In reticle production for 90-nm node generation and beyond, quite strict chrome CD control is strongly demanded. For chrome dry-etching process, esetablishment of reliable system for chrome endpoint detection is one of critical issues. In this paper, the effectiveness of radio frequency (RF) sensor as a process monitor for chrome dry-etching was examined. As general endpoint detection system, such as Laser endpoint detection (Laser EPD) and optical emission spectroscopy (OES), the system based on RF sensor shows the ability to get chrome endpoint. Experimental data implied its competence as an endpoint detector for the plates of various chrome loads with enough stability and reliability. Moreover, this sensor has an advantage that plasma impedance observed with the sensor has a correlation with etching performance, such as etching bias and its uniformity. This property is useful, because feedback of the variation of sensor output to process condition is able to play important role in control of reticle CD. As a consequence, the concept of advanced process control based on the RF sensor is proposed.