MSc thesis project proposal

MicroLED assembly using LIGHT and FLUIDS

Project outside the university

In collaboration with Holst Centre (Eindhoven, NL)

Microscopic light emitting diodes (microLEDs) are an innovative emissive display technology. Similarly to organic light emitting diodes (OLEDs), microLEDs offer high contrast, high speed, and wide viewing angle. However, they can also deliver a wider color gamut, dramatically higher brightness, significantly reduced power consumption and extended working lifetime, enhanced ruggedness and environmental stability. In addition, microLEDs allow the integration of sensors and circuits, thus enabling thin displays with embedded sensing capabilities suitable for e.g. fingerprint identification and gesture control.

Though there currently is no commonly accepted definition, microLEDs are generally considered to be LEDs with a total surface smaller than 2500 µm2. This corresponds to a 50 µm x 50 µm square die, or a circular die with a diameter of 55 µm. According to this definition, microLEDs are already on market as of today – they were re-unveiled by Sony in 2016, in the form of a small-pitch, large video wall where microLEDS replaced traditional packaged LEDs. The big question for both the LED and display industries is then: how far off is the small-pitch, consumer microLED display? That display could redefine cell phones, smartwatches, TVs, laptops and, more recently, virtual, augmented and mixed reality, and head-mounted devices.

Traditional LEDs – such as the 3030 LED with 3000 µm light source – can be handled by SMT equipment and are available to transfer chip by a die bonder when the size of the light source reaches 100 µm. However the existing equipment for pick & place will face serious accuracy challenges when the size of the light source reduces down to 10 µm. To precisely transfer such microLEDs to target backplanes, the accuracy of the manufacturing equipment is required to be less than ±1.5 µm. The accuracy of existing pick & place transfer equipment is ±34 µm (Multi-chip per Transfer), while flip chip bonders feature an accuracy of ±1.5 µm (single-chip per Transfer), which hardly meets the accuracy requirements of microLED mass transfer. Furthermore, miniaturization of microcomponents significantly challenges throughput speed of traditional pick & place systems. Therefore, mainstream adoption of microLEDs by display industries requires not only the development of an assembly technology capable of high placement accuracy, but also and equally importantly the integration of ultra-fine components at industrially relevant throughput speeds.

To summarize: massive microLED assembly is an inherently complex technological task, but it is undoubtedly THE display technology of the future.

Assignment

This 12-month student projects (with the least period of 9-months) is focusing on developing innovative assembly technologies that would enable parallel assembly of microLEDs using a combination of laser transfer and fluidic self-assembly. The goal will be to investigate and optimize the assembly technology in terms of both reliability and reproducibility for single component transfer to massive, parallel transfer of microLEDs as a step towards industrialization of the process.

Your tasks as project member will be:
• Knowledge acquisition through literature survey and discussion with other team members
• Performing experiments in world-class clean-room labs.
• Analysis of the experimental data and presentation thereof.
• Documenting results in a technical report and taking part in technical meetings, internal seminars/colloquiums.

Requirements

You are an ambitious hands-on MS student from mechanical engineering, materials science or (applied) physics. You have good communication skills in English, you are independent and also a team player. The student assignment will be an internship/graduation project with a total duration of 9 to 12 months. If you are looking forward to working in a challenging atmosphere with highly skilled co-workers, then send us your CV!

Contact

dr. Massimo Mastrangeli

Electronic Components, Technology and Materials Group

Department of Microelectronics

Last modified: 2018-03-26