Method of processing wafer

Abstract

A method of processing a wafer includes performing a grinding process on the surface of the wafer to reduce the thickness of the wafer, wherein the surface of the wafer has a roughness after the grinding process; measuring the value of the roughness; forming a first metal layer on the surface of the wafer; and performing an annealing process to convert the first metal layer and a portion of the wafer into an alloy layer, wherein the operating energy of the annealing process is determined according to the magnitude of the roughness value.

Claims

1. A method of processing a wafer, comprising: performing a polishing process on a surface of a wafer to reduce a thickness of the wafer, wherein after the polishing process, the surface of the wafer has a roughness; measuring a value of the roughness; forming a first metal layer on the surface of the wafer; and performing an annealing process to convert the first metal layer and a portion of the wafer into an alloy layer, wherein the operating energy of the annealing process is determined according to the magnitude of the roughness value, wherein the operating energy of the annealing process is between 4.2 and 4.6 J / cm² when the roughness value is between 90 nm and 120 nm, or between 5.0 and 5.3 J / cm² when the roughness value is below 80 nm.

2. The method as described in claim 1, wherein when the roughness value is between 90 nanometers and 120 nanometers, the alloy layer is a nickel-silicon layer, and the nickel content in the nickel-silicon layer is greater than the silicon content.

3. The method as described in claim 1, wherein when the roughness value is between 90 nanometers and 120 nanometers, the warpage direction of the wafer after performing the annealing process is the same as the warpage direction of the wafer before performing the annealing process.

4. The method as described in claim 1, wherein when the roughness value is below 80 nanometers, the alloy layer is a nickel-silicon layer, and the nickel content in the nickel-silicon layer is less than the silicon content.

5. The method as described in claim 1, wherein when the roughness value is below 80 nanometers, the warpage direction of the wafer after the annealing process is opposite to the warpage direction of the wafer before the annealing process.

6. The method as described in claim 1 further comprises: forming a second metal layer on the alloy layer.

7. The method as described in claim 6, wherein the degree of warpage of the wafer after the formation of the second metal layer is less than the degree of warpage of the wafer before the formation of the second metal layer.

8. The method as described in claim 1, wherein the annealing process is a laser annealing process.

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