JP2013002819A - Flatness measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve measurement accuracy and a region resolution in a flatness measuring device using a Shack Hartmann wavefront sensor.SOLUTION: A flatness measuring device comprises a light source 1 which emits primary light flux B1 that is light flux which can be made parallel, light guide means 2 which guides the primary light flux B1 emitted from the light source 1 to a measurement target region Ar, reflects the primary light flux and outputs secondary light flux B2 that is the reflected light flux as light flux having a flat wavefront, a lens array 3 which is provided to be orthogonal with the secondary light flux B2 outputted from the light guide means 2, an aperture member 4 which is provided on an incident side optical axis of each of lenses constituting the lens array 3 and makes a diameter of light incident to each of the lenses smaller than that of the lens, respectively, photodetection means 5 which detects separated light beams D that passes through the lens array 3 and is separated for each lens, and a flatness calculation section 6 which calculates a value relating to flatness in the measurement target region AR on the basis of a position or inclination of each of the separated light beams D obtained in the photodetection means 5.

Description

  The present invention relates to a flatness measuring device that measures the flatness of a surface of a workpiece such as a semiconductor wafer.

  In an industrial product such as a semiconductor wafer in which fine warpage or unevenness of the surface is a problem, the flatness of the surface is inspected. As a flatness measuring apparatus for this purpose, for example, a device using a Shack-Hartmann wavefront sensor as shown in Patent Document 1 is known. In this apparatus, the surface flatness of a wafer or an optical component is measured by directing light reflected from a measurement target surface to a wavefront sensor.

  This wavefront sensor is provided with a large number of small lenses laid out in an array as shown in FIG. 1, and light reflected from the measurement target surface (hereinafter also referred to as incident light) passes through the small lenses. However, it is configured to form an arrayed light spot. If the wavefront of the incident light is perpendicular to the lens optical axis, the light spot is formed on the lens optical axis, but, as shown in FIG. When the wavefront of the incident light is inclined, the position of the light spot is shifted from the lens optical axis.

  Therefore, the flatness of the measurement target surface is measured by measuring this deviation amount with a two-dimensional photodetector (for example, an area image sensor configured by two-dimensionally arranging photodetection elements such as a CCD and a CMOS).

  More specifically, for example, as shown in FIG. 3, the measurement target region is divided into adjacent rectangular unit regions, and almost all of the light reflected by each unit region is guided to each small lens. It is burned. Then, the light reflected by the unit area hatched in FIG. 3 passes through the corresponding small lens and is condensed on the light detection surface of the area image sensor as shown in FIG. Since the condensed position can be specified from the output of the area image sensor, the deviation amount Δe is known based on the position, and the flatness for each unit region is calculated. As described above, the flatness is obtained for each unit region, and each obtained value is a value indicating the average flatness averaged for each unit region.

Special table 2003-503726 gazette

  However, with the above-described configuration, light is transmitted also to the peripheral portion of each small lens, and spot light is blurred or shifted due to the influence of aberration at the peripheral portion, which adversely affects measurement accuracy. There is.

  In actual measurement, photoelectric conversion time, readout time, and the like in the photodetector are required until the position of the light spot is specified. However, in the state where the inspection object is moving, such as when measuring the flatness of the wafer during CVD, if the unit area described above is adjacent, during the flatness measurement related to the unit area, There is also a problem that the reliability of the measured value is lowered because the next unit region moves and receives the reflected light.

  Furthermore, in the conventional device, even when trying to measure the flatness at a pinpoint by reducing the unit area, the unit area cannot be reduced more than a predetermined due to the restriction of the size of the lens. There is also a problem that the resolution cannot be easily improved.

  SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and a main object of the present invention is to dramatically improve measurement accuracy and area resolution with a simple configuration in a flatness measuring apparatus using a Shack-Hartmann wavefront sensor. It is what.

