US-20260128253-A1 - SYSTEM AND METHOD FOR HIGH ANGLE ION BEAM

Abstract

A processing system may include a plasma chamber operable to generate a plasma, and an extraction assembly, arranged along a side of the plasma chamber. The extraction assembly may include a screen plate, disposed immediately adjacent to the side of the plasma chamber, the screen plate having an angled portion that comprises a screen aperture, to extract an angled ion beam towards a first end of the extraction assembly. The extraction assembly may also include an acceleration plate, disposed outside of the screen plate, the acceleration plate having a middle portion that is shaped according to an outer surface of the screen plate. As such, the acceleration plate may include an acceleration aperture, aligned with the screen aperture, and the acceleration plate may include a distal portion adjacent to the middle portion, the distal portion having a distal end that extends beyond an end of the screen plate.

Inventors

• Costel Biloiu
• Alexander S. Perel
• Alexandre Likhanskii
• Kevin T. Ryan
• Daniel Distaso
• Kevin M. Daniels
• Christopher Campbell

Assignees

• APPLIED MATERIALS, INC.

Dates

Publication Date

20260507

Application Date

20241105

Claims (19)

1. 1 . A processing system, comprising: a plasma chamber operable to generate a plasma; and an extraction assembly, arranged along a side of the plasma chamber, the extraction assembly comprising: a screen plate, disposed immediately adjacent to the side of the plasma chamber, the screen plate having an angled portion that comprises a screen aperture, to extract an angled ion beam towards a first end of the extraction assembly; and an acceleration plate, disposed outside of the screen plate, the acceleration plate having a middle portion that is shaped according to an outer surface of the screen plate, wherein the acceleration plate comprises an acceleration aperture, aligned with the screen aperture, and wherein the acceleration plate comprises a distal portion adjacent to the middle portion, the distal portion having a distal end that extends beyond an end of the screen plate.
2. 2 . The processing system of claim 1 , wherein the outer surface of the screen plate has a staggered structure, the staggered structure comprising: a first portion, disposed away from the plasma chamber, and disposed along a first edge of the angled portion; and a second portion, disposed along a second edge of the angled portion, and immediately adjacent to the plasma chamber.
3. 3 . The processing system of claim 2 , wherein the acceleration plate comprises: has a first section, aligned over the first portion of the screen plate; a first angled section, having a first edge, adjacent to the first section, and containing the acceleration aperture; and a second section, having an inner edge adjacent to a second edge of the angled section, and extending over the second portion of the screen plate and beyond an end of the second portion.
4. 4 . The processing system of claim 3 , wherein the acceleration plate further comprises a second angled section, disposed adjacent to an outer edge of the second section, and angled toward the plasma chamber.
5. 5 . The processing system of claim 4 , wherein the plasma chamber comprises an enclosure having an angled side region, and wherein the second angled section is angled to match the angled side region of the plasma chamber.
6. 6 . The processing system of claim 1 , further comprising a process chamber, disposed along the side of the plasma chamber, wherein the acceleration plate is disposed within the process chamber.
7. 7 . The processing system of claim 6 , further comprising a substrate stage, disposed within the process chamber, the substrate stage comprising a drive, arranged to move the substrate stage along at least a first scan direction with respect to the extraction assembly.
8. 8 . The processing system of claim 7 , wherein the screen aperture and the acceleration aperture are elongated along a aperture axis that extends perpendicularly to the first scan direction.
9. 9 . The processing system of claim 7 , wherein the substrate stage defines a substrate plane that lies parallel to the first scan direction, and wherein the extraction assembly is arranged to extract an ion beam from the plasma chamber and direct the ion beam to the substrate plane along a beam trajectory that forms an angle of 40 degrees or more with respect to a perpendicular to the substrate plane.
10. 10 . The processing system of claim 9 , wherein the extraction assembly is arranged to generate an ion angular distribution of less than 10 degrees.
11. 11 . The processing system of claim 9 , wherein the extraction assembly is arranged to generate a set of electric field lines when the ion beam is extracted from the plasma chamber, and wherein the electric field lines do not overlap with the ion beam.
12. 12 . The processing system of claim 1 , further comprising a bias voltage supply, arranged to bias the acceleration plate at an acceleration potential with respect to the plasma chamber.
13. 13 . The processing system of claim 12 , wherein the bias voltage supply is further coupled to bias the substrate holder at the acceleration potential.
14. 14 . The processing system of claim 12 , wherein wherein the distal portion is arranged as a separate part from the middle portion, and wherein the middle portion and the distal portion are biased at the acceleration potential.
15. 15 . The processing system of claim 1 , wherein the acceleration plate is perforated, comprising a plurality of holes.
16. 16 . The processing system of claim 14 , wherein the acceleration plate comprises a thickness t and the plurality of holes comprise a hole diameter Φ wherein a ( t/Φ)≥1.
17. 17 . The processing system of claim 14 , wherein the plurality of holes have a chamfered shape.
18. 18 . A method of processing a substrate, comprising: generating a plasma in a plasma chamber; and extracting an angled ion beam from the plasma chamber through an extraction assembly, comprising: a screen plate, having an angled portion that comprises a screen aperture, to extract the angled ion beam towards a first end of the extraction assembly; and an acceleration plate, having a middle portion that is shaped according to an outer surface of the screen plate, and having an acceleration aperture, aligned with the screen aperture, and directing the angled ion beam to the substrate, wherein the angled ion beam does not overlap a set of electric filed lines that are generated by the extraction assembly.
19. 19 . The method of claim 18 , wherein the acceleration plate comprises: a first section, aligned over a first portion of the screen plate; a first angled section, having a first edge, adjacent to the first section, and containing the angled aperture; and a second section, having an inner edge adjacent to a second edge of the angled section, and extending over a second portion of the screen plate and beyond an end of the second portion.

