Ion Projector Research Articles

Newly developed novolak-based resist materials for ion projection lithography (IPL) with structure dimensions of 200-100 nanometers

The application of IPL for the fabrication of nanometerstructures requires the development of special resist materials, or, at least, of novel resist development procedures. Not long ago, resist producers held the opinion that novolak-based materials are not useful for structuring in dimensions smaller than 0.3 μm. In cooperation with a well known resist company we succeeded in developing new organic novolak-based resists, which can be structured in lines and spaces smaller than 150 nm by exposure with light ions. IPL experiments were performed with the “Alpha Ion Projector” built by the Viennese company Ion Microfabrication Systems (IMS).

Distortion evaluation of nickel stencil masks with the help of ion proximity exposures and registration measurements on the Leitz LMS- 2000

A metrology has been developed to evaluate the distortion of large area stencil masks under ion beam exposure. In an ion projector an ion beam proximity printing was performed with a 85 mm diameter beam of 7.5 keV Helium ions. The gap between Nickel stencil test mask and silicon wafer was 2 mm. Ion beam exposure was done into the surface of 0.8 μm thick AZ-5206 resist with subsequent UV blanket exposure and image reversal development. The Leitz LMS-2000 registration measurement system provided data of the resist pattern to analyse the stencil mask distortion within 25 nm precision and 50 nm accuracy.

Ion projector wafer exposure results at 5× ion-optical reduction obtained with nickel and silicon stencil masks

A detailed study of the resolution performance of an advanced research type ‘‘Alpha Ion Projector’’ with 5× ion-optical reduction has been performed. One part of the study was done with a nickel open stencil test mask with an active field of 40 mm×40 mm with smallest line pattern openings of ≊0.7 μm width (2.0 μm periodicity). The other part was done with a silicon stencil test mask (120 mm diam, 2.5 μm thickness, 60 mm×60 mm design field) with smallest line patterns of ≊0.4 μm width (1.0 μm periodicity). The Alpha Ion Projector exposures were performed in positive (PMMA: OEBR-1000) and negative (SNR-M4, RAY-PN) resist materials with subsequent wet chemical development. The 0.15-μm resolution was obtained in the case of wafer exposures with the nickel stencil mask within the 8 mm×8 mm exposure field whereas in the case of wafer exposures with the silicon stencil mask sub-0.1-μm resolution could be achieved near the center of the exposure field at 5.2× ion-optical reduction.

In situ distortion measurement of an ion projector with 5× ion-optical reduction

In situ distortion measurements of an ion projector with 5× ion-optical reduction were performed. At optimum conditions the measured minimum distortion was less than 0.15 μm within an exposure field of 8 mm×8 mm. This result is in excellent agreement with fifth order ion-optical calculations.

Desorption ion projector: V M Gavrilyuk and V K Medvedev, ( Patent), Auhtor's certificate SSSR, class 21, 37/01, /N 01, No 168815, claimed 20 Nov 1963, published 10 March 1965, ( Russian).

Desorption ion projector: V M Gavrilyuk and V K Medvedev, ( Patent), Auhtor's certificate SSSR, class 21, 37/01, /N 01, No 168815, claimed 20 Nov 1963, published 10 March 1965, ( Russian).