Polishing Agent for Semiconductor CMP
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Solution Overview
Problem
Current polishing agents for semiconductor integrated circuits fail to achieve a high selection ratio and satisfactory planarity due to insufficient control over the polishing rate of silicon nitride films, leading to unsatisfactory results in chemical mechanical polishing (CMP) processes.
Innovation Solution
A polishing agent comprising a metal oxide, a water-soluble polyamide with tertiary amino groups and oxyalkylene chains, an organic acid, and water, with a pH of 7 or less, is used to control the polishing rate of silicon nitride films while maintaining a high polishing rate for silicon oxide films, thereby achieving a high selection ratio and improved planarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a polishing agent contains cerium oxide grains and conventional additives (arylamines, heterocyclic amines, aminocarboxylic acids, cyclic monocarboxylic acids, or unsaturated monocarboxylic acids), then the polishing rate of silicon dioxide film can be maintained at a sufficiently high value, but the polishing rate of silicon nitride film is not sufficiently controlled, resulting in insufficient selection ratio and unsatisfactory planarity
Solution Approach 1:
The invention changes the chemical parameters of the polishing agent by replacing conventional additives with a water-soluble polyamide containing specific functional groups (carboxyl, hydroxyl, or amine groups). This parameter change in the additive chemistry selectively modifies the interaction between the polishing agent and silicon nitride film, reducing its polishing rate while preserving the high polishing rate for silicon dioxide film, thereby achieving the desired selection ratio and planarity
Solution Approach 2:
The invention creates a composite polishing agent system comprising cerium oxide abrasive grains combined with a specifically designed water-soluble polyamide additive. This composite material formulation leverages the abrasive action of cerium oxide on silicon dioxide while the polyamide component selectively moderates the interaction with silicon nitride, achieving both high productivity and manufacturing precision simultaneously
2Manufacturing precision
If the selection ratio of silicon dioxide film to silicon nitride film is increased to stop polishing when silicon nitride film is exposed, then a smoother surface can be obtained, but the polishing rate of silicon nitride film must be sufficiently controlled, which conventional polishing agents fail to achieve
Solution Approach 1:
The invention modifies the chemical parameters of the polishing agent by introducing a water-soluble polyamide with specific functional groups that selectively interact with silicon nitride film. This parameter change reduces the polishing rate of silicon nitride film to an appropriate level, enabling precise control of the polishing process to stop exactly when the silicon nitride film is exposed, thereby achieving both high surface smoothness and controlled productivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution effectively achieves a high selection ratio and planarity by regulating the polishing rate of silicon nitride films, ensuring a high polishing rate for silicon oxide films, thus enhancing the CMP process in semiconductor production.
Implementation Method 1
a water-soluble polyamide having a tertiary amino group and/or an oxyalkylene chain in a molecule thereof
Implementation Method 2
an organic acid and water, and having a pH of 7 or less
Implementation Method 3
a particle of a metal oxide... the polishing agent... for chemical mechanical polishing
Implementation Method 4
chemical mechanical polishing (hereinafter, referred to as CMP) method
Data Source
AI summary
A polishing agent includes a particle of a metal oxide, a water-soluble polyamide, an organic acid and water. The water-soluble polyamide has a tertiary amino group and/or an oxyalkylene chain in a molecule thereof. The polishing agent has a pH of 7 or less.