Hamamatsu News 2 / 2017

News 2017 Vol. 2 8 Sealed type MFX with world’s highest level of performance First of all, we want to ask you, what exactly is an MFX or microfocus X-ray source? Yagi: The MFX is an X-ray source that generates X-rays by focusing electrons through an electron lens to strike a very small area on a metal target in a vacuum. Since X-rays are then emitted from the focal spot on the metal target, the smaller the focal spot, the clearer and sharper the acquired X-ray image even when magnified geometrically. For example, the photo on the bottom is the X-ray image of an electronic component showing the internal structure down to the micrometer scale. Object X-ray focus Transparent image R&D Interview Suzuki: The MFX is available in two types. One is the sealed type while the other is an open type. The sealed type uses a vacuum tube called an X-ray tube, while the open type creates a vacuum state by a combi­ nation of a metal container and vacuum pumps. The sealed type is compact and lightweight allowing easy maintenance and lower power consumption. In contrast, the open type is large and requires regular maintenance yet has a replaceable cathode. Using the high precision cathodes gives more precise images. Can you please explain what a transmission target is? Tanaka: As mentioned earlier, the MFX generates X-rays by making electrons strike the metal target. There are two metal target structures where electrons collide. One is the transmission target and the other is the reflection target. The transmission target can form a small X-ray focal spot compared to the reflection target. The smaller the X-ray focal spot, the higher the resolution will be. So, as you might guess, this means that an open type MFX having a transmission target can acquire high precision images. Suzuki: However, the transmission target usually requires a large elec­ tron lens with an electromagnetic focusing coil to achieve features such as a wide radiation angle, high magnification, and high resolution. This is one reason why open type MFXs using a transmission target have to be a large size. We talked to members of the project that achieved a plan spanning more than 10 years to develop this new model spawned by expectations on the market. Now let’s hear about the background and groundwork leading to completion of this project. An innovative step to expand X-ray inspection applications A sealed type MFX with a transmission target is now on the scene! X-ray inspection is a technique that provides information about the internal structure of objects such as semiconductor devices, which cannot be seen from the outside. Its accuracy depends on the MFX or microfocus X-ray source used to generate X-rays. We have just unveiled a new model MFX that combines the advantages of the “open type” having high accuracy and a “sealed type” offering easy maintenance. This new model is a sealed type MFX using a “transmission target” which has been difficult to install in sealed types up till now. It delivers high resolution, high magnification, and a wide radiation angle, making it an ideal replacement for the “open type” currently ranked as a high-performance MFX model. Example X-ray image of an electronic component