JP5240980B2 - Three-dimensional measuring device and inspection device - Google Patents

Description

The present invention relates to a three-dimensional measuring apparatus that performs in-plane measurement of a sample surface and displacement measurement in the height direction.
Furthermore, the present invention relates to an inspection apparatus for inspecting a sample surface.

With increasing density of LSI, high planar accuracy is required for mask blanks and glass original plates used in the device manufacturing process. For example, if there are fine irregularities and undulations on the surface of the mask blank, the pattern is not accurately projected on the semiconductor wafer, which may adversely affect the manufacturing yield of the device. In the Levenson-type phase shift mask, a recess having a depth of about 100 nm is formed in the glass substrate as a phase shifter by etching, and the depth of the recess needs to be accurately measured. These fine recesses and steps and the displacement distribution in the height direction are measured by, for example, a Mach-Zender interferometer (see, for example, Patent Document 1).
JP 2000-241121 A

Since the interferometer detects a displacement in the height direction of the sample surface as a phase difference, it is possible to detect a minute displacement of about several nm on the sample surface. However, the interferometer has a problem in manufacturability because it is necessary to mount the optical elements constituting the optical system with high mounting accuracy, and its manufacturing tolerance is very small. In addition, since the price of the Nomarski prism or Mach-Zender interferometer is expensive, there is a drawback that the manufacturing cost of the measuring device or inspection device on which the interferometer is mounted is high.
Furthermore, since high throughput is required for surface inspection of semiconductor wafers and inspection of mask blanks, development of an inspection apparatus capable of three-dimensional measurement of a sample surface at high speed is strongly demanded.

An object of the present invention is to realize a three-dimensional measuring apparatus and an inspection apparatus that can inspect a sample surface at high speed.
Furthermore, another object of the present invention is to enable three-dimensional measurement of the sample surface with a resolution as high as that of the interferometer without using an interferometer, which can be manufactured at a relatively low cost and is easy to manufacture. Is to realize such a three-dimensional measuring apparatus.

A three-dimensional measuring apparatus according to the present invention has a light source that generates illumination light, and a light source device that has a slit in which an elongated opening is formed, and generates a linear illumination beam from the slit ;
An illumination optical system that projects a linear illumination beam emitted from the light source device obliquely to the sample surface;
An imaging optical system that collects a linear reflected beam emitted from the sample surface and forms an image of the slit on the imaging surface;
A light detection means disposed on the imaging surface of the imaging optical system and receiving a line-shaped reflected beam forming the slit image ;
A stage for supporting the sample and moving the sample in a direction perpendicular to the extending direction of the linear illumination beam;
Comprising a signal processing circuit for outputting a two-dimensional image information in the height direction of the displacement information and the sample surface of the sample surface based on the output signal from said light detecting means,
The light detection means includes a first line sensor and a second line sensor that are arranged in parallel to each other on the imaging plane and each have a plurality of light receiving elements arranged along the extending direction of the incident line-shaped reflected beam. Have
The light receiving element of the first line sensor and the light receiving element of the second line sensor are aligned with each other in a direction orthogonal to the arrangement direction thereof,
The signal processing circuit outputs means for outputting a difference signal between output signals of light receiving elements aligned with each other in a direction orthogonal to the arrangement direction of the light receiving elements of the first and second line sensors, and means for outputting an addition signal The displacement information in the height direction of the sample surface is output based on the difference signal, and the two-dimensional image information of the sample surface is output based on the addition signal.

  The present invention measures the displacement in the height direction of the sample surface based on the principle of so-called “optical lever”. When the sample surface is displaced in the height direction, the slit image formed by the linear illumination beam is displaced in one direction on the imaging surface of the imaging optical system in accordance with the amount of displacement of the sample surface. Therefore, in the present invention, two line sensors are arranged on the imaging surface of the imaging optical system. The light receiving elements of the two line sensors are arranged in a direction orthogonal to the displacement direction of the slit image. When the line sensor is arranged in this way, the amount of light incident on one light receiving element increases according to the displacement of the sample surface in the height direction, and the amount of light incident on the other light receiving element decreases. Therefore, by forming a differential signal between the output signals of the two corresponding light receiving elements, an output signal corresponding to the height direction displacement or the depth direction displacement of the sample surface can be obtained. Further, luminance information on the sample surface is output by forming an addition signal of the corresponding two light receiving elements. Furthermore, since the line sensor has a large number of light receiving elements (for example, 1024 light receiving elements) arranged in one direction, the displacement distribution in the height direction of the sample surface and Both two-dimensional image information is output.

