Cleaning method of chemically and mechanically grinded polycrystalline silicon

Abstract

The invention provides a cleaning method of chemically and mechanically grinded polycrystalline silicon. The cleaning method is characterized by including the steps: cleaning particulate matters; firstly brushing surfaces of wafers by matching ammonium hydroxide serving as a cleaning agent with a brush (Brush 1); secondly brushing the surfaces of the wafers by matching hydrofluoric acid solution serving as a cleaning agent with a brush (Brush 2). Brushing process orders in a conventional cleaning process are adjusted, a brushing procedure of the hydrofluoric acid solution has obvious destructive effect on silicon oxide and is postponed, the working procedure is adjusted, so that the surface of the polycrystalline silicon can be protected by a silicon oxide layer generated in the cleaning process of the particulate matters when being brushed by the ammonium hydroxide, roughened damage to the surface of the polycrystalline silicon caused by corrosion of the ammonium hydroxide is avoided,flow of the hydrofluoric acid solution is decreased in the brushing process of the hydrofluoric acid solution, the hydrofluoric acid solution is decreased, cost is saved, and damage of the hydrofluoric acid solution to the surface of the polycrystalline silicon can be reduced.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a cleaning method after chemical mechanical polishing of polysilicon in the manufacturing process of a 3D NAND flash memory structure. Background technique [0002] With the development of planar flash memory, the production process of semiconductors has made great progress. However, in recent years, the development of planar flash memory has encountered various challenges: physical limits, existing development technology limits, and storage electron density limits. In this context, in order to solve the difficulties encountered in planar flash memory and to seek lower production costs per unit storage unit, various three-dimensional (3D) flash memory structures have emerged, such as 3D NOR (3D or not) flash memory and 3D NAND (3D NAND) flash memory. [0003] At the same time, in order to improve the performance of three-dimensional (3D) flash memory, the size of thre...

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Problems solved by technology

[0012] But in above-mentioned cleaning process, because hydrofluoric acid can destroy the silicon oxide layer that forms in the step (1) and plays a certain protective effect to polysilicon, thereby make in step (3) the surface of polysilicon is directly exposed under the ammoniacal liquor environment, and then Lead to roughness of the polysilicon surface (Roughness) or even damage (Damage)

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