JPH0731129B2 - Semiconductor wafer particle detector - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a semiconductor LSI wafer, and more particularly to a foreign matter detection apparatus suitable for detecting minute foreign matter on a patterned wafer in an LSI manufacturing intermediate step with high speed and high sensitivity. .

[Background of the Invention]

In a conventional foreign matter inspection apparatus on a wafer, (i) a combination of one-dimensional high-speed scanning of laser light and translation low-speed movement of a sample, or (ii)
The entire surface of the sample was scanned and detected by using a linear scan which is a combination of high-speed rotation of the sample and translational low-speed movement.
Further, in JP-A-57-80546 (known example 1), a scanning equivalent to the above (i) is realized by combining the electrical scanning of the self-scanning type one-dimensional photoelectric conversion element array and the low speed movement of the sample. In addition, Automatic Microcircuit and Wafer Inspection, El
In ectronics Test, Vol.4, No5, May 1981, PP.60-70 (known example 2), a self-scanning type one-dimensional photoelectric conversion element array is arranged at the radial position of the sample wafer, and this is combined with the rotational movement of the sample. As a result, scanning equivalent to that in (ii) above is realized.

However, according to the methods of the publicly known examples 1 and 2, it is inevitable to "miss" the foreign matter when the dead zone existing in the adjacent portion of each photoelectric conversion element picture element scans the foreign matter. In order to strictly avoid this, it is necessary to install a plurality of photoelectric element arrays so as to overlap the dead zone. This causes an increase in the number of signal processing circuits and a decrease in reliability. However, even if the photoelectric element arrays do not overlap, if the size of the foreign matter to be detected is sufficiently larger than the insensitive body width, or if the total dead band width is negligible compared to the total photoelectric conversion element pixel width. If it is small, the "missing" is not a big problem. In the methods of the known examples 1 and 2, the "missing" due to the dead zone is ignored from such a viewpoint.

[Detection of foreign matter on patterned wafer]

The foreign material inspection work on patterned wafers in the intermediate process of LSI manufacturing is indispensable for improving product yield and reliability. Automation of this work is disclosed in JP-A-55-149829 and JP-A-54-1.
This is realized by a detection method using polarized light as shown in a series of patents such as 01390, JP-A-55-94145 and JP-A-56-30630. This principle will be described with reference to FIGS. 19 to 26.

As shown in FIG. 19, if the illumination light 4 is only projected onto the surface of the wafer 1 at an inclination angle φ, the reflected light and the scattered light 5, 6 are simultaneously generated from the pattern 2 and the foreign matter 3, so that the pattern 2
Therefore, it is not possible to distinguish and detect only the foreign matter 3. Therefore, a device for detecting the foreign matter 3 by using polarized laser light as the illumination light 4 was made.

As shown in FIG. 20 (a), the pattern 2 existing on the wafer 1 is irradiated with the S-polarized laser light 4. (Here, the case where the electric vector 10 of the laser beam 4 is parallel to the wafer surface is referred to as S-polarized laser illumination.) Generally, the surface irregularities of the pattern 2 are sufficiently smaller than the wavelength of the illumination light when viewed microscopically. Since it is smooth, the reflected light 5 also holds the S-polarized component 11. Therefore, if the analyzer 13 which shields S-polarized light is installed in the optical path of the reflected light 5, the reflected light 5 is shielded and the photoelectric conversion element 7
Does not reach. On the other hand, as shown in FIG. 20 (b), in addition to the S-polarized component 11, the P-polarized component is included in the scattered light 6 from the foreign matter 3.
12 is also included. This is because the P-polarized light component 12 is generated as a result of the roughening of the surface of the foreign substance 3 and the elimination of polarization. Therefore, the P-polarized component 14 passing through the analyzer 13 is transferred to the photoelectric conversion element 7
The foreign substance 3 can be detected by the detection.

