On Thursday, January 10, 2016, Peter Mader, graduate of our university and former chairman and founding member of the IEEE STudent Branch Passau, talked about the production of silicon wafers and the challenges they pose for his company Siltronic.
The company, who was formerly part of Wacker-Chemie, has existed for almost 50 years. During this period, Siltronic, as the only company in the Western world, became the 4th largest wafer manufacturer. The silicon wafers are produced at several locations around the world, including Burghausen, Portland and Singapore.
What are silicon wafers? This refers to thin slices of high-purity silicon, from which micro-chips are produced. While demand came from the computing segment about 20 years ago, the demand is much more widespread today and also includes the areas of communications, industry, cars, as well as IoT and direct consumer products. Thus, for the production of a Tesla a wafer with a diameter of 200mm and for a modern electric locomotive about 20 of these wafers needed.
How exactly is such a wafer produced? The first step in the manufacturing process is the "pulling" of a high-purity silicon single crystal, from molten raw material. This is then sliced in the following and obtaines by several cleaning, as well as laser or chemical treatments its desired properties. While the wafers currently support a thickness of 8nm and a maximum of 32 levels on top of each other, customers are already demanding 128 levels, and the minimum thickness should also be reduced to 5nm in a few years.
Depending on the wafer size the manufacturing process consists of about 45 to 70 individual steps for which again up to 6000 parameters are needed to obtain the desired results. In order to remain competitive in this complex process, a very good automation is needed, with the aim of obtaining a "black light factory" in a few years, in which one can simply switch off the light, and all work goes on as normal. At Siltronic, this plan is implemented by means of a central ERP system as well as the for production important IT infrastructure which is available at all sites.
Currently a big project, is the transport automation, where as two different systems are already in use. On the one hand there is the variant that smaller vehicles drive on rails over the machines and transport the containers with wafers. The other variant are larger vehicles traveling on the ground, which can transport more containers at the same time. Challenges in this project are the high accuracy with which the containers must be loaded into the machines and the often strict time constraints. In addition, the actual implementation is not as easy as many would think, since really all processes need to be standardized. You can not just say to a machine, "You knock once against it and then it works again."
Advantages of automation are not only the lower costs, but also a lower workload for the employes, since via data glasses, suppport can also be provided from outside the production areas and thus the time-consuming process of entering the clean rooms is eliminated.
All in all, the lecture was a very detailed insight into an industry that we are not so aware of, as we end up with only the processed products in our hands and little notice of the ingredients.