{"id":541,"date":"2017-09-18T23:50:54","date_gmt":"2017-09-19T04:50:54","guid":{"rendered":"http:\/\/life.lithoguru.com\/?p=541"},"modified":"2017-09-18T23:50:54","modified_gmt":"2017-09-19T04:50:54","slug":"live-from-monterey","status":"publish","type":"post","link":"https:\/\/lithoguru.com\/life\/?p=541","title":{"rendered":"Live from Monterey"},"content":{"rendered":"

It has been eight years since I have been to Monterey to attend the Photomask Technology conference, commonly known as Bacus.\u00a0 The name Bacus comes from the group, the Bay Area Chrome User\u2019s Society, that originally sponsored the conference before merging with SPIE.\u00a0 Fall in Monterey is a beautiful time to think about masks!\u00a0 And this year we have the added benefit of thinking about Extreme Ultraviolet Lithography (EUVL) as well.\u00a0 The EUVL Symposium has also decided cooperated with SPIE to host their conference and this year the two meetings have been collocated for the first time.\u00a0 The result is a great synergy that makes both conferences better and gave me the necessary excuse to come again.<\/p>\n

The synergy seems to have worked, with 560 technical attendees and about 100 more attending just the equipment exhibit (significantly more people than the organizers had expected).\u00a0 I missed most of the first day of the photomask conference, but managed to notice how trendy the topic of machine learning has become.\u00a0 Unfortunately, this human didn\u2019t learn enough to make much sense of the machine learning papers.<\/p>\n

By Tuesday the EUVL conference had begun and I greatly enjoyed Greg McIntyre\u2019s keynote talk on EUV readiness for manufacturing.\u00a0 He pointed out how lithography scaling is slowing significantly, but that \u201cdevice cleverness\u201d is taking up the slack.\u00a0 These one-time innovations (like reducing the number of wire tracks making up the height of a standard cell) are helping to keep density scaling on track.\u00a0 The hope, then, is that EUV will arrive and get lithography pitch scaling back up to speed.\u00a0 Greg also clearly identified stochastic yield loss (extremes of roughness) as the number one problem facing EUV lithography.\u00a0 When printing lines and spaces (or contact holes) is there a process window that enables no bridges and no breaks (no \u201cmissing or kissing\u201d contact holes) at the same time?\u00a0 Some significant metrology innovations may be needed to answer this question.<\/p>\n

Many speakers discussed the imminent availability of the 250W EUV light source from ASML.\u00a0 Word on the street (or at least the conference halls) says Samsung is getting this first 250W source on their first NXE:3400B scanner.\u00a0 It has already shipped is supposed by be up by the end of this year with first results in early 2018.\u00a0 Everyone will be waiting anxiously for those results, I am sure.<\/p>\n

It is now clear that ASML is positioning the 3400 as the first EUV high-volume manufacturing (HVM) scanner.\u00a0 It looks like most of the NXE:3300 and 3350 tools will not be upgraded to higher source powers (many will stay at 80W) and will remain learning tools.\u00a0 The transition to a high power source is not an easy one.<\/p>\n

Besides the ability to handle higher source powers, the 3400 has other improvements, most particularly the ability to use extreme off-axis illumination (out to sigma of 1) with half the pupil fill ratio (20%) of previous generation tools.\u00a0 This will allow k1 as low as 0.32 (down from 0.38 or so).\u00a0 Zeiss has shipped 12 of the 3400 optical systems to ASML to date.<\/p>\n

Progress on EUV lithography as reported at the conference continues to be good, but none of the major risk factors have yet to be retired:\u00a0 sufficiently high source power to achieve good throughput, making and maintaining defect-free masks, and no yield loss due to stochastic effects in lithography.<\/p>\n

Erik Hendrickx of imec gave an update on their efforts to identify new absorber materials for EUV masks.\u00a0 The current tantalum absorber requires a thickness of 55nm, resulting in tall structures with undesirable shadowing effects for tilted illumination.\u00a0 Absorbers like Nickle or Cobalt could shrink the thickness below 35nm.\u00a0 The problem is etching these materials, and more work is still required.<\/p>\n

Heebom Kim of Samsung was optimistic about making defect-free masks.\u00a0 They have developed their own internal actinic mask inspection system that seems to have put Samsung ahead in EUV mask making.\u00a0 He claimed a current mask yield of 90%.\u00a0 They will also be getting the first EUV AIMS tool from Zeiss next year in order to qualify repairs with actinic light.\u00a0 But the combination of expensive inspection plus expensive repair verification plus expensive blanks will make EUV masks cost 8 times more than a 193 mask.\u00a0 Wow.\u00a0 I remember 15 years ago hearing promoters of EUVL saying that one of the big benefits of EUV will be cheaper<\/em> masks compared to 193.\u00a0 Whenever I feel a need for a good laugh, I go back and look at those early cost projects (when an EUV scanner was going to cost $20M, for example).<\/p>\n