Here, the pattern reflected light is laser light 4 as shown in FIG.
On the other hand, when the angle formed with the longitudinal direction of the pattern 2 is right, the reflected light 5 is completely blocked by the analyzer 13,
If this angle is different from the right angle, the light is not completely shielded.
This consideration is Vol.17, No2, P.232 of the Society of Instrument and Control Engineers.
~ P242, 1981. According to this, since only the reflected light from the pattern whose angle is within ± 30 ° from the right angle is incident on the objective lens installed above the wafer,
The pattern reflected light 5 in this range is not completely shielded by the analyzer 13, but its intensity is small enough to be discriminated from the foreign substance scattered light of 2 to 3 μm, so that there is no practical problem.

Here, the tilt angle φ of the polarized laser light 4 is set to about 1 ° to 3 °. This is for the following reason. In the experiment shown in FIG. 21, the intensity V _S of the analyzer 13 passing component 14 and the analyzer passing component intensity V _P of the pattern reflected light 5 of the 2 μmφ foreign substance scattered light with respect to the S-polarized laser 4 were set to the objective lens 9 (magnification 40X, N .
A = 0.55) was used for the measurement. The experimental results are shown in FIG. The horizontal axis represents the laser tilt angle φ, and the discrimination ratio V _S / V _P of the foreign matter / pattern was plotted. From the figure, V _S can be easily discriminated from V _P when the inclination angle φ is 5 ° or less.
Stable foreign object detection is possible. In consideration of design matters, φ = 1 ° to 3 ° is optimal. (JP-A-56-30
630) Here, two laser light sources 15 are used from the left and right,
This is for the purpose of enabling stable detection of a foreign substance that generates scattered light having anisotropy.

Next, a foreign matter inspection method using this detection principle will be described with reference to FIGS. 23 to 26.

As shown in FIG. 23 (a), a slit 8 is provided on the sample image forming surface to limit the detection range. As a result, only the scattered light within the range of the projected area 8a of the opening of the slit 8 on the sample is detected at a time. Therefore, the scattered light of foreign matter is larger than the integrated intensity 14p of the pattern reflected light P component within this area. If the P component 14d is sufficiently large, the foreign matter 3 can be detected stably. Therefore, if this area 8a is made to have the same size as the size of the foreign matter to be detected (2 to 3 μm), the detection sensitivity will be optimum, but the number of scans as shown in FIG. 23 (b) is large. And has a long inspection time. On the contrary, if the opening area 8a is increased, the inspection can be performed in a short time, but the detection sensitivity is deteriorated. Considering this, the area 8a is now set to 10 × 200 μm ² and 2
(For 150 cm ^phi wafer) foreign substances ~3μm about 2 minutes being inspected. This situation will be described with reference to FIGS. 24 and 25.

First, FIG. 24 shows a plan view (a) and a sectional view (b) of the wafer surface. The pattern 2 has (i) a slight depression of the pattern and (ii) a portion having an angle other than a right angle with respect to the irradiation direction of the laser beam 4, and each of these portions (the depression and the corner portion of the edge of the pattern 2) Since scattered light (mainly S-polarized light component) containing a small amount of P-polarized light component (other than S-polarized light component) is generated, the P-polarized light component passes through the S-polarized light shielded analyzer 13, and FIG. The scattered light of the P-polarized component (other than the S-polarized component) as shown in (a) is detected and received by the aperture 8a, whereby the signal 14p shown in FIG. 25 (b) is obtained. On the other hand, from a large foreign substance 3b of 2 μm or more, FIG. 25 (b)
As shown in FIG. 7, the signal 14d having the P-polarized component having a larger intensity than that of each of the points (i) and (ii) is detected. However, from the minute foreign matter 3a having a size of about 0.5 to 2 μm, as shown in FIG. 25 (b), the above (i), (ii)
Signal having the same degree of P-polarized component as each of the
14d is detected. Therefore, there is a problem that the minute foreign matter 3a having a size of about 0.5 to 2 μm cannot be discriminated from the dents and the corners of the edge of the pattern 2.

