JP2010169700A - Height measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure not only the height of the outermost layer, but also the height of the upper surface (or the lower surface) of the other layers of an inspection object, constituted by forming a transparent or translucent material layer on a material layer, in a single scanning/imaging process. <P>SOLUTION: A height measuring device is constituted to calculate the height of an inspection portion from the height position of focus plane FS, obtained corresponding to initially detected light quantity peak after starting reading of scanned image from a memory device 32. The height measuring device calculates the height of the focus plane corresponding to a light amount peak detected on and after a predetermined spot out of light amount peaks successively detected after starting reading the scanned images. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a height measuring apparatus that measures the height of a region to be examined with high accuracy using a confocal optical system.

  2. Description of the Related Art Conventionally, a shape measuring device using a confocal optical system is known as a device that can measure the shape of a minute test object with high accuracy. The confocal optical system is designed to obtain a high-contrast image by removing the light emitted from other than the focal plane (the focused surface) by placing a pinhole at the back focal position of the objective lens. Yes, if a scanning image (image data) of the test object is obtained by moving the focal plane of the confocal optical system relative to the test object by a certain amount in the height direction, Since an image in which only the portion that coincides with the focal plane becomes bright is obtained at each height, a highly accurate shape measurement result can be obtained by performing three-dimensional image processing on the image.

  Further, the shape measuring device using such a confocal optical system can also be used as a height measuring device for obtaining the height of an arbitrary part on the surface of the test object, and the measurement obtained thereby The result is very accurate. The height measurement of the test site using this shape measuring device is performed by acquiring and storing a scan image in the height direction including the test site, then sequentially reading the scan image to detect the light intensity peak, According to the procedure of obtaining the height of the test site from the position of the focal plane corresponding to (the position relative to the stage on which the test sample is placed).

JP 2002-13917 A

  However, when the height of the test site is measured according to the above procedure, the scanning image readout order is the acquisition order (the order in which the scanning image was obtained, that is, the order in which scanning in the height direction of the test object progressed). However, since reading of the scanned image ends when the light intensity peak is detected, the upper surface of one material layer is transparent or semi-transparent so that the test object can be seen in a semiconductor product or the like. If you want to measure not only the upper surface height of the upper layer but also the upper surface height of the lower layer, two scanning / imaging operations with different scanning directions are performed. A process was required.

  The present invention has been made in view of such problems, and a single scan / scan is performed on a test object in which a transparent or translucent material layer is formed on one material layer such as a semiconductor product. It is an object of the present invention to provide a height measuring device configured to measure not only the height of the outermost layer but also the height of the upper surface (or lower surface) of other layers in the imaging process.

  In order to achieve such an object, a height measuring apparatus according to the first aspect of the present invention provides a confocal optical system and a focal plane of the confocal optical system relative to the object in the height direction. Image acquisition means for acquiring image data of the test object at different height positions while moving, image storage means for storing the image data, and the image data stored in the image storage means in the order of acquisition On the other hand, the light quantity peak detecting means for reading the image data in the same order or the reverse order and detecting the light quantity peak for the region corresponding to the test site in the test object, and the light quantity peak detecting means reads the image data. Height calculating means for calculating the height of the test site from the height position of the focal plane corresponding to the light intensity peak detected after a predetermined number of the light intensity peaks detected sequentially after the start; The And butterflies.

  According to a second aspect of the present invention, in the height measuring device according to the first aspect, which number of light intensity peaks detected among the light intensity peaks detected by the light intensity peak detecting means is used? The height calculating means calculates the height of the test site from the light intensity peak based on the setting by the setting means.

  A height measuring device according to a third aspect of the present invention is the height measuring device according to the first aspect, wherein the position information of each of the plurality of test sites included in the test object is stored in the image storage means. Storage means for preliminarily storing each data of the light intensity peak designated as corresponding to each of the plurality of test sites among the light intensity peaks detected by the light intensity peak detection means and the read order data of the image data The light quantity peak detecting means detects the light quantity peak according to the reading order of the images stored in the storage means, and the height calculating means calculates the height of the test site by the light quantity peak, By performing the peak detection and the height calculation for each of the plurality of test sites, for each of the plurality of test sites stored in the storage unit Wherein the height calculation is to be carried out automatically.

