JP2000214099A - Method and apparatus for measurement of crystal defect - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method and an apparatus in which positions or kinds of defects are inspected and displayed easily as a unit and in which the defects are evaluated easily. SOLUTION: When scattered light from a wafer sample is detected, the plane distribution of defects in the wafer sample is obtained as shown in (a). The size-to-depth graph of the defects corresponding to the distribution can be obtained as shown in (b). Since a plurality of kinds (or properties) of the defects are all displayed in (a), it is difficult to intuitively analyze the defects. Then, an operator refers to (b) so as to select, e.g. a group of defects 28 on the graph by using a computer input device such as a mouse. The plane distribution of only the defects in a selected region is displayed instead of (a). Then, the kinds of the defects can be judged intuitively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for measuring crystal defects, and more particularly to a method and an apparatus for measuring crystal defects such as precipitates and stacking faults in a silicon wafer which is a semiconductor wafer.

[0002]

2. Description of the Related Art As the degree of integration of LSIs (Large Scale Integrated Circuits) increases, MOSs (Metal
Oxide semiconductor (Oxide Semiconductor) transistors have a serious problem in that the yield of non-defective products and the decrease in reliability due to transistor failures have become serious problems. Typical causes of the failure of the MOS transistor are dielectric breakdown of the gate oxide film and excessive leakage current at the junction. Many of the defects of these MOS transistors are directly or indirectly caused by crystal defects in the silicon substrate. That is, in the LSI manufacturing process, if a crystal defect exists in the surface region of the silicon substrate which is converted into a silicon oxide film by oxidation, a structural defect is formed in the silicon oxide film, and dielectric breakdown occurs during the operation of the LSI. Also, if a crystal defect exists in the depletion layer of the junction, a large amount of leak current is generated. As described above, if a crystal defect is formed in a surface region where an element is formed in a silicon substrate, a defect of a MOS transistor occurs, which is not preferable.

As described above, defect measurement is important in silicon crystal quality control. In such a method for measuring a defect, it is necessary to be able to measure the entire surface of the silicon wafer and to measure the size of the defect and the depth position of the defect.

[0004] As a conventional measurement technique, as a first known example, a silicon substrate is cleaved, and an infrared ray penetrating a Si crystal is irradiated from a cross-sectional direction (a direction perpendicular to a surface normal direction of a sample) to the silicon substrate. There is a method of taking an image of scattered light from minute defects in a crystal with a camera. This method is called an infrared scattering tomography method and is described in detail, for example, in Journal of Crystal Growth, Vol. 88 (1988), p. However, in this method, it is necessary to cleave the sample, it is impossible to measure the entire surface of the silicon wafer, and the depth resolution is limited to about 1 μm, which is about the wavelength of irradiation light.

As a second known example, Japanese Patent Application Laid-Open No.
At 68, the infrared light is obliquely incident on the sample, and the scattered image from inside the sample is observed two-dimensionally with an infrared camera, so that the depth of each part of the scattered image corresponds to the position in the field of view and the depth of the defect. It describes how to find it. The depth resolution in this case is determined by the optical imaging performance (depth of focus),
Since it is about the product of the wavelength and the refractive index, it is at most 4 μm.

As a third known example, in the conventional method of measuring a defect on the surface of a semiconductor wafer disclosed in Japanese Patent Application Laid-Open No. 6-50902,
The laser light is irradiated on the wafer surface. At this time, the wafer is rotated, and scattered light from the wafer surface is collected by a lens and detected by a detector. A division circuit for each frequency band that divides the obtained detection signal into a high frequency band, an intermediate frequency band, and a low frequency band, a plurality of A / D conversion circuits that digitize each of the divided defect detection signals, and digitization. A plurality of memories are provided for storing the detected defect detection signals as defect data at addresses corresponding to the detection positions of the respective defects. Each of the defect data is processed by the data processing unit, a map is displayed on the printer for each band, and the type of the defect is evaluated based on the defect data displayed on each map. The above method is a method of distinguishing the shape and size of a defect based on the frequency band of a scattered light detection signal generated in a temporally pulsed manner. In the measurement for the purpose of surface foreign matter inspection including this measurement, the size of the surface foreign matter is generally evaluated by the scattered light intensity of one wavelength. When this principle is applied to the internal defect size, there is a problem that even if the defect has the same size, the scattered light intensity is attenuated depending on the depth position of the defect, so that the defect size cannot be evaluated.

