EXPOSURE OF ADVANCED POSITIVE AND NEGATIVE E-BEAM RESISTS WITH FOCUSED ION-BEAMS

Negative- and positive-tone e-beam resists have been exposed by focuse d beams of Si++ and Be++ ions. The resolution of the negative resist. Shipley SAL601-ER7, was better than 0.2 mum and vertical sidewalls wer e achieved. A dose of 2 X 10(12) ions cm-3 was required to retain the full thickness of the resist after developing. Different postexposure bake (PEB) times and temperatures were examined in this work. A satura tion in resist response was observed at moderately high PEB temperatur es 115-125-degrees-C). This effect has not been reported previously fo r either ion-beam or e-beam exposure. Increases in developing time can increase the sensitivity and the effective contrast of this resist. T he positive-tone resist, OCG Microelectronic Materials P28, is at leas t two to three times more sensitive than PMMA. It also displays a wide range of doses (4-25 X 10(12) ions cm-2) for which positive-tone imag ing is possible. Present results show the resolution of P28 to be at l east 0.3 mum, which is not as fine as that of polymethylmethacrylate ( PMMA). Preliminary results on the behavior of the P28 resist as a mask for silicon etching are presented.