Cerium oxide-based polishing solution for STI structure

By synergistically configuring nano-cerium dioxide abrasives and other components, the balance between oxide removal efficiency and silicon nitride protection in STI structures with cerium oxide-based polishing slurries was solved, achieving high selectivity and good planarization effect.

CN122278356APending Publication Date: 2026-06-26XINGHUA TSINGKE (TIANJIN) ELECTRONIC MATERIALS CO LTD
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Patent Information

Application Number
CN202610416232.8
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2026-04-01
Publication Date
2026-06-26

AI Technical Summary

Technical Problem

Existing cerium oxide-based polishing slurries, when used in the polishing process of STI structures, struggle to balance oxide removal efficiency with silicon nitride layer protection, and are prone to over-grinding of the trench area, affecting planarization results.

Method used

A combination of nano-cerium dioxide abrasive, hydroquinone, pyridine carboxylic acid, D-sorbitol, and 1,2-benzisothiazolin-3-one was used to adjust the pH of the polishing solution to 3-5, thereby creating a synergistic effect that improves the removal rate of the oxide layer and inhibits the removal rate of the silicon nitride layer, thus controlling trench depression.

Benefits of technology

A balance was achieved between high oxide layer removal capability and silicon nitride layer protection, improving the selectivity and planarization efficiency of the STI structure and reducing damage to the trench area.

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Abstract

The invention provides a cerium oxide-based polishing solution for an STI structure, the polishing solution comprises the following components according to the total mass: 0.05 wt% to 5 wt% of nano cerium dioxide abrasive, 0.02 wt% to 0.2 wt% of hydroquinone, 0.05 wt% to 0.25 wt% of picolinic acid, 0.01 wt% to 0.5 wt% of D-sorbitol and 0.001 wt% to 0.01 wt% of 1, 2-benzisothiazolin-3-ketone, and the pH value of the polishing solution is 3 to 5. According to the cerium oxide-based polishing solution provided by the invention, the content of Ce < 3 + > is increased and the removal rate of TEOS is promoted by adding the reducing agent and mildly and finely adjusting the surface activity of CeO2, a relatively high TEOS: Si3N4 selection ratio is obtained under the synergistic effect of the cerium oxide-based polishing solution and other inhibitors and passivators, the removal rate of Si3N4 is inhibited, so that oxides in grooves can be indirectly prevented from being excessively ground, and the polishing effect of the cerium oxide-based polishing solution is improved. And relatively high wafer surface planarization efficiency is obtained.
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