Search

We have been studying the application of ion implantation technology to power semiconductors. The ion implantation technology uses a stencil mask instead of a photo-resist mask in order to reduce the number of processes and achieve high-energy mask ion implantation. Deterioration in implantation pattern accuracy, which is caused by thermal deformation of the stencil mask due to ion beam incidence, has become a critical issue because of the heavy use of high doses of ion implantation in the power semiconductor. In this research, we developed a stencil mask structure that drastically reduces thermal deformation, and technology capable of realizing the ring pattern needed in power semiconductors. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Implant angle control is increasingly important with each new device node. Some devices have demonstrated a sensitivity of threshold voltage of about 100 mV/deg for implant angle and require implant angles to be held within +/- 0.2° for process control. There are many sources of angle variation in single wafer implanters. Mechanical orientation can usually be controlled to high precision, but an accurate control of the implant angle requires knowledge of the actual beam angle relative to the surface or crystal planes of the wafer. In-situ methods to measure beam angles in both the horizontal and vertical planes are required and it is necessary that these methods be calibrated to the surface or crystal planes of the wafer to achieve the required angle control. Optima MD has incorporated methods to automatically measure beam angles prior to implant in both planes, and correct for any deviation from the desired implant angle. The symmetric parallelizing lens that corrects angles without bending the beam enables a method of calibrating the horizontal angle mask to crystal planes with one or two wafers. This paper discusses the methods of measurement, calibration, and accuracy of the Optima MD angle control system. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The secure optical memory system based on a double-random phase-encoding optical encryption system is proposed. The quality of decrypted data can be improved by designing an input phase mask to utilize the bandwidth the bandwidth of the optical system effectively. We propose the certification method of the data recorded into the optical memory by using a designed input phase mask as a phase code. Computer simulations confirm the possibility of the proposed certification system. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Lithography is one of the most important semiconductor micro-fabrication technologies that form mask pattern images onto the substrate. Since a mask is the original edition of semiconductor patterns, precise control of the mask aperture size becomes critical. The masks have to be made up in the accurately controlled patterns and zero defects. Therefore, mask inspection and metrology that guarantee the mask qualities are important key technologies for realizing the semiconductor production with high reliability and high yield. The advanced inspection and metrology are being developed. The requirements, technical issues, and current status of these technologies are reported. Mask inspection technologies for next generation lithography such as electron projection lithography (EPL) and extreme ultraviolet lithography (EUVL) are also reported. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

Extreme Ultraviolet (EUV) lithography is under development to succeed 157nm lithography for commercial IC manufacturing for the 45nm technology node as defined by the ITRS 2001 Lithography Roadmap. EUV masks pose many manufacturing and technical challenges to meet the future commercial needs. Although some EUV mask manufacturing processes can be extended from current optical masks, many new issues arise due to transitioning to all reflective multi-layer mirror system with patterned features versus conventional optical masks. EUV lithography operation at 13.4 – 13.5 nm wavelength requires optimal multi-layer performance including peak reflectance, wavelength matching to the optical system, and very low defect levels. The Low Thermal Expansion Material (LTEM) that is used as a substrate for the multi-layer reflector also requires demanding performance levels including Coefficient of Thermal Expansion (CTE), flatness, and roughness to support EUV mask needs. Performance improvements as large as several orders of magnitude are needed for some of these parameters. To aid these developments, specialized metrology tools are needed. These tools fall into two categories: Manufacturing process inspections tools include flatness interferometry, atomic force microscopy, EUV reflectometry, defect inspection, and others. Analytical tools include scanning electron microscopy, X-Ray Diffraction, ion beam milling, and others used for problem solving. Both metrology types will play a major role in the successful development of EUV masks to meet the 45nm node requirements. This paper will review many applicable metrology techniques in addition to those listed, describe the application to EUV mask blank development or manufacturing, show problem solving examples of the techniques, and highlight particular problems or areas of need. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

The application of high pressure or environmental microscopy techniques is not new to scanning electron microscopy. However, application of this methodology to semiconductor metrology is new because of the combined need for implementation of high resolution, high brightness field emission technology in conjunction with large chamber and sample transfer capabilities. This methodology employs a gaseous environment to help neutralize the charge build-up that occurs under irradiation with the electron beam. Although potentially very desirable for the charge neutralization, this methodology has not been seriously employed in photomask or wafer metrology until now. This is a new application of this technology to this area, but it shows great promise in the inspection, imaging and metrology of photomasks in a charge-free operational mode. For accurate metrology, this methodology affords a path that minimizes, if not eliminates, the need for charge modeling. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

The SPI Imaging Test Setup (SPITS) was built at MPE to allow experimental verification of the imaging properties of the SPectrometer onboard INTEGRAL (SPI). Of special importance is the possibility to validate simulations -- which are needed for SPI image reconstruction -- with laboratory measurements. SPITS consists of a coded mask and two Germanium detectors. The coded mask has the same tungsten-alloy HURA mask coding as SPI and is made of SPI flight model materials. The two hexagonal Ge-detectors are from the SPI flight detector manufacturing line. Housed in a common A1 vacuum cap and mounted on an XY-table, they can be moved to cover the 19 Ge detector positions of the SPI camera. We have measured the response of SPITS to radioactive sources (60 keV to 1.8 MeV) at a distance of 9 m from the detector plane. We use both image deconvolution algorithms foreseen for SPI data analysis (spiros and spiskymax) for our analysis. We present our findings for the angular resolution and the point-source-location capability of SPITS for several photon energies and for several source geometries relative to the mask coding. [ABSTRACT FROM AUTHOR]

It is a well-known fact that the high-energy gamma-ray telescopes in conventional designs are inherently limited in their spatial resolving powers. EGRET can locate a point source to 5 to 10 arcmin accuracy, while GLAST can achieve source location capabilities to better than 0.5 arcmin. Although there is still room for improvement in the angular resolution of the conventional high-energy gamma-ray telescopes, other means can also be explored at this time. Coded masks have been successfully used for X-ray and low-energy gamma-ray telescopes. Such devices have also been considered for high-energy gamma-ray telescopes from time to time. In this paper we investigate the feasibility of using coded masks to achieve much higher source location capabilities for a high-energy gamma-ray space telescope. We discuss the merits and the difficulties of using coded masks to achieve this goal. In particular, we look into the issues of size, weight, field of view, and the trade-off between the angular resolution and the field of view for such coded masks. [ABSTRACT FROM AUTHOR]