The effect of dilute cleaning and rinsing chemistries on transition metal removal and si surface microroughness

We use synchrotron radiation total-reflection x-ray fluorescence (SR-TXRF) to determine the efficiency of several dilute cleaning and rinsing chemistries in removing surface transition metal contamination down to 8x10(7) atoms/cm(2) concentration levels from both hydrophilic and hydrophobic silicon surfaces. The dilute chemistry investigated in this work includes HF, HCl, an HF and HCl mixture, DI(HCl), and DI(O-3). The changes in surface roughness are determined by atomic force microscopy (AFM). From these experiments, we conclude that the best results can be obtained by use of a dilute HF-only or an (HF+HCl) process scheme. Incorporation of HCl into the process scheme can result in higher residual Cu levels and increased surface roughness. The use of an ozonated rinse offers no appreciable advantage with respect to metal contaminant removal.