Two kinds of measurement
A semiconductor fab and test floor make two very different kinds of measurement. The first is electrical characterisation of the device itself: current–voltage curves, leakage, threshold voltage, capacitance, timing. That is the work of source-measure units, parametric analysers and automatic test equipment from vendors such as Keysight, Keithley, Advantest and Teradyne. These instruments force a voltage or current and measure the other, down to femtoamperes, and they bring their own calibration and software. There is no general calculator on this site for that work.
The second kind is the measurement of the conditions around the wafer and the device: temperature, vacuum, gas pressure, humidity and vibration. These use the same sensors as any process industry, and it is here that reference tables and unit conversions are needed every day.
Temperature: chucks, furnaces and ovens
Probers and thermal chucks hold the wafer at a set temperature during test, commonly somewhere between −40 and 150 °C or beyond. The chuck temperature is read by platinum resistance thermometers connected with four wires, so that lead resistance does not enter the result. A PT100 reads 157.325 Ω at 150 °C; the PT100 calculator gives the value and the tolerance of the element class at any temperature, which is the first number to know when two chucks disagree.
Diffusion and oxidation furnaces run near and above 1000 °C, where platinum–rhodium thermocouples of types R, S and B are used. Their output is small: a type S thermocouple gives 9.587 mV at 1000 °C and changes by only about 11.5 µV per degree, so one degree of error is a matter of a few microvolts at the terminals. The thermocouple calculator converts with cold-junction compensation, and the type S and type B pages list ranges and tolerance classes.
Burn-in and high-temperature operating life tests stress powered devices in an oven. A common qualification condition, described in JEDEC JESD22-A108, is 1000 hours at a junction temperature of 125 °C or more. Oven and device case temperatures are logged with type K or T thermocouples; type K gives 5.124 mV at 125 °C. What the test needs is the junction temperature, which is the case temperature plus the rise caused by the device’s own dissipation, and no temperature sensor reads that directly.
Vacuum and pressure: a unit problem
Process chambers are specified in Torr and millitorr in much of the industry, in pascals and millibars elsewhere, and facility gases in psi, bar or kPa. One Torr is 133.322 Pa or 1.3332 mbar, so a 100 mTorr process is 13.33 Pa. Cleanroom pressurisation and exhaust are small differential pressures in pascals or inches of water: 25 Pa is 0.1004 inH₂O. The pressure unit converter shows all sixteen units at once.
Two cautions. A capacitance manometer measures pressure directly, but thermal-conductivity and ionisation gauges infer it from a gas property and read differently for different gases; converting units does not correct that. And vacuum gauges are absolute, whereas most line-pressure transmitters are gauge instruments referenced to atmosphere.
Humidity and vibration
Cleanroom humidity is held within a narrow band because it affects electrostatic discharge, resist processes and corrosion. A room at 22 °C and 45 % relative humidity has a dew point of 9.5 °C; any surface colder than that, such as a chilled-water line, will collect condensation. The dew point calculator converts between relative humidity, dew point and absolute humidity.
Lithography and metrology tools are sensitive to floor vibration, which is specified as RMS velocity in micrometres per second in one-third-octave bands, the generic VC curves running from 50 µm/s (VC-A) down to about 3 µm/s (VC-E). Sensors report acceleration; the vibration converter turns acceleration, velocity and displacement into one another at a given frequency. It works on a single frequency, so it helps with reading a specification or a sensor datasheet, not with evaluating a measured spectrum against a criterion.
Updated October 11, 2026