Wafer measuring system

Kerr effect (MOKE)laseroptical

Using the poloidal magneto-optical Kerr effect (MOKE), the magnetic properties of wafer stacks are quickly and globally detected. Non-contact measurement avoids damage to the wafer by traditional magnetic characterization, and can be applied to sample detection before and after patterning. 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);