The resist papers focused on understanding the exposure mechanisms of EUV resists, and on reducing roughness.\u00a0 Bits of progress were made on both fronts, but not nearly enough to reduce the risk of stochastic problems delaying or stopping the use of EUV in manufacturing.\u00a0 I\u2019m not sure what a major breakthrough in roughness management will look like, but it won\u2019t look like what we saw this week.<\/p>\n

ASML\u2019s one billion euro investment in Zeiss is showing tangible effects as construction has begun on new buildings for the manufacture of high-NA EUV optics.\u00a0 The NA=0.55 tool will be bigger than a freight train locomotive, and is essentially a two-story building.\u00a0 If you thought $140M was a lot for an NA=0.33 EUV scanner, imagine how expensive the new NA=0.55 tool will be.\u00a0 Then imagine higher.<\/p>\n

On Thursday I skipped over to the photomask conference to hear about progress on multibeam tools for mask making.\u00a0 Both IMS and NuFlare are making 50KeV e-beam lithography tools with 512X512 beams.\u00a0 IMS has hit the market first and has already shipped many tools targeting the N7 node.\u00a0 NuFlare has a beta version of their tool installed at Samsung, and so is behind IMS.\u00a0 Their tool is spec\u2019d for a higher resolution, however, and is geared toward the N5 node.\u00a0 The competition is encouraging and both companies are making great progress, enabling future mask making with improved specs and reasonable write times.<\/p>\n

Vinayan Menon of imec gave an extremely refreshing talk \u2013 an unfiltered look at one year in the life of an EUV scanner.\u00a0 It wasn\u2019t pretty.\u00a0 After installing an ~80W source on their 3300, imec faced a series of ugly trade-offs:\u00a0 either operate the source at near its full power and live with extremely low tool availability, or operate at a much lower power (below 30W) in order to keep the tool running and available.\u00a0 There was also a fairly significant reduction in source power over time that shows rate is not equal to actual power.\u00a0 Tool upgrades could help things, but those upgrades often took one or more months, so imec chose availability over peak performance.\u00a0 I found another point he made intriguing as well.\u00a0 A focus difference between the two chucks of the scanner was first detected as a systematic difference in linewidth roughness, suggesting that LWR might be a good focus monitor.<\/p>\n

The closing remarks of the EUVL Symposium always include the results of a survey of the conference steering committee.\u00a0 The basic survey asks which potential roadblock for EUV success is most concerning.\u00a0 This year\u2019s survey asked two questions:\u00a0 what is most concerning for initial HVM insertion, and what is most concerning for continued advances in EUV lithography beyond initial insertion.\u00a0 Interestingly, while the availability of a high-power source was considered the most pressing issue for initial HVM insertion, stochastic-induced variation was considered the number one issue for continued advances in EUV lithography.<\/p>\n

Unfortunately I missed quite a few good papers at the conference.\u00a0 I was busy rehearsing.\u00a0 For many of the EUV crowd new to the Bacus confer\"\"ence, it was a surprise to discover that the conference banquet on Wednesday night was followed by an entertainment show put on by members of our community (three of the six cast members had papers at the conference).\u00a0 This 40 minute show is skit humor, replete with singing, dancing, and often a fair amount of silliness (if you can\u2019t imagine what I\u2019d look like in an elf costume, don\u2019t try).\u00a0 I was very glad to be a part of the show this year after a 12-year hiatus.\u00a0 I hope the audience had half as much fun watching it as we did putting it on. \u00a0(Photo Credit: \u00a0Bernd Geh)<\/p>\n","protected":false},"excerpt":{"rendered":"

It has been eight years since I have been to Monterey to attend the Photomask Technology conference, commonly known as Bacus.\u00a0 The name Bacus comes from the group, the Bay Area Chrome User\u2019s Society, that originally sponsored the conference before merging with SPIE.\u00a0 Fall in Monterey is a beautiful time to think about masks!\u00a0 And […]<\/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-541","post","type-post","status-publish","format-standard","hentry","category-general"],"_links":{"self":[{"href":"https:\/\/lithoguru.com\/life\/index.php?rest_route=\/wp\/v2\/posts\/541","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=541"}],"version-history":[{"count":1,"href":"https:\/\/lithoguru.com\/life\/index.php?rest_route=\/wp\/v2\/posts\/541\/revisions"}],"predecessor-version":[{"id":543,"href":"https:\/\/lithoguru.com\/life\/index.php?rest_route=\/wp\/v2\/posts\/541\/revisions\/543"}],"wp:attachment":[{"href":"https:\/\/lithoguru.com\/life\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=541"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lithoguru.com\/life\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=541"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lithoguru.com\/life\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=541"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}