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This paper is dedicated to laser engraving and drilling process of the alumina ceramics. Both processes are characterized by exquisite features in comparison with conventional ones. The main benefits are high speed, high precision and good quality along with flexibility. Moreover ceramics are hardly processed by conventional methods due to their high hardness and brittleness. Analysis of Nd:YLF laser engraving alumina ceramics concerning the influence of parameters like output power, processing speed and number of runs on various mark characteristics was carried out. Mark width, mark depth and contrast were evaluated and it was found out that output power determines both mark depth and width. Higher power caused generation of deeper and wider marks characterized by high contrast. Processing speed controls the overlapping of spots and the laser-material interaction time, thus having impact on the mark depth and contrast. Laser drilling was examined in dependence of output power that had crucial effect on the hole depth not on diameter. The research clarified that high output powers are necessary for producing deep holes so as high output powers together with low processing speeds are the optimal parameters to get maximal mark width and depth with satisfactory quality during engraving. Samples were analyzed using confocal microscope and contact profilometer.

Laser radiation is used, among others, for surface treatment of various materials. At the Institute of Optoelectronics, under the direction of the late Professor Jan Marczak, a number of works in the field of laser materials processing were performed. Among them special recognition deserves flagship work of Professor Jan Marczak: implementation in Poland laser cleaning method of artworks. Another big project involved the direct method of laser interference lithography. These two projects have already been widely discussed in many national and international scientific conferences. They will also be discussed at SLT2016. In addition to these two projects in the Laboratory of Lasers Applications many other works have been carried out, some of which will be separately presented at the SLT2016 Conference. These included laser decorating of ceramics and glass (three projects completed in cooperation with the Institute of Ceramics and Building Materials), interference structuring medical implants (together with the Warsaw University of Technology), testing the adhesion of thin layers (project implemented together with IFTR PAS), structuring layers of DLC for growing endothelial cells (together with IMMS PAS), engraving glass for microfluidic applications, metal marking, sapphire cutting and finally the production of microsieves for separating of blood cells.

Laser engraving is used for decades as a well-established process e. g. for the production of print and embossing forms for many goods in daily life, e. g. decorated cans and printed bank notes. Up to now it is more or less a so-called fire-and-forget process. From the original artist’s plan to the digitization, then from the laser source itself (with electronic signals, RF and plasma discharge regarding CO 2 lasers) to the behavior of the optical beam delivery — especially if an AOM is used — to the interaction of the laser beam with the material itself is a long process chain. The most recent results using CO 2 lasers with AOMs and the research done with scanning electron microscope (SEM) and confocal laser scanning microscope (CLSM) — as a set for correlative microscopy to evaluate the high speed engraving characteristics — are presented in this paper.

Ultrafast laser micro-machining relies on complex laser-matter interaction processes, leading to a virtually athermal laser ablation. The development of industrial ultrafast laser applications benefits from a better understanding of these processes. To this end, a number of sophisticated scientific models have been developed, providing valuable insights in the physics of the interaction. Yet, from an engineering point of view, they are often difficult to use, and require a number of adjustable parameters. We present a simple engineering model for ultrafast laser processing, applied in various real life applications: percussion drilling, line engraving, and non normal incidence trepanning. The model requires only two global parameters. Analytical results are derived for single pulse percussion drilling or simple pass engraving. Simple assumptions allow to predict the effect of non normal incident beams to obtain key parameters for trepanning drilling. The model is compared to experimental data on stainless steel with a wide range of laser characteristics (time duration, repetition rate, pulse energy) and machining conditions (sample or beam speed). Ablation depth and volume ablation rate are modeled for pulse durations from 100 fs to 1 ps. Trepanning time of 5.4 s with a conicity of 0.15° is obtained for a hole of 900 μm depth and 100 μm diameter.

The industrial market for processing large-scale films has seen dramatic changes since the 1980s and has almost completely been replaced by lasers and digital processes. A commonly used technology for engraving screens, print and embossing forms in the printing industry, well known since then, is the use of RF-excited CO 2 lasers with a beam power up to about 1 kW, modulated in accordance to the pattern to be engraved. Future needs for high-security printing (banknotes, security papers, passports, etc.) will require laser engraving of at least half a million or even more structured elements with a depth from some μm up to 500 μm. Industry now wants photorealistic pictures in packaging design, which requires a similar performance. To ensure ’trusted pulses’ from the digital process to the print result the use of correlative microscopy (CLSM and SEM) is demonstrated as a complete chain for a correlative print process in this paper.

The production and characterisation of a micro-structured FBG force sensor is described. Employing femtosecond laser micro machinery a circumferential ditch of about 30 μm depth and 40 μm width is engraved in the clad of an optical fibre at the centre of a 3 mm long type I fibre Bragg grating (FBG). The purpose of the structure is the enhancement of the force sensitivity characteristics for the measurement of sub-mN forces. Phase-shift spectra occur when axial stress is applied to the fibre. Exploiting this phenomenon experimental tests show a 10% improvement in the sensitivity performance when compared to an unstructured FBG.

The process of ablation in obsidianus lapis is mainly governed by pulse energy from the laser source and scanning speed. The rate of material ablation is influenced by chemical and physical properties. In this work, laser energy at 1064 nm, has been used for ablation behavior in Q-switch regime. A >40 W, average power Nd:YAG source with pulse energies ranging from 3mJ to nearly 7 mJ, achieved surface damages up to 160 μm of depth. Photo-mechanical ablation in terms of scan speed showed a maximum depth of nearly 500 μm at 130 mm/s. The maximum pulse energy of 12 mJ resulted in ablation of 170 μm depth. Highly efficient ablation in obsidianus lapis for artistic work is an interesting field of application.

