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We developed a novel 512 x 320 tip-tilt micro mirror array (MMA) together with the entire related technology platform, including mirror fabrication process, integrated CMOS address circuitry and external drive electronics. The MMA itself consists of 2axis-tip-tilt actuators at 48μm pixel size, allowing a continuous pure tip-tilt motion up to 3.5° in arbitrary directions, fully calibratable at standard deviations of better than 0.025°. The mirrors are realized within a 2-level architecture defined by three structural layers, two for hinge and reinforcement suspension and one for the overlying mirror. They are fabricated by surface-micromachining within a fully CMOS compatible process. MMA programming is accomplished by an underlying CMOS backplane supporting drive voltages up to 27V and frame rates up to 3.6kHz.

The application of phasefluid based intelligent fluids® in the field of photoresist stripping was studied. Due to their highly dynamic inner structure, phasefluids penetrate into the polymer network of photoresists and small gaps between resist layer and substrate and lift off the material from the surface. These non-aggressive stripping fluids were investigated regarding their efficiency in various resist stripping applications including initial results on copper metallization. Furthermore intelligent fluids® have been evaluated on an industry standard high volume single wafer cleaner. A baseline process on 300 mm wafers has been developed and characterized in terms of metallic and ionic impurities and defect level. Finally a general proof of concept for removal of positive tone resist from 300 mm silicon wafers is demonstrated.

Electron optics can assist in the fabrication of semiconductor devices in many challenges that arise from the ongoing decrease of structure size. Examples are augmenting optical lithography by electron beam direct write strategies and high-throughput imaging of patterned structures with multiple beam electron microscopes. We use multiple beam electron microscopy to image semiconductor wafers processed by electron beam lithography.

A sensitivity analysis (SA) algorithm was developed and tested to comprehend the influences of different test pattern sets on the calibration of a point spread function (PSF) model with complementary approaches. Variance-based SA is the method of choice. It allows attributing the variance of the output of a model to the sum of variance of each input of the model and their correlated factors. 1 The objective of this development is increasing the accuracy of the resolved PSF model in the complementary technique through the optimization of test pattern sets. Inscale® from Aselta Nanographics is used to prepare the various pattern sets and to check the consequences of development. Fraunhofer IPMS-CNT exposed the prepared data and observed those to visualize the link of sensitivities between the PSF parameters and the test pattern. First, the SA can assess the influence of test pattern sets for the determination of PSF parameters, such as which PSF parameter is affected on the employments of certain pattern. Secondly, throughout the evaluation, the SA enhances the precision of PSF through the optimization of test patterns. Finally, the developed algorithm is able to appraise what ranges of proximity effect correction is crucial on which portion of a real application pattern in the electron beam exposure.

Many efforts were spent in the development of EUV technologies, but from a customer point of view EUV is still behind expectations. In parallel since years maskless lithography is included in the ITRS roadmap wherein multi electron beam direct patterning is considered as an alternative or complementary approach for patterning of advanced technology nodes. The process of multi beam exposures can be emulated by single beam technologies available in the field. While variable shape-beam direct writers are already used for niche applications, the integration capability of e-beam direct write at advanced nodes has not been proven, yet. In this study the e-beam lithography was implemented in the BEoL processes of the 28nm SRAM technology. Integrated 300mm wafers with a 28nm back-end of line (BEoL) stack from GLOBALFOUNDRIES, Dresden, were used for the experiments. For the patterning of the Metal layer a Mix and Match concept based on the sequence litho - etch - litho – etch (LELE) was developed and evaluated wherein several exposure fields were blanked out during the optical exposure. E-beam patterning results of BEoL Metal and Via layers are presented using a 50kV VISTEC SB3050DW variable shaped electron beam direct writer at Fraunhofer IPMS-CNT. Etch results are shown and compared to the POR. In summary we demonstrate the integration capability of EBDW into a productive CMOS process flow at the example of the 28nm SRAM technology node.

The usage of phase fluid based stripping agents to remove photoresists from silicon substrates was studied. Photoresists are required for many silicon based technologies such as MEMS patterning, 3D-Integration or frontend and backend of line semiconductor applications [1]. Although the use of resists is very common, their successful integration often depends on the ability to remove the resist after certain processing steps. On the one hand the resist is changing during subsequent process steps that can cause a thermally activated cross-linking which increases the stripping complexity. Resist removal is also challenging after the formation of a hard polymer surface layer during plasma or implant processes which is called skin or crust [2]. On the other hand the choice of stripping chemistry is often limited due to the presence of functional materials such as metals which can be damaged by aggressive stripping chemistries [3].

