Production of a Customized Temperature Sensor

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IST AG has concentrated one part of the development and manufacturing on high-end thin-film temperature sensors. This know-how is partially derived from the semiconductor industry and allows us to manufacture sensors with high accuracy, excellent long-term stability, high reliability and repeatability within a wide temperature range from -200 °C up to 1000 °C. Because of very small dimensions and low thermal mass, the thin-film temperature sensors exhibit a very short response time.

As easy as 1 - 2 - 3: Production of a Customized Temperature Sensor

Step 1: The production of a customized sensor starts by deposition of a thin film metallic layer onto a ceramic substrate. This process is done in our modern clean rooms classified as ISO5 (meaning a maximum of 3520 particles per m3). During deposition, various possibilities of customization such as deposition material (Pt, Ni, Ti, Cr or Au) and substrate thicknesses (from 0.1 mm to 0.6 mm) are available.

To ensure high quality and long term stable sensors wet chemical cleaning processes and high temperature annealing steps are performed after the deposition.

Step 2: The pattern of the sensor structure is defined by multiple steps. First, spin coating of a photo-sensitive resist onto the substrate. Afterwards, the photo-sensitive resist is structured by exposition. Finally, the photo resist is removed leaving only the sensor structure on the chip.

During this step, a specific mask must be chosen. The mask determines the final chip dimension, layout and the resistive structure of the sensor element. Various standard chip dimensions with different resistive values and layouts based on specific customer requests are offered by IST AG. Resistive values between 50 Ω and 100'000 Ω and multiple resistances on one chip are also possible.

Afterwards, screen printing is applied to the sensor pads to increase the strength between the pads and wires significantly improving vibration and thermal cycling robustness. The resistive structure of each sensor element is individually laser trimmed to achieve the required resistive accuracy. As a final process step in the clean room an additional passivation layer is screen printed onto the element for further mechanical and chemical protection.

Step 3: Reading the resistance values requires contact with the element. For SMD and Flip-Chip sensor elements, LMP or HMP solder are directly deposited on contact pads instead
of wires. Specific contact layers for bonding are also part of the IST AG portfolio. For wired sensor elements different configurations are welded directly on the chip on automated welding machines. IST AG offers a wide range of wire material e.g. Ag, Ni, Cu, Pt, Pt/Ni, Cu, Au/Ni, Ag/Cu etc. configured as both single core and stranded wire. In many applications insulation of the wires is required and IST AG is capable of directly welding insulated wires on the sensor element. When direct welding is not an option, extension of the lead wires with brazing or laser welding is offered. The length and diameter of the wire are customizable as well as the design of the wire configuration e.g. standard, inverted or perpendicular welding. Furthermore, configurations with 3 or 4 wires in various colors are also possible.

After welding the contact area is covered with fixation paste to increase robustness. Furthermore, aging and thermal cycling the sensor elements are now ready for visual and electrical quality inspection before shipping. A very sought after option is our metalized back side feature. This allows our customers to achieve excellent thermal coupling by soldering directly to a metal surface or cap (Cu, stainless steel, titanium etc.). Further options could be sensor elements inserted in round ceramic cases, injection molded
housings, fitting of connectors onto wires and sensor elements assembled in stainless steel probes.
Due to the outstanding accuracy and stability, our temperature sensors are used in all volumes - small and large - in industries ranging from heating-ventilation, medical, process control over aerospace and satellite applications (see insight article). With the excellent accuracy and stability of our sensors, the flexibility in our production and
competence of our employees, the IST AG sensors, whether it is a standard or a customized solution, offer the optimal price to performance ratio with a short production time.

READ MORE>>> Temperature and customized sensors from IST AG

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Welcome to IST USA

Innovative Sensor Technology IST USA Division is a fully owned subsidiary of Innovative Sensor Technology IST AG, based in Switzerland. We are a world-class manufacturer of thin-film platinum and nickel RTD temperature sensors, capacitive humidity sensors, mass flow sensors, conductivity sensors and bio sensors at the component level.

With our state-of-the-art manufacturing technology, we offer both standard and custom sensors to satisfy various applications. Our sensors cover requirements for system integrators in the process control, building automation, test & measurement, medical, automotive, and appliance industries.

IST USA Division offers high flexibility in sourcing and supporting our products. We offer in-house stock and on-site engineering support, which is available during our regular business hours for design, application, and after sales support.

Products:

IST produces four types of thin film measurement technology: RTD temperature sensors, capacitive relative humidity sensors, mass flow sensors and conductivity. Manufactured at the component level, these elements are available with a diverse range of standard and custom features.

Industries

The available and ever expanding IST portfolio satisfies the growing application possibilities across multiple industries.

Our wide product range is the choice of many renowned end customers and OEMs in these fields. As a result, our sensors are found in measuring instruments for various applications such as process control, HVAC and building automation, test and measurement, medical, automotive, and appliance. While our products are widely used in these industries, they are by no means limited to them.

  • Process Control
  • Building Automation
  • Test & Measurement
  • Medical
  • Auto
  • Appliance

Resources

For your convenience, we have included resources such as technical information, data sheets, application notes, and performance data for our sensors. If you have any questions regarding our products and their applications, please do not hesitate to contact us. We have engineers available to support you with all of your technical inquiries.

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