That is, the flatness measuring apparatus according to the present invention measures the flatness of a measurement target region in an inspection product such as an industrial product, and has the following configuration requirements.
(1) A light source that emits a primary light beam that is a collimated light beam, such as a light beam having a substantially planar, substantially spherical, or substantially cylindrical wavefront. In addition, the degree of parallelization in “parallelization possible” is determined by the measurement accuracy of flatness.
(2) When the primary light beam emitted from the light source is guided and reflected to the measurement target region, and the secondary light beam that is the reflected light beam is a plane that satisfies the predetermined standard, Light guide means for outputting as a light beam having a substantially parallel or substantially planar wave front. Here, “substantially parallel” refers to a degree of parallelism that does not allow light to be incident on an adjacent lens to enter in a secondary light beam incident on a lens array, which will be described later, via an aperture member. (3) A lens array provided so as to be orthogonal to the secondary light beam output from the light guide means if the measurement target region is a plane that satisfies a predetermined standard.
(4) It is provided on the incident side or the emission side of each lens constituting the lens array so that the light diameter incident on each lens or emitted from each lens is smaller than the effective diameter of each lens, in other words, An aperture member that causes the outer cross-sectional contour of light when entering or exiting each lens to be inside the substantial outer contour of the lens.
(5) Light detecting means for detecting the position of separated light that is light separated for each lens through the lens array (6) Based on the inclination or position of each separated light obtained by the light detecting means, A flatness calculation unit that calculates a value related to the flatness of the measurement target region. In addition, the value relating to the flatness is a value calculated from these in addition to the inclination of the surface, the radius of curvature, the surface roughness, etc. For example, if the inspection object is a wafer or the like, the Sori value, Warp value, Bow value Including.

  In such a case, the aperture member blocks the light emitted through the peripheral portion of each lens, and uses the light only at the central portion of each lens. , And the light intensity distribution of the separated light on the light receiving surface of the light detecting means becomes close to an ideal curve when there is no aberration in the lens. As a result, the position measurement accuracy of the separated light is improved, and as a result, the flatness can be measured with higher accuracy.

  Further, the fact that the peripheral portion of the separated light is cut by the aperture member means that the unit regions in the measurement target region from which the cut separated light originates are separated from each other. Then, even if the inspection object is moved by appropriately setting the separation distance between the unit areas, that is, the cutting area by the aperture member, the movement of the inspection object is influenced by the adjacent separated light during the measurement. It is possible to eliminate problems such as More specifically, for example, a region (hereinafter also referred to as a unit measurement surface) that is a unit for which the flatness is to be known is set to a corresponding number of lens arrays, and the unit measurement surfaces are rectangular. In the unit region of the flatness detecting device, the peripheral portion of the reflected light from the unit measurement surface is scraped by the aperture member, so that the unit region has a smaller area than the unit measurement surface. Even if the inspection object moves in this state, if the unit area is set within a range that does not exit the unit measurement surface within the time required for one measurement, the unit may be slightly averaged due to movement. The typical flatness of the measurement surface can be reliably measured without being affected by the adjacent unit measurement surface.

  Furthermore, the fact that the peripheral portion of the separated light is cut by the aperture member means that the unit area from which the cut separated light is derived also becomes smaller. Therefore, it is possible to measure the flatness with a smaller area than before, and to improve the region resolution.

  If the light detection means is an area image sensor in which light receiving elements are spread in a plane, and the light receiving surface is set at a position shifted in the optical axis direction from the convergence position of the separated light, the light spot diameter is widened. Therefore, since the separated light is dispersed to many light receiving elements, saturation of each light receiving element can be avoided and a wide measurement range can be taken. The optical axis position is calculated based on the light intensity signal values from a plurality of light receiving elements. However, since the number of the light receiving elements increases, the calculation accuracy of the optical axis position can be improved, and the flatness can be improved. It can measure with high accuracy.

  Examples of the aperture member having a simple configuration include a thin plate-like member in which a light transmission window having a diameter smaller than the actual diameter of the lens is provided at a position corresponding to the optical axis of each lens.

