JP2001099630A - Method and system for multiband uv lighting of wafer for optical microscope wafer inspection and measurement system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize a method and a system for multiband UV lighting which is technically adaptive to various applications, advantageous in cost, and hardly broken. SOLUTION: This system is equipped with a light source which has two UV narrow bands of 360 to 370 nm and 398 to 407 nm and a single visual narrow band of 427 to 434 through broadband and individualband filtering, an optical microscope characterized by a broadband objective system, a lighting path, and a tube lens, a camera, and a data processor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination method and system used in an optical microscope applied to a wafer inspection and measurement system, and more particularly to a multiband UV of a wafer for use in an optical microscope wafer inspection and measurement system. Light (ultraviolet) illumination method and system.

[0002]

BACKGROUND OF THE INVENTION In the semiconductor industry, optical microscope wafer inspection and metrology systems are widely used in the research, development and manufacture of silicon substrate wafers. The use of optical microscope wafer inspection and metrology systems
It allows close-ups of features associated with the detection, analysis, and measurement of wafer surface features, particularly defects, patterns, and other surface structures. Specific examples of optical microscope wafer inspection and metrology system applications include wafer defect detection, optical overlay measurement, and optical CD (critical dimensio).
n: critical dimension) and the field of control. Wafer topography features are particularly important in quality control processes used along successive stages of wafer fabrication. Furthermore,
Full scale to new wafer manufacturing
Due to the large resource consumption at the (full-scale) production level, a suitable optical microscope wafer inspection or metrology system must be technically viable and powerful to be useful in a manufacturing environment.

[0003] Hereinafter, "CD" or "critical dimens"
The term "ion" shall refer to the smallest dimension of a structure on a wafer that can be controlled by the wafer fabrication process.
The term "pattern" refers to an intended or desired pattern, design, structure or shape having measurable dimensions on a wafer. The term "defect" is intended to refer to imperfections in the wafer, such as the presence of undesired structures or shapes on the wafer or the absence of the desired structures or shapes, having measurable dimensions. In addition, current technology in the semiconductor industry uses 180 nm as the reference critical dimension for wafer patterns. Furthermore, "killer defects" directly affect the function of special patterns on a wafer, i.e.
It's a defect of sufficient size to say "kill." At present, a defect is usually classified as a killer defect if it is half of the currently used critical dimension of 180 nm, ie 90 nm. In metrology applications, the required accuracy is better than 10% of this critical dimension, ie less than 20 nm. Clearly, as well as performing edge detection, the ability to detect killers and other wafer defects early in the cycle of new wafer development and manufacturing is critical.

Specific wafer inspection (observation)
Or the particular method and system of illumination used in the metrology system strongly dictates the overall quality of the results obtained from the wafer inspection or metrology system. Current methods and systems of illumination employed in optical microscope wafer inspection and metrology systems include broadband (wide) white light and single (narrow) narrow band U
Includes wafer illumination using V light. Narrow band UV light is “monochromatic (monochrome)” when it is in a sufficiently narrow wavelength range.
It is widely known that it is also called. The present invention uses the terms "narrow band" and "monochromatic" UV light. White light illumination refers to broadband illumination in the visible light spectrum. Wafer inspection and metrology optical microscopy provides broadband white light in the 400 nm-800 nm visible spectrum, 250 nm-5
Narrow band monochromatic U in the 00 nm spectral range
Lamps specially designed to produce V light and also other light spectra, including, for example, a few narrow bands in the visible spectral range (eg, comprising high or low pressure mercury vapor mixed with a noble gas). Including.

The type of illumination source used in optical microscopes is
An important factor in determining the resolution of an image, where the resolution of the image is such that the light intensity between the two black objects or structures is reduced to 0.707 of the image amplitude, brightness, or intensity between these two objects. Follow standard optical definitions, such that the time is resolved. Such a definition can be found in the reference text "P
rinciples of Optics: Electromagnetic Theory of Prop
agation, Interferenceand Diffraction of Light ", 6t
h edition, Born, Max, and Wolf, Emil, Cambridge Un
Presented in iversity Press, 1998.

[0006] The results of wafer images obtained by using an optical microscope for wafer inspection or metrology are adversely affected by diffraction. Diffraction results from the interaction between light waves of a given illumination source and objects or structures (eg, patterns or defects) on the wafer surface. Here, the diffraction effect is considered as system noise (noise) that directly lowers the quality of the wafer image. For a given wafer surface profile, the degree of diffraction is a function of the microscope optics (eg, lens system or objective aperture) and the illumination spectrum (ie, white light vs. broadband UV light vs. monochromatic illumination). While monochromatic UV light illumination of a wafer provides higher image resolution than broadband white light illumination of a wafer, monochromatic UV light illumination produces greater diffraction effects as compared to broadband white light illumination, especially for patterns and / or defects. This is especially true on wafers that characterize multiple objects or structures near each other, known as.

In an optical microscope wafer inspection and metrology system that relies on the actual goal of the method, the wafer defect or pattern in the vicinity of the wafer pattern or other wafer defects or patterns (eg, wafer defect or pattern It is usually important to design wafer illumination methods and systems that allow proper detection of clusters (inspection or measurement), resolution and measurement of critical dimensions. In such a case,
In addition to the standard image resolution of individual defects and patterns,
Diffraction effects become very important in the analysis of image data. In addition to the image resolution of a single object or structure commonly used, the proper characterization of the results of image analysis of a wafer limited by diffraction effects has a unit of distance, and is a measure of wafer inspection or metrology techniques. Includes the use of the term "system resolution" which is commonly defined in the art as the distance between a first defect or pattern and the edge of another defect or pattern on the same wafer, whereby the first defect or pattern is The accuracy of pattern detection or measurement is statistically high even in the presence of diffraction effects caused by edges of other patterns or defects. Further, for example, for a wafer defect detection system, system resolution refers to the distance between a first defect on the same wafer and an edge of another defect or pattern;
The probability of detecting a defect remains statistically significant.

The numerical value of the system resolution related to a predetermined method of the wafer inspection system is, for example, nm
, And decreases as the system resolution increases. 500n from pattern or other defects
A resolvable defect at a distance of m indicates that the system has a higher system resolution than a method where the defect can be resolved at a distance of 1000 nm, which is farther from the pattern or other defect. A way to increase system resolution measurably is to use wafer inspection or metrology methods and systems that reduce diffraction effects, resulting in an effective reduction in defect or pattern edge size. Thus, in order to properly design an effective method and system of wafer illumination for use in a given optical microscope wafer inspection system with respect to the image quality of the wafer characterizing multiple objects or structures (ie, patterns, defects). At the same time, it is necessary to describe and determine the optimization of the three parameters related to resolution. These three parameters are (1)
Image resolution of a single object or structure, (2) diffraction effects,
(3) System resolution.

In the method and system for an optical microscope wafer inspection and measurement system that employs broadband illumination of a wafer, the diffraction effect is small enough to be measurable compared to methods that employ barrowband or monochromatic illumination of the wafer. Is widely known. actually,
Broadband illumination effectively modulates a single object image (eg, of a pattern or defect) with an envelope such as a Gaussian distribution. This reduces the first-order diffraction contrast and consequently, compared to monochromatic illumination, which causes the image to contain more than the first-order diffraction contrast.
Improve overall image contrast or system resolution. For this reason, most current methods and systems for wafer inspection and metrology systems involve the use of broadband white illumination of the wafer.

