田中秀治研究室 ~Student Page~

Chemnitzer Seminar 2017 @Fraunhofer ENAS

Dear Tanaka Lab’s student blog reader,

This is Salman, an M2 student who have stayed at Fraunhofer ENAS in Germany for the past 5 months. Here I would like to report about the so called Chemnitzer Seminar 2017, which was held just before my departure back to Japan.

On 13-14 June 2017, I had a chance to attend the Chemnitzer Seminar in Fraunhofer ENAS, Chemnitz, Germany. This seminar is held annually as an exchange meeting between Fraunhofer ENAS, or in particular its Department System Packaging, and its collaborators. This year, Tanaka-sensei is one of the speakers, as the collaboration between Fraunhofer ENAS and Tohoku University has a long history.

The seminar starts at noon on 13th. It was opened by an opening speech by Dr. Maik Wiemer, the head of the Department System Packaging. He introduced the activities in the department, highlighting the achievement in during the past one year. He also introduced the Fraunhofer Project Center, which is a group within our laboratory under Froemel-sensei, in Sendai and its activities.

Opening Remarks
Chemnitzer Seminar 2017 opening remarks by Dr. Maik Wiemer.

The second speech was from Tanaka-sensei. He introduced research activities in our laboratory, highlighting the MEMS application for robotics development. Tactile sensor system and its large scale integration (LSI) sensor platform is offered as a solution for a high density sensor distribution for robots, which potentially leads to the higher level of human-robot interaction. A high performance whole angle gyroscope is also offered as a solution for the stability of robot movement.

Tanaka Lab Introduction
Tanaka-sensei introduced our lab at the end of his presentation.

The focus of the Chemnitzer Seminar is in the current development of packaging technologies. It covers a wide area from the development of functional materials, deposition technologies, additive manufacturings, bonding technologies, trough silicon vias (TSV) and their applications for various purpose. From this seminar, I could get many insights, not only about the development of the technologies, but also some technical knowledge.

For instance, in a presentation by Dr. Anke Sanz-Velasco, IMT AG (Switzerland), I got to know about advanced glass processing techniques, especially glass patterning using oxygen rich Cr and HF dry etching. In another presentation by Mr. Hubner from Leibniz-institut (Germany), a technology to reduce the electron beam writing time with variable shaped beam is proposed. In his proposal, his team has demonstrated a time reduction from several years to several hours in an attempt to pattern a complicated design.

A trend of smart system for agricultural sector is also proposed by Dr. Woodhead from Lincoln Agritech (New Zealand). His proposal also included a call for collaboration to commercialize their work. It was very interesting to know that it is also possible to monitor the amount of N2 fertilized as well as soil moisture level to achieve a smarter irrigation system. These functions are realized by microwave sensor they developed.

There was also a presentation from Mr. Frank Roscher. He is one of two group leaders in the Department System Packaging of Fraunhofer ENAS who has received the Fraunhofer awards for his achievement in research as well as customer relation. I am actually working under his group during my stay. His main research interest is about the development of functional materials for microsystem packaging. And in this seminar, he introduced his work on the development of an aerosol jet printing technology to realize a 3D film membrane package. The package has a function as a security protection. When something penetrates the membrane, the security system will work, that the confidential data are kept safe.

Finally, the first day was closed by the presentation from Prof. Schulz about ongoing project in ENAS. The project is about a transportation card, which now is normally using the tap in tap out method. A new system which does not require tapping is proposed. The challenges are that everything, including sensors, actuators and power supply, have to be placed in a thin chip.

The second day starts from the morning with several presentations on the biomedical appications of smart systems. Biomedical equipments are often bulky and expensive, thus, only good hospitals have such facility. However, the idea of smart system using microsensors has fostered the idea of the development of wearables, or even implantable equipments. To realize that purpose, many researchers are working together. Of the devices developed are ultrasound assisted micro-endoscopy for diagnostic and therapeutics inside the human body by Fraunhofer ENAS, a wearable electroencephalogram (EEG) device developed by eemagine (Germany), and an optical sensor developed by Shinko (Japan).

Coffee Break
There is coffee break for the participants and presenters to exchange ideas or build a network in the middle of each session.

Overall, I think it was a good opportunity for exchanging results, as well as opening new collaborations between institutes from various countries. For me, it was also another exposure to new technologies being developed around the world. The seminar has given me a new perspective of what kind of world that we are going to realize with the development of technology, in particular the smart systems’ approach.


