METHOD AND APPARATUS FOR REMOTE PLASMA TREATMENT FOR REDUCING METAL OXIDES ON A METAL SEED LAYER

• US 20140256128A1
• Filed: 11/21/2013
• Published: 09/11/2014
• Est. Priority Date: 03/06/2013
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Spurlin, Tighe A., Antonelli, George Andrew, Doubina, Natalia, Duncan, James E., Reid, Jonathan D., Porter, David
• Granted Patent: US 9,865,501 B2
• Time in Patent Office: Days
• US Class Current: 438/643
• CPC Class Codes: C23C 18/1619 Apparatus for electroless plating
• CPC Class Codes: C23C 18/1675 Process conditions
• CPC Class Codes: C23C 18/1851 of surfaces of non-metallic or semiconducting in organic material
• CPC Class Codes: C23C 18/1865 Heat
• CPC Class Codes: C23C 18/1868 Radiation, e.g. UV, laser
• CPC Class Codes: C25D 17/001 Apparatus specially adapted for electrolytic coating of wafers, e.g. semiconductors or solar cells
• CPC Class Codes: C25D 5/34 Pretreatment of metallic surfaces to be electroplated
• CPC Class Codes: C25D 5/40 Nickel; Chromium
• CPC Class Codes: C25D 5/42 of light metals
• CPC Class Codes: H01J 37/32357 Generation remote from the workpiece, e.g. down-stream
• CPC Class Codes: H01L 21/02063 the processing being the formation of vias or contact holes
• CPC Class Codes: H01L 21/02068 during, before or after processing of conductive layers, e.g. polysilicon or amorphous silicon layers
• CPC Class Codes: H01L 21/67115 mainly by radiation
• CPC Class Codes: H01L 21/68742 characterised by a lifting arrangement, e.g. lift pins
• CPC Class Codes: H01L 21/76861 Post-treatment or after-treatment not introducing additional chemical elements into the layer
• CPC Class Codes: H01L 21/76873 for electroplating
• CPC Class Codes: H01L 21/76874 for electroless plating

Abstract

Method and apparatus for reducing metal oxide surfaces to modified metal surfaces are disclosed. By exposing a metal oxide surface to a remote plasma, the metal oxide surface on a substrate can be reduced to pure metal and the metal reflowed. A remote plasma apparatus can treat the metal oxide surface as well as cool, load/unload, and move the substrate within a single standalone apparatus. The remote plasma apparatus includes a processing chamber and a controller configured to provide a substrate having a metal seed layer in a processing chamber, form a remote plasma of a reducing gas species where the remote plasma includes radicals, ions, and/or ultraviolet (UV) radiation from the reducing gas species, and expose a metal seed layer of the substrate to the remote plasma to reduce oxide of the metal seed layer to metal and to reflow the metal.

Claims

1. A remote plasma apparatus for treating a substrate with a metal seed layer, the remote plasma apparatus comprising:

a processing chamber;

a substrate support for holding the substrate in the processing chamber;

a remote plasma source over the substrate support;

a showerhead between the remote plasma source and the substrate support; and

a controller with instructions for performing the following operations;

(a) providing the substrate with the metal seed layer in the processing chamber, wherein a portion of the metal seed layer has been converted to oxide of the metal;

(b) forming a remote plasma of a reducing gas species in the remote plasma source, wherein the remote plasma comprises one or more of;

radicals, ions, and ultraviolet (UV) radiation from the reducing gas species; and

(c) exposing the metal seed layer of the substrate to the remote plasma under conditions that reduce the oxide of the metal and reflows the metal in the metal seed layer.

2. The apparatus of claim 1, wherein the wavelength of the UV radiation from the reducing gas species is between about 100 nm and about 700 nm.

3. The apparatus of claim 1, wherein the remote plasma comprises radicals, ions, and UV radiation from the reducing gas species.

4. The apparatus of claim 3, wherein the remote plasma further comprises neutral molecules of the reducing gas species, and wherein exposing the metal seed layer to the remote plasma further comprises exposing the metal seed layer to neutral molecules of the reducing gas species.

5. The apparatus of claim 1, wherein the showerhead comprises a plurality of holes, the number of holes in the showerhead being between about 100 and about 900 holes.

6. The apparatus of claim 1, wherein the showerhead comprises a plurality of holes, the average diameter of the holes being between about 0.05 and about 0.5 inches.

7. The apparatus of claim 1, wherein the showerhead has a thickness between about 0.25 and about 3.0 inches.

8. The apparatus of claim 1, wherein exposing the metal seed layer to the remote plasma reduces a surface roughness of the metal seed layer.

9. The apparatus of claim 1, wherein the remote plasma apparatus is part of an electroplating or electroless plating system.

10. The apparatus of claim 9, wherein the controller further comprises instructions for transferring the substrate to a plating bath containing a plating solution in the electroplating or electroless plating system from the remote plasma apparatus.

11. The apparatus of claim 1, wherein the controller further comprises instructions for exposing the substrate to a cooling gas after exposing the metal seed layer to a remote plasma.

12. The apparatus of claim 11, wherein the controller further comprises instructions for moving the substrate towards the substrate support via one or more movable members before exposing the substrate to the cooling gas, wherein the one or more movable members are in the processing chamber configured to move the substrate to positions between the showerhead and the substrate support.

13. The apparatus of claim 1, wherein the controller further comprises instructions for heating the substrate support to a processing temperature during operations (b) and (c), wherein the processing temperature is between about 0°

C. and about 400°

C.

14. The apparatus of claim 1, wherein the metal seed layer includes at least one of copper, cobalt, ruthenium, palladium, rhodium, iridium, osmium, nickel, gold, silver, aluminum, and tungsten.

15. The apparatus of claim 1, further comprising:

a UV source, wherein the controller further comprises instructions for exposing reducing gas species to UV radiation from the UV source to form radicals of the reducing gas species.

16. The apparatus of claim 1, wherein the controller further comprises instructions for applying a charged bias on the substrate support.

17. A method of treating a substrate with a metal seed layer, the method comprising:

providing the substrate with the metal seed layer in a processing chamber, wherein a portion of the metal seed layer of the substrate has been converted to oxide of the metal;

forming a remote plasma of a reducing gas species in a remote plasma source, wherein the remote plasma comprises one or more of;

radicals, ions, and ultraviolet (UV) radiation from the reducing gas species; and

exposing the metal seed layer of the substrate to the remote plasma, wherein exposure reduces the oxide of the metal and reflows the metal in the metal seed layer.

18. The method of claim 17, further comprising exposing the reducing gas species to UV radiation from a UV source to form radicals of the reducing gas species.

19. The method of claim 17, wherein the remote plasma comprises at least two of the following:

radicals, ions, and UV radiation from the reducing gas species.

20. The method of claim 19, wherein exposing the metal seed layer to the remote plasma comprises introducing the radicals, the ions, and the UV radiation from the reducing gas species through a showerhead between the remote plasma source and the processing chamber, wherein the showerhead comprises a plurality of holes.

21. The method of claim 20, wherein a number of holes in the showerhead is between about 100 and about 900 holes.

22. The method of claim 20, wherein an average diameter of the holes is between about 0.05 and about 0.5 inches.

23. The method of claim 17, wherein the metal seed layer includes at least one of copper, cobalt, ruthenium, palladium, rhodium, iridium, osmium, nickel, gold, silver, aluminum, and tungsten.