When talking about the ASML EUV light source, John Larkin talked about >envisioning spherical balls of molten tin in a hurricane.
They'd rotate, so they wouldn't be spherical, become oblate spheres at
quite low rotational rates.
https://diposit.ub.edu/server/api/core/bitstreams/78365ce1-8c0c-46af-b48e-0a3432e3da7d/content
talks about rotating droplets of liquid helium as they move from a
oblate to an prolate shape.
I wonder if a polarised laser beam could have got the tin spheres to
spin faster and move into helpful shapes.
It's the sort of fundamental question John might have asked.
On Sat, 30 May 2026 16:19:18 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
When talking about the ASML EUV light source, John Larkin talked about
envisioning spherical balls of molten tin in a hurricane.
They'd rotate, so they wouldn't be spherical, become oblate spheres at
quite low rotational rates.
https://diposit.ub.edu/server/api/core/bitstreams/78365ce1-8c0c-46af-b48e-0a3432e3da7d/content
talks about rotating droplets of liquid helium as they move from a
oblate to an prolate shape.
The tin droplets are shot out of a tiny nozzle, squeezed out by some
sort of piezo vibrator. I don't think they rotate much but they sure
wobble.
I wonder if a polarised laser beam could have got the tin spheres to
spin faster and move into helpful shapes.
It's the sort of fundamental question John might have asked.
One big issue for tin droplet detection is that the sphere isn't a
nice round sphere, but has multiple vibration modes. There is a mess
of higher frequency ripples sloshing all over the liquid surface
scattering light everywhere. The detector output looks like a lot of
noise.
There are several drops in mid-air at once and when the giant CO2
laser hits one, the shock wave whacks all the incoming droplets and
makes things worse. They call it fratricide.
The detector was all analog and had to be done fast. It couldn't be
the classic constant-fraction discriminator that physicists love so
much.
It didn't help that Certain Parties vetoed some of our better ideas.
john larkin <jl@glen--canyon.com> wrote:
On Sat, 30 May 2026 16:19:18 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
When talking about the ASML EUV light source, John Larkin talked about
envisioning spherical balls of molten tin in a hurricane.
They'd rotate, so they wouldn't be spherical, become oblate spheres at
quite low rotational rates.
https://diposit.ub.edu/server/api/core/bitstreams/78365ce1-8c0c-46af-b48e-0a3432e3da7d/content
talks about rotating droplets of liquid helium as they move from a
oblate to an prolate shape.
The tin droplets are shot out of a tiny nozzle, squeezed out by some
sort of piezo vibrator. I don't think they rotate much but they sure
wobble.
I wonder if a polarised laser beam could have got the tin spheres to
spin faster and move into helpful shapes.
It's the sort of fundamental question John might have asked.
One big issue for tin droplet detection is that the sphere isn't a
nice round sphere, but has multiple vibration modes. There is a mess
of higher frequency ripples sloshing all over the liquid surface
scattering light everywhere. The detector output looks like a lot of
noise.
There are several drops in mid-air at once and when the giant CO2
laser hits one, the shock wave whacks all the incoming droplets and
makes things worse. They call it fratricide.
The detector was all analog and had to be done fast. It couldn't be
the classic constant-fraction discriminator that physicists love so
much.
It didn't help that Certain Parties vetoed some of our better ideas.
I recall one such instance
On Sat, 30 May 2026 21:41:47 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
john larkin <jl@glen--canyon.com> wrote:
On Sat, 30 May 2026 16:19:18 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
When talking about the ASML EUV light source, John Larkin talked about >>>> envisioning spherical balls of molten tin in a hurricane.
They'd rotate, so they wouldn't be spherical, become oblate spheres at >>>> quite low rotational rates.
https://diposit.ub.edu/server/api/core/bitstreams/78365ce1-8c0c-46af-b48e-0a3432e3da7d/content
talks about rotating droplets of liquid helium as they move from a
oblate to an prolate shape.
The tin droplets are shot out of a tiny nozzle, squeezed out by some
sort of piezo vibrator. I don't think they rotate much but they sure
wobble.
I wonder if a polarised laser beam could have got the tin spheres to
spin faster and move into helpful shapes.
It's the sort of fundamental question John might have asked.
