Operation of NX2 dense plasma focus device with argon filling as a possible radiation source for micro-machining

Dense plasma focus (DPF) can be a powerful source of X-rays at the wavelengths useful for microlithography and micromachining depending on its working gas (Ne or Ar correspondingly) and operating parameters of the device. Experimental investigations were carried out with ∼0.4-nm wavelength radiation from a specially designed medium-power soft X-ray tube with a water-cooled silver anode and highly sensitive chemically amplified resist SU-8. They have shown us that it is possible to produce 10-μm structures replicated in 100-μm resist layer and 4-μm structures produced in a 35-μm resist layer for 30 min. To decrease the time, a DPF device must be implemented for the task. Using pure argon and mixtures of argon with deuterium or krypton, we have found regimes ("hot spots," plasma pinching, and plasma compression by a "heavy shell") with appreciable soft X-ray yield. Influence on the results of chamber-circuit matching, pinch dynamics, and electron runaway processes are also discussed.