Semiconductor lithography is at the center of today’s chip industry. The 70-year-old process has evolved tremendously since it was first introduced and now ensures modern silicon is more advanced than ever.
Extreme ultraviolet (EUV) lithography is currently revolutionizing chip production and allowing manufacturers to design the most powerful chips the world has ever seen. But as artificial intelligence (AI), data centers, and even quantum computing demand the chip industry to continue innovating, what could come next? A look at the history of lithography could offer some idea as to the future of this world-changing process.
One glance at the advanced lithography equipment at a facility belonging to chip titans like Intel or TSMC would shock Jay Lathrop, a physicist dubbed the father of lithography. In the mid-1950s, Lathrop turned the lens of his microscope upside down, changing the world in the process. Patented in 1957, his lithography process opened the floodgates for smaller and smaller circuitry and more powerful computers that take up far less space than their predecessors.
Lathrop’s process replaced the bulky vacuum tubes and large transistors computers used in the 1950s. Thanks to lithography, Moore’s Law—the concept which expects the number of transistors in an integrated circuit to double every two years—has become the norm for chip design.
Ironically, Lathrop wasn’t working on a computer when he revolutionized how they are made. He was developing a proximity fuse for a mortar shell commissioned by the U.S. Army and found that existing transistors were too large. So Lathrop, along with his lab partner Jim Nall, developed their own process. Using an inverted microscope, germanium, and a chemical called a photoresist, they discovered they could precisely manufacture miniature transistors with more precision than any other method.
The rest is history.
After Lathrop and Nall filed their patent, Texas Instruments (TI) and Fairchild Semiconductor recognized the importance of miniaturized commercial transistors. Nall joined the latter while Lathrop joined TI, helping guide the progression of the process they created. Notably, Lathrop’s lifelong friend Jack Kilby was about to create the world’s first integrated circuit around the same time.
In the late 1960s, an optics firm called Perkin-Elmer developed a scanner that could not only project a mask onto silicon wafers but also “paint” it with light. This allowed manufacturers to create transistors as small as a micron—an almost impossible reduction from the multi-millimeter transistors of a decade earlier.
From there, chip features continued shrinking at an astonishing rate. By the 1970s, the scanning method was no longer practical and got replaced by steppers that could move light with micron-scale precision.
In the 1980s, U.S. firms started losing market share to Japanese chipmakers, especially in the memory chip segment. In the Netherlands, Philips spun out a unit that would go on to dominate the lithography industry, ASML.
Shortly after, chip demands went beyond the limits of visible light, so manufacturers shifted to using chemicals to create deep ultraviolet light. But even that innovation was outdated by the early 2000s. So lithographers turned to multi-patterning to apply multiple layers on top of each other to create silicon with denser patterns.
In the chip world, sometimes a gutsy investment in an uncertain technology pays dividends. For ASML, betting its future on EUV couldn’t have panned out better.
Though the technology took more than three decades to develop and required billions of dollars of investments, ASML now has the industry cornered.
The technology requires turning a microscopic ball of tin into plasma by shooting it with a carbon dioxide laser. The EUV light emitted by the plasma is then reflected off the world’s flattest mirrors which are just nanometers thick. Actuators and sensors hold the mirrors so still that ASML claims they could direct a laser to hit a golf ball as far away as the moon. This allows for the incredibly precise fabrication at the 5nm node with manufacturers seeking to shrink even further to the 3nm node.
Today, EUV lithography is responsible for the production of the most advanced chips that power smartphones, computers, and data centers. These chips can pack over 10 billion microscopic transistors—and that number continues to grow each year. Still, ASML remains the only company in the world that can supply the machines and expertise needed to produce chips with EUV technology.
With AI increasing demand for cutting-edge data center chips, EUV will continue to play a huge role in the coming decade and beyond. After all, only EUV lithography can fabricate the chips needed to power the data centers housing advanced machine learning algorithms.
But lithography isn’t done yet. ASML aims to release its next generation EUV technology, high-numerical-aperture EUV, in the coming years. The next iteration will let chipmakers pack even more components onto each wafer, enabling chips that will put today’s best microprocessors to shame.
As for what comes after EUV, no one knows. But Moore’s Law and the ever-advancing computing field demand we find a way to continue shrinking transistors.
If the past is any indication, the next big advancement in lithography could be waiting under our noses to be discovered. One lucky break—or more likely a bit of unconventional thinking—could bring it to the forefront.