My PhD topic - New material chemistry exploration for Extreme Ultraviolet (EUV) Lithography

Hello folks, 

I am currently a doctoral researcher at Interuniversity Mictroelectronics Center (IMEC) located in Leuven, Belgium. My PhD project is part of a Marie-Curie funded European project with the acronym ELENA (Low energy ELectron driven chemistry for the advantage of emerging NAnofabrication methods). Here is the link to the ELENA website: ELENA-eu.

Under this consortium, a team of 15 Early Stage Researchers (ESRs) have been hired by different European research institutes and universities for their PhD, with the research focus on two important nano-fabrication techniques namely, FEBID and EUV Lithography.

I am ESR number 12 and my work will be on EUV Lithography. The topic of my research is "New material chemistry exploration for Extreme Ultraviolet Lithography". I have presented a synopsis of my project work below. 

Photolithography has been the major workhorse responsible for the advancement of the electronics industry over the past few years. It is a nanofabrication process in which light is passed through a patterned mask onto a substrate (Silicon wafer) coated with light-sensitive material called ‘photoresist’. Then using a solvent called ‘developer’, the exposed part of the photoresist is removed and the pattern (from mask) is replicated onto the substrate. The substrate is further processed to produce integrated circuits (IC).

Photolithography is controlled by Rayleigh’s formula. Currently, a deep ultraviolet (DUV) light source (wavelength λ=193 nm) is used to produce patterns at a maximum resolution of 40 nm. To further push the resolution down to 10 nm range, the wavelength of the source light needs to be reduced to as low as 13.5 nm. This is when the process becomes Extreme Ultraviolet (EUV) lithography.

EUV lithography, which is still in the research phase, is deemed to be the future of the semiconductor industry. However, as we reduce the wavelength to 13.5 nm, the energy of the photons becomes so high, that we move from excitation chemistry (in DUV lithography) to radiation chemistry (in EUV lithography). This changes the chemical interactions happening between the photons and the photoresist. The obscure change in the chemistry results in the underperformance of the currently available state-of-the-art photoresists.

The major problem associated with the current systems of EUV resist is something known as RLS tradeoff. R stands for the resolution, which is the smallest feature size that can be printed using that material. L stands for line-edge-roughness, which is the deviation of line-space feature from an ideal smooth shape. And S stands for Sensitivity, which is the minimum exposure dose required to reach the resolution. It is proving to be impossible to improve two of the parameters without exacerbating the third (hence, a trade-off). This RLS trade-off is caused due to chemical variability at nanoscale level. Only through the fundamental understanding of the chemistry of the process, it will be possible to produce robust photoresist systems that can work efficiently for EUV lithography. The objective of this research project is to bridge this understanding.

The approach of this project is a combination of two ways: 1) To enhance our knowledge of fundamental chemistry happening at the nanoscale level during EUV-patterning (through fundamental experiments such as solid- and gas-phase reactions) and 2) To use that understanding to design and characterize novel and robust EUV photoresists systems (through understanding synthesis of novel EUV systems, EUV patterning using ASML NXE scanner, CD-SEM analysis and RLS characterization).

Expected results from the project is to get a better understanding of the fundamental chemistry and correlating that to the critical parameters of novel EUV resist systems.

My trip to Paris - 1 April 2018

Spending quite a busy life doing my PhD, Easter holidays came at a great time to take my mind off from work and go for a relaxing mini-vacation in the city of light. Paris.

My girlfriend and I planned this trip at the very last moment (2 days before the trip) and grabbed the quickly depleting bus tickets to Paris. It took us almost 4 hours by bus and we reached Paris on 31st March by 6 pm.  Weather was cloudy but pleasantly cold.

Metro was the best option to reach to our accommodation in the southern part of Paris. But somehow I  checked the wrong address and we reached the wrong place, although with the same name- 9 Place Victor Hugo. Apparently there are more than one "9 Place Victor Hugo" in Paris. I acknowledged my mistake and we finally got the right connection amidst the constant bickering of my girlfriend. We reached the right place finally at around 8:30 pm and met the host- sweet old man- retired french policeman- very amicable and happy person. He showed us the place and recommended some french restaurants nearby.

