Device Photolithography: Reduction Cameras: Mechanical Design of the 3.5Xand 1.4X Reduction Cameras

The 3.5X and 1.4X reduction cameras basically employ the same structural features differing only in the lenses and focal distances required to achieve the desired reductions. Both cameras have been designed as fixed-focus cameras in that no adjustment is made on individual components to optimize the focus and magnification. The camera incorporates the following design features: (i) isolation of the camera from building vibrations; (ii) temperature compensation in the long and short conjugates to compensate for changes in the lens due to changes in the ambient temperature; (Hi) sufficient structural mass of individual components and material conductivity to avoid local distortions due to rapid changes in ambient temperatures; (iv) artwork and image plates automatically positioned to within an accuracy of about one micron; and (v) exposure control which can be varied, with a high degree of reproducibility.