测量表面倾角对差动共焦瞄准信号影响分析

普通共焦显微镜的轴向响应特性,因受到被测量表面的倾斜角影响引从而起轴向响应特性变化,而应用差动共焦光学系统对超精密加工的表面进行瞄准测量时,差动系统的瞄准信号也受到影响,并进而影响到测量系统对加工表面的测量精度及分辨特性。通过对差动共焦测量系统输出信号理论模型的分析得出被测量面的倾斜角变化不影响差动共焦输出信号零点位置;倾角在一定范围内变化时不影响瞄准测量分辨力的结论,并给出了实验分析结果。     

光栅尺测长式激光差动共焦曲率半径测量系统

为了增强高精度曲率半径测量仪器的抗环境干扰能力,满足现场使用需求,研制了一套基于光栅尺测长的激光差动共焦曲率半径测量系统。该系统利用差动共焦轴向光强响应曲线的过零点对应系统物镜聚焦焦点这一特性,对被测样品的猫眼位置及共焦位置进行精确瞄准定位,并借助光栅尺测长得到透镜猫眼位置与共焦位置之间的距离,实现曲率半径的测量。实验表明,该系统相对测量精度优于510-6,满足高精度曲率半径测量的精度需求。     

应用共焦显微镜原理测量倾斜工程表面

用基尔霍夫衍射公式分析反射式共焦光路 ,得到了被测件有一定倾斜角度表面的共焦轴向响应理论模型。由菲涅耳衍射近似公式得到的共焦轴向响应特性只是它的理论模型的一个特例。同时 ,对接收端采用差动连接的共焦测量的聚焦瞄准信号进行了分析 ,得到了表面倾斜角对聚焦瞄准信号影响的关系。应用共焦实验系统及差动测量系统对具有不同倾角的块规斜面的轴向响应信号进行了测量。理论模型的数值分析与实验结果相吻合。用差动共焦光学系统作为瞄准传感器、用电容传感器进行位移监测 ,对倾角为 10°的角规的斜面进行测量 ,得到分辨率小于 2 0nm的表面形貌图。     

激光共焦球面元件姿态自动调整系统

为解决激光差动共焦元件参数测量系统中人工调整元件姿态效率低、重复性差的问题，研制了激光共焦球面元件姿态自动调整系统。基于共焦原理，建立了元件失调量与电动四维调整机构调整量关系的数学模型，并根据CCD探测器实时获取的光斑位置信号分析出被测件的姿态信息，结合闭环反馈控制算法实现姿态自动调整。利用电动四维调整机构搭建了自动调整实验装置，实验结果表明:研制的电动调整机构平移调整分辨力达到0.5 μm，倾斜调整分辨力达到8″；调整系统能够快速、稳定地将被测件姿态失调量调至误差范围内，有效提高调整重复性及效率，对激光差动共焦测量系统实现全自动球面元件参数检测格外重要。     

激光差动共焦曲率半径测量不确定度评定

曲率半径是球面光学元件中的重要参数之一,曲率半径的高精度测量已经成为光学元件使用与加工中的一个关键问题。提出了基于差动共焦法的曲率半径测量方法,研制了1套激光差动共焦曲率半径测量系统,并对2组曲率半径测量结果进行不确定度评定。结果表明,2组曲率半径的测量值均与标称值吻合,其相对误差为0001 15%,两组测量数据的标准不确定度均优于3211 11×10-4 mm。     

激光差动共焦曲率半径测量不确定度评定

曲率半径是球面光学元件中的重要参数之一,曲率半径的高精度测量已经成为光学元件使用与加工中的一个关键问题。提出了基于差动共焦法的曲率半径测量方法,研制了1套激光差动共焦曲率半径测量系统,并对2组曲率半径测量结果进行不确定度评定。结果表明,2组曲率半径的测量值均与标称值吻合,其相对误差为0.001 15%,两组测量数据的标准不确定度均优于3.211 1110-4 mm。     

