Backside gas leakby for bevel deposition reduction
Exemplary substrate support assemblies include an electrostatic chuck body defining a substrate platform. The substrate platform may be characterized by an upper surface. The platform may define a purge aperture. The platform may include a plurality of mesas that are disposed in an inner region of the upper surface. Each of the mesas may protrude upward from the upper surface. The platform may include a sealing band that extends upward from the upper surface in a circumferential pattern and partially encircles the inner region of the upper surface. Top surfaces of the mesas and sealing band may form a support surface for a substrate. The sealing band may define a number of gaps. The assemblies may include a support stem coupled with the electrostatic chuck body, a heater embedded within the electrostatic chuck body, and a backside gas source that is coupled with the purge aperture of the support surface.
1. A substrate support assembly, comprising:
an electrostatic chuck body defining a substrate platform, wherein:
the substrate platform is characterized by an upper surface, the substrate platform defining a purge aperture; and
the substrate platform comprises:
a plurality of mesas that are disposed in an inner region of the upper surface, wherein each of the plurality of mesas protrudes upward from the upper surface; and
a sealing band that extends upward from the upper surface in a circumferential pattern and partially encircles the inner region of the upper surface, wherein:
top surfaces of the plurality of mesas and the sealing band form a support surface for a substrate;
the sealing band defines a number of gaps;
the sealing band is characterized by a plurality of protruding segments that define a support seat for an outer periphery of a substrate, wherein adjacent pairs of the plurality of protruding segments are separated by a respective one of the number of gaps; and
a size of each of the plurality of segments and a size of each of the number of gaps are substantially equal;
a support stem coupled with the electrostatic chuck body;
a heater embedded within the electrostatic chuck body; and
a backside gas source that is coupled with the purge aperture of the support surface.
2. The substrate support assembly of claim 1 , wherein:
the top surfaces of the plurality of mesas and the sealing band are the same height.
3. The substrate support assembly of claim 1 , wherein:
the gaps are provided at regular angular intervals about the sealing band.
4. The substrate support assembly of claim 1 , wherein:
the support stem defines a fluid lumen that extends between and couples the backside gas source and the aperture.
5. The substrate support assembly of claim 1 , wherein:
the plurality of mesas are uniformly arranged about the inner region of the upper surface.
6. The substrate support assembly of claim 1 , wherein:
the sealing band is positioned on the substrate platform so as to define a support seat for an outer periphery of a substrate; and
a portion of the sealing band and a portion of each gap extends radially outward from an outermost edge of the support seat.
7. The substrate support assembly of claim 1 , wherein:
the sealing band is characterized by a generally circular shape that is interrupted by the number of gaps.
8. The substrate support assembly of claim 1 , wherein:
the backside gas source delivers a reactive purge gas.
9. The substrate support assembly of claim 8 , wherein:
the reactive purge gas comprises O 2 .
10. The substrate support assembly of claim 1 , wherein:
a peripheral edge of the sealing band and a portion of each of the number of gaps extend radially outward of a peripheral edge of a substrate seated on the sealing band.
11. A substrate support assembly, comprising:
electrostatic chuck body defining a substrate platform, wherein:
the substrate platform is characterized by an upper surface, the substrate platform defining a single purge aperture; and
the substrate platform comprises:
a plurality of mesas that are disposed in an inner region of the upper surface, wherein each of the plurality of mesas protrudes upward from the upper surface; and
a sealing band that extends upward from the upper surface in a circumferential pattern and partially encircles the inner region of the upper surface, wherein:
the sealing band is characterized by a plurality of protruding segments that define a support seat for an outer periphery of a substrate;
adjacent pairs of the plurality of protruding segments are separated by one of a plurality of gaps; and
a size of each of the plurality of segments and a size of each of the plurality of gaps are substantially equal;
a support stem coupled with the electrostatic chuck body; and
a backside gas source that is coupled with the purge aperture of the support surface.
12. The substrate support assembly of claim 11 , wherein:
the gaps are provided at regular angular intervals about the sealing band.
13. The substrate support assembly of claim 11 , wherein:
the support stem defines a fluid lumen that extends between and couples the backside gas source and the aperture.
14. The substrate support assembly of claim 11 , wherein:
the plurality of mesas are uniformly arranged about the inner region of the upper surface.
15. The substrate support assembly of claim 11 , wherein:
the backside gas source delivers a reactive purge gas.
16. The substrate support assembly of claim 11 , wherein:
a peripheral edge of the sealing band and a portion of each of the plurality of gaps extend radially outward of a peripheral edge of a substrate seated on the sealing band.
17. A method of processing a semiconductor substrate, comprising:
clamping a semiconductor substrate to a support surface of a substrate platform using a chucking voltage, wherein:
the substrate platform is characterized by an upper surface and defines a single purge aperture; and
the substrate platform comprises:
a plurality of mesas that are disposed in an inner region of the upper surface, wherein each of the plurality of mesas protrudes upward from the upper surface; and
a sealing band that extends upward from the upper surface in a circumferential pattern and partially encircles the inner region of the upper surface, wherein:
the support surface is formed from top surfaces of the plurality of mesas and the sealing band;
the sealing band defines a number of gaps separating a number of protruding segments; and
a size of each of the number of protruding segments and a size of each of the number of gaps are substantially equal; and
flowing a reactive purge gas to an underside of the semiconductor substrate and through the number of gaps.
18. The method of processing a semiconductor substrate of claim 17 , wherein:
the reactive purge gas comprises 02.
19. The method of processing a semiconductor substrate of claim 17 , wherein:
at least a portion of each gap and each protruding segment of the sealing band extends outward beyond an outer periphery of the semiconductor substrate.
20. The method of processing a semiconductor substrate of claim 17 , wherein:
a peripheral edge of the sealing band and a portion of each of the number of gaps extend radially outward of a peripheral edge of the semiconductor substrate.