Category Archives: Thermo-slider

High-End Thermal Solutions for Semicon Front-End Processes

In the semiconductor sector, machine-manufacturers at different stages of the wafer manufacturing process are looking for high-performing heating solutions that meet cutting-edge specifications in terms of design, uniformity, repeatability and lifetime but that are also able to withstand very corrosive environments under ultra-high vacuum and with ambient temperatures above 100°C.

THERMOCOAX’s expertise is in responding to strict specifications and in designing tailor-made high-performing thermal solutions from mineral insulated cables.

Our engineering know-how, our prototyping capacity and our knowledge of mineral insulated cables allow us to offer unique solutions to our customers.

We are also able to develop complex mechanical parts that incorporate our heating elements.

Our strength is that we master all these processes internally with a factory certified “Copy exact” dedicated to SEMICON applications for wafer manufacturing processes: high precision machining, welding, soldering, tests and qualifications, control, ….

Over the last few months, THERMOCOAX has developed an innovative, reliable and efficient solution to heat a system inside a vacuum chamber.

The challenge of this project was combining two thermal systems that had to be integrated into the customer’s final system, in an ultra-high vacuum and corrosive environment at high temperature.

The first thermal system that we had to develop was a kind of heating element coiled on a mandrel

The solution was complex because we had to meet critical specifications such as:
• The limitations and dimensional tolerances of the heater
• Critical operating temperature of 800°C
• Achieving a 10% power distribution uniformity – Several heating areas have been designed with different power densities
• Operational guarantee > 5 years, in ultra-high vacuum with a corrosive environment

We designed 6 different concepts and compared these solutions in order to select one.

THERMOCOAX chose a design with EC wound / brazed on a metal support which was mass-produced in line with a specific process.

Progress achieved – results achieved – originality of the chosen solution

This design, which at first glance looks like a heating cartridge, is innovative in its design because it has a fully wound heating element integrated in a mandrel by a process developed by THERMOCOAX.

The expected performances and lifetime results were validated during the qualification phase of the prototypes.

This all-encompassing design by THERMOCOAX targets many areas, with its performance advantages, its low cost design and its long lifetime performance.

The second thermal system is a complex assembly of a 3D design metal part with high temperature heating elements

Problems to solve

Being able to assemble complex metallics with a demanding dimensional specification and an operating temperature that can reach up to 800-900°C.

This temperature is near critical, especially when specifying a lifetime greater than 5 years.

We had to resolve the problem of complex machining.

It was also necessary to take the deformations caused by the machining into account, as well as the deformation from the welding and brazing processes.

The design and manufacturing method was developed entirely by THERMOCOAX to achieve a feasible design suitable for high volume manufacturing and minimizing the risk of non-compliance with dimensional or functional specifications.

We worked on raw material (304L) and evaluated and selected the material that was the most cost / quality / time effective.
For the metallic parts we evaluated: Full mass / forged / foundry material.

The other challenge with these pieces was treating them on the surface so that the highly corrosive liquid in the vacuum chamber would not stick to them.

After much research and testing we identified a substance that has very good anti-wetting properties and could be used for this type of application.

Work has also been done to validate the most suitable deposition process (PVD or CVD).
We finally selected the best deposit solution that operates in up to 600°C.


THERMOCOAX Turbines Solutions Long-life Thermocouples

Thermocoax announces a new thermocouple generation :

  • 24 000 operation hours in heavy duty gas turbine
  • Exceptional resistance to vibration, thermal stress, corrosion…
  • Already demonstrated in air-cooled 446MWatt machine
  • 37 gas turbine  already equipped
  • 18 currently under operation
  • 1.2 Million hours cumulated
  • 699 starts


Technical application of long-life thermocouples

The gas turbine frames market is a challenging business. On the one hand, the frames are more and more high-tech and expensive and on the other hand, the energy producer is driven by low electricity production prices. To make them both compatible, gas turbine frames have to be reliable to minimize operation disruption and to offer longer periods without maintenance. Therefore, providing thermocouples with an increased lifespan decreases the downtime of the turbine, thereby significantly reducing the maintenance costs.

