High temperature substrate heater for use in high and ultra-high vacuum systems
A braze-free substrate heating device including a heater block body, a heater block lid, and a heating element. The heating element sits inside the heater block body. The heater block lid is on the heating element, such that the heating element is sandwiched between the heater block lid and the floor of the heater block body. The heating element is held in place by compressing the heater block lid into the heater block body and attaching the heater block lid to the top of the heater block body so that the heating element is fully supported over its surface area, and can maintain uniform thermal contact with the heater block lid and heater block body over its entire surface area.
1. A braze-free device for heating a substrate, the braze-free device comprising:
a heater block body,
a heater block lid on the heater block body; and
a heating element between the heater block lid and the heater block body;
the heating element being compressed between the heater block body and the heater block lid along a first direction between the heater block lid and the heater block body to deform the heating element along the first direction,
the heating element being in continuous physical and thermal contact with the heater block lid and the heater block body without including a braze alloy,
wherein the heating element comprises a resistive heating wire having an outer protective sheath, and a compressed outer diameter of the resistive heating wire in the first direction is about 2.5% to about 20% of an uncompressed outer diameter of the resistive heating wire.
2. The braze-free device of claim 1 , wherein the first direction is a vertical direction, and the heating element is in substantially continuous surface contact with an upper inside surface of the heater block body and a lower inside surface of the heater block lid.
3. The braze-free device of claim 1 , wherein the first direction is a vertical direction, and the resistive heating wire is coiled in a plane.
4. The braze-free device of claim 1 , wherein the first direction is a radial direction, and the heating element is in substantially continuous surface contact with a convex inside surface of the heater block body and a concave inside surface of the heater block lid.
5. The braze-free device of claim 1 , wherein the first direction is a radial direction, and the resistive heating wire is coiled in the shape of a cylinder.
6. The braze-free device of claim 1 , wherein the compressed outer diameter of the resistive heating wire in the first direction is about 5% to about 7% of the uncompressed outer diameter of the resistive heating wire.
7. A braze-free device for heating a substrate, the braze-free device comprising:
a heater block body,
a heater block lid on the heater block body; and
a heating element between the heater block lid and the heater block body; the the heating element comprising a resistive heating wire having an outer protective sheath and being compressed between the heater block body and the heater block lid along a first direction between the heater block lid and the heater block body to deform the heating element along the first direction,
the heating element being in continuous physical and thermal contact with the heater block lid and the heater block body without including a braze alloy,
wherein the outer protective sheath, the heater block body, and the heater block lid are each made of a high temperature metal or alloy having a coefficient of thermal expansion, the coefficients varying by about 0% to about 10%.
8. The braze-free device of claim 7 , wherein the coefficients are substantially identical.
9. The braze-free device of claim 7 , wherein the high temperature metal or alloy comprises molybdenum (Mo), chromium (Cr), nickel (Ni), tungsten (W), tantalum (Ta), titanium (Ti), cobalt (Co), iron (Fe), niobium (Nb), or a mixture thereof.
10. The braze-free device of claim 1 , wherein the heater block body or the heater block lid includes an inner spacer to fill the lateral space around the lateral perimeter of the heating element.
11. The braze-free device of claim 1 , wherein the heating element is further compressed along a second direction, the second direction being perpendicular to the first direction.
12. A method of constructing a substrate heating device without brazing, the method comprising:
coiling a resistive heating wire to form a heating element, the resistive heating wire having an outer protective sheath;
placing the heating element between a heater block body and a heater block lid;
compressing the heating element between the heater block body and the heater block lid along a first direction between the heater block body and the heater block lid to deform the heating element along the first direction;
forming substantially continuous physical and thermal contacts between the heating element and the heater block lid and the heating element and the heater block body without including a braze alloy; and
attaching the heater block lid to the heater block body,
wherein compressing the heating element between the heater block body and the heater block lid compresses an outer diameter of the resistive heating wire in the first direction by about 2.5% to about 20%.
13. The method of claim 12 , wherein the resistive heating wire is coiled in a plane, the first direction is a vertical direction, and the contacts are formed with an upper inside surface of the heater block body and a lower inside surface of the heater block lid.
14. The method of claim 12 , wherein the resistive heating wire is coiled around the heater block body, the first direction is a radial direction, and the contacts are formed with a convex inside surface of the heater block body and a concave inside surface of the heater block lid.
15. The method of claim 12 , wherein compressing the heating element between the heater block body and the heater block lid compresses the outer diameter of the resistive heating wire in the first direction by about 5% to about 7%.
16. The method of claim 12 , wherein the outer protective sheath, the heater block body, and the heater block lid are each made of a high temperature metal or alloy having a coefficient of thermal expansion, the coefficients varying by about 0% to about 10%.
17. The method of claim 12 , wherein the heater block body or the heater block lid includes an inner spacer to fill the lateral space around the lateral perimeter of the heating element.
18. The method of claim 12 , wherein the attaching the heater block lid to the heater block body comprises fusion welding the heater block lid to the heater block body under compression.
19. The braze-free device of claim 1 , wherein the heater block body, the heater block lid, and the heating element together form a heater block, and the heater block has the shape of a plate, a cup, a solid or open cylinder, or a truncated hollow cone.