Nikon's 'Hundred's' line to be discontinued?

[OreoCookie]

I am not saying that full frame sensors are going to become affordable any time soon, but where do you get your yield figures from?

I would suppose from the source he has quoted before, Canon's full frame white paper. (Don't hesitate to correct me if I'm wrong, though, compuwar).

 

[ksz]

Claiming that there's a possibility of a 90% yield in the current CMOS processes for 35mm sized imaging sensors is disingenuous.

Please be careful. I have been saying that the semiconductor industry has always innovated itself out of brick walls, and I have provided examples of such innovation. I have not said that current CMOS processes for full frame imaging sensors will get to 90% yield, but that process improvements take place continuously and there is significant incentive to do just that as the market for full frame sensors grows.

Like OreoCookie, you are also fixated on the notion that improvements in sensor yields will not occur for the foreseeable future, but you are not citing objective data. A 2006 white paper from Canon is not representative of sensor yields today.

Any process improvement also applies to smaller sensors, so you really have to get APS-C to near 100% then make more improvements, then go to square wafers before you get parity.

Fabrication of large image sensors presents some unique challenges that are not applicable to small sensors. Large reticles with edge defocus issues may be one of these unique problems. Your absolute statement that "any process improvement" also applies to smaller sensors is naive.

I don't know why you keep bringing up "square" wafers. That's not something that's going to happen any time soon. It should not be part of any realistic argument.

The semiconductor industry is currently researching a move to 400mm wafers (Intel made some noise about 450mm wafers a couple of years ago). The transition will not happen for at least another 5 years. Obviously this will increase the number of full frame sensors per wafer, but I won't argue this line because it is too far out.

The position advanced is that the _delta_ between APS-C and 35mm sized imaging sensor yields will remain relatively high for the foreseeable future. If we see a 30% improvement at the 35mm end, the APS-C end should gain enough that you're still talking a significant difference, perhaps even a larger delta

This again depends on the premise that any process improvement for full frame sensors also applies to smaller sensors, which again is a naive assumption.

Nobody in the fab industry seems to see anything groundbreaking coming.

Citations please.

Going to smaller process sizes for imaging sensors really doesn't affect yields like it does for other semiconductors because you can't remap a pixel somewhere else on the sensor and get the same results.

And no one is claiming that.

The smaller your photosites the quicker diffraction rears its ugly head, and the more photosites are likely to be affected by a single defect on the wafer. That's why image sensor defects that aren't manufacturing process issues (like damage while cutting the wafer) have kept yields relatively static between different sized sensors. If it were otherwise, you'd see Hasselblad taking on the full frame folks at the high end and kicking their butts- but they're penalized even more than the 35mm sensor folks from yields.

This is not relevant because no one is claiming that image sensors are subject to die shrink.

 

[eddx]

Im gunna say no, the D300 / D200 / D100 line is here to stay. I would expect to see a D400 in the next 18 months with a 21mp DX sensor. It is a prosumer DX sensor DSLR.

D80/D90 is the flagship DX sensor and D40x/D60 is the basic DX DSLR.

DX for amteurs and FX for pros is the way I see Nikon going. Otherwise why would they be bringing out more DX lens?

By the way, I am a pro who is happy with the quality I can get from the DX sensor and my work doesn't require or justify FX at this moment in time.

 

[Westside guy]

Im gunna say no, the D300 / D200 / D100 line is here to stay. I would expect to see a D400 in the next 18 months with a 21mp DX sensor. It is a prosumer DX sensor DSLR.

I agree that the D400 will come, but I will be very surprised if the pixel density is that high. With photosites that small, diffraction would set in at (I'm guessing) about f/8. That'd put a severe restriction on the types of shots you could take with the camera.

I suspect Thom Hogan is right - the DX line will top out at 14-16 megapixels.

 

[Driver]

Yeah, that may be right, but I doubt it. I think market forces will decide whether or not the move is to full frame, not economics of sensor manufacturing, which have been, are, and will be subject to change over time (with traditionally decreasing cost). Obviously, those economics will affect the market, but I think it's clear that the market interest these days is on full frame and I suspect the camera-buying public won't be denied. I would be surprised if, in 3-5 years, it would be possible to even buy a professional-level cropped sensor camera from either Canon or Nikon.

