Topography reduction and control by selective accelerator removal

• US 20090280649A1
• Filed: 08/06/2007
• Published: 11/12/2009
• Est. Priority Date: 10/20/2003
• Status: Active Grant

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Rea, Mark L., Webb, Eric G., Mayer, Steven T., Hill, Richard S., Stowell, R. Marshall, Kepten, Avishai
• Granted Patent: US 8,470,191 B2
• Time in Patent Office: Days
• US Class Current: 438/676
• CPC Class Codes: B23H 5/08 Electrolytic grinding
• CPC Class Codes: C25D 17/001 Apparatus specially adapted for electrolytic coating of wafers, e.g. semiconductors or solar cells
• CPC Class Codes: C25D 17/06 Suspending or supporting devices for articles to be coated
• CPC Class Codes: C25D 17/14 for pad-plating
• CPC Class Codes: C25D 5/02 Electroplating of selected surface areas
• CPC Class Codes: C25D 5/06 Brush or pad plating
• CPC Class Codes: C25D 5/08 Electroplating with moving electrolyte e.g. jet electroplating using locally applied jets of electrolyte C25D5/026
• CPC Class Codes: C25D 5/34 Pretreatment of metallic surfaces to be electroplated
• CPC Class Codes: C25D 7/123 Semiconductors first coated with a seed layer or a conductive layer
• CPC Class Codes: C25F 3/16 Polishing
• CPC Class Codes: C25F 3/30 of semiconducting materials
• 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 21/2885 using an external electrical current, i.e. electro-deposition
• CPC Class Codes: H01L 21/32115 Planarisation
• CPC Class Codes: H01L 21/3212 by chemical mechanical polishing [CMP]
• CPC Class Codes: H01L 21/32134 by liquid etching only
• CPC Class Codes: H01L 21/7684 Smoothing; Planarisation
• CPC Class Codes: H01L 21/76849 the layer being positioned on top of the main fill metal
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material

Abstract

Plating accelerator is applied selectively to a substantially-unfilled wide (e.g., low-aspect-ratio feature cavity. Then, plating of metal is conducted to fill the wide feature cavity and to form an embossed structure in which the height of a wide-feature metal protrusion over the metal-filled wide-feature cavity is higher than the height of metal over field regions. Most of the overburden metal is removed using non-contact techniques, such as chemical wet etching. Metal above the wide feature cavity protects the metal-filled wide-feature interconnect against dishing, and improved planarization techniques avoid erosion of the metal interconnect and dielectric insulating layer. In some embodiments, plating of metal onto a substrate is conducted to fill narrow (e.g., high-aspect-ratio feature cavities) in the dielectric layer before selective application of plating accelerator and filling of the wide feature cavity.

Claims

1. A method of conducting localized liquid treating of an integrated circuit substrate having an exposed substrate surface, comprising processes of:

contacting a treating area of said substrate surface with a treating liquid, said treating area being substantially less than said exposed substrate surface;

2. A method as in claim 1, further comprising:

not contacting a non-treatment portion of said substrate surface with treating liquid during said contacting said treating area.

3. A method as in claim 1 wherein said contacting a treating area of said substrate surface with a treating liquid comprises:

applying said treating liquid to a treating-liquid-impact area of said substrate surface.

4. A method as in claim 1 wherein said applying said treating liquid to a treating-liquid-impact area of said substrate surface comprises:

discharging a treating liquid from an applicator at an applicator location in a treating cell;

locating said substrate surface proximate to said applicator location so that said treating liquid impacts said treating-liquid-impact area of said substrate surface.

5. An apparatus for conducting localized liquid treating of an integrated circuit substrate having a substrate surface, comprising:

a wafer chuck for holding a substrate wafer in a treating cell;

an applicator in said etching cell to discharge a treating liquid at an applicator location onto a treating-liquid-impact area of a substrate surface, said treating-liquid-impact area being a portion less than one of said substrate surface.

6. An apparatus as in claim 5 characterized by:

said wafer chuck being operable to move said substrate relative to said applicator location so that said treating liquid wets a treating area greater than said treating-liquid-impact area, said treating area having an area substantially less than said substrate surface.

7. An apparatus as in claim 6 characterized by:

said wafer chuck being operable to rotate said substrate to generate a circular treating area.

8. An apparatus as in claim 6 characterized by:

said applicator being operable to move said applicator location of said applicator relative to said substrate surface, thereby moving a treating area.

8-1. A system for forming metal structures in an electronic device, comprising:

a first electroplating module to conduct a first metal deposition with the first metal plating solution to deposit metal in at least a first feature cavity of a substrate;

a surface-and-edge-treatment (SET) module, said SET module being operable to treat a substrate surface of said substrate after a first metal deposition in said first electroplating module, said SET module being operable to cause an accelerator to become attached selectively to a substrate at least in a second feature cavity, said second feature cavity having an aspect ratio smaller than a first feature cavity, thereby forming an acceleration region at least in said second feature cavity, with relatively little or no accelerator attached to a non-acceleration region of said substrate, said non-acceleration region comprising at least a field region of said substrate surface;

a second electroplating module, located operationally after said SET module, to conduct a second metal deposition with a second metal plating solution to deposit metal on said substrate surface at least in said second feature cavity; and

an isotropic metal removal module, said metal removal module being operable isotropically to remove deposited metal from said substrate after said second metal deposition.

9. An apparatus for selectively plating metal on a substrate comprising:

a plating chamber;

a bath vessel located in said plating chamber, said bath vessel operable for containing a plating bath containing plating liquid;

a plating zone, said plating zone located in said plating chamber and being operable to plate metal on at least a plating portion of a substrate in said plating bath;

a pad zone located in said plating chamber, said pad zone being substantially adjacent to said plating zone;

a pad assembly comprising a buffing pad, said pad assembly located at least partially in said pad zone, said pad assembly being operable to buff at least a buffing portion of a substrate located in said pad zone, said buffing portion being separate from a plating portion;

a substrate holder, said substrate holder being operable in said plating chamber, said substrate holder being operable to hold a substrate wafer, said substrate holder being operable to move at least a portion of a substrate alternately between said plating zone and said pad zone.

10. An apparatus for selectively treating a substrate comprising:

a treating chamber;

a bath vessel located in said treating chamber, said bath vessel operable for containing a treating bath containing treating liquid;

a treating zone, said treating zone located in said treating chamber and being operable to treat at least a treating portion of a substrate in said treating bath;

a substrate adjustment zone located in said treating chamber, said substrate adjustment zone being substantially adjacent to said treating zone;

a substrate adjustment assembly, said substrate adjustment assembly located at least partially in said substrate adjustment zone, said substrate adjustment assembly being operable to adjust at least an adjustment portion of a substrate located in said substrate adjustment zone, said adjustment portion being separate from a treating portion;

a substrate holder, said substrate holder being operable in said treating chamber, said substrate holder being operable to hold a substrate wafer, said substrate holder being operable to move at least a portion of a substrate alternately between said treating zone and said substrate adjustment zone.

11. A method of selectively plating metal on a substrate comprising:

providing a plating bath containing plating liquid, said plating bath comprising a plating zone;

providing a substrate having an acceleration region and a non-acceleration region, said acceleration region comprising attached accelerator and said non-acceleration region comprising relatively little or no accelerator;

moving at least a portion of said substrate into said plating zone, wherein said attached accelerator in said acceleration region increases a rate of metal deposition in said acceleration region relative to a rate of metal deposition in said non-acceleration region.

12. A method of selectively plating metal as in claim 11, further comprising:

not contacting said portion in said plating zone with a rubbing pad.