  Therefore, only by scanning the sample surface once with the line-shaped illumination beam, the displacement distribution in the height direction of the sample surface and the two-dimensional image information are output, so that the sample surface can be inspected at high speed. Is possible. As a result, a three-dimensional measuring apparatus useful for an inspection apparatus that requires high throughput is realized.

  In a preferred embodiment of the three-dimensional measuring apparatus according to the present invention, the first and second line sensors are arranged so as to be directly adjacent to each other on the imaging surface of the imaging optical system. The elements are arranged so as to face each other across the boundary line of the line sensor.

  Another preferred embodiment of the three-dimensional measuring apparatus according to the present invention has stage position detecting means for detecting the position of the stage, and the position information of the light receiving element of the line sensor and the stage position information output from the stage position detecting means. Is output based on the address information, and a displacement distribution in the height direction of the sample surface is output based on the address information and the difference signal output.

  In another preferred embodiment of the three-dimensional measuring apparatus according to the present invention, a light source device, an illumination optical system, an imaging optical system, and a light detecting means are held on a support member, and a sample stage is placed on the sample on the support member. A drive mechanism that drives in a direction orthogonal to the support surface is connected, a focus error signal is formed from the difference signal, and the drive mechanism is operated based on the obtained focus error signal to perform focus control. To do.

An inspection apparatus according to the present invention is an inspection apparatus that optically inspects a sample surface,
A light source that generates illumination light, and a light source device that has a slit in which an elongated opening is formed, and that generates a linear illumination beam from the slit;
An illumination optical system that projects a linear illumination beam emitted from the light source device obliquely to the sample surface;
An imaging optical system that collects a linear reflected beam emitted from the sample surface and forms an image of the slit on the imaging surface;
A light detection means disposed on the imaging surface of the imaging optical system and receiving a line-shaped reflected beam forming the slit image;
A stage for supporting the sample and moving the sample in a direction perpendicular to the extending direction of the linear illumination beam;
Comprising a signal processing circuit for outputting a defect detection signal based on the output signal from said light detecting means,
The light detection means includes a first line sensor and a second line sensor that are arranged in parallel to each other on the imaging plane and each have a plurality of light receiving elements arranged along the extending direction of the incident line-shaped reflected beam. Have
The light receiving element of the first line sensor and the light receiving element of the second line sensor are aligned with each other in a direction orthogonal to the arrangement direction thereof,
The signal processing circuit outputs a difference signal between output signals of the light receiving elements aligned with each other in a direction orthogonal to the arrangement direction of the light receiving elements of the first and second line sensors, and the difference signal as a reference signal First comparison means for comparing, means for outputting an addition signal of output signals of light receiving elements aligned with each other in a direction orthogonal to the arrangement direction of the light receiving elements of the first and second line sensors, and the addition signal as a reference And a second comparison means for comparing with the signal, and performing defect determination based on the comparison result by the first comparison means and the comparison result by the second comparison means .

  Since the inspection apparatus according to the present invention has a high resolution of about several nanometers with respect to the displacement of the sample surface in the height direction, it is possible to inspect the surfaces of mask blanks and semiconductor wafers with high accuracy. In particular, it has high utility as an inspection device for micro bumps used in the manufacture of multilayer LSIs. Furthermore, since the displacement distribution and the two-dimensional image information in the height direction of the sample surface are output only by scanning the sample surface once, the sample can be inspected at high speed. Furthermore, since inspection can be performed with a resolution as high as that of the interferometer without using an interferometer, the manufacturing cost is greatly reduced and the assembling workability is also greatly improved.

