Metal-organic frameworks (MOFs) are crystalline porous materials constructed from metal ions or metal clusters and organic linkers through coordination bonds. MOFs become one of the most actively studied functional porous materials due to their long-range structural order, high porosity, exceptionally large specific surface areas, and tunable pore environments. Researchers can design framework topologies in an atomic level and regulate channel dimensions, pore shapes, and surface chemistry in a nanoscale via selecting metal nodes with different coordination geometries and organic linkers with tailored sizes, conformations, and functional groups. These characteristics endow MOFs with a broad application potential in gas storage, molecular separation, heterogeneous catalysis, chemical sensing, optoelectronics, and emerging micro/nano devices. In particular, continuous progress on component design and post-synthetic modification make it possible to modulate the electrical, optical, and interfacial properties of MOFs systems, thereby creating opportunities for their integration into microelectronic, photonic, and sensing platforms.

Despite these advantages, the practical use of MOFs in integrated devices remains strongly limited by their common physical forms. Most of MOFs are still prepared and utilized as polycrystalline powders, bulk crystals, or randomly deposited particles, which are difficult to position precisely on substrates or to incorporate into device architectures with controlled dimensions. As modern microelectronics, integrated photonics, and high-density sensor technologies continue to evolve toward miniaturization, multifunctionality, and on-chip integration, it is important to convert the intrinsic physicochemical properties of MOFs into device-relevant thin films and micro-/nano-structures. In this context, patterning technology plays a central role. It provides an essential bridge between the unique properties of MOFs and the fabrication requirements of practical devices via enabling high-quality MOF films or well-defined micro/nanopatterns to be formed on silicon wafers, glass, metals, and flexible polymer substrates. The development of reliable and precise patterning strategies is thus a key prerequisite for the implementation of MOFs in integrated circuits, sensor arrays, optical components, and other miniaturized functional systems.

However, MOFs also present some distinctive challenges for micro-/nano-fabrication. Their frameworks are mainly stabilized by coordination bonds, which are generally weaker than the covalent or ionic bonds in conventional inorganic semiconductors. As a result, many MOFs possess a limited mechanical robustness and are sensitive to heat, moisture, irradiation, reactive chemicals, and aggressive processing environments. Furthermore, their interconnected nanoporous channels can be easily blocked or damaged during conventional lithographic and etching procedures. Standard microfabrication methods such as plasma etching, wet chemical corrosion, and resist-assisted processing often involve high-energy species or chemical agents that may degrade framework integrity, alter surface functionality, or collapse pore structures. In addition, the compatibility of many MOFs with established semiconductor processing conditions is also insufficient, especially with respect to thermal stability, solvent tolerance, and interface adhesion. These factors motivate the development of MOF-specific patterning methods that can deliver a high spatial precision, while preserving crystallinity, porosity, and functionality.

According to whether the intrinsic structure of the MOF is directly transformed during processing, the existing MOF patterning technologies can be broadly divided into indirect and direct strategies. Indirect patterning does not primarily rely on structural modification of preformed MOFs. Instead, it controls where MOFs nucleate, grow, or deposit through external spatial confinement, surface chemical guidance, or material transfer. Representative approaches include template-assisted growth, inkjet printing, microcontact printing, selective growth on chemically modified substrates, and other spatially guided assembly methods. These routes are attractive because they are relatively simple, often mild, and generally effective for preserving the original porous framework. They play an important role in the early development of patterned MOF films and arrays, especially on nontraditional substrates and in proof-of-concept sensing devices. Nevertheless, their pattern fidelity is often restricted by template dimensions, droplet spreading, solvent evaporation, or interfacial diffusion. As a consequence, it remains difficult for many indirect methods to achieve high-resolution submicron-sized features, excellent film uniformity over large areas, and precise three-dimensional integration. Direct patterning strategies emerge as a major focus of recent research. Unlike indirect routes, they directly process pre-deposited MOF films or their precursor-derived layers through localized irradiation or other targeted energy inputs. Ultraviolet light, electron beams, X-rays, and lasers are the most widely explored tools. Their underlying mechanisms can be generally categorized into two types. The first involves irradiation-induced chemical changes, such as ligand crosslinking, framework decomposition, bond cleavage, or surface functionalization, which create solubility or wettability contrast between exposed and unexposed regions and thus enable selective development. The second involves direct material removal or transformation through physical ablation, decomposition, densification, or phase change. Compared with conventional resist-based lithography, direct patterning often reduces the need for sacrificial organic photoresists and can minimize residue-induced pore blockage. The carefully-designed direct methods can achieve a higher resolution, while retaining a large fraction of the crystallinity, pore accessibility, and chemical functionality of MOFs. Recent studies demonstrate that X-ray and electron-beam lithography can produce features well below 50 nm, ultraviolet-based chemistry can offer an effective balance between resolution and scalable processing, and laser-induced methods can enable localized consolidation, shaping, and even three-dimensional structuring.

From a broader perspective, the evolution of MOF patterning reflects a transition from externally guided deposition toward irradiation-driven in-situ material transformation. This transition is essential for addressing several key demands simultaneously, including precise positioning, high-resolution micro-/nano-structuring, heterogeneous integration, and compatibility with existing device fabrication workflows. Also, patterning requirements for MOFs can be understood as progressive levels of spatial control, i.e., one-dimensional control over film thickness, two-dimensional control over in-plane location and geometry, and three-dimensional control over complex architectures and multilayer arrangements. Expanding from simple film formation to sophisticated three-dimensional pattern construction will be crucial for realizing advanced device concepts in optics, sensing, electronics, and biomedicine.