| 摘要 |
PURPOSE:To have good response to eventual trouble in a main injection monitor by electrically insulating a beam mask to adjust the degree of convergence of an ion beam and its scanning width and to restrict the area of injection, and by using this mask to an electrode for sensing the beam current. CONSTITUTION:A water retainer 5 is installed at the opening on one end of a Farady cage 4, and on the other end, a beam mask 1 having an opening is installed electrically insulated by an insulator 2. This mask 1 and retainer 5 are connected to a lead 13 passed through a feed through 3 in a vacuum bulkhead 6. An ion beam in approx. square form from an electrostatic scanning system in such a structure as above is passed through the mask and irradiated onto a wafer 7 affixed to the retainer 5, while the beam caught by the mask 1 is put into an aux. ion beam monitor with built-in aux. current integrator 10 and CPU 11. The beam collected by the retainer 5 is put into the CPU 11 via a main current integrator 9 and also into the CPU 11 through integrator 9 and a scanning controller 12.
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