Silicon Wafer Cleaning Agent Prevents Pattern Collapse
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in semiconductor device production is pattern collapse during cleaning, particularly for micro-scale circuit patterns with high aspect ratios, due to capillary forces caused by differences in residual liquid height, which reduces yield and is not effectively addressed by existing methods.
Innovation Solution
A silicon wafer cleaning agent comprising a water-based cleaning liquid and a water-repellent cleaning liquid with a reactive moiety chemically bondable to Si and a hydrophobic group, or a nitrogen-containing solvent, to reduce capillary forces and prevent pattern collapse, allowing for efficient cleaning of finely uneven patterns without modifying conventional apparatuses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a gas-liquid interface passes through high aspect ratio patterns after cleaning, then the cleaning process is completed, but the pattern collapses due to capillary forces
Solution Approach 1:
The patent changes the physical-chemical parameters of the cleaning liquid by using dilute hydrofluoric acid instead of conventional ammonia-based cleaners, and controls the liquid's surface tension and contact angle properties to reduce capillary forces during the gas-liquid interface passage, preventing pattern collapse while maintaining cleaning effectiveness
Solution Approach 2:
The patent introduces a specifically formulated cleaning liquid as an intermediary substance that mediates between the cleaning requirement and the pattern stability requirement. The cleaning liquid contains dilute hydrofluoric acid with controlled surface properties that allow it to clean the wafer surface while simultaneously providing capillary force reduction to prevent pattern collapse during the drying phase
2Adaptability or versatility
If micro-scale circuit patterns are used to reduce device size, then device sophistication is improved, but production yield decreases due to pattern collapse
Solution Approach 1:
The patent modifies the chemical composition and physical parameters of the cleaning liquid to specifically address the needs of micro-scale patterns. By using dilute hydrofluoric acid with controlled concentration and surface tension properties, the method enables safe cleaning of high aspect ratio patterns that would otherwise collapse, thereby maintaining high production yield while supporting advanced micro-scale device fabrication
3Productivity
If conventional ammonia-based cleaning agents are used, then cleaning effectiveness is maintained, but wafer damage increases due to basicity
Solution Approach 1:
The patent inverts the conventional approach by switching from basic ammonia-based cleaners to acidic dilute hydrofluoric acid cleaners. This inversion resolves the contradiction by providing effective cleaning without the harmful basicity that damages wafer surfaces, particularly for sensitive micro-scale patterns
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 solution effectively reduces capillary forces, preventing pattern collapse and improving production yield, enabling the production of more sophisticated semiconductor devices with higher aspect ratios while maintaining cost-effectiveness and throughput.
Implementation Method 1
a water-repellent cleaning liquid for providing at least recessed portion of the uneven pattern with water repellency
Implementation Method 2
The magnitude of the capillary force is the absolute value of P obtained by the equation as represented below. It is expected from this equation that the capillary force can be reduced if decreasing γ or cos θ.
Implementation Method 3
a water-repellent cleaning liquid comprising a water-repellent compound having a reactive moiety chemically bondable to Si element in the silicon wafer and a hydrophobic group
Data Source
AI summary
A silicon wafer cleaning agent includes at least a water-based cleaning liquid, and a water-repellent cleaning liquid for providing water-repellent to an uneven pattern at least at recessed portions during a cleaning process. The water-repellent cleaning liquid is a liquid composed of a water-repellent compound containing a reactive moiety which is chemically bondable to Si in the silicon wafer, and a hydrophobic group, or is a liquid wherein 0.1 mass % or more of the water-repellent compound relative to the total quantity of 100 mass % of the water-repellent cleaning liquid and an organic solvent are mixed and contained therein. A cleaning process wherein a pattern collapse is easily induced can be improved by using the cleaning agent.