Micro Diode Isolation Structure Using Low-Dose Photoresist Exposure
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Solution Overview
Problem
The traditional display manufacturing processes are complex and costly, and there is a need for more efficient methods to produce new types of displays such as micro light-emitting diode displays and quantum dot light-emitting diode displays.
Innovation Solution
A method involving the use of a low dose exposure of a photoresist layer to expose and remove a passivation layer covering micro diodes, followed by forming a conductor pattern to electrically connect the diodes, which includes using a low dose to adjust the developing rate of the photoresist layer and ensuring a controlled eroding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional display manufacturing processes are used, then manufacturing precision is maintained, but device complexity and manufacturing cost increase
Solution Approach 1:
The photoresist layer is divided into different exposure zones with different dose requirements. The first region (over the micro diode) receives a first dose, while the second region (adjacent area) receives a second dose, allowing selective processing of different areas to simplify the overall manufacturing process
Solution Approach 2:
Different regions of the photoresist layer are given different local properties through selective exposure dosing. The first region has different exposure characteristics than the second region, enabling localized control over the isolation structure formation while maintaining overall process simplicity
2Reliability
If full dose exposure is used, then photoresist layer is fully developed, but process margins are reduced and micro diode protection is compromised
Solution Approach 1:
Instead of applying full dose exposure uniformly, the patent applies a partial dose (first dose) to the region over the micro diode, which is sufficient for the intended purpose without over-exposing the area. This partial action maintains process margins and protects the micro diode while still achieving the required isolation structure formation
Solution Approach 2:
The passivation layer is applied beforehand to cover and protect the micro diode during the exposure and development process. This protective layer cushions the micro diode from potential damage during manufacturing, and its selective removal is controlled by the differential exposure dosing strategy
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 simplifies the manufacturing process, reduces costs, and enhances efficiency by increasing process margins and allowing for better protection of micro diodes through the passivation layer.
Implementation Method 1
exposing the photoresist layer with a low dose, in which the low dose is less than half of a full dose of the photoresist layer
Data Source
AI summary
A method of manufacturing an isolation structure includes: preparing a substrate with a micro diode having a top electrode and a bottom electrode that is bonded on a bottom conduction pad on the substrate, in which a passivation layer covers the top electrode and a sidewall of the micro diode; forming a photoresist layer to cover the substrate and the micro diode, in which the photoresist layer has upper and lateral portions respectively on top and lateral sides of the micro diode and having a height difference less than half of a device height of the micro diode; exposing the photoresist layer with a low dose less than half of a full dose of the photoresist layer; eroding the exposed photoresist layer until a top surface of the passivation layer is exposed by the photoresist layer; and removing the passivation layer to expose the top electrode.