Fumed Silica Based Ultra High Purity Synthetic Quartz Powder via Sol Gel Process
Fumed silica-based ultra-high-purity synthetic quartz powder was developed via the sol–gel process to apply to quartz wares and quartz crucibles for use in advanced semiconductor processes. The process conditions of preparing potassium silicate solution, gelation, and cleaning were optimized, i.e., the relative ratio of fumed silica (10 wt%) to KOH (4 wt%) for potassium silicate gelation time of three h and cleaning for one h with five wt% HCl solution. It was observed that the gelation time strongly affected the size distribution of the quartz powder; i.e., a longer gelation time led to a larger size (d50) of the synthesized quartz powder: 157 μm for 2 h and 331 μm for 5 h. In particular, it was found that the morphology of the as-synthesized quartz powder greatly depended on the pulverizing process; i.e., the shape of quartz powder was shown to be rod-shaped for the without-gel-pulverizing process and granular-shaped with the process. We expect that the fumed silica-based ultra-high-purity quartz powder with an impurity level of 74.1 ppb synthesized via the sol–gel process is applicable as a raw material for quartz wares and crucibles for advanced semiconductor processes beyond the design rule of 3 nm. For the past several decades, quartz wares for the semiconductor industry, which are made of quartz powder, have been widely used for consumable parts such as quartz crucibles, substrates, tubes, boats, rings, and baths in semiconductor equipment due to their high heat resistance (up to 1600 °C), high optical transmittance for ultraviolet and visible light wavelengths, and low thermal expanding coefficient (0.5 × 10−6/°C). When using such consumable quartz parts for the process equipment, they can easily generate particles and gases of metal impurities when they are exposed to high temperature and -pressure processes  because their raw material is purified from natural rocks with an impurity level of up to 10 ppm in metal ions such as Fe, Al, Ni, and Zn. Recently, since the channel length of metal–oxide–semiconductor field-effect transistors (MOSFETs) has been scaled down to 3 nm to achieve faster speed, lower power consumption, and higher integration density ultra-high-purity synthetic quartz powder with an impurity level of fewer than 100 parts per billion (ppb) in metal ions is essential so that the fabricating devices are not contaminated by metallic impurities generated from such quartz parts during the fabrication process. If you are looking for high quality, high purity, and cost-effective Quartz powder, or if you require the latest price of Quartz powder, please feel free to email contact mis-asia.