Showing papers on "Illumination angle published in 2002"

Understanding the forbidden pitch and assist feature placement

Abstract: Optical proximity effect is a well-known phenomenon in photolithography. Such an effect results from the structural interaction between the main feature and the neighboring features. Recent observations have shown that such structural interactions not only affect the critical dimension of the main feature at the image plane, but also the exposure latitude of the main feature. In this paper, it has been shown that the variation of the critical dimension as well as the exposure latitude of the main feature is a direct consequence of light field interference between the main feature and the neighboring features. Depending on the phase of the field produced by the neighboring features, the main feature critical dimension and exposure latitude can be improved by constructive light field interference, or degraded by destructive light field interference. The phase of the field produced by the neighboring features can be shown to be in the location where the field produced by the neighboring features can be shown to be dependent on the pitch as well as the illumination angle. For a given illumination, the forbidden pitch lies in the location where the field produced by the neighboring features interferes with the field of the main feature destructively. The theoretical analysis given here offers the tool to map out the forbidden pitch locations for any feature size and illumination conditions. More importantly, it provides the theoretical ground for illumination design in order to suppress the forbidden pitch phenomenon, and for scattering bar placement to achieve optimal performance as well.

Method of identifying an extreme interaction pitch region, methods of designing mask patterns and manufacturing masks, device manufacturing methods and computer programs

Abstract: Optical proximity effects (OPEs) are a well-known phenomenon in photolithography. OPEs result from the structural interaction between the main feature and neighboring features. It has been determined by the present inventors that such structural interactions not only affect the critical dimension of the main feature at the image plane, but also the process latitude of the main feature. Moreover, it has been determined that the variation of the critical dimension as well as the process latitude of the main feature is a direct consequence of light field interference between the main feature and the neighboring features. Depending on the phase of the field produced by the neighboring features, the main feature critical dimension and process latitude can be improved by constructive light field interference, or degraded by destructive light field interference. The phase of the field produced by the neighboring features is dependent on the pitch as well as the illumination angle. For a given illumination, the forbidden pitch region is the location where the field produced by the neighboring features interferes with the field of the main feature destructively. The present invention provides a method for determining and eliminating the forbidden pitch region for any feature size and illumination condition. Moreover, it provides a method for performing illumination design in order to suppress the forbidden pitch phenomena, and for optimal placement of scattering bar assist features.

Synthesis of artificial magnetic conductors by using multilayered frequency selective surfaces

Abstract: In this letter, the combination of a multilayered dielectric structure, a capacitive frequency selective surface (FSS) and a perfectly electric conducting (PEC) ground plane is proposed for realizing high-impedance surfaces. These surfaces behave like an artificial magnetic conductor (AMC) in a specific frequency range; the inclusion of the dielectric layers allows us to enhance the angular properties of the AMC as well as the frequency bandwidth of the device. In order to obtain the proper values of the design parameters, a genetic algorithm (GA) is employed that makes use of an electromagnetic solver based on the method of moments (MoM) to evaluate the scattering properties of the structure. A key step in the design procedure is the inclusion in the fitness function of the electromagnetic response of the high-impedance surface with respect to the illumination angle. The synthesized structure shows the desired frequency performance and reveals robust as concerns the stability of the solution with respect to a wide interval of illumination angles.

Understanding the forbidden pitch phenomenon and assist feature placement

Abstract: Optical proximity effect is a well-known phenomenon in photolithography. Such an effect results from the structural interaction between the main feature and the neighboring features. Recent observations have shown that such structural interactions not only affect the critical dimension of the main feature at the image plane, but also the exposure latitude of the main feature. In this paper, it has been shown that the variation of the critical dimension as well as the exposure latitude of the main feature is a direct consequence of light field interference between the main feature and the neighboring features. Depending on the phase of the field produced by the neighboring features, the main feature exposure latitude can be improved by constructive light field interference, or degraded by destructive light field interference. The phase of the field produced by the neighboring features can be shown to be dependent on the pitch as well as the illumination angle. For a given illumination, the forbidden pitch lies in the location where the field produced by the neighboring features interferes with the field of the main feature destructively. The theoretical analysis given here offers the tool to map out the forbidden pitch locations for any feature size and illumination conditions. More importantly, it provides the theoretical ground for illumination design in order to suppress the forbidden pitch phenomenon, and for scattering bar placement to achieve optimal performance as well.

