[[extropy-chat] diffraction limit

[Brent Neal]

 (5/29/04 10:40) Dan Clemmensen <dgc at cox.net> wrote:

>The precision of the current phase-shift masks is also not the limiting 
>factor. The current limiting factor is the wavelength of the bulk light 
>source that can support parallel exposure. The industry tried to go from 
>193nm to 153nm, but this required CaF lenses, and these lenses turned 
>out to be impossible to build in production quantities. The industry 
>then began looking at other tricks. The current new technology is 
>"immersion imaging" wherein the air between the lens and the substrate 
>is replaced with water. This allows for tighter focusing.
>
>

 (5/29/04 7:44) Robert J. Bradbury <bradbury at aeiveos.com> wrote:

>Also, there was a lot of talk 3-5 years ago about the efforts to produce
>even shorter wavelength beams (effectively X-rays) and there were several
>reports if I recall correctly of capabilities of producing feature sizes
>as small as 10nm.  But I haven't heard anything about these recently.
>Do you know if these methods are still being worked on?


There is long term research going on at CAMD in Louisiana, Brookhaven in New York, and a Japanese facility into using synchrotron light for litho. This is, of course, predicated on the notion that the easiest way to "fix" the diffraction limit is to use a shorter wavelength! ;)  (Yes, phase shift masks are one way of dealing with the diffraction limit, but we're still reaching the limit of what can be done with UV resists, no matter how clever we are.) Of course, there are other problems with using synchrotron light - the cost of the facility for one and the fact that the wafers must be stood on end, which is a non-trivial engineering problem, as Dan pointed out. Our current stepper motors are not up to the job.  If using entangled photons can be done more cheaply than either synchrotron facilities or FELs, then I think interesting things are on the horizon. My guess is that, like so many other things we've seen that rely of entangled quantum states, we're quite a few years away from solving some of the basic engineering problems involved with using the science in a meaningful, profitable way.


 (5/29/04 14:41) Dan Clemmensen <dgc at cox.net> wrote:

>This requires 4 answers. Basically, the question is whether or not the 
>designer can use a classical analysis a quantum analysis, or both.

>(Can a real physicist please supply these dimensions?)

Dan, the value you are looking for is the "k," the dielectric constant of the material that is between the traces. The lower the k-value, the more resistive the material is to E-fields. In the good ol' days, we just used SiO2 as the dielectric. No more. Now, we have a whole host of low-k compounds (some of which are patented and/or tightly guarded secrets, such as some of the organosilicate glass compounds) are being using.

As I recall, you treat this as a form of the particle in an infinite square well problem, and compute the penetration into the barrier of the electron as a function of the dielectric constant (or rather, the permittivity of the material) fro


B
-- 
Brent Neal
Geek of all Trades
http://brentn.freeshell.org

"Specialization is for insects" -- Robert A. Heinlein