editor's blog
Subscribe Now

A Place to Dry Your Nanoclothes

The next thing after MEMS is… OK, time’s up… NEMS. Of course. From micro to nano.

One of the materials that seems inextricably linked to NEMS is carbon, even if carbon isn’t a defining element of NEMS. More explicitly, at UC Irvine, they’re doing work on what Prof. Marc Madou calls Carbon-MEMS (or C-MEMS).

Manufacturing techniques at the nano level can be quite different from what we’re used in at the MEMS level. C-MEMS uses organic precursor chemicals to lay down a structure. When processed/heated, these structures lose 80% or more of their volume and reduce to almost pure glassy carbon. This presents an attractive alternative to trying to actually machine carbon, which is notoriously difficult.

At the recent MEMS Business Forum, Prof. Madou illustrated one type of structure his team has worked on called a “wash-line nanosensor.” These consist of a series of carbon posts; wires are then strung from post to post (like a wash-line) above whatever the substrate below is. This makes the wire accessible from all sides and distances it from any effects the substrate might have on it.

But how to make such a structure?

The posts can be made by layering an appropriate photoresist polymer down, patterning and exposing it to create the posts, and then reducing those polymer posts to glassy carbon. Step 1 done.

He showed that, given the right polymer goop, discharged through a syringe or nozzle in the presence of a voltage between the nozzle and substrate, you can “spin” a thin bead of the material which, on its own, just kind of mats up like spaghetti on a plate. They refer to this as “electro-spinning.”

Done in the presence of the posts, and spraying for 2-3 seconds, they found that the extruded polymer thread would naturally start at one post, swirl around a bit, then drift to the next post, swirl some more, etc. The spaghetti cap on each post made ohmic contact, but they wanted something not quite as messy.

So they moved the substrate with the posts a bit closer to the nozzle and then moved the stage on which it was held. Rather than the thread going where it wanted, they could direct the thread from post to post in a controlled manner, with each thread making a clean, simple connection on the top of each post.

There’s lots of magic here in the materials and viscosities and all of the other parameters involved. But, stepping back from all of that, it represents a dramatically different way of building an electromechanical structure.

Leave a Reply

featured blogs
Aug 18, 2018
Once upon a time, the Santa Clara Valley was called the Valley of Heart'€™s Delight; the main industry was growing prunes; and there were orchards filled with apricot and cherry trees all over the place. Then in 1955, a future Nobel Prize winner named William Shockley moved...
Aug 17, 2018
Samtec’s growing portfolio of high-performance Silicon-to-Silicon'„¢ Applications Solutions answer the design challenges of routing 56 Gbps signals through a system. However, finding the ideal solution in a single-click probably is an obstacle. Samtec last updated the...
Aug 17, 2018
If you read my post Who Put the Silicon in Silicon Valley? then you know my conclusion: Let's go with Shockley. He invented the transistor, came here, hired a bunch of young PhDs, and sent them out (by accident, not design) to create the companies, that created the compa...
Aug 16, 2018
All of the little details were squared up when the check-plots came out for "final" review. Those same preliminary files were shared with the fab and assembly units and, of course, the vendors have c...
Jul 30, 2018
As discussed in part 1 of this blog post, each instance of an Achronix Speedcore eFPGA in your ASIC or SoC design must be configured after the system powers up because Speedcore eFPGAs employ nonvolatile SRAM technology to store its configuration bits. The time required to pr...