As a fourth known example, there is a measurement technique capable of measuring the depth and size of a defect over the entire surface of a silicon wafer. This is Takeda's "Applied Physics" 6th 1996
5, No. 11, page 1162. This is a method of irradiating light of two wavelengths whose penetration depth into a solid is three times or more different by an oblique incidence optical system, and detecting scattered light from a crystal defect in a vertical direction.

The principle is as follows. It is assumed that the second irradiation light has a deeper penetration depth (that is, a longer wavelength) into the Si wafer.

Assuming that the refractive index at a wavelength λ of the sample material (here, Si) is n and the extinction rate is k, the penetration depth at which the amplitude of the incident light becomes 1 / e of the amplitude at the surface is as follows. Given.

Γ = λ / 2πk (1) Therefore, the irradiation light intensity incident on the substance from the air at an incident angle θ is such that, at a depth Z from the surface, the refraction angle in silicon is arcsin (sin θ / n). Given that, exp
((-2Z / Γ) cos (arcsin (sinθ / n)) is attenuated from the surface.

Next, a case is considered in which light is incident on the sample surface from the air at an incident angle θ, and the irradiation light is scattered toward the sample surface due to a defect inside the sample and detected at a certain solid angle. The integrated scattering cross section of the defect for the detected solid angle is σ, the irradiation light intensity is I, the transmittance of the irradiation light at the wafer surface incidence angle is Ti, and the transmittance of the scattered light from the defect from the inside of the wafer to the atmosphere is Ti. Is Ts, the scattered light intensity S from a defect located at a depth Z from the material surface can be expressed as follows in consideration of both the attenuation of the irradiation light and the attenuation of the scattered light.

S = TiTsIσexp [− (2Z / Γ) (1 + 1 / {cos (arcsin (sinθ / n))})] (2) The refractive index of the sample with respect to wavelengths λ1 and λ2 is n1,
n2, penetration depths are Γ1 and Γ2, respectively, and irradiation light intensity is I
1, I2, the measured scattered light intensities are S1 and S2, respectively, the integrated scattering cross sections are σ1 and σ2, the irradiation light transmittance is Ti1 and Ti2, respectively, and the scattered light transmittance is Ts1 and T2, respectively.
If s2, the following equation is established.

S1 = Ti1Ts1I1σ1exp [-(2Z / Γ1) (1 + 1 / {cos (arcsin (sinθ / n1))})]] (3) S2 = Ti2Ts2I2σ2exp [-(2Z / Γ2) (1 + 1 / { cos (arcsin (sinθ / n2))})] (4) Here, Γ1 <Γ2. From equations (3) and (4), Z = C1ln [C2 (S2 / S1) (σ1 / σ2)] (5) where C1 and C2 are the device constant and the optical constant of the sample,
It is defined by the following equation: C1 = 1 / [(2 / Γ1) (1 + 1 / {cos (arcsin (sinθ / n1))})-(2 / Γ2) (1 + 1 / {cos (arcsin (sinθ / n2))}) (6) C2 = (I1 / I2) (Ti1Ts1 / Ti2Ts2) (7) Since C1 and C2 are device constants, if (S2 / S1) (σ1 / σ2) is known, Z can be obtained. Here, (S2 / S1) is a ratio of the signal strength, which is obtained from the measured amount.

Further, the defect size (d) is sufficiently smaller than the irradiation wavelength, and the Rayleigh scattering region (the particle size is 0.2 μm
), Then σ ((d ＾ 6) (λ に つ い て
The relationship of -4) holds, and the relationship of σ1 / σ2 = (λ2 / λ1) ＾ 4 is obtained. By substituting this condition into Equation 5, the following equation is obtained.

Z = C3ln (S2 / S1) + C4 (8) where C3 and C4 are device constants not depending on defects. From the above results, Z is obtained from S1 and S2.

Next, for the defect detected at the wavelength λ1 having the larger absorption coefficient, the particle size of the defect is obtained from the following equation using S2.

Ln (d) = (1/6) ln (S2) + C5 (9) However, for this purpose, the condition of Γ1 << Γ2 is required for the penetration depth of the wavelengths λ1 and λ2. Equation 9 is derived under this condition as follows.

For defects satisfying Z <Γ1 << Γ2,
Since Z / Γ2 (0 can be set in equation (4), S2 = C6σ2. Further, in the Rayleigh scattering region, σ2 (d 成 り 6) holds, so that Expression 9 is obtained.