We quickly refreshed and left for dinner (a little too late~ around 10:30 pm), but the suggested restuarant wasn't open so we found an italian food truck selling freshly made pizza. The irony of eating italian food for our first dinner in france was too strong but sweet none the less.

We roamed around for a bit and then went back to get a good night sleep. It's going to be a long and fun day tomorrow...

Next morning, we left our place at around 11, and took the metro straight to the heart of Paris- to visit the well known Eiffel tower. With grey clouds in the background, there was something eerily beautiful about the wrought-iron structure. 

We decided to roam around the city and come back to Eiffel tower at night, to see it in its full-fledged glory. So, the next stop was Pont Alexandre III. Walking through the heart of the city and coming across the museum of war (with old tanks from world war 2 carefully placed in the huge garden), we reached our location. Pont Alexandre... a grandiose bridge with beautiful golden sculptures enhancing the beauty of river Seine. 

Next to the bridge was a huge public square named "Place de la Concorda", with a stark resemblance to the London eye. A giant wheel in the vicinity and the ever so majestic Egyptian "Luxor obelisk" gifted to France, the place looked surreal with 2 beautiful fountains. 

Post lunch, we headed to our next place "Basilica of Sacred Heart of Paris"- a beautiful catholic church located on the hill-top of Mont Marte. The climb of 300 stairs were filled with local bars and restaurants, with a lot of people enjoying their evening with good french wine and music. We went inside and prayed for a good 30 minutes while absorbing the beautiful interiors full of intricate idols, wall carvings and glass paintings.

After coming out, we spent some time drinking and enjoying the live/music in a nearby pub. I might add that my girlfriend found the singer quite charming.

Later we had a quick dinner, and went back to visit Eiffel tower. This time going past the security check and then reaching right under the lighted- tower. It looked quite adorable, with the flickering light show, changing colors and dark moonless night in the background. We sat there, for what was like an eternity, watching the symbol of love.

Finally headed back home, and slept in seconds, both quite exhausted from the day's outing but excited for the next morning.

Next  day, we visited "Louvre Museum",  home for the most famous painting in the world- the authentic- La Gioconda or what is commonly known as the " Mona Lisa". There were hundred- if not thousands- of people lining up to get a glimpse of the master piece. We went through the museum exhibits-  describing the history of the great Lovre museum and exhibiting artifacts and antiquities from early-European, Egyptian, Greek and Asian civilization, dating back from a few hundred BC to 20th century. There were also a vast number of french paintings from early 1600s to 1800s. I could only imagine the work and hardships required to collect and keep these artifacts in impeccable condition. Finally, after 4 hours into the museum, we found our way to the one and only "Mona Lisa". Although no where an art connoisseur, I couldn't help but notice the strokes of oil paint on wood as fresh as they were and her insincere smile (almost wicked) that has left the whole world wondering what was going through her mind at that exact moment.

After 4 hours of mind bending experience, we went for a short walk outside to relax and absorb everything we could. It was drizzling now, as we headed across to see the present law court of Paris, but formerly used as a detention center during the French revolution. 

Later, we went for dinner and went back to the huge public square "Place de la Concorda" to see the city of light in its full glory, after which we took the metro and went back to our accommodation.

Next morning, early bus back to Belgium as we bow out of the beautiful city of Paris.

Till we see again!

Graduation day! MS Chemical Engineering, Hamburg University Germany.

Hello volks!

I have been pretty busy with my PhD work lately. However, I got a good news that I thought needed sharing. 

After two and half years of hard work of writing and completing courses and exams, doing a project arbeit and finishing the master thesis, I finally received my Graduation certificate and an invitation to attend the Graduation ceremony at my university (Technical University Hamburg)

The ceremony is on 1st December 2017 and I am pretty pumped up about getting my degree and finally getting the tittle MS Chemical Engineering.

Just wish my parents could attend the ceremony...

Life in Germany- What to do after your German student Visa is approved?

Hey guys, What's up!

This is the 3rd chapter of the series- Life in Germany. This post is going to discuss the things that are important for a student who has already got his student visa for Germany. The previous posts discussing the requirements of getting admission in a German university and applying for a student visa can also be found by clicking on the link.

So here goes...

