A novel method for photoresist stripping using ozone/de-ionized water chemistry

The mixture of sulfuric acid and hydrogen peroxide (SPM) that is used to strip photoresist from silicon wafers is a widely employed technique in the semiconductor manufacturing. Although these sulfuric acid processes have been used for many years, they also have proven to be costly. This cost is primarily due to the need for frequent bath change-outs and the use of high process temperatures which impose safety and environmental concerns. In response to these drawbacks, the use of a ozone and de-ionized water mixture for photoresist stripping has been investigated. Results show that this technique effectively removes hard-baked resist (ashed and un-ashed) from bare silicon and patterned wafers and produces surfaces with less particles and metals when compared to typical SPM and SOM processes.