Method for forming grid side wall layer

Abstract

The invention discloses a method of forming a grid wall layer, including the following steps that: a substrate with at least a grid is provided; the method of atomic layer deposit is utilized to form a complex medium layer in the substrate; a side wall layer is formed in the grid by etching the complex dielectric layer. The invention is not only favorable to improve the performance of the parts with lower heat budgeting, but also improves the uniformity of the performance of the parts with better uniformity of the formed grid side wall layer.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for forming a gate sidewall layer. Background technique [0002] The gate sidewall spacer is generally composed of silicon oxide / silicon nitride (ON) dielectric film or silicon oxide / silicon nitride / silicon oxide (ONO) dielectric film combination. [0003] figure 1 It is a schematic cross-sectional view of a device with an ON structure gate sidewall layer. like figure 1 As shown, an isolation trench 102 is formed by etching and filling between each device of the substrate, and a gate silicon oxide layer 103 (Gate Oxide) is deposited on the silicon substrate 101; by depositing and etching polysilicon, on the substrate The gate 104 is formed; on the substrate on both sides of the gate, there is a lightly doped region 110 (LDD, lightly doped drain) formed by shallow ion implantation using the gate as a mask; Dry etching forms a gate sidewall layer co...

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Problems solved by technology

However, the thermal expansion coefficient of the silicon nitride sidewall formed by this method is quite different from that of polysilicon, and it is easy to crack due to temperature rise and fall during the process, and fall off from the polysilicon gate.

In addition, although the deposition temperature of this method is lowered, due to the use of silane (SiH 4 ) or dichlorosilane (SiH 2 Cl 2 ) The deposition rate of the reaction source is low, the required deposition time is long, and the advantages in terms of thermal budget are not outstanding

Moreover, practice has shown that the quality of silicon nitride films grown by this method is not good enough

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