High-resolution features are key to achieve high performance printed electronics devices such as transistors. Gravure printing is very promising to achieve high resolution in combination with high printing speeds on the order of 1m/s. High-speed gravure has recently been shown to print high resolution features down to linewidths and spacing of 2μm. Whilst this was a tremendous improvement over previous reports, these results had been obtained using silicon printing plates. These silicon printing plates are fabricated using microfabrication techniques which offer several advantages over traditional metal gravure cylinders where the features are defined by techniques such as stylus engraving, laser engraving or etching. This offers much greater precision and design freedom in terms of feature size, surface roughness, cell placement and cell shape. However, rigid silicon printing plates cannot be used in a roll-to-roll printing process that would truly enable low-cost printed electronics. Here we demonstrate for the first time a gravure printing roll that combines the precision of silicon printing plates with the form factor of a metal cylinder. The fabrication process starts with a silicon master whose pattern is replicated by polymer molding. The actual metal printing plate is then built up on the polymer negative of the pattern by a combination of electroless and electroplating. After separation of the polymer and the metal, the metal printing plate can be mounted on a magnetic roll for printing. Printing of highly scaled 2μm features is demonstrated. Different metal surfaces were explored to optimize printing performance and wear during printing.

Manual wavefront holoscopy, or simply manual w-holoscopy, is presented as a simplification of our recently reported concept of wavefront holoscope [B. Perucho and V. Mico, J Biomed Opt. 19(1):16017 (2014)]. The w-holoscope introduces an extremely simple visualization and inspection system for permanent marks in progressive addition lenses (PALs) as an application of digital in-line holography, the digital version allowing visualization (recognition and identification) and characterization (quantitative measurement) of the engravings in PALs. Here, we present a further simplification of such concept by avoiding digital elements in the setup. The layout is extremely simple and defines a new concept of marking reader for visualization and identification of engraved marks in PALs. Experimental results are reported using different PALs.

High security printing as well as ultra high precision engraving need laser resonators with very stable laser beams (600 - 800W) especially in combination with AOMs. Based upon a unique carbon fiber structure - stable within the sub-micrometer range - a new resonator has been developed, accompanied by most recent thermo-mechanical FEM calculations. The resulting beam is evaluated on an automated optical bench allowing to optimize the complete beam path with collimators and AOM. Synchronous on-line evaluation with PyroCams and thus knowledge about how to minimize distortions within the nonlinear elements is presented in this paper.

In micro-analytical chemistry and biology applications, droplet microfluidic technology holds great promise for efficient lab-on-chip systems where higher levels of integration of different stages on the same platform is constantly addressed. The possibility of integration of opto-microfluidic functionalities in lithium niobate (LiNbO 3 ) crystals is presented. Microfluidic channels were directly engraved in a LiNbO 3 substrate by precision saw cutting, and illuminated by optical waveguides integrated on the same substrate. The morphological characterization of the microfluidic channel and the optical response of the coupled optical waveguide were tested. In particular, the results indicate that the optical properties of the constituents dispersed in the fluid flowing in the microfluidic channel can be monitored in situ, opening to new compact optical sensor prototypes based on droplets generation and optical analysis of the relative constituents.

In this paper, we investigated the optical output characteristic of the light guide plate (LGP) with microstructures engraved by a CO2 laser, which is for edge-lit backlight of liquid crystal display or illumination. Especially, the laser-engraving method is suitable for the slim large-sized LGP used in LED TV backlight, and the engraved microstructure has polished surface to contribute to better optical efficiency. For seeking higher optical efficiency, we adopted a LGP with lenticular-arrayed surface (LAS LGP) as the experimental substrate. In order to investigate the effect of the lenticular-arrayed surface on optical output characteristic for the different kinds of the engraved microstructures, we used the laser to directly engrave the flat surface (opposite to the lenticular-arrayed surface) of the LAS LGP with different kinds of microstructures as experimental samples; each sample has one kind of the engraved microstructures on its flat surface. Similarly, we also engraved the same kinds of the microstructures on the flat LGP as a controlled group for comparison. The cross-section profiles of the engraved microstructures on both LAS LGP and flat LGP were measured by a laser confocal microscope. All the samples were further measured for spatial and angular luminance by the BM7 and Conoscope, respectively. In addition, both the experimental data and simulation results were demonstrated and compared to each other in this paper.

In this paper, we investigated the optical characteristic of the light guide plate (LGP) with microstructures engraved by a CO 2 laser. The LGP is for edge-lit backlighting of liquid crystal display. Traditionally, the microstructures on largescaled LGP are formed by screen-printing, which are hardly formed by inject molding. However, the screen-printed LGP highly scatters light and has lower optical efficiency. Therefore, a method was proposed to use the laser to directly engrave the flat surface of a bare LGP with microstructures. The engraved LGP has better optical performance due to the polished surface of the engraved-microstructures, and can be used for large-scaled application such LCD TV backlighting. We used different processing parameters to engrave the microstructures of 11 different shapes on a bare LGP and measured the cross-sectional dimensions of the microstructure. Among them, five kinds of shapes were chosen to be engraved on the bare LGPs respectively as samples. The five LGP samples were measured for spatial and angular luminance by the BM7 and Conoscope. With difference in the profiles of the microstructures, the angular distributions of light emitting from the LGP also differ. All the experimental data of the samples were compared with one another and the on-axis luminance of the best LGP sample could potentially increase 50% more than the reference sample if a proper optical film was chosen to accompany it.

We present a novel form of hollow-core waveguiding that enables chip-scale integration. Light propagates in air along a zig-zag path between very highly-reflective Si metastructures comprised of a single layer of sub-wavelength high-contrast gratings (HCGs) without the aid of sidewalls. Top and bottom subwavelength HCGs separated by 9um of air and with periodicity perpendicular to the propagation of light reflect light at shallow angles with extremely low loss. The HCGs are patterned on SOI wafers with 340 nm-thick Si device layers engraved in a single etch step, and have been measured to have a 0.37 dB/cm propagation loss. Our work demonstrates the light-guiding properties of HCG hollow-core waveguides with a novel form of lateral beam confinement that uses subtle reflection phase changes between core and cladding HCG regions capable of bending light around 30 mm radius-of-curvature tracks.

