CN103353669B - High numerical aperture immersion projection objective - Google Patents

The invention provides a high-numerical aperture immersion projection objective which is used for imaging an image of an object plane into an image plane; the immersion projection objective lens comprises a parallel flat plate group, a first lens group, a reflector group and a second lens group along the optical axis direction; the parallel flat plate group is provided with a parallel flat plate in sequence from the incident direction of the light beam, the first lens group has positive focal power, the reflector group has negative focal power, and the second lens group has positive focal power. The high-numerical-aperture immersion projection lens group can better compensate aberration, improve the imaging quality, improve the resolution of the objective lens and improve the photoetching efficiency.

一种高数值孔径浸没投影物镜A High Numerical Aperture Immersion Projection Objective

技术领域technical field

本发明涉及一种高数值孔径浸没投影物镜，尤其涉及一种高分辨力投影光刻物镜。The invention relates to a high numerical aperture immersion projection objective lens, in particular to a high resolution projection lithography objective lens.

背景技术Background technique

光学投影光刻是利用光学投影成像的原理，将掩模版上IC图形以分步重复或步进扫描曝光的方式将高分辨力图形转移到涂胶硅片上的光学曝光过程。光学投影光刻技术是在接触式和接近式光刻技术基础上发展起来的。采用投影光刻，可以延长掩模使用寿命，如果采用缩小倍率的投影物镜，还便于掩模制作。光学投影光刻经历了分步重复光刻(stepper)和步进扫描光刻(scanner)的发展过程。Optical projection lithography is an optical exposure process that uses the principle of optical projection imaging to transfer high-resolution patterns to rubber-coated silicon wafers by step-and-repeat or step-and-scan exposure of IC patterns on the mask. Optical projection lithography is developed on the basis of contact and proximity lithography. The use of projection lithography can prolong the service life of the mask, and if the projection objective lens with reduced magnification is used, it is also convenient for mask production. Optical projection lithography has experienced the development of stepper and scanner.

光刻分辨力可以通过缩短波长、降低工艺常数和提高投影光刻物镜的数值孔径来提高。实践证明，缩短曝光波长是最为有效的途径。光学投影光刻技术自1978年诞生以来，先后经历了436nm(g线)、365nm(i线)、248nm(KrF准分子激光)、193nm(ArF准分子激光)等几个技术阶段。除了缩短曝光波长外，不断减小工艺系数k1也是进一步提高分辨力的十分重要的因素。降低k1值的途径包括改善照明条件、提高抗蚀剂性能、采用光学邻近效应校正和相移掩模等几个方面。经过近10年的努力，已经使工艺系数因子k1值在大生产环境中从0.7减小到0.4。上述因素更佳的组合将使k1值减小到0.3乃至更小，这将成为今后一个时期光学光刻发展的一项战略措施。当k1＝0.25时，便接近光学光刻的物理极限。增大数值孔径也是提高光刻分辨力的重要途径，镜头的数值孔径已由最初的0.28、0.4、0.6逐渐增大到0.82，甚至0.85，几乎到了极限。在投影光刻法的情况下，像方数值孔径受像空间中的周围介质折射率的限制。在浸没光刻法中，理论上可能的数值孔径受浸没介质折射率的限制。但是，出于实际的考虑，数值孔径不应该任意地接近最后一个介质的折射率，因为传播角会因此变得相对于光轴非常大。业界已经证明，数值孔径基本不超过像方最后一个介质折射率的95％是可行的。这对应于相对光轴约72°的传播角。对于193nm的工作波长，这对应于在水(n＝1.43)作为浸没介质的情况下数值孔径为1.35。The lithography resolution can be improved by shortening the wavelength, reducing the process constant and increasing the numerical aperture of the projection lithography objective lens. Practice has proved that shortening the exposure wavelength is the most effective way. Since the optical projection lithography technology was born in 1978, it has gone through several technical stages such as 436nm (g-line), 365nm (i-line), 248nm (KrF excimer laser), 193nm (ArF excimer laser). In addition to shortening the exposure wavelength, continuously reducing the process coefficient k1 is also a very important factor to further improve the resolution. Ways to reduce the value of k1 include improving lighting conditions, improving resist performance, using optical proximity effect correction and phase shift masks, etc. After nearly 10 years of hard work, the process coefficient factor k1 has been reduced from 0.7 to 0.4 in a large production environment. A better combination of the above factors will reduce the value of k1 to 0.3 or even smaller, which will become a strategic measure for the development of optical lithography in the future. When k1=0.25, it is close to the physical limit of optical lithography. Increasing the numerical aperture is also an important way to improve the resolution of lithography. The numerical aperture of the lens has been gradually increased from the initial 0.28, 0.4, 0.6 to 0.82, or even 0.85, almost reaching the limit. In the case of projection lithography, the image-side numerical aperture is limited by the refractive index of the surrounding medium in image space. In immersion lithography, the theoretically possible numerical aperture is limited by the refractive index of the immersion medium. However, for practical reasons, the numerical aperture should not be arbitrarily close to the refractive index of the last medium, since the propagation angle would thus become very large with respect to the optical axis. The industry has proved that it is feasible that the numerical aperture basically does not exceed 95% of the refractive index of the last medium on the image side. This corresponds to a propagation angle of about 72° relative to the optical axis. For an operating wavelength of 193 nm, this corresponds to a numerical aperture of 1.35 with water (n=1.43) as immersion medium.

