In this masterclass Dr Gareth Jones, Director of Business Development (Photonics) will provide a detailed view of the processes and requirements for growing high quality epitaxial materials for photonics products – in particular MicroLEDs. The talk will be focussed on the epitaxial growth process on large wafer sizes suitable for integration into Silicon foundries, for example, for CMOS backplane integration.

The microLED revolution is poised to transform display technology by offering unparalleled visual performance, enhanced energy efficiency, and compact form factors across a spectrum of applications, from large area displays to wearable augmented and virtual reality devices. The small pixel size but large device footprint creates unique challenges across the device supply chain.

Development of strong partnerships between epitaxial wafers suppliers, like IQE, and device processing and fabrication as well as packaging and integration is a key priority to overcome the significant challenges to getting microLED technology into consumer markets and ensure the future of display technologies.

Enabling greater awareness of the choices, opportunities and challenges at the epitaxial wafer level and how this can then affect subsequent wafer and device fabrication stages is an essential part of integration of the supply chain considerations for these challenging products.

Currently, two main materials systems are utilised in the LEDs in microLED displays, which are AlGaInP grown on GaAs (or Ge) and GaN grown on sapphire, SiC or Si. These will be explored in detail, in terms of the Metal Organic Chemical Vapour Deposition (MOCVD) processes, device layer structures and how these then determine the subsequent device behaviour, such as external quantum efficiency, forward voltage, emission wavelength and FWHM, and the efficiency of device processing.

This masterclass will ideally suit device engineers and designers, microLED product managers and those interested in understanding the benefits and limitations of the epitaxial wafers that are the key enabling upstream technologies of the microLED device supply chain.

About Company: IQE is the world’s only pure play compound semiconductor epitaxy provider with a global footprint, strategically positioned to enable the next wave of innovation. It provides customers in their geographies with three-continent manufacturing services, offering world-class technology, flexibility and supply chain security.

Manufacturing microLED-based displays involves the precise assembly of millions of pixels onto a backplane. For a 4K display, approximately 20 million microLEDs must be accurately positioned and bonded to the target substrate. The display technology is highly demanding, as even a single malfunctioning pixel can be noticeable to the end user. Effectively handling a large quantity of small microLED chips while maintaining accuracy across expansive display areas poses a significant manufacturing challenge. The challenge lies in handling a large quantity of small microLED chips while maintaining accuracy across expansive display areas. With many distinct components, achieving a high yield is crucial to delivering a fully operational microLED display. Therefore, developing a transfer method for assembling microLED displays that is both rapid and precise on an industrial scale while enabling efficient rework is paramount. Various innovative solutions, pushing the boundaries of what is possible, have been developed by the academic community and industry, falling into two broad categories: mass-transfer technology and monolithic integration, each presenting unique advantages and challenges.

In this masterclass, we will delve into an overview of prevalent and advanced mass transfer technologies, including micro-transfer printing, diverse laser-assisted transfer techniques, and fluid self-assembly approaches, will be provided. A comparative analysis will be conducted to assess the advantages and challenges of these technologies, focusing on transfer throughput and yield, compatibility with manufacturing full-color displays, and enabling cost-effective rework.

Future displays will range from tiny ones, for AR/VR applications, to over 100 inches diagonal, for large wall TVs. Lasers play an essential role in producing state-of-the-art displays especially when it comes to high-end high-resolution displays. This masterclass will cover the laser processes required for microLED display manufacturing. We will present results and beam delivery concepts for Laser Lift-Off, Laser Mass Transfer, and Laser Repair. Further, we will present our latest findings and results about suitable materials and wafer configurations. After the transfer and repair, a final bonding step is required, where our Laser Assisted Bonding shows advantages over reflow ovens. We will present our flexible laser bonding solution.

In this MasterClass, Dr. Tali Hurvitz, InZiv VP of R&D, will present an overview of the key challenges in today’s electro-optical inspection and metrology of microLEDs. The talk will explore the wide diversity in microLED chip designs, including variations in size and geometry of the LED chip and contact pads, wavelength, optical power, luminance, and other properties, and the implications for accurate and high throughput inspection and metrology. Special focus will be placed on the question of electroluminescence (EL) vs. photoluminescence (PL), and the critical information obtained via the study and comparison of IV curves in determining LED health on a per-chip basis. Other topics covered in this analysis include the unique contribution of high-resolution nano-EL and nano-PL measurements, the importance of testing for External Quantum Efficiency (EQE), and the role of angular measurements in fully assessing microLED functionality.