Sintered multilayer heat sinks for microelectronic packages and methods for the production thereof

1. A method for fabricating one or more sintered multilayer heat sinks, the method comprising:

forming a first metal particle-containing precursor layer over a first principal surface of a first metal layer, the first metal particle-containing precursor layer containing metal particles having a melt point;

arranging the first metal layer and the first metal particle-containing layer in a stacked relationship with a second metal layer such that the first metal particle-containing precursor layer is disposed between the first and second metal layers; and

sintering the first metal particle-containing layer at a maximum process temperature less than the melt point of the metal particles to produce a sintered bond layer joining the first and second metal layers in a sintered multilayer heat sink.

2. The method of claim 1 wherein the sintered multilayer heat sink remains interconnected with a plurality of additional sintered multilayer heat sinks as a heat sink panel following sintering of the first metal particle-containing layer, and wherein the method further comprises singulating the heat sink panel after sintering to separate the sintered multilayer heat sink from the plurality of additional sintered multilayer heat sinks.

3. The method of claim 1 further comprising selecting the first metal particle-containing precursor layer to contain at least one of the group consisting of silver particles, gold particles, and copper particles.

4. The method of claim 1 further comprising selecting the metal particle-containing precursor layer to contain an organic binder in addition to the metal particles.

5. The method of claim 4 wherein sintering comprise sintering the first metal particle-containing layer under process conditions at which the organic binder decomposes, at least in substantial part, such that the sintered bond layer is essentially free of the organic binder.

6. The method of claim 4 wherein the organic binder comprises an epoxy, and wherein sintering comprises sintering the first metal particle-containing layer under process conditions leaving at least a substantial portion of the epoxy within the sintered bond layer.

7. The method of claim 1 wherein forming comprises applying the first metal particle-containing precursor layer to the first principal surface of the first metal layer utilizing a film transfer process.

8. The method of claim 1 wherein forming comprises dispensing a wet state, flowable first metal particle-containing precursor layer over the first principal surface of the first metal layer to produce the first metal particle-containing precursor layer.

9. A method for fabricating one or more sintered multilayer heat sinks, the method comprising:

forming a first metal particle-containing precursor layer over a first principal surface of a first metal layer, the first metal particle-containing precursor layer containing metal particles having a melt point;

arranging the first metal layer and the first metal particle-containing layer in a stacked relationship with a second metal layer such that the first metal particle-containing precursor layer is disposed between the first and second metal layers;

sintering the first metal particle-containing layer at a maximum process temperature less than the melt point of the metal particles to produce a sintered bond layer joining the first and second metal layers in a sintered multilayer heat sink; and

attaching a microelectronic device to a second principal surface of the first metal layer opposite the first principal surface after sintering the first metal particle-containing layer.

10. The method of claim 1 wherein sintering comprises sintering the first metal particle-containing layer at a maximum process temperature greater than 170 degrees Celsius (° C.) and less than 300° C.

11. The method of claim 1 further comprising attaching a mount pad to the first metal layer, the mount pad having a thermal conductivity greater than the first metal layer.

12. A method for fabricating one or more sintered multilayer heat sinks, the method comprising:

forming a first metal particle-containing precursor layer over a first principal surface of a first metal layer, the first metal particle-containing precursor layer containing metal particles having a melt point;

arranging the first metal layer and the first metal particle-containing layer in a stacked relationship with a second metal layer such that the first metal particle-containing precursor layer is disposed between the first and second metal layers;

sintering the first metal particle-containing layer at a maximum process temperature less than the melt point of the metal particles to produce a sintered bond layer joining the first and second metal layers in a sintered multilayer heat sink; and

attaching a mount pad to the first metal layer, the mount pad having a thermal conductivity greater than the first metal layer by

forming a second metal particle-containing layer at an interface between the mount pad and the first metal layer; and

sintering the second first metal particle-containing layer in conjunction with the first metal particle layer to attach the mount pad to the first metal layer substantially concomitantly with bonding of the first and second metal layers.

