| abstract |
PROBLEM TO BE SOLVED: To provide a cleaning method for cleaning an object to be cleaned without damaging the object to be cleaned having a microstructure. SOLUTION: In this cleaning method, a supercritical carbon dioxide to which a nonionic surfactant is added is used as a cleaning liquid, and a micromachine having a beam structure formed by etching, for example, a sacrificial layer as a body to be cleaned is cleaned. The added nonionic surfactant is, for example, nonylphenol polyoxyethylene ether represented by the following chemical formula. Embedded image (Ethylene oxide (CH 2 —CH 2 —O) mole number n in the chemical formula is 2 to 4) The addition amount of the nonionic surfactant is, for example, the concentration of the nonionic surfactant in supercritical carbon dioxide at 40 ° C. and 8 MPa is 0.01 mol% or more and 2 mol% or less, preferably 0.05 mol% or more and 1 mol% or less. The amount is such that the concentration range is [Selection diagram] None |