In order to minimize thermal load to the workpiece pico- and femtosecond lasers gain an increasing market share in industrial applications such as surface structuring or thin film selective ablation. Due to nonlinear absorption they are capable to process any type of material (dielectrics, semiconductors, metals) and provide an outstanding quality suppressing heat affects on the workpiece. In this paper, we report on results about surface engraving of metals (Al, Cu, Mo, Ni), semiconductor (Si) and polymer (PC) using a picosecond thin disk Yb:YAG-amplifier, which could be used in the picosecond regime as well as in the femtosecond regime by simply changing the seed laser source. In the picosecond regime the oscillator pulses, ranging from 10 to 34ps, can be directly amplified which leads to a quite simple and efficient amplifier architecture. On the other hand, a broadband femtosecond oscillator and a CPA configuration can be used in order to obtain pulse duration down to 900fs. We compare these results to recently obtained achievements using commercial femtosecond lasers based on Yb-doped crystals and fibers and operating at comparable output power levels, up to 15Watt. Finally, we have considered etch rate and process efficiency for both ps- and fs-regimes as a function of average power, of fluence and of intensity.

Dynamic Pulsing is demonstrated using a pulsed MOPA fiber laser at 1064nm. The output of the MOPA laser is a pulsed profile consisting of a burst of closely spaced pulses. Tests were performed under several materials with pulse bursts ranging from 10ns to 1μs and operating from 500kHz down to single shot. In particular, percussion drilling in stainless steel is demonstrated showing improvements in quality and speed of the process. These profiles allow high flexibility and optimization of the process addressing the specificity of the end application. Dynamic Pulsing allows the same MOPA fiber laser to be used in diverse materials as well as different processes such us marking, drilling, scribing and engraving. The pulsed fiber laser used in this study is a MOPA-DY by Multiwave Photonics. It is based on a modulated seed laser followed by a series of fiber amplifiers and ending with an optically isolated collimator. This pulsed laser model has an output in such a way that each trigger produces a fast burst of pulses, with a repetition frequency within the burst of the order of tens of MHz. Within the burst it is possible to change the number of pulses, the individual pulse profile, burst pulse period and even to generate non-periodic burst pulse separations. The laser allows full freedom for all these combinations. The study here reported compares the impact of pulse peak power, number of pulses within a burst and the pulse burst period, on process quality (heat affected zone, debris, hole uniformity) and drilling yield.

A Petawatt facility called PETAL (PETawatt Aquitaine Laser) is under development near the LIL (Ligne d'Integration Laser) at CEA Cesta, France. PETAL facility uses chirped pulse amplification (CPA) technique [1]. This system needs large pulse compression grating exhibiting damage threshold of more than 4 J/cm 2 normal beam at 1.053μm and for 500fs pulses. In this paper, we study an alternative design to the classic multilayer dielectric (MLD) grating [2] called "mixed metal-multilayer dielectric grating" (MMLD). This design consists in a gold reflective layer coated with a few pairs of HfO 2 /SiO 2 [3]. The top low index SiO2 layer of the stack is then engraved to receive the grating. We evidenced in a previous work that leads to high efficient pulse compression gratings [3]. We have shown in last Boulder Damage Symposium that mixed mirror is equivalent to a "classic" MLD mirror [4]. We herein detail the damage performances obtained on the MMLD gratings and compare them with these of MLD gratings.

Natural lithography is realized by spin-coating of nanoparticles. The surface textured LED s and nanorod structured LEDs have been made successfully. Concentrated radiation profiles of nanorod structured and surface textured LED are both observed. We fabricate these nano-structure by nature lithography method which use silica nanosphere as etching mask. The SiO 2 grown by PECVD is used as a space layer to realize the nanorod LED. Furthermore, we suggest a light guided concept of the highly concentrated phenomena. The highest output power density of nanorod LEDs is achieved. The reversed current of nanorod LEDs is also reduced down to nA level.

Optical devices are components which require sophisticated equipment and technically skilled manpower for device fabrication and assembling and most of the production costs are on the device assembly. However, the next generation optical components may not be devices assembled at the production line but it will be based on the concept of 'do-it yourself' optical devices. We proposed a simple low-cost acrylic-based Y-branch POF coupler which can be assembled easily by the end users themselves. The device is composed of three sections: an input POF waveguide, an intermediate adjustable hollow waveguide taper region and output POF waveguides. Low cost acrylic-based material has been used for the device material. A desktop high speed CNC engraver is utilized to produce the mold inserts used for the optical device. In addition to the engraved device structure, 4 holes are drilled at each corner to allow a top plate to be screwed on top and enclosed the device structure. Included with this POF coupler assembly kit will be the mold insert, top acrylic block, input and output POF fibers (cleaved and stripped with different stripping lengths) and connecting screws. The short POF fibers are inserted into the engraved slots at the input and output ports until the fibers are positioned just before or butt-coupled to each other. The assembling is completed when the top plate is positioned and the connecting screws are secured. The POF coupler has an average insertion loss of 5.8 ± 0.1 dB, excess loss of 2.8 dB and a good coupling ratio of 1:1.

The most important factor in extreme ultra violet (EUV) mask process is thickness variations which caused by resist dark loss, absorber etching and capping layer durability of cleaning chemical at each layer. For example if multilayer (M/L) is damaged due to 2.5nm capping layer loss after cleaning, it means it is impossible to get sufficient reflectance to make proper EUV mask.

As the new method of machining, laser ablation has a lot of attractive advantages. The possibilities of dead end engraving and stable long term machining would be the great merits of micro-patterning to large metal mold which is used to the optical sheets for flat panel display for example. We developed pico-second laser machining system and manufactured micro-patterns on metal mold surface. And from those sample-machining results, we concluded it is possible to adapt this system to metal mold micro-pattern machining and decided to continue our development of laser machining.

Dependences of characteristics of deep silicon etching on various process parameters are investigated. The method of planning multifactorial experiment is applied to a finding of the optimum recipes providing high selectivity to a mask and decrease of ARDE. Results of research are used by manufacturing of real MEMS structures.

