Multi-probe Inspection for Light Emitting Devices
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Solution Overview
Problem
The manufacturing process of semiconductor light emitting devices lacks an efficient inspection method to identify defects and measure optical characteristics, which affects the reliability and quality of the final products.
Innovation Solution
A method involving the formation of light emitting devices with first to third cells emitting different colors, where test power is supplied using a multi-probe and images are acquired with an image sensor to identify normal devices by comparing with reference images, followed by precise measurement of optical characteristics using absolute physical quantities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional inspection methods are used for light emitting devices, then each device must be inspected individually, but this results in low inspection efficiency and increased inspection time
Solution Approach 1:
The patent combines multiple inspection functions into a single integrated system. The multi-probe simultaneously supplies test power to multiple light emitting devices, while the image sensor captures images of all devices at once. This merging of inspection operations for multiple devices into a single process dramatically improves inspection efficiency and reduces total inspection time compared to individual device inspection.
Solution Approach 2:
The inspection system is designed with multi-functionality to handle various inspection tasks simultaneously. The same system infrastructure (multi-probe, image sensor, processing unit) can inspect multiple devices with different configurations (single-color, multi-color, different wavelengths) using a universal approach, thereby improving productivity without requiring separate inspection systems for each device type.
2Measurement precision
If comprehensive optical characteristic measurements are performed on all light emitting devices, then measurement precision is improved, but this increases inspection time and reduces productivity
Solution Approach 1:
The inspection process is segmented into two distinct stages: first, a rapid defect detection stage using image capture and comparison that quickly identifies defective devices; second, a precise optical characteristic measurement stage that is performed only on non-defective devices. This segmentation ensures that comprehensive measurements are applied selectively rather than universally, maintaining measurement precision for qualifying devices while improving overall productivity by avoiding unnecessary measurements on defective units.
Solution Approach 2:
The system performs partial inspection actions on all devices (rapid image-based defect detection) and excessive/comprehensive actions only where needed (detailed optical measurements only on non-defective devices). This approach ensures that full measurement precision is applied to devices that warrant it while avoiding the time cost of comprehensive measurements on devices that will ultimately be rejected anyway.
3Productivity
If multiple light emitting cells are inspected simultaneously using a single image sensor, then inspection efficiency is improved, but it becomes difficult to independently evaluate each cell's performance
Solution Approach 1:
The inspection system segments the evaluation process into device-level defect detection and cell-level performance evaluation. The image sensor captures images of multiple devices simultaneously for rapid defect screening. For non-defective devices, the system then performs separate, independent optical measurements on each light emitting cell to evaluate their individual characteristics. This segmented approach maintains both inspection efficiency at the device level and measurement precision at the cell level.
Solution Approach 2:
The system uses an intermediary measurement approach where the image sensor serves as a preliminary screening tool that identifies defective devices. For devices that pass the initial screen, a second measurement stage uses dedicated optical measurement capabilities to independently evaluate each light emitting cell's performance. This intermediary process allows simultaneous inspection of multiple devices while preserving the ability to independently assess each cell's 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 enhances inspection efficiency, reduces unnecessary inspection time, and improves the reliability of light emitting devices by distinguishing defective units quickly and accurately.
Implementation Method 1
acquiring an image from the light emitted from the portion of the light emitting devices to which the test power is supplied using an image sensor
Data Source
AI summary
A method of manufacturing a light emitting device includes forming light emitting devices on a support portion, each of the light emitting devices including first to third light emitting cells respectively emitting light of different colors; supplying test power to at least a portion of the light emitting devices using a multi-probe; acquiring an image from the light emitted from the portion of the light emitting devices to which the test power is supplied using an image sensor; identifying normal light emitting devices of the portion of the light emitting devices by determining whether a defect is present in each of the light emitting devices of the portion of the light emitting devices by comparing the image acquired by the image sensor with a reference image; and based on the identifying step, measuring optical characteristics of each of the light emitting devices identified as normal of the portion of the light emitting devices.