  A height measuring device according to a fourth aspect of the present invention is the height measuring device according to any one of the first to third aspects, wherein an upper surface and a lower surface of a material layer made of a transparent or translucent material are inspected. It comprises a layer thickness calculating means for calculating the thickness of each material layer based on the height value after calculating the height of each part.

  According to the height measuring apparatus according to the present invention, for a test object in which a transparent or translucent material layer is formed on one material layer such as a semiconductor product, in one scanning / imaging process, It is possible to measure not only the upper surface height of the outermost layer but also the upper surface (or lower surface) height of other layers.

It is a whole lineblock diagram of the height measuring device concerning a 1st embodiment of the present invention. It is a block diagram which shows a part of signal transmission system | strain in the height measuring apparatus which concerns on the said 1st Embodiment. When scanning is performed so that the focal plane of the confocal optical system passes through the surface of the test object, the change in the amount of received light for one pixel of the image sensor corresponds to the change in the focal position of the confocal optical system. It is the graph shown. It is a side view which shows an example of the to-be-tested object whose height is measured by the height measuring apparatus which concerns on the said 1st Embodiment. It is a flowchart which shows the content (first half part) of the main routine of the execution program performed in the said height measurement apparatus. It is a flowchart which shows the content (second half part) of the main routine of the execution program performed in the said height measuring apparatus. It is a flowchart of the subroutine of height calculation in the said execution program. It is a flowchart of the subroutine of layer thickness calculation. It is a graph which shows the light quantity change with respect to the change of the focus position detected in one pixel of an image pick-up element when a height direction scan is performed by the said height measuring apparatus. It is a flowchart which shows the content (first part) of the main routine of the execution program performed in the height measuring apparatus which concerns on the modification of 1st Embodiment. It is a flowchart which shows the content (second half part) of the main routine of the execution program performed in the height measuring apparatus which concerns on the modification of 1st Embodiment. It is a side view which shows an example of the test object whose height is measured by the height measuring apparatus which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the content (first half part) of the main routine of the execution program performed in the height measuring apparatus which concerns on the said 2nd Embodiment. It is a flowchart which shows the content (second half part) of the main routine of the execution program performed in the height measuring apparatus which concerns on the said 2nd Embodiment. It is a flowchart of the subroutine of height calculation in the said execution program. It is a graph which shows the light quantity change with respect to the change of a focus position when height direction scanning is performed by the height measuring apparatus which concerns on the said 2nd Embodiment. It is a flowchart which shows the content (first part) of the main routine of the execution program performed in the height measuring apparatus which concerns on the modification of 2nd Embodiment. It is a flowchart which shows the content (second half part) of the main routine of the execution program performed in the height measuring apparatus which concerns on the modification of 2nd Embodiment.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows the overall configuration of a height measuring apparatus 1 according to the first embodiment of the present invention. As shown in FIG. 1, the height measuring apparatus 1 includes a stage 30 as an object holding unit on which an object 40 is placed, and a confocal optical system 10 installed above the stage 30. The confocal optical system 10 includes a light source 11, a collector lens 12, a half mirror 13, a pinhole disk (nipo disk) 14, a right angle mirror 15, a corner cube 16, an objective lens 17, and a connection lens. An image lens 18 and an image sensor 19 are provided. The optical axis A1 of the objective lens 17 extends in the height direction (vertical direction; z-axis direction in FIG. 1) of the test object 40, and the right angle mirror 15, the half mirror 13, the imaging lens 18 and the image sensor 19 are The pinhole disk 14 is interposed on the optical axis A1 and in the optical axis A1. The light source 11 is arranged at a position that coincides with the optical axis A1 when the optical axis A2 of the light emitted from the light source 11 is reflected by the half mirror 13, and the corner cube 16 is located on the side of the right-angle prism 15. Has been placed.