发明内容Contents of the invention

为了解决的现有技术的问题，本发明的目的是提供一种高数值孔径浸没投影物镜装置，提高投影物镜分辨力。本发明提出了适用一种深紫外照明，数值孔径达到1.35的投影光刻物镜，该物镜结构紧凑、大视场、成像质量优良，且具有适中的尺寸和材料消耗。In order to solve the problems of the prior art, the purpose of the present invention is to provide a high numerical aperture immersion projection objective lens device, which improves the resolution of the projection objective lens. The invention proposes a projection lithography objective lens suitable for deep ultraviolet illumination with a numerical aperture of 1.35. The objective lens has a compact structure, a large field of view, excellent imaging quality, and moderate size and material consumption.

为达成本发明的目的，本发明提供的一种高数值孔径浸没投影物镜的技术方案包括，从光束入射方向依次置有平行平板组、第一透镜组、反射镜组和第二透镜组；其中：平行平板组没有光焦度；第一透镜组是复杂化的双高斯结构，具有正光焦度，第一透镜组对物方图形成一次中间像，该中间像位于反射镜组的第一块反射镜之前；反射镜组具有负光焦度，并对物方图形成第二次中间像，用于校正所述物镜的场曲以及缩小其体积；第二透镜组具有正光焦度，将中间像成像在所述物镜的焦面处；物面发出的远心光束通过平行平板组，并入射到第一透镜组；平行平板组用作保护玻璃；第一透镜组具有双高斯结构，是对第一透镜组的输入光束进行成像，即形成第一次中间像，以便光束能顺利通过反射镜组的第二反射镜而不被遮挡；另一方面，第一透镜组对所述物镜产生的场曲，和反射镜组的第一反射镜，以及反射镜组的第二反射镜产生的场曲相补偿；反射镜组用于将输入光束实现两次反射折转，并在所述物镜中产生负的场曲用以实现补偿，从而减小所述物镜内的所有透镜的口径以及其几何尺寸；所述透镜组用于0.25倍率、1.35数值孔径的实现；最后，物面的光束通过平行平板组、第一透镜组、反射镜组和第二透镜组之后，再通过浸没液，在硅片面上形成物面的缩小像。In order to achieve the purpose of the present invention, the technical scheme of a kind of high numerical aperture immersion projection objective lens provided by the present invention comprises, is provided with parallel flat plate group, first lens group, reflecting mirror group and second lens group sequentially from the incident direction of light beam; Wherein : The parallel plate group has no power; the first lens group is a complex double Gaussian structure with positive power, and the first lens group forms an intermediate image on the object space image, which is located in the first block of the mirror group Before the reflecting mirror; the reflecting mirror group has a negative refractive power, and forms a second intermediate image on the object space map, which is used to correct the field curvature of the objective lens and reduce its volume; the second lens group has a positive refractive power, and the intermediate The image is formed at the focal plane of the objective lens; the telecentric light beam emitted by the object plane passes through the parallel plate group and is incident on the first lens group; the parallel plate group is used as a protective glass; the first lens group has a double Gauss structure, which is the The input light beam of the first lens group performs imaging, promptly forms the intermediate image for the first time, so that the light beam can pass through the second mirror of the mirror group without being blocked; field curvature, and the field curvature phase compensation produced by the first mirror of the mirror group and the second mirror of the mirror group; the mirror group is used to reflect and bend the input beam twice, and in the objective lens Negative field curvature is generated to achieve compensation, thereby reducing the aperture and geometric dimensions of all lenses in the objective lens; the lens group is used to achieve a magnification of 0.25 and a numerical aperture of 1.35; finally, the beam of the object plane passes through a parallel After the plate group, the first lens group, the mirror group and the second lens group, the immersion liquid is passed through to form a reduced image of the object plane on the silicon wafer surface.

