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Safety and Health Implications of Dry Chemical Etching.

Mueller-MR; Kunesh-RF
Hazard Assessment and Control Technology in Semiconductor Manufacturing, Lewis Publishers, Inc., Chelsea, Michigan 1989:179-201
The use of plasma assisted etching appeared to be an advancement in safety over the wet chemical etching previously used in the semiconductor industry. This newer method has been developed for the etching of nearly all materials used in semiconductor device fabrication. The product of the etching reaction is usually a chlorinated or fluorinated compound of the material being etched. However, due to the reactivity of the ions and radicals formed in the plasma, numerous side reactions can be expected to occur. Products of the etching reaction exit the reaction chamber through a mechanical vacuum pump. Sampling of surfaces within the reaction chamber and air sampling during tool operation and maintenance were taken at a semiconductor facility. A listing was provided of the chemicals found in the effluent gas analysis, in surface and debris analysis, in the analysis of the vacuum pump oil, and in the industrial hygiene air sample analyses. All surface and debris samples from systems using a chlorine based chemistry contained water soluble chlorides. All samples from tools using fluorine based chemistry showed the presence of free fluorides. Solids which tend to accumulate in mechanical vacuum pumps included hexafluoro and hexachloro silicate compounds which present potential contact hazards. Air samples taken during oil and filter changes showed outgassings of fluorides, chlorides, and cyanogen-chloride (506774). During normal production activities involving the loading and unloading of wafers from the reaction chamber, personal exposures to hydrochloric-acid (7647010) and hydrofluoric-acid (7664393) were less than 10 percent of the threshold limit ceiling values. No analyses indicated exposures of any worker to any chemical which exceeded even 20 percent of the recommended limitations. The only exception was cyanogen-chloride exposure to the aluminum etchers.
Air-quality-monitoring; Semiconductors; Electronics-industry; Air-sampling; Control-technology; Toxic-gases; Safety-practices;
506-77-4; 7647-01-0; 7664-39-3;
Publication Date
Fiscal Year
Priority Area
Control Technology and Personal Protective Equipment; Research Tools and Approaches; Control-technology;
Source Name
Hazard Assessment and Control Technology in Semiconductor Manufacturing, Lewis Publishers, Inc., Chelsea, Michigan
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division