Method and apparatus for depositing films
View Patent ↗In a sputtering apparatus, target particles to be deposited onto a substrate are selectively ionized relative to other particles in the deposition chamber. For example, titanium or titanium-containing target particles are selectively ionized, while inert particles, such as argon atoms, remain substantially unaffected. Advantageously, one or more optical ionizers, such as lasers, are used to create one or more ionization zones within the deposition chamber in which such selective ionization takes place.
1. An apparatus for depositing film on a substrate, the apparatus comprising:
a deposition chamber adapted to hold target particles and other particles;
an ionizer adapted to create an ionization zone to selectively ionize the target particles passing through the ionization zone while leaving the other particles passing through the ionization zone substantially unaffected; and
an electrostatic collimator adapted to electrically steer the ionized target particles through the electrostatic collimator and toward the substrate.
2. The apparatus, as set forth in claim 1 , wherein the deposition chamber comprises a support for holding a source of the target particles.
3. The apparatus, as set forth in claim 1 , wherein the deposition chamber comprises a support for holding the substrate.
4. The apparatus, as set forth in claim 3 , wherein the substrate comprises a semiconductor wafer.
5. The apparatus, as set forth in claim 1 , comprising:
a plasma generator creating a plasma within the deposition chamber to initially ionize the target particles.
6. The apparatus, as set forth in claim 5 , wherein the ionization zone is separated from the plasma by a recombination zone in which the initially ionized target particles de-ionize prior to being re-ionized in the ionization zone.
7. The apparatus, as set forth in claim 1 , wherein the ionizer comprises a laser having a wavelength and power chosen to ionize the target particles in preference to the other particles.
8. The apparatus, as set forth in claim 7 , wherein the laser comprises one of an excimer laser and an EUV laser.
9. The apparatus, as set forth in claim 1 , wherein the target particles comprise titanium-containing particles.
10. The apparatus, as set forth in claim 1 , comprising:
a static field generator creating an static field within the deposition chamber to accelerate the ionized target particles along a given trajectory toward the substrate.
11. The apparatus, as set forth in claim 1 , wherein the deposition chamber comprises a mirrored inner surface.
12. The apparatus, as set forth in claim 11 , wherein the ionizer comprises a laser arranged to direct optical energy onto the mirrored inner surface of the deposition chamber, the mirrored inner surface creating a plane of optical energy.
13. The apparatus, as set forth in claim 1 , wherein the ionizer comprises a plasma generator.
14. The apparatus, as set forth in claim 1 , wherein the ionizer comprises a microwave generator.
15. The apparatus, as set forth in claim 1 , wherein the target particles comprise a refractory metal.
16. The apparatus, as set forth in claim 1 , comprising at least one secondary ionizer adapted to create at least one secondary ionization zone, the at least one secondary ionizer adapted to promote ionization of the target particles as the target particles pass through the at least one secondary ionization zone while leaving the other particles substantially unaffected as the other particles pass through the at least one secondary ionization zone.
17. The apparatus, as set forth in claim 1 , wherein the electrostatic collimator comprises:
a first conductive grid;
a first DC voltage source having a polarity matching that of the ionized target particles coupled to the first conductive grid;
a second conductive grid placed adjacent the first conductive grid; and
a second DC voltage source having a polarity opposite that of the ionized target particles coupled to the second conductive grid.
18. An apparatus for depositing a film on a substrate, the apparatus comprising:
a deposition chamber adapted to contain inert particles, target particles, and a substrate, wherein the target particles comprise titanium-containing particles;
a plurality of ionizers creating a plurality of ionization zones within the deposition chamber, each of the plurality of ionizers ionizing the target particles as they pass through each of the respective ionization zones while leaving the inert particles substantially unaffected; and
a field generator creating a field within the deposition chamber to accelerate the ionized target particles generally along a given trajectory to the substrate.
19. The apparatus, as set forth in claim 18 , wherein the deposition chamber comprises a support for holding a source of the target particles.
20. The apparatus, as set forth in claim 18 , wherein the deposition chamber comprises a support for holding the substrate.
21. The apparatus, as set forth in claim 18 , wherein the substrate comprises a semiconductor wafer.
22. The apparatus, as set forth in claim 18 , wherein the deposition chamber comprises a port for entry of the inert particles.
23. The apparatus, as set forth in claim 18 , comprising:
a plasma generator creating a plasma within the deposition chamber to initially ionize the target particles.
24. The apparatus, as set forth in claim 23 , wherein the plurality of ionization zones are separated from the plasma by a recombination zone in which the initially ionized target particles de-ionize prior to being re-ionized in the plurality of ionization zones.
25. The apparatus, as set forth in claim 18 , wherein each of the plurality of ionizers comprises:
an optical ionizer adapted to create a plane of optical energy within the deposition chamber, the optical energy selectively ionizing the target particles passing through the plane while leaving the inert particles passing through the plane substantially unaffected.
26. The apparatus, as set forth in claim 18 , wherein each of the plurality of ionizers comprises a laser having a wavelength and power chosen to ionize the target particles in preference to the inert particles.
27. The apparatus, as set forth in claim 26 , wherein the laser comprises one of an excimer laser and an EUV laser.
28. The apparatus, as set forth in claim 18 , wherein the target particles comprise a refractory metal.
29. The apparatus, as set forth in claim 18 , wherein the field generator comprises:
an electrostatic field generator adapted to create an electrostatic field to accelerate the ionized target particles along a substantially collimated trajectory toward the substrate.
30. The apparatus, as set forth in claim 18 , wherein the field generator comprises:
a magnetic field generator adapted to create a magnetic field to accelerate the ionized target particles along a substantially collimated trajectory toward the substrate.
31. The apparatus, as set forth in claim 18 wherein each of the plurality of ionizers comprises a plasma generator.
32. The apparatus, as set forth in claim 18 , wherein each of the plurality of ionizers comprises a microwave generator.
33. The apparatus, as set forth in claim 18 , comprising an electrostatic collimator adapted to electrically steer the ionized target particles toward the substrate.
34. The apparatus, as set forth in claim 33 , wherein the electrostatic collimator comprises:
a first conductive grid;
a first DC voltage source having a polarity matching that of the ionized target particles coupled to the first conductive grid;
a second conductive grid placed adjacent the first conductive grid; and
a second DC voltage source having a polarity opposite that of the ionized target particles coupled to the second conductive grid.
35. A method of manufacturing an integrate circuit, comprising the acts of:
passing target particles and inert particles through at least one ionization zone in a deposition chamber to ionize the target particles while leaving the inert particles substantially unaffected; and
steering the ionized target particles into a collimated stream directed along a given path toward the substrate using an electrostatic collimator.
36. The method, as set forth in claim 35 , wherein the act of steering comprises the acts of:
using a first grid of the electrostatic collimator to attract the ionized target particles; and
using a second grid of the electrostatic collimator to direct the ionized target particles through the electrostatic collimator.
37. The method, as set forth in claim 35 , wherein the act of steering comprises the act of charging the substrate to attract the ionized target particles passing through the electrostatic collimator.
38. The method, as set forth in claim 35 , wherein the act of passing comprises the act of passing target particles comprising a refractory metal through the at least one ionization zone.
39. The method, as set forth in claim 35 , wherein the act of passing comprises the act of passing target particles comprising titanium-containing particles through the at least one ionization zone.
40. The method, as set forth in claim 35 , wherein the act of passing comprises the act of passing the target particles and the inert particles through a plurality of ionization zones.