Micro-fluidic channels having various critical dimensions
Embodiments of the present invention are directed to microchannels having varied critical dimensions for efficient cooling of semiconductor integrated circuit chip packages. In a non-limiting embodiment of the invention, a patterning stack is formed over a substrate. The patterning stack includes a hard mask, an etch transfer layer on the hard mask, and a photoresist on the etch transfer layer. A manifold trench is formed in a first region of the substrate and is recessed below a surface of the etch transfer layer. A microchannel trench is formed in a second region of the substrate to expose the surface of the etch transfer layer. The manifold trench and the microchannel trench are recessed such that the manifold trench extends into the hard mask and the microchannel trench extends into the etch transfer layer. A manifold and a microchannel are formed in the substrate by pattern transfer.
1. A method for forming a semiconductor device, the method comprising:
forming a patterning stack over a substrate, the patterning stack comprising a hard mask, an etch transfer layer on the hard mask, and a photoresist on the etch transfer layer;
forming a manifold trench in a first region of the substrate, the manifold trench recessed below a topmost surface of the etch transfer layer;
forming a microchannel trench in a second region of the substrate by removing a portion of the photoresist layer to expose the topmost surface of the etch transfer layer;
recessing the manifold trench and the microchannel trench such that the manifold trench punches through the etch transfer layer and recesses a topmost surface of the hard mask and the microchannel trench recesses the topmost surface of the etch transfer layer; and
forming a manifold and a microchannel in the substrate.
2. The method of claim 1 , wherein forming the manifold and the microchannel comprises a pattern transfer of the manifold trench and the microchannel trench into the substrate.
3. The method of claim 1 , wherein the manifold trench and the microchannel trench are recessed concurrently during a same etch process.
4. The method of claim 1 further comprising, after recessing the microchannel trench into the etch transfer layer, forming a second microchannel trench in a third region of the substrate.
5. The method of claim 4 further comprising recessing the manifold trench, the microchannel trench, and the second microchannel trench such that the microchannel trench extends into the etch transfer layer to a first depth and the second microchannel extends into the etch transfer layer to a second depth less than the first depth.
6. The method of claim 5 , wherein a width of the microchannel trench is greater than a width of the second microchannel trench.
7. The method of claim 5 , wherein a width of the microchannel trench is less than a width of the second microchannel trench.
8. The method of claim 1 , wherein the hard mask comprises a nitride and the etch transfer layer comprises an oxide.
9. The method of claim 8 , wherein the oxide is selected to ensure that the etch transfer layer etches at a faster rate than the hard mask when recessing the manifold trench and the microchannel trench.
10. A method for forming a semiconductor device, the method comprising:
forming a patterning stack over a substrate, the patterning stack comprising a hard mask, an etch transfer layer on the hard mask, and a photoresist on the etch transfer layer;
forming a manifold trench in a first region of the substrate, the manifold trench recessed below a topmost surface of the hard mask;
forming a microchannel trench in a second region of the substrate by removing a portion of the photoresist layer to expose a topmost surface of the etch transfer layer;
recessing the manifold trench and the microchannel trench such that the manifold trench extends further into the hard mask and the microchannel trench punches through the etch transfer layer and exposes the topmost surface of the hard mask; and
forming a manifold and a microchannel in the substrate.
11. The method of claim 10 , wherein forming the manifold and the microchannel comprises a pattern transfer of the manifold trench and the microchannel trench into the substrate.
12. The method of claim 10 , wherein the manifold trench and the microchannel trench are recessed concurrently during a same etch process.
13. The method of claim 10 further comprising, after recessing the microchannel trench to expose a surface of the hard mask, forming a second microchannel trench in a third region of the substrate, the second microchannel trench exposing a surface of the etch transfer layer.
14. The method of claim 13 , wherein a width of the microchannel trench is greater than a width of the second microchannel trench.
15. The method of claim 13 , wherein a width of the microchannel trench is less than a width of the second microchannel trench.
16. The method of claim 10 , wherein the hard mask comprises a nitride and the etch transfer layer comprises an oxide.
17. The method of claim 16 , wherein the oxide is selected to ensure that the etch transfer layer etches at a faster rate than the hard mask when recessing the manifold trench and the microchannel trench.