Maarten Marinus Johannes Wilhelmus Van Herpen

Grid spectral purity filters for suppression of infrared radiation in laser-produced plasma EUV sources

We have developed a grid-type spectral purity filter (SPF) for suppression of infrared radiation in laser-produced plasma (LPP) EUV sources for high-volume EUV lithography. The SPF is a silicon grid with sub-wavelength periodicity that is metalized to make it reflective for infrared radiation. EUV radiation is transmitted geometrically through the open area of the grid. The first prototype samples show an in-band EUV transmittance of 74% at normal incidence. Infrared spectrometry exhibits a clear cut-off behavior as expected, with a transmittance of <0.1% at a wavelength of 10.6 µm. In a first power-load test, a grid was exposed to a CO2 laser at 100 W/cm2 in vacuum for 8 hours. Another grid was kept at 800 °C in a vacuum oven for 24 hours. Both grids remained structurally intact and maintained an infrared transmittance of <0.1%.

Is exhaled carbon monoxide level associated with blood glucose level? A comparison of two breath analyzing methods

The level of exhaled carbon monoxide (eCO) is considered a marker of oxidative stress in diabetes. Previous findings indicated that eCO levels correlated with blood glucose level. The aim of this work was to apply and compare two independent analyzing methods for eCO after oral glucose administration. Glycemia, eCO, and exhaled hydrogen were measured before and after oral administration of glucose. Six healthy nonsmoking volunteers participated. For eCO analysis, we used two methods: a commercially available electrochemical sensor, and a high-precision laser spectrometer developed in our laboratory. The precision of laser-spectroscopic eCO measurements was two orders of magnitude better than the precision of the electrochemical eCO measurement. eCO levels measured by laser spectrometry after glucose administration showed a decrease of 4.1%+/-1.5% compared to the baseline (p<0.05). Changes in the eCO measured by the electrochemical sensor were not significant (p=0.08). Exhaled hydrogen levels increased by 40% within the first 10 min after glucose administration (p<0.05). The previous finding that the glycemia increase after glucose administration was associated with a significant increase in eCO concentrations was not confirmed. We propose that previous eCO measurements with electrochemical sensors may have been affected by cross sensitivity to hydrogen.

Atomic-hydrogen cleaning of Sn from Mo/Si and DLC/Si extreme ultraviolet multilayer mirrors

We have investigated the use of atomic-hydrogen-based cleaning to remove Sn contamination from extreme ultraviolet (EUV) multilayer mirrors. Mo and Si surfaces were cleaned at a relatively slow rate due to catalyzed dissociation of tin hydride on these surfaces. Mo/Si mirrors with B4C and Si3N4 cap layers and DLC-terminated DLC/Si mirrors showed complete removal of 10 nm Sn in 20 sec with full restoration of EUV reflectance. In addition, a prolonged cleaning treatment of 300 sec of a DLC/Si mirror resulted in only a minor EUV peak reflection loss of 1.2% absolute and no significant changes in infrared reflectance.

A novel nano-photonics biosensor concept for rapid molecular diagnostics

We present a novel nano-photonics biosensor concept that offers an ultra-high surface specificity and excellent suppression of background signals due to the sample fluid on top of the biosensor. In our contribution, we will briefly discuss the operation principle and fabrication of the biosensor, followed by a more detailed discussion on the experimentally determined performance parameters. Recent results on detection of fluorescently labeled molecules in a highly fluorescent background will be shown, and we will give an outlook on real-time detection of bio-molecules such as proteins and nucleic acids.

Debris mitigation for EUV sources using directional gas flows

Practical EUV sources not only generate the desired EUV radiation at a wavelength of 13.5 nm but also produce debris that severely limits the lifetime of the collecting optics in the lithographic system. In this paper, we address the possibility of reducing the exposure of the collecting optics to debris by using directional gas flows, focusing particularly on mitigation of ballistic microparticles. The purpose of the gas flow is to change the direction of the particles such that they can subsequently be captured by a foil trap. Two types of gas flows are considered: (i) longitudinal gas flows, i.e. with a flow direction essentially parallel to the velocity of the microparticles, and (ii) transversal gas flows, having a flow direction essentially perpendicular to that of the microparticles. We have conducted contamination experiments using both types of flows in Xe- and Sn-based experimental EUV sources with Ar gas. The experiments show that directional gas flows suppress microparticles in the same way a buffer gas does unless the flow velocity becomes of the same order as the thermal velocity of the gas (~ 102 m/s). A high-speed longitudinal gas flow is expected to be more efficient in thermalizing the microparticles than a stationary buffer gas; this could however not be confirmed due to experimental constraints. Our experiments with a high-speed transversal gas flow show that submicron debris particles can successfully be suppressed by one order of magnitude. A transversal gas flow combined with a suitable foil trap structure may thus present an effective method for mitigation of microparticles.

Tuberculosis prevention must integrate technological and basic care innovation

Albert et al. [1] advocate for a multipronged approach in rolling out new diagnostic technology for tuberculosis (TB), stating “diagnostic tests alone, if not implemented with a comprehensive package of accompanying tools and within the context of a strengthened health system, may fail to demonstrate the expected benefit”. This is a lesson learned from those who have walked this path before us; one should not be too complacent to ignore basic strategies in the face of escalating technological advances in our field. Without societal, lifestyle and dietary innovations, new technologies will be ineffectual in stopping tuberculosis http://ow.ly/IgY3303bgdU