ADMETA has held its 30th anniversary in 2021. The history of ADMETA can be said to be the history of interconnect technology development itself.
On the occasion of the 20th anniversary of ADMETA, the ADMETA Committee published a booklet showing the history of the event. We are proud of the excellent content, which conveyed the exciting atmosphere of the period from the emergence of technology to that time.
To mark the 30th anniversary, we have decided to publish an English translation of a portion of the 20th-anniversary booklet, which had been published only in printed Japanese. Due to copyright restrictions, we are unable to publish the entire booklet, but we hope it will provide you with valuable information.
We have also added some information on the history of ADMETA over the last 10 years. Furthermore, we have received congratulatory messages from past chairpersons. We are pleased to publish them as well.
We hope that through this translation, young researchers and engineers will learn about the history of interconnect technology development and gain hints for new technology development.
I would like to express my gratitude to the past chairpersons for their assistance in translating the text into English. If there are any inappropriate parts in the translation, all the responsibility lies with translation in charge.
I sincerely hope that this translation will be useful to everyone who will be a part of the future history of ADMETA.
Translation in charge
ADMETA plus 2019 Chair
Shinji Yokogawa (The University of Electro-communications)
LSI (Large Scale Integration ) interconnect technology has made remarkable progress since the late 1980s. Advanced Metallization Conference: Asian Session (ADMETA) has been playing an essential role as the only international conference specializing in LSI interconnect technology in Japan, 18 years after the first meeting (1989), with the Tungsten Workshop held jointly between Japan and the United States as its predecessor. Initially held biannually, it has been organized every year since 1995. Moreover, recently the number of papers published has increased approximately to 50–60, with more than 200 participants. The operation of this society has been supported by significant donations from more than 20 companies, such as LSI device manufacturers, semiconductor equipment manufacturers, and material manufacturers, and the participation of several engineers and researchers. Expressing our gratitude to the people who have supported us to this date, we have decided to publish a commemorative magazine. In addition, the number of years is slightly different from the exact number, and the meaning of the 20th anniversary of the inauguration of ADMETA is also included in this booklet.
In this commemorative booklet, we focused on explaining the development of LSI interconnect technology. Over the past 20 years, the minimum line width of LSI interconnect has been miniaturized from 1.0 µm to approximately 60 nm, and the number of interconnect layers has increased from two to approximately ten layers. These goals have been achieved due to several significant technological changes. There have been limitless developments such as, from AI to Cu interconnects, the introduction of CVD (chemical vapor deposition) tungsten and CMP (Chemical Mechanical Polishing) , from etching (RIE) to damascene, low- dielectricuation films, from sputtering to plating. Several engineers who were active in the 1980s, which can be said to be the decade for the rise of multilayer interconnect technology, must be in their 50s and 60s, with many now retired from this technology. Earlier, we did not have the opportunity to read so much about the views of young engineers which is now possible through commentary articles with episodes. In the field of material technology, technologies that are judged to be unusable might suddenly come back into the spotlight due to advances in peripheral technologies. Several such anecdotes are included in this book, where the history of ADMETA and the development of interconnect technology are described in the first part, the abstract of the round-table discussion “The Rise of Multilayer Interconnection” is mentioned in the second part, and the third part includes the explanation by experts on the core technology field. I hope that you will feel comfortable and read it according to your interests. *)
Recently, Cu/low-k film interconnect technology has become more comprehensive, although problems such as low dielectrics still exists. In addition, new materials which break the performance limits of Cu interconnects are required. However, breakthroughs are rare. In addition, device companies are no longer able to afford R&D, with R&D shifting to consortiums, equipment, and material manufacturers. In the 1980s, device manufacturers worked in an environment where trial-and-error search experiments could be conducted, and supported the fundamentals of remarkable technological development. Nowadays, further development of interconnect technologies requires ideas beyond the boundaries of conventional technologies, a flexible activity environment at the individual researcher level, and active mutual exchange. To achieve this goal, I hope that ADMETA will be further developed as a place for associated researchers to meet and engage in lively discussions.
ADMETA Commemorative Issue Editorial Committee
Chairman, Shoso Shingubara (Kansai University)
*) Only first and second parts are available on the web. However, in Part I, figures are omitted due to copyright reasons.