Integrated circuit coolant microchannel with compliant cover

An apparatus comprising:

• a microchannel structure having microchannels formed therein, said microchannels to transport a coolant and to be proximate to an integrated circuit to transfer heat from the integrated circuit to the coolant;
• a membrane positioned on the microchannel structure to define a respective upper wall of each of said microchannels, said membrane presenting a compliant surface to said microchannels;
• and
• a cap member positioned on said microchannel structure with said membrane sandwiched between said cap member and said microchannel structure, said cap member defining a plurality of relief channels each located above a respective one of said microchannels, said membrane forming a bottom wall of each of the relief channels, said relief channels for allowing said membrane to bulge into said relief channels in case said coolant freezes and expands in one or more of said microchannels;
• wherein said membrane is formed of polydimethylsiloxane elastomer.