Talk:Extreme ultraviolet lithography

message: Finally, an accurate representation of EUV image formation mechanism!218.168.206.105 (talk) 19:55, 15 May 2008 (UTC)
thread_title: Illustration

message: The newly added phase defect plots are based on some simplifying assumptions, which are stated in the figures' descriptions. They may be updated in the future. Recent experimental data (stated in the article) appears to be more helpful in conveying the information, with less reliance on assumptions. Figures based on these data may in the future replace some of the figures relying on specific assumptions.Guiding light (talk) 12:40, 6 July 2008 (UTC)
thread_title: Phase defects

message: Sweet, this article is currently ranked 5th over at google.  Good job, everyone.the1physicist 02:54, 14 December 2005 (UTC)
thread_title:  General 

message: This article will be updated, mostly to make it more concise while keeping the main points to date.Guiding light 16:52, 20 January 2007 (UTC)
thread_title: Article update

message: EUV has uses other than lithography, like photoelectron spectroscopy. Maybe that warrants its own article? Some sections of this article can be subsequently moved over there.Guiding light (talk) 02:32, 23 May 2008 (UTC)
thread_title: New article on EUV only?

message: Using either Burn Lin's rigorous formula or the approximate paraxial formula for depth of focus, it is seen that by using double patterning and immersion lithography, the depth of focus is better than using EUV (see the table). Intel already uses double patterning for 65 and 45 nm, so it has no good reason not to stay with it through its 11 nm nodes, as guided by its SPIE 2006 presentation. Samsung and IM Flash, also using double patterning, probably to ~ 20 nm Flash. Other companies may be very different, not using double patterning right now. So for them it is a matter of can they afford the cost of double patterning.Guiding light (talk) 10:24, 27 August 2008 (UTC)
replies: text: June 2009 update indicates 22 nm will not be EUV and 15/16 nm node can also be done by 193 nm immersion with double patterning. EUV still behind at 24 nm.218.35.242.119 (talk) 11:53, 21 June 2009 (UTC)
thread_title: EUV has worse Depth of focus than 193 nm Double patterning

message: After much consideration, I removed graphs I generated for Wikipedia articles which bordered on possible publication material. I don't think it detracts from the article content, since the referenced contributions are not affected.Guiding light (talk) 16:01, 24 June 2009 (UTC)
thread_title: Graphs Removed

