In the "nanometer theater" of semiconductor manufacturing, the fate of each wafer is rewritten by actions precise to the micrometer level. From lithography exposure to etching and shaping, from thin film deposition to packaging and testing, wafers need to complete hundreds of "rotations" and "alignments" in vacuum chambers, process platforms and transfer channels. Any slight deviation can lead to chip failure. In this invisible "micrometer ballet", wafer aligners are the absolute stars, while the air-bearing rotation axes, wafer handling robots and ceramic forks hidden behind them form the "invisible skeleton" that supports this precise performance. In the wave of China's semiconductor equipment autonomy, Huzhou Prim Semiconductor Co., Ltd. is using technological innovation as a pen to write a new chapter of domestic high-end equipment in this field. 

The wafer aligner is one of the core equipment in the front-end process of semiconductor manufacturing. Its core task is to precisely align the alignment marks on the wafer with the coordinate system of the process equipment before critical processes such as exposure and etching, with an error controlled within 0.1 microns (100 nanometers) - this is equivalent to finding two fine lines spaced 0.07 millimeters apart within the space of a human hair's diameter (about 70 microns) and making them perfectly overlap. 

Conventional calibrators typically use contact positioning, achieving alignment by gently touching the edge marks of the wafer with mechanical probes. However, this approach has two major drawbacks: first, the physical contact between the probe and the wafer may cause damage, especially to thin wafers with a thickness of only tens of micrometers; second, the accumulated dust and particles from multiple contacts can contaminate the wafer surface, affecting the yield of subsequent processes. As advanced manufacturing processes progress towards 3 nanometers and 2 nanometers, the micro-nano structures on the wafer surface become increasingly fragile, making non-contact, high-precision calibration technology an inevitable choice. 

The fifth-generation air-bearing wafer aligner independently developed by Huzhou Prim Semiconductor is a breakthrough precisely addressing this demand. Its core technology lies in the combination of "air-bearing support" and "vision-piezoelectric cooperative positioning": the wafer is suspended on multiple sets of air-bearing supports, with the "air spring" formed by high-speed airflow counteracting gravity to achieve non-contact support (suspension height is only a few micrometers); meanwhile, the high-precision vision system on top (resolution up to 0.5 nanometers) and the piezoelectric ceramic actuators distributed in a ring (displacement control accuracy 0.01 micrometers) work together to complete mark recognition, error calculation and dynamic compensation within 0.1 seconds, ultimately achieving a positioning accuracy of ±0.03 micrometers (30 nanometers), reaching the international first-class level. 

II. Air Floatation Rotating Shaft: Making "Rotation" a Precise Art 

If the wafer aligner is the "positioning brain", then the air-bearing spindle is the "muscle" that drives the wafer to complete the "rotation action". During the wafer alignment process, the equipment needs to rotate the wafer by a specific angle (such as 0°, 90°, 180°, 270°) to ensure that the marks in different directions can be accurately identified; while in etching, deposition and other processes, rotation can also achieve process uniformity control (such as the symmetry optimization of plasma etching). Traditional spindles mostly use ball bearings or hydrostatic bearings, but the friction of ball bearings can cause micro-vibration, and the oil film stability of hydrostatic bearings is affected by temperature and contamination, both of which are difficult to meet the nanometer-level precision requirements. 

Prim Semiconductor's magnetic levitation-air bearing hybrid rotating shaft, through the dual anti-friction design of "magnetic levitation + air film lubrication", reduces the friction coefficient of the rotating shaft to the 10⁻⁷ level (close to "zero friction"). Specifically: 

Radial support: Utilizes active magnetic levitation bearings to adjust the radial clearance in real time (only 0.01-0.02 mm) through electromagnetic force, compensating for the centrifugal force deviation during high-speed rotation (up to 300 revolutions per minute).

Axial support: Combines aerostatic bearings, using compressed air to form a uniform air film between the shaft end and the bearing (air pressure 0.5-0.7 MPa), avoiding metal contact.

Drive system: Integrates high-precision servo motors with harmonic reducers, achieving rotational speed control accuracy of ±0.001 revolutions per minute and angle positioning repeatability better than ±0.005° (approximately 0.087 milliradians).

This design not only resolves the wear issue of traditional bearings (extending the lifespan from several thousand hours to over 100,000 hours), but also by eliminating mechanical vibration, it keeps the wafer position fluctuation within 0.005 micrometers during rotation, providing a "rock-solid" motion platform for calibration and processing. 

