Deliverables Room-temperature plasma-assisted wafer bonding technology Wafer bonding is a viable technique of joining materials. In its standard form it requires a cleaning step followed by materials merging and a high temperature step. For many applications requiring the merging of different materials the high temperature step is unacceptable. This is true for instance when joining materials with large difference in thermal expansion coefficients or when the pieces to be joined contains materials or structures that do not withstand elevated temperatures. In this project a room temperature bonding process is investigated. The method relies on oxygen, nitrogen or argon plasma exposure of the surfaces to be merged. By this technique mechanically and electrically stable structures can be achieved at room temperature without need for annealing procedures. The primary application area in this project is manufacturing procedures for microsystems, but potential applications exist in all areas of microelectronics where different materials are to be joined. One example is the use of wafer bonding in its standard (high temperature) form for manufacturing of silicon-on-insulator materials. A room temperature bonding technique will largely increase the possibility of joining otherwise incompatible materials. Thin-film anodic bonding using evaporation of glass The overall objective of this result is to enable industrialisation of thin-film anodic bonding of silicon to silicon using electron-beam evaporation of boron- silicate glass. Thin-film anodic bonding represents an attractive alternative to conventional bulk-glass anodic bonding since the former technique a.o. eliminates problems with thermal expansion mismatch between the wafers and makes complex functionality in both wafers possible. The results include specification of process parameters and development of a thin-film process for glass deposition (e-beam evaporation). Following this a series of bonding experiments of plain substrates has been carried out to optimise the fundamental bonding process. After this we have been working on methods for using thin-film anodic bonding for solving some of the key problems concerning encapsulation of MEMS-structures such as encapsulation of electrical interconnections (lateral and vertical) and sealing of cavities. These results are described in internal reports. After project completion thin-film anodic bonding will be part of MIC's process portfolio, which will be offered to MIC's industrial partners. Anodic bonding for sensor encapsulation and packaging The overall objective of this result is to enable the encapsulation of silicon/glass sensors using metallic packaging. Applications are in the fields of sensors used in harsh environment or requiring strong connections with the outside environment. Methods for combining fluid connectors with anodic bonding are to be explored for the realisation of a flow sensor demonstrator. At present, work is in progress to assess anodic bonding of metal to glass for this purpose. Preliminary experiments have shown that stable bonding can be achieved between Pyrex and alloys with a similar thermal expansion coefficient such as Kovar and Alloy-42. After project completion, metal anodic bonding would be part of IMT's process portfolio, which will be offered to IMT's industrial partners. Searching for OpenAIRE data... There was an error trying to search data from OpenAIRE No results available