A new correction technique has been developed not only to reduce the corner rounding, but also to restrain the building up of shot counts that is able to increase the exposure time in electron beam (e-beam) lithography. It is able to prove the developed corner rounding correction technique is useful with high accuracies throughout the simulation of several different types of correction in the data preparation software, Inscale® from Aselta Nanographics, and its comparisons with exposure images. The developed one is helpful to suppress the accumulation of shot counts either. Furthermore, it shows the general limit of corner rounding correction in a conventional variable shaped beam exposure tool with current resist process. Firstly, we are demonstrating the new method for correcting the corner rounding that either can avoid the extension of exposure shot counts, called writing time. Secondly, this study reveals the current bounds of corner rounding correction, especially the lithography employing the shaped beam tool. Finally, we propose the criteria of data preparation for the corner rounding in e-beam lithography, specifically upcoming 18nm technology node and practical applications.

The usage of phasefluid based stripping agents to remove photoresists from silicon substrates was studied. Due to their highly dynamic inner structure phasefluids offer a new working principle, they are penetrating layers through smallest openings and lift off the material from the surface. These non-aggressive stripping fluids were investigated regarding their cleaning efficiency as well as contamination behavior to enable usage in semiconductor and MEMS manufacturing. A general proof of concept for the usage of phasefluids in resist stripping processes is shown on silicon coupons and BKM’s are given for different resist types. In addition a baseline process on 12inch wafers has been developed and characterized in terms of metallic and ionic impurities and defect level.

Proximity Effects in electron beam lithography impact feature dimensions, pattern fidelity and uniformity. These effects are addressed using a mathematical model representing the radial exposure intensity distribution induced by a point electron source, commonly named as the Point Spread Function (PSF). PSF models are usually employed for predicting and compensating for effects up to 15μm. It is well known that there are also some process related phenomena that impact pattern uniformity that have a longer range, namely CMP effects, fogging, etc. Performing proximity effects corrections can result in lengthy run times as file size and pattern densities continue to increase exponentially per technology node. Running corrections for extreme long range phenomena becomes computational and file size prohibitive. Nevertheless, since extreme long range may reach up several millimeters, and new technology nodes require a high level of precision, a strategy for predicting and compensating these phenomena is crucial. In this paper a set of test patterns are presented in order to verify and calibrate the so called extreme long range effects in the electron beam lithography. Moreover, a strategy to compensate for extreme long range effects based on the pattern density is presented. Since the evaluation is based on a density map instead of the actual patterns, the computational effort is feasible. The proposed method may be performed off-line (in contrast to machine standard in-line correction). The advantage of employing off-line compensation relies on enhancing the employ of dose and/or geometry modulation. This strategy also has the advantage of being completely decoupled from other e-beam writer’s internal corrections (like Fogging Effect Correction - FEC).

In electron proximity effects correction (PEC), the quality of a correction is highly dependent on the quality of the model used to compute the effects. Therefore it is of primary importance to have a reliable methodology to extract the parameters and assess the quality of a model. Usually, model calibration procedures consist of one or more cycles of exposure and measurements on the calibration stage. The process and metrology variability may play a key role in the quality of the final model and, hence, of the PEC result. Therefore, it is important to determine at which level these variations may impact a calibration procedure and how a calibration design may be implemented in order to enable more robustness to the resulting model. In this work, metrology variability was evaluated by measuring the same wafer using two different CD-SEM tools. The information coming from these analyses was used as reference to a variation induced calibration test using synthetic data. By inserting variability in synthetic data it was possible to evaluate its impact on the resulting parameter values and in the final model error evaluation.

A dual hard mask concept for high resolution patterning has been evaluated with focus on highly selective etching processes for semiconductor manufacturing. The integration of thin SiO2 and ZrO2 hard mask materials enables highly selective patterning via plasma etch processes for future technology nodes. The patterning sequence is demonstrated for hole arrays with sizes down to 25 nm using a 50 nm thin resist which leads to the fabrication of trenches in silicon with aspect ratios up to 20:1. Alternative ZrO2 based materials were investigated with focus on surface roughness reduction since it influences the final line etch roughness. Here Si-doped ZrO2 (ALD) and spin-coatable ZrO2 were compared to the pure and crystalline ZrO2 as main selective material.

