Water soluble paste systems

The aim is to substitute toxic and ecologically harmful leaning agents in the e lectronic industry (like Pregan Universal 4 or Kiwoclean), which are dangerous for the environment, form a lot of CO2 during the combustion and need a lot of energy for their production. Harmful solvents for the cleaning of screens and devices after screen-printing of electronic circuits can be substituted by water. In comparison to cleaning agents on organic base the application of water is more cost efficient and leads to more safety in use. Hence a development of water soluble paste systems is necessary. The new systems should have comparable properties to commercial available systems (not water soluble). Therefore different polymers and solvents for water soluble and ecological burn out organic vehicles were tested. The properties of the developed pastes were investigated and after characterisation of pastes the new water soluble organic vehicle was selected. The development comprised pastes for AlN (AgPd conductor paste, Ru O2 resistor pastes, encapsulating paste), pastes for LTCC (via-, innerlayer and conductor paste), pastes for SOFC (cathode, anode) and an Active Metal Brazing (AMB) Paste. It could be showed that water soluble pastes with equivalent characteristics to commercial pastes are producible. Cleaning as well as recycling can be made with water.