4 ms·

I’ve often wondered about die thinning. I mean just looking at sd cards and micro sd etc, it was clear that there had to be a thinning step (or many steps) and

by y1n0 12d ago

I’ve often wondered about die thinning. I mean just looking at sd cards and micro sd etc, it was clear that there had to be a thinning step (or many steps) and it seemed amazing to me that such a complex step could be economically viable. And yet it clearly is. All a matter of being able to operate at scale I guess. It’s not a step I’ve seen discussed very much, so it was kind of neat to see it discussed front and center in a lay article like this.

KurSix 12d ago
Yeah, the scale is kind of mind-bending. You're taking something that's already extremely fragile, grinding most of its thickness away, handling it through several more process steps, and somehow doing that cheaply enough for mass-market products.
- lazide 12d ago
  Automation, automation, automation. Zero chance you could do it if a human had to touch the die/chip directly during those steps. But clean room + vacuum pick and place machine? A matter of fine tuning, and it should work just fine.
- xadhominemx 12d ago
  The critical back end step for HBM is thermal compression bonding - where they actually compress 13 very thin die separated by solder balls. Cracking is a major issue.
  - pixl97 11d ago
    We are getting so many technologies like this that are so insanely specialized and require such deep knowledge of physical processes that some event like a 1918 flu that kills 10% of the population could take out enough people that we'd be unable to make things like this for years as we fill in the missing knowledge workers. It's just crazy how far down the scale we're tickling atoms these days.
    - benj111 11d ago
      Surely we'd have had the same issue during the Spanish flu? Any examples?
pjc50 12d ago
Planarization has always been part of the process: https://jeez-semicon.com/blog/Planarization-in-Semiconductor-Manufacturing-Complete-Guide/ https://jeez-semicon.com/blog/Planarization-in-Semiconductor... https://resources.pcb.cadence.com/blog/2023-the-planarization-process-for-semiconductor-manufacturing https://resources.pcb.cadence.com/blog/2023-the-planarizatio... Not dissimilar to lens or mirror making, the process of grinding to a precise flatness. The key step here is bonding it to a glass carrier, presumably because otherwise it gets too thin to support itself. See also the "reduced kerf diamond wire saw": technology critical to cheap solar panels is the ability to saw the boule into thinner and thinner pieces with less waste at each cut, like a big ham slicer.

by y1n0 12d ago

KurSix 12d ago

Yeah, the scale is kind of mind-bending. You're taking something that's already extremely fragile, grinding most of its thickness away, handling it through several more process steps, and somehow doing that cheaply enough for mass-market products.

lazide 12d ago
Automation, automation, automation. Zero chance you could do it if a human had to touch the die/chip directly during those steps. But clean room + vacuum pick and place machine? A matter of fine tuning, and it should work just fine.
xadhominemx 12d ago
The critical back end step for HBM is thermal compression bonding - where they actually compress 13 very thin die separated by solder balls. Cracking is a major issue.
- pixl97 11d ago
  We are getting so many technologies like this that are so insanely specialized and require such deep knowledge of physical processes that some event like a 1918 flu that kills 10% of the population could take out enough people that we'd be unable to make things like this for years as we fill in the missing knowledge workers. It's just crazy how far down the scale we're tickling atoms these days.
  - benj111 11d ago
    Surely we'd have had the same issue during the Spanish flu? Any examples?

pjc50 12d ago

Planarization has always been part of the process: https://jeez-semicon.com/blog/Planarization-in-Semiconductor-Manufacturing-Complete-Guide/ https://jeez-semicon.com/blog/Planarization-in-Semiconductor... https://resources.pcb.cadence.com/blog/2023-the-planarization-process-for-semiconductor-manufacturing https://resources.pcb.cadence.com/blog/2023-the-planarizatio... Not dissimilar to lens or mirror making, the process of grinding to a precise flatness. The key step here is bonding it to a glass carrier, presumably because otherwise it gets too thin to support itself. See also the "reduced kerf diamond wire saw": technology critical to cheap solar panels is the ability to saw the boule into thinner and thinner pieces with less waste at each cut, like a big ham slicer.