Mini LED Array Substrate Copper Layering to Reduce Warping
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Solution Overview
Problem
The manufacturing of Mini LED substrates faces challenges due to the high stress caused by thick copper drive lead layers, which can lead to substrate warping and damage, while also requiring high current load capabilities.
Innovation Solution
A layered structure is implemented, including a base substrate, a metal wiring layer with a thin first copper layer, a planarization layer, and a drive lead layer with a thicker second copper layer, which is electrically connected to the metal wiring layer, allowing for reduced substrate stress and enhanced current handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a thick copper drive lead layer is used to meet high current load requirements, then the current handling capability is improved, but the substrate stress increases causing warping and manufacturing defects
Solution Approach 1:
The copper layer is segmented into two distinct layers: a first copper layer (220) with smaller thickness formed directly on the base substrate, and a second copper layer (401) with larger thickness formed on the planarization layer. This segmentation allows the current handling function to be distributed, with the thicker second layer providing high current capacity while the thinner first layer minimizes substrate stress
Solution Approach 2:
The solution transitions from a single-layer copper structure to a multi-layer vertical structure by adding the planarization layer (320) between the first and second copper layers. This dimensional change allows the thicker second copper layer to be positioned away from the substrate, reducing its direct stress impact while maintaining its current handling capability through vertical stacking
2Reliability
If a thick copper drive lead layer is formed directly on the substrate, then the electrical connection is improved, but the manufacturing process becomes difficult due to substrate warping
Solution Approach 1:
The planarization layer (320) is formed in advance before depositing the second copper layer (401). This preliminary action creates a flat, stable surface that supports the formation of the thick second copper layer without causing substrate warping, thereby enabling reliable electrical connection while maintaining manufacturing process stability
Solution Approach 2:
The planarization layer (320) acts as an intermediary between the first copper layer (220) and the second copper layer (401). It mediates the stress relationship by providing a buffer that allows the thick second copper layer to be formed without directly transmitting excessive stress to the substrate, thus enabling reliable electrical connection while maintaining manufacturing stability
Data Source
AI summary
The present disclosure provides an array substrate and a manufacturing method thereof, a display panel and a backlight module. The manufacturing method of the array substrate includes: providing a base substrate; forming a metal wiring layer on a side of the base substrate, the metal wiring layer including a first copper metal layer; forming a planarization layer on a side of the metal wiring layer away from the base substrate; forming a drive lead layer on a side of the planarization layer away from the base substrate, the drive lead layer being electrically connected to the metal wiring layer, the drive lead layer including a second copper metal layer with a thickness larger than that of the first copper metal layer; forming a functional device layer on a side of the drive lead layer away from the base substrate.