THERMOCOUPLE

• US 20080289574A1
• Filed: 05/15/2008
• Published: 11/27/2008
• Est. Priority Date: 05/24/2007
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM America Incorporated (ASM International NV)
• Inventors: Jacobs, Loren, Halpin, Mike
• Granted Patent: US 7,874,726 B2
• Time in Patent Office: Days
• US Class Current: 118/708
• CPC Class Codes: G01K 1/08 Protective devices, e.g. casings
• CPC Class Codes: G01K 7/02 using thermoelectric elements, e.g. thermocouples
• CPC Class Codes: G01K 7/04 the object to be measured not forming one of the thermoelectric materials

Abstract

A thermocouple having a support tube configured to receive a pair of wires of dissimilar metals. The pair of wires of the thermocouple connected at a junction adjacent to one end of the support tube. The thermocouple further including a cap attached to the opposing end of the support tube, wherein the cap receives the free ends of the pair of wires. The cap allowing the pair of wires to translate freely therethrough to accommodate the difference in thermal expansion and contraction of the pair of wires relative to the thermal expansion and contraction of the support tube.

Claims

1. A thermocouple comprising:

a support tube having a first distal end, a second distal end, and a longitudinal axis, said support tube including a pair of bores extending between said first distal end and said second distal end;

a sheath disposed about at least a portion of said support tube;

a first wire disposed within one of said bores;

a second wire disposed within the other of said bores, said second wire formed of a different metal than said first wire;

a junction formed between an end of said first wire and an end of said second wire, wherein said junction is located adjacent to said first distal end of said support tube; and

a cap operatively attached to said second distal end of said support tube, said cap having a first bore to receive said second distal end of said support tube and a second bore through which said first and second wires extend, said cap further including a web formed between said first and second bore, said web including a first aperture for receiving said first wire and a second aperture for receiving said second wire, said apertures being sized to allow said first and second wires to slide freely therethrough in response to thermal expansion or contraction of said first and second wires.

2. The thermocouple of claim 1 further comprising a loop formed of a portion of said first and second wires extending from said cap.

3. The thermocouple of claim 2, wherein a band is applied around a portion of said loop to maintain a predetermined radius of curvature of the loop.

4. The thermocouple of claim 2, wherein said loop has a radius of curvature of about 5 mm.

5. The thermocouple of claim 2, wherein said loop has a radius of about 12 mm.

6. The thermocouple of claim 2, wherein said loop has a radius of curvature of between about 2 mm and about 25 mm.

7. The thermocouple of claim 2, wherein said loop has a radius of curvature of between about 2 mm and 12 mm.

8. The thermocouple of claim 2, wherein said loop has a radius of curvature that increases as said first and second wires thermally expand and decreases as said first and second wires thermally contract.

9. The thermocouple of claim 1, wherein said cap is substantially fixed relative to said support tube.

10. The thermocouple of claim 1, wherein said first and second apertures formed through said web have a diameter, said diameter being larger than a diameter of each of said first and second wires passing therethrough.

11. A thermocouple comprising:

a support tube having a pair of bores extending therethrough;

a pair of wires formed of dissimilar metals, each of said wires being disposed within a different one of said bores of said support tube; and

a cap having a pair of apertures formed therethrough, wherein each of said apertures receives one of said pair of wires, said cap being fixedly attached to said support tube, and said apertures being sized to allow said wires to slide freely through said pair of apertures during thermal expansion or contraction of said wires while maintaining said pair of wires in a spaced-apart relationship therebetween.

12. The thermocouple of claim 11, wherein said pair of apertures formed through said cap are spaced apart, thereby maintaining said pair of wires in a spaced-apart relationship.

13. The thermocouple of claim 11, wherein said pair of wires are exposed as they exit said apertures formed in said cap and a protective tube encases a portion of said exposed pair of wires as said pair of wires exit said pair of apertures formed in said cap.

14. A cap connectable to a support tube of a thermocouple for receiving a pair of wires, said cap comprising:

a body having a first end and a second end;

a first bore extending into said body from said first end, said support tube being receivable in said first bore;

a second bore extending into said body from said second end;

a web separating said first bore and said second bore;

a first aperture formed through said web, one of said wires being receivable in said first aperture;

a second aperture formed through said web, the other of said wires being receivable in said second aperture, and said second aperture spaced apart from said first aperture a distance to maintain said wires in a spaced-apart relationship; and

said apertures being sized to allow said wires to freely translate therethrough when said wires expand or contract as a result of thermal expansion or contraction of said wires.

15. A temperature control system for a chemical vapor deposition reactor for processing a substrate, said temperature control system comprising:

a plurality of temperature sensors located adjacent to said substrate;

a controller that receives temperature data from each of said plurality of temperature sensors;

at least one heating element located adjacent to said substrate for providing radiant energy to said substrate;

said controller selectively adjusting said at least one heating element in response to temperature data provided by at least one of said plurality of temperature sensors; and

at least one of said plurality of temperatures sensors being a thermocouple, said thermocouple comprising;

a pair of wires formed of dissimilar metals;

a support tube having two bores formed therethrough, wherein one of said bores receives one of said wires and the other one of said bores receives the other said wire; and

a cap attached to an end of said support tube, said cap receiving said wires extending from said support tube, wherein said cap maintains said wires in a spaced-apart relationship, and said cap allows said wires to freely thermally expand or contract relative to said support tube while maintaining said wires separated.

16. A thermocouple comprising:

a support tube having a pair of bores formed therethrough, said support tube having a coefficient of thermal expansion; and

a pair of wires formed of dissimilar metals, said wires being disposed within said support tube in a spaced-apart relationship, each of said pair of wires having a coefficient of thermal expansion different than said coefficient of thermal expansion of said support tube, whereby said wires freely thermally expand or contract relative to said support tube as said support tube and said wires are heated or cooled.