MR-MUF
Thanks in large part to HBM, the ultra-fast DRAM that keeps pushing the boundaries of memory technology, artificial intelligence has reached new heights. For this reason, some would regard HBM as an overnight triumph associated with the emergence of generative AI. But in reality, it is the result of a revolution in semiconductor technology that spanned more than ten years of arduous labour and cooperation between various technological specialists.
HBM: A high-performance, high-value device that connects numerous DRAM chips via through-silicon via (TSV) to revolutionise data processing speeds.
Ever since creating the first HBM globally in 2013, SK Hynix has taken the lead in creating subsequent iterations of the technology. The company was the first to mass-produce and distribute HBM3E, the fifth generation of HBM that provides the greatest levels of performance in the industry, in March 2024.
SK Hynix MR MUF
The reason for SK Hynix’s dominance in this field is its long history of developing important packaging technologies like MR-MUF and TSV. The Director of Package Product Development at SK Hynix, Gyujei Lee, was interviewed by the SK Hynix Newsroom to the company’s technological advancements in AI memory packaging.
The method of injecting a liquid protective material between stacked chips and hardening it is known as mass reflow-molded underfill, or MR-MUF. The MR-MUF approach is more successful at dissipating heat than the conventional technique, which involves sandwiching film-like materials between each layer.
What is HBM
HBM Leadership: Bold Packaging Technology and R&D Investment
TSV technology was used by SK Hynix to create the first generation of HBM, a world first for the business in 2013. TSV, a crucial technology that allows HBM products to be produced quickly, entails connecting electrodes that vertically penetrate the holes in the chip’s upper and bottom layers by drilling millions of tiny holes in a DRAM chip.
For almost 20 years, TSV has been touted as a next-generation memory technology that will outperform traditional memory, but it took time to become economically viable. The difficulty of building technical infrastructure and the unpredictability of investment recovery deterred companies from jumping in. “Like a bunch of kids around a big lake, waiting to see who would jump in first,” was how Lee put the scene.
He recalled that “SK Hynix was also one of the companies to hesitate in the beginning.” But SK Hynix is made the decision to obtain TSV technology, which can simultaneously provide top performance and large capacity, and WLP3 technology, which incorporates stacking, in order to get ready for the future market. They therefore decided to take the lead and started conducting research in earnest in the early 2000s.
Wafer-level packaging (WLP): A technology that creates final goods by simultaneously testing and packaging a wafer before it is chopped. It is not the same as the traditional packaging procedure that involves slicing each chip after processing a wafer.
HBM GPU
In order to serve the growing demand for high-performance graphics processing unit (GPU) computing in the 2010s, high-bandwidth near-memory became more and more necessary. In response to this need, SK Hynix started working on a new device that combined WLP and TSV technologies, which eventually resulted in the production of the first HBM. This new product used 40% less power and was more than four times quicker than the best graphics DRAM available at the time, GDDR5. Furthermore, chip stacking allowed the first HBM to significantly reduce the product area.
MR-MUF to Advanced: Promoting HBM
SK Hynix introduced HBM initially, but it didn’t dominate the market until 2019 when it produced HBM2E, the third generation. This was a game-changer for the company since it gave it an edge. But Lee remembers the many hiccups along the way to achieving success.
After creating the first HBM successfully, SK Hynix to improve its quality and mass production capacity to meet consumer and market demands,” he stated. This prompted us to create a new packaging technology that was supposed to outperform the current one in terms of technical implementation ease and material application stability. However, we unexpectedly ran into reliability issues early on and had to make a fresh discovery.
In accordance with its technology strategy, the company was also developing MR-MUF technology at that time. Leaders from the relevant departments expeditiously examined simulation results and technology-related data to confirm the dependability of MR-MUF, persuading both management and consumers in the process. Thus, the technology might be quickly implemented for HBM2E.
They were successful in introducing our novel MR-MUF technology to the market because management and clients supported SK Hynix development team,” Lee added. This allows large-scale production and delivery of HBM2E, ensuring consistent performance and quality.
