Photolithography technology in electronic fabrication

The paper introduce the photolithography technology.First, the writer explain the process of photolithography.a modern wafer (form IC) will go through a photolithography cycle up to 50 times, some 100 times more.then, the article illustrate photoresist , photoresists are classified two groups :positive resist and negative resist.another important technology is photomask, it is the mass production of IC device,worldwide photomask market was estimated as 3.2 billion in 2012.at the last ,the paper introduce the photolithography machine(tools).The newest feature size of photolithography machine will bring us to 12nm time, maybe 2016. Photolithography technologyPhotolithography, also termed optical lithography or UV lithography, is a process used in microfabrication to pattern parts of a thin film or the bulk of a substrate.It uses light to transfer a geometric pattern from a photomask to a light-sensitive chemical "photoresist", or simply "resist," on the substrate.A series of chemical treatments then either engraves the exposure pattern into, or enables deposition of a new material in the desired pattern upon, the material underneath the photo resist.For example, in complex integrated circuits, a modern CMOS wafer will go through the photolithographic cycle up to 50 times.Simplified illustration of dry etching using positive photoresist during a photolithography process in semiconductor microfabrication (not to scale).A single iteration of photolithography combines several steps in sequence.Modern cleanrooms use automated, robotic wafer track systems to coordinate the process.The procedure described here omits some advanced treatments, such as thinning agents or edge-bead removal.[1]