message: On the whole, I find this page to be very informative about EUVL.  The first comment in the General section that this page has many hits from google is well deserved.  However, I have several questions regarding the section on Unexpected Resolution Limits.  The overall problem that I have with a lot of this is that many of the references that are cited in this section are relevant for e-beam exposures with energies of 70 to 100 keV, for x-ray exposures with wavelengths around 1nm, or e-beam flood exposures (more typical of a SEM), and these results are directly cited to provide precise estimates how horrible the proximity effects in EUV will be.  These references are certainly relevant to EUVL because many of the exposure mechanisms are similar, but such results should not be quantitatively applied to EUVL because the energies are often several orders of magnitude higher.  For the casual reader (who will likely not read the references in detail), these comparisons will give the incorrect impression that there is a large body of scientific evidence that these proximity effects will make "the practical effective resolution to be at best ~30nm" (this is the last sentance in the first paragraph in the 'Proximity Effect (secondary electrons)' section).  Here is a detailed list of comments on some of the references:
* Ref 29 by Lee: exposure is by 100 keV beam. EUV photons have ~90 eV, so energy is off by 1000x.
* Ref 30 by Feder: exposure by 0.83nm x-rays (energy ~1.5 keV).  There is also no control in the experiment (a PMMA layer coated with ebrium and not exposed).
* Ref 31 by Carter: Exposure is by 1.3nm x-rays.  Second sentance in the citation states that "In a PMMA film, the image blur dur to these [photo and Auger] electrons is on the order of 5nm".  However, the more pessimistic interaction length of 50nm is cited, which is observed due to backscattering from a gold substrate.  The 50nm number is relevant in the Wikipedia article because a comparison is made with the results by Feder, but a more careful explanation of the experiment would be helpful to the casual reader.
* Ref 32 by Yamazaki: Exposure by a 70 keV ebeam with a beam diameter of 7nm.
* Ref 34 by Renoud: exposure by an electron beam.  Here they discuss charge build up that is similar to what is seen on a SEM when the substrate is an insulator.  I have not done the calculation, but it seems like that the charging due to EUV exposure would not be even wildly close to ebeam exposure doses.  (EUVL's big problem is lack of photons, after all.)
* Ref 36 by Kotera: This article is actually about EUVL (yeah!).  However, he states "It is shown that the maximum radial range of those electrons is about 30nm....  If we assume that the proximity effect can be neglected since the intensity is less than 0.001, 5nm is the maximum distance to be patterned by EUV exposure without a proximity effect correction."  Oddly, only the 30nm distance is cited in the Wiki article.
* Ref 38 by Kozawa: This paper is also about EUVL, and a point spread function for acid generation is presented.  The text in the article states that the "acid generation probability... has a maximum at approximately 3nm."  At the maximum, the probability is about 0.35.  Perhaps the 20nm range listed in the Wikipedia article corresponds to 0.01 probability in the tail of the distribution.
I think that there are a lot of people who don't know much about EUVL, and might visit this page to learn about it.  On one side, there are a lot of critics, and on the other side, a lot of people dedicated to making it work.  I am not actively working on these systems, so I am not an expert on whether it will go into production or not.  However, as it stands, this article does not appear to be very even-handed in it evaluation of the challenges faced by EUVL. Bluedog29 (talk)
: Bluedog thanks for your active pursuit of the details. Since the distances traveled by the electrons do not follow well-defined formulas such as the Rayleigh diffraction limit, but instead form a wide distribution from ~ nm to ~30 nm, the WORST CASE tail results ~30 nm must be used for the judgment because they result in the manufacturing losses. Kozawa and Kotera's results are still simulated, while the actual results in resist (mostly derived from electron beams) are more indicative. It doesn't matter if the low-energy electrons are generated ultimately by EUV, X-ray or other electrons.Guiding light (talk) 03:34, 16 May 2010 (UTC)
replies: text:  The loss of energy by an electron is by ionization or else (below ionization potential) by quasi-elastic phonon generation (very low rate of energy loss by electron this way). The continuous slowing down model is a classical, somewhat misleading picture. Electron capture does happen, in the end, when the electron is slowed down to <<1 eV. Guiding light (talk) 06:13, 21 June 2010 (UTC)

text: Bluedog, regarding just the specific sentence excerpt by Kotera, it only makes reference to the photoelectron energy deposition as drawn in Fig. 4, and has not yet accounted for the secondary electrons generated by that photoelectron (which spreads it further). Still, your point is well taken, it is really not for certain to pin down the resolution at ~30 nm at this point. But as an interesting footnote, the NXE:3100 preproduction tool has the resolution spec of 27 nm, far short of the expected optical resolution.Guiding light (talk) 02:01, 21 June 2010 (UTC)
thread_title: Questions regarding 'Unexpected Resolution Limits' Section

message: David, your points are really good. Although this article has focused on the mainstream EUV development, there is no reason not to mention them as alternatives, if there can be references cited for them. It looks like they should be considered (ifnot already) for X-ray lithography? We can refer to that article, and possibly explain with references why they haven't been practiced for EUV development yet.Guiding light (talk) 07:46, 1 February 2012 (UTC)
thread_title:  Other options for source and optics 

message: Another option would be to use a Fresnel wave plate.  I met a Russian who was developing such a thing for soft X-rays.  Its transmission might be even worse than that of a Bragg mirror, but it is less sensitive to material properties and therefore more durable.
An other thing that works for X-rays is a grazing angle reflector, but one might not be able to reflect much light that way.
David R. Ingham (talk) 22:02, 21 January 2012 (UTC)
thread_title: Optics

