Aqueous Oxidizing Cleaner for Post-Etch Residue Removal
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Solution Overview
Problem
Conventional cleaning chemistries fail to effectively remove titanium-containing post-plasma etch residues and hardmask materials from microelectronic devices without damaging underlying interlevel dielectric (ILD) materials or corroding metallic interconnects, such as copper, tungsten, and cobalt, due to their non-selectivity and compatibility issues.
Innovation Solution
An aqueous oxidizing cleaning composition comprising an oxidizing agent, an amine species as a stabilizer, and optional metal-chelating agents, organic co-solvents, and buffering species is used to selectively remove titanium-containing residues, polymeric sidewall residues, and copper-containing residues from microelectronic devices, maintaining compatibility with ILD and metal interconnects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cleaning chemistries are used to remove titanium-containing residues, then cleaning effectiveness is improved, but damage to ILD and corrosion of metal interconnects occurs
Solution Approach 1:
The patent changes the chemical parameters of the cleaning composition by using a peroxide-free oxidizing system with specific pH ranges (adjusted using buffers like ammonium fluoride, hydrofluoric acid, or ammonia) and controlled oxidizing agent concentrations. This parameter optimization enables effective titanium residue removal while preventing damage to ILD and corrosion of metal interconnects.
Solution Approach 2:
The cleaning composition is formulated as a composite system containing multiple components: oxidizing agents (such as ammonium persulfate, potassium permanganate, or sodium chlorite), chelating agents (like EDTA or DTPA), buffers, and surfactants. This composite formulation achieves synergistic effects that provide both effective titanium removal and protection of sensitive device structures.
2Manufacturing precision
If strong oxidizing agents are used to remove titanium-containing hardmask material, then removal effectiveness is improved, but bath-life is reduced
Solution Approach 1:
The patent optimizes the concentration and type of oxidizing agents to achieve effective titanium removal while controlling decomposition rates. By selecting specific oxidizing agents and adjusting their concentrations within defined ranges, the formulation maintains both high removal effectiveness and extended bath-life for cost-effective processing.
3Manufacturing precision
If ammonia-peroxide chemistry is used to remove residues, then cleaning performance is improved, but copper interconnect corrosion occurs
Solution Approach 1:
The patent extracts and eliminates ammonia and peroxide from the cleaning composition, replacing them with alternative oxidizing agents that do not cause copper corrosion. This removal of harmful components while maintaining cleaning functionality through alternative chemistry prevents copper interconnect damage.
Solution Approach 2:
The patent employs chelating agents that form stable complexes with copper ions, preventing corrosion while allowing the use of effective oxidizing agents. The chelating agents act as protective intermediaries that enable copper-safe cleaning performance.
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 achieves high selectivity and effectiveness in removing residues and hardmask materials while extending bath-life, ensuring minimal damage to ILD and metal interconnects, with enhanced storage stability and usage properties.
Implementation Method 1
An aqueous oxidizing cleaning composition comprising an oxidizing agent, an amine species as a stabilizer
Data Source
AI summary
An oxidizing aqueous cleaning composition and process for cleaning post-plasma etch residue and/or hardmask material from a microelectronic device having said residue thereon. The oxidizing aqueous cleaning composition includes at least one oxidizing agent, at least one oxidizing agent stabilizer comprising an amine species selected from the group consisting of primary amines, secondary amines, tertiary amines and amine-N-oxides, optionally at least one co-solvent, optionally at least one metal-chelating agent, optionally at least one buffering species, and water. The composition achieves highly efficacious cleaning of the residue material from the microelectronic device while simultaneously not damaging the interlevel dielectric and metal interconnect material also present thereon.