Temperature monitoring of solar cells and semiconductors

In the solar and in the semiconductor industry, non-contact temperature measurement aids in the continuous monitoring of the production process and thus helps improving the production procedure. By detecting slightest changes in the thermal behavior, possible malfunctions can be detected and solved easily and reliably. The thermal imagers of Optris are especially suited for these tasks. Thermal imagers are not the only option, though. Cost-effective alternatives can be found in our technical article Temperature monitoring of assembled circuit boards.

Silicon Wafer temperature measurement

Temperature measurement of silicon wafers in the semiconductor manufacturing process has always been an important metric that plays a large role in product quality.
However, in the low-temperature vacuum process between room temperature and about 200 °C, there are few commercially viable temperature measurement methods available.

The use of infrared remote sensing has many practical advantages but has not been widely adopted due to the transmissive characteristics of Silicon in the infrared region.
Silicon is roughly 55 % transmissive in the region between 1µm and 10 µm where many commercially available sensors are responsive.
However, silicon becomes largely opaque between 11.5 µm and 14 µm so infrared sensors responsive only in this region would gather 90 % of the energy used for temperature measurement from the wafer and not from heat emissions transmitted through the wafer from the other side.

Optris PI 640 and Xi 400 cameras can be equipped with a new long-pass filter which will transmit beginning at 11.5 µm.

Recommended devices:
Thermal imager optris PI 640
Thermal imager optris Xi 400

Quality control of solar cell modules

Infrared cameras are essential instruments for the quality control of solar cells. One possibility of testing is the periodical modulated exposition of the solar cells to light (Illuminated Lock-In Thermography). The separation of charge within the solar cell leads to leakage current at defective parts and thus to local hot spots. The hot spots can be detected by the infrared camera.

Recommended device: Thermal imager optris PI
Application note: Temperature measurement solar industry

Temperature monitoring of string soldering process

For the production of solar modules the temperature of wafers is captured during the string soldering process. This assures a reliable and efficient assembling process. Temperature measurement takes place on the silicium surface which is connected to the braze point. That’s how the quality of the homogeneity of the soldering is measured.

Recommended device: Thermal imager optris PI
Application note: Temperature measurement solar industry

Function tests of assembled circuit boards

More and more manufacturer of electronic components and circuit boards turn to the use of non-contact temperature measurement due to the increasing productivity of their components. The thermal behaviour can be captured and optimised through the use of modern infrared measurement devices – without influencing the measuring object.

Recommended devices: Thermal imager optris PI or
infrared thermometer optris CT LT
Application note: Function tests of assembled circuit boards