Electrostatic charges on silicon wafers: modeling and neutralization

Context

Wet surface treatments account for more than one-third of the manufacturing steps involved in producing microchips. Cleaning silicon wafers requires the use of chemicals followed by rinsing with deionized water. When this water flows over the insulating (dielectric) layers of the wafers, it can generate electrostatic charges due to friction. If these charges become too strong, they can damage the electronic devices.

Objectives of the thesis

There are three objectives.

1. Model the generation of electrostatic charges during rinsing.
2. Couple this model with an existing fluid dynamics model of the industrial manufacturing process. The ultimate goal is to predict the level of electrostatic charges at any point on a silicon wafer throughout the industrial process.
3. Study methods for neutralizing surface and buried electrostatic charges. Three techniques will be considered: UV-induced photoionization, thermal treatment, and the use of conductive liquids.

Location of the thesis

The thesis will be a collaboration between LIPhy (UGA, CNRS, Grenoble) for the research work (experiments, modeling/simulations) and STMicroelectronics (Crolles, 38920) for the application to industrial processes.

Desired Profile

Master’s 2 student or engineering school student (Materials, Physics, Fluid Mechanics, or a related field). Must be self-motivated and have strong communication skills to work between the LIPhy laboratory and the STMicroelectronics industrial site. Interest in modeling and numerical simulation. Good level of English.