Reaction of copper oxide and beta-diketone for in situ cleaning of metal copper in a copper chemical vapor deposition reactor

For ill situ cleaning of inner reactor walls of copper chemical vapor depos ition chambers used in the copper wiring process of LSI, etching of the dep osited metallic copper is carried out by three step processes of copper oxi dation, complexation with beta -diketone, and vaporization to allow evacuat or, in this paper, reactions suitable for the latter two processes are desc ribed. Reactions of copper oxide with three kinds of beta -diketone, hexafl uoroacetylacetone (Hhfac), acetylacetone and dipivaloylmethane, were studie d using thermogravimetry in the range from room temperature to 400 degreesC . Only Hhfac reacted with copper oxide showing etching in the temperature r ange above 170 degreesC. Al 350 degreesC the weight ratio etching rate was 0.29 wt%/min at atmospheric pressure and 0.06 wt%/min at 665 Pa. The evapor ation rate of the reaction product, Cu(hfac)(2), was 5.3 wt%/min at 150 deg reesC, which is sufficiently higher than the etching rate of copper oxide. Reactions are as follows: 2CuO --> Cu2O + 1/2O(2), Cu2O + Hhfac --> Cu(hfac ) + CuOH, 2Cu(hfac) --> Cu(hfac)(2) + Cu, and Cu + CuO --> Cu2O.