In the above, ＾ represents a power.

[0020]

The method of measuring crystal defects inside a sample (Si wafer) using infrared rays as in the first and second known examples has a depth resolution of several micrometers. There's a problem. This is because devices in LSI are often formed in a region within 0.5 μm from the silicon surface. When a defect is formed in this region, the device failure rate increases. However, even if a defect occurs in a region deeper than this, the defect is often unrelated to the device failure. Therefore, the depth resolution of the defect measurement needs to be 0.5 μm or less.

In addition, since the effect on the device differs depending on the size of the defect, the size must be evaluated. Irradiating light of one wavelength absorbed by the wafer as in the conventional face plate defect inspection apparatus shown in the third known example,
When detecting scattered light from a defect, there is a disadvantage that neither the size nor the depth can be obtained because the scattered light intensity varies depending on the depth position of the defect and the defect size.

According to the method shown in the fourth known example, 532 nm is selected as the wavelength of the first irradiation light having a short penetration depth, and light having a wavelength from the wafer surface to a depth of about 0.5 μm is formed at a depth of a crystal defect. And the defect size can be calculated from the scattered light intensities of the two wavelengths. This technology makes it possible to measure crystal defects on the entire surface of the wafer, which was not possible until now, and to gain knowledge on the depth and size of crystal defects on the entire surface of the wafer.
It is now possible to evaluate defects, hydrogen annealing, ion implantation, and other defects induced by device processes, polishing defects on the wafer surface, and the in-plane position, depth, and defect size of attached foreign matter in the wafer. Was. However, in this method, the detected various scatterers are superimposed and displayed in the in-plane distribution, and for example, the evaluation of the depth and the defect size of only the internal defects except for the influence of surface polishing flaws and foreign matter is performed. I can't do that. Similarly, it is not possible to evaluate the depth or defect size of the scatterer group existing only in a specific region in the in-plane distribution.

Further, when a new characteristic distribution is found in the depth and size of a defect, that is, when a new group of crystal defects having a new feature is found, it is not possible to evaluate what in-plane distribution they have. .

SUMMARY OF THE INVENTION The present invention has been made to overcome the above-mentioned problems, and provides a crystal defect measuring method and apparatus which can easily separate and display a defect at a position or a type unit and therefore can easily evaluate a defect. It is intended to do so.

[0025]

According to one aspect of the present invention, a crystal sample is irradiated with irradiation light, and one of the sample and the irradiation light is scanned with respect to the other to individually scatter the sample. In the crystal defect measuring method for measuring a crystal defect of the sample by detecting scattered light from a body, the intensity of the scattered light larger than a predetermined value and the generation position thereof are stored among the scattered light intensities. Displaying one of a planar distribution of the scatterer that gives the stored scattered light intensity and a graph based on the stored scattered light intensity, with the axis related to the value related to the scattered light intensity of the irradiation light. And selecting one specific area from the one display, corresponding to the selected area or an area other than the selected area,
Identifying and displaying the other area of the planar distribution and the graph.

According to another aspect of the present invention, there is provided an irradiation system for irradiating a crystal sample with irradiation light, and one of the sample and the irradiation light is scanned with respect to the other to separate each sample from the individual scatterers of the sample. Means for detecting the scattered light of the sample, thereby measuring a crystal defect of the sample, the intensity of the scattered light greater than a predetermined value among the scattered light intensity and the generation position thereof And a graph based on the stored scattered light intensity, with the plane distribution of the scatterer giving the stored scattered light intensity and a value related to the scattered light intensity of the irradiation light as an axis. Means for selecting one specific area from the display of one of the planar distribution and the graph, and corresponding to the selected area or an area other than the selected area, of the planar distribution and the graph Characterized in that so as to display to identify the other region.

[0027]

FIG. 1 shows an embodiment of an irradiation and detection optical system of a crystal defect measuring apparatus according to the present invention. First
In the irradiation system 4, the second harmonic light of the YAG laser having a wavelength of 532 nm as the first irradiation light 1 is adjusted to p-polarized light with respect to the surface of the sample (silicon wafer) 11 by a polarizer. The polarized light is turned back by the first turning mirror 2, condensed by the first condenser lens 3, and irradiated on the silicon wafer from a direction in which the optical axis of the incident light becomes the Brewster angle of silicon (about 75 degrees). The irradiation in the p-polarized light direction at the Brewster angle focuses on the fact that the reflectance on the silicon surface is lower than that of the s-polarized light, and is intended to reduce the loss of irradiation light intensity to internal defects. This condition is not necessarily required, but it is desirable.