At the end of the stay

Hello, I’m Koki Tanaka, D2 student, and currently in Germany.
I guess spring season was already coming in Japan.
In Chemnitz, I felt winter only 1week, because it was very worm winter in this year.

さて、ケムニッツFraunhofer ENAS研究所における私の滞在も終了し、今はベルリンで日本へのフライトを待つ日々です。
Now, my stay in Chemnitz has finished.
I’m waiting for the flight to Japan in Berlin.
I’d like to turn around the half year of my stay.

The first day in Chemnitz, it was around 35℃ even in September.
As usual, I got lost my way.

The first month was spent to get used to make a living in Chemnitz.
In other words, only one month was required to get used anywhere.

It was also same to the researching.
There were some different points between ENAS and Tohoku University.
In Tohoku University, experiences of manufacturing process were more important.
On the other hand, investigation and planning were more important in ENAS.
I was particular about making by myself, so I needed long time to get used to ENAS researching.

Initially, I could not make sufficiently progress in searching papers and planning experiments.
I could get used these works after 2 month later.
Then, broken tools were also started working, so my research was started progressing well.

I also got used to transportation and communicating in Germany then.
A student card of TU Chemnitz is also working as a train free pass in Saxony, so I enjoyed trips on Saxony cities.
Saxony has many historical places, so every city has at least one of historical building and emotional episodes.

Near the end of the stay, I worked harder to finish all experiment.
ENAS was closed at 8:30 pm, so I waked up earlier when I had many works to do.
This habit was a good point compared to the habit when I was in Japan.

One day, based on this habit, I waked up and went to sightseeing before dawn, but every shop was closed.
Of course, it was.
I enjoyed the view.

Now, I’m writing this article.
If I looked back, there are many many flaws, such as mistakes in the research and places I could not be visited…

However, surely I got good experiences, and it might not be obtained without this stay.
At least, I can feel some changes in my mind, and I can recommend having an experience of going abroad.

Additionally, the stay made me refreshing.
I was bored staying the same place.

I and Kaneko-kun prepared the manual for living in Chemnitz, but currently Japanese only.
Some formalities, living information and good spot for sightseeing are explained.
I hope it makes stays easier not only for visitors, but also for stuffs in ENAS.

Thank you for your time.
See you again.

Night view from the office in ENAS
Normally no one stayed such late time


Research stay in Chemnitz -2015 winter-

現在,ドイツのFraunhofer ENAS研究所に滞在しております.
I’m Koki Tanaka, a doctoral student.
I’m staying Fraunhofer ENAS in Chemnitz, Germany.

Already 3 and half months have passed since I started to live here.
I’m feeling colder than Sendai, but similar to Hokkaido.

Outside is cold, but inside of houses are warm thanks to good heating systems.
I don’t know why Japanese heating systems are poor (except Hokkaido).
Maybe they prefer feeling each season. It is called “wabi-sabi”.

Before research talking, I’d like to show my sightseeing.

At first, I went to Erzgebirge which forms border between Germany and Czech Republic.
It is the mountain and also the forest.

This is surface side.
There were conifer trees (kind of pine), and it was great place for hiking.


I also went to underground side of the mountain.
It was known as a mining area. Today, we can see mining place and still workable old machines.

These machines were working with big sound. Then, big sound resonates in the tunnel.
We could not hear any other sounds completely.
I attended the tour with Germany guide, but the portable sound player with English guide is available.
If you can catch the guide sounds despite big sounds from machines, it would be available.


Next is an industrial museum in Chemnitz.
We can find the oldest and the newest machines such as cars, motorcycles, steam engines and so on.
Today, Chemnitz is a famous area of machining tool industry, which derived from weaving machine industry.
This history is similar to one of the most famous Japanese automobile company.


I felt everyplace is tidy and clean, and everything is systematic in Germany.
There are no annoying things.
I’d like to keep in my mind this culture.

In researching, sometime I made and tried something without any plan, but now I learned the importance of planning.

田中(秀)研究室とFraunher ENASとでは,研究施設やその利用法などといった様々な点において多くの相違点がありました.
I found many many differences between S. Tanaka Lab. and Fraunhofer ENAS.
It was good for me to know these differences through real experiences.
There are also big differences between just knowledge and knowledge with experiences.

Thank you very much Kurth-san for your guides and pictures.

Thank you for your time.
See you again.


Stay in Germany 3: Experiment in ENAS

Hi, everyone. I’m Kaneko, a master student of Tohoku University and Technical University of Chemnitz (TU-Chemnitz).
It has already passed 4 month since I arrived at Germany. I spend so fulfilling days that it feels very long for me. I research and study on weekdays, and enjoy trips on weekend.

