Substrate support having brazed plates and resistance heater

1. A substrate support comprising:

(a) a top plate of metal comprising

(1) a top feedthroughs;

(2) a top surface comprising:

(i) a plurality of outwardly projecting mesas dispersed across a recessed pocket;

(ii) a network of recessed grooves;

(iii) a vacuum port terminating in the recessed grooves and connected to a top feedthrough; and

(iv) a plurality of gas ports connected to another top feedthrough; and

(3) a bottom surface comprising:

(i) a groove;

(ii) a resistance heater in the groove, the resistance heater comprising a first resistive heating element about a peripheral region of the metal plate and a second resistive heating element about a central region of the metal plate, each resistive heating element being in a tube surrounded by an electrical insulator powder; and

(iii) a thermally conductive filler that surrounds the resistance heater and fills in the gap between the resistance heater and the groove;

(b) a middle plate of metal comprising a plurality of middle feedthroughs which are aligned to the top feedthroughs of the top plate, the middle plate joined to the top plate by a first brazed bond layer comprising a metal alloy; and

(c) a bottom plate of metal comprising a plurality of bottom feedthroughs which are aligned to the middle feedthroughs of the middle plate, the bottom plate joined to the middle plate by a second brazed bond layer comprising a metal alloy, and wherein the top, middle and bottom feedthroughs are sealed around their edges.

2. A support according to claim 1 wherein the first or second brazed bond layers comprises a brazing compound comprising at least one of aluminum, copper, indium, lead, magnesium, nickel, tin, silicon and their alloys thereof.

3. A support according to claim 1 wherein the top surface comprises a central portion and a peripheral portion, and the recessed grooves comprise a plurality of spaced apart arms that originate at a circular groove at the central portion which contains the vacuum port and extend radially across the substrate to terminate in semicircular grooves at the peripheral portion.

4. A support according to claim 1 wherein the mesas are substantially cylindrical.

5. A support according to claim 4 comprising from about 10 to about 1000 mesas.

6. A support according to claim 1 further comprising a sealing rim about the mesas.

7. A support according to claim 6 wherein the mesas and sealing rim each have a surface flatness of from about 20 to about 100 microns.

8. A support according to claim 1 wherein the recessed pocket comprises a surface roughness of from about 2 to about 80 microns.

9. A support according to claim 1 wherein a depth of the recessed pocket from a top surface of the mesas is from about 25 to about 250 microns.

10. A support according to claim 1 wherein the first and second resistive heating elements each comprise two concentric loops.

11. A support according to claim 10 wherein each resistive heating element is shaped as a spiral coil.

12. A support according to claim 1 wherein the top metal plate comprises

(a) a recessed pocket comprising a surface roughness of from about 2 to about 80 microns; and

(b) a sealing rim surrounding the recessed pocket, the mesas and the sealing rim each having a surface flatness of from about 20 to about 100 microns.

13. A support according to claim 1 wherein any one of the top, middle or bottom plate of metal comprises stainless steel.