Types of Resist Materials
There are primarily two types of resist materials:
positive resists and
negative resists. In positive resists, the exposed regions become soluble in a developer solution, while in negative resists, the exposed regions become insoluble.
Positive Resists
Positive resists are designed so that the radiation exposure breaks down the polymer chains, making the exposed regions easier to dissolve in the developer. This creates a direct pattern transfer from the mask to the substrate.
PMMA (Polymethyl methacrylate) is a common example of a positive resist.
Negative Resists
Negative resists work in the opposite manner. Radiation exposure induces cross-linking of polymer chains, making the exposed regions insoluble in the developer. SU-8 is a widely used negative resist, known for its high aspect ratio capabilities in
microfabrication.
Future Perspectives
The future of resist materials in nanotechnology looks promising, with ongoing research focused on developing
next-generation resists that offer better performance, environmental sustainability, and cost-effectiveness. The integration of
self-assembling materials and
smart polymers is expected to bring about significant breakthroughs in the field.
