The swm microVEGA-xMR system can be used to process both GMR (Giant Magnetoresistance) and TMR (Tunnel Magnetoresistance) sensors. The advantages of the system lie in the cost-efficient production of monolithically integrated sensor chips in just one production step. This is made possible by the use of an on-the-fly laser spot, which can be flexibly adapted to different magnetic sensors in terms of geometry and pulse energy.

Adaptation to sensor positions and dimensions as well as different magnetic field orientations is possible simply by changing recipes. All this makes the laser pinning system an ideal tool for magnetic sensor processing. Crocus Technology, a manufacturer of TMR sensors, is already successfully using a microVEGA-xMR system. The Californian company has been able to significantly increase productivity in its production.

Higher packing density with improved sensor quality

Compared to conventional annealing processes in magnetic sensor production, the technology used in the microVEGA xMR is characterized, among other things, by higher precision and thus allows the processing of smaller structures. The very good selectivity of the short-pulse laser allows a significant reduction in the distances between the sensors and the evaluation electronics, which significantly increases the number of components per wafer.

The very good energy homogeneity and repeatability improve the quality of the sensors. The accuracy in the alignment of the magnetic field direction is ±0.010° - another important criterion for the production of sensitive sensors.

More cost-efficient production of magnetic sensors

With the system, different reference magnetic field directions can be realized on a single sensor chip in a single production step ("pinning process"). The magnetoresistive effect in GMR and TMR sensors is achieved through the targeted alignment of magnetic layers. Up to now, this has been achieved using a global magnetic field with simultaneous heating of the entire wafer. However, this approach requires a complex process chain up to the finished sensor in a multi-chip package.

Selective heating with the laser spot aligns the sensors in the monolithic chip package in a sub-ms cycle. The new annealing process is particularly selective and fast - up to 500,000 sensors per hour can be processed with a typical wafer design. All system parameters such as pulse energy, sensor dimensions, distance between sensors and magnetic field strength can be set purely based on the recipe.

The demand for magnetic sensors is constantly increasing. In consumer electronics, for example, they are used as electronic compasses in smartphones and wearables. Magnetic sensors for rotation are installed as angle sensors in brushless DC motors (BLDC) and in the automotive industry as steering angle sensors or in electronic gas pedal pedals.