  The objective lens 17 is designed as a bi-telecentric optical system. The corner cube 16 can be moved in the left-right direction (the x-axis direction in FIG. 1) by the corner cube drive unit 26, so that the optical path length from the pinhole disk 14 to the objective lens 17 can be arbitrarily changed. It has become. The pinhole disk 14 has a large number of pinholes 14a spirally arranged at a predetermined interval, and has a rotation axis extending in parallel to the optical axis A1 (that is, extending in the z-axis direction). The disk drive unit 24 can be rotated about the vertical axis (z axis).

  The image sensor 19 is composed of a CCD camera having a large number of pixels. The image data obtained by the image sensor 19 is input to the arithmetic and control unit 31 as shown in FIGS. Further, the position of the corner cube 16 in the x-axis direction is detected by the position sensor 16 a, and the detection information is input to the arithmetic control device 31. Further, a pinhole disk drive unit 24, a corner cube drive unit 26, a storage device 32, a display device (display) 33, a keyboard 34, and a pointing device (for example, a mouse) 35 are connected to the arithmetic control device 31. In addition to outputting control signals to the disk drive unit 24 and the corner cube drive unit 26 to operate them, the image data sent from the image sensor 19 is stored (saved) in the storage device 32 and displayed on the display device 33. Can be done.

  In the confocal optical system 10 having such a configuration, the light emitted from the light source 11 such as a halogen lamp passes through the collector lens 12, is reflected downward by the half mirror 13, and is then applied to the pinhole disk 14. . The light beam that has passed through any one of the many pinholes 14 a included in the irradiation range is reflected by the upper reflecting surface of the right-angle mirror 15 and enters the corner cube 16. Then, after being reflected by the corner cube 16 and returned to the right-angle mirror 15, it is reflected downward by the lower reflective surface of the right-angle mirror 15 and enters the objective lens 17 from above. The objective lens 17 collects the light beams that have passed through the pinholes 14a and irradiates the test object 40 with them. In FIG. 1, only the optical path of the light beam that has passed through the pinhole 14a located on the optical axis A1 among the light beams that have passed through each of the many pinholes 14a is shown. Similarly, after being reflected by the right-angle mirror 15 and the corner cube 16, the light is condensed by the objective lens 17 and irradiated onto the test object 40. Each light beam collected by the objective lens 17 through these pinholes 14a has a focal point F on the same plane orthogonal to the optical axis A1 (hereinafter, a surface as a set of the focal points F is referred to as “Focus F”). Called focal plane FS).

  Light that has passed through each pinhole 14a downward and entered the test object 40 from above is reflected by the test object 40, then passes through the objective lens 17 from below, and is reflected from the lower surface of the right angle mirror 15. Reflected by. Then, after being reflected by the corner cube 16 and returned to the right-angle mirror 15, it is further reflected upward by the upper reflecting surface of the right-angle mirror 15, and enters the pinhole disk 14 from below. Here, out of the light beams reflected on the surface of the test object 40, the focus F coincides with the surface of the test object 40 (the light reflected on the intersection line between the surface of the test object 40 and the focal plane FS). Returns in the opposite direction to the same optical path as that at the time of incidence, and forms a conjugate focal point in the same pinhole 14a that has passed through when incident on the test object 40, so that the luminous flux of the pinhole remains with almost no decrease in the amount of light. Pass 14a upward. On the other hand, even if it is a light beam reflected on the surface of the test object 40, if the focal point F does not coincide with the surface of the test object 40, it does not return the same optical path as the incident light. A conjugate focal point is not formed in the same pinhole 14a that has passed through when incident on the light, and most of the amount of light is blocked by the pinhole disk 14 and lost. Therefore, among the light beams incident on the test object 40, the focal point F coincides with the surface of the test object 40 (reflected on the intersection line between the focal plane FS of the confocal optical system 10 and the surface of the test object 40). Only the light advances to the imaging lens 18 and is focused and forms an image on the imaging surface of the imaging device 19.

