CONTROLLED ETCHING OF SILICON IN THE HF-HNO3 SYSTEM
CONTROLLED ETCHING OF SILICON IN THE HF-HNO3 SYSTEM
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DOI：
10.1149/1.2425322
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发表时间：
1962-01-01
影响因子：
3.9
通讯作者：
DSTEFAN, DJ
中科院分区：
文献类型：
--
作者：
KLEIN, DL;DSTEFAN, DJ
Some of the important factors that affect the degree of reproducibility of desired dimensions, flatness, and surface finish of chemically etched silicon have been investigated. The etching rate of single crystal silicon in hydrofluoric and nitric acids was studied as a function of the ratio of the concentrated acids, temperature, and stirring rate. These variables were found to be related to the etching rates over the ranges studied. No difference in etch rate was observed for n, p and np junction silicon, ranging in resistivity from 0.05 to 78 ohm-cm. The etch rate appears to be dependent on the diffusion of the fluoride species to the silicon surface in the nitric acid-rich region. The controlled etching technique has been applied to the etch-cutting of wafers from selectively masked silicon slices. Preliminary investigation has shown that this method is applicable for the preparation of slices for diffusion processing.With the more sophisticated semiconductor devices now under development, dimensional control is becoming increasingly important. Regulation of the flatness and surface finish as well as the size of wafers and mesas require close dimensional control. Silicon shaping processes now generally employ abrasive cutting and polishing techniques which are known to introduce surface damage. Therefore, devices must be etched following abrasive shaping to remove this damage. Final control of dimensions must then logically lie in the regulation of the etching process. Direct etch-cutting makes it possible to produce devices with surfaces approaching the degree of perfection inherent in the bulk material. In order to achieve control of chemical etching, it is necessary to understand the important variables involved and their effects on the kinetics of silicon dissolution. The variables investigated and reported in this paper include etch composition, temperature, and stirring as they were observed on n, p, and junction-containing material over wide resistivity ranges. Additionally, some factors which affect the degree of roughness and the flatness of surfaces were examined.
