Apparatus and techniques to treat substrates using directional plasma and point of use chemistry

• US 10,600,616 B2
• Filed: 09/06/2018
• Issued: 03/24/2020
• Est. Priority Date: 07/24/2015
• Status: Active Grant

• Current Assignee: Varian Semiconductor Equipment Associates Incorporated (Applied Materials Incorporated)
• Original Assignee: Varian Semiconductor Equipment Associates Incorporated (Applied Materials Incorporated)
• Inventors: Liang, Shurong, Biloiu, Costel, Gilchrist, Glen, Singh, Vikram, Campbell, Christopher, Hertel, Richard John, Kontos, Alex
• Primary Examiner(s): Johnston, Phillip A
• Application Number:
  US16/123,621
• Publication Number:
  US 20190006149A1
• Time in Patent Office: 565 Days
• Field of Search: 250396 R
• 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 37/08 Ion sources; Ion guns
• CPC Class Codes: H01J 37/1471 for centering, aligning or positioning of ray or beam
• CPC Class Codes: H01J 37/3053 for evaporating or etching
• CPC Class Codes: H01J 37/32357 Generation remote from the workpiece, e.g. down-stream
• CPC Class Codes: H01J 37/3244 Gas supply means

Abstract

In one embodiment, an apparatus to treat a substrate may include an extraction plate to extract a plasma beam from a plasma chamber and direct the plasma beam to the substrate. The plasma beam may comprise ions forming a non-zero angle of incidence with respect to a perpendicular to a plane of the substrate; and a gas outlet system disposed outside the plasma chamber, the gas outlet system coupled to a gas source and arranged to deliver to the substrate a reactive gas received from the gas source, wherein the reactive gas does not pass through the plasma chamber.

Claims

1. A method of treating a substrate, comprising:

extracting a plasma beam from a plasma in a plasma chamber, wherein the plasma beam is extracted through an extraction aperture of an extraction plate and comprises ions forming a non-zero angle of incidence with respect to a perpendicular to a plane of the substrate; and

directing a reactive gas from a gas source to the substrate through a plurality of gas orifices extending along top and bottom sides of the extraction aperture, wherein the reactive gas does not pass through the plasma.

2. The method of claim 1, wherein the directing the reactive gas comprises providing a gas comprising a polar molecule to the substrate, wherein the ions are inert gas ions that sputter etch a metal species from a metal layer disposed on the substrate, and wherein the polar molecule forms a volatile etch product with the metal species.

3. The method of claim 2, wherein the directing the reactive gas comprises forming a conformal coating derived from the reactive gas on the metal layer.

4. The method of claim 2, wherein the substrate comprises at least one surface feature having a sidewall, wherein the reactive gas and plasma beam etch the metal layer without redeposition of material from the metal layer on the sidewall.

5. The method of claim 2, wherein the reactive gas comprises a polar molecule, wherein the metal comprises at least one of Ta, Pt, Ru, Ti, Cu, Fe, and Co.

6. The method of claim 1, wherein the extraction aperture has an aperture width along a first direction and an aperture length along a second direction perpendicular to the first direction, wherein the aperture width is greater than the aperture length, wherein the plasma beam is a ribbon beam.

7. The method of claim 6, wherein the extraction plate comprises a plurality of gas orifices, coupled to the channel, wherein the plurality of gas orifices are arranged along at least one side of the extraction aperture along the first direction.

8. A method of etching a substrate, comprising;

providing a device structure, the device structure, comprising a metal layer, and a stack, disposed on the metal layer; and

directing a plasma beam in conjunction with a reactive gas to the substrate, wherein the plasma beam is extracted from a plasma in a plasma chamber through an extraction aperture of an extraction plate, and the reactive gas is directed from a gas source to the substrate without passing through the plasma and is further directed through a plurality of gas orifices extending along top and bottom sides of the extraction aperture.

9. The method of claim 8, wherein the plasma beam comprises ions forming a non-zero angle of incidence with respect to a perpendicular to a plane of the substrate.

10. The method of claim 8, wherein the directing the reactive gas comprises providing a gas comprising a polar molecule to the substrate, wherein the ions are inert gas ions that sputter etch a metal species from the metal layer, and wherein the polar molecule forms a volatile etch product with the metal species.

11. The method of claim 8, wherein the directing the reactive gas comprises forming a conformal coating derived from the reactive gas, on the metal layer.

12. The method of claim 8, wherein the stack comprises a sidewall, wherein the reactive gas and plasma beam etch the metal layer without redeposition of material from the metal layer on the sidewall.

13. The method of claim 8, wherein the reactive gas comprises a polar molecule, wherein the metal comprises at least one of Ta, Pt, Ru, Ti, Cu, Fe, and Co.

14. The method of claim 8, wherein the reactive gas and the metal form a volatile etch product, including the reactive gas and the metal.

15. The method of claim 8, wherein the stack comprises a plurality of layers of a magnetic random-access memory device.