It's inevitable. They have to increase mega pixels (and sensitivity) just to get people to upgrade. It's an industry that counts on people upgrading every 3-4 years. And they'll have to offer significant new cameras to force consumers to plunk down the cash. A full frame chip gives them room to to drive these changes (more pixels, better sensitivity, etc..), regardless of the price, which naturally will come down with time and process improvements.

Even though I've only had my D300 for a month I guaranty I don't go looking for DX lenses for it. I'll buy a lens for a full frame camera and make do until I can upgrade to the D5 in several years. The proliferation of DX lenses will have that segment hang on a little longer than I think some anticipate but Nikon will cut them loose from their ProSumer/Professional segment without much fanfare. They'll keep a low end slr in their lineup for 10 years or so just for users of those lenses but the middle to high end SLRs will be Full Frame soon enough. My guess is more like 7-8 years as the photography chip market moves a lot slower than the computer chip market. If they were equal we'd all be shooting with 80MP cameras by now.

By the time I go to a full frame camera I expect the iPhone will have a 4-6MP sensor in it.

 

[compuwar]

Please be careful. I have been saying that the semiconductor industry has always innovated itself out of brick walls, and I have provided examples of such innovation. I have not said that current CMOS processes for full frame imaging sensors will get to 90% yield, but that process improvements take place continuously and there is significant incentive to do just that as the market for full frame sensors grows.

You said "Wafer yields are actually pretty high on long-life parts in 300mm fabs around the world, with greater than 90% sustained yield on even relatively large die sizes. Short-life parts where only a handful of lots are manufactured will most likely not see mature yields, but a part that exists for a long time ramps up to mature yield levels."

In a discussion about sensor yields- intimating (and certainly not disclaiming) that 35mm sensors (parts that exit for a long time- at least in terms of Canon's fab plant) on relatively large die sizes (and I'm assuming here that you consider a 35mm sensor to be a relatively large size) get greater than 90% yields. So either you're intimating that 35mm sensors should be getting 90% yields, or you're drawing a conclusion about the semiconductor industry that hasn't applied to imaging sensors so far and that none of the current imaging sensor manufacturers I've seen are trumpeting, telegraphing or making any noise at all about.

Like OreoCookie, you are also fixated on the notion that improvements in sensor yields will not occur for the foreseeable future, but you are not citing objective data. A 2006 white paper from Canon is not representative of sensor yields today.

Prove that it is not *representative*. I've looked at annual reports, patents, and everything else, and while nobody's pushing numbers like they were ~24 months ago, that's not a huge amount of time- and nobody's annual or even quarterly reports are talking about killer yield numbers. The relative numbers are the same, even if the absolute costs have gone down- and even if yields have gone up some, it's still a surface area problem.

Show me a more recent representative paper.

Finally, are you asserting that Canon replaces its steppers every 2 years for the same sensor line? While the numbers will have changed, their relative representations really don't seem to have changed- but I'd be happy to see some citations, because all the good analysis that I have is either 2 years out or difficult to sustain attempts to reverse the sensor price from the camera price and approximate profit margins.

Fabrication of large image sensors presents some unique challenges that are not applicable to small sensors. Large reticles with edge defocus issues may be one of these unique problems. Your absolute statement that "any process improvement" also applies to smaller sensors is naive.

Present a process improvement that will only benefit large sensors- the gain to smaller sensors may not be as material, but it will still apply- edge defocus issues have been solved, which is why it (reportedly) no longer takes more than one patterning step to produce a 35mm sensor- but multiple exposures didn't do anything to yield, it just spoke to process improvements- and it meant that you could expose more smaller sensors in a step- so it's not unique to larger sensors. It still doesn't address yields, but it's not a large sensor only improvement.

I don't know why you keep bringing up "square" wafers. That's not something that's going to happen any time soon. It should not be part of any realistic argument.

What part of "to achieve parity" don't you understand? Your mythical, but unknown "leap" isn't realistic as far as I can see.

The semiconductor industry is currently researching a move to 400mm wafers (Intel made some noise about 450mm wafers a couple of years ago). The transition will not happen for at least another 5 years. Obviously this will increase the number of full frame sensors per wafer, but I won't argue this line because it is too far out.