Similarly, in the second irradiation system 8, the second irradiation light 5 uses a semiconductor laser having a wavelength of 810 nm, is turned back by the second turning mirror 6, and is condensed by the second condensing lens 7.
The optical axis of the incident light is the Brewster angle of silicon (about 75
The silicon wafer is irradiated at a Brewster angle from the direction of (degree). Regarding the selection of the wavelength, two wavelengths whose penetration depths into the solid are different by at least three times are selected. 3 penetration depth
If the difference is more than twice, the attenuation of the long wavelength is about 50% in the depth range where the short wavelength can penetrate, and the error in calculating the particle size of the scatterer from the scattered light signal of the long wavelength by Rayleigh scattering theory is 10%. It is estimated that it is within.

The light irradiated by the first and second irradiation systems 4 and 8 is scattered by internal defects. Forward scatter of the scattered light does not return to the outside of the wafer again.
Of the backscattered light, scattered light having an angle larger than the critical angle (about 14.5 degrees) due to the interface between silicon and air is totally reflected within the silicon wafer and does not reach the outside of the wafer. Only scattered light smaller than the critical angle passes through the interface between the silicon wafer and air and reaches the outside of the wafer. The scattered light reaching the outside of the wafer is captured by the objective lens 9 and the scattered light 1
It goes to the detector as 0.

The entire scanning of the irradiation light on the silicon wafer is performed in a spiral manner by irradiating the silicon wafer whose rotation and center are being translated. Scanning is performed by controlling the angular velocity of rotation to be ω and the distance r from the center of rotation of the measurement position to be r, so that r × ω is always constant, that is, the linear velocity is constant. At the moment the scatterer passes through the irradiation area, pulse-like scattered light is generated. The scatterers include oxygen precipitates (SiO 2 particles) contained in the sample (silicon wafer) 11, crystal defects such as dislocations, and foreign substances attached to the wafer surface.

FIG. 2 shows the overall configuration of an embodiment of the crystal defect measuring apparatus according to the present invention.

The scattered light 10 from the defect in the sample 11 is condensed by using the objective lens 9, and the dichroic mirror 1
The light is branched at 2, and the lights of wavelengths 532 nm and 810 nm are separated, condensed by lenses 13 and 14, respectively, and detected by photodetectors 15 and 16 for each wavelength. The respective detection signals are amplified by amplifiers 17 and 18, respectively, and A / D
Digitized by the converters 19 and 20 and the computer 2
Take in 1.

Here, only when the scattered light intensity signal from the detector 532 having a wavelength of 532 nm exceeds a predetermined threshold value, the detector 15 having a wavelength of 532 nm and the wavelength 810 nm are provided.
The scattered light intensity value of the detector 16 is digitized and stored in the memory of the computer 21. The position where the scattered light is generated in the in-plane position of the silicon wafer is also recorded together with the scattered light intensity.

The detectors 15 and 16 may digitize the scattered light intensity and store the scattered light intensity in the memory of the computer 21 only when both of them detect a scattered light signal of a threshold value or more.

On the other hand, the driver 21 is transmitted from the computer 21.
The coordinates (R) of the rotary encoder and the translation encoder attached to the wafer fixing jig 26 while scanning the rotation stage 24 and the translation stage 25 in the rotation direction (θ direction) and the radial direction (R direction) using , Θ) is monitored, and the coordinates (R, θ) at the moment when the scattered light is generated from the defect are taken into the computer 21 together with the scattered light intensity signal.

In order to calculate the particle diameter of the scatterer within an error of 10%, two wavelengths whose penetration depths differ by more than three times are used. Here, the first irradiation light (532 nm) and the second irradiation light (810 nm) are used. ) Are S1 and S
Assuming that 2, the depth and the grain size of the defect can be obtained from Expressions 8 and 9.

Calibration of Depth of Defect (Equation (8) and (9)
Determination of the constant of the formula) can be performed by measuring a standard sample. That is, a wafer having a surface coated with polystyrene latex beads having a known particle diameter is suitable as a standard sample having a particle size, and an epitaxial wafer having a known thickness of an epitaxial layer is suitable as a standard sample having a depth. The reason why an epitaxial wafer with a known epitaxial layer thickness is used as a standard sample is that the defect density in the epitaxial layer is very small compared to the defect density in the substrate under the epitaxial layer, so it is used as a standard sample for defect depth distribution. What you can do.

