Taper etchable molybdenum (Mo) films are successfully obtained by neon (Ne) sputter deposition. Mo films several hundred nanometer thick are deposited using an RF planar magnetron sputtering system. After photolithography, the Ne-sputtered Mo films are etched with a hydrogen peroxide solution. Films deposited in low pressure Ne show an excellent tapered edge with a taper angle of less than 45°, which can eliminate the step-coverage problem. However, higher-pressure Ne-sputtered films and films sputtered in argon (Ar) show steep edge profiles .

Ne-sputtered Mo films show a drastic change in characteristics depending on the gas pressure. The internal stress is strongly compressive for lower pressures and becomes tensile for higher pressures. According to RHEED patterns, lower pressure sputtered film shows a <110> orientation including a halo which indicates the existence of an amorphous-phase, but higher pressure sputtered films show clear <111> orientations. TEM observations confirm the structural change. Higher pressure Ne-sputtered film and Ar-sputtered film show columnar structures, but low-pressure Ne-sputtered film shows the disordered structure.

Taper etchability of the low-pressure Ne-sputtered Mo films is considered to be due to the structural change, especially the included amorphous-phase.