METHODS AND APPARATUS FOR MAKING INTEGRATED-CIRCUIT WIRING FROM COPPER, SILVER, GOLD, AND OTHER METALS

• US 20080067064A1
• Filed: 09/26/2007
• Published: 03/20/2008
• Est. Priority Date: 01/18/2000
• Status: Active Grant

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Forbes, Leonard, Ahn, Kie
• Granted Patent: US 7,670,469 B2
• Time in Patent Office: Days
• US Class Current: 204/298.13
• CPC Class Codes: C23C 14/3471 Introduction of auxiliary energy into the plasma
• CPC Class Codes: C23C 16/517 using a combination of discharges covered by two or more of groups C23C16/503 - C23C16/515
• CPC Class Codes: G02F 1/13454 Drivers integrated on the active matrix substrate G02F1/136277 takes precedence
• CPC Class Codes: H01J 37/3408 Planar magnetron sputtering
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76846 Layer combinations
• CPC Class Codes: H01L 21/76856 by treatment in plasmas or gaseous environments, e.g. nitriding a refractory metal liner
• CPC Class Codes: H01L 21/76873 for electroplating
• CPC Class Codes: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621

Abstract

In recent years, copper wiring has emerged as a promising substitute for the aluminum wiring in integrated circuits, because copper offers lower electrical resistance and better reliability at smaller dimensions than aluminum. However, use of copper typically requires forming a diffusion barrier to prevent contamination of other parts of an integrated circuit and forming a seed layer to facilitate copper plating steps. Unfortunately, conventional methods of forming the diffusion barriers and seed layers require use of separate wafer-processing chambers, giving rise to transport delays and the introduction of defect-causing particles. Accordingly, the inventors devised unique wafer-processing chambers and methods of forming barrier and seed layers. One embodiment of the wafer-processing chamber includes equipment for physical vapor deposition and equipment for chemical vapor deposition to facilitate formation of diffusion barriers and seed layers within one chamber, thereby promoting fabrication efficiency and reducing defects.

Claims

1. A processing chamber for one or more integrated-circuit assemblies, comprising:

a vacuum chamber including a substrate holder, at least one sputtering target, a plasma power source;

a gas emission device selectively connected to a plurality of gaseous material sources, a heater; and

a gas emission device disposed adjacent the sputtering target.

2. The processing chamber of claim 1, wherein the at least one sputtering target includes at least one material from the list comprising copper, silver, gold, tungsten;

and

at least one of the gaseous material sources includes at least one material from the list comprising oxygen, nitrogen, aluminum, silicon, germanium, copper, silver, gold.

3. The processing chamber of claim 1, wherein the gas emission device selectively connect to the plurality of gaseous material sources is enabled to chemical vapor deposit at least one of a graded composition of WSi_x, where x varies from 2.0 to 2.5, and nitrided graded WSi_xN_y.

4. The processing chamber of claim 1, wherein the gas emission device selectively connected to the plurality of gaseous material sources includes an ECR device to excite a plasma including argon gas.

5. The processing chamber of claim 1, further comprising at least one of a movable shutter disposed adjacent the at least one sputtering target, an isolation valve positioned in an inlet into the chamber, the sputtering target is below the substrate holder, and the gas emission device disposed adjacent the sputtering target further comprises a non-reactive gas source disposed to sweep across the sputtering target for preventing contamination during operation of the gas emission device selectively connected to a plurality of gaseous material sources.

6. The processing chamber of claim 3, wherein the gas emission device selectively connected to the plurality of gaseous material sources is adapted to deposit tungsten by introducing tungsten hexafluoride and hydrogen gases, introducing silane gas, and terminating introduction of silane gas before terminating introduction of tungsten hexafluoride and hydrogen gases.

7. The processing chamber of claim 1, wherein the gas emission device selectively connected to the plurality of gaseous material sources includes a plurality of mass flow-controllers, and include a WF₆ source, a SiH₄ source, and an N₂ source.

8. A processing chamber for one or more integrated-circuit assemblies, comprising:

a sputter target within the chamber;

a plasma generator within the chamber;

a chemical vapor deposition system within the chamber;

a movable shutter disposed to isolate the plasma generator during operation of the chemical vapor deposition system; and

a gas source adapted to sweep the sputter target for preventing contamination of the sputter target during operation of the chemical vapor deposition system.

9. The processing chamber of claim 8, wherein the gas source includes at least one of one or more turns of electrically conductive tubing and an RF emission coil.

10. A processing chamber for one or more integrated-circuit assemblies, comprising:

a wafer holder for holding a wafer or substrate;

means for sputtering a material onto a surface of a wafer held by the wafer holder, including;

one or more sputter-target holders within the chamber for holding a sputter target;

a plasma source coupled to the chamber; and

means for vapor-depositing a material, including;

one or more mass-flow controllers coupled to the chamber; and

a gas-emission tube coupled to at least one of the mass-flow controllers and having one or more orifices oriented for emitting gas toward a sputter target held by the one or more sputter target holders.

11. The processing chamber of claim 10, wherein the gas-emission tube comprises a coiled tube having one or more turns.

12. The processing chamber of claim 11, further comprising a single vacuum chamber, a sputtering target holder within the chamber below the wafer holder, an electron-cyclotron-resonance plasma source coupled to the chamber, and at least one mass-flow controller coupled to the chamber.

13. The processing chamber of claim 12, wherein the vacuum chamber includes walls of at least one of stainless steel and glass.

14. The processing chamber of claim 12, wherein the chamber includes an RF-gas emission coil below the sputtering target holder.

15. The processing chamber of claim 14, wherein the coil includes a horizontal spiral.

16. The processing chamber of claim 14, wherein the coil includes two turns of 6.5 millimeter tubing.

17. The processing chamber of claim 12, wherein the sputtering target holder is adapted to provide a bias voltage to a target.

18. The processing chamber of claim 12, wherein the plasma source includes an isolation valve adapted to selectively isolate the plasma source from the chamber.

19. A processing chamber for one or more integrated-circuit assemblies, comprising:

a vacuum chamber including a substrate holder, at least one sputtering target including at least one material from the list comprising copper, silver, gold, tungsten;

a plasma power source selected from a capacitive radio frequency generator, an inductive radio frequency generator, and an ECR device, to excite a plasma;

a gas emission device selectively connected to a plurality of gaseous material sources including at least one material from the list comprising oxygen, nitrogen, hydrogen, argon, aluminum, silicon, germanium, copper, silver, gold, tungsten, and enabled to mix gaseous material sources to chemical vapor deposit at least one of a graded composition of WSi_x, where x varies from 2.0 to 2.5, and nitrided graded WSi_x; and

a gas emission device disposed adjacent the sputtering target.

20. The processing chamber of claim 19, further comprising at least one of a movable shutter disposed adjacent the at least one sputtering target, an isolation valve positioned in an inlet into the chamber, the sputtering target disposed below the integrated circuit assemblies, and the gas emission device disposed adjacent the sputtering target disposed to sweep a non-reactive gas source across the sputtering target during operation of the gas emission device selectively connected to a plurality of gaseous material sources.

21. The processing chamber of claim 20, wherein the gas emission device selectively connect to the plurality of gaseous material sources includes a heater, mass flow gas controllers, and a timer to deposit tungsten by introducing a selected flow of tungsten hexafluoride (WF₆) and hydrogen gases (H₂), introducing a selected flow of silane gas (SiH₄), and terminating introduction of silane gas before terminating introduction of tungsten hexafluoride and hydrogen gases.