Post-Etch Cleaning Composition for Tungsten and Cobalt Compatibility
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Solution Overview
Problem
Current cleaning compositions fail to effectively remove titanium-containing, copper-containing, tungsten-containing, and cobalt-containing post-etch residues from microelectronic devices without damaging low-k dielectric materials or corroding metallic interconnects, as they often require ammonia or alkali hydroxide salts that are harmful to these materials.
Innovation Solution
An aqueous cleaning composition comprising non-ionic surfactant corrosion inhibitors, etchant sources, passivating agents, and optional organic solvents and oxidizing agents, which are specifically designed to remove post-plasma etch residues without damaging ultra low-k dielectric materials or metal interconnects, using a formulation that is substantially devoid of ammonia and alkali hydroxide salts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cleaning chemistries (ammonia or alkali hydroxide salts) are used to remove post-etch residues, then residue removal effectiveness is improved, but damage to low-k dielectric materials and corrosion of metallic interconnects occurs
Solution Approach 1:
The patent changes the chemical composition parameters of the cleaning solution by substituting conventional ammonia and alkali hydroxide salts with alternative cleaning agents that have different chemical properties. This allows effective residue removal while avoiding the harmful effects on low-k dielectric materials and metal interconnects.
Solution Approach 2:
The patent introduces intermediary substances (alternative cleaning agents) that mediate between the need for effective residue removal and the need to protect sensitive materials. These intermediaries perform the cleaning function without causing damage to the underlying structures.
2Reliability
If titanium-containing post-etch residues are removed using conventional wet cleaning chemistries, then some residue removal is achieved, but complete removal is not accomplished and damage to device materials occurs
Solution Approach 1:
The patent modifies the chemical parameters of the cleaning solution to achieve complete titanium residue removal. By adjusting the composition to exclude ammonia and alkali hydroxide salts and include alternative agents, the solution achieves both complete removal and material compatibility.
3Reliability
If cleaning compositions are designed to remove all types of post-etch residues (titanium, copper, tungsten, cobalt), then comprehensive cleaning performance is improved, but compatibility with ILD and metal interconnect materials becomes difficult to maintain
Solution Approach 1:
The patent creates a universal cleaning composition that performs multiple functions: removing titanium, copper, tungsten, and cobalt residues while simultaneously being compatible with low-k dielectric materials and metal interconnects. This multi-functional formulation resolves the contradiction between comprehensive cleaning and material compatibility.
Solution Approach 2:
The patent uses a composite cleaning formulation containing multiple alternative cleaning agents work together synergistically. This composite approach enables the solution to handle diverse residue types while maintaining compatibility with sensitive device materials.
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 removes at least 90% of titanium-containing, copper-containing, tungsten-containing, and cobalt-containing residues from microelectronic devices while protecting the underlying low-k dielectric and metal interconnect materials, ensuring compatibility with advanced microelectronic device structures.
Implementation Method 1
comprising non-ionic surfactant corrosion inhibitors
Implementation Method 2
comprising etchant sources
Implementation Method 3
comprising passivating agents
Data Source
AI summary
Cleaning compositions and processes for cleaning post-plasma etch residue from a microelectronic device having said residue thereon. The composition achieves highly efficacious cleaning of the residue material, including titanium-containing, copper-containing, tungsten-containing, and/or cobalt-containing post-etch residue from the microelectronic device while simultaneously not damaging the interlevel dielectric, metal interconnect material, and/or capping layers also present thereon.