US-12619053-B2 - Photolithography projection lens

US12619053B2US 12619053 B2US12619053 B2US 12619053B2US-12619053-B2

Abstract

A photolithography projection lens, having a plurality of lens elements and a light diaphragm arranged among them, arranged along an optical axis, and comprising an object side and an image side respectively arranged at the front and rear ends of the plurality of lens elements; wherein: the diopters of the two lenses respectively near the object side and the image side must be positive; each of the lens elements is a single lens without cement; the angle between the chief rays at different image height positions and the optical axis is <1 degree, and the angle between the chief rays at different object height positions and the optical axis is <1 degree; and under the projection of 350˜450 nm wavelength light, it provide the imaging effect of precise magnification.

Inventors

SHENG CHE WU
YU HUNG CHOU
YI HUA LIN
YUAN HUNG SU

Assignees

SUN YANG OPTICS DEVELOPMENT CO., LTD.

Dates

Publication Date: 20260505
Application Date: 20220914

Claims (8)

1 . A photolithography projection lens, comprising: a plurality of lens elements disposed along an optical axis and a light diaphragm arranged amongst the plurality of lens elements along the optical axis, and an object side and an image side are, respectively, defined at front and rear ends of the plurality of lens elements; and a prism set in front of the object side, and negative lens elements of the plurality of lens elements disposed before and after the light diaphragm satisfies an Abbe number of 30<Vd<50, and each of the plurality of lens elements satisfy a refractive index of 1.45<Nd<1.75 and a numerical aperture between 0.08 and 0.21; wherein diopters of two lens elements of the plurality of lens elements that are, respectively, closest to the object side and the image side are positive; wherein each of the plurality of lens elements is formed of a single lens that does not include cement; wherein an angle between chief rays at different image height positions and the optical axis is <1 degree and an angle between chief rays at different object height positions and the optical axis is <1 degree; and thereby responsive to projection of 350˜450 nm wavelength light, an imaging effect of a magnification within a nominal range is generated; wherein at least one of a first lens element of the plurality of lens elements closest to the object side and a first lens element of the plurality of lens elements closest to the image side is a non-biconvex lens.
2 . The photolithography projection lens as claimed in claim 1 , wherein a number of the plurality of lens elements is ten (10), and diopters of the ten (10) plurality of lens elements are positive, positive, positive, positive, negative, negative, negative, positive, positive, and positive, respectively from the image side to the object side in sequence, and wherein the light diaphragm is placed between a fifth lens element and a sixth lens element of the plurality of lens elements, and a first lens element to the fifth lens element of the plurality of lens elements have an overall focal length of 35 to 50 mm, and the sixth lens element to a tenth lens element of the plurality of lens elements have an overall focal length of 67 to 140 mm, and thereby a lens having a focal length>1000 mm and the magnification within the range of 0.25˜0.75× is generated.
3 . The photolithography projection lens as claimed in claim 1 , wherein a number of the plurality of lens elements is twelve (12), and diopters of the twelve (12) plurality of lens elements are positive, positive, negative, positive, positive, negative, negative, positive, positive, negative, positive, positive, respectively, from the image side to the object side in sequence, and wherein the light diaphragm is placed between a sixth lens element and a seventh lens element of the plurality of lens elements, and a first lens element of the plurality of lens elements to the sixth lens element of the plurality of lens elements have an overall focal length of 140 to 165 mm, and the seventh lens element of the plurality of lens elements to a twelfth lens element of the plurality of lens elements have an overall focal length of 72 to 82 mm, and thereby a lens having a focal length>1000 mm and the magnification within the range of 1.7˜2.3× is generated.
4 . The photolithography projection lens as claimed in claim 1 , wherein a number of the plurality of lens elements is thirteen (13), and diopters of the thirteen (13) plurality of lens elements are positive, positive, positive, negative, negative, negative, positive, positive, positive, negative, positive, positive, positive, respectively from the image side to the object side in sequence, and wherein the light diaphragm is placed between an eleventh lens element and a twelfth lens element of the plurality of lens elements, and a first lens element of the plurality of lens elements to the eleventh lens element of the plurality of lens elements have an overall focal length of 186 to 210 mm, and the twelfth lens element of the plurality of lens elements to a thirteenth lens element of the plurality of lens elements have an overall focal length of 76 to 85 mm, and thereby a lens having a focal length>1000 mm and the magnification within the range of 2.2˜2.7× is generated.
5 . The photolithography projection lens as claimed in claim 1 , further comprising: the prism set in front of the object side, and the each of the plurality of lens elements satisfy the refractive index of 1.45<Nd<1.75 and the numerical aperture between 0.08 and 0.21 to thereby generate a lens having a focal length >1000 mm.
6 . The photolithography projection lens as claimed in claim 1 , further comprising: the prism set in front of the object side, and the each of the plurality of lens elements satisfy the refractive index of 1.45<Nd<1.75 and the numerical aperture between 0.08 and 0.21 to thereby generate a lens having a focal length >500 mm.
