Patent ID: 7372027

Claim:
An electron beam apparatus comprising: a sampled chamber grounded by a first grounding point and comprising a magnetic substance; a column connected to the sample chamber and comprising a magnetic substance; an exhaust section controlling a pressure in the sample chamber and a pressure in the column and grounded by a second grounding point; a stage provided in the sample chamber, a sample being placed above the stage; a stage controller driving the stage and grounded by a third grounding point; an electron beam source provided in the column and emitting an electron beam to the sample; an electron beam source power supply supplying power to the electron beam source and grounded by a fourth grounding point; an electron optic system provided in the column and controlling the electron beam; and a power supply supplying voltage to the electron optic system and grounded by a fifth grounding point; wherein the electron beam source and the electron optic system are electrically insulated from the sample chamber, the column, the exhaust section and the stage, and a grounding point selected from a group including the first grounding point, the second grounding point and the third grounding point is different from either the fourth grounding point or the fifth grounding point.