KR-102961051-B1 - Mismatched optical system for angle control of extracted ion beam

Abstract

An ion source capable of extracting a ribbon ion beam having improved vertical angle uniformity is disclosed. The extraction plate and the extraction optical system are designed such that at least one non-uniform gap exists between adjacent components. The non-uniform gap may be effective in reducing the angular diffusion non-uniformity of the extracted ribbon ion beam. Specifically, for a given gap in the Z direction, ions extracted from regions having lower plasma density may have greater vertical angle diffusion. A larger gap in the Z direction between components in such regions may cause the vertical angle diffusion to be closer to the vertical angle diffusion of ions extracted from regions having higher plasma density. The non-uniform gap may be created by having a flat or curved extraction plate and flat, convex, or concave electrodes. In certain embodiments, the non-uniform gap is located between the extraction plate and the suppression electrode.

Inventors

• 리칸스키, 알렉산드레
• 슈어, 제이 티.
• 마할린감, 순다카르
• 클레이, 네빈

Assignees

• 어플라이드 머티어리얼스, 인코포레이티드

Dates

Publication Date

20260508

Application Date

20220927

Priority Date

20211026

Claims (20)

1. As an ion source, A chamber comprising a first end, a second end, and a plurality of walls connecting the first end and the second end—one of the plurality of walls being an extraction plate having an extraction aperture, and the extraction aperture having a width greater than its height—; A plasma generator for generating plasma within the above chamber - plasma is generated within the above chamber, the plasma density within the above chamber is non-uniform, and a first region of the above chamber has a plasma density greater than a second region -; and A suppression electrode disposed outside the chamber and in close proximity to the extraction aperture—the gap between the outer surface of the extraction plate and the surface of the suppression electrode facing the extraction plate is smaller in the width direction near the first region than the gap near the second region, and the difference between the gap near the first region and the gap near the second region is at least 0.3 mm. An ion source containing
2. delete
3. In paragraph 1, The above plasma density is greater at the center of the extraction aperture than at the edge of the extraction aperture, in an ion source.
4. In paragraph 3, An ion source, wherein the outer surface of the extraction plate is flat and the surface of the inhibition electrode facing the extraction plate is convex.
5. In paragraph 3, An ion source, wherein the outer surface of the extraction plate is convex and the surface of the inhibition electrode facing the extraction plate is flat.
6. In paragraph 3, An ion source in which the outer surface of the extraction plate is convex, and the surface of the inhibition electrode facing the extraction plate is convex.
7. In paragraph 1, The above plasma density is greater at the edge of the extraction aperture than at the center of the extraction aperture, in an ion source.
8. In Paragraph 7, An ion source, wherein the outer surface of the extraction plate is flat and the surface of the inhibition electrode facing the extraction plate is concave.
9. In Paragraph 7, An ion source, wherein the outer surface of the extraction plate is concave, and the surface of the inhibition electrode facing the extraction plate is flat or concave.
10. In paragraph 1, The above plasma generator is an ion source including a heat-dissipating cathode.
11. In paragraph 1, An ion source in which plasma is generated within the chamber, the plasma density within the chamber is non-uniform, and the gap between the outer surface of the extraction plate and the surface of the inhibition electrode facing the extraction plate is smallest where the plasma density is greatest.
12. In paragraph 1, An ion source comprising at least one additional electrode, wherein the at least one additional electrode is positioned such that the suppression electrode is disposed between the at least one additional electrode and the extraction plate, and a second non-uniform gap is positioned between a pair of electrodes adjacent to each other among the suppression electrode and the at least one additional electrode.
13. As an ion implantation system, The ion source of claim 1; Mass spectrometer; and Platton An ion implantation system including
14. As an ion source, A chamber comprising a first end, a second end, and a plurality of walls connecting the first end and the second end—one of the plurality of walls being an extraction plate having an extraction aperture, and the extraction aperture having a width greater than its height—; A plasma generator for generating plasma within the above chamber; A suppression electrode disposed outside the chamber and in close proximity to the extraction aperture; and At least one additional electrode positioned such that the suppression electrode is disposed between at least one additional electrode and the extraction plate. Includes, An ion source having a non-uniform gap in the width direction disposed between a pair of electrodes adjacent to each other among the suppression electrode and the at least one additional electrode.
15. In Paragraph 14, The above at least one additional electrode includes a ground electrode, and the non-uniform gap is an ion source disposed between the inhibition electrode and the ground electrode.
16. In paragraph 15, An ion source in which the surface of the inhibition electrode facing the ground electrode is convex, and the surface of the ground electrode facing the inhibition electrode is flat or convex.
17. In paragraph 15, An ion source in which the surface of the inhibition electrode facing the ground electrode is flat, and the surface of the ground electrode facing the inhibition electrode is convex.
18. In Paragraph 14, The above at least one additional electrode comprises a second electrode and a third electrode, and the non-uniform gap is disposed between the inhibition electrode and the second electrode or between the second electrode and the third electrode, an ion source.
19. In Paragraph 14, The at least one additional electrode comprises a second electrode, a third electrode and a fourth electrode, and the non-uniform gap is an ion source disposed between the inhibition electrode and the second electrode, between the second electrode and the third electrode, or between the third electrode and the fourth electrode.
20. As an ion source, A chamber comprising a first end, a second end, and a plurality of walls connecting the first end and the second end—one of the plurality of walls is an extraction plate having an extraction aperture, the direction between the first end and the second end is the X direction, the direction perpendicular to the X direction is the Y direction, and the extraction aperture has a dimension in the X direction greater than a dimension in the Y direction—; A plasma generator for generating plasma within the above chamber - plasma is generated within the above chamber, the plasma density within the above chamber is non-uniform, and a first region of the above chamber has a plasma density greater than a second region -; and A suppression electrode disposed outside the chamber and in close proximity to the extraction aperture—the gap between the outer surface of the extraction plate and the surface of the suppression electrode facing the extraction plate is smaller near the first region in the X direction than the gap near the second region, and the difference between the gap near the first region and the gap near the second region is at least 0.3 mm. An ion source containing

