Augmented and mixed reality applications have recently gained large interest. In order to fabricate lightweight near eye displays surface relief gratings are used for coupling the light from the source into the light guide and out of the light guide towards the eye. To suppress higher diffraction orders and thus maximize the light yield those gratings are slanted. In order to achieve high field of view variation of the slant angle is desirable yet rather difficult to achieve. Ion beam trimming (IBT) is a method well established in MEMS and sensor manufacturing to locally modify the thickness of a layer or substrate in order to achieve a desired target topography. This method has been adapted towards fabrication of surface relief gratings with both varying slant angle and varying trench depth. The optically transparent substrate (e.g. SiO2) had been covered with a hard mask providing the basic grating geometry such as period and duty cycle. Localized ion beam etching was then applied to etch the trenches. Varying the ion irradiation dose (by means of dwell time variation) sets the trench depth on a local level. The angle of incidence of the ion beam directly transfers into the substrate as the slant angle and can be varied independently of the dwell time providing the unique possibility to achieve a continuous variation of the slant angle across one die. To avoid redeposition of the sputtered trench material to the grating side walls the etching was carried out in the reactive ion beam etching (RIBE) regime. Furthermore the choice of the process parameters (process gas composition, ion energy) allows for tuning the selectivity between hard mask and target material such that high aspect ratio trenches are possible while keeping the hard mask thin avoiding shadowing of neighboring structural features.

A significant portion toward understanding evolution of the universe comes from x-ray astronomy since many astronomical objects of interest, such as black holes, supernovae and distant galaxies, emit radiation in the x-ray band. As basically all materials have almost unity refractive index for x-rays focusing x-ray beams is only possible by reflection at grazing incidence. Due to the low photon flux of the objects under study (few photons per hour) each individual photon is of particular interest. Thus, the collective area of x-ray telescopes needs to be as large as possible which is achieved by a large amount of concentrically nested x-ray mirrors whose shape needs to be ideal fitting to the designed geometry for high image quality. Due to the mirrors' curvature even state of the art mechanical machining and chemical mechanical polishing processes leave a residual surface error of several hundred nanometers. Those residual errors can be significantly reduced by ion beam figuring.

Ion beam technologies have become an established alternative to common mechanical polishing methods in manufacturing optics. Ion Beam Figuring (IBF) is increasingly being used for the precise figuring and finishing of optical elements, such as spheres, aspheres and free forms on lenses and mirrors. Next to the finishing of optical components, an IBF process can also be employed on the molds that are used to produce optical lenses. The mold pins that are employed in the consumer goods market usually require a fairly high financial investment. As the quality of a lens ultimately depends on the surface of the optical mold, an error correction process on the mold itself may proof a more cost effective exercise than the polishing of the lenses post-production.

Amorphous InGaZnO (α-IGZO) thin-film transistors (TFTs) are are very promising due to their potential use in thin film electronics and display drivers [1]. However, the stability of AOS-TFTs under the various stresses has been issued for the practical AOSs applications [2]. Up to now, many researchers have studied to understand the sub-gap density of states (DOS) as the root cause of instability [3]. Nomura et al. reported that these deep defects are located in the surface layer of the α-IGZO channel [4]. Also, Kim et al. reported that the interfacial traps can be affected by different RF-power during RF magnetron sputtering process [5]. It is well known that these trap states can influence on the performances and stabilities of α-IGZO TFTs. Nevertheless, it has not been reported how these defect states are created during conventional RF magnetron sputtering. In general, during conventional RF magnetron sputtering process, negative oxygen ions (NOI) can be generated by electron attachment in oxygen atom near target surface and accelerated up to few hundreds eV by self-bias of RF magnetron sputter; the high energy bombardment of NOIs generates bulk defects in oxide thin films [6-10] and can change the defect states of α-IGZO thin film. In this paper, we have confirmed that the NOIs accelerated by the self-bias were one of the dominant causes of instability in α-IGZO TFTs when the channel layer was deposited by conventional RF magnetron sputtering system. Finally, we will introduce our novel technology named as Magnetic Field Shielded Sputtering (MFSS) process [9-10] to eliminate the NOI bombardment effects and present how much to be improved the instability of α-IGZO TFTs by this new deposition method.

AbstractDie steigenden Anforderungen an die Polierfehlerkorrektur in der Optikindustrie führen zur Entwicklung von innovativen Anlagenkonzepten, die den hohen Standards gerecht werden und gleichzeitig effektive Durchsatzraten gewährleisten.Die Autoren dieses Artikels präsentieren ein fortschrittliches neues Anlagensystem für den kommerziellen Optikmarkt, welches anlagentechnische Neuerungen mit einem ausgefeilten Prozessfluss verbindet. Einsparungen von unnötigen mechanischen Komponenten, der Einsatz einer Doppelschleuse und ein modifizierbarer Strahldurchmesser führen zu einer Bearbeitungsgenauigkeit besser als λ/50. Das Anlagensystem eignet sich für diverse Materialien in der Herstellung von optischen Bauteilen mit sphärischen und asphärischen Konturen sowie jeglichen Freiformflächen und ist mit einer eigens dafür entwickelten Software ausgestattet. [1]

