Mask export

Masks are defined by simple scripts, which define the layout of chips in the mask and the parameters of those chips. These scripts will export .oas/.gds files required for photomask production and possibly EBL, as well as auxiliary files such as netlists, images and automatic mask documentation. There are three ways to run the mask scripts:

• From the KLayout macro editor.

• In KLayout from the command line using klayout -z -r ./scripts/masks/maskname.py.

• As standalone python script. In this case, mask generation always runs single threaded.

Tutorial

Basic mask script and export

1. Launch KLayout Editor and open the Macro IDE (F5).

2. Add the following script to the kqcircuits_scripts/masks folder in the Python tab of the Macro IDE:

   # Imports required for any mask
   from kqcircuits.masks.mask_set import MaskSet
   # Import chips required for this mask
   from kqcircuits.chips.demo import Demo
   
   
   # Initialize mask object.
   # "name" and "version" will be displayed in labels inside the mask
   # and in the names of the exported files.
   # "with_grid" determines if the ground plane grid is created.
   test_mask = MaskSet(name="Test", version=1, with_grid=False)
   
   # Add mask layouts.
   # A mask layout determines which chip is at each position. The chips are
   # identified by strings which are defined by the `add_chip()` calls
   # below. "---" denotes places without a chip.
   test_mask.add_mask_layout([
       ["---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---"],
       ["---", "---", "---", "---", "---", "DE1", "DE1", "DE1", "DE1", "DE1", "---", "---", "---", "---", "---"],
       ["---", "---", "---", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "---", "---", "---"],
       ["---", "---", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "---", "---"],
       ["---", "---", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "---", "---"],
       ["---", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "---"],
       ["---", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "---"],
       ["---", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "---"],
       ["---", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "---"],
       ["---", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "---"],
       ["---", "---", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "---", "---"],
       ["---", "---", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "---", "---"],
       ["---", "---", "---", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "DE1", "---", "---", "---"],
       ["---", "---", "---", "---", "---", "DE1", "DE1", "DE1", "DE1", "DE1", "---", "---", "---", "---", "---"],
       ["---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---"],
   ])
   
   # Chip definitions
   test_mask.add_chip(Demo, "DE1")
   
   # Build the mask.
   # This generates the layout in KLayout based on previous calls to
   # ``add_mask_layout()`` and ``add_chip()`.
   test_mask.build()
   # Export the mask files to TMP_PATH, unless an ``export_path`` argument has been given to MaskSet.
   test_mask.export()
   

   Any mask script should follow roughly the same structure. The beginning and end of the script (creating the MaskSet object, and exporting the mask) are generally the same for any mask.

3. (Optional) Open kqcircuits_scripts/macros/logging_setup and run it. This makes mask generation logs visible in the Macro console.

4. With the mask script open, click “Run script from current tab” (Shift+F5). This generates the mask and exports the files to the folder defined by kqcircuits.default.TMP_PATH or to any directory spcified by the export_path argument to MaskSet.

If you generate the mask again (for example in the following sections), it is recommended that you first close the layout where the previous mask was generated.

Ground grid

The generated masks can include a ground plane grid, which automatically avoids other elements. To generate it, use with_grid=True in the mask object initialization:

test_mask = MaskSet(name="Test", version=1, with_grid=True)

Because the grid generation is slow, it is recommended to keep with_grid=False when testing masks, and only use with_grid=True for masks that are really produced.

Adding and modifying chips

1. Add the following lines to the imports section of the script:

   from kqcircuits.chips.demo_twoface import DemoTwoface
   from kqcircuits.chips.quality_factor import QualityFactor
   

2. Add the new chips:

   test_mask.add_chip(DemoTwoface, "DT1")
   test_mask.add_chip(QualityFactor, "QF1")
   

3. Add a new variant of the demo chip with different parameters:

   test_mask.add_chip(Demo, "DE2", include_couplers=False, readout_res_lengths=[5400, 5500, 5600, 5700])
   

4. Replace some of the “DE1” entries in the mask layout by “DT1”, “QF1” and “DE2”. This will determine where those chips are placed in the mask.

5. Generate the mask. You should see the new chip variants at the positions defined in the previous step.

Multi-face masks

The mask generated in the previous step contained “DemoTwoface” chips, which are supposed to have elements in two different chip faces for a flip-chip process. However, the generated mask only contained the parts in “1t1”-face. To generate mask for also “2b1”-face chips, we need to add an additional mask_layout

1. Add the following below the old add_mask_layout() call:

   test_mask.add_mask_layout([
       ["---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---"],
       ["---", "---", "---", "---", "---", "---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---", "---", "---", "---", "---", "---"],
       ["---", "---", "---", "---", "---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---", "---", "---", "---", "---"],
       ["---", "---", "---", "---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---", "---", "---", "---"],
       ["---", "---", "---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---", "---", "---"],
       ["---", "---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---", "---"],
       ["---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---"],
       ["---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---"],
       ["---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---"],
       ["---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---"],
       ["---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---"],
       ["---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---"],
       ["---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---"],
       ["---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---"],
       ["---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---"],
       ["---", "---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---", "---"],
       ["---", "---", "---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---", "---", "---"],
       ["---", "---", "---", "---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---", "---", "---", "---"],
       ["---", "---", "---", "---", "---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---", "---", "---", "---", "---"],
       ["---", "---", "---", "---", "---", "---", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "DT1", "---", "---", "---", "---", "---", "---"],
       ["---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---", "---"],
   ], "2b1")
   

   Notice the “2b1” argument after the actual mask layout. This means that only elements which are in chip face “2b1” will be included in this mask layout. By default, the mask layout will use elements in chip face “1t1”, which is the case for the first mask layout in this script.

2. Generate the mask. In KLayout cell hierarchy, you should see both “Test 1t1” and “Test 2b1” cells. You can right click them and select “Show as new top” to verify that “Test 1t1” contains the parts of DemoTwoface in “1t1”-face and “Test 2b1” contains the parts of DemoTwoface in “2b1”-face (with proper mirroring and rotation).