Description

FIELD OF THE DISCLOSURE The present embodiments relate to a processing apparatus, and more particularly, to an apparatus enabling ion extraction from a plasma at high on-substrate incidence angle. BACKGROUND OF THE DISCLOSURE Known apparatus used to treat substrates with ions include beamline ion implanters and plasma immersion ion implantation tools. These approaches are useful for treating substrates with ions over a range of energies. In beamline ion implanters, ions are extracted from a source, mass analyzed and then transported to the substrate surface. In plasma immersion ion implantation apparatus, a substrate is located in the same chamber while the plasma is generated adjacent to the plasma. The substrate is set at negative potential with respect to the plasma, and positive ions crossing the plasma sheath in front of the substrate may impinge on the substrate perpendicularly (at a zero incidence angle). Many of such approaches employ perpendicular incidence on a substrate or wafer, while other applications employ angled etching such as controlled etching of trench sidewalls, hole elongation, photoresist shrinking, line edge roughness (LER)/line width roughness (LWR) improvement, and magnetic random memory structures etching, where ion beams are defined by a non-zero mean angle of incidence with respect to the perpendicular to the substrate. Control of such processes may be more difficult than control of ion beam processing at normal incidence. Some high angle of incidence approaches suffer from a limited incidence angle, and high glitching rates, for instance. It is with respect to these and other considerations, the present disclosure is provided. SUMMARY In one embodiment, a processing system is provided. The processing system may include a plasma chamber operable to generate a plasma, and an extraction assembly, arranged along a side of the plasma chamber. The extraction assembly may include a screen plate, disposed immediately adjacent to the side of the plasma chamber, the screen plate having an angled portion that comprises a screen aperture, to extract an angled ion beam towards a first end of the extraction assembly. The extraction assembly may also include an acceleration plate, disposed outside of the screen plate, the acceleration plate having a middle portion that is shaped according to an outer surface of the screen plate. As such, the acceleration plate may include an acceleration aperture, aligned with the screen aperture, and the acceleration plate may include a distal portion adjacent to the middle portion, the distal portion having a distal end that extends beyond an end of the screen plate. In another embodiment, a method of processing a substrate is provided. The method may include generating a plasma in a plasma chamber, and extracting an angled ion beam from the plasma chamber through an extraction assembly. The extraction assembly may include a screen plate, having an angled portion that has a screen aperture, to extract the angled ion beam towards a first end of the extraction assembly. The extraction assembly may also include an acceleration plate, having a middle portion that is shaped according to an outer surface of the screen plate, and having an acceleration aperture, aligned with the screen aperture. The method may further include directing the angled ion beam to the substrate, wherein the angled ion beam does not overlap a set of electric filed lines that are generated by the extraction assembly. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings illustrate exemplary approaches of the disclosed embodiments so far devised for the practical application of the principles thereof. FIG. 1 shows a block diagram of a processing apparatus including a high angle extraction assembly in accordance with various embodiments of the disclosure; FIG. 2A shows a computer simulation in side cross-sectional view of a variant of an extraction assembly of the processing apparatus of FIG. 1, during ion beam extraction, in accordance with various embodiments of the disclosure; FIG. 2B shows a computer simulation in side cross-sectional view of another variant of an extraction assembly of the processing apparatus of FIG. 1, during ion beam extraction, in accordance with various embodiments of the disclosure; FIG. 2C shows a computer simulation in side cross-sectional view of a further variant of an extraction assembly of the processing apparatus of FIG. 1, during ion beam extraction, in accordance with various embodiments of the disclosure; FIG. 3A shows a computer simulation in side cross-sectional view of a variant of an extraction assembly of FIG. 2A, during ion beam extraction, showing ion trajectories and electric field lines, in accordance with various embodiments of the disclosure; FIG. 3B shows a computer simulation of the scenario of FIG. 3A, showing secondary electrons trajectories; FIG. 3C shows a computer simulation in side cross-sectional view of a variant of an extrac