Abstract: A mechanical assembly is comprised of a heat exchanger for an integrated circuit. In the assembly, a retainer for a liquid has a bottom with an opening thru which the heat exchanger extends such that a face of the heat exchanger is surrounded by the retainer. Also in the assembly, a compliant member forms a seal for the liquid between the heat exchanger and the retainer. This mechanical assembly is useful in fabricating an alloy film on the heat exchanger's face.