[0010]

There are several important limitations to currently employed wafer illumination methods and systems used in optical microscope wafer inspection and metrology systems. The critical dimensions of current wafers are about 180 nm, but normal analysis of wafer structures is less than about 90 nm for defect detection, less than about 20 nm for metrology, and 10 nm for optical overlay applications. Has also become. To date, methods and systems including broadband white illumination used in wafer inspection systems have been suitable for obtaining high quality and high system resolution images. However, as wafer inspection and metrology techniques have advanced, critical dimensions have further decreased, making it more difficult to maintain high resolution and system resolution of single object or structure images using broadband white illumination of the wafer. It has become. Therefore, the illumination methods and systems used in optical microscope wafer inspection and metrology systems necessarily move from those based on broadband white illumination to wafer illumination of lower wavelength, higher energy light sources such as UV light illumination. There is a need to. Therefore, it is necessary and useful to have an illumination method and system for use in an optical microscope wafer inspection and metrology system based on UV light illumination.

With respect to illumination methods and systems involving the use of UV light sources, further limitations need to be overcome. For example, the image resolution of a single object or structure can be higher (e.g., by using a broadband white light source (e.g., characterized by a spectrum having a broadband wavelength range of This is greatly increased by the use of a monochromatic UV light source (characterized by the narrow band wavelength range of 360 nm to 370 nm used in the present invention). However, the diffraction effect simultaneously increases with increasing energy of the illumination light source, such as a monochromatic UV light source, resulting in the generation of noise in the data of the wafer image, thereby causing a decrease in system resolution. This phenomenon is particularly pronounced on wafers characterized by multiple defects and patterns in close proximity to each other. Commonly used methods of eliminating or minimizing diffraction effects cannot be directly applied to current wafer inspection or metrology systems using monochromatic UV light sources. For example, interference techniques may be available, but they are very slow and have low throughput and are complex to implement.
Furthermore, image processing techniques that eliminate diffraction rings from images are not practical for application to optical microscope wafer inspection or metrology systems.

An ideal method and system for wafer illumination for use in an optical microscope wafer inspection or metrology system is to use broadband UV illumination of the wafer, which is characterized by the use of a broadband UV light source having a spectral range of 250 nm-500 nm, for example. including. Such a broadband UV light source allows for efficient modulation of a single object or structure with an envelope such as a Gaussian distribution. Unfortunately, although broadband UV light sources are theoretically possible, they are not currently in practical use. Known UV light sources (eg, mercury arc lamps) provide narrow band monochromatic spectra (eg, 3
60-370 nm, 398-407 nm, etc.).

A very close approximation of an ideal broadband UV light source uses multiple bands or wavelengths of known UV light sources for wafer illumination. In this case, the resolution of the single object or structure is better than the resolution of the method including white light illumination, and the simultaneously occurring diffraction effect is higher than the resolution observed in the image obtained by employing the method including the monochromatic UV light source. small. Thus, a method and system for multi-band UV light illumination for use in an optical microscope wafer inspection and metrology system is needed and useful. Further, such a method and system of wafer illumination that is technically adaptable, cost-effective and durable for continued adoption in a wafer manufacturing environment in addition to a wafer research or development environment. Is necessary and useful.

[0014]

SUMMARY OF THE INVENTION The present invention relates to an illumination method and system used in an optical microscope applied to a wafer inspection and measurement system, and more particularly to a method for illuminating a wafer used in an optical microscope wafer inspection and measurement system. It relates to a method and system for multi-band UV light illumination.

The method and system for multi-band UV light illumination of the present invention are 360-370 nm and 398-407 nm.
Using a UV light source (eg, a mercury arc lamp) that produces a multi-wavelength UV light source having a UV light illumination spectrum having two narrow band regions and a visible light illumination spectrum having a single narrow band region of 427/434 nm. It is characterized by. Further, the method and system of the present invention include a broadband objective system that passes multi-band UV light through a broadband UV illumination path and collects the reflection and scatter of the image from the wafer surface, and optically controls the reflection and scatter of the image. Provide, but are not limited to, a wafer inspection and metrology system having an optical system that includes a broadband tube lens for focusing on a sensitive camera surface. In addition, specially written data processing algorithms can be used to process wafer images obtained using the methods and systems of the present invention.

The use of the optical microscope wafer inspection and metrology system of the present invention in a method and system for multi-band UV light illumination of a wafer requires a single object or structure as compared to the method and system featuring broadband white light illumination. Significant measurable improvement in the resolution of the wafer and significant measurement of the overall system resolution of the wafer image without causing radiative damage to the wafer compared to methods and systems featuring monochromatic UV light illumination Bring as much improvement as possible. The methods and systems of the present invention are directly applicable to wafer manufacturing environments, including applications to quality control systems used at various stages of wafer manufacturing. Improvements in system resolution of wafer images are very important to the technological advances that are currently taking place in wafer development and manufacturing in the semiconductor industry.

Multiband UV of Wafer to which Optical Microscope Wafer Inspection and Measurement System of the Present Invention is Applied
A preferred embodiment of the method of light illumination is characterized by the following main steps. The main steps include (1) (a) providing an optical microscope with a broadband objective system, and (b) initializing the optical microscope system for wafer inspection and metrology, including selecting a broadband objective system with the desired magnification. (2) (a) with initial UV light source filtering either by broadband filtering or individual band filtering;
Optimization of optical microscopes for wafer inspection or metrology, including generation of multi-band UV light spectra according to special wafer inspection or metrology applications;
(3) illumination of the wafer with an optimized multi-band UV light source, (4) (a) collection of image reflection and scattering of multi-band UV light from the wafer surface via a broadband objective system, (b) broadband tube Image of the wafer including convergence of image reflection and scattering through the lens to an optically sensitive camera surface, (c) digitization of the light intensity distribution, and (d) storage of the digitized light intensity distribution. And (5) the application of special algorithms to process the digitized wafer image, and (b) the digitalization of the light intensity according to the desired application, including the display and use of the analysis results of the wafer surface. Image processing of the localized distribution.

Multiband UV of Wafer to Which Optical Microscope Wafer Inspection and Measurement System of the Present Invention is Applied
A preferred embodiment of the system for light illumination is characterized by the following main elements: The key elements are: (1) an optical microscope featuring a broadband objective system, a broadband illumination path, and a broadband tube lens; (2) the first ultraviolet light source that is part of an optical microscope wafer inspection and metrology system; (3) An apparatus that performs broadband filtering or individual band filtering of the first UV light source to generate a multi-band UV light source from the first UV light source, and (4) a wafer illuminated using the multi-band UV light source. An additional element of the preferred embodiment of the system of the present invention is (5) a camera surface having optical sensitivity to receive focused image reflection and scattering of multi-band UV light from the wafer surface via a broadband tube lens. And (6) a data processing apparatus for digitizing the distribution of light intensity characteristics on the wafer surface, storing the digitized light intensity distribution, and processing the stored digitized light intensity distribution. The data processing equipment used to process the stored digitized distribution of the light intensity characteristics of the wafer surface uses special algorithms for wafer defect detection, wafer overlay measurement, and wafer critical dimension measurement. It is a feature, but is not limited to this.

