In-situ epi growth rate control of crystal thickness micro-balancing sensor
A method and apparatus for processing semiconductor substrates is described herein. The apparatus includes one or more growth monitors disposed within an exhaust system of a deposition chamber. The growth monitors are quartz crystal film thickness monitors and are configured to measure the film thickness grown on the growth monitors while a substrate is being processed within the deposition chamber. The growth monitors are connected to a controller, which adjusts the heating apparatus and gas flow apparatus settings during the processing operations. Measurements from the growth monitors as well as other sensors within the deposition chamber are used to adjust processing chamber models of the deposition chamber as substrates are processed therein.
1. An exhaust passage body applicable for semiconductor substrate processing, comprising:
a first exhaust plenum;
a first exhaust entry opening formed through a first end of the exhaust passage body and fluidly connected to the first exhaust plenum;
a first plurality of fins disposed adjacent to the first exhaust entry opening within the first exhaust plenum;
a first exhaust exit opening formed through a second end of the exhaust passage body and fluidly connected to the first exhaust plenum;
a first baffle plate disposed adjacent to the first exhaust exit opening and configured to narrow a first width of the first exhaust plenum; and
at least one growth monitor disposed downstream of the first baffle plate and configured to measure a thickness of a material deposited on the at least one growth monitor.
2. The exhaust passage body of claim 1 , wherein the at least one growth monitor is a quartz crystal film thickness monitor.
3. The exhaust passage body claim 1 , wherein the first baffle plate is oriented to narrow the first exhaust plenum as the first exhaust plenum extends towards the first exhaust exit opening.
4. The exhaust passage body of claim 3 , further comprising:
a second exhaust plenum;
a second exhaust entry opening formed through the first end of the exhaust passage body and fluidly connected to the second exhaust plenum;
a second plurality of fins disposed adjacent to the second exhaust entry opening within the second exhaust plenum;
a second exhaust exit opening formed through the second end of the exhaust passage body and fluidly connected to the second exhaust plenum; and
a second baffle plate disposed adjacent to the second exhaust exit opening and configured to narrow a second width of the second exhaust plenum.
5. The exhaust passage body of claim 1 , wherein the first exhaust entry opening has an entry width and the first exhaust exit opening has an exit width, a ratio of the entry width to the exit width being about 2:1 to about 20:1.
6. The exhaust passage body of claim 5 , wherein the entry width of the first exhaust entry opening is about 10 mm to about 210 mm.
7. The exhaust passage body of claim 1 , wherein the first plurality of fins includes at least four fins.
8. The exhaust passage body of claim 7 , wherein each of the first plurality of fins are oriented parallel to one another.
9. An exhaust system applicable for semiconductor substrate processing, comprising:
an exhaust passage body comprising:
an exhaust plenum;
an exhaust entry opening formed through a first end of the exhaust passage body and having an entry width;
a plurality of fins disposed adjacent to the exhaust entry opening within the exhaust plenum;
an exhaust exit opening formed through a second end of the exhaust passage body and fluidly connected to the exhaust plenum;
at least one baffle plate disposed adjacent to the exhaust exit opening and configured to narrow a width of the exhaust plenum to an exit width less than the entry width; and
at least one growth monitor disposed downstream of the at least one baffle plate and configured to measure a thickness of a material deposited on the at least one growth monitor; and
an exhaust collector coupled to the exhaust passage body at the exhaust exit opening.
10. The exhaust system of claim 9 , wherein the at least one growth monitor is a quartz crystal film thickness monitor.
11. The exhaust system of claim 10 , wherein the quartz crystal film thickness monitor comprises:
a sensor holder;
a quartz crystal disposed within the sensor holder;
a back contact contacting a first side of the quartz crystal;
a front contact contacting a second side of the quartz crystal;
a protective coating disposed on the second side of the quartz crystal; and
a sensor opening disposed through the sensor holder and exposing the protective coating to gases flowing through the exhaust plenum.
12. The exhaust system of claim 11 , wherein at least one of the back contact and the front contact comprise a gold material.
13. The exhaust system of claim 11 , wherein the protective coating is alumina or silicon dioxide.
14. The exhaust system of claim 9 , wherein the plurality of fins are a material with a thermal conductivity of above about 100 W/m·° K.
15. The exhaust system of claim 14 , wherein the material contains silicon carbide.
16. The exhaust system of claim 9 , wherein the at least one growth monitor is disposed within the exhaust collector adjacent to the exhaust exit opening.
17. The exhaust system of claim 9 , wherein the at least one baffle plate is a curved plate.
18. A process system applicable for semiconductor substrate processing, comprising:
a chamber body forming a process volume;
a substrate support disposed within the process volume of the chamber body;
an upper window disposed above the substrate support;
a lower window disposed below the substrate support, wherein each of the upper window and the lower window further define the process volume;
an injector disposed through one side of the chamber body and configured to introduce a process gas to the process volume;
an exhaust system disposed through a second side of the chamber body opposite the injector and comprising:
an exhaust passage body;
an exhaust plenum disposed through the exhaust passage body;
an exhaust entry opening formed through a first end of the exhaust passage body, the exhaust entry opening configured to fluidly connect the exhaust plenum and the process volume;
a plurality of fins disposed within the exhaust plenum;
an exhaust exit opening formed through a second end of the exhaust passage body and fluidly connected to the exhaust plenum;
at least one baffle plate disposed downstream of the plurality of fins and configured to narrow a width of the exhaust plenum to an exit width less than an entry width; and
at least one growth monitor disposed downstream of the at least one baffle plate and configured to measure a thickness of a material deposited on the at least one growth monitor.
19. The process system of claim 18 , wherein the at least one growth monitor is in communication with a controller configured to determine growth rates on the at least one growth monitor and adjust at least one of process gas flow rates, heating energy levels, or exhaust flow rates.
20. The process system of claim 19 , wherein the controller compares measured growth rates on the at least one growth monitor, a chamber thermal model, a chamber flow model, and previous monitor measurements to determine how to adjust at least one of the process gas flow rates, the heating energy levels, or the exhaust flow rates.