Precision processing beyond conventional limits

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Picosecond deep-UV laser systems for the materials, feature sizes and emerging processes that challenge conventional machining.

ns ps fs Energy · precision · deep UV
Why Picosecond Pulses?

High peak power with practical pulse energy

The Picosecond
Advantage

Peak power is determined by how much pulse energy is delivered within the pulse width. A picosecond laser can therefore reach very high peak power without requiring the much larger pulse energy needed by a nanosecond source.

Picosecond operation provides a practical combination of high peak power, useful pulse energy and efficient conversion from IR to UV and deep UV. It supports effective material removal while keeping the laser system considerably more compact than a nanosecond source designed to reach comparable peak power.

ns

Nanosecond

Much more energy required for the same peak power

Because a nanosecond pulse is hundreds or thousands of times longer, reaching the same peak power requires correspondingly greater pulse energy. Generating and handling that energy increases the required gain volume, pump power, cooling, optical aperture and overall system size and cost. Greater optical loading also accelerates degradation of nonlinear crystals, coatings and other optical components. The longer pulse additionally allows more heat to spread into the material.

ps

Picosecond

High peak power without excessive pulse energy

Picosecond pulses reach high peak power with substantially lower pulse energy than nanosecond sources. This enables efficient ablation in a more compact system, reduces the energy load on the optics and limits heat diffusion, helping produce cleaner edges with less melting and recast.

fs

Femtosecond

Excellent confinement, inefficient deep-UV conversion

Femtosecond lasers operate primarily in the IR and green spectral ranges. Further conversion into the UV is highly inefficient and technically difficult, while operation at these converted wavelengths can be considerably less stable. The additional conversion stages also reduce the usable pulse energy and increase the complexity and cost of the system. As a result, commercial femtosecond lasers are rarely used in the UV and are particularly uncommon in the deep-UV range.

Ablation rate of aluminum at 355 nm comparing 70 ps and 10 ps pulses
Experimental results obtained during Passat's internal laser micromachining studies using our 355 nm picosecond laser systems. For a 15 µm aluminum sample, the 10 ps regime shows approximately 2–3× higher material removal per pulse than the 70 ps regime.

Experimental comparison at 355 nm

Why a shorter pulse can remove more material

The graph presents experimental data obtained during Passat's internal laser micromachining studies. The measurements were performed on our own 355 nm picosecond laser systems while drilling a 15 µm aluminum sample.

Across the measured fluence range, a 10 ps pulse removed at least twice as much material per pulse as a 70 ps pulse.

The difference becomes even more pronounced at low fluence. In this region, the 10 ps pulse produced an ablation rate approximately three times higher than the 70 ps pulse. Because the same pulse energy is delivered in a much shorter time, the peak power is higher and the material reaches the ablation regime more efficiently before heat can spread into the surrounding area.

For precision drilling, shorter picosecond pulses can therefore provide faster material removal per pulse, especially close to the ablation threshold.

Why not simply use femtosecond pulses?

Commercial femtosecond lasers are widely available at infrared wavelengths, typically around 1030–1064 nm, but they generally provide substantially lower pulse energy than picosecond systems. This is because only a limited amount of energy can be stored and extracted into an ultrashort femtosecond pulse before nonlinear effects become a limiting factor.

Efficient conversion of femtosecond pulses to deep-UV wavelengths such as 213 nm is technically very challenging, and commercial industrial 213 nm femtosecond laser systems are essentially unavailable.

Picosecond pulses are the practical sweet spot between nanosecond and femtosecond technology, combining high pulse energy with high peak power while remaining suitable for efficient frequency conversion to commercial 213 nm deep-UV lasers.

Deep-UV laser light visible in a prism
213 nm 5.82 eV per photon

Why deep UV?

More Energy Per Photon.
A Smaller Focal Spot.

At 213 nm, each photon carries approximately 5.82 eV. Two-photon absorption can bridge the approximately 9 eV bandgap of fused silica, whereas excitation at 1064 nm requires a much higher-order multiphoton process.