FIG. 25 shows the signal output of the photoelectric conversion element 7 when the aperture 8a scans the sample. In the figure (a), P component 14p
The distributions of (circuit pattern) and 14d (foreign matter) on the sample are shown. When the aperture 8a scans over this distribution, the output shown in FIG. In this example, the outputs from the small foreign matter 3a and the edge of the pattern 2 are the same, so the threshold value indicated by the broken line must be set to a position higher than this output.
Limited to detecting only large foreign matter.

However, in manufacturing a highly integrated LSI typified by a 256 Kbit memory-LSI, the presence of foreign matter having a size of 1 μm has a great influence on the product yield, so that the detection sensitivity of the foreign matter of 1 μm is required. This is the device shown in FIG.
If it is limited to m ² or less, the cumulative effect of the scattered light P component of (i) and (ii) is reduced as compared with the case where the opening 8a is 10 × 200 μm ² , and as a result, 1 μm foreign matter is detected. It will be possible. However, in this case, the inspection time becomes about 40 times, which is not synchronized with the manufacturing throughput, and there is a problem in practical use.

[Object of the Invention]

An object of the present invention is to solve the above-mentioned problems of the prior art with high sensitivity to minute foreign particles of 2 μm or less existing on a semiconductor wafer having a circuit pattern, regardless of the orientation of the circuit pattern. It is an object of the present invention to provide a semiconductor wafer foreign matter detection device capable of discriminating and detecting at high speed without overlooking.

[Outline of Invention]

That is, to achieve the above object, the present invention provides an illumination optical means for illuminating linearly polarized laser light on a semiconductor wafer having a circuit pattern formed thereon at an inclination angle of 5 ° or less with respect to the wafer surface. Provided, the scattered light reflected from the semiconductor wafer by the linearly polarized laser light illuminated by the illumination optical means and generated in a direction substantially perpendicular to the surface of the semiconductor wafer is condensed to form an enlarged image on the light receiving portion. And a light-shielding optical system that shields the linearly polarized scattered light generated from the edge of the circuit pattern among the scattered light that is magnified and image-formed by the light-collecting optical system. Avoid the overlooking of minute foreign matter by arranging each light receiving part that receives the scattered light other than the linearly polarized light obtained through the light blocking optical system that is enlarged and image-formed by the optical optical system in a rectangular shape and is continuously arranged. As adjacent to Solid-state image sensor capable of performing high-speed scanning by providing a dead zone between the light-receiving portions so that the light-receiving portions of each shape are overlapped with each other at least in a direction perpendicular to the scanning direction and the light-receiving portions output in parallel. An array, the relationship between the size of each light receiving portion of the semiconductor solid-state imaging device array and the magnifying image-forming magnification of the condensing optical system is calculated based on the scattered light other than the linearly polarized light obtained through the light shielding optical system. Each of the light-receiving portions has a size of about 10 μm on the semiconductor wafer so that the amount of scattered light generated by a minute foreign substance having a size of 2 μm or less on the semiconductor wafer is larger than the amount of scattered light generated by the edge of the circuit pattern received by each light-receiving portion. 10 μm
Providing a detection optical means set to receive the following rectangular shaped portion, the scanning means for scanning the semiconductor wafer in the scanning direction intersecting with the arrangement direction of the light receiving portion of the semiconductor solid-state imaging device array, The reflected light image from the surface of the semiconductor wafer is received by the photoelectric conversion means through the condensing optical system, and the semiconductor wafer is finely moved in the vertical direction based on the signal obtained from the photoelectric conversion means to illuminate the surface of the semiconductor wafer. Focusing control means for controlling the focusing means to the optical means and the detection optical means is provided, and the semiconductor wafer controlled to the focusing state by the focusing means is scanned by the scanning means to form a semiconductor solid-state imaging device array. A logical sum circuit for taking a logical sum of signals output from the respective light receiving units in parallel at the same time is provided, and based on the logical sum signal obtained from the logical sum circuit. A semiconductor wafer foreign substance detecting device characterized by being configured to detect the fine foreign matter with a 2μm or less in size on a semiconductor wafer having a road pattern.