An experimental measurement by using Laser Induced Breakdown Spectroscopy (LIBS) and Photo-acoustic Induced by Laser Ablation (PILA), in order to monitoring the microcraks formation inside the glass induced by laser pulses is presented in this work. The laser was operated in both single pulse and multi-pulse Q:Switched regime using a passive Cr:YAG crystal as switching el ement. The LIBS spectra captured inside the glass avoid identifying the sample composition without influence of surrounding atmosphere like occurs if the spectra are obtained on the surface. On the other hand, the PILA signal permits to monitor the process and its dependence from the number and intensity of micro-pulses. Keywords: laser, glass, ablation, acoustic signal, plasma 1. INTRODUCTION The micro-cracks formation in transp arent materials is produced when an intense laser pulse is focused inside the volume of the glass, providing light fluency that exceeded the material breakdown threshold. Numerous works have been dedicated to this phenomenon, given his importance for the preservation of optical components, irradiated by high energy pulse lasers [1,2]. More recently, the effect of laser breakdown of transparent materials has spent the threshold of the laboratory research, to be used widely in the industry of decorative engraving, in order to insert three-dimensional figures in glass cubes, obtaining these objects a wide commercial diffusion. Anyway, the study of laser-induced micro-crack formation continues having a growing presence in the scientific literature, since there are a potential application of major interest likes, for example, the information store or the obtaining of new devices related to the modification of the refraction index inside the material [3,4]. There are several aspects that are studied in the r ecent reports: The existence of accumulative effects that diminish the breakdown threshold, the form in which they appear under conditions of irradiation with ultrashort pulses, the effect of laser wavelength and others. Both for the laboratory studies and for industrial purposes, it has a great importance to develop monitoring methods that allow to determine the ideal parameters of crack formation and to check his occurrence. In the report of Navarrete and colleagues [5], they propose the method of monitoring of the acoustic signal intensity, being demonstrated as this technique can serve perfectly to determine the damage threshold by precise and simple way. In our work, we use the LIBS spectroscopy, as a method that also allows to monitoring the process, by using the information obtained from the emission of plasma generated when laser pulses irradiates inside glass samples. The LIBS technique has the aptitude to detect, to identify, and quantify the chemical composition, in principle, of any material [6]. Between many applications, there have been realized studies of

For lithography technology to support the scaling down of semiconductor devices, 193-nm immersion exposure processing is being introduced to mass-production at a rapid pace. At the same time, there are still many unclear areas and many concerns to be addressed with regards to defects in 193-nm immersion lithography. To make 193-nm immersion lithography technology practical for mass production, it is essential that the defect problems be solved. Importance must be attached to understanding the conditions that give rise to defects and their transference in the steps between lithography and etching processes. It is apparent that double patterning (DP) will be the mainstream technology below 40nm node. It can be assumed that the risk of the defect generation will rise, because the number of the litho processing steps will be increased in DP. Especially, in the case of Litho-Etch-Litho-Etch (LELE) process, the concept of defect transfer becomes more important because etch processing is placed between each litho processing step. In this paper, we use 193-nm immersion lithography processing to examine the defect transference from lithography through the etching process for a representative 45nm metal layer substrate stack for device manufacturing. It will be shown which types of defects transfer from litho to etch and become killer defects.

The cost of ownership (COO) of candidate technologies for 32 nm and 22 nm half-pitch lithography is calculated. To more accurately compare technologies with different numbers of process steps, a model that includes deposition, etching, metrology, and other costs is created. Results show lithography COO for leading edge layers will increase by roughly 50% from the 45 nm to the 32 nm half-pitch nodes. Double patterning and extreme ultraviolet lithography (EUVL) technologies have roughly the same COO under certain conditions. For 22 nm half-pitch nodes, EUVL has a significant cost advantage over other technologies under certain mask cost assumptions. Double patterning, however, may be competitive under worst case EUVL mask cost assumptions. Sensitivity studies of EUVL COO to throughput and uptime show EUVL may be cost-competitive at lower uptime and throughput conditions. In spite of these higher costs, total lithography costs for 32 nm and 22 nm half-pitches remain within reach of the Moore's Law trend. Finally, the COO of 450 mm lithography is calculated and shows the expected cost reduction is between 0% and 15%.

New dispersive elements providing relative high resolution (R=2200) have been recently incorporated in the near infrared spectrograph LIRIS. These elements are founded on a rather novel design based on a diffractive pattern engraved in fused silica, which is placed between two prisms. These new components are pushing forward the scientific capabilities of the instrument by enhancing the medium resolution spectroscopic mode of operation. Details on the design, specifications and measured performances, as well as aspects related to the integration and astronomical tests in the instrument are presented.

Conventionally, pattern inspection is performed on completed reticles. In other words, the completed circuit pattern on a reticle is inspected after etching and removing the resist. This pattern consists of the transmission region (Qz), half transmission region (MoSi) and shading region (Cr). If the process stage where a detected defect occurred can be specified, detection can be made at an earlier process stage, enabling an improvement in the process and/or yield. When inspecting the resist pattern on a reticle before the etching process, points such as the endurance of the resist against the inspection light beam and the effect of the gas that is generated by irradiation must be considered. In addition to there being no damage to the resist pattern, there must also be no contamination of the optical elements caused by outgases. To prevent contamination, therefore, we developed a cassette-type enclosure with gasproof windows in which the reticle is set, thus shutting out outgases. Also, because the image of the resist pattern is very different from a normal pattern, we needed to develop various functions, such as algorithms, to detect defects on the resist pattern. This time, we have successfully developed a resist pattern inspection function for the LM7500 reticle inspection system. This function enables both die-to-database and die-to-die inspection and features an inspection light wavelength of 266 nm, allowing the detection of smaller defects that could not be detected with an i-line (365 nm) inspection system.

