Patent ID: 8042560

Claim:
A substrate processing apparatus comprising: a substrate holding member configured to rotate along with a substrate held thereon in a horizontal state; a rotation mechanism configured to rotate the substrate holding member; a process liquid supply mechanism configured to supply a process liquid onto the substrate; a rotary cup disposed outside the substrate holding member to surround the substrate held on the substrate holding member and to rotate along with the substrate holding member, and having a wall portion that receives the process liquid thrown off from the substrate being rotated; an exhaust and drain cup disposed outside the rotary cup to surround the rotary cup and the substrate holding member, and including an annular liquid receptacle that receives the process liquid thrown off from the substrate being rotated and an inner annular space formed on an inward side from the annular liquid receptacle; and an exhaust mechanism connected to the inner annular space of the exhaust and drain cup, wherein the exhaust and drain cup further includes a lower annular space present directly below the liquid receptacle and defined by an inner periphery connected to the inner annular space and an outer periphery completely closed, the exhaust mechanism is connected through the lower annular space to the inner annular space, the exhaust and drain cup includes an annular outer wall, an annular inner wall, a bottom wall, and a built-in frame forming the liquid receptacle inside a space surrounded by the walls, such that the inner annular space is formed between the annular inner wall and the built-in frame, and the lower annular space is formed between the bottom wall and the built-in frame, and a gap is formed between an inner end of the built-in frame and the bottom wall and sets the inner annular space to communicate with the lower annular space.