Copper Polishing Agent Composition for High-Speed CMP
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Solution Overview
Problem
Conventional copper polishing agents for CMP processes exhibit low polishing speed and reduced productivity, particularly when dealing with thick copper alloy films required for high-performance circuit boards and TSVs, necessitating a more efficient polishing solution.
Innovation Solution
A polishing agent comprising inorganic acid, amino acid, a protective film-forming agent, an abrasive, an oxidizing agent, and water, with specific ratios and additives such as organic acids and their acid anhydrides, to achieve high polishing speeds exceeding 30000 Å/min, ensuring smooth and rapid polishing of copper films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional polishing agents are used for thick copper alloy films, then polishing can be performed, but polishing speed is low and productivity is reduced
Solution Approach 1:
The patent changes the chemical composition parameters of the polishing agent by incorporating specific concentrations of oxidizing agents (0.1-10 wt%), organic acids (0.01-5 wt%), and their acid anhydrides (0.01-5 wt%). This chemical parameter optimization enables significantly higher polishing speeds exceeding 30000 Å/min for thick copper films, directly resolving the contradiction between maintaining polishability and improving productivity
Solution Approach 2:
The invention creates a composite polishing agent system combining multiple components: oxidizing agents (such as hydrogen peroxide, ammonium persulfate), organic acids (such as oxalic acid, maleic acid), acid anhydrides, and abrasive particles. This composite formulation synergistically enhances polishing performance on thick copper alloy films, achieving both high productivity and reduced polishing time
2Productivity
If higher polishing speed is achieved, then productivity improves, but surface smoothness may be compromised
Solution Approach 1:
The patent optimizes chemical composition parameters including oxidizing agent concentration (0.1-10 wt%), organic acid content (0.01-5 wt%), and acid anhydride content (0.01-5 wt%) to achieve a balanced polishing mechanism. This parameter control enables high polishing speeds while maintaining surface smoothness through controlled oxidation and removal rates
Solution Approach 2:
The organic acids and acid anhydrides act as intermediary substances that mediate between the oxidizing agent and the copper surface. They control the oxidation process to form removable copper oxide layers at optimal rates, ensuring both high polishing speed and smooth surface finish by preventing excessive or uneven oxidation
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 polishing agent significantly enhances polishing speed and productivity, enabling efficient processing of thick copper films up to 10 μm or greater, while maintaining surface smoothness and stability across varying film thicknesses.
Implementation Method 1
The basic mechanism of CMP employing a polishing agent comprising an oxidizing agent is considered to be that the metal film is polished by, first, oxidizing the metal film surface with the oxidizing agent to form an oxidation layer, and shaving of the oxidation layer with the abrasive
Implementation Method 2
shaving of the oxidation layer with the abrasive
Implementation Method 3
removing the metal film on the elevated sections by mechanical friction between the polishing agent and the metal film on the elevated sections
Data Source
AI summary
A polishing agent for copper polishing, comprising (A) an inorganic acid with divalent or greater valence, (B) an amino acid, (C) a protective film-forming agent, (D) an abrasive, (E) an oxidizing agent and (F) water, wherein the content of the component (A) is at least 0.08 mol/kg, the content of the component (B) is at least 0.20 mol/kg, the content of the component (C) is at least 0.02 mol/kg, and either or both of the following conditions (i) and (ii) are satisfied. (i): The proportion of the content of the component (A) with respect to the content of the component (C) is 2.00 or greater. (ii): It further comprises (G) at least one kind selected from among organic acids and their acid anhydrides.