A chip module heat transfer apparatus includes one or more chips
electronically connected to a module substrate by controlled collapse
chip connection (C4) solder joints. The module substrate, which is
preferably an FR-4 laminate or other organic substrate, has cut-out
channels formed thereon. A permanent solder mask is laminated over the
cut-out channels to form thermal dissipation channels, which are in fluid
communication with input and output ports. The C4 solder joints include
solder balls that electronically connect terminals on the chips to
corresponding attach pads on the substrate that are exposed through the
mask. The thermal dissipation channels extend along rows of attach pads.
A cooling fluid, such as inert perfluorocarbon fluid, flows through the
thermal dissipation channels to remove heat and to mitigate strain on the
solder balls due to coefficient of thermal expansion (CTE) mismatch
between the chips and the substrate.