KLayout Microfluidic Component Library

Parametric PCells for microfluidic chip design — Institut Pierre-Gilles de Gennes (IPGG)

A KLayout library of parametric microfluidic components for soft-lithography mask design. All components are implemented as PCells (Parametric Cells) editable directly in the KLayout GUI, with geometry output as DPolygon for boolean compatibility.

Repo: https://github.com/FattaccioliLab/klayout-microfluidic-components
License: CC BY 4.0 — Jacques Fattaccioli, Institut Pierre-Gilles de Gennes / ENS / Sorbonne Université / CNRS

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Contents

microfluidic-klayout-lib/
├── microfluidic_lib.lym        # Main library — 8 PCells (autoload)
├── cutting_marks.lym           # Cutting marks macro (Tools menu, Shift+C)
├── new_wafer_template.lym      # New layout template (Tools menu, Ctrl+Shift+N)
├── microfluidic.lyp            # Layer colour palette
└── microfluidic_template.py    # Standalone script template

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Installation

Requirements

• KLayout ≥ 0.27
• No external Python dependencies (uses KLayout's built-in pya)

Steps

1. Clone or download this repository:

   git clone https://github.com/FattaccioliLab/klayout-microfluidic-components.git

2. Copy the library files to your KLayout macros folder:

   OS	Path
   macOS / Linux	~/.klayout/pymacros/
   Windows	%APPDATA%\KLayout\pymacros\

   Copy all files from MicrofluidicLib_v3/ into that folder:

   cp MicrofluidicLib_v3/* ~/.klayout/pymacros/

3. Restart KLayout. The library auto-registers on startup.

4. Verify the library is loaded: open the Library Browser (View > Library Browser) and check that MicrofluidicLib appears in the list.

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Starting a new layout

Run the wafer template macro: Tools > New microfluidic layout (or Ctrl+Shift+N).

This creates a pre-configured layout with:

• 4" wafer outline + flat (layer wafer_outline 99/0)
• 5" square mask footprint — 127 × 127 mm (layer masque 20/0)
• Reference outlines to the right of the mask (layer outlines 30/0):
  • 60 × 60 mm chip area
  • 15 × 15 mm cover slip
  • 26 × 76 mm glass slide (vertical)
• Layer colour palette (microfluidic.lyp) loaded automatically
• Full hierarchy expanded, Library Browser opened on MicrofluidicLib

Your working layer for channel geometry is PDMS_channel (1/0).

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Components

All components are available in View > Library Browser > MicrofluidicLib. Drag and drop onto the canvas, then double-click to edit parameters.

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Serpentine Channel

SerpentineChannel

Centred serpentine with guaranteed inlet/outlet alignment. The solver adjusts total length by at most ~2% to ensure legs sit exactly at EXT_WIDTH/2.

Parameter	Description	Default
total_length	Total centreline length (µm)	10 000
channel_width	Channel width (µm)	50
pitch	Centreline-to-centreline pitch (µm)	150
ext_width	External footprint width (µm)	1 000
vertical_leg	Inlet/outlet leg length (µm)	250
n_arc	Arc segments per 180° turn	32

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Straight Channel

StraightChannel

Simple rectangular channel with arbitrary orientation.

Parameter	Description	Default
length	Length along centreline (µm)	1 000
width	Channel width (µm)	50
angle_deg	Angle CCW from +x axis (°)	0

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T-Junction

TJunction

Asymmetric T-junction. The three arms are merged into a single polygon via EdgeProcessor.

Parameter	Description	Default
w_main	Main channel width (µm)	100
w_top	Lateral arm width (µm)	50
l_left	Left arm length (µm)	400
l_right	Right arm length (µm)	500
l_top	Top arm length (µm)	400

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Y-Channel

YChannel

Y-junction with independently adjustable inlet angles and widths. Inner walls intersect at an exact chevron tip (no gap, no overlap). Junction centre at origin; flow exits along +x.