Resist processing for future technology nodes becomes more and more complex. The resist film thickness is getting thinner and hardmask concepts (trilayer) are needed for reproducible etch transfer into the stack. Additional layers between resist and substrate are influencing the electron scattering in e-beam lithography and may also improve sensitivity and resolution. In this study, bare silicon wafers with different assisting underlayers were processed in a 300 mm CMOS manufacturing environment and were exposed on a 50 keV VISTEC SB3050DW variable-shaped electron beam direct writer at Fraunhofer CNT. The underlayers are organic-inorganic hybrid coatings with different metal additives. The negative-tone resist was evaluated in terms of contrast, sensitivity, resolution and LWR/LER as a function of the stack. The interactions between resist and different assisting underlayers on e-beam direct writing will be investigated. These layers could be used to optimize the trade-off among resolution, LWR and sensitivity in future applications.

While significant resources are invested in bringing EUV lithography to the market, multi electron beam direct patterning is still being considered as an alternative or complementary approach for patterning of advanced technology nodes. The possible introduction of direct write technology into an advanced process flow however may lead to new challenges. For example, the impact of high-energy electrons on dielectric materials and devices may lead to changes in the electrical parameters of the circuit compared to parts conventionally exposed by optical lithography. Furthermore, degradation of product reliability may occur. These questions have not yet been clarified in detail. For this study, pre-structured 300mm wafers with a 28nm BEOL stack were dry-exposed at various processing levels using a 50kV variable shaped e-beam direct writer. The electrical parameters of exposed structures were compared to non-exposed structures. The data of line resistance, capacitance, and line to line leakage were found to be within the typical distributions of the standard process. The dielectric breakdown voltages were also comparable between the splits, suggesting no dramatic TDDB performance degradation. With respect to high-k metal gate transistor parameters, a decrease in threshold voltage shift sensitivity was observed as well as a reduced sensitivity to hot carrier injection. More detailed investigations are needed to determine how these findings need to be considered and whether they represent a risk for the introduction of maskless lithography into the process flow of advanced technology nodes.

To fulfill the requirements of future technology nodes new resists with high resolution, high sensitivity and low LWR and LER respectively are needed. A new inorganic non-chemically amplified resist (XE15IB, an experimental resist provided by Inpria Corp.) was investigated. The resist is spin-cast from aqueous solution and is based on hafnium oxide. Metal oxide based resist as XE15IB supersede other resist materials due to its high etch resistance. 1, 2 This new material can be considered as a direct patternable spin on hard mask. XE15IB was processed in a 300mm complementary metal oxide semiconductor (CMOS) manufacturing environment and exposed on a 50 kV VISTEC SB3050DW variable shaped electron beam direct writer at Fraunhofer Center Nanoelectronic Technologies (CNT). The resist was evaluated in terms of contrast, sensitivity and resolution. The process characteristics required for CMOS manufacturing such as delay stability were also examined. Furthermore, by printing a large static random access Memory (SRAM) pattern (design CD of 22 nm), the exposure of a real application pattern was demonstrated.

Using electron beam direct write (EBDW) as a complementary approach together with standard optical lithography at 193nm or EUV wavelength has been proposed only lately and might be a reasonable solution for low volume CMOS manufacturing and special applications as well as design rule restrictions. Here, the high throughput of the optical litho can be combined with the high resolution and the high flexibility of the e-beam by using a mix & match approach (Litho- Etch-Litho-Etch, LELE). Complementary Lithography is mainly driven by special design requirements for unidirectional (1-D gridded) Manhattan type design layouts that enable scaling of advanced logic chips. This requires significant data prep efforts such as layout splitting. In this paper we will show recent results of Complementary Lithography using 193nm immersion generated 50nm lines/space pattern addressing the 32nm logic technology node that were cut with electron beam direct write. Regular lines and space arrays were patterned at GLOBALFOUNDRIES Dresden and have been cut in predefined areas using a VISTEC SB3050DW e-beam direct writer (50KV Variable Shaped Beam) at Fraunhofer Center Nanoelectronic Technologies (CNT), Dresden, as well as on the PML2 tool at IMS Nanofabrication, Vienna. Two types of e-beam resists were used for the cut exposure. Integration issues as well as overlay requirements and performance improvements necessary for this mix & match approach will be discussed.

