| abstract |
A method is provided for processing an electronic circuit assembly having surface mount integrated circuit packages mounted to its substrate, in which ingress of a conformal coating into a void present between the IC package and the substrate is prevented by a masking composition which forms a barrier around the IC package prior to the conformal coating process. The masking compositions are hot melt materials, in that each is initially a solid at roughly room temperature, melts to become a liquid at an elevated temperature at which the masking composition is applied to the electronic assembly, and forms a solid upon cooling to a temperature corresponding to a service temperature of the electronic assembly. As such, the masking compositions can be rapidly applied through various highly controllable techniques, and will quickly and sufficiently solidify upon cooling to allow handling of the electronic assembly. The masking compositions may be nonreactive, indicating that the barrier can be remelted, or reactive, indicating that a post-application curing process occurs over time at a temperature less than the elevated application temperature. |