The fluorine-doped n-type superconductors Nd 1 . 8 5 Ce 0 . 1 5 CuO 4 - x - y F y (nominal composition) are synthesized with CuF 2 as one of the reactants. Especially, it is found that the superconductivity of Nd 1 . 8 5 Ce 0 . 1 5 CuO 4 - δ is improved with T c o n = 27 K, T c 0 = 15.5 K when CuF 2 is taken as a source of atmosphere; the temperature dependence of the resistance exhibits a metallic conducting behavior above T c . Magnetization measurements showed 30% of superconducting phase fractions by means of SQUID magnetometry, which was a better result of superconductivity in (Nd,Ce) Cu O bulk samples than when prepared under ambient pressure. Compared with the case of F undoping, F doping not only induces a transition from semiconductivity to metallic conductivity and decreases the normal-state resistivity, but also increases the T c o n and T c 0 , and decreases the transition width ΔT c . In particular, the superconductivity of the samples is sensitive to the form of the dopant source and sintering procedures. Especially, the Nd 1 . 8 5 Ce 0 . 1 5 CuO 3 . 6 F 0 . 4 sintered only in air also exhibits superconductivity with T c o n = 19.5 K, but does not reach zero resistance, which has not been reported before. X-ray diffraction experiments indicate that fluorine atoms do enter the superconducting phase lattice.