Chemical Mechanical Polishing Composition for Silicon Wafers
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Solution Overview
Problem
There is a need for new chemical mechanical polishing compositions that can achieve a silicon removal rate of ≥300 nm/min for both the first and final polishing steps of silicon wafers, as existing compositions do not meet the stringent requirements for surface perfection and material specifications such as surface metal content, front surface micro roughness, and total particle per unit area.
Innovation Solution
A chemical mechanical polishing composition comprising water, an abrasive, a cation of specific formula, and a quaternary ammonium compound, which adjusts the pH to 9-12, enhancing the silicon removal rate while maintaining stability and minimizing polymer content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional polishing compositions are used, then the polishing process can be performed, but the silicon removal rate is insufficient to meet the requirement of ≥300 nm/min
Solution Approach 1:
The patent modifies the chemical composition parameters by introducing a specific cation (formula I) and piperazine derivative (formula II) to change the removal mechanism and achieve the required silicon removal rate of ≥300 nm/min while maintaining surface quality
Solution Approach 2:
The polishing composition uses a composite formulation combining water, abrasive particles, specific cations, piperazine derivatives, and quaternary ammonium compounds to achieve both high removal rate and surface perfection through synergistic effects of multiple components
2Productivity
If the silicon removal rate is increased to meet the ≥300 nm/min requirement, then productivity improves, but maintaining consistent surface perfection becomes more difficult
Solution Approach 1:
The polishing composition enables continuous polishing of multiple consecutive wafers without significant variation in removal rate, maintaining both high productivity and consistent surface quality through stable chemical-mechanical action
Solution Approach 2:
The composition formulation includes components that respond to polishing conditions and self-regulate to maintain consistent performance across multiple wafers, ensuring stable removal rates and surface perfection
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 composition achieves a stable silicon removal rate of at least 300 nm/min, ensuring high surface perfection and meeting critical material specifications, with the ability to polish multiple consecutive wafers without significant variation in removal rate.
Implementation Method 1
a quaternary ammonium compound... wherein the chemical mechanical polishing composition exhibits a pH of 9 to 12
Implementation Method 2
The silicon wafer is bathed or rinsed in the polishing slurry in combination with a polishing pad which is pressed against the surface of the silicon wafer and rotated such that the abrasive particles in the polishing slurry are pressed against the surface of the silicon wafer under a load
Implementation Method 3
The lateral motion of the polishing pad causes the abrasive particles in the polishing slurry to move across the silicon wafer surface, resulting in wear, or volumetric removal of the material from the surface of the silicon wafer
Implementation Method 4
chemical mechanical polishing of the wafer surfaces with a polishing slurry... exhibits a silicon removal rate of at least 300 nm/min
Data Source
AI summary
A chemical mechanical polishing composition for polishing silicon wafers is provided, containing: water, optionally, an abrasive; a cation according to formula (I); piperazine or a piperazine derivative according to formula (II); and, a quaternary ammonium compound; wherein the chemical mechanical polishing composition exhibits a pH of 9 to 12. Also provided are methods of making and using the chemical mechanical polishing composition.