Offset pads over TSV
Representative techniques and devices including process steps may be employed to mitigate the potential for delamination of bonded microelectronic substrates due to metal expansion at a bonding interface. For example, a metal pad may be disposed at a bonding surface of at least one of the microelectronic substrates, where the contact pad is positioned offset relative to a TSV in the substrate and electrically coupled to the TSV.
1. A method of forming a microelectronic assembly, comprising:
providing a first through silicon via (TSV) into a first substrate having a first bonding surface, the first TSV extending in a direction normal to the first bonding surface through at least a portion of the first substrate without being exposed at the first bonding surface;
providing a recess in the first bonding surface, aligned with and overlapping the first TSV in a direction normal to the first bonding surface;
providing a first metal contact pad at the first bonding surface, offset relative to the first TSV and not overlapping the first TSV in the direction normal to the first bonding surface, the first metal contact pad electrically coupled to the first TSV with one or more embedded conductive traces; and
bonding the first substrate to a second substrate, the recess adjacent to disposed at a bonding interface between the first and second substrates.
2. The method of forming a microelectronic assembly of claim 1 , wherein the one or more embedded conductive traces are provided as part of a redistribution layer and at least a portion of the redistribution layer is disposed between the first TSV and the recess.
3. The method of forming a microelectronic assembly of claim 1 , further comprising providing the recess in the first bonding surface to have a diameter that is larger by a predetermined amount than a diameter of the first TSV.
4. The method of forming a microelectronic assembly of claim 1 , wherein the recess comprises an expansion region, for expansion of the first TSV during a bonding process.
5. The method of forming a microelectronic assembly of claim 1 , further comprising removing material from the first substrate to expose the first TSV at a side opposite the first bonding surface.
6. The method of forming a microelectronic assembly of claim 1 , further comprising shaping an exposed surface of the first metal contact pad.
7. A method of forming a microelectronic assembly, comprising:
forming a first substrate to have a base layer and an insulating layer over the base layer, the insulating layer having a first bonding surface, a first through silicon via (TSV) extending at least partially through the base layer of the first substrate in a direction normal to the first bonding surface without being exposed at the first bonding surface;
forming a recess in the first bonding surface overlapping the first TSV, the recess comprising an expansion region configured to compensate for thermal expansion of the first TSV during a bonding step;
disposing a first metal contact pad at the first bonding surface, the first metal contact pad offset relative to a location of the first TSV;
electrically coupling the first metal contact pad to the first TSV with one or more embedded conductive traces; and
direct bonding the first substrate to a second substrate using a direct dielectric-to-dielectric, non-adhesive bonding technique at the first bonding surface of the first substrate.
8. The method of forming a microelectronic assembly of claim 7 , further comprising planarizing the first bonding surface to have a predetermined maximum surface variance for direct bonding and the first metal contact pad to have a predetermined recess relative to the first bonding surface.
9. The method of forming a microelectronic assembly of claim 7 , further comprising depositing one or more inorganic dielectric layers on a second surface of the first substrate opposite the insulating layer and planarizing the one or more inorganic dielectric layers to form a second bonding surface having a second predetermined maximum surface variance.
10. The method of forming a microelectronic assembly of claim 9 , further comprising direct bonding the first substrate to a second substrate using a direct dielectric-to-dielectric, non-adhesive bonding technique at the second bonding surface of the first substrate.
11. The method of forming a microelectronic assembly of claim 9 , wherein the depositing comprises depositing a first low temperature insulating layer at the second surface of the first substrate, a second low temperature insulating layer over the first low temperature insulating layer, and a third insulating layer over the second low temperature insulating layer to form the second bonding surface.
12. The method of forming a microelectronic assembly of claim 11 , further comprising:
patterning the second low temperature insulating layer;
etching an opening over the first TSV, the opening extending through the second low temperature insulating layer and partially through the first low temperature insulating layer;
depositing a conductive material within the opening to form a conductive pad electrically coupled to the first TSV; and
forming a recess in or above the conductive material relative to the second bonding layer.
13. The method of forming a microelectronic assembly of claim 12 , further comprising depositing an adhesion/barrier layer onto exposed surfaces of the opening prior to depositing the conductive material within the opening.