원자현미경을 이용한 나노구조체의 각도측정 방법 및 조건

Angle Measurement Methods and Conditions Using AFM

Invention of the atomic force microscopy (AFM) has provided a powerful measurement capability for sub-nano scale science and technology. Since invention, AFM has been significantly improved, and numerous innovative mechanisms and measuring modes have been developed. As the progress of miniaturization in patterns and photoresist structures in semiconductor, microelectronics, and glass industry, along with the fast advance of the extremely versatile nanotechnology applications, in a great number of industrial processes calls for reliable and comparable quantitative dimensional measurements in the micro- and submicrometer range. To make matters worse, there has been an increasing demand for measuring characteristics of sidewalls like line edge and line width roughness, wave pattern of sidewalls and angles of overhang features. Realizing that currently available CD-AFM or CD-SEM techniques do not satisfy this demand, new measurement standards are required for angles of micro- and nano-structures. In spite of the many capabilities of AFM, quite a few conditions have to be considered to measure critical dimensions (CD) quantitatively with repeatability and reproducibility. Piezo hysteresis, drift, tip shape and consistency, scanner orthogonality and other things are included in the conditions. The requirements and process to measure critical angle of nano- and micro-structure using AFM will be described in this paper.