Method of retaining a substrate to a wafer chuck
View Patent ↗A method of retaining a substrate to a wafer chuck. The method features accelerating a portion of the substrate toward the wafer chuck, generating a velocity of travel of the substrate toward the wafer chuck, and reducing the velocity before the substrate reaches the wafer chuck. In this manner, the force of impact of the portion with the wafer chuck is greatly reduced, which is believed to reduce the probability that the structural integrity of the substrate, and layers on the substrate and/or the wafer chuck, are damaged.
1. A method of retaining a substrate to a wafer chuck during separation of an imprint lithography template from the substrate, the method comprising:
applying a first pressure at a first portion of the substrate and the wafer chuck and applying a second pressure at a second portion of the substrate and the wafer chuck;
applying a separation force to the imprint lithography template to separate the imprint lithography template from the substrate such that the first portion of the substrate accelerates toward the wafer chuck generating a velocity of travel toward the wafer chuck; and
adjusting the first pressure at the first portion of the substrate while substantially maintaining the second pressure at the second portion of the substrate such that the velocity of travel of the first portion of the substrate toward the wafer chuck is reduced before the first portion of the substrate reaches the wafer chuck.
2. The method as recited in claim 1 wherein applying the separation force to the imprint lithography template to separate the imprint lithography template from the first portion of the substrate further includes storing potential energy in the substrate by separating the first portion of the substrate from the wafer chuck and converting the potential energy into kinetic energy by moving the first portion of the substrate towards the wafer chuck.
3. The method as recited in claim 1 wherein applying the separation force to the imprint lithography template to separate the imprint lithography template from the substrate further includes increasing a distance between the first portion of the substrate and the wafer chuck by applying the separation force and terminating the separation force.
4. The method as recited in claim 1 wherein adjusting the first pressure further includes adjusting the first pressure to a positive pressure applied to a volume defined between the first portion of the substrate and the wafer chuck.
5. The method as recited in claim 1 wherein applying the separation force to the imprint lithography template to separate the imprint lithography template from the substrate further includes increasing a distance between the first portion of the substrate and the wafer chuck by applying the separation force to the substrate and a positive pressure to a volume defined between the first portion and the wafer chuck and terminating separation force and decreasing the pressure in the volume.
6. The method as recited in claim 1 wherein applying the separation force to the imprint lithography template to separate the imprint lithography template from the substrate further includes increasing a distance between the first portion of the substrate and the wafer chuck by applying the separation force to the substrate and a positive pressure to a volume defined between said the portion and said the wafer chuck and terminating the separation force and increasing the pressure in the volume.
7. A method of retaining a substrate to a wafer chuck, the method comprising:
applying a first pressure at a first portion of the substrate and the wafer chuck and applying a second pressure at a second portion of the substrate and the wafer chuck;
storing potential energy in the substrate by separating the first portion of the substrate from the wafer chuck;
converting the potential energy into kinetic energy by moving the first portion of the substrate towards the wafer chuck; and
reducing the kinetic energy before the first portion of the substrate contacts the wafer chuck by adjusting the first pressure between the first portion of the substrate and the wafer chuck while substantially maintaining the second pressure at the second portion of the substrate and the wafer chuck.
8. The method as recited in claim 7 wherein the first portion of substrate decelerates as the first portion of the substrate approaches the wafer chuck.
9. The method as recited in claim 7 wherein storing further includes increasing a distance between the first portion and a region of the wafer chuck in superimposition therewith while maintaining a substantially constant distance between the second portion of the substrate and the wafer chuck.
10. The method as recited in claim 7 wherein storing further includes separating the first portion of the substrate by generating a positive pressure in a volume defined between the first portion and the wafer chuck and subjecting the substrate to a separation force.
11. The method as recited in claim 10 wherein converting the potential energy into kinetic energy by moving the first portion of the substrate towards the wafer chuck further includes terminating the separation force.
12. The method as recited in claim 11 wherein reducing the kinetic energy before the first portion of the substrate contacts the wafer chuck further includes increasing the first pressure in the volume.
13. The method as recited in claim 7 wherein storing potential energy in the substrate by separating the first portion of the substrate from the wafer chuck further includes separating the first portion of the substrate by subjecting the substrate to a separation force and applying a vacuum pressure as the first pressure between the substrate and the wafer chuck to define a deformation vacuum pressure, the deformation vacuum pressure being less than the second pressure applied to the second portion of the substrate.
14. The method as recited in claim 13 wherein converting the potential energy into kinetic energy by moving the first portion of the substrate towards the water chuck further includes terminating the separation force and reducing further includes terminating the deformation vacuum pressure and applying a positive pressure in place thereof.
15. A method of retaining a substrate to a wafer chuck, the method comprising:
storing potential energy in the substrate by separating a first portion of the substrate from the wafer chuck while maintaining a substantially constant distance between a second portion the substrate and the wafer chuck by applying a first pressure between the first portion of the substrate and the wafer chuck and applying a second pressure at the second portion of the substrate and the wafer chuck;
applying a separation force to the imprint lithography template to separate the imprint lithography template from the substrate and converting the potential energy into kinetic energy; and
adjusting the first pressure between the first portion of the substrate and the wafer chuck while substantially maintaining the second pressure at the second portion of the substrate and the wafer chuck to reduce the kinetic energy before the first portion of the substrate contacts the wafer chuck by slowing a velocity of the first portion.
16. The method as recited in claim 15 wherein storing further includes increasing a distance between the first portion and a region of the wafer chuck in superimposition therewith.
17. The method as recited in claim 15 wherein reducing further including increasing the first pressure.
18. The method as recited in claim 15 wherein the first pressure is a vacuum pressure between the substrate and the wafer chuck, defining a deformation vacuum pressure the deformation vacuum pressure being less than the second pressure being applied to the second portion of the substrate and reducing further includes terminating the deformation vacuum pressure and applying a positive pressure in place of the deformation vacuum pressure.