Water-Rich Hydroxylamine Cleaning Formulation for Semiconductor Substrates
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Solution Overview
Problem
Current cleaning compositions for semiconductor substrates, particularly in back-end-of-the-line operations, face challenges in removing photoresist and plasma ash residues without using toxic materials like dimethyl acetamide and often require additional rinsing steps to avoid aluminum corrosion, while also needing to maintain the integrity of metal structures.
Innovation Solution
A water-rich hydroxylamine-based cleaning composition with a corrosion inhibitor and alkanolamines having a pKa<9, which effectively removes residues without corroding or dulling metal circuitry, eliminating the need for intermediate rinsing steps and minimizing silicon and aluminum etch rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional cleaning compositions containing dimethyl acetamide (DMAC) are used, then residue removal efficiency is improved, but toxicity and environmental harm increase
Solution Approach 1:
The patent changes the chemical composition parameters by replacing toxic DMAC with a water-rich formulation containing hydroxylamine and specific alkanolamines (pKa<9), achieving effective residue removal without the toxicity associated with conventional solvents
Solution Approach 2:
The patent uses readily available, non-toxic materials (water, hydroxylamine, alkanolamines) that can be easily disposed of, replacing expensive and hazardous specialized solvents like DMAC while maintaining cleaning effectiveness
2Object-affected harmful factors
If water-rich cleaning compositions are used, then toxicity is reduced, but aluminum corrosion increases
Solution Approach 1:
The patent introduces specific alkanolamines with pKa<9 as intermediary substances that mediate between water and aluminum, preventing direct corrosive interaction while maintaining the water-rich non-toxic formulation benefits
Solution Approach 2:
The patent carefully controls the pH and composition parameters of the water-rich formulation, using hydroxylamine and specific alkanolamines to achieve a pH range that prevents aluminum corrosion while maintaining effective cleaning capability
3Object-generated harmful factors
If additional rinsing steps are added, then aluminum corrosion is prevented, but process complexity and time increase
Solution Approach 1:
The patent combines multiple functions (cleaning, corrosion protection, residue removal) into a single cleaning composition formulation, eliminating the need for separate rinsing steps that would add process complexity
Solution Approach 2:
The water-rich cleaning composition performs multiple functions simultaneously: it removes residues effectively, protects aluminum from corrosion, and eliminates the need for additional rinsing steps, making it a universal solution for semiconductor substrate cleaning
4Productivity
If hydroxylamine-based compositions are used, then residue removal efficiency is improved, but silicon and aluminum etch rates increase
Solution Approach 1:
The patent optimizes the concentration and pH parameters of hydroxylamine-based formulations, using specific alkanolamines (pKa<9) to control the reactivity, achieving effective residue removal while maintaining etch rates below 5nm/min for both silicon and aluminum
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 provides efficient residue removal with reduced toxicity and environmental impact, ensuring compatibility with aluminum and silicon substrates while maintaining low etch rates and avoiding additional rinsing steps, thus ensuring the integrity of semiconductor substrates.
Implementation Method 1
A water-rich hydroxylamine-based cleaning composition with a corrosion inhibitor and alkanolamines having a pKa<9, which effectively removes residues
Implementation Method 2
A water-rich hydroxylamine-based cleaning composition with a corrosion inhibitor and alkanolamines having a pKa<9, which effectively removes residues without corroding or dulling metal circuitry
Data Source
AI summary
A water-rich hydroxylamine formulation for photoresist and post-etch/post-ash residue removal in applications wherein a semiconductor substrate comprises aluminum. The cleaning composition comprises from about 2 to about 15% by wt. of hydroxylamine; from about 50 to about 80% by wt. of water; from about 0.01 to about 5.0% by wt. of a corrosion inhibitor; from about 5 to about 45% by wt. of a component selected from the group consisting of: an alkanolamine having a pKa<9.0, a water-miscible solvent, and a mixture thereof. Employment of such composition exhibits efficient cleaning capability for Al substrates, minimal silicon etch while protecting aluminum for substrates comprising both materials.