Rectangular etching ion gun

The invention relates to a rectangular etching ion gun which comprises a first pole shoe, a second pole shoe, a third pole shoe, a fourth pole shoe, a first magnet, a second magnet, a fourth pole shoe, a rectangular annular upper anode, a rectangular annular lower anode, a rectangular conical surface, an arc plate-shaped screen grid, an arc plate-shaped accelerating grid, a base, a cathode lamp, a lamp filament and an inflating pipe, wherein the first pole shoe, the second pole shoe, the third pole shoe and the fourth pole shoe are coaxially arranged from bottom to top; the first magnet is positioned between the end surfaces of the first pole shoe and the second pole shoe; the second magnet is positioned between the end surfaces of the second pole shoe and the third pole shoe; the fourth pole shoe is positioned on the end surface of the third pole shoe; the rectangular annular upper anode is positioned in the second magnet; the rectangular annular lower anode is positioned between the first magnet and a rectangular pipe; the rectangular conical surface with high outside and low inside is arranged on the upper end surface of the rectangular annular lower anode; the arc plate-shaped screen grid is overlapped at the upper end surface of the fourth pole shoe; the arc plate-shaped accelerating grid is suspended on the screen grid; the base is arranged in the center of the lower surface of the first pole shoe and covers an inner hole of the rectangular pipe; the cathode lamp is fixed on the base and positioned in the rectangular pipe; the lamp filament is positioned in a rectangular ring of the rectangular annular upper anode; and the inflating pipe is positioned between the rectangular pipe and the cathode lamp after penetrating through the base and communicated with an argon source. The invention has the advantages of less etching gas dosage, small size, low power consumption, even ion beam, and the like.