The MR-MUF application made HBM2E a revolutionary product in the HBM market. Thus, it is evident that MR-MUF was important in enabling SK Hynix to achieve its “HBM success story.”
In 2023, SK Hynix continued to establish itself as the industry leader in HBM by first creating the 12-layer HBM and then creating HBM3E, the fifth generation of HBM. Lee and the development team think that the creation of Advanced MR-MUF, an enhanced variant of the current MR-MUF technology, played a major role in these achievements.
5Advanced Mass Reflow-Molded Underfill (MR-MUF): This next generation of MR-MUF technology features new protective materials for better heat dissipation, and it can stack chips 40% thinner than prior generations of HBM devices without warpage.
“The increased number of stacked chips in the 12-layer HBM3 required enhanced heat dissipation performance,” He explained. Specifically, using the current MR-MUF approach to address the warpage issue of the thinner chips in the 12-layer HBM3 was difficult.
SK Hynix created an enhanced version of the current MR-MUF technology, called Advanced MR-MUF, to get beyond these restrictions. As a result, the first 12-layer HBM3 in history was successfully developed and produced in large quantities in 2023. In March 2024, the world’s best-performing HBM3E was produced in large quantities. Additionally, the 12-layer HBM3E, which will be given to significant AI businesses starting in the second half of this year, uses Advanced MR-MUF. As time goes on, more uses for Advanced MR-MUF will be found, enhancing SK Hynix’s position as a leader in HBM technology.
There was a recent industry rumour stating that MR-MUF implementation is challenging. In order to get around this, concentrated on telling them that MR-MUF is the best technology for high stacking, and ultimately gained their trust again.
The Secret to Custom Product Development: Next-Gen Tech and Customer Partnerships
Together with the core HBM technical staff of SK Hynix, Lee received the 2024 SUPEX Award6, the highest honour bestowed by the SK Group, in June 2024, in recognition of his longstanding contributions to HBM development. “It is thanks to the efforts of many members who have worked as one team to make the product a success,” Lee stated in response to collecting the prize.
The most prestigious honour in the SK Group, the 6SUPEX honour, signifies “super excellent” and honours members who have successfully implemented innovations by taking on new difficulties without fear.
But there’s no room for complacency or satisfaction, according to Lee. He underlined the significance of timely development of various next-generation packaging technologies to fulfil the ever-increasing demand for customised goods in order for SK Hynix to continue its HBM leadership in the future.
The speaker mentioned that next-generation packaging technologies, including hybrid bonding, have garnered attention lately for their ability to stack chips higher for enhanced performance and capacity, all while keeping product thickness in compliance with standard criteria. The smaller space between the chips makes heat regulation more difficult, but these new packaging technologies should address the problem and satisfy consumers’ progressively varied performance requirements.
Hybrid Bonding: A method that attaches chips to one another directly, eliminating any gaps. In order to facilitate high-layer stacking, this lowers the chip’s total thickness. For HBM products with 16 layers or more, this is being explored. Both the hybrid bonding technology and the Advanced MR-MUF are presently being reviewed by SK Hynix.
“SK Hynix will continue to secure new technologies and improve its current Advanced MR-MUF with excellent heat dissipation performance.”
Finally, Lee underlined that SK Hynix‘s competitive advantage and one of its strengths is strong communication and engagement with customers, which the business should keep enhancing going forward.
“He believe that SK Hynix’s ability to quickly deliver high-quality products with mass production competitiveness to customers when there was actual demand is the biggest driving force behind its dominance in the HBM market,” the speaker stated. The achievement of this has been made feasible not just by technological prowess but also by SK Hynix on going consumer communication.
Additionally, package development team responds quickly to stakeholder and consumer needs, incorporating them into features of a products. Together with SK Hynix special collaborative culture, He believe this endeavour will make us a formidable force in any circumstance. He will persist in imparting my credo, “move cautiously, feel together,” to their staff as a get ready for SK Hynix Packaging’s future.
