Datatype and Element Attributes
In some file formats additional informations can be stored. For the MEMS/IC design two kinds of informations can be used: datatype (available in GDSII, OASIS) and element attributes (available in GDSII). These information can be view/modified via the Properties Mode. But if not used in the current design, they are hidden. To show it, press the little cross in the lower left corner in each property dialog.
A datatype is a additional number which can be stored which each primitive element (path, box, polygon, text). It is commonly used in two areas. First it is used in e-beam exposure of photo masks. (only in sharp beam system, not in gaussian beam systems) Here a different exposure energy is needed for each element to achieve exact image. The datatype field is used the store the exposure energy. The other application where the datatype is used is an extension of layers. Early layout system had a hard restriction of the amount of layer. To increase the amount of layers the datatype was used. Also it is used for a more exact description of an element. It describes whether the element is part of a conductor, capacitor, ... or just a label. For the last application it may be interesting to split different datatypes on different layers. This is supported by the layout editor. Activate it via the SetupDialog and configure it via the LayerManager.
Beside the datatype each element can have a unlimited number of attributes. Attributes are a combination of a attribute type (normally a number) and a value (a free text). Attributes are also exists for cell reference where are no datatypes are possible. Attributes are rarely used. The LayoutEditor used it to store some information for the netlist driven layout.