In the inspection apparatus according to the present invention , the signal processing circuit further includes means for outputting a sum signal of output signals of the light receiving elements aligned with each other in a direction orthogonal to the arrangement direction of the light receiving elements of the first and second line sensors. And a second comparison means for comparing the addition signal with the reference signal, and the defect determination is performed based on the output result from the second comparison means. In the inspection apparatus according to the present invention, the height displacement of the sample surface is detected by forming a differential signal of the output signal of the corresponding light receiving element, and the sum signal of the output signal of the corresponding light receiving element is formed by forming the addition signal of the output signal of the corresponding light receiving element. Two-dimensional image information is output. Therefore, it is possible to simultaneously inspect whether or not a predetermined member is formed at a predetermined position on the sample surface along with the displacement in the height direction of the sample surface. For example, when inspecting a semiconductor wafer having a large number of micro bumps formed on the surface, it is possible to inspect whether or not bumps having a predetermined height are formed, and whether or not each bump is formed at a predetermined position at the same time. It is possible to inspect.

In the three-dimensional measuring apparatus according to the present invention, it is possible to output both the three-dimensional shape information and the two-dimensional image information of the sample surface only by scanning the sample surface once with a linear illumination beam. As a result, the sample surface can be inspected at high speed.
In addition, since the displacement distribution in the sample surface height direction can be detected with a resolution of several nanometers without using an interferometer, a three-dimensional measuring apparatus and inspection apparatus in which manufacturing workability and manufacturing cost are significantly reduced are provided. Realized.

  FIG. 1 is a diagram showing an example of a three-dimensional measuring apparatus according to the present invention. The illumination light emitted from the illumination light source 1 is projected toward the slit 3 through the condenser lens 2. As the illumination light source, for example, a xenon lamp, a mercury lamp, a halogen lamp, a laser, or the like can be used. The slit 3 has an elongated opening 3a having a width of about 5 μm extending in a direction perpendicular to the paper surface. Therefore, a linear illumination beam extending from the slit 3 in a direction orthogonal to the paper surface (X direction) is emitted. The line-shaped illumination beam is converted into a focused line-shaped illumination beam via an illumination optical system including the first and second lenses 4 and 5 and is incident on the sample 6 obliquely. The incident angle of the illumination beam with respect to the sample surface is set to 45 °, for example, and the beam width of the linear illumination beam on the sample surface is set to 5 μm, for example.

  The sample 6 is held on the XY stage 7, and the surface of the sample 6 is scanned two-dimensionally by the focused line-shaped illumination beam by scanning the XY stage 7 in the Y direction orthogonal to the X direction. Become. The line-like reflected beam emitted from the surface of the sample 6 forms an image on the image plane via an image forming optical system including the objective lens 8 and the image forming lens 9. The light detection means is arranged on this image plane. Therefore, a slit image, which is an image of the opening 3a of the slit 3, is formed on the light incident surface of the light detection means. In this example, two line sensors 10 and 11 are used as the light detection means. The first and second line sensors 10 and 11 have a plurality of (for example, 1024) light receiving elements arranged in the extending direction of the linear reflected beam, that is, the X direction, and are arranged so as to be directly adjacent to each other. . Therefore, the boundary line of these line sensors coincides with the extending direction of the reflected beam, and the light incident surface is located on the image forming surface of the image forming optical system. The light receiving elements of the first and second line sensors 10 and 11 face each other across the boundary line of the line sensor, and the i-th light receiving element is located at the same position in the X direction.

  The optical element disposed in the optical path from the illumination light source 1 to the two line sensors 10 and 11 is mounted on the support member 12. The support member 12 is movably supported by two rails (not shown) extending in a direction (Z-axis direction) orthogonal to the sample support surface of the stage 7 and includes an eccentric cam and a servo motor. The mechanism 13 is connected. The servo motor is driven by a drive signal supplied from the drive circuit 14, and is displaced in the Z-axis direction according to a focus error signal described later. Therefore, by performing focus control based on the focus error signal, it is possible to track the linear illumination beam on the sample surface.

  An XY drive mechanism 15 is connected to the XY stage 7 and moves in the X and Y directions by a drive signal supplied from a drive circuit. Therefore, the sample 6 is scanned two-dimensionally by the line-shaped illumination beam. Further, the XY stage 7 is provided with a position detector 16 to detect the position of the stage in the X direction and the Y direction, and supply it to the signal processing circuit as a stage position detection signal.

