WAFER SCRUBBER TEST METHOD
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2001-Nov-19
The failure of a wafer scrubber to remove surface contamination from a wafer can cause catastrophic contamina- tion effects such as reduced yields. The test disclosed below measures the effectiveness of a wafer scrubber in remov- ing contamination and can serve as an early warning system to let an operator know that a wafer scrubber is failing. In the present test, clean wafers are evaluated using a particle detector such as a Tencor 4500 to obtain background counts. The wafers are then inoculated with particles from a clean room swab in an alternating pattern on the wafer. The particles are again counted on the particle detector and data histograms are plotted. The wafers are then cycled through the wafer scrubber and the particles are then recounted and plotted. A removal rate can be calculated from the difference in the two counts divided by the "after contamination" counts.