本发明提供的一种使用所述的高数值孔径浸没投影物镜，用于深紫外照明光源。The invention provides a high numerical aperture immersion projection objective lens for deep ultraviolet illumination light source.

本发明与现有技术相比具有以下优点：Compared with the prior art, the present invention has the following advantages:

1、本发明所涉及的物镜分为四个部分即平行平板组、第一透镜组、反射镜组和第二透镜组，其中，第一透镜组、反射镜组、第二透镜组三个镜组的光焦度分别为正、负、正。这种结构能很好的校正物镜像差，特别是场曲，有利于提高成像质量，本发明所述物镜其波相差为1nm，畸变为1nm。1, the objective lens involved in the present invention is divided into four parts namely parallel plate group, the first lens group, reflecting mirror group and the second lens group, wherein, the first lens group, reflecting mirror group, the second lens group three mirrors The optical powers of the groups are positive, negative, and positive, respectively. This structure can well correct the objective mirror aberration, especially field curvature, and is beneficial to improve the imaging quality. The objective lens of the present invention has a wave aberration of 1nm and a distortion of 1nm.

2、本发明所涉及到的所述物镜由25片透镜和2片反射镜构成，所有透镜均使用同一种材料。所述物镜结构简单、紧凑，简化了物镜制作工艺，降低了制作成本，同时提高了物镜质量。2. The objective lens involved in the present invention is composed of 25 lenses and 2 reflecting mirrors, and all lenses use the same material. The objective lens has a simple and compact structure, simplifies the manufacturing process of the objective lens, reduces the manufacturing cost, and improves the quality of the objective lens at the same time.

3、本发明涉及到的物镜，其数值孔径很大，可达到1.35，如果改变高折射率的浸没液，可将数值孔径提高至1.5，工作波长在深紫外，物镜视场较大。因此本发明所涉及的物镜分辨力较高，光刻效率较高。3. The objective lens involved in the present invention has a very large numerical aperture, which can reach 1.35. If the immersion liquid with high refractive index is changed, the numerical aperture can be increased to 1.5. The working wavelength is deep ultraviolet, and the field of view of the objective lens is relatively large. Therefore, the object lens involved in the present invention has higher resolution and higher lithography efficiency.

4、本发明所涉及的物镜为双远心结构，物方远心度和像方远心度都较高，由于是双远心结构，因此即使掩模图形和硅片偏离与倾斜，也不会改变投影光刻的倍率。4. The objective lens involved in the present invention is a double-telecentric structure, and the object-side telecentricity and the image-side telecentricity are all high. Because it is a double-telecentric structure, even if the mask pattern and the silicon wafer deviate and tilt, it will not Will change the magnification of the projection lithography.

附图说明Description of drawings

图1为本发明的高数值孔径浸没投影物镜的结构示意图；Fig. 1 is the structural representation of the high numerical aperture immersion projection objective lens of the present invention;

图2为高数值孔径浸没投影物镜在全场范围内光学调制传递函数示意图；Fig. 2 is a schematic diagram of the optical modulation transfer function of the high numerical aperture immersion projection objective lens in the whole field;

图3a为高数值孔径浸没投影物镜场曲示意图。Fig. 3a is a schematic diagram of field curvature of a high numerical aperture immersion projection objective lens.

图3b为高数值孔径浸没投影物镜畸变示意图。Fig. 3b is a schematic diagram of distortion of a high numerical aperture immersion projection objective lens.

附图标号说明：Explanation of reference numbers:

1-第一平行平板、2-第一正透镜、3-第二正透镜、1-the first parallel plate, 2-the first positive lens, 3-the second positive lens,

4-第一弯月透镜、5-第三正透镜、6-第一负透镜、4-first meniscus lens, 5-third positive lens, 6-first negative lens,

7-第四正透镜、8-第五正透镜、9-第二弯月透镜、7-fourth positive lens, 8-fifth positive lens, 9-second meniscus lens,

10-第六正透镜、11-第三弯月透镜、12-第四弯月透镜、10-sixth positive lens, 11-third meniscus lens, 12-fourth meniscus lens,

13-第五弯月透镜、14-第七正透镜，15-第一反射镜、13-the fifth meniscus lens, 14-the seventh positive lens, 15-the first mirror,

16-第二反射镜、17-第六弯月透镜、18-第七弯月透镜、16-second reflector, 17-sixth meniscus lens, 18-seventh meniscus lens,

19-第二负透镜、20-第八正透镜、21-第九正透镜、19-second negative lens, 20-eighth positive lens, 21-ninth positive lens,

22-第十正透镜、23-第十一正透镜、24-第十二正透镜、22-tenth positive lens, 23-eleventh positive lens, 24-twelfth positive lens,

25-第十三正透镜、26-第十四正透镜、27-第十五正透镜、25-thirteenth positive lens, 26-fourteenth positive lens, 27-fifteenth positive lens,

28-像面。28-image surface.