This is old buildings in Dresden, Sachsen. We can go to all cities in Sachsen for free with my student card. Dresden is so beautiful city that I visited many times.

さて、Stay in Germanyシリーズの3回目ですが、今回は予告通りENASの研究施設について述べたいと思います。といっても、装置1つ1つを解説するのではなく、東北大学からENASに来て感じたことを中心に書きたいと思います。今回の内容は私がENASに来た時から共有しようと思っていたものです。ですので今回は頑張って日英両方で書きます。
For the third topic of Stay in Germany series, I’d like to introduce experimental system in ENAS. I mainly discuss the difference between Tohoku University and ENAS which I found. This topic is what I really wanted to share you since I came here.

ENASのラボ (Laboratories in ENAS)

まず最初に、ENASの実験施設(ラボ)について述べます。余談ですが、東北大の研究室でいうところのラボ(例 Tanaka Lab.)という言葉は、こっちでは「実験室」を意味します。クリーンルームもラボです。反対に、居室のような空間は「オフィス」と呼びます。
First of all, I will mention laboratories in ENAS. By the way, it looks “laboratory” means experimental room in ENAS. So cleanroom is also called lab. Laboratories in Tohoku University (e.g. Tanaka Lab.) are called “group” or “office”.
There are three cleanrooms and many small laboratories in ENAS.

Cleanroom no.1 is located in other building where is almost 300 m far from ENAS. There are equipments of PVD, CVD, thermal oxide and draft chambers inside. And operator office is also located here so we visit here when we apply wafer process. I will mention it later.

Cleanroom no.2 is located in next building. Some equipments like Deep-RIE, CVDs as well as Photolithographies are inside. Its clean level is so high that the rules regarding clean wears or carrying wafers are strict. There is even a changing room for next changing room for clean wears. And wafers must be carried through transfer room.

Cleanroom no.3 is located 3rd floor in ENAS. There are some bonders, chemical draft chambers, film deposition as well as CMP equipments inside. This cleanroom is similar to our Kyodo-to-cleanroom.

Small labs are located underground/ground/1st/2nd floors in ENAS. Although its size is same (or half) as experiment room in MNC in Tohoku University, there are many kinds of equipments because each department has their own labs. The number of small labs is over 20.

When you transfer your wafer to other labs, you must seal it as following. When you transfer the wafers to cleanroom no.2, you have to pack double and remove outer package at transfer room then remove inner package inside cleanroom.


You have to get electrical access key to enter all labs and offices. You have to take a safety lecture from responsible person (ENAS staff) of each lab to get the access right. Therefore you cannot enter all labs. It is different from MNC in Tohoku University. It usually does not matter but we cannot get equipments easily like MNC. The best way to get some equipments earlier is just to ask staffs, I think. They will give you some advices or find them for you.

The responsible persons usually manage their labs. They maintained consumes, chemicals, equipments, medical box (later discussion). It is different from Tohoku University where every user is required to maintain experimental environment. By the way, all offices, labs and other rooms are cleaned by cleaning company. This might be a culture difference.

ENASのウェハプロセス (Wafer processes in ENAS)

Main process line in ENAS is for 6 inches or 8 inches wafer. In my opinion, the most difference between Tohoku University and ENAS is operator system. Most wafer processes like CVD, PVD, thermal oxide, etching as well as dicing are conducted by operators. Even observations like SEM/AFM are also their work. Researchers design devices on wafers and evaluate device after it arrives. Most of European research centers seem to apply these operator systems. However I have to mention that you have to manage the wafer process by yourself even on operator system. We must not rely on operators all.

Let me explain using a simple example of bonding device. Assume the device is fabricated through thermal oxide, metal sputtering, photolithography, metal etching and dicing. First we fill in program sheet for operators. (English is possible) We have to describe in detail on the sheet for example; how much thickness is needed for thermal oxide/ metal/ photo resist, which materials do you need, which layout data is used for the photo mask, so on. Then we visit operator office to apply. There are two kinds of operators; one operators are for process fabrication and the others are for process management. We visit latter operator and explain the process flow. I often use some pictures for better understanding. They have process conditions and check our program sheet with them. After some corrections the wafer process start.

The advantage of operator system is that most process conditions are established and well controlled. They select proper process conditions from the information of program sheet.