One big issue for tin droplet detection is that the sphere isn't a
nice round sphere, but has multiple vibration modes. There is a mess
of higher frequency ripples sloshing all over the liquid surface
scattering light everywhere. The detector output looks like a lot of
noise.
There are several drops in mid-air at once and when the giant CO2
laser hits one, the shock wave whacks all the incoming droplets and
makes things worse. They call it fratricide.
The detector was all analog and had to be done fast. It couldn't be
the classic constant-fraction discriminator that physicists love so
much.
It didn't help that Certain Parties vetoed some of our better ideas.
I recall one such instance
RS, the co-founder of Cymer, reprimanded me for giving him your book.
He said he worked his way through the thing cover to cover and didn't
get anything else done for three days.
I recall that they were making a few watts of EUV in those days. I
think they are pushing a kilowatt now.
I've never understood how they can do nanometer lithography with what
is basically a fuzzy-ball incoherent light source.
On 31/05/2026 8:19 am, john larkin wrote:
On Sat, 30 May 2026 21:41:47 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
john larkin <jl@glen--canyon.com> wrote:
On Sat, 30 May 2026 16:19:18 +1000, Bill Sloman <bill.sloman@ieee.org> >>>> wrote:
When talking about the ASML EUV light source, John Larkin talked about >>>>> envisioning spherical balls of molten tin in a hurricane.
They'd rotate, so they wouldn't be spherical, become oblate spheres at >>>>> quite low rotational rates.
https://diposit.ub.edu/server/api/core/bitstreams/78365ce1-8c0c-46af-b48e-0a3432e3da7d/content
talks about rotating droplets of liquid helium as they move from a
oblate to an prolate shape.
The tin droplets are shot out of a tiny nozzle, squeezed out by some
sort of piezo vibrator. I don't think they rotate much but they sure
wobble.
I wonder if a polarised laser beam could have got the tin spheres to >>>>> spin faster and move into helpful shapes.
It's the sort of fundamental question John might have asked.
One big issue for tin droplet detection is that the sphere isn't a
nice round sphere, but has multiple vibration modes. There is a mess
of higher frequency ripples sloshing all over the liquid surface
scattering light everywhere. The detector output looks like a lot of
noise.
If the droplets had been injected into a strong magnetic field, that
would have acted to damp the ripples. Make it a rotating magnetic field
and you'd have spinning droplets with fixed axis of rotation.
There are several drops in mid-air at once and when the giant CO2
laser hits one, the shock wave whacks all the incoming droplets and
makes things worse. They call it fratricide.
The detector was all analog and had to be done fast. It couldn't be
the classic constant-fraction discriminator that physicists love so
much.
Why not? They can be pretty fast, but they do depend on delaying a
portion of the pulse.
On Sun, 31 May 2026 12:39:10 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 31/05/2026 8:19 am, john larkin wrote:
On Sat, 30 May 2026 21:41:47 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
john larkin <jl@glen--canyon.com> wrote:
On Sat, 30 May 2026 16:19:18 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>> wrote:
When talking about the ASML EUV light source, John Larkin talked about >>>>>> envisioning spherical balls of molten tin in a hurricane.
They'd rotate, so they wouldn't be spherical, become oblate spheres at >>>>>> quite low rotational rates.
https://diposit.ub.edu/server/api/core/bitstreams/78365ce1-8c0c-46af-b48e-0a3432e3da7d/content
talks about rotating droplets of liquid helium as they move from a >>>>>> oblate to an prolate shape.
The tin droplets are shot out of a tiny nozzle, squeezed out by some >>>>> sort of piezo vibrator. I don't think they rotate much but they sure >>>>> wobble.
I wonder if a polarised laser beam could have got the tin spheres to >>>>>> spin faster and move into helpful shapes.
It's the sort of fundamental question John might have asked.
One big issue for tin droplet detection is that the sphere isn't a
nice round sphere, but has multiple vibration modes. There is a mess >>>>> of higher frequency ripples sloshing all over the liquid surface
scattering light everywhere. The detector output looks like a lot of >>>>> noise.
If the droplets had been injected into a strong magnetic field, that
would have acted to damp the ripples. Make it a rotating magnetic field
and you'd have spinning droplets with fixed axis of rotation.
There are several drops in mid-air at once and when the giant CO2
laser hits one, the shock wave whacks all the incoming droplets and
makes things worse. They call it fratricide.