具有高空间分辨力的整形环形光式差动共焦测量法

提出一种新的具有高空间分辨力的整形环形光式差动共焦测量方法。该方法通过整形环形光式共焦测量法和锐化爱里斑主瓣，改善系统横向分辨力；通过差动共焦测量法改善系统的轴向分辨力，最终达到提高系统空间分辨能力的目的。理论分析和实验表明：整形环形光内孔归一化半径ε越大，横向分辨力改善越明显，量程扩展范围越宽；当入射光波长λ=632.8nm，物镜数值孔径取NA=0.85，ε=0.5时，该系统的横向分辨力优于0.2μm，轴向分辨力优于2nm。该方法为光触针测量系统空间分辨力的提高提供了1种新的方法，可广泛应用于超精密三维微细结构工件的超精密测量。     

光学仪器 眼镜、放大镜、显微镜、望远镜

TH742.9 2005021541 扩展差动共焦显微系统量程范围的方法与措施=An ap- proach to expansion measurement range of heterodyne con- focal microscopy system[刊,中]／赵维谦(哈尔滨工业大学 超精密光电仪器工程研究所．黑龙江,哈尔滨(150001)), 邱丽荣…//光电子·激光．-2004,15(9)．-1083-1087 为扩展差动共焦显微镜(HCMS)的测量量程范围,使 其满足三维微细结构和三维表面轮廓测量时的需求,基于     

激光差动共焦拉曼光谱高分辨图谱成像技术进展

激光共焦拉曼光谱技术由于具有分子指纹及层析成像特性,成为探索微观分子世界的重要手段;但受原理限制,现有激光共焦拉曼光谱技术的分辨力及图谱成像能力逐渐桎梏了其发展。近年来,围绕激光共焦拉曼光谱技术性能改善方面,本研究团队基于发明的超分辨激光差动共焦技术,提出了激光差动共焦拉曼图谱成像系列新方法和新技术。系统地介绍所提激光差动共焦拉曼图谱系列测量方法及仪器化研究进展,并对未来发展方向进行了评述和展望。     

基于虚拟双差动共焦的快速表面轮廓测量方法

针对传统共焦显微技术定焦过程中扫描速度和扫描精度无法兼顾的问题,提出了一种基于虚拟双差动共焦的快速表面轮廓测量方法。其将传统共焦响应曲线向前平移和向后平移指定量得到虚拟前焦和虚拟后焦信号;然后将虚拟前、后焦信号与原始共焦信号分别相减,并将相减结果做相加处理得到虚拟双差动曲线。虚拟双差动曲线具有大线性范围、高定焦灵敏度的特点,在大扫描间距情况下获取表面轮廓时,可实现样品表面轮廓的快速、高精度的定焦。仿真分析及实验结果表明,与传统差动共焦显微成像方法相比,虚拟双差动共焦表面轮廓测量方法可在保持高定焦精度的前提下,将几何形貌成像速度提高2倍以上。     

An optical system incorporating gradient-index lens for confocal inspection

A differential confocal measurement system features high lateral resolution and depth-discriminated sections. In comparison with conventional lens, gradient-index lens is lighter in weight, smaller in volume and easy to couple. In order to facilitate the measurement of a small irregular surface in a limited space, a small optical inspection system is presented, which combines the high axial resolution and absolute position tracking capability of a differential confocal microscopy and the compact design of gradient-index lens, and uses gradient-index lens to obtain a small detector of 1 mm in diameter. The operating principle and construction of the measurement system are detailed. The differential design of the two detectors eliminates both the fluctuation of light source and the electronic noise from probes, and increases the axial resolution as well.     

微型差动式共焦自聚焦光聚焦探测系统

为解决微小内轮廓尺寸为代表的微小尺寸的非接触式超精密测量问题，提出了将自聚焦透镜体积小的特点与共焦显微技术的高分辨率和绝对位置跟踪特性相结合的差动式自聚焦共焦微型显微技术的光探测技术，建立了相应的传感系统，介绍了系统的工作原理和构成，自聚焦透镜测头直径为1mm，两个探测器差动设置，不但消除了光源的光强漂移和探测器的电子漂移产生的共模噪声，提高了测量信噪比，而且有效地提高了系统的轴向分辨率，初步实验表明，系统轴向分辨率在倾斜率小于20度的范围内可达5nm。     

Differential confocal technology based on radial birefringent pupil filtering principle

