Systems and methods for treating substrates with cryogenic fluid mixtures
Disclosed herein are systems and methods for treating the surface of a microelectronic substrate, and in particular, relate to an apparatus and method for scanning the microelectronic substrate through a cryogenic fluid mixture used to treat an exposed surface of the microelectronic substrate. The fluid mixture may be expanded through a nozzle to form an aerosol spray or gas cluster jet (GCJ) spray may impinge the microelectronic substrate and remove particles from the microelectronic substrate's surface. In one embodiment, the fluid mixture may be maintained to prevent liquid formation within the fluid mixture prior to passing the fluid mixture through the nozzle. The fluid mixture may include nitrogen, argon, helium, neon, xenon, krypton, carbon dioxide, or any combination thereof.
1. A method for treating a microelectronic substrate, comprising
receiving the microelectronic substrate in a vacuum process chamber comprising a fluid expansion component comprising an inlet and an outlet;
positioning the substrate opposite the fluid expansion component at a distance within 50 mm of the outlet;
supplying, to the fluid expansion component, an incoming fluid or fluid mixture comprising;
a controllable, incoming pressure greater than atmospheric pressure; and
a controllable, incoming temperature that is less than 273K expanding the incoming fluid or fluid mixture into the process chamber through the fluid expansion component such that at least a portion of the expanded fluid or fluid mixture will contact the microelectronic substrate, the process chamber being maintained at a chamber pressure of 35 Torr or less;
adjusting the incoming temperature and/or incoming pressure such that, while treating the microelectronic substrate, the incoming fluid or fluid mixture transitions between a gaseous state comprising less than 1 volume percent of a liquid phase and a liquid/gas state comprising at least 10 weight percent of a liquid phase; and
removing objects from the microelectronic substrate using the portion of the expanded fluid or fluid mixture that contacts the microelectronic substrate.
2. The method of claim 1 , wherein the incoming temperature comprises a value between 70K and 200K.
3. The method of claim 1 , wherein the incoming temperature comprises a value between 70K and 130K.
4. The method of claim 1 , wherein the distance is less than 10 mm.
5. The method of claim 1 , wherein the chamber pressure comprises a magnitude of 5 Torr to 10 Torr.
6. The method of claim 1 , wherein the chamber pressure comprises a magnitude of 3 Torr to 5 Torr.
7. The method of claim 1 , wherein the fluid comprises argon.
8. The method of claim 1 , wherein the fluid consists essentially of argon or nitrogen.
9. The method of claim 1 , wherein the fluid mixture comprises argon and nitrogen.
10. The method of claim 1 , wherein the fluid mixture comprises nitrogen combined with at least one of the following: helium or neon, and with at least one of the following: argon, krypton, xenon, carbon dioxide.
11. The method of claim 1 , wherein the fluid mixture comprises a gas mixture of argon and nitrogen that is combined with at least one of the following: helium or neon, or with at least one of the following: krypton, xenon, or carbon dioxide.
12. The method of claim 1 , wherein the adjusting step comprises transitioning the incoming fluid or fluid mixture from the gaseous state to the liquid/gas state.
13. The method of claim 1 , wherein the adjusting step comprises transitioning the incoming fluid or fluid mixture from the liquid/gas state to the gaseous state.
14. The method of claim 1 , wherein the distance between the outlet and the substrate is less than 10 mm and the chamber pressure is less than 10 Torr.
15. The method of claim 1 , wherein the distance is about 5 mm and the chamber pressure is less than 10 Torr.