hzeller / gds2vec

A simple program to convert gdsII files to vector output formats. Currently used to create laser-cut models of standard cells.

GDS2VEC

Convert GDS to vector format for visualization and easy conversion to other formats.

Build

Get libgdsii library

sudo apt-get install libgdsii-dev

then

make

Use

Usage: ./gds2vec [options] command <gdsfile>
[Command]
        sky130  : output laser-cut files for sky130 standard cells
        ps      : output postscript of chosen layers
        layers  : show available layers
        desc    : print description of content
[Options]
        -h         : help
        -l <layer[,layer...]> : choose layers (allowed multiple times)
        -o <file>  : output filename (otherwise: stdout)
        -s <scale> : output scale (default: 30000)
        -t <title> : Title on base-plate

Fabrication output

The sky130 command outputs laser cut geometry for all cardboard templates and acrylic cuts needed:

./gds2vec sky130 -t "AND Gate" /tmp/sky130_fd_sc_hd__and4_1.gds > /tmp/layers.ps

If you need DXF for your laser cutter, use the makefile-rule to create it:

make /tmp/layers-1.dxf

Cut annotation

Colors (Layers) in the PostScript/DXF output have different meaning

• Black (RGB: 0, 0, 0): cut line. Just center cut, no kerf consideration.
• Green (RGB: 0, 1, 0): scan engrave on surface e.g. for text
• Cyan (RGB: 0, 1, 1): line engrave on surface
• grey (RGB: 0.8, 0.0, 0.8): comments, fabrication info on bottom.

Materials

For this run below, the following materials and colors were used. For acrylic, ~3mm thickness.

Cardboard

• Cardboard or chipboard: templates to help align the acrylic pieces, and also not 'sticky' if hit with acrylic cement. Should be sturdy and with a thickness <= acrylic thickness.

Acrylic

• Transparent: for back-plane and carrier for the local interconnect support (which is yellow)
• Lightblue: diffusion layer
• Darkgreen: nwell
• Orange: polysilicon
• Yellow: local interconnect
• Red: for VPWR on Metal1 layer
• Dark Blue: for VGND on Metal1 layer
• Smoke grey: for other things on Metal1 layer
• Smoke grey: for via 'pins'. Makes sense to also cut in double thickness material as some of them need to be double thickness.

Fabrication remarks

The last page creates a bunch of pins (about 4x4mm) for the vias. These are cut in two separate DXF layers (horizontal first, followed by vertical) so that parts don't fall through before they are fully cut. Make sure to tell your laser software to cut them in that sequence (typically by switching off cut optimizations).

Some of these pins need to be double the height as they span two layers on glue-up. This can be done by stacking two of them where needed, but it is also a good idea to cut these pins as well with double thick material.

It is useful to create some cardboard templates for alignment while putting things together.

Templates help alignment	Separable

4.7μm Banana for scale	See through view

D-FlipFlop dfxtp-1	Overview	See through view