    FIG. 2 shows the form (slit image) of the reflected beams formed on the two line sensors 10 and 11. The three-dimensional measuring apparatus according to the present invention detects the displacement in the direction perpendicular to the sample surface (the height direction and the depth direction of the sample surface: the Z-axis direction) using the so-called “optical lever” principle. That is, in FIG. 1, when the surface of the sample 6 is displaced in the height direction or the depth direction, for example, if a minute convex portion exists on the sample surface or a minute concave portion exists on the sample surface, the light is emitted from the portion. The reflected beam is displaced according to the amount of displacement in the height direction, and the slit image is displaced in a direction orthogonal to the boundary line between the two line sensors. The displacement of this slit image is shown in FIGS. In FIG. 2, a broken line indicates a slit image formed by the reflected beam. FIG. 2A shows the illumination beam tracking on the sample surface. In this case, the center of the slit image by the reflected beam is located on the boundary line 20 between the two line sensors. On the other hand, when the sample surface is displaced in the height direction, the slit image is displaced in the direction b in FIG. 1, and is displaced on the light detection means as shown in FIG. 2B. When the sample surface is displaced in the depth direction, the slit image is displaced in the direction a in FIG. 1, and is displaced on the light detection means as shown in FIG. Therefore, the difference signal (a) between the output signal a-i from the light receiving element 10-i of the first line sensor 10 and the output signal bi from the corresponding light receiving element 11-i of the second line sensor 11 By detecting -i-b-i), the height information of the sample surface can be obtained. In this case, since the displacement direction of the slit image is reversed between the case where the sample surface is convex and the case where it is concave, it can be determined from the sign of the difference signal whether it is convex or concave. Further, since the array position of each light receiving element indicates the position in the X direction, a displacement distribution in the height direction of the sample surface is output based on the array position information of the light receiving element and the difference output.

Next, the simulation result about the sensitivity with respect to the height direction displacement of the sample surface will be described. FIG. 3A shows the simulation result of the light amount profile of the slit image formed on the light incident surfaces of the two line sensors. The horizontal axis indicates the relative position in the displacement direction of the slit image on the image plane, and the vertical axis indicates the relative light quantity value. The parameters used for the simulation are as follows.
Width of opening of slit 3: 5 μm
Illumination wavelength: 550 nm
Numerical aperture (NA) of objective lens: 0.13
Horizontal magnification: 1
The simulation result is shown in FIG. 3A.

FIG. 3B shows a theoretical sensitivity range when the width of the light receiving element is set to 5 μm. The output ai of the light receiving element of the first line sensor and the first output with respect to the displacement amount of the slit image on the imaging surface. The change of the difference value (ai-bi) with the output bi of the corresponding light receiving element of 2 line sensors is shown. The vertical axis indicates the difference value as the relative light quantity, and the horizontal axis indicates the relative position on the light incident surface. The distance from the positive peak to the negative peak of the difference value is 6.4 μm. In this range, the difference value changes almost linearly. Therefore, the displacement distribution in the height direction of the sample surface can be measured in this sensitivity range. If the incident angle of the illumination beam on the sample surface is 45 °, 6.4 × (1 / √2)
≈4.5 μm, and the displacement of the sample surface in the height direction over 4.5 μm is measured. FIG. 4 shows the relationship between the displacement in the height direction of the sample surface and the displacement on the imaging plane. When the gradation is set to 10 bits, the resolution is
4500 nm ÷ 1023≈4.4 nm. That is, the displacement in the height direction of the sample surface can be measured with a resolution of the order of nm.

  Here, the position information in the X direction on the sample surface is specified by the arrangement position of the light receiving elements of the line sensor, and the position information in the Y direction is specified by the position detection signal output from the position detector 16 provided on the stage. The displacement in the vertical direction is specified by the difference signal of the light receiving elements of the two line sensors. Therefore, the three-dimensional shape of the sample surface is measured by using these output information.

  Next, a two-dimensional image of the sample surface will be described. In the present invention, a linear illumination beam extending in the X direction is used, and the stage 7 is moved in the Y direction to scan the sample surface two-dimensionally. At this time, the position information in the X direction is specified by the arrangement position of the light receiving elements of the line sensor, and the position in the Y direction is specified by the position information of the stage 7. Accordingly, two light receiving element addition outputs (ai + bi) corresponding to each other of the two line sensors 10 and 11 are set as luminance values, the arrangement position of the light receiving elements of the line sensor is set as the position coordinate in the X direction, and the position of the stage. By using as the position coordinates in the Y direction, a two-dimensional image of the sample surface is captured. The two-dimensional image of the sample surface provides useful information when, for example, members having different reflectances exist on the sample surface. For example, when metal wiring and bumps are formed on the surface of a semiconductor wafer, the width and form of the metal wiring and bumps can be observed from the two-dimensional image information. Further, by using the pattern matching method, it is possible to inspect whether or not bumps or metal wirings are formed at predetermined positions.

