Method and apparatus for generating values for selected pixels used in evaluating semiconductor wafer bumps
AssigneeElectroglas, Inc.
InventorLeda Villalobos
Life of this patent
Estimating the term…
Abstract
Plural light sources are provided for directing ring patterns of light toward at least one reflective bump formed on and projecting from a first wafer surface of a semiconductor wafer. The intensity of light from the light sources may be varied and may be varied independently of one another. A method and apparatus for adjusting at least one pixel value is also disclosed.
Claims27
A method of adjusting the value of at least one selected pixel in a group of pixels representing light reflected from a bump which projects from a wafer surface, the method comprising:
- selecting at least one pixel having a value which is to be adjusted;
- determining a gray level gradient in a plurality of directions with respect to the selected pixel;
- and
- adjusting the value of the selected pixel based upon the values of pixels along the direction at which the gray level gradient is the greatest, whereby the value of the selected pixel is adjusted to more accurately correspond to light reflected from the bump.
A method of adjusting the value of at least one selected pixel from a time delay and integration camera such that the value of the pixel more accurately corresponds to light reflected from a light reflective bump projecting from a wafer surface, the method comprising:
- selecting a pixel having a value which is to be adjusted;
- determining a gray level gradient in a plurality of directions with respect to the selected pixel;
- determining the direction from the plurality of directions along which the gray level gradient is the greatest;
- and
- adjusting the value of the selected pixel based upon the values of pixels along the direction at which the gray level gradient is the greatest.
A method of adjusting the value of at least one selected pixel in a group of pixels from a time delay and integration camera comprising:
- selecting at least one dead pixel from the time delay and integration camera output;
- determining a gray level gradient in a plurality of directions with respect to the selected pixel;
- determining the direction from the plurality of directions along which the gray level gradient is the greatest;
- and
- adjusting the value of the selected pixel based upon the values of pixels along the direction at which the gray level gradient is the greatest.
A method of adjusting the value of at least one selected pixel in a group of pixels arranged in columns and rows, the method comprising:
- determine a neighborhood of a plurality of pixels adjacent to the selected pixel;
- determining the direction of the maximum gray line gradient of pixels in the neighborhood along a plurality of directions intersecting the selected pixel;
- and
- adjusting the value of the selected pixel by assigning a value to the selected pixel corresponding to the value the selected pixel would have along the line having the maximum gray line gradient.
An apparatus for adjusting the value of at least one selected pixel in a group of pixels representing light reflected from a bump which projects from a wafer surface, the apparatus comprising:
- a time delay and integration camera which produces an output of pixels corresponding to an array of pixels having a plurality of rows and columns;
- and
- a processor operable to substitute a computed pixel value for the pixel value corresponding to at least one selected pixel, the processor being operable to evaluate the values of a plurality of pixels in proximity to the at least one selected pixel and to determine a direction from the evaluated pixel along which a maximum gray line gradient is located, the processor assigning a value to the at least one selected pixel based upon the values of pixels along the line having the maximum gray line gradient.
An apparatus for adjusting the value of at least one selected pixel in a group of pixels representing light reflected from a bump which projects from a wafer surface, the apparatus comprising:
- means for determining the maximum gray line gradient along a line intersecting a plurality of pixels and a selected pixel;
- means for assigning a pixel value to the selected pixel corresponding to the value the pixel would along the line of maximum gray line gradient.
Dependencies are inferred from the claim text.