Patent ID: 7842229

Claim:
A substrate processing apparatus comprising: a process vessel defining a processing space for processing a substrate; a substrate support member that supports the substrate within the process vessel; a driven rotary member connected to the substrate support member and a driving rotary member that rolls the driven rotary member to cause the driven rotary member to rotate, thereby to cause the substrate support member to rotate, wherein a contact surface of the driven rotary member that contacts with the driving rotary member is a toothless surface of revolution, and a contact surface of the driving rotary member that contacts with the contact surface of the driven rotary member also is a toothless surface of revolution, the driven rotary member and the substrate support member are supported by the driving rotary member; and the driven rotary member and the driving rotary member are formed of ceramic materials with binder contents that are different from each other to provide different values of fracture toughness as defined by JIS R1607, and/or different three-point bending strengths as defined by JIS R1601.