With the configuration shown in FIG. 2, the irradiation wavelength of 532 nm exceeds the threshold value set in advance as described above.
Signal intensity of the pulsed scattered light of the above, irradiation wavelength 8 at this time
It is possible to store or record the scattered light intensity of 10 nm and the coordinates (r, θ) on the wafer where the pulse signal exceeding the threshold value is detected.

FIG. 3A shows the coordinate distribution (planar distribution) of the scatterer giving the pulse signal detected in this way.
This is an example in which a model is displayed on a display device 27 connected to the computer 21 in FIG. 2 by a plane distribution display function. The outer circumference circle indicates the measurement area or the outer circumference of the silicon wafer as the sample. The black circles in the figure represent scatterers from which signals exceeding the threshold were detected. Actually, one scatterer is represented by a dot or a symbol such as a square or a triangle which is higher than the resolution of the output of a screen or a printer. However, in order to help explain the following embodiment, black circles are used for the following two types. Not written in (1) In a portion where a plurality of straight lines are displayed as being dense, dots or squares, triangles, or other symbols having a resolution higher than the resolution of the above-mentioned screen or output from a printer are continuously distributed in a straight line. The objects are displayed and recognized as straight lines, but here they are indicated by straight lines for simplicity.
Also, (2) the shaded display shows a state where a very large number of scatterers are densely packed, and the resolution of the output of the above-mentioned screen or printer is originally intended. The above-mentioned dots or symbols such as squares and triangles should be densely distributed and displayed.

FIG. 3A shows a plurality of types (or features).
Since all the scatterers are displayed, it is difficult to intuitively analyze the defect.

FIG. 3B shows an example in which a graph corresponding to the planar distribution of the scatterers shown in FIG. 3A is displayed on the display device 27 shown in FIG. 2, and the horizontal axis is derived by equation (9). Particle size,
The vertical axis represents the depth derived by equation (8). This device irradiates two wavelengths and detects each scattered light.
The two-dimensional difference due to the characteristics of the scatterers that could not be separated by the method of irradiating the wavelength and detecting the scattered light is shown in FIG.
In this case, there is a high possibility that separation can be performed in terms of particle size versus depth.

The operator looks at FIG.
Eight defect groups are selected on the graph. Mouse,
Instructions are given in the figure by a computer input device such as a trackball, joystick, keyboard and the like. As a method of selecting an area by the input device, an arbitrary polygon can be selected in the graph. Alternatively, the area selection method may be such that a diagonal line of a rectangle can be specified in the graph, or an elliptical area can be specified. Then, a plurality of areas can be selected. After selecting a region, a selection is made as to whether only the selected region is to be reflected in the planar distribution or a portion excluding the selected region is to be reflected in the planar distribution. The selection whether to reflect only the selected portion on the planar distribution or reflect the portion excluding the selected region on the planar distribution may be performed before selecting the region.

Regarding the plane distribution and graph of the scatterer,
One of them may be deleted and the other may be displayed (update display), or both may be displayed independently (independent display).

FIGS. 4 (a) and 4 (b) show a plane distribution and a graph of the scatterer in a selected specific area in FIG. The region 28 in FIG. 4B is a group of scatterers distributed over a wide particle size range at the zero depth position, that is, near the surface.
Those having such a distribution have a high possibility of a wafer polishing defect or the like that affects the yield of device formation. FIG. 4A selectively displays a group of scatterers distributed over a wide particle size near the wafer surface, and clarifies the spatial distribution.

Although only the selected specific area is displayed, it is possible to select a further area even in a figure in which an area has already been selected or excluded.

FIGS. 5A and 5B show the planar distribution and graphs of the scatterers in the region excluding the selected region 28 in FIG. That is, a plane distribution and a graph of the scatterer in a region excluding the region in FIG. 4 are shown.

