FIB Step Settings

Specific settings for a FIB type step, which provides options for milling with the ion beam.

Some intro text, image vs mill settings, do not need to be the same

Image Settings

FIB steps have an internal set of imaging settings that follows the same convention as a standard image. This image is collected prior to any patterning or milling. Please see here for more information on Image Settings. If you do not need to mill with ion beam and only want to take an image, use an image type step instead. For FIB type steps, the image will always be taken with the ion beam.

mill

FIB milling settings contain nested mappings for the beam settings and pattern settings.

beam

Beam settings follow the same conventions as described in beam settings. This allows the user to change various settings between the image and pattern, such as using a lower accelerating voltage or beam current for ion imaging and a higher beam current and/or voltage for the actual milling operation.

Although the user has the option to change other settings such as the horizontal field width (magnification) between imaging and milling, it is generally recommended to keep this value constant. As with the imaging operation in a FIB step type, only an ion beam can be used for patterning for these milling operations, which also means dynamic focus and tilt correction are not accessible for this data type. Users should also note that any scan rotation applied from the imaging settings in a FIB step type will be maintained when the milling pattern is placed, so care should be taken to ensure the patterning settings are determined at the same scanning conditions.

pattern

Patterning settings for the ion beam contain various nested mappings depending on the type of patterning desired.

  • application_file (str): The application file preset, a string. All pattern types require the use of a preset recipe that controls various low-level settings of patterning such as overlap of adjacent pixels, dwell time, defocus, and blur. Nearly all microscopes will come with a variety of default recipes, including Si and Al, but many users also develop and create their own recipes. Any custom application files created by the user should be saved in the same directory location as the default application files in order to be accessed by this tool.

When using the GUI, a dynamic list of the available application files for your particular system will automatically be generated. When not using the GUI, users can determine this list themselves by running the following python script:

import pytribeam.types as tbt
import pytribeam.utilities as ut
import pytribeam.factory as factory

# define parameters for your specific microscope connection
connection_host = "localhost" # a string or NoneType
connection_port = None # a string or NoneType

# create the microscope object and connect to it
microscope = tbt.Microscope()
ut.connect_microscope(
    microscope=microscope,
    connection_host=connection_host,
    connection_port=connection_port,
)

# determine what application files are available on this connection
found_application_files = factory.active_fib_applications(
    microscope=microscope
) # returns a list
print("Found the following application files:")
for item in found_application_files:
    print(f"\t{item}")

type

There are currently supported pattern types, which must be an enumerated member of the FIBPatternType* class in the types module. Currently supported pattern types include:

  • rectangle: A rectangle pattern type.
  • regular_cross_section: A regular cross-section pattern type.
  • cleaning_cross_section: A cleaning cross-section pattern type.
  • selected_area: Specialty functionality requiring some python scripting knoweldge to make arbitrary scan geometries. Details on usage can be found here

Settings for one and only one pattern type are supported for a given FIB step. If more complex milling geometries are desired, please see the section on theselected_area pattern type.

The rectangle, regular_cross_section and cleaning_cross_section pattern types all have the same set of parameters, namely:

  • center: The center of the pattern using the Patterning coorindate system.

    • x_um (float): location of the pattern center along the x-axis in microns, a float.
    • y_um (float): location of the pattern center along the y-axis in microns, a float.

  • width_um (float): The width of the pattern along the x-axis in microns, a float.

  • height_um (float): The height of the pattern along y-axis in microns, a float.

  • depth_um (float): The depth of the pattern along z-axis (into the sample) in microns, a float.

  • scan_direction (str): The scan direction controls the direction of scanning of box type patterns, which includes rectangle, regular_cross_section and cleaning_cross_Section patterns. The scan_direction must be an enumerated value in the FIBPatternScanDirection class in the types module. Currently supported values include:

    • BottomToTop
    • TopToBottom
    • LeftToRight
    • RightToLeft
    • DynamicTopToBottom
    • DynamicAllDirections
    • DynamicLeftToRight

  • scan_type (str): Controls the sequence of points scanned in combination with the scan_direction parameter. Must be a member of the FIPatternScanType enum class defined in the types module. Currently supported values include:

    • Serpentine: Reverse direction (left-to-right switch to right-to-left, or top-to-bottom switches to bottom-to-top) on every subsequent line.
    • Raster: Repeat the patterning direction (left-to-right, bottom-to-top, etc.) on every line.