Monostatic and bistatic statistical shadowing functions from a one-dimensional stationary randomly rough surface according to the observation length: I. Single scattering

Abstract: When solving electromagnetic rough-surface scattering problems, the effect of shadowing by the surface roughness often needs to be considered, especially as the illumination angle approaches grazing incidence. This paper presents the Ricciardi-Sato, as well as the Wagner and the Smith formulations for calculating the monostatic and bistatic statistical shadowing functions from a one-dimensional rough stationary surface, which are valid for an uncorrelated Gaussian process with an infinite surface length. In this paper, these formulations are extended to include a finite surface length and any uncorrelated process. The inclusion of a finite surface length is needed to extend the single-reflection shadowing function to the more general multiple-reflection case, presented in the following companion paper. Comparisons of these shadowing functions with the exact numerical solution for the shadowing (using surfaces with Gaussian and Lorentzian autocorrelation functions for a Gaussian process) shows tha...

Content-based fused off-axis object illumination direct-to-digital holography

Abstract: Systems and methods are described for content-based fused off-axis illumination direct-to-digital holography. A method includes calculating an illumination angle with respect to an optical axis defined by a focusing lens as a function of data representing a Fourier analyzed spatially heterodyne hologram; reflecting a reference beam from a reference mirror at a non-normal angle; reflecting an object beam from an object the object beam incident upon the object at the illumination angle; focusing the reference beam and the object beam at a focal plane of a digital recorder to from the content-based off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis; and digitally recording the content based off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis.

Single beam write and/or replay of spatial heterodyne holograms

Abstract: A method of writing a spatially heterodyne hologram having spatially heterodyne fringes includes: passing a single write beam through a spatial light modulator that digitally modulates said single write beam; and focusing the single write beam at a focal plane of a lens to impose a holographic diffraction grating pattern on the photorefractive crystal, the holographic diffraction grating pattern including the spatially heterodyne hologram having spatially heterodyne fringes, wherein only said single write beam is incident on said photorefractive crystal without a reference beam. A method of replaying a spatially heterodyne hologram having spatially heterodyne fringes at a replay angle includes: illuminating a photorefractive crystal having a holographic diffraction grating with a beam from a laser at an illumination angle, the holographic diffraction grating pattern including the spatially heterodyne hologram having spatially heterodyne fringes, wherein a difference between said illumination angle and said replay angle defines a diffraction angle α that is a function of a plane wave mathematically added to original object wave phase and amplitude data of said spatially heterodyne hologram having spatially heterodyne fringes.

Apparatus, method, and program for measuring gap and step

Abstract: PROBLEM TO BE SOLVED: To provide a measuring apparatus for measuring a gap and a step under the condition where an illumination angle of slit light and an imaging angle of an imaging device are kept constant. SOLUTION: A sensor head 200 is provided with a contact 230 which serves as a supporting point abutted on the surface of an object to be measured 400 when an illumination image S formed on the surface of the object 400 is imaged by the slit light illuminated from a slit laser light source 210, in which the contact 230 is attached to a position deviated from the slit light. Based on a position of an image obtained by imaging the illumination image S in an imaging screen, measurement is conducted under the condition that an angle of the sensor head 200 is determined to be appropriate. COPYRIGHT: (C)2004,JPO

Illuminating apparatus for testing

Abstract: To provide an illuminating apparatus for testing which is cost effective and small in size An illuminating apparatus for testing comprising: an illuminating means 1 having a predetermined illumination angle; a first lens 2 for converging light from the illuminating means 1 and converting the light into collimated light; and a second lens 5 for converging light which has passed through through-holes formed in a tested target 3 after having been emitted from the first lens 2 as the collimated light and for making an imaging means 4 take in the light.

Light reflection device and camera with the said device

Abstract: A light emitting device that is capable of changing the illumination angle in the transverse direction while efficiently utilizing energy from a light source. An emission unit includes at least an arc tube. A pair of reflecting means are arranged in a longitudinal direction of the arc tube so as to reflect luminous fluxes emitted from the arc tube in a direction which varies according to the distance between the emission unit and each of the reflecting means.

Auto steering synchronous light

Abstract: The utility model discloses an auto steering synchronous light belonging to an illuminating lamp for automobile, in particular to an illuminating lamp capable of automatically changing illumination angle along with the steering of automobile. The utility model comprises a silver lamp bowl, a plurality of groups of filaments arranged inside the silver lamp bowl and a directional synchronous switch, wherein the control contact of the directional synchronous switch is electrically connected with the leading-out wires of the filaments; in addition, the directional synchronous switch controls the switching on/off of a filament power supply. The utility model can automatically change the illumination angle of illuminating lamp according to the steering of automobile to enlarge the viewing range and eliminate blind area so as to avoid traffic accidents caused by lamplight blind area during running on crooked road at night; therefore, the utility model is suitable to be arranged on automobile for illumination at night.