Polar Light Technologies Partners with Finetech to Develop Next Gen MicroLED Technology

22 October 2024

Polar Light Technologies Partners with Finetech to Develop Next Gen MicroLED Technology

Polar Light Technologies, a leader in the development of microLED, is excited to announce a partnership with Finetech, a globally recognized supplier for sub-micron and high-accuracy die bonding solutions. The collaboration has already yielded significant advancements in micro-LED technologies for next generation AR, HUD and HMD applications.

Berlin and Linköping

Polar Light Technologies has introduced a major breakthrough in display technology by creating novel GaN pyramidal microLEDs that are directly bonded to Indium pads on a silicon chip. This new method, where LEDs are built from the bottom up, avoids the surface damage seen in traditional top-down methods, resulting in much better optical performance.

The special pyramidal shape of these LEDs allows for the creation of very small LEDs that are brighter and more efficient at emitting light by reducing energy losses and increasing their energy efficiency.

To connect these pyramidal microLEDs to silicon substrates, Polar Light Technologies teamed up with Finetech to develop a cold bonding technique that ensures accurate alignment with the electronics. In early trials, this method showed an impressive 85% success rate, proving its potential for large-scale manufacturing.

Pyramidal microLED to enable smaller, brighter and more efficient light emitters

Polar Light’s approach to making display front panels involves a bottom-up fabrication method using atomic layer regrowth. They grow GaN (Gallium Nitride) microLEDs in the shape of pyramids on a SiC (Silicon Carbide) substrate. This method produces high-quality microLEDs as small as 300 nm, without the damage caused by traditional top-down methods. As a result, the devices have near-perfect surfaces, which is crucial for optical properties.

These MicroLED displays can fit the resolution of a full TV screen into an area smaller than 5 mm², with about 1,000 by 1,000 connection points spaced just 5 µm apart. Polar Light’s design also significantly reduces energy use, making these microLEDs highly efficient for next-gen micro displays.

Compared to regular LEDs, the pyramidal microLEDs improve AR system efficiency by 50 to 200 times thanks to better internal and external quantum efficiencies and enhanced light utilization. By minimizing internal electric field interference and optimizing the interaction between charge carriers in the quantum wells, these microLEDs produce more light with sharper, more narrow emission. This makes them ideal for applications like augmented reality (AR) and micro-projectors, where precise light control is important.

Finetech develops cold compression bonding process for pyramidal microLEDs

A complete microLED display consists of three main parts: the front panel (the actual display), the back panel (which includes all the electronics), and the connection between the two. For the process of connecting the front panel to the back panel made of silicon, a modified flip-chip bonding method was used. In this process, the metallized GaN pyramids are precisely aligned and bonded to the Indium pads on the silicon back panel.

Because of differences in how silicon carbide and silicon expand with heat, no heat could be used during the bonding process. Finetech and Polar Light Technologies developed a cold compression bonding method for aligning and bonding MicroLED arrays using an automated FINEPLACER^® femto 2 sub-micron die bonder. This machine ensures excellent process control, with high accuracy in flatness, alignment, and bonding force, which is crucial for connecting the fine-pitch Indium bumps for high-performance displays.

In addition to its precision, the FINEPLACER^® die bonder is flexible enough to scale up production and adapt to new MicroLED technologies. Finetech also provides solutions for handling materials and cleaning with chemical or atmospheric plasma to avoid damage or contamination. This system allows for easy flipping of delicate Indium bump arrays without tweezers, and it ensures the materials are treated before bonding to improve overall quality.

About Finetech

Finetech is a leading equipment manufacturer for sub-micron die bonding and advanced die packaging. Along with manual and semi-automated die bonder systems for quick product development, the company offers micro assembly platforms for fully-automated production.

Finetech helps technology start-ups and industry leaders worldwide to develop and manufacture innovative semiconductor products. Served customers are companies e.g. in the fields of Datacom & Telecom, Industrial Semiconductor, Medical Technology & Life Sciences, Aerospace & Avionics, Automotive & Transportation, Defense & Security, Consumer Electronics, and Academic & Scientific Research.

The modular hardware and software architecture of Finetech’s die bonder systems allows application-specific machine configurations. New processes and technologies can be added via extension modules at any time to ensure optimal process environments for each type of application. Finetech’s cross-system “Prototype-to-Production” approach with a unified module and software platform allows thinking ahead all automation steps as early as the process development stage. This ensures a streamlined transfer of developed processes in all their technological diversity to the production stage and makes Finetech equipment the perfect fit for flexible and cost-efficient product development.

Supported bonding technologies include eutectic soldering, adhesive bonding, thermocompression bonding, thermo-/ultrasonic bonding, sintering, laser-assisted bonding and precision vacuum die bonding. Die bonders by Finetech are used for the precision assembly of flip-chips, photonics and opto-electronics, as well as all kinds of high I/O count applications at chip and wafer level.

Finetech responds flexibly to specific requirements and offers tailor-made solutions to highly demanding customer applications. The company is represented by direct subsidiaries in its core markets and offers on-site application support and advice. It is also represented world-wide by a network of agencies.

Finetech is headquartered in Berlin, Germany, with subsidiaries in the USA, China, Thailand, and Japan.

www.finetech.de