Etching uniformity regulating device and method
An etching uniformity regulating device and method. The device comprises an inductor and a capacitor connected in parallel. One end of the etching uniformity regulating device is connected to a built-in ring located at the edge of an electrostatic chuck of an etching machine, and the other end is grounded. The purpose of controlling the edge electric field is achieved by regulating a capacitance of the capacitor, so as to regulate the etching rate of the edge, thereby achieving etching uniformity.
1. An etching regulating method, which uses an etching regulating device comprising an inductor and a capacitor connected in parallel, wherein one end of the etching regulating device is connected to a built-in ring located at the edge of an electrostatic chuck of an etching machine and another end is grounded, wherein
the method comprises following steps:
determining whether a resonance frequency of the etching regulating device is equal to the frequency of a lower electrode radio-frequency power supply of an etching machine; and
when a determining result is no, regulating a capacitance of the capacitor of the etching regulating device, so that the resonance frequency of the etching regulating device approaches the frequency of the lower electrode radio-frequency power supply of the etching machine, thus rendering an etching rate at the edge of a wafer and the etching rate at the center of the wafer consistent.
2. The etching regulating method according to claim 1 , wherein
when the resonance frequency of the etching uniformity regulating device is less than the frequency of the lower electrode radio-frequency power supply, the capacitance of the capacitor of the etching regulating device is increased, so that the etching rate at the edge of the wafer is gradually reduced.
3. The etching uniformity regulating method according to claim 1 , wherein
when the resonance frequency of the etching regulating device is greater than the frequency of the lower electrode radio-frequency power supply, the capacitance of the capacitor of the etching regulating device is decreased, so that the etching rate at the edge of the wafer is gradually increased.
4. The etching regulating method according to claim 1 , wherein
the inductor is an air-core or magnetic-core inductor, and a self-resonance frequency (SRF) of the inductor is greater than a frequency of a lower electrode radio-frequency power supply of the etching machine.
5. The etching regulating method according to claim 4 , wherein the SRF of the inductor is not more than 2 times the frequency of the lower electrode radio-frequency power supply.
6. The etching regulating method according to claim 4 , wherein
the SRF of the capacitor is more than 5 times the frequency of the lower electrode radio-frequency power supply.
7. The etching regulating method according to claim 1 , wherein the capacitor is an adjustable or motor capacitor.