Deep UV can therefore couple energy more efficiently into transparent dielectrics, many ceramics and semiconductor structures. The shorter wavelength also supports tighter focusing, enabling micron-scale features with lower pulse energy and less damage to surrounding material.

Two-photon absorption in fused silica Improved coupling in wide-bandgap materials Micron-scale focusing and features Compact all-solid-state alternative to excimer DUV
Where Industry Is Moving

Smaller · thinner · more integrated

The Next Generation
of Precision Manufacturing

Three millimeter microstructured area on glass Microscope view of the microstructure

All modern technologies are moving toward smaller dimensions. In microelectronics, reducing the size of components also reduces the distance between functional nodes, allowing signals to reach their destinations faster and improving the speed and accuracy of information processing.

This trend extends far beyond electronics. In medicine, for example, minimally invasive instruments, microneedles, implantable sensors and microfluidic diagnostic devices depend on smaller and more precise components to improve performance while reducing trauma to the patient.

These developments require highly accurate microstructures, clean edges, small holes and controlled material removal. Lasers are especially well suited to these tasks because they provide non-contact processing, can be focused into a very small spot, offer precise control of the delivered energy and can machine a wide range of materials while minimizing mechanical stress and thermal damage.

Smaller features

Mechanical tools and long-wavelength beams reach practical limits in diameter, kerf width and placement density.

More difficult materials

Transparent dielectrics, ceramics and superhard materials absorb poorly or crack under conventional processing.

Less tolerance for heat

Thin wafers, coatings and multilayer structures can be damaged by melting, recast and thermal stress.

Cleaner production

Manufacturers seek fewer chemical stages, less tool wear and compact, maintainable equipment.

Future-facing applications

Technologies Where
Passat Lasers Can Lead

The following processes can benefit from picosecond pulse width, high pulse energy, configurable pulse control and wavelengths extending to 213 nm.

Advanced packaging · MEMS · photonics · microfluidics

Precision Drilling of Thin Fused Silica and Glass

Thin glass substrates containing arrays of Through-Glass Vias (TGVs) are becoming an important technology for advanced electronic packaging. They are increasingly used in MEMS devices, RF electronics, photonic packages, chiplet interposers and next-generation AI processors, where precisely positioned microvias provide electrical, optical or fluidic connections through the glass substrate.

Typical substrate thicknesses are approximately 100–300 µm, although commercial glass products can extend from about 100 µm to 1 mm. Depending on the application and manufacturing process, via diameters commonly fall in the range of approximately 20–100 µm.

Current manufacturing approaches

Conventional mechanical drilling cannot be used to produce micron-scale through-holes in thin fused silica and glass substrates. Contact with a mechanical drill introduces localized stress, causing brittle substrates to crack or chip before clean microvias can be formed. As a result, industrial manufacturing relies on laser-based processes.

Direct laser drilling, most commonly performed with CO₂ lasers, where the finished via is produced in a single laser process without chemical etching.
Laser modification followed by chemical etching (LIDE / FLICE), where the laser first modifies the glass and the final via is produced during a selective wet-etching process. This approach can provide smoother sidewalls but requires additional chemical processing and handling.

Direct laser drilling provides the simplest manufacturing route, while laser-assisted etching is mainly used when exceptionally smooth sidewalls are required.

Why Passat 213 nm picosecond drilling is different

Passat 213 nm picosecond lasers combine deep-UV wavelength, high peak power and diffraction-limited beam quality in a compact all-solid-state platform. Their unique advantage is efficient two-photon absorption in transparent wide-bandgap dielectrics such as fused silica, enabling direct drilling of high-quality microvias without the need for absorbing coatings or mandatory chemical post-processing.