After confirming the plane distribution of FIG. 5A, a graph of this plane distribution display is displayed again to obtain FIG. 5B. FIG. 6 shows the planar distribution of the scatterers in the region excluding the regions 31 and 32 in the same procedure from FIG. 5B. The region 31 is haze caused by micro-roughness on the wafer surface, and the region 32 has a high possibility of extremely minute polishing flaws. Region 29 and region 3 in FIG.
FIG. 7 and FIG. 8 show 0 in a plane distribution. It has been found that a group of scatterers that appear with a specific particle size near the surface, such as in the region 29, may be a COP on the wafer surface. In addition, a group of scatterers that appear with a specific particle size inside the wafer as in the region 30 is highly likely to be a grown-in defect generated when the wafer is lifted. FIG.
It is extremely difficult to analogize FIG. 8 with FIG. 8 from FIG. 6, and it can be said that the present invention has made it possible to separate the scatterers due to differences in their features. Being able to separate on a planar distribution by its features is useful for managing crystal defects and yield in device formation. This is because the planar distribution of a specific type of defect as a result of the separation serves as a guideline for determining whether or not the yield is affected.

Further, an area within the plane distribution is selected, and a graph display of only the selected area or a graph display of an area excluding the selected area becomes possible. In the same manner as above, a polygon, rectangle, or ellipse is selected by an input device such as a mouse.
Is performed with a shape having a limited range. For example, the scatterer group 32 'shown in FIG. 3A is selected by a polygon (FIG. 9).
(A)). If the feature of this defect group is not well understood, only the selected area is displayed as a graph. In this case, FIG. 9B is obtained. FIG. 9 (a) may have minute polishing flaws, but it can be seen that the scatterers having such a planar distribution are distributed in the graph as shown in FIG. 9 (b). It greatly contributes to analysis.

Alternatively, if it is known that the region 28 'is a polishing flaw or a foreign matter adhering to the surface for some reason, and it is desired to evaluate the remaining scatterer group by a graph excluding the influence, the region 28' After selecting, the graph of the area excluding this is displayed as shown in FIG.
(B) is obtained, which greatly contributes to further analysis of crystal defects of the wafer.

Here, as an example of the graph, a graph centering on the particle diameter and the depth as shown in FIG. 3B is shown. Alternatively, another amount obtained by calculation from the scattered light intensity from two wavelengths may be selected as a graph. As an example of the axis to select,
Scattered light intensity from irradiation light 532 nm or 810 nm,
These logarithms and the amount obtained by dividing the scattered light intensity by 1/6 (the amount proportional to the particle size) are given. In addition, a frequency distribution graph of the amount selectable as the axis (including the particle diameter and the depth) at each wavelength may be created, and the range of the amount selectable as the axis may be selected from this.

The flow of the above operation will be described with reference to the flowchart of FIG.

In a state 33 where the in-plane distribution or the graph is displayed on the screen, it is determined whether or not an area is to be selected. When selecting an area, the area is actually selected 35. After the selection, the user selects 36 whether to display data in the selected area or to display an area looking through the selected area. When selecting an area, the computer of the apparatus selects 37 the data in the area, and when displaying a portion excluding the selected area, the computer selects 38 the data of the excluded part. After the computer selects the data, the display is updated 39. Subsequently, if the plane distribution is currently displayed, the graph is selected, and if the graph is displayed, whether to switch the display to the plane distribution is selected 40. When the display is switched, the display is switched and updated 41. If not selected, the process ends 42.

When it is determined whether or not to select a region, even if the region is not selected, the graph is displayed on the graph if the planar distribution is currently displayed. If so, it is possible to select 40 whether to switch the display to the planar distribution. The selection of whether to display the data in the selected area or to display the data excluding the selected area may be performed before selecting the area 35, and the options may be stored and the display may be updated 39. .

According to the embodiment of the present invention, in the silicon wafer crystal defect measuring apparatus, a graph representing the in-plane distribution of the scatterer or an arbitrary region on the graph representing the property of the scatterer is selected to represent the property of the scatterer. Alternatively, by displaying the distribution in the plane, it is easy to separate and display the positions and types of the scatterers, and therefore, it is easy to qualitatively evaluate and manage the wafer.

[0055]

According to the present invention, there is provided a crystal defect measuring method and apparatus which can easily display a defect in units of positions or types of defects, and thus can easily evaluate defects.

[Brief description of the drawings]

FIG. 1 is an irradiation and detection optical system diagram of a crystal defect measurement apparatus showing one embodiment according to the present invention.

FIG. 2 is an overall configuration diagram of an embodiment of a crystal defect measurement device according to the present invention.

FIG. 3 is a plane distribution and a graph of a scatterer.