具体实施方式Detailed ways

下面结合附图对本发明的具体实施方式作进一步详细地描述。The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings.

作为一种提高投影物镜分辨率的方案，本发明根据一种设计而提供一种适合于微光刻投影曝光机的投影物镜，其用于将该投影物镜的物面中提供的图案成像到该投影物镜的像平面上，该投影物镜包括：多个光学元件，这些光学元件对于该投影物镜的工作波长处的辐射是透明的。As a solution to improve the resolution of the projection objective lens, the present invention provides a projection objective lens suitable for a microlithography projection exposure machine according to a design, which is used to image the pattern provided in the object plane of the projection objective lens onto the On the image plane of the projection objective, the projection objective comprises a plurality of optical elements which are transparent to radiation at an operating wavelength of the projection objective.

作为浸没投影光刻物镜，其中的浸没液体厚度，优选在0.1mm和10mm之间，由于浸没液体常常表现为高吸收，因此在上述厚度范围内的较小厚度设计可能是有利的。As an immersion projection lithography objective, the thickness of the immersion liquid therein is preferably between 0.1 mm and 10 mm, since the immersion liquid often exhibits high absorption, a smaller thickness design in the above thickness range may be advantageous.

图1为本发明高数值孔径浸没投影光刻物镜布局示意图，共使用26片透镜和两片反射镜，从光束入射方向依次置有平行平板组G1、第一透镜组G2、反射镜组G3和第二透镜组G4；其中：平行平板组G1没有光焦度；第一透镜组G2是复杂化的双高斯结构，具有正光焦度，第一透镜组G2对物方图形成一次中间像，该中间像位于反射镜组G3的第一块反射镜15之前；反射镜组G3具有负光焦度，并对物方图形成第二次中间像，用于校正所述物镜的场曲以及缩小其体积；第二透镜组G4具有正光焦度，将中间像成像在所述物镜的焦面处；物面发出的远心光束通过平行平板组G1，并入射到第一透镜组G2；平行平板组G1用作保护玻璃；第一透镜组G2具有双高斯结构，是对第一透镜组G2的输入光束进行成像，即形成第一次中间像，以便光束能顺利通过反射镜组G3第二反射镜16而不被遮挡；另一方面，第一透镜组G2对所述物镜产生的场曲，和反射镜组G3的第一反射镜，以及反射镜组G3的第二反射镜产生的场曲相补偿；反射镜组用于将输入光束实现两次反射折转，并在所述物镜中产生负的场曲用以实现补偿，从而减小所述物镜内的所有透镜的口径以及其几何尺寸；所述透镜组用于0.25倍率、1.35数值孔径的实现；最后，物面的光束通过平行平板组G1、第一透镜组G2、反射镜组G3和第二透镜组G4之后，再通过浸没液，在硅片面上形成物面的缩小像。Fig. 1 is a schematic diagram of the layout of the high numerical aperture immersion projection lithography objective lens of the present invention. A total of 26 lenses and two reflectors are used, and a parallel plate group G1, a first lens group G2, a mirror group G3 and The second lens group G4; wherein: the parallel plate group G1 has no refractive power; the first lens group G2 is a complicated double Gaussian structure with positive refractive power, and the first lens group G2 forms an intermediate image on the object space diagram. The intermediate image is located in front of the first reflector 15 of the reflector group G3; the reflector group G3 has a negative power and forms a second intermediate image on the object space diagram, which is used to correct the field curvature of the objective lens and reduce its Volume; the second lens group G4 has a positive refractive power, and the intermediate image is imaged at the focal plane of the objective lens; the telecentric light beam emitted by the object plane passes through the parallel plate group G1 and enters the first lens group G2; the parallel plate group G1 is used as a protective glass; the first lens group G2 has a double Gaussian structure, which is used to image the input beam of the first lens group G2, that is, to form the first intermediate image, so that the beam can pass through the second mirror of the mirror group G3 smoothly 16 without being blocked; on the other hand, the field curvature produced by the first lens group G2 to the objective lens, and the field curvature phase produced by the first mirror of the mirror group G3 and the second mirror of the mirror group G3 Compensation; the mirror group is used to reflect and deflect the input beam twice, and generate a negative field curvature in the objective lens for compensation, thereby reducing the aperture and geometric size of all lenses in the objective lens; The lens group is used to realize the magnification of 0.25 and the numerical aperture of 1.35; finally, the light beam on the object plane passes through the parallel plate group G1, the first lens group G2, the mirror group G3 and the second lens group G4, and then passes through the immersion liquid, A reduced image of the object plane is formed on the silicon wafer.

