Methods and apparatus for vapor processing of micro-device workpieces
CVD, ALD, and other vapor processes used in processing semiconductor workpieces often require volatilizing a liquid or solid precursor. Certain embodiments of the invention provide improved and/or more consistent volatilization rates by moving a reaction vessel. In one exemplary embodiment, a reaction vessel is rotated about a rotation axis which is disposed at an angle with respect to vertical. This deposits a quantity of the reaction precursor on an interior surface of the vessel's sidewall which is exposed to the headspace as the vessel rotates. Other embodiments employ drivers adapted to move the reaction vessel in other manners, such as a pendulum arm to oscillate the vessel along an arcuate path or a mechanical linkage which moves the vessel along an elliptical path.
1. A method of processing a micro-device workpiece in a reaction chamber, comprising:
placing a volume of a volatilizable reaction precursor in an interior of a vessel having a sidewall and a rotation axis disposed at an angle with respect to vertical to define a headspace in the vessel interior above the volume of the reaction precursor;
determining the angle with respect to vertical based on a volatility of the reaction precursor;
rotating the vessel about the rotation axis in a manner that deposits a quantity of the reaction precursor on an interior surface of the sidewall exposed to the headspace and volatilizes the reaction precursor as the vessel rotates;
delivering a carrier gas to the headspace;
delivering a reaction gas from the headspace to the reaction chamber, the reaction gas comprising the carrier gas and the volatilized precursor; and
depositing a reaction product on a surface of the micro-device workpiece, the reaction product being derived, at least in part, from the volatilized precursor.
2. The method of claim 1 wherein determining the angle with respect to vertical comprises increasing the angle to increase the interior surface of the sidewall exposed to the headspace.
3. The method of claim 1 wherein the angle is between about 1° and about 75° with respect to vertical.
4. The method of claim 1 wherein placing a volume of the precursor in the vessel interior comprises placing at least two components in the interior, and wherein rotating the vessel promotes mixing of the components.
5. The method of claim 1 wherein the reaction precursor comprises a liquid and depositing the reaction precursor on the exposed interior surface comprises wetting the interior surface with the liquid.
6. The method of claim 5 wherein wetting the exposed interior surface coats a portion of the exposed interior surface with a film of the liquid.
7. The method of claim 5 wherein the vessel is rotated at a rate selected such that wetting the exposed interior surface coats a portion of the exposed interior surface with a continuous film of the liquid.
8. The method of claim 1 wherein the reaction precursor comprises a particulate solid and depositing the reaction precursor on the exposed interior surface comprises electrostatically attracting solid particles to the exposed interior surface.
9. A method of volatilizing a volatilizable reaction precursor having a volatility in a vessel having an interior and a central rotation axis at an angle with respect to vertical, comprising:
placing a volume of the volatilizable reaction precursor in the vessel interior, leaving a headspace in the vessel interior above the volume of the volatilizable reaction precursor;
determining the angle with respect to vertical based on the volatility of the reaction precursor;
moving the vessel about the central rotation axis to volatilize the reaction precursor; and
extracting from the headspace a reaction gas comprising the volatilized reaction precursor.
10. The method of claim 9 wherein the angle is between about 1° and about 75° with respect to vertical.
11. The method of claim 9 wherein moving the vessel comprising translating the vessel along a path which is transverse to the central axis.
12. The method of claim 11 wherein the vessel is translated along a horizontal path.
13. The method of claim 9 wherein the vessel is moved along an arcuate path.
14. The method of claim 9 wherein the vessel is pivoted about a pivot axis displaced from the vessel to move the vessel along an arcuate path.
15. The method of claim 9 wherein the vessel is moved continuously as the reaction gas is extracted from the headspace.
16. The method of claim 9 wherein the vessel is moved intermittently.
17. The method of claim 9 wherein placing a volume of the precursor in the vessel interior comprises placing at least two components in the interior, and wherein moving the vessel promotes mixing of the components.
18. The method of claim 9 wherein the reaction precursor comprises a liquid and moving the vessel wets an interior surface of the vessel exposed to the headspace with the liquid.
19. The method of claim 18 wherein wetting the exposed interior surface coats a portion of the exposed interior surface with a film of the liquid.
20. The method of claim 18 wherein the vessel is rotated at a rate selected such that wetting the exposed interior surface coats a portion of the exposed interior surface with a continuous film of the liquid.
21. The method of claim 9 wherein the reaction precursor comprises a particulate solid and solid particles of the reaction precursor are attracted to an interior surface of the vessel as the vessel moves.