Methods of forming metal ion barrier layers and resulting structures
View Patent ↗A first bond pad of a first device and a second bond pad of a second device are implanted with metal ions. The first and second semiconductor device are bonded together using a direct metal-to-metal bond and an overlay offset occurs between the bond pads such that a portion of the first bond pad and a portion of the second bond pad overlaps and contacts a dielectric material layer. During the bonding process, however, diffusion of the metal ions provides a barrier layer at the interface of the bond pads and the dielectric layers.
1 . A method comprising:
implanting first metal ions in a first conductive material of a first bond pad of a first semiconductor device or second metal ions in a second conductive material of a second bond pad of a second semiconductor device;
aligning the second bond pad to the first bond pad, the alignment having an overlay offset that causes an edge of the second bond pad to overlap a first dielectric layer that surrounds the first bond pad, wherein a first interface is formed between the second bond pad and the first dielectric layer; and
performing a solder-free direct metal-to-metal bonding process to interdiffuse the first conductive material with the second conductive material, the bonding process causing diffusion of the first metal ions or the second metal ions to the first interface and forming a first metal oxide of the first metal ions or the second metal ions at the first interface.
2 . The method of claim 1 , further comprising: implanting the first metal ions, wherein the bonding process further causes diffusion of the first metal ions to outer sidewalls of the first bond pad to form a second diffusion barrier at the outer sidewalls of the first bond pad, wherein the second diffusion barrier is surrounded by a first diffusion barrier.
3 . The method of claim 1 , wherein the overlay offset further causes an edge of the first bond pad to overlap a second dielectric layer that surrounds the second bond pad, wherein a second interface is formed between the first bond pad and the second dielectric layer, wherein the bonding process further causes diffusion of the first metal ions or the second metal ions to the second interface and form a second metal oxide at the second interface.
4 . The method of claim 3 , wherein the first metal oxide is thicker than the second metal oxide.
5 . The method of claim 3 , further comprising: implanting the first metal ions and the second metal ions, wherein the first metal oxide and the second metal oxide have the same thickness.
6 . The method of claim 3 , further comprising: implanting the first metal ions and the second metal ions, wherein a species of the first metal ions is different than a species of the second metal ions, wherein the first metal oxide is a different material than the second metal oxide.
7 . The method of claim 3 , further comprising: implanting the first metal ions to a first concentration and the second metal ions to a second concentration different than the first concentration, wherein the first metal oxide is thicker than the second metal oxide.
8 . The method of claim 1 , wherein a species of the first metal ions or the second metal ions is one of tantalum, titanium, manganese, cobalt, iron, tin, or germanium.
9 . The method of claim 1 , further comprising:
diffusing the first metal ions or the second metal ions to a respective outer surface of the first bond pad or the second bond pad to form a barrier layer surrounding the first conductive material or the second conductive material, respectively.
10 . A device comprising:
a first semiconductor device comprising a first bond pad, a first barrier layer surrounding the first bond pad, and a first dielectric layer surrounding the first barrier layer, wherein the first bond pad includes a first metal ion barrier layer surrounding a conductive material; and
a second semiconductor device comprising a second bond pad, a second barrier layer surrounding the second bond pad, and a second dielectric layer surrounding the second barrier layer, wherein the second bond pad is directly bonded with the first bond pad, wherein a first portion of the second bond pad extends beyond an edge of the first bond pad and overlaps the first dielectric layer, and wherein a first metal oxide is disposed on the first portion of the second bond pad.
11 . The device of claim 10 further comprising metal ions disposed in the conductive material of the first bond pad, the metal ions and the first metal ion barrier layer comprising a same metal element.
12 . The device of claim 10 , wherein the second bond pad further comprises a second metal ion barrier layer surrounding a conductive material, and wherein the first metal oxide is an oxide of the second metal ion barrier layer.
13 . The device of claim 10 , wherein a first portion of the first bond pad extends beyond an edge of the second bond pad and overlaps the second dielectric layer, wherein the first metal ion barrier layer comprises a second metal oxide on the first portion of the first bond pad.
14 . The device of claim 13 , wherein thicknesses of the first metal oxide and the second metal oxide are different.
15 . The device of claim 10 , wherein the first dielectric layer is directly bonded to the second dielectric layer.
16 . A device, comprising:
a first insulating bonding layer;
a first bond pad in the first insulating bonding layer, the first bond pad comprises a first metal ion barrier layer, the first metal ion barrier layer comprising a first metal oxide at a surface of the first bond pad;
a second insulating bonding layer contacting the first insulating bonding layer and the first metal oxide; and
a second bond pad in the second insulating bonding layer and contacting the first bond pad, the second bond pad comprises a second metal ion barrier layer, the second metal ion barrier layer comprising a second metal oxide at a surface of the second bond pad, the second metal oxide contacting the first insulating bonding layer.
17 . The device of claim 16 , wherein a material composition of the first metal oxide is the same as a material composition of the second metal oxide.
18 . The device of claim 16 , wherein a material composition of the first metal oxide is different from a material composition of the second metal oxide.
19 . The device of claim 16 , wherein a thickness of the first metal oxide is different from a thickness of the second metal oxide.
20 . The device of claim 16 , wherein a thickness of the first metal oxide is the same as a thickness of the second metal oxide.