  Since a large number of pinholes 14a formed in the pinhole disk 14 are arranged in a spiral on the pinhole disk 14 as described above, the pinhole disk drive unit 24 is operated by the arithmetic and control unit 31 to operate the pinhole disk. When 14 is rotated, the entire surface of the test object 40 is repeatedly scanned in the radial direction centered on the optical axis A1. Further, when the corner cube driving unit 26 is operated by the arithmetic and control unit 31 to move the corner cube prism 13 in the x-axis direction, the optical path length from the pinhole 14a to the objective lens 17 continuously changes. In response to this, the FS moves in the height direction (z-axis direction) of the test object 40.

  Therefore, in this height measuring apparatus 1, if the pinhole disk 14 is rotated and the corner cube 16 is moved in the x-axis direction and an image is taken each time, the object is covered by the focal plane FS of the confocal optical system 10. An image of the cross-sectional shape of the test object 40 obtained when the test object 40 is cut (an image in which only the outline of the cross-section is brightened) is the height direction (z-axis direction) of the focal plane FS where the imaging is performed. ) Obtained in a state associated with position information. Since the height position (height direction position) of the focal plane FS corresponds to the x-axis direction position of the corner cube 16 on a one-to-one basis, the arithmetic and control unit 31 outputs the x of the corner cube 16 output from the position sensor 16a. The height position of the focal plane FS can be grasped based on the axial position information. Here, the height position of the focal plane FS is the position of the focal plane FS in the height direction with respect to the stage 30 (the height direction of the test object 40), and the focal plane FS is on the upper surface 30a of the stage 30. If the height position of the focal plane FS when matching is set to zero, the focal plane FS coincides with the test site in the test object 40 (one site in the test object whose height is to be measured). In the state, the value of the height position of the focal plane FS detected at that time is the value of the height of the region to be examined (the height from the upper surface 30a of the stage 30) as it is. Hereinafter, the height position (distance) of the focal plane FS relative to the upper surface 30a of the stage 30 is referred to as a focal plane position z.

  The amount of light received by one pixel constituting the image sensor 19 changes in the process of scanning in the height direction (z-axis direction), and the focal plane FS is located on the portion of the test object 40 that is the imaging region. In the process of approaching, the amount of received light increases, and reaches a maximum (peak) when both coincide. In the process in which the focal plane FS moves away from the site on the test object 40, the amount of received light decreases. FIG. 3 shows the relationship between the focal plane position z and the amount of received light I in the pixel. From this, when measuring the height of the test site in the test object 40, the pixel including the test site in the imaging region is designated as the specific pixel, and the predetermined value acquired in advance is specified. A scanning image (a collection of image data for each height corresponding to the cross-sectional contour shape of the test object 40) is read out for the height direction region to detect a light intensity peak, and a focal plane position z (corresponding to the light intensity peak) = Zp), the focal plane position z (= zp) becomes the height of the region to be examined as it is.

  By the way, in the present height measuring apparatus 1, the focal plane FS of the confocal optical system 10 is moved relative to the test object 40 by a certain amount (stepwise) in the height direction (z-axis direction) (stepped). When a scanning image (image data) of the test object 40 is obtained by performing imaging with the imaging device 19 at different height positions (while changing the focal plane position z in the height direction), the height position of the focal plane FS Since the data of the change in the amount of received light with respect to the change in (focal plane position z) can be obtained only as discrete data, the focal plane position z (focal plane position zp in FIG. 3) corresponding to the light quantity peak is directly detected. I can't. Therefore, in the height measuring apparatus 1, the focal plane position z corresponding to the light quantity peak is obtained by the method of sequentially comparing the light quantity of each image data of the scanned image shown below.

