基于表面等离子体的超分辨光刻理论与实验研究

发布时间：2018-05-09 09:36

本文选题：表面等离子体 + 超分辨　；参考：《电子科技大学》2017年博士论文

【摘要】：光刻技术是集成电路的一个关键技术,其主要目的是将掩模板上的图形复制到硅片上。整个芯片工艺所能达到的最小尺寸就是由光刻技术决定的。由于受光学衍射极限的约束,传统光刻的分辨力只能达到半个波长水平。通常情况下,人们通过减小工作波长或者提高数值孔径的方法提高光刻图形的分辨力。但面临着波长持续缩短和数值孔径极限的成本和技术障碍。分辨力受限的本质在于携带物体精细结构信息的高频倏逝波传播距离短,不能传输至像面参与成像所致。近年来,近场光学的迅速发展,使得对倏逝波的操控和调节成为可能,以表面等离子体(surface plasmons,SPs)为代表的突破衍射极限的方法受到了广泛关注。本论文主要是利用SPs调控光波信息的传输,开展基于SPs的超分辨光刻理论和实验研究。主要内容可分为三个部分:利用金属/介质多层膜超材料传输衍射受限的图形信息实现一对一的超分辨光刻成像;利用超材料的滤波传输特性使得单一衍射级次的高频倏逝波通过,并相互干涉产生深亚波长的光刻图形;分析膜层表面粗糙度对纳米尺度光刻图形质量的影响。具体研究内容和结果为:1.基于SPs的超分辨成像光刻研究。一方面,实验验证了多层膜结构可以有效传输倏逝波提高光刻分辨力的理论。利用平面型金属/介质复合纳米薄膜设计出可以传输物体精细结构信息的超材料,通过共溅射方法制备复合多层膜,最终实验获得了特征尺寸100 nm的亚波长掩模的光刻图像。另一方面,针对一对一成像形式的超分辨光刻中掩模图形特征尺寸难以持续减小的问题,提出了一种超分辨缩小成像光刻结构。主要是以金属/介质多层膜超材料为基础,设计出曲面-平面混合膜层结构的光刻结构,模拟结果表明任意间隔的缝隙的特征尺寸从100 nm可被缩小至28 nm(3.5倍缩小)。这种方法利用大特征尺寸的掩模获得小特征尺寸的图形,避免了小特征尺寸的掩模加工难题。2.基于SPs的超分辨干涉光刻研究。限于表面传输的SPs可干涉形成周期图形,但存在干涉区域面积小、光场不均匀、掩模加工复杂的问题,本文提出并实验验证了一种基于新型多层膜超材料的体等离子体(bulk plasmons,BPs)干涉光刻结构。主要是利用金属/介质多层膜构造新型的等离子体超材料,它具有较窄的波矢量传输通带窗口,可以选择传输特定级次的衍射波,并在光刻胶层形成大面积的均匀深亚波长干涉光刻图形。作为示例,我们利用制备的超平埋入式掩模和多层膜超材料选择传输双束、四束BPs波,在光刻胶层干涉获得均匀的半周期45 nm(~λ/8)的一维、二维光刻图形。而且,进一步计算表明,通过调节多层膜的几何参数还可以获得更小分辨力至22.5 nm(~λ/16)的周期图形,以及六束BPs干涉的蜂巢状图形。另外,借鉴传统多波束干涉原理,我们系统研究了利用多束BPs干涉获得超衍射的多样化图形方法,推导出各干涉周期图形的周期计算公式,完善了近场表面波干涉理论。这部分工作在纳米光刻方面,提供了一种具有经济、可并行、大面积、图形均匀等优势的加工方法。3.纳米膜层粗糙度检测及其对光刻图形质量的影响分析。一方面,针对常用的银/胶/银三层膜构成的SPs共振腔成像光刻结构,结合模板剥离技术,检测了金属透射膜层的上、下表面粗糙度。并从薄膜的生长模式方面分析了不同衬底材料对生长薄膜的表面粗糙度影响。另一方面,针对以单层膜超透镜和多层膜超材料为基础的两种SPs超分辨光刻结构,比较分析了膜层粗糙度对光刻图形质量的影响,包括光刻图形的边缘粗糙度、光强度等关键参量。并从光学传递函数和SPs传输模式等方面解释了膜层和掩模缺陷在两种光刻结构中造成不同效果的原因,阐述了具有空间频率选择特性的光刻结构对膜层缺陷容忍度较高的特点,并利用SPs波导光刻结构验证了分析结果。这部分研究对纳米薄膜的性能分析,及光刻结构设计具有较高的参考意义。
[Abstract]:Photolithography is a key technology in integrated circuits. Its main purpose is to copy the graphics on the mask to silicon. The minimum size of the whole chip process is determined by photolithography. Due to the constraints of the optical diffraction limit, the resolution of the traditional lithography can only reach a half wavelength level. By reducing the working wavelength or increasing the numerical aperture, the resolution of the photolithography is improved. However, it is faced with the cost and technical barrier to the continuous shortening of the wavelength and the limit of the numerical aperture. The nature of the resolution limitation is that the high frequency evanescent wave propagation distance that carries the fine structure information of the object is short and can not be transferred to the image surface to participate in the imaging. In recent years, the rapid development of near field optics makes it possible to manipulate and regulate evanescent waves. The method of breaking the diffraction limit represented by surface plasma (surface plasmons, SPs) has attracted wide attention. This paper mainly uses SPs to regulate the transmission of light wave information, and carries out the theory and experiment of ultra resolution lithography based on SPs. The main content can be divided into three parts: one to one super-resolution lithography is realized by using metal / dielectric multilayer supermaterial to transmit diffraction limited graphic information. The high frequency evanescent wave of single diffraction order is passed through the filtering transmission characteristics of supermaterial, and the photolithography of deep sub wavelength is involved in each other, and the analysis of the film is analyzed. The effect of surface roughness on the quality of nanoscale lithography. The specific research content and results are 1. based on SPs based superresolution imaging photolithography. On one hand, the experiment verifies the theory that multilayer membrane structures can effectively transmit evanescent waves to improve the photolithography resolution. The supermaterial with fine structure information is prepared by CO sputtering