Required Benefits

One of the key aims of the OEM GT is to find high-accuracy thermocouples on the market that are able to perform in harsh environments and work for 24,000 operating hours without failing.

Thermocouples installed in exhaust gas lines are exposed to corrosion, vibration, thermal expansion and much more.

Thermocoax’s Solution: Design a thermocouple that is out of the excitation bandwidth

Based on the capitalized cumulative return of experience in several fields, such as aeronautical, nuclear and oil & gas, THERMOCOAX has developed a vibration absorber that is secured to the thermocouple to avoid premature breaking when the thermocouple is subject to vibrations and thermal expansion. This solution is protected by a patent.

The invention with the patent number 63638FR/CZ/BB – 17 58061 is a vibration absorber that is secured to the thermocouple cable and is made to fit inside the screen/thermowell.

The number and size of the absorbers depend on the gas turbine specification in terms of vibration, acceleration and thermal cycles.

To demonstrate the advantage of this new design and its ability to reach 24,000 operating hours, THERMOCOAX has undertaken simulation and experimental testing:

1.1 Simulation: Comparison between a thermocouple with and without a vibration absorber

Input data:

  • Ø ≈ 3mm Type K thermocouple with 316L SS sheath
  • Length ≈ 500mm insertion length in SS316L thermowell
  • Temperature 870°C
  • Frequency range: 0 to 250Hz, mean value 100Hz
Long-Life TC Standard TC
Resonant Frequency of the TC 174Hz 68 Hz
Stress produced by the Resonant Frequency of the TC 11.1MPa 450MPa
Number of cycles made before Breaking of TC at its Resonant Frequency 9×109 40
Life-span at the Resonant Frequency of the TC 2.1×109 days 10 days

1.2) Field test results: Comparison between a thermocouple with and without a vibration absorber

  • Ø ≈ 3mm Type K thermocouple with 316L SS sheath
  • Length ≈ 300mm insertion length in SS316L thermowell
  • Temperature 900°C
  • Frequency range: 0 to 1000Hz,
Long-Life TC Standard TC
Resonant Frequency of the TC 68Hz 174Hz
Life-span during the Endurance Test Still works after


Stops working before 3000h


The test is still ongoing. We can already say that the field results demonstrate the extraordinary positive impact on the reliability of the gas turbine. This new long-life thermocouple lasts 7 times as long as a standard thermocouple.

For the powerplant operator, the cost saving is at least 150,000 euros in thermocouples for every 20,000 hours of operation because there are no costs incurred from the frame shutting for unexpected maintenance.



For 60 years THERMOCOAX has been a worldwide key player in designing, developing and manufacturing thermocouple temperature sensors for industrial and aircraft gas engines.

With our custom-made Mineral Insulated Cable, we are providing our customers with solutions for:

  • Development applications:
    • R&D programs with institutes
    • Ground, aero & industrial test equipment
  • Production models:
    • Thermocouples in harsh environments with an installed base of over 300,000 thermocouples:
      • Heavy duty gas turbine
      • Stroke engine
      • Steam turbine
    • Thermocouples for helicopter engines with 15,000 units installed
  • Thermocouple characteristics:

Thermocouples are produced with Class 1 custom-made cables with a diameter from 0.25mm up to 6mm.

Single (2 wires) or duplex design (4 wires)
Types K and N are the most used in the industry.

Thermocoax recommends type N thermocouples for a working temperature of between 600°C and 1100°C, which offer a smaller drift compared to type K.

We have several sheath alloys available:

  • Stainless Steel
  • Inconel
  • Haynes
  • Platinum
  • Tantalum



THERMOCOAX Calibration Lab

100% of the mineral insulated cable and finished thermocouples are controlled in the calibration lab.

