Analyzing the contents of residual and plasma-supporting gases inside a vacuum deposition unit chamber

Abstract

Abstract. The paper describes a quadruple mass-spectrometer method, which is used to analyze the content of residual gas in a vacuum chamber of the ARM NTM (Automatised Working Area) ion-plasma unit. This unit is used to perfect the magnetron deposition process for coating radio-reflecting surfaces. The intake of pure argon into the chamber revealed up to 0.3 % of impurities in the plasma-supporting gas, including 0.02 % of water and oxygen. A significant presence of hydrocarbon gases is explained by the presence of solvents sorbed in rubber washers, joints of internal equipment, and other components inside the chamber. In order to decrease the level of impurities in the plasmasupporting atmosphere inside the chamber and improve the composition and properties of the coatings, it is necessary to take additional measures to cleanse and degas the surface of the chamber from condensation products and hydrocarbon compounds. To provide a minimal level of impurities in the coated surfaces it is vital to clean and degas the surfaces of the chamber, removing residual moisture and hydrocarbon compounds.Target dispersing and coating condensation processes are conducted in a gaseous environment, containing residual components of the vacuum chamber atmosphere. Inleakage, wall desorption, gas emissions from spluttered components and specimens cause the residual atmosphere to intake various chemically active gases, e.g.: water, oxygen, hydrocarbons, hydrogen, and carbon dioxide. The quantity of these elements and compounds depends on a number of factors. In laboratory and industrial apparatuses operating in vacuum not exceeding 10 -4 Pa the sum of partial water, nitrogen, and oxygen pressures normally comprises a greater part from residual gas pressure [1]. The degree of impurities in the plasma-supporting gas depends on the residual gas pressure; it is individual for each vacuum chamber and depends on its state before deposition, along with the properties and amount of components prepared for vacuum depositing and the operating pressure of the plasma during the process of

Analyzing the contents of residual and plasma-supporting gases inside a vacuum deposition unit chamber

“…In comparison we can see that the high quality GOST 10157-79 argon, used in the test has the following percentage of impurities: under 0.0007 % oxygen, under 0.005 % nitrogen, under 0.0009 % water, under 0.0005 % hydrocarbon compounds. The total percentage of argon is over 99.99 % [3]. Thus, the percentage of water and total sum of impurities in the plasma-supporting gas is significantly greater than required by the state standard for argon intake.…”