method. Finally, the photolithography images of the sub wavelength mask with characteristic size of 100 nm are obtained. On the other hand, a super resolution narrowing imaging is proposed for the problem that the mask pattern feature size is difficult to decrease continuously in the one to one imaging super resolution lithography. Photolithography structure, mainly based on metal / dielectric multilayer supermaterials, is designed to design a photolithography structure of a surface - plane - plane mixed membrane structure. The simulation results show that the feature size of the gap at any interval can be reduced from 100 nm to 28 nm (3.5 times smaller). .2. based on SPs based superresolution interference photolithography for small feature size, the SPs can interfere with the formation of periodic patterns, but the area of the interference region is small, the light field is not uniform, and the mask processing is complex. In this paper, a new type of bulk plasma (bulk) based on a new type of multilayer supermaterial (bulk) is presented and verified experimentally. Plasmons, BPs) interference lithography structure. It is mainly to use metal / dielectric multilayer to construct a new type of plasma supermaterial. It has a narrow wave vector transmission band window. It can choose the diffraction wave of a particular order, and form a large area of uniform deep subwavelength interference lithography in the photolithography. As an example, we use the preparation The ultra flat embedded masks and multilayer film supermaterials choose to transfer double beams and four beam BPs waves to obtain a uniform half period of 45 nm (~ /8) in the photolithography. Moreover, further calculations show that the periodic patterns of smaller resolution to 22.5 nm (~ [/16) can be obtained by adjusting the geometric parameters of the multilayer film, and Six beehive shapes of BPs interference. In addition, drawing on the traditional multi beam interference principle, we systematically studied the multi beam BPs interference to obtain the diversification of the ultra diffraction pattern, derived the periodic calculation formula of each interference periodic figure, and improved the near field surface wave interference theory. This part of the work provides a kind of nano lithography. The.3. nano film roughness detection and its influence on the photolithography quality are analyzed with the advantages of economic, parallel, large area, and uniform graphics. On the one hand, the SPs resonant cavity imaging lithography structure composed of the three layers of silver / glue / silver film is used to detect the upper and lower surface roughness of the metal transmission film with the template stripping technique. The influence of different substrate materials on the surface roughness of the growth film is analyzed from the growth mode of the film. On the other hand, the influence of the coating roughness on the photolithography quality is compared and analyzed for the two SPs super-resolution lithography structures based on the single layer superlensing and the multilayer supermaterial, including the edge of the lithography pattern. The factors such as roughness, light intensity and other key parameters are explained in terms of the optical transfer function and the SPs transmission mode. The reasons for the different effects of the film and mask defects in the two lithography structures are explained. The characteristics of the photolithography structure with the characteristics of the spatial frequency selection are described, and the structure of the SPs waveguide photolithography is verified. The analysis results are of great reference value to the performance analysis of nano thin films and the design of lithography structure.

【学位授予单位】：电子科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TN305.7

【参考文献】