CMP Polishing Composition for Ruthenium Removal and Copper Protection
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Solution Overview
Problem
Current CMP slurries struggle to effectively remove ruthenium and hard mask materials in semiconductor substrates without causing copper corrosion or defects, especially in advanced multicomponent integration schemes where ruthenium is used as a liner material.
Innovation Solution
A polishing composition comprising an abrasive, pH adjuster, barrier film removal rate enhancer, low-k removal rate inhibitor, azole-containing corrosion inhibitor, and ruthenium removal rate enhancer, along with optional chelating and oxidizing agents, is used to minimize copper corrosion and achieve selective removal of ruthenium and hard mask materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CMP slurries are used to remove ruthenium and hard mask materials, then polishing effectiveness is reduced, but copper corrosion and defects are caused
Solution Approach 1:
The patent modifies the chemical composition parameters of the CMP slurry by incorporating specific additives including chelating agents (e.g., EDTA, DTPA), oxidizing agents (e.g., H2O2, O3), and complexing agents (e.g., ammonia, amines). These parameter changes enable selective removal of ruthenium and hard mask materials while suppressing copper corrosion through controlled chemical reactions
Solution Approach 2:
The patent introduces intermediary substances that mediate between the abrasive and the substrate materials. Chelating agents form complexes with copper ions to prevent corrosion, while oxidizing agents facilitate selective oxidation of ruthenium and hard mask materials. These intermediaries enable differential removal rates without direct harmful interaction with copper
2Productivity
If ruthenium removal rate is increased, then polishing efficiency improves, but selectivity and copper protection are compromised
Solution Approach 1:
The patent creates locally differentiated chemical environments through multiple additives that act selectively on different materials. Chelating agents locally protect copper regions while oxidizing agents and abrasive components locally attack ruthenium and hard mask regions. This local quality differentiation enables high ruthenium removal rates while maintaining copper corrosion resistance
Solution Approach 2:
The CMP slurry functions as a composite chemical system combining multiple active ingredients (chelating agents, oxidizing agents, complexing agents, and abrasives) that work synergistically. The composite formulation provides both aggressive ruthenium removal capability and protective copper corrosion resistance through the combined effects of its components
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 effectively polishes ruthenium and hard mask materials while minimizing copper corrosion, maintaining favorable removal rates and selectivity, suitable for advanced semiconductor fabrication processes.
Implementation Method 1
a polishing composition that includes an abrasive
Implementation Method 2
an azole-containing corrosion inhibitor
Implementation Method 3
optional chelating and oxidizing agents
Data Source
AI summary
A polishing composition, includes an abrasive; a pH adjuster; a barrier film removal rate enhancer; a low-k removal rate inhibitor; an azole-containing corrosion inhibitor; and a ruthenium removal rate enhancer. A method of polishing a substrate includes the steps of: applying the polishing composition described herein to a surface of a substrate, wherein the surface comprises ruthenium or a hard mask material; and bringing a pad into contact with the surface of the substrate and moving the pad in relation to the substrate.