オペレーターによるプロセスで特に重要なのが、「実験計画」だと思います。6インチウェハなので、当然ですが一つ間違えるとすべてがダメになります。ですから本当にその設計でよいのか、実験に必要な枚数のチップを得るにはウェハは何枚必要なのか、十分に計画する必要があります。また、オペレーターは多忙です。大勢の人がプロセスを依頼しているので当然です。ですから納期がそれなりにかかります。プロセスを少しでも短くする工夫が必要です。コストの観点からも、不必要なプロセスを踏まないよう、注意が必要です。そして何より、ドイツ人はAfter 5や休暇を大切にします。残業や休日出勤という発想はありません。(なお、ENASは午後8時半以降や休日は閉鎖されます。)オペレーターが数週間の休暇中なんていうのもざらです。残念ながら担当オペレーターがいないと、そこでプロセスはストップします。
In my opinion, one of the most important things about operator system is experiment plan. You have to take care planning like each chip design, its layout and the number of wafer for the experiment, so on. You also have to mind operators are busy because many researchers request their process. Therefore it’s important to reduce processes as much as possible to advance the delivery as well as to save fabrication cost. Moreover you have to keep in mind that German people value after 5pm or holidays. They never work overtime or work weekend. (ENAS is closed after 20:30 and week end.) It is quite common for researchers or operators to take vacation for several weeks. Unfortunately, the process will be stopped if a responsible operator is absent.

As you see above, the disadvantage of operator system is the process speed is limited by operators. I often felt frustrating it at first because I would finish in shorter period by myself. But it’s nonsense. Therefore you have to take care what is really important for your experiment.

It is also important to check current situation of process by yourself frequently. Once I had an experience that the process had stopped long time at one process because of machine trouble. I would take countermeasures earlier if I had checked more frequently. This is the meaning of that you have to manage your wafer process by yourself. Especially this is more important for short-time visitor like me.

It is really good experience for me to research at ENAS because I can learn different experiment styles here during my master program. At first I made many mistakes because I behave as I’m at Tohoku University. But I learned a lot of things from these failures. In my opinion, it is important to put myself in different environment to expand my view. In addition, I got the confidence to communicate in English. At first I was uneasy to research, or even live in Germany without Japanese. Nowadays, however, I don’t feel any uneasiness to that. I enjoy English at research, discussion, travels as well as parties with friends. I’d like to value these experiences after I go back Japan.

ENASの安全設備 (Safety measures in ENAS)

In my opinion, safety measures also important as well as experimental system. In Tohoku University, there are many safety measures like several safety lectures (gases, chemicals, and experiment in cleanroom, so on), some safety rules (prohibition single experiment in night or holidays) as well as shared “Hiyari-hatto” (Incident). In this section I will introduce some of safety measures in ENAS.

・安全講習 (Safety lectures)
There are two kinds of safety lectures in ENAS; one is for all researchers/operators/students. The other is for each laboratory which I already mention above. The former lecture is in more open atmosphere compared to Japan. Unfortunately, however, I missed most of contents because all information is written/ spoken in German. (I asked the presenter to send English version later.) We have no choice but to estimate from pictures or gestures if we face presentation with unknown language, and result in poor understanding. We also have to keep in mind it in Tohoku University.
The latter lecture is one by one style with a responsible person of a laboratory. They tell us some rules regarding equipments or chemicals, safety equipments like hand shower, eye shower and medical box, and emergency actions. We are allowed to have a access key after the lecture.

・医療ボックス (Medical box)
ENASの安全設備で特徴的なのが、この医療ボックスだと思います。クリーンルームを含むすべてのラボに必ず設置されており、中には包帯、ガーゼ、消毒液、絆創膏、緊急連絡先一覧、記録用紙などが入っています。フッ酸を扱うラボには必ずフッ酸用の医療ボックス(Hexafluorine® Solution)もあります。万が一なにかで怪我をしたときでも、近くにこのような医療ボックスがあれば迅速な対処を施すことができますね。緊急連絡先にはENASスタッフの連絡リストも含まれています。なお、ドイツの法律で、この医療ボックスの記録用紙に記入すると、怪我の完治まで保険がきくそうです。医療ボックスと同様に、ハンドシャワーやアイシャワーもすべてのラボに備わっています。(一部消火器も)
In my opinion, this medical box is the most characteristic safety measures in ENAS. This box is located all of laboratories in ENAS. There are bandages, gauze, antiseptic solution, adhesives as well as the list of emergency contact numbers in the box. The medical box for hydrofluoric acid (Hexafluorine® Solution) is also prepared in laboratories where hydrofluoric acid is stored. If some accidents occur, we can take prompt action with this case. By the way, German law gives assurance for insurance until complete cure if the injured person signs a document in this box. Hand shower and eye shower are also set all laboratories.


