Physical vapor deposition with heat diffuser
A physical vapor deposition apparatus includes a vacuum chamber having side walls, a cathode inside the vacuum chamber, wherein the cathode is configured to include a sputtering target, a radio frequency power supply configured to apply power to the cathode, an anode inside and electrically connected to the side walls of the vacuum chamber, and a chuck inside and electrically isolated from the side walls of the vacuum chamber, the chuck configured to support a substrate, and a heater to heat the substrate supported on the chuck. The chuck includes a body and a graphite heat diffuser supported on the body and configured to contact the substrate.
1. A physical vapor deposition apparatus comprising:
a vacuum chamber having side walls;
a cathode inside the vacuum chamber, wherein the cathode is configured to include a sputtering target;
a radio frequency power supply configured to apply power to the cathode;
an anode inside and electrically connected to the side walls of the vacuum chamber;
a chuck inside and electrically isolated from the side walls of the vacuum chamber, the chuck configured to support a substrate, the chuck comprising a body formed of a metal alloy and a disk-shaped graphite heat diffuser supported on the body, the disk-shaped graphite heat diffuser having a substantially planar top surface configured to contact the substrate and a parallel bottom surface in contact with an upper surface of the body formed of the metal alloy, and the heater diffuser including a plurality of passages therethrough, the passages being between about 0.0044% and 1% of the surface area of the substantially planar top surface; and
a heater to heat the substrate supported on the chuck, the heater comprising a resistive heater embedded in the body of the chuck to provide heat to the substrate supported by the chuck through at least a flow in the plurality of passages of the heat diffuser that carries heat from the resistive heater to at least a portion of space between the graphite heat diffuser and the substrate such that heat is conducted through the graphite heat diffuser to the substrate.
2. The physical vapor deposition apparatus of claim 1 , wherein each of the passages extends vertically through the heat diffuser.
3. The physical vapor deposition apparatus of claim 1 , wherein each of the passages is between about 100 and 1,000 μm in diameter.
4. The physical vapor deposition apparatus of claim 3 , wherein each of the passages is about 500 μm in diameter.
5. The physical vapor deposition apparatus of claim 1 , wherein the passages have a spacing of about 10 to 15 mm.
6. The physical vapor deposition apparatus of claim 1 , wherein the heat diffuser is between about 1 mm and 5 mm thick.
7. The physical vapor deposition apparatus of claim 6 , wherein the heat diffuser is about 2 mm thick.
8. The physical vapor deposition apparatus of claim 1 , wherein a top surface of the heat diffuser is substantially planar.
9. The physical vapor deposition apparatus of claim 8 , wherein the heat diffuser is configured such that a bottom surface of the substrate is substantially flush with the top surface of the heat diffuser.
10. The physical vapor deposition apparatus of claim 1 , wherein the target comprises a dielectric material.
11. The physical vapor deposition apparatus of claim 10 , wherein the material comprises lead zirconate titinate (“PZT”).
12. The physical vapor deposition apparatus of claim 1 , further comprising an impedance matching network electrically connected to the chuck.
13. A method of physical vapor deposition comprising:
applying a radio frequency signal to a cathode in a physical vapor deposition apparatus, wherein the cathode includes a sputtering target;
supporting a substrate on a chuck, the chuck comprising a body formed of a metal alloy and a disk-shaped graphite heat diffuser supported on the body, the disk-shaped graphite heat diffuser having a substantially planar top surface and a parallel bottom surface in contact with an upper surface of the body formed of the metal alloy;
contacting the substrate to the substantially planar top surface of the disk-shaped graphite heat diffuser located between the chuck and the substrate while heating the substrate, the graphite heat diffuser including a plurality of gas passages therethrough, the passages being between about 0.0044% and 1% of the surface area of the substantially planar top surface;
heating the substrate using a resistive heater embedded in the body of the chuck through the graphite heat diffuser, the substrate being heated by at least a flow in the plurality of passages of the heat diffuser that carries heat from the resistive heater to at least a portion of space between the graphite heat diffuser and the substrate; and
depositing a material from the sputtering target onto the substrate.
14. The method of claim 13 , wherein a temperature across the heated substrate varies by less than 10° C.
15. The method of claim 13 , wherein the radio frequency signal has a radio frequency power having a magnitude of between about 1000 W and 5000 W.
16. The method of claim 13 wherein the radio frequency power is about 3000 W.
17. The method of claim 13 wherein the target comprises a dielectric material.
18. The method of claim 17 wherein the dielectric material comprises lead zirconate titinate (“PZT”).
19. The method of claim 13 , wherein deposited material forms a film on the substrate, the film having a thickness of between about 2000 Å and 10 μm.
20. The method of claim 19 , wherein the thickness is between about 2 μm and 4 μm.