FIG. 4 is a diagram showing a planar distribution and a graph of a scatterer in a selected specific region in FIG. 3;

FIG. 5 is a diagram showing a planar distribution and a graph of scatterers in an area other than a selected specific area in FIG. 4;

FIG. 6 is a diagram showing a planar distribution of scatterers in a region other than the selected specific region in FIG. 5;

FIG. 7 is a diagram showing a planar distribution of scatterers in a selected specific area in FIG. 5;

FIG. 8 is a diagram showing a planar distribution of scatterers in another selected specific region in FIG. 5;

FIG. 9 is a diagram showing a planar distribution and a graph of a scatterer in another selected specific area in FIG. 3;

FIG. 10 is a flowchart showing an example of a flow of an operation based on the present invention.

[Explanation of symbols]

1: first irradiation light, 2: first turning mirror, 3: first condenser lens, 4: first irradiation system, 5: second irradiation light, 6: second
Folding mirror, 7: second condenser lens, 8: second irradiation system, 9: objective lens, 10: scattered light, 11: sample (silicon wafer), 12: dichroic mirror, 13: lens 1, 14: lens 2 , 15: Photodetector 1, 16: Photodetector 2, 17: Amplifier 1, 18: Amplifier 2, 19: A
A / D converters 1, 20: A / D converters 2, 21:
Computer, 22: rotary stage driver, 23: translation stage driver, 24: rotary stage, 25: translation stage, 26: wafer fixing jig, 27: display device, 2
8-32: defect group.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Jin Komuro 882 Momo, Oaza-shi, Hitachinaka-shi, Ibaraki F-term in Measuring Instruments Division, Hitachi, Ltd. 2G051 AA51 AB01 AB02 AB06 AB07 AC21 BA01 BA06 BA08 CB05 CD05 DA06 DA08 EA11 EA12 EA14 FA02

Claims (8)

[Claims] A crystal sample is irradiated with irradiation light, and one of the sample and the irradiation light is scanned with respect to the other to detect scattered light from individual scatterers of the sample, thereby obtaining a crystal defect of the sample. In the crystal defect measurement method of measuring the scattered light intensity, of the scattered light intensity, storing the intensity of the scattered light greater than a predetermined value and its generation position, the plane of the scatterer giving the stored scattered light intensity Displaying one of a distribution and a value based on the scattered light intensity of the irradiation light as an axis, and a graph based on the stored scattered light intensity, and displaying one specific region from the one display. To choose,
A crystal defect measurement method including a step of specifying and displaying the other area of the planar distribution and the graph corresponding to the selected area or an area other than the selected area. 2. The crystal according to claim 1, wherein the graph has one axis as an amount related to the size of the scatterer and the other axis as an amount related to the depth of the sample. Defect measurement method. 3. The crystal defect measuring method according to claim 1, wherein the graph is a graph centering on the frequency of an amount related to the scattered light intensity of the irradiation light. 4. The apparatus according to claim 1, wherein the irradiation light is obliquely incident on the sample, and the irradiation light includes first and second wavelengths different from each other.
One of the second wavelength light and the second wavelength light has a penetration depth of three times or more into the sample as compared with the other wavelength light. 5. An irradiation system for irradiating a crystal sample with irradiation light, and means for scanning one of the sample and the irradiation light with respect to the other to detect scattered light from individual scatterers of the sample. In the crystal defect measuring apparatus for measuring crystal defects of the sample thereby, among the scattered light intensities, means for storing a scattered light intensity larger than a predetermined value and a generation position thereof, and the stored memory. Means for displaying a graph based on the stored scattered light intensity, with a plane distribution of the scatterer providing the scattered light intensity and a value related to the scattered light intensity of the irradiation light as an axis, the plane distribution and Select a specific area of one of the graphs from the display,
A crystal defect measuring apparatus, wherein the other area of the planar distribution and the graph corresponding to the selected area or an area other than the selected area is specified and displayed. 6. The crystal according to claim 5, wherein the axis of the graph is an amount related to the size of the scatterer, and the other axis is an amount related to the depth of the sample. Defect measurement device. 7. The crystal defect measuring apparatus according to claim 5, wherein the graph is a graph centered on the frequency of an amount related to the scattered light intensity of the irradiation light. 8. The irradiation system according to claim 5, wherein the irradiation system is configured to make the irradiation light obliquely incident on the sample, and the irradiation light is different from the first and second irradiation lights.
And a depth of penetration of the first and second wavelengths of light into the sample is three times or more that of the other of the first and second wavelengths of light.