Silicon lenses are widely used for infrared applications. Especially for portable devices the size and weight of the optical system are very important factors. The use of aspherical silicon lenses instead of spherical silicon lenses results in a significant reduction of weight and size.The manufacture of silicon lenses is more challenging than the manufacture of standard glass lenses. Typically conventional methods like diamond turning, grinding and polishing are used. However, due to the high hardness of silicon, diamond turning is very difficult and requires a lot of experience. To achieve surfaces of a high quality a polishing step is mandatory within the manufacturing process. Nevertheless, the required surface form accuracy cannot be achieved through the use of conventional polishing methods because of the unpredictable behavior of the polishing tools, which leads to an unstable removal rate.To overcome these disadvantages a method called Ion Beam Figuring can be used to manufacture silicon lenses with high surface form accuracies. The general advantage of the Ion Beam Figuring technology is a contactless polishing process without any aging effects of the tool. Due to this an excellent stability of the removal rate without any mechanical surface damage is achieved. The related physical process - called sputtering - can be applied to any material and is therefore also applicable to materials of high hardness like Silicon (SiC, WC).The process is realized through the commercially available ion beam figuring system IonScan 3D. During the process, the substrate is moved in front of a focused broad ion beam. The local milling rate is controlled via a modulated velocity profile, which is calculated specifically for each surface topology in order to mill the material at the associated positions to the target geometry.The authors will present aspherical silicon lenses with very high surface form accuracies compared to conventionally manufactured lenses.

The rising quality demands in the production and refinement of optical components continuously lead to the development of innovative equipment, which meets the high standards and guarantees an efficient throughput at the same time. The authors of this article present a new process system for the commercial manufacture of optical components, combining new technology with an optimized process flow. A reduction in dispensable mechanical components as well as the use of a double load- lock and the ability to individually adjust the parameters leads to process accuracy better than lambda/50. The process system is suitable for diverse materials used in the manufacture of spheres, aspheres and free form samples and employs a specifically developed software.

Recently and upcoming optical applications depend more and more on the precision of the optical elements used. The last is especially driven by shorter wavelength, higher flux densities and imaging close to the diffraction limit. Therefore a dramatically increasing demand on high precision and high quality optical components in leading edge equipment as well as common devices and instruments is observed. So far a few methods have been introduced to provide an adequate manufacturing performance using mechanical grinding and polishing techniques. Up to now the very sophisticated ion beam figuring (IBF) has not been used for common optics. The reasons for this might be the perception of higher costs and less knowledge about the technique in the industry. Now an affordable ion beam figuring technique has been developed to address precision aspherical optics applications. This paper introduces ion beam figuring technology based on equipment which is widely used in semiconductor mass production for ultra precise film thickness trimming. Ion beam figuring works by raster-scanning a focused broad ion beam across an optical surface with variable velocity and dwell time in order to precisely and locally trim away surface contour errors. As a new and cost effective approach the ion beam figuring system used in this presentation applies a 3 axis movement system only (compared to expensive 5-axis movements in other applications). X-and y-axes are used for the areal scan, and the z-axis is used for focus adjustment due to the surface contour of the optical element. The system was intentionally designed without the 2 additional tilt axes for incident angle adjustment and cleverly reduces the complexity and size of the system. It is shown that curved spherical or aspherical surfaces can be corrected down to lambda/50 or better by using the state of the art 3-axes trimming system. Even with high spatial frequency parts final processing qualities better than lambda/10 are achieved.

The success of many advanced technologies increasingly depends on the precision of the optical lenses used. Therefore the demand for high precision optical elements in more common devices and instruments is increasing as well. Concurrently the need to make devices smaller and lighter weight is also driving the demand for precision optical elements. Therefore, the use of aspherical glass lenses is growing tremendously and has become the standard for many applications.So far most methods for manufacturing aspherical glass surfaces use grinding and polishing. Very sophisticated methods such as Ion Beam Figuring have not been used for common precision optics. The reasons for this might be perceptions of high costs, doubt about the ablation rate and limited knowledge about the technique within the optical industry.Now Asphericon has set up its first ion beam correction system for precision aspherical optics (asphericon ION-Finish). This presentation will show how the ion beam technology has matured and become affordable enough for common precision applications. In some examples we will show how ion beam systems are used to correct aspheres to precisions of better than lambda/60 rms (10nm). Together with a flexible measurement technique, the manufacturing of aspherical glass lenses becomes very fast and cost-efficient. Furthermore, advantages and disadvantages will be discussed. In connection with that the required quality of the pre-polishing will be addressed too. Finally it will be shown how fast the correction process can be and how flexibly the size of the tool can be changed.

