湿法清洗和蚀刻化学品简单资料全解.ppt

WET ETCH CLEAN Chemical * Page * Page * Differences between 49%HF, HF(50:1) ,DHF(100:1) The Etch rate: 49%HF HF(50:1)DHF(100:1) on the same condition to the same material . In Backside etch , 49%HF is used to etch the nitride on the back side deposited at Diffusion ,which is much thick ,about 1600A. DHF (100:1) Etch rate is the lowest among the three chemicals,so it is used to preclean ,that is to etch a very thin oxide layer. As to oxide etch , HF(50:1) etch rate is in a reasonable range ,so it is suitable to etch oxide layer completely and safely. Page * BOE (Buffered Oxide Etch) NH4F used as buffer agent , F - ion supplier,so the F- concentration keeps stable ,that means the Etch rate keeps stable. Surfactants are often added to improve wetting, based on the capillary mechanism. Benefit compared to DHF: 1) Low selectivity oxide etch ? for DRAM contact pre-clean 2) Prevent photo resist liftoff ? for KV, Dual gate process Page * BOE etch Polymer residue metal metal dielectric There is some Polymer residue after etch ,so Polymer residue needs to be removed with metal and dielectric not been affected . Page * SC1 Components: NH4OH:H2O2:H2O=1:2:$ Temperature: 30C NH4OH:H2O2::H2O=1:2:50 Function: Particle removal NH4OH:H2O2::H2O=1:2:30 Function: PR removal Page * SC1 to remove Particle Oxidation Dissolution Oxidation mechanism Surface etching Electrical repulsion Electrical repulsion mechanism Mechanism: oxidation and electrical repulsion Page * SC2 Components: HCl:H2O2:H2O=1:1:50 Temperature: 30C Function: metal contamination removal Mechanism : SC2 provides a low pH environment. Alkaline ions (Na, K, Li metals), hydroxide of Al, Mg, Fe, Zn (insoluble in NH4OH SC1), and residual trace metal (Au/Cu not completely desorbed by SC1) will be dissolved in SC2. Page * H3PO4 (Phosphoric Acid) Components: H3PO4 Temperature: 160C Function: Nitride strip, ER = 50 A/min Mechanism:Si3N4 +