Substrate washing and drying apparatus, substrate washing method, and substrate washing apparatus

A substrate washing and drying apparatus comprising:

• a processing section having a capacity to accommodate a boat for holding a plurality of substrates such that the substrates are upright;
• a supply/discharge port provided on a lower portion of the processing section;
• first process solution supplying means for supplying a first process solution into said processing section through said supply/discharge port for washing the substrates;
• second process solution supplying means for supplying a second process solution into said processing section through said supply/discharge port for washing the substrates;
• process solution discharging means for discharging at least one of said first and second process solutions from said processing section through said supply/discharge port;
• a drying vapor generating section having heating means for generating vapor for drying;
• a drying vapor supply passage communicating with each of said drying vapor generating section and said processing section for supplying said vapor for drying to said processing section;
• a forcible discharging solution mechanism provided at the lower portion of said processing section and having at least one opening for rapidly discharging the process solution from said processing section when said at least one opening is unblocked;
• a resistivity measuring device for detecting a resistivity value of the process solution of said processing section;
• and
• controlling means for controlling the supply of the first and second process solutions to the processing section from said first and second process solution supply means, respectively, based on the resistivity value detected by said resistivity measuring device and for rapidly discharging the first process solution from said processing section by means of said forcible discharging solution mechanism after the substrates have been washed by the first process solution, said controlling means controlling the second process solution supplying means to introduce said second process solution into said processing section and subsequently controlling introduction of the vapor for drying into said processing section through said drying vapor supply passage while the second process solution is being gradually discharged from said processing section by said process solution discharging means after the substrates have been washed by the second process solution.