But again, it does nothing to address yields, so it's a strawman- more 35mm sensors means even more APS-C sensors, larger wafers isn't a sensor yield issue, it's a sensors-per-process-step issue.

This again depends on the premise that any process improvement for full frame sensors also applies to smaller sensors, which again is a naive assumption.

Unlike your assertion that alignment issues aren't a big deal, Canon's last annual report trumpets their new solution for alignment. They're also focused on inspecting for defects up front- which doesn't exactly scream "way cool improvements in yields by solving a problem with the wafer" now does it?

Once again, even if 35mm yields doubled, they'd still be 30% behind APS-C yields from two years ago. Nobody seems to be trumpeting a 100% increaase in 35mm sensor yields in the last two years, and since only Canon and the MF manufacturers were doing 35mm processes in volume it's not like there was a huge universe of folks attacking the problem. Feel free to show some real data and anything other than blind hope that the "industry" is going to "make a leap" that has no current substance.

 

[compuwar]

If they were equal we'd all be shooting with 80MP cameras by now.

It's not just how fast the industry moves, it's the difference that progress gets you. An 80MP 35mm sensor starts to show loss of sharpness due to diffraction at f/5.3. Not very useful in general photography.

 

[ksz]

In a discussion about sensor yields- intimating (and certainly not disclaiming) that 35mm sensors (parts that exit for a long time- at least in terms of Canon's fab plant) on relatively large die sizes (and I'm assuming here that you consider a 35mm sensor to be a relatively large size) get greater than 90% yields. So either you're intimating that 35mm sensors should be getting 90% yields, or you're drawing a conclusion about the semiconductor industry that hasn't applied to imaging sensors so far and that none of the current imaging sensor manufacturers I've seen are trumpeting, telegraphing or making any noise at all about.

You keep missing the point. The argument that yield is related to die size is true, but die size is not the only factor, nor the most significant factor. The TI digital micro-mirror device (DMD) has a relatively large die size, but the most complex part of the process is fabrication of the tiny micro mirrors that actually twist. Most of the yield loss comes from this part of the process. Drawing a blind argument between die size and yield is naive. Like an image sensor, a DMD chip does not have redundancy which could be used to reroute electrical signals from faulty circuits to redundant or backup circuits. But TI has developed other techniques to recover yield. There are "correctable" faults even on a DMD.

My statement about 90% yield on long-life parts is exactly meant to assert that achieving high levels of yield on FX sensors should not be considered impossible. People who believe in the impossible are, in my view, useless people. They are the ones who thought a mission to the moon was impossible, and they would never have undertaken the challenges needed to make it a reality. The semiconductor industry has solved numerous very challenging problems, and is about to solve the challenges for 22nm. To think that they cannot bring FX sensor yields above 20% is lunacy.

Prove that it is not *representative*.

You don't understand the rules pertaining to burden of proof. It is incumbent upon you to prove your assertion.

I've looked at annual reports, patents, and everything else, and while nobody's pushing numbers like they were ~24 months ago, that's not a huge amount of time- and nobody's annual or even quarterly reports are talking about killer yield numbers. The relative numbers are the same, even if the absolute costs have gone down- and even if yields have gone up some, it's still a surface area problem.

Do you know why you cannot readily find yield numbers? Fab yield is one of the most closely guarded secrets.

The market for FX sensors is currently very small, which does not provide incentive for companies to pour resources into developing new process technologies. For general semiconductor devices, development of new process technologies is very expensive, and getting more so. Consortiums such as Sematech and IMEC are formed to spread the costs. Once the market for FX sensors grows, I see every reason for R&D expenses to rise to meet the demand for volume and price.

Finally, are you asserting that Canon replaces its steppers every 2 years for the same sensor line?

No.

Present a process improvement that will only benefit large sensors- the gain to smaller sensors may not be as material, but it will still apply

Explain clearly why the larger die size of a Full Frame sensor is so difficult to manufacture. What are the specific fabrication problems? Now explain why these fabrication problems don't affect smaller die sizes, but only affect large die sizes. Now if we find a solution for the large die size problem, it will have the greatest benefit for large die and maybe nothing for small die.

