Etching methods for semiconductor structures

Abstract

The present invention provides an etching method for a semiconductor structure, including providing a semiconductor structure, the semiconductor structure comprising a substrate and a UTM stack on the substrate, the UTM stack comprising a first low-voltage layer formed on the substrate in sequence A dielectric oxide layer, a second low dielectric oxide layer and an etch stop layer; a patterned photoresist layer is formed on the UTM stack, and the light transmittance of the photoresist layer is collected; the UTM stack is subjected to main etching and etching Etch the second low-dielectric oxide layer and stop at the first low-dielectric oxide layer; substitute the transmittance into the over-etching equation to obtain the over-etching process parameters and feed them back to the process chamber to over-etch the UTM stack so that the The etch stops at the etch stop layer. The semiconductor structure etching method provided by the present invention obtains the over-etching equation by fitting the relationship between the light transmittance of different semiconductor structures and the over-etching process parameters, so as to calculate and adjust the time when the semiconductor structure is over-etched. process parameters, thereby improving the etching accuracy of the semiconductor structure.

Description

technical field [0001] The present invention relates to the technical field of semiconductors, and in particular, to a method for etching a semiconductor structure. Background technique [0002] In the integrated circuit production process, the back-end copper interconnection will be applied to the etching process of the ultra thick metal layer (UTM). The etching process of the UTM has higher requirements on the etching selection ratio and uniformity. High difficulty. During the UTM etching process, the loading effect between different semiconductor structures needs to be considered, otherwise, punch through of the semiconductor structure due to over-etching or metal metal due to insufficient etching of the semiconductor structure will occur. Line disconnection etc. In the prior art, endpoint monitoring (EPD) is usually used to detect the etching of UTM, and the corresponding emission spectra (OES) generated by chemical changes of different dielectric layers of the semicon...

AI Technical Summary

Problems solved by technology

[0003] However, when the light transmittance of the semiconductor structure is too large or too small, the EPD cannot accurately obtain the etching situation of the semiconductor structure, resulting in excessive or insufficient etching.

Images