Direct mask-free drilling without mandatory chemical post-processing.
Two-photon absorption in fused silica, enabling efficient interaction with transparent wide-bandgap dielectrics and direct drilling of high-quality microvias.
Reduced cracking and edge chipping due to the short picosecond pulse duration.
Diffraction-limited beam quality for tightly focused spots, small holes and accurate positioning.
Excellent suitability for fused silica substrates, which offer higher purity, better thermal stability and lower dielectric loss than many commercial glasses used for advanced TGV packaging.

Why demand for TGV is increasing

Glass is becoming an important alternative to conventional organic package substrates in high-performance electronics. It offers excellent dimensional stability, low dielectric loss for high-speed and RF signals, compatibility with fine interconnect routing and thermal-expansion characteristics that can be selected closer to silicon. These properties make thin glass attractive for chiplet integration, advanced semiconductor packaging, photonic assemblies and compact MEMS devices.

Demand for TGV technology is rapidly increasing as advanced semiconductor packaging moves toward glass interposers. Intel, Samsung Electro-Mechanics and Nippon Electric Glass have all announced commercialization plans and investments supporting volume production of glass substrates for next-generation chip packaging.

Intel
Samsung Electro-Mechanics glass-core announcement
Nippon Electric Glass

Thin films · photonics · functional materials

Pulsed Laser Deposition

PLD transfers material from a laser-ablated target to a substrate and is used for complex oxides, optical coatings, semiconductor layers, sensors and research-scale functional films.

Current approaches and limitations

Most PLD systems use KrF or ArF excimer lasers because their ultraviolet wavelengths are well absorbed by many target materials and can generate the dense ablation plume required for thin-film deposition. However, excimer lasers are bulky gas systems that require halogen-containing gas mixtures, high-voltage discharge equipment, gas circulation and regular maintenance. Their typically multimode beam also limits focusing quality and makes the optical system more difficult to align and maintain.

Where Passat can provide an advantage

Passat offers a compact, all-solid-state alternative at 213 nm. Picosecond pulses provide high peak power with useful pulse energy, while the deep-UV wavelength supports efficient target interaction and stable plasma generation without an excimer gas system. The single-transverse-mode beam can also be focused more precisely than a typical multimode excimer beam.

Double-pulse picosecond operation for improved plasma generation

Passat picosecond lasers are also available in a double-pulse mode, where two ultrashort pulses are separated by approximately 25 ns. This operating mode is particularly attractive for Pulsed Laser Deposition (PLD). The first pulse generates the initial ablation plume containing ions, atoms and neutral particles. The second pulse interacts with the expanding plume, promoting additional ionization of a significant fraction of the remaining neutral species and increasing the ion content of the plasma. As a result, the deposited material can be supplied by a cleaner and more highly ionized plume, while the total amount of ablated material is also increased.

Passat has experimentally investigated the influence of single- and double-pulse picosecond operation on laser ablation. Our studies demonstrated that optimized double-pulse emission can significantly improve material-removal efficiency while maintaining high processing quality. These results provide an experimental foundation for future use of double-pulse picosecond lasers in PLD and other plasma-assisted material-processing technologies.

Related publication:
Comparative Drilling of Materials Using UV and IR Picosecond Lasers Ablation with Single and Double-Pulses Emission

Tooling · electronics · aerospace

Micromachining of Superhard and Brittle Materials

Tungsten carbide, technical ceramics, sapphire, silicon nitride and polycrystalline diamond offer exceptional hardness and wear resistance—but those same properties make small holes and complex features difficult to manufacture.

Current approaches and limitations

EDM works only with conductive materials, can be slow and leaves a modified surface layer. Diamond grinding creates mechanical load, tool wear and chipping. Many ceramics absorb 1064 nm poorly, so infrared processing can require higher fluence or more pulses.

Where Passat can provide an advantage

Deep-UV laser light is absorbed more efficiently by many ceramics and wide-bandgap materials. A smaller focal spot improves resolution, while picosecond pulses limit heat diffusion and reduce cracks, chipping and thermally modified material.

