Micro Electronics Processing Lab Wet and Dry Oxide Growth Team 1B Sudipta Bera Matthew Berg Cooper Swenson Glenda Anderson Dana Olson
Introduction ► RCA Clean ► Theoretical Oxide Thickness Calculated ► 2 Different Sets of Data Group 1BGroup 2B
Concentration Gradient In Furnace Gas Inlet Wafer Position 4 Wafer Position 3 Wafer Position 2 Wafer Position 1 Front Of Furnace Concentration of oxidizing gas decreases as it reacts with Silicon surface C A inlet C A outlet C A inlet C A outlet >
Results Theoretical Thickness 530 A
Results Theoretical Thickness 1250 A
Diffusion Of Gas Si SubstrateSiO 2 Diffusion of O 2 or H 2 O Stagnant Gas Layer
Results Theoretical Thickness 5299 A
Results Theoretical Thickness 6610 A
Conclusions ► Temperature and Oxidant Effects ► Position in Furnace has Large Impact on oxide thickness ► Random Growth on Wafers ► Variations From Theoretical Calculations Group B1Group B2 Theoretical Average (Dry)(Wet) (Dry)(Wet)
Variation Of Oxide Thickness On Wafer Wafers have thin initial layer of oxide before heating. During heating, oxidizing gas will diffuse through initial layer and grow in non-uniform manner. Regions of thin initial oxide layer will grow fastest and regions of thick initial oxide layer will grow slowest. Variations in thickness for wet oxide are greater than dry oxide due to faster diffusion rate of H 2 O.
Average Thickness On Wafer – Group 2B Wet Oxide
Average Thickness On Wafer – Group 2B Dry Oxide