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The development of high-powered blue and UV LEDs has enabled the creation of full-color LED TV displays, as well as white LED automotive and domestic lighting. These LEDs are based on Gallium Nitride, which is deposited on substrate wafers supported by CVD SiC-coated graphite susceptor using the MOCVD process.

The history of silicon carbide (SiC) dates back to 1891, when Edward Goodrich Acheson accidentally discovered it while attempting to synthesize artificial diamonds. Acheson heated a mixture of clay (aluminosilicate) and powdered coke (carbon) in an electric furnace. Instead of the expected diamonds, he obtained a bright green crystal adhering to the carbon. This crystal had a hardness second only to diamond, and was thus named carborundum. In 1904, French-Jewish chemist Henri Moissan discovered rare natural silicon carbide minerals while studying meteorite samples from the Diablo Canyon in Arizona, USA. He named these minerals moissanite, and his discovery earned him the 1906 Nobel Prize in Chemistry.

Currently, many semiconductor devices employ mesa device structures, which are predominantly created through two types of etching: wet etching and dry etching. While the simple and rapid wet etching plays a significant role in semiconductor device fabrication, it has inherent drawbacks such as isotropic etching and poor uniformity, which result in limited control when transferring small-sized patterns. Dry etching, however, with its high anisotropy, good uniformity, and repeatability, has become prominent in semiconductor device fabrication processes. The term “dry etching” broadly refers to any non-wet etching technology used for removing surface materials and transferring micro and nano patterns, including laser etching, plasma etching, and chemical vapor etching. The dry etching discussed in this text specifically pertains to the narrow application of processes using plasma discharge—either physical or chemical—to modify material surfaces.

Gallium Nitride (GaN) epitaxial wafer growth is a complex process, often utilizing a two-step method. This method involves several critical stages, including high-temperature baking, buffer layer growth, recrystallization, and annealing. By meticulously controlling the temperature throughout these stages, the two-step growth method effectively prevents wafer warping caused by lattice mismatch or stress, making it the predominant fabrication method for GaN epitaxial wafers globally.

In semiconductor manufacturing, the precision and stability of the etching process are paramount. One critical factor in achieving high-quality etching is ensuring that wafers are perfectly flat on the tray during the process. Any deviation can lead to uneven ion bombardment, causing undesirable angles and variations in etching rates. To address these challenges, engineers have developed Electrostatic Chucks (ESCs), which have significantly improved etching quality and stability. This article delves into the design and functionality of ESCs, focusing on one key aspect: the electrostatic principles behind wafer adhesion.

A Dummy Wafer is a specialized wafer utilized primarily to fill machine equipment during the wafer manufacturing process.