Dual Source-Drain Layer Display Substrate via Planarization Mask

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Solution Overview

Problem

Existing OLED display substrates face poor transistor performance, which affects the display effect, due to the complexity and inefficiency of current patterning processes that lead to performance deterioration and increased production costs.

Innovation Solution

A display substrate structure with a first and second source-drain structure layer, where the second active via is formed after the first drain-source electrode, avoiding high-temperature annealing and cleaning processes that could damage the second active layer, and using a cured planarization layer as a mask to form a complete second active via, ensuring the quality and uniformity of both transistors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional single source-drain structure layer is used, then the manufacturing process is simpler, but the transistor performance deteriorates due to process complexity and inefficiency

Engineering Contradiction:

Improvetransistor performanceVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The source-drain structure is divided into two separate layers: a first source-drain structure layer containing a first source electrode and first drain electrode, and a second source-drain structure layer containing a second source electrode and second drain electrode. This segmentation allows independent optimization of each layer's function and improves overall transistor performance by eliminating the performance deterioration caused by conventional single-layer structures.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If high-temperature annealing and cleaning processes are used to form the second active via, then the via can be completely formed, but the second active layer is damaged

Engineering Contradiction:

Improvesecond active via qualityVSAvoidsecond active layer damage

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

A cured planarization layer is introduced as an intermediary masking layer during the formation of the second active via. This planarization layer protects the second active layer from damage by high-temperature annealing and cleaning processes while still allowing the via to be completely formed. The planarization layer serves as a temporary protective barrier that can be removed after serving its protective function.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The planarization layer is formed and cured before the high-temperature annealing and cleaning processes are applied to create the second active via. This preliminary action establishes protective coverage over the second active layer before any harmful processes occur, preventing damage in advance rather than attempting to repair it afterward.

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If multiple patterning steps are used to form the second active via, then the via can be completely formed, but the production cost increases

Engineering Contradiction:

Improvesecond active via completenessVSAvoidproduction cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The formation of the second active via is merged with the formation of the planarization layer into a single integrated process step. The planarization layer is deposited and cured, then used directly as a mask for via formation, combining what would otherwise be separate patterning operations into one unified process, thereby reducing production costs while maintaining via completeness.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The planarization layer serves multiple functions: it provides surface planarization for subsequent processing, acts as a protective mask during high-temperature annealing and cleaning, and serves as a patterning mask for via formation. This multi-functionality eliminates the need for separate dedicated mask layers and reduces the total number of patterning steps required.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11678530B2Display substrate and preparation method thereof, and display apparatus

Publication Date: 2023.06.13 BOE TECHNOLOGY GROUP CO LTD

AI summary

Provided are a display substrate and a preparation method thereof, and a display apparatus. The display substrate includes a substrate, an active structure layer disposed on the substrate, a first source-drain structure layer disposed on a side of the active structure layer away from the substrate, and a second source-drain structure layer disposed on a side of the first source-drain structure layer away from the substrate. The active structure layer includes a first active layer and a second active layer. The first source-drain structure layer includes a first active via and a first source-drain electrode, and the first source-drain electrode is connected to the first active layer through the first active via; and the second source-drain structure layer includes a second active via and a second source-drain electrode, and the second source-drain electrode is connected to the second active layer through the second active via.