CVD Reactor Single Substrate Carrier and Rotating Tube for Stable Rotation
A self-centering substrate carrier system for a chemical vapor deposition reactor includes a substrate carrier chosen to at least partially support a wafer for CVD processing and that comprises a beveled surface. A rotating tube comprising a beveled surface that matches the beveled surface of the substrate carrier, where a shape and dimensions of a cross section of the substrate carrier are chosen such that a center of mass of the substrate carrier is positioned a distance that is below a plane of contact defined by where a rim of substrate carrier contacts a rim of the rotating tube.
1 . A self-centering substrate carrier system for a chemical vapor deposition (CVD) reactor, the substrate carrier system comprising:
a) a substrate carrier comprising a beveled surface, the substrate carrier being configured to at least partially support a wafer for CVD processing; and
b) a rotating tube comprising a beveled surface that matches the beveled surface of the substrate carrier, a shape and dimensions of a cross section of the substrate carrier being chosen such that a center of mass of the substrate carrier is positioned below a plane of contact defined by where a rim of substrate carrier contacts a rim of the rotating tube.
2 . The self-centering substrate carrier system of claim 1 wherein the shape and dimensions of the cross section of the substrate carrier are chosen such that the center of mass of the substrate carrier is positioned such that the distance is less than 1.0 mm from the plane of contact between the substrate carrier and rotating tube.
3 . The self-centering substrate carrier system of claim 1 wherein the shape and dimensions of the cross section of the substrate carrier are chosen such that the center of mass of the substrate carrier is positioned such that the distance is less than 0.5 mm from the plane of contact between the substrate carrier and rotating tube.
4 . The self-centering substrate carrier system of claim 1 wherein the shape and dimensions of the cross section of the substrate carrier are chosen such that the center of mass of the substrate carrier is positioned at the plane of contact between the substrate carrier and rotating tube.
5 . The self-centering substrate carrier system of claim 1 wherein the shape and dimensions of the cross section of the substrate carrier is chosen to minimize a destabilizing moment produced during rotation.
6 . The self-centering substrate carrier system of claim 1 wherein the shape and dimensions of the substrate carrier are chosen so that there is a coincident alignment of a central axis of the substrate carrier and a rotation axis of the rotating tube during processing at a desired process temperature
7 . The self-centering substrate carrier system of claim 6 wherein the coincident alignment of the central axis of the substrate carrier and the rotation axis of the rotating tube during processing at the desired process temperature establishes an axial-symmetrical temperature profile across the wafer.
8 . The self-centering substrate carrier system of claim 1 wherein the substrate carrier supports an entire bottom surface of the wafer.
9 . The self-centering substrate carrier system of claim 1 wherein the substrate carrier supports the wafer at a perimeter of the wafer, leaving a portion of both a top and a bottom surface of the wafer exposed.
10 . The self-centering substrate carrier system of claim 1 wherein a shape and dimensions of the substrate carrier are chosen so that a rotation eccentricity of the wafer is substantially zero at the desired process temperature.
11 . The self-centering substrate carrier system of claim 1 wherein the beveled surface of the substrate carrier and the beveled surface of the rotating tube are dimensioned to define a gap.
12 . The self-centering substrate carrier system of claim 11 wherein a width of the gap approaches zero at the desired process temperature.
13 . The self-centering substrate carrier system of claim 11 wherein a coefficient of thermal expansion of a material forming the substrate carrier and a coefficient of thermal expansion of a material forming the rotating tube are chosen so that a width of the gap reduces during heating due to thermal expansion.
14 . The self-centering substrate carrier system of claim 11 wherein a coefficient of thermal expansion of a material forming the substrate carrier and a coefficient of thermal expansion of a material forming the rotating tube are chosen so that the gap is maintained at processing temperatures.
15 . The self-centering substrate carrier system of claim 11 wherein a width of the gap at room temperature is chosen so that there is space for expansion of the substrate carrier relative to the rotating tube at processing temperatures.
16 . The self-centering substrate carrier system of claim 1 wherein the bevel surface of the substrate carrier and the beveled surface of the rotating tube are parallel to each other.
17 . The self-centering substrate carrier system of claim 1 wherein the bevel surface of the substrate carrier and the beveled surface of the rotating tube are each at angle α relative to a rotation axis such that tan(α)>ƒ, where ƒ is a coefficient of friction between the substrate carrier and rotation tube.
18 . The self-centering substrate carrier system of claim 1 wherein the cross section of the substrate carrier is formed in a substantially rectangular shape overall.
19 . The self-centering substrate carrier system of claim 1 wherein the rotating tube comprises vented sidewalls.
20 . The self-centering substrate carrier system of claim 1 wherein the vented sidewalls are configured to equalize pressure in the regions above and below the substrate carrier.
21 . A method of manufacturing a self-centering substrate carrier system for a chemical vapor deposition (CVD) reactor, the method comprising:
a) forming a rotating tube comprising a beveled surface and a rim; and
b) forming a substrate carrier that at least partially supports a wafer for CVD processing and that has a beveled surface and a rim, a cross section of the substrate carrier being formed in a shape and with dimensions that result in a center of mass of the substrate carrier being positioned a distance that is below a plane of contact defined by where the rim of substrate carrier contacts the rim of the rotating tube.