In order to improve the spatial resolution of a confocal system, a radial birefringent pupil filter (RBPF) is introduced into a differential confocal system. RBPF consists of two polarizers with a birefringent element between them, and its pupil function is deduced from Jones matrix. The thickness and curvature radius of RBPF are optimized independently, using the first zero coordinate ratio. The pupil function is modulated by RBPF to enhance the half-width of the response function, and lateral resolution is improved when response curve is changed with the position of RBPF as well as the polarization; then axial super-resolution of the system can be guaranteed using differential confocal detection mechanism. In comparison with conventional pupil filtering technology, RBPF features high lateral resolution and can be easily produced; moreover, it also has a simple structure. Together with its low cost, RBPF provides a new way for the improvement of super-resolution of confocal system. It is indicated from theoretical analysis and preliminary experiments that the lateral resolution can be significantly improved and the measurement error is reduced by 76 nm when measuring a standard grating of period 3 μm; the axial resolution up to 3 nm has been achieved using the optimized pupil filter. In addition to its application for measurement of a small irregular surface in a limited space, the whole differential confocal system proposed can be fitted onto a coordinate measuring machine for non-contact measurement of dimensions and surface roughness.     

Dual-axes differential confocal microscopy with high axial resolution and long working distance

We discover that the slight transverse offset of a point detector results in a shift of the axial intensity response curve in a dual-axes confocal microscopy (DCM). Based on this, we propose a new dual-axes differential confocal microscopy (DDCM) with high axial resolution and long working distance, in which two point detectors are placed symmetrically about the collection axis. And a signal is obtained through the differential subtraction of two signals received simultaneously by the two point detectors. Theoretical analyses and preliminary experiments indicate that DDCM is feasible and suitable for the high precision tracing measurement of microstructures and surface contours.     

微分干涉差共焦显微膜层微结构缺陷探测系统

多层膜极紫外光刻掩模"白板"缺陷是制约下一代光刻技术发展的瓶颈之一,为提高对掩模"白板"上的膜层微结构缺陷的分辨能力,提出了一种微分干涉差共焦显微探测系统方案。基于标量衍射理论,计算了系统横向和轴向分辨率。利用MATLAB建模仿真,在数值孔径为0.65、工作波长为405 nm时,分析比较了微分干涉差共焦显微系统、传统显微系统和共焦显微系统的分辨率。结果表明微分干涉差共焦显微系统具有230 nm的横向分辨率和25 nm轴向台阶高度差的分辨能力(对应划痕等缺陷形式)。此外,仿真和分析了实际应用中探测器尺寸、样品轴向偏移等的影响,模拟分析了膜层微结构缺陷的探测,结果表明本系统可以探测200 nm宽、10 nm高的微结构缺陷,较另外两种系统有更好的探测能力。     

光纤共焦扫描显微术用于光盘盘基预刻槽结构的检测

基于共焦扫描差分术,提出了检测不同表面反射率的物体表面表貌的方法,并提出了在光纤共焦扫描成像术中利用边缘判据进行边缘定位的极限尺度。上述思想用于检测光盘盘基预刻槽形结构,在建立的一套光纤共焦扫描成像装置上进行了光盘盘基预刻槽结构的检测,获得了槽宽、槽间距及槽深等实验数据,与槽标准参数相符。     

A lateral super-resolution differential confocal technology with phase-only pupil filter

In order to achieve a higher lateral resolution required for ultraprecision measurement of microstructural workpieces, phase-only pupil filtering differential confocal microscopy (PFDCM), a new approach is proposed based on the differential confocal microscopy (DCM), which uses a three-zone phase-only pupil filter with lateral super-resolution capability obtained through optimized design to change the distribution of DCM three-dimensional point spread function, so that the DCM lateral resolution is therefore significantly improved while its axial resolution is slightly improved. Preliminary experimental comparison and analyses indicate that, the lateral and axial resolutions of PFDCM are better than 0.2 μm and 2 nm, respectively, when wavelength of incidence laser beam , numerical aperture of measuring lens NA=0.85, and lateral spot size with a three-zone phase-only pupil filter G_T=0.65. It is therefore concluded that PFDCM is a new approach to further improvement of lateral resolution in laser probe measurement systems.