Stress control method for physical vapor deposition of aluminum
Provided are methods of reducing the stress of a semiconductor wafer. The method includes exposing depositing an aluminum layer on a top surface of a substrate; and cooling the substrate to a temperature of less than or equal to 20° C., or less than or equal to 10° C., or less than or equal to 0° C., or less than or equal to −20° C. In some embodiments, the method is conducted within a processing tool, e.g., a cluster tool.
1 . A method of manufacturing a semiconductor device, the method comprising:
cooling a substrate under vacuum to a temperature in a range of from 50° C. to 150° C. to form a cooled substrate;
subsequently depositing an aluminum layer directly on a top surface of the cooled substrate to form a substrate having an aluminum layer directly thereon, the aluminum layer having a thickness in a range of from 1 μm to 6 μm; and
subsequently cooling the substrate having the aluminum layer directly thereon under vacuum on a sub-zero cooling pedestal to a temperature less than or equal to −20° C.
2 . The method of claim 1 , further comprising:
prior to cooling the substrate to a temperature in a range of from 50° C. to 150° C., exposing the substrate to a vacuum.
3 . The method of claim 2 , wherein the substrate is exposed to the vacuum at a temperature in a range of from 150° C. to 400° C.
4 . The method of claim 1 , wherein the aluminum layer is deposited at a temperature in a range of from 200° C. to 450° C.
5 . The method of claim 1 , wherein the aluminum layer is deposited by a physical vapor deposition process.
6 . The method of claim 1 , wherein the method is performed in situ in an integrated processing tool without breaking vacuum or without exposure to ambient air.
7 . The method of claim 1 , further comprising warming the substrate having the aluminum layer thereon to room temperature after cooling to less than or equal to −20° C.
8 . A method of reducing stress on a semiconductor substrate, the method comprising:
exposing the semiconductor substrate to a vacuum in a first processing chamber;
cooling the semiconductor substrate in a second processing chamber to a temperature in a range of 50° C. to 150° C. to form a cooled semiconductor substrate;
depositing an aluminum layer directly on a top surface of the cooled semiconductor substrate, the semiconductor substrate in a first deposition chamber to form a semiconductor substrate having an aluminum layer directly thereon, the aluminum layer having a thickness in a range of from 1 μm to 6 μm; and
cooling the semiconductor substrate having the aluminum layer directly thereon in a third processing chamber under vacuum on a sub-zero cooling pedestal to a temperature less than or equal to −20° C.
9 . The method of claim 8 , wherein the first processing chamber has a temperature in a range of from 150° C. to 400° C.
10 . The method of claim 8 , wherein the aluminum layer is deposited at a temperature in a range of from 200° C. to 400° C.
11 . The method of claim 8 , wherein the aluminum layer is deposited by a physical vapor deposition process.
12 . The method of claim 8 , wherein the method is performed in situ in an integrated processing tool without breaking vacuum or without exposure to ambient air.
13 . The method of claim 8 , further comprising warming the semiconductor substrate having the aluminum layer thereon to room temperature.