Many applications in semiconductor technology are characterised by extreme requirements in terms of film thickness homogeneity. When manufacturing Bulk Acoustic Wave (BAW) components, it is necessary to adjust film thickness values of different materials with accuracy values in the nm-range. Standard processes, such as the film deposition techniques, do not fulfil these homogeneity requirements. Thus it is necessary to perform a local correction of the film thickness in a follow-up process.The authors here introduce a new method of local film thickness trimming and its technical implementation. During the process, the wafer is moved in front of a focussed ion beam. The local milling rate is controlled upon the residence time of the ion beam at certain positions. A modulated velocity profile is calculated specifically for each wafer, in order to mill the material at the associated positions to the homogenous target film thickness.Depending on whether an inert or reactive ion beam process is used, it is possible to apply the IonScan technology for any material desired, such as Si3N4, SiO2, Al2O3, AlN, W, Mo, Cu or NiFe.

AbstractFür verschiedene Anwendungen in der Halbleitertechnologie werden extreme Anforderungen an die Homogenität von Schichtsystemen gestellt. Bei der Herstellung von BAW‐(Bulk Acoustic Wave)‐Bauelementen müssen Schichtdicken von unterschiedlichen Materialien mit einer Genauigkeit im nm‐Bereich eingestellt werden. Mit den Standardtechniken zur Schichtabscheidung werden diese Homogenitätsforderungen nicht erfüllt, so dass in einem Folgeprozess die Schichtdicke waferspezifisch und lokal korrigiert werden muss. 1,2Wir stellen ein neuartiges Verfahren und dessen anlagentechnische Realisierung für die lokale Schichtdickenkorrektur vor. Im Prozess wird der Wafer mäanderförmig vor einem fokussierten Ionenstrahl bewegt. Spezifisch für jeden Wafer wird ein moduliertes Geschwindigkeitsprofil berechnet, um über die Verweilzeit des Ionenstrahls an den jeweiligen Positionen das Material bis auf die Zielschichtdicke abzutragen.Basierend auf einem inerten oder reaktiven Ionenstrahlprozess lässt sich das Verfahren auf beliebige Materialien anwenden, wie z. B. Si3N4, SiO2, Al2O3, AlN, W, Mo, Cu oder NiFe.

A very compact type of broad beam ion source based on transformer coupled plasma excitation (TCP) is described. Our ion source consists of a cylindrical RF coil surrounding the discharge vessel and a very compact, patented matching unit from special ceramics capacitors attached directly to the discharge arrangement. However, the TCP excitation as well as the sophisticated layout of the matching unit require an optimum source arrangement due to the beam parameters, the source lifetime and the performance of the RF elements. For that reason, a global discharge model was applied together with an RF replacement circuit diagram to calculate for the optimum source layout. An advanced plasma and beam diagnostics is used for controlling the source performance due to beam composition, beam profile and ion energy distribution. In this way, our RF source is adapted to different beam requirements in inert and reactive beam processes for etching, modification and sputter deposition.

Ion Beam Figuring (IBF) and Ion Beam Polishing (IBP) are advanced tools mature for high performance optics production. Three Partners IOM, IOT and NTGL are about to commercialize these techniques as systems solutions.

We characterise the kinetics of RF magnetron sputtering of PTFE by mass spectrometry and correlate the results with film properties. The process performance is strongly affected by the conditioning of the chamber walls causing a drift in the discharge potential conditions. Various CXFY+ fragments and compounds up to X=4 could be detected in the discharge with the origin of these species detected from structures in the energy distribution. The most important species for the film deposition seem to be the low molecular fragments (CF, CF2). Direct information about processes occurring at the sputter target could be obtained from the negative F - energy distribution

The error probability at a node of a digital circuit exposed to thermal noise agitation is investigated and the minimal dissipation–reliability relation for practical electronic circuits is derived. The digital circuit is modeled by an inverter chain with ideal transfer characteristics, and the error probability due to spurious data transfer caused by the thermal noise fluctuation is evaluated as a function of the node switching energy. The maximal error probability at each node allowed by the reliability requirement of the total system leads us to the minimal node energy dissipated per logical switching, which amounts to around 12 eV in the future 1010 gate system operated at a 10 GHz clock rate with a 104 FIT level reliability. In view of the device size-scaling trend of large-scale integrated circuits, the minimal node energy is expected to be reached at a feature size of 10–20 nm.

We characterize the performance of a built-in hot filament broad beam ion source by mass spectrometry, energy analysis, and beam profile measurements. In the ion energy; distribution we detect various peak structures which can be explained by the potential across the ion source and different charge transfer processes. Depending on the typical cross sections for these processes, differences between the energy distributions of the ion species are observed. The total ion current obtained with the source is determined by the ionization rate in the discharge and the current share directed toward the extraction grid system. The performance of the source is strongly dependent on the process gas used. We observe much broader energy distributions in oxygen and nitrogen than in argon. This broadening is explained by spatial inhomogeneities in the discharge region and can be reduced by a suitable setting of the source parameters. The main contribution to the ion flux is caused by species generated directly from the process gas, with important impurities from source materials appearing only with additional chemical reactions in oxygen. (C) 1996 American Institute of Physics.