Aqueous Cleaner for Post-Etch Residue Removal
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Solution Overview
Problem
Conventional cleaning chemistries fail to effectively remove titanium-containing, copper-containing, and tungsten-containing post-plasma etch residues from microelectronic devices without damaging underlying dielectric materials or corroding metal interconnects, and no single composition has successfully addressed this issue while being compatible with low-k dielectric materials and metal interconnects.
Innovation Solution
An aqueous cleaning composition comprising corrosion inhibitors, water, etchant sources, chelating agents, passivating agents, and complexing agents, which are specifically formulated to remove post-plasma etch residues without damaging low-k dielectric materials or corroding metal interconnects, such as copper, tungsten, and cobalt, and can be used in various etching schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cleaning chemistries (ammonia or strong bases) are used to remove post-plasma etch residues, then residue removal effectiveness is improved, but damage to low-k dielectric materials and corrosion of metal interconnects occurs
Solution Approach 1:
The invention changes the chemical parameters of the cleaning composition by using a weak base (pH 7-11) instead of strong bases or ammonia, and incorporates specific additives (corrosion inhibitors, chelating agents, passivating agents) to modify the chemical environment. This allows effective residue removal while protecting sensitive materials.
Solution Approach 2:
The cleaning composition is a composite formulation containing multiple components: weak base, corrosion inhibitors, chelating agents, and passivating agents. Each component contributes to different aspects of the cleaning process, creating a synergistic effect that removes residues while protecting underlying structures.
2Reliability
If ammonia-containing chemistries are used to remove titanium-containing residues, then cleaning performance is improved, but absorption into ILD pores increases dielectric constant
Solution Approach 1:
The invention extracts and removes ammonia and strong bases from the cleaning composition, replacing them with a weak base formulation. This eliminates the harmful absorption effect into ILD pores while maintaining residue removal capability through alternative chemical mechanisms.
Solution Approach 2:
The weak base acts as an intermediary chemical that provides residue removal functionality without the harmful effects of ammonia. The chelating agents serve as intermediaries to bind metal residues, and passivating agents protect the ILD surface, preventing direct harmful interactions.
3Reliability
If hydroxylamine-containing and ammonia-peroxide chemistries are used for cleaning, then residue removal is improved, but copper interconnect corrosion occurs
Solution Approach 1:
The invention applies preliminary protective action by incorporating corrosion inhibitors and passivating agents into the cleaning composition before the cleaning process occurs. These additives pre-establish protective layers on copper surfaces, preventing oxidation and corrosion during residue removal.
Solution Approach 2:
The invention changes the oxidation potential parameters by eliminating hydroxylamine and ammonia-peroxide combinations that cause copper corrosion. The weak base formulation with controlled pH and specific additives provides residue removal through alternative mechanisms that do not involve aggressive oxidation of copper.
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 post-plasma etch residues, including titanium, copper, and tungsten-containing residues, from microelectronic devices without compromising the integrity of low-k dielectric materials or metal interconnects, ensuring high cleaning performance and compatibility with advanced microelectronic device materials.
Implementation Method 1
The aqueous cleaning composition comprises corrosion inhibitors, etchants, chelating agents, and passivating agents
Implementation Method 2
The composition effectively removes at least 90% of post-plasma etch residues without damaging the underlying materials
Implementation Method 3
The aqueous cleaning composition comprises corrosion inhibitors
Implementation Method 4
The aqueous cleaning composition comprises corrosion inhibitors, etchants, chelating agents, and 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.