Elimination of Freon and methylchloroform from the manufacturing process for hybrid microelectronic circuits

Recognizing the harmful effects of Freon and methylchloroform solvents on the environment, Westinghouse embarked on an extensive elimination/reduction program in connection with the manufacturing of hybrid microelectronic circuits. Experiments were performed in the following five key areas: thick film substrate fabrication, component attachment, substrate mounting, wirebonding, and package sealing. In each area, it was possible to eliminate or to find a suitable alternative to Freon and methylchloroform. The following recommendations are made: (1) Rosstech 119ME should be used for wet and dry thick film paste removal; (2) PF degreaser, acetone, and isopropyl alcohol should be used for removal of leak test grease: and (3) isopropyl alcohol and/or plasma cleaning should be used for all other cleaning operations