The analysis technology for solid components has important applications in fields such as chemistry, materials science, and geology. By analyzing specific elements or isotopes in a sample, we can accurately evaluate and analyze the processing technology and age of the sample. Mass spectrometry (MS) is a commonly used solid-state analytical technique. It identifies the types and contents of chemical components in the sample by measuring the mass-to-charge ratios of ions excited from the sample surface.

Laser ionization mass spectrometry (LIMS) combines laser and mass spectrometry techniques. When the sample is irradiated with a laser, the atoms and molecules on the surface of the sample absorb energy and undergo ionization. The generated ions are then detected and analyzed using a mass spectrometer. Over the last century, LIMS has rarely been applied because of the limited performance of lasers and instruments. However, with the emergence of femtosecond lasers and innovative instruments, LIMS can satisfy the requirements of high-accuracy element analysis and high-resolution element imaging. Compared to other mass spectrometry techniques, LIMS has the following advantages: 1) direct analysis of samples without the need for complicated preparation; 2) high utilization rate of the sample and minimal damage to the sample surface; 3) reduced sample damage and matrix effects because of the use of ultrashort pulse lasers (such as femtosecond lasers). These characteristics are beneficial for the direct semi-quantitative analysis of unknown samples without standards.

In the past few decades, numerous studies have thoroughly investigated the performance of LIMS, covering a range of topics, from the theory of laser–solid interactions to the impacts of various laser parameters and instrument configurations on the final test results. Investigations have also extended to the analysis of industrial technologies and geological samples, leading to significant advancements in this field. Therefore, it is essential to summarize the existing research and provide an outlook for future developments.

First, the principle of laser-solid interactions and the differences between nanosecond and femtosecond lasers in their interactions with solids (Fig. 3) are briefly introduced, Thereafter, the influence of laser parameters on laser ablation, including laser power density, wavelength, and pulse duration, is discussed. A brief overview of commonly used mass spectrometry techniques is introduced (Fig. 8 and Table 1), with a particular focus on two high-resolution mass spectrometry techniques that are easily coupled with laser systems: time-of-flight mass spectrometry (TOF-MS) and electrostatic ion trap mass spectrometry. The basic principles and advancements in these two instruments are introduced.

The application of LIMS to solid analysis is then discussed. A new LIMS system developed by Bern University is presented, with a comprehensive analysis of its instrument design (Fig. 15) and performance, demonstrating its capability for solid elemental detection. A double-pulse LIMS instrument introduced in 2018, which offers higher resolution than conventional systems, has been validated for metal thin-film detection. Other LIMS studies have demonstrated the potential of this technology for metal and alloy samples.

In addition, a series of experiments have been conducted on semiconductor industry technologies, such as Cu interconnects and through-silicon via (TSV). By using LIMS scan and depth analysis, better ways to reduce contaminants in semiconductors and the necessary information for a better understanding of the mechanism and process of TSV filling are provided. LIMS has also been used to analyze geological and planetary samples. Information on ancient oceanic properties and rock characteristics can be obtained by studying the properties of micrometer-sized inclusions and filamentous structures in rocks. The analysis of biologically related elements (C, H, O, N, Fe, etc.) in planetary samples can provide evidence for the existence of life on planets.

After decades of development, LIMS has gradually matured and become a powerful tool for solid analysis, with detection capabilities comparable to or surpassing those of any mass analysis technology available today. Compared with the nanosecond laser, the femtosecond laser has a lower dependence on wavelength and material and is able to reduce matrix effects, minimize thermal effects, and produce smaller and more limited ablation craters, thus achieving a higher resolution. Experiments have shown that under the same conditions, an ultraviolet laser can further reduce matrix effects, improve spatial resolution, and increase ion yield compared to longer-wavelength lasers. With technological advancements, artificial intelligence (AI) has become a part of our society. In the future, a combination of AI and LIMS is expected. By combining AI with LIMS, complex datasets can be analyzed using big data, real-time changes to LIMS instrument parameters can be made, and the detection capability for complex and heterostructure samples can be improved.