According to the present invention, there is provided a method of multi-band UV light illumination of a wafer for an optical microscope wafer inspection and metrology system, the method comprising: (a) a broadband objective system, a broadband illumination path;
Providing an optical microscope featuring a broadband tube lens; (b) positioning the wafer in a sample holder of the optical microscope; (c) activating a first ultraviolet light source that is part of the optical microscope system. (D) generating a multi-band UV light source from the first UV light source, (e) positioning the wafer in the focal plane of the broadband objective system, (f).
Illuminating the wafer using a multi-band UV light source; (g) imaging the wafer using the multi-band UV light source; (h) data processing the image of the wafer; Displaying and using the results of the data processed image.

In accordance with the present invention, there is provided a system for multi-band UV light illumination of a wafer for an optical microscope wafer inspection and metrology system, the system comprising:
(A) an optical microscope featuring a broadband objective system, a broadband illumination path, and a broadband tube lens; (b) a first ultraviolet light source that is part of the optical microscope system; (c) a multiband UV from the first UV light source. A device for generating a light source, and (d) a multi-band U
A wafer is illuminated using a V light source.

According to the present invention, there is provided a method of generating a multi-band UV light source of illumination for optical microscope inspection and metrology of a wafer, comprising: (a) a broadband objective system, a broadband illumination path, and a broadband illumination; Providing an optical microscope featuring a tube lens, (b) positioning the wafer in a sample holder of the optical microscope, (c) initial UV
Sending the UV light of the light source into a broadband UV illumination path; and (d) first UV by means selected to generate a multi-band UV light source of illumination from a group consisting of broadband filtering and individual band filtering. Filtering the UV light of the light source so that the multi-band UV light source of the illumination features multi-band UV light.

Employing the method of the present invention includes performing or completing a task or step manually, automatically, or a combination thereof. Furthermore, depending on the actual implementation and equipment of a given wafer inspection system, some of the steps of the present invention can be implemented by hardware or software on any firmware operating system or a combination thereof. For example, if implemented in hardware, the above steps of the present invention would include:
It can be realized as a chip or a circuit. If implemented in software, the above steps of the invention could be implemented as a plurality of software instructions executed by a computer using a suitable operating system.
In any case, the above steps of the method of the present invention can be described as being performed by a data processor, such as a computing platform that executes a plurality of instructions.

[0023]

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method and system for multi-band UV light illumination of a wafer for an optical microscope wafer inspection and metrology system. The steps and implementation of the method of multi-band UV light illumination of a wafer for the optical microscope wafer inspection and metrology system of the present invention will be better understood with reference to the drawings and accompanying description. The description of the invention provided herein is for illustrative purposes only and is not intended to limit the invention. For example, the following figures and accompanying description of a preferred embodiment of the method of the present invention illustrate two bands in the UV spectrum (ie, 360-370 nm and 39
(8-407 nm) and one band in the visible spectrum (i.e., 427-434 nm). Another example of the method of the invention is
It may feature more than two bands of illumination light sources in the UV spectrum and more than one illumination light source in the visible spectrum.

Here, reference is made to the drawings. FIG. 1 is a flow diagram of a preferred embodiment of a method for multi-band UV light illumination of a wafer for an optical microscope wafer inspection and metrology system of the present invention. In FIG. 1, the principle steps of the method of the invention, each generally applicable, are numbered and are inside a frame. Sub-steps further denoting the indicated principle steps of the method are indicated by letters in parentheses. The terms that appear in the following description
Matches the one used in

In step 1, the optical microscope for wafer inspection is initialized. In step (a), an optical microscope with a broadband objective system and a broadband UV illumination path is provided.
In step (b), a broadband objective system featuring a desired magnification range is selected for an optical microscope. In step (c), the broadband objective system is adjusted and set according to the application of the wafer inspection. In step (d), the wafer is placed on a sample holder (chuck). In step (e),
A multi-band UV light source (eg, a mercury arc lamp, preferably characterized by low pressure, preferably a mixture of mercury vapor and a noble gas) is turned on. In step (f), the first UV light source is sent through the broadband UV illumination path of the installed optical microscope.

In step 2, optimization of the installed optical microscope for wafer inspection is performed. The first multi-band UV light source features UV light in the UV spectrum in addition to white light in the visible spectrum, such as the wavelength filtering typically required to establish a light source of the desired spectrum. In step (a), a multi-band UV light spectrum is established according to the wafer inspection application by filtering the first UV light source either by broadband filtering or individual band filtering. Broadband UV light filtering is used instead of monochromatic UV light filtering. In a preferred embodiment of the method of the present invention, the multi-band UV light source has two bands in the UV spectrum (ie, 360-370 nm and 3 bands).
98-407 nm) and one band in the visible spectrum (i.e., 427-434 nm). Another preferred embodiment of the method of the invention features more than two bands of the illumination source in the UV spectrum and more than one band of the illumination source in the visible spectrum. In step (b), attenuation of the filtered multi-wavelength UV light source is performed. In step (c), a filtered multi-band UV light source is positioned, focused and oriented on the wafer sample. In step (d), the wafer is placed in the focal plane of the broadband objective system.

In step 3, the wafer is illuminated by the optimized filtered multi-band UV light source. In step (a), a filtered multi-wavelength UV light source is sent through a broadband objective system. In step (b), the energy level of the UV mercury lamp is set according to the application of the wafer inspection. In step (c), the wafer surface is illuminated with a filtered multi-band UV light source.

In step 4, the wafer is imaged. In step (a), the image reflection and scatter of filtered multi-band UV light from the wafer surface is collected via a broadband objective system. In step (b), image reflection and scatter are converged via a broadband tube lens to an optically sensitive camera surface. The camera surface receives a distribution of light intensity from the wafer surface. In step (c), the intensity distribution is digitized. In step (d), the intensity distribution is stored in a memory of the image processor.

In step 5, the stored digital light intensity distribution is imaged into a wafer image according to the desired wafer inspection application. In step (a), a special image processing algorithm is applied to the processing of the digital wafer image. Defect detection algorithms are an example of a category of special image processing algorithms commonly used in wafer inspection systems. One common and widely used defect detection algorithm is based on comparing wafer image data obtained from images of two adjacent regions of the same wafer. For example, an image of a first region of a specific pattern on a predetermined wafer is used as a first reference image. An image of a second region featuring the same specific pattern and containing a defect is used as the second sample image. In this step, defects are detected by directly subtracting the first reference image from the second sample image. The use of this type of direct detection algorithm sets the detection threshold level of the image signal (brightness or intensity of the pixel measured at the gradation level) in order to prevent erroneous detection of the image signal due to the diffraction effect. The threshold level is the level of brightness or intensity of a pixel measured at a gray level, and data points above that level (ie, above the diffraction level of a given wafer area) are used for subsequent image processing. The following data points are not used for further image processing. The use of this defect detection algorithm in the preferred embodiment of the method of the present invention applied to an optical microscope wafer inspection system allows (for example) to set lower thresholds during processing of the resulting image data. Using this algorithm in a method featuring broadband white light illumination or monochromatic UV light illumination of the wafer results in a noticeable and measurable improvement in system resolution, equivalent to a higher sensitivity of defect detection.

