On our website you will find information about our organization, a brief overview of our project as well as our main deliverables to our sponsor. For a more detailed look at our project, please refer to the final report document under the deliverables section.
Cluster tools are systems used in the semiconductor processing industry to fabricate microelectronic devices and components. One of the advantages of cluster tools is that they can perform processes in sequences to improve product yield. Furthermore, they reduce contamination, which is very important in the processing of semiconductors. All semiconductor processes depend on these tools to process wafers in their respective areas.
One cluster tool in particular, known as an implant tool, was the object of interest for our current project. Implant tools are composed of several hardware components with the main internal component being an ion source. The ion source is composed of two main parts: a cathode and a filament. The filament heats up the cathode, which in turn interacts with the gas flow; thus, creating a plasma. The plasma is then guided through magnets, acting as ion filters, and is then accelerated to implant the filtered ions onto the surface of the wafers.
In the implant process, wafers are bombarded with ions from different elements - called dopants - such as, Boron (B), Phosphorous (P), Arsenic (As), Carbon (C), and Germanium (Ge) into and on top of a wafer in order to modify its conductivity. The specific format used to implant these elements is known as the implantation recipe. The recipe contains information, such as the amounts of gases, pressure, temperature, and current needed for the implantation process.
The implantation recipe is critical in helping to optimize the throughput of implant tools, which is an activity of great interest today with the continuously decreasing size of semiconductors. One method in particular that is used to improve product yield is Recipe Sequencing. This method can reduce the tool preparation time between different implantation recipes by organizing the recipes in sequences, where the wafer batches are scheduled to be processed depending on the implantation recipe they require, instead of on a first come, first serve basis.