3 ms·

I assume purity matters. It probably picks up a lot of contaminants during use, and chip manufacturing is pretty sensitive to contaminants.

DoctorOetker 7mo ago
you can put He in a closed loop system and still use it for cooling, by using it as the thermodynamic working fluid, and then selecting any other fluid as the heat carrier?
- naasking 7mo ago
  That's not clear actually. It's been awhile since I watched the video on the ASML EUV system for etching wafers, but from my recollection, the UV light ablates away layers of wafers and so particles of silicon presumably contaminate the noble gas that's flowing over it. I don't think a closed loop is possible in the existing setups.
  - DoctorOetker 7mo ago
    thats what I am questioning, wouldn't another gas be feasible? I do know that some parts and components actually do have helium enclosed in the part package (can or so, not the shipping packaging!) I'm getting mixed signals: its for the phase transition temperature, its for cleaning, ... is EUV actually ablating layers of wafer? I thought the EUV was for patterning photoresist, you make it sound like ASML eliminated photoresist?
    - naasking 7mo ago
      Here is the Veritasium video where they review ASML's EUV lithography in depth: https://www.youtube.com/watch?v=MiUHjLxm3V0 https://www.youtube.com/watch?v=MiUHjLxm3V0 High thermal conductivity, inertness, and low absorption of the EUV wavelength used are the primary characteristics needed, and purity is needed to eliminate contamination of numerous ultrasensitive stages. AI summarized it as follows: EUV tools require ultra‑high‑purity helium, typically grade 9N (99.9999999%) or better, with strict ppb‑level limits on: Nitrogen, Oxygen, Moisture, Hydrocarbons, Refractory compounds, Particulates. How helium is used: - Cooling the EUV plasma source - Purging and protecting optics - Maintaining inert, ultra‑clean environments - Leak detection

DoctorOetker 7mo ago

you can put He in a closed loop system and still use it for cooling, by using it as the thermodynamic working fluid, and then selecting any other fluid as the heat carrier?

naasking 7mo ago
That's not clear actually. It's been awhile since I watched the video on the ASML EUV system for etching wafers, but from my recollection, the UV light ablates away layers of wafers and so particles of silicon presumably contaminate the noble gas that's flowing over it. I don't think a closed loop is possible in the existing setups.
- DoctorOetker 7mo ago
  thats what I am questioning, wouldn't another gas be feasible? I do know that some parts and components actually do have helium enclosed in the part package (can or so, not the shipping packaging!) I'm getting mixed signals: its for the phase transition temperature, its for cleaning, ... is EUV actually ablating layers of wafer? I thought the EUV was for patterning photoresist, you make it sound like ASML eliminated photoresist?
  - naasking 7mo ago
    Here is the Veritasium video where they review ASML's EUV lithography in depth: https://www.youtube.com/watch?v=MiUHjLxm3V0 https://www.youtube.com/watch?v=MiUHjLxm3V0 High thermal conductivity, inertness, and low absorption of the EUV wavelength used are the primary characteristics needed, and purity is needed to eliminate contamination of numerous ultrasensitive stages. AI summarized it as follows: EUV tools require ultra‑high‑purity helium, typically grade 9N (99.9999999%) or better, with strict ppb‑level limits on: Nitrogen, Oxygen, Moisture, Hydrocarbons, Refractory compounds, Particulates. How helium is used: - Cooling the EUV plasma source - Purging and protecting optics - Maintaining inert, ultra‑clean environments - Leak detection