Micro LED Back Surface Grinding for Residual Removal
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Solution Overview
Problem
The manufacturing process of optoelectronic semiconductor devices, particularly Micro LEDs, faces challenges in removing residuals on the wafer back without using chemicals, as conventional acid-based methods are ineffective due to material constraints, leading to reduced illumination efficiency and increased complexity in selecting suitable temporary substrates.
Innovation Solution
A method involving the formation of a protective layer over micro-sized optoelectronic semiconductor elements, followed by grinding to expose a new surface, which removes residuals and defects like the buffer and non-doped layers, thereby enhancing illumination efficiency without chemical cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If chemical cleaning (hydrochloric acid) is used to remove gallium metal residuals, then illumination efficiency is improved, but the temporary substrate material selection becomes more difficult due to chemical resistance requirements
Solution Approach 1:
The patent extracts and removes the gallium metal residuals from the back surface of the optoelectronic semiconductor elements through mechanical grinding, eliminating the need for chemical cleaning processes. This extraction approach resolves the contradiction by achieving residual removal (improving illumination efficiency) without requiring the temporary substrate to withstand chemical exposure (expanding material selection flexibility).
Solution Approach 2:
The patent replaces the chemical cleaning system with a mechanical grinding system. Instead of using hydrochloric acid to remove gallium metal residuals, a grinding apparatus mechanically removes the residuals along with a portion of the buffer layer. This substitution resolves the contradiction by achieving the same cleaning objective without chemical resistance requirements.
2Illumination intensity
If a protective layer is formed and grinding is performed to remove residuals, then illumination efficiency increases, but the manufacturing process complexity increases
Solution Approach 1:
The patent merges the residual removal function with the buffer layer removal function into a single grinding operation. By forming a protective layer over the optoelectronic semiconductor elements and grinding through the buffer layer, both the gallium metal residuals and the buffer layer are removed simultaneously. This merging approach resolves the contradiction by achieving multiple objectives (residual removal and buffer layer removal) in one step, thereby improving illumination efficiency without proportionally increasing process complexity.
Solution Approach 2:
The patent performs preliminary action by forming the protective layer before the grinding process. This protective layer prevents damage to the optoelectronic semiconductor elements during grinding while enabling effective removal of the buffer layer and residuals. The preliminary formation of this protective structure resolves the contradiction by facilitating a more effective single-step grinding process that improves illumination efficiency without requiring multiple separate processing steps.
3Illumination intensity
If the buffer layer is removed by grinding, then illumination efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by forming a protective layer specifically over the optoelectronic semiconductor elements while leaving the buffer layer exposed in other areas. During grinding, the protective layer protects the elements that require preservation, while the buffer layer is removed from areas where it is not needed. This local differentiation resolves the contradiction by enabling selective removal and preservation, improving illumination efficiency while managing precision requirements through localized protection.
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 increases illumination efficiency by eliminating residual and defect-related light absorption, allowing for higher resolution and improved performance in devices like display panels and lighting systems, without the need for chemical processing.
Implementation Method 1
grinding the protective layer until a residual on a back surface of each of the micro-sized optoelectronic semiconductor elements and the back surface are removed to expose a new surface
Data Source
AI summary
A manufacturing method of an optoelectronic semiconductor device includes: providing a matrix substrate, which comprises a substrate and a matrix circuit disposed on the substrate; transferring a plurality of micro-sized optoelectronic semiconductor elements from a temporary substrate to the matrix substrate, wherein the micro-sized optoelectronic semiconductor elements are separately disposed on the matrix substrate, and at least one electrode of each micro-sized optoelectronic semiconductor element is electrically connected with the matrix circuit; forming a protective layer completely covering the micro-sized optoelectronic semiconductor elements, wherein the height of the protective layer is greater than the height of the micro-sized optoelectronic semiconductor elements; and grinding the protective layer until a residual on a back surface of each micro-sized optoelectronic semiconductor element and the back surface are removed to expose a new surface.