Wednesday, November 25, 2015

Shortcuts to Using Cadence Virtuoso for Layout

These are a few keyboard shortcuts that you may find useful for easy layout practice in Cadence Virtuoso:

Chop = Shift + c
This function is used to delete an arbitrary region of a shape. for example, if you need to split a diffusion rectangle of 100u x 100u into two rectangle of 100u x 40u, or you want to trim a metal shape with respect to the edge of some other shape, you can use this command. For this, you need to select the shape to chop, press shift+c, draw a rectangle that will chop the shape. This will chop the intersecting areas of the selection and object rectangles.

Path = p
This function helps to draw metal or polysilicon areas without using broken rectangles. You will need to know the start of path, bends and end of path points for this. You will press p, then click on start of path, keep clicking at bends, and double click to end path.

One may note that by pressing F3, one can change the thickness of the path by changing the values in the dialog box that appears latter.

Copy in array = c -> F3
Copying in array is useful to draw multiple contacts. For this, you can select the shape to copy, press F3. A dialog box will appear which will show the number of rows and columns required. Also, the spacing in X and Y direction will be shown. Enter these and click in the drawing space. Move the selection first in X direction and click, then Y direction and click. Your array of contacts will be ready. This is useful when you are making a large number of contacts.

Merging abutments = Shift + m
We may draw a metal path from one point to other by aligning a series of rectangles, but this requires more memory when saving large files. Thus, one may merge paths such that abutments turn into a single shape. For this, select the rectangles to merge and press shift + m. This will merge the selected shapes if they exist in the same layer.

Merging can also be done after the whole layout it drawn, or a major part of it is drawn. In that, select all by pressing ctrl + a and then press shift + m.

Align ... to be continued

Group objects