Chapter 3- Things to do once you get the student visa to Germany

That awesome feeling when after so many anxious moments, you finally lay hands onto your stamped passport. Flip through and you can see the short stay visa (valid for 90 days) firmly attached to one of the pages of your passport. This is the point where you take a breather and relax. May be go for a beer! You deserve it!

But what next? What are the things you should keep in mind? Don't bother, here is the list.

1) Look for an accommodation as soon as possible: There are many students who travel to Germany for higher studies. So finding an accommodation might not be that easy. You can contact the international office of your university and ask them for a room in one of the many student houses. This is the best option. The rooms are furnished, spacious, relatively cheap and very clean. You will get to know student from many different countries and the whole experience is worth it!

However, if you are too late to get an accommodation in one of the student houses. Don't worry. There are many private accommodations available online.

2) Get in touch with the student association: There are various student associations that are functional and very helpful in all the German universities (Example: Indian Student Association-TUHH). They will surely help you with the accommodation (in case you could not find a student room or a private apartment) and also pick you up from the airport when you arrive. Also, they conduct various cultural and induction programs where you can meet and get to know other fellow students. 

If the student association doesn't have a dedicated website, look it up on Facebook. Every student association definitely has a Facebook page.

3) Bring sufficient cash with you: Activating the blocked a/c takes some time (1-2 weeks), so bring enough liquid cash with you (~1000 euros). As you may have to pay caution deposit, 1st month rent and a nominal semester fees (approx 300 euros per semester) after coming to Germany.

Once you are here, you have to do the following tasks:

4) Get yourself registered in the city hall (Kundenzentrum): City registration is important when you arrive in Germany. Get an appointment within 15 days of your arrival by applying online to Kundenzentrum of your city (Example: Kundenzentrum Hamburg). You need the following documents:

i) Passport and Visa

ii) Rental agreement

iii) Completed application form (you can get the form online or at the city hall)

iv) 10-15 euros cash

Do not worry if you still do not have a permanent place, you can just show the rental agreement of temporary accommodation the first time. You will just have to go again for address change when you move into permanent accommodation (10 euros extra charge).

When you register at the city hall, you get a confirmation form (Anmeldebestatigung) which is needed to get the residence permit (long stay visa) and get the library card from your university.

5) Activate your blocked account: You can activate your blocked account at a nearby Deutsche bank by showing your passport and the blocked a/c confirmation letter. After that your a/c is activated in 3-4 hours and you will receive a debit card and TAN list at your registered address in 1-2 weeks.

6) Get a SIM card: Its best to get O2 prepaid sim in the starting. O2 to O2 call is free and almost everyone in Germany uses O2 service. You get the prepaid SIM for free and then you can charge it with 15 euros prepaid card. Later you can get a post paid O2 SIM if you want.

6) Get the student health insurance: There are many options (TK, AOK etc etc). Doesn't matter too much, they are almost the same. I had TK student insurance and I had to pay 90 euros per month through out my masters. So its quite expensive compared to other EU contries. 

Required documents: Admission letter from the university, Bank a/c details, phone number and confirmation letter from city hall (Anmeldebestatigung).

7) Register for the semester: Once you have the health insurance letter you can register for the semester at the admissions office of the university. You also need to show original documents (transcripts of your bachelor and school). After confirming the authenticity you will get an in-voice for the semester contribution which you can pay at the nearby branch of Deutsche bank. You will get a library card as well.

8) Apply for a residence permit: Once you register at your university, they make an appointment (or you haveto do it) at the nearby Kundenzentrum for you to go and get your long term stay visa (residence permit). You need to have the following documents:

i) Passport
ii) Confirmation of city registration (Anmeldebestatigung)
iii) Health insurance confirmation letter
iv) Student ID or certificate of enrolment
v) 2 biometric passport size photos
vi) Deutsche bank statement or blocked a/c letter
vii) Completed application form (which you can get at the office)
viii) Residence permit fees (approx. 120 euros)

After finishing all the required formalities, you will get a letter at your registered address (in 2-3 weeks) saying that your residence permit is ready and you can come and pick it up. You go the Kundenzentrum with this letter and you will receive your residence permit.

So these are the steps a student need to carry out after coming to Germany. I hope this was helpful. If you have further questions or feedback, you can comment below.

P.S.: The next chapter of the series- Life in Germany- is going to be Things to do and things to avoid once your semester starts! That will definitely be a much more interesting post I promise ;-)

Cheers!

