摘要:
The present invention relates generally to an apparatus and method for measuring nuclear magnetic resonance properties of an earth formation traversed by a borehole by generating gradient-echoes. The measurement can be made while drilling or using a wireline tool. The apparatus applies a static magnetic field, B.sub.a, in a volume of the formation which polarizes the nuclei of hydrogenous connate fluids within the formation. The apparatus applies a second magnetic field, B.sub.b, in a volume of the formation. The magnetic fields B.sub.a and B.sub.b are substantially orthogonal in the volume of the formation. A change in the polarity of the magnetic field, B.sub.b, reverses the direction of precession of the nuclei thereby generating a train of gradient-echoes. Each gradient-echo signal is transformed into the frequency domain and the signal frequency is mapped to a radial position in the volume of the formation in order to generate an image of the formation. Various properties of the formation, such as the effective diffusion coefficient of the formation fluid, longitudinal relaxation time, spin--spin relaxation time, and porosity can be estimated from the train of gradient-echoes.
摘要:
A high vertical resolution antenna design is provided for use in an NMR measurement apparatus. Multiple coils are situated along the length of a magnet. A primary coil is energized to cause an oscillating magnetic field in a portion of earth formation surrounding a borehole. A secondary coil having smaller dimensions than the primary coil is operated to receive spin echoes from a depth of investigation associated with the secondary coil. A distance sufficient to minimize electrical coupling separates the coils. The separation distance can be reduced by selecting a secondary coil with orthogonal polarization to the primary coil. Alternatively, a cross coil configuration can be implemented where the orthogonal secondary coil at least partially overlaps the primary coil, thereby reducing the overall length necessary for the polarizing magnet.
摘要:
A downhole NMR measurement apparatus for use in a borehole includes at least one magnet, at least one RF transmission coil, at least one gradient coil and circuitry. The magnet(s) establish a magnetic field in a region of a formation that at least partially surrounds the measurement apparatus. The RF transmission coils(s) transmit RF pulses pursuant to an NMR pulse sequence into the region to, in combination with the magnetic field, induce the generation of spin echo signals from a resonance volume within the region. The gradient coil(s) establish a pulsed gradient field in the resonance volume, and the circuitry is coupled to the gradient coil(s) to control the generation of the pulsed gradient field to phase encode the spin echo signals for purposes of high resolution imaging of the formation.
摘要:
Disclosed is a method, apparatus, and program product for routing an electronic design using sidewall image transfer that is correct by construction. The layout is routed by construction to allow successful manufacturing with sidewall image transfer, since the router will not allow a routing configuration in the layout that cannot be successfully manufactured with a two-mask sidewall image transfer. A layout is produced that can be manufactured by a two-mask sidewall image transfer method. In one approach, interconnections can be in arbitrary directions. In another approach, interconnections follow grid lines in x and y-directions.
摘要:
An apparatus and method for modifying a mask data set includes calculating a derivative of a figure-of-merit, indicative of a data set defined by a plurality of polygon edges and then segmenting polygon edges in response to said step of calculating.
摘要:
An apparatus and method for improving image quality in a photolithographic process includes calculating a figure-of-demerit for a photolithographic mask function and then adjusting said photolithographic mask function to reduce the figure of demerit.
摘要:
A method of measuring flare in an optical lithographic system utilizes an exposure mask with first and second discrete opaque features each having rotational symmetry of order greater than four and of different respective areas. The exposure mask is positioned in the lithographic system such that actinic radiation emitted by the lithographic system illuminates the sensitive surface of an exposure target through the exposure mask. The extent to which regions of the sensitive surface that are within the geometric image of a feature of the exposure mask are exposed to actinic radiation during due to flare is measured.
摘要:
Computational models of a patterning process are described. Any one of these computational models can be implemented as computer-readable program code embodied in computer-readable media. The embodiments described herein explain techniques that can be used to adjust parameters of these models according to measurements, as well as how predictions made from these models can be used to correct lithography data. Corrected lithography data can be used to manufacture a device, such as an integrated circuit.
摘要:
A method and system for reducing the computation time required to apply position-dependent corrections to lithography, usually mask, data is disclosed. Optical proximity or process corrections are determined for a few instances of a repeating cluster or object, usually at widely separated locations and then interpolating the corrections to the other instances of the repeating cluster based on their positions in the exposure field. Or, optical proximity corrections can be applied to the repeating cluster of objects for different values of flare intensity, or another parameter of patterning imperfection, such as by calculating the value of the flare at the location of each instance of the repeating cluster, and interpolating the optical proximity corrections to those values of flare.
摘要:
A method for measuring overlay in semiconductor wafers includes a calibration phase in which a series of calibration samples are analyzed. Each calibration sample has an overlay that is known to be less than a predetermined limit. A difference spectrum for a pair of reflectively symmetric overlay targets is obtained for each calibration sample. The difference spectra are then combined to define a gross overlay indicator. In subsequent measurements of actual wafers, difference spectra are compared to the overlay indicator to detect cases of gross overlay.