Patent ID: 9653357
Date: 2017-05-16
CPC Classifications: H01J,H01L

Claim:
1. A plasma etching apparatus comprising: a housing defining a plasma processing chamber; workpiece retaining means for retaining a workpiece on an upper surface of the workpiece retaining means, the workpiece retaining means being disposed within the plasma processing chamber; processing gas injecting means for injecting a processing gas for plasma generation onto the workpiece retained by the workpiece retaining means, the processing gas injecting means having a processing gas jetting portion including a central injecting portion and a peripheral injecting portion surrounding the central injecting portion; processing gas supply means for supplying the processing gas to the processing gas injecting means, the processing gas supply means including a processing gas supply source, a buffer tank communicating with the processing gas supply source and temporarily containing the processing gas, a central injecting portion supply path making the buffer tank and the central injecting portion communicate with each other, a peripheral injecting portion supply path making the buffer tank and the peripheral injecting portion communicate with each other, a first high-frequency opening and closing valve disposed in the central injecting portion supply path, a second high-frequency opening and closing valve disposed in the peripheral injecting portion supply path, and control means for controlling an opening and closing frequency of the first high-frequency opening and closing valve at a first frequency and an opening and closing frequency of the second high-frequency opening and closing valve at a second frequency, and wherein the first frequency is different from the second frequency; and pressure reducing means for reducing a pressure within the plasma processing chamber.