Patent ID: 6296714
Filing Date: 2001-10-02
Classification: H01L

Abstract:
A method of washing a semiconductor substrate which comprises steps ofimmersing a semiconductor substrate on the surface of which a naturally oxidized film is formed, fine particles and metal impurities being on the naturally oxidized film, and metal impurities contained in the naturally oxidized film, in a mixed solution bath, the mixed solution containing 0.0001 to 0.1% by weight of an organic acid and 0.005 to 0.25% by weight of hydrofluoric acid and having a pH of 2 to 4, whereby the hydrofluoric acid removes the naturally oxidized film from the substrate and the mixed solution negatively charges fine particles liberated into the mixed solution as well as the surface of the substrate, and the organic acid forms complex salts with the negatively charged fine particles in the mixed solution, andirradiating the surface of the semiconductor substrate in the bath with a light consisting essentially of wavelengths of in the range of 500-900 nm to reduce and dissociate the organic acid in the mixed solution to enhance effect of removing metal impurities near to the surface of the substrate.