High-throughput laser annealing system for magnetic sensor manufacturing debuts

Sensor manufacturer Crocus Technology is among the first to install the new system for production applications.

Tunnel magnetoresistance (TMR) sensor wafers processed with the microVEGA xMR selective laser annealing system from 3D-Micromac.
Tunnel magnetoresistance (TMR) sensor wafers processed with the microVEGA xMR selective laser annealing system from 3D-Micromac.
(Credit: 3D-Micromac)

Strong growth in the magnetic sensor device market is being driven by increased demand for magnetic sensors in consumer electronics, such as rotation sensors and e-compasses in smartphones and wearables, linear position sensors and angle sensors for brushless DC motors, and in automotive applications such as power steering angle detection and electronic throttle control. It is estimated that the magnetic sensor market will grow to $6.2 billion in 2025.

Crocus Technology (Santa Clara, CA), which manufactures tunnel magnetoresistance (TMR) sensors, has purchased and installed a microVEGA xMR selective laser annealing system in its Santa Clara facility, where the tool will be used in the production of its TMR sensors utilized in consumer electronics and industrial and Internet of Things (IoT) applications.

The microVEGA xMR system, made by laser micromachining systems maker 3D-Micromac AG (Chemnitz, Germany), is reportedly the first industrial selective laser annealing system for magnetic sensor formation. Incorporating a highly flexible, high-throughput tool configuration with on-the-fly spot and variable laser energy, the system accommodates both TMR and giant magnetoresistance (GMR) sensors, as well as easily adjusts magnetic orientation, sensor position, and sensor dimension—making it an ideal solution for magnetic sensor production.The microVEGA xMR selective laser annealing system from 3D-Micromac.The microVEGA xMR selective laser annealing system from 3D-Micromac.(Credit: 3D-Micromac)

Thermal annealing has traditionally been used to maximize the magnetoresistance effects of GMR and TMR sensors. However, this approach requires multiple process steps to produce sensors with different magnetic orientations that are mounted in multi-chip packages or processed as integrated monolithic packages. New approaches were needed to reduce these process steps, simplify the overall production flow, provide scalability to smaller footprint, and enable more cost-effective production of integrated monolithic sensor packages.

The microVEGA xMR system provides a flexible, robust approach to integrated magnetic sensor formation that enables new sensor designs, lower production cost, and scale-up to production more quickly. It provides several advantages over thermal annealing for magnetic sensor manufacturing, including higher precision to enable the processing of smaller magnetic device structures, which results in more devices per wafer, as well as the ability to set different reference magnetization directions on sensors across a single wafer.

The system’s on-the-fly spot and variable laser energy provide selective heating of the pinning layer in each sensor to “imprint” the intended magnetic orientation. Magnetic field strength and orientation is adjustable by recipe, while high-temperature gradients ensure low thermal impact. This allows sensors to be processed directly next to read-out electronics as well as closer together, and enables the production of smaller sensors—freeing up space for processing more devices per wafer. The result is reduced process steps, simplified production flow, higher yield, and more cost-effective production of integrated monolithic sensor packages.

Tino Petsch, CEO of 3DMicromac, says “We are pleased to have had the opportunity to work with Crocus Technology on one of the first installations of this new product, where they were able to take advantage of our wide range of services, including application and process development as well as contract manufacturing, in order to accelerate their path to production for their new sensor products field direction (orientation) accuracy.

For more information on the microVEGA xMR selective laser annealing system, please visit 3d-micromac.com.

Source: 3D-Micromac press release via PR Newswire – November 10, 2020

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