  Furthermore, a three-dimensional image including the characteristics of the sample surface is measured by combining the displacement output in the height direction obtained from the difference value between the corresponding two light receiving elements and the two-dimensional image output.

  FIG. 5 is a block diagram illustrating an example of a signal processing circuit that outputs image information on the sample surface. The output signals of the pixels of the first line sensor 10 are sequentially read out, amplified by the preamplifier 31, converted into a digital signal by the A / D unit 32, and supplied to the subtracter 33 and the adder 34, respectively. Similarly, the output signal of each pixel of the second line sensor 11 is sequentially read out, amplified by the preamplifier 35, converted into a digital signal by the A / D unit 36, and supplied to the subtracter 33 and the adder 34, respectively. To do. The subtracter 33 forms a difference between the output signal of the pixel of the first line sensor and the output signal of the corresponding pixel of the second line sensor, and supplies the difference value to the first image memory 37. In the adder 34, the output signal of the pixel of the first line sensor and the output signal of the corresponding pixel of the second line sensor are added, and the added output is supplied to the second image memory 38. In the first and second image memories 37 and 38, a stage position counter 40 indicating a count signal from a pixel counter 39 that outputs position information of each pixel of the two line sensors and position information of the XY stage 7 in the Y direction. The count signal from is also supplied as address information for each pixel.

Therefore, the height information or depth information of the sample surface is stored for each pixel in the first image memory 37, and the three-dimensional shape information of the sample surface is output from the first image memory 37. The second image memory 38 stores the two-dimensional luminance information of the sample surface for each pixel, and the second image memory 38 outputs the two-dimensional image information of the sample surface.
Although the difference value (ai-b-i) is used as the height information of each pixel, a difference value normalized by dividing the difference value by the added value can also be used.

  The present invention can be realized not only as a three-dimensional measuring apparatus but also as an inspection apparatus for inspecting a sample surface. Hereinafter, an embodiment of a signal processing circuit when used as an inspection apparatus will be described. FIG. 6 is a diagram illustrating an example of a signal processing circuit of the inspection apparatus. In addition, the same code | symbol is attached | subjected and demonstrated to the component same as the component used in FIG. A difference signal (ai-bi) corresponding to the displacement amount in the height direction of the sample surface sequentially output from the subtractor 33 is supplied to the moving average circuit 50 to obtain a moving average in the height direction. The output is supplied to the difference detection circuit 51. The output of the subtracter 33 is also supplied to the difference detection circuit 51. The difference detection circuit 51 detects the difference between the moving average of the displacement in the height direction and the position in the height direction of each pixel and the moving average, and supplies the output to the first comparator 52. In the first comparator, when the difference between the moving average of the height position of the sample surface and the height position of each pixel exceeds a predetermined threshold value, it is determined that the pixel portion has a concave or convex defect. And stored in the defect memory 53.

  The defect memory 53 is also supplied with position information in the X direction output from the pixel counter 39 and position information in the Y direction output from the stage position counter 40. Therefore, the detected defect and its address are stored in the defect memory 53.

  The output of the subtractor 33 is supplied to the low-pass filter 54, the low frequency component in the height direction of the sample surface is detected, the output is supplied to the second comparator 55, and compared with a predetermined threshold value. If it exceeds, it is determined as a defect. This defect determination output is also supplied to the defect memory 53. Since the output from the low-pass filter outputs information corresponding to the waviness of the sample surface, the defect is judged by comparing the output of the low-pass filter with a threshold value to determine a defect over a relatively wide range of the sample surface. Information is obtained.

The output signals of the subtractor 33 and the adder 34 are supplied to the normalization circuit 56, and the normalized height direction displacement amount (ai-bi) / (ai + bi) of each pixel is detected. To do. The normalized amount of displacement in the height direction is compared with a threshold value in the third comparator, and if the threshold value is exceeded, a defect is determined. In this case, fine unevenness on the sample surface can be detected as a defect.
Since the output signal from the normalization circuit 56 corresponds to the focus error signal, a drive signal for the drive mechanism 13 that drives the optical system support member 12 in the Z-axis direction can be generated based on the output signal. .