In step (b), the results of the processed wafer image are displayed on a display for wafer surface analysis and characterization. Examples of using the method of multi-band UV light illumination of wafers for optical microscope wafer inspection and metrology systems include broadband white light illumination, monochromatic UV
Optical microscopy inspection or metrology using the methods of light illumination and multi-band UV light illumination separately, is shown by computational simulations with a bench of figures of a sample wafer characterizing patterns and defects. A further discussion of the method of the present invention is that the image intensity or pixel brightness (for pixel numbers at some specified traverses of the pixel grid of the image shown in the sample wafer diagram and the computational simulation image). Includes analysis of digital wafer images with plots for comparison of gray levels.

FIG. 2 is a diagram of the actual arrangement of samples of patterns and defects on the surface of a wafer on a laboratory bench for optical microscope inspection or measurement. In FIG. 2, typical patterns appearing on the wafer are indicated by reference numerals 12, 14, 1
6, typical defects are indicated by reference numerals 18, 20, 2
Indicated at 2, 24. Patterns 12, 14, and 16
They have critical dimensions of 200 nm, 50 nm and 50 nm, respectively. The left and right sides of the pattern 12 are indicated by reference numerals 12a and 12b, respectively, and the central empty part is 12c.
Indicated by Defects 18, 20, 22, and 24 have critical dimensions of 100 nm, 50 nm, 200 nm, and 100 nm, respectively. Other areas of the wafer surface that are relatively far away from the patterns 12, 14 and 16 and the defects 18, 20, 22 and 24 are designated by the reference numerals 26 and 28. The reference numeral 10 in FIG. 2 represents the field of view of the sample of the optical microscope used for application of the method of the invention (for example 6.5 μm).
m), which is a portion surrounded by a sample wafer frame. Grid lines corresponding to rows (rows) or columns (columns) include broken lines 30 (row 13), 32 (row 32),
Represented by 34 (row 53) and 36 (column 21), they are included in the figure to refer to the location of pixels in designated patterns, defects and other areas of the wafer surface. The ideal grid lines were generated using the following computer-based method of the sample wafer shown in FIG. 2 to compare the results using the method of the present invention with the results obtained using broadband white light illumination or monochromatic UV light illumination. Included in the simulated image.

FIGS. 3 to 5 show an original image of the sample of the wafer 10 of FIG. 2 using broadband white light illumination (400-600 nm),
By simulating for optical microscope inspection or measurement using monochromatic UV light illumination (360-370nm) and multi-band UV light illumination (including 360-370nm, 400-600nm and visible band 427-434nm) methods respectively. 4 shows an obtained simulation image. The simulation images calculated in these simulations are:
This was done using an optical microscope simulator algorithm, using the input of a diagram of a sample original image of the wafer 10 (of FIG. 2). The simulator algorithm simulated the function and performance of an ideal optical microscope, ignoring aberration effects. The simulator algorithm is based on a physical model of an ideal lens with a cut-off filter in the back aperture. In the simulator algorithm, the back aperture operates according to the values of the two main parameters entered in the algorithm. The two main parameters are the numerical aperture (NA, e.g., 0.9, and are kept constant when generating simulated images for each of the above three methods of wafer illumination) and the illumination applied. Spectrum (ie, e.g., 400-600)
nm broadband white light illumination, 360-370 nm
Monochromatic UV light illumination, or 360-370 nm and 398-
Multi-band UV illumination including 407 nm and visible bands 427-434 nm). The operation of the ideal lens is mathematically described by a Fourier transform between the image in the focal plane and the image in the back aperture plane. The image in the back aperture plane is a Fourier transform of the image in the focal plane. The mathematical equation describing this process is described in the reference text "Principles of Optics: Electromagnetic Theory o
f Propagation, Interference and Diffraction of Lig
ht ", 6th edition, Born, Max, and Wolf, Emil, Cambr
Shown in idge University Press, 1998. (Of FIG. 2)
The illustration of the input original image of the wafer 10 is converted by a simulated optical microscope into a light intensity distribution at the focal plane of the objective lens. Throughout the simulation, this image is first sent through a first ideal lens, then through a rear aperture cutoff filter, and then through a second ideal tube lens, where image magnification occurs. The output image is detected as a light intensity distribution by a camera, and the camera detects the amplitude of the electromagnetic field.

In the simulation images shown in FIGS. 3 to 5, the size of the field of view of each output image obtained from the simulation is 6.5 μm. Pixel size (size) in the simulated output image
Is 0.1 μm, that is, the size of one pixel = 100 nm in the sample wafer 10 used for the simulation. The pixel amplitude or intensity is expressed in terms of brightness gradation level, and the dynamic range is from 0 to 255 gradation levels. The numerical aperture of the simulated optical microscope is constant when generating simulated images for each of the above three methods of wafer illumination (eg, N
A = 0.9). The differences in amplitude or pixel brightness appearing in the simulated image represent the actual differences obtained using the above method of wafer illumination, are not random, and are not generated using simulator algorithms. The information obtained at or near the edge of the field of view of the sample wafer 10 corresponds to or near the edge region described below in the simulation image and is considered to be unrelated to the discussion of the method of the present invention. Graphical quantitative analysis shown and compared in each of FIGS. 6-9 is provided for FIGS. 3-5.

FIG. 3 shows a simulation image 3 obtained by simulating an optical microscope inspection or measurement using the sample wafer 10 of FIG. 2 as an experimental table and using a method of broadband white illumination (400-600 nm).
8a is shown. The patterns 12, 1 of the sample wafer 10 of FIG.
4 and 16, defects 18, 20, 22 and 24, other wafer surface areas 26 and 28, and pixel grid lines 30 (row 13), 32 (row 30), 34 (row 53) and 36 (column 21) 3, the patterns 40a, 42a and 44
a, defects 46a, 48a, 50a and 52a, other wafer surface areas 54a and 56a, and pixel grid lines 60
(Line 13), 62 (line 30), 64 (line 53) and 66
(Column 21).

The salient points of FIG. 3 are as follows. Patterns 40a, 42a and 44a, and defects 46a and 48
The image resolution of a, 50a and 52a (i.e. not the system resolution) is the corresponding pattern 12, 14, and 16 of the original image 10 of FIG.
0, 22 and 24 are relatively inferior. Pattern 40
The side part and the central empty part of a are basically not separated from each other. Furthermore, the cross section of the pattern 42a, and the two bottoms and one upper left extension of the pattern 44a, together with the center, are essentially not disassembled. However, the uniformity and value of pixel brightness gradation levels at pixel locations away from the pattern and edges (eg,> 200 nm) of the simulated image 38a, eg, at the other wafer surface regions 54a and 56a, may be due to broadband white light illumination. Sources and patterns 40a, 42a and 44a or defects 46a, 48a, 5
Shows the minimum diffraction effect caused by the interaction between Oa and 52a. Minimal diffraction effects are due to light microscopy (FIG. 2) using the method of broadband white light illumination.
It can be transferred to a high system resolution of inspection and measurement of the surface of the sample wafer 10.

