Liquid Crystal & FMI

Liquid crystal (LX) and Fluorescent Microthermal Imaging (FMI) are efficient optical analysis techniques used to detect and localize certain integrated circuit (IC) failures. They are non-invasive techniques performed from either the front or back of devices.

Liquid crystal (LX) and Fluorescent Microthermal Imaging (FMI) are efficient optical analysis techniques used to detect and localize certain integrated circuit (IC) failures. They are non-invasive techniques performed from either the front or back of devices.

Leakage current in semiconductor devices is likely to cause local heating along the current path. By coating the device surface with a material sensitive to temperature changes, one can detect the location of the hot spot.

Liquid crystals change phase at a given temperature. By bringing the device very close to this transition temperature with a hot chuck, one can detect very small local heating.

FMI relies on the temperature dependence of the fluorescent yield of an europium compound. It is harder to use than liquid crystal but it can give very quantitative results.

LX and FMI are powerful early-stage failure analysis techniques since they localize failures non-invasively such as:

• Detection of leakage current
• Temperature mappings