ABSTRACT
Particle control in high-purity chemicals has become a major concern in the past 3 to 5 years as the electronic industry progressed toward 256K to 4M memory devices with smaller line widths and larger chip sizes. Particles and dissolved metals in chemicals cause special concern because their diffusion into the silicon substrate can cause changes in electrical properties. Maximum concentrations for a wide range of metallic impurities have been incorporated by some of the major chemical suppliers in their low particle-grade chemicals. Quality control and Statistical Process Control (SPC) programs are being incorporated in chemical manufacturing and packaging processes to ensure that product quality meets new rigid specifications incorporated by aggressive chemical suppliers. High-purity filtered demineralized water must be used to clean containers for packaging. Bulk transfer systems used to load or unload bulk chemicals are subject to the same factors affecting chemical purity in trailer tankers and rail cars.
