What are the advantages of X-ray in detecting IGBT internal defects?

Date：2021-09-13 15:15:00Views：1200

IGBT is a composite fully controlled voltage driven power semiconductor device composed of bipolar transistor and insulated gate field effect transistor. It has two advantages: high input impedance of MOSFET and low on voltage drop of GTR.

IGBT module has the characteristics of energy saving, convenient installation and protection and stable heat dissipation. Most of the modular products sold in the market are such products. Generally speaking, IGBT also refers to IGBT module. IGBT is the central equipment of energy conversion and transmission, commonly known as power electronic equipment. As a national strategic emerging industry, it has been widely used in rail transit, smart grid, aerospace, electric vehicles and new energy equipment. With the common development of the concept of energy conservation and environmental protection, such products will be more and more popular in the market.

If there are a set of three small voids in the welding of IGBT chip connected to its radiator, and these voids are close to each other, heat can be avoided from the area under the equipment. Over time, the area above the gap may overheat, and the chip may have electrical failure, resulting in system failure.

Because IGBT is usually used for high voltage and high power, its failure is both expensive and dangerous. It is meaningful to find IGBT internal structural defects before they have the opportunity to fail.

The production process of IGBT is the same as that of ordinary semiconductor products. The industrial chain includes planning, production, packaging and testing. Domestic enterprises have a weak technical foundation in the field of IGBT, started late in industrialization, and accumulated insufficient central technologies such as planning, testing and packaging.

X-ray can perform non-destructive testing and imaging on IGBT. Rays can penetrate the radiator of IGBT module to complete useful testing. Local differences of images can be observed through the attenuation of penetrating rays.

X-ray detection equipment can detect a large number of IGBT modules. IGBT is the most common engine in hybrid vehicles, but it can also be used in traditional vehicles. IGBT will emit a lot of heat. If any structural abnormalities (such as voids or unbonded) disturb the heat dissipation path, it may fail due to overheating.

The most common defects in IGBT are air gap and bonding loss. X-ray imaging can successfully detect the gap in solder. Other common defects include warping or tilting of the ceramic raft (both will change the heat flow and break the chip) and the porosity of the solder under the chip. The IGBT module can be inspected by X-ray imaging before and after packaging. If it is imaged and tested before packaging, the defective parts can be repaired again.

The biggest advantage of X-ray detection is that the detection results are intuitive. Through the image display of the internal shortcomings of IGBT, the software automatically identifies and judges, improves the accuracy of X-ray detection and reduces the manual misjudgment rate. In the production process of IGBT, it not only ensures the product quality, but also provides a reliable basis for improvement in the R & D planning stage. X-ray testing equipment uses the X-ray transmission principle to test IGBT module, without additional cost, and the detection is fast and accurate. There are many X-ray detection products. X-ray detection has high-definition image and defect analysis function, which is highly praised by the industry and is a good choice.