Abstract: A method for recording information on a rewritable recording medium includes recording first synchronizing signal information in a first synchronizing signal portion on the rewritable recording medium, recording second synchronizing signal information in a second synchronizing signal portion following the first synchronizing signal portion on the rewritable recording medium, recording data information in a data portion of the rewritable recording medium after the second synchronizing signal portion by forming marks in the data portion. The data information corresponds to both ends of each the marks. The marks and spaces between the marks are substantially randomly inverted each time the information is recorded and a length of the first synchronizing signal portion changes and a start position of the first synchronizing signal portion changes. A change of the start position of the first synchronizing signal portion is smaller than a change of the length of the first synchronizing signal portion.

Abstract: The present invention provides a bump shape measuring apparatus comprising an illumination optical system which illuminates bumps arranged on a board with illumination light of a low tilt angle to a surface of the board; a detection optical system where reflected light from the bumps is condensed for detection of image signals of the bumps by a high tilt angle to the surface of the board; an image processing unit where an outline of the tip and the base of each of the bumps is calculated based on the image signals of each of the bumps, and geometric characteristics including at least a position and height of each of the bumps are calculated based on the outline of the tip and the base of each of the bumps; and a main control unit where information on the calculated geometric characteristics of the bumps is displayed on a display unit.

Abstract: A method of measuring variation in dimensions and alignment error of thin film magnetic heads formed on a raw bar cut-off from a substrate is provided. Such method comprises illuminating a MR element and a resistance detector element which is formed for monitoring a lapping process, both of which are formed on the raw bar, with illuminating light whose wavelength is 300 nm or less; forming an image by imaging light reflected from the elements; and converting the image to an image signal through photoelectric conversion so as to detect variation in dimensions of the MR element and the resistance detector element formed on the raw bar, and alignment error between the MR element and the resistance detector element with a high degree of accuracy.

Abstract: In size measurement of a semiconductor device, profiles of a pattern formed in a resist process are determined through an exposure/development simulation in respect of individual different combinations of exposure values and focus values to form a profile matrix and scattered light intensity distributions corresponding to the individual profiles are determined through calculation to form a scattered light library, thereby forming a profile library consisting of the profile matrix and scattered light library. A scattered light intensity distribution of an actually measured pattern is compared with the scattered light intensity distributions of the scattered light library and a profile of profile matrix corresponding to a scattered light intensity distribution of scattered light library having the highest coincidence is determined as a three-dimensional shape of the actually measured pattern.

Abstract: To measure positions of a plurality of thin film magnetic head elements formed in a line on a bar, the quantity of positions of samples in the bar is estimated from the magnetic head elements the amount of deviation in position of the next element, and the distance between the elements are obtained, and the amount of deviation and distance are estimated by a primary approximate linear or several-order approximate curve. The estimated amount and the distance between the elements are moved simultaneously, and an image formed by a lens optical system is photo-converted to an image signal, and dimensions are computed. The conversion step is carried out immediately after movement of the next element and is continuously repeated, and the computing step is processed in parallel with the conversation step.

Abstract: There is provided a method for measuring positions of a plurality of thin film magnetic head elements formed in a line on a bar optically, efficiently, quickly and with high accuracy.

Abstract: A method for automatic focusing and three dimensional profile detection and an apparatus for automatic focusing and three dimensional profile detection have the purpose of detecting a three dimensional profile of the state of mounting of parts or soldering on a board without the affects of warp, even if the board of the detection object is warped, as if the surface of the board were on a flat plane. The board surface height is detected in a plurality of windows corresponding to stage scanning regions from a three dimensional profile signal of the part-mounted board detected by a height detection optical system. The board height or inclination in the next window is forecasted from the board surface height and the control history of stage height in the already-detected plurality of windows.