Preparation of deep grooves

Abstract

A deep slot preparation method includes: forms at least one slot on the base board; forms a layer with nitrogen at the inside wall of the slot; forms several crystal grains that cover on the part surface of the layer with nitrogen; forms the oxide layer with phosphorus on the surface of the layer with nitrogen, translates the oxide layer with phosphorus into the etching liquid in order to wipes off the layer with nitrogen without cover the crystal grains. The layer with nitrogen can be the nitrogen silicide layer, the oxide layer with phosphorus can be the borosilicate glass layer or the phosphosilicate glass layer. The method can put the base board in the steam environment, the oxide layer with phosphorus can react with the steam to create phosphoric acid that can etches the layer with nitrogen.

Description

technical field [0001] The invention relates to a preparation method of a deep trench, in particular to a preparation method of a deep trench which has a relatively large inner surface area and can be applied to a high-integration dynamic random access memory. Background technique [0002] Capacitors of DRAM can be divided into two types: stack type and deep trench type. Stacked capacitors are formed on the surface of the silicon substrate, while deep trench capacitors are formed inside the silicon substrate. In recent years, the integration level of DRAM has increased rapidly with the innovation of semiconductor process technology, and in order to achieve high integration level, the size of transistors and capacitors must be reduced. Since the capacitance value of a capacitor is proportional to the surface area of ​​its electrode plate, reducing the size of the capacitor will lead to a decrease in the capacitance value, which is not conducive to the correct interpretation ...

AI Technical Summary

Problems solved by technology

[0008] The main purpose of the present invention is to provide a method for preparing deep trenches with a large internal surface area that can be applied to highly integrated dynamic random access memories, which utilizes an etchant produced by the reaction of a phosphorus-containing oxide layer with water vapor Remove the nitrogen-containing layer in the bottom half of a deep trench, thus solving the problem that traditional etching solutions are difficult to transport to the bottom half of the deep trench

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