Laser Local Metallization for Precise Solar Cell Contacts
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Solution Overview
Problem
Current solar cell manufacturing techniques are inefficient and costly, particularly in achieving high electrical conversion efficiency and precise metallization, often requiring multiple processes and materials like silver, which is expensive and has high electrical resistance.
Innovation Solution
The Laser Assisted Metallization Patterning (LAMP) technique uses a laser to deposit and pattern metal directly onto solar cell substrates, allowing for localized metal deposition and patterning in a single operation, potentially replacing silver with aluminum and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional metallization techniques are used, then manufacturing process is established, but manufacturing cost is high and electrical conversion efficiency is limited
Solution Approach 1:
The patent extracts and removes silver from the metallization process, replacing it with aluminum. This eliminates the need for expensive silver materials while maintaining functional performance, directly reducing manufacturing cost without compromising electrical conversion efficiency
Solution Approach 2:
The patent changes the metallization parameters by using aluminum instead of silver, and employs laser-based processing parameters (pulse duration, power density, wavelength) to achieve precise metal deposition. These parameter changes enable cost-effective metallization with improved electrical performance
2Manufacturing precision
If multiple metallization processes are used, then metal deposition is achieved, but device complexity and manufacturing steps increase
Solution Approach 1:
The patent merges multiple metallization steps (metal deposition, patterning, and bonding) into a single laser processing operation. The laser simultaneously deposits aluminum metal, patterns it into desired configurations, and bonds it to the substrate, eliminating the need for separate process steps and reducing overall device complexity
Solution Approach 2:
The laser processing system performs multiple functions: it acts as a heat source for metal deposition, a patterning tool for creating conductive patterns, and a bonding mechanism for attaching metal to the substrate. This multi-functionality simplifies the manufacturing process while maintaining high precision metallization
3Reliability
If silver is used for metallization, then electrical conductivity is achieved, but material cost increases and electrical resistance remains high
Solution Approach 1:
The patent replaces expensive silver with inexpensive aluminum, using a cost-effective material that achieves the required electrical conductivity. The aluminum serves as a disposable metallization layer that provides sufficient electrical performance without the high material cost of silver
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
LAMP achieves higher efficiency and lower manufacturing costs by enabling precise, cost-effective metallization with smaller feature sizes and tighter pitches, improving solar cell performance while simplifying the manufacturing process.
Implementation Method 1
A metal foil is located over a substrate and exposed to a laser beam, thereby heating and melting portions of the metal foil
Implementation Method 2
heating and melting portions of the metal foil
Implementation Method 3
The laser beam is used to deposit and pattern metal directly onto solar cell substrates
Data Source
AI summary
Local metallization of semiconductor substrates using a laser beam, and the resulting structures, e.g., micro-electronic devices, semiconductor substrates and/or solar cells, are described. For example, a solar cell includes a substrate and a plurality of semiconductor regions disposed in or above the substrate. A plurality of conductive contact structures is electrically connected to the plurality of semiconductor regions. Each conductive contact structure includes a locally deposited metal portion disposed in contact with a corresponding a semiconductor region.