You can’t cheat physics…

…and neither can I.

So, where have I been? Up to no good, apparently.

Up until now, I have skipped altogether the way I was going to pattern the chips. The thing is, you can either have not super expensive paterning tools and expensive resists, or expensive tools and cheap resists.
Obtaining the expensive resists is, well…expensive, plus they are very especialized and sensitive. Also, the optical setup needed is not an easy task either. While looking into it, I found out that acrylic (PMMA) can be used as resist, however, it requires e-beam paterning, wich in turn means you need an electron microscope, wich is not cheap.

Some countries have kind of a market for secondhand electron microscopes, however mine doesn’t. The thing is, if you don’t actually need to scan the thing, but just to shoot electrons at it, could you use any other electron gun?

In theory, you could. It is not a question of voltage (this paper talks about very low voltage PMMA paterning) but to get the assembly to the adequate vacuum conditions. It is not enough to have a good mechanical vacuum pump.

In case you don’t believe me, here’s what a CRT tube does in 40 microns of Argon vacuum:

Here’s the setup:

Having proven that I needed a High vacuum pump, I started working on an oil diffusion pump.

However, the pieces I practiced on where 0,5mm stainless, wich proven trycky, but doable. The final pieces where only 0,25mm thick, wich, unfortunately, altough possible in short runs, it did pierce the sheet on start, wich left the pieces unusable. Shame, they where looking gorgeous:

Now that I had to start again and spend more money on it, a consensus was reached between me and an expert (to be mentioned when, if he, permits it) to try to go for a turbomolecular pump, wich are quicker to reach and stop vacuum, clean in their operation and they look like miniature turbines, wich, to be frank, turns me on. XD

 

Advertisements