Replaceable shielding apparatus
A replaceable shielding apparatus provides a cost effective way of shielding a portion of a workpiece during processing. The apparatus includes a replaceable shield, made of comparable weight as the workpiece for allowing replacement of the shield in the same way as the replacement of the workpiece. With this feature, the replacement of the shield is a routine process and would not interfere much with the workpiece operation. The invention further includes a shield clamp for clamping the shield onto the workpiece. In a preferred embodiment, the invention further includes a non-reactive gas inlet for creating a pressurized cavity in the vicinity of the shielded portion of the workpiece.
1. A workpiece deposition system for replaceably preventing deposition on a portion of a workpiece comprising:
a) a chamber for depositing a film on the workpiece;
b) a workpiece support positioned within the chamber for supporting the workpiece;
c) a replaceable shield of comparable weight as the workpiece, the shield engaging a portion of the workpiece on the opposite side of the workpiece support and shielding the engaged portion of the workpiece during deposition thereof to prevent deposition on the engaged portion of the workpiece;
d) an actuator to move and engage and disengage the shield with the portion of the workpiece;
e) a shield restraint clamp for holding the shield against the portion of the workpiece; and
f) a cavity defined by the workpiece support, the workpiece, the shield and the shield restraint clamp, the cavity adapted to retain a non-reactive gas in the vicinity of the shielded portion of the workpiece;
wherein the comparable weight of the replaceable shield and the workpiece allows replacement of the shield in the same way as the replacement of the workpiece.
2. An apparatus as in claim 1 in which the shield restraint clamp stays close to the workpiece support so that the cavity retaining the non-reactive gas has no large leak when the shield is engaged with the workpiece.
3. An apparatus as in claim 1 in which the workpiece is a semiconductor wafer, and the cavity retains the non-reactive in the vicinity of the circumferencial edge of the semiconductor wafer.
4. An apparatus as in claim 1 further comprising a shield restraint press for pressing on the shield restraint clamp so that the shield is pressing against the portion of the workpiece.
5. An apparatus as in claim 4 in which the shield restraint press employs a spring action for pressing on the shield restraint clamp.
6. An apparatus as in claim 1 further comprising a shield support for supporting the shield so that the shield and the workpiece are spaced apart when the shield is disengaged from the workpiece.
7. An apparatus as in claim 6 further comprising shield aligner connected to the shield and the shield support for aligning the shield with the shield support.
8. An apparatus as in claim 1 further comprising a shield restraint support for supporting the shield restraint clamp so that the shield and the shield restraint clamp are spaced apart when the shield is disengaged from the workpiece.
9. An apparatus as in claim 1 in which the actuator comprises a movable shaft connected to the workpiece support.