Microelectronics · power devices · photovoltaics

Semiconductor Wafer and Solar-Cell Processing

Wafer dicing and solar-cell separation require narrow kerfs, high positional accuracy and minimal edge damage. The challenge increases for thin silicon and hard, brittle wide-bandgap materials such as SiC and GaN.

Current approaches and limitations

Diamond blades create particles, tool wear and mechanical cracks. Stealth dicing depends on internal transparency and precise focusing. Infrared laser cutting is contactless but can produce a larger heat-affected zone and couples inefficiently into some wide-bandgap materials.

Where Passat can provide an advantage

The 213 nm wavelength provides a smaller focal spot and stronger absorption in many semiconductor and coating materials. Picosecond pulses reduce heat diffusion, helping limit melting, chipping and microcracks in thin wafers and next-generation power devices.

Micro-nozzles · filters · masks · miniature devices

Metallic Microstructures

Modern precision systems require holes, slots, grids and free-form metal features from several tens to several hundreds of micrometres, often in thin foils and miniature parts.

Current approaches and limitations

Mechanical micromachining is limited by tool wear, burrs and feature size. Micro-EDM works only with conductive parts and can be slow. IR lasers may melt edges; nanosecond UV improves resolution but still leaves appreciable thermal effects.

Where Passat can provide an advantage

Picosecond 213 nm operation combines the small focal spot of deep UV with reduced heat diffusion. It can produce narrow cuts and repeatable microholes with less recast, burr formation and edge melting, without mechanical contact or electrode wear.

Thin-film removal · selective processing · surface repair

Local Removal of Thin Coatings

Metallic and functional coatings sometimes need to be removed locally without ablating, melting or otherwise damaging the underlying material. This is especially important for semiconductor wafers, optical components and other sensitive coated surfaces.

Current approaches and limitations

Wet chemistry can affect the entire component and creates chemical waste. Plasma treatment may alter surface chemistry. Direct laser ablation is localized, but the processing window between removing a thin deposited layer and damaging the substrate can be very narrow because the laser beam interacts directly with both materials.

Where Passat can provide an advantage

Passat is investigating an indirect coating-removal method driven primarily by a laser-generated shock wave rather than by direct ablation of the coating. A thin sacrificial absorbing layer is placed in front of the coated sample. In our preliminary experiments, this layer was a 1.8 µm aluminum foil.

The laser energy is deposited within the shallow optical skin depth at the surface of the aluminum. Rapid heating and ablation of this region generate a short, high-amplitude pressure pulse. The resulting shock or stress wave propagates beyond the laser-absorbing region, through the remaining foil and into the coated sample. When the transient tensile stress at the coating–substrate interface exceeds the adhesion strength of the deposited layer, the coating separates from the substrate.

Because the laser beam is absorbed by the sacrificial foil instead of directly irradiating the coating or substrate, the process can delaminate the deposited layer while leaving the underlying material intact. The laser parameters must be selected so that the interfacial stress is high enough to release the coating but remains below the damage threshold of the substrate.

This method is still under development and requires further optimization for different coating and substrate combinations. However, our initial experimental results demonstrate that shock-wave-driven removal of a deposited layer without visible damage to the underlying material is feasible.

Research / future development direction

Future analytical systems · plasma research

Laser-Induced X-Ray Spectroscopy

A high-peak-power pulse focused on a target can form a dense plasma that emits characteristic X-rays. Detecting this emission may provide localized elemental information from metals, minerals, ceramics and composites.

Current approaches and limitations

XRF needs an X-ray tube or isotope source. LIBS is fast and remote but analyzes crowded optical spectra. SEM/EDS offers high spatial resolution but requires expensive vacuum equipment and is unsuitable for rapid analysis of large objects.

Where Passat can provide an advantage

High pulse energy and picosecond peak power are attractive for creating highly ionized plasma in a small volume. The 213 nm wavelength can improve energy coupling. This remains a research direction that may eventually combine localized laser processing and elemental analysis.

Research / future development direction

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