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US 4,785,192 AGranted
Maintaining optical signals in prescribed alignment with respect to workpiece in movable equipment
AssigneeAmerican Telephone and Telegraph Company, AT&T Bell Laboratories
InventorJohn H. Bruning
Life of this patent
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Abstract
A deep-UV step-and-repeat photolithography system includes a narrow-bandwidth pulsed excimer laser illumination source and an all-fused-silica lens assembly. The system is capable of line definition at the 0.5-micrometer level. One significant feature of the system is its ability to perform wafer focus tracking by simply changing the frequency of the laser.
Claims13
An optical system, comprising:
- a source of electromagnetic radiation;
- equipment, including apparatus adapted to support a workpiece, said apparatus being physically separated from said source and said equipment being characterized by an axis which is nonparallel to a surface of said apparatus;
- directing means for directing at least a portion of the radiation emitted by said source to said workpiece, said directing means including aligning means for maintaining a desired alignment between the directed radiation and said axis even during relative motion between said source and said equipment.
A method for fabricating a device, comprising the steps of:
- mounting a workpiece on an apparatus adapted to support such a workpiece, said apparatus constituting a component of equipment characterized by an axis which is transverse to a surface of said apparatus;
- directing electromagnetic radiation from a source of such radiation to said workpiece, said source being physically separated from said apparatus;
- maintaining a desired alignment between said directed radiation and said axis even during relative motion between said source and said equipment;
- an
- further processing said workpiece to complete the fabrication of said device.
2 more elements
Dependencies are inferred from the claim text.