  In order to avoid an adverse effect on the measurement due to light diffraction at the aperture member, the light transmission window has the largest light transmittance at the center portion that intersects the lens optical axis, and is directed toward the periphery. Accordingly, it is preferable that the light transmittance is changed in the middle, for example, the light transmittance is reduced.

  As a specific flatness calculation method, a standard position that is a position of each separated light obtained when the measurement object region is irradiated with the primary light on a standard inspection object having a flatness within a specified range should be measured. An example of calculating a value related to the flatness of the measurement target region based on a deviation from a measurement position that is a position from each separated light obtained when the inspection object is irradiated with the primary light can be given.

A specific example of the light source is a laser that emits coherent parallel light.
In order to be able to cope with a measurement target region having a large area, the measurement target region and the flatness measuring apparatus may be relatively moved to scan the measurement target region.

  In order to measure the measurement target region more precisely, the relative movement distance until the next measurement may be set smaller than the separation distance between the unit region and the adjacent unit region. This is because it is possible to measure even between unit regions that cannot be filled by one measurement.

  According to the present invention configured as described above, in the flatness measuring apparatus using the Shack-Hartmann wavefront sensor, the measurement accuracy and the area resolution can be dramatically improved with a simple configuration for the reasons described above.

Schematic diagram of a flatness measuring apparatus using a conventional Shack-Hartmann wavefront sensor. Schematic diagram of a flatness measuring apparatus using a conventional Shack-Hartmann wavefront sensor. The top view which shows the measurement object area | region and unit area | region in the target object in the past. The top view which shows the light spot condensed on the image area sensor in the past. The whole schematic diagram which shows the flatness measuring apparatus in 1st Embodiment of this invention. The disassembled perspective view which shows the aperture member of the same embodiment, a lens array, and an area image sensor. The typical longitudinal cross-sectional view explaining the positional relationship of the aperture member in the same embodiment, a lens array, and an area image sensor. The top view which shows the state which looked at the area image sensor in the embodiment from the light-receiving surface. The top view which shows the relationship with the measurement object area | region in the same embodiment, a unit area | region, and a unit measurement surface. The whole schematic diagram which shows the flatness measuring apparatus in 2nd Embodiment of this invention. The typical longitudinal cross-sectional view explaining the positional relationship of the aperture member in the 3rd Embodiment of this invention, a lens array, and an area image sensor. The top view which shows the light spot condensed on the image area sensor in 1st Embodiment of this invention. The top view which shows the light spot condensed on the image area sensor in 3rd Embodiment of this invention. The top view which shows the aperture member in 4th Embodiment of this invention. The top view which shows the aperture member in 1st Embodiment of this invention. The top view which shows the aperture member in the modification of the said 4th Embodiment. The whole schematic diagram which shows the flatness measuring apparatus in 5th Embodiment of this invention. The whole schematic diagram which shows the flatness measuring apparatus in 6th Embodiment of this invention. The whole schematic diagram which shows the flatness measuring apparatus in other embodiment of this invention. The whole schematic diagram which shows the flatness measuring apparatus in other embodiment of this invention. The whole schematic diagram which shows the flatness measuring apparatus in other embodiment of this invention.

  Hereinafter, an embodiment of a flatness measuring apparatus 100 according to the present invention will be described with reference to the drawings.

<First Embodiment>
The flatness measuring apparatus 100 is incorporated in a part of a semiconductor manufacturing system such as CVD (MOCVD), for example, and measures the flatness of a measurement target area AR set on the surface of a wafer W that is a flat inspection object. As shown in FIGS. 5 and 6, etc., the light source 1 that emits a primary light beam B1 that is a light beam having a planar wave front, and the primary light beam B1 emitted from the light source 1 are used as the measurement target region. A light guide means 2 composed of an optical member for guiding and reflecting to the AR and outputting the reflected secondary light beam B2 as a light beam having a planar wavefront; and the optical axis of the secondary light beam B2. The lens array 3 provided so as to be orthogonal to each other, and provided on the incident side optical axis of each lens 31 constituting the lens array 3, the light diameter incident on each lens 31 is larger than the effective diameter of each lens 31. Make smaller A detection member 5 for detecting the position of the separation light D, which is the light separated for each lens 31 through the lens array 3, and the separated light D obtained by the light detection means 5; A flatness calculating unit 6 for calculating a value related to the flatness of the measurement target area AR based on the position;

Each part will be described.
Here, the light source 1 is a laser that emits primary light that is a coherent, single-wavelength parallel light beam, but may also emit white light using an LED or the like.

