CAD for Microfabrication using LayoutEditor


The purpose of CAD in this context is to define which areas will be exposed during a lithography step and which areas will be left unexposed. For our purposes, there are two primary paths your data will follow once it leaves the CAD system:
  • Sent to a mask making machine to generate a photomask you’ll use for a photolithography step. This might be the WNF's Heidelberg mask maker, or it might be an outside service such as FineLine or PhotoSciences. Each of these cases, as well as any other mask vendor, has a specific set of do's and don’ts for their system, dictated by the manufacturing tools and software they use, and the capabilities of their process.

  • Sent to the JEOL JBX-6300 E-Beam Lithography system for direct-writing on wafer. In this case, the data will be processed through a sophisticated software program called BEAMER (formerly LayoutBEAMER), from Genisys GMBH. Since this is my primary arena, I’m going to focus on EBL exposures, but I’ll mention mask shops at various points in this discussion as well.

Microfabrication CAD is complicated; there are lots of tools and lots of options within those tools. It will take time to learn the basics of CAD, the tool you're using, and which features to use to achieve your layout goal efficiently and effectively. The tutorial here tries to give you both background and some specifics on the LayoutEditor tool, and then goes on to provide some specific design details for e-beam designs.

There are some good introductions to LayoutEditor found on the official site at this page: http://www.layouteditor.net/wiki/CategoryTutorial
You might find these more useful, especially if you're already familiar with microfabrication CAD from some other context and just need to learn about the program itself.
But if you're completely new to CAD, you might find especially the first page below, Principles, provides useful & necessary background.


Tutorial



This tutorial is focused on implementing smart design principles using the LayoutEditor software. (A similar tutorial is also available specifically for KLayout.) The WNF maintains a site license for UW personnel for use on UW computers; more about our site license here.

There are certainly other software packages out there, such as the freeware KLayout, as well as very complex, expensive systems. Many of the principles remain the same, because pretty much all available systems use the same data format for interchange. There's a discussion of data formats here. The one particular item of note is that some types of 3-D cad systems are generally not well-suited to the type of microfabrication layouts that we do. In particular, AutoCAD and SolidWorks are not generally very useful, and very often, trying to use one of these programs will result in more errors and headaches than learning to use one of the correct tools for the job.


This tutorial is divided into several pages: