The Filmetrics F20 Thin-Film Thickness Measurement System: A Three-Decade Journey
In the field of thin-film measurement, the Filmetrics F20 thickness gauge is a highly representative product. From its introduction in 1995 to the present day, it has been on the market for nearly thirty years, with cumulative global shipments long exceeding ten thousand units. It remains a common piece of equipment in many laboratories and production lines. This article explores the origins of the F20, the key changes it has undergone, and its story in China.
I. The Birth of the F20 Thickness Gauge
Before 1995, commercially available instruments for measuring thin-film thickness were prohibitively expensive, typically costing upwards of $50,000. Operating these devices was also complex, requiring specialized training, and measuring a single sample could take anywhere from several minutes to several hours. For many small and medium-sized enterprises and university labs, this barrier to entry was significant. The founding team at Filmetrics recognized this problem. Their idea was straightforward: could they build a thickness gauge that was more affordable, easier to operate, and faster? They believed that if they could, there would be a substantial market for it.
Technically, they chose a path different from traditional ellipsometry, utilizing a miniature fiber-optic spectrometer based on the principle of white-light reflectance spectroscopy. When white light strikes a thin-film surface, the light reflected from the top and bottom surfaces of the film interferes. By analyzing the characteristics of this interference spectrum and combining it with known optical constants of the material, the film thickness could be calculated. This method required no complex mechanical moving parts and no sample preparation. They integrated the core optical components, spectrometer, and electronics into a compact unit, operated via a Windows interface. The F20 thickness gauge was born.
II. Rapid Early Iterations of the F20 (1995-1998)
Following the successful launch and strong sales of the F20, Filmetrics did not rest on its laurels. From 1995 to 1998, both hardware and software underwent continuous improvement.
In 1996, the F20 and the contemporary F30 began supporting the measurement of refractive index (n) and extinction coefficient (k), as well as analyzing the thickness and optical constants of individual layers in multi-layer film stacks. Regarding connectivity, the interface transitioned from the earlier analog card to a standard parallel port, allowing users to connect their own computers for use.
In 1997, technological advancements continued. The F20's measurement capabilities were progressively refined in line with market developments, while Filmetrics also expanded its product line.
1998 was a significant year for the F20. That year, Photonics Spectra magazine awarded the F20 its "Circle of Excellence" award, selecting it as one of the 25 best new products of the year. The same year, the F20 began offering an optional UV spectrometer, extending the wavelength range to 215-670 nm and reducing the minimum measurable thickness from 10 nm down to 3 nm. This marked the early appearance of the F20-UV model in 1998.
Also in 1998, Filmetrics introduced several related products, such as the F40 (which could be attached to a microscope for small-spot measurements) and the F50 (a film thickness mapper with a motorized stage). Although these had different model numbers, their underlying technology shared the same foundation as the F20.
III. Entering the 2000s: Major Upgrades for the F20
In 2001, Filmetrics launched the STMapper, a whole-wafer film thickness imaging system using hyperspectral imaging technology. While this product later won an R&D 100 Award, the main F20 line primarily benefited from the accumulated experience during this period.
In 2000, Filmetrics reached a milestone: the shipment of its 1,000th thickness gauge. According to their statistics at the time, Filmetrics had become one of the highest-volume thickness gauge manufacturers globally.
In 2003, the F20 underwent a major upgrade:
The interface was upgraded from parallel port to USB, adapting to newer computers.
The standard spectrometer was upgraded to Vis-NIR (400-1000 nm), enabling measurement of thicknesses from 15 nm to 50 μm.
An optional NIR near-infrared spectrometer (950-1700 nm) was introduced, allowing measurement from 100 nm to 100 μm.
The F20-EXR was officially launched, equipped with both visible and near-infrared spectrometers, covering a measurement range from 15 nm to 100 μm.
The launch of the F20-EXR was primarily driven by users needing to measure thicker film layers—for example, optical coating customers who often worked with multilayer films tens to one hundred micrometers thick, where the standard F20 was insufficient.
In 2007, another round of upgrades arrived:
The USB interface was upgraded to USB 2.0 High-Speed (480 Mbps).
