Integrated circuit stack

1. An integrated circuit stack, comprising a plurality of integrated circuit layers comprising at least a first circuit layer electrically connected to a second circuit layer, the first circuit layer having at least one first area of higher heat generation and at least one second area of lower heat generation, and at least one cooling layer arranged in a space between the first and the second circuit layer, the cooling layer comprising at least one fluid inlet and at least one fluid outlet and a hollow space hydraulically connecting the fluid inlet and the fluid outlet for cooling at least the first circuit layer using a cooling fluid, wherein the at least one cooling layer comprises a means for creating a non-uniform flow pattern for the cooling fluid in the hollow space resulting in a higher heat transfer in the first area than in the second area of the first circuit layer.

2. The integrated circuit stack according to claim 1 , wherein the at least one cooling layer comprises at least one guide element directing at least part of the cooling fluid towards the first area.

3. The integrated circuit stack according to claim 2 , wherein the at least one guide element is adapted for creating at least a first flow passing the first area having a higher mass flow rate than a second flow passing the second area.

4. The integrated circuit stack according to claim 2 , wherein the at least one guide element comprises a funnel structure having a first opening towards the fluid inlet and a second opening towards the first area, the first opening being larger than the second opening.

5. The integrated circuit stack according to claim 1 , wherein the at least one cooling layer comprises a channel structure having a first width in the first area and a second width in the second area, the first width being smaller than the second width.

6. The integrated circuit stack according to claim 5 , wherein the width of the channel structure is reduced along at least one path from the fluid inlet to the fluid outlet.

7. The integrated circuit stack according to claim 1 , wherein the at least one cooling layer comprises a grid structure having a lower density in the first area than in the second area.

8. The integrated circuit stack according to claim 1 , wherein the at least one cooling layer comprises a grid structure having grid elements, at least one first grid element arranged in the first area having a larger cross-section than a second grid-element arranged in the second area.

9. The integrated circuit stack according to claim 7 , wherein the grid structure comprises electrical connections between the first and second circuit layer.

10. The integrated circuit stack according to claim 1 , wherein the at least one cooling layer comprises a first surface at the first circuit layer and a second surface at the second circuit layer, the first and second surface having a smaller distance between each other in the first area than in the second area.

11. The integrated circuit stack according to claim 10 , wherein the distance between the first and the second surface is reduced along at least one path from the fluid inlet to the fluid outlet.

12. The integrated circuit stack according to claim 1 , wherein the fluid inlet is placed closer to the first area than to the second area.

13. The integrated circuit stack according to claim 1 , wherein the fluid outlet is placed closer to the second area than to the first area.

14. The integrated circuit stack according to claim 1 , wherein the fluid inlet and the fluid outlet are arranged in proximity to a common corner of the cooling layer and the first area is arranged closer to the common corner than the second area.

15. The integrated circuit stack according to claim 1 , wherein the cooling layer comprises at least two fluid inlets or at least two fluid outlets such that a first flow from the first inlet to the first outlet passing the first area is shorter than a second flow from the second fluid inlet to the first fluid outlet or from the first fluid inlet to the second fluid outlet, respectively.

16. The integrated circuit stack according to claim 1 , wherein the cooling layer has a rectangular shape having four sides, a first and a third side being parallel to each other and a second and a fourth side being parallel to each other, the first and the third side being orthogonal to the second and the fourth side, the cooling layer comprising two fluid inlets and two fluid outlets arranged on the four sides.

17. The integrated circuit stack according to claim 16 , wherein two fluid inlets are arranged on the first and the third side and two fluid outlets are arranged on the second and the fourth side.

18. The integrated circuit stack according to claim 16 , wherein two fluid inlets are arranged on the first and the second side and two fluid outlets are arranged on the third and the fourth side.

19. The integrated circuit stack according to claim 1 , comprising at least a first and a second cooling layers arranged above and below at least one common circuit layer, wherein a flow of the cooling fluid in the first cooling layer is directed in a first direction and a flow of the cooling fluid in the second cooling layer is directed in a second direction, being different from the first direction.

20. The integrated circuit stack according to claim 19 , comprising at least a plurality of cooling layers, wherein a flow of the cooling fluid in alternating cooling layers is directed in opposite directions.