Simultaneous multi-bandwidth optical inspection of semiconductor devices

1 . A method of qualifying semiconductor wafer processing, said method comprising:

illuminating a semiconductor wafer simultaneously with source light having wavelengths in a plurality of wavebands, including at least a first waveband and a second waveband emitted by a common light source, said second waveband partially overlapping the first waveband, wherein the illuminating comprises:

regulating at least one of an aperture and a polarization of the source light having wavelengths in the first waveband and

regulating at least one of an aperture and a polarization of the source light having wavelengths in the second waveband,

wherein regulating of the source light having wavelengths in the second waveband is done independently of regulating of the source light having wavelengths in the first waveband, and

wherein the source light having wavelengths in the first waveband is combined with the source light having wavelengths in the second waveband after the regulating;

separating light reflected from the semiconductor wafer as a result of said illuminating, said separating dividing the reflected light according to waveband;

generating a first image of the semiconductor wafer based on reflected light separated into the first waveband;

generating a second image of the semiconductor wafer based on reflected light separated into the second waveband; and,

analyzing the first and second images to qualify the semiconductor wafer based on a predetermined value of a defect count,

wherein the analyzing includes applying a first imaging processing to the first image generated based on the reflected light separated into the first waveband to detect a first type of defect in the semiconductor wafer and applying a second imaging processing to the second image generated based on the reflected light separated into the second waveband to detect a second type of defect in the semiconductor wafer, wherein the first type of defect and the second type of defect are different types of defects.

2 . The method of claim 1 , wherein said generating of the first and second images includes:

directing reflected light separated into the first waveband along a first optical path to a first image sensor from which the first image is generated; and

directing reflected light separated into the second waveband along a second optical path to a second image sensor from which the second image is generated, said second image sensor being different than the first image sensor.

3 . The method of claim 1 , wherein said illuminating comprises:

regulating the aperture of the source light having wavelengths in the first waveband; and

regulating the polarization of the source light having wavelengths in the second waveband.

4 . The method of claim 1 , wherein the illuminating comprises:

regulating the aperture of the source light having wavelengths in the first waveband; and

regulating the aperture of the source light having wavelengths in the second waveband.

5 . The method of claim 1 , wherein said illuminating further comprises:

independently conditioning at least one of intensity and/or beam spot of the source light having wavelengths in the first waveband and source light having wavelengths in the second waveband.

6 . The method of claim 1 , wherein the illuminating comprises:

regulating the polarization of the source light having wavelengths in the first waveband; and

regulating the polarization of the source light having wavelengths in the second waveband.

7 . The method of claim 1 , wherein the analyzing includes:

classifying the defects detected by applying the first imaging processing to the first image as defects of the first type of defect.

8 . The method of claim 7 , wherein the analyzing further includes:

classifying the defects detected by applying the second imaging processing to the second image as defects of the second type of defect.

9 . The method of claim 1 , further comprising:

combining the first image with the second image to produce a resulting image;

wherein the analyzing further includes image processing the resulting image to detect at least one defect in the semiconductor wafer.

10 . An optical inspection apparatus for qualifying semiconductor wafer processing, said apparatus comprising:

an illumination module producing source light illuminating a semiconductor wafer, said illumination module including:

a common light source that emits light having wavelengths in a first waveband and a second waveband, wherein the first waveband and the second waveband partially overlap;

a first optical element comprising a first aperture wheel having multiple apertures arranged along a first optical path of the first waveband, said first aperture wheel regulating a first optical parameter of the first waveband; and

a second optical element comprising a second aperture wheel having multiple apertures arranged along a second optical path of the second waveband, and said second aperture wheel regulating a second optical parameter of the second waveband;

a collection module including a first image sensor and a second image sensor, said first image sensor receiving reflected light in the first waveband from the semiconductor wafer and said second image sensor receiving reflected light in the second waveband from the semiconductor wafer; and

an image processor that processes a first image of the semiconductor wafer generated in accordance with data obtained from the first image sensor, and processes a second image of the semiconductor wafer generated in accordance with data obtained from the second image sensor to qualify the semiconductor wafer based on a predetermined value of a defect count.

11 . The optical inspection apparatus of claim 10 , wherein the first optical element further includes a first polarizer, and the second optical element further includes a second polarizer.

12 . The optical apparatus of claim 10 , wherein the illumination module further comprises:

dividing optics that separates light emitted from the common light source according to waveband, such that light emitted from the common light source in the first waveband is directed along the first optical path, while light emitted from the common light source in the second waveband is directed along the second optical path.

13 . The optical apparatus of claim 10 , wherein:

the illumination module produces the source light emitted by a common light source that emits light, and further includes combining optics that combine the source light in the first waveband after it passes through the first optical element with the source light in the second waveband after it passes through the second optical element; and

the image processor combines the first image of the semiconductor wafer and the second image of the semiconductor wafer together to produce a resulting image and processes the resulting image to detect if there is a defect in the semiconductor wafer.

14 . An inspection method for qualifying semiconductor wafer processing, said method comprising:

illuminating a semiconductor wafer with source light having wavelengths in a plurality of wavebands, including at least a first waveband and a second waveband, said second waveband partially overlapping the first waveband;

prior to the illuminating, conditioning the source light having wavelengths in the first waveband including regulating one of an aperture provided for the source light having wavelengths in the first waveband and a polarization of the source light having wavelengths in the first waveband, and conditioning the source light having wavelengths in the second waveband including regulating one of an aperture provided for the source light having wavelengths in the second waveband and a polarization of the source light having wavelengths in the second waveband, wherein said conditioning of the source light having wavelengths in the second waveband is carried out independently of said conditioning of the source light having wavelengths in the first waveband;

separating light reflected from the semiconductor device as a result of said illuminating, said separating dividing the reflected light according to waveband such that reflected light in the first waveband is directed to a first image sensor, while reflected light in the second waveband is directed to a second image sensor;

generating a first image of the semiconductor wafer in accordance with data produced from the first image sensor;

generating a second image of the semiconductor wafer in accordance with data produced from the second image sensor; and

applying a convolution neural network (CNN) to the first and second images to simultaneously detect and classify defects.

15 . The method of claim 14 , further comprising:

applying the CNN to detect and classify a first type of defect in the semiconductor wafer; and

applying the CNN to detect and classify a second type of defect in the semiconductor wafer.

16 . The method of claim 14 , further comprising:

combining the first image with the second image to produce a resulting image; and

applying the CNN to the resulting image to detect and classify defects in the semiconductor wafer.

17 . The method of claim 14 , wherein:

conditioning the source light having wavelengths in the first waveband further includes regulating a polarization of the source light having wavelengths in the first waveband; and

conditioning the source light having wavelengths in the second waveband further includes regulating a polarization of the source light having wavelengths in the second waveband.

18 . The method of claim 14 , wherein the CNN is a region based CNN.

19 . The method of claim 14 , further comprising:

prior to conditioning the source light, separating light emitted from the common light source according to waveband, such that light emitted from the common light source in the first waveband is directed along a first optical path, while light emitted from the common light source in the second waveband is directed along a second optical path.

20 . The method of claim 14 , wherein:

conditioning the source light having wavelengths in the first waveband further includes regulating an aperture of the source light having wavelengths in the first waveband; and

conditioning the source light having wavelengths in the second waveband further includes regulating a polarization of the source light having wavelengths in the second waveband.