Alexander Pil
9 December 2020

ALSI has been part of the ASM PT group for six years now. With a wealthy parent company like that, the machine builder from Beuningen has much more budget to spend on development and innovation. It recently launched new technology with which it hopes to make a bid for the memory mass market.

A few months back, just before the second wave arrived, Kees-Jan Leliveld, director of ASM Laser Separation International (ALSI), proudly shared a photo on Linkedin. The image showed his engineering team posing in front of a newly delivered machine for a South Korean customer. Not very special in itself, were it not for the fact that it’s based on new technology that should bring ALSI success in the years to come.

Like many machines from ALSI, the new Laser1205 system is also focused on grooving – a back-end chip production process that removes the brittle top layer from a freshly baked wafer, after which the dies can be sawn loose. A few years ago, ALSI got delayed in developing its 300 mm grooving platform, making it miss the window for the mass volume market. For the larger customers, competitor Disco often gets the order.

However, with its good engineering capabilities, ALSI can conquer enough niche markets. “The classic grooving method is based on a laser with pulses in the order of nanoseconds,” Leliveld says. “The challenge is to minimize the burr – the roughness that forms at the edge of the groove. If too large, problems arise during packaging and, for example, a short circuit can occur. The walls of the groove also need to be steeper and the bottom smoother, so that the saw blade can pass through it more neatly.”

To meet the increased demands of the grooving process, ALSI has put its laser specialists to work. They’ve managed to reduce the pulse width to less than a picosecond. “We had to go through a learning curve for that,” recalls Leliveld. “What wavelength do we use: infrared, green, UV? This requires a lot of coordination with the few laser suppliers available for this segment. Then comes the integration game, such as adapting the optical line to the new type of laser. Finally, you have to develop the process. That’s our profession – making a spot pattern from a single laser beam with which we can realize an optimized process. We succeeded and we’re quite proud of that. Disco has also made several attempts, but they’ve failed to get a better process.”

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ALSI is eager to establish the reference process with its ultra-short-pulse laser. That seems to be going in the right direction for micro-logic chips (such as CPUs and drivers). Leliveld also sees opportunities in the mass memory market. “Memories are becoming increasingly complex, consisting of more and more layers. The traditional separation method is becoming a problem because there’s a lot of brittle low-k material in those chips.” That can be solved by adding a process step to the production that requires a short-pulse laser. “Our solution can provide added value there. It’s a completely new niche to us, but the market is moving towards us. There are currently less than a handful of providers with an alternative – and we’re one of them.”

Leliveld concludes there’s a great need from the fact that memory makers send their samples without much ado. “We do a lot of sampling work, write a report and get feedback very quickly. If they wouldn’t do that, the problem wouldn’t be urgent enough.” With this technology, ALSI is competing with Disco as well. “It’s a tough battle that’s certainly not over yet.”

Memory makers need new technology to cut their dies loose. ALSI is one of less than a handful of providers with an alternative. Credit: ALSI

Green lights

The corona crisis has had its effect in Beuningen. In January, Leliveld still believed 2020 would become a record year for ALSI, but in February, the picture changed completely. “From March onwards, we needed to improvise. There was a lot of uncertainty and the market collapsed. The forecast in April looked very different.” In recent months, it has picked up again. “Asia is back on its feet again. The plans that were in place in January are back on the table and are now being implemented.” ALSI is benefiting from the improved IC market through the rise of 5G, artificial intelligence and the increase in home working and gaming. “After a huge dip, the market is continuing as usual.”

For 2021, ALSI sees many green lights. “That’s pretty schizophrenic,” admits Leliveld. “It’s still doom and gloom here in Europe, but in Asia, corona is less and less an obstacle. In China, for example, domestic flights are already at 90 percent of the pre-corona level. I can’t go to Asia now without going into quarantine for two weeks, but the countries there have mutual agreements about safe travel bubbles.”

ALSI had a close encounter with these travel restrictions when it delivered the new Laser1205 system. “Our Korean customer wasn’t yet up to speed, so we really needed to get someone over there to supervise the installation and implementation,” recounts Leliveld. “We pulled it off, but it took a lot of calling and writing the embassy to emphasize the necessity.” Two ALSI engineers were willing to make several trips. “When they landed in South Korea, they were tested and quarantined in a state hotel for a day. Only then were they allowed to continue.”

ALSI recently delivered its first Laser1205 system based on an ultra-short-pulse laser to a Korean customer. Credit: ALSI

Gallium arsenide

An important goal for 2021 is to become successful with ultra-short-pulse grooving. “The first step is to establish the reference process in micro-logic,” outlines Leliveld. Next up is the memory market. “That’s a longer-term goal. We may be able to sell a few systems in that area in the coming year, but we expect it to really take off in 2022 and 2023.”

ALSI has more irons in the fire. For example, the company is already an established name for chip manufacturers working with gallium arsenide, which is often used in ICs for RF, facial recognition and lidar, for example. It also developed a new dicing process for power chips, together with a European chip manufacturer. Leliveld: “Again by tinkering with the laser and the optics, we’ve obtained a V-shaped beam that ensures a better cutting process. The die has higher mechanical strength, so much so that it surpasses that of conventional sawing.” That’s a critical parameter because it reduces the chance of a chip failing in later process steps or breaking if someone drops his phone.

“For years, we’ve heard people say that we could never achieve that mechanical strength with laser technology,” explains Leliveld. “That’s fighting a losing battle; companies won’t take the step because it might give a lower yield later in the process. Together with that partner, we’ve now created something great that we would of course like to roll out to other power customers.”

ALSI is the ASM PT group’s knowledge center for laser technology. “In the coming years, we’re going to focus on dicing and grooving, but within the semiconductor industry, there are many other applications imaginable for lasers,” Leliveld looks forward. “We’re already preparing for what we can do in 2024, 2025 and beyond. For now, we have our full focus on entering the memory market.”