Ask HN: Environmental Cost of Semiconductors?

54 points | by drallison 193 days ago


  • beefman 193 days ago

    You are asking for an LCA of electronic components. The best ones are proprietary, such as the one we put together at Apple ten years ago, which is probably still updated and unrivaled.

    The good news is that electronic components often obey commodity pricing. And for commodities there is a very good approximation for LCA: their market price.

    An LCA is a sum environmental impacts, weighted by importance. Market price represents some sort of consensus weighting. You can argue for other weightings, but such arguments are at least as subjective as the market weights and seldom give a significantly different result.

    Interestingly, even non-commodities reveal their environmental impact through their price. The difference is, their prices include all downstream environmental impacts, whereas traditional LCA and commodity prices only reflect impacts within some "system boundary".

    • wiz21c 193 days ago

      >>> The best ones are proprietary,

      If you mean "secret", then we're not going to progress much. Impact on environment is not like impact on your finance. Your finance are private, the environment is everyone's. Therefore, everyone's must have access ton the information needed to assess if the impact is acceptable or not.

      • rcfox 193 days ago

        LCA = Life cycle... assessment?

        • beefman 193 days ago

          Usually (sometimes Analysis)

      • sevensor 193 days ago

        Toxic materials (photoresist and associated solvents, acids for cleans, dopant chemicals, among others) and lots of electricity get used in the semiconductor manufacturing process. And that's just at the wafer manufacturing site. It doesn't include materials for packaging or PCBs. Nor does it include the chemical plants that supply materials, or the environmental impact of producing the manufacturing equipment (which will only be used for a decade, 15 years at the outside), and its consumables. If you're concerned with the environmental footprint of your personal computing, you should probably use older equipment for longer. I think the balance is different for datacenters given their high utilization.

        • thrilleratplay 193 days ago

          This would be a fascinating read if one exists, however, if I had to guess with no actual basis for it, what you describe is too broad and would need to be broken down. A few simplifications:

          * The environmental impact of mining, refining and shipping of the ultra pure silicon needed for semiconductor development.

          * The energy required to research/development then produce next generation semiconducting and at what yield or adoption rate would it make sense to push Moore's Law.

          * Percentage of electronics that end up in landfill verse what is recycled.

          I am having trouble trying to think of other clear examples beyond the fab due to too many variables. How do distinguish processors and GPUs in someone's gaming rig using power from a local coal plant to a cloud farm that is using wind and solar to power it? To throw another wrench into this there is also you

          • mchannon 193 days ago

            Call it anecdata, but a few of the things I noticed after a couple decades in the industry:

            1. Water

            Water is extensively used and it has to be as pure as you can imagine. This requires a regular investment in filters and energy. I wouldn't be surprised to see hundreds of water wash steps for a wafer of chips, plus water wash steps for the equipment.

            2. Acids and bases

            You can dump these in the third world, sure, but neutralizing them tends to be favored, and also very expensive. Sulfuric or Hydrofluoric acid may require almost zero energy input, but the caustic soda, soda ash, or baking soda you need to add to passivate their waste requires a lot.

            3. Silicon itself

            This one's a bit of a surprise. A gram of hyperpure silicon doesn't really take that much energy, or even generate all that much waste. There's the reduction cost where you burn out the oxide with coal and wood chips, plus the follow-up stages of purification and crystallization. You lose half again by wafering. But even if it's 10 grams waste per gram of chip, you're not doing all that poorly. An idling car engine makes 10 grams of waste in no time. Plus the waste is almost entirely mg-Si, CO, and CO2; very manageable. China has a bit of a silicon-tetrachloride problem from some of its purification steps, but that stuff is avoidable.

            4. Photoresists

            These are the absolute worst. Carcinogenic and complicated to manufacture.

            5. Specialty gases

            What's a little diborane, phosphine, or arsine among friends? These players are bad news, but you use such trivially small quantities of them that their impact is pretty light. You still have to scrub their waste gases out before you release them, and that's a bit of a pain.

            6. Bulk gases

            Hyperpure nitrogen, oxygen, and argon get used in large amounts as well but they're almost as cheap as air in bulk. Release at will.

            7. Air handling

            Cleanrooms require more airflow than some bitcoin farms, and specialty filters have to be changed out occasionally. It's just electricity though.

            8. Packaging

            All that copper, tin, silver, and gold, plus whatever weird plastics they're using these days may end up being far worse for the environment than the chips they encase.

            9. Actual use

            Unless they're generating power (PV) they're going to suck down power, whether in your cable box set to off or the switchgear. This is by far the biggest energy consumption associated with semiconductors.

            10. Vacuum!

            Along with to a lesser extent compressed air, vacuum greases and machinery can get up there in terms of cost. Roughing pumps will spew oil, and turbo pump and cryopump units cost a lot to build, run, and maintain.

            11. Organic solvents

            Cheap to make, expensive to dispose, doubly so when you mix them with some of the other expensive-to-dispose stuff.

            • sevensor 193 days ago

              Great answer, and nice to see another person from semiconductor manufacturing on this site! Are you still in the industry?

              • mchannon 193 days ago

                Trying to be, but can't get people excited about making silicon wafers with higher purity, zero waste products and at 10% the cost.

                So in the meantime I write apps.

                • sevensor 193 days ago

                  > higher purity, zero waste products and at 10% the cost

                  That's disappointing! For an industry that's at the heart of so much modern technological advancement, it's surprisingly conservative. And that goes double for choosing suppliers, unfortunately. Myself, I got worn down by the hours and left the industry.

                  • matt_the_bass 191 days ago

                    Have you built a proof of concept or demonstration wafer?

                  • sigmaprimus 193 days ago

                    I agree, very well thought out and resonable response to a very difficult question!

                • ChuckMcM 193 days ago

                  An independent review? I haven't seen one. There was a pretty egregious report alleged to be from the Silicon Valley Toxics Coalition[1] which appears to have been taken down. (It was conflating ground water contamination from fabs in the 60's with modern fabs, for example)

                  If you were looking for a project it would probably be a good one, I for one would be interested in reading something that was backed up by solid research and objectivity.


                  • davidjnelson 193 days ago

                    A nice map view of how polluted Silicon Valley is

                    • vkaku 193 days ago

                      Follow the law. We need to have Federal laws that require Electronics Companies or Importers to recycle their equipment. Those Federal laws do not exist today.

                      In the USA, corporations fight right to repair laws. That's the current state of the affairs. It has to transition from that into a more thoughtful usage driven buying/selling process.

                      There is nothing wrong in buying newer, better electronics - but junking the old ones as e-waste is absolutely wrong.

                      • sigmaprimus 193 days ago

                        I'm not sure if there is or not, but I would hope that any review would also include the reduction of power consumption from using semiconductors instead other non solid state devices. Eg Vacuum tubes vs transistors. Also the increased efficiency of switching power supplies over linear.

                        • mistrial9 193 days ago

                          yes, there are .. contact BAN-Waste in Seattle to start if you are in a hurry, and given 48 hours or so, more doc references here in this thread TBD. A keyword search with "Industrial Ecology" from the early 2000s might get things rolling, too.