Wafer-Level Magneto-Optic Kerr Measuring Instrument

Wafer Moke can provide up to 2.5T vertical magnetic field/1.3T in-plane magnetic field, and the strong magnetic field can induce the flipping of the free layer, reference layer and pinned layer of the vertical anisotropic magnetic random access memory (MRAM) film stack;
Ultra-high Kerr detection sensitivity, which can characterize the subtle magnetic changes of different film layers at the same time. Combining laser point-by-point detection with scanning imaging can quickly create a global map of wafer magnetic properties, assisting process optimization and yield control.

Performance indicators and advantages

▹Sample size: supports up to 12-inch wafer testing and is backward compatible, supports fragment testing;
▹Magnetic field: the maximum vertical magnetic field is better than ±2.5 T, and the magnetic field resolution is 1 μT;
▹Magnetic detection sensitivity: the detection degree of Kerr rotation angle is better than 0.3 mdeg (RMS), suitable for magnetic characterization of multilayer film stacks;
▹Sample repeat positioning accuracy: better than ±1 μm, static jitter ≤±0.25 μm.

Functions and Application Scenarios

▹Vertical hysteresis loop measurement of MRAM stacks and device arrays (Polar Kerr for MRAM);
▹Vertical hysteresis loop measurement of magnetic storage media such as disks (Polar Kerr for PMR Disk);

▹Measurement of in-plane hysteresis loop in the film stack of the magnetic sensor;
▹Automatically extract hysteresis loop information, such as free layer and pinned layer Hc, Hex, Ms, etc., which can quickly draw the distribution map of the magnetic properties of the wafer;
▹The system presets scanning modes such as single point, array, and ring distribution, and supports the import of custom position lists;
▹The system provides manual loading or fully automatic operation to meet R&D/production needs.

Measurement results of hysteresis loops of perpendicular anisotropic magnetic tunnel conjunctival stack

Coercive field characteristic distribution diagram of 8-inch perpendicular magnetic anisotropy wafer