91–100 of 136 posts
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How does microgravity help in nanofabrication?
It may not be the microgravity that's the major help, but the hard vacuum. Deep space is the biggest, best clean room there could ever be.
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Ok thanks for that. So 500 nm today, moving to 250 nm by the end of the year or early next year. So your 12.5mm wafer can have a 8.8 x 8.8 mm square inside of it, or 78.125 mm^2. If I did the math right that is on the order of 156M transistors given a 4t ram cell that is about 39 million bits of RAM. So basically a pretty useful amount of space for "jelly bean" type applications. A synchronized fab line with a median…
Here is a PDF from 2017 from someone involved with a project wich seems to intend to use this in an (large scale?) innovation initiative in Japan. [1] www.lip6.fr/public/2017-03-17_Shimizu.pdf Mentioned are workflows, used tools, intendend audience and goals, estimated prices, nda-freeness of spice models and design rule check, open source, open-cores, github, and so on. If they really make this widely available, the…
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pretty easy really. Add acid to water, then add baking soda to the acidic water until it's neutralized. (no more bubbling), then pour it down the sink with more water. Use appropriate precautions, gloves, goggles, well-ventilated area, etc. Once the acid is neutral, it won't hurt anything in the pipes.
But is it acceptable to dump wastewater with Cu+/Cl- ions inside? I've read that according to some regulations in some areas, they are considered pollutants and should not be dumped directly to the drainage. Or is it something you can just ignore, because at the end of the day everything goes to a wastewater treatment plant, and your volume/concentration is too low to be considered hazardous, and actually not more ha…
https://www.mgchemicals.com/products/prototyping-and-circuit...
> The solution must not be put down the drain because of residual copper ions left in it. To make it safe for disposal, you can add sodium carbonate (washing soda) or sodium hydroxide to it to neutralize it, until the pH value goes up to between 7.0 and 8.0, testing it with indicator paper. Copper will be deposited as a sludge. Allow the sludge to settle, pour off the liquid, further dilute it with water and then it can be poured down the drain. Collect the sludge in plastic bags and dispose of it as required by your local waste authority.
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>"You're referring to the fact that the edges aren't really sharp and are kind of 'soft', right? Like, everything isn't 90 degree angles and is kinda rippley in places?" Yes to both of these questions. "Soft" is probably a better way to articulate this, thanks. I'm not following the explanation of this being caused by photography however. Is this specific to photography at this scale? >"I imagine if you were to make…
By photography, I meant the photolithography, as you mentioned to another replier. This inherently will cause softness as described since there's always going to be light leakage and the masks you use will never be truly perfect. Given the sizes though, they're pretty damn good. As for 'modern tech' vs. old tech, I'm referring to if you made the same size silicon structure on newer tech. When you get down to 7nm or w…
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pretty easy really. Add acid to water, then add baking soda to the acidic water until it's neutralized. (no more bubbling), then pour it down the sink with more water. Use appropriate precautions, gloves, goggles, well-ventilated area, etc. Once the acid is neutral, it won't hurt anything in the pipes.
But is it acceptable to dump wastewater with Cu+/Cl- ions inside? I've read that according to some regulations in some areas, they are considered pollutants and should not be dumped directly to the drainage. Or is it something you can just ignore, because at the end of the day everything goes to a wastewater treatment plant, and your volume/concentration is too low to be considered hazardous, and actually not more ha…
Cu though is an aquatic herbicide (used to rid decorative ponds of all plant life including algae) and can mess up things.
> at the end of the day everything goes to a wastewater treatment plant
Some of these things, especially the photosensitive chemicals in particular ammonium dichromate will annihilate the wastewater treatment plant. Experienced this problem in an industrial context once, resulting in tens of millions of dollars in damages to taxpayers and a giant fiasco. As a result our privileges to use the municipal sewage system were withdrawn and we had to spend tens of millions in evaporation towers since no water could leave our facility ever again.
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Cl ions are fine; dissolved table salt consists of them, plus some cations. The copper is more of a problem, and I don't know the official answer. I'd think that if you could oxidize it to copper monosulfide (covellite), cupric oxide (tenorite), or even fully hydrated copper carbonate (malachite) if you don't have acid rain, that would adequately protect it from weathering and thus allow you to dispose of it safely.…
First warning with neutralizing acids: You're going to release a lot of heat, make sure you have a large thermal mass to absorb it. Someone else mentioned mixing your ingredients with water first. This is why. From what I understand the last thing you want to experience is an explosion of hydrofluoric acid. The internet seems to suggest lime (->fluorspar) or soda lye (->NaF, used for fluoridating water) to neutralize…
I suggested fluorspar rather than NaF because a backyard full of fluorspar is a pretty rock garden, while a backyard full of NaF is a toxic waste dump.
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Cl ions are fine; dissolved table salt consists of them, plus some cations. The copper is more of a problem, and I don't know the official answer. I'd think that if you could oxidize it to copper monosulfide (covellite), cupric oxide (tenorite), or even fully hydrated copper carbonate (malachite) if you don't have acid rain, that would adequately protect it from weathering and thus allow you to dispose of it safely.…
First warning with neutralizing acids: You're going to release a lot of heat, make sure you have a large thermal mass to absorb it. Someone else mentioned mixing your ingredients with water first. This is why. From what I understand the last thing you want to experience is an explosion of hydrofluoric acid. The internet seems to suggest lime (->fluorspar) or soda lye (->NaF, used for fluoridating water) to neutralize…
Don't mix this stuff in dilution in an enclosed space either as the H2 gas can create another explosion hazard.
I love this! Nanofabrication was one of my favorite classes and even with fancy equipment and worked out ahead of time instructions making a transistor took a huge amount of time and a good number of missteps. Can't imagine the amount of work required to do it all from scratch. Though I also think the safety lectures scared me sufficiently that I wouldn't want to touch HF acid ever again.
What class is this?
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What class is this?
The course number was ES277, though the professor left and it doesn't look like it's currently being offered under that course number. Not sure if there's a replacement class or the department decided to quietly shut it down. Wouldn't be surprised if it was the latter. The class was rumored to be the second most expensive one offered by the university, after the one where you got to grow organs in a petri dish. I als…