The growth of gaseous neutral species and positive ions was investigated in the downstream region of Ar/CF4 plasmas by mass spectrometry. As a result. there were several series of CnF2n+1+ (n = 1-7), CnF2n-1+ (n = 3-8) and CnF2n-3+ (n = 4-9) for the positive ions and CnF2n+2 (n = 2-7) and C(n)F2(n) (n = 4-8) for the neutral species. The intensity dependence of the positive ions on the partial pressure of CF4 was quite different from that of the neutral species, demonstrating that their growth mechanisms are independent of each other.