FIG. 4 shows a simulation image 38b obtained by simulating by optical microscope inspection or measurement using the method of monochromatic UV light illumination (360-370 nm) using the sample wafer 10 of FIG. 2 as an experimental table. . The patterns 12, 14 and 1 of the sample wafer 10 of FIG.
6, defects 18, 20, 22 and 24, other wafer surface areas 26 and 28, and pixel grid lines 30 (row 13);
32 (row 30), 34 (row 53) and 36 (column 21)
4, in FIG. 4, patterns 40b, 42b and 44b, defects 46b, 48b, 50b and 52b, other wafer surface areas 54b and 56b, and pixel grid lines 70 (row 1).
3), 72 (row 30), 74 (row 53) and 76 (column 2)
1).

The salient points of FIG. 4 are as follows. Patterns 40b, 42b and 44b, and defects 46b and 48
The image resolution (ie, not the system resolution) of b, 50b, and 52b is the corresponding pattern 12, 14, and 16 of the sample wafer 10 of FIG.
8, 20, 22 and 24, the corresponding patterns 40a, 42a and 44 of the simulation image 38a
a and the image resolution of the defects 46a, 48a, 50a and 52a is much better. Pattern 42b
Side and the central empty part are separated from each other. Further, the image resolution of the cross section of the pattern 42b, the two bottoms and one upper left extension of the pattern 44b, together with the center, are shown in FIG.
2) is much higher than the image resolution of the corresponding pattern element shown in the simulation image 38a of the sample wafer 10 using the broadband white light illumination.

However, the simulation image 38
a, pixel positions further (eg,> 200 nm) away from the edge of the pattern or defect in the simulated image 38b, eg, other wafer surface areas 54b and 56b
The remarkable fluctuation of the pixel brightness gradation level at
It shows significant diffraction effects caused by the interaction between the V light illumination source and the patterns 40b, 42b and 44b or the defects 46b, 48b, 50b and 52b. The noticeable diffraction effect that is noticeable in the simulation image 38b, as compared to the minimal diffraction effect that appears in the simulation image 38a, is due to the optical microscope using the method of monochromatic UV light illumination, as compared to using the method of broadband white light illumination. (Figure 2
(1) The inspection and measurement of the surface of the sample wafer 10 have very low system resolution.

FIG. 5 shows a multi-band UV light illumination (360-370 nm, 398-407 nm, 427-μm) using the sample wafer 10 of FIG.
434 nm), showing a simulated image 38c obtained by simulating with optical microscope inspection or measurement. Sample wafer 10 of FIG.
Patterns 12, 14 and 16, defects 18, 20, 22
And 24, the other wafer surface areas 26 and 28, and the pixel grid lines 30 (row 13), 32 (row 30), 34 (row 53) and 36 (column 21) in FIG.
c, 42c and 44c, defects 46c, 48c, 50c and 52c, other wafer surface areas 54c and 56c, and pixel grid lines 80 (row 13), 82 (row 30), 84
(Rows 53) and 86 (column 21).

The salient points of FIG. 5 are as follows. Patterns 40c, 42c and 44c, and defects 46c and 48
The image resolution of c, 50c and 52c (ie, not the system resolution) is the corresponding pattern 12, 14 and 16 and the corresponding defect 1 of the sample wafer 10 of FIG.
8, 20, 22 and 24, the corresponding patterns 40a, 42a and 44 of the simulation image 38a
a and the image resolution of the defects 46a, 48a, 50a and 52a is much better. Pattern 42c
The sides and the central empty part are basically decomposed from each other. In addition, the image resolution of the cross section of the pattern 42c, the two bottoms and one upper left extension of the pattern 44c, together with the center, provide a simulation image 38a of the sample wafer 10 (of FIG. 2) using broadband white light illumination.
Compared to the image resolution of the corresponding pattern element shown in
It is very high.

Simulation image 38b featuring monochromatic UV light illumination of sample wafer 10 with pattern image and defect image resolution (ie, not system resolution) of simulation image 38c featuring multi-band UV illumination of sample wafer 10. For comparison of the image resolution of the pattern and the defect, the multi-band U
The image resolution obtained using the method featuring V illumination is comparable to that obtained using the method featuring monochromatic UV light illumination of the sample wafer 10.

Regarding the presence of diffraction effects in the simulated image 38c obtained by employing the method featuring multi-band UV illumination according to the present invention, the distance away from the edge of the pattern or defect (eg> 200 nm)
Pixel locations, such as other wafer surface areas 54c and 56
The variation of the pixel brightness gradation level at c is not minimal, as is the variation in the pixel brightness gradation level that appears in the simulated image 38a of the method featuring broadband white light illumination, but the monochromatic UV of the sample wafer 10. Much less than the variation that appears in the simulation image 38b of the method featuring light illumination. The method using multi-band UV illumination allows for an effective modulation of sample wafer patterns and defects with a Gaussian distribution, such as an envelope, thereby comparing with methods using monochromatic UV light illumination. Reduce the interference diffraction effect. By transferring some of the diffraction effects to an optical microscope wafer inspection or metrology system, higher resolution can be achieved with methods featuring multi-band UV light illumination than methods featuring monochromatic UV light illumination. This allows for the detection, resolution and measurement of wafer defects and patterns and their accuracy as compared to using monochromatic UV light illumination, using a method featuring multi-band UV light illumination of the wafer. Indicates a possibility.

FIGS. 6 to 9 show plots of the image amplitude with respect to the pixel number, that is, the brightness (gradation) of the pixel, and the plots are the simulation images 38a, 38b and 38c of FIGS. 2 correspond to different transverse lines of either the rows or the columns of the image grid shown in the sample wafer 10 of FIG. The data and information contained in FIGS. 6-9 are based on the image resolution, diffraction effects, and system resolution described by the discussion of FIGS. 3-5 of different methods of illuminating wafers for application to optical microscope wafer inspection and metrology systems. The results and conclusions related to the comparison of are further quantified.

FIG. 6 shows the image amplitude or pixel brightness (gray level) corresponding to the transverse line of row 13 of the image grid shown in the sample wafer 10 of FIG. 2 in the simulation images of FIGS. Is plotted against the pixel number. In FIG. 6, curves 90, 92 and 94
Corresponds to the application of the method characterized by the use of broadband white light wafer illumination, monochromatic UV light wafer illumination, and multiple UV light wafer illumination, respectively (reference numeral 3 in FIG. 2).
0, simulation images 38a, 38b, 3
8c plotted from left to right along the traversal of row 13 of the pixel grid (represented by reference numerals 60, 70, and 80, respectively), at the gray level, in units of image amplitude or pixel brightness versus pixel number. is there. All curves 9
For 0, 92 and 94, the sharp decrease in pixel brightness at pixel numbers less than 5 indicates a diffraction effect that occurs at the edge of the field of view of the sample wafer 10 of FIG. It has nothing to do with the discussion of differences in image resolution, diffraction effects or system resolution.

