Dual Gate TFT Substrate Mask Reduction
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Solution Overview
Problem
The traditional single gate oxide semiconductor TFTs face stability issues such as environment stability, stress bias stability, and mask stability, leading to complex manufacturing processes and higher production costs due to the need for multiple masks and longer process flows.
Innovation Solution
A dual gate TFT substrate manufacturing method that simplifies the process by using one mask to form the source, drain, and top gate simultaneously, reducing the number of masks and process steps, while promoting stability through sequential deposition and patterning of layers with specific materials like molybdenum, titanium, aluminum, and copper for the metal layers, and Silicon Oxide or Nitride for isolation layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dual gate structure TFT substrate is used to improve stability, then TFT stability is improved, but the number of masks and process steps increases
Solution Approach 1:
The patent combines the formation of source, drain, and top gate into a single patterning step using one mask. The metal layer is patterned to simultaneously create all three components, merging what would traditionally require multiple separate fabrication steps into one operation, thereby reducing process complexity while maintaining the dual gate structure for improved TFT stability
Solution Approach 2:
The single mask serves multiple functions by defining the patterns for source, drain, and top gate simultaneously. This multi-functional approach allows one masking step to accomplish what would traditionally require multiple specialized masks, reducing the overall number of components needed in the fabrication process
2Manufacturing precision
If multiple masks are used to manufacture bottom gate, source/drain, and top gate separately, then manufacturing precision is improved, but production cost increases
Solution Approach 1:
The patent merges the patterning operations for source, drain, and top gate into a single step. By using one mask to define all three components simultaneously, the process reduces the number of alignment and patterning operations required, thereby lowering production costs while maintaining adequate manufacturing precision for the device structures
3Reliability
If a longer process flow is used to manufacture dual gate TFT, then TFT stability is improved, but productivity decreases
Solution Approach 1:
The patent combines multiple fabrication operations into a single patterning step. By forming source, drain, and top gate simultaneously in one mask operation, the process reduces the total number of sequential steps required, thereby improving manufacturing efficiency and productivity while still achieving the TFT stability benefits of the dual gate structure
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 method enhances TFT stability, reduces production costs, and simplifies the manufacturing process by integrating the bottom gate and top gate construction, resulting in a more efficient and cost-effective dual gate TFT substrate with improved structural simplicity.
Implementation Method 1
depositing a first metal layer on the substrate
Implementation Method 2
depositing a semiconductor layer on the first isolation layer
Implementation Method 3
depositing a second metal layer on the second isolation layer
Data Source
AI summary
Disclosed are a manufacturing method of a dual gate TFT substrate and a structure thereof. The manufacturing method of a dual gate TFT substrate includes sequentially manufacturing a bottom gate, a first isolation layer, an island shaped semiconductor layer, and a second isolation layer on a substrate; then, depositing a second metal layer, and implementing a patterning process to the second metal layer with one mask to form a source, a drain and a top gate at the same time; and then, sequentially manufacturing a third isolation layer and a pixel electrode. It can promote the stability of the TFT, reduce the amount of the masks, and shorten the process flow, simplifying the manufacture process and diminishing the production cost. In the structure of the dual gate TFT substrate, the structure is simple, and the stability of the TFT is better, and easy to manufacture.