13. A method for fabricating one or more sintered multilayer heat sinks, the method comprising:

forming a first metal particle-containing precursor layer over a first principal surface of a first metal layer, the first metal particle-containing precursor layer containing metal particles having a melt point;

arranging the first metal layer and the first metal particle-containing layer in a stacked relationship with a second metal layer such that the first metal particle-containing precursor layer is disposed between the first and second metal layers;

sintering the first metal particle-containing layer at a maximum process temperature less than the melt point of the metal particles to produce a sintered bond layer joining the first and second metal layers in a sintered multilayer heat sink; and

attaching a mount pad to the first metal layer, the mount pad having a thermal conductivity greater than the first metal layer by

positioning the mount pad within an open cavity provided in the first metal layer and exposed at a second principal surface of the first metal layer; and

bonding the mount pad to the first metal level such that a principal surface of the mount pad is substantially coplanar with the second principal surface of the first metal layer.

14. A method for fabricating sintered multilayer heat sinks, the method comprising:

bonding first and second metal sheets in stacked relationship;

attaching an array of mount pads to the first metal sheet prior to, during, or after bonding the first and second metal sheets in stacked relationship, attaching comprising:

providing metal particle-containing precursor layers at interfaces between the array of mounts pads and the first metal sheet, the metal particle-containing precursor layers containing metal particles having a melt point; and

sintering the metal particle-containing layers at a maximum process temperature less than the melt point of the metal particles to transform the metal particle-containing precursor layers into sintered bond layers bonding the mount pads to the first metal sheet; and

singulating the first and second metal sheets to produce a plurality of sintered multilayer heat sinks each containing at least one mount pad.

15. The method of claim 14 wherein the first metal sheet has a first thermal conductivity, and wherein each mount pad in the array of mount pads has a thermal conductivity exceeding the first thermal conductivity.

16. A method for fabricating sintered multilayer heat sinks, the method comprising:

bonding first and second metal sheets in stacked relationship, wherein a plurality of open cavities is provided in the first metal sheet opposite the second metal sheet;

attaching an array of mount pads to the first metal sheet prior to, during, or after bonding the first and second metal sheets in stacked relationship, attaching comprising:

positioning the array of mount pads in the open cavities provided in the first metal sheet,

providing metal particle-containing precursor layers at interfaces between the array of mounts pads and the first metal sheet, the metal particle-containing precursor layers containing metal particles having a melt point, and

sintering the metal particle-containing layers at a maximum process temperature less than the melt point of the metal particles to transform the metal particle-containing precursor layers into sintered bond layers bonding the mount pads to the first metal sheet; and

singulating the first and second metal sheets to produce a plurality of sintered multilayer heat sinks each containing at least one mount pad.

17. A method for fabricating sintered multilayer heat sinks, the method comprising:

bonding first and second metal sheets in stacked relationship by

forming a first metal particle-containing precursor layer between the first and second metal sheets, and

sintering the first metal particle-containing precursor layer to bond the first and second metal sheets;

attaching an array of mount pads to the first metal sheet prior to, during, or after bonding the first and second metal sheets in stacked relationship, attaching comprising:

providing further metal particle-containing precursor layers at interfaces between the array of mounts pads and the first metal sheet, the further metal particle-containing precursor layers containing metal particles having a melt point, and

sintering the further metal particle-containing layers at a maximum process temperature less than the melt point of the metal particles to transform the further metal particle-containing precursor layers into sintered bond layers bonding the mount pads to the first metal sheet; and

singulating the first and second metal sheets to produce a plurality of sintered multilayer heat sinks each containing at least one mount pad.

18. The method of claim 17 further comprising performing a common sintering process to sinter the metal particle-containing layers substantially concurrently with sintering of the further metal particle-containing precursor layer.

19. A sintered multilayer heat sink, comprising:

a first metal layer having a first principal surface and composed of a first metallic material;

a second metal layer having a second principal surface and composed of a second metallic material different than the first metallic material, the second metallic material having a thermal conductivity and a coefficient of thermal expansion less than the first metal layer; and

a sintered bond layer bonding the first principal surface of the first metal layer to the second principal surface of the second metal layer.

20. The sintered multilayer heat sink of claim 19 further comprising a mount pad bonded to the first metal layer opposite the second metal layer, the mount pad having a thermal conductivity greater than the thermal conductivity of the first metal layer.