The salient points of FIG. 6 are as follows. The pattern 1 of FIG. 2 corresponding to the patterns 40b and 40c of the simulation images 38b and 38c of FIGS. 4 and 5, respectively.
2. The excellent image resolution of the sides 12a and 12b of the pattern and the center 12c of the pattern is due to the pixel number between 25 and 30 along the curves 92 and 94 for each method of monochromatic and multi-band UV light illumination. At 96a and 96b
And the maximum 96c. The poor image resolution of the pattern 12, pattern sides 12a and 12b and pattern center 12c of FIG. 2, corresponding to pattern 40a of the simulated image 38a of FIG. 4, is between 27 and 30 along the broadband white light illumination curve 90. And is clearly indicated by 96d. Further, the image resolution obtained by simulation of the method featuring the use of multi-band UV light illumination is shown by curve 94 and obtained by simulation of the method featuring the use of monochromatic UV light illumination, shown by curve 92. It is almost the same as the image resolution.

For a comparison of the diffraction effects due to the interaction between the illumination light source and the pattern or defect on the sample wafer 10 of FIG. 2, regions 98 and 100 of FIG.
4 obtained using the method of light illumination and multi-band UV light illumination (ie, defects 46b, 48b, 50b when viewed from left to right along row 13 at 70). And 52b, and pattern 4
0b and the wafer surface 54b), and FIG.
Simulation image 38c (that is, reference numeral 8)
Defect 46 when viewed from left to right along row 13 indicated by 0
c, 48c, 50c and 52c, and the edge areas of the pattern 40c, and the curves 92 and 94 corresponding to the wafer surface 54c), respectively, are obtained using the method of broadband white light illumination, respectively, in the simulation image of FIG. Curve 90 corresponding to 38a (i.e., defects 46a, 48a, 50a and 52a, and the edge area of pattern 40a and wafer surface 54a when viewed from left to right along row 13 indicated by reference numeral 60). In comparison, there is a noticeable variation in the brightness of the pixels. However, the variation in pixel brightness indicated by curve 94 corresponding to multi-band UV light illumination (FIG. 5) is greater than the variation in pixel brightness indicated by curve 92 corresponding to monochromatic UV light illumination (FIG. 4). Very little. This result is shown in FIG.
Consistent with the discussion of US Pat.
Achieved in a manner featuring light illumination.

FIG. 7 shows the image amplitude or pixel brightness (gray level) corresponding to the transverse line of row 30 of the image grid shown in the sample wafer 10 of FIG. 2 in the simulated images of FIGS. Is plotted against the pixel number. In FIG. 7, curves 110, 112 and 114 are broadband white light wafer illumination, monochromatic UV
It corresponds to an application of the method characterized by the use of optical wafer illumination and the use of multiple UV light wafer illumination, respectively (represented by reference numeral 32 in FIG. 2 and simulation images 38a, 38).
b, 38c (represented by reference numerals 62, 72, 82, respectively) along the traversal of row 30 of the pixel grid, from left to right, relative to the pixel number of the image amplitude or pixel brightness in grayscale levels. It is a plot. For all curves 110, 112 and 114, the sharp decrease in pixel brightness at pixel numbers less than 5 indicates a diffraction effect that occurs at the edge of the field of view of the sample wafer 10 of FIG. It has nothing to do with the discussion of differences in image resolution, diffraction effects or system resolution within the method.

The salient points of FIG. 7 are as follows. The patterns 14 of FIG. 2 corresponding to the patterns 42b and 42c of the simulation images 38b and 38c of FIGS. 4 and 5, respectively.
The image resolution of the pattern 14 of FIG. 2 corresponding to the pattern 42a of the simulated image of FIG. 3 for the same region of the pixel number along the curve 110 of the method of broadband white light illumination is monochromatic This is clearly indicated by minimum areas 116 and 118 at pixel numbers between 12 and 30 along curves 112 and 114 for the UV light illumination and multi-band UV light illumination methods.
Further, the image resolution obtained by simulation of the method featuring the use of multi-band UV light illumination is shown by curve 114 and is obtained by simulation of the method featuring the use of monochromatic UV light illumination, shown by curve 92. It is almost the same as the image resolution. For a comparison of the diffraction effects due to the interaction between the illumination source and the pattern or defect on the sample wafer 10 of FIG.
4 are obtained using the method of monochromatic UV light illumination and the method of multi-band UV light illumination, respectively (i.e., row 30 indicated by reference numeral 72).
Defects 50b and 52b when viewed from left to right along
And the edge areas of the patterns 40b, 42b and 44b) and the simulation image 38c of FIG. 5 (ie, the defects 50c and 52c and the pattern 40c when viewed from left to right along the row 30 indicated by reference numeral 82). 4
Curves 11 corresponding to the edge areas 2c and 44c)
2 and 114 are respectively the simulation images 38a of FIG. 3 obtained using the method of broadband white light illumination.
(I.e., the defects 50a and 52a and the pattern 4 when viewed from left to right along the row 30 indicated by reference numeral 62)
0a, 42a, 44a edge area and wafer surface 5
As compared with the curve 110 corresponding to 4a), only a gradual change in the brightness of the pixel is shown.

FIG. 8 shows the image amplitude or pixel brightness (gray level) corresponding to the traversing line of the row 21 of the image grid shown in the sample wafer 10 of FIG. 2 in the simulation images of FIGS. Is plotted against the pixel number. 8, curves 130, 132 and 134 represent broadband white light wafer illumination, monochromatic UV.
It corresponds to an application of the method characterized by the use of optical wafer illumination and the use of multiple UV light wafer illumination, respectively (represented by reference numeral 36 in FIG. 2 and simulation images 38a, 38).
b, 38c (represented by reference numerals 66, 76, 86, respectively) from top to bottom along the transverse line of column 21 of the pixel grid, relative to the pixel number of the image amplitude or pixel brightness in units of gray level. It is a plot. All curves 13
For 0, 132 and 134, the sharp decrease in pixel brightness at pixel numbers less than 4 is shown in sample wafer 1 of FIG.
It shows the diffraction effect that occurs at the edge of the zero field of view and is irrelevant to the discussion of differences in image resolution, diffraction effect or system resolution within different methods of light illumination of the wafer.

The salient points of FIG. 8 are as follows. The patterns 14 of FIG. 2 corresponding to the patterns 42b and 42c of the simulation images 38b and 38c of FIGS. 4 and 5, respectively.
The very high image resolution of the pattern 42 of the simulated image 38a of FIG. 3 for the same area of pixel numbers along the curve 130 of the broadband white light illumination method
2, the minimum area at pixel numbers between 28 and 35 along the curves 132 and 134 for the monochromatic and multi-band UV light illumination methods, respectively, compared to the image resolution of the pattern 14 of FIG. 136. Furthermore, the image resolution obtained by the simulation of the method characterized by the use of multi-band UV light illumination gives a monochromatic UV
The image resolution obtained by simulation of the method characterized by the use of light illumination, which is almost the same as the minimum area 136. Thus, the image resolution of the pattern on the sample wafer 10 of FIG. 2 is improved by employing the multi-band UV light illumination method of the present invention, as compared to employing the broadband white light illumination method. It was shown again.