  • Capabilities

Fixed points

TEMPERATURE -Thermocouple
Calibration purpose Mesurand Measurement range Best calibration uncertainty Measurement principle/Method reference (*) Calibration tools (reference, Equipement) Activities in Lab and/or on site
Thermoelectric couple Temperature                                                                              Electromotive Force Signal Voltage Melting ice point 0,00°C ±0,3°C Method by comparaison at a fixed point / PP200D010 Rev06 Water triple, Sn, Pb, Zn cells Platinum resistance thermometer multimeter                                                  Melting ice point Lab
Water Triple point 0,01°C ±0,3°C
Sn Melting point 231,928°C ±0,5°C
Pb melting point 327,46°C ±0,5°C
Zn melting point 419,46°C ±0,5°C
Sb freezing point 630,62°C ±0,9°C Sb Cells                                              Thermoelectric couple S Type Multimeter                                              Melting ice point


By comparison

TEMPERATURE -Thermocouple
Calibration purpose Mesurand Measurement range Best calibration uncertainty Measurement principle/Method reference (*) Calibration tools (reference, Equipement) Activities in Lab and/or on site
Thermoelectric couple Temperature                                                                                                                                                                        Electromotive Force Signal Voltage -40°C to 0°C ±0,4°C Method by comparison / PP200D022 rev 08 Ethylene/Glycol constant temperature bath                           Platinum resistance thermometer Multimeter                                     Melting ice point Lab
0°C to 80°C ±0,3°C
50°C to 200°C ±0,4°C Oil Constant temperature bath Platinum resistance thermometer Multimeter                                                 Melting ice point
150°C to 400°C ±0,5°C Bath of melted salts Platinum resistance thermometer multimeter
400°C to 500°C ±0,6°C
500°C to 700°C ±1,3°C Tubular furnace                                    S type thermoelectric couple Multimeter                                             Melting ice point
700°C to 1100°C ±1,4°C
1100°C to 1200°C ±1,6°C
1200°C to 1300°C ±2,1°C
1300°C to 1500°C ±2,4°C

Successful test campaign on neutron sensors

THERMOCOAX has finalized a test campaign on neutron sensors.

reacto Pool : experimental fixtureReactor Pool : experimental fixture

Despite stringent time constraint, a highly professional IJS team was prompt to react and welcome a team conducted by THERMOCOAX and relying on the best internationally recognized experts from different European nuclear organizations.

Multiple irradiation tests have been carried out.

IJS reactor being very well characterized, results are confirmed to match with our stringent expectations: perfect matching between theory and practical results!

An additional demonstration of the THERMOCOAX mature technology readiness.



THERMOCOAX has over 60 years of expertise in instrumentation and heating solutions. It provides solutions in the world of nuclear, aerospace and semicon industries. It design, qualify and manufactures sensors for harsh environment with a focus on nuclear on temperature and radiation measurement.

 About IJS Jozef Stefan Institute

IJS Jozef Stefan Institute in Slovenia has over 50 years of expertise. Reactor Infrastructure Centre (RIC) department is operating a  TRIGA Mark II reactor. Reactor physics department is directed mostly towards development of new calculation methods for research and power reactors. Several program packages for reactor calculations both for TRIGA research reactor and Krško nuclear power plant. Jozef Stefan Institute also study advanced fourth generation reactors, advanced neutron sources and data and materials for fusion technology are also studied.


TRIGA reactor
TRIGA reactor

Heating System for SMA actuators

You are looking to replace your pyrotechnic actuators with shape memory alloy technology for your space applications ? We have the most advanced industry-proven solutions.

Spacecrafts require variety of mechanisms to accomplish the mission. The typical functions are deployment, articulation, positioning, displacement.

Pyrotechnic separation nuts, paraffin actuators and others devices are hazardous for the satellite, regarding shocks waves generation and potential risk of contamination.

Shape Memory Alloy ( SMA ) technology equipped with inner heating element, offers smooth and slow behavour, higher cleanliness result and good vibration & shock resistance.

Thermocoax addresses this new market with miniature and powerfull heating element, same components already demonstrated on propulsion and thermal management on board satellite.

Main applications are single one time used valve, Hold Down & Relieve Mechanism (HDRM), Pin Puller, deployment Hinge.

Heating SMA
Heating coil

In-Core water level detector

Over the last decade, THERMOCOAX has developed a range of Ex-Core accident resistant cabling systems and In-Core instrumentation assemblies for Gen 3 reactors.