message: Can't one include something in the resist mixture that absorbs the euv with resonant photoelectric effect to shorten the range and modify the spectrum of secondary electrons?
* I recall reading a paper where doping with Br or some other element had this or similar effect. If I can get that reference, I can add it to this and the X-ray article. I was really hung up on the secondary electrons for some time. But in the end, can't really tell how many or how far. But most recent papers now say the acid diffusion in chemically amplified resists dominates anyway, so the whole issue is blurred (unintentional pun) anyway.Guiding light (talk) 07:51, 1 February 2012 (UTC)
thread_title:  EUV exposure of photoresist 

message: This material is too long, too terse, and too technical for the lead.  Just for example, "pellicle adder" is undefined.  
Should start by explaining what the contamination problem is, how it was resolved by other lithographic solutions, and why those approaches have not yet made the jump.  
The bulk of this material should then be moved to a section devoted to surmounting the appropriate contamination obstacle. — MaxEnt 18:20, 5 June 2017 (UTC)
thread_title:  Opaque pellicles in lead 

message: Hi, I removed these sentences "A further complication for EUV tool throughput is the ring shape of the exposure slit, in contrast to the conventional rectangular shape. Consequently, slit width and height are effectively confounded in a complicated fashion"  I checked the paper cited, and I can't find any reference to this shape and what problems it causes.  As such these sentences aren't adding much to the article. Mikeroetto (talk) 14:58, 4 July 2020 (UTC)
thread_title:  Slit Ring Shape 

message: You don't mind we use  template to describe EUV processs image more precisely? [14:03, December 18, 2021] AXONOV (talk) ⚑ 14:41, 18 December 2021 (UTC)
thread_title:  Image caption 

message: There is a paper by ASML that lists interesting facts about EUV systems: . AXONOV (talk) ⚑ 14:45, 18 December 2021 (UTC)
thread_title:  Facts about EUV systems 

message: It says US pressured ASML not to export EUV to China, which may well be true, but ASML did attempt to export EUV to China. The current phrasing suggests it was ASML's decision not to export. However, the only reason it ultimately did not happen, is ASML was denied an export permit by Dutch authorities, which also were pressured by US authorities to block the sale.  The license would have been necessary because the machines fall under the Wassenaar Arrangement, which limits the export of military and dual-use goods and technologies. 2001:1C06:280D:5B00:B05B:5D0E:CDDE:3873 (talk) 11:32, 15 August 2022 (UTC)
thread_title:  History 

message: "WPD", "WPM", "ArF", "SMO", "DOF" - these are totally unreadable for a casual reader, and the article itself introduces dozens of abbreviations, even these that are then never used again (e.g. LWR is defined once as Line Width Roughness in a paragraph, and then "LWR" is never used again in the entire article, or IC is defined in the summary, as one of the key things, and then... used only once throughout the article, where it could easily be "used for integrated circuits production" rather than "used for IC-production". Let the integrated circuits artile itself define "IC", there's zero benefit in introducing this abbreviation here. I think it peaked with SALELE, where it's defined twice and never used used as the abbreviation itself, lol).
Either use Template:Abbr, or Help:Explanatory notes or just don't spam the article with abbreviations all over the place. It's fine to use 2 or 3 of the same words more than one time without abbreviating them. It won't burn a hole in the database, and the article will be far more readable. Generally everything that's in headers (including table headers) or image captions would be best left without abbreviations that are only defined in one of the dozens of paragraphs of the article. If the abbreviation absolutely must be used for whatever reason - please, at least {{Abbr| it.SkywalkerPL (talk) 09:00, 10 March 2023 (UTC)
thread_title:  Fewer abbreviations in the tables and captions, please