{"id":484,"date":"2016-02-25T09:07:12","date_gmt":"2016-02-25T15:07:12","guid":{"rendered":"http:\/\/life.lithoguru.com\/?p=484"},"modified":"2016-02-25T09:07:12","modified_gmt":"2016-02-25T15:07:12","slug":"spie-advanced-lithography-symposium-2016-day-3","status":"publish","type":"post","link":"https:\/\/lithoguru.com\/life\/?p=484","title":{"rendered":"SPIE Advanced Lithography Symposium 2016 \u2013 day 3"},"content":{"rendered":"

On Wednesday morning I again went to see resist talks, but this time in the EUV conference (which is more than a little confusing, but I\u2019m glad I don\u2019t have to work out the details of which paper goes in which conference).\u00a0 Anna Lio of Intel gave a very nice talk entitled \u201cEUV Resists: What\u2019s Next?\u201d\u00a0 At the beginning of her talk she repeated the ASML marketing line about the HVM introduction of EUV:\u00a0 \u201cIt\u2019s a matter of when, not if.\u201d\u00a0 But that statement misses the whole point.\u00a0 When is<\/em> a matter of if.\u00a0 If EUV continues to be delayed, it will very quickly reach the point of not being viable commercially.<\/p>\n

That nit aside, it was a great pleasure to here Intel so emphatically promote a stochastic world view when it comes to EUV resists and their performance.\u00a0 Here is some of what she said:<\/p>\n

\u201cThink stochastics first.\u201d<\/p>\n

\u201cWe need new ideas and new resist platforms for stochastics.\u201d<\/p>\n

\u201cStochastics will rule the world.\u201d<\/p>\n

She said that not significantly improving over today\u2019s performance of stochastic-driven local CDU, local edge placement, and roughness is a \u201cdeal breaker\u201d for EUV.<\/p>\n

I only hope that the audience really listened and absorbed this message.\u00a0 She had a tone of frustration in her talk that the industry has not taken these ideas sufficiently seriously (I empathize – I only wish that Intel and other EUV customers had preached that message ten years ago).\u00a0 A reason for that frustration could be found in the next paper where SEMATECH provided historical data of EUV resist performance on a combined metric of resolution, sensitivity, and LER showing that there has been basically no improvement since 2012.\u00a0 This is not good.<\/p>\n

My frustration was extended to the next talk, where I heard again from Japan\u2019s EIDEC (EUVL Infrastructure Development Center) on their \u201cmetal resist\u201d.\u00a0 First, they refuse to say what metal is in their resist.\u00a0 This knowledge is absolutely necessary, in my opinion, before deciding to take this resist seriously.\u00a0 Also, they have repeatedly claimed that their resist has both high sensitivity and low LER, but all of their results show either<\/em> high sensitivity or low LER, but never both.\u00a0 There is disconnect between their marketing and their data.<\/p>\n

The next set of authors, from TOK, had no need to read my post from yesterday where I explained that high resist contrast is a necessary condition for reaching the lowest possible LER at a given dose and feature size.\u00a0 Their paper was all about how to combine stochastic thinking with conventional resist thinking about high contrast.\u00a0 I hope the new resist developers were listening to this veteran company.<\/p>\n

Togawa-san of Osaka University talked about acid amplifiers and how they might be able to reduce the effects of stochastic variation.\u00a0 He finally gave an explanation for how acid amplifiers might achieve this that makes sense.\u00a0 Acid amplifiers essentially multiply the acid concentration by some factor, allowing a lower exposure dose.\u00a0 Since the acid amplifier achieves higher acid levels, more quencher can be added to the resist formulation (which otherwise would have an unacceptable impact on sensitivity).\u00a0 The higher quencher levels lead to greater gradients of deprotection levels (or effective acid levels).\u00a0 But these acid amplifiers can, at best, act like a normal amplifier:\u00a0 amplifying the noise as well as the signal, plus adding its own noise source as well.\u00a0 Thus, the relative acid uncertain will go up.\u00a0 The real question is whether the higher chemical gradient can compensate for the higher acid uncertainty.\u00a0 The experimental data is ambiguous.\u00a0 Looks like a place where rigorous modeling could help.<\/p>\n

My final comment on the EUV resist talks is about Roberta Fallica of the Paul Scherrer Institut.\u00a0 This was his first talk at SPIE, and it was a fantastic one.\u00a0 Not only did he show very good measurements of resist absorption at the EUV wavelength (a difficult thing to do) compared to calculated values, but he proposed a novel way of interpreting their importance.\u00a0 He described the inverse of the absorption coefficient-dose to clear product as the volume of resist cleared by one absorbed photon.\u00a0 I\u2019m still trying to wrap my brain around that idea, but it is definitely worth thinking about.<\/p>\n

Outside of the resist world, I enjoyed a talk by Andrew Burbine, an RIT student working with Mentor Graphics.\u00a0 He discussed and implemented the idea of using Bayesian statistics to improve OPC model calibration.\u00a0 It gave an excellent tutorial on the idea, and provided an initial validation of its value.\u00a0 This looks like an idea worth pursuing.<\/p>\n

In the afternoon Juan de Pablo of the University of Chicago gave an excellent invited talk on directed self-assembly (DSA) modeling.\u00a0 An while there was a time conflict, I caught half of an invited talk by David Pan (my University of Texas colleague) on how shrinking standard cells makes accessing them (through connections called pins) increasingly difficult.\u00a0 Thus, we often don\u2019t get the area size benefit from the shrink that we expected.<\/p>\n

My favorite quote of the day (heard at a hospitality suite):\u00a0 \u201cWhen you take a picture without light, don’t blame the film.\u201d \u2013 John Biafore.<\/p>\n

On a different topic, someone attending this meeting for the first time asked me why there were so few women here.\u00a0 This is not a new comment.\u00a0 While those of us who have worked in the industry and attended this meeting for many years may be used to it, from an outsider\u2019s perspective the lack of gender diversity at the Advanced Lithography Symposium can be jarring.\u00a0 It is pervasive, from the conference leadership and ranks of SPIE fellows to the speakers and attendees.\u00a0 It is also true at other lithography meetings that I attend, and I think in the semiconductor workplace as well.\u00a0 What is it about lithography and the semiconductor industry that attracts so few women?<\/p>\n

Finally, since the topic keeps coming up, let me say this:\u00a0 my Lotus is safe and secure in my garage.\u00a0 Vivek Bakshi and I resolved our bet on EUV lithography last year, and you can read about it here<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

On Wednesday morning I again went to see resist talks, but this time in the EUV conference (which is more than a little confusing, but I\u2019m glad I don\u2019t have to work out the details of which paper goes in which conference).\u00a0 Anna Lio of Intel gave a very nice talk entitled \u201cEUV Resists: What\u2019s […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-484","post","type-post","status-publish","format-standard","hentry","category-general"],"_links":{"self":[{"href":"https:\/\/lithoguru.com\/life\/index.php?rest_route=\/wp\/v2\/posts\/484","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lithoguru.com\/life\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lithoguru.com\/life\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lithoguru.com\/life\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lithoguru.com\/life\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=484"}],"version-history":[{"count":1,"href":"https:\/\/lithoguru.com\/life\/index.php?rest_route=\/wp\/v2\/posts\/484\/revisions"}],"predecessor-version":[{"id":485,"href":"https:\/\/lithoguru.com\/life\/index.php?rest_route=\/wp\/v2\/posts\/484\/revisions\/485"}],"wp:attachment":[{"href":"https:\/\/lithoguru.com\/life\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=484"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lithoguru.com\/life\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=484"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lithoguru.com\/life\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=484"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}