Micro-LED Wafer Testing Structure Using Capacitive Contact
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Micro-LEDs are prone to damage during testing due to the use of conventional probes, and precise probes that match their small size are difficult to produce, posing a challenge in effective testing without causing harm.
Innovation Solution
A micro-LED wafer testing device with a transparent substrate and through holes containing metal posts and dielectric portions that contact micro-LEDs, allowing for testing without damaging the electrodes, using a capacitive testing method to assess the micro-LEDs' functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional probes are used to test micro-LEDs, then testing can be performed, but the micro-LED electrodes are damaged
Solution Approach 1:
A dielectric portion is introduced as an intermediary between the metal post and the micro-LED electrode. This dielectric layer prevents direct contact that would cause damage, while still enabling capacitive coupling for electrical testing. The intermediary structure resolves the contradiction by allowing testing functionality while eliminating the harmful direct contact effect.
Solution Approach 2:
The invention replaces direct mechanical contact testing with capacitive coupling testing. Instead of using conventional probes that physically touch and potentially damage the electrode, the system uses electric field coupling through the dielectric portion to perform electrical testing, thereby substituting a mechanical contact system with a field-based system that avoids damage.
2Measurement precision
If precise probes are produced to match micro-LED size, then testing accuracy improves, but manufacturing difficulty increases
Solution Approach 1:
The testing structure is segmented into distinct functional components: a transparent substrate, through holes, metal posts, and dielectric portions. This segmentation allows each component to be manufactured separately using standard processes, avoiding the need to fabricate complex integrated precise probes. The segmentation principle resolves the manufacturing difficulty while maintaining testing accuracy through the periodic arrangement of these modular elements.
Solution Approach 2:
The metal posts and dielectric portions serve multiple functions: they provide electrical connection, enable capacitive coupling, and act as structural support. This multi-functionality eliminates the need for specialized precise probes, as the same structure performs both mechanical support and electrical testing functions, thereby improving ease of manufacture while maintaining measurement precision.
3Device complexity
If direct contact testing is used, then simple testing structure is achieved, but signal quality deteriorates due to noise
Solution Approach 1:
The dielectric portion acts as an intermediary that enables capacitive coupling while providing electrical isolation. This intermediary structure improves signal quality by blocking noise and interference from ground paths, while still allowing the necessary electrical signal transmission for testing. The dielectric layer thus resolves the contradiction by maintaining structure simplicity while enhancing signal-to-noise ratio through controlled impedance coupling.
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 solution effectively tests micro-LEDs without damaging their electrodes, enabling precise brightness evaluation and noise reduction, while maintaining a high signal-to-noise ratio through capacitive testing.
Implementation Method 1
Each of the testing elements 120 includes a metal post 121 filled in one of the through holes 130, and a dielectric portion 122 connected to a lower end of the metal post 121
Data Source
AI summary
A micro-LED wafer testing device, being applied to test a micro-LED wafer including a metal substrate and a plurality of micro-LEDs disposed at the metal substrate periodically, includes a transparent substrate, a plurality of through holes disposed at the transparent substrate periodically, and a plurality of testing elements respectively disposed at the through holes. Each of the testing elements includes a metal post filled in one of the through holes, and a dielectric portion connected to a lower end of the metal post. The dielectric portions of the testing elements contact a plurality of contacted members of the micro-LEDs, and a top end of each of the metal posts and the metal substrate are powered to conduct an illustrating test for the contacted members of the micro-LEDs.