[simoncion]

I know that the substrate isn't the expensive part. Even a cursory gut-check reveals a claim to the contrary to be bunk.

I felt that a somewhat detailed analysis of the inappropriateness of the analogy was better than a "Nuh uh! You're wrong!" response.

[Dylan16807]

Well the thing is you're analyzing in a way that's both in-depth and shallow at the same time. It doesn't matter that they have 'excellent structure' unless you care about actual wafer costs. Just use diamond prices and dimensions.

[simoncion]

> ...you're analyzing in a way that's both in-depth and shallow at the same time.

I can't really dispute that. I'm no expert in the field.

> Just use diamond prices and dimensions.

Isn't that more or less what I did?

Diamond price per gram depends on the quality of the diamond. If we're gonna address an opinion that includes statements like "Think of the cost of a modern high-performance IC as if it was made of diamonds, because diamonds and silicon are both crystalline structures, and silicon is chemically much like carbon, therefore the substrate manufacturing costs are bound to be very similar." [0], then it seems that we need to look at the cost of high-quality diamonds that are used for their crystalline properties, rather than just for their hardness.

I'm not at all sure, but I would suppose that it would be far more expensive to make one high-quality diamond sheet the size of a silicon wafer than it would be to make a bunch of high-quality diamonds each the size of a CPU die, or maybe cut down a larger one. If it is, then an analysis based just on like-sized crystals would be dramatically unfair. Perhaps you know far more about this than I do? Industrial crystal production is not exactly in my wheelhouse. :)

[0] Direct quote: "Did you know that a silicon wafer is a perfect crystal, structured like a diamond? Silicon is right underneath Carbon in the periodic table, which means it shares the same outer electron shell configuration. Making that ain't cheap." via [1]

[1] https://news.ycombinator.com/item?id=10056870

[Dylan16807]

What I'm saying is: it might be appropriate to look at specific kinds of diamond because of the complexity of lithography and such. But the purity of the wafer doesn't matter because that has nothing to do with chip cost.

That post was wrong about that being a driver of costs, and it's not fruitful to build on that wrongness.

An analogy that leads you to the right conclusion for the wrong reason is a toxic thing.

[simoncion]

Do you mean to say that silicon wafers with higher guaranteed purity are not more expensive than those with lower guaranteed purity? I'm seriously asking; I don't know.

To speak to the rest of your comment:

mozumder made an incorrect argument and backed it up with a dangerously misleading analogy. I attacked the analogy by demonstrating its inappropriateness.

In my most recent post, I have attacked his argument with an analysis of what appear to be the actual costs of the thing he's talking about.

[mozumder]

A wafer cost isn't insignificant. It's still a lot more expensive than aluminum platters in a hard drive, especially when you're dealing with gobs of chips in an SSD.

Add in processing costs and it really becomes a mess.

So, yes, wafer costs matter when you have to produce tons of silicon for an SSD.

[simoncion]

> A wafer cost isn't insignificant.

This [0] seems to indicate that in mid 2009, one could get a 300mm silicon wafer for -worst case- ~$120.

Likely usable wafer area: 90,000mm^2

Largest Intel i3 processor (Haswell) die area: 181mm^2

Max dies per wafer: 497

Silicon wafer cost per die:

* Assuming 0% defect rate: $0.24

* Assuming 50% defect rate: $0.48

* Assuming 99% defect rate: $30.00

Cheapest (Celeron) Haswell on sale at Newegg today: $44.99. Average i3 Haswell price: $140. [1]

Unless Reuters is misinformed, or wafer costs have exploded in the past six years[2], the cost of the wafer truly does appear to be insignificant, even if we assume that wholesale prices are 50% of retail prices.

[0] http://www.reuters.com/article/2009/07/21/shinetsu-idUSBNG50...

[1] https://pcpartpicker.com/trends/price/cpu/

[2] This seems unlikely, as memory and chip costs haven't exploded in the past six years.

[mozumder]

This thread is about SSDs. You're forgetting that you need a hundred of these to make a 1TB SSD.

Consider the $0.24/die, and multiply that by 100 to get a 1 TB SSD drive.

Your SSD now has a minimum cost of $24, just for the silicon. That's extremely expensive. You can never sell your SSD for cheaper than that, just to cover the silicon costs of a 1TB drive, never-mind processing, manufacturing, distribution, sales, and profit. And you're competing against 5TB hard drives that sells for $100. (the 16TB SSD meanwhile apparently uses 500 chips..)

This is why wafer costs are like diamonds, instead of aluminum platters.