| 摘要 |
To provide for digital positioning, without inertia of moving parts, a laser beam is transmitted to a substrate which is to be exposed, etched, or the like, particularly when microcircuits are to be produced, by monitoring the displacement of the substrate, mechanically, in two mutually perpendicular directions and positioning the laser beam, as monitored, in at least one direction by controlling voltages applied to a deflector cell in the path of the laser beam, by digitally, selectively, energizing an electro optical crystal effective to rotate the polarized laser beam through a plane of 90 DEG , followed by a doubly refracting crystal which deviates the path of the laser beam, depending on its direction of polarization with respect to the optical axis of the crystal, so that, by successive deflections, the beam, from the laser, can be positioned in predetermined locations on the substrate. The entire arrangement is preferably computer controlled, so that data inserted into the computer will cause deflection of the laser beam in accordance with a predetermined program.
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