Electromagnet array in a sputter reactor

• US 20100155223A1
• Filed: 01/28/2010
• Published: 06/24/2010
• Est. Priority Date: 05/26/2004
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: SUNDARRAJAN, Arvind, GUNG, Tza-Jing, GOPALRAJA, Praburam, FU, Xinyu, GILLARD, Andrew S., PERRIN, Mark A., HAMMOND, Edward P. IV, FORSTER, John C.
• Granted Patent: US 8,871,064 B2
• Time in Patent Office: Days
• US Class Current: 204/192.300
• CPC Class Codes: C23C 14/046 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 14/0641 Nitrides C23C14/0617 takes precedence
• CPC Class Codes: C23C 14/165 by cathodic sputtering
• CPC Class Codes: C23C 14/358 Inductive energy
• CPC Class Codes: C23F 4/00 Processes for removing metallic material from surfaces, not provided for in group C23F1/00 or C23F3/00
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/32623 Mechanical discharge control means
• CPC Class Codes: H01J 37/3266 Magnetic control means
• CPC Class Codes: H01J 37/32688 Multi-cusp fields
• CPC Class Codes: H01J 37/3408 Planar magnetron sputtering
• CPC Class Codes: H01L 21/2855 by physical means, e.g. sputtering, evaporation H01L21/28518 - H01L21/28537 and H01L21/28568 take precedence
• CPC Class Codes: H01L 21/76844 Bottomless liners
• CPC Class Codes: H01L 21/76846 Layer combinations
• CPC Class Codes: H01L 21/76865 Selective removal of parts of the layer H01L21/76844 takes precedence

Abstract

A multi-step process performed in a plasma sputter chamber including sputter deposition from the target and argon sputter etching of the substrate. The chamber includes a quadruple electromagnetic coil array coaxially arranged in a rectangular array about a chamber axis outside the sidewalls of a plasma sputter reactor in back of an RF coil within the chamber. The coil currents can be separately controlled to produce different magnetic field distributions, for example, between a sputter deposition mode in which the sputter target is powered to sputter target material onto a wafer and a sputter etch mode in which the RF coil supports the argon sputtering plasma. A TaN/Ta barrier is first sputter deposited with high target power and wafer bias. Argon etching is performed with even higher wafer bias. A flash step is applied with reduced target power and wafer bias.

Claims

1. In a plasma sputter reactor having a substrate support disposed in a plane perpendicular to an axis of a vacuum chamber having sidewalls formed around the axis and a sputter target arranged in opposition to the substrate support across a space along the axis, an electromagnet array of at least three separately controllable electromagnet coils arranged at axial positions relative to the axis between the sputter target and the substrate support and all being configured to be connected to at least one DC power supply,

wherein three electromagnet coils of the at least three electromagnet coil are arranged about the axis in a triangular array, and

wherein at least two of the three electromagnet coils are disposed at different radii from the axis and at least two of the three electromagnet coils are disposed at different axial positions relative to the axis.

2. The electromagnet array of claim 1, wherein the at least three electromagnet coils are separated apart from each other to allow magnetic field to form between the them.

3. The electromagnet array of claim 1, wherein the at least three electromagnet coils comprise four electromagnet coils, wherein no more than two of the four electromagnet coils are disposed at a same radius from the axis and no more than two of the four electromagnet coils are disposed at a same axial position relative to the axis.

4. The electromagnet array of claim 3, wherein the four electromagnet coils are arranged in a rectangular array about the axis.

5. The electromagnet array of claim 1, further comprising a multi-wrap cooling coil thermally contacting at least two of the electromagnet coils.

6. A method of operating the electromagnet array of claim 1, comprising the steps of:

a first process step of generating a first plasma in the vacuum chamber while a substrate disposed on the substrate support including passing co-rotating currents through two of the three electromagnet coils; and

a second process step of generating a second plasma in the vacuum chamber while the substrate is disposed on the substrate support including passing anti-rotating currents through the two electromagnet coils.

8. The reactor of claim 6, further comprising an RF coil disposed to overlap said array along said axis.

7. A plasma sputter reactor, comprising:

a chamber body arranged about an axis;

a support for supporting within said reactor a substrate to be plasma processed on a front face thereof;

a sputtering target in opposition to the support along the axis and

an array of a plurality of electromagnet coils arranged about said chamber body, wherein three of the electromagnet coils are arranged in a triangular array, at least some of the three electromagnet coils being independently powerable.

9. A method of operating a plasma sputter reactor having a substrate support disposed in a plane perpendicular to an axis of a vacuum chamber having sidewalls formed around the axis and a sputter target arranged in opposition to the substrate support across a space along the axis, an electromagnet array comprising a plurality of electromagnet coils including three separately controllable electromagnet coils arranged in a triangular array about the axis at a plurality of axial positions relative to the axis between the sputter target and three substrate support and at a plurality of axial positions relative to the axis between the sputter target and the substrate support and at a plurality of radii from the axis and all of the three electromagnet coils being configured to be connected to at least one DC power supply, comprising the steps of:

a first process step of generating a first plasma in the reactor while a substrate disposed on the substrate support including passing co-rotating currents through two of the three electromagnet coils; and

a second process step of generating a second plasma in the reactor while the substrate is disposed on the substrate support including passing anti-rotating currents through the two electromagnet coils.

10. The method of claim 9, wherein one of the first and second process steps includes sputtering material from the target onto the substrate and the other of the first and second process steps includes etching the substrate with argon ions.