Isolation etching method for shallow trench with high depth-to-width ratio

Abstract

The invention provides an isolation etching method for a shallow trench with a high depth-to-width ratio. The method comprises an etching step, and the etching step comprises multiple sub steps, wherein a process parameter value employed by each sub step for changing a deposit accumulation amount of a reaction by-product changes according to a first rule capable of enabling the deposit accumulation amount of the reaction by-product to be successively decreased; or, the process parameter value employed by each sub step for changing the deposit accumulation amount of the reaction by-product changes according to the second rule capable of enabling the deposit accumulation amount of the reaction by-product to alternate between an increasing process and a decreasing process. According to the isolation etching method for the shallow trench with the high depth-to-width ratio, provided by the invention, under the condition that an ideal trench etching morphology is obtained, the etching step can be simplified, etching equipment does not have to be changed, and the manufacturing cost of the equipment can be decreased.

Description

technical field [0001] The invention relates to the technical field of microelectronics, in particular to a high aspect ratio shallow trench isolation etching method. Background technique [0002] In recent years, with the increase in the integration of semiconductor devices, the size of a single element is gradually miniaturized. For the process node of 32nm and below, the shallow trench isolation etching will require a higher aspect ratio. The etching process for etching shallow trenches on a chip has higher requirements, so as to obtain a trench etching morphology with an ideal aspect ratio. [0003] At present, people usually use a continuous etching method to etch the substrate, that is, the total etching depth of the substrate is etched in one step, and by adjusting the excitation power and the flow rate of etching gas (such as HeO) and other parameters to improve the smoothness of the sidewall morphology of the trench. However, when the substrate etching process is ...

AI Technical Summary

Problems solved by technology

[0011] First, due to the complicated etching steps of the above-mentioned etching method, it is easy to cause contamination particles to fall during the entire etching process, thereby causing the substrate to be contaminated, thereby reducing the yield of the product

[0012] Its two, because the protective film formation process of above-mentioned etching method adopts the mode of sputtering to form protective film on the substrate, this way needs to carry out special design to etching equipment, so that it has sputtering function, thus causes the Increased manufacturing costs

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