**2.6. Photolithography**

This is a technique that is used in microfabrication to pattern thin films and bulk materials. Light is being used to transfer pattern onto the light-sensitive photoresist. Photoresist basically is a light-sensitive material, which is used to form pattern coating on the surface. Photoresist is of two types, which are as follows:


Then, etching is done to form patterned hierarchical 3D structures. When photopositive resist coating is done over the substrate, then the growth of structure takes place on the same area where we seed/coat the material. The mask contains the exact copy of resist, which we deposit on the substrate and vice versa. **Table 7** shows features of structures prepared via photolithography technique.
