GaN Micro Device Plasma Etching Without Chemical Photoresist Strippers
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Solution Overview
Problem
The environmental burden and economic challenges associated with conventional photoresist removal processes in micro LED manufacturing, which involve complex chemical substances difficult to recycle, hinder efficient and sustainable production.
Innovation Solution
A method involving a GaN-based epitaxial structure with a plasma etching process using a patterned photoresist layer to form mesas, allowing for the complete removal of the photoresist layer without a conventional stripper, thereby manufacturing micro devices like micro LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional photoresist strippers are used to remove the photoresist layer, then the photoresist layer can be removed, but complex chemical substances are produced causing environmental burden and difficult recycling
Solution Approach 1:
The patent extracts the photoresist removal function from the chemical stripper process and integrates it into the plasma etching process. The plasma etching simultaneously performs both photoresist removal and semiconductor layer etching, eliminating the need for separate chemical stripper treatment and avoiding harmful chemical waste.
Solution Approach 2:
The patent merges the photoresist removal step with the plasma etching step into a single integrated process. By combining these two functions, the process eliminates the need for conventional chemical strippers and their associated environmental problems while maintaining both removal and etching capabilities.
2Ease of manufacture
If conventional photoresist strippers are used, then photoresist removal is achieved, but the chemical substances are difficult to recycle and achieve reasonable economic benefits
Solution Approach 1:
The patent extracts the photoresist removal function from the chemical stripper process and integrates it into the plasma etching process. The plasma etching simultaneously performs both photoresist removal and semiconductor layer etching, eliminating the need for separate chemical stripper treatment and avoiding harmful chemical waste.
Solution Approach 2:
The patent changes the physical and chemical parameters of the etching process by using plasma instead of chemical solutions. This parameter change enables the photoresist to be removed through plasma etching at controlled rates, making the process environmentally friendly and economically viable through easier waste management.
3Object-affected harmful factors
If plasma etching is performed to remove photoresist, then environmental burden is reduced, but the photoresist layer must be completely removed during etching to avoid residue
Solution Approach 1:
The patent applies a specific photoresist composition formulation before etching that is optimized for complete plasma etchability. This preliminary action ensures that the photoresist layer can be completely removed during plasma etching without leaving residues, achieving both environmental benefits and manufacturing precision.
Solution Approach 2:
The patent changes the physical and chemical parameters of the etching process by using plasma instead of chemical solutions. This parameter change enables the photoresist to be removed through plasma etching at controlled rates, making the process environmentally friendly and economically viable through easier waste management.
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 enables efficient and sustainable micro device production by eliminating the need for hazardous chemical strippers, promoting environmental sustainability and economic viability.
Implementation Method 1
performing a plasma etching process to the GaN-based epitaxial structure through the patterned photoresist layer
Data Source
AI summary
A method of manufacturing micro devices includes: preparing a GaN-based epitaxial structure including a p-type GaN layer, a n-type GaN layer on the p-type GaN layer, and an undoped GaN layer on the n-type GaN layer; forming a photoresist layer on the GaN-based epitaxial structure with the undoped GaN layer contacting the photoresist layer; patterning the photoresist layer; performing a plasma etching process to the GaN-based epitaxial structure through the patterned photoresist layer until the patterned photoresist layer is completely removed, such that a plurality of mesas are formed on the etched GaN-based epitaxial structure, in which a height of the mesas is at least 1.0 μm; and continuing to perform the plasma etching process until the undoped GaN layer is completely removed and the etched GaN-based epitaxial structure is cut into a plurality of micro devices.