Low Pressure Diffusion System

Application
Low-pressure diffusion is currently considered to be an effective way to effectively improve the conversion efficiency of solar cells. Low-pressure diffusion/scattered oxidation annealing improves the molecular free path of the diffusion source and solves the problems of diffusion depth and uniformity; compared with atmospheric pressure diffusion, it has some significant advantages, such as high productivity, high square resistance, process repeatability, Low source consumption, clean and environmentally friendly, etc. This equipment is mainly used for the diffusion doping and oxidation annealing process of silicon wafers in the manufacture of crystalline silicon solar cells.

Main Features
Mature high-capacity process, loading and unloading system: balanced and symmetrical design to enhance stability;
Rapid cooling furnace body: The latest patented technology makes the furnace body temperature drop to the required temperature quickly, the cooling rate is increased by more than 25%, which can improve the temperature uniformity in the furnace tube obviously;
The exhaust gas is collected by high-efficiency water-cooled condenser to ensure stable and reliable operation of pipes, valves, filters and diaphragm pumps and long maintenance periods;
Stable design of anti-interference source pipeline to reduce square resistance fluctuation caused by disturbance of environmental factors;
MES/CCRM system with complete architecture and outstanding performance.

Main Parameters

Item	Technical Parameter
Process Method	Soft Landing Closed Tube & Low Pressure Diffusion
Effective inner diameter of reaction tube	Ø430mm
Loading capacity：	Vertical loading method：1600pcs/ batch（166mm） , 1400pcs/batch （182mm） , 1200pcs/vatch （210mm） , 1200pcs/batch （230mm） Horizontal loading method：2200pcs/batch（166mm） , 2000pcs/batch （182mm） , 1800pcs/batch（210mm） , 1600pcs/batch （230mm）
Square resistance and uniformity	Intra-piece≤5% Inter-piece≤4% Inter-batch≤3%（166/182mm160Ω）, Intra-piece≤6% Inter-piece≤5% Inter-batch≤4%（210/230mm160Ω）
Heating temperature	Rt 1250°C
Range of working temperature	400 ~ 1100°C
Temperature control	6-point temperature control, internal and external dual-mode control
Heating method	Automatic slope heating and fast constant temperature function
Cooling method	The latest patented technology, 6 temperature zone section control active cooling furnace body
Accuracy and length of constant temperature zone	≤±0.5℃/2100mm（800~1100℃）/≤±1℃/2100mm（600~800℃）
Single point temperature stability	≤±0.5℃/4h（880℃）
Ship delivery method	The SiC cantilever paddle is used for automatic horizontal feeding, and the loading speed is continuously adjustable from 20 to 1000mm/min; Positioning accuracy≤±1 mm；
The ultimate vacuum of the system	20mbar
System air leak rate	The rate of pressure rise after the pump is stopped and the valve is closed:＜ 2 mbar /min .
pressure control method	Closed loop fully automatic
Process control method	Fully automatic, PLC + industrial computer, touch screen operation
Human-computer interaction interface	LCD display, touch operation, process editing, online monitoring, authority management, team management, networking functions
MES	Optional