X-RAY MASK TEMPERATURE DISTRIBUTION AND MAGNIFICATION CONTROL

The fabrication of X-ray masks may leave a nonuniform stress distribut ion in the membrane, thus leading to placement errors when the circuit pattern is transferred to the device wafer. In general, these intrins ic errors include magnification. Additionally, other extrinsic effects can introduce independent distortions. One of the possible extrinsic sources of distortion is the temperature distribution within the membr ane resulting from the energy absorbed from the X-rays. The physical p rocess during exposure needs to be carefully analyzed in order to cont rol and minimize error during pattern transfer.