Method of analyzing visual inspection image data to find defects on a device
AssigneeInternational Business Machines Corporation
InventorsPierre M. Companion, Karl K. Moody, III, Brenda M. Wilson
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Abstract
A method for analyzing image data is disclosed that will find defects on a multi-layer device having solder pads, such as a semiconductor computer chip. The method provides a device template image, a theoretical image created from data from several real images, for comparison to an image of a device to be tested after the solder pad data is segmented. The parameter values of the device to be tested are recorded and compared to the parameter values of the device template, forming a difference image. The difference image and the solder pad data are then run through a series of tests, wherein the device is determined defective or not defective.
Claims17
A method of analyzing visual inspection image data to find defects on a device under test, comprising the steps of:
- a) providing a plurality of good devices;
- b) imaging each of said good devices to provide a plurality of images of said good devices, said images of said good devices each comprising pixels;
- c) comparing value of a first image parameter of each pixel of each good device to a first threshold value and converting said value to black or to white depending on whether said value is above or below said first threshold value;
- d) deriving a device template image from said plurality of converted images of said good devices, said device template image comprising a device template image pixel corresponding to each good device pixel for said first image parameter;
- e) providing the device under test;
- f) imaging the device under test, to provide an image of the device under test comprising pixels corresponding to said pixels of said good devices;
- g) subtracting said first image parameter of said device under test pixel by pixel from said template image to provide a difference image for said first image parameter;
- h) comparing the value of each pixel of said difference image to a second threshold value;
- i) converting the value of each pixel to black or white depending on whether the value of that pixel is above or below the second threshold value to generate a final corrected difference image;
- and
- j) identifying a defect on the device under test from said final corrected difference image.
A method of analyzing visual inspection image data to find defects on a device under test, comprising the steps of comparing an image parameter value of a region of a device to a first color, pixel by pixel, until said image parameter value of said region deviate from a set range of color values to determine defects in said region.
A method of analyzing visual inspection image data to find defects in solder pads on a device, comprising the steps of:
- a) providing a device having a first and a second solder pad;
- b) imaging said first solder pad to provide a first solder pad image and imaging said second solder pad to provide a second solder pad image;
- c) comparing said first solder pad image to said second solder pad image to detect a defect in one of said solder pads;
- and
- d) measuring said first solder pad image and comparing said measurement to a criterion comprising at least one of circularity, convexity, radius, surface area, center of mass, and eccentricity, wherein said criteria comprises a previously determined range of acceptable values.
Dependencies are inferred from the claim text.