A Multilayer Ceramic Package For Silicon Micromachined Accelerometers

A novel ceramic package for a two-chip silicon accelerometer and the signal conditioning ASIC chip assembly has been developed with the advantage of being directly mounted on a PC board thus eliminating the need for additional mounting structures for automotive airbag applications. The hermetic package is designed to be mounted either in vertical or flat positions on a PC board, thus enabling the sensing directions of the accelerometer to be parallel or perpendicular to the plane of the PC board for front and side air bag applications. The package has been modeled for thermal stress induced during assembly and operating conditions. The dynamics of the package was determined using static, harmonic, modal, random vibration and transient dynamic modeling. Testing of the mounted package on the shaker shows flat frequency response to 4.5kHz. Temperature cycling on the unit between -40/spl deg/ and 85/spl deg/C shows no failures or performance degradation over 2400 temperature cycles.