Digital Microscopes
Observation and Measurement of Power Semiconductors (Power Devices) Using Digital Microscopes
Unlike typical semiconductors that handle data, such as CPUs and memory, power semiconductors control electric power and are called power devices. This section introduces examples of how to observe and measure power semiconductors (power devices) using digital microscopes.
What is a Power Semiconductor?
Although not defined clearly, semiconductors that control a large amount of voltage and current and have a rated current of 1 A or more are generally called power semiconductors.
Functions of Power Semiconductors
A: Inverter a: Direct current
b: Alternating current
Inverter:
Converts direct current (DC) into alternating current (AC).
A: Converter a: Alternating current
b: Direct current
Converter:
Converts AC into DC.
A: Frequency conversion
a: Alternating current
Frequency conversion:
Converts the AC frequency.
A: Regulator a: Direct current
Regulator:
Converts the DC voltage.
Power Semiconductor Types and Characteristics
Power diode
Function: Rectification
Power diodes conduct current in one direction with no switching.
Power transistor
Function: Switching and amplification
- Thyristor
Thyristors were the first power transistors to become available and are characterized by a high withstand voltage. - Power metal-oxide-semiconductor field-effect transistor (MOS FET)
Power MOS FETs are characterized by high speed and high frequency. These power transistors are commonly used for products with a low withstand voltage range up to approximately 200 V. Typical products are IT devices including laptops. - Insulated-gate bipolar transistor (IGBT)
IGBTs are characterized by high withstand voltage, high speed, and high frequency. These power transistors are commonly used for products with a medium to high withstand voltage range of 200 V or higher. Typical products include electric vehicles, hybrid vehicles, and railroad cars.
Power Semiconductor (Power Device) Observation and Measurement Examples Using Digital Microscopes
These are the latest examples of observation and measurement of power semiconductors using KEYENCE’s VHX Series 4K Digital Microscope.
3D measurement of probe dents on a power semiconductor
1000×, coaxial illumination
3D measurement of a probe dent on an IGBT
1000×, coaxial illumination
Observation of a defective part on a power semiconductor
Surface irregularities are visualized in Optical Shadow Effect mode, which allows for quick determination of whether defective areas were caused by adhesion or dents.
200×, coaxial illumination
Optical Shadow Effect mode (Color Map) image
Observation of a material for power semiconductor wafers
Using the ring-reflection removal function eliminates glare from the surfaces.
100×, ring illumination, normal image
Image after ring-reflection removal
Observation of fillers in a power semiconductor mold resin
Using the HDR function improves contrast, allowing for accurate profile measurement of fillers.
1000×, coaxial illumination + HDR
Automatic area measurement image
