Oblique injection of argon ions with energy of 1 keV was conducted for etching of polycrystalline copper. The surface became rough owing to the formation of blisters. The average diameter and height of blisters was approximately 150 and 20–30 nm, respectively. The polycrystalline copper irradiated by argon ions was annealed to rupture the blisters. The retained argon desorbed in the temperature range from 500 to 800 K. The height of blisters significantly reduced to 10–15 nm although the diameter and surface density of blisters roughly remained the same.