The detector was all analog and had to be done fast. It couldn't be
the classic constant-fraction discriminator that physicists love so
much.
Why not? They can be pretty fast, but they do depend on delaying a
portion of the pulse.
Too noisy. A proper droplet detector lowpass filters the worst noise
and then finds the pulse centroid, over a serous range of pulse widths
and amplitudes.
It's really a statistical game.
On 31/05/2026 1:26 pm, john larkin wrote:
On Sun, 31 May 2026 12:39:10 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 31/05/2026 8:19 am, john larkin wrote:
On Sat, 30 May 2026 21:41:47 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
john larkin <jl@glen--canyon.com> wrote:
On Sat, 30 May 2026 16:19:18 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>>> wrote:
When talking about the ASML EUV light source, John Larkin talked about >>>>>>> envisioning spherical balls of molten tin in a hurricane.
They'd rotate, so they wouldn't be spherical, become oblate spheres at >>>>>>> quite low rotational rates.
https://diposit.ub.edu/server/api/core/bitstreams/78365ce1-8c0c-46af-b48e-0a3432e3da7d/content
talks about rotating droplets of liquid helium as they move from a >>>>>>> oblate to an prolate shape.
The tin droplets are shot out of a tiny nozzle, squeezed out by some >>>>>> sort of piezo vibrator. I don't think they rotate much but they sure >>>>>> wobble.
I wonder if a polarised laser beam could have got the tin spheres to >>>>>>> spin faster and move into helpful shapes.
It's the sort of fundamental question John might have asked.
One big issue for tin droplet detection is that the sphere isn't a >>>>>> nice round sphere, but has multiple vibration modes. There is a mess >>>>>> of higher frequency ripples sloshing all over the liquid surface
scattering light everywhere. The detector output looks like a lot of >>>>>> noise.
If the droplets had been injected into a strong magnetic field, that
would have acted to damp the ripples. Make it a rotating magnetic field
and you'd have spinning droplets with fixed axis of rotation.
There are several drops in mid-air at once and when the giant CO2
laser hits one, the shock wave whacks all the incoming droplets and >>>>>> makes things worse. They call it fratricide.
The detector was all analog and had to be done fast. It couldn't be >>>>>> the classic constant-fraction discriminator that physicists love so >>>>>> much.
Why not? They can be pretty fast, but they do depend on delaying a
portion of the pulse.
Too noisy. A proper droplet detector lowpass filters the worst noise
and then finds the pulse centroid, over a serous range of pulse widths
and amplitudes.
It's really a statistical game.
You really do need to define what you mean by "too noisy".
You seem to be claiming that the signal you are looking at has range of >pulse widths, and you have to hit your droplet with your laser shortly
after the signal has peaked, independent of the shape of the rising edge.
Presumably you have one or more low powered light source illuminating
the volume where the tin droplet will appear, and several photodetectors >that can detect the light reflected off the droplet.
If the droplet is vibrating - as you say it is - each detector will see
an occasional photon as the droplet grows, and stop seeing them as the >droplet flies beyond the illuminated space.
Summing the output of several detectors should give you a tolerably >well-behaved signal.
The droplets aren't moving all that fast, so we aren't talking about >nanosecond signal processing here.
On Sat, 30 May 2026 21:41:47 -0000 (UTC), Phil Hobbs ><pcdhSpamMeSenseless@electrooptical.net> wrote:
john larkin <jl@glen--canyon.com> wrote:
On Sat, 30 May 2026 16:19:18 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
When talking about the ASML EUV light source, John Larkin talked about >>>> envisioning spherical balls of molten tin in a hurricane.
They'd rotate, so they wouldn't be spherical, become oblate spheres at >>>> quite low rotational rates.
https://diposit.ub.edu/server/api/core/bitstreams/78365ce1-8c0c-46af-b48e-0a3432e3da7d/content
talks about rotating droplets of liquid helium as they move from a
oblate to an prolate shape.
The tin droplets are shot out of a tiny nozzle, squeezed out by some
sort of piezo vibrator. I don't think they rotate much but they sure
wobble.
I wonder if a polarised laser beam could have got the tin spheres to
spin faster and move into helpful shapes.
It's the sort of fundamental question John might have asked.
One big issue for tin droplet detection is that the sphere isn't a
nice round sphere, but has multiple vibration modes. There is a mess
of higher frequency ripples sloshing all over the liquid surface
scattering light everywhere. The detector output looks like a lot of
noise.
