micro LED Inspector

1. Epi Defects = Defective Chips

Crystal dislocations, thickness variations, and non-uniform composition in the Epi layer can lead to low light output, wavelength shifts, and even complete chip failure.

2. Wasted Transfers of Defective Chips

If defective chips are picked during mass transfer, they often go undetected until much later — resulting in material waste, process delays, and reduced yields.

3. Increased Sorting and Inspection Costs

Low-quality Epi wafers require more time and effort in downstream processes to identify and filter out bad dies, ultimately lowering overall productivity.

4. The Earlier, the Better — Cost Impact by Detection Stage

•If defects are detected early at the Epi stage: the loss is limited to just a few cents per chip.

•If defects are discovered after CoW assembly or module integration: the loss can increase to several dollars per chip-and in some cases, 10× or more due to rework, wasted components, and lost throughput.

“Early-stage Epi inspection isn't just smart — it's essential.

As micro LED chips getting super smaller, traditional PL mappers can no longer provide the precision required for accurate Epi inspection. Next-generation inspection demands ultra-fine resolution and advanced analysis to meet the unique challenges of micro LED Epi quality control.

Traditional Epi inspection tools can no longer keep pace with the increasingly compact and complex structure of Micro LEDs. WEVE’s next-generation Epi inspection system breaks through these limitations.

1. Up to 40x Higher Resolution than Conventional Tools

Detect even the slightest defects and non-uniformities that conventional PL mappers fail to capture.

2. From Emission Intensity and Physical Defects to Wavelength and Color Analysis

Despite the ultra-high resolution, the system provides complete data including color coordinates and Wd for every microstructure.

3. Purpose-Built for the Micro LED Era

Not a retrofit of outdated systems — this is a next-generation solution engineered from the ground up for high-resolution Epi inspection.

4. High-Speed, Full-Wafer Inspection with Non-Contact, Non-Destructive Scanning

Rapidly inspects even 6-inch wafers without damage, while preserving every detail.

"Complete inspection of Appearance, PL (PL Intensity, PL Appearance), and Color Difference Analaysis — All in a Single Scan!"

WEVE’s cutting-edge technology enables simultaneous analysis of individual micro LED Appearance, PL (Photoluminescence) Intensity & Appearance, WD, and xyY (Color Coordinates) — all in a single scan.

1. Complete inspection of a 6-inch CoW wafer in under 12 minutes

Bandi, powered by WEVE, leverages high-speed stage control and parallel data processing algorithms to inspect a full 6-inch Chip-on-Wafer (CoW) — containing over 10 million micro LEDs — in less than 12 minutes.
Unlike conventional systems that require separate scans for each inspection category (Appearance, PL, Color), Bandi drastically reduces inspection time by capturing all data in one pass, maximizing productivity.

2. Non-contact, non-destructive, and ultra-high-resolution inspection

The system utilizes laser-based PL and optical appearance inspection in a completely non-contact, non-destructive manner, ensuring zero physical stress or damage to the valuable micro LED wafers. With spatial resolution below 1μm, even the smallest defects can be accurately identified — enabling data-driven process optimization and yield improvement.

3. Simultaneous measurement of shape, emission characteristics, and color coordinates

Bandi is designed to measure Appearance, PL Intensity, PL Emission Patterns, WD, and xyY Color Coordinates simultaneously in a single process. By consolidating what traditionally required multiple steps and equipment, Bandi not only eliminates inefficiencies but also ensures high data integrity across parameters, enabling deeper defect analysis and root cause identification.

With just one scan, Bandi offers complete defect detection and actionable insights for process optimization. This leads to significant reductions in inspection time and cost, while directly contributing to improved product quality and manufacturing yield.

Appearance Inspection Isn’t Enough - Critical Defects Still May Go Undetected

Appearance inspection is fast and intuitive, but it may be misleading. Chips that look flawless on the outside can fail to emit light due to hidden internal defects, while functioning chips are sometimes misjudged as defective due to minor surface variations. Such errors result in missed defects or false positives, directly impacting yield, increasing costs, and causing unnecessary production losses.

Bandi: Complete Defect Detection in a Single Scan

WEVE’s Bandi system goes far beyond traditional appearance-based inspection. In a single high-speed scan, Bandi simultaneously analyzes multiple key parameters, including:

•PL Intensity

•PL Appearance

•xyY Color Coordinate Analysis (WD)

This sophisticated inspection ensures that no defect is overlooked - even the most subtle ones. To address the industry's longstanding skepticism toward PL-based reliability, Bandi underwent rigorous cross-validation with EL (Electroluminescence) inspection, proving near 100% detection accuracy across over 10,000 micro LED samples. Most notably, all short-circuit defects were successfully detected, showcasing its ability to identify even the most complex and critical failures.

Don’t settle for surface-level inspection. Bandi is more than just an inspection tool - it's the beginning of a smart manufacturing process aimed at zero defects.

Actual image

1 : Bandi inspection image

2 : microscope 50X objective image

WEVE and KOPTI has labeled and successfully inspected over 2 million micro LED chips, achieving an exceptional defect detection rate of 99.274% and a repeatability rate of 99.516% - setting a new benchmark in inspection accuracy and reliability. This level of performance was made possible by combining:

•Ultra-high-resolution imaging technology (with sub-micron precision)

•And advanced deep learning algorithms that push the boundaries of automated defect detection.

Smarter Inspection, Superior Results

Our deep learning models are trained on extensive datasets of both defective and functional chips, enabling the system to identify even the smallest anomalies that human inspectors often overlook.

This results in inspection powered by deep learning, offering unmatched consistency, speed, and accuracy, surpassing human capabilities. WEVE’s solution goes beyond being a simple inspection tool; it's an advanced quality intelligence platform that drives true manufacturing excellence.

By leveraging deep learning, our inspection process ensures superior performance, achieving levels of consistency, speed, and accuracy far beyond human potential. WEVE’s platform is not just about inspection; it’s a next-generation tool that leads the way in quality control for manufacturing.