III. Wafer Handling Robots: The Leap from "Heavy Lifting" to "Fine Work" 

In the wafer manufacturing line, the wafer handling robot (OHT, Overhead Hoist Transport or EFEM, Equipment Front-End Module) shoulders the significant responsibility of "logistics" connecting different process modules. Although a 12-inch wafer weighs only about 0.2 kilograms, its surface is covered with hundreds of nano-scale device structures. Any tilt (>0.1°), vibration (>10 micrometers/second²), or electrostatic interference during the handling process can lead to scratches, particle contamination, or electrical performance failure. Therefore, the precision requirements for the handling robot are no less than those of a calibrator - the repeat positioning accuracy needs to be ≤±0.02 micrometers, the vibration control ≤5 micrometers/second², and it must be compatible with wafers of different sizes (8 inches/12 inches/18 inches). 

Prim Semiconductor's high-precision atmospheric manipulator has undergone full-chain optimization for the "fragility" of wafer handling: 

Arm structure: Utilizing carbon fiber composite materials (with a density of only 60% that of aluminum alloy but a rigidity 20% higher), combined with a "redundant degree of freedom" design optimized through finite element analysis (7-axis linkage), it achieves decoupling of high-speed movement (maximum speed of 2 meters per second) of the end effector (wafer carrier) and micro-vibration.

End effector: Integrated with "active vibration damping + air floatation support" functions, it uses piezoelectric ceramic actuators to counteract inertial forces in real time during movement, while air pads (at 0.3 MPa pressure) prevent rigid contact with the wafer box (FOUP).

Control system: Equipped with an AI-based adaptive algorithm, it can monitor the wafer position deviation in real time through visual sensors (with an accuracy of 0.01 microns) and dynamically adjust the movement trajectory. Even in complex environments with multiple robotic arms working together, it can maintain stable handling accuracy.

Notably, its latest "ultra-clean" robotic arm, by applying a diamond-like carbon (DLC) coating on the arm surface (with a friction coefficient < 0.05) and incorporating a positive pressure clean chamber design (internal cleanliness Class 1), can control the number of particles generated during handling to less than 5 per cubic foot (the industry average is 20 per cubic foot), significantly reducing the risk of wafer contamination. 

IV. Ceramic Plate Fork: Gentle Protection for Wafers "Held in the Palm of Your Hand" 

In the process of wafer handling and alignment, the choice of end-effector directly affects the safety of the wafer. Traditional metal grippers (such as stainless steel) are prone to static electricity and particle adhesion, and their high hardness (Mohs hardness of about 5-6) may cause scratches on the wafer surface (hardness of about 3-4). Although polymer grippers are soft, they have poor heat resistance (usually <150℃), which cannot meet the requirements of high-temperature processes such as etching and annealing. Ceramic Forks, with their characteristics of "high hardness, low friction, corrosion resistance, and anti-static", have gradually become the preferred choice for high-end equipment. 

The AlN ceramic plate fork of Prim Semiconductor is prepared by hot-pressing sintering process (with density > 99.5%). Its technical highlights are reflected in three aspects: 

Material optimization: By adding 5% yttrium oxide (Y₂O₃) to refine the grain structure, the Vickers hardness is increased to 1800HV (close to that of zirconia ceramics), while maintaining a surface roughness of Ra < 0.02 microns to prevent wafer scratches.

Structural design: The front end of the wafer fork adopts a "curved edge + stepped holding surface" design, which not only increases the contact area with the wafer (reducing pressure) but also reduces stress concentration through the curved transition.

Anti-static treatment: A conductive indium tin oxide (ITO) film with a thickness of approximately 50 nanometers is sputtered on the ceramic surface, with a surface resistivity controlled between 10⁶ and 10⁸ Ω (preventing static accumulation without affecting the electromagnetic compatibility of the wafer).

Test data shows that after continuously holding wafers for 100,000 times, the surface wear of this ceramic wafer fork is only 0.5 microns (far below the industry standard of 2 microns), and no visible scratches are left on the wafer surface. It has been successfully applied in the wafer loading process of EUV lithography machines in 12-inch advanced manufacturing lines. 

Conclusion: China's Semiconductor Precision Equipment's "Microscopic Breakthrough" 

From the "zero-friction rotation" of the gas flotation rotating shaft to the "gentle clamping" of the ceramic plate fork, from the "micron-level logistics" of the wafer handling robot to the "nanometer-level alignment" of the calibrator, Huzhou Primus Semiconductor's technological layout essentially represents a full-chain breakthrough in the "precision chain" of semiconductor manufacturing. In today's global semiconductor equipment market dominated by enterprises from the United States, Europe, and Japan, these "tiny yet crucial" equipment innovations not only fill the technological gap of domestic high-end wafer processing equipment but also, through the "independent research and development + process adaptation" model, have driven the leap of domestic semiconductor equipment from "usable" to "good to use" and "durable". 

When a wafer is calibrated, transported and processed in Primetech's equipment, it carries not only circuit patterns but also the confidence of China's semiconductor industry advancing into the "deep waters". On the nanometer-precision playing field, every technological breakthrough is rewriting the industry's landscape - and this, perhaps, is the most touching footnote to "Made in China".