Micro LED Array Package Planarization for Display Alignment
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Solution Overview
Problem
The challenge lies in manufacturing LED array packages where small LED chips at the micrometer level, due to height deviations from the scribing process, result in tilting and step issues during mounting, leading to chromatic aberration and increased costs, especially when integrated into display panels with limited design flexibility and high process complexity.
Innovation Solution
The solution involves a semiconductor planarizing process that forms a uniform height for LED chips by grinding and polishing the solder balls and molding member, ensuring all light emitting surfaces are on the same horizontal plane, using a circuit board with a metal pattern layer and insulating layer for electrical connection, and employing a molding member to surround the LED chips and solder balls for protection and alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If small LED chips are mounted directly onto a package body, then individual driving capability is achieved, but tilting and step issues occur due to height deviation from scribing process
Solution Approach 1:
A planarization layer is introduced as an intermediary between the LED chips and the package body. This layer compensates for height deviations caused by the scribing process, ensuring that all LED chips are positioned at the same height on the package body, thereby eliminating tilting and step issues while maintaining individual driving capability
Solution Approach 2:
The thickness of the planarization layer is adjusted to match the height deviation of the LED chips. By changing the parameter of layer thickness, the surface uniformity is achieved, resolving the alignment precision problem without affecting the electrical connection and individual driving function
2Manufacturing precision
If precise bonding process is performed between LED chips and package body, then mounting accuracy is improved, but process complexity and cost increase
Solution Approach 1:
The planarization layer is formed in advance before mounting the LED chips. This preliminary action pre-compensates for height deviations, allowing subsequent mounting processes to be simpler and more accurate without requiring complex precision bonding procedures
Solution Approach 2:
The height deviation problem is extracted and addressed separately through the planarization layer, decoupling the mounting precision requirement from the bonding process complexity. This allows standard bonding processes to achieve high mounting accuracy
3Adaptability or versatility
If existing PCB substrate is used for mounting LED chips, then design flexibility is maintained, but minimum pitch gap limits array density and increases layer count
Solution Approach 1:
The package body is designed with a smaller minimum pitch gap compared to traditional PCB substrates. This parameter change in the substrate geometry allows LED chips to be mounted closer together, increasing array density while maintaining design flexibility through the same mounting interface
Data Source
AI summary
The present invention relates to a micro Light Emitting Diode (LED) matrix array package, including: a plurality of light emitting devices including a base substrate and a semiconductor laminated layer formed on the base substrate; a plurality of solder balls formed on the semiconductor laminated layer of the plurality of light emitting devices, respectively; a molding member configured to surround the light emitting devices and the solder balls; and a circuit board formed on the molding member, in which upper surfaces of the solder balls are exposed from the molding member, the circuit board includes a contact layer consisted of a metal pattern layer electrically connected with the plurality of solder balls exposed from the molding member and an insulating layer adjacently disposed to the metal pattern layer, and a thickness from the base substrate of each of the plurality of light emitting devices to an upper surface of each of the exposed solder balls is the same each other.