PURPOSE: To recover Cu element with high efficiency and to quantitatively analyze the contaminant Cu element by dissolving the deposit on the surface of a semiconductor wafer in a solvent and adding triene to the soln. to form a complex of Cu and triene.

CONSTITUTION: A semiconductor wafer 15 deposited with Cu and with the surface turned upward is horizontally placed on a wafer holder 14 arranged on one side in a closed vessel 10, a beaker 11 contg. a soln. 12 of hydrofluoric acid, etc., is arranged on the other side in the vessel 10 and let stand at ordinary temp., and the vapor 13 of the hydrofluoric acid, etc., is allowed to react with the oxide layer on the Si wafer 15 surface. An aq. soln. contg. triene is dripped on the droplet 16 as the reactional product, the droplet is rolled over the wafer 15 surface, and the reaction liq. is collected. The reaction liq. is quantitatively analyzed by an atomic absorption-photometer in a graphite furnace. The Cu element is recovered with almost 100% efficiency by this method, and the contaminant Cu is quantitatively analyzed with high efficiency.