Copper-Ruthenium CMP Slurry for Clean Pad High-Rate Polishing
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Solution Overview
Problem
Existing chemical-mechanical polishing (CMP) processes for substrates containing copper and ruthenium face challenges with debris accumulation on the polishing pad, leading to wafer defects and inefficient material removal rates, particularly for low-k materials.
Innovation Solution
A CMP composition comprising inorganic abrasive particles, chelating agents, corrosion inhibitors, non-ionic surfactants, pad-cleaning agents, and oxidizing agents, along with a specific pH range, to enhance material removal rates and maintain a clean polishing surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CMP processes are used for copper and ruthenium substrates, then polishing can be performed, but debris accumulates on the polishing pad leading to wafer defects and reduced manufacturing precision
Solution Approach 1:
The patent introduces a specifically formulated CMP composition as an intermediary substance between the polishing pad and the copper/ruthenium substrate. This composition contains chelating agents that bind to metal debris, preventing it from adhering to the polishing pad surface. The composition acts as a mediator that facilitates material removal while capturing debris in solution, thereby preventing pad contamination and wafer defects.
Solution Approach 2:
The patent modifies the chemical parameters of the CMP environment by controlling pH levels and introducing specific chelating agents. These parameter changes alter the chemical state of metal debris during polishing, transforming it from an adhesive solid that contaminates the pad into a complexed species that remains suspended in the slurry. This parameter modification prevents debris accumulation while maintaining effective material removal.
2Productivity
If high material removal rates are achieved for copper and ruthenium, then polishing efficiency improves, but pad contamination increases
Solution Approach 1:
The patent converts the harmful effect of high-speed material removal (which generates excessive debris) into a beneficial process. By introducing chelating agents in the CMP composition, the metal debris that would normally contaminate the pad is instead captured in stable complexes within the slurry. The high material removal rate becomes advantageous because the chelating agents efficiently manage the increased debris load, transforming what would be contamination into a controlled chemical process.
Solution Approach 2:
The CMP composition serves as an intermediary system that decouples material removal rate from pad contamination. The chelating agents in the composition act as mediators that intercept metal particles at the moment of generation, preventing their deposition on the pad regardless of the polishing speed. This intermediary mechanism allows high productivity without the usual penalty of pad contamination.
3Productivity
If copper is polished effectively, then material removal is efficient, but copper contamination and diffusion into dielectric layers occurs
Solution Approach 1:
The chelating agents in the CMP composition act as intermediary substances that bind to copper ions immediately during the polishing process. This chemical mediation prevents copper atoms from migrating into the dielectric layers by forming stable complexes that remain in the slurry phase. The copper is effectively removed from the substrate while being simultaneously captured by the chelating agents, preventing both contamination and diffusion.
Solution Approach 2:
The patent alters the chemical parameters of the polishing environment by adjusting pH and introducing chelating agents. These parameter changes shift the copper from a mobile, contamination-prone state to a stable, complexed state. The modified chemical parameters enable efficient copper removal while the chelating environment prevents copper diffusion into sensitive dielectric structures.
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 high material removal rates for copper and ruthenium layers while minimizing pad contamination, ensuring a clean polishing surface and maintaining the integrity of low-k materials.
Implementation Method 1
CMP utilizes the interplay of chemical and mechanical action to achieve the planarity of the to-be-polished surfaces. Chemical action is provided by a chemical composition, also referred to as CMP composition or CMP slurry.
Implementation Method 2
Mechanical action is usually carried out by a polishing pad which is typically pressed onto the to-be-polished surface and mounted on a moving platen.
Implementation Method 3
A CMP composition comprising inorganic abrasive particles, chelating agents, corrosion inhibitors, non-ionic surfactants, pad-cleaning agents, and oxidizing agents
Implementation Method 4
A CMP composition comprising inorganic abrasive particles, chelating agents, corrosion inhibitors, non-ionic surfactants, pad-cleaning agents, and oxidizing agents
Data Source
AI summary
The presently claimed invention relates to a chemical-mechanical polishing (CMP) composition and chemical-mechanical polishing (CMP) methods. The presently claimed invention particularly relates to a composition and process for chemical-mechanical polishing of substrates containing copper and ruthenium, specifically, semiconductor substrates containing copper and ruthenium.