A new correction approach was developed to improve the process window of electron beam lithography and push its resolution at least one generation further using the same exposure tool. An efficient combination of dose and geometry modulation is implemented in the commercial data preparation software, called Inscale®, from Aselta Nanographics. Furthermore, the electron Resolution Improvement Feature (eRIF) is tested, which is based on the dose modulation and multiple-pass exposure, for not only overcoming the narrow resist process windows and disability of exposure tool but also more accurate correction of exposure data in the application of sub-35nm regime. Firstly, we are demonstrating the newly developed correction method through the comparison of its test exposure and the one with conventional dose modulation method. Secondly, the electron Resolution Improvement Feature is presented with the test application for complementary exposure and with the application of real design, specifically for sub-30nm nodes. Finally, we discuss the requirements of data preparation for the practical applications in e-beam lithography, especially for future technology nodes.

For the manufacturing of semiconductor technologies following the ITRS roadmap, we will face the nodes well below 32nm half pitch in the next 2~3 years. Despite being able to achieve the required resolution, which is now possible with electron beam direct write variable shaped beam (EBDW VSB) equipment and resists, it becomes critical to precisely reproduce dense line space patterns onto a wafer. This exposed pattern must meet the targets from the layout in both dimensions (horizontally and vertically). For instance, the end of a line must be printed in its entire length to allow a later placed contact to be able to land on it. Up to now, the control of printed patterns such as line ends is achieved by a proximity effect correction (PEC) which is mostly based on a dose modulation. This investigation of the line end shortening (LES) includes multiple novel approaches, also containing an additional geometrical correction, to push the limits of the available data preparation algorithms and the measurement. The designed LES test patterns, which aim to characterize the status of LES in a quick and easy way, were exposed and measured at Fraunhofer Center Nanoelectronic Technologies (CNT) using its state of the art electron beam direct writer and CD-SEM. Simulation and exposure results with the novel LES correction algorithms applied to the test pattern and a large production like pattern in the range of our target CDs in dense line space features smaller than 40nm will be shown.

For the manufacturing of semiconductor technologies following the ITRS roadmap, we will face the nodes well below 32nm half pitch in the next 2~3 years. Despite being able to achieve the required resolution, which is now possible with electron beam direct write variable shaped beam (EBDW VSB) equipment and resists, it becomes critical to precisely reproduce dense line space patterns onto a wafer. This exposed pattern must meet the targets from the layout in both dimensions (horizontally and vertically). For instance, the end of a line must be printed in its entire length to allow a later placed contact to be able to land on it. Up to now, the control of printed patterns such as line ends is achieved by a proximity effect correction (PEC) which is mostly based on a dose modulation. This investigation of the line end shortening (LES) includes multiple novel approaches, also containing an additional geometrical correction, to push the limits of the available data preparation algorithms and the measurement. The designed LES test patterns, which aim to characterize the status of LES in a quick and easy way, were exposed and measured at Fraunhofer Center Nanoelectronic Technologies (CNT) using its state of the art electron beam direct writer and CD-SEM. Simulation and exposure results with the novel LES correction algorithms applied to the test pattern and a large production like pattern in the range of our target CDs in dense line space features smaller than 40nm will be shown.

For shortening the writing time, especially in shaped Electron Beam Direct Writing (EBDW), it is crucial to reduce the number of shapes and the coverage of layout for exposure. The determination of conventional or reversed image printing according to the process integration is one of the concerns for time and cost-effective process in the EBDW. We have studied two different cases for the purpose above. First, the proximity effect correction (PEC) with dose modification applied on each tone of resists, positive and negative, for the printing of conventional and reversed images. The CDs that are obtained from the both printed images compared and are either with that from the simulations. Secondly, the two different types of PEC, dose and shape modification, applied to a conventional image using an identical point spread function (PSF). The line edge roughness (LER), line width roughness (LWR) and CDs in dose and shape corrected conventional image pattern have been measured and compared. The MGS/PROXECCO was used for all the preparation of exposure data mentioned above. In summary, we suggest the strategies of efficient PEC for the EBDW of contrasting images, propose the available method of PEC for the time-efficient EBDW, and for the further multiple EBDW developments.

