Resumen
[0001] A high throughput reactor for the mass production of wafers through chemical vapor deposition, mainly to form silicon epitaxies for the photovoltaic industry, is described. main innovation is a high susceptor stacking density: several graphite susceptors are placed vertically and parallel to one another, electrically interconnected, and are heated by Joule effect. Electrical current gets to the susceptors from the current source through specially designed feedthroughs, which connect the cold room outside the deposition chamber with the hot susceptors. Gas flows vertically between susceptors. The substrates on which deposition occurs are placed on the susceptors. Below the susceptors a pre-chamber is found, in which entering gas calms down and distributes homogeneously. Susceptors and pre-chamber are placed inside a stainless steel chamber, which is internally covered by a reflecting material, and externally kept cold by water. Both susceptors and pre-chamber are fixed to a connection panel, which also contains electrical feedthroughs, thermocouple feedthroughs, and gas inlet and outlet. Outlet gases are partially recycled, with the corresponding gas savings and increased deposition efficiency.
Reivindicaciones
1. Epitaxial reactor for the mass production of wafers, which consists of a tight chamber, externally water cooled and internally covered by reflective material, which is coupled to a gas recycling system and which contains: a variable number of stacked, vertical and parallel susceptors, heated by Joule effect; semiconductor plates on the susceptors held to them by pieces of their same material; a fixed connection panel, where electrical and thermocouple connections, and gas inlet and outlet are found; and to which a pre-chamber is fixed by screwing, welding or similar; and a housing which slides on rails to open and close the chamber by uncoupling or coupling to the connection panel. 2. Epitaxial reactor for the mass production of wafers, according to claim 1, characterized by the gas entering the tight chamber directly at the pre-chamber, crossing it vertically upwards and flowing between the susceptors, leaving the chamber through a gas output duct, assisted by the upper chamber wall being tilted towards the output. 3. Epitaxial reactor for the mass production of wafers, according to claim 1, characterized by the susceptors being parallelepiped with trapezoidal section, being wider in their base and thinner in their upper side, and by their being connected to the fixed connection panel by electrical connections. 4. Epitaxial reactor for the mass production of wafers, according to claim 1, characterized by the connection panel having two seals, with the space in between held in vacuum, and a pressure control system coupled to the space between the seals. 5. Epitaxial reactor for the mass production of wafers, according to claim 1, characterized by the pre-chamber containing, on one hand, hollow columns holding its structure, allocating hollow ceramic tubes on which susceptors stand, and thermocouples, whose cables are kept in an inert atmosphere until they reach the outer side, and containing, on the other hand, a gas distributor to distribute the inlet gas throughout the space below the susceptors in a laminar regime, and, finally, an upper wall consisting of or covered by reflective material, that reflects the radiation emitted by the susceptors placed just above the pre-chamber. 6. Epitaxial reactor for the mass production of wafers, according to claim 1, characterized the electrical connections connecting very hot susceptors to standard electrical feedthroughs that cannot stand high temperatures, with a temperature difference higher than 600 °C between them, and which are constituted by a thick, highly radiating prolongation of the same conductive material as the susceptors, coupled to a housing coming out of the connection panel, with internal absorbent walls and external water cooling. 7. Epitaxial reactor for the mass production of wafers, according to claim 1, characterized by being assembled to a gas recycling system that extracts gases from the chamber and re-injects them again totally or partially, that also includes a heat exchanger at the reactor gas outlet, an extraction pump for a fraction of the gases, and a gas blower, for the case of noin situ source gas production. 8. Epitaxial reactor for the mass production of wafers, according to claim 1, for the case of in situ source gas production, characterized by being assembled to a gas recycling system that includes in situ formation of source gas by means of HCl etching of solid silicon, and also includes a heat exchanger at the outlet of the deposition chamber, a solid silicon etching chamber, another heat exchanger at the outlet of this etching chamber, and initial gas feeding.
