Exhaust gas purification device for CVD process

Abstract

The invention relates to an exhaust gas purifying device of a CVD process. The exhaust purifying device of the CVD process comprises a high-temperature reaction barrel (100) for passing the exhaust gas into the high-temperature reaction barrel (100), so as to make the exhaust gas subjected to an oxidation reaction with oxygen in the air; a cooling absorption tower (200) for passing a gas exhausted from the high-temperature reaction barrel (100), and cooling the gas passed into the cooling absorption tower (200) by using a cooling filtrate and filtering particles, a purification adsorption tower (300) for purifying the exhaust gas emitted from the cooling absorption tower(200) and absorbing particles by using the cooling filtrate passed into the purification adsorption tower (300) and hollow spheres, a liquid storage tank (400) for collecting the cooling filtrate to be provided for the cooling absorption tower(200) and the purification adsorption tower (300), and a pump (500) for pumping the cooling filtrate to the cooling absorption tower(200) and the purification adsorption tower (300). With the exhaust gas purifying device of the CVD process, technical effects of small occupation space, high purification efficiency and thorough removal can be obtained.

Description

technical field [0001] The invention relates to a tail gas purification device of a CVD (Chemical Vapor Deposition, chemical vapor deposition) process. Background technique [0002] In the manufacturing process of bipolar integrated circuits and discrete devices, it is necessary to use silane to participate in the reaction of CVD technology to grow silicon dioxide, silicon nitride, and polysilicon and other doped or passivation films. Therefore, the feed gas during the CVD process includes organosilanes, and thus the components of the off-gas also include undecomposed organosilanes. Silane (SiH 4 ) concentration of 5%, 20%, and 100% and other silane. Silane is a colorless, toxic, flammable and explosive gas. The gas is chemically active and easily oxidized. When the concentration of silane reaches 3%, it will burn in the air. [0003] Generally, about 20% to 60% of the silane gas participating in the reaction is discharged from the tail gas of the reaction device. Especi...

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Problems solved by technology

[0008] (1) The purification efficiency of the spray washing type is not high and the purification efficiency is different for different gases, and it cannot effectively remove silane, borane, phosphine, and arsine in the tail gas at the same time;

[0009] (2) In order to improve the purification efficiency, the device is bulky and occupies the space of the purification delivery room;

[0010] (3) Silane, borane, phosphine, and arsine are adsorbed by filling hollow spheres, so the total amount of adsorption is limited. Once the liquid is adsorbed, the purification efficiency drops sharply

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