  Here, the light guide means 2 is composed of the following components. That is, the first lens member 21 that expands the primary light beam B1 output from the laser 1, and the half mirror that reflects the expanded primary light beam B1 so that the optical axis thereof is perpendicular to the measurement target area AR of the wafer W. The second lens member 22 that converts the primary light beam B1 reflected by the beam splitter 23 into a parallel light beam having a cross section sufficient to cover the measurement target area AR, that is, a light beam having a planar wavefront, and the measurement target A secondary light beam which is provided on the optical axis of the light beam reflected vertically in the area AR and passed through the second lens member 22 and the beam splitter 23, and which is a parallel light beam, that is, a light beam having a planar wavefront. It is the 3rd lens member 24 converted into B2.

  It should be noted that the function of outputting the secondary light beam B2 having a planar wave front in the light guide means 2 can be understood by those skilled in the art, and is a function when the measurement target area AR is a plane. It is. In actual flatness measurement, when the measurement target area AR is uneven or inclined, the wave front of the secondary light beam B2 corresponding to that portion is not flat. It is the Shack-Hartmann's plane measurement principle that only this part is detected.

As shown in FIGS. 6 and 7, the lens array 3 is obtained by integrally arranging a plurality of small lenses 31 on one face plate portion of a rectangular (square) transparent plate 32. In this lens array 3, the light incident surface 3 a is set to the other face plate portion of the transparent plate 32, and this incident surface 3 a is orthogonal to the optical axis of the secondary light beam B <b> 2 output from the light guide means 2. Thus, the lens array 3 is arranged. The secondary light beam B2 incident on the lens array 3 passes through each lens 31 and becomes separated light D. The shape of the lens array 3 is not limited to this, and may be a circular shape, for example.
In FIGS. 6 and 7, etc., a lens having a flat incident side is used. However, a lens having a curved surface on the incident side may be used. In order to reduce the influence of aberration and the like, it is preferable that the incident side is a curved surface. In addition, both sides may be curved.

  The aperture member 4 has a thin sheet shape, and is attached to the incident surface 3a of the lens array 3 here. The aperture member 4 is provided with apertures 4a, which are circular light transmission windows centered on the optical axis of the lens 31, corresponding to each lens 31. The aperture 4a here is a through-hole, and transmits 100% of light. The diameter is set smaller than the lens diameter.

The shape of the aperture 4a may be a rectangle other than a circle, a polygon, or the like. Further, the aperture member 4 may be separated from the incident surface 3a.
In this embodiment, since the entrance surface 3a of the lens array 3 is a flat surface, the aperture member 4 can be disposed without providing a dedicated support member. However, when the exit surface of the lens array is a flat surface, etc. Then, the aperture member 4 may be attached to the emission surface. However, considering the points that are easily affected by aberrations, etc., and the fact that light may be refracted first and not enter the aperture, an aperture member must be provided on the incident surface side of the lens array. Is preferred.

  As shown in FIGS. 6 to 8, the light detection means 5 is an area image sensor in which light receiving elements 51 such as a CCD and a CMOS are laid in a vertical and horizontal plane. Here, the light detection means 5 is separated through the lenses 31. It is set so that the light receiving surface 5a of the area image sensor 5 is located at a position (focus position) where the separated light D is condensed. That is, when the separated light D that has passed through each lens 31 is received by the light receiving surface 5a, the light detecting means 5 receives an electrical signal (light) corresponding to the light intensity received by the light receiving element 51 at the light irradiation position. Intensity light) is generated, and by monitoring the light intensity signal of each light receiving element 51, it is possible to detect which position of the light receiving surface 5a is irradiated with the separated light D. is there.

