Selective alteration of interconnect pads for direct bonding
View Patent ↗A bonded structure and a method of forming such a bonded structure are disclosed. The bonded structure can include a first element and a second element. The first element has a first bonding surface including a first nonconductive material and a plurality of first contact pads. The first contact pads are electrically connected to one or more first microelectronic devices in the first element. The second element has a second bonding surface including a second nonconductive material and a plurality of second contact pads. The second contact pads are electrically connected to one or more second microelectronic devices in the second element. The second bonding surface is directly bonded to the first bonding surface without an intervening adhesive to form a bonding interface, and one or more first contact pads is omitted from the first microelectronic element to alter the functionality of the bonded structure.
1 . A bonded structure comprising:
a first element having a first bonding surface comprising a first nonconductive material and a plurality of first contact pads at least partially embedded in the first nonconductive material, the first contact pads electrically connected to one or more first microelectronic devices in the first element; and
a second element having a second bonding surface comprising a second nonconductive material and a plurality of second contact pads at least partially embedded in the second nonconductive material, the second contact pads electrically connected to one or more second microelectronic devices in the second element,
wherein the second bonding surface is directly bonded to the first bonding surface without an intervening adhesive to form a bonding interface,
wherein the first element comprises an omitted contact pad region comprising an insulating material, wherein a trace terminating at the omitted contact pad region extends to at least one of the one or more first microelectronic devices, the trace being electrically isolated from any contact pad.
2 . The bonded structure of claim 1 , wherein the omitted contact pad region comprises one or more voids in the first nonconductive material.
3 . The bonded structure of claim 1 , wherein the insulating material of the omitted contact pad region comprises a solid nonconductive filler material disposed in the first nonconductive material and an interface is disposed between the solid nonconductive filler material and the first nonconductive material.
4 . The bonded structure of claim 1 , wherein the omitted contact pad region comprises a fully-omitted contact pad region devoid of a contact pad.
5 . The bonded structure of claim 4 , wherein the first nonconductive material extends continuously within the omitted contact pad region.
6 . The bonded structure of claim 1 , wherein the omitted contact pad region comprises a partially-omitted contact pad region including a remaining portion of one of the plurality of first contact pads and a void above the remaining portion.
7 . The bonded structure of claim 6 , further comprising a solid nonconductive filling material in the void.
8 . The bonded structure of claim 1 , wherein the plurality of first contact pads is directly bonded to the plurality of second contact pads, the bonded structure comprising a plurality of traces extending between the one or more first microelectronic devices and the plurality of first contact pads.
9 . The bonded structure of claim 1 , wherein the trace has a terminating end that terminates into the omitted contact pad region.
10 . The bonded structure of claim 9 , wherein the first element comprises a bulk semiconductor portion, the first nonconductive material disposed on the bulk semiconductor portion, the terminating end of the trace extending into the first nonconductive material.
11 . The bonded structure of claim 1 , wherein the trace is connected to an electrical ground.
12 . The bonded structure of claim 1 , wherein the second element comprises a second omitted contact pad region, and the second omitted contact pad region is aligned with the omitted contact pad region.
13 . The bonded structure of claim 1 , wherein the plurality of first contact pads is arranged in a regular pattern but for the omitted contact pad region, as seen from a bottom plan view.
14 . The bonded structure of claim 1 , wherein the omitted contact pad region comprises a barrier layer disposed in the first nonconductive material, a rounded or angled surface of the first nonconductive material extending between the barrier layer and the bonding interface.
15 . A bonded structure comprising:
a first element having a first bonding surface comprising a first nonconductive material and a plurality of first contact pads at least partially embedded in the first nonconductive material, the first contact pads electrically connected to one or more first microelectronic devices in the first element by way of one or more traces of a plurality of first traces; and
a second element having a second bonding surface comprising a second nonconductive material and a plurality of second contact pads at least partially embedded in the second nonconductive material, the second contact pads electrically connected to one or more second microelectronic devices in the second element by way of one or more second traces,
wherein the second bonding surface is directly bonded to the first bonding surface without an intervening adhesive to form a bonding interface, and wherein at least one first trace of the plurality of first traces extends between at least one of the one or more first microelectronic devices and an omitted contact pad region at the bonding interface and is at least partially embedded in the first nonconductive material, the omitted contact pad region comprising an insulating material, wherein the at least one first trace terminates at the omitted contact pad region and is electrically isolated from any contact pad.
16 . The bonded structure of claim 15 , wherein the omitted contact pad region comprises one or more voids in the first nonconductive material.
17 . The bonded structure of claim 16 , wherein the insulating material of the omitted contact pad region comprises a solid nonconductive filler material disposed in the one or more voids, an interface disposed between the solid nonconductive filler material and the first nonconductive material.
18 . The bonded structure of claim 15 , wherein the omitted contact pad region comprises a fully-omitted contact pad region devoid of a contact pad.
19 . The bonded structure of claim 18 , wherein the first nonconductive material extends continuously within the omitted contact pad region.
20 . The bonded structure of claim 1 , wherein the trace terminates below the bonding interface.
21 . The bonded structure of claim 15 , wherein the at least one first trace terminates below the bonding interface.