Substrate support with electrically floating power supply
Embodiments described herein generally relate to plasma assisted or plasma enhanced processing chambers. More specifically, embodiments herein relate to electrostatic chucking (ESC) substrate supports configured to provide pulsed DC voltage, and methods of applying a pulsed DC voltage, to a substrate during plasma assisted or plasma enhanced semiconductor manufacturing processes.
1. A processing method, comprising:
electrostatically chucking a substrate to a substrate support by applying a first DC power from a first DC power source to a chucking electrode embedded in a dielectric material of the substrate support, wherein
a surface of the substrate support and a surface of the substrate electrostatically chucked thereto define a plenum, and
the substrate support is disposed in a processing volume of a processing chamber;
delivering helium gas to the plenum; and
biasing the substrate by applying a second DC power from a second DC power source to a plurality of conductive pins disposed in the substrate support and extending upwardly from a substrate supporting surface thereof, wherein the plurality of conductive pins are in direct contact with the substrate electrostatically chucked to the substrate support, and wherein the first DC power source is electrically coupled to a reference voltage contact of the second DC power source.
2. The method of claim 1 , wherein applying the second DC power comprises pulsing the second DC power by operating a bias controller disposed between the second DC power source and the plurality of conductive pins.
3. The method of claim 2 , wherein the substrate support is disposed on an electrically conductive support base, and wherein individual ones of the plurality of conductive pins are electrically coupled to the support base.
4. The method of claim 2 , wherein pulsing the second DC power comprises cyclically pulsing the second DC power at a frequency between about 10 Hz and about 100 kHz.
5. The method of claim 4 , wherein a duty cycle of the cyclically pulsed second DC power is between about 10% and about 90%.
6. The method of claim 2 , further comprising forming a plasma in the processing volume.
7. The method of claim 6 , wherein forming the plasma comprises:
flowing a processing gas into the processing volume; and
applying a power to a plasma electrode facing the substrate support.
8. The method of claim 7 , wherein pulsing the second DC power comprises cyclically pulsing the second DC power at a frequency between about 10 Hz and about 100 kHz.
9. The method of claim 8 , wherein a duty cycle of the cyclically pulsed second DC power is between about 10% and about 90%.
10. The method of claim 9 , wherein a potential difference between the chucking electrode and the substrate in contact with the plurality of conductive pins is about constant while cyclically pulsing the second DC power.
11. The method of claim 10 , wherein a chucking force on the substrate is about constant while cyclically pulsing the second DC power.
12. A processing method, comprising:
forming a plasma in a processing volume of a processing chamber by flowing a gas into the processing volume and applying a plasma power to a plasma electrode facing a substrate support;
electrostatically chucking a substrate to a substrate support by applying a first DC power from a first DC power source to a chucking electrode embedded in a dielectric material of the substrate support, wherein
a surface of the substrate support and a surface of the substrate electrostatically chucked thereto define a plenum,
the substrate support is disposed in the processing volume, and
the substrate support is disposed on a support base to form a substrate support assembly;
delivering helium gas to the plenum; and
biasing the substrate by applying a second DC power from a second DC power source to a plurality of conductive pins disposed in the substrate support and extending upwardly from a substrate supporting surface thereof, wherein
the plurality of conductive pins are in direct contact with the substrate electrostatically to the substrate support,
the first DC power source is electrically coupled to a reference voltage contact of the second DC power source, and
the second DC power comprises a pulsed DC power having a frequency between about 10 Hz and about 100 kHz.
13. The method of claim 12 , wherein applying the second DC power comprises cyclically pulsing the second DC power at a duty cycle between about 10% and about 90%.
14. The method of claim 13 , wherein a potential difference between the chucking electrode and the substrate is about constant while applying the second DC power.
15. The method of claim 13 , wherein the support base is electrically conductive and wherein individual ones of the plurality of conductive pins are electrically coupled to the support base.
16. A processing method, comprising:
positioning a substrate on a surface of a substrate support disposed in a processing volume of a processing chamber, the substrate support comprising a chucking electrode embedded in a layer of dielectric material and a plurality of conductive pins individually disposed through the dielectric material to make direct contact with the substrate during processing thereof;
flowing a processing gas into the processing volume;
forming a plasma of the processing gas;
electrostatically chucking the substrate to the substrate support by applying a first DC power from a first DC power source to the chucking electrode, wherein
the first DC power source is electrically coupled between the chucking electrode and a reference voltage contact of a second DC power source,
the second DC power source is electrically coupled to the plurality of conductive pins, and
a surface of the substrate support and a surface of the substrate electrostatically chucked thereto define a plenum;
delivering helium gas to the plenum; and
biasing the substrate by applying a second DC power from the second DC power source to the plurality of conductive pins.
17. The method of claim 16 , wherein biasing the substrate comprises pulsing the second DC power by operating a bias controller disposed between the second DC power source and the plurality of conductive pins.
18. The method of claim 17 , wherein the first DC power source electrically floats on a pulsed DC voltage from the bias controller.
19. The method of claim 3 , wherein
individual ones of the plurality of conductive pins are disposed on the electrically conductive support base,
individual ones of the plurality of conductive pins are disposed through corresponding openings in the chucking electrode, and
individual ones of the plurality of conductive pins are electrically isolated from the chucking electrode by dielectric material of the substrate support disposed there between.