We utilized a newly developed low acceleration voltage FIB (Focused Ion Beam) system a nd evaluated the process for repairing the absorber layer on EUVL mask. During the etching of the absorber layer, which is a step in conventional repair technique, a phenomenon of side-etching of Ta-nitride layer with XeF 2 gas was observed. This phenomenon was considered to be caused by the isotropic etching of the Ta-nitride layer with XeF2 gas. We then added another gas for etching and evaluated the new process to prevent the side-etching of Ta-nitride layer. In this paper, we will report four evaluation results of EUVL mask pattern defect repair using FIB-GAE (Gas Assisted Etching). The first one is the problem of pattern topography after conventional repairing process and the reaction mechanism of gas assisted etching of Ta based absorber. The second evaluation result is addressed in two parts. One is the evaluation of a new gas assisted etching process that employs an additional gas that has an ability to control the etching rate of absorber layer. The sec ond part addresses the repairing accuracy of EUVL mask pattern. The third is the basic etching performance e.g. etching rate of Ta based absorber, Cr based buffer, and Si based capping layer. The fourth and the last evaluation is the application of the newly developed gas assisted etching process on programmed bridge defect in narrow pitched L/S patterns. Keywords: EUV, mask, repair, FIB, gas assisted etching

As technology advances with feature size shrinking for the state-of-the-art integrated circuit (IC) fabrication, the degree of reduction in critical dimension (CD) features on a photomask shrinks at a faster pace, thanks to the ever aggressive optical proximity correction (OPC) design. In addition to stri ngent CD requirement, defect control has also become one of the most difficult challenges for advanc ed photomask manufacturing as a result of reduction in printable defect size. Therefore, keeping a photomask etching chamber at an optimal condition becomes very critical for controlling in both defectivity and CD fidelity. In the present study, analyses on optical emission spect rum (OES) collected in an Applied Materials’ Tetra TM chrome etch module have been performed to understand (1) the impact of Cr etching on the chamber condition, and (2) the effectiveness of in-situ chamber dry clean for chamber conditio n control and potential particle reduction. Results showed that, with the right selection of chamber materials (to be compatible with process chemistry and etching condition), the main impact of Cr etching on chamber condition and particle performance is from resist etch-by-products. Various plasma dry clean chemistries have been explored to address the effectiveness for the removal of such etch-by-products. As a result, an in-situ chamber clean (ICC) procedure is de veloped and has been validated to be production-worthy for desired particle control and chamber stability control. Keywords : Mask Etch, Dry clean, in-situ cham ber clean, defect, particle control

In nanoimprint with UV curable resin, a mold fabricated by etching quartz by using Cr as a hard mask is generally used. For fine pattern fabrication, Cr fine pattern etching technology is very important. Usually, the realization of enough resolution needs a resist thickness reduction, which, however, makes it difficult to etch extremely fine Cr features with vertical sidewalls. Here, we propose a brand-new method called "reverse EB process". In this method, an electron-beam (EB) resist pattern is first reversed by a plasma-robust material, with which as a mask, the Cr is then etched to form a hard mask for the mold etching. By this process, we have realized a quartz mold with patterns of 16nm in half pitch at minimum.

In this work, the authors demonstrate the suitability of Step and Flash® Imprint Lithography (S-FIL®) materials as a mask for patterning 42 nm and 32 nm half pitch features into a hardmask material. We present a zero etch-bias process with good silicon oxide to imprint resist selectivity and excellent line-width roughness (LWR) control. We demonstrate the required etch processes and mean value and uniformity of the residual layer thickness (RLT) necessary to maintain cross wafer CD uniformity for 42 nm and 32 nm half pitch dense lines. Finally, the authors present a mechanism for targeting the critical dimension by control of the imprint resist volume.

Semiconductor manufacturing technology has shifted towards finer design rules, and demands for critical dimension uniformity (CDU) of resist patterns have become greater than ever. One of the methods for improving Resist Pattern CDU is to control post-exposure bake (PEB) temperature. When ArF resist is used, there is a certain relationship between critical dimension (CD) and PEB temperature. By utilizing this relationship, Resist Pattern CDU can be improved through control of within-wafer temperature distribution in the PEB process. Resist Pattern CDU improvement contributes to Etching Pattern CDU improvement to a certain degree. To further improve Etching Pattern CDU, etcher-specific CD variation needs to be controlled. In this evaluation, 1. We verified whether etcher-specific CD variation can be controlled and consequently Etching Pattern CDU can be further improved by controlling resist patterns through PEB control. 2. Verifying whether Etching Pattern CDU improvement through has any effect on the reduction in wiring resistance variation. The evaluation procedure is as follows.1. Wafers with base film of Doped Poly-Si (D-Poly) were prepared. 2. Resist patterns were created on them. 3. To determine etcher-specific characteristics, the first etching was performed, and after cleaning off the resist and BARC, CD of etched D-Poly was measured. 4. Using the obtained within-wafer CD distribution of the etching patterns, within-wafer temperature distribution in the PEB process was modified. 5. Resist patterns were created again, followed by the second etching and cleaning, which was followed by CD measurement. We used Optical CD Measurement (OCD) for measurement of resist patterns and etching patterns as OCD is minimally affected by Line Edge Roughness (LER). As a result, 1. We confirmed the effect of Resist Pattern CD control through PEB control on the reduction in etcher-specific CD variation and the improvement in Etching Pattern CDU. 2. The improvement in Etching Pattern CDU has an effect on the reduction in wiring resistance variation. The method for Etching Pattern CDU improvement through PEB control reduces within-wafer variation of MOS transistor's gate length. Therefore, with this method, we can expect to observe uniform within-wafer MOS transistor characteristics.

