Substrate processing apparatus and substrate processing method

A substrate processing method for processing a substrate with a processing fluid in a supercritical state, the method comprising:

• (a) accommodating a support part into a processing space of a processing chamber, the support part having a substrate-facing surface facing a lower surface of the substrate when the substrate is supported by the support part, and being configured to support the substrate in a state of being spaced from the support-facing surface to define a lower laminar flow path between the substrate-facing surface and the lower surface of the substrate that is supported by the support part;
• and
• (b) processing the substrate supported by the support part inside the processing space by using the processing fluid, by supplying the processing fluid into the processing chamber that accommodates the support part therein to thereby cause the processing fluid to flow in a certain direction from an upstream position to a downstream position in the processing space and discharging the processing fluid that flows in the certain direction along an upper surface of the substrate and the processing fluid that flows between the support part and the substrate, from the processing chamber,
• wherein the lower laminar flow path extends from the upstream position to the downstream position, wherein the lower laminar flow path includes a downstream path section and an upstream path section, wherein the upstream path section merges with the downstream path section, and wherein a distance between the substrate-facing surface and the lower surface of the substrate at the downstream path section is larger than a distance between the substrate-facing surface and the lower surface of the substrate at the upstream path section.