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KR-102964284-B1 - HIGH RESOLUTION LOW MAGNIFICATION OBJECTIVE LENS SYSTEM

KR102964284B1KR 102964284 B1KR102964284 B1KR 102964284B1KR-102964284-B1

Abstract

The high-resolution, low-magnification objective lens system (100) of the present invention satisfies an object-side numerical aperture (NAO) of 0.09 < NAO < 0.15, and is configured to include nine lenses aligned at a predetermined interval on a coaxial line, wherein the object-side numerical aperture (NAO) satisfies 0.09 < NAO < 0.15, a coaxial illumination beam splitter of 20 mm or more is provided on the object side, and the system comprises nine lenses aligned at a predetermined interval on a coaxial line, wherein the system comprises a beam splitter (BS) located close to the object, a first lens group consisting of a first lens (101), a second lens (102), and a third lens (103), a second lens group consisting of a fourth lens (104) and a fifth lens (105), a third lens group consisting of an aperture (A), a sixth lens (106), and a seventh lens (107), and a fourth lens group consisting of an eighth lens (108) and a ninth lens (109) located close to the image, wherein the refractive power (P1) of the first lens group is a positive refractive power, and the second lens group's The refractive power (P2) is a positive refractive power, the refractive power (P3) of the third group lens is a negative refractive power, and the refractive power (P4) of the fourth group lens is a positive refractive power.

Inventors

  • 여필상
  • 류영남
  • 고동완

Assignees

  • 한국전광(주)

Dates

Publication Date
20260513
Application Date
20251202

Claims (20)

