The Costs of Making a DRAM Chip

Anonymous Coward writes "Researchers at the United Nations University in Tokyo studied the physical and environmental costs to produce one 32-megabyte DRAM chip. Their conclusion? The UNU team found that to make every one of the millions manufactured each year requires 32 kg of water, 1.6 kg of fossil fuels, 700 grams of elemental gases (mainly nitrogen), and 72 grams of chemicals (hundreds are used, including lethal arsine gas and corrosive hydrogen fluoride)."

Comments

Full text: The 1.7 kilogram microchip

[dietlein]

The publication itself:
Here.

"Used to make..."

[NitroWolf]

Those numbers may be "used to make" a single microchip, but it doesn't say those numbers are what is CONSUMED. That's what's important... how much of that material is consumed in making a single chip.

I suspect that 32kg of water is reused for many, many chips. Same with the other material. Obviously, you'll have SOME material consumed when making a single chip, but I find it difficult to believe all that is CONSUMED when creating a single chip.

More info needs to be presented about the consumption of materials to make a chip that what is "used" to make a chip.

Re:"Used to make..."

[ivan256]

Actually, reusing this water is one of the priorities of a few notable chip manufacturers right now. Not only are we learning how to reduse the amount of water used, but we're cleaning as much of it as we can afterward.

If you ask me, I think the biggest news in this article is that people aren't aware of what goes into making products that they take for granted. It's not like it takes alot of effort to realize that alot of energy and chemicals are required to make microchips. It's just that only a small minority of us actually pay attention.

It's probably mixed with chemicals and sprayed on at some point and then dribbles through catchbasins.

Actually the majority of it is probably used for cooling.

Re:"Used to make..."

[the_pooh_experience]

certainly some of tme can be reused (H20 as you and others correctly stated for example). But here are typical applications of different chemicals:

• H20: the vast majority of this is used in cleaning baths. It is always deionized water and ususally is operated in a "flow-through" manner such that there is a big tank where they put wafers and water flows into and out of this tank. 32 Kg of water likely accounts for the fact that these baths are probably kept on (because water is cheap) while wafers are not in there. The other use for this is to create steam, which when exposed to Silicon, creates silicon-dioxide (SiO2) which is typically used as an insulator.
• N2: Okay, this is probably not reused primarily because of the manner it is used. Typically the N2 is used like a hose to dry off wafers (like a gun). This N2 typically is simply added to the 80-some percent of N2 in the ambient air. N2 is used in lesser quantities for replacing bad gasses in vacuum chambers (known as "flushing"), but the fact that this "pure" N2 is mixed with other "bad" gasses, it is probably difficult to use without large amounts of purification. Finally, production facilities probably use this in their storage area (wafer storage) as to avoid unwanted oxides growing on the surface (see below).
• As: this is really bad (as most of you kiddies know) and is used in doping the Si to make it more conductive, etc (along with other chemicals). This is one of the gasses that N2 is used to flush out of the vacuum system.
• HF: This is (afaik) the primary technique (as outlined in the RCA cleaning process to remove native oxides on the surface of the Si. As stated above, when Si comes in contact with water vapor (rich in oxygen), it forms SiO2. Well when Si comes in contact with O2 in ambient air (at a lower concentration), it will also create thinner films of SiO2, and this needs to be removed with something, which HF works very well for. This is typically neutralized and disposed of.

I am inclined to believe that most of the chemicals are not reused, at least in the traditional sense. H2O is cleaned and returned to the ocean, and N2 is cleaned (through air-handling systems) and returned to the atmosphere, but many of these chemicals probably are neutralized (read "made somewhat safe") and disposed of in your local land-fill, or into your local air.

Re:eep..

[scotch]

Ok, kids, go ahead and eat those old simms and dimms.

Re:Recycling

[eglamkowski]

The problem is... At one point I was trying to recycle a bunch of old hardware and did some research. I recall reading at one point (I forget exactly where, unfortunately) that many of the companies that recycle old hardware don't.

What they do do is put it on a slow boat to China where it is dumped into the rivers. Rivers that locals rely upon for drinking water. And then, to supplement their income, some of the chinese people will take the hardware and pick out the copper and other metals to sell. But they don't wear any appropriate protective gear, not even gloves.