  The addition output of the adder 34 is supplied to the pattern matching circuit 58. The pattern matching circuit 58 is also supplied with a reference image signal that is reference image information of the sample surface output from the reference image generator 59, and matches the added output corresponding to the two-dimensional image information of the sample with the reference image information. Seeking sex. The obtained correlation value is supplied to the fourth comparator 60, and when the correlation value exceeds a predetermined threshold, it is determined as a defect. By this defect inspection, it is detected whether or not a predetermined pattern of a predetermined portion on the sample surface is formed.

  In the defect inspection method described above, defect determination is performed by comparing the displacement of the sample surface in the height direction and two-dimensional image information in one sample with a predetermined threshold value. When a large number of elements or chips or dies are formed therein, it is possible to perform defect determination by a die-to-die comparison method or a chip-to-chip comparison method. Furthermore, it is also possible to perform defect determination by die-to-database comparison inspection, which is a comparison inspection with design information on the sample surface stored in the database. For example, it is also possible to use the output signal from the low-pass filter or the output signal from the normalization circuit as the reference signal for comparison inspection, and determine the defect by die-to-die or chip-to-chip comparison.

  The inspection apparatus according to the present invention is suitable for inspecting, for example, warpage and flatness of a semiconductor wafer. Furthermore, it is also suitable for inspection of bumps formed on the wafer surface. In particular, since the three-dimensional measuring apparatus according to the present invention has a resolution in the height direction of several nanometers, it inspects micro bumps formed on a wafer used for manufacturing a stacked LSI at high speed and at high speed. It is effective as an inspection device.

  FIG. 7 is a diagram showing a modification of the optical system of the three-dimensional measuring apparatus or inspection apparatus according to the present invention. The same components as those used in FIG. 1 are described with the same reference numerals. In this example, the beam splitter 70 is disposed between the imaging optical system and the light detection means. The beam splitter 70 is constituted by a beam splitter in which three columnar triangular prisms are combined, and each triangular prism 71 to 73 is a prism having an isosceles triangular section with an apex angle of 90 °. A part of the line-like reflected beam from the sample surface is transmitted at the interface between the first prism 71 and the second prism 72, and the remaining beam part is reflected. A part of the transmitted beam component is transmitted at the interface between the second prism 72 and the third prism 73, and the remaining beam part is reflected. The first line sensor 10 and the second line sensor 11 are arranged on a plane conjugate with the imaging plane of the imaging optical system. In accordance with the displacement of the sample surface in the height direction, the slit image formed on the line sensor 10 is displaced in the direction of the arrow a or b, and the slit image formed on the line sensor 11 is displaced in the direction of the arrow c or d. . Therefore, by detecting the difference between the output signals between the corresponding light receiving elements of the two line sensors, the displacement in the height direction of the sample surface is measured, and the sum of the output signals of the corresponding light receiving elements is calculated. By detecting, a two-dimensional image of the sample surface is formed.

  Reflected by the interface between the first prism 71 and the second prism 72, reflected by the light incident surface 71a of the first prism, and reflected on the optical path of the reflected beam from the sample surface emitted from the light emitting surface 71b. Two photodiodes 74a and 74b for autofocus pull-in are arranged. These two photodiodes have a relatively large light receiving area, and focus control can be performed based on the difference signal.

It is a diagram which shows the structure of the optical system of the three-dimensional measuring apparatus by this invention. It is a diagram which shows the form of the slit image formed on two line sensors. It is a graph which shows the profile and theoretical sensitivity of the optical image formed on two line sensors. It is a diagram which shows the relationship between the displacement of the height direction of a sample surface, and the displacement of a reflected beam. It is a figure which shows an example of the signal processing circuit of the three-dimensional measuring apparatus by this invention. It is a figure which shows an example of the signal processing circuit of the test | inspection apparatus by this invention. It is a figure which shows the modification of an optical system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2 Condensing lens 3 Slit 4 Collimator lens 5 Illumination lens 6 Sample 7 Stage 8 Objective lens 9 Imaging lens 10 1st line sensor 11 2nd line sensor 12 Support member 13 Drive mechanism 14 Drive circuit 1
15 XY drive mechanism 31, 35 Preamplifier 32, 36 A / D converter 33 Subtractor 34 Adder 37, 38 Image memory 39 Pixel counter 40 Stage position counter

