Online proceedings - EDA Publishing Association

11-13
May 2011, Aix-en-Provence, France
Figure 7: Package roadmap of yaw rate sensors for ESP
specific readout circuit (ASIC) in a SOIC16w package (Fig.
6). With this approach the footprint of the sensor could be
reduced by 70% to the two predecessor sensors.
Figure 5: SEM picture of Bosch’s first micromechanical yaw rate sensor
(combination of bulk and surface micromachining)
In 1998, as ESP systems were starting to gain broader
market share, Bosch introduced its first silicon
micromachined yaw rate sensor [2]. The sensing elements
were manufactured using a mixed bulk and surface
micromachining technology and have been packaged in a
metal can housing (Fig. 5).
Growing demand for new additional functions of ESP and
of future vehicle dynamics systems – like Hill Hold Control
(HHC), Roll Over Mitigation (ROM), Electronic Active
Steering, and others – required the development of
improved inertial sensors with higher precision at lower
manufacturing costs. These goals have been achieved by the
3 rd generation ESP sensors [3], a digital inertial sensor
platform based on cost effective surface micromachining
technology, which was released in 2005.
Fig. 7 shows the development of the first mechanical yaw
rate sensor to the current combined inertial sensor SMI540
REFERENCES
[1] A. Reppich, R. Willig, “Yaw Rate Sensor for Vehicle Dynamics
Control Systems”, SAE Technical Paper 950537 (1995).
[2] M. Lutz, W. Golderer. J. Gerstenmeier, J. Marek, B. Maihöfer, S.
Mahler; H. Münzel, U. Bischof, in Proceedings of Transducers '97,
Chicago, IL, June 1997, p. 847-850.
[3] U. Gómez, B. Kuhlmann, J. Classen, W. Bauer, C. Lang, M. Veith,
E. Esch, J. Frey, F. Grabmaier, K. Offterdinger, T. Raab, R. Willig,
R. Neul, “New Surface Micromachined Angular Rate Sensor for
Vehicle Stabilizing Systems in Automotive Applications”, in
Proceedings of Transducers ’05, Seoul, June 2005, p. 184-187.
Recent development at Bosch resulted in the world’s first
integrated inertial sensor modules, combining different
sensors (angular rate and low-g acceleration sensors) and
various sensing axis (x, y) into one single standard mold
package at low size and footprint (SMI540). In detail, the
sensor consists of a combination of two surface
micromachined MEMS sensing chips – one for angular rate,
one for 2-axis acceleration – stacked onto an application
Figure 6: Combined inertial sensor SMI540 for ESP
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