In electron beam lithography, the electron scattering and the corresponding proximity effect highly influence the feature resolution. Especially for sub-100 nm features a compensation for this effect is needed. There are several methods of determination of the proximity parameters, which mostly are time-consuming and complex due to a need of an initial proximity effect correction and immense measurement effort. In this paper the checkerboard pattern is proposed to provide the opportunity for proximity parameter determination in a fast and easy manner without using a sophisticated CD-SEM metrology. The concept is illustrated by simulation and first experimental results are shown.

Projection Mask-Less Lithography (PML2) is a potentially cost-effective multi electron-beam solution for the 22 nm half-pitch node and beyond. PML2 is targeted on using hundreds of thousands of individually addressable electron-beams working in parallel, thereby pushing the potential throughput into the wafers per hour regime. With resolution potential of < 10 nm, PML2 is designed to meet the requirements of several upcoming tool generations.

Electron beam direct write (EBDW) can be utilized for developing metrology methods for future technology nodes. Due to its advantage of high resolution and flexibility combined with suitable throughput capability, variable-shaped E-Beam lithography is the appropriate method to fabricate sub 40nm resist structures with accurately defined properties, such as critical dimension (CD), pitch, line edge roughness (LER) and line width roughness (LWR). In this study we present results of exposure experiments intended to serve as an important instrument for testing and fitting various metrology and defect density measurement methods for future technology nodes. We successfully fabricated sub 40nm gratings with varying CD, pitch, programmed defects and LER/LWR. First metrology measurements by means of optical scatterometry on these dense structures show that variation of the signal response is sufficient to detect sub 10nm fluctuations with a satisfying repeatability.

Because of mask cost reduction, electron beam direct write (EBDW) is implemented for special applications such as rapid prototyping or small volume production in semiconductor industry. One of the most promising applications for EBDW is design verification by means of metal fix. Due to write time constrains, Mix & Match solutions have to be developed at smaller nodes. This study reports on several Mix and Match processes for the integration of E-Beam lithography into the optical litho process flow of Qimonda's 70 nm and 58 nm DRAM nodes. Different metal layers have been patterned in part with DUV litho followed by E-Beam litho using a 50 kV Vistec SB3050 shaped electron beam direct writer. All hardmask patterns were then simultaneously transferred into the DRAM stack. After full chip processing a yield study comprising electrical device characterization and defect investigation was performed. We show detailed results including CD and OVL as well as improvements of the alignment mark recognition. The yield of the E-Beam processed chips was found to be within the range of wafer-to-wafer fluctuation of the POR hardware. We also report on metal fix by electrical cutting of selected diodes in large chip scales which usually cannot be accessed with FIB methods. In summary, we show the capability of EBDW for quick and flexible design verification.

The resolution of a variable shaped beam writer is typically given for the standard geometries like isolated line, isolated space, and dense (1:1) line/space pattern. It is related to the imaging power of both the tool itself as well as the resist process. In this paper we concentrate on small shots with dimensions smaller than the resolution limit, butting to a larger shot. We show experimentally that for a line resolution of 40 nm the resolution for butting sub resolution shots can be as small as 20 nm.

Line edge roughness (LER) and line width roughness (LWR) have raised questions and concerns as current lithography techniques reduce critical dimensions (CD) below 50 nm. There are few applications of controlled variation of LER and LWR, even among those which use electron beam direct writing (EBDW), although it is highly desirable to test the influence of systematical variation of LER and LWR on actual semiconductor devices. To get a clear understanding how and what the LERs and LWRs are influencing in EBDW, we have designed and fabricated transistor gates with programmed LER and LWR using EBDW and observed those based on CD-SEM metrology. The obtained results including calculated power spectrum density (PSD) shows the capability of EBDW to control the LER/LWR. Further, the influence of edge/width roughness in EBDW on device characteristics is reviewed and it gives how the effect of LWR/LER translates to device performance in DRAM process flow. It is found that the control of LWR is more important than that of LER for future lithography developments.

