Semiconductor device etching method and semiconductor device formation method

Abstract

The invention provides a semiconductor device etching method and a semiconductor device formation method. The semiconductor device etching method comprises a main etching process and at least one auxiliary etching process. The main etching process comprises steps of forming a polycrystal layer on an oxide layer on a stratum basale of a semiconductor device, performing etching on the polycrystal layer through a first etching fluid, and finishing the main etching flow and leaving a first preset thickness on the polycrystal layer when a preset first etching end point detection condition is met. The auxiliary etching process comprises steps of performing the etching on the residual polycrystal layer through a second etching fluid, wherein the etching speed of the second etching fluid is slower than that of the first etching fluid, finishing the auxiliary etching process when the preset second etching end point detection condition is met and leaving a second preset thickness on the oxide layer. The semiconductor device etching method increases the adjustable range of the etching amount of the oxide layer without changing the main etching process, and the adjustment of the thickness of the lower oxide layer does not affect the etching feature.

Description

technical field [0001] The invention relates to the technical field of semiconductor technology, in particular to a method for etching a semiconductor device and a method for forming a semiconductor device. Background technique [0002] In the polysilicon etching process, the main etching step (MainEtching) usually uses EPD (Etching Endpoint Detection) method plus a certain amount of overetching to ensure that the silicon is etched clean, and the etching characteristics of the main etching step also fix the oxide on the lower layer of the semiconductor device. The thickness of the layer (under-layerOxide or ONO). [0003] In the existing semiconductor manufacturing (FAB) etching process, although there is a function of adjusting the etching range of the oxide layer by adjusting the end point detection method, the adjustable range is too small and only (ie "Angstrom", 10 to the negative 10th power meter), very limited; and if the thickness of the oxide layer is adjusted by ...

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Problems solved by technology

[0004] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a semiconductor device etching method and forming method to solve the above-mentioned problem of poor etch adjustability

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