Life in Germany- Applying for a study visa

Hey guys, 

In my previous post, I laid down the steps you need to concentrate on to get an admission letter from a German university. You can have a look at the post here. If you would like to add something please feel free to comment. 

This is the second post in series-Life in Germany-and today I am going to explain the procedure necessary for applying for a study visa to Germany. This step can be initiated once you get the admission letter from the German university.

So here goes...

Chapter 2: Applying for the Study Visa to Germany

Before I go into details, it's important to understand that the whole Visa procedure can take anywhere between a month to 3 months (some cases even more time) to initiate the process and get the Visa stamped. So keep that time scale in mind. 

Now, the documents you need to apply for study visa to Germany are following:

1)  A valid passport 

2)  Admission letter from the German university

3) Completed application form for applying for German student visa 

4) Three good quality passport size photographs with required specifications  -- (Don't bother too much about these specifications though, just tell the photo studio that you need these for visa process and they will give you high quality photographs themselves.)

5) Transcript of your academic records -- print outs of your bachelor, 12th and 10th mark sheets should be sufficient

6) Certificate of travel and health insurance for student -- You can get this very cheaply (approx. 1000 INR through any insurance company in India.)

7) Letter showing the proof of blocked account in Germany: It's mandatory to open a blocked account* in Deutsche Bank and transfer sufficient funds (~8400 euros) into that account. You will then get a confirmation mail from the Deutche bank branch in Germany that your blocked account has sufficient funds to cover your 1st year of studies. (Note: 8400 euros is for 1st year only). 

This can be done in two ways-

(i) open a bank account in one of the Deutsche bank branch available in India and then transfer funds into that. They will then open a blocked account in German branch and transfer the amount. In few weeks time (2-3 weeks) you get the confirmation mail. (I did this.)

(ii) Directly opening a blocked account in German branch can also be done. Simply download the application form from the Deutsche bank online. Fill the document leaving the date, place and signature. Get appointment from German consulate in India to get the attestation (Note: you have to fill the date, place and signature in front of the officer). Submit other necessary documents to the consulate and once your documents are verified and attested, you can transfer the funds into the Deutsche bank German branch directly. 

Complete information of this step can be found here.

8) A Demand draft (of ~4600 Rs-please double check) in favor of German embassy or respective consulate. This is non-refundable in case your visa application gets rejected.

9) A cover letter explaining the reason for your visit and the length of your stay in Germany.

11) German language proficiency certificate (if your course is in German; not needed for international courses!)

12) A declaration of authenticity of the submitted documents. 

When you have all these documents ready, book an appointment in the nearby German consulate or embassy through VFS Global according to the area of jurisdiction.  Present your documents there during Visa interview, answer few simple questions and you should get the mail for visa stamping within few weeks.

SUB-CHAPTER 2.1: WHAT TO DO WHEN YOU DO NO GET A VISA INTERVIEW APPOINTMENT IN TIME?

I have seen many students struggle to get a visa interview appointment slot in the German consulate of their of area of jurisdiction.  This is because of the high number of students applying for the interview slot. But what can be done in this situation?

A straight forward answer would be you hope that some one cancels their appointment and you are lucky enough to be first on the waiting list. However that is highly improbable. 

A more twisted but effective way can be by applying for a Visa interview in a consulate outside of the jurisdiction area of your stay. For example even though you stay in Mumbai or Bangalore, you can get a Visa appointment in German Embassy Delhi. Some consulates have more appointment slots as compared to others. 

It's possible I tell you! You just need to handle the situation smartly ;-)

SUB-CHAPTER 2.2: WHAT TO DO YOU IF YOU HAVE THE VISA INTERVIEW BUT STILL WAITING FOR THE BLOCKED ACCOUNT LETTER?

I suffered from this problem during my application process. I had the Visa interview in Mumbai consulate with all the documents ready except the blocked account confirmation letter from Deutsche bank Germany branch. I had the proof of transaction that the money has left from my Deutsche bank Indian branch few weeks ago. But still the Hamburg branch did not send me the confirmation that my blocked a/c has 8000 euros in it. I thought they will understand the situation.  But guess what, I was not even allowed to give my Visa interview! Mumbai consulate is very tough in that regard.

