In the following text I will give a little explanation about my masterthesis
The title of my masterthesis is ‘Safety issues of III/V processing in microchip manufacturing’. I do this in cooperation with Imec which is situated in Heverlee, Belgium.
My primary supervisor is the head of security of Imec , and actually I work for him. I also stay in close contact with the engineers and a group of scientists that work on this project.
The project didn’t started a long time ago so the work I am going to do can be very crucial for the development of those safety issues which makes it much more interesting for me and it is a bigger challenge because it’s a starting branch of a big and successful company.
In a first stage I have to understand how a microchip is fabricated and how it works. All the steps have to be clear. I also have to understand the techniques that are used to fabricate a microchip.
After this step I had to give a presentation at Imec in front of the head of security and it went great.
Now I am walking in to the second phase which is the understanding of all the chemical reactions of III/V processing and the safety hazards that come with them.
After this brief introduction I am going to discuss the biggest difference between the normal way of fabricating a microchip and III/V processing.
In normal IC development the different layers of the microchip are put on each other. For example we start with a p-doped Silicium (IV) substrate and we start to put other materials on top of this to for example form a pn- and np-junction or to protect the layer beneath (this is done by SiN, TiSi2)… After almost every step that a new layer is composed there has to be an ‘etching-‘or ‘masking’-step. In these steps a part of the layer is removed to form a connection hole or to be filled up with another material. These etching steps are crucial and critical steps because they are often performed by a chemical reaction. Due to this chemical reaction gasses can be formed that can give safety hazards.
In III/V processing the microchip is formed out of components of the third and fifth column of the table of Mendeljev. The base of the microchip is already formed. We don’t work from top to bottom by putting layers on top of each other. A question that may rise is: How do you form the connection holes? And how can the microchip are provided of the necessary material? This is done by penetrating the microchip from the top to the desired layer. This is again done by different etching steps. These etching steps are different from those used in the normal IC manufacturing.
My key purpose is to discover the chemical reaction that occur in these etch-steps and try to find alternatives of solutions to ensure the safety of the employees at Imec. The final goal is to elaborate a risk-analysis. This is not only done by me but in cooperation with the head of security and the engineers.