Matrix technology of linear–angular measurements

Abstract

Subject of study. An important technological aspect of fabricating microelectronic elements is the design of high-precision methods for measuring linear and angular displacements. This study proposed a new technique for linear–angular measurements based on using a multi-element mark and obtaining measurement information about the angular and linear shift based on a set of measurements for all elements of the mark image. Method. The image of an optical mark, i.e., an ordered set of simple elements created using high-precision photolithography technology, was recorded using a photodetector matrix of a digital camera used as a metric space for measuring the coordinates of the mark image elements with their subsequent processing. Main results. The main aspects of the proposed measurement technique and the estimation of measurement errors are presented in this study. The results of simulating the measurement process of both linear and angular displacements were considered. The processing of the mark image and a set of computational procedures enabled the determination of both linear and angular displacements of the mark image with high accuracy (linear and angular displacements at the level of a few nanometers and hundredths of an arc second or less, respectively). The main directions for developing the proposed technique of matrix measurements were formulated. Among them, using digital liquid crystal displays to form a measuring mark and developing sensors using a shadow patterns (Fraunhofer diffraction) image of the mark are of particular interest. Practical significance. The proposed techniques for measuring linear and angular displacements can be successfully used to develop high-precision compact length and angle meters, linear–angle sensors, and technological modules for microelectronics in photomask fabrication.