Cleaning Composition for Semiconductor Memory Etch Residue Removal
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Solution Overview
Problem
The existing methods for fabricating semiconductor memory devices face challenges in effectively removing etch residues on the sidewalls of variable resistance elements without damaging the layers, particularly the tunnel barrier layer, which is crucial for maintaining the integrity and performance of the memory device.
Innovation Solution
A cleaning composition comprising water, a fluorine-containing compound, and an amine, with a pH between 7 and 14, is used to selectively remove etch residues without damaging the patterns, ensuring the preservation of the tunnel barrier layer and other critical layers in the semiconductor memory device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing cleaning methods are used to remove etch residues, then etch residues can be removed, but the tunnel barrier layer and other critical layers are damaged
Solution Approach 1:
The patent changes the chemical parameters of the cleaning solution by specifying a pH range of 7-14 and using specific fluorine-containing compounds (such as NH4F, HF, CF3COOH) combined with amines (such as TMAH, TEA). This parameter optimization enables effective etch residue removal while preventing damage to the tunnel barrier layer, resolving the contradiction between cleaning effectiveness and layer integrity.
Solution Approach 2:
The patent employs a composite cleaning solution containing multiple components: fluorine-containing compounds, amines, and water in specific ratios. This composite formulation provides synergistic effects where the fluorine-containing compounds dissolve metal fluorides and the amines control pH and prevent unwanted reactions, achieving both thorough etch residue removal and protection of sensitive layers.
2Productivity
If strong cleaning agents are used to remove etch residues, then cleaning effectiveness is improved, but damage to patterns and layers increases
Solution Approach 1:
The patent optimizes the pH parameter to a controlled range of 7-14, avoiding excessively strong acidic or basic conditions that would damage patterns. The specific combination of fluorine-containing compounds and amines creates a cleaning solution with sufficient cleaning power while maintaining pH within safe limits for the device layers.
Solution Approach 2:
The fluorine-containing compounds act as intermediaries that selectively react with etch residues (metal fluorides) without attacking the organic and inorganic layers. The amines serve as mediators that control the chemical environment, ensuring the cleaning action is directed at residues rather than the device structure.
3Loss of time
If conventional cleaning processes are used, then processing time is reduced, but etch residues remain on sidewalls
Solution Approach 1:
The patent modifies the chemical composition parameters by introducing fluorine-containing compounds that rapidly dissolve metal fluoride etch residues. This parameter change enables complete residue removal in a single cleaning step without requiring extended processing times or multiple sequential cleaning operations.
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
This approach effectively removes etch residues while preventing damage to the memory device layers, thereby maintaining the pattern profile and improving the magnetization characteristics and data storage capabilities of the semiconductor memory.
Implementation Method 1
a fluorine-containing compound or an amine... to remove a metal polymer or a metal oxide deposited on sidewalls
Implementation Method 2
The amine may include hydroxylamine, alkylamine, alkanolamine, or an aromatic amine... The cleaning composition may have a pH in a range of 9 to 11
Data Source
AI summary
A method for fabricating an electronic device including a semiconductor memory may include: forming a material layer over a substrate; forming a material pattern by etching the material layer, the etching providing an etch residue on sidewalls of the material pattern; and removing the etch residue, wherein removing of the etch residue includes performing a cleaning process using a cleaning composition including water and a fluorine-containing compound or an amine, and having a pH in a range of 7 to 14.