・薬品、劇物 (Chemicals, deleterious substances)
アセトンやエタコールなどの有機系は耐火性の薬品庫に保管されています。これは誰でも取り出すことができます。フッ酸をはじめとする薬品は、専用の棚に二重に保管され、資格を持ったオペレーターでしか扱うことができません。劇物の薬品の詰め替えなども、専門のオペレーターによって行われます。また、ENASでは強酸・強塩基などを誤ってこぼした際の中和剤に Chemizorb_Rという吸着処理剤を使用しています。こぼれた薬品を吸着剤で覆うことで、吸着と中和が同時に進み、最後に後始末をすればいいようです。
Organic chemicals like acetone or ethanol are stored inside fireproof shelf. Everyone can use these chemicals. Deleterious chemicals like hydrofluoric acid are stored in double chemical box and only limited operators can use it. Refilling of these deleterious chemicals is also done by these operators.
In ENAS, an adsorption treatment agent, “Chemizorb_R”, is used as neutralizer for strong acid or strong base in spill case. Chemizorb_R absorbs and neutralizes these chemicals simultaneously. After that we remove absorbed Chemizorb_R.


・ガスその他 (Gases and others)
Most of gas wirings are set by companies. Gases are also exchanged by operators who have license. All gas lines are monitored by gas sensors every time. In case of gases leak, these gas flows will shut off automatically. Besides gases, vacuum lines, cooling water (or daily tap water), air conditioners and waste chemicals are also monitored every time. They are all supplied by equipments on underground floor in ENAS except for waste chemicals. Only some responsible person can access these areas on underground. In my case, Dr. Froemel kindly guided.

・電気遮断スイッチ (Breaker switch)
Breakers are set at the entrance of all laboratories. All the users are told its location for emergency at safety lecture.

I introduced some of safety measures in ENAS above. Even though we have different systems, I hope we can find feedbacks from each other, because the number of people who use machines or chemicals in Tohoku University are much more than that of in ENAS.

おまけ1 (Extra 1): TU-Chemnitz

Finally I would like to introduce some areas in TU-Chemnitz.


Here is a pathway along lecture room (right side). You can often meet some art paintings, pictures and bust in this modern buildings, as well as ENAS. We can enjoy European atmosphere.


Here is one of large lecture rooms. I take a lecture here. By the way, people in German academic field often hit tables by back of their hand several times instead of clapping. At first I felt like they were protesting.


It is monument of professor in front of lecture room. He sometimes changes his pose.


Here is Mensa which have cafeteria, café, bar, supermarket, so on. I usually go here for lunch. Ice cream stand is also popular in this season. (1 EUR)

おまけ2 (Extra 2)


It was on my birthday in this month. Some members held birthday party for me. (By the way, Tim Jonny, who is right front in the picture, will stay at our laboratory from this October.) We enjoyed home-made beer at the nice terrace in front of Chemnitz city hall in sunny weather. Danke!!



Stay in Germany 2 : ENAS

Guten Morgen.
Good evening.

I’m Kaneko, M2 student.
From this time, I’d like to introduce Fraunhofer Institute for Electronic NANO Systems (ENAS) where I am staying now.
Before the main topic, I mention Fraunhofer briefly. Fraunhofer is founded in 1949. At present, it maintains 66 institutes and research units, with nearly 24,000 staffs. They undertake applied research that drives economic development and serve the wider benefit of society. ENAS is one of the institutes of Fraunhofer, founded in 2008 by Prof. Dr. Thomas Gessner.

Some of you know the name of “ENAS” because Esashi/Tanaka lab has been collaborating long time, but I believe few members, especially students, know what they are researching well. So, I will share what I learn here as much as possible.

Today’s topic is departments in ENAS.
Here is ENAS building in TU-Chemnitz. After sunset, these building light-up. I heard this design shows printed circuit board.

There are six departments belonging to ENAS; Multi Device Integration, Micro Material Center, Printed Functionalities, Back-End of Line, System Packaging and Advanced System Engineering. The common strength of all departments is the development of smart integrated systems for different applications. These systems combine nano-micro devices like MEMS with electro components, high technologies and smart products. ENAS covers vast field related to integrated technologies; for example, high-precision sensors for industrial applications, sensor and actuator systems with control units and evaluation electronics, printed functionalities like antennas as well as material reliability research for microelectronics and micro system technology. Their application areas are semiconductor industry, medical engineering, mechanical engineering, security sector, automotive industry as well as aeronauts.