7 . The photolithography projection lens as claimed in claim 5 , wherein a number of the plurality of lens elements is thirteen (13), and diopters of the thirteen (13) plurality of lens elements are positive, positive, negative, positive, positive, positive, negative, negative, positive, positive, negative, positive, positive, respectively from the image side to the object side in sequence.
8 . The photolithography projection lens as claimed in claim 6 , wherein a number of the plurality of lens elements is thirteen (13), and diopters of the thirteen (13) plurality of lens elements are positive, positive, positive, negative, negative, positive, positive, negative, positive, positive, negative, positive, positive, respectively from the image side to the object side in sequence.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photolithography projection lens, particularly to a non-mask photolithography imaging projection lens that images onto a substrate with unit magnification and high resolution. 2. Description of the Related Art The lithography process (photolithography) is an important step in the semiconductor unit manufacturing process. This step uses exposure and development to delineate the geometric pattern structure on the photoresist layer, and then transfers the pattern on the photomask to the substrate through the etching process; in other words, the lithography process is the process of “transferring” the circuit pattern to the wafer through the photomask and photoresist. Therefore, the lithography process requires very precise control over the shape and size of the image. The lithographic process for the manufacture of semiconductor components or similar products is usually using a projection exposure device to expose a pattern of a photomask and image it onto a photoresist-coated wafer (or glass plate or similar object); since the cramming of the elements of the semiconductor elements us increased, the projection lens in the projection exposure device is required to have the functions of unit magnification and high resolution. SUMMARY OF THE INVENTION A primary objective of the present invention is to provide a photolithography projection lens without mask, such as a digital micro-reflector (DMD) from Texas Instruments (TI), imaging onto a substrate with unit magnification and high resolution. Another objective of the present invention is to provide a photolithography projection lens that has a long working distance between substrates, and helps to control image aberrations and reduce manufacturing costs. To achieve the objects mentioned above, the present invention provide a photolithography projection lens which is a unit magnification lens system suitable for photoresist feature imaging comprises: a plurality of lens elements and a light diaphragm arranged among them, arranged along an optical axis, and comprising an object side and an image side respectively arranged at the front and rear ends of the plurality of lens elements; wherein: the diopters of the two lenses respectively near the object side and the image side must be positive; each of the lens elements is a single lens without cement; the angle between the chief rays at different image height positions and the optical axis is <1 degree, and the angle between the chief rays at different object height positions and the optical axis is <1 degree; and under the projection of 350˜450 nm wavelength light, it provide the imaging effect of precise magnification. The aforementioned “light diaphragm” component refers to a rectangular or circular aperture in the optical system that can limit the light beam; it is generally used to control the intensity of light, reduce aberration and increase the depth of focus; the smaller the aperture is and the smaller the aberration is, the greater the depth of field is and the sharper the image is, but the brightness is reduced. In addition, “single lens without cement” means all lenses are the single lens in the projection lens, and there is no doublet lens that uses adhesive to combine multiple lenses. Also, at least one of the first lens close to the object side and the first lens close to the image side is a non-biconvex lens. Also, further includes a prism set in front of the object side, and the negative lenses before and after the light diaphragm must satisfy the Abbe number of 30<Vd<50, and all lens elements must satisfy the refractive index of 1.45<Nd<1.75, and the aperture is between 0.08 and 0.21. Also, there are 10 lens elements, and their diopters are positive, positive, positive, positive, negative, negative, negative, positive, positive, positive from the image side to the object side in sequence, and the light diaphragm is placed between the fifth and the sixth lenses, the first to fifth lenses have an overall focal length of 35 to 50 mm, the sixth to tenth lenses have an overall focal length of 67 to 140 mm, and accordingly produce a lens with focal length>1000 mm and magnification of 0.25˜75×. Also, there are 12 lens elements, and their diopters are positive, positive, negative, positive, positive, negative, negative, positive, positive, negative, positive, positive from the image side to the object side in sequence, and the light diaphragm is placed between the sixth and the seventh lenses, the first to sixth lenses have an overall focal length of 140 to 165 mm, the seventh to twelfth lenses have an overall focal length of 72 to 82 mm, and accordingly produce a lens with focal length>1000 mm and magnification of 1.7˜2.3×. Also, there are 13 lens elements, and their diopters are positive, positive, positive, negative, negative, negative, positive, positive, positive, negative, positive, positive, positive from the im