Display Panel Substrate Structure for Uniform Thick Copper Plating
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Solution Overview
Problem
The electroplating method for fabricating thick copper films in LED display devices results in uneven thickness due to uneven electric field distribution, leading to conductivity issues and increased roughness, which are unsuitable for mass production.
Innovation Solution
A substrate design with a base substrate, organic layer, and metal layers, including a first metal layer as a seed layer and a second metal layer formed by electroplating, where the second metal layer's thickness is uniform due to controlled electric field distribution, enhanced adhesion, and selective etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If electroplating method is used to fabricate thick copper film, then copper thickness can be increased, but electric field distribution becomes uneven causing non-uniform thickness
Solution Approach 1:
The copper film fabrication is divided into two separate processes: first forming a thin seed layer by sputtering, then building up the thick copper film by electroplating. This segmentation allows each process to optimize for its specific thickness range, achieving both thickness and uniformity
Solution Approach 2:
A thin seed layer is formed by sputtering before electroplating to create a uniform base layer. This preliminary action ensures that the subsequent electroplating process deposits copper uniformly across the substrate, solving the non-uniform thickness problem while still achieving thick film requirements
2Quantity of substance
If electroplating method is used to fabricate thick copper film, then copper thickness can be increased, but etching time increases resulting in larger etching bias
Solution Approach 1:
The copper film formation is segmented into sputtering for the seed layer and electroplating for the thick layer, which together reduce the required etching time compared to forming the entire thick layer by electroplating alone
Solution Approach 2:
The patent changes the deposition parameters by using two different deposition methods (sputtering and electroplating) with different deposition rates and film properties, resulting in a composite structure that requires less etching time while maintaining the required thickness
3Quantity of substance
If semi-additive process is used to form thick copper layer patterns, then thick copper can be achieved, but thickness becomes uneven due to uneven electric field density
Solution Approach 1:
The patent segments the copper layer formation into two distinct stages: a thin uniform seed layer formed by sputtering, and a thick layer formed by electroplating. This segmentation allows the final copper layer to achieve both the required thickness and uniformity, overcoming the limitations of using semi-additive process for the entire thickness
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
Ensures uniform copper thickness, improving conductivity and preventing roughness, thus enhancing the substrate's performance and suitability for large-size LED displays.
Implementation Method 1
it is difficult to fabricate a copper film of such thickness by sputtering deposition method
Implementation Method 2
The electroplating method can fabricate a thick copper film
Data Source
AI summary
A substrate includes: a base substrate; an organic layer on the base substrate with openings defined through the organic layer; a first metal layer including first metal patterns, where the first metal pattern is in the opening, and includes a first portion parallel to a bottom of the opening and a second portion parallel to a lateral wall of the opening; a second metal layer having a thickness greater than a thickness of the first metal layer; where the second metal layer includes second metal patterns, the second metal pattern is located in the opening and is in contact with the first metal layer; and, a distance from a surface of the first metal layer away from the base substrate to a plane where the base substrate is located is smaller than a distance from a surface of the organic layer away from the base substrate to the plane.