For a comparison of the diffraction effects due to the interaction between the illumination light source and the pattern or defect on the sample wafer 10 of FIG. 2, regions 140 and 142 of FIG.
The simulated image 38b of FIG. 4 (ie, defects 46b, 48b when viewed from top to bottom along column 21 indicated by reference numeral 76) obtained using the methods of V-light illumination and multi-band UV light illumination, respectively. , 50b and 52b, and the edge areas of the patterns 40b, 42b and 44b) and the simulated image 38c of FIG. 5 (i.e., the defects 46c and 48c as viewed from top to bottom along column 21 indicated by reference numeral 86). , 50c and 52c, and pattern 4
Curves 132 and 134, corresponding to the edge areas of Oc, 42c, and 44c, and the wafer surface area 56), respectively, are obtained using the method of broadband white light illumination. Defects 46a, 48a, 50a and 52a, and pattern 40 as viewed from top to bottom along column 21 designated by reference numeral 66.
Only the significant variations in the brightness of the pixels are shown, as compared to the curves 130 corresponding to the edge regions a, 42a, 44a and the wafer surface region 56a). However, the variation in pixel brightness shown by curve 134 corresponding to multi-wavelength UV light illumination (FIG. 4) is much greater than the variation in pixel brightness shown by curve 132 corresponding to monochromatic UV light illumination (FIG. 4). small. This result is consistent with the discussion of FIG. 5, where a higher system resolution results in a monochromatic U
Compared to methods featuring V-light illumination, it is realized in a method featuring multi-band UV light illumination.

FIG. 9 shows the image amplitude or pixel brightness (gray level) corresponding to the transverse line of row 53 of the image grid shown in the sample wafer 10 of FIG. 2 in the simulation images of FIGS. 3 to 5. Is plotted against the pixel number. In FIG. 9, curves 150, 152 and 154 are broadband white light wafer illumination, monochromatic UV.
It corresponds to the application of the method characterized by the use of optical wafer illumination and the use of multiple UV light wafer illumination, respectively (represented by reference numeral 34 in FIG. 2 and simulation images 38a, 38).
b, 38c, denoted by reference numerals 64, 74, 84, respectively, from left to right along the transverse line of row 53 of the pixel grid, relative to the pixel number of the image amplitude or pixel brightness in units of gray level. It is a plot. All curves 15
For 0, 152, and 154, the sharp decrease in pixel brightness at pixel numbers less than 5 is shown in sample wafer 1 of FIG.
It shows the diffraction effect that occurs at the edge of the zero field of view and is irrelevant to the discussion of differences in image resolution, diffraction effect or system resolution within different methods of light illumination of the wafer.

The salient points of FIG. 9 are as follows. There are no patterns or defects along the rows 53 of the pixel grid in the illustration of the sample wafer 10 of FIG. 2 or the simulated images 38a, 38b and 38c (of FIGS. 3, 4 and 5).
Thus, no comparison is made in FIG. 9 relating to the image resolution of the pattern or defect. For a comparison of the diffraction effects due to the interaction between the illumination light source in the range of pixel numbers 7 to 65 and the pattern or defect on the sample wafer 10 of FIG. 2, the method of monochromatic UV light illumination and multi-band UV light illumination 4 (i.e., the bottom edge of pattern 44b and wafer surface area 56b when viewed from left to right along row 53 indicated by reference numeral 74), and FIG. 9 corresponding to the simulation image 38c of FIG. 5 (that is, the bottom edge of the pattern 44c and the wafer surface area 56c when viewed from left to right along the row 53 indicated by reference numeral 84).
Curves 152 and 154 of FIG. 3 are obtained using the method of broadband white light illumination.
8a (i.e., the bottom edge of pattern 44a and the wafer surface area 56a when viewed from left to right along row 53 indicated by reference numeral 64) as compared to curve 150 corresponding to the pixel brightness. High fluctuations. However, curve 1 corresponding to multi-wavelength UV light illumination (FIG. 5)
The variation in pixel brightness indicated by 54 is much smaller than the variation in pixel brightness indicated by curve 152 corresponding to monochromatic UV light illumination (FIG. 4). FIG.
As shown in the discussion of FIG. 8 and the discussion of FIG. 8, this result is consistent with the discussion of FIG. 5, where higher system resolution features multi-band UV light illumination as compared to methods featuring monochromatic UV light illumination. It is realized by the method.

The preferred embodiment of the system for multi-band UV light illumination of a wafer for the optical microscope wafer inspection and metrology system of the present invention is characterized by the following key elements. The key elements are: (1) an optical microscope featuring a broadband objective system, a broadband illumination path, and a broadband tube lens; (2) the first ultraviolet light source that is part of an optical microscope wafer inspection and metrology system; (3) An apparatus that performs broadband filtering or individual band filtering of the first UV light source to generate a multi-band UV light source from the first UV light source, and (4) a wafer illuminated using the multi-band UV light source. An additional element of the preferred embodiment of the system of the present invention is (5) a camera surface having optical sensitivity to receive focused image reflection and scattering of multi-band UV light from the wafer surface via a broadband tube lens. And (6) a data processing apparatus for digitizing the distribution of light intensity characteristics on the wafer surface, storing the digitized light intensity distribution, and processing the stored digitized light intensity distribution. The data processing equipment used to process the stored digitized distribution of the light intensity characteristics of the wafer surface uses special algorithms for wafer defect detection, wafer overlay measurement, and wafer critical dimension measurement. It is a feature, but is not limited to this.

While the invention has been described in connection with specific embodiments thereof, it is evident to those skilled in the art that there are many variations and modifications. Accordingly, such modifications and changes should be considered to fall within the spirit and scope of the appended claims.

[Brief description of the drawings]

FIG. 1 is a flow diagram of a preferred embodiment of a method for multi-band UV light illumination of a wafer for an optical microscope wafer inspection and metrology system of the present invention.

FIG. 2 is an illustration of a sample original image featuring the actual placement of patterns and defects on the surface of a wafer that serves as an experimental bench for optical microscope inspection and measurement.

3 shows a simulation image obtained by simulating the test bench of the sample wafer of FIG. 2 for optical microscope inspection or measurement using the method of broadband white light (400-600 nm) illumination.

FIG. 4 shows a test table of the sample wafer of FIG.
FIG. 10 is a diagram showing a simulation image obtained by simulating an optical microscope inspection or measurement using a method of illumination (70 nm).

FIG. 5 shows a test table of the sample wafer of FIG.
(Including 360-370 nm, 398-407 nm, and visible band 427-434 nm.) FIG. 9 is a diagram showing a simulation image obtained by performing a simulation for an optical microscope inspection or measurement using an illumination method.

6 is a row 1 of an image grid shown in the sample wafer diagram of FIG. 2 in the simulation images of FIGS. 3 to 5;
4 is an illustration of a plot of image amplitude or pixel brightness (gray level) corresponding to a pixel number corresponding to a transverse line of No. 3;

7 is a row 3 of the image grid shown in the sample wafer diagram of FIG. 2 in the simulation images of FIGS. 3 to 5;
5 is an illustration of a plot of image amplitude or pixel brightness (gray level) corresponding to a traverse of 0 with respect to a pixel number.

8 is a column 2 of the image grid shown in the sample wafer diagram of FIG. 2 in the simulation images of FIGS. 3 to 5;
4 is an explanation of a plot of an image amplitude or a pixel brightness (gradation level) corresponding to one transverse line with respect to a pixel number.

