Systems and methods for epitaxially depositing films on a semiconductor substrate
View Patent ↗Systems and methods for epitaxial deposition. The reactor includes a hot wall process cavity enclosed by a heater system, a thermal insulation system, and chamber walls. The walls of the process cavity may comprises a material having a substantially similar coefficient thermal expansion as the semiconductor substrate, such as quartz and silicon carbide, and may include an isothermal or near isothermal cavity that may be heated to temperatures as high as 1200 degrees C. Process gases may be injected through a plurality of ports, and are capable of achieving a fine level of distribution control of the gas components, including the film source gas, dopant source gas, and carrier gas. The gas supply system includes additional methods of delivering gas to the process cavity, such as through temperature measurement devices, and through a showerhead.
1. A wafer processing system comprising:
a processing chamber containing a substrate holder for receiving at least one semiconductor substrate;
a heating device in communication with the processing chamber;
a plurality of gas inlets for flowing gas into the processing chamber over the surface of a semiconductor substrate, wherein at least certain of the gas inlets are configured to flow a gas over an edge zone on a semiconductor substrate, at least certain of the gas inlets are configured to flow a gas over a middle zone on a semiconductor substrate, and at least certain of the gas inlets are configured to flow a gas over a center zone on a semiconductor substrate;
the plurality of gas inlets include a longitudinal section and a common lateral section that includes a common plenum such that gases flow upwards or downwards through the longitudinal section prior to being directed across the semiconductor substrate by the lateral section;
a gas supply configured to control flow rate of gases supplied to the gas inlets to selectively control the flow of gases over the edge zone, the middle zone, and the center zone of a semiconductor substrate; and
a gas exhaust system configured to exhaust gases from the process chamber.
2. A wafer processing system as defined in claim 1 , wherein the gas supply is configured to individually control flow rate and concentration of gases supplied to each of the plurality of gas inlets.
3. A wafer processing system as defined in claim 1 , wherein the gas exhaust system is configured to control the flow rates of gases being exhausted through a plurality of exhaust ports to selectively control the flow of gases over the edge zone, the middle zone, and the center zone of a semiconductor substrate.
4. A wafer processing system as defined in claim 1 , further comprising a second set of gas inlets positioned over the substrate holder.
5. A wafer processing system as defined in claim 1 , wherein the processing chamber includes an upper wall, the upper wall defining a recessed portion within the processing chamber for reducing a boundary layer of a gas flowing through the chamber.
6. A wafer processing system as defined in claim 1 , further comprising a plurality of temperature measurement devices for monitoring the temperature of a semiconductor substrate contained in the chamber, the temperature measurement devices comprising coaxial cables for also delivering gases to the chamber.
7. A wafer processing system as defined in claim 6 , wherein the temperature measurement devices comprise pyrometers.
8. A wafer processing system as defined in claim 1 , wherein the heating device comprises a plurality of resistive heaters.
9. A wafer processing system as defined in claim 1 , wherein the longitudinal section of the gas inlets are positioned in communication with the heating device for preheating a gas flowing through the gas inlets prior to contacting a semiconductor substrate.
10. A wafer processing system as defined in claim 1 , further comprising a wafer rotation device for rotating the substrate holder.
11. A wafer processing system as defined in claim 1 , wherein the processing chamber is configured to receive two semiconductor substrates in a side-by-side relationship.
12. A wafer processing system as defined in claim 1 , wherein the processing chamber comprises a hot wall process cavity in which at least a top wall and a bottom wall of the process cavity are made from materials that generally have the same heating characteristics as the semiconductor substrate being heated.
13. A wafer processing system comprising:
a processing chamber containing a substrate holder for receiving a semiconductor substrate, the substrate holder being rotatable;
a heating device in communication with the processing chamber;
a plurality of gas inlets for flowing gas into the processing chamber over the surface of a semiconductor substrate, each of the gas inlets including a longitudinal section and the gas inlets having a common lateral section that includes a common plenum, wherein gases flow upwards or downwards through the longitudinal section and are then plenumized by the common plenum as the lateral section directs the gases over the surface of a semiconductor substrate; and
a gas exhaust system configured to exhaust gases from the process chamber.
14. A wafer processing system as defined in claim 13 , wherein common plenum is formed by a gas inject support ring.
15. A wafer processing system as defined in claim 14 , wherein the gas inject support ring is arc-shaped.
16. A wafer processing system as defined in claim 13 , wherein the longitudinal section of the gas inlets are positioned in communication with the heating device for preheating a gas flowing through the gas inlets prior to contacting a semiconductor substrate.
17. A wafer processing system as defined in claim 16 , wherein the longitudinal sections of the gas inlets are made from a quartz.
18. A wafer processing system as defined in claim 16 , wherein the longitudinal sections of the gas inlets are made from a silicon carbide.
19. A wafer processing system as defined in claim 13 , wherein the system includes at least five gas inlets.
20. A wafer processing system as defined in claim 13 , wherein the gas exhaust system includes a pump for pumping exhaust gases from the process chamber.
21. A wafer processing system as defined in claim 13 , further comprising a gas supply configured to individually control flow rate and concentration of gases supplied to each of the plurality of gas inlets to selectively control the flow of gases over an edge zone, a middle zone, and a center zone of a semiconductor substrate contained within the chamber.
22. A wafer processing system as defined in claim 13 , wherein the lateral section of each of the plurality of gas inlets extend from the bottom of the processing chamber.
23. A wafer processing system as defined in claim 13 , wherein the lateral section of each of the plurality of gas inlets extend from the top of the processing chamber.