Micro LED Pixel Structure With Hard Mask Dicing Precision
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Solution Overview
Problem
Current micro light-emitting diode pixel structures face challenges in achieving small spacing, large light-emitting area, high process yield, and low cost due to fixed thickness and size limitations of light-emitting diodes, making it difficult to further reduce the size of pixel structures.
Innovation Solution
A micro light-emitting diode pixel structure is developed, incorporating micro light-emitting diode chips, redistribution layers, bonding pads, an insulating layer, and a flexible material layer, with a hard mask pattern used in an anisotropic etching process to improve precision and accuracy, reducing dicing loss and increasing yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional dicing methods are used on micro light-emitting diode pixel structures, then the manufacturing process can be completed, but the dicing precision is insufficient and sidewall flatness is poor leading to high dicing loss
Solution Approach 1:
The patent introduces a sacrificial layer as an intermediary substance between the micro light-emitting diode pixel structure and the dicing blade. This sacrificial layer acts as a mediator that facilitates precise dicing by providing a controlled release mechanism, thereby improving dicing precision and reducing sidewall damage that leads to material loss.
Solution Approach 2:
The patent extracts and removes the sacrificial layer after it has served its purpose during the dicing process. By taking out the sacrificial layer, the patent enables clean separation of diced structures with minimal damage to the sidewalls, thus reducing dicing loss while maintaining manufacturing precision.
2Length of moving object
If the size of pixel structures is reduced to achieve smaller spacing, then the light-emitting area can be optimized, but the fixed thickness and size of light-emitting diodes prevent further reduction
Solution Approach 1:
The patent transitions from conventional planar dicing to three-dimensional dicing by introducing a sacrificial layer that enables vertical separation. This dimensional change allows the pixel structures to be separated in the thickness direction rather than only in the planar direction, thereby reducing spacing without increasing structural complexity.
Solution Approach 2:
The patent embeds the sacrificial layer within the pixel structure stack, nesting it between functional layers. This nested configuration allows the sacrificial layer to serve its purpose during dicing while maintaining a compact overall structure, enabling size reduction without adding external complexity.
3Manufacturing precision
If anisotropic etching with hard mask pattern is used, then dicing precision and sidewall flatness are improved, but the process complexity increases
Solution Approach 1:
The patent applies anisotropic etching selectively to specific regions defined by the hard mask pattern, rather than uniformly across the entire structure. This localized approach improves sidewall flatness in critical areas while minimizing the impact on overall process complexity by limiting the sophisticated etching to where it is most needed.
Solution Approach 2:
The patent forms the hard mask pattern and sacrificial layer structure before performing the anisotropic etching. This preliminary preparation simplifies the subsequent etching process by pre-defining the etch boundaries and protecting areas that should not be etched, thereby improving sidewall flatness without proportionally increasing process complexity.
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
The solution enhances the precision and accuracy of the dicing process, improves the flatness of the sidewall profile, and increases the process yield of micro light-emitting diode pixel structures, allowing for smaller dimensions and reduced dicing loss.
Implementation Method 1
performing an anisotropic etching process to remove a portion of the flexible material layer at the periphery
Data Source
AI summary
A micro light-emitting diode pixel structure and a method for forming the same are provided. The micro light emitting diode pixel structure includes micro light emitting diode chips, redistribution layers, bonding pads, an insulating layer, a flexible material layer and a first hard mask pattern. The redistribution layers are electrically connected to electrode surfaces of the micro light-emitting diode chips. The bonding pads are disposed under the redistribution layers. The insulation layer is disposed between the redistribution layers and the bonding pads. The flexible material layer disposed on the insulating layer to cover the micro light-emitting diode chips, the redistribution layers and insulation layer. The first hard mask pattern is disposed under or above the flexible material layers. In a cross-sectional view, the first hard mask pattern has a first edge and the flexible material layer has a second edge flush with the first edge.