editor's blog
Subscribe Now

Self-Assembly Shapes

The concept of oil and water separating sounds like an easy way to describe what happens with directed self-assembly. But unfortunately, it’s not quite that simple. All those lines you see so neatly laid out in the microphotographs? That’s not how it always works.

The thing is, oil and water molecules aren’t connected; they’re separate so they can go their separate ways. With diblock copolymers, the two constituents are like oil and water in that they don’t mix, but they’re also covalently bonded to each other. Think of it as two polymers that avoid each other – and yet the end of one is connected to the end of the other. This makes a long chain where one end wants to distance itself from the other.

It’s for this reason, for example, that you can have a triblock copolymer with only two constituents: one of the two isn’t just connected to one end of the other; it’s connected at both ends (like the : P2VP-b-PS-b-P2VP triblock copolymer mentioned in our story on HGST’s hard drive work using DSA and NIL).

As a result, the shapes that result during separation can be more complex because the two (or three) materials can’t get away from each other completely. One common configuration is as horizontal cylinders – like spaghetti or ropes running next to each other. Some even separate into spheres with one material inside and the other coating it.

The shape that’s preferred so far, however, is called a “lamella” (plural “lamellae”). It’s a flat layer. Some materials will self-assemble into horizontal lamellae, which are, of course, of no use for lithography, to make the process easier, experts recommend this good Surface Mount Assembly. Preferred are the materials – like PS-b-PMMA – that organize themselves into perpendicular lamellae, like the grooves in an old-school vinyl record. Unlike the cylindrical ropes, these have straighter sidewalls, looking more like canyons than a bowl of pasta. This is a better way to create the high-fidelity features that can be filled and etched and whatever to transfer a pattern into the underlying silicon (or whatever) substrate.

Leave a Reply

featured blogs
Mar 28, 2023
In this user case, Marintek uses Fidelity Fine/Marine and Hexpress for resistance curve prediction of a planning hull and its validation against the model test cases. Team Involved End User: Eloïse Croonenborghs, Research Scientist at MARINTEK, Maritime division, Trondhe...
Mar 23, 2023
Explore AI chip architecture and learn how AI's requirements and applications shape AI optimized hardware design across processors, memory chips, and more. The post Why AI Requires a New Chip Architecture appeared first on New Horizons for Chip Design....
Mar 10, 2023
A proven guide to enable project managers to successfully take over ongoing projects and get the work done!...

featured video

First CXL 2.0 IP Interoperability Demo with Compliance Tests

Sponsored by Synopsys

In this video, Sr. R&D Engineer Rehan Iqbal, will guide you through Synopsys CXL IP passing compliance tests and demonstrating our seamless interoperability with Teladyne LeCroy Z516 Exerciser. This first-of-its-kind interoperability demo is a testament to Synopsys' commitment to delivering reliable IP solutions.

Learn more about Synopsys CXL here

featured chalk talk

dsPIC33CH DSCs: Two dsPIC33Cs on a Single Chip
Sponsored by Mouser Electronics and Microchip
In this episode of Chalk Talk, Vijay Bapu from Microchip and Amelia Dalton explore the benefits of dual core digital signal controllers. They discuss the key specifications to keep in mind when it comes to single core and dual core DSCs and how you can reduce your development time, save board space and cost and keep the performance and isolation you need with Microchip’s dsPIC33CH DSCs.
Jan 24, 2023
8,861 views