Nanofabrication encompasses a range of advanced techniques used to construct structures and devices with dimensions typically below 100 nanometers, enabling the development of nanoscale technologies across electronics, photonics, medicine, and materials science. Key nanofabrication approaches include top-down methods, such as photolithography, electron beam lithography, and nanoimprint lithography, which pattern nanoscale features onto surfaces using subtractive or pattern-transfer processes. In contrast, bottom-up techniques such as chemical vapor deposition (CVD), molecular self-assembly, and sol-gel synthesis build nanostructures from atomic or molecular components, allowing greater control over material composition and function. Hybrid methods that integrate both strategies are increasingly used to achieve higher precision and scalability. As device miniaturization and complexity advance, nanofabrication remains central to innovations in semiconductors, MEMS/NEMS, biosensors, and quantum devices, driving the future of high-performance and multifunctional nanotechnologies.