Now let's say we have 100% yield on small sensors because we've made them really small. And we have 20% yield on large sensors because, well, because they're large. Now if I increase my yield on large sensors from 20% to 50%, will I increase my yield on small sensors from 100% to 120%? I would really like to see that!

The point is clear: you have to understand the actual fabrication issues that limit yield. Citing only die size is naive and misleading.

- edge defocus issues have been solved, which is why it (reportedly) no longer takes more than one patterning step to produce a 35mm sensor- but multiple exposures didn't do anything to yield, it just spoke to process improvements- and it meant that you could expose more smaller sensors in a step- so it's not unique to larger sensors. It still doesn't address yields, but it's not a large sensor only improvement.

The Canon APS-H sensor used in the 1D (not 1Ds) body is, according to Canon's white paper, the largest die size that can be printed with one exposure. Their full frame sensor is printed with 3 exposures, but these are 3 smaller reticles than the single APS-H reticle because the FF sensor is not 3 times the size of the APS-H sensor. Canon solved the edge defocus issue by exposing the die 3 times, but the APS-H sensor is more sensitive to edge defocus.

Now are you saying that 3 separate exposures with smaller reticles did nothing to improve Canon's yield on FF sensors? Wow. I really need a reference for that.

What part of "to achieve parity" don't you understand? Your mythical, but unknown "leap" isn't realistic as far as I can see.

Because I don't think you're really looking. You really seem fixated on the notion that nothing can be done to improve yield on FF sensors, so the industry might as well throw up its arms and give up. That's a really wonderful attitude...

But again, it does nothing to address yields, so it's a strawman- more 35mm sensors means even more APS-C sensors, larger wafers isn't a sensor yield issue, it's a sensors-per-process-step issue.

But it does reduce cost because the number of good die per wafer increases. After all, we are talking about bringing down the price of FF sensors. That can be done by yield improvement and by more die per wafer. I'm surprised you didn't follow this argument.

Unlike your assertion that alignment issues aren't a big deal, Canon's last annual report trumpets their new solution for alignment. They're also focused on inspecting for defects up front- which doesn't exactly scream "way cool improvements in yields by solving a problem with the wafer" now does it?

There are two types of stepper alignment. One is die-to-die alignment. The other is die-on-die overlay alignment for subsequent mask layers. Both are well-understood problems and have been for a while. By using 3 exposures for a FF sensor, Canon has to accomplish both die-on-die and die-to-die alignment in each pass, but even this isn't new.

Again, we have to know what exactly causes yield loss on large sensors to have a meaningful debate. Talking about die size alone is devoid of reason.

Once again, even if 35mm yields doubled, they'd still be 30% behind APS-C yields from two years ago. Nobody seems to be trumpeting a 100% increaase in 35mm sensor yields in the last two years, and since only Canon and the MF manufacturers were doing 35mm processes in volume it's not like there was a huge universe of folks attacking the problem.

Now here we agree. As the market for full frame sensors grows, so will the R&D investment needed to reduce costs.

Feel free to show some real data and anything other than blind hope that the "industry" is going to "make a leap" that has no current substance.

Blind hope? Is that what John F. Kennedy had when he commissioned NASA to put a man on the moon? Is that what the semiconductor industry had when it solved the lithography problem for 45 and 32 nanometer? Yield of a full frame sensor is just another technological problem. You seem to suffer from blind pessimism.

 

[compuwar]

You keep missing the point. The argument that yield is related to die size is true, but die size is not the only factor, nor the most significant factor.

Die size is the most significant factor in price to yield issues.

http://www.naturescapes.net/092006/ej0906.htm

The bane of semiconductor manufacturing is die yield or in our context, sensor yield. Digital sensors, like all other semiconductor devices are made on wafers that have a number of sensors printed on them. But only a percentage of these are good and the rest are scrap. The percentage of good sensors as their size goes up is reduced dramatically.

My statement about 90% yield on long-life parts is exactly meant to assert that achieving high levels of yield on FX sensors should not be considered impossible. People who believe in the impossible are, in my view, useless people. They are the ones who thought a mission to the moon was impossible, and they would never have undertaken the challenges needed to make it a reality. The semiconductor industry has solved numerous very challenging problems, and is about to solve the challenges for 22nm. To think that they cannot bring FX sensor yields above 20% is lunacy.

