Plasma processing apparatus and plasma processing method
A plasma processing apparatus or method that improves the yield of wafer processing, including a sample stand on which the wafer is mounted; plural heaters which are arranged in three or more regions in the radial direction including a circular region concentrically arranged around the center and ring-like regions surrounding the outer periphery on plural radii in the radial direction from the center toward the outer peripheral side, and which include one arranged in each of plural arc-like regions divided in the circumferential direction around the center of at least one of the ring-like regions; plural temperature sensors arranged in the radial direction and the number of which is smaller than that of heaters; and a control unit which adjusts the output of each of the plural heaters according to the output from the temperature sensor so that the temperature of the sample stand becomes closer to a target value.
1. A plasma processing method in which a wafer to be processed is mounted on a sample stand arranged in a processing chamber inside a vacuum container and plasma is formed in the processing chamber to process the wafer,
wherein the sample stand having a cylindrical shape has therein a plurality of heaters which are arranged in three or more regions in a radial direction including a circular region concentrically arranged around a center and ring-like regions surrounding an outer periphery of the circular region on a plurality of radii in the radial direction from the center toward an outer peripheral side and which include one of the plurality of heaters arranged in each of a plurality of arc-like regions divided in the circumferential direction around the center of at least one of the ring-like regions, and a plurality of temperature sensors which are arranged inside the sample stand under the respective regions in the radial direction and a number of which is smaller than that of the plurality of heaters,
the plasma processing method comprising:
a first step and a second step of processing the wafer; and
a transition step which occurs between the first and second steps of processing the wafer in which a temperature of the wafer or the sample stand is changed from a first temperature in the first step to a second temperature in the second step,
wherein the transition step further comprises adjusting an output of each of the plurality of heaters by a feedback control of an output from the temperature sensor so that the temperature of the sample stand becomes closer to a target value, and
wherein the second processing step after the transition step further comprises adjusting an amount of power supplied to each of the plurality of heaters to match or maintain a predetermined value which is detected by using data obtained in advance indicating a relation between the temperature of the sample stand and the amount of power supplied to each of the plurality of heaters.
2. The plasma processing method according to claim 1 ,
wherein the predetermined value of the amount of power supplied to each of the plurality of heaters maintains the temperature of the sample stand within an allowable range including the target value.
3. The plasma processing method according to claim 1 ,
wherein each of the plurality of temperature sensors is arranged within a region where each of the plurality of regions in the radial direction is projected when viewed from above.
4. The plasma processing method according to claim 1 ,
wherein each of the arc-like regions has a length in the circumferential direction larger than that in the radial direction.
5. The plasma processing method according to claim 1 ,
wherein the heaters in the respective regions in the radial direction are adjusted to have the same output.
6. The plasma processing method according to claim 5 ,
wherein at least one of the ring-like regions further comprises a plurality of ring-like regions concentrically arranged on a plurality of radii in the radial direction or the plurality of arc-like regions divided in the circumferential direction around the center, and the plurality of heaters is arranged inside the sample stand under the respective regions.