| 摘要 |
PURPOSE:To prevent a semiconductor substrate from being adversely affected when high-density ions are implanted by applying the uniform potential distribution with the preset polarity to a disk fitted with the semiconductor substrate. CONSTITUTION:When a constant-voltage source 8 applying the optional positive bias voltage to a disk 4 is provided, the optional positive bias voltage is applied to an element produced in a semiconductor substrate 3, e.g., gate section A of MOS transistor, by the constant-voltage source 8. As a result, in the case of implantation of high-density ions into the semiconductor substrate 3, electric charges are accumulated at the gate section A when ions are implanted, and the voltage V1 causing the electrostatic breakdown at this portion tends to occur. However, the voltage V2 to compensate for the voltage V1 is applied to the gate section A by the constant-voltage source 8, thus the voltage V1 is offset by the voltage V2. Accordingly, the breakage of the element produced in the semiconductor substrate 3 can be prevented or reduced.
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