There are several drops in mid-air at once and when the giant CO2
laser hits one, the shock wave whacks all the incoming droplets and
makes things worse. They call it fratricide.
The detector was all analog and had to be done fast. It couldn't be
the classic constant-fraction discriminator that physicists love so
much.
It didn't help that Certain Parties vetoed some of our better ideas.
I recall one such instance
RS, the co-founder of Cymer, reprimanded me for giving him your book.
He said he worked his way through the thing cover to cover and didn't
get anything else done for three days.
I recall that they were making a few watts of EUV in those days. I
think they are pushing a kilowatt now.
I've never understood how they can do nanometer lithography with what
is basically a fuzzy-ball incoherent light source.
On Sun, 31 May 2026 12:39:10 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 31/05/2026 8:19 am, john larkin wrote:
On Sat, 30 May 2026 21:41:47 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
john larkin <jl@glen--canyon.com> wrote:
On Sat, 30 May 2026 16:19:18 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>> wrote:
When talking about the ASML EUV light source, John Larkin talked about >>>>>> envisioning spherical balls of molten tin in a hurricane.
They'd rotate, so they wouldn't be spherical, become oblate spheres at >>>>>> quite low rotational rates.
https://diposit.ub.edu/server/api/core/bitstreams/78365ce1-8c0c-46af-b48e-0a3432e3da7d/content
talks about rotating droplets of liquid helium as they move from a >>>>>> oblate to an prolate shape.
The tin droplets are shot out of a tiny nozzle, squeezed out by some >>>>> sort of piezo vibrator. I don't think they rotate much but they sure >>>>> wobble.
I wonder if a polarised laser beam could have got the tin spheres to >>>>>> spin faster and move into helpful shapes.
It's the sort of fundamental question John might have asked.
One big issue for tin droplet detection is that the sphere isn't a
nice round sphere, but has multiple vibration modes. There is a mess >>>>> of higher frequency ripples sloshing all over the liquid surface
scattering light everywhere. The detector output looks like a lot of >>>>> noise.
If the droplets had been injected into a strong magnetic field, that
would have acted to damp the ripples. Make it a rotating magnetic field >>and you'd have spinning droplets with fixed axis of rotation.
There are several drops in mid-air at once and when the giant CO2
laser hits one, the shock wave whacks all the incoming droplets and
makes things worse. They call it fratricide.
The detector was all analog and had to be done fast. It couldn't be
the classic constant-fraction discriminator that physicists love so
much.
Why not? They can be pretty fast, but they do depend on delaying a
portion of the pulse.
Too noisy. A proper droplet detector lowpass filters the worst noise
and then finds the pulse centroid, over a serious range of pulse widths
and amplitudes.
It's really a statistical game.
On Sat, 30 May 2026 21:41:47 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
john larkin <jl@glen--canyon.com> wrote:
On Sat, 30 May 2026 16:19:18 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
When talking about the ASML EUV light source, John Larkin talked about >>>> envisioning spherical balls of molten tin in a hurricane.
They'd rotate, so they wouldn't be spherical, become oblate spheres at >>>> quite low rotational rates.
https://diposit.ub.edu/server/api/core/bitstreams/78365ce1-8c0c-46af-b48e-0a3432e3da7d/content
talks about rotating droplets of liquid helium as they move from a
oblate to an prolate shape.
The tin droplets are shot out of a tiny nozzle, squeezed out by some
sort of piezo vibrator. I don't think they rotate much but they sure
wobble.
I wonder if a polarised laser beam could have got the tin spheres to
spin faster and move into helpful shapes.
It's the sort of fundamental question John might have asked.
One big issue for tin droplet detection is that the sphere isn't a
nice round sphere, but has multiple vibration modes. There is a mess
of higher frequency ripples sloshing all over the liquid surface
scattering light everywhere. The detector output looks like a lot of
noise.
There are several drops in mid-air at once and when the giant CO2
laser hits one, the shock wave whacks all the incoming droplets and
makes things worse. They call it fratricide.
The detector was all analog and had to be done fast. It couldn't be
the classic constant-fraction discriminator that physicists love so
much.
It didn't help that Certain Parties vetoed some of our better ideas.
I recall one such instance
RS, the co-founder of Cymer, reprimanded me for giving him your book.
