Contact and proximity lithography using 193 nm Excimer laser in Mask Aligner

In this paper we describe the use of an Excimer laser for full-field lithography in a Mask Aligner. The DUV light from the Excimer laser is homogenized by using micro lens based optical integrators instead of a macro lens array. A simulation of the intensity distribution for 5 μm squares was performed to visualize the diffraction effects and to show the potential of 193 nm illumination. It is demonstrated that compared to the conventional homogenization optics the MO Exposure Optics further improves the illumination uniformity, calculated as 1.8% for MO Exposure Optics and 2.9% for the A-Optics. Moreover the improved optical setup allows a modification of the angular spectrum by using exchangeable illumination filter plates (IFP). Compared to the A-Optics the main improvement effect of MO Exposure Optics is detectable in the patterning of layouts containing critical dimension from 8 μm down to 2 μm.     

Full wafer microlens replication by UV imprint lithography

The fabrication of microlenses is of great interest for several applications in the field of optics like wafer level cameras, homogenization of light, and coupling of light into glass fibers. Especially for low-cost optical products, microlenses have to be fabricated with a high throughput at an adequate quality. One way to fulfil these requirements is the patterning of microlenses by UV imprint lithography (UV-IL). Within this work, microlenses were replicated into the UV curing material PAK-01 by step and stamp UV-IL on silicon substrates with a diameter of 150 mm. The resulting substrates were used as masters to cast PDMS templates. These PDMS templates can be used for high throughput full wafer UV-IL. Additionally, quartz substrates with a diameter of 100 mm were patterned which could be directly used as so called “optowafers”. Master and patterned microlenses were inspected by scanning electron microscopy and with a white light profilometer. The results clearly demonstrate the excellent quality of the replication process and the capability of UV-IL to pattern microlenses on full wafer level for high throughput applications.     

7.4 Gbit monolithically integrated GaAs/AlGaAs laser diode-laser driver structure

A molecular beam epitaxy (MBE) grown GaAs/AlGaAs multiquantum well laser, monolithically integrated with a laser driver was realised on 2 inch GaAs substrate wafers. In an optical data communication set up, performance up to data rates of 7.4 Gbit/s was demonstrated.<>     

Temperature desensitisation of delay in optical fibres for sensor applications

We demonstrate a significant reduction in delay sensitivity against temperature in optical fibres, using a novel tight jacketed fibre structure. This technique has the cabability of producing fibre in which the optical delay is insensitive to temperature. This has potential in the field of sensors and fibre devices.     

Study on the reliability of an InP/InGaAsP integrated laser modulator

Ridge Integrated Laser Modulator (ILM) devices were fabricated using a butt-coupling technology based on two gas source molecular beam epitaxy. A complete stability evaluation was undertaken, including a reliability study on discrete lasers, discrete modulators and integrated devices. The butt-coupling integration process does not affect the reliability of the integrated devices.     

LED spectral slicing for single-mode local loop applications

An approach towards a single-mode local loop is presented in which each customer is given a dedicated wavelength channel by taking different wavelength slices from identical LEDs. This is accomplished by means of wavelength division multiplexing (WDM) components. Results from a four-channel system operating at 2 Mbit/s over 2.2 km, together with a theoretical analysis of a ten-channel system, are presented     

Two beam surface fluctuation specular reflection spectroscopy

In surface fluctuation specular reflection spectroscopy (SFSRS) deflections of a specularly reflected laser beam are used to characterize thermally excited surface waves. Here we report on a new two beam version of SFSRS in which the deflections of two reflected laser beams from separate locations on a surface are correlated. We demonstrate that this new two beam SFSRS technique can be used to determine directly the power spectrum of height fluctuation of thermally excited surface waves over a large range of both frequencies and wavevectors. In addition, we show that the technique is well suited for materials ranging from simple liquids to complex liquids and soft solids, including turbid materials.     

Smart Scribbles for Sketch Segmentation

We present ‘Smart Scribbles’—a new scribble‐based interface for user‐guided segmentation of digital sketchy drawings. In contrast to previous approaches based on simple selection strategies, Smart Scribbles exploits richer geometric and temporal information, resulting in a more intuitive segmentation interface. We introduce a novel energy minimization formulation in which both geometric and temporal information from digital input devices is used to define stroke‐to‐stroke and scribble‐to‐stroke relationships. Although the minimization of this energy is, in general, an NP‐hard problem, we use a simple heuristic that leads to a good approximation and permits an interactive system able to produce accurate labellings even for cluttered sketchy drawings. We demonstrate the power of our technique in several practical scenarios such as sketch editing, as‐rigid‐as‐possible deformation and registration, and on‐the‐fly labelling based on pre‐classified guidelines.