Metal ion removal from photoresist solvents

The trend toward narrower linewidths in the manufacture of integrated circuits has put an ever increasing burden on contamination control in every aspect of semiconductor fabrication. The number of microlithographic steps used in the fabrication of an integrated circuit has increased dramatically with the complexity of today's semiconductor chips. The removal of unwanted particle contamination from the photoresist before application to the wafer surface has been accomplished by filtration at the manufacturer of the photoresist as well as the end user. Metal ions in the photoresist now pose an ever increasing contamination problem with the feature sizes moving toward 0.25 micron and smaller. The removal of unwanted metal ions from the photoresist prior to application of the photoresists to the wafer surface will reduce device defects due to metal contamination. The introduction of a metal ion removal device to reduce the final metal ion content of photoresists will drastically reduce the exposure of the wafer surface to these contaminations. The reduction of metal ion concentration from several hundred ppb to single digit ppb will be demonstrated in single pass application of this device. Utilization of this technology will reduce the incidence of defects during the fabrication of the integrated circuit.