  As shown in FIG. 1, the flatness calculator 6 is connected to the area image sensor 5 and is physically an electric circuit composed of, for example, a CPU, a memory, an AD converter, and the like. In terms of function, the flatness calculating unit 6 is functionally arranged in accordance with a program stored in the memory, and the CPU and its peripheral devices cooperate to receive the light receiving surface 5a of the separated light D that has passed through each lens 31. The separation light D in the measurement target area AR is derived based on the optical axis position calculation unit for calculating the optical axis position at and the deviation Δe (see FIG. 7) of the calculated optical axis position from the reference position. For example, the unit area U (see FIG. 9) is provided with an inclination calculation unit that calculates one of the flatnesses.

The operation of the flatness measuring apparatus 100 having such a configuration will be described below.
The primary light beam B1 emitted from the laser 1 becomes a primary light beam B1 that is expanded by the first lens member 21, is reflected by the beam splitter 23, and travels toward the measurement target area AR. On the way, it is made a parallel light beam by the second lens member 22, is reflected vertically by the measurement target area AR, and follows the same locus as before the reflection to the beam splitter 23. Then, the primary light beam B1 transmitted through the beam splitter 23 is collimated by the third lens member 24, guided to the lens array 3 through the aperture member 4, and separated into the separated light D corresponding to each lens 31. .

  Each separated light D is condensed on the light receiving surface 5a of the light detecting means 5, and a position on the light receiving surface 5a irradiated with the separated light D is detected by a light intensity signal from each light receiving element 51.

  Then, the optical axis position calculation unit analyzes the light intensity signal output from the light detection means 5, and calculates the optical axis position of each separated light D on the light receiving surface 5a. For example, the optical axis position is calculated by obtaining the barycentric position of the value of the light intensity signal from each light receiving element 51. Finally, based on the deviation Δe of the calculated (measured) optical axis position from the reference position, the overall inclination of the unit area U from which the separated light D is derived in the measurement target area AR. Calculate the angle.

There are other methods for calculating the optical axis position. For example, a mode is conceivable in which the peak position is obtained from the light intensity of each light receiving element 51 by fitting by the least square method or the like, and the peak position is set as the optical axis position.
Further, as the calculated flatness, in addition to the inclination angle of the unit region U described above, a radius of curvature, a planar roughness, or the like may be used.
Furthermore, when the flatness calculated in this way exceeds a certain threshold value, an informing unit for informing that effect may be provided.

  In such a case, the aperture member 4 blocks the light entering the peripheral portion of each lens 31 and guides the light only to the central portion, so that the aberration generated in the peripheral portion of each lens 31 is reduced. The light intensity distribution of the separated light D on the light receiving surface 5a of the light detecting means 5 becomes close to an ideal curve when there is no aberration in the lens. As a result, the position measurement accuracy and tilt measurement accuracy of the separated light D are improved, and as a result, the flatness can be measured with higher accuracy.

  Further, the fact that the peripheral portion of the separated light D is cut by the aperture member 4 means that the unit areas U in the measurement target area AR from which the cut separated light D originates are separated from each other as shown in FIG. become. Then, even if the inspection object is moved by appropriately setting the separation distance of the unit area U, that is, the cut area by the aperture member 4, the movement of the inspection object causes the adjacent separated light D to be measured. The problem of being affected can be eliminated.

  More specifically, referring to FIG. 9, for example, a region P (hereinafter also referred to as a unit measurement surface) P for which the flatness is to be known is set to a number corresponding to the arrangement of the lens array 3, and Assuming that the unit measurement surfaces P are set adjacent to each other in a rectangular shape, the unit region U by the flatness detecting device has a peripheral edge portion of the reflected light from the unit measurement surface P cut by the aperture member 4. The area is smaller than the unit measurement surface P. Even if the inspection object moves in this state, if the unit area U is set within a range that does not exit the unit measurement surface P within the time required for one measurement, there is some averaging due to movement. The representative flatness of the unit measurement surface P can be reliably measured without being affected by the adjacent unit measurement surface P at all.

