Array Substrate Via Structure for Gentle Slopes and Fewer Pinholes
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Solution Overview
Problem
Existing array substrate manufacturing methods face challenges in forming vias with smooth, gentle slopes to prevent pinholes and ensure reliable electrical connections, leading to potential circuit breaks and increased impedance.
Innovation Solution
A mask design with a fully light-transmitting area and a pattern area is used in lithographic patterning, where the pattern area includes partially light-transmitting and light-shielding slits to control light exposure and prevent pinholes, forming vias with a first structure having different light transmittance than the second structure, resulting in a sloped via that connects conductive members effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lithographic patterning is used to form vias, then the manufacturing process is simple, but the via slopes are steep and pinholes occur, leading to poor electrical connection reliability
Solution Approach 1:
The mask is divided into multiple functional regions: a first light-transmitting area for forming the via opening, a second light-transmitting area with different transmittance for controlling side wall etching, and a light-shielding area for defining the via footprint. This segmentation allows different parts of the mask to perform different functions in creating the desired via structure with gentle slopes.
Solution Approach 2:
Different regions of the mask are assigned different light transmittance properties. The first light-transmitting area has high transmittance to fully expose the via opening, while the second light-transmitting area has partial transmittance to provide controlled exposure for forming gentle side wall slopes. This local differentiation in optical properties enables precise control over the via morphology.
2Manufacturing precision
If conventional via formation methods are used, then the manufacturing process is fast, but the via slopes are steep causing pinholes and circuit breaks
Solution Approach 1:
The mask is pre-designed with specific geometric patterns and transmittance distributions before the lithographic process. The first light-transmitting area is pre-configured with dimensions and positions that will directly determine the via opening size and shape, while the second light-transmitting area is pre-arranged to control the side wall profile. This preliminary configuration eliminates the need for complex real-time adjustments during manufacturing.
Solution Approach 2:
The invention changes the optical parameters of the mask by introducing regions with different light transmittance values. By adjusting the transmittance of the second light-transmitting area relative to the first, the etching rate and via slope can be controlled. This parameter-based control provides a simple yet effective method to achieve precise via morphology without complicating the manufacturing process.
3Reliability
If simple mask designs are used, then the manufacturing process is easy, but pinholes form in the via structure
Solution Approach 1:
The second light-transmitting area acts as an intermediary region between the first light-transmitting area and the light-shielding area. This intermediate zone with partial light transmittance gradually transitions the exposure intensity, preventing abrupt changes that would cause pinholes. The intermediary region ensures uniform material removal and smooth via side walls, eliminating pinhole formation.
Solution Approach 2:
The mask design employs asymmetric light transmittance distribution, where the first light-transmitting area has higher transmittance than the second light-transmitting area. This asymmetric arrangement creates a controlled gradient in exposure intensity around the via opening, ensuring that the etching process proceeds uniformly from all directions and prevents pinhole formation that would occur with symmetric, uniform transmittance designs.
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 ensures the formation of vias with gentle slopes, reducing the risk of pinholes and improving the yield of connection members, thereby enhancing the reliability and efficiency of electrical connections in array substrates.
Implementation Method 1
the first structure has a light transmittance different from a light transmittance of the second structure
Data Source
AI summary
An array substrate includes a substrate and a via on a side of the substrate. The via includes a first structure and a second structure surrounding the first structure, and the first structure has a light transmittance different from the second structure. An orthographic projection of the first structure on the substrate has a substantially rectangular shape with a plurality of straight sides. An orthographic projection of the second structure on the substrate has a substantially octagonal shape, the second structure includes a plurality of first sub-structures and a plurality of second sub-structures, an orthographic projection of each first sub-structure on the substrate has a strip shape, the first sub-structures are parallel to the straight sides of the first structure in one-to-one correspondence, and an orthographic projection of each second sub-structure on the substrate has a tile shape. Each second sub-structure is between, and connects, two adjacent first sub-structures.