Then, I will explain technologies of each department. Of course, I cannot introduce everything, so I will write some characteristic topics and notes. Please search if you find interesting topics. I attach homepage address of each department.

1. Multi Device Integration
(Head of department: Prof. Dr. Thomas Otto)
HP: http://www.enas.fraunhofer.de/en/departments/MDI.html

This department focuses on the integration of MEMS/NEMS into functional modules and development of MEMS/NEMS using silicon based and non-silicon materials like polymer. In detail, this department combines following technologies;

MEMS/NEMS design
They combine modeling and multi simulations for analysis and optimization of MEMS/NEMS.
Design: Electronic (Analog, digital, mixed signal, PCB layout, Software programming), RF-MEMS, optical designs, photomask design, so on.
Simulations: Structural analysis, electromechanical coupling, fluid-structure coupling, micro fluidics and acoustics, thermo mechanical stress, electromagnetic simulation for RF-MEMS and antennas.
(Fig.1: Design and Simulation in the Fraunhofer ENAS MEMS/NEMS lab.)

Infrared MEMS spectrometer, Temperature Scanner, chemical sensors for Food studies, environmental, condition and process monitoring, medical diagnostics, so on.

Fluidic integration and system technologies
Microfluidic systems enable faster analysis, lower sample volumes, new methods of detection, advanced cooling mechanisms and chemical reaction control for many applications like medical diagnostics, health care, food and environment monitoring and chemical processing.
(Fig.2: Microfluidic cartridge with integrated, gel based low-cost pumps for in-vitro diagnostics.)

Nanocomposites is hybrid materials which combine polymeric matrices with nanoscale inclusions such as particles, fibers or tubes. They realize different functions from original materials. In this department, humidity sensors and piezoresistive composite sensors for the detection of forces are developed.

Measurement, test and characterization
・A method for the extremely fast determination of dimensional and material parameters based on a combination of Finite Element Method (FEM)
・Measurement of Eigenfrequencies
・Test equipment for MEMS motion, dymanic deformation, RF-MEMS

System integration
Condition monitoring system of sealing rings: This system can prevent unnecessary downtime and personnel cost for maintenance measures, plant failures due to sudden failure of components, unnecessary expenses for preventive component change.
Laser Micromaching: They also realize highly precise structures in almost all kinds of materials by ultra short pulse laser. They customize the laser for bulk structuring, drilling, cutting, selective layer structuring and laser welding.
(Fig.3 : Condition monitoring system of a sealing ring.)
(Fig.4 : Silicon parts, fabricated by ultra short pulse laser micro machining.)


2. Micro Materials Center (MMC)
(Head of department: Prof. Dr. Sven Rzepka)
HP: http://www.enas.fraunhofer.de/en/departments/MMC.html

This department has long research history about material reliability. Therefore, they have strength in many fields regarding material evaluation. Regarding reliability,

Microreliability and nanoreliability of components, systems and complete applications
(Fig.5 Nondestructive analysis and fully parametric modeling of real micro and nano structures.)

Thermo-electro-mechanical reliability analysis

・Reliability for avionics and space applications

・Microreliability for electronics and smart sensor systems in fully electrical but also in hybrid and ICE vehicles.

・Solder reliability for micro nano interconnects

・Reliability for packaging in the micro/nano integration field

3D integration technology
More than Moore technology
(Fig.6 Fracture mechanics at nanometer scale.)

And they also analyze material properties like;
・Physics of failure analysis, fatigue and creep analysis

・Design for manufacturability and reliability based on numerical methods fully calibrated and validated

・Local deformation analysis

microDAC/nanoDAC: Thermo-mechanical failure, movements, deformations in structure and materials of micro/nano size.
fibDAC: Stresses on micro and nanotechnology devices
Micro/Nano Raman
EBSD(Electron Back Scatter Diffraction Patterns): Maximum spatial resplution in crystalline materials
(Fig.7 microDAC- Deformation analysis at crack tip.)

