Development of Microwave Patch Antenna Sensor for Plasma Uniformity Monitorin

Real-time and accurate diagnosis of electron density is essential in current and next-generation semiconductors and display plasma processes to enhance wafer processing outcomes and increase production yield. Microwave plasma diagnostic methods, such as the flat cutoff sensor, have been explored; however, most existing sensors require maintaining a coaxial structure up to the sensing point or have a thickness of several millimeters. To overcome these limitations, we developed a Patch-Type Cutoff Sensor, which enables microwave transmission and plasma diagnosis without needing a continuous coaxial structure. The sensor structure was optimized through electromagnetic wave simulations, which also confirmed the measurement accuracy under varying plasma conditions. Its capability to detect bulk plasma characteristics was experimentally demonstrated. Additionally, the sensor's potential for predicting wafer processing results was confirmed by comparing sensor diagnostics with actual process outcomes, highlighting its value as a diagnostic tool in semiconductors and display manufacturing processes.