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.

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.

Re:Recycling

[simi-lost]

Maybe you should take a look at this site then. http://news.bbc.co.uk/1/hi/sci/tech/1839997.stm Computers sent to recyclers in America, and other countries for that matter are ending back in Asia. yes, some is recycled and that's good, but a lot of toxins are leached out... We should recycle ours here where we have regulations to control this, but then again, if we did recycle while being responsible, then it would cost more than it's worth..

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:"Used to make..."

[ivan256]

Chips with higher densities are more fragile, and therefore will give lower yields.

Tell that to Intel They seem to have increased the circuit density, wafer size, performance and yield, all while reducing consumption.

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?