平行平板组G1包括一块平行平板；The parallel plate group G1 includes a parallel plate;

第一透镜组G2包括第一正透镜2、第二正透镜3、第一弯月透镜4、第三正透镜5、第一负透镜(6)、第四正透镜7、第五正透镜8、第二弯月透镜9、第六正透镜10、第三弯月透镜11、第四弯月透镜12、第五弯月透镜13、第七正透镜14；在第一透镜组G2内，所述透镜独立安装，分别安装在各自的镜框内，所述透镜的镜框与所述物镜的整个镜筒相连。并且，所述透镜的机械位置通过修磨镜框的侧面厚度来实现。The first lens group G2 includes a first positive lens 2, a second positive lens 3, a first meniscus lens 4, a third positive lens 5, a first negative lens (6), a fourth positive lens 7, and a fifth positive lens 8 , the second meniscus lens 9, the sixth positive lens 10, the third meniscus lens 11, the fourth meniscus lens 12, the fifth meniscus lens 13, and the seventh positive lens 14; in the first lens group G2, all The above-mentioned lenses are installed independently, respectively installed in their respective frames, and the frames of the lenses are connected with the entire lens barrel of the objective lens. Moreover, the mechanical position of the lens is realized by grinding the side thickness of the mirror frame.

反射镜组G3包括第一反射镜15、第二反射镜16；第一反射镜15和第二反射镜16在同一光轴上，也就是说，第一反射镜15和第二反射镜16的顶点曲率半径球心的连线与所述物镜光轴重合；但是该高数值孔径浸没投影物镜只使用第一反射镜15和第二反射镜16的离轴部分，以便使得所述物镜不存在遮拦挡光；从第一透镜组G2出来的光束首先在第一反射镜15上反射，反射后的光束再经第二反射镜16反射，使得光束沿原来的方向行走。Mirror group G3 includes a first reflector 15 and a second reflector 16; the first reflector 15 and the second reflector 16 are on the same optical axis, that is to say, the first reflector 15 and the second reflector 16 The line connecting the center of the radius of curvature of the vertex coincides with the optical axis of the objective lens; but this high numerical aperture immersion projection objective only uses the off-axis portions of the first mirror 15 and the second mirror 16, so that there is no obscuration in the objective lens Light blocking: the light beam coming out of the first lens group G2 is firstly reflected on the first reflector 15, and the reflected light beam is then reflected by the second reflector 16, so that the light beam travels along the original direction.

第二透镜组G4包括第六弯月透镜17、第七弯月透镜18、第二负透镜19、第八正透镜20、第九正透镜21、第十正透镜22、第十一正透镜23、第十二正透镜24、第十三正透镜25、第十四正透镜26、第十五正透镜27，第十五正透镜27是平凸透镜，平凸透镜是所述物镜的最后一块透镜，且所述物镜的最后一面为平面；所述物镜的孔径光阑位于第十二正透镜24和第十三正透镜25之间；在透镜组G4内，各透镜独立安装，分别安装在各自的镜框内，所述透镜的镜框与所述物镜的整个镜筒相连。所述透镜的机械位置通过修磨镜框的侧面厚度来实现。第一透镜组G2具有正光焦度；反射镜组G3具有负光焦度；第二透镜组G4具有正光焦度。像面28是硅片所在表面。The second lens group G4 includes a sixth meniscus lens 17, a seventh meniscus lens 18, a second negative lens 19, an eighth positive lens 20, a ninth positive lens 21, a tenth positive lens 22, and an eleventh positive lens 23. , the twelfth positive lens 24, the thirteenth positive lens 25, the fourteenth positive lens 26, the fifteenth positive lens 27, the fifteenth positive lens 27 is a plano-convex lens, and the plano-convex lens is the last lens of the objective lens, And the last side of the objective lens is a plane; the aperture stop of the objective lens is located between the twelfth positive lens 24 and the thirteenth positive lens 25; in the lens group G4, each lens is installed independently, and is respectively installed in the respective In the frame, the frame of the lens is connected with the entire lens barrel of the objective lens. The mechanical position of the lens is achieved by grinding the side thickness of the frame. The first lens group G2 has a positive refractive power; the mirror group G3 has a negative refractive power; the second lens group G4 has a positive refractive power. The image plane 28 is the surface where the silicon chip is located.

