The present disclosure provides a plasma process method, which includes: introducing a reaction gas, putting a wafer into a reaction chamber, exciting a plasma, then performing a wafer etching process, and setting the etching process to different processing stages along with the increase of an etching depth, where each processing stage includes an etching step and a modification step, the etching step is used to increase the etching depth, the modification step is used to trim the shape of a side wall of an etched structure, and the temperature of the wafer in each step is gradually increased with the increase of the etching depth. By the process method and the device using the process method, good upper and lower feature size consistency can be ensured when deep hole etching is performed.