TFT Array Substrate Via Contact Layout for Reliable Source Overlap
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Solution Overview
Problem
The use of multiple photo masks in TFT array substrate manufacturing leads to a lengthy process flow, increased difficulty, and higher costs, while overlapping issues between the semiconductor layer and the source electrode result in poor contact reliability.
Innovation Solution
The array substrate design includes a first auxiliary electrode connected to the source contact part within a via hole, ensuring its projection covers the source contact part completely, enhancing the overlapping reliability between the semiconductor layer and the source electrode without increasing the semiconductor layer thickness or via hole size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the source electrode is disposed below the semiconductor layer to reduce the number of photo masks, then the manufacturing process flow is shortened and costs are reduced, but the overlapping contact reliability between the semiconductor layer and source electrode deteriorates
Solution Approach 1:
A first auxiliary electrode is introduced as an intermediary component between the source electrode and source contact part. This auxiliary electrode fills the via hole and provides additional contact area, ensuring reliable electrical connection while maintaining the bottom-gate structure that reduces photo mask requirements
Solution Approach 2:
The auxiliary electrode extends the contact interface from a simple planar overlap to a three-dimensional structure that includes vertical filling of the via hole. This dimensional transition increases the effective contact area and improves reliability without adding lateral complexity
2Reliability
If the semiconductor layer thickness or via hole size is increased to improve overlapping reliability, then the contact reliability improves, but the device structure becomes more complex and manufacturing difficulty increases
Solution Approach 1:
The auxiliary electrode is formed in the same via hole that already exists for connecting the source electrode, utilizing the existing structural feature rather than requiring separate modifications. This self-service approach improves reliability without adding independent structural elements
Data Source
AI summary
An array substrate and a display panel are provided. The array substrate includes a substrate and a first conductive layer, a first insulating layer, a semiconductor layer, and a third conductive layer. The first conductive layer includes a source electrode and a light shielding electrode arranged at intervals. The semiconductor layer includes a channel part and a source contact part. A part of the source contact part is disposed inside the first via hole and connected to the source electrode. The third conductive layer includes a first auxiliary electrode corresponding to the source contact part. The first auxiliary electrode is connected to at least the source contact part located inside the first via hole. An orthographic projection of the source contact part located inside the first via hole on the substrate is within a range of an orthographic projection of the first auxiliary electrode on the substrate.