Example of Invention

 An embodiment of the present invention will be described in detail with reference to FIGS.

FIG. 1 shows a state in which a solid-state image sensor array 20 is used instead of the slit 8 of the conventional example shown in FIG.

FIG. 2 illustrates an example of the solid-state image sensor array 20. Light receiving section
Reference numeral 20a denotes a silicon photodiode or a GaAsP photodiode, of which the PIN junction type is particularly suitable for the application of the present invention because it has characteristics of high-speed response and high sensitivity. Each light receiving portion (pixel) 20a is tilted with respect to the array direction of the solid-state imaging device array (and naturally the dead zone 20b is also tilted), and the width (length and width) of the light receiving portion (pixel) 20a is 5
00μm, width 50μ between adjacent pixels (light receiving part)
There is a dead zone 20b of m. When the solid-state imaging device array 20 has 40 pixels (the number of light receiving parts), for example, the total magnification of the detection system is 100 times (the magnification of the objective lens 9 is 40X and the relay lens (not shown)). If the magnification is 2.5X), the size of light received by one pixel (each light receiving part) is 5 μm × 5 μm (however, it is tilted) on the surface of the sample (wafer 1), and eventually solid-state imaging Element array 20
Means that scanning is performed while detecting a range of 5 μm × 220 μm on the sample surface, and the inspection speed is approximately the same as the conventional one.

The effect of this solid-state image sensor array 20 will be described with reference to FIG.
For comparison, the case of the solid-state imaging device array 20 is shown in FIGS. 8A, 8B, and 8C, and the solid-state image pickup device array 20 is shown in FIGS.
The case of the conventional example shown in FIG. 23 is shown. The figure (a) shows the state where the solid-state imaging device array 20 scans and detects on the wafer, and the figure (b) shows each pixel (i, j, h, l, m) of the solid-state imaging device array 20. The video signals i ₁ , j ₁ , h ₁ , l ₁ , m _{1 obtained from the above} are shown. In FIG. 7C, each video signal i ₁ , j ₁ , h ₁ , l ₁ , m _{1 is set} to a threshold value V _TH. Binarized signal i ₂ , j ₂ , h ₂ , l ₂ , m ₂
FIG. Further, FIG. 6D shows a state in which the slit 8 scans the wafer and the photoelectric conversion element 7 detects the slit.
FIG. 7E shows the video signal V obtained from the photoelectric conversion element 7, and FIG. _6F shows the binarized signal binarized by the threshold value of the video signal V _TH ′. In addition, FIG.
In order to simplify the description, the number of pixels is 5 in (b) and (c).
K (i, j, h, l, m). That is, as described above, the size of each light receiving portion (pixel) is set to 5 μm × 5 μm on the sample surface according to the total magnifying imaging magnification of the detection system, and each light receiving portion (pixel) forms an S-polarized light-shielding analyzer 13. Since the scattered light other than the transmitted S-polarized component is received, the amount of scattered light other than the S-polarized component generated from the edge of the pattern 2 is 0.
The amount of scattered light other than the S-polarized component generated from the minute foreign substance 3a having a size of about 5 to 2 μm becomes large, and if the output signal h ₁ of the pixel h is binarized by the threshold value V _TH as shown in FIG. The converted signal h ₂ becomes “1” even for the small foreign matter 3 a, and the sensitivity can be improved as compared with the conventional case.

