A method of forming a Ta—Ru metal liner layer for Cu wiring includes: (i) conducting atomic deposition of Ta X times, each atomic deposition of Ta being accomplished by a pulse of hydrogen plasma, wherein X is an integer such that a surface of an underlying layer is not covered with Ta particles; (ii) after step (i), conducting atomic deposition of Ru Y times, each atomic deposition of Ru being accomplished by a pulse of hydrogen plasma, wherein Y is an integer such that the Ta particles are not covered with Ru particles; and (iii) repeating steps (i) and (ii) Z times, thereby forming a Ta—Ru metal liner layer on a Cu wiring substrate.