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| Chip making process |
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| coppice:
--- Quote from: jmelson on October 16, 2018, 06:32:10 pm --- --- Quote from: ZeroResistance on October 16, 2018, 06:17:46 pm ---Ok so that makes it 1000 * $1600 per wafer or USD 1.6M per month. But you also do get 15000 dies per wafer or 15000 * 1000 = 15M dies per month. So per die cost is 15000/1600 that is around $0.11. Seems to be pretty good for a 10F. But Microchip need to have assured sales right for it to be profitable? Another issue for Microchip 15M chips per month is a lot, how will they sell that much, they may probably have another deal with the foundry? --- End quote --- But, DO NOT FORGET, your mask set costs you about $1 million - maybe even a lot more! --- End quote --- His figures are for a 350nm process. Masks for 350nm processes are not $1M. |
| coppice:
--- Quote from: jmelson on October 16, 2018, 06:34:51 pm --- --- Quote from: coppice on October 16, 2018, 06:29:32 pm ---They regularly run a single wafer from a mask set, but you might have a point. I don't actually know anyone who went to a foundry and only did one wafer of business with them. --- End quote --- I believe MOSIS typically runs about 3-5 wafers for their multi-project runs. That is a bit of insurance against goofs at the foundry. The cost of the extra wafers TOTALLY disappears compared to the cost of the masks. --- End quote --- Sure, it makes no rational sense to process just one wafer after spending a fortune to make a mask set. Back in the 80s, in the 2um era, direct e-beam written wafers were much saner as one offs. |
| Wimberleytech:
--- Quote from: coppice on October 16, 2018, 06:29:32 pm --- --- Quote from: Wimberleytech on October 16, 2018, 06:25:28 pm --- --- Quote from: coppice on October 16, 2018, 06:14:11 pm --- --- Quote from: Wimberleytech on October 16, 2018, 06:08:33 pm --- --- Quote from: ZeroResistance on October 16, 2018, 06:01:12 pm --- --- Quote from: Wimberleytech on October 16, 2018, 05:48:35 pm --- To work with a foundry, you will have to commit to many thousands of wafers in production. --- End quote --- So did you have to commit for like 5000 wafers? --- End quote --- That is a detail I do not recall. I would think at least 1000 wafers/month. A foundry is in the speculation business. They will make a bet on your viability. If they believe in your business plan, they will be willing to do much smaller quantities while betting on the future large volumes. --- End quote --- A foundry will happily process a single wafer for you. The price won't be the same as when you run a thousand wafers a month, though. --- End quote --- Have you ever had a foundry run a single wafer for you? --- End quote --- They regularly run a single wafer from a mask set, but you might have a point. I don't actually know anyone who went to a foundry and only did one wafer of business with them. --- End quote --- A foundry (e.g., TSMC) will run a prototype lot (generally six wafers) with the expectation that it will turn into production after validation. They have billions invested in the foundry. They cannot run a single wafer here and there for somebody doing a science project. |
| Wimberleytech:
--- Quote from: coppice on October 16, 2018, 06:35:52 pm --- --- Quote from: jmelson on October 16, 2018, 06:32:10 pm --- --- Quote from: ZeroResistance on October 16, 2018, 06:17:46 pm ---Ok so that makes it 1000 * $1600 per wafer or USD 1.6M per month. But you also do get 15000 dies per wafer or 15000 * 1000 = 15M dies per month. So per die cost is 15000/1600 that is around $0.11. Seems to be pretty good for a 10F. But Microchip need to have assured sales right for it to be profitable? Another issue for Microchip 15M chips per month is a lot, how will they sell that much, they may probably have another deal with the foundry? --- End quote --- But, DO NOT FORGET, your mask set costs you about $1 million - maybe even a lot more! --- End quote --- His figures are for a 350nm process. Masks for 350nm processes are not $1M. --- End quote --- Correct. I think a mask set was on the order of $50K. For a anything under 60nm, $1M may be close. |
| brucehoult:
--- Quote from: jmelson on October 16, 2018, 06:34:51 pm --- --- Quote from: coppice on October 16, 2018, 06:29:32 pm ---They regularly run a single wafer from a mask set, but you might have a point. I don't actually know anyone who went to a foundry and only did one wafer of business with them. --- End quote --- I believe MOSIS typically runs about 3-5 wafers for their multi-project runs. That is a bit of insurance against goofs at the foundry. The cost of the extra wafers TOTALLY disappears compared to the cost of the masks. --- End quote --- I've heard that there's no choice on multi-project runs as they are different size and shapes packed in and sawing up the wafer to extract some of the dice destroys other nearby ones. It's cheaper to pack them in and make multiple wafers than to align everything in rows and columns the size of the largest die in each row/column plus margin for the saw. |
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