Furthermore, when the peripheral part of the separated light D is cut by the aperture member 4, the unit region U from which the cut separated light D is derived also becomes smaller. Therefore, it is possible to measure the flatness with a smaller area than before, and to improve the region resolution.
In addition, since the parallel primary light beam B1 is irradiated perpendicularly to the measurement target area AR, there is an effect that measurement accuracy can be ensured even if the measurement target area AR is shifted in the optical axis direction of the primary light beam B1.

  In addition, this invention is not limited to the said embodiment. Other modified embodiments will be described below. In addition, the same reference numerals are assigned to members corresponding to the first embodiment.

Second Embodiment
For example, as shown in FIG. 10, a reference member R having a standard plane is provided so that either the inspection object W or the reference member R can be selectively irradiated with the primary light beam B1 and the standard plane is provided. The light beam reflected in step 1 may be guided to the aperture member 4 and the light detection means 5 as a standard secondary light beam in the same manner as the light beam from the measurement target area AR.

More specifically, here, the fourth lens member 9 is provided at a position opposed to the first lens member 21 and the beam splitter 23, and the primary light beam that has exited the first lens member 21 and passed through the beam splitter 23 is provided. B1 is collimated by the fourth lens member 9, that is, a light beam having a wavefront on a plane.
The reference member R is arranged on the optical axis of the light beam that has passed through the fourth lens member 9 so that the standard plane is orthogonal.

  Further, in order to selectively irradiate either the inspection object W or the reference member R with the primary light beam B1, the primary light beams B1 separated by the beam splitter 23, that is, the light beams reflected by the beam splitter 23 and directed toward the inspection object W. For example, mechanical or liquid crystal type shutters 81 and 82 are provided in the optical path of the primary light beam and the primary light beam that passes through the beam splitter 23 and travels toward the reference member R, and either one of the shutters 81 (82) is opened. The other shutter 82 (81) is configured to be closed.

Then, using the optical axis position of each separated light D when the reference member R is used as a reference position, the deviation from the measurement position that is the optical axis position at the time of actual measurement is obtained, and the flatness is calculated. .
With such a configuration, calibration and adjustment can be easily performed, so that it is possible to measure flatness with higher accuracy that can withstand aging.
In particular, as in a CVD (MOCVD) apparatus, an inspection object is contained in the chamber and a flatness measuring device is provided outside the chamber, and a light flux is applied to the inspection object from outside the chamber through a transparent window of the chamber. With the configuration to irradiate, the transparent window is gradually clouded due to aging, and the light beam is slightly bent or slightly scattered when passing through the transparent window. However, if this reference member R is provided, the difference between the measurement result of the reference member R and the measurement result of the inspection object W can be taken to cancel changes in the surrounding environment such as clouding of the transparent window. It is possible to measure well.

<Third Embodiment>
For example, as shown in FIG. 11, the position where the light receiving surface 5a is shifted from the convergence position of the separated light D in the optical axis direction, that is, the position where the light receiving surface is further away from the convergence position (the position may be closer). May be set. By doing so, the diameter of the light spot becomes wider (see FIG. 13) than the light spot on the light receiving surface in the first embodiment (see FIG. 12), but as is apparent from FIGS. In addition, since the light is dispersed in many light receiving elements 51, saturation of each light receiving element 51 can be avoided and a wide measurement range can be taken. The optical axis position of the separated light is calculated based on the light intensity signal values from the plurality of light receiving elements 51. However, since the number of the light receiving elements 51 is increased, the calculation accuracy of the optical axis position can be improved. .

<Fourth embodiment>
For example, as shown in FIG. 14, the aperture member 4 has a film shape, and in the light transmission window, the central portion that is a position intersecting with the lens optical axis has the largest light transmittance and is directed toward the peripheral portion. Accordingly, if the light transmittance is configured to be small, the influence of diffraction can be eliminated. Here, the central portion of the light transmission window 4a is set to 100% light transmittance, and the coating of the film is changed so that the light transmittance gradually decreases toward the peripheral edge.

