Semiconductor Texturing with Non-Volatile Alkoxylated Glycols
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Solution Overview
Problem
Existing semiconductor texturing methods face challenges with non-uniformity, reproducibility, and high evaporation rates of volatile components, leading to increased light reflectance and manufacturing costs, particularly in the use of isopropanol-based solutions which require frequent replacement and result in suboptimal reflectance performance.
Innovation Solution
An aqueous texturing solution comprising non-volatile, high molecular weight alkoxylated glycols and their ether and ether acetate derivatives with a flash point of 75°C or greater, combined with alkaline compounds, is applied to semiconductor substrates to create uniform and reproducible pyramid structures, reducing light reflectance and improving conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If isopropanol-based texturing solutions are used, then texturing can be performed immediately without pre-treatment, but the solution evaporates rapidly due to low flash point (82°C boiling point), requiring frequent replacement and increasing manufacturing costs
Solution Approach 1:
The patent changes the key parameter of the texturing solution from volatile isopropanol (boiling point 82°C) to non-volatile alkoxylated glycols (boiling point >150°C). This parameter change maintains the immediate usability of the solution while dramatically reducing evaporation losses, eliminating the need for frequent solution replacement and reducing manufacturing costs.
2Productivity
If conventional texturing solutions are used, then texturing process can be performed, but the texturing is non-uniform and reflectance is high (14%-27%), failing to achieve optimal performance
Solution Approach 1:
The patent uses a composite texturing solution containing alkoxylated glycols (such as polyethylene glycol or polypropylene glycol) combined with alkaline agents like potassium hydroxide or sodium hydroxide. This composite formulation achieves uniform texturing with repeatable pyramid structures and reduces light reflectance to optimal levels, improving both process execution and manufacturing precision.
3Productivity
If texturing solutions with volatile components are used, then the texturing process can proceed, but reproducibility of pyramidal structures is poor and defective products increase
Solution Approach 1:
The patent extracts the volatile component (isopropanol) from the texturing solution and replaces it with non-volatile alkoxylated glycols. This extraction of the problematic volatile element eliminates the reproducibility issues caused by evaporation during the texturing process, ensuring consistent pyramid structure formation and reducing defective products.
4Speed
If high concentration of alkaline agents is used to improve texturing rate, then texturing speed increases, but surface uniformity deteriorates and reflectance increases
Solution Approach 1:
The patent employs a composite solution where alkoxylated glycols work synergistically with alkaline agents. The alkoxylated glycols moderate the action of the alkaline agents, allowing faster texturing rates while maintaining surface uniformity and achieving optimal reflectance reduction. The composite formulation balances speed and precision that cannot be achieved with alkaline agents alone.
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 achieves reduced light reflectance across a wide spectrum, enhancing the conversion of light into electric energy, while minimizing solution evaporation and downtime, thus lowering manufacturing costs and improving the efficiency of semiconductor devices.
Implementation Method 1
wet chemical pyramidal (tetragonal) structure texturing of (100)-orientated silicon surfaces use alkaline media
Implementation Method 2
greater oxidation of the glycol, results in smaller pyramids
Implementation Method 3
Solar cells are devices that convert light energy incident on their surfaces such as sunlight into electric energy
Data Source
AI summary
Semiconductors are textured with aqueous solutions containing non-volatile alkoxylated glycols, their ethers and ether acetate derivatives having molecular weights of 170 or greater and flash points of 75° C. or greater. The textured semiconductors can be used in the manufacture of photovoltaic devices.