Silicon through hole barrier layer alkaline polishing solution

Abstract

The invention relates to a silicon through hole barrier layer alkaline polishing solution, which comprises glycine, arginine and an azole compound, wherein the addition mass of the arginine is at least one time of the addition mass of the glycine, the arginine contains guanidyl, and when the guanidyl in the arginine is combined with the azole compound for use, the removal rate ratio of tantalum to copper is adjusted. According to the invention, the molecular structure of arginine contains amino and hydroxyl to provide chelation, the arginine contains guanidyl and is alkaline amino acid, the arginine is used as a rate improver of tantalum to accelerate removal of tantalum, the removal rate selection ratio of metal tantalum and copper is adjusted by adjusting the content of the guanidyl in the arginine, and the azole compound acts with the amino and the hydroxyl and also acts with the guanidyl, so that the azole compound not only can play a role in corrosion inhibition of metal copper, but also can play a good role in correcting the dish-shaped pit.

Description

technical field [0001] The invention relates to an alkaline polishing solution for a through-silicon hole barrier layer. Background technique [0002] In recent years, the market of 2.5DIC and 3DIC has become larger and larger, one of the main reasons is the rapid development of through-silicon via technology (ThoughSilicon Via, TSV). The TSV copper film is removed by chemical mechanical polishing (CMP), leaving only the copper in the through hole. In order to prevent copper from diffusing to the substrate to form high-resistance copper silicide, and to solve the problem of Cu and dielectric layer SiO 2 For problems such as poor adhesion, metal titanium, tantalum, or titanium nitride and tantalum nitride are often used as barrier layers between the copper layer and the isolation dielectric layer, which need to be removed in CMP; and in the process of barrier layer polishing At the same time, the isolation layer silicon dioxide needs to be removed, and stop at Si 3 N 4 la...

AI Technical Summary

Problems solved by technology

However, with the development of microelectronics technology nodes, the barrier layer polishing solution is gradually changed to a weakly alkaline environment. Organic quaternary ammonium salts are cationic surfactants, which are mainly suitable for acidic environments. If used in alkaline environments, they will destroy secondary The stability of the electric double layer of silica colloidal colloids will cause colloidal agglomeration, severe scratches on the wafer surface, and lower yields. In order to increase the rate of barrier layer tantalum, imine, hydrazine, and guanidine are added. It can exist stably, but under alkaline conditions, imine, hydrazine, and guanidine are unstable, and are easily hydrolyzed into ammonia and urea, and guanidine, hydrazine, and imine are all highly toxic, and hydrazine is extremely toxic and explosive. Not conducive to environmental protection