Wafer bonding method of system in package
View Patent ↗A method of bonding a wafer in a system in package is provided. A plating layer is formed on each of a first semiconductor substrate and a second semiconductor substrate. The plating layers are then bonded to each other to connect the semiconductor substrates.
1. A method of wafer bonding for a system in package, comprising:
forming a first via hole on a first semiconductor substrate;
forming a first photoresist pattern around the first via hole;
forming a first plating layer on the first via hole, wherein an upper surface of the first plating layer is above an upper limit of the first via hole;
forming a second via hole on a second semiconductor substrate;
forming a second photoresist pattern around the second via hole;
forming a second plating layer on the second via hole, wherein an upper surface of the second plating layer is above an upper limit of the second via hole;
bonding the first plating layer to the second plating layer; and exposing the second via hole on a rear surface of the second semiconductor substrate,
wherein the upper surface of the first plating layer is lower than an upper surface of the first photoresist pattern; and wherein the upper surface of the second plating layer is lower than an upper surface of the second photoresist pattern.
2. The method according to claim 1 , wherein forming the first plating layer comprises:
performing a first electroplating process, and
performing a first planarization process using the first photoresist pattern as an endpoint; and
wherein forming the second plating layer comprises:
performing a second electroplating process, and
performing a second planarization process using the second photoresist pattern as an endpoint.
3. The method according to claim 2 , wherein the first planarization process is chemical mechanical polishing (CMP), and wherein the second planarization process is CMP.
4. The method according to claim 3 , wherein performing the first planarization process comprises over-polishing the first plating layer such that the top surface of the first plating layer is lower than the upper surface of the first photoresist pattern; and
wherein performing the second planarization process comprises over-polishing the second plating layer such that the top surface of the second plating layer is lower than the upper surface of the second photoresist pattern.
5. The method according to claim 1 , wherein bonding the first plating layer to the second plating layer is performed at a pressure of about 1 psi to about 100 psi and at a temperature of about 200° C. to about 500° C. for a period of time of about 1 minute to about 100 minutes.
6. The method according to claim 1 , wherein the first photoresist pattern has a thickness of about 1 μm to about 200 μm, and wherein the second photoresist pattern has a thickness of about 1 μm to about 200 μm.
7. The method according to claim 1 , wherein the first plating layer has a thickness above the first via hole of about 1 μm to about 100 μm, and wherein the second plating layer has a thickness above the second via hole of about 1 μm to about 100 μm.
8. A method of wafer bonding for a system in package, comprising:
forming a first via hole on a first semiconductor substrate;
forming a first photoresist pattern around the first via hole;
forming a first plating layer on the first via hole, wherein an upper surface of the first plating layer is above an upper limit of the first via hole;
forming a second via hole on a second semiconductor substrate;
forming a second photoresist pattern around the second via hole;
forming a second plating layer on the second via hole, wherein an upper surface of the second plating layer is above an upper limit of the second via hole;
bonding the first plating layer to the second plating layer; and exposing the second via hole on a rear surface of the second semiconductor substrate,
forming a first insulating layer on the first via hole;
forming a first barrier metal layer on the first insulating layer;
forming a first seed layer on the first barrier metal layer, wherein the first plating layer is formed using the first seed layer and wherein the first photoresist pattern is formed on the first seed layer;
forming a second insulating layer on the second via hole;
forming a second barrier metal layer on the second insulating layer; and
forming a second seed layer on the second barrier metal layer, wherein the second plating layer is formed using the second seed layer and wherein the second photoresist pattern is formed on the second seed layer.
9. The method according to claim 8 , further comprising:
removing the first photoresist pattern;
etching the first insulating layer, the first barrier metal layer, and the first seed layer using the first plating layer as an etch mask;
removing the second photoresist pattern; and
etching the second insulating layer, the second barrier metal layer, and the second seed layer using the second plating layer as an etch mask.
10. The method according to claim 9 , wherein removing the first photoresist pattern comprises performing a first ashing process; and wherein removing the second photoresist pattern comprises performing a second ashing process.
11. The method according to claim 1 , further comprising:
performing a bake process on the first photoresist pattern; and
performing a bake process on the second photoresist pattern.
12. The method according to claim 11 , wherein the bake process on the first photoresist pattern is performed at a temperature of about 100° C. to about 400° C. for a period of time of about 1 minute to about 100 minutes, and wherein the bake process on the second photoresist pattern is performed at a temperature of about 100° C. to about 400° C. for a period of time of about 1 minute to about 100 minutes.
13. A method of wafer bonding for a system in package, comprising:
forming a first via hole on a first semiconductor substrate;
forming a first photoresist pattern around the first via hole;
forming a first plating layer on the first via hole, wherein an upper surface of the first plating layer is above an upper limit of the first via hole;
forming a second via hole on a second semiconductor substrate;
forming a second photoresist pattern around the second via hole;
forming a second plating layer on the second via hole, wherein an upper surface of the second plating layer is above an upper limit of the second via hole;
bonding the first plating layer to the second plating layer; and exposing the second via hole on a rear surface of the second semiconductor substrate,
wherein exposing the second via hole on a rear surface of the second semiconductor substrate comprises performing a wafer back grinding process.