Solar Cell Manufacturing via Integrated Wet Etching

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Solution Overview

Problem

Conventional solar cell manufacturing processes face challenges with increased substrate damage and higher installation and maintenance costs due to the need for additional wet etching apparatuses, particularly in achieving high conversion efficiency beyond 15%.

Innovation Solution

A method that integrates saw damage removal, reactive ion etching, doping, damage removal etching, and edge isolation using a single wet etching apparatus, with specific solutions like KOH or NH4OH/H2O/H2O2 for damage removal and HCl/HF for cleaning, and HNO3/H2SO2/H2O2 for edge isolation, to minimize substrate movement and reduce equipment requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a wet etching process is added to remove plasma damage and perform edge isolation, then the conversion efficiency is improved, but the substrate damage rate increases

Engineering Contradiction:
Improveconversion efficiencyVSAvoidsubstrate damage rate
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent combines multiple functions (damage removal etching and edge isolation) into a single wet etching process step, eliminating the need for separate process steps and reducing substrate handling operations that cause damage

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The wet etching process is designed to perform multiple functions simultaneously: removing plasma damage from the surface and creating edge isolation in one operation, reducing the number of separate apparatuses and process steps required

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If an additional wet etching apparatus is introduced, then the damage removal etching process can be performed, but the installation and maintenance costs increase

Engineering Contradiction:
Improvedamage removal effectivenessVSAvoidnumber of etching apparatuses
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The existing wet etching apparatus is designed to perform multiple functions including damage removal etching, edge isolation, and cleaning, eliminating the need for additional specialized equipment

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

Multiple etching functions are merged into a single wet etching apparatus, reducing equipment complexity and associated installation and maintenance costs

Inventive Principle:
Principle #5Merging (Combining)

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 reduces substrate damage and installation/maintenance costs while maintaining or improving conversion efficiency by optimizing the etching processes within a single apparatus, enhancing the solar cell's performance.

Implementation Method 1

removing a damage from a surface of the substrate using an SDR (saw damage removal) process

Methodology Applied
Scientific EffectChemical etching:

Implementation Method 2

texturing the surface of the substrate using an RIE (reactive ion etching) process

Methodology Applied
Scientific EffectReactive ion etching:

Implementation Method 3

cleaning the surface of the substrate using a solution containing HCL/HF

Methodology Applied
Scientific EffectChemical cleaning:

Implementation Method 4

etching an edge of the substrate to isolate the edge from an anti-reflective film

Methodology Applied
Scientific EffectChemical etching:

Data Source

PatentEP2691989B1Method for manufacturing solar cell
Publication Date: 2023.05.03 HANWHA CHEMICAL CORPORATION
  • EP2691989B1 patent drawingFigure 1~2
  • EP2691989B1 patent drawingFigure 3~4
  • EP2691989B1 patent drawingFigure 5

AI summary

Provided is a method of manufacturing a solar cell, wherein a solar cell is manufactured by combining a damage removal etching process, a texturing process and an edge isolation process. The method is advantageous in that RIE and DRE are conducted, and then DRE/PSG and/or an edge isolation removal process are simultaneously conducted, so that the movement of a substrate (that is, a wafer) is minimized, thereby reducing the damage rate of the substrate.