STUDY OF THE DISTORTED LAYER STRUCTURE OF SILICON WAFERS BY THE METHOD OF PLASMA-CHEMICAL ETCHING AFTER MECHANICAL MACHINING PROCESSES

Document Type: Regular Paper

Authors

1 Faculty of physics, Tabriz University, Tabriz, I. R. of Iran, 51664

2 National Academy of Sciences, Azerbaijan Republic

Abstract

In this experimental work, by using the method of plasma-chemical etching, we have dealt
with the causes of the creation of a distorted layer on the surface of silicon wafers during mechanical
machining processes, in addition, the elucidation of connections between the structure of this layer and
characteristic parameters of the mechanical strength of these wafers have been studied. Experimental
results obtained at room temperature show that after cutting and grinding processes, the mean value of
mechanical strength σ, which is apparently independent of the types of conductivity, is significantly
lower than its theoretical value. Analysis of the dependence of mechanical parameters on the time of
plasma-chemical etching indicates that the lower values obtained for the mechanical strength of silicon
wafers is basically due to the existence of a distorted layer and corresponding internal stresses created on
the surface of these wafers after mechanical machining. Plasma-chemical etching leads to an increase in
σ value. Dependency of σ on the etching time is qualitatively described by the microstructure of the
distorted layer and parameters of the micro relief surface of the wafers. Correlation between parameters
σ, H, K and the microstructure of the distorted layer allows us to suggest the method of plasma chemical
etching as a method of investigating the microstructure of the distorted layer after the mechanical
machining processes.

Keywords