A microchannel structure has microchannels formed therein. The microchannels are to transport a coolant and to be proximate to an integrated circuit to transfer heat from the integrated circuit to the coolant. At least one of the microchannels has a length extent and has a first section at a first location along the length extent and a second section at a second location along the length extent. The first section of the microchannel has a first aspect ratio and the second section is divided into at least two sub-channels. Each sub-channel has a respective second aspect ratio that is greater than the first aspect ratio.