FIG. 4 shows a signal processing method of each pixel of the solid-state imaging device array 20. The output of each of the pixels i to n is a binarization circuit.
It is simultaneously binarized in parallel at 21 and the binarized signal (“1”) is
When the foreign matter is guided to the OR circuit 22 and the foreign matter is detected in at least one picture, the output of the OR circuit becomes “1”, and the foreign matter memory 23
To enter. By this method, 40 pixel outputs are processed in parallel at the same time, and the inspection speed and detection sensitivity can be greatly improved as compared with the case of using a self-scanning image sensor.

However, the dead zone 20b of the solid-state image sensor array 20 causes the drawbacks described below. This solution is shown in FIG.
It is shown in FIG. That is, as shown in FIGS. 5 and 7, when the array direction of the solid-state imaging device array 20 and the scanning direction are at right angles, the relationship between the dead zone 20b between the pixels i and j and the small foreign matter 3c is as shown in FIG. In such a case, the small foreign matter 3c is missed.

Therefore, as shown in FIGS. 6 and 8, if the dead band 20b is arranged with a large inclination so as to overlap the pixels 20a of the solid-state imaging device array 20 in the array direction, the above-mentioned overlooking can be avoided. I can. It should be noted that this amount of inclination needs to be equal to or larger than the size of the small foreign matter to be detected.

In FIGS. 6 and 8, the small foreign matter 3c may be detected by the pixels j and h in an overlapping manner, so that the result is double counted. However, as a method of avoiding this double counting, there are JP-A-56-132549, JP-A-56-118187 and JP-A-57-
The methods described in 66345, JP-A-56-126747 and JP-A-56-118647 may be used.

FIG. 9 shows an application example of the present invention in the case of streak scanning.

FIG. 10 shows the overall structure of the embodiment. The wafer 1 is moved in the XY directions by the X stage 46 and the Y stage 49 while being attracted to the wafer chuck 40 by the vacuum tube 41. The foreign substance information detected by the solid-state imaging device array 20 is binarized circuit 21,
The control circuit 32 including the foreign substance memory 23 is reached via the OR circuit 22 and displayed on the display device 33.

In the present invention, since the size of the pixel is set to about 5 × 5 μm ² (however, it is inclined) or less, if a defocus occurs due to the waviness of the wafer surface during the inspection, the foreign matter detection sensitivity is significantly lowered. . Therefore, by the automatic focus detection unit 30,
It is essential to use a configuration in which the defocus amount is detected during inspection and is fed back to the driver 31 of the focus mechanism motor 43. The principle of this autofocus function was announced in Fig. 22 SICE Academic Lecture Preprints, P223-P224, and JP-A-58-
As described in 70540, this principle will be described with reference to FIGS. 11 to 13. This method is suitable for the present invention because it is characterized by stable autofocusing without being affected by the pattern on the sample.

FIG. 11 shows the main part of the automatic focus detection unit 30. Stripe patterns 60a and 60b on the glass plate are objective lenses 9 respectively.
The image is projected onto the sample by, but the respective in-focus positions are set slightly too high and too low with respect to the in-focus point of the image sensor array 20. The image of each striped pattern 60a, 60b on the sample is magnified by the objective lens 9 and the semi-transmissive mirror 3
The light is reflected by 4, 62 and imaged on the image pickup device 61.

FIG. 12 (a) shows the projected fringe pattern imaged on the image pickup device 61 in the case of too much wafer down (Z <0), and FIG. 12 (d) shows the case in the case shown in FIG. 12 (a). 3 shows a video signal waveform detected by the image sensor 61. FIG. 12 (b) shows a projection pattern imaged on the image pickup device 61 in the case of the in-focus position (Z = 0), and FIG. 12 (e) shows an image pickup in the case shown in FIG. 12 (b). 3 shows a video signal waveform detected by the element 61. FIG. 12 (e) shows a case where the wafer is overly loaded (Z> 0),
The projected fringe pattern formed on the image sensor 61 is shown.
FIG. (F) shows the image sensor 61 in the case shown in FIG. 12 (c).
The video signal waveform detected by is shown.