That is, if the light transmission window 4a is a simple through hole as in the first embodiment, a light peak appears outside the light transmission window 4a as shown in FIG. However, the above-described configuration can reliably eliminate the peak.
The light transmittance may be changed stepwise as shown in FIG. 14 or may be changed continuously. Further, the light transmittance is not only reduced toward the peripheral portion, but there may be a portion that increases in the middle as shown in FIG. 16, for example. The point is that the light transmittance in the light transmission window may be changed from the center toward the outside so that the light intensity distribution obtained on the light receiving surface has a single peak.

<Fifth Embodiment>
In the above-described embodiment, a convex lens having a partial spherical surface is used for each lens member in the measurement target area AR. However, as shown in FIG. 17, for example, cylindrical lenses 21 ′ and 22 ′ (Fresnel type may be used). May be used to irradiate the measurement target area AR with a ribbon-shaped primary light beam B1, that is, a light beam B1 having a linear cross section. In this case, cylindrical lenses 23 'and 24' (may be Fresnel type) may be used on the side where the reflected secondary light B2 is received, and the lens array 3 may be one-dimensionally arranged along the linear direction of the light beam B2. . FIG. 16 shows a case where the inspection object W moves in a predetermined direction. The linear light beam is irradiated so as to be orthogonal to the moving direction (may be oblique). If the flatness is measured every time or a certain distance is moved, scanning is performed, so that the flatness can be measured in a planar shape as in the case of the two-dimensional arrangement. Become.

  This scanning concept may be applied to the first embodiment. As shown in FIG. 9, since there is a gap between the unit areas U, the flatness of the measurement target area AR is measured by measuring the flatness of the gap portion by moving the flatness measuring apparatus 100 or the inspection object little by little. You can create a detailed profile about.

<Sixth Embodiment>
The primary light beam B1 emitted from the light source 1 is not limited to a parallel light beam, that is, a light beam having a wavefront that is collimated, that is, a light beam having a partially spherical or partial cylindrical wavefront. For example, in FIG. 18, the measurement target area AR is irradiated with a light beam having a partially spherical wave front, that is, a light beam that expands, and the reflected light beam is collimated by a lens member and guided to the light detection means 5.

<Others>
17 and 19 that do not use a beam splitter are possible, and the cross-sectional area of the parallel light beam applied to the light detection means is more than the cross-sectional area of the parallel light beam applied to the measurement target region. It is not always necessary to make it as small as the form. For example, if the same area is used as shown in FIG. 20, it is theoretically possible to eliminate an intermediate lens member. That is, in FIG. 20, the secondary light beam B2 reflected from the irradiation target region is directly guided to the aperture member 4 to the lens array 3, and an optical member such as a lens or a reflector is not required between them. Are arranged only on the primary light beam B1 side.

  Further, as shown in FIG. 21, the light beam B2 reflected by the measurement target area AR may be further separated by another beam splitter and introduced into the film thickness meter 11 using the optical interference action. Here, a film thickness meter 11 is provided for each unit region U as shown in FIG. In addition, this type of film thickness meter 11 requires reference light separately. However, the light beam B1 from the light source 1 is separated by a beam splitter (not shown) and guided to each film thickness meter 11 via an optical system (not shown). I am doing so.

Similarly, since infrared light having a wavelength corresponding to the temperature is emitted from the measurement target area AR, the infrared light is separated for each unit area U, guided to the radiation thermometer 12, and detected. You may measure the temperature for every. In FIG. 19, a second lens array corresponding to the unit region U is provided in front of the radiation thermometer 12, and radiant infrared light from an appropriate representative point in each unit region U is received from each radiation thermometer 12. So that the temperature can be measured.
The separated light D may be separated by a beam splitter and guided to the film thickness meter 11 or the radiation thermometer 12.

