The role of metal induced oxidation for copper deposition on silicon surface

Cu deposition behavior onto Si surfaces was investigated as a function of dipping time in various chemical solutions. It shows the progressive phenomena for Cu deposition onto Si surfaces from the initial reaction to final equilibrium state so that we can interpret the different Cu deposition behavior in solutions by evaluating chemical nature, Cu dissolution effect, Cu particle growing effect, chemical oxidation, and metal induced oxidation (MIG) which take place in Cu deposition process. In this work, we categorize the Cu deposition process into three stages such as initial stage, progressive stage, and equilibrium stage. The different initial behavior of Cu deposition is explained by the different ionic strength of chemicals that is mainly attributed to mass transport. Cu particle growth is a main cause of Cu deposition with high concentration and determined on the base of the relation between Cu particle growth rate and dissolution rate depending on pH and redox potential values of chemicals. Oxide formation due to chemical oxidation and metal induced oxidation hinders Cu deposition and metal Cu particle growth and it causes the Cu deposition to be saturated with a self-limiting effect. We found that the critical hindrance oxide thickness for Cu deposition and Cu particle growth is about 3 Angstrom at which one monolayer transition layer of silicon dioxide is estimated. Consequently, we modeled Cu deposition behavior in various solutions as a function of dipping time.