Other

Kla Instruments Corporation

David J Harvey

Michael E Fein

William T Bell

Curt H Chadwick

John D Greene

Robert R Sholes

P C Jann

Francis D Tucker, Iii

In each configuration, at least one TDI sensor is used to image substrate portions of interest, with those portions illuminated with substantially uniform illumination. In one configuration, a substrate is compared to prestored expected characteristic features. In a second configuration, first and second patterns in a region of the surface of at least one substrate are inspected by comparing one pattern against the other and noting whether they agree with each other. This is accomplished by illuminating the two patterns, imaging the first pattern and storing its characteristics in a temporary memory, then imaging the second pattern and comparing it to the stored characteristics from the temporary memory. Then the comparisons continue sequentially with the second pattern becoming the first pattern in the next imaging/comparison sequence against a new second pattern. Each time the comparison is performed, it is noted whether or not there has been agreement between the two patterns and which two patterns where compared. This inspection technique is useful for doing die-to-die inspections. A variation of the second configuration uses two TDI sensors to simultaneously image the first and second patterns, thus eliminating the need for temporary memory. In this configuration, the two patterns are simultaneously imaged and compared, then additional patterns are compared sequentially, in the same manner with the results of the comparisons and the pattern locations stored to determine which patterns are bad when the inspection of all patterns is completed.

Automatic high speed optical inspection system

Substrate inspection apparatus and methods, and illumination apparatus. The inspection apparatus and method includes memory for storing the desired features of the surface of the substrate, focussed illuminator for substantially uniformly illuminating a region of the surface of the substrate to be inspected. Additionally there is a sensor for imaging the region of the substrate illuminated by the illuminator, and a comparator responsive to the memory and sensor for comparing the imaged region of the substrate with the stored desired features of the substrate. The illumination apparatus is designed to provide substantially uniform focussed illumination along a narrow linear region. This apparatus includes first, second and third reflectors elliptically cylindrical in shape, each with its long axis substantially parallel to the long axes of each of the others. Fourth and fifth reflectors are also included with each being flat and mounted parallel to each other and at opposite ends of each of said first, second and third reflectors, and first, second and third linear light sources each mounted parallel to a corresponding one of said first, second and third reflectors with each of the light sources mounted so that it is at the first focus of the corresponding reflector and the illuminated linear region is at the second focus of each of the first, second and third reflectors.

Method and apparatus for optical inspection of substrates

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Campbell, CA, United States of America

David J Harvey