Photodissociation frame window, systems including a photodissociation frame window, and methods of using a photodissociation frame window

1. A method for cleaning mesa sidewalls of a template, wherein the template has a pattern area on a first surface of a mesa, the mesa sidewalls surround the mesa, and a recessed surface surrounds the mesa sidewalls, the method comprising:

holding the template;

forming a first gap between a photodissociation frame window and the template; and

wherein the photodissociation frame window comprises:

a central region; and

a window region surrounding the central region;

wherein transmittance of photodissociation radiation by the central region is less than the damage threshold; and

wherein transmittance of the photodissociation radiation by the window region is greater than a reaction threshold;

wherein the first gap is bounded by: the mesa sidewalls; the recessed surface; and the window region of the photodissociation frame window;

sending the photodissociation radiation through the window region to expose a portion of the first gap adjacent to the mesa sidewalls to the photodissociation radiation;

wherein material on the mesa sidewalls is removed from the mesa sidewalls by exposing the portion of the first gap adjacent to the mesa sidewalls to the photodissociation radiation.

2. The method according to claim 1 , the positioning system is further configured to position the template relative to the photodissociation frame window such that:

a second gap between the central region and the pattern area of the mesa is formed and further comprises sending a protective gas into the second gap.

3. The method according to claim 2 , further comprising:

sending the photodissociation radiation through the window region to expose a precursor gas in the first gap only after the protective gas is supplied to the second gap.

4. The method according to claim 1 , further comprising:

stop sending the photodissociation radiation through the window region;

after the photodissociation radiation is no longer sent through the window region, removing gas in the first gap using one or both of:

drawing gas from the first gap using vacuum; and

supplying a purging gas to the first gap;

moving the template farther away from the photodissociation frame window, after the gas in the first gap has started being removed from the first gap.

5. The method according to claim 1 , wherein the photodissociation frame window further comprises a frame region surrounding the window region;

wherein transmittance of the photodissociation radiation by the frame region is less than the damage threshold;

wherein the first gap is also bounded by the frame region.