ORGANIC MESOMEMS INTEGRAL ACCELEROMETER

ORGANIC MESOMEMS INTEGRAL ACCELEROMETER

PROBLEM

Increased levels of integration in the printed circuit board or packages of an electronic product allow size, weight and cost reduction.  Embedding mesoMEMS devices such as sensors requires the development of novel processes and structures compatible with low temperature printed circuit board fabrication processes and materials.  Monolithic micro-accelerometers are currently used in many applications.  These are fabricated in silicon using semiconductor fabrication processes.  Although capable of producing very compact accelerometer structures, these processes are inherently expensive and complex.

SOLUTION

Figure 1 shows an accelerometer structure fabricated in a printed circuit board or semiconductor package using conventional organic and metal materials and low cost, low temperature processing.  The invention is novel in its use of conventional printed circuit board materials to form three-dimensional structures with bridging or cantilevered elements.  Such structures have previously been demonstrated only in silicon, using anisotropic etching techniques that are not compatible with low cost, low temperature, ambient environment (non-vacuum) printed circuit board processes.

The process involves two instances of latent patterning.  The first is the creation of a latent exposure in the first layer of photodielectric, which is not developed until late in the fabrication sequence, after additional layers of various materials have been constructed on top of the first photodielectric layer.  This novel latent...