In the fields of modern high-end manufacturing and precision medicine, excimer lasers are playing an increasingly critical role. Many engineers and researchers, when faced with the need for precision machining or ophthalmic surgery, first think of this device capable of producing short-pulse ultraviolet laser light. But what exactly is an excimer laser? Why has it stood out among numerous laser technologies? This article will provide you with an easy-to-understand practical guide to excimer lasers from four dimensions: principles, core advantages, typical applications, and selection considerations.
Simply put, an excimer laser is a gas laser that uses a mixture of rare gas and halogen gas as its gain medium. Its name comes from "excited dimer," a transient excimer state formed under discharge excitation. The wavelength emitted by this laser typically ranges from 193 nanometers to 351 nanometers, falling within the deep ultraviolet range. Due to its extremely short wavelength and high pulse energy, excimer lasers achieve an extremely small heat-affected zone during material processing, enabling micron-level or even nanometer-level precision treatment.
To understand the capabilities of excimer lasers, we first need to look at their working process. Inside the laser cavity, a mixture of argon, krypton, or xenon gas with halogen gases such as fluorine or chlorine is typically filled. When excited by high-voltage discharge or electron beams, inert gas atoms combine with halogen atoms to form excimers in an excited state. These excimers are highly unstable, with a lifetime of only a few nanoseconds. When they rapidly transition back to the ground state and dissociate, they release a high-energy photon. Since excimers exist only in the excited state and immediately dissociate in the ground state, this ensures continuous population inversion, allowing excimer lasers to efficiently output pulsed laser light.
Unlike solid-state lasers or fiber lasers, the gain medium of excimer lasers is gas, so they have no thermal lens effect, and beam quality remains relatively stable. Meanwhile, the ultraviolet photons they emit carry extremely high energy—a single photon has enough energy to directly break the chemical bonds of most organic materials or metal oxides. This photochemical ablation mechanism, rather than purely photothermal ablation, is the fundamental reason excimer lasers are irreplaceable in precision machining.
The unique performance of excimer lasers has made them a standard configuration in multiple high-tech industries. Whether it is semiconductor manufacturing pursuing nanometer-level linewidths or vision correction surgery pursuing safety and precision, excimer lasers provide reliable solutions. Below, we detail several key areas.
In the semiconductor industry, excimer lasers are the core light source for deep ultraviolet lithography machines. As chip manufacturing processes advance toward 7nm, 5nm, and even smaller nodes, the wavelength of lithography light sources must become increasingly shorter. The 248nm and 193nm deep ultraviolet light emitted by excimer lasers, combined with high numerical aperture projection lenses, can carve extremely fine circuit patterns onto silicon wafers. Additionally, excimer lasers are commonly used in low-temperature polycrystalline silicon annealing processes, where they heat and recrystallize amorphous silicon films in an extremely short time, improving electron mobility—a critical factor for manufacturing high-resolution displays.
Many wafer foundries and panel manufacturers, when evaluating new production lines, focus heavily on the pulse stability and average power of excimer lasers. Because any energy fluctuation could scrap an entire batch of wafers. Therefore, in actual selection, engineers often pay more attention to the energy distribution uniformity and gas fill lifetime of excimer lasers.
In the medical field, the most famous application of excimer lasers is corneal refractive surgery such as LASIK and PRK. Using a 193nm wavelength excimer laser beam, doctors can precisely ablate corneal tissue to change its curvature, thereby correcting myopia, hyperopia, and astigmatism. Because this wavelength offers extremely high ablation precision on corneal tissue without thermal damage to surrounding areas, surgical safety and postoperative recovery speed have been greatly improved.
Currently, excimer lasers from mainstream ophthalmic equipment manufacturers are equipped with high-speed eye tracking systems. When the patient's eye makes tiny movements, the laser emission automatically adjusts its position in sync, ensuring every pulse lands precisely on the target ablation point. This sub-millisecond response capability reflects the system integration strength of excimer laser systems.
Beyond semiconductors and medicine, excimer lasers are widely used in aerospace, precision machinery, and scientific research. For example, when machining cooling film holes on turbine blades of aircraft engines, traditional mechanical drilling tends to produce micro-cracks due to the high depth-to-diameter ratio and material hardness. Excimer lasers, with their cold-processing characteristics, can machine high-quality micro-holes without stress, significantly extending blade lifespan.
In scientific research, excimer lasers are often used as pump sources for dye lasers or OPOs. Their high pulse energy and short wavelength enable efficient excitation of various nonlinear crystals, producing tunable broadband laser light for frontier experiments such as spectral analysis and combustion diagnostics.
Faced with numerous excimer laser brands and models on the market, users often feel confused. When selecting, one should not look at a single parameter alone but should comprehensively consider wavelength, pulse energy, repetition rate, beam size, and operating costs. Below are some practical selection recommendations.
First, you need to clarify the wavelength required for your process. The 193nm wavelength is suitable for high-precision polymer processing and ophthalmic surgery; the 248nm wavelength is commonly used for semiconductor lithography and flexible circuit board drilling; while 308nm and 351nm wavelengths offer advantages in fiber Bragg grating writing and certain metal surface treatments. Choosing the wrong wavelength not only affects processing results but may even damage the workpiece.
Second, pay attention to pulse energy and repetition rate. High pulse energy suits scenarios where a large amount of material needs to be removed in a single pulse, while high repetition rates suit processing needs that pursue high-speed scanning. For example, in the lift-off process of flexible OLED screens, high-repetition-rate excimer lasers are often needed to boost throughput. In ophthalmic surgery, the combination of low energy density and high repetition rate achieves a smoother ablation surface.
Excimer lasers are gas lasers, and their operation involves replenishing and replacing halogen gases. Therefore, users should thoroughly understand the device's gas consumption rate, cavity cleaning cycle, and laser tube lifetime. Some advanced models are equipped with automatic gas management systems that extend gas fill intervals and reduce overall operating costs. Additionally, choosing a service provider with strong localized after-sales support can effectively reduce equipment downtime.
If the budget allows, it is recommended to prioritize complete solutions with stable energy monitoring modules and beam-shaping optical components. This not only helps ensure process consistency but also simplifies the complexity of system integration.
Although excimer laser technology is already quite mature, the industry continues to explore its performance limits. On one hand, by optimizing discharge circuits and gas ratios, researchers are striving to push pulse energy to higher levels to meet the needs of large-aperture optical component processing. On the other hand, increasing the repetition rate to several kilohertz while maintaining narrow linewidth is an important direction in current excimer laser R&D.
At the same time, the lifetime and reliability of excimer lasers are continuously improving. New solid-state switching technologies and long-life cavity coating technologies allow lasers to maintain stable energy output even under months of high-load operation. This holds significant economic value for production lines requiring 24/7 uninterrupted operation.
Of course, excimer lasers also face competition from solid-state ultraviolet lasers. However, in applications requiring extremely high single-pulse energy or specific deep ultraviolet wavelengths, excimer lasers remain an irreplaceable choice.
In summary, excimer lasers hold a solid position in semiconductors, medicine, and high-end manufacturing thanks to their unique short wavelength, high photon energy, and cold-processing characteristics. If you are looking for a light source for precision machining or scientific experiments, we recommend first clarifying your core process requirements, then consulting professional equipment suppliers based on the selection considerations mentioned in this article. If you still have questions about specific excimer laser models or customized needs, feel free to contact us. We will provide one-on-one selection consultation and process testing services to help you find the most suitable excimer laser solution.
