Guide to design microfluidic chips


First step: What do you want to do?

Second step: consider the necessary variables to your application

Always keep in mind of dimensions of your platform.
after knowing what material and fabrication methods you would like to use, usually the primary constricting dimension is from either coverslip or glass slides.
keep in mind of dimension so you don't have to scrap hours of chip design down the road.

1. Material

2. Flow

3. microscope

4. temperature


Third step: Start designing

PDMS

General Tips to design microfluidics chip mask

First keep in mind what kind of photoresist you want to use. Negative or positive. What are their properties. 


There are several good software for designing pattern and layouts.
Commonly used software are LinkCAD, Clewin, Coventorware, layouteditor
The important thing is to be capable of exporting GDS files as it is accepted by mask fabrication and also the standard file type for many maskless writer for directing fabricating the mold or fabricating the mask.

I personally like to use AutoCAD and KLayout(freeware) to produce the mask.
Design your design in autocad using only polylines in 2D. 
It is advisable to use the layer feature if you wish to design masks for multilayer microfluidic devices.
save the design into dxf.

Klayout reader options should be configured to merge lines and auto-close open contours for LINE/POLYLINE.

if you started from Autocad iso, the unit in Autocad is in mm. you should set the reader option in klayout to dxf file unit as 1000micron (otherwise small structures will be read wrong with error in spacial dimension which will be amplified when you times 1000 scale during saving to gds)
open the dxf with Klayout and inspect the correctness of the file.
Save as GDSII file (*.gds) so most maskless writer can recognize. (Be sure to input the accurately magnification for the file to match the dimension you designed)
If you have layouteditor or Clewin, you can check the final file of mask.

Tips:
1. To add text that can be visible by klayout, the text must be tranferred into polyline.
insert polyline text using ExpressTools>modifytext>explode
TXTEXP command

Alignment marks
50-100micron

Resources:
1. mask design template and guidelines from Stanford microfluidics foundry.
2.

Thermoplastics

General tips for design thermoplastic chip



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