Claims (5)

A light source that generates illumination light, and a light source device that has a slit in which an elongated opening is formed, and that generates a linear illumination beam from the slit;
An illumination optical system that projects a linear illumination beam emitted from the light source device obliquely to the sample surface;
An imaging optical system that collects a linear reflected beam emitted from the sample surface and forms an image of the slit on the imaging surface;
A light detection means disposed on the imaging surface of the imaging optical system and receiving a line-shaped reflected beam forming the slit image;
A stage for supporting the sample and moving the sample in a direction perpendicular to the extending direction of the linear illumination beam;
A signal processing circuit for outputting displacement information in the height direction of the sample surface and two-dimensional image information of the sample surface based on an output signal from the light detection means,
The light detection means includes a first line sensor and a second line sensor that are arranged in parallel to each other on the imaging plane and each have a plurality of light receiving elements arranged along the extending direction of the incident line-shaped reflected beam. Have
The light receiving element of the first line sensor and the light receiving element of the second line sensor are aligned with each other in a direction orthogonal to the arrangement direction thereof,
The signal processing circuit includes means for outputting a difference signal between output signals of light receiving elements aligned with each other in a direction orthogonal to the arrangement direction of the light receiving elements of the first and second line sensors, and means for outputting an addition signal. A three-dimensional measuring apparatus that outputs displacement information in the height direction of the sample surface based on the difference signal and outputs two-dimensional image information of the sample surface based on the addition signal.   The three-dimensional measuring apparatus according to claim 1, wherein the first and second line sensors are arranged so as to be directly adjacent to each other on the imaging surface of the imaging optical system, and receive each light of the two line sensors. The three-dimensional measuring apparatus, wherein the elements are arranged so as to face each other across the boundary line of the line sensor.   3. The three-dimensional measuring apparatus according to claim 1, further comprising stage position detection means for detecting the position of the stage, from position information of the light receiving elements of the first and second line sensors and stage position detection means. Three-dimensional measurement characterized in that address information on the sample surface is output based on the output stage position information, and a displacement distribution in the height direction of the sample surface is output based on the address information and the difference signal output. apparatus.   4. The three-dimensional measuring apparatus according to claim 1, wherein the light source device, the illumination optical system, the imaging optical system, and the light detection means are held on a support member, and a sample stage is attached to the support member. A drive mechanism that drives in a direction orthogonal to the sample support surface is connected, a focus error signal is formed from the difference signal, and the drive mechanism is operated based on the obtained focus error signal to perform focus control. Characteristic three-dimensional measuring device. An inspection apparatus for optically inspecting a sample surface,
A light source that generates illumination light, and a light source device that has a slit in which an elongated opening is formed, and that generates a linear illumination beam from the slit;
An illumination optical system that projects a linear illumination beam emitted from the light source device obliquely to the sample surface;
An imaging optical system that collects a linear reflected beam emitted from the sample surface and forms an image of the slit on the imaging surface;
A light detection means disposed on the imaging surface of the imaging optical system and receiving a line-shaped reflected beam forming the slit image;
A stage for supporting the sample and moving the sample in a direction perpendicular to the extending direction of the linear illumination beam;
Comprising a signal processing circuit for outputting a defect detection signal based on the output signal from said light detecting means,
The light detection means includes a first line sensor and a second line sensor that are arranged in parallel to each other on the imaging plane and each have a plurality of light receiving elements arranged along the extending direction of the incident line-shaped reflected beam. Have
The light receiving element of the first line sensor and the light receiving element of the second line sensor are aligned with each other in a direction orthogonal to the arrangement direction thereof,
The signal processing circuit outputs a difference signal between output signals of the light receiving elements aligned with each other in a direction orthogonal to the arrangement direction of the light receiving elements of the first and second line sensors, and the difference signal as a reference signal First comparison means for comparing, means for outputting an addition signal of output signals of light receiving elements aligned with each other in a direction orthogonal to the arrangement direction of the light receiving elements of the first and second line sensors, and the addition signal as a reference and a second comparator means for comparing the signals, the inspection apparatus characterized by determining the defect based on the comparison result by the comparison result and the second comparison means by said first comparison means.

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