Description

Mismatched optical system for angle control of extracted ion beam This application claims priority to U.S. patent application serial number 17/510,996 filed on October 26, 2021, the entire contents of said U.S. patent application are incorporated herein by reference. The present disclosure describes systems for controlling the angular diffusion of a ribbon ion beam extracted from an ion source, such as an indirectly heated cathode (IHC) ion source. Semiconductor devices are manufactured using multiple processes, some of which implant ions into the workpiece. Various ion sources can be used to generate ions. One such mechanism is the inductive cathode (IHC) ion source. An IHC ion source includes a filament positioned behind a cathode. The cathode can be maintained at a higher voltage than the filament. As current passes through the filament, the filament emits thermionic electrons that are accelerated toward the more positively charged cathode. These thermionic electrons serve to heat the cathode, which in turn causes the cathode to emit electrons into the chamber of the ion source. The cathode is positioned at one end of the chamber. A repeller is typically positioned at the end of the chamber facing the cathode. In certain embodiments, the IHC ion source is configured to extract a ribbon ion beam, and the width of the ribbon ion beam is much greater than the height of the ribbon ion beam. Unfortunately, in many systems, the angular spread of the extracted ribbon ion beam is not uniform along the beam width. For example, the range of beam angles near the center of the ribbon ion beam may be smaller than the range of beam angles near the edges of the ribbon ion beam. In some embodiments, additional components in the beamline, such as quadrupole lenses, may be utilized to attempt to compensate for this non-uniformity. These reliefs may add additional complexity and cost to the beamline system. Therefore, it would be beneficial to have a system capable of controlling the uniformity of the vertical angle diffusion of the ribbon ion beam extracted from the ion source. An ion source capable of extracting a ribbon ion beam having improved vertical angle uniformity is disclosed. The extraction plate and the extraction optical system are designed such that at least one non-uniform gap exists between adjacent components. The non-uniform gap may be effective in reducing the angular diffusion non-uniformity of the extracted ribbon ion beam. Specifically, for a given gap in the Z direction, ions extracted from regions having lower plasma density may have greater vertical angle diffusion. A larger gap in the Z direction between components in such regions may cause the vertical angle diffusion to be closer to the vertical angle diffusion of ions extracted from regions having higher plasma density. The non-uniform gap may be created by having a flat or curved extraction plate and flat, convex, or concave electrodes. In certain embodiments, the non-uniform gap is located between the extraction plate and the suppression electrode. According to one embodiment, an ion source is disclosed. The ion source comprises: a chamber comprising a first end, a second end, and a plurality of walls connecting the first end and the second end—one of the plurality of walls is an extraction plate having an extraction aperture, and the extraction aperture has a width greater than its height—; a plasma generator for generating plasma within the chamber; and a suppression electrode disposed outside the chamber and in proximity to the extraction aperture—the gap between the outer surface of the extraction plate and the surface of the suppression electrode facing the extraction plate is non-uniform in the width direction, and the difference in the gap is at least 0.3 mm. In some embodiments, the plasma is generated within the chamber, the plasma density within the chamber is non-uniform, the first region of the chamber has a plasma density greater than the second region, and the gap between the outer surface of the extraction plate and the surface of the suppression electrode facing the extraction plate is smaller near the first region than the gap near the second region. In some embodiments, the plasma density is greater at the center of the extraction aperture than at the edge of the extraction aperture. In certain embodiments, the outer surface of the extraction plate is flat, and the surface of the suppression electrode facing the extraction plate is convex. In certain embodiments, the outer surface of the extraction plate is convex, and the surface of the suppression electrode facing the extraction plate is flat. In certain embodiments, the outer surface of the extraction plate is convex, and the surface of the suppression electrode facing the extraction plate is convex. In some embodiments, the plasma density is greater at the edge of the extraction aperture than at the center of the extraction aperture. In certain embodiments, the outer sur