Passivation Layer Positioning Mark for TFT LCD Array
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Solution Overview
Problem
Conventional TFT LCD array positioning marks made of metal are prone to deformation and shifting during high-temperature cell and module processes, leading to positioning failures due to the influence of silicon nitride film formation and stress.
Innovation Solution
Designing and manufacturing a passivation layer positioning mark on the TFT LCD array using a silicon nitride layer, specifically in a cruciform or hollow pattern, which is more stable and resistant to deformation, to align with metal positioning marks on the gate or source/drain layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a metal positioning mark is used in the TFT LCD array, then the positioning mark can be formed early in the manufacturing process, but the positioning mark deforms and shifts during high-temperature cell and module processes
Solution Approach 1:
The patent changes the material parameter of the positioning mark from metal to silicon nitride. Silicon nitride has different thermal properties compared to metal, making it resistant to deformation during high-temperature processes. This material substitution resolves the contradiction by maintaining positioning accuracy while still allowing early formation in the manufacturing process.
Solution Approach 2:
The positioning mark is formed as part of the silicon nitride layer structure, which may include multiple layers or composite construction. This composite approach provides both early formation capability and thermal stability during subsequent high-temperature processing stages.
2Ease of manufacture
If a metal positioning mark is used, then the positioning mark can be formed with the gate electrode layer, but the positioning mark is affected by silicon nitride film formation stress and high temperature
Solution Approach 1:
The patent changes the material composition parameter from metal to silicon nitride, which fundamentally alters the response to film formation stress and high temperature. Silicon nitride's material properties make it inherently resistant to deformation under these conditions, thereby maintaining reliability while preserving ease of manufacture through integration with existing silicon nitride layer formation processes.
3Manufacturing precision
If the positioning mark is made of silicon nitride layer, then the positioning mark is stable and resistant to deformation, but the positioning mark requires additional layer formation steps
Solution Approach 1:
The patent merges the positioning mark formation with the existing silicon nitride layer formation process. Instead of creating a separate positioning mark structure, the positioning mark is patterned and formed as an integrated part of the silicon nitride layer stack, utilizing the same deposition and etching processes already required for the device structure.
Solution Approach 2:
The silicon nitride layer serves multiple functions: it provides the device's passivation and structural layers, and simultaneously forms the positioning mark. This multi-functionality eliminates the need for separate positioning mark formation steps, resolving the contradiction between improved positioning accuracy and increased process complexity.
Data Source
AI summary
The present invention relates to TFT LCD array positioning mark designing and manufacturing methods. The TFT LCD array positioning mark manufacturing method includes: (1) forming a passivation layer of TFT LCD array; (2) providing a mask corresponding to the passivation layer, the mask comprising a passivation layer positioning mark that corresponds to a metal positioning mark of the TFT LCD array; and (3) using the mask to form a corresponding passivation layer positioning mark on the passivation layer. The TFT LCD array positioning mark designing method includes: forming a passivation layer positioning mark on a passivation layer of an TFT LCD array to correspond to a metal positioning mark of the TFT LCD array. The present invention provides TFT LCD array positioning mark designing and manufacturing method, wherein a passivation layer positioning mark that is designed and manufactured with them shows a pattern that is more stable and is not susceptible to deformation so as to eliminate the problem of positioning failure of the metal positioning mark occurring in the cell and module processes.