Structured microchannel cooling technology by utilizing a novel hard mask pattern transfer fabrication process
Improved microchannel structures are provided using monolithic structures having deep features (≥150 um) and two or more different feature heights above the substrate. Exemplary channel structures that are enabled by this approach include step-tapered V-groove channels, channels having various kinds of lithographically define roughness, and channels having an arbitrarily defined depth along their length.
1 . A microchannel structure comprising:
a monolithically microfabricated array of channel features, wherein the monolithically microfabricated array of channel features includes a silicon substrate and silicon features having two or more different vertical feature heights above the substrate;
wherein the monolithically microfabricated array of channel features does not include any wafer-to-wafer bonds;
wherein the two or more different vertical feature heights include at least one vertical feature height of 150 microns or more;
wherein the monolithically microfabricated array of channel features includes at least one channel having a bottom channel surface with a nonuniform vertical height that varies along a length of the at least one channel.
2 . The microchannel structure of claim 1 , wherein the microchannel structure includes one or more fluid flow structures selected from the group consisting of: channels, pockets, particle traps, vapor vents, and sensor conduits.
3 . The microchannel structure of claim 1 , wherein the microchannel structure includes two or more primary channels connected via secondary channels.
4 . The microchannel structure of claim 1 , wherein at least one channel of the microchannel structure has stepwise tapered side walls.
5 . The microchannel structure of claim 1 , wherein at least one channel of the microchannel structure has a channel depth that varies along its length.
6 . The microchannel structure of claim 1 , wherein the microchannel structure includes lithographically defined surface roughness.
7 . The microchannel structure of claim 6 , wherein the lithographically defined surface roughness is present at two or more vertical levels of the microchannel structure.
8 . The microchannel structure of claim 6 , wherein the lithographically defined surface roughness includes pillars.
9 . The microchannel structure of claim 6 , wherein the lithographically defined surface roughness includes holes.
10 . The microchannel structure of claim 6 , wherein the lithographically defined surface roughness includes multi-level features.
11 . The microchannel structure of claim 6 , wherein the lithographically defined surface roughness features are configured as an array of surface roughness features having two or more vertical heights above a base surface of the surface roughness features.
12 . An active cooling heat sink device including the microchannel structure of claim 1 .