As the micro/nano manufacturing industry rapidly evolves, etching has become a core process for micro/nano structure fabrication and directly determines device precision, performance and reliability. Etching foundry services, with professional process capability and flexible adaptation, support research institutions and enterprises in realizing micro/nano structure production while reducing R&D and manufacturing costs. Anisotropic etching and isotropic etching are two core methods with very different process characteristics, and together they serve a wide range of application scenarios.
The core value of etching foundry services is to accurately transfer photoresist patterns onto the substrate surface through professional process control, selectively removing material and building the required micro/nano structures. Whether the task is basic patterning or fabrication of high-aspect-ratio and complex 3D structures, etching foundry can balance precision, efficiency and cost through parameter optimization. The different principles and applications of anisotropic and isotropic etching provide flexible solutions for many types of structures.
Anisotropic etching focuses on directional precision. The etching rate varies significantly in different directions, with the vertical etching rate much higher than the lateral rate, resulting in steep etching profiles. It is achieved through process-mechanism control, such as directional plasma bombardment or the use of crystallographic differences in materials. In foundry practice, dry etching is commonly used, and parameters such as plasma density and ion energy are adjusted to precisely control etching rate and selectivity.
The advantage of anisotropic etching lies in high precision and strong pattern fidelity, with little lateral undercut. It is suitable for nanoscale fine patterns and high-aspect-ratio structures. In advanced semiconductor manufacturing, it can be used for FinFET fins and 3D NAND channel holes, enabling precision structures with aspect ratios above 30:1. In MEMS device manufacturing, it suits narrow-gap structures in accelerometers and gyroscopes. In advanced packaging, it can form through-silicon vias for vertical interconnection. It also helps solve etching challenges in third-generation semiconductor materials such as silicon carbide and gallium nitride for power devices.
Unlike anisotropic etching, isotropic etching is characterized by uniform material removal in all directions, creating rounded profiles. It is commonly implemented as wet etching, where chemical solutions dissolve unprotected areas of the material. Etching rate and selectivity are controlled by adjusting solution concentration and temperature.
Isotropic etching is simple, low-cost, fast and highly selective, making it suitable for batch processing and applications where efficiency and cost are more important than extreme dimensional precision. Typical uses include silicon wafer thinning, metal-film etching and non-critical dimension pattern transfer. In microfluidic chips, it can create rounded microchannels to reduce fluid resistance. In semiconductor packaging, it can remove metal-interconnect residues. It can also be used for single-crystal silicon surface polishing and repair, providing a good base for subsequent processing.
In etching foundry services, the two methods are complementary and should be selected according to customer requirements. A professional foundry will design a process based on structure size, precision requirements, material properties and cost budget. Process optimization can also compensate for limitations, such as suppressing lateral undercut in isotropic etching or reducing substrate damage during anisotropic etching.
As micro/nano manufacturing develops toward 3D integration, higher integration and finer structures, etching foundry services are becoming increasingly important. Anisotropic and isotropic etching meet needs across semiconductors, MEMS, microfluidics and other fields. In the future, etching foundry will continue to deepen process innovation, promote combined use of both methods, improve precision and efficiency, reduce cost, and support high-quality development and industrial application of micro/nano devices.