Semiconductor manufacturing technology has shifted towards finer design rules, and demands for critical dimension uniformity (CDU) of resist patterns have become greater than ever. One of the methods for improving CDU of resist pattern is to control the temperature of post-exposure bake (PEB). When ArF resist is used, there is a certain relationship between critical dimension (CD) and PEB temperature. By utilizing this relationship, Resist Pattern CDU can be improved through control of within-wafer temperature distribution in the PEB process. We have already applied this method to Resist Pattern CDU improvement and have achieved these results. In this evaluation, we aim at: 1. Clarifying the relationship between the improvement in Resist Pattern CDU through PEB temperature control and the improvement in Etching Pattern CDU. 2. Verifying whether Resist Pattern CDU improvement through PEB temperature control has any effect on the reduction in wiring resistance variation. The evaluation procedure is: 1. Preparation of wafers with base film of doped Poly-Si (D-Poly). 2. Creation of two sets of samples on the base, a set of samples with good Resist Pattern CDU and a set of samples with poor Resist Pattern CDU. 3. Etching of the two sets under the same conditions. 4. Measurements of CD and wiring resistance. We used Optical CD Measurement (OCD) for measurement of resist pattern and etching pattern for the reason that OCD is minimally affected by Line Edge Roughness (LER). As a result, we found that; 1. The improvement in Resist Pattern CDU leads to the improvement in Etching Pattern CDU . 2. The improvement in Resist Pattern CDU has an effect on the reduction in wiring resistance variation. There is a cause-and-effect relationship between wiring resistance variation and transistor characteristics. From this relationship, we expect that the improvement in Resist Pattern CDU through PEB temperature control can contribute to device performance improvement.

An etch-stop phenomenon taking place in Cl2/O2/N2 plasma was investigated by means of the actinometry technique as well as using PlasmaVolt and PlasmaTemp in-situ sensor wafers from K-T promesys of KLA Tencor. The temperature of TCP quartz window was determined to increase from 50°C to more than 100°C during sequential plasma processing that in turn induces a plasma composition change. Based on the optical spectra a 20% increase in both atomic [O] and [Cl] concentrations was determined to take place in Cl2/O2/N2 plasma used for STI etching. Performing experiments on the blanket wafers the dependence of the etch-stop on O2-flow, pressure, TCP power, wafer temperature and quartz window temperature was determined. The values of RF voltage and temperature were measured locally at different positions on the wafer surface providing additional information about plasma homogeneity. Finally, the results are discussed in terms of the well-known recombination model considering the increase of [O] concentration results in the etch stop in the middle of the wafer.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

From the fifteenth to the nineteenth centuries, prints were a common form of visual communication, analogous to photographs. Copperplate prints have many finely engraved black lines which were used to create the illusion of continuous tone. Line densities generally are 100-2000 lines per square centimeter and a print can contain more than a million total engraved lines 20-300 micrometers in width. Because hundreds to thousands of prints were made from a single copperplate over decades, variation among prints can have historical value. The largest variation is plate-related, which is the thinning of lines over successive editions as a result of plate polishing to remove time-accumulated corrosion. Thinning can be quantified with image analysis and used to date undated prints and books containing prints. Print-related variation, such as over-inking of the print, is a smaller but significant source. Image-related variation can introduce bias if images were differentially illuminated or not in focus, but improved imaging technology can limit this variation. The Print Index, the percentage of an area composed of lines, is proposed as a primary measure of variation. Statistical methods also are proposed for comparing and identifying prints in the context of a print database.

Application of lasers for print form fabrication plays an increasingly important role in the printing industry due to the high machining rate, the high spatial resolution and the ability of digital modulation. This paper gives an overview of our laser based processes in gravure and embossing with a focus on micro-structuring of gravure print forms by direct laser ablation. The precise large scale micro-fabrication by laser engraving is the fastest and most versatile process for gravure cylinder fabrication (ablation rate up to 1 cm 3 /min). Direct laser engraving into metallic cylinders is performed with high power Q-switched Nd:YAG laser systems and fiber lasers at up to 100 kHz repetition rate, tuned for high reproducibility and stability of the mean pulse energy (σ 2 Flexible aspect ratios and designs of the cell profile are achieved by fast modulation of the laser beam profile for each single pulse. This allows for optimization of the cell shape to get the best ink transfer interaction on a specific print substrate. New experiments with high power fiber lasers (cw lasers and pulsed MOPA systems > 500W@ 100kHz) resulted in improved cell precision, screen resolution and production efficiency. Future large scale cylinder engraving with ultra short pulse lasers (ps) is discussed.

We report on an industrial ultrafast laser system for internal marking and engraving of transparent materials. Current engraving techniques, using nanosecond infrared or UV laser, are either limited to surface marking, or create thermal stress which can lead to fracture of material. Using an infrared ultrafast laser, we describe an industrial equipment able to non-aggressively mark alphanumeric or datamatrices at a high speed, with a high readability. Anti-counterfeiting and normative applications will be presented, as well as integration on a production line.

Thick GaN films were grown on sapphire in a home-made vertical HVPE reactor. Effect of nucleation treatments on the properties of GaN films was investigated, including the nitridation of sapphire, low temperature GaN buffer and MOCVD-template. Various material characterization techniques, including AFM, SEM, XRD, CL and PL have been used to assess these GaN epitaxial films. It was found that the surface of sapphire after high temperature nitridation was flat and showed high density nucleation centers. In addition, smooth Ga-polarity surface of epitaxial layer can be obtained on the nitridation sapphire placed in air for several days due to polarity inversion. This may be caused by the atoms re-arrangement because of oxidation. The roughness of N-polarity film was caused by the huge inverted taper domains, which can penetrate up to the surface. The low temperature GaN buffer grown at 650 °C is favorable for subsequent epitaxial film, which had narrow FWHM of 307 arcsec. The epitaxial growth on MOCVD-template directly came into quasi-2D growth mode due to enough nucleation centers, and high quality GaN films were acquired with the values of the FWHM of 141 arcsec for (002) reflections. After etching in boiled KOH, that the total etch-pit density was only 5×10 6 cm -2 illustrated high quality of the thick film on template. The photoluminescence spectrum of GaN film on the MOCVD-template showed the narrowest line-width of the band edge emission in comparison with other two growth modes.