So, basically, "recycling" is just a long process by which we make it someone else's environmental problem :-/

Not all recycling companies do this, but many do. If you want to go this route, be sure you research the companies thoroughly. I ended up not recycling (yet), but found some buyers who had a use for the old hardware.

How bad is it really?

[stratjakt]

this sounds like a 'worst case scenario' type of analysis.

I'm not denying that the chip industry isnt doing Mother Nature any favors, but what exactly do these numbers mean?

I mean, I hear from environmentalist types that every glass of water you drink takes 2 glasses to wash and another 2 to rinse it. But, the water doesnt dissappear or become unusable. It makes its way back into the system.

So of 32 kg of water 'used', how much of that becomes contaminated to the point that it cant be re-used? If its a coolant that evaporates as steam, then I don't see the big deal. If its turned into toxic sludge with a half life measured in eons, then it probalby is.

And WRT to fossil fuels, are they directly used in manufacturing, or are we talking how much needs to be burned to create the electricity needed to manufacture? And why talk about fossil fuels, and not Uranium or solar/hydro/wind power? Because it gets more attention? Wouldnt kW/h would be a better measure? What matters is how much energy is expended.

I understand that we need to better watch and control our impact on the environment, but infactual data and meaningless statements like 'it takes 300 bananas to make a wingnut' don't help.

I worked at Samsung - Believe the numbers

[redbeard_ak]

In 97' I worked at Samsung's fab in Austin, Texas as a chemical technician, troubleshooting and maintaining the pumps that sent liquid chemicals up to the fab. I also pushed a lot of drums and hooked up tanker trucks of sulfuric and other nasties to the hungry fab.

As the average slashdotter knows, every chip is composed of multiple layers, each masked and etched, bathed in various acids and bases and then neutralized and cleaned before the next layer can be applied.

Then these waste chemicals are pumped out, neutralized (in theory) and diluted before being dumped into the same waste water stream that eventually hits streams, rivers and ground water.

There's a whole lot of water indirectly consumed in the manufacturing process - but a whole order of magnitude more water consumed and dumped to dilute the hopefully neutralized (ie, salts) waste products.

So I believe the numbers - kgs (ie, liters!) of water per MB does not set off my bullsht detector.

To me, it also brings into question the whole drive of chip research. It's all focused on performance. There are some articles on research into environmentally friendy chips. But when did you hear of a chip marketed as enviro-friendly? We're tempted into buying the another chip just a tick faster but not even given the choice. For consumers to even be able to make the choice for a more sustainable product we have to have the information.

But companies don't even want us to know what we're injesting - that isn't important to them and is contrary to their creation of demand for more stuff. Why would we think they would tell us something against their own short-term interest?

Re:Recycling

[metlin]

Not to flame, but I felt the following points relevant.

You do realise that you are talking from the perspective of someone from a developed country, where any school can afford to use a PIII/500?

You do realise that there are countries where all that a public school would have is probably ONE computer which all the students get to SEE and not work on?

A school isn't going to teach word processing on anything less than a 500 Mh PIII.

I think Office 97 did indeed run very happily on an 133 Mhz system? My dear friend, applied computer use does not necessiate the use of the latest bleeding edge graphical OS with the latest bloated word-processing app.


A school teaches applied computer use, not CS, so an account isn't much help.


Don't be too sure. Hell, I learnt Basic and Dbase in my 4th and 5th grade in school. That would again depend on your school.

let alone figure out how to install Linux on an old PC.


Here in India, the use of Linux is being spread in several small schools without enough funds.

What are the benefits? You have 8th grade kids who are familiar with the command line and 10th and 12th grade kids who can whip up Perl scripts. They have an environment to explore. And they are learning a technology that is here to stay.


A school isn't going to use a linux firewall.


Duh! And why not?

Is it because its too complex? If it helps, my high-school project for my final CS paper was an Parallel Operating System.

Is it because its not widespread? If you are talking about a school without resources, hell they'll take just about anything you give them.

In MANY schools that I know of with a single dial-up connection being shared by many computers, guess what OS runs the machine connecting to the Internet?


This still doesn't address the long term problem. What do we do with the old PCs in 5 more years (when all the schools have old PCs)?


Well, don't you know? We would have a BEOWULF CLUSTER of those!!! ;-)