所述平行平板组(G1)、第一透镜组(G2)、第二透镜组(G4)采用熔石英玻璃。所述熔石英玻璃的折射率是1.560326。The parallel plate group (G1), the first lens group (G2), and the second lens group (G4) use fused silica glass. The refractive index of the fused silica glass is 1.560326.

本发明还提供一种使用所述的高数值孔径浸没投影物镜，用于深紫外照明光源。The present invention also provides an immersion projection objective lens with high numerical aperture for deep ultraviolet illumination light source.

本发明的高数值孔径浸没投影物镜具有的27个元件且均处于同一光轴，利用透镜外框的机械组件固定它们之间的相对位置。本发明使用了熔石英(所述物镜中心波长时折射率为1.560326)作为透镜材料。The high numerical aperture immersion projection objective lens of the present invention has 27 elements, all of which are on the same optical axis, and the relative positions among them are fixed by the mechanical assembly of the lens outer frame. The present invention uses fused silica (the refractive index of the objective lens is 1.560326 at the central wavelength) as the lens material.

本发明的高数值孔径浸没投影光刻物镜的工作过程为：将物面即掩膜置于所述物镜的平行平板组G1前约43毫米处，各视场中心光线垂直入射平行平板组G1，光线依次经过第一透镜组G2、反射镜组G3、第二透镜组G4，最后将掩模所成的像缩小至四分之一成像在像面即硅片上。各视场中心光线垂直入射像面，该投影物镜为物方和像方双远心结构。The working process of the high numerical aperture immersion projection lithography objective lens of the present invention is as follows: the object plane, that is, the mask, is placed about 43 mm in front of the parallel plate group G1 of the objective lens, and the central rays of each field of view are vertically incident on the parallel plate group G1, The light rays pass through the first lens group G2, mirror group G3, and second lens group G4 in sequence, and finally the image formed by the mask is reduced to a quarter and imaged on the image plane, that is, the silicon wafer. The central light rays of each field of view are vertically incident on the image plane, and the projection objective lens has a double-telecentric structure on the object side and the image side.

为满足结构参数要求，并进一步提高像质，对物镜进行持续优化，经过优化后各个表面的半径、厚度、间隔，以及非球面系数发生变化，本实施例的具体优化措施为应用光学设计软件构造优化函数，并加入像差与结构限制参量，逐步优化为现有结果。In order to meet the requirements of structural parameters and further improve the image quality, the objective lens is continuously optimized. After optimization, the radius, thickness, interval, and aspheric coefficient of each surface change. The specific optimization measures in this embodiment are to apply optical design software to construct Optimize the function, and add aberration and structure limit parameters, and gradually optimize to the existing results.

本实施例通过以下技术措施实现：照明光源为ArF激光器，投影光刻物镜的数值孔径为1.35，畸变约为1nm，均方根波像差约为1nm，所述物镜缩小倍率为4倍。This embodiment is realized through the following technical measures: the illumination source is an ArF laser, the numerical aperture of the projection lithography objective lens is 1.35, the distortion is about 1nm, the root mean square wave aberration is about 1nm, and the magnification of the objective lens is 4 times.

下表中的“序号”是从光线入射端开始排列，如第一平行平板1的光束入射面为序号S1，光束出射面为序号S2，其它镜面序号号以此类推；“半径”分别给出每个波面所对应的球面半径，对于非球面而言，是其定点球面半径；“间距”给出相邻两个表面之间沿光轴的中心距离，如果两个表面属于同一块镜片，则间距表示该镜片的厚度。透镜组的具体参数如下：The "serial numbers" in the table below are arranged from the light incident end, for example, the beam incident surface of the first parallel plate 1 is the serial number S1, the beam exit surface is the serial number S2, and the serial numbers of other mirror surfaces are deduced by analogy; "radius" are respectively given The spherical radius corresponding to each wave surface is its fixed-point spherical radius for an aspheric surface; "Space" gives the center distance between two adjacent surfaces along the optical axis. If the two surfaces belong to the same lens, then The pitch indicates the thickness of the lens. The specific parameters of the lens group are as follows:

