Steuerbare Ionenquellen

Different technologies require specially adapted ion beam density profiles. Taken this into account, three different methods for ion beam profile control are investigated in combination with a ECR plasma excitation. Other plasma excitation principles like rf and dc plasma excitation are usable too together with the grid modification methods for broad ion beam profile adaptation described now:

Electrical beam profile control

The 1D electrical beam profile control of a linear ECR- ion beam source by a segmented accelerator grid (30 segments on 600mm) and a 30 times beam switch on the basis of a pulse length modulation for switching this segments between positive (blocking) and negative (accelerating) potentials could be successful demonstrated.

Ion current density distribution modified by electrical beam profile control by variation of the grid voltage pulse length modulation: best beam profile homogeneity(left), sharp peak profile(middle) and ripple profile (right), at 200mm distance

Grid geometry method

Second, an ion beam profile control by changing the geometry of the grid hole diameters together with the transparency of the whole grid system is shown on measured profile density plots, the so called zone grid method. In this example 7 zones are arranged.

Grid system with homogenous divergence angle by hole diameter and transparency variation

Beam profile control by clustering

The principle of clustering ion beam sources with 120 mm ion beam diameter is the third investigated method for ion beam profile control. Using 7 sources with special grid systems in the cluster an ion beam of 400 mm in diameter could be produced with homogeneity of less then ± 5 %. On the other hand a high dense ion beam of about 25 mA/cm2 can be produced by the alignment of 7 sources with focussed grid systems, whereby the focus of each ion beam is located in the same position approximately 300 mm in distance from the decelerator grid of the centre source.

Cluster ion beam source mounted to the vacuum chamber door consisting of 7 single sources with 120 mm ion beam diameter

Ausgewählte Publikationen zu diesem Forschungs- und Entwicklungsschwerpunkt

J. Dienelt, H. Neumann, M. Kramer, F. Scholze, B. Rauschenbach, M. Nestler, A. Tarraf, M. Schulze, A new mask blank deposition tool, Microelectronic Engineering 83 (2006) 718-722.
F. Scholze, H. Neumann, M. Tartz, J. Dienelt, H. Schlemm, Ion current density profile control of a scalable linear ion source and its application, Rev. Sci. Instrum. 77 (2006) 03C107 .
Klasse G 21 K, Patent-Nr.: 002 508.8-54: Steuerung und Regelung des Ionenstrahlprofils von Breitstrahlionenquellen durch getaktete Beamletsteuerung

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