Hybrid bonding with selectively formed dielectric material
A method for hybrid bonding a first semiconductor substrate to a second semiconductor substrate includes forming a first plurality of metal pads on a face of the first substrate, forming a second plurality of metal pads on a face of the second substrate, selectively forming a first dielectric layer over a first insulating material of the first substrate, selectively forming a second dielectric layer over a second insulating material of the second substrate, placing the face of the first substrate against the face of the second substrate so that the first dielectric layer contacts the second dielectric layer, and heating the first substrate and the second substrate to bond the first plurality of metal pads to the second plurality of metal pads. The first and second dielectric layers may be formed by an area selective deposition process.
1 . A method for hybrid bonding a first wafer to a second wafer, the method comprising:
forming a first plurality of metal pads on a face of the first wafer;
forming a second plurality of metal pads on a face of the second wafer;
forming a first treatment layer over the first plurality of metal pads;
forming a second treatment layer over the second plurality of metal pads;
selectively forming a first dielectric layer over a first insulating material of the first wafer, wherein the first treatment layer inhibits the first dielectric layer from being formed over the first plurality of metal pads;
selectively forming a second dielectric layer over a second insulating material of the second wafer, wherein the second treatment layer inhibits the second dielectric layer from being formed over the second plurality of metal pads;
removing the first and second treatment layers;
placing the face of the first wafer against the face of the second wafer so that the first dielectric layer contacts the second dielectric layer, wherein the first plurality of metal pads are recessed below the first dielectric layer, and the second plurality of metal pads are recessed below the second dielectric layer; and
heating the first wafer and the second wafer to bond the first plurality of metal pads to the second plurality of metal pads.
2 . The method of claim 1 , wherein the first dielectric layer and the second dielectric layer are formed by an area selective deposition process.
3 . The method of claim 1 , wherein the first and second dielectric layers are capping dielectric materials.
4 . The method of claim 1 , wherein a thickness of each of the first dielectric layer and the second dielectric layer is 5 nm or less.
5 . The method of claim 1 , wherein at least one of the first wafer and the second wafer includes an optical waveguide.
6 . The method of claim 1 , wherein the first wafer and the second wafer include pad-free regions over a plurality of radio-frequency switches of the first wafer.
7 . The method of claim 6 , wherein adjacent metal pads are separated by a space of at least 15 μm in the pad-free regions.
8 . The method of claim 1 , wherein the first plurality of metal pads and the second plurality of metal pads have a first pitch and a second pitch that is higher than the first pitch.
9 . The method of claim 8 , wherein the first pitch is 5 μm or less.
10 . The method of claim 1 , wherein a width of the first plurality of metal pads and the second plurality of metal pads is 5 μm or less.
11 . The method of claim 1 , wherein the first plurality of metal pads and the second plurality of metal pads are copper.
12 . The method of claim 1 , wherein each of the first and second dielectric layers have an Rq of 0.5 nm or less.
13 . The method of claim 1 , wherein the first and second treatment layers are self-assembled monolayers.
14 . A hybrid bonded device formed by:
forming a first plurality of metal pads on a face of a first substrate;
forming a second plurality of metal pads on a face of a second substrate;
forming a first treatment layer over the first plurality of metal pads;
forming a second treatment layer over the second plurality of metal pads;
selectively forming a first dielectric layer over a first insulating material of the first substrate, wherein the first treatment layer inhibits the first dielectric layer from being formed over the first plurality of metal pads;
selectively forming a second dielectric layer over a second insulating material of the second substrate, wherein the second treatment layer inhibits the second dielectric layer from being formed over the second plurality of metal pads;
removing the first and second treatment layers;
placing the face of the first substrate against the face of the second substrate so that the first dielectric layer contacts the second dielectric layer, wherein the first plurality of metal pads are recessed below the first dielectric layer, and the second plurality of metal pads are recessed below the second dielectric layer; and
heating the first substrate and the second substrate to bond the first plurality of metal pads to the second plurality of metal pads,
wherein a thickness of each of the first dielectric layer and the second dielectric layer is 5 nm or less.
15 . A method for hybrid bonding a first semiconductor substrate to a second semiconductor substrate, the method comprising:
forming a first plurality of metal pads on a face of the first substrate;
forming a second plurality of metal pads on a face of the second substrate;
forming a first treatment layer over the first plurality of metal pads;
forming a second treatment layer over the second plurality of metal pads;
selectively forming a first dielectric layer over a first insulating material of the first substrate, wherein the first treatment layer inhibits the first dielectric layer from being formed over the first plurality of metal pads;
selectively forming a second dielectric layer over a second insulating material of the second substrate, wherein the second treatment layer inhibits the second dielectric layer from being formed over the second plurality of metal pads;
removing the first and second treatment layers;
placing the face of the first substrate against the face of the second substrate so that the first dielectric layer contacts the second dielectric layer, wherein the first plurality of metal pads are recessed below the first dielectric layer, and the second plurality of metal pads are recessed below the second dielectric layer; and
heating the first substrate and the second substrate to bond the first plurality of metal pads to the second plurality of metal pads,
wherein the first and second dielectric layers are formed by an area selective deposition process.
16 . The method of claim 15 , wherein a thickness of each of the first dielectric layer and the second dielectric layer is 5 nm or less.
17 . The method of claim 15 , wherein the first plurality of metal pads and the second plurality of metal pads have a first pitch and a second pitch that is higher than the first pitch.
18 . The method of claim 17 , wherein the first pitch is 5 μm or less.
19 . The method of claim 15 , wherein at least one of the first substrate and the second substrate includes an optical waveguide.
20 . The method of claim 15 , wherein the first substrate and the second substrate include pad-free regions over a plurality of radio-frequency switches of the first substrate, and adjacent metal pads are separated by a space of at least 15 μm in the pad-free regions.