OLED Display MIM Capacitor Doping Masking
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Solution Overview
Problem
The manufacturing process of organic light emitting diode (OLED) displays is complicated due to the need for separate doping masking processes for forming capacitor electrodes, increasing production costs and complexity.
Innovation Solution
A method that simplifies the process by using a single doping masking step to form both the transistor and capacitor doping regions, with a specific metal layer configuration and doping opening design that allows for efficient impurity ion doping, enabling the formation of a Metal-Insulator-Metal (MIM) capacitor configuration with improved efficiency compared to Metal-Oxide-Semiconductor (MOS) configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate doping masking processes are used for forming capacitor electrodes, then the capacitor can be formed with proper doping, but the manufacturing process becomes complicated and production cost increases
Solution Approach 1:
The patent merges the doping masking processes for the transistor and capacitor into a single unified process. The doping mask is designed with first and second doping regions that correspond to the transistor doping region and capacitor doping region respectively, allowing both components to be doped simultaneously in one step rather than requiring separate masking processes.
Solution Approach 2:
The doping mask serves multiple functions simultaneously: it defines both the transistor doping region and the capacitor doping region, acts as a single masking layer for both components, and enables unified impurity ion implantation for both the transistor and capacitor electrodes, thereby reducing the total number of process steps.
2Manufacturing precision
If separate doping masking processes are used for forming capacitor electrodes, then proper doping control is achieved, but production cost increases
Solution Approach 1:
The patent combines multiple doping masking operations into a single unified doping mask structure, reducing the number of photolithography and etching steps required. This merger maintains precise doping control for both transistor and capacitor regions while significantly reducing production costs by eliminating redundant process steps.
Solution Approach 2:
The doping mask is designed in advance with pre-defined first and second doping regions that precisely correspond to the required transistor and capacitor doping areas. This preliminary design of the mask structure ensures that accurate doping control is achieved from the first doping step, eliminating the need for subsequent corrective or additional doping operations.
3Reliability
If MOS capacitor configuration is used, then the capacitor can be formed with semiconductor layer, but the capacitor efficiency is lower compared to MIM configuration
Solution Approach 1:
The patent transitions the capacitor configuration from MOS (Metal-Oxide-Semiconductor) to MIM (Metal-Insulator-Metal) by changing the structural parameters. Specifically, the second capacitor electrode is configured as a metal layer with a doping opening that exposes the first lower metal layer, creating a MIM capacitor structure with higher efficiency and better performance characteristics.
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
This approach reduces the complexity and cost of manufacturing by allowing for simultaneous doping of both transistor and capacitor regions, resulting in a more efficient capacitor with better performance and simplified production processes.
Implementation Method 1
Conductive impurity ions may be doped to the first capacitor electrode in a region corresponding to the doping opening
Data Source
AI summary
An organic light emitting diode display includes a substrate; a first capacitor electrode provided over the substrate and including polysilicon; an insulating layer provided over the first capacitor electrode; and a second capacitor electrode provided over the insulating layer and including a first lower metal layer overlapping with the first capacitor electrode and a first upper metal layer. The first upper metal layer includes a doping opening configured to expose at least a portion of the first lower metal layer.