For Electron Beam Direct Write (EBDW) a systematic investigation of defect density using a Negevtech 3100 darkfield inspection system was performed. A special defect learning pattern for memory applications with coverage of 50% was designed and printed partially on 300mm wafers using chemically amplified positive and negative E-Beam resists. By optical defect measurements post litho it was possible to inspect 50nm dense lines to characterize the exposure system as well as the used resist process. Using this method a large exposed area in millimeter range can be inspected and an overview on exposure quality can be gained in a reasonable amount of time. Particle measurements were performed additionally to distinguish between particles and exposure issues. By using darkfield measurements, process related issues like development problems and resist residuals can be found, as well as writing issues like shot butting and write field stitching can be quickly determined and controlled with this method. In this paper, the measurement methodology is described as well as the effect of writer imperfections on the darkfield images. A pareto analysis is performed and shows the frequency of occurrence of different defects. Measures to reduce defects - especially on the tool side - are given. The method is feasible to use in a regular check to control tool and process performance.

E-beam direct writing, one node ahead of advanced optical lithography, can be a time and cost effective option for early device and technology development as well as for fast prototyping. Because of the device complexity only a variable-shaped e-beam writer combined with sensitive chemically amplified resists (CAR) can be considered for this approach. We evaluated various pCARs and nCARs of all major suppliers for our goal to structure DRAMs of the 50nm node using the Leica SB350 e-beam writer. The most promising samples were selected for a process optimization by variation of bake and development conditions. Finally, one resist of each tonality met the most of our specifications like dense lines and contact holes resolution, sensitivity and vacuum stability.

A detailed account will be given of work done on the Micrascan VII (NA 0.75) at INVENT in Albany with AZ EXP X20 and AZ EXP X25 resist systems based upon BOCME protected fluoroalcohol resins. These resins were examined either with a high or low level of formulated photoacid generator (PAG). Our evaluations done both with binary and alternating phase shift mask exposures. It was found in our initial studies done at relatively high amine levels (1-2 ppb) that AZ EXP X25 X with low PAG gave the best performance.

We summarize our work on devising protective barrier coats for use against airborne contamination when using tert-butoxycarbonylmethyl (BOCME) capped fluoroalcohol resist resins as part of our strategy to develop a 157 nm resist platform. We will describe how a barrier coat (AZ® EXP FX Coating 145) consisting of a fluoroc-yclopolymer formulation, soluble in aqueous developer, can improve the post-exposure delay (PED) latitude of 157 nm resist resists exposed under conditions or airborne contamination. Specifically, a 20 nm thick coating of AZ® EXP FX Coating 145 gives a PED latitude for L/S features of at least 10 min under condition of airborne amine contamination (10 ppb amine contamination). The barrier coat, AZ® EXP FX coating 145 is formulated in a solvent which is compatible with resist film coated from typical 193 nm resist spin casting solvents. Moreover, it can be easily removed as part of the normal aqueous base development scheme, no extra post-apply bake or stripping step is required.

This paper is part of our continuing work on a new generation of more transparent, 157 nm resist platforms, which are based upon capping of fluoroalcohol-substituted, transparent perfluorinated resins (TFR) with a tert-butoxycarbonylmethyl (BOCME) moiety. Recent results indicate that by optimizing both resin structure and loading of photoacid generator and base additive a good compromise can be achieved between resolution power, dark erosion resistance, sensitivity and transparency at 157 nm. Specifically, it was found that a decrease in PAG (50% nominal loading) and base loading (75% nominal loading), coupled with optimization of the TFR resins to achieve higher transparency, gives the best compromise of properties. In this manner, resist systems with a transparency as low as 0.87 AU/micron were designed capable of resolving 60 nm 1:1 features, at a dose of 92 mJ/cm 2 (non corrected for sigma), using a strong phase shift mask, and a sigma of 0.3 on a Exitech 157 nm small field mini-stepper. This type of resist material has also been imaged with a larger field tool ( DUV30 Micrascan VII ) to give 80 nm 1.1.5 L/S features at a dose of 135 mJ/cm 2 employing using a Binary mask (σ=0.85). Finally, it was found that our BOCME-TFR based resist system can be used to transfer a 120 nm L/S pattern (imaged by 193 nm lithography) into a hardmask stack on top of silicon.

