Frontend describes the process flow during which product requirements are patterned into and onto a wafer by creating different electrically active layers on each chip.
The mask set determines the patterns and can contain 10 to 50 individual masks, depending on the complexity of the chip. Per mask about 25 process steps are required.
The wafer is coated with light-sensitive chemical "resist" and exposed to light through a mask. After development, the "resist" maps the circuit design to the wafer in a process known as photolithography.
Now the desired parts are covered by the resist, while the rest can be removed by etching or treated by applying several dopants to the material.
Once the first layer is finished, the next layer of material is deposited and the process is repeated until multiple stacked layers build the complete functional chip design.
Finally, each chip on the wafer is tested before it is shipped to backend. Wafer level testing can be performed in backend as well.
The number of frontend steps can easily exceed 1,000.
At Infineon, we're pioneering Industry 4.0 standards with high levels of automation and worldwide self-optimizing work flows. Infineon Dresden is, for example, one of the most modern frontend semiconductor factories in the world.