Metallised Semiconductor Substrate Coating with Cascade Rinsing
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Solution Overview
Problem
The production of metallized semiconductor substrates, particularly the front side of solar cells, faces challenges with thin conductor structures that offer high ohmic resistance and adhesion issues, while existing processes generate significant metal waste and require complex and costly disposal of environmentally harmful electrolytes.
Innovation Solution
A multi-stage method involving immersion in a coating bath, light-induced coating, and a rinsing device with a metal-containing rinsing medium that recycles and replaces discharged electrolyte, reducing waste and enabling the reuse of valuable metals, with a system comprising a coating bath, rinsing device, and evaporation unit for concentration of the rinsing medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If thin conductor structures are used on the light incident side to maximize surface area for photon capture, then the surface area available for capturing photons is improved, but the ohmic resistance increases and adhesion problems occur
Solution Approach 1:
The conductor structure is segmented into a grid pattern with main lines and cross lines, creating multiple parallel conduction paths. This segmentation allows the structure to maintain high surface area coverage while providing multiple routes for current flow, thereby reducing overall ohmic resistance and improving reliability without requiring thick continuous metal layers.
2Ease of manufacture
If conventional metallization processes are used, then conductor structures can be applied to semiconductor substrates, but significant metal waste is generated and complex disposal of environmentally harmful electrolytes is required
Solution Approach 1:
The patent implements a closed-loop system where the electrolyte is continuously filtered to recover metal ions, and spent electrolyte is regenerated through ion exchange resins. This allows the electrolyte to be reused multiple times, significantly reducing metal waste disposal requirements while maintaining ease of manufacture for conductor structure application.
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 method significantly reduces metal waste disposal costs, recycles valuable metals, and maintains high electrical conductivity and mechanical connection, while minimizing ohmic resistance and adhesion problems, operating more economically than conventional processes.
Implementation Method 1
coating, in particular light-induced or light-assisted coating, the surface of the immersed substrate
Implementation Method 2
evaporation unit for concentration of the rinsing medium
Implementation Method 3
coating bath containing an electrolyte
Data Source
AI summary
The invention relates to a method for producing metallised semiconductor substrates, in which a substrate is immersed in a coating bath, where it is coated in a preferably light-induced or light-assisted manner. The coated substrate is then transferred to a rinsing device for removing metal residue from the electrolyte. In the rinsing device, the substrate is subjected to a cascade rinsing process. Metal-containing rinsing medium that accrues during the rinsing process is at least partially fed back into the coating bath. The invention further relates to an installation for carrying out such a method.