Wafer support system and method for separating support substrate from solid-phase bonded wafer and method for manufacturing semiconductor device
A method is disclosed for separating a support substrate from a solid-phase bonded wafer which includes a Si wafer and support substrate solid-phase bonded to back surface of the Si wafer. The method includes a step of irradiating the Si wafer with laser light with a wavelength which passes through the Si wafer and is focused on a solid-phase bonding interface between the Si wafer and support substrate to form a breaking layer in at least part of an outer circumferential portion of the solid-phase bonding interface, a step of separating the breaking layer; and a step of separating the solid-phase bonding interface. The method is capable of using a Si thin wafer without substantial wafer cracking at an initial stage where the wafer is inputted to a wafer process, capable of separating a support substrate from the Si thin wafer easily, and capable of reducing the wafer cost.
1. A method for separating a support substrate from a solid-phase bonded wafer which includes a Si wafer and the support substrate solid-phase bonded to a back surface of the Si wafer, the method comprising at least:
a breaking layer forming step of irradiating the Si wafer with laser light which uses light with a wavelength which can pass through the Si wafer and which is focused on a solid-phase bonding interface between the Si wafer and the support substrate so as to form a breaking layer in at least a part of an outer circumferential portion of the solid-phase bonding interface;
a breaking layer separating step of separating the breaking layer; and
a bonding interface separating step of separating the solid-phase bonding interface.
2. A method for separating a support substrate from the solid-phase bonded wafer according to claim 1 , wherein voids are provided in the solid-phase bonding interface between the Si wafer and the support substrate.
3. A method for separating a support substrate from the solid-phase bonded wafer according to claim 1 , wherein an oxide film is provided in the solid-phase bonding interface between the Si wafer and the support substrate.
4. A method for separating a support substrate from the solid-phase bonded wafer according to claim 1 , wherein the laser light is applied from a side surface of the solid-phase bonded wafer.
5. A method for separating a support substrate from the solid-phase bonded wafer according to claim 1 , wherein the laser light is applied in a direction perpendicular to a surface of the solid-phase bonded wafer.
6. A method for separating a support substrate from the solid-phase bonded wafer according to claim 1 , wherein the support substrate is a substrate selected from the group consisting of a Si wafer, a Si wafer having a SiO layer in a front surface thereof, and a SiC wafer.
7. A method for separating a support substrate from the solid-phase bonded wafer according to claim 1 , wherein the thickness of the Si wafer is less than 300 μm with a diameter of 6 inches, or less than 400 μm with a diameter of 8 inches.
8. A method for manufacturing a semiconductor device, comprising at least:
a solid-phase bonding step of solid-phase bonding a support substrate to a back surface of a Si wafer;
a functional structure forming step of forming a functional structure in a front surface of the Si wafer;
a breaking layer forming step of irradiating the Si wafer with laser light which uses light with a wavelength which can pass through the Si wafer and which is focused on a solid-phase bonding interface between the Si wafer and the support substrate so as to form a breaking layer in at least a part of an outer circumferential portion of the solid-phase bonding interface;
a breaking layer separating step of separating the breaking layer;
a bonding interface separating step of separating the solid-phase bonding interface; and
a back surface processing step of performing back surface processing on the back surface of the Si wafer after the bonding interface separating step.
9. The method for manufacturing a semiconductor device according to claim 8 , wherein voids are provided in the solid-phase bonding interface between the Si wafer and the support substrate.
10. The method for manufacturing a semiconductor device according to claim 8 , wherein an oxide film is provided in the solid-phase bonding interface between the Si wafer and the support substrate.
11. The method for manufacturing a semiconductor device according to claim 8 , wherein the laser light is applied from a side surface of the solid-phase bonded wafer.
12. The method for manufacturing a semiconductor device according to claim 8 , wherein the laser light is applied in a direction perpendicular to a surface of the solid-phase bonded wafer.
13. The method for manufacturing a semiconductor device according to claim 8 , wherein the support substrate is a substrate selected from the group consisting of a Si wafer, a Si wafer having a SiO layer in a front surface thereof, and a SiC wafer.
14. The method for manufacturing a semiconductor device according to claim 8 , wherein the thickness of the Si wafer is less than 300 μm with a diameter of 6 inches, or less than 400 μm with a diameter of 8 inches.