As semiconductor technology pushes the limits, "how to cut" has emerged as a key topic in semiconductor packaging, as important as "how to make." Even a circuit diagram drawn precisely with a lithography machine worth hundreds of billions of won can turn a multimillion-won artificial intelligence (AI) semiconductor chip into scrap if a hairline crack appears in the final dicing process.
A Korean company has thrown down the gauntlet in the dicing (wafer cutting) market long dominated by Japan's DISCO. It is ITI, which is pushing "Fine Cut," a laser-based, damage-free cutting technology. Chief Executive Lee Seok-jun, 55, whom we met at the company's headquarters in Anyang, Gyeonggi Province, on Jan. 19, said, "Dicing is no longer a simple back-end finishing step; it's the key that will determine the success or failure of HBM4 (6th-generation high-bandwidth memory) and glass substrates."
Lee graduated from Hanyang University with a degree in mechanical engineering and earned a doctorate in laser processing from Moscow State Technical University in Russia. Based on ultrafine laser expertise built since his days as a researcher at LG Industrial Systems, he founded ITI and led the localization of processing technology for ultrathin glass (UTG) for foldable phones, entering the global supply chain of companies including Samsung Electronics. The industry sees his expertise as capable of creating a breakthrough in the next-generation semiconductor packaging market beyond displays.
Traditional dicing has mainly used methods that cut wafers with a physical blade (wheel), or melt the interior with a laser and then forcefully split them. But things change starting with HBM4. The DRAM chips used in HBM4 are 20–30 μm (micrometers) thick, less than one-fourth the thickness of A4 paper. Cutting such thin chips with a blade easily causes invisible hairline cracks. Even if they look fine right after dicing, those tiny cracks split open in the next process—stacking (bonding) the chips and applying heat—leading to mass defects.
The situation is even more urgent for glass substrates, regarded as a game changer in next-generation packaging. Glass is smoother than silicon and has superior electrical properties, but as a highly brittle material, it is extremely vulnerable to impact. If you apply a blade or strong heat as in conventional methods, microfissures inevitably form across the substrate, which directly leads to substrate failure.
Lee's proposed solution is the "Fine Cut" technology. Instead of grinding or melting the material, it precisely controls laser-induced thermal stress to make it separate on its own. "Fine Cut produces smooth cut faces that require no additional polishing and minimizes particle generation," Lee said, adding, "In particular, for ultrathin HBM4 DRAM dies that are like paper and for shock-prone glass substrates, ITI's damage-free technology is a unique solution that ensures Production yield."
Lee stressed that localizing dicing equipment means more than simple "import substitution." The party that holds the equipment sets the process standards. If you depend on Japanese equipment, you have to meet Production yield only within the methods they define, but if you secure independent dicing technology, the logic goes, corporations in Korea can take the lead in designing costs and Production yield in HBM and glass substrate processes. The following is a Q&A with Lee.
—Why is dicing important in HBM and glass substrate processes?
"Because HBM stacks chips layer by layer, microdamage from cutting carries a high risk of expanding into breakage during subsequent heat-treatment processes. In particular, HBM4's die thickness has become extremely thin, making the limits of existing methods clear. For glass substrates as well, microcracks on the cut face are the key variable that determines overall Production yield."
—What drove Japan's DISCO to monopolize the market, and what are the limits of existing methods?
"DISCO is a company that has seized not just technology but the 'process standards.' However, conventional wheel dicing makes it hard to avoid cracks from physical impact, and stealth dicing, which melts the interior with a laser, also leaves invisible defects. These defects don't 'explode' right after dicing; they become time bombs that go off later in the bonding process."
—What sets ITI's "Fine Cut" apart?
"Rather than grinding or melting, it separates by controlling laser thermal stress. From the cutting stage, it follows a 'born crack-free' concept. There is no need for subsequent polishing, and particles can be minimized. Femtosecond lasers are cited as an alternative, but ultimately what matters is not the laser's speed; it depends on how you control heat and stress."
—So UTG display technology has effectively expanded into semiconductors?
"The know-how accumulated in handling ultrathin glass (UTG) for foldables without damage is the root of ITI's technology. Localizing equipment goes beyond simple import substitution; it means we gain the right to choose processes and design costs. Because glass substrates remain a land of opportunity without a global standard, we want to play a leading role as a company that understands equipment, processes and manufacturing end to end."