Once again-Nobody but you has said that high yields on FX sensors are impossible. Nobody but you has said that sensor yields can't be brought above 20%- what has been said is that there is not a miracle over the horizon that will bring FX sensors to 90% yields soon. That's in terms of the current manufacturers who are actually manufacturing FX sensors. But even if they did, the economics still favor APS-C, and they will always favor APS-C.

Do you know why you cannot readily find yield numbers? Fab yield is one of the most closely guarded secrets.

Which is why sensor size must be extrapolated as a cost. However, yield increases are often trumpeted by fabs- in terms of imaging sensors there are basically five markets- medical imaging, space imaging, security devices, scanning and video/still cameras- in the first two, the cost of the sensor isn't as closely tied to the cost of the device as it is in the last three, and still cameras are the place where we can get the best data because of relatively low margins and high production rates.

The market for FX sensors is currently very small, which does not provide incentive for companies to pour resources into developing new process technologies. For general semiconductor devices, development of new process technologies is very expensive, and getting more so. Consortiums such as Sematech and IMEC are formed to spread the costs. Once the market for FX sensors grows, I see every reason for R&D expenses to rise to meet the demand for volume and price.

Again, any process improvements will move the entire market, not just the FX fab market.

Now explain why these fabrication problems don't affect smaller die sizes, but only affect large die sizes.

They don't- other than more process steps giving more opportunity to damage a wafer- but as I said in my last posting, I believe that Canon has reduced that in their newer processes. However *everything cited to date* has assumed _the exact same defect rates regardless of die size- that is, the process problems that cause defects are assumed to be the same for the same wafer size- that's why the economics are what they are.
[/quote]

Now let's say we have 100% yield on small sensors because we've made them really small. And we have 20% yield on large sensors because, well, because they're large. Now if I increase my yield on large sensors from 20% to 50%, will I increase my yield on small sensors from 100% to 120%? I would really like to see that!

Now you're just being asinine.

The point is clear: you have to understand the actual fabrication issues that limit yield. Citing only die size is naive and misleading.

No it isn't- everyone in the industry gives yield numbers based on defects-per-wafer and costs larger die sizes based mostly (but not completely) on the same number of defects-per-wafer. Obviously, if there are more process steps, or if there are process defects those make yields lower for larger dies, but there is very little inclusion of those issues in the overall math. If you normalize those process differences, so long as you've still got defects on a wafer, larger die sizes lose more yield.

The Canon APS-H sensor used in the 1D (not 1Ds) body is, according to Canon's white paper, the largest die size that can be printed with one exposure. Their full frame sensor is printed with 3 exposures, but these are 3 smaller reticles than the single APS-H reticle because the FF sensor is not 3 times the size of the APS-H sensor. Canon solved the edge defocus issue by exposing the die 3 times, but the APS-H sensor is more sensitive to edge defocus.

Now are you saying that 3 separate exposures with smaller reticles did nothing to improve Canon's yield on FF sensors? Wow. I really need a reference for that.

No, it didn't- because Canon wasn't then doing a single exposure- so it's yields have pretty-much always been from 3 exposures. My understanding is that they can now do a single exposure, which may have improvied yields due to fewer process steps and fewer alignment issues, but not by enough to make significant changes in the price of the sensor. APS-H sensors were the largest single-exposure sensor because they didn't lose yield because of defocus- or they would have done two exposures for APS-H.

Because I don't think you're really looking. You really seem fixated on the notion that nothing can be done to improve yield on FF sensors, so the industry might as well throw up its arms and give up. That's a really wonderful attitude...

You're trying to put words into my mouth again- you obviously have a reading comprehension issue, so I'm done. I never said "nothing can be done to improve yield," or that yield improvement shouldn't be advanced- your continuing attempts to twist my words makes any rational discourse impossible.

As we used to say on USENET, *plonk*.

 

[ksz]

^^^ Well, this has been pretty futile. I am tempted to rebut every statement of yours once again, but it will be a waste of my time.

 

[Hmac]

Name-calling and personality issues aside, I found the discussion interesting and educational. I don't think that sensor manufacturing plays as big a role in future camera development as consumer-driven market forces, but the conversation helps one understand the landscape.