Laser Etching Semiconductor Layer Using Fluorinated Polymer Mediator
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Solution Overview
Problem
Laser etching methods struggle to separate a material layer deposited on two different materials without damaging either, as the required fluence for separation often deteriorates or separates the metal electrodes, making it impossible to simultaneously remove the semiconductor layer from a plastic substrate and metal electrodes using a single irradiation process.
Innovation Solution
A method involving the deposition of a third material with greater chemical affinity to the first material than to the second materials, allowing for laser beam application on the third material's surface to separate the first material layer with reduced energy, using a fluorinated polymer like CYTOP to absorb the laser and increase bonding enthalpy with the semiconductor material, thereby reducing the necessary fluence for separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a high fluence laser beam is applied to separate the semiconductor layer from the plastic substrate, then the separation efficiency is improved, but the metal electrodes are deteriorated or separated from the substrate
Solution Approach 1:
A third material layer is introduced as an intermediary between the semiconductor layer and the substrate. This intermediary layer has specific optical properties that allow it to absorb laser energy and facilitate separation at lower fluence levels, thereby protecting the metal electrodes from damage while maintaining effective separation of the semiconductor layer.
Solution Approach 2:
The invention changes the optical parameters of the system by introducing a material with specific absorption characteristics at the laser wavelength. This parameter change enables the use of lower laser fluence (below 55 mJ/cm²) to achieve separation, transforming the process from one that damages electrodes to one that protects them while maintaining separation efficiency.
2Ease of operation
If a single laser irradiation is applied to the entire semiconductor layer, then the process simplicity is improved, but it is impossible to separate the semiconductor layer from both plastic substrate and metal electrodes simultaneously
Solution Approach 1:
The third material layer serves multiple functions simultaneously: it acts as a bonding layer between the semiconductor and substrate, provides laser energy absorption, and enables universal separation from both plastic and metal substrates using a single irradiation process. This multi-functionality resolves the contradiction between process simplicity and separation completeness.
3Manufacturing precision
If chemical processing is used to remove the semiconductor layer, then the separation capability is improved, but residues are left on the substrate
Solution Approach 1:
The invention replaces chemical processing with a physical laser-based separation mechanism. The third material layer absorbs laser energy and facilitates mechanical separation through blister formation and interface delamination, eliminating the need for chemical agents that would leave residues. This substitution achieves both complete separation and substrate cleanliness.
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 decreases the minimum laser energy required for separation, preventing damage to metal electrodes and allowing for the removal of the semiconductor layer from both plastic and metal substrates without residues, with fluence reduced from 70 mJ/cm2 to 50 mJ/cm2 for a 100-nanometer semiconductor layer, extending the usable fluence range and minimizing material degradation.
Implementation Method 1
By irradiating the layer of material to be removed, the electromagnetic energy heats up the surface thereof, after which the heat propagates all the way to the interface between the two materials where it is stored until a blister forms
Implementation Method 2
the heat propagates all the way to the interface between the two materials where it is stored until a blister forms
Implementation Method 3
using a fluorinated polymer like CYTOP to absorb the laser and increase bonding enthalpy with the semiconductor material, thereby reducing the necessary fluence for separation
Data Source
AI summary
A method for etching with a laser beam having a predetermined wavelength an area of a layer of a first material, said area being deposited at the surface of at least two second materials, includes: depositing a layer of a third material on the layer of the first material, the first and the third materials having a chemical affinity on application of the laser beam greater than the chemical affinity during said application between the first material and each of said at least two second materials; and applying the laser beam to an area of a free surface of the layer of third material vertically above the area of the layer of first material with a fluence of said laser beam causing the separation of said area.