Electron-based diagnostics at the National Ignition Facility use Sandia’s Icarus sensors for ultrafast imaging. However, the electron detection performance of these sensors has remained mostly unknown. Previous work characterized the singulated Common Anode photodiode structure of the ”Furi” and ”Hippogriff” but did not include the Common Cathode photodiode structure of the Icarus. Using a fully fabricated Icarus sensor, we measured the cross-sectional geometries and modeled the expected performance; then, we measured the sensor’s EQE, quantum yield, and charge gain with an electron gun. These measurements were essential to understanding the space-charge limitations of the electron-based diagnostics that use them.
X-ray Diodes (XRDs) are currently used for spectroscopic measurements, measuring X-ray flux, and estimating spectral shape of the VUV to soft X-ray spectrum. A niche exists for an inexpensive, robust X-ray diode that can be used for experiments in hostile environments on multiple platforms, including explosively driven experiments that have the potential for destroying the diode during the experiment. A multiple channel stacked filtered array was developed with a small field of view where a wider parallel array could not be used, but filtered channels for energies lower than 1000 eV were too fragile to deploy under normal conditions. To achieve both the robustness and the required low-energy detection ability, we designed a small low-energy mirrored channel with a spectral sensitivity from 30 to 1000 eV. The stacked MiniXRD X-ray diode system design incorporates the mirrored low-energy channel on the front of the stacked filtered channels to allow the system to work within a small field of view. We will present results that demonstrate this is a promising solution for low-energy spectrum measurements.
There are many types of X-ray diodes that are used for X-ray flux or spectroscopic measurements and for estimating the spectral shape of the VUV to soft X-ray spectrum. However, a need arose for a low cost, robust X-ray diode to use for experiments in hostile environments on multiple platforms, and for experiments that utilize forces that may destroy the diode(s). Since the typical proposed use required a small size with a minimal single line-of-sight, a parallel array could not be used. So, a stacked, filtered multi-channel X-ray diode array was developed, called the MiniXRD. To achieve significant cost savings while maintaining robustness and ease of field setup, repair, and replacement, we designed the system to be modular. The filters were manufactured in-house and cover the range from 450 eV to 5000 eV. To achieve the line-of-sight accuracy needed, we developed mounts and laser alignment techniques. We modeled and tested elements of the diode design at NSTec Livermore Operations (NSTec / LO) to determine temporal response and dynamic range, leading to diode shape and circuitry changes to optimize impedance and charge storage. We fielded individual and stacked systems at several national facilities as ancillary ‘ride-along’ diagnostics to test and improve the design usability. We present the MiniXRD system performance which supports consideration as a viable low-cost alternative for multiple-channel low-energy X-ray measurements. This diode array is currently at Technical Readiness Level (TRL) 6.
Step and Flash Imprint Lithography (S-FIL) is an attractive method for printing sub-100 nm geometries. Relative to other imprinting processes S-FIL has the advantage that the template is transparent, thereby facilitating conventional overlay techniques. Previous work on S-FIL templates has focused on a chromium and quartz pattern transfer process that is compatible with processes that are currently used in mask shops. It is likely that 1X templates will require electron beam inspection, however, and templates that include buried charge conduction layers may be required. The purpose of this work was to investigate the issues associated with fabricating and inspecting these types of templates. The patterning stack examined included a layer of ZEP520A positive electron beam resist, followed by thin layers of chromium, silicon oxynitride, and indium tin oxide. The chromium layer was needed to avoid laser height sensor problems encountered prior to electron beam exposure. The pattern transfer process was characterized, and CD uniformity was characterized in four quadrants of the photoplate. A prototype electron beam inspection system was then used to inspect an array of programmed defect patterns. Two methods for fabricating templates were considered.
Over the past several years, advanced photolithography has moved from 0.35 micrometers technology to 0.25 micrometers as the standard. Soon the technology will move into the 0.18 micrometers generation. Due to the ever-shrinking feature sizes on advanced photolithographic masks, phase shifting technology has been incorporated to improve resolution on the exposed wafer. On such masks the minimum phase error and the maximum percent transmission must be dealt with. These requirements have challenged the ability to repair masks with opaque and clear defects. The Micrion focused ion beam system currently repairs opaque defects found on advanced phase shifting chrome and molybdenum silicide masks. In this paper, Micrion discusses advanced repair techniques and strategies used to address the stringent requirements of matching phase and percent transmission at the repaired defect sites. Difficulties in opaque defect and clear defect repair strategies will be discussed.
This paper addresses the capabilities of the Micrion 8000 FIB (focused ion beam) phase shift mask repair tool to repair clear defects and opaque defects found on chrome-based binary and attenuated phase shift masks, and MoSi-based attenuated phase shift masks for 0.35 micrometer lithography. For a repair to be successful, the repair must: match size, shape, and position of the defect, reproduce the desired transmission, minimize damage to the underlying substrate, minimize damage to surrounding non-defect areas, and finally, the repair must be durable. For the production environment, a repair tool must be very reliable and easy to use as well. The Micrion 8000 FIB phase shift mask repair tool incorporates the above requirements.
The characteristics of an ideally repaired opaque defect on a molybdenum silicide (MoSiaObNc) photomask are: (1) the total removal of the MoSiaObNc defect, leaving no residual MoSiaObNc; (2) a smooth, level quartz surface (no over-etch) after the MoSiaObNc is removed; (3) minimal riverbedding of the quartz at the perimeter of the MoSiaObNc defect; and (4) maximum light transmission (%T) at the i-line (365 nm) and DUV (248 nm) lithographic wavelengths. Achieving these ideal repair characteristics is becoming increasingly difficult as the patterned features become smaller, as the lithographic wavelength becomes shorter and as phase shifting mechanisms are implemented. A chemical process has been developed to enhance the FIB (focused ion beam) etching of MoSiaObNc defects. Using this chemical process, a FIB protocol has been developed which enhances the removal of a MoSiaObNc defect while inhibiting the removal of quartz. AFM (atomic force microscopy) indicates that (1) MoSiaObNc is totally removed, (2) the quartz remains smooth and level (no over-etch), and (3) the riverbends are, at this time, 10 - 45 nm; our target is 1 - 15 nm. The MoSiaObNc etch process reduces optical staining due to implanted gallium
On the standard Micrion 8000 PM Repair System platform, the repair accuracy for clear defect repair and opaque defect repair is plus or minus 75 nm. Incorporation of a new ion beam column has pushed the repair accuracy for clear and opaque defect repairs to smaller values. This new system can image isolated defects less than 200 nm in size. To characterize the repair accuracy of the system, experiments on edge placement accuracy were performed. This paper presents data on the accuracy of defect repairs using the Micrion 8000 PSM Repair System on Chrome masks. The study specifically looks at the edge placement of opaque defect and clear defect repairs on masks coated with a conductive layer versus masks not coated with a conductive layer. We also explore the edge placement accuracy of the repair due to the directionality of the repair scan. Finally we examine the shape of the distribution function of the repair measurements and also investigate differences in the measured edge placement accuracy of repairs using different measuring techniques.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.