FIG. 9 shows rows 5 of the image grid shown in the sample wafer diagram of FIG. 2 in the simulation images of FIGS. 3 to 5;
4 is an illustration of a plot of image amplitude or pixel brightness (gray level) corresponding to a pixel number corresponding to a transverse line of No. 3;

[Description of Signs] 1. Initialization of optical microscope system for wafer inspection and measurement 2. Optimization of optical microscope for wafer inspection and measurement 3. Illumination of wafer by optimization of multi-band UV light source 4. Wafer 5 ... Image processing of stored digitized light intensity distribution on wafer image 12, 14, 16 ... Pattern 18, 20, 22, 24 ... Defect 13, 30, 53 ... Row 21 ... Column

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/66 G01B 11/24 K F

Claims (26)

[Claims] 1. Multi-band ultraviolet (U) light on a wafer for an optical microscope wafer inspection and metrology system.
V) an optical illumination method, comprising: (a) providing an optical microscope characterized by a broadband objective system, a broadband illumination path, and a broadband tube lens; (b) placing the wafer in a sample holder of the optical microscope. (C) activating a first ultraviolet (UV) light source that is part of the optical microscope system; (d) generating a multi-band UV light source from the first UV light source; (e) Locating the wafer in the focal plane of a broadband objective system; (f) illuminating the wafer using the multi-band UV light source; (g) imaging the wafer using the multi-band UV light source (H) data processing the image of the wafer; and (i) the wafer How comprising the step of displaying the results of the data processing images of and use. 2. The method according to claim 1, wherein the steps of providing the light microscope featuring the broadband objective system include: (i) a plurality of magnifications applicable to the light microscope system. Selecting the broadband objective system as follows: and (ii) adjusting and setting the broadband objective system according to the application of the optical microscope system. 3. The method of claim 1, further comprising: sending ultraviolet light of the first UV light source to the broadband illumination path. 4. The method of claim 1, wherein the light band of the multi-band UV light is considered to be monochromatic. 5. The method of claim 1, wherein the step of generating the multi-band UV light source from the first UV light source is by means selected from a group consisting of broadband filtering and individual band filtering. Filtering the UV light of the first UV light source. 6. The method of claim 1, wherein the multi-band UV generated from the first UV light source.
The method wherein the light source comprises bands in the visible light spectrum in addition to multiple bands in the UV light spectrum. 7. The method of claim 1, wherein: (j) attenuating multi-band UV light of the multi-band UV light source; and (k) the multiplex depending on the application of the optical microscope system. A method further comprising locating, converging and directing the multi-band UV light of a band UV light source. 8. The method of claim 1, wherein illuminating the wafer using the multi-band UV light source comprises: (i) multi-band of the multi-band UV light source through the broadband objective system. Sending UV light; and (ii) setting the energy level of the initial UV light source depending on the application of the optical microscope system. 9. The method of claim 1, wherein imaging the wafer using the multi-band UV light spectrum comprises: (i) using the broadband objective system to surface the wafer. Collecting image reflections and scatters of multi-band UV light of said multi-band UV light source coming from; (ii) using said broadband tube lens;
Converging the image reflection and scattering of the multi-band UV light of the multi-band UV light source on an optically sensitive camera surface, wherein the optically sensitive camera surface is a surface of the wafer. Receiving a distribution of light intensity characteristics; (iii) digitizing the distribution of light intensity characteristics on the surface of the wafer to form a digitized distribution of light intensity; and (iv) digitalizing the light intensity. Storing and using the normalized distribution. 10. The method of claim 1, wherein the step of data processing of the image of the wafer comprises a special algorithm for processing a digitized distribution of light intensity characteristics on a surface of the wafer. The method further comprising the step of applying. 11. The method of claim 10, wherein the special algorithm for processing the digitized distribution of light intensity characteristics on the surface of the wafer includes a wafer defect detection algorithm, a wafer optical overlay measurement. And a method selected from the group consisting of an algorithm and a wafer optical critical dimension measurement algorithm. 12. An optical microscope system for multi-band UV light illumination of a wafer for a wafer inspection and metrology system, comprising: (a) a broadband objective system, a broadband illumination path, and a broadband tube lens; (B) a first ultraviolet light source that is part of the optical microscope system; (c) an apparatus for generating a multi-band UV light source from the first UV light source; and (d) illuminating using the multi-band UV light source. A system with a wafer. 13. The system according to claim 12, wherein the light band of the multi-band UV light is considered to be monochromatic. 14. The system of claim 12, wherein the broadband objective system features multiple magnifications applicable to the optical microscope system. 15. The system according to claim 12, wherein the device for generating the multi-band UV light source from the first UV light source is selected from a group consisting of broadband filtering and individual band filtering. system. 16. The system of claim 12, wherein the broadband objective system is characterized by a focal plane on which the wafer is located. 17. The system according to claim 12, wherein the broadband objective system comprises the multiband U.
Used to allow the passage of multi-band UV light of a V light source onto the wafer surface and to collect the image reflection and scattering of the multi-band UV light of the multi-band UV light source from the wafer surface. The system used. 18. The system of claim 12, wherein the broadband tube lens is optically sensitive to image reflection and scattering of multi-band UV light of the multi-band UV light source from the wafer surface. A system for use in focusing on a camera surface, wherein the optically sensitive camera surface receives a distribution of light intensity characteristics of the wafer surface. 19. The system of claim 12, wherein: (e) digitizing a distribution of light intensity characteristics on the wafer surface, storing the digitized light intensity distribution, and storing the stored digital value. A system further comprising a data processing device for processing the light intensity distribution. 20. The system of claim 19, wherein the data processing device for processing the stored digitized light intensity distribution on the wafer surface comprises a wafer defect detection algorithm, a wafer optical overlay measurement algorithm. , And a special algorithm selected from the group consisting of a wafer optical critical dimension measurement algorithm. 21. A method for generating multi-band UV light for illumination for optical microscope inspection and measurement of a wafer, comprising: (a) an optical microscope characterized by a broadband objective system, a broadband illumination path, and a broadband tube lens. Providing; (b) activating a first UV light source that is part of an optical microscope; (c) stepping the UV light of the first UV light source in the broadband illumination path; and (d) broadband filtering. And a group consisting of individual band filtering,
A method comprising filtering UV light of a first UV light source by means selected to produce a multi-band UV light source of illumination characterized by V light. 22. The method of claim 21, wherein the light band of the multi-band UV light is considered to be monochromatic. 23. The method of claim 21, wherein: (e) attenuating the multi-band UV light of the multi-band UV light source of the illumination; and (f) performing the optical microscope inspection and measurement of the wafer. The method further comprising the step of locating, converging and directing the multi-band UV light of the multi-band UV light source of the illumination, depending on the application. 24. The method of claim 21, wherein: (e) sending multi-band UV light of the multi-band UV light source through the broadband objective system; and (f) optical microscopy inspection of the wafer. A method further comprising setting an energy level of said first UV light source depending on a measurement application. 25. The method of claim 21, wherein the multi-band UV generated from the first UV light source.
The method wherein the light source comprises bands in the visible light spectrum in addition to multiple bands in the UV light spectrum. 26. The method of claim 21, wherein the broadband objective system features a plurality of magnifications applicable to optical microscope inspection and metrology of a wafer.