  First, a scanning image (image data) of the test object 40 at different height positions while moving the focal plane FS of the confocal optical system 10 relative to the test object 40 by a certain amount in the height direction. ) And each image data is stored in the storage device 32. As a result, an image data file as a set of image data is created in the storage device 32. Note that the scanning direction (movement direction) of the focal plane FS in the scanning image acquisition step may be a positive direction with respect to the z axis (a direction from bottom to top) or a negative direction with respect to the z axis (from top to bottom). Direction). Further, the storage (storing) of individual image data in the storage device 32 may be performed every time when each imaging is completed, or may be performed collectively after all the imaging in the height direction scanning region is completed. Good. Subsequently, the image data file is opened and the image data is read in a certain order. This reading order may be either the same order or the reverse order with respect to the scanning image acquisition order (the order in which the scanning image was obtained, that is, the order in which scanning in the height direction of the test object progressed).

  The arithmetic and control unit 31 opens the image data file, reads the image data, detects the light amount (luminance) for the area in the image corresponding to the test site from the read image data, and the light amount in the image data read this time And the amount of light in the previously read image data are compared. Then, from the state where the light amount of the image data read this time is larger than the light amount of the image data read last time, the light amount of the image data read this time is smaller than the light amount of the image data read last time. When switching to, it is determined that there is a light quantity peak for the area in the image during that period (detection of the light quantity peak). For example, when N is an integer, the light amount IN of the Nth image data (focal plane position is zN) and the light amount IN-1 of the N−1th image data (focal plane position is zN−1). The relationship between IN and IN-1 is the relationship between the light amount IN + 1 of the (N + 1) th image data (the focal plane position is zN + 1) and the light amount IN of the Nth image data. Then, if IN + 1 <IN, it can be seen that there is a light amount peak for the region in the image between the light amount IN + 1 and the light amount IN-1 (see FIG. 3). The in-image region corresponding to the test site is designated by the operator pre-designating a pixel including the test site in the imaging region among the many pixels constituting the image sensor 19 (described above). This is equivalent to specifying a specific pixel).

  When the value of the received light amount I with respect to the value of the focal plane position z is shown in the graph as shown in FIG. 3, it is known that the graph shape of the light amount peak has a certain known shape. Therefore, when a light amount peak is detected for a specific pixel as described above, a plurality of image data (here, three image data DN + 1 (N + 1-th image data), DN ( (Nth image data) and DN-1 (N-1th image data)) are extracted and three points (zN + 1, z) representing the relationship between the focal plane position z and the received light quantity I in these image data. IN + 1), (zN, IN), and (zN-1, IN-1) are fitted to their known shapes to obtain the focal plane position zp (see FIG. 3) corresponding to the light quantity peak for the specific pixel. be able to. When the focal plane position zp is obtained, the height of the test site (the upper surface of the test object 40 in FIG. 3) can be known.

  By the way, the above description is an example in which the test object 40 is made of a single material and only the upper surface (surface) of the test object 40 is the only test site for a specific pixel. However, in the case of an object having a two-layer structure in which a transparent or semi-transparent material layer (upper layer) is formed on the upper surface side of one material layer (lower layer), in addition to the upper surface of the upper layer, the lower layer The upper surface can also be a test site for a specific pixel. In such a case, in addition to the light reflected on the upper surface of the upper layer, the light intensity peak is also observed for the light reflected on the upper surface of the lower layer (also the lower surface of the upper layer) (see FIG. 9). However, in the conventional height measuring apparatus, the scanning image reading order is performed only in the scanning image acquisition order (the order in which the scanning image is obtained, that is, the order in which the scanning of the test object 40 proceeds in the height direction). In addition, after the light intensity peak is detected by the above-described light intensity comparison, the light intensity comparison is not performed after that, so only one height measurement can be performed in one height direction scan. . As will be described later, the height measuring apparatus 1 also has a configuration in which the light intensity comparison is not performed after the light intensity peak is detected. Since the test can be started from either the forward order or the reverse order, even if the test object 40 has the above-described two-layer structure, scanning image acquisition by the height direction scan is performed only once. Both the upper surface height of the upper layer and the upper surface height of the lower layer can be obtained.