He said he worked his way through the thing cover to cover and didn't
get anything else done for three days.
I recall that they were making a few watts of EUV in those days. I
think they are pushing a kilowatt now.
I've never understood how they can do nanometer lithography with whatGerhard
is basically a fuzzy-ball incoherent light source.
On Sun, 31 May 2026 21:07:59 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 31/05/2026 1:26 pm, john larkin wrote:
On Sun, 31 May 2026 12:39:10 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 31/05/2026 8:19 am, john larkin wrote:
On Sat, 30 May 2026 21:41:47 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
john larkin <jl@glen--canyon.com> wrote:
On Sat, 30 May 2026 16:19:18 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>>>> wrote:
When talking about the ASML EUV light source, John Larkin talked about >>>>>>>> envisioning spherical balls of molten tin in a hurricane.
They'd rotate, so they wouldn't be spherical, become oblate spheres at >>>>>>>> quite low rotational rates.
https://diposit.ub.edu/server/api/core/bitstreams/78365ce1-8c0c-46af-b48e-0a3432e3da7d/content
talks about rotating droplets of liquid helium as they move from a >>>>>>>> oblate to an prolate shape.
The tin droplets are shot out of a tiny nozzle, squeezed out by some >>>>>>> sort of piezo vibrator. I don't think they rotate much but they sure >>>>>>> wobble.
I wonder if a polarised laser beam could have got the tin spheres to >>>>>>>> spin faster and move into helpful shapes.
It's the sort of fundamental question John might have asked.
One big issue for tin droplet detection is that the sphere isn't a >>>>>>> nice round sphere, but has multiple vibration modes. There is a mess >>>>>>> of higher frequency ripples sloshing all over the liquid surface >>>>>>> scattering light everywhere. The detector output looks like a lot of >>>>>>> noise.
If the droplets had been injected into a strong magnetic field, that
would have acted to damp the ripples. Make it a rotating magnetic field >>>> and you'd have spinning droplets with fixed axis of rotation.
There are several drops in mid-air at once and when the giant CO2 >>>>>>> laser hits one, the shock wave whacks all the incoming droplets and >>>>>>> makes things worse. They call it fratricide.
The detector was all analog and had to be done fast. It couldn't be >>>>>>> the classic constant-fraction discriminator that physicists love so >>>>>>> much.
Why not? They can be pretty fast, but they do depend on delaying a
portion of the pulse.
Too noisy. A proper droplet detector lowpass filters the worst noise
and then finds the pulse centroid, over a serous range of pulse widths
and amplitudes.
It's really a statistical game.
You really do need to define what you mean by "too noisy".
Seems obvious. Any amount of noise in locating the droplet reduces
wafer fab rate, and costs money. A CFD assumes that every pulse is
identical in shape and is noise-free. Nice theory.
You seem to be claiming that the signal you are looking at has range of
pulse widths, and you have to hit your droplet with your laser shortly
after the signal has peaked, independent of the shape of the rising edge.
We want to hit the droplet dead center, regardless of the optical uncertanties.
Presumably you have one or more low powered light source illuminating
the volume where the tin droplet will appear, and several photodetectors
that can detect the light reflected off the droplet.
The droplet passed through a sheet laser and reflected back into a
single photodiode. That's what we had to work with.
If the droplet is vibrating - as you say it is - each detector will see
an occasional photon as the droplet grows, and stop seeing them as the
droplet flies beyond the illuminated space.
Summing the output of several detectors should give you a tolerably
well-behaved signal.
The droplets aren't moving all that fast, so we aren't talking about
nanosecond signal processing here.
One microsecond is a tolerable error.
Of course ASML has moved on in 20+ years. I think (from public
sources) that they are now actively steering the droplets into the
target zone and surely have better optics.
The process is interesting if horrendous. There's stuff online and no
doubt patents. Turns out that wafer throughput is worth a lot.
Many people are spending big bucks to supersede the tin droplet
lithography thing... including just giving up on Moore's Law.
Personally, I don't much need bigger or faster CPUs or DRAM and I
don't need 10 terabytes of solid-state drives in my PCs. Maybe digital semiconductors are like dishtowels and hammers now, good enough.
I would like a sane and stable operating system.
Analog chips and power semiconductors have a way to go still, but they
don't need nanometer features.
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