Exposure settings

The exposure settings are divided into two groups:

  • Common Exposure Settings
  • Per Structure Exposure Settings

Common Exposure Settings

This settings define the defaults for all elements/structures in a task.

Note

A short reference of all common exposure settings can be found in the ExposureSettings node reference.

Basic settings

These settings must be specified.

Target Dose

resistSensitivity (⇨ double)   plug_in plug_out , f_default 300

This is the “flat dose”, that is applied during exposure. This value is a property of your resist. It can be usually found in the data sheet of the resist specifications. The unit of this value is As/cm^2.

Beam current

beamCurrent (⇨ double)   plug_in plug_out , f_default 100

Beam current. This should be measured with the SEM (if supported), or an external measurement device and specified here. If the SEM, or the smile2 SEM component, support current reading, the tool button on the right side of the current input field is enabled, and can be used to initiate current reading. The current is specified in units of pA.

Note

Current measurement should happen on the place where the Faraday cup is located (and in beam spot mode).

Warning

Make sure that the beam blanker is off (the beam is on), before measuring the current.

Extended settings

Sorting
Sometimes, the order how individual elements are exposed can be important. These settings offer some control on ordering (or sorting) of structure elements before exposure. More information can be found in the Sorting chapter.
Stitching
Stitching can be used to write a ‘big’ structure as an array of smaller structures (big and small by means of the write field size), in order to improve accuracy. For more information on stitching, read the Stitching chapter.
Exposure Event Handlers

Exposure Event Handlers are customized software elements (that can be created with Python). These handlers are called during the exposure process and can react on certain events (eg. stage has arrived destination position). Exposure Event Handlers can be used to

  • Customize exposure settings,
  • Enable or disable certain structure elements,
  • Programmatically add, remove or modify structure elements (eg. creating an additional label for each structure).
  • Modifying the alignment matrix (or performing automatic alignment. See: AutoAlignHandler for an example).
  • Reposition the stage.

More information about Exposure Event Handlers can be found in the Exposure Event Handlers chapter.

Focus Interpolation

Especially for large structures, any (slight) tilt of the wafer can destroy the focus if the stage moves far away from where the focus has been set up.

Focus interpolation addresses this issue. If enabled, an arbitrary (but at least three) amount of (<stage position>,focus) pairs can be recorded. During exposure, this data is used to adjust the focus at any point on the stage, based on linear interpolation of the recorded data.

Note

We introduced a new Adaptive multilevel B-Spline interpolation mode (see: [1] ). This mode is intended to produce improved results, However it is considered to be experimental in the current release.

Task Element Settings

_images/per_structure_settings.png

The settings for selected element(s) are located in the attribute editor, and divided in several sections (tabs).

A documentation of the task element settings can be found in the Exposure Task Element, and in the Scan Task Element reference.

Hint

If more than one element is selected, the attribute editor shows only the properties of the acive element. However, if you change a property, the chage is propagated to all selected elements (that actually have this property/plug).