  Next, a specific procedure for measuring the height of the test site in the test object 40 by the height calculation apparatus 1 will be described with reference to FIGS. Here, as shown in FIG. 4, a test object 40 having a two-layer structure of a lower layer 41 made of a non-transparent material and an upper layer 42 made of a transparent (or translucent) material formed on the upper surface 41 a of the lower layer 41. The example which measures the height of each upper surface (41a, 42a) of both layers 41 and 42 of this will be shown. Note that the scanning direction (moving direction) of the focal plane FS in the scanning image acquisition step is a positive direction (a direction from bottom to top) with respect to the z axis. The starting point of the height direction scanning region is an arbitrary position (focal plane position z = zs) lower than the upper surface 41a of the lower layer 41, and the end point is an arbitrary position higher than the upper surface 42a of the upper layer 42 (focal plane position z = ze). (See FIG. 4).

  5 to 8 are flowcharts showing the contents of the execution program stored in the storage device 32. The arithmetic and control unit 31 loads the execution program from the storage device 32 into an internal memory (not shown) and executes it. 5 and 6 are main routines of the execution program, and the circled characters shown in both drawings indicate that the flow continues in the same character portion. First, as shown in FIG. 5, the arithmetic and control unit 31 operates the corner cube driving unit 26 to make the focal point F of the confocal optical system 10 coincide with the start point of the height direction scanning region (step S <b> 1). The pinhole disk drive unit 24 is operated to start rotation of the pinhole disk 14 (step S2). As a result, an image corresponding to the current focal plane position z = zs (the start point of the height direction scanning region) (an image in which only the outer diameter shape of the lower layer 41 is bright) is displayed on the image sensor 19. Note that the rotational speed of the pinhole disk 14 can be arbitrarily set by the operator by a separate input operation.

  When the pinhole disk 14 starts rotating, the arithmetic and control unit 31 then operates the corner cube drive unit 26 to move the focal point F of the confocal optical system 10 by a certain amount Δz in the height direction (z-axis direction) ( (Step S3). As a result, an image corresponding to the current focal plane position z = zs + Δz is displayed on the image sensor 19, so that the arithmetic and control unit 31 captures the image with the image sensor 19 (step S4) and then obtains the obtained image data. Is stored in the storage device 32 (step S5). After storing the image data, the arithmetic and control unit 31 determines whether or not the height direction scanning is finished, and whether or not the current focal plane position z coincides with the end point (z = ze) of the height direction scanning region. Judgment is made based on whether or not (step S6). When it is determined that the height direction scanning has not ended, the processes of steps S3 to S5 are repeated, and when it is determined in step S6 that the height direction scanning has ended, the loop is exited. At the time of exiting this loop, the storage device 32 has a total of M image data having numbers n = 1, 2,..., M (M is an integer) in order from the start side of the height direction scanning. An image data file is created (step S7).

  When the image data file is created in step S7, the operator designates, as a specific pixel, a pixel that includes the height measurement target part (test part) in the imaging region from among a large number of pixels constituting the image sensor 19 (step S7). S8). The specific pixel is specified by calling one of the image data stored in the storage device 32 and displaying the image data on the display device 33, and then the operator sees the image data in a partial position on the test object 40. This is performed by designating the region indicated as “test region” in FIG. When the test area is designated by the operator, the arithmetic and control unit 31 extracts and stores the pixel located at the center of the test area as a specific pixel.

  When the specific pixel is designated in step S8, the operator subsequently sets the scanning image reading order (reading order when reading the image data from the image data file) (step S9). This input is performed from the keyboard 34. The scanning image readout order is set to either the same order or the reverse order with respect to the scanning image acquisition order. Here, it is assumed that the order is set in the same order (in the order of image data numbers 1 → 2 →... → M). After setting the scanning image reading order, the operator further selects from the keyboard 34 whether to calculate not only the height but also the layer thickness (here, the layer thickness of the upper layer 42). (Step S10).

