Patent ID: 6441398
Filing Date: 2002-08-27
Classification: H01L

Abstract:
An integrated circuit comprising:active-region regions; interconnect paths electrically connecting the active-regions to implement a desired circuit function; and contact holes formed in the active-region regions where connections with the interconnect paths are needed, wherein each of the contact holes are inspected during formation to detect sloped contact holes by, (a) generating a waveform for the contract hole; (b) calculating a critical dimension (CD) for the contact hole using the waveform; (c) calculating a first derivative curve for the waveform; (d) setting a percentage of slope threshold; (e) plotting the percentage of slope threshold on the first derivative curve; (f) locating an inner diameter of the contact hole on the waveform using the percentage of slope threshold on the first derivative curve; (g) calculating the edge width of the contact hole using the inner diameter; (h) comparing the edge width with a predetermined limit; (i) determining that the contact hole has sloped sidewalls if the edge width is outside of the predetermined limit.