Etching process results in creation of chips after selectively removing films and materials that are deposited on the wafer. Strip and clean techniques are used between manufacturing steps to eliminate unwanted material that could later lead to defects and to prepare the wafer surface for subsequent processing. The vacuum requirement for stripping and cleaning process is in the range of 1 mbar and high capacity dry pumps are most suited. Due to the absence of load lock chambers in the some equipment used in this process, faster pump down times are expected for high throughput
Processes like Dry dielectric etching, Conductor and Polysilicon etching operate in the range of 0.01 to 0.001 mbar and combinations of turbopumps backed by dry vacuum pumps are mostly suited for this process. Turbopumps are connected to the chamber while dry backing pumps are placed in the basement.
Advanced etch techniques, such as atomic layer etching (ALE) are capable of removing a few atomic layers of material at a time. While conductor etch processes precisely shape electrically active components like transistors, dielectric etch forms the insulating structures that protect conducting parts.
Implantation of Ion
A major consideration in chip manufacturing is changing the electrical characteristics of the material and improving the conductivity of the device. As a result, doping the silicon wafer surface with ions is of vital importance. The main areas where significant contribution of vacuum pumps is observed are: Beamline, End station and Ion source.
Ion source operation consists of a combination of turbo pump with dry vacuum pump. For the dry vacuum pump, leak check is mandatory as this will impact the process lifetime. Further process grade N2 purge is mandatory for the operation.
For the beamline area and end station area, turbopumps can be used for providing absolute clean environment at vacuum range of 10⁻⁸ mbar.