Several fluoro-substituted polymers consisting of acid cleavable methacryoic or cinnamic acid tert.-butyl ester compounds copolymerized with maleic acid anhydride derivatives were synthesized by radical copolymerization. Vacuum ultraviolet transmission measurements of the samples reveal absorbances down to 5micrometers -1 despite of the strongly absorbing anhydride moiety which serves as silylation anchor for the application of the Chemical Amplification of Resist Lines (CARL) process, one of the promising approaches for sub-90nm pattern fabrication. Some of the samples exhibit resolutions down to 110nm dense at 157nm exposure using an alternating phase shift mask. The feasibility of the CARL principle including the silylation reaction after development has been demonstrated with selected fluorinated polymer samples.

SUMMARY Thin film imaging is a possible solution for 157 nm and other NGL techniques in lithography due to DOF problems,absorbance and possible pattern collapse in thick resist films at line widths below 90 nm. We have modified the CARLbilayer process consisting of a thin imaging top resist with the option of silylation and a thick Novolac bottom resist tothe 157 nm wavelength. This work is part of the German BMBF project ,,Laserbasierte Ultraprazisionstechnik - 157 nm-Lithographie".We used a silicon free top resist (Si free CARL) for the CARL bilayer resist process to avoid silicon outgassing andirreversible contamination of the tool optics at 1 57 nm. The top resist polymer is a base polymer for our ongoing workof fluorination and therefore for resists with a higher transparency at 1 57 nm. In the first imaging experiments a film thickness of ca. 50 nm was applied. The silylation step between wet development of the imaging top resist and dry development of the bottom resist provides a high etch resistance in the final plasma process. A high silicon content inthe structures obtained by this treatment allows a structuring of up to 300 nm bottom resist with ultra-thin films of theimaging top resist (< 50 nm). The Novolac or PHS based bottom resist provides high etch resistance also for aggressivesubstrate etch processes.

Most photorefractive (PR) materials require plasticizers in order to decrease the glass transition temperature, allowing for orientational enhancement by the chromophores. Introduction of the plasticizer, however, alters not only the viscosity but also the photoconductive properties of the material. This can be shown by comparing two different plasticizers which were introduced into a bifunctional low-molecular-weight PR glass and into a polyfluorene guest-host polymer. The latter reaches response times down to 600 microsecond(s) at a writing intensity of 1 W/cm2. We have recently improved the concept of low-molecular-weight PR glasses. A suitable, photoconducting unit allows the synthesis of a bifunctional system with a glass transition of 22.6 degree(s)C. Therefore, no plasticizer is needed. The material is based on a triphenyldiamine (TPD) moiety to which a nonlinear-optical chromophore is directly attached. The system is the first representative of a whole class of TPD molecules and polymers for photorefractive applications.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We report on holographic investigations of several organic photorefractive materials based on monolithic low molar mass glasses. The addition of different plasticizing agents and the variation of three NLO-units prove to change the photorefractive performance and the thermal properties of the resulting compounds dramatically. Very fast holographic response times down to 2.5 ms could be reached at refractive index modulations of 6 10- and two-beam coupling gains of up to 140 cm-1.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A series of novel bifunctional cyclosiloxanes with pendant photoconducting and nonlinear-optical moieties was synthesized in a two step procedure. The variation of the spacer length between the siloxane ring and the functional carbazole and azo moieties leads to glass transition temperatures between 33 degrees C and 61 degrees C. These well defined low-molar mass compounds are characterized with regard to their chemical, thermal and electrooptical properties. Compared to commonly used guest-host systems crystallization of the chromophore dopants is diminished due to the covalent bonding of the azo-dye to the cyclosiloxane backbone.

We present an organic photorefractive material based on a low molar mass glass with both photoconductive and nonlinear optical properties. By implementing a novel plasticizer and doping with the well known sensitizer C60 weobtained a composite material, which shows extremely fast initial response times of 2.5 ms at writing beam intensitiesof 'write 1 W/cm2 and 450 is at 'write 10.8 W/cm2. Combined with high refractive index modulations of up toLrt = 6 . iO and sample lifetimes of over 6 months this material exhibits an excellent overall performance.In comparison to another similar composite system which was plasticized by a more polar dopand, we demonstratethe crucial role of this functionality in the dispersivity of charge transport and the photorefractive grating dynamics. The complicated temporal behavior of grating build-up and decay which was investigated by degenerate four-wavemixing experiments is discussed in detail. We propose a new way to describe these processes in a more generalmanner as it is done up to date, using an inverse Laplace transform (ILT) analysis.Keywords: photorefractive glass, photoconductivity, time-of-flight, response time, dispersive charge transport

