Isolation Structure Patterning for Micro Device Top Electrode Exposure
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Solution Overview
Problem
The manufacturing processes for new types of displays such as micro LED, mini LED, and quantum dot LED displays are complex and costly, necessitating a reduction in manufacturing steps to enhance efficiency and reduce costs.
Innovation Solution
A method involving the use of a low dose exposure of a photoresist layer to adjust its developing rate, followed by controlled development to expose top electrodes of two-terminal micro devices, allowing for the formation of a top conductor pattern that electrically connects the devices, thereby simplifying the process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional display manufacturing processes are used, then manufacturing completeness is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent combines the isolation structure formation and top conductor patterning into a single photoresist layer processing step. By forming a photoresist layer that simultaneously defines both the isolation regions and the top conductor pattern, and then performing one etching process to create both features, the manufacturing process is simplified and the number of process steps is reduced.
2Manufacturing precision
If more manufacturing steps are added to ensure precision, then manufacturing precision improves, but manufacturing time increases
Solution Approach 1:
The patent performs preliminary patterning of the photoresist layer to simultaneously define both the isolation structure regions and the top conductor pattern regions before any etching occurs. This preliminary action ensures that both features are precisely positioned according to the desired final geometry, and the subsequent single etching step transfers both patterns accurately, eliminating the need for multiple alignment and etching steps.
Solution Approach 2:
The photoresist layer is segmented into different functional regions: one portion that will form the isolation structure and another portion that will form the top conductor pattern. This segmentation allows each region to be independently defined and processed with appropriate parameters while maintaining overall pattern precision in a single process flow.
3Reliability
If standard photoresist exposure dose is used, then complete exposure is achieved, but process control margin decreases
Solution Approach 1:
The patent changes the exposure dose parameter from the standard full dose to a reduced dose that is specifically optimized for the combined isolation structure and top conductor pattern formation. This parameter change provides better process control margin because the reduced dose creates a more gradual exposure gradient that is less sensitive to variations in exposure conditions, while still achieving complete pattern definition after development.
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 method improves process control and increases the process margin, leading to reduced manufacturing time and costs while maintaining electrical connectivity between micro devices.
Implementation Method 1
exposing the photoresist layer with a low dose to adjust a developing rate of the photoresist layer
Data Source
AI summary
A method of manufacturing an isolation structure includes: preparing a substrate having a metal electrode pattern; disposing a two-terminal micro device on the substrate, such that a bottom electrode of the two-terminal micro device contacts the metal electrode pattern; forming a photoresist layer to cover the substrate and the two-terminal micro device, in which the photoresist layer has an upper portion and a lateral portion respectively on a top side and a lateral side of the two-terminal micro device, and a height difference between the upper and lateral portions is less than half of the device height; exposing the photoresist layer with a low dose to adjust a developing rate of the photoresist layer; and developing a top side of the exposed photoresist layer at least until a top electrode on the top side of the two-terminal micro device is exposed by the developed photoresist layer.