  When the operator designates specific pixels, sets the scanning image readout order, and selects whether or not to perform layer thickness calculation, the arithmetic and control unit 31 proceeds to step S11 to enter the height calculation subroutine shown in FIG. enter. In the height calculation subroutine, first, the image data file stored in the storage device 32 is opened (step S21), and then scanning image reading is started in the order set by the operator in step S9 (step S22). Then, peak detection is performed as described above. That is, the scanning images are sequentially read out to compare the light amount for the specific pixel, and this light amount comparison is repeated until a light amount peak is detected (step S23). When the light quantity peak (light quantity peak P1 shown in FIG. 9) is detected in this way, scanning image reading is terminated (step S24), and a plurality of image data (the above-mentioned three image data DN + described above) constituting the detected light quantity peak. (Image data corresponding to 1, DN, DN-1) is extracted, and the image data file is closed (step S26). As described above, the three points (zN + 1, IN + 1), (zN, IN), (zN-1, IN-1) indicating the relationship between the focal plane position z and the light quantity I in the plurality of image data. ) To the known shape, the focal plane position zp corresponding to the light intensity peak for the specific pixel is obtained (step S27), and the region to be examined (the upper surface 41a specific pixel of the lower layer 41 is determined from this focal plane position zp). The height of the corresponding part is calculated (step S28), and the process returns to the main routine. In this height calculation, the refractive index data of the material of the upper layer 42 that transmits the light from the light source 11 is referred to (this refractive index data may be stored in the storage device 32 in advance). The measurement error due to the influence of the refractive index is corrected.

  After calculating the height of the region to be examined (the portion corresponding to the specific pixel on the upper surface 41a of the lower layer 41) in step S28, the arithmetic and control unit 31 returns to the main routine and sends the calculated height value to the display unit 33. After the display (step S12), it is determined whether or not the operator has selected to calculate the layer thickness in step S10 (step S13). If the operator has not selected to calculate the layer thickness, the operator is subsequently prompted to determine whether or not he / she intends to end the height measurement by the height measuring device 1 (step S14). ). If the operator selects the end of measurement (the selection is performed from the keyboard 34), the arithmetic and control unit 31 ends the execution program. On the other hand, when the operator selects measurement continuation (non-end) in step S14 (the selection is performed from the keyboard 34), the process returns to step S8, so that the operator can perform a new test site (different specific pixel). The height measurement or the height measurement of the upper surface 42a of the upper layer 42 can be performed for the same specific pixel by changing the readout order (the layer thickness calculation is selected for the height measurement of the upper surface 42a of the upper layer 42). Automatically as described below). Since the image data file has already been created and stored in the storage device 32, it is not necessary to perform the scanning image acquisition process (steps S1 to S7) again.

  On the other hand, if the operator has selected to calculate the layer thickness in step S10, the process proceeds from step S13 to step S15, and the test site calculated in step S11 (corresponding to the specific pixel on the upper surface 41a of the lower layer 41). (Part) height data is stored in the storage device 32 (step S15), and it is determined whether or not the height measurement necessary for calculating the layer thickness has already been completed (step S16). Here, since the height of the upper surface 42a of the upper layer 42 has not yet been obtained and the measurement necessary for calculating the layer thickness has not been completed, the process proceeds to step S17, and the reading order of the scanned image is changed (step S9). In step S11, the height is calculated again.

  In this process, the arithmetic and control unit 31 reads the image data in the order of number M → (M−1) →... And detects the light quantity peak P2 shown in FIG. 9, and the focal plane position corresponding to the light quantity peak P2. From z, the height of the upper surface 42a of the upper layer 42 is calculated. In step S12 that returns to the main routine, the height value is displayed on the display device 33. Then, the process proceeds to step S13, and the test site (specification on the upper surface 42a of the upper layer 42) calculated in the second step S11 is performed. The height data of the portion corresponding to the pixel is stored in the storage device 32 (step S15), and it is determined whether or not the height measurement necessary for calculating the layer thickness has already been completed (step S16). Here, since the height of the upper surface 42a of the upper layer 42 has already been obtained and the measurement necessary for calculating the layer thickness has been completed, the process proceeds to the next step S18 and the two heights stored in the storage device 32 are obtained. The height data file is created by combining the height data (height data of the upper surface 41a of the lower layer 41 and height data of the upper surface 42a of the upper layer 42).

