Methods and apparatus for minimizing substrate backside damage
Embodiments of the present disclosure generally relate to apparatus and methods for reducing substrate backside damage during semiconductor device processing. In one implementation, a method of chucking a substrate in a substrate process chamber includes exposing the substrate to a plasma preheat treatment prior to applying a chucking voltage to a substrate support. In one implementation, a substrate support is provided and includes a body having an electrode and thermal control device disposed therein. A plurality of substrate supporting features are formed on an upper surface of the body, each of the substrate supporting features having a substrate supporting surface and a rounded edge.
1. A method of chucking a substrate in a substrate process chamber, comprising:
placing a substrate on a substrate support within a process volume, the substrate comprising:
a body formed of a material comprising a grain size between about 1 μm and about 4 μm; and
a plurality of substrate supporting features formed on a substrate supporting region of the substrate support, the plurality of substrate supporting features comprising between about 75 and about 100 substrate support features, each of the substrate supporting features having a substrate supporting surface and a rounded edge, wherein a ratio of a distance between adjacent substrate supporting features and a diameter of the substrate supporting region is between about 0.01 and about 0.2, and wherein each of the plurality of substrate supporting features have a surface roughness between about 2 Ra and about 3 Ra;
raising the substrate to a distance between about 0.5 mm and about 10 mm from an upper surface of the substrate support;
exposing the substrate to a preheat treatment, the preheat treatment comprising;
flowing one or more inert process gases into the process volume, the inert process gases comprises one or more of helium, argon, and nitrogen, the one or more process gases flowed into the process volume at a flow rate between about 500 sccm and about 5000 sccm;
generating a plasma from the one or more inert process gases and exposing the substrate to the plasma for a period between 10 seconds and about 200 seconds;
maintaining the process volume at a pressure between about 1 Torr and about 20 Torr;
lowering the substrate onto the upper surface of the substrate support while pumping down the process volume; and
applying a chucking voltage to the substrate support after exposing the substrate to the preheat treatment.
2. The method of claim 1 , wherein a variable chucking voltage is applied to the substrate support.
3. The method of claim 2 , wherein the chucking voltage is increased from a first chucking voltage to a second chucking voltage.
4. The method of claim 3 , wherein the rate of voltage increase is between about 100 V/s and about 1000 V/s.
5. The method of claim 1 , wherein a constant chucking voltage is applied to the substrate support.
6. The method of claim 5 , wherein the chucking voltage is between about 500 V and about 1000 V.
7. The method of claim 1 , wherein the preheat treatment further comprises:
heating the process volume to a temperature between about 500° C. and about 650° C. while the substrate is in a raised position.
8. The method of claim 1 , wherein the preheat treatment further comprises:
heating the process volume to a temperature between about 500° C. and about 650° C. while the substrate is in a lowered position.
9. The method of claim 1 , wherein the process volume is maintained at a pressure between about 1 Torr and about 10 Torr.
10. A method of chucking a substrate in a substrate process chamber, comprising:
placing a substrate on a substrate support, the substrate support comprising:
a body formed of a material comprising a grain size between about 1 μm and about 4 μm;
an electrode disposed within the body;
a temperature control device disposed within the body; and
a plurality of substrate supporting features formed on a substrate supporting region of the substrate support, the plurality of substrate supporting features comprising between about 75 and about 100 substrate support features, each of the substrate supporting features having a substrate supporting surface and a rounded edge, wherein a ratio of a distance between adjacent substrate supporting features and a diameter of the substrate supporting region is between about 0.01 and about 0.2, and wherein each of the plurality of substrate supporting features have a surface roughness between about 2 Ra and about 3 Ra;
raising the substrate to a distance between about 0.5 mm and about 10 mm from an upper surface of the substrate support;
exposing the substrate to a preheat treatment, the preheat treatment comprising:
flowing one or more inert gases into a process volume, the inert gases selected from the group consisting of helium, argon, and nitrogen, the inert gases flowed at a flow rate between about 1000 sccm and about 3000 sccm;
generating a plasma from the inert gases;
maintaining the plasma in the process volume for a residence time between about 10 seconds and about 200 seconds; and
lowering the substrate onto the upper surface of the substrate support while pumping down the process volume; and
applying a chucking voltage to the substrate support.