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  8. It is configured such that the object-side numerical aperture (NAO) satisfies 0.09 < NAO < 0.15, a coaxial illumination beam splitter of 20 mm or more is provided on the object side, and it includes nine lenses aligned at predetermined intervals along the coaxial line, It includes a beam splitter (BS) positioned close to an object, a first group of lenses consisting of a first lens (101), a second lens (102), and a third lens (103), a second group of lenses consisting of a fourth lens (104) and a fifth lens (105), an aperture (A), a third group of lenses consisting of a sixth lens (106) and a seventh lens (107), and a fourth group of lenses consisting of an eighth lens (108) and a ninth lens (109) positioned close to an image. A high-resolution, low-magnification objective lens system (100) characterized in that the refractive power (P1) of the first group lens is a positive refractive power, the refractive power (P2) of the second group lens is a positive refractive power, the refractive power (P3) of the third group lens is a negative refractive power, and the refractive power (P4) of the fourth group lens is a positive refractive power.
  9. A high-resolution, low-magnification objective lens system (100) according to claim 8, wherein the refractive power (P1) of the first group lens is 0.000mm -1 < P1 < 0.010mm -1 , the refractive power (P2) of the second group lens is 0.005mm -1 < P2 < 0.020mm -1 , the refractive power (P3) of the third group lens is -0.015mm -1 < P3 < 0.000mm -1, and the refractive power (P4) of the fourth group lens is 0.000mm -1 < P4 < 0.020mm -1 .
  10. A high-resolution, low-magnification objective lens system (100) according to claim 9, wherein the refractive power (P1) of the first group lens is P1 = 0.003 mm - 1 , the refractive power (P2) of the second group lens is P2 = 0.014 mm - 1 , the refractive power (P3) of the third group lens is P3 = -0.010 mm - 1, and the refractive power (P4) of the fourth group lens is P4 = 0.008 mm - 1 .
  11. A high-resolution, low-magnification objective lens system (100) according to claim 8, wherein the refractive power (P1-1) of the first lens (101) is a positive refractive power, the refractive power (P1-2) of the second lens (102) is a negative refractive power, the refractive power (P2-4) of the fourth lens (104) is a positive refractive power, the refractive power (P2-5) of the fifth lens (105) is a negative refractive power, the refractive power (P4-8) of the eighth lens (108) is a positive refractive power, and the refractive power (P4-9) of the ninth lens (109) is a positive refractive power.
  12. A high-resolution, low-magnification objective lens system (100) characterized in that, in order to correct chromatic aberration caused by the use of a wide range of wavelengths in any one of claims 8 to 11, the refractive index (Nd) of the first lens (101) is Nd > 1.70000 and the Abbe number (Vd) is Vd < 25.00, the refractive index (Nd) of the second lens (102) is Nd < 1.70000 and the Abbe number (Vd) is Vd > 50.00, and the refractive index (Nd) of the ninth lens (109) is Nd > 1.70000 and the Abbe number (Vd) is Vd < 50.00.
  13. A high-resolution low-magnification objective lens system (100) according to claim 12, wherein the refractive index (Nd) of the first lens (101) is Nd = 1.94596 and the Abbe number (Vd) is Vd = 17.94, the refractive index (Nd) of the second lens (102) is Nd = 1.67790 and the Abbe number (Vd) is Vd = 55.56, and the refractive index (Nd) of the ninth lens (109) is Nd = 1.88300 and the Abbe number (Vd) is Vd = 40.87.
  14. A high-resolution, low-magnification objective lens system (100) according to any one of claims 8 to 11, wherein, in order to secure a long working distance from the object side and the upper side, the optical path (Lo) from the object to the incident surface of the first lens (101) and the total focal length (f) of the lens are Lo/f > 0.50, and the optical path (Li) from the exit surface of the ninth lens (109) to the upper surface and the total focal length (f) of the lens are Li/f > 0.70.
  15. A high-resolution, low-magnification objective lens system (100) according to claim 14, wherein the optical path (Lo) from the object to the incident plane of the first lens (101) and the total focal length (f) of the lens are Lo/f = 0.68, and the optical path (Li) from the exit plane of the ninth lens (109) to the image plane and the total focal length (f) of the lens are Li/f = 0.94.
  16. A high-resolution, low-magnification objective lens system (100) according to any one of claims 8 to 11, wherein, in order to correct spherical aberration and image plane curvature, the incident surface of the first lens (101) is convex toward the object, the incident surface of the fourth lens (104) is convex toward the object, the exit surface of the fifth lens (105) is concave toward the upper side, and the exit surface of the ninth lens (109) is convex toward the upper side.
  17. A high-resolution, low-magnification objective lens system (100) characterized in that, in any one of claims 8 to 11, the fifth lens (105), the sixth lens (106), and the eighth lens (108) are bonded lenses to improve the assemblability of the lens.
  18. The object-side numerical aperture (NAO) satisfies 0.09 < NAO < 0.15, and a coaxial illumination beam splitter of 20 mm or more is provided on the object side, and is configured to include 10 lenses aligned at predetermined intervals along the coaxial line, It includes a beam splitter (BS) positioned close to an object, a first group of lenses consisting of a first lens (201), a second lens (202) and a third lens (203), a second group of lenses consisting of a fourth lens (204) and a fifth lens (205), an aperture (A), a third group of lenses consisting of a sixth lens (206), and a fourth group of lenses consisting of a seventh lens (207), an eighth lens (208), a ninth lens (209) and a tenth lens (210) positioned close to an image. A high-resolution, low-magnification objective lens system (200) characterized in that the refractive power (P1) of the first group lens is a positive refractive power, the refractive power (P2) of the second group lens is a positive refractive power, the refractive power (P3) of the third group lens is a negative refractive power, and the refractive power (P4) of the fourth group lens is a positive refractive power.
  19. A high-resolution, low-magnification objective lens system (200) according to claim 18, wherein the refractive power (P1) of the first group lens is 0.000mm -1 < P1 < 0.010mm -1 , the refractive power (P2) of the second group lens is 0.005mm -1 < P2 < 0.020mm -1 , the refractive power (P3) of the third group lens is -0.015mm -1 < P3 < 0.000mm -1, and the refractive power (P4) of the fourth group lens is 0.000mm -1 < P4 < 0.020mm -1 .
  20. A high-resolution, low-magnification objective lens system (200) according to claim 19, wherein the refractive power (P1) of the first group lens is P1 = 0.006 mm - 1 , the refractive power (P2) of the second group lens is P2 = 0.007 mm - 1 , the refractive power (P3) of the third group lens is P3 = -0.003 mm - 1, and the refractive power (P4) of the fourth group lens is P4 = 0.008 mm - 1 .

