The core principle of automatic wafer sorting and tray technology is to recognize the position and quality parameters of wafers through a machine vision system, combined with precision robotic arms and conveyor systems, to achieve full process automation of wafer sorting, positioning, and loading onto designated carriers.
1, Core system composition
1. Machine vision positioning system
Using a high-resolution CCD camera (usually with a resolution of ≥ 5MP) and a telephoto lens, the precise angle (positioning accuracy ± 0.1 °) of the wafer Notch port (V-groove) or Flat edge (flat edge) is identified through image processing algorithms, while detecting defects such as scratches and contamination on the wafer surface.
2. Mechanical transmission module
Vacuum suction cup robotic arm: using ceramic material suction cup (diameter 100-150mm), vacuum pressure range -80~-60kPa, mobile repeat positioning accuracy ≤± 0.05mm
Linear motor drive system: maximum speed of 1.5m/s, acceleration of 2G, ensuring fast and stable transmission
3. Classification and placement mechanism
Multi level sorting slide: guide wafers to different tracks based on test data (such as good/bad products, frequency classification, etc.)
• Precise positioning of the vehicle: The vehicle tray (25 pieces/box standard Cassette) is controlled by a servo motor, and the positioning pin fitting accuracy is ± 0.02mm
2, Workflow
1. Wafer picking up
The robotic arm extracts wafers from the input bin and detects the gripping status through edge contact sensors (pressure sensing range 0.1-1N) to prevent fragments.
2. Visual inspection
Perform a 360 ° rotational scan (with a speed of 10-30rpm) at the inspection station to collect wafer ID codes, center coordinate offsets (usually within a compensation range of ± 2mm), and surface defect data.
3. Classified placement
Place the wafers in the corresponding output bin according to preset classification rules (such as electrical test results, visual defect levels), and support mixed batch management (up to 16 classifications).
3, Key technical parameters
• Processing wafer size: 100-300mm (compatible with 12 inch mainstream production lines)
• Processing speed: 1800-2500 pieces/hour (depending on testing time)
Cleanliness level: Class 1 (ISO 14644-1 standard)
Fragmentation rate:<0.005% (based on SEMI E10 standard)
4, Security protection mechanism
The equipment is equipped with laser scanning area protection (adjustable safety distance of 0.5-3m), emergency stop button (dual circuit hard wire backup), and vacuum pressure automatic retraction protection to prevent wafer falling. Operators must receive specialized equipment training and are strictly prohibited from entering the protective area while the equipment is in operation.
This technology has been widely applied in the semiconductor back-end packaging and testing process. The positioning accuracy of sorting machines from leading domestic equipment manufacturers such as Changchuan Technology and Guangli Technology can reach ± 0.03mm, reaching the international advanced level (data displayed at SEMICON China in 2024).
