Method for drying microstructure member

A method for drying a microstructure member having a large number of micro concavities in a surface, the micro concavities containing water, the method comprising the steps of:

• (1) adjusting the temperature of a liquid inside the micro concavities to a temperature in the range of the cloud point of a surfactant (A) ±1° C., and supplying a large amount of a mixture of the surfactant (A) and a hydrophobic solvent (B) adjusted to a temperature in the range of the cloud point of the surfactant (A) ±1° C. into the micro concavities to remove part or all of the water inside the micro concavities;
• (2) heating the liquid inside the micro concavities to a temperature exceeding the cloud point of the surfactant (A) +1° C., and supplying a large amount of the hydrophobic solvent (B) controlled to a temperature exceeding the cloud point of the surfactant (A) +1° C. into the micro concavities to replace the liquid in the concavities with the hydrophobic solvent (B);
• and
• (3) placing the microstructure member comprising the concavities containing the hydrophobic solvent (B) into contact with liquid carbon dioxide or supercritical carbon dioxide to replace the hydrophobic solvent (B) with the liquid carbon dioxide or the supercritical carbon dioxide,
• wherein Steps (1) and (2) are performed under atmospheric pressure.