Seven novel photorefractive glasses have been prepared in an effective four-step synthesis. The low molar mass glasses consist of a triphenylamine-core substituted with two carbazole moieties and a NLO-chromophore (NLO-DCTAs). In a second series of compounds (NLO-DATAs) the carbazole groups are replaced by diphenylamine. The compounds from stable glasses with Tgs of about 120 degrees C and 85 degrees C. The photorefractive properties such as the diffraction efficiency (eta) , the modulation amplitude of the refractive index (Delta) n, and the gain coefficient (Gamma) were determined by means of degenerate four-wave mixing and two- beam coupling experiments. We observed diffraction efficiencies of (eta) equals 90 cm-1. The samples have excellent properties with respect to optical quality and shelf-lifetime.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We investigated polymeric materials based on polysiloxane (PSX), polymethylmethacrylate (PMMA), polyurethane (PU), as well as a triphenylamin-based glass (DRDCTA) with respect to their photorefractive properties. Electric-field dependencies of the two-beam coupling gain, diffraction efficiencies, refractive index amplitudes and holographic rise-times could be obtained by means of two-wave mixing and degenerate four-wave mixing measurements. The examined PSX polymer systems were composed of a photoconducting polysiloxane host doped with trinitrofluorenone (TNF) as a sensitizing moiety and various chromophores, namely, an azo derivative, a stilben derivative and a tolan derivative. Due to their comparatively low glass-transition temperatures T g , an orientational enhancement of the photorefractive properties was observed. Furthermore, the influence of photoisomerisation (based on trans-cis-trans cycles) on the holographical properties could be determined for the different chromophores. In addition, a class of fully functionalized polymers with azo chromophores and carbazole-units covalently attached to PMMA- and PU-backbones was synthesized. These systems show comparatively high glass transition temperatures of more than 80 degrees C. The third type of materials investigated is a glass of triphenylamin with attached carbazole and NLO-chromophore moieties. It has a glass transition temperature of 120 degrees C. For the high-T g materials, poling procedures--essential for the photorefractive properties--could be monitored in-situ by second-harmonic generation. Absolute values for the nonlinear Pockets coefficients χ (2) (-ω; ω, 0) have been obtained by electro-optical measurements.

In this paper we report on the synthesis of a number of photorefractive materials with high glass transition temperatures. We have developed a series of fully-functionalized polymethacrylates with both photoconducting and NLO-active moieties. Secondly, low molecular weight glasses based on triphenylamine and carbazole units together with different NLO-chromophores have been designed which show no tendency towards crystallization. We now report on the synthetic approach to these novel materials and their properties with regard to photorefractive applications.

The development of devices that are based on MEMS-on-CMOS technology becomes increasingly time-consuming since System-on-a-Chip (SoC) solutions for highly integrated and miniaturized devices are approaching smaller feature sizes. In order to reduce the development costs and shorten the time-to-market periods, the combination of commercially available CMOS processes from foundries with the subsequent processing in a dedicated MEMS facility is beneficial. This concept offers the possibility to separate the different technological requirements of conventional CMOS manufacturing and MEMS actor processing, which may follow different design rules and process specifications. As a representative of the dedicated MEMS foundries, Fraunhofer IPMS performs surface micromachining on 200 mm wafers for a variety of MEMS devices, in particular for spatial light modulators (SLM). Over the past decade, much experience was gained in development activities for customer specific applications like micro mirror arrays. In this paper, we will discuss essential requirements and upcoming challenges for the monolithic integration of surface micro-machined optical MEMS on foundry-fabricated CMOS backplanes, as conventional (i-Line) lithography is approaching patterning limits. We will present approaches of tuning the planarization of the CMOS chip surface to achieve an excellent mirror array flatness with CMOS compatible inorganic sacrificial layer techniques. Concepts like Mix&Match lithography for achieving high overlay accuracy and the litho stitching technique for the patterning of large chips will be reviewed and a brief outline of our roadmap for the implementation of DUV lithography will be presented.