Continous in-line horizontal diffusion furnace
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For semiconductor processes, vertical tube furnaces
and horizontal tube furnaces are usually operated in a batch mode.
The wafers are loaded in a boat, the boat moves into the furnace tube, the process is performed,
the boat is pulled out and the wafers are unloaded.
Alternatively a conveyor furnace, using some transportation band in order to carry samples through the furnace tunnel can be used. However these conveyor furnace are not so clean and using gases like POCl3 for doping is not possible.
For semiconductor applications, state of the art is the usage of tube furnaces, nowadays mainly vertical furnaces. For electronic or solar applications, conveyor furnaces have been used to save costs.
Now Koyo developed a new furnace type in order to merge the benefits of both furnaces and reduce the costs in parallel: Koyo developed a new inline tube furnace! The wafers are carried through the tube on quartz cars with a load of 100 wafers each. The design of the cars is critical in order to obtain a good temperature uniformity and the process results of the POCl3 doping is therefore also affected seriously. Gas curtains at both ends of the tube separate the process room from the environment.
The advantages of this type of construction are obvious:
Developed originally for phosphorous doping of solar cells by using POCl3 in an in-line continuous furnace, this system can be used also for other semiconductor processes if process time is not too long.
Koyo Thermo Systems and Crystec will be pleased to engineer a cost effective system to satisfy your most demanding and exacting requirements.