Cofiring process

Copper was used for metallization material because of excellent migration resistance. It is important for cofiring process to match the shrinkage behavior of copper metallization to that of LTCC material. Since the shrinkage of copper... 

Multilayered LTCC package plated with nickel and gold were prepared, and reliabilities of the package were evaluated. The copper sealing pattern was formed by cofiring process. The package was sealed with the Alloy 42 lid (20 mm X 20 mm) by gold—tin eutectic alloy. 

Master, R.N., Herron, L.W., and Tummala, R.R., Cofiring process for glass-ceramic/ copper multilayer ceramic substrate, IEEE Transactions on Components, Hybrids, and Manufacturing Technology, Vol. 14, 780-783, December 1991. 

The cofiring process is a characteristic process in which materials suited to LTCCs are selected and this can be thought of as the key to deciding the product form of the LTCC. Here we focus on the cofiring process and the developmental direction of future LTCCs. The overall prospects for the future of LTCCs are covered in Chapter 10. 

Most electricity from biofuels is generated by direct combustion. Wood fuels are burned in stoker boilers, and mill waste lignin is combusted in special burners. Plants are generally small, being less than 50 MW in capacity. There is considerable interest in combustion of biomass in a process called cofiring, when biomass is added to traditional fuels for electricity production. Cofiring is usually done by adding biomass to coal, but biomass also can be cofired with... 

Biomass sequestration, which has been embraced by coal companies as the least expensive way to start carbon management, relies on capture from air. Cofiring with biomass followed by sequestration also would lead to a net C02 reduction in the atmosphere (Keith, 2001). On a per ton basis, this option is quite cost effective, but the amount of land area that would be required is extremely large to be practical. Consequently, it is worthwhile to consider other options. Currently, studies that consider capture of C02 directly from the air by chemical means are under way. These processes will require good chemical sorbents that do not pose any environmental concerns in their own right and can be regenerated cost effectively. 

Figure 13. Process flow for cofired multilayer ceramic packages. (Used by courtesy of Interamics.)...

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