Method of inspecting chip defects
AssigneeNational Applied Research Laboratories
InventorsMing-Fu Chen, Chun-Chao Chang
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Abstract
The present invention provides a method for inspecting chip defects. A raw image of a chip is used to extract a chip image. A binary chip edge image obtained from the chip image is used for inspecting defects, coordinated with statistics of edge pixels. During packaging the chip, defects that exceed inspection criteria and affect chip quality are quantitatively and accurately inspected out. The present invention has a simple procedure with high performance on inspecting defect modes and defect sizes. Thus, the present invention greatly improves performance and accuracy of inspections on chip defects for further saving a great amount of labor, time and cost.
Claims11
A method of inspecting chip defects, comprising steps of:
- (a) acquiring a raw image of a chip;
- processing the raw image through edge detection to obtain a raw edge image;
- after obtaining said raw edge image, determining a plurality of locations of edge points of possible boundaries and a plurality of locations of edge points of possible corners through chip boundaries derivation and chip corners derivation;
- deriving equations and parameters of affine transformation of a plurality of coordinates of the raw image and coordinates of the determined edge points to obtain coordinates of a chip image;
- and, according to the coordinate systems of said raw image and said chip image and according to said equations and parameters of affine transformation, an image region of said chip is acquired and segmented through chip image segmentation based on said raw image and said raw edge image to obtain said chip image and a chip edge image;
- and
- (b) inspecting defects of said chip,
- wherein, for various defect modes and various potential defect regions, a corresponding size of a defect mode scan window is set and the corresponding scan window is used to process various inspections on said chip edge image in a way of region by region;
- statistics of edge pixels at two inter-perpendicular directions are gathered;
- and, according to numbers of pixels obtained from said statistics of edge pixels, said inspections are processed, said inspections for various defect modes comprising an inspection of crack defects, an inspection of chipping defects and an inspection of residual-glue defects.
Dependencies are inferred from the claim text.