Analysis of the application of ultrapure water in the field of optics
Author: Chengdu Down Corning Science and Technology Development Co., Ltd.
The purity of ultrapure water has become one of the important factors affecting the quality of optical components, production yield and production cost. Therefore, the requirements for water quality in the optical field are also increasing. At the same time, the performance of ultrapure water equipment directly affects the quality of ultrapure water.
· In production, ultrapure water is mainly used for pure water cleaning and pure water dosing. The use of pure water in different process production and the requirements for water quality are also different. Purification requires pure water. If the water contains chloride ions, the capacitor will leak. In the production of electron tubes, the cathode of the electron tube is coated with carbonate, and if impurities are mixed therein, it will affect the emission of electrons, thereby affecting the amplification performance and life of the electron tube.
· Therefore, the liquid should be pure water. In the production of kinescope and cathode ray tube, the inner wall of the fluorescent screen is sprayed or precipitated with a layer of fluorescent material. It is a phosphor particle composed of zinc or other metal sulfide. Potassium silicate is bonded, and it needs to be pure water. If the copper content in pure water is above 8ppb, it will cause luminescence discoloration; if the iron content is above 50ppb, it will make the luminescence discolor, darken and flash jump; Organic colloids, particles, bacteria, etc., will reduce the strength of the fluorescent layer and its adhesion to the glass bulb, and will cause waste, such as bubbles, traces, and light leakage spots.
· In the production of transistors and integrated circuits, pure water is mainly used to clean silicon wafers, and a small amount is used for chemical liquid preparation, water vapor source for silicon wafer oxidation, cooling water for some equipment, and plating solution. The product quality of integrated circuits and the rate of production yield are very large. Alkali metals (K, Na, etc.) in water can cause poor pressure resistance of insulating films, heavy metals (Au, Ag, Cu, etc.) can reduce the withstand voltage of PN junctions, and Group III elements (B, Al, Ga, etc.) will make N-type Deterioration of semiconductor characteristics, V group elements (P, As, Sb, etc.) will deteriorate the characteristics of P-type semiconductors. Phosphorus (about 20-50% of ash) of high-temperature carbonization of bacteria in water will cause localized areas on P-type silicon wafers. Changes in N-type silicon lead to deterioration of device performance Particles (including bacteria) in the water, such as suction on the surface of the silicon wafer, can cause short circuits or poor characteristics.
Montreal Shantou Food Co., Ltd , https://www.montrealsnack.com