The detection of surface defects (such as scratches, stains, cracks) and internal microstructures (such as circuit layout, transistors) on wafers requires a resolution of micrometers or even sub micrometers. Traditional microscopy systems are difficult to meet the stable focusing requirements under high-speed motion due to issues such as insufficient depth of field and limited field of view.
The autofocus microscopy system tracks the height changes of the wafer surface in real time through laser technology and adjusts the focal length of the objective lens to ensure that the image is always clear.

The wafer may be deformed by hundreds of microns in the manufacturing process, while the minimum depth of field of the traditional objective lens may be less than 1 micron, which leads to defocusing during high-speed imaging. Auto-focusing system (such as "Honghu" system) can adjust the Z-axis position in real time through coaxial laser focusing and 5kHz pulse signal, so as to maintain the focusing stability in high-speed movement and greatly improve the detection efficiency.  
In addition, the large field of view microscope system is suitable for high-resolution cameras (such as 8K linear camera), which reduces the scanning times and further shortens the detection time.

The wafer material is fragile, and traditional contact inspection may introduce damage or pollution. Laser autofocus system completes detection by non-contact way, which avoids the risk brought by physical contact, and is compatible with visible light and short-wave infrared imaging, and adapts to a variety of detection scenarios.

Lithography is a key step in semiconductor manufacturing, and automatic focusing system can monitor the accuracy and consistency of patterns in real time.

Modern auto-focus systems (e.g., the "Honghu" series) employ modular architecture supporting multi-mode imaging configurations, including visible spectrum, infrared imaging, and polarized light/DIC (Differential Interference Contrast) modes. This plug-and-play modularity enables streamlined prototype assembly tailored to specific application requirements. For instance, microscopic imaging systems with multi-band compatibility (400-1300nm spectral range) can concurrently address both routine wafer inspection and specialized material analysis demands in semiconductor manufacturing processes.

Auto-focusing microscope system has become an indispensable technology for wafer inspection through high-precision tracking, non-contact inspection, high-speed response and multi-scene compatibility. It not only improves the efficiency of defect identification and process stability, but also reduces the production cost and defective rate. It is a key tool for semiconductor manufacturing to move towards intelligence and automation.