Common Semiconductor Quartz Components and Applications

Quartz belongs to trigonal crystal system, which is a three-dimensional framework mineral crystal composed of silicon dioxide. Typically, pure quartz is colorless and transparent, but it takes on a variety of hues as a result of trace pigment ions, finely dispersed inclusions or the formation of color centers. With multiple excellent properties, quartz is widely appiled in various processes of semiconductor manufacturing, and its performance and quality directly affect the yield, performance, and cost of semiconductor devices.

1. Quartz Crucible

The quartz crucibles are used to hold the polycrystalline silicon raw materials in the high-temperature monocrystalline silicon growth process. To ensure stable support materials, quartz crucibles need to boast excellent high-temperature stability (melting point >1700℃) and a low thermal expansion coefficient to withstand the challenges of harsh high-temperature operating conditions. Quartz crucibles for semiconductor applications need to be manufactured from high-purity quartz of grade 4N8 or higher. This wise material selections can effectively lower the crystal contamination risks caused by impurity precipitation from the quartz crucible due to high-temperature.

Quartz furnace tubes usually serve as the high-temperature reaction chambers for various wafer manufacturing processes such as diffusion, oxidation, and chemical vapor deposition (CVD). So quartz furnace tubes need to feature excellent high-temperature resistance to prevent them from deforming or softening caused by high-temperature environments. In some processes, dehydroxylation treatment is even required to reduce the impact of hydroxyl groups on thermal stability. The manufacture of quartz furnace tubes also requires high-purity quartz material with a metallic impurity content ≤1 ppm to prevent impurities from precipitating during the reaction process and affecting wafer processing results.

Quartz boats are typically used in conjunction with quartz furnace tubes for carrying and transporting dozens to hundreds of wafers. Therefore, quartz boats usually need to possess the same excellent high-temperature resistance, corrosion resistance, and stable, reliable performance in terms of mechanical strength as quartz furnace tubes.

Quartz focus rings are specially designed for dry etching processes. They are typically installed around wafers to confine and homogenize plasma, effectively ensuring uniformity of etching rate and patterning on the wafer. This operating environment requires quartz focus rings to possess strong resistance to plasma corrosion, extremely high dimensional accuracy, and a smooth surface finish to prevent abnormal discharges or particle generation.