Composite substrate for layered heaters
A method of forming a heater assembly for use in semiconductor processing includes thermally securing a heater substrate to an application substrate; and applying a layered heater to the heater substrate after the heater substrate is secured to the application substrate. The application of the layered heater includes applying a first dielectric layer onto the heater substrate, applying a resistive heating layer onto the first dielectric layer, and applying a second dielectric layer onto the resistive heating layer. The heater substrate defines a material having a coefficient of thermal expansion that is matched to a coefficient of thermal expansion of at least one of the first dielectric layer and a coefficient of thermal expansion of the resistive heating layer.
1. A method of forming a heater assembly for use in semiconductor processing comprising the following steps in sequence:
thermally securing a heater substrate to an application substrate using a joining process selected from the group consisting of brazing, welding, soldering, diffusion bonding, epoxying, and vulcanizing;
applying a layered heater to the heater substrate after the heater substrate is secured to the application substrate, the application of the layered heater comprising:
applying a first dielectric layer onto the heater substrate;
applying a resistive heating layer onto the first dielectric layer; and
applying a second dielectric layer onto the resistive heating layer,
wherein the heater substrate defines a material having a coefficient of thermal expansion that is matched to a coefficient of thermal expansion of at least one of the first dielectric layer and a coefficient of thermal expansion of the resistive heating layer.
2. The method according to claim 1 , wherein the heater substrate is brazed to the application substrate.
3. The method according to claim 2 , wherein a silver brazing material is used.
4. The method according to claim 1 , wherein each of the layers of the layered heater are applied by a thermal spray process.
5. The method according to claim 4 , wherein a circuit pattern is formed in the resistive heating layer by a laser removal process.
6. The method according to claim 1 , wherein the first dielectric layer is an alumina material, the heater substrate is a molybdenum material, and the application substrate is an austenitic stainless steel material.
7. The method according to claim 1 further comprising applying a bond coat layer to the heater substrate prior to applying the first dielectric layer.
8. The method according to claim 1 further comprising applying a topcoat layer over the second dielectric layer and subsequently removing portions of the topcoat with a process to achieve a predetermined surface flatness.
9. A method of forming a heater assembly for use in semiconductor processing comprising the following steps in sequence:
brazing a heater substrate to an application substrate;
applying a layered heater to the heater substrate after the heater substrate is secured to the application substrate, the application of the layered heater comprising:
applying a bond coat layer by a thermal spray process onto the heater substrate;
applying a first dielectric layer by a thermal spray process onto the bond coat layer;
applying a resistive heating layer by a thermal spray process onto the first dielectric layer; and
applying a second dielectric layer by a thermal spray process onto the resistive heating layer,
wherein the heater substrate defines a material having a coefficient of thermal expansion that is matched to a coefficient of thermal expansion of at least one of the first dielectric layer and a coefficient of thermal expansion of the resistive heating layer.
10. The method according to claim 9 , wherein a silver brazing material is used.
11. The method according to claim 9 , wherein a circuit pattern is formed in the resistive heating layer by a laser removal process.
12. The method according to claim 9 , wherein the first dielectric layer is an alumina material, the heater substrate is a molybdenum material, and the application substrate is an austenitic stainless steel material.