One of the key issues in extreme ultraviolet lithography (EUVL) is the influence of defects on a mask because of the high printing resolution of EUVL. In order to address this issue, it is necessary to estimate the critical size of an absorber pattern defect and that of a repaired defect. The repair of an opaque defect by milling or of a clear defect by deposition might not be perfect; so the area, height, and optical constant of the repair material must be taken into consideration. By estimating the threshold of calculated aerial images, the critical dimension (CD) that can be printed was found to equal the square root of the defect area. For the repair of opaque defects, residual Ta was found to be more likely to cause poor printing than the etching of the multilayer by excessive milling. Since a clear defect is repaired with Ta with the same optical properties as the absorber material, the CD error in printing is mainly caused by the repair of a CD error and is not caused by an error in height that is less than ±25% of the height of the Ta absorber. The optimal optical constant of the repair material was estimated by varying the refraction coefficient from 0.9199 to 0.9999 and the extinction coefficient form 0.0001 to -0.0451. We found that carbon is a useful repair material that provides a CD error of at most ±0.5 nm around a defect with an area of 64 nm because the maximum refraction should be below 0.97.

As mask feature size decreases, etch bias control during Cr and shifter etch becomes more critical factor in Embedded Phase Shifter Mask (EPSM) mask making processes. Since the etching characteristics of the shifter materials, Molybdenum Silicide (MoSi), are sensitive to etching surface condition, Critical Dimension (CD) performance of the shifter layer strongly depends on incoming surface condition from Cr etch. In this paper, lateral etch component of MoSi etch was investigated as a function of various substrate conditions so that a new in-situ plasma treatment was suggested to control the CD bias during MoSi etch. The CD performance was characterized within the surface treatment plasmas and also correlated with some plasma parameters and substrate temperature. As a result, it was found that plasma surface modification could be an in-situ technique to better control the shifter CD in EPSM process and an essential option for redundancy tools in mask production environment.

The moire fringes method and their analysis up to medical and entertainment applications are discussed in this paper. We describe the procedure of capturing 3D images with an Inspeck Camera that is a real-time 3D shape acquisition system based on structured light techniques. The method is a high-resolution one. After processing the images, using computer, we can use the data for creating laser fashionable objects by engraving them with a Q-switched Nd:YAG. In medical field we mention the plastic surgery and the replacement of X-Ray especially in pediatric use.

Although photomask defect repair tools based on FIB, AFM and pulsed laser are mainly used in current production lines, there is a possibility they will not meet the requirements of 45nm generation photomasks. The EB repair tool is one of the candidates that has a possibility of meeti ng those requirements. The EB repair tool, MeRiT-MG TM , has already been announced by Carl Zeiss GmbH. The basic performance of this tool has been reported. 1) Recently MoSi mask is most commonly used in leading edge devices, and def ects are mainly opaque type. For this reason, the performance of EB-repair tool for MoSi etching sh ould be investigated. In this paper, we will report the evaluation results of MeRiT-MG TM and consider whether this tool has a possibility of meeting the requirements of 45nm generation photomasks. In order to evaluate the performance of MeRiT-MG TM , we prepared 180nm half pitch line & space pattern of ArF-att.PSM with programmed defects. Thes e programmed defects are not only simple extrusion shape but also of various shapes and sizes. By using these defects, we made practical experiment which would happen in real production line. Keywords: EB-Repair, MoSi, Etching, photomask

As the geometry of semiconductor devices continue to scale down, high-NA imaging will be used to enhance the resolution. Sub-resolution assistant features are used to gain depth of focus at the wafer. One of the challenges in patterning small assistant features during mask fabricating is resist collapse. Reducing resist thickness is one of the solutions. This necessitates an increase in the selectivity of chromium (Cr) to photo-resist (PR). The selectivity determines the PR remaining on the mask after Cr etching. Insufficient remaining PR will induce pinhole-type clear defect and poor line edge roughness (LER). In this paper, the Cr-to-PR selectivity was studied under induced couple plasma (ICP) and quasi-remote plasma environment. PR remaining, etching bias, and critical dimension uniformity (CDU) are the main subjects for evaluation. To understand the etching behavior for higher selectivity, design of experiment (DOE) L4 by Taguchi method is used to find the dominating factors. By adopting the optimized etching recipe, the resist can be thinned down to effectively improve its collapse margin, especially for smaller assistant features. The results show that 72-nm assistant features on mask can be patterned for early 32-nm node development. This paper also suggests several approaches that can be used to reduce the required resist thickness, such as hard-mask, film thickness reduction, and etcher hardware modification.

Etching of TaBO/TaBN absorbers on EUVL masks was studied. The self-mask strategy and etch selectivity optimization were used for obtaining the best etch CD performance. Gibbs Energy Minimization was used for determining etch gas selection and product volatility. Calculated results suggest the use of a two-step etch process, i.e. using fluorinecontaining gas to etch the antireflective (AR) layer and using chlorine-containing gas to etch the bulk absorber beneath AR. High selectivity of TaBN-to-TaBO was obtained and the AR hard mask function was proven. By using this method, one EUVL mask can be used many times by selectively exposing portions of a mask during etch. A profilometer was used for etch product characterization and etch CD results were verified by using CD SEM measurement. Optimal conditions developed on the Applied Materials Tetra Mask Etch System by using just one mask gave etch CD bias of 3 nm, etch CD uniformity of

