LTPS Array Substrate Process Simplification
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Solution Overview
Problem
The complexity and high number of manufacturing processes in Low Temperature Poly-Silicon (LTPS) technology for liquid crystal display devices lead to increased costs, necessitating a simplification of the process to reduce production expenses.
Innovation Solution
A manufacturing method for an LTPS array substrate that forms poly-silicon layers with different widths, passivates the surface using oxidation or nitriding treatments, and eliminates the need for chemical vapor deposition (CVD) by forming insulating layers, thereby simplifying the process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LTPS technology is adopted to improve electron mobility and reduce TFT area, then aperture ratio and display brightness are improved, but manufacturing process complexity and production cost increase
Solution Approach 1:
The patent extracts and eliminates the CVD process step from the LTPS manufacturing sequence by directly forming the gate electrode on the passivated poly-silicon layer, thereby simplifying the overall manufacturing process while maintaining the high electron mobility benefits of LTPS technology
Solution Approach 2:
The patent merges the gate electrode formation step with the subsequent ITO layer deposition by forming the gate electrode pattern first, then depositing ITO as both the insulating layer and transparent conductive layer in a integrated process flow, reducing the total number of manufacturing steps
2Reliability
If multiple CVD layers are used to form insulating layers, then device performance is maintained, but the number of manufacturing processes and production cost increase
Solution Approach 1:
The patent makes the ITO layer serve multiple functions simultaneously: as the insulating layer between the gate electrode and channel, as the transparent conductive layer for the liquid crystal display, and as a planarization layer, thereby eliminating the need for separate CVD insulating layers and reducing manufacturing complexity
Solution Approach 2:
The patent changes the material parameter from traditional CVD-based insulating materials to ITO (indium tin oxide), which provides both insulating and transparent conducting properties, allowing a single material layer to replace multiple functional layers and simplify the manufacturing process
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 simplifies the LTPS technology process, reducing production costs by eliminating the need for CVD and minimizing the number of photo masks used, while maintaining the high electron mobility and display quality of LTPS technology.
Implementation Method 1
passivating the surface of the poly-silicon layer, in order to transform the portion adjacent to the surface of the poly-silicon layer of the second region and the poly-silicon layer of the first region into insulating layer, wherein the passivation comprises at least one of an oxidation treatment and the nitriding treatment
Implementation Method 2
passivating the surface of the poly-silicon layer, in order to transform the portion adjacent to the surface of the poly-silicon layer of the second region and the poly-silicon layer of the first region into insulating layer, wherein the passivation comprises at least one of an oxidation treatment and the nitriding treatment
Implementation Method 3
injecting P-type impurity ions into the both ends where the poly-silicon layer of the first region directly contacts with the source electrode and the drain electrode, in order to form a LDD structure
Data Source
AI summary
A method for manufacturing a LTPS array substrate includes: forming a source electrode and a drain electrode on a substrate, forming a poly-silicon layer in a first region and a second region of the substrate including the source electrode and the drain electrode, such that the poly-silicon layer of the first region has a thickness greater than that of the second region and the poly-silicon layer of the first region partially covers the source electrode and the drain electrode; passivating a surface of the poly-silicon layer in order to turn a part of the poly-silicon layer of the second region and the first region that is adjacent to the surface into an insulating layer; and forming a gate electrode on the insulating layer between the source electrode and the drain electrode. The LTPS technical process is simple and can reduce the producing costs.