Based on THERMOCOAX unique expertise and taking profit of the extreme robustness of its MIneral Cable technology, THERMOCOAX has developed, tested and qualified a Reactor Pressure Vessel Level (RPVL) detector.

Before making the detector commercially available, THERMOCOAX has partnered with SIET ( to verify detector functionality at normal and abnormal conditions.

Some results have been published during the latest BEPU 2018 Conference. Click here to read an abstract

THERMOCOAX Nuclear team remains available for further information.

Innovative flange immersion heaters for liquid fuel


The project to develop a high-efficiency immersion heater started a long time ago at Thermocoax with a particular R&D project for high purity aluminium foundries.


Then we decided to adapt our technology to heating applications for the storage of heavy fuel. We designed an innovative flange immersion heater offering longer lifetime than existing solutions.

The technology is based on THERMOCOAX Mineral Insulated Cables that offers high reliability, high resistance, long lifetime and a fully insulated heating solution.


A full range of Flange Immersion Heaters low density is now available with a total length above the flange of maximum 2 meters.

To respond to the needs of fuel storage applications in tanks where the accessibility is reduced and where small footprint heating systems are requested, we limited the length of the immersion heaters and made our design with DN100 & DN200 flanges only.

The challenge was to develop a design with high total power, a Low power density and a small footprint while offering a natural movement of the fluid through the heater.

Another challenge was to make a comfortable maintenance design, with a strong mechanical resistance and that can resist the immersion in petroleum-based liquids with 100% energy efficiency.


We based the design on a strong mechanical stainless steel structure with mineral insulated heating cable spiralled and firmly fixed on the structure.

In the middle of the heater, a stable Stainless steel square tube is welded to the flange. Another construction is fixed on this tube so that a solid essential strength is created.

The heating cables are held by particular carrier profiles which are connected to stainless steel discs and fixed to the middle tube.

We managed to make a design where each heating cable is independent, and due to an innovative assembly, each heating cable can be replaced independently for easy maintenance of the Immersion Heater on site.

Mineral insulated cables with 316L stainless steel sheath are used to offer to the heater a high resistance for immersion in main petroleum-based liquids and also asphalt, tar or other dense or highly viscous components.

We also wanted to offer a solution with better fluid circulation through the heater and with more contact between the fluid and the heating surface than with existing solutions on the market.

To meet this need, THERMOCOAX ISOPAD Immersion Heaters can have up to 3  layers of heating elements while keeping enough space for fluid circulation. The multilayer design increases the contact surface between the fluid and the heaters for a better heat transfer efficiency.

The clearance between two spires for the movement of the fluid through the heater is between 9mm and more than 15mm depending on the total power of the Immersion Heater.

All our immersion Heaters can be manufactured with an integrated thermocouple or PT100 for temperature control, with flange with screw plug and junction box.


  • Fuel, light diesel fuel, standard diesel fuel, maximum load 1 – 2 w / cm², materials: 321, 316l
  • Heavy fuel, maximum load 0,5 – 3,5 w / cm² according to grade, materials: 316l
  • Diesel, kerosene, maximum charge 3 – 3.5 w / cm², materials: 316l
  • Machine oil, maximum load 2 – 3.5 w / cm², materials: 316l
  • Mineral oil, maximum load 0,5 – 3,5 w / cm² according to temperature, materials: 321, 316l
  • Lubricating oil, maximum load 2,3 w / cm², materials: 321, 316l
  • Asphalt, tar and other heavy or highly viscous components

High-end heating solutions for SEMICON ALD deposition processes

THERMOCOAX is involved in the worldwide SEMICON market with High-end heating solutions based on Mineral Insulated cable technology.

We work on many levels of the wafer manufacturing process such as lithography, deposition, etching, ion implantation, or annealing.

With the evolution of the technology of 3D transistors, we focused our development on the ALD deposition process.

We meet the requirements of the SEMICON market in term of repeatability, temperature uniformity, control in production, quality monitoring, and COPY EXACT High volume manufacturing.

Due to our 60 years of experiences in high tech projects,  our engineering capability, our production tools, our control processes, our quality procedures and our adaptability are fully in line with the requirements of our SEMICON OEM customers.

