Wooptix Brings Astronomy Optics to Wafer Metrology
Wooptix‘s technology started with the sun. The Spanish company is based in Tenerife, home to one of the world’s major solar observatories, and much of its R&D team is made up of former astrophysicists. “Have you seen The Big Bang Theory?” asked co-founder and COO Javier Elizalde. “This is our R&D team.”
What they built is a metrology approach that hasn’t been used in semiconductor manufacturing before: wavefront phase imaging (WFPI), derived from adaptive optics for astronomy. Instead of an interferometer, ellipsometer or profilometer, the Phemet system captures the whole wafer in a single snapshot.
One shot, the whole wafer
“With just one snapshot, we are able to see the whole wafer,” Elizalde said. Avoiding scanning saves time and sidesteps vibration. Where a profilometer might measure eight lines across a wafer, Phemet delivers about 16 million data points in one capture, producing nanometer-scale height maps that show shape, global and local stress, nanotopography and in-plane distortion (IPD) (FIGURE 1).
The system measures by analyzing the direction of light as it bounces back from the wafer. “We understand the light, and when the light bounces back, what we are analyzing is the deviation of the light rays,” he said. It currently uses standard commercial LEDs at 590 nm. The IP is in the optics and algorithms. It can see through oxides, nitrides and patterned copper without special preparation. Photoresist is harder because it doesn’t return the light cleanly, Elizalde acknowledged.
A distinctive feature is that the wafer is held vertically, which removes the effect of gravity. That lets Phemet capture the wafer’s free form, which can then be used to predict how it will behave when clamped in a lithography scanner or deposition chamber. “The more information you have on the wafer, and how you can model the wafer when it’s chucked before deposition is done, the better you can see how the wafer is going to behave after deposition or after lithography,” he said. Wooptix spent nearly four years of research on holding a wafer vertically without inducing stress.
Every wafer, every process
The bigger ambition is throughput. Today, fabs typically pull sample wafers to an offline tool. Wooptix’s vision is at least one tool per process step. In advanced logic fabs running 50,000 to 100,000 wafers per month, measuring every wafer could mean two or three tools per process. CMP is a prime example, with many metrology steps that need wafer geometry. “What we are providing is a full signature of the process,” Elizalde said, measured before, after and ideally during each step and fed forward to the next tool.
He was careful to position Phemet alongside existing techniques rather than against them. “That does not mean that we are better than, for example, AFM,” he said. “AFM provides absolute values. We cannot compete with that, but we are complementary.”
Panels are possible too. The technique doesn’t care what it measures, but holding a rectangular panel vertically without stress is a physics problem, and a panel would need larger optics. “It’s doable. It’s more expensive, but it’s doable,” he said, noting the company scaled from 50 mm to 200 mm to 300 mm wafers with no loss of performance. Measuring panels horizontally is straightforward.
On the road to the fab
Wooptix launched Phemet at SEMICON Europa in 2025 and installed the first system at CEA-Leti in Grenoble in May. It is also building its own cleanroom in Tenerife. Elizalde said getting into production fabs takes time. “The road to fab takes more than 12 months,” he said. “That is where we are right now. We think we are achieving that, but it takes time.”
Editor’s note: In the interest of efficiency and timeliness, this article was drafted with the help of AI (Claude, from Anthropic), working from a recording of an interview arranged by Bodewell Group and the company’s press materials. It was reviewed and edited by Semiconductor Digest.
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