摘要:
An inspection method and apparatus which controls an acceleration voltage of an electron beam, irradiates the electron beam to an object to be inspected mounted on a stage which is continuously moving at least in one direction, detects at least one of a secondary electron and a reflected electron emanated from the object by the irradiating, obtains an image of the object from the detected electron by using positional information of the stage, conducts inspection or measurement of the object using the image obtained, and outputs a result of the inspection or the measurement through a network system which is connected to a computer.
摘要:
An electron beam inspection method including the steps of irradiating an electron beam to an object to be inspected, detecting at least one of a secondary electron and a reflected electron emanated from the object by the irradiation of the electron beam, and obtaining an image of the object from the detected electron. The method further includes the steps of controlling an electric field in a neighborhood of the object for filtering the at least one of the secondary and reflected electron emanated from the object so as to control the contrast of the image, detecting at least one of the secondary and reflected electron emanated from the object which passes through the electric field in the neighborhood of the object by the irradiation of the electron beam, and conducting inspection or measurement of the object on the basis of a detected signal of the detection in the controlled electric field.
摘要:
In a recording and reproducing apparatus for a disc-shaped recording medium, and a defect substitution method for a disc-shaped recording medium, whether reproduction of recorded data is good is determined by sector unit and not by product code unit, defective sector discrimination is performed by sector unit, and only sectors determined defective are alternately recorded, when using a recording format in which data that is error detection and correction coded with a product code is segmented and recorded to a plurality of sectors.
摘要:
An electron beam inspection method and apparatus. The method includes controlling acceleration voltage of electron beam and electric field on a sample, beam current, beam diameter, image detection rate, image dimensions, precharge, discharge, or a combination of them, exposing an object to the electron beam, detecting in a sensor a physical change generated from the object, and inspecting or measuring the object on the basis of a signal representing the detected physical change. The apparatus includes an electron source (potential E2) for generating an electron beam, a deflector for scanning generated electrons, an objective lens for focusing the electron beam upon the object, a grid (potential E1) disposed between the object and the objective lens, a wafer holder (potential E0) for holding the object, a sensor for detecting generated secondary electrons, a potential controller for controlling the potential E0, E1 and E2, and a storage for storing optimum potential conditions. By changing conditions of an electron optic system such as potential E0, E1 and E2, the acceleration voltage and electric field on the object are controlled. For a material located at least in an upper layer of a plurality of materials forming the object, the secondary electron yield ratio can be made nearly unity and appropriate contrast of an obtained image can be provided with minimized influence of charge up.
摘要:
A multi-layered optical disk comprising a plurality of recording layers accumulated in the thickness direction wherein a light beam is focused on one of tracks of one of the layers thereby to record and reproduce data, the optical disk being characterized in that recording layers each have an identification section storing an address of the recording layer which the identification section belongs to.
摘要:
A multi-layered optical disk comprising a plurality of recording layers accumulated in the thickness direction wherein a light beam is focused on one of tracks of one of the layers thereby to record and reproduce data, the optical disk being characterized in that recording layers each have an identification section storing an address of the recording layer which the identification section belongs to.
摘要:
A method of recording and reproducing data on and from a rewritable optical disk used for recording/reproduction of data on a sector by sector basis. A dummy block or a parity subject to error detection and correction coding is additionally recorded at the rear of a data block on a sector. A defect caused by deterioration due to reiterative operation at the trail of the sector can be prevented from reaching the data block and data can be reproduced with high reliability.
摘要:
A disk shaped information recording medium has a virtual ROM area where data sectors, and parity sectors are recorded, and a disk definition area where management data of a virtual ROM area is recorded in a rewritable user area information recording and reproducing apparatus fabricates the information recording medium. Also, the information recording and reproducing apparatus prohibits a data recording operation with respect to the virtual ROM area and recovers a data of the defective sector detected in the virtual ROM area using a parity sector.
摘要:
A double-sided optical disc player which comprises first and second optical heads for radiating laser beams to tracks on respective sides of a double-sided optical disc; first and second ID read-out units for reading respective sector addresses out from associated sector identifiers; an ID offset detecting unit for calculating, in response to outputs from the ID read-out unit, the ID offset value descriptive of an angular displacement in sector position between the opposite sides of the optical disc traced by the associated optical heads; an ID offset retaining unit for retaining the ID offset value; a first sector recording and/or production control unit for detecting a target sector when an sector address output from the first ID read-out unit coincide with the target sector and for activating a recording or reproduction of information; an adder for adding the ID offset value to an output from the second ID read-out unit; a second sector recording and/or reproduction control unit for detecting a target object when an corrected sector address outputted from the adder coincides with the target sector and for activating the recording or reproduction of the information; and an information recording and/or reproducing unit for recording or reproducing information on or from the target sectors on the respective sides of the optical disc by means of the first and second sector recording and/or reproduction control units.
摘要:
An information recording and reproducing apparatus detects deterioration in a recording medium. Structure is provided for recording information including an error correction code. A signal indicative of recorded information is received, and an error signal indicative of a number of errors that are detected is produced. This error signal is based on verification of the error correction code. The error correction code is verified using a strict clipping level, which is a level stricter than a usual level recognized as a particular signal level. This strict clipping level is compared with the signal indicative of reading areas, and error signals are produced thereby. When the error signal indicates a number of errors greater than a predetermined number, each sector is checked to determine if it is a bad sector. Each bad sector is recorded with a mark signal that indicates a bad sector. Before writing on the disk, each target sector is read verified using the strict clipping level, and mark signals indicative of a bad sector are recorded on any bad sectors. According to another aspect, the read verify operation is also carried out for a directory sector to ensure that the directory sector is correct.