Patent ID: 7513263

Claim:
A substrate holding device for holding a substrate and rotating the held substrate, comprising: a motor; a rotating shaft rotated by the driving force of the motor; a spin base coupled to the rotating shaft and rotated integrally with the rotating shaft; a cover member surrounding the motor and having its one end arranged in the vicinity of the spin base; a rotating ring fixed to a surface, opposite to the cover member, of the spin base; a non-rotatable fixed ring arranged opposite to the rotating ring along the axis of the rotating shaft, the non-rotatable fixed ring having a gas path; a spring provided at the one end of the cover member for elastically urging the non-rotatable fixed ring toward the rotating ring; and clean gas supply mechanism for supplying clean gas to a space between the rotating ring and the non-rotatable fixed ring, a surface, opposite to the non-rotatable fixed ring, of the rotating ring being formed with a gas introducing recess into which the clean gas is to be introduced by the clean gas supply mechanism, the gas path of the non-rotatable ring being connected to the gas introducing recess to supply gas to the gas introducing recess and to separate the rotating ring from the non-rotatable ring using a static pressure of the supplied gas, the gas introducing recess being a groove extending along a circumference of the rotating ring, and said surface, opposite to the non-rotatable fixed ring, of the rotating ring further being formed with a dynamic pressure creating recess for creating the dynamic pressure of gas between the rotating ring and the non-rotatable fixed ring when the rotating ring rotates; wherein the gas introducing recess and the dynamic pressure creating recess are continuous with each other.