序号serial number 半径radius 间距spacing 材料Material 物面Object surface ∞∞ 43.2043.20 S1S1 ∞∞ 19.0719.07 SiO₂ SiO ₂ S2S2 ∞∞ 1.351.35 S3S3 341.90341.90 31.7031.70 SiO₂ SiO ₂ S4(ASP)S4 (ASP) -1470.50-1470.50 3.343.34 S5S5 176.72176.72 59.8559.85 SiO₂ SiO ₂ S6(ASP)S6 (ASP) -625.99-625.99 3.873.87 S7(ASP)S7(ASP) -440.58-440.58 19.4019.40 SiO₂ SiO ₂ S8S8 -684.29-684.29 1.001.00 S9S9 1962.021962.02 22.5822.58 SiO₂ SiO ₂ S10(ASP)S10 (ASP) -488.85-488.85 7.117.11 S11S11 -266.59-266.59 17.2817.28 SiO₂ SiO ₂ S12(ASP)S12 (ASP) 186.97186.97 4.454.45 S13S13 228.14228.14 46.7346.73 SiO₂ SiO ₂ S14(ASP)S14 (ASP) -269.23-269.23 1.001.00 S15S15 93.6593.65 32.1332.13 SiO₂ SiO ₂ S16(ASP)S16 (ASP) 558.93558.93 15.0015.00 S17S17 -172.37-172.37 18.9318.93 SiO₂ SiO ₂ S18(ASP)S18 (ASP) -242.70-242.70 2.142.14 S19S19 560.38560.38 29.7629.76 SiO₂ SiO ₂ S20(ASP)S20 (ASP) -134.23-134.23 1.411.41 S21(ASP)S21 (ASP) -184.97-184.97 24.6124.61 SiO₂ SiO ₂ S22S22 -186.36-186.36 15.0215.02 S23(ASP)S23 (ASP) -95.37-95.37 24.3724.37 SiO₂ SiO ₂ S24S24 -119.79-119.79 22.7222.72 S25(ASP)S25 (ASP) -76.53-76.53 38.9238.92 SiO₂ SiO ₂ S26S26 -138.07-138.07 15.3815.38 S27(ASP)S27 (ASP) -307.87-307.87 68.5368.53 SiO₂ SiO ₂

S28S28 -139.86-139.86 323.17323.17 S29(ASP)S29 (ASP) -246.04-246.04 -266.51-266.51 Mirrormirror S30(ASP)S30 (ASP) 198.05198.05 317.63317.63 Mirrormirror S31S31 328.75328.75 18.3618.36 SiO₂ SiO ₂ S32(ASP)S32 (ASP) 370.51370.51 30.5230.52 S33S33 213.13213.13 27.6527.65 SiO₂ SiO ₂ S34(ASP)S34 (ASP) 116.14116.14 48.1248.12 S35S35 -2580.84-2580.84 29.8129.81 SiO₂ SiO ₂ S36(ASP)S36 (ASP) 224.87224.87 27.2627.26 S37S37 -3509.94-3509.94 49.6049.60 SiO₂ SiO ₂ S38S38 -289.19-289.19 1.001.00 STOSTO -1199.37-1199.37 52.1052.10 SiO₂ SiO ₂ S40S40 -355.51-355.51 1.001.00 S41S41 -3138.22-3138.22 35.4035.40 SiO₂ SiO ₂ S42S42 -1158.92-1158.92 9.599.59 S43S43 -688.99-688.99 79.5579.55 SiO₂ SiO ₂ S44(ASP)S44 (ASP) -264.45-264.45 1.001.00 S45S45 265.30265.30 89.6289.62 SiO₂ SiO ₂ S46S46 -15405.57-15405.57 1.001.00 Stopstop 0.000.00 1.001.00 S48S48 197.15197.15 49.4049.40 SiO₂ SiO ₂ S49(ASP)S49 (ASP) 240.42240.42 1.001.00 S50S50 133.74133.74 74.2574.25 SiO₂ SiO ₂ S51(ASP)S51 (ASP) 543.90543.90 1.001.00 S52S52 59.4759.47 60.7660.76 SiO₂ SiO ₂ S53S53 ∞∞ 2.002.00 像面Image surface ∞∞ 00

系数coefficient S32S32 KK 00 C1C1 -3.25206E-08-3.25206E-08 C2C2 3.86752E-123.86752E-12 C3C3 4.36996E-164.36996E-16 C4C4 -1.67093E-19-1.67093E-19 C5C5 2.93919E-232.93919E-23 C6C6 -3.26387E-27-3.26387E-27 C7C7 2.31398E-312.31398E-31 C8C8 -9.47297E-36-9.47297E-36 C9C9 1.70693E-401.70693E-40

以上各元件的具体参数在实际操作中，可做调整以满足不同的系统参数要求。The specific parameters of the above components can be adjusted in actual operation to meet different system parameter requirements.