We have decided to present in this paper our development on heating chucks for ALD processes

We have developed heating chucks dedicated to the SEMICON ALD, offering a high thermal uniformity on all the surface of the chuck, a great flatness and high dimensional stability, with no brazing presence outside the chamber.

We first focused our studies on the temperature uniformity over the entire surface of the chuck at High-temperature.

We started with the prototyping phases with our OEM customers.

Each ALD process has his own specifications. So, in order to better meet the needs of our customers, we set up a team of engineers dedicated to the SEMICON market.

We have acquired in-house testing tools, and we developed our own test systems.

Up to date, we have developed chucks with up to 7 separate heating zones.

A thermocouple type K, N or J well positioned makes it possible to control the temperature of each heating zone independently.

We manage to develop multizone heating chucks with High-temperature uniformity responding to the SEMICON ALD specifications :

Complex thermal FEA – 3D THERMAL MODELING – 1.6°C surface homogeneity



The flatness of the heating chuck is also one of the most important parameters in the ALD specifications.

We work on chucks with diameters up to 450mm (18 “).

We design, machine the chucks in-house, and control the dimensions with high-performance tridimensional CMM control facilities.

Those metal chucks can be of stainless steel, Inconel or special Alloy offering high dimensional stability.

  • Critical dimensional tolerances

 We adapt the feedthrough by offering custom bushings and flanges.

 Our heating chucks are designed to be used in an ultra-high vacuum environment.

  • UHV Vacuum < 10-7 Pa

THERMOCOAX has developed specific High-temperature ceramic / metal connectors compatible with high vacuum.

Because of the cleaning operation necessary for an ALD process, we developed metal chucks with a specific alloy that can resist the aggressive cleaning gas withstanding.

We also offer optional:

  • Cooling channel
  • Gas line
  • Vacuum wafer sucking
  • Anti-slice grooving



 To ensure the quality requirements of the SEMICON market, THERMOCOAX built a new factory in France fully dedicated to the SEMICON market with a dedicated R&D & manufacturing team.

We manufacture series according to the COPY EXACT specifications of our customers.

Our manufacturing process is fully controlled :

– Traceability,

– Subcontractor assessment,

– Internal & External audits

– Regulatory compliance

We set up an organization in project mode to manage large production programs for a permanent improvement of our performances.

Our industrializing performance is controlled by scores :

  • Failure mode and effects analysis (FMEA)
  • Statistical Process Control (SPC)
  • Process Flow
  • R&R calculation method

For High Volume Manufacturing, THERMOCOAX works with the strategy  of permanent improvement in terms of :

  • Design
  • Manufacturing process
  • Cost reduction

  THERMOCOAX offers high adaptability to customers specific requests.

THERMOCOAX has a full scaled presence in the US and serves ASIA directly.


THERMOCOAX to build Magnetic Diagnostics Flux Loops Cable Assemblies for ITER

THERMOCOAX, the expert in nuclear cabling systems and instrumentation ,has been awarded a contract by ITER.

THERMOCOAX will manufacture Magnetic Diagnostics Flux Loops Cable Assemblies. This innovative cable assemblies will be based on Mineral Insulated cable technology and will be installed in the ITER Vacuum Vessel.

This project represents an important milestone in THERMOCOAX nuclear business unit expansion and pave the way for others applications in FUSION reactors.

THERMOCOAX offers support to its customers through the design, delivery and support phases of a program.


THERMOCOAX has over 60 years of expertise in cabling solutions and instrumentation. It provides solutions in the world of nuclear, aerospace and semicon industries. It design, qualify and manufactures sensors for harsh environment with a focus on nuclear on cabling solutions and connectors.

About ITER

ITER (“The Way” in Latin) is one of the most ambitious energy projects in the world today. 35 nations are collaborating to build the world’s largest tokamak, a magnetic fusion device that has been designed to prove the feasibility of fusion as a large-scale and carbon-free source of energy.
The heart of a tokamak is its doughnut-shaped vacuum vessel. Inside, under the influence of extreme heat and pressure, gaseous hydrogen fuel becomes a plasma.