・Analysis of internal stress with highest special resolution
Thin film stacks
Back end of line structures


3. Printed Functionalities
(Head of department: Prof. Dr. Reinhard Baumann)
HP: http://www.enas.fraunhofer.de/en/departments/PF.html

Some people should know printing technology; gravure, offset, flexo and screen printing as traditional processes, and ink-jet, xerography as digital processes. These technologies can transfer ink dots onto even fiber based substrates, plastic foil and sheet metals. Their products will be equipped with functionalities not only color but electrical conductivity, semi conductivity, optimized porosity, and electric power. With these functionalities, they will be able to perceive their surroundings, save these data and communicate them via computer network with other members of the Internet of Things (ITO). In this department, they develop following technologies;

Printed thin film battery
This is one of the applications of printing technology for Microsystems and consumer electronics.
(Fig.8: +/- 15 V printed battery)

Radio Frequency Identification Technology (RFID)
RFID is used in vehicle tracking system like the access and exit controlling of cars in car parks and industrial sites, for example. About this RFID Antennas technology, they published interesting journals. Their work is also applied in car access system of ENAS. Now, RFID is also recognized as key technology in industry 4.0 in Germany.
(Fig.9: Vehicle tracking system in ENAS.)

Hybrid Roll-to-Roll Manufacturing System
They developed hybrid printing machine which consists of unwinding, web guide roll, optical mark detection, rotary screen printing, ink-jet printing, LED UV curing, IR heating, photonic sintering and rewinding. Its web speed is up to 20 m/min.
(Fig.10: microFLEXTM machinery (3D Micromac).)



4. Back-End of Line
(Head of department: Prof. Dr. Stefan E. Schulz)
HP: http://www.enas.fraunhofer.de/en/departments/BEOL.html

The researches of this department are helpful to our laboratory. Back-End-of-Line technologies comprise all processing step from contact level up to the completely processed wafer prior to electrical testing. With downscaling of the transistor, the resistance-capacitance product (RC-product) of the interconnect system increases, resulting in strongly increasing signal delay. Therefore, they research suitable materials, advanced processing methods and analytical tools as well as novel modeling and simulation approaches. Their technologies are following;

CVD : barrier, metal, dielectrics
ALD : metal, metal oxides, nitrides, Carbon nanotubes 
Electrochemical deposition : Cu, Ni, Au, Sn
Electroless deposition : Ni, Au
Dry etching : metals, dielectrics
CMP : Si, SiO2, barrier/copper film system, Al, various glasses
Grinding : Si, glass, lithium niobate, lithium tantalate, ceramics
(Fig. 11: Selective grown CNTs coated by ALD.)

Interconnects for Micro and Nano Electronics
Low-k and Ultralow-k dielectrics: Shrinking pattern size is getting serious effect on RC delay (signal delay). Low-k materials which have lower dielectric constant enable to decrease RC delay as well as power consumption and crosstalk.
Air gap technology: The k-value of air gap is lower than other materials. That's why it is called ultra low-k material. They developed some approaches of air gap formation and evaluated them. They published many journals about low-k dielectrics.
Copper Damascene Metallization 
Carbon nanotubes(CNTs): CNTs are a well known material in nanotechnology for their unique mechanical, electrical and thermal properties. They can withstand extreme current densities and thermal load. Also, they have high electron mobility and high current carrying capacity, as well as high sensitivity to external strain, thermal load, illumination and chemical environment. 
(Fig. 12: Air gap formation between copper interconnects.)

Materials and Metallization for NEMS

Technologies for 3D integration in MEMS Applications

Through Silicon Via (TSV)
Wafer thinning
Alignment and bonding
(Fig. 13: TSV filled with copper by electrochemical deposition.)
(Fig. 14: Optimized etching profile for TSVs with an aspect ratio of 20.)

Simulation of devices, CVD/PVD processes
(Fig. 15: Simulation stress field within a MOSFET transistor caused by deposition of a nitride stressor film.)

By the way, I’m now taking one lecture given by Prof. Dr. Shulz, “Advanced Integrated Circuit Technology”. It covers every specific processing, simulation, modeling, integrated circuit technologies as well as 3D technology, including above technologies. It is really informative because it also covers state-of-the-art technologies which are applied industry or are developing. I’d like to study a lot from this class.


5. System Packaging
(Head of department: Dr. Maik Wiemer)
HP: http://www.enas.fraunhofer.de/en/departments/SP.html

This is just the department which I am now belonging. This department focuses on versatile packaging technologies from zero-level packaging up to multi-level packaging. MEMS Packaging is important technology because it accounts for from 20 up to over 90 percent of manufacturing cost. They also focus on micro and nano patterning of surface areas in micro system technology.
There technologies are following;

MEMS packaging and 3D integration
Wafer level packaging
TSV(Through Silicon Via)
Wafer, chip, and wire bonding
Die separation
Electrical, mechanical, and thermal connecting
Characterization (hermiticity, strength, ultrasonic and IR microscopy.)
(Fig.16 : Wafer level bonding of pressure-sensor.)

