Pilditrüki

Pilditrüki, also known as photolithography, is a process used in the microfabrication of semiconductor devices and integrated circuits. It is a critical step in transferring geometric patterns from a mask to a light-sensitive chemical called a photoresist on a substrate, typically a silicon wafer. The process begins with coating the wafer with a thin layer of photoresist. A mask, which contains the desired circuit pattern, is then aligned precisely over the photoresist-covered wafer. Next, a light source, usually ultraviolet (UV) light, is shone through the mask. Where the mask is transparent, the light passes through and exposes the photoresist. Where the mask is opaque, the light is blocked.

After exposure, the wafer undergoes a development step. Depending on the type of photoresist used, either the exposed or unexposed areas are selectively removed, leaving a patterned layer of photoresist on the wafer. This patterned photoresist then acts as a stencil. Subsequent processing steps, such as etching or deposition, can be performed on the wafer. The etchant will remove the underlying material only in the areas not protected by the photoresist, or deposition will add material only to the exposed areas. Finally, the remaining photoresist is stripped away, leaving the transferred pattern on the wafer's surface. Pilditrüki is a highly repetitive process, with many layers of different patterns being applied sequentially to build up complex microelectronic devices. Its precision and repeatability are essential for the mass production of modern electronics.