As a promising way to scale down semiconductor devices, 193-nm immersion exposure lithography is being developed at a rapid pace and is nearing application to mass production. This technology allows the design of projection lens with higher numerical aperture (NA) by filling the space between the projection lens and the silicon wafer with a liquid (de-ionized water). However, direct contact between the resist film and water during exposure creates a number of process risks. There are still many unresolved issues and many problems to be solved concerning defects that arise in 193-nm immersion lithography. The use of de-ionized water during the exposure process in 193-nm immersion lithography can lead to a variety of problems. For example, the trapping of microscopic air bubbles can degrade resolution, and residual water droplets left on the wafer surface after immersion exposure can affect resolution in the regions under those droplets. It has also been reported that the immersion of resist film in de-ionized water during exposure can cause moisture to penetrate the resist film and dissolve resist components, and that immersion can affect critical dimensions as well as generate defects. The use of a top coat is viewed as one possible way to prevent adverse effects from the immersion of resist in water, but it has been reported that the same problems may occur even with a top coat and that additional problems may be generated, such as the creation of development residues due to the mixing of top coat and resist. To make 193-nm immersion lithography technology practical for mass production, it is essential that the above defect problems be solved. Importance must be attached to understanding the conditions that give rise to residual defects and their transference in the steps between lithography and the etching/cleaning processes. In this paper, we use 193-nm immersion lithography equipment to examine the transference (traceability) of defects that appear in actual device manufacturing. It will be shown that defect transfer to the etching process can be significantly reduced by the appropriate use of defect-reduction techniques.

High resolution patterning of LED's has shown the potential to significantly increase the light output. There are 3 different imprint strategies being proposed to manufacture these devices. These imprint solutions and all the support equipment for cleaning, coating, and etching form an imprint cell. This paper will compare the imprint cell and process solutions. Imprint is probably the only patterning technology that can deliver sub 100 nm features at a low enough cost to be of interest to the LED manufacturers. Patterning fine features on LED wafers must be able to deal with rough, non flat wafers. The competing imprint solutions rely on either; 1) flexing the wafer or 2) flexing the template or 3) making the surface of the template compliant, The published data on wafer non-flatness, and the compliance of the different solutions will be compared. Process solutions are still needed to eliminate residual non-conformality. The overall margin of the different process solutions will be compared, multilayer processes can tolerate 2.5 x larger residual layer variation than single layer imprint.

We have clarified that the low-damage, high-resolution defect inspection of the photo resist patterns is ensured by the electron-beam defect inspection equipment for 32-nm generation and beyond. It has first been confirmed that the CD variations on the 65-nm width line structure formed on an ArF resist under general inspection conditions are equal to or less than the CD variations due to a general CD-SEM. We have also succeeded in understanding the resist deterioration mechanism when the ArF resist is exposed to e-beams. This understanding has led us to learn that the layer that, located in the vicinity of the resist surface, is deteriorated by e-beams has its etching rate lowered to cause even improvement on the etching resistance. These findings have enabled us to use inspection conditions that cause lower damage to resists. By using those conditions, we have been able to inspect ArF resist line-space structure wafers with line width of 65nm and pitch width of 140nm. The inspection successfully detected 15 to 20nm programmed extrusion defects with a capture rate of at least 95% and a nuisance rate of 5% or less. It has thus been revealed that e-beam defect inspection equipment are useful for inspecting defects on resist wafers with 32-nm generation and beyond.

The correlation between the amount and rate of etching and various properties of organic film for multi-layer resist (MLR) was investigated. The etching critical dimension (CD) of 140-nm pitch interconnects is controlled by the etching conditions as well as by the properties of the organic film used as the bottom layer resist. Six organic films were tested that had different densities, hardness values, refractive indexes, and FT-IR peaks. Patterned samples of these films were exposed using electron projection lithography. The results showed amount of side etching, which effects the etching CD of interconnects, of the bottom layer depended on the etching rate of the film. In turn, the etching rate depended on a film's hardness and refractive index, but not on its density. The etching rate decreased with increasing hardness and with increasing refractive index in the visible wavelength spectrum. Consequently, the etching CD of interconnects can be better controlled by using an organic film as the bottom layer resist when the film has appropriate properties.

The improvement of devices performances is due to many factors such as new architectures, new materials and better lithography resolution. Resist chemical components play a key role in the final performance of a specific resist. In addition to resist characteristics such as: resolution, etching selectivity, the final resist line edge roughness (LER) and line width roughness (LWR) becomes a critical issue because it can degrade resolution and linewidth accuracy and causes fluctuations of transistors performances1,2. LER and LWR are currently calculated with top-down view SEM images. With chemically amplified resists, we can play on photoacid generator size to partially control acid diffusion length during the post exposure bake. In this paper we propose to compare two techniques, the CD-AFM and CD SEM in order to study the impact of various acid diffusion lengths on LER and LWR. The results show that globally the two techniques agree on most of the results and show the same trends. However, when the profiles vary the linearity between the two techniques can vary drastically. In addition, as a complementary technique to the CD-SEM technique, the CD-AFM gives additional information such as height (top loss), top rounding and sidewall angle which allow us to understand more deeply the impact of PAG size. Therefore, these additional information have a non negligible impact on near term new resist development and lithography processes development. As an illustration of this work, we will present the latest resist development coming from this understanding and leading to very low LER and LWR. Finally, we will propose strengths and weakness of each technique.

As semiconductor process technology moves to smaller generations (65nm and beyond), the contact pattern printing becomes the most difficult challenge in the lithography field. The reason comes from the smaller feature size and pitch of contact/via pattern printing that is similar to 2D (two-dimensional) patterning. Contact and via patterns need better image contrast than line/space patterns in pattern printing. Hence, contact/via printing needs a higher k1 value than others. In 65nm generation experience, the k1 is ~0.44 on a 0.85 NA exposure tool. A larger NA exposure tool is expensive and developed slower than the motivation of generation. Hence, the process is difficult to achieve by obtaining larger NA exposure tools. The k1 requirement of 45nm (logic) contact pattering (minimum pitch: 140nm) is ~0.34 on a 0.93 NA exposure tool that is available currently. RET (resolution enhancement technology) is necessary to achieve the difficult process goal. Splitting pitch technology is an RET approach to solving 45nm contact pattering. In this paper, we use a 2P1E (2 photo exposure and 1 etching) approach to meet our process requirements. The original layout is split into dense pitch pattern and semi-iso to iso pattern parts by software. Utilizing strong OAI (off-axis-illumination) on dense pattern part and weak OAI on semi-iso to iso pattern part can obtain better process results.