Wafer Center Alignment System of Transfer Robot Based on Reduced Number of Sensors

Abstract

This brief presents a wafer alignment algorithm with reduced sensor number that obtains the relative distance of the wafer center and the robot hand. By `reduced number’, in spite of smaller number of sensors than the conventional method, we mean an improved method which achieves the similar results to pre-existing algorithms. Indeed, it can be designed with only three sensor data, less than four sensors of the conventional algorithm. Thus, some advantages of the proposed alignment algorithm include that it can be designed with low cost and less computing power. The proposed alignment algorithm is applied to a transfer robot for coater/developer system in semiconductor processing for verifying the performance of the method. The performance of the proposed method is validated by both simulation and experimental results.

A coarse to fine calibration method for the q-X-Z type wafer pre-alignment device

“…Vision-based methods use cameras to capture the surface information image through a single shot [3] or multiple shots [4] and obtain the wafer edge data through edge detection, Hough transform, and other digital image processing techniques. The laser sensor-based methods restore wafer profiles using compact triangulation laser position sensors [5] or laser light curtain sensors [6]. The laser sensor-based methods tremendously reduce the computing resource requirements compared with the vision-based methods.…”

Research on Motion Control and Wafer-Centering Algorithm of Wafer-Handling Robot in Semiconductor Manufacturing

“…Reference [11] presents a systematic approach to distributing wafers to maximize wafer yield while meeting predetermined target productivity levels. Reference [12] describes a wafer alignment algorithm that reduces the number of sensors to obtain the relative distance between the wafer center and the manipulator. It can be designed with only three sensor data, which is less than the four sensors of traditional algorithms.…”