Parameter	Description	Default
theta_deg	Half-angle between inlet arms and horizontal (°)	30
w_upper	Upper inlet width (µm)	80
w_lower	Lower inlet width (µm)	80
w_outlet	Outlet width (µm)	150
l_upper	Upper inlet length (µm)	400
l_lower	Lower inlet length (µm)	400
l_outlet	Outlet length (µm)	500

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Flow-Focusing Junction (simple)

FFSimpleJunction

Simple cross-junction (4 rectangular arms, merged). All four arm widths and lengths are independent. Suitable for flow-focusing with symmetric sheath arms.

Parameter	Description	Default
w_top / w_bottom	Dispersed-phase arm widths (µm)	50
w_left / w_right	Continuous-phase arm widths (µm)	200
l_top / l_bottom / l_left / l_right	Arm lengths (µm)	400

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Flow-Focusing X-Junction

FFXJunction

X-junction with re-entrant orifice geometry. The central rectangle is constrained by the crossing arm widths (not by the arm's own width), which correctly models the pinch-off geometry of a flow-focusing device.

Parameter	Description	Default
w_top / w_bottom	Dispersed-phase arm widths (µm)	50
w_left	Continuous-phase inlet width (µm)	100
w_right	Outlet width (µm)	150
l_top / l_bottom / l_left / l_right	Arm lengths (µm)	400 / 400 / 1000 / 400

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Chamber

Chamber

Rectangular chamber with independent chamfers on left and right ends, defined by the length of the non-chamfered vertical edge (l_left, l_right). Setting l_left = l_right = height gives a plain rectangle.

Parameter	Description	Default
width	Total width (µm)	2 000
height	Total height (µm)	600
l_left	Left vertical edge length (µm)	200
l_right	Right vertical edge length (µm)	200

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Outlet (radial inlet array)

Outlet

Circular reservoir with an array of trapezoidal punching guides distributed over a configurable angular span.

Parameter	Description	Default
radius	Circle radius (µm)	500
n_inlets	Number of trapezoids	8
angle_start / angle_end	Angular span (°)	0 / 180
w_inner / w_outer	Trapezoid inner/outer width (µm)	200 / 400
l_trap	Trapezoid radial length (µm)	500
gap	Radial gap between circle and trapezoid (µm)	100

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Cutting Marks macro

The cutting marks macro inserts L-shaped corner marks for dicing. It is a standalone macro, not a PCell, because its geometry depends on the bounding box of existing shapes.

Run it: Tools menu → Cutting Marks (or Shift+C)

Behaviour:

• If objects are selected, marks are placed around their combined bounding box.
• If nothing is selected, the full cell bounding box is used.

Parameters (edit at the top of cutting_marks.lym):

Parameter	Description	Default
MARGIN	Distance from chip bbox to corner (µm)	2 000
MARK_LENGTH	Arm length of the L (µm)	500
MARK_WIDTH	Line width of the L (µm)	50
LAYER_INFO	Output layer	10/0

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File format notes

• All geometry is output as DPolygon (integer polygon after to_itype(dbu)), compatible with boolean operations via EdgeProcessor.
• Default DBU is 0.001 µm (1 nm resolution).
• The serpentine uses DPath.polygon() for arc-to-polygon conversion with flat endcaps (bgn_ext = end_ext = 0).

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Todo / known limitations

• Rounded corners — optional fillet radius on channel junctions (reduces stress concentration in PDMS)
• Connector ports — named snap points at each arm end for automated chip assembly
• Y-channel with divider wall — variant with a central wall separating the two inlet streams into the outlet
• Meander resistor — compact resistance channel with configurable number of turns and turn geometry
• Via / inlet pad — circular pad with optional reservoir ring, suitable for punching guides
• Salt package — publish to KLayout's built-in package manager for one-click install
• GDS test file — reference layout with one instance of every component at default parameters
• DXF export workflow — documented procedure for sending to clean-room mask writers

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Citation

If you use this library in published work, please cite:

J. Fattaccioli, KLayout Microfluidic Component Library, Institut Pierre-Gilles de Gennes, 2025.
https://github.com/FattaccioliLab/klayout-microfluidic-components — CC BY 4.0