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Surface Micro-Machined Encapsulation on Wafer Level


Developed Know how: Within the project a thin film technique to encapsulate accelerometers with a thin film Epi-Poly Silicon Cap was developed. Two different sacrificial processes were developed. Cheaper Sensors: The project goal to fabricate cheaper accelerometers by the omission of the chip area of the bonding frame used in the current technology was successfully achieved. We have reached approximately 1/5th of the original sensor costs.
Throughout the SUMICAP project STS had close contact with IMEC and Bosch, resulting in an exchange of know-how related to packaging and equipment and process requirements. This information has been instrumental in improving STS' equipment and processes for both the SUMICAP process and for Advanced Packaging. Of commercial importance to STS are the development of pre-competitive processes and hardware that have directly resulted from the project, namely: - A suite of processes for the packaging (via encapsulation) and micromaching of MEMS and other devices. Process know-how gained includes, deep silicon etch, SiGe etch, sacrificial etch of Si and Sio2, SiO2 deposition, BPSG deposition. - Fully Characterised BPSG reflow process for the sealing of the membrane layer. A BPSG reflow process also has applications within the fabrication of optical waveguide cladding layers and the full characterisation data has had an immediate impact on sales in this area. - New showerhead design and clean process for PECVD, which have been developed as a direct result of input from Bosch and IMEC. - A new range of process platforms were released in July 2003 which have been targetted at meeting the requirements of production MEMS and MEMS packaging manufacturers such as Bosch. The market requirement data has been significantly influenced by input from Bosch. Overall the project has provided STS with know-how to launch a range of enabling processes for advanced packaging. These processes are moving STS' entry into advanced packaging business, which has grown from 4% of equipment revenues in 2002 to 22% in 2003. Through active dissemination of the SUMICAP results, STS has been able to position itself as the technology leader in encapsualtion technologies for MEMS packaging. STS predicts strong growth in the sector in the next 3-5 years as well as the immediate creation of jobs within STS' packaging group, it is anticipate that further job creation is a certainty. Outside of STS the SUMICAP process is an enabling technology that will drive down the cost of MEMS devices through a reduction in packaging costs. This will enable the commercialisation of a range of MEMS devices that are currently not commercially viable. These will have wide ranging social implications, notably within healthcare and diagnosis, improvement of quality of life, chemical identification and improvement of leisure time. The demand for these devices will lead to further job creation.