PLASMA PROCESSING APPARATUS, PLASMA PROCESSING METHOD AND CLEANING TIME PREDICTION PROGRAM
The plasma processing apparatus relating to the present invention has a measurement circuit for measuring an antenna bias voltage that varies according to an amount of electrical charge between an inner wall of a chamber and plasma generated in the chamber. The obtained antenna bias voltage is converted to a statistical value and is stored in a statistical value memory unit after being associated with a number of particles attached on a workpiece during the same plasma processing that the antenna bias voltage is obtained. A correspondence acquisition unit obtains a correspondence the antenna bias voltage and the number of particles based on stored data in the statistical value memory. Then, a prediction unit predicts the antenna bias voltage at which the number of particles reaches to a pre-determined value based on the correspondence obtained by the correspondence acquisition unit.
1 . A plasma processing apparatus for plasma processing of a workpiece in a vacuum processing chamber using plasma generated in the vacuum processing chamber by applying high-frequency power to a plasma excitation electrode, comprising:
a unit obtaining a physical value which varies according to an amount of electrical charge between an inner wall of the vacuum processing chamber and the plasma generated in the vacuum processing chamber;
a unit recording by associating the obtained physical value with a number of particles attached on the workpiece during the plasma processing in which the physical value is obtained;
a unit obtaining a correspondence between the physical value and the number of particles based on the physical values and the numbers of particles obtained from a multiple rounds of the plasma processing; and
a unit predicting the physical value at which the number of particles reaches to a pre-determined specified value based on the correspondence.
2 . A plasma processing apparatus according to claim 1 , further comprising:
a unit determining whether a cleaning of the vacuum processing chamber is needed or not by comparing the predicted physical value with the physical value obtained during the plasma processing thereafter.
3 . A plasma processing apparatus according to claim 1 , further comprising:
a unit obtaining a correspondence between the physical values obtained from a multiple rounds of the plasma processing and an accumulation process time or an accumulation process count of the vacuum processing chamber after the cleaning of the vacuum processing chamber; and
a unit predicting a remaining process time reaching to the predicted physical value based on the correspondence between the physical value and the accumulated process time, or a remaining process count reaching to the predicted physical value based on the correspondence between the physical value and the accumulated process count.
4 . A plasma processing apparatus according to claim 3 , further comprising:
a unit determining a cleaning time of the vacuum processing chamber based on the predicted remaining process time or the predicted remaining process count and a production schedule for workpieces to be plasma-processed.
5 . A plasma processing apparatus according to claim 4 , wherein, in a case that the production schedule is modified, the unit determining the cleaning time determines the cleaning time of the vacuum processing chamber based on the modified production schedule.
6 . A plasma processing apparatus according to claim 1 , wherein the physical value is a self-bias potential of the plasma excitation electrode.
7 . A plasma processing method for plasma processing of a workpiece in a vacuum processing chamber using plasma generated in the vacuum processing chamber by applying high-frequency power to a plasma excitation electrode, comprising the steps of:
obtaining a physical value which varies according to an amount of electrical charge between an inner wall of the vacuum processing chamber and the plasma generated in the vacuum processing chamber;
associating the obtained physical value with a number of particles attached on the workpiece during the plasma processing in which the physical value is obtained;
obtaining a correspondence between the physical value and the number of particles based on the physical values and the numbers of particles obtained from a multiple rounds of the plasma processing; and
predicting the physical value at which the number of particles reaches to a pre-determined specified value based on the correspondence.
8 . A plasma processing method according to claim 7 , further comprising a step of:
determining whether a cleaning of the vacuum processing chamber is needed or not by comparing the predicted physical value with the physical value obtained during the plasma processing thereafter.
9 . A plasma processing method according to claim 7 , further comprising the steps of:
obtaining a correspondence between the physical values obtained from a multiple rounds of the plasma processing and an accumulation process time or an accumulation process count of the vacuum processing chamber after the cleaning of the vacuum processing chamber; and
predicting a remaining process time reaching to the predicted physical value based on the correspondence between the physical value and the accumulated process time, or a remaining process count reaching to the predicted physical value based on the correspondence between the physical value and the accumulated process count.
10 . A plasma processing method according to claim 9 , further comprising a step of:
determining a cleaning time of the vacuum processing chamber based on the predicted remaining process time or the predicted remaining process count and a production schedule for workpieces to be plasma-processed.
11 . A plasma processing method according to claim 10 , wherein, in a case that the production schedule is modified, the cleaning time of the vacuum processing chamber is determined based on the modified production schedule.
12 . A plasma processing method according to claim 7 , wherein the physical value is a self-bias potential of the plasma excitation electrode.
13 . A cleaning time prediction program for predicting a cleaning time of a plasma processing apparatus for plasma processing of a workpiece in a vacuum processing chamber using plasma generated in the vacuum processing chamber by applying high-frequency power to a plasma excitation electrode, comprising the steps of:
recording by associating a physical value, which varies according to an amount of electrical charge between an inner wall of the vacuum processing chamber and the plasma generated in the vacuum processing chamber, with a number of particles attached on the workpiece during the plasma processing in which the physical value is obtained;
obtaining a correspondence between the physical value and the number of particles based on the physical values and the numbers of particles obtained from a multiple rounds of the plasma processing;
predicting the physical value at which the number of particles reaches to a pre-determined specified value based on the correspondence;
obtaining a correspondence between the physical value obtained from a multiple rounds of the plasma processing and an accumulated process time or an accumulated process count of the vacuum processing chamber after the cleaning of the vacuum processing chamber; and
predicting a remaining process time reaching to the predicted physical value based on the correspondence between the physical value and the accumulated process time, or a remaining process count reaching to the predicted physical value based on the correspondence between the physical value and the accumulated process count.