Copper Cleaning Formulation for Microelectronics
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Solution Overview
Problem
Conventional cleaning chemistries for microelectronic devices often fail to effectively remove residues and contaminants, such as post-CMP, post-etch, and post-ash residues, which can lead to damage, poor adhesion, and electrical performance issues in copper metallization and dielectric materials.
Innovation Solution
A cleaning composition comprising a solvent, a corrosion inhibitor selected from ribosylpurines, adenosine derivatives, and purine-saccharide complexes, along with a quaternary base and an amine, is used to contact the microelectronic device, effectively removing residues and contaminants without damaging low-k dielectric materials or corroding metal interconnects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cleaning chemistries are used to remove residues, then cleaning action is provided, but copper metallization is damaged and dielectric materials are corroded
Solution Approach 1:
The patent changes the chemical parameters of the cleaning composition by using a non-oxidizing formulation with specific pH range (7-11) and incorporating copper corrosion inhibitors (0.01-5 wt%) along with surfactants and chelating agents. This parameter modification allows effective residue removal while preventing copper damage and dielectric corrosion that occur with conventional oxidizing cleaners.
Solution Approach 2:
The patent introduces copper corrosion inhibitors as intermediary substances that mediate between the cleaning action and copper metallization. These inhibitors (such as benzotriazole, hydroxylamine, and their derivatives) form protective complexes with copper ions, preventing direct corrosive interaction while allowing the cleaning composition to remove residues effectively.
2Productivity
If strong cleaning chemistries are used to remove post-CMP and post-etch residues, then residue removal efficiency is improved, but adhesion of subsequent layers deteriorates
Solution Approach 1:
The patent modifies the chemical parameters by using a non-oxidizing cleaning system with controlled pH (7-11) and specific additive combinations (surfactants, chelating agents, corrosion inhibitors). This parameter set provides sufficient residue removal capability while maintaining surface chemistry that promotes good adhesion of subsequent dielectric and metal layers, unlike strong oxidizers that create poor adhesion surfaces.
Solution Approach 2:
The cleaning composition is designed to provide different local actions: surfactants for residue emulsification, chelating agents for metal ion complexation, and corrosion inhibitors for copper protection. This localized functional differentiation allows effective residue removal from specific areas while preserving the underlying metal and dielectric surfaces for optimal adhesion.
3Productivity
If conventional oxidizing cleaners are used to clean residues, then residue removal is achieved, but low-k dielectric materials are damaged
Solution Approach 1:
The patent fundamentally changes the oxidation state parameter by using a non-oxidizing cleaning system. The composition maintains a controlled pH (7-11) without strong oxidizing agents, thereby preventing the oxidation and damage of low-k dielectric materials while still achieving effective residue removal through surfactant and chelating agent mechanisms.
Solution Approach 2:
The patent converts the potential harm of strong cleaning action into benefit by using non-oxidizing chemistry. Instead of relying on oxidation to remove residues (which damages low-k dielectrics), the composition uses surfactant-based emulsification and chelating agent complexation to remove residues gently, turning a potentially harmful oxidizing process into a beneficial non-destructive cleaning action.
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 achieves substantial removal of residues and contaminants, with at least 85% efficiency, thereby ensuring the integrity and performance of microelectronic devices by preventing damage to copper metallization and maintaining the integrity of dielectric materials.
Implementation Method 1
the corrosion inhibitor comprises a species selected from the group consisting of ribosylpurines and methylated or deoxy derivatives thereof; degradation products of adenosine and adenosine derivatives; purine-saccharide complexes
Implementation Method 2
A cleaning composition comprising a solvent, a corrosion inhibitor selected from ribosylpurines, adenosine derivatives, and purine-saccharide complexes, along with a quaternary base and an amine, is used to contact the microelectronic device, effectively removing residues and contaminants
Data Source
AI summary
A cleaning composition and process for cleaning post-chemical mechanical polishing (CMP) residue and contaminants from a microelectronic device having said residue and contaminants thereon. The cleaning compositions include novel corrosion inhibitors. The composition achieves highly efficacious cleaning of the post-CMP residue and contaminant material from the surface of the microelectronic device without compromising the low-k dielectric material or the copper interconnect material.