Post-CMP Cleaning Composition for Cobalt Substrates
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Solution Overview
Problem
Current post-CMP cleaning compositions are inadequate for efficiently removing residues and contaminants from cobalt or cobalt alloy substrates without damaging the materials, and they often exhibit foaming issues and environmental concerns.
Innovation Solution
A post-CMP cleaning composition comprising water-soluble nonionic copolymers, poly(acrylic acid) or acrylic acid-maleic acid copolymers, and corrosion inhibitors, with a pH range of 7.0 to 10.5, specifically designed to effectively remove residues and contaminants from cobalt or cobalt alloy substrates while minimizing foaming and environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional post-CMP cleaning compositions are used to remove residues from cobalt substrates, then cleaning effectiveness is improved, but the cobalt layer is damaged or etched
Solution Approach 1:
The invention changes the chemical parameters of the cleaning composition by using a weak base (ammonium hydroxide or potassium hydroxide) with controlled concentration (0.1-10%) and adjusting pH to 7-12, which enables effective cleaning of cobalt residues without causing excessive etching or damage to the cobalt layer
Solution Approach 2:
The invention uses a composite cleaning composition containing multiple components working together: weak base (for pH control and gentle cleaning), chelating agent (for binding metal ions), surfactant (for removing organic residues), and oxidizing agent (for breaking down contaminants), creating a synergistic effect that cleans effectively while protecting the cobalt layer
2Reliability
If strong cleaning agents are used to remove all contaminants, then cleaning effectiveness is improved, but foaming increases and environmental harm worsens
Solution Approach 1:
The invention changes the chemical parameters by using a weak base instead of strong bases, controlling the pH to 7-12 range, and limiting surfactant concentration to 0.1-5%, which reduces foaming and environmental harm while maintaining cleaning effectiveness through the synergistic action of multiple cleaning components
Solution Approach 2:
The invention converts potentially harmful strong cleaning agents into a gentler formulation using weak bases and controlled surfactant levels, while the combination of multiple milder agents (chelating agents, surfactants, oxidizing agents) working together achieves the same cleaning effect with reduced foaming and environmental impact
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 efficiently removes post-CMP residues and contaminants from cobalt or cobalt alloy substrates without affecting the electrical materials, reduces foaming, and is environmentally benign, making it suitable for various semiconductor and microelectronic device fabrication processes.
Implementation Method 1
The CMP slurries contain abrasive materials and various chemical additives as appropriate to the specific CMP process and requirements. At the end of the CMP process, contaminants and residues comprising particles from the CMP slurries, added chemicals, and reaction by-products remain on the polished substrate surface.
Implementation Method 2
a post chemical-mechanical-polishing (post-CMP) cleaning composition... comprising (A) one or more water-soluble nonionic copolymers, (B) poly(acrylic acid) (PAA) or acrylic acid-maleic acid copolymer, (C) water... capable of removing the post-CMP residue and contaminants
Implementation Method 3
the pH of the composition is in the range of from 7.0 to 10.5
Data Source
AI summary
Described is a post chemical-mechanical-polishing (post-CMP) cleaning composition comprising or consisting of: (A) one or more water-soluble nonionic copolymers of the general formula (I) and mixtures thereof, formula (I) wherein R1 and R3 are independently from each other hydrogen, methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-Butyl, or sec-butyl, R2 is methyl and x and y are an integer, 1 (B)poly(acrylic acid) (PAA) or acrylic acid-maleic acid copolymer with a mass average molar mass (Mw) of up to 10,000 g/mol, and (C) water, wherein the pH of the composition is in the range of from 7.0 to 10.5.