In this way, the correlation between the flatness of each unit region U and the temperature or film thickness can be determined, and more effective CVD manufacturing conditions can be found.
In addition, a film thickness meter and a radiation thermometer may not be provided for each unit region, but both may be one, or one may be one and the other may be a number corresponding to the unit region.
Further, when the inspection object is moving, the flatness measuring device acquires an output from the position detecting means for detecting the position, posture, etc. of the inspection object, and the measurement target area AR and unit It is desirable to be able to identify the absolute position of the region U in the inspection object. For example, when a wafer which is an inspection object is contained in the MOCVD apparatus and the wafer rotates or revolves, the rotation angle and the center position of the wafer are position detecting means for detecting the rotation angle and the rotation angle. What is necessary is just to be able to identify which area | region of the wafer is measured with the value acquired sequentially from an encoder.

  In addition, the present invention is not limited to the above-described embodiments, and the respective partial configurations may be combined, and it goes without saying that various modifications can be made without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 100 ... Flatness measuring apparatus 1 ... Light source (laser)
2 ... light guide 3 ... lens array 31 ... lens 4 ... aperture member 4a ... light transmission window 5 ... light detection means 51 ... light receiving element 6 ... flatness Calculation unit AR ... Measurement target area B1 ... Primary light beam B2 ... Secondary light beam D ... Separated light U ... Unit area U

Claims (10)

It measures the flatness of the area to be measured in inspection products such as industrial products,
A light source that emits a primary light beam that can be collimated;
A light guide means capable of guiding and reflecting the primary light beam emitted from the light source to the measurement target region, and outputting the reflected secondary light beam as a substantially parallel light beam;
A lens array provided to be orthogonal to the secondary light beam output from the light guide means;
An aperture member that is provided on the incident side or the emission side of each lens constituting the lens array, and that makes the light diameter incident on each lens or emitted from each lens smaller than the diameter of each lens;
Light detecting means for detecting separated light that is light separated for each lens through the lens array;
A flatness measuring apparatus comprising: a flatness calculating unit that calculates a value related to the flatness of the measurement target region based on an inclination or position of each separated light obtained by the light detection means.   2. The flatness measuring apparatus according to claim 1, wherein the aperture member has a thin plate shape in which a light transmission window having a diameter smaller than the lens diameter is provided at a position corresponding to the optical axis of each lens.   3. The light transmission window is configured such that a central portion which is a position intersecting with a lens optical axis has the largest light transmittance, and the light transmittance is changed toward a peripheral portion. The flatness measuring apparatus as described.   The light detection means is an area image sensor in which light receiving elements are spread in a plane, and the light receiving surface is set at a position shifted in the optical axis direction from the convergence position of the separated light. Flatness measuring device.   The flatness calculation unit has a reference position that is a position in a light detection means of each separated light obtained when the primary light is irradiated to a standard inspection object whose measurement target area has a flatness within a specified range, A value related to the flatness of the measurement target region is calculated based on the deviation of each separated light obtained when the inspection object to be measured is irradiated with the primary light from the measurement position which is the position of the light detection means. The flatness measuring device according to any one of claims 1 to 4, wherein the flatness measuring device is one.   6. The flatness measuring apparatus according to claim 1, wherein the light source is a laser that emits coherent parallel light.   In the case where the inspection object is moved and provided with position detection means attached to the inspection object and detecting its position and / or posture, inspection object position information which is an output from the position detection means The flatness measurement according to any one of claims 1 to 6, further comprising: a measurement region specifying unit that specifies an absolute position of the measurement target region in the inspection object based on the inspection object position information. apparatus.   A flatness measuring method for measuring flatness using the flatness measuring device according to any one of claims 1 to 7, wherein the measuring target region and the flatness measuring device are relatively moved to scan the measuring target region. A flatness measuring method characterized by:   The plane according to claim 8, wherein a relative movement distance until the next measurement is set to be smaller than a separation distance between a unit region that is a partial region from which one separated light is derived in the measurement target region and an adjacent unit region. Degree measurement method.   9. The position and / or orientation of the inspection object is detected, and an absolute position of the measurement target region in the inspection object is specified based on inspection object position information that is information relating to the position and / or orientation. Or the flatness measuring apparatus according to 9.