对本实施例制作的深紫外高数值孔径浸没光刻物镜采用以下三种评价手段进行测评：The following three evaluation methods were used to evaluate the deep ultraviolet high numerical aperture immersion lithography objective lens produced in this embodiment:

1、光学调制传递函数评价1. Evaluation of optical modulation transfer function

图2为高数值孔径浸没投影物镜在全场范围内光学调制传递函数示意图，光学调制传递函数(MTF)是确定物镜分辨力和焦深的直接评价。图示横坐标是空间频率，单位是线对/毫米，纵坐标是调制函数，所述物镜MTF已经达到衍射极限。如图2所示的本实施例所述的深紫外高数值孔径浸没光刻物镜在全场范围内光学调制传递函数(MTF)图表明，MTF≈40％时，所述物镜分辨率达到7000线对/毫米，截止频率为13760线对/毫米。Figure 2 is a schematic diagram of the optical modulation transfer function of a high numerical aperture immersion projection objective lens in the full field range. The optical modulation transfer function (MTF) is a direct evaluation to determine the resolution and depth of focus of the objective lens. The abscissa in the figure is the spatial frequency, the unit is line pair/mm, and the ordinate is the modulation function, and the MTF of the objective lens has reached the diffraction limit. As shown in Figure 2, the optical modulation transfer function (MTF) diagram of the deep ultraviolet high numerical aperture immersion lithography objective lens described in this embodiment in the whole field shows that when MTF≈40%, the resolution of the objective lens reaches 7000 lines Pairs/mm, the cutoff frequency is 13760 Pairs/mm.

2、像散和场曲与畸变2. Astigmatism, field curvature and distortion

图3a为投影光刻物镜场曲意图，横坐标是离焦量，单位是毫米，纵坐标是物高；图3b为投影光刻物镜畸变示意图，横坐标畸变百分比，纵坐标是物高。从图中可以看出，所述物镜焦面偏移在弧矢与子午面上都小于0.2μm，用最大偏离值和最小偏离值的差来表示总偏离，即Ftot＝Fmax-Fmin(即，焦面偏移＝视场最大偏移量-视场最小偏移量)，其最大值Ftot＝80nm。畸变随视场变化，边缘畸变最大处为4.2e-8，故全视场最大畸变小于1nm。Figure 3a is the field curve diagram of the projection lithography objective lens, the abscissa is the defocus amount in millimeters, and the ordinate is the object height; Figure 3b is a schematic diagram of the distortion of the projection lithography objective lens, the abscissa is the percentage of distortion, and the ordinate is the object height. As can be seen from the figure, the focal plane offset of the objective lens is all less than 0.2 μm on the sagittal and meridional planes, and the total deviation is represented by the difference between the maximum deviation value and the minimum deviation value, that is, Ftot=Fmax-Fmin (that is, Focal plane offset = maximum offset of field of view - minimum offset of field of view), and its maximum value Ftot = 80nm. The distortion varies with the field of view, and the maximum edge distortion is 4.2e-8, so the maximum distortion of the entire field of view is less than 1nm.

3、均方根波像差3. RMS wave aberration

本实施例所设计的光刻物镜，以质心为参考的单色均方根波像差的最小值为0.0053(F0.57，即0.57视场处)为1nm，最大值为0.0083λ(F0.79)为1.6nm，λ为波长。The lithography objective lens designed in this embodiment has a minimum value of 0.0053 (F0.57, i.e. 0.57 field of view) of the monochromatic RMS wave aberration with the center of mass as a reference, and a maximum value of 0.0083λ (F0.79) is 1.6nm, and λ is the wavelength.

本发明通过增加镜片，选择部分非球面球面透镜，优化各个透镜的半径、厚度，以及非球面系数等参数，得到了像质优良，易于制造的新物镜。所述物镜结构紧凑，为双远心结构且远心度高，像质优良。The invention obtains a new objective lens with excellent image quality and easy manufacture by adding lenses, selecting some aspheric spherical lenses, and optimizing parameters such as radius, thickness, and aspheric coefficient of each lens. The objective lens has a compact structure, a double telecentric structure, high telecentricity, and excellent image quality.

本技术领域中的普通技术人员应当认识到，以上的实施例仅是用来说明本发明，而并非用作为对本发明的限定，只要在本发明的实质精神范围内，对以上所述实施例变化，变型都将落在本发明权利要求书的范围内。Those of ordinary skill in the art should recognize that the above embodiments are only used to illustrate the present invention, rather than as a limitation to the present invention, as long as within the scope of the spirit of the present invention, changes to the above embodiments , modifications will fall within the scope of the claims of the present invention.