Therefore, when the image pickup device array 20 is in focus, the detection signals of the image pickup device 61 are equal at the portions corresponding to the striped patterns 60a and 60b, so that the difference signal between the two is zero.

On the other hand, if it rises too much (or falls too much), the deviation from the in-focus point of the image sensor 20 corresponds to the magnitude of the output of the difference signal, so that the servo signal shown in FIG. 13 is obtained. The figure shows an example of actual measurement of the difference signal when the sample surface is an aluminum surface and when it is a complicated pattern (memory cell surface). This gives ±
Since focusing can be performed within 0.5 μm, stable foreign matter detection can be performed when the objective lens 9 has a magnification of 40 ×. As an autofocus mechanism, for example, as shown in FIG.
The configuration using the motor 43, the slope 45, the ball 44, and the leaf spring 42 is simple.

Next, another embodiment of the present invention will be described. That is, as shown in FIG. 14, even if the light receiving portion 200a is formed in a trapezoidal shape and the dead zone 200b is inclined, the light receiving portion 201a is also formed as shown in FIG.
Even if they are arranged in a staggered manner so as to overlap in the arrangement direction, the same operational effect as in the above embodiment can be achieved.

In this way, the solid-state image sensor array is shown in Figs.
As shown in Fig. 18, the bonding pads 20e, 200e, 201e and the wirings 20d, 200d, 201d are indispensable for connecting to external pins, and the light receiving parts (pixels) 20a, 200a, 201a are wider than the light receiving range. There is a need to.

Therefore, in order to increase the detection resolution, the optical shading parts 20c, 200c, 2
Paste 01c by printing, etc., and bond pad 20
It is important to block light at e, 200e, 201e and areas outside the light receiving range.

Further, the present invention is not limited to wafers and can be applied to inspection of other products such as photomasks and reticles.

Further, as shown in FIG. 27, the size (x × y) of each light receiving portion (pixel) of the solid-state imaging device array 20 and the detection system (objective lens 9
And a relay lens (not shown). ) With the total magnification imaging magnification m of (x ×) on the surface of the wafer 1.
y) / m is about 10μm × 10μm, 1.5μm to 2μm
It has been confirmed by experiments that there is no practical problem in detecting a minute foreign substance of m. That is, (x × y) / m should be about 10 μm × 10 μm or less on the surface of the wafer 1.
If the value of is set, 2 μm received by each light receiving unit (pixel)
The amount of scattered light other than the S-polarized component generated from the following minute foreign matter is made larger than the amount of scattered light other than the S-polarized component generated from the edge of the pattern 2, and the minute foreign matter of 2 μm or less can be detected with high sensitivity.

