Test Identifies Failed Vias

Munich, Germany: Infineon unveiled a method that can avoid one of the most common causes of defects in the production of highly integrated semiconductor circuits: the electrical failure of via contacts.

Via stands for “vertical interconnect” and refers to the contact between two metal layers in ICs. The company developed the new method in collaboration with the Regensburg University of Applied Sciences.

Today’s ICs contain millions of transistors interconnected by several layers of metal wiring. It’s the via components that connect the metal conductors between the layers. A via is extremely small: when manufactured in a 0.13 m process, it has a diameter of 200nm, which makes it about 300 times thinner than a human hair. A modern microcontroller of around half a square centimetre in size contains in excess of ten million vias.

It’s impossible to optically or electronically control or measure the quality of a via during the manufacturing process. In fact, sometimes, electrical failure of just a single via can impair the functionality of an entire microcontroller.