Search

US-12622191-B2 - Method for ion implantation that adjusts a target's tilt angle based on a distribution of ejected ions from a target

US12622191B2US 12622191 B2US12622191 B2US 12622191B2US-12622191-B2

Abstract

The present disclosure describes a system and a method for an ion implantation (IMP) process. The system includes an ion implanter configured to scan an ion beam over a target for a range of angles, a tilting mechanism configured to support and tilt the target, an ion-collecting device configured to collect a distribution and a number of ejected ions from the ion beam scan over the target, and a control unit configured to adjust a tilt angle based on a correction angle determined based on the distribution and number of ejected ions.

Inventors

  • Chun-Jung Huang
  • Li-Hsin CHU
  • Po-Feng Tsai
  • Henry Peng
  • Kuang Huan Hsu
  • Tsung Wei Chen
  • Yung-Lin Hsu

Assignees

  • TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD.

Dates

Publication Date
20260505
Application Date
20240625

Claims (20)

  1. 1 . A method, comprising: scanning a target with an ion beam, wherein the target is disposed on a moveable tilt stage; collecting ion data comprising a distribution and a number of ejected ions from the target; determining a correction angle based on the ion data; and adjusting a tilt angle of the moveable tilt stage based on the correction angle.
  2. 2 . The method of claim 1 , further comprising scanning the target with the ion beam at a range of angles.
  3. 3 . The method of claim 2 , further comprising scanning the ion beam over the target for a plurality of angle sub-ranges within the range of angles.
  4. 4 . The method of claim 2 , further comprising determining the correction angle based on a weighted sum of a percentage of ions distributed in the range of angles and an average angle of the range of angles.
  5. 5 . The method of claim 2 , further comprising adjusting an ion implantation depth.
  6. 6 . The method of claim 1 , further comprising determining a species of the ejected ions.
  7. 7 . The method of claim 1 , further comprising communicating to the moveable tilt stage, a control signal comprising data and commands for adjusting the tilt angle.
  8. 8 . The method of claim 1 , wherein adjusting a tilt angle comprises adjusting the tilt angle based on the ion data until a minimum number of the ejected ions are collected and recorded.
  9. 9 . The method of claim 1 , further comprising adding the correction angle to the tilt angle in response to the correction angle being a positive value.
  10. 10 . The method of claim 1 , further comprising subtracting the correction angle from the tilt angle in response to the correction angle being a negative value.
  11. 11 . A method, comprising: implanting ions into a target; collecting ejected ions from the target; determining a correction angle based on a distribution and a number of collected ions; and determining an adjusted dosage of the ions and an adjusted tilt angle for the target.
  12. 12 . The method of claim 11 , further comprising determining a distribution, a species, and a number of the ejected ions from the target.
  13. 13 . The method of claim 11 , further comprising adjusting the tilt angle of the target based on the correction angle.
  14. 14 . The method of claim 11 , further comprising adjusting an ion implantation depth.
  15. 15 . The method of claim 11 , further comprising irradiating a second target with an ion beam at the adjusted tilt angle.
  16. 16 . A method, comprising: implanting ions into a target; collecting ion data comprising a distribution and a number of ejected ions from the target; determining, based on the distribution and the number of the ejected ions, an adjusted dosage of the ions and a correction angle for the target; and adjusting the target based on the correction angle.
  17. 17 . The method of claim 16 , wherein adjusting the target based on the correction angle comprises adjusting a tilt angle of the target.
  18. 18 . The method of claim 17 , wherein adjusting the tilt angle comprises adjusting the tilt angle based on the ion data until a minimum number of the ejected ions are collected and recorded.
  19. 19 . The method of claim 16 , further comprising adjusting an ion implantation depth.
  20. 20 . The method of claim 16 , further comprising determining a species of the ejected ions.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. Non-provisional patent application Ser. No. 18/126,861 titled “Method for Ion Implantation that Adjusts a Target's Tilt Angle Based on a Distribution of Ejected Ions From a Target,” filed on Mar. 27, 2023, which is a continuation of U.S. Non-provisional patent application Ser. No. 17/529,504 titled “Method for Ion Implantation that Adjusts a Target's Tilt Angle Based on a Distribution of Ejected Ions from a Target,” filed on Nov. 18, 2021, which is a divisional of U.S. Non-provisional patent application Ser. No. 16/381,863, titled “Method for Ion Implantation that Adjusts a Target's Tilt Angle Based on a Distribution of Ejected Ions from a Target,” filed on Apr. 11, 2019, which claims priority to and the benefit of U.S. Provisional Patent Application No. 62/752,268, titled “Ion Implantation Apparatus and Method,” filed on Oct. 29, 2018. The entire contents of the aforementioned applications are incorporated by reference herein in their entireties. BACKGROUND Ion implantation (IMP) is widely used in semiconductor fabrication for creating regions of various dopant concentrations/levels. In an IMP process, ions are accelerated to bombard a solid target (e.g., substrate or film), thereby changing the properties (e.g., physical, chemical, and/or electrical properties) of the target. For example, in a complementary metal-oxide semiconductor (CMOS) device, regions of different dopant concentrations can be formed by IMP. Ions can be accelerated to impinge the target from various directions, depending on, e.g., the shape and the depth of the doped region. For example, ions can be implanted into the target at an implantation angle theta (θ, the angle between the target surface normal and the ion beam) and a suitable energy so the ions can be implanted within a desired depth/location range. BRIEF DESCRIPTION OF THE DRAWINGS Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the common practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of illustration and discussion. FIG. 1 illustrates an IMP process. FIG. 2 illustrates an IMP apparatus, according to some embodiments of the present disclosure. FIG. 3 illustrates an IMP system, according to some embodiments of the present disclosure. FIG. 4A illustrates an ion distribution recorded by the ion implantation system, according to some embodiments of the present disclosure. FIG. 4B illustrates a histogram of the ion distribution of FIG. 4A. FIG. 5 illustrates a method for performing an IMP process, according to some embodiments of the present disclosure. FIG. 6 illustrates a method for optimizing IMP parameters, according to some embodiments of the present disclosure. FIG. 7 illustrates an exemplary computer system for implementing various embodiments of the present disclosure. DETAILED DESCRIPTION The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are merely examples and are not intended to be limiting. In addition, the present disclosure repeats reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and, unless indicated otherwise, does not in itself dictate a relationship between the various embodiments and/or configurations discussed. The term “about” as used herein indicates the value of a given quantity that can vary based on a particular technology node associated with the subject semiconductor device. In some embodiments, based on the particular technology node, the term “about” can indicate a value of a given quantity that varies within, for example, 5-30% of the value (e.g., ±5%, ±10%, ±20%, or ±30% of the value). Ion implantation is widely used in semiconductor fabrication to form regions doped with desired ions (in a device or structure) to alter the chemical, physical, and/or electrical properties of the regions. In an IMP process, accelerated ions impinge a region of a substrate so these ions can be implanted into the substrate as dopants at desired locations/depths. These dopants can enable the device or structure to have desired properties, which are essential for various applications. For example, source and drain regions of a CMOS device are doped with dopants that have an opposite polarity than the substrate, and allow the CMOS device to be turned on and off with a gate voltage. The source and drain regions can be formed by performing IMPs on the substrate. In an IMP process, ions can be implanted into the substrate at a tilt angle of, e.g., about 0 degrees to about 15 degrees. T