The implantation chamber is a standard high-voltage-engineering-chamber.
The original vacuum system has been replaced, instead an NW 200 ISO vacuum cross has been installed at the entrance of the chamber, which is equipped with a cryopump with 1500 l/s and a scroll pump with 30 m³/h. This combination pumps the chamber about six orders of magnitude in five minutes.
The former computer unit used for dose measurements has been replaced by a Corner-Cup system. In addition, the original drive motor and the positioning system have been replaced. For this purpose, an optical unit was installed in a vacuum together with a stepper motor on the outside of the chamber.
In order to process wafers with different diameters, this end station is used for manual assembly. Wafer Handling Sets for 75, 100, 125, 150 and 200mm wafers are available (The maximum illuminated area on this unit is limited to 150mm). The flexible use of inlets in these sets also allows the inclusion of wafers with unconventional dimensions.
An interchangeable dose measurement system has been developed for implantation of power devices requiring relatively high doses (> 10 E14 cm-2) and high particle energies (C12 to 25 MeV). The dose measuring system consists of a jet-defining opening of 15 mm diameter and a swinging Faraday cup behind it. The charge accumulated on the wire is used for dose measurement. The implantation was only necessary in a small ring around the center. Special tantalum masks were made. The implanted spot was kept as small as possible to keep neutron production at a low level and save implantation time. Calibration standards have been established for various ions, energies and charge states.
Clean room HVEC
The entire implantation cycle is performed computer-aided, fully automatic according to a customer-oriented recipe.
The placement of the Waferdisc's is done manually by the surgeon depending on the product to be implanted. After loading the disc, the chamber is closed and automatically evacuated. The measuring ranges of the can controller dc 401 from the company tribotec-electronic GmbH are automatically adjusted.
After reaching the parameters in the recipe, the implantation is started fully automatically. After implantation, the chamber is returned to atmospheric pressure via the automatic flooding. The finished implanted wafers are removed by the technician. The cycle can start new.
The implantation system consists of an electrostatic beam scanning system, diagnostic device and an implantation chamber. The beam grid system generates high linearity triangular voltages, driving the two sets of plates for horizontal and vertical beam scanning.
A diagnostic device is used to center the ungraded ion beam and the dose measurement during implantation. A mask determines the size of the irradiated area on the sample. Around the mask, small measuring orifices are arranged behind the Corner-Cups are mounted. The same currents in the corner cups mean a homogeneous deflection.
During implantation, the dose is measured via one of these cups.