pH-Adjuster Free CMP Slurry Using Chelating Agents
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Solution Overview
Problem
The use of pH-adjusters in chemical mechanical planarization (CMP) slurries increases cost and complexity, and can lead to contamination of metal surfaces, degrading integrated chip performance due to chemical interactions.
Innovation Solution
A pH-adjuster free CMP slurry is formed by using chelating agents to adjust the pH value, which bond to metallic ions, thereby reducing the need for pH-adjusters and minimizing surface contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pH-adjusters are used in CMP slurry, then the pH value can be controlled, but the cost and complexity increase and metal surface contamination occurs
Solution Approach 1:
The patent removes pH-adjusters from the CMP slurry composition entirely, extracting the harmful component while maintaining pH control through alternative means (buffer systems formed by metal ions and water). This resolves the contradiction by eliminating the source of complexity and contamination while preserving the essential pH control function.
Solution Approach 2:
The patent introduces buffer systems as intermediaries between metal ions and water to control pH without direct addition of pH-adjusters. The buffer system mediates the interaction, allowing pH control through the equilibrium of metal ion hydration reactions rather than through direct chemical addition, thereby reducing complexity and contamination risk.
2Manufacturing precision
If pH-adjusters are used in CMP slurry, then the pH value can be adjusted, but chemical interactions that degrade chip performance occur
Solution Approach 1:
The patent extracts pH-adjusters from the slurry composition to eliminate the harmful chemical interactions that cause metal surface contamination. By removing these additives, the patent prevents the degradation of integrated chip performance while maintaining necessary pH control through buffer systems formed by metal ion-water interactions.
Solution Approach 2:
The patent converts the naturally occurring metal ion-water interactions, which were previously considered harmful when combined with pH-adjusters, into a beneficial buffer system. By allowing metal ions to interact with water to form buffers without adding pH-adjusters, the patent transforms a potential source of contamination into a mechanism for pH control that avoids harmful chemical interactions.
3Productivity
If traditional CMP slurry with pH-adjusters is used, then removal rate can be achieved, but cost increases
Solution Approach 1:
The patent removes pH-adjusters from the slurry composition, eliminating the cost associated with these additives while maintaining material removal rate through the buffer system. This extraction of unnecessary components directly reduces slurry cost while preserving the essential polishing functionality.
Solution Approach 2:
The patent enables the slurry to self-regulate pH through buffer systems formed by metal ions and water, eliminating the need for external pH-adjusters. This self-service mechanism reduces material costs while maintaining the removal rate, as the buffer system naturally controls pH without requiring additional chemical additives.
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 solution reduces the cost and complexity of CMP slurries while mitigating chemical interactions that can degrade integrated chip performance, achieving a desired removal rate without the use of pH-adjusters.
Implementation Method 1
A chelating agent configured to bond to metallic ions and adjust a pH value of the CMP slurry from the first pH value to the desired pH value
Data Source
AI summary
The present disclosure relates to a method of forming a CMP slurry that is free of pH-adjusters (i.e., chemicals added solely for the purpose of adjusting a pH of a CMP slurry), and an associated a pH-adjuster free CMP slurry. In some embodiments, the method is performed by forming a CMP slurry having a first pH value. A desired pH value of the CMP slurry is determined. A chelating agent configured to bond to metallic ions is provided to the CMP slurry. The chelating agent is configured to adjust a pH value of the CMP slurry from the first pH value to the desired pH value. By using the chelating agent to adjust a pH value of the CMP slurry to achieve a desired pH value, the method is able to form a CMP slurry that is free of pH-adjusters, thereby reducing the cost and complexity of the CMP slurry.