〔The invention's effect〕

As described above, according to the present invention, an illuminating means for illuminating the linearly polarized laser light with an inclination angle of 5 ° or less with respect to the surface of the semiconductor wafer, and the above-mentioned semiconductor by the linearly polarized laser light illuminated by the illuminating means. A condensing optical system that condenses and forms an image of scattered light that is reflected from the wafer and that occurs in a direction substantially perpendicular to the surface of the semiconductor wafer, and the scattered light that is condensed by the condensing optical system. A light-shielding optical system that shields the linearly polarized scattered light generated from the edge of the circuit pattern, and a semiconductor with respect to the scattered light amount generated from the edge of the circuit pattern among the scattered light other than the linearly polarized light obtained through the light-shielding optical system. The size of the light-receiving portion that magnifies and forms an image so that the amount of scattered light generated from a minute foreign substance having a size of 2 μm or less on the wafer is large, is determined from the magnifying imaging magnification of the condensing optical system. Converted to form a rectangular shape with a size of about 10 μm × 10 μm or less, and arrange these light-receiving parts in a row, so that the space between adjacent square-shaped light-receiving parts is at least perpendicular to the scanning direction to avoid overlooking small foreign particles. A dead zone is provided between the light-receiving portions so that they overlap with each other, and further, the semiconductor solid-state imaging device array capable of outputting in parallel from each light-receiving portion to enable high-speed scanning, and the reflected light image from the surface of the semiconductor wafer are collected. The semiconductor wafer is moved up and down based on a signal received by the photoelectric conversion means through the optical optical system and obtained from the photoelectric conversion means to bring the surface of the semiconductor wafer into a focused state with respect to the illumination means and the focusing optical system. And a focusing control unit for controlling the size of each light receiving portion of the semiconductor solid-state image pickup device array on the semiconductor wafer, converted to about 10 μm × 10 μm.
By providing the focusing control means with the following rectangular shape, it is possible to significantly improve the scattered light intensity received by each light receiving unit of the scattered light generated from a minute foreign substance of 2 μm or less existing at an arbitrary position. In addition to being able to detect the minute foreign matter existing on the semiconductor wafer having the circuit pattern with high sensitivity to the edge of the circuit pattern regardless of the direction of the circuit pattern, and to miss the minute foreign matter of 2 μm or less. It has the effect that it can be detected at high speed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a foreign matter inspection apparatus in which a semiconductor solid-state imaging device array of the present invention is used, and FIG.
FIG. 3 is a perspective view showing details of the semiconductor solid-state imaging device array shown in FIG. 3, FIG. 3 is a diagram for explaining a comparison between the present invention and a conventional example, and FIG. 4 is an output signal of the semiconductor solid-state imaging device shown in FIG. FIG. 5 is a diagram showing a processing circuit, FIG. 5 is a diagram showing a positional relationship between a dead zone and a foreign substance, FIG. 6 is a diagram showing a positional relation between a pixel (light receiving portion) and a foreign substance in the present invention, and FIG. The figure which shows the relative scanning direction with respect to the wafer of the semiconductor solid-state image sensor in the figure, FIG. 8 is the figure which shows the relative scanning direction with the wafer of the semiconductor solid-state image sensor in FIG. 6, and FIG. 9 is a semiconductor solid-state image sensor. Showing relative spiral scanning with respect to the wafer of FIG. 10, FIG. 10 is a block diagram showing the embodiment shown in FIG. 1 more specifically, and FIG. 11 is a perspective view showing the automatic focus detection unit shown in FIG. Fig. 12 is a diagram for explaining auto focus detection, Fig. 13 is obtained from the auto focus detection unit shown in Fig. 11. Diagram showing the relationship between the differential output and the defocus which, Figure 14 and Figure 15 each show a second drawing and other different semiconductor solid-state imaging device array FIG, FIG. 16 second
The figure specifically showing what is shown in FIG. 17, FIG. 17 is a figure more specifically showing what is shown in FIG. 14, and FIG. 18 is a figure showing more specifically what is shown in FIG. FIG. 19 is a cross-sectional view showing a wafer, FIG. 20 is a view showing a circuit pattern on a wafer with respect to an irradiated laser beam and a reflection state from a foreign matter, and FIG. 21 is a first example of a conventional foreign matter detecting method. Fig. 22 is a schematic perspective view, and Fig. 22 is the output ratio V _S / V _P when the tilt angle φ is changed in Fig. 21.
FIG. 23 is a schematic perspective view showing a second example of a conventional foreign matter detection method, FIG. 24 is a diagram showing a circuit pattern on a wafer and a reflection state from the foreign matter, and FIG. twenty three
FIG. 26 is a diagram showing the relationship of video signals obtained by scanning the slit relatively on the wafer, and FIG. 26 is a schematic perspective view showing a conventional foreign matter detecting method similarly to the second example shown in FIG. FIG. 27 and FIG. 27 show the size of each light receiving portion of the solid-state image pickup device array, the overall magnifying image forming magnification of the detection system, and the light receiving portion receiving light in the configuration showing the embodiment of the foreign matter inspection apparatus of the present invention shown in FIG. FIG. 6 is a perspective view for explaining the relationship with the size of pixels on the surface of the wafer. (Description of symbols) 1 ... Wafer, 2 ... Circuit pattern, 3 ... Foreign matter, 9 ... Objective lens, 13 ... Analyzer, 15 ... Polarized laser light source, 20 ... Photoelectric conversion solid-state image sensor array , 20a, 200a, 201a …… light receiving part, 20b, 200b, 201b …… dead zone.

