3 ms·

> HP achieved a yield of 9%, meaning 91% of the dies failed. This line really stood out to me - I was aware early semi yields were poor, but this poor? Was thi

> HP achieved a yield of 9%, meaning 91% of the dies failed. This line really stood out to me - I was aware early semi yields were poor, but this poor? Was this par-for-the-course for technology at that time, or was this bad even by 70s standards? What do typical yield numbers look like today?

deleted 3y ago
[deleted]
gary_0 3y ago
I recall reading that a brand new cutting-edge process node might get 60% yield, but a completely mature node is circa 90% (if memory serves). Yields for a new process usually go up over time as manufacturing bugs are worked out.
- Baldbvrhunter 3y ago
  Isn't that survivorship bias? Processes that never improve yield are abandoned
  - kragen 3y ago
    no, it's just what happens with any process; as you gain more experience with it, you learn more about it, so you can get more and more controlled results
    - gary_0 3y ago
      Yes, and companies like TSMC and Intel probably have vast internal documentation about where and how their processes can improve yield as they run their newest fabs. The research required to implement a new process can take decades to get to the mass-production stage. Given the billion of dollars at stake and thousands of human-years of R&D needed, none of these companies are "winging it" and their scientists and engineers know how to plan ahead to the best of their considerable abilities. For a glimpse at how they do things, see this fascinating talk: https://www.youtube.com/watch?v=NGFhc8R_uO4 https://www.youtube.com/watch?v=NGFhc8R_uO4
      - shard 3y ago
        > Given the billion of dollars at stake and thousands of human-years of R&D needed, none of these companies are "winging it" You'd be surprised. My personal knowledge of one major fab is that they have policies such as regular rotation of employees which make it difficult to maintain institutional knowledge. I have heard complaints from multiple people of their teammates and managers "winging it" to think it's isolated incidents.
        gary_0 3y ago
        Cynical thoughts along these lines occurred to me after I posted my comment, so no, I'm not surprised, just disappointed. Especially not after watching Intel slowly rot from the inside (good luck with your renovations, Mr. Gelsinger). My workmate at my last job (pre-COVID) knew someone who worked at Intel, and our discussions about the company tended to contain the phrase "Intel is fucked" an awful lot. This was around the time I bought a nice chunk of TSMC stock...
  - gary_0 3y ago
    Historically, maybe, but otherwise that's not how it works. Nowadays, when a new process enters risk production, yields are expected to be sub-optimal (I think I read that some of the recent stuff TSMC was making for Apple was below 50%) but it's an economic imperative that they improve (and they do). Abandoning a process once you've built an assembly line would be an existential crisis for a high-end semiconductor company, given the billions of dollars it costs to get to that point (which is a big reason why Intel has been between a rock and a hard place for the past 5 years or so).
raverbashing 3y ago
I wonder if the hard part is interfacing the sapphire with the silicon, heterogeneous materials like that are always an issue
- bsder 3y ago
  In 1977, everything was hard. Growing just silicon crystals was still difficult let alone on sapphire--3 ionch wafers were the norm. Lithography was contact so degrade your masks over time. Threshold voltages had poor control. CMOS chips were very susceptible to ESD punchthrough. Latchup was murderous (SOS helps cut this down greatly). You had purple plague. I can go on and on.
  - kragen 3y ago
    interestingly, the day after you posted this, popular youtuber nilered published a video in which, after staggering amounts of effort, he successfully makes a beautiful finger ring for himself from purple plague https://www.youtube.com/watch?v=d6Pcp944sRI https://www.youtube.com/watch?v=d6Pcp944sRI

deleted 3y ago

[deleted]

gary_0 3y ago

I recall reading that a brand new cutting-edge process node might get 60% yield, but a completely mature node is circa 90% (if memory serves). Yields for a new process usually go up over time as manufacturing bugs are worked out.

Baldbvrhunter 3y ago
Isn't that survivorship bias? Processes that never improve yield are abandoned
- kragen 3y ago
  no, it's just what happens with any process; as you gain more experience with it, you learn more about it, so you can get more and more controlled results
  - gary_0 3y ago
    Yes, and companies like TSMC and Intel probably have vast internal documentation about where and how their processes can improve yield as they run their newest fabs. The research required to implement a new process can take decades to get to the mass-production stage. Given the billion of dollars at stake and thousands of human-years of R&D needed, none of these companies are "winging it" and their scientists and engineers know how to plan ahead to the best of their considerable abilities. For a glimpse at how they do things, see this fascinating talk: https://www.youtube.com/watch?v=NGFhc8R_uO4 https://www.youtube.com/watch?v=NGFhc8R_uO4
    - shard 3y ago
      > Given the billion of dollars at stake and thousands of human-years of R&D needed, none of these companies are "winging it" You'd be surprised. My personal knowledge of one major fab is that they have policies such as regular rotation of employees which make it difficult to maintain institutional knowledge. I have heard complaints from multiple people of their teammates and managers "winging it" to think it's isolated incidents.
      - gary_0 3y ago
        Cynical thoughts along these lines occurred to me after I posted my comment, so no, I'm not surprised, just disappointed. Especially not after watching Intel slowly rot from the inside (good luck with your renovations, Mr. Gelsinger). My workmate at my last job (pre-COVID) knew someone who worked at Intel, and our discussions about the company tended to contain the phrase "Intel is fucked" an awful lot. This was around the time I bought a nice chunk of TSMC stock...
- gary_0 3y ago
  Historically, maybe, but otherwise that's not how it works. Nowadays, when a new process enters risk production, yields are expected to be sub-optimal (I think I read that some of the recent stuff TSMC was making for Apple was below 50%) but it's an economic imperative that they improve (and they do). Abandoning a process once you've built an assembly line would be an existential crisis for a high-end semiconductor company, given the billions of dollars it costs to get to that point (which is a big reason why Intel has been between a rock and a hard place for the past 5 years or so).

raverbashing 3y ago

I wonder if the hard part is interfacing the sapphire with the silicon, heterogeneous materials like that are always an issue

bsder 3y ago
In 1977, everything was hard. Growing just silicon crystals was still difficult let alone on sapphire--3 ionch wafers were the norm. Lithography was contact so degrade your masks over time. Threshold voltages had poor control. CMOS chips were very susceptible to ESD punchthrough. Latchup was murderous (SOS helps cut this down greatly). You had purple plague. I can go on and on.
- kragen 3y ago
  interestingly, the day after you posted this, popular youtuber nilered published a video in which, after staggering amounts of effort, he successfully makes a beautiful finger ring for himself from purple plague https://www.youtube.com/watch?v=d6Pcp944sRI https://www.youtube.com/watch?v=d6Pcp944sRI