The UV-Vis spectrometer was upgraded, covering 200-1100 nm, enabling measurement from 1 nm to 40 μm.
The F20-CP (contact probe) model incorporated AutoBaseline technology, which automatically compensated for optical system changes when the probe contacted the sample, improving accuracy and stability.
After this year, the F20 product matrix was largely established, offering various configurations: the base model (visible light), UV version (deep UV), EXR version (visible + NIR), NIR version (NIR), and CP version (contact probe). Users could select the appropriate configuration based on their sample types.
IV. The F20 and the Story of UNICORN
Filmetrics' entry into the Chinese market was not particularly early. In the mid-2000s, some traders brought the F20 into China, but localized technical support was relatively weak. Users who purchased the equipment had to email the US headquarters with questions, encountering inconvenient time differences and language barriers.
In 2012, UNICORN Technology was established in Hong Kong. The founding team had years of experience in the precision measurement field. They saw the market potential for the F20 in China—its compact size, low operating threshold, and competitive pricing made it well-suited for China's rapidly developing semiconductor and optoelectronics industries. After communication with Filmetrics, UNICORN became an authorized distributor for Filmetrics in China.
In the initial years, UNICORN focused on core tasks: providing excellent service. If customers wanted to test the equipment's performance, they offered free sample testing. If customers purchased the equipment, they sent personnel for installation and training. When technical issues arose, they responded and resolved them within hours. UNICORN also actively participated in industry exhibitions, visited university labs for demonstrations, and gradually built a strong reputation.
By around 2016, Filmetrics recognized UNICORN's outstanding market coverage and customer satisfaction, granting them exclusive distribution rights for China. Since then, UNICORN has continued to expand its service network, establishing offices in Shanghai, Dongguan, Tianjin, Chengdu, Suzhou, and Beijing. Currently, they serve over 2,000 customers, including more than 300 universities and research institutes.
V. Joining KLA in 2019
On March 6, 2019, semiconductor inspection equipment company KLA completed its acquisition of Filmetrics. Filmetrics became part of KLA Instruments, with its brands and product lines remaining intact.
For F20 users, the acquisition primarily brought back-end changes. Quality control systems were aligned with KLA's standards, and spare parts supply and the global service network were strengthened. As the exclusive distributor for China, UNICORN also expanded its scope, now able to offer KLA's other products, such as the Alpha-Step stylus profiler and Profilm3D optical profiler, alongside the F20.
VI. The F20 Today: Still in Use, Still Being Updated
Following the acquisition by KLA, the F-series product line did not stand still. In 2024, KLA Instruments introduced the F54-XYT-300, a fully automated 300mm wafer film thickness mapping system with an optional infrared camera for imaging through thinned silicon wafers. Although this product line has undergone model iterations, its underlying technology remains rooted in the foundation laid by the F20: miniature fiber-optic spectrometer, white-light reflectance spectroscopy, and Windows-based software operation.
To this day, cumulative shipments of the F20 have long exceeded ten thousand units. In the industry, it holds a position of high overall cost-performance, low barrier to entry, and proven reliability over an extended period. The F20 can be found in semiconductor fabs measuring photoresist thickness, LED fabs measuring epitaxial film thickness, university labs conducting optical experiments, and the medical device field measuring balloon coating thickness.
Summary
Looking back at the F20's nearly thirty-year journey, I believe the reason for its enduring market presence is simple: it addressed a genuine need, and it did so in a sufficiently straightforward and effective manner. It didn't aim for all-encompassing functionality, but rather focused on reliably measuring "transparent thin-film thickness," making it accessible and easy-to-use for users from diverse backgrounds.
If you currently have thin-film samples that need measurement—whether silicon oxide, photoresist, resin coating, or other materials—consider sending them to UNICORN for a try. They offer free sample testing and free reports, providing a definitive answer on whether the F20 can measure your specific material.
Note: UNICORN Technology (www.unicorn-tech.com) is the exclusive distributor for Filmetrics products in China, offering pre-sales demonstrations, sample testing, installation, training, and after-sales support. Contact number: 400-186-8882. Historical sources: KLA official website (Filmetrics Innovation History page) and Filmetrics official website.
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