Claims (3)

[Claims] 1. A semiconductor wafer having a circuit pattern formed thereon is provided with illumination optical means for illuminating linearly polarized laser light at an inclination angle of 5 ° or less with respect to the wafer surface, and is illuminated by the illumination optical means. An enlarged condensing optical system for condensing scattered light that is reflected from the semiconductor wafer by the linearly polarized laser light and occurs in a direction substantially perpendicular to the surface of the semiconductor wafer, and magnifies and forms an image on a light receiving portion; Of the scattered light that is magnified and imaged by the condensing optical system and condensed, the light blocking optical system that blocks the linearly polarized scattered light generated from the edge of the circuit pattern, and the magnified image by the condensing optical system The light receiving parts that receive the scattered light other than the linearly polarized light that is condensed and obtained through the light-shielding optical system are arranged in a square shape and are arranged consecutively, and adjacent square shape light receiving parts are provided so as to avoid overlooking minute foreign matter. At least A semiconductor solid-state image sensor array capable of performing high-speed scanning by providing a dead zone between the light-receiving portions so as to overlap with each other in a direction perpendicular to the scanning direction and outputting the light-receiving portions in parallel from each other, The relationship between the size of each light receiving portion of the image pickup device array and the magnifying image forming magnification of the above-mentioned condensing optical system is shown by the circuit pattern of each scattered light other than the linearly polarized light obtained through the above light shielding optical system. Each of the above-mentioned light receiving parts receives a square-shaped portion of about 10 μm × 10 μm or less on the semiconductor wafer so that the amount of scattered light generated from a minute foreign substance having a size of 2 μm or less on the semiconductor wafer is larger than the amount of scattered light generated from the edge. Scanning for scanning the semiconductor wafer in the scanning direction intersecting with the arrangement direction of the light receiving portions of the semiconductor solid-state imaging device array, by providing detection optical means set as necessary. A step is provided, and the reflected light image from the surface of the semiconductor wafer is received by the photoelectric conversion means through the condensing optical system, and the semiconductor wafer is finely moved in the vertical direction based on a signal obtained from the photoelectric conversion means. Focusing control means for controlling the surface to the focusing optical state with respect to the illumination optical means and the detection optical means is provided, and the semiconductor wafer controlled in the focusing state by the focusing point controlling means is scanned by the scanning means to form a semiconductor. On a semiconductor wafer having a circuit pattern which is provided with a logical sum circuit for taking a logical sum of signals output from the respective light receiving parts of the solid-state imaging device array in parallel and at the same time, and having a circuit pattern based on the logical sum signal obtained from the logical sum circuit. A semiconductor wafer foreign matter detection device, which is configured to detect a minute foreign matter having a size of 2 μm or less. 2. The semiconductor solid-state image sensor array as set forth above,
The light receiving section is arranged such that the dead zones between adjacent light receiving sections of a rectangular shape are inclined at least in a direction perpendicular to the scanning direction, and the light receiving sections are arranged so that the respective light receiving sections are overlapped with each other. Semiconductor wafer foreign matter detection device. 3. The semiconductor solid-state image sensor array as set forth above,
The light receiving units are arranged in a staggered manner so that the light receiving units overlap at least in a direction perpendicular to the scanning direction in a dead zone between adjacent square light receiving units. Item 6. The semiconductor wafer foreign matter detection device as described in the item.