -0.04; Wherein F3 is the focal length of the third lens (L3), F4 is the focal length of the fourth lens (L4), fo is the combined focal length of the front lens group (1), F6 is the focal length of the sixth lens (L6), F7 is the focal length of the seventh lens (L7), and Fi is the combined focal length of the rear lens group (3).
  2. 2. The double telecentric projection optical system of claim 1, wherein the first lens (L1), the second lens (L2), the fourth lens (L4), the fifth lens (L5), the seventh lens (L7) and the eighth lens (L8) are convex lenses, the third lens (L3) and the sixth lens (L6) are concave lenses, and the seventh lens (L7) can form a zoom lens by moving in the rear lens group (3) to adjust the magnification of the optical system.
  3. 3. The double telecentric projection optical system according to claim 2, wherein the third lens (L3) and the sixth lens (L6) are biconcave lenses.
  4. 4. The double telecentric projection optical system with adjustable magnification according to claim 1, wherein the working wavelength of an objective lens system consisting of the front lens group (1), the aperture diaphragm (2) and the rear lens group (3) is near ultraviolet band; The first lens (L1), the second lens (L2), the fourth lens (L4), the fifth lens (L5), the seventh lens (L7) and the eighth lens (L8) adopt crown glass or light crown glass, and the material characteristics thereof satisfy: 1.43<N d <1.65 55.00<V d <85.00 Wherein N d is the refractive index of the lens first lens (L1), the second lens (L2), the fourth lens (L4), the fifth lens (L5), the seventh lens (L7) and the eighth lens (L8), V d is the corresponding Abbe number; The third lens (L3) and the sixth lens (L6) are made of flint glass or light flint glass, and the material characteristics thereof are as follows: 1.53<N d <1.64 35.00<V d <46.00 Wherein N d is the refractive index of the third lens (L3) and the sixth lens (L6), and V d is the corresponding Abbe's number.
  5. 5. The adjustable magnification double telecentric projection optical system of claim 1, wherein all lens surfaces of the optical system are spherical or planar.
  6. 6. The adjustable magnification double telecentric projection optical system of claim 1, wherein the object side and image side working distances of the optical system are both greater than 100mm.
  7. 7. The adjustable magnification double telecentric projection optical system of claim 1, wherein the optical system satisfies the following relationship: relation 5:0< R9/R10<0.45; relation 6-2.5 < R14/T14< -1.26; Wherein R9 is the radius of curvature of the object side of the fifth lens element (L5), R10 is the radius of curvature of the image side of the fifth lens element (L5), R14 is the radius of curvature of the image side of the seventh lens element (L7), and T14 is the clear aperture of the image side of the seventh lens element (L7).
  8. 8. The adjustable magnification double telecentric projection optical system of claim 1, wherein the optical system satisfies the following relationship: relation 7:30.2< T1<39.5; relation 8:64.5< T16<70.5; Wherein T1 is the clear aperture of the object side of the first lens element (L1), and T16 is the clear aperture of the image side of the eighth lens element (L8).

Description

Double telecentric projection optical system with adjustable multiplying power Technical Field The invention relates to an optical system applied to a projection photoetching machine, in particular to a double telecentric projection system with adjustable multiplying power. Background In recent years, projection lithography has been widely used in various fields such as circuit fabrication, machine vision, and semiconductors. With the development of photolithography, the minimum line width of Integrated Circuits (ICs) is becoming smaller and smaller in the production process of circuit substrates, and the requirements for projection lenses are increasing. Because the lens manufacturing process has processing errors, and the substrates manufactured by different devices have fine size differences, when the circuit substrate scanning and the multilayer substrate positioning process are performed, the projection magnification of the optical system needs to be corrected or adjusted according to the actual change of the graph or the magnification so as to ensure the accuracy of the magnification. The double telecentric lens can well meet the requirements of the photoetching projection lens, and because the object space optical path and the image space optical path are double telecentric optical paths, even if the object plane and the image plane deviate from the focal plane, the heights of the object and the image in the direction vertical to the optical axis are unchanged, so that the magnification is hardly changed. The currently published double telecentric lens with adjustable magnification has a large number of lenses forming an optical system, and two or more lenses need to be moved simultaneously to complete magnification adjustment, for example, CN102645749A (publication day is 2012, 08 and 22 days) comprises 12 lenses, and the magnification is adjusted by moving a group of symmetrical lenses, so that the requirements on mechanical structure design and lens processing cost are high. Therefore, how to provide an optical system which can maintain good double telecentric projection optical characteristics and good optical imaging quality and can conveniently and effectively correct or adjust projection magnification is an important technical subject in the industry. Disclosure of Invention The invention aims to provide a double telecentric projection optical system with adjustable multiplying power, which is convenient for correcting or adjusting the projection multiplying power of the optical system when the multiplying power of a projection objective lens drifts. A double telecentric projection optical system with adjustable multiplying power is composed of a double telecentric structure, a front lens group consisting of the first positive focal lens group, an aperture diaphragm arranged on the common focal plane of front lens group and back lens group, and a back lens group consisting of the second positive focal lens group, and a variable-magnification lens consisting of the position relation of the corresponding lenses in the back lens group. As a further improvement of the above technical scheme: the current lens group and the rear lens group include 8 lenses, the front lens group is composed of a first lens, a second lens, a third lens and a fourth lens, and the rear lens group is composed of a fifth lens, a sixth lens, a seventh lens and an eighth lens. The first lens, the second lens, the fourth lens, the fifth lens, the seventh lens and the eighth lens are convex lenses, the third lens and the sixth lens are concave lenses, and the seventh lens can form a variable-magnification lens by moving in the rear lens group, so that the magnification of the optical system is adjusted. The third lens and the sixth lens are biconcave lenses. The working wavelength of an objective lens system formed by the front lens group, the aperture diaphragm and the rear lens group is near ultraviolet band; the first lens, the second lens, the fourth lens, the fifth lens, the seventh lens and the eighth lens adopt crown glass or light crown glass, and the material characteristics of the first lens, the second lens, the fourth lens, the fifth lens, the seventh lens and the eighth lens meet the following conditions: 1.43<Nd<1.65 55.00<Vd<85.00 Wherein Nd is the refractive index of the first lens, the second lens, the fourth lens, the fifth lens, the seventh lens and the eighth lens, vd is the corresponding dispersion coefficient; the third lens and the sixth lens adopt flint glass or light flint glass, and the material characteristics of the third lens and the sixth lens meet the following conditions: 1.53<Nd<1.64 35.00<Vd<46.00 Where Nd is the refractive index of the third lens and the sixth lens, and Vd is the corresponding Abbe's number. All lens surfaces of the optical system are spherical or planar. The working distance between the object space and the image space of the optical system is larger than 100mm. The optical