Wafer bonding
Standard bonding: silicon direct bonding, anodic bonding, eutectic bonding, adhesive bonding, glass frit bonding.
Low-temperature bonding: reactive bonding, laser assisted bonding.
Other bonding: Polymer bonding, thermo-compression bonding.

The importance of the wafer bonding technology for both semiconductor industry and micro systems technology has been steadily increasing for a number of years. Add to standard bonding methods, many bonding methods have been developing so far. We need to select proper bonding method with the bonding device property. For example, low temperature bonding is often necessary for heterogeneous devices. Intermediate layer, hermiticity, homogeneity and bonding strength are also important factor.
(Fig.17 : MHz ultra sonic cleaning for wafer bonding, and Mr. Froemel.)

Nano scale effects
They analyze nano scale intermediate layers and layer systems that are deposited with PLD, PVD and Aerosol jet technology. Moreover, surface and material effects are investigated and characterized based on metallic nano structures for new bonding techniques.

Imprint technologies
Nano imprint technology has the advantage of high resolution, high throughput, little dimension error and low cost. First, embossing or imprinting micro and nanostructures are molded (Master). Then, the patterns are transferred to photo resist and exposed. Finally, micro and nano patterns are formed by removing master tool. They research not only include the development of embossing process but also the design and production of some kinds of tools like silicon master tools, tools with patterned photo resist or soft tools, so on.
(Fig.18: Sub-micron patterned resist via nano imprint lithography.)

Surface modification

Plasma activation treatment

Aerosol jet and Screen printing
Aerosol jet allows the maskless and non-contact deposition of a wide range of functional liquids in flexible patterns. Additional to the printing of organic materials, adhesives and biological relevant materials, it allows the printing of conductive structures and other functional materials.
Screen printing is used for selective patternings of interlayers for wafer bonding by coating paste like materials on a flexible screen.
(Fig.19: Screen printed glass paste structures)

Chip bonding
Flip-Chip (FC)
Chip-to-Chip (C2C)
Chip-to-Wafer (C2W)
Multi-Chip-Module (MCM)
Chip-on-Board (COB)
Surface Mounted Devices (SMD)


6. Advanced System Engineering
(Head of department: Dr. Christian Hedayat)
HP: http://www.enas.fraunhofer.de/en/departments/ASE.html

This department is located in University of Paderborn. The main efforts of this department are the design, the simulation and the characterization of micro and nano complex electronic systems. (Electromagnetic compatibility, electromagnetic reliability, signal integrity, radio frequency, so on.)
Their technologies are following;

Advanced 3D near-field scanning
(Fig.20: Near-field measuring system. )

Wire-less energy transmission
(Fig.21: Demonstrator of parallel communications and wireless energy transmission.)

Mobile wireless and RFID smart sensor systems for harsh environment

Advanced modeling and analysis of EMC and SI-effects

System modeling and simulation

(Fig.22: Modeling of a wireless energy transmission; current distribution within the activated transmitting antennas.)

Model-based development methods for custom specific heterogeneous systems

RF and EMC measurement on wafer-level

Multiphysics modeling and simulation

(Fig.23: 3D-Packaging: numerical simulation of electronic properties.)


As I mention above, each department has own research field in smart integrated systems and own business partners. At present, ENAS collaborates with over 150 partners from industry worldwide. Not only industry field but some universities and research institutes collaborates ENAS. Tohoku University has been one of the main partners of basic research for long years.
Their annual report (2014) shows their growth on business, finance as well as human resources on every year. Their investment is also enlarging. For example, in 2014, ENAS invested 2.8 million EUR in equipment investment as well as building activities. Moreover, 4.05 million EUR were invested for purchasing a nanolithography system which enable the usage for both direct write and mask making for a large variety of applications in industry and applied research.
So, their business scale is expected to enlarge steadily in the future.

This is the end of this report.
Thank you for reading such a long report.
What I’d like to say in this report is ENAS covers so many and so interesting technologies for smart integrated systems that it is really informative for me, and you.
I will study much more during my stay.
I’m glad if you are interested in some technologies from this report.

Next topic will be about experimental environment in ENAS.
I’ve already entered their cleanrooms and labs, and found some differences from our laboratory. I will report experimental systems in ENAS with the differences from Tohoku University.


・Fraunhofer ENAS homepage
・ Brochures of the departments(All pictures are reproduced from here.)
・Fraunhofer ENAS Annual Report 2014