Wafer inspection system
First Claim
Patent Images
1. A method of identifying a defect and performing a quality inspection comprising the steps of:
- providing a wafer having a surface;
providing a non-vibrating contact potential difference sensor;
scanning the semiconductor wafer relative to the non-vibrating contact potential difference sensor, the scanning step generating a signal from changes in contact potential difference;
generating contact potential difference data from the signal from changes in contact potential difference;
processing the non-vibrating contact potential difference sensor data to automatically detect a pattern that represents the defect; and
outputting the pattern that represents the defect in order to carry out a quality inspection of the wafer.
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Abstract
A method and system for identifying a defect or contamination on a surface of a material. The method and system involves providing a material, such as a semiconductor wafer, using a non-vibrating contact potential difference sensor to scan the wafer, generate contact potential difference data and processing that data to identify a pattern characteristic of the defect or contamination.
66 Citations
44 Claims
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1. A method of identifying a defect and performing a quality inspection comprising the steps of:
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providing a wafer having a surface; providing a non-vibrating contact potential difference sensor; scanning the semiconductor wafer relative to the non-vibrating contact potential difference sensor, the scanning step generating a signal from changes in contact potential difference; generating contact potential difference data from the signal from changes in contact potential difference; processing the non-vibrating contact potential difference sensor data to automatically detect a pattern that represents the defect; and outputting the pattern that represents the defect in order to carry out a quality inspection of the wafer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. A method of denoising signal data from a non-vibrating contact potential difference sensor inspecting a wafer, comprising the steps of:
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generating signal data from a contact potential difference sensor characteristic of a surface of a wafer; decomposing the signal data into a wavelet domain; obtaining a plurality of coefficients at a finite number of scales; selecting for a peak signal selected by selecting only wavelet coefficients at fine scales and by shrinking the fine scale coefficients based on a threshold; reconstructing the data by the coefficients in reverse order; and outputting the reconstructed data to carry out an improved quality inspection of the wafer. - View Dependent Claims (33, 34)
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35. A method of removing a time delay from a non-vibrating contact potential difference sensor signal from inspecting a wafer, comprising the steps of:
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generating a non-vibrating contact potential difference sensor signal characteristic of a wafer; modeling a circuit as a first order RC circuit; converting the non-vibrating contact potential difference sensor signal into a discrete time transfer function; determining the impulse response of the discretized time transfer function; deconvoluting each data track separately to produce a deconvoluted sensor signal; and outputting the deconvoluted sensor signal to carry out a quality inspection of the wafer.
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36. A system for identifying a category of defect on a surface of a wafer, comprising:
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a non-vibrating contact potential difference sensor; a height sensor for measuring height of the contact potential difference sensor above the surface of the wafer to control the height and thereby produce repeatable identification of the category of defect; a device for moving the non-vibrating contact potential difference sensor relative to the semiconductor wafer; and a computer for receiving and analyzing wafer data generated by the non-vibrating contact potential difference sensor and the height sensor and processing the non-vibrating contact potential difference sensor and the height sensor data to automatically detect a pattern that represents a defects. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43)
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44. A method of identifying a defect comprising the steps of:
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providing a wafer having a surface; providing a reference source for data processing; providing a non-vibrating contact potential difference sensor; scanning the semiconductor wafer relative to the non-vibrating contact potential difference sensor; generating contact potential difference data from the non-vibrating contact potential difference sensor; processing the non-vibrating contact potential difference sensor data to automatically detect a pattern that represents the defect with the reference source enabling at least one of signal generation, image production and absolute distance measurement; and utilizing the pattern that represents the defect to carry out a quality inspection of the wafer.
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Specification