Substrate processing method
Examples of a substrate processing method include subjecting a substrate placed on a susceptor to plasma processing, applying power to an RF electrode facing the susceptor for only a predetermined static electricity removal time to generate plasma, thereby reducing an amount of charge of the substrate, measuring a self-bias voltage of the RF electrode while susceptor pins are made to protrude from a top surface of the susceptor and lift up the substrate, and by a controller, shortening the static electricity removal time when the self-bias voltage has a positive value, and lengthening the static electricity removal time when the self-bias voltage has a negative value.
1. A substrate processing method comprising:
plasma processing a substrate placed on a susceptor;
applying power to an RF electrode facing the susceptor for only a first predetermined static electricity removal time to generate a plasma after the plasma processing, thereby reducing an amount of charge of the substrate;
measuring a self-bias voltage of the RF electrode after generation of the plasma while susceptor pins are made to protrude from a top surface of the susceptor and lift up the substrate; and
by a controller that is configured to shorten static electricity removal time based entirely on the self-bias voltage and to lengthen static electricity removal time based entirely on the self-bias voltage, shortening a subsequent static electricity removal time when the self-bias voltage has a positive value, and lengthening the subsequent static electricity removal time when the self-bias voltage has a negative value, and after the subsequent static electricity removal time has been lengthened or shortened, plasma processing a subsequent substrate placed on the susceptor followed by applying the power to the RF electrode facing the susceptor for the subsequent static electricity removal time.
2. The substrate processing method according to claim 1 , wherein each of the static electricity removal times includes:
a respective first time for which the power is applied to the RF electrode to generate the plasma;
a respective second time for which the power applied to the RF electrode is decreased at a predetermined first rate after the first time has elapsed; and
a respective third time for which the power applied to the RF electrode is decreased down to 0 at a predetermined second rate after the second time has elapsed.
3. The substrate processing method according to claim 2 , wherein the controller shortens the second time of the subsequent static electricity removal time when the self-bias voltage has the positive value, and lengthens the second time of the subsequent static electricity removal time when the self-bias voltage has the negative value.
4. The substrate processing method according to claim 2 , wherein the second time is longer than the third time.
5. The substrate processing method according to claim 1 , wherein the controller changes the subsequent static electricity removal time according to a recipe for processing the subsequent substrate.
6. The substrate processing method according to claim 1 , wherein the controller makes the subsequent static electricity removal time longer as plasma power of the plasma processing is increased.
7. A substrate processing method comprising:
plasma processing a first substrate of a set of first substrates placed on a susceptor, then applying power to an RF electrode facing the susceptor for only a predetermined static electricity removal time to reduce an amount of charge of the first substrate by generating plasma, and then measuring at least a first self-bias voltage of a plurality of self-bias voltages of the RF electrode when susceptor pins are made to protrude from a top surface of the susceptor and lift up the first substrate while the predetermined static electricity removal time is changed to a first subsequent static electricity removal time to be used for a subsequent first substrate of the set of first substrates and then plasma processing the subsequent first substrate of the set of first substrates placed on the susceptor, then applying the first subsequent static electricity removal time to the subsequent first substrate of the set of first substrates, and then measuring at least a second self-bias voltage of a plurality of self-bias voltages of the RF electrode when susceptor pins are made to protrude from the top surface of the susceptor and lift up the subsequent first substrate;
determining from the plurality of self-bias voltages a self-bias voltage having a minimum absolute value;
subjecting a second substrate placed on the susceptor to the same plasma processing as the plasma processing for the subsequent first substrate; and
determining a second subsequent static electricity removal time from the self-bias voltage having the minimum absolute value, and applying the power to the RF electrode for only the second subsequent determined static electricity removal time, thereby reducing an amount of charge of the second substrate.
8. The substrate processing method according to claim 7 , wherein each of the first substrates is a dummy substrate, and the second substrate is a product substrate.
9. The substrate processing method according to claim 7 , wherein each of the static electricity removal times includes:
a first time for which the power is applied to the RF electrode to generate the plasma;
a second time for which the power applied to the RF electrode is decreased at a predetermined first rate after the first time has elapsed; and
a third time for which the power applied to the RF electrode is decreased down to 0 at a predetermined second rate after the second time has elapsed.
10. The substrate processing method according to claim 9 , wherein the second time is longer than the third time.