PURPOSE: To temporarily seal and protect a cavity by dissolving a solid sublimate and applying it in the cavity and charging it into the cavity by heat treatment, and then, removing the sublimate by sublimation.
CONSTITUTION: Naphthalene as a sublimate and isopropyl alcohol IPA as a solvent are mixed and compounded. A wafer substrate 302 is set on a heater 301 and it is heated. Using a pipet 304, the sublimate solution 303 is dropped to the center of the wafer board, and a naphthalene solution layer is made on the surface of the board. The IPA of the solution layer evaporates preferentially, and the solution is condensed. When this advances, the solid phase of naphthalene is deposited in the vicinity of the surface of the solution layer, and the temperature goes up again, and the solid phase dissolves. When this is cooled to room temperature, the vacant space 108 is charged with naphthalene crystals. The naphthalene crystals can be maintained for eight hours or more at normal temperature and normal pressure, and the naphthalene is hydrophobic, so it can protect the cavity part by preventing the penetration of water in the dieing process thereby prevent the pollution.
IWASAKI YASUKAZU
UCHIYAMA MAKOTO
