EFFECT OF CYLINDRICAL SPOT SHAPE IN GAS PLASMA SOURCES FOR X-RAY-LITHOGRAPHY

The effect of an x-ray emitting spot with cylindrical symmetry in gas plasma sources is studied using the XMAS x-ray lithography program tak ing into account variations of x-ray illumination on the exposed wafer . These divergence effects may affect the process latitude across the exposure field. Maximum limits in the dimensions of the cylindrical x- ray source are determined using the XMAS simulation. The effective x-r ay source size of the Science Research laboratories plasma source was measured using the appropriate filters to simulate x-ray lithography. The experimental results indicate that no adverse divergence effects s hould be expected in a 4.4 cm diameter exposure field at 63.5 cm from the source.