I tried getting another appointment but there were no available dates in Mumbai consulate anymore. So as a desperate measure, I called the German embassy in Delhi and asked for any available dates and luckily they had a few. I went to Delhi next time and process was very smooth. They even give time to submit the blocked a/c confirmation letter later. So in case you do not have a blocked a/c confirmation letter try to book an appointment in Delhi.

That's all folks! I think I have covered all the important points necessary to get a study visa for Germany. However, this process is dynamic and keeps changing. So you will have to update yourself with the exact amount necessary for Blocked a/c and demand draft. Also, if you have any suggestions, feedback or further questions you can leave a comment. 

Cheers!

*Blocked account: A blocked a/c is a student a/c where you put approx. 8000 euros for the whole year as a guarantee that you have sufficient funds, and you can take out only limited amount (approx. 750 euros) per month. Blocked a/c is only valid for the first year, i.e., the a/c becomes free in the second year of your studies and then there is no limit.

P.S.: I will continue this series-Life in Germany-with the next chapter explaining things that are important when you move to Germany as a student and few tips to handle the courses and exams in the university.

Life in Germany- Getting admission letter from a German University

Hey guys,

I see so many of our student friends thinking to carry their studies abroad. I was one of you 3 years back. I came here in September 2014 to do my masters in Chemical Engineering at TUHH Hamburg. I have successfully completed my M.Sc. and currently pursuing PhD at IMEC Belgium.

The point of this blog series-Life in Germany-is to try and explain the procedure of landing a Masters program in one of the German University and getting the Visa to Germany once you have the admission letter.

Also, I would like to add that if you are in doubt (as I was) about coming here for your studies, I would say just go for it. Its totally worth it!

So here goes...

Chapter 1: Landing an admission letter from a German University

First thing's first, it is very important that you know which course and university you are interested in. Do some research and find out a list of German universities that provide quality education in your field of interest (Useful website: https://www.daad.de). 

Keep this university list ready as you will need it to send your GRE scores online right after you finish the test.

Important documents required for applying to German university and general threshold scores:

1) 12th grade sheet (80 percent and above)

2) Transcripts of your Bachelor studies (CGPA - 8.0 and above)

3) TOEFL or IELTS (90 and above for TOEFL and 7.5 and above for IELTS)

4) Good Statement of Purpose (SOP) or cover letter (very important; 1 page max)

5) Clear and concise CV or resume (very important; 2 pages max)

6) GRE* (300 and above; not mandatory but adds weight to your application; highly recommended)

*GRE scores are to be sent directly to the German university right after the test, So you need to know which university you are interested in. You can send scores to up to 4 universities for free. For additional universities after that you have to pay an additional fees of approx 30$.

Next, Go to the online admission portal of your selected institute and upload the required documents (except GRE). Do this process quite some time before the deadline to be on the safer side. You will also have to send the original copy of Bachelor transcripts via post to that university. Once all the documents are received by the university, you will either get a mail from their office or your online application status will change to "processing" in their portal. Finally, if you are accepted, you will get an admission letter from their admissions office through post and by email. You can then start your Visa procedure (explained in the next chapter).

P.S.: In my case, I did my B.Tech from Industrial Biotechnology, had a CGPA of 8.8/10, TOEFL score of 110/120 and GRE score of 310/340. I applied for an integrated PhD course at Max Planck (highly ambitious) and got rejected in the first round. Then applied for the master course in Chemical and Bioprocess Engineering at TUHH (through their online admission portal) and got the admission letter for Winter semester 2014 within 2 months of applying.

P.P.S:  My course was an international course with all the lectures and teaching materials provided in English. There are various international courses that do not require a knowledge of German language which you can apply for. However, if you apply for a normal master course (in German language) you need to also present a German language proficiency level B1 certificate from an authorized German teaching institute (Example: Goethe institute) before you can apply for visa. 

A shallow world

She lived in a shallow world

short of hope and happiness

unaware of the things she had missed 

for all the things she desired

All she wanted was love 

and someone to express it

she found many in dreams

but none in wicked real

For real love was long lost

in this forsaken world

where pretense was a way of life

and falseness too common

All the years of shallowness

ringing into her ears

and now she lay in her deathbed

her soul full of tears

~©AR~