Description

High Resolution Low Magnification Objective Lens System The present invention relates to a high-resolution, low-magnification objective lens system, and more specifically, to a high-resolution, low-magnification objective lens system capable of rapidly detecting defects in a wider inspection area during an inspection process in semiconductor manufacturing. In semiconductor manufacturing processes, low-magnification objective lenses are used for inspecting wafers or substrates. They play an essential role in rapidly inspecting large areas by enabling a wide field of view, rapid inspection and alignment, a long working distance, and the realization of high resolution and clarity. Specifically, a wide field of view is possible, so although the magnification is low, the field of view (FOV) is very wide, allowing a large portion of a large sample, such as a semiconductor wafer, to be observed with a single image acquisition. Additionally, rapid inspection and alignment are possible, so the overall pattern alignment status can be checked or the location of major defects can be quickly identified before inspecting fine parts with a high-magnification lens. Furthermore, due to the long operating distance, the movement of samples or jigs within the inspection equipment is less restricted, reducing the risk of collision; additionally, high resolution and clarity can be achieved, providing uniform resolution and low distortion over a wide area rather than simple magnification. Such low-magnification objective lenses are widely applied in initial visual inspection/macro inspection tasks to check the overall surface condition after wafer loading, automated optical inspection tasks that rapidly scan large areas to locate suspected defect zones and then switch to high-magnification lenses for precise analysis, and measurement and alignment tasks that locate reference marks within a wide field of view for accurate alignment of masks and wafers in semiconductor photolithography processes. Consequently, a continuous market demand for the development of technology capable of expanding inspection areas and identifying suspected defect areas more quickly is emerging as a problem. FIG. 1 is a schematic diagram of a high-resolution, low-magnification objective lens system according to a preferred first embodiment of the present invention; FIG. 2 is a schematic diagram of a high-resolution, low-magnification objective lens system according to a preferred second embodiment of the present invention; and FIG. 3 is a schematic diagram of a high-resolution, low-magnification objective lens system according to a preferred third embodiment of the present invention. The high-resolution, low-magnification objective lens system of the present invention is configured such that, in order to quickly detect defects in a wider inspection area, the object-side numerical aperture (NAO) satisfies 0.09 < NAO < 0.15, and a coaxial illumination beam splitter of 20 mm or more is provided on the object side. The high-resolution, low-magnification objective lens system of the present invention comprises n lenses aligned at predetermined intervals along a coaxial line, and includes a beam splitter located close to an object, a first group of lenses consisting of the first to m-th lenses, a second group of lenses consisting of the m+1-th to k-th lenses, an aperture, a third group of lenses consisting of the k+1-th to x-th lenses, and a fourth group of lenses consisting of the x+1-th to n-th lenses located close to an image. Here, the refractive power (P1) of the first group lens is a positive refractive power, preferably 0.000mm -1 < P1 < 0.010mm -1 , the refractive power (P2) of the second group lens is a positive refractive power, preferably 0.005mm -1 < P2 < 0.020mm -1 , the refractive power (P3) of the third group lens is a negative refractive power, preferably -0.015mm -1 < P3 < 0.000mm -1 , and the refractive power (P4) of the fourth group lens is a positive refractive power, preferably 0.000mm -1 < P4 < 0.020mm -1 . Also, the refractive power of the first lens of the first group (P1-1) is positive, the refractive power of the second lens (P1-2) is negative, the refractive power of the m+1th lens of the second group (P2-m+1) is positive, the refractive power of the m+2th lens (P2-m+2) is negative, and the refractive power of the x+1th lens of the fourth group (P2-x+1) is positive. In order to correct chromatic aberration caused by the use of a wide range of wavelengths, the present invention is configured such that the refractive index (Nd) of the first lens of the first group is Nd > 1.70000 and the Abbe number (Vd) is Vd < 25.00, the refractive index (Nd) of the second lens is Nd < 1.70000 and the Abbe number (Vd) is Vd > 50.00, and the refractive index (Nd) of the nth lens of the fourth group is Nd > 1.70000 and the Abbe number (Vd) is Vd < 50.00. In addition, to ensure a long working distance on both the object side and the image side, the optica