Patent ID: 11929234
Assignee: TOHOKU UNIVERSITY
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A plasma processing apparatus including a lower stage configured to generate plasma with an upper electrode, the lower stage comprising:
a lower dielectric body formed of ceramic;
a lower electrode embedded in the lower dielectric body; and
a heating element embedded in the lower dielectric body,
wherein a separation distance (dedge) between a top surface of the lower dielectric body at an outer edge position thereof and the lower electrode is smaller than a separation distance (dcenter) between the top surface of the lower dielectric body in a central region thereof and the lower electrode,
wherein the lower electrode has an inclination region inclined with respect to the top surface between the outer edge position and the central region,
wherein VHF power is supplied to a space between the upper electrode and the lower electrode, and
wherein, when a three-dimensional orthogonal coordinate system having a Z axis set in a downward direction of a normal in a thickness direction at a center of the lower electrode, an X axis perpendicular to the Z axis, and a Y axis perpendicular to both the Z axis and the X axis is set, and an origin of the coordinate system is a gravity center position of the top surface of the lower dielectric body, and
when it is assumed that a relative permittivity of the lower dielectric body is εr, a speed of light is c, a frequency of VHF power is f, a circular constant is π, and a wave number of VHF power in the dielectric body is k(=(εr)0.5·2πf/c),
a position (x, z) of the top surface of the lower electrode in an XZ plane is set to satisfy a following equation:

dx/dz=−2/xk·cot(kz).