As I summarized in my previous post, on the 1st week of May I was struggling with my wafer bonding experiment. Yep, currently my research is focused on wafer bonding. As I also mentioned previously, I will discuss about this wafer bonding scientifically in later post. Therefore, long story short this wafer bonding, as explained in Q.-Y. Tong's book, is the experiment conducted by "simply" bringing two different wafers into contact and sticking them directly to each other by the help of either van der Walls force, capillary force or electrostatic force.
Why I quoted the simply term above? Because the basic concept is simple, just bringing them into contact. However, the most important prerequisite prior to contact is the surface of the wafer should be flat, clean and smooth enough, and this ain't an easy jobs. The wafers need to be cleaned by using some series of physical and chemical cleaning process which is not quite simple and sometimes a little bit dangerous, thus it needs to be handled with extra care.
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| SEM images of the cross section of my successful wafer bonding experiment result |
Let's look the SEM picture of the bonded wafer's cross section above. Now imagine, what happened if there is dust at the bonding interface? Yes, the surface will not 100% touch each other. Since this is a microscale experiment, the non-existence of dust is really important to promote better surface interaction. After sticking them together, it needs one final step which is a annealing process to strengthen the bond between the wafer. In the first time, I performed this annealing in other lab by the help of my friend.
However, due to the close deadline of the lab meeting (5/4) and the availability of my friend and his machine, I only had a chance to perform the annealing experiment either on Thursday (5/2) or Friday (May 3) evening. It made me confused at that time, since I already planned to attend KAIST-ONE Brazil on Thursday evening coincidentally at the similar time proposed by my friend to do the annealing experiment, and on Friday I aimed to prepare my Saturday lab meeting. These difficult choices needed to be decided immediately.
*When you are facing some difficult choices in your life, don't simply give up. Because your life is actually composed of the choices (C) you make between the day of your birth (B) and death (D). This B-C-D phenomenon will be further discussed in my later post regarding my life on the 2nd week of May 2013, which is attending 6th TEDxKAIST.
Finally, I made my decision. I canceled my plan to attend KAIST-ONE Brazil and did the annealing experiment instead. This choice I considered as one of my good decisions. After annealing, I observed that my experiment was success as you can see in the SEM images above. This long time trial and error experiment turned into first time success. Using this result I prepared my lab meeting presentation on Friday and fortunately the responses from the audiences were mainly positive. FYI, in the grad student life lab meeting is one regular meeting where you present the result of the researches you have been conducting during a certain period of time (honestly for me, it is in principle the period between each of my lab meeting turn). In my perspective, this meeting is really important because the discussion happened during lab meeting can enrich your knowledge and sometimes when you're facing some problems in your research, through the discussion, other lab mates or professor may give some suggestion that may help you to solve your problem. Thus, good preparation for lab meeting is required in order to communicate the result of your researches better.
At last, the disappointment of not attending the KAIST-ONE Brazil was totally gone after completing my lab meeting on that Saturday and gaining some positive feedback to my research. Usually, my habit after completing a lab meeting is relaxing my mind after hard preparation of lab meeting. On that week I chose to have some rest and woke up late on Sunday. After waking up I had some brunch with simultaneously watched Safe Haven, adapted from one of Nicholas Sparks romance novels, in my laptop. Watching some movie or TV series is one of my way of relaxing my mind. In the afternoon I decided to have my Sunday afternoon walk. I fully charged my iPhone battery and then went to the Gap Stream (갑천) in front of my campus. I walked along the stream while listening to my mixed albums of Maksim & Bond played by my iPhone. I headed to the east where I finally arrived at Hanbat Arboretum (한밭수목원) after 30 minutes of walking.
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| Some pictures taken at Hanbat Arboretum (한밭수목원) East Arboretum | |||
This arboretum is really big. It has two arboretum wings and huge central plaza in between of these arboretums. At this central plaza many events have been held, i.e. Easter mass, cultural festival, food festival, etc. In the central plaza, you are also able to rent various kind of public bicycle and ride it to look around the plaza. But please be noticed that the bicycle can't enter the arboretum. I got caught before while entering the arboretum using my bicycle by the security in front of arboretum's gate. While I was in the arboretum, I spent most of my time in the east arboretum, sightseeing and enjoying the scenery of blossoming flowers in the blissful spring season. I captured many pictures of the flowers as you can see in my picture collection above. In the end, I totally recommend this nice place to hang out, have some picnic and spend some quality time with your family or your significant other.
So, that's the story of my life on the 1st week of May 2013.
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