Dicing method for stacked semiconductor devices
A method includes providing first and second wafers; forming a first device layer in a top portion of the first wafer; forming a second device layer in a top portion of the second wafer; forming a first groove in the first device layer; forming a second groove in the second device layer; bonding the first and second wafers together after at least one of the first and second grooves is formed; and dicing the bonded first and second wafers by a cutting process, wherein the cutting process cuts through the first and second grooves.
1. A method, comprising:
providing first and second wafers;
forming a first device layer in a top portion of the first wafer;
forming a second device layer in a top portion of the second wafer;
forming a first groove in the first device layer;
forming a second groove in the second device layer;
bonding the first and second wafers together after at least one of the first and second grooves is formed; and
dicing the bonded first and second wafers by a cutting process, wherein the cutting process cuts through the first and second grooves,
wherein the first groove has a first sidewall, a cut made by the cutting process has a second sidewall, and the first sidewall has a slope smaller than that of the second sidewall.
2. The method of claim 1 , wherein each of the first and second grooves is formed by a laser grooving process.
3. The method of claim 2 , wherein the cutting process includes mechanical dicing with a saw or a blade.
4. The method of claim 1 , wherein, after the bonding, the second groove is directly under the first groove.
5. The method of claim 1 , wherein the first groove extends completely through the first device layer and the second groove extends completely through the second device layer.
6. The method of claim 1 , wherein, after the bonding, a bottom surface of the first wafer directly faces a top surface of the second device layer.
7. The method of claim 6 , wherein the bottom surface of the first wafer includes a first bond pad and the top surface of the second device layer includes a second bond pad, and wherein the bonding physically joins the first bond pad to the second bond pad.
8. The method of claim 6 , further comprising:
forming a through-substrate-via (TSV) in the first wafer prior to the bonding, such that the TSV electrically couples the first device layer to a bond pad at the bottom surface of the first wafer.
9. The method of claim 1 , further comprising:
forming a through-substrate-via (TSV) in the first wafer prior to the bonding, such that the TSV electrically couples the first device layer to the second device layer after the bonding.
10. A method of fabricating a stacked semiconductor device, comprising:
providing a first structure having a first substrate and a first device layer on the first substrate;
providing a second structure having a second substrate and a second device layer on the second substrate;
forming a second groove in the second device layer;
bonding a bottom surface of the first substrate to a top surface of the second device layer;
after the bonding, forming a first groove in the first device layer; and
cutting through the first groove, the first substrate, the second groove, and the second substrate in sequence,
wherein the first groove has a first sidewall, the first substrate has a second sidewall formed by the cutting, and the first sidewall has a surface roughness larger than that of the second sidewall.
11. The method of claim 10 , wherein each of the first and second grooves is formed by a laser grooving process.
12. The method of claim 10 , wherein the cutting includes a mechanical dicing with a saw or a blade.
13. The method of claim 10 , wherein the first groove extends into a top portion of the first substrate and the second groove extends into a top portion of the second substrate.
14. The method of claim 10 , wherein each of the first and second grooves is along a scribing channel.
15. A method of fabricating a stacked semiconductor device, comprising:
providing a first structure having a first substrate and a first device layer on the first substrate;
providing a second structure having a second substrate and a second device layer on the second substrate;
forming a through-substrate-via (TSV) in the first substrate, such that the TSV electrically couples the first device layer to a bond pad at a bottom surface of the first substrate;
forming a second groove in the second device layer;
bonding the bottom surface of the first substrate to a top surface of the second device layer, thereby forming bonded first and second structures;
after the bonding, forming a first groove in the first device layer; and
dicing the bonded first and second structures by a cutting process, wherein the cutting process cuts through the first and second grooves,
wherein the first groove has a first sidewall, the first substrate has a second sidewall made by the cutting process, and the first sidewall has a slope smaller than that of the second sidewall.
16. The method of claim 15 , wherein each of the first and second grooves is along a scribing channel.
17. The method of claim 15 , wherein the first groove extends into a top portion of the first substrate and the second groove extends into a top portion of the second substrate.
18. The method of claim 15 , wherein, after the bonding, the first groove is directly above the second groove.
19. The method of claim 15 , wherein each of the first and second grooves is formed by a laser grooving process, and wherein the cutting process includes a mechanical dicing process.
20. The method of claim 15 , wherein, after the bonding and prior to the dicing, a void remains in the second groove.