  When the height data file is created in step S18, the process proceeds to step S19 to enter the layer thickness calculation subroutine shown in FIG. In the layer thickness calculation subroutine, first, the height data file created in step S18 is opened (step S31), and the height data stored (saved) is read (step S32). When all the height data (here, the height data of the upper surface 41a of the lower layer 41 and the height data of the upper surface 42a of the upper layer 42) are read, the difference between them is calculated and the layer thickness of the upper layer 42 (in the specific pixel) The layer thickness of the upper layer 42 of the corresponding part is obtained by calculation (step S33). When the layer thickness of the upper layer 42 is obtained by calculation, the height data file is closed (step S34), and the process returns to the main routine to display the value of the layer thickness of the upper layer 42 on the display device 33 (step S20). When the value of the layer thickness of the upper layer 42 is displayed in step S20, the process proceeds to step S14 to prompt the operator to determine whether or not to finish the height measurement by the height measuring apparatus 1. Here, when the operator selects the end of measurement, the arithmetic and control unit 31 ends the execution program. On the other hand, when the operator selects the measurement continuation (non-end) in step S14, the process returns to step S8 as described above, so that the operator can measure the height of a new test site.

  As described above, in the height measuring apparatus 1 according to the first embodiment of the present invention, the test is performed from the height position (focal plane position z) of the focal plane FS corresponding to the light quantity peak detected first after the scanning image reading is started. Based on a conventional height measuring device having a configuration for calculating the height of the part, and further, the reading order of the scanned image can be set to either the same order or the reverse order with respect to the acquiring order of the scanned image. Yes. For this reason, although it is the structure which calculates the height of a to-be-tested part based on the focal plane position z corresponding to the light quantity peak detected first after the reading start of a scanning image, it is one like a semiconductor product etc. For the test object 40 in which a transparent or semi-transparent material layer is formed on the material layer, if only the upper surface height (the height of the upper surface 42a of the upper layer 42) is obtained in one scanning / imaging process, It is also possible to measure the upper surface height of other layers (the height of the upper surface 41a of the lower layer 41). The layer thickness of the transparent material layer (upper layer 42) formed on the upper surface 41a of the lower layer 41 can also be measured.

  By the way, the height measuring apparatus 1 according to the above embodiment calculates the height of the test site corresponding to a certain pixel (specific pixel) designated by the operator. Whether to perform pixel designation in step S8, designation of reading order in step S9, and calculation of layer thickness in step S10. It is troublesome for the operator to manually input each of these selections, and the time required is enormous. The following example is a modification of the first embodiment, and is an automated series of processes including the above input.

  10 to 11 are flowcharts of the execution program in the modification of the first embodiment. The arithmetic and control unit 31 loads the execution program from the storage device 32 into an internal memory (not shown) and executes it. The circled characters shown in FIGS. 10 and 11 indicate that the flow continues in the same character portion. Also, the height calculation subroutine (step S11) and the layer thickness calculation subroutine (step S19) in this flow are the same as those shown in the above-described embodiment.

  In the execution program according to the modification of the first embodiment, a process corresponding to step S1 of the first embodiment described above (a process of setting the focal point of the confocal optical system at the operation start position) is automatically started. That is, after starting the rotation of the pinhole disk (step S2), the arithmetic and control unit 31 reads a movement command from the storage device 32 (step S2.1) and shares the test object 40 according to the read movement command. The focal point optical system 10 is moved to the start point of the scanning area scanned in the XYZ (three-dimensional) direction (step S2.2). The movement of the focal point F of the confocal optical system 10 is specifically performed by the arithmetic control device 31 operating the corner cube driving unit 26.

  After moving to the start point of the scanning area of the confocal optical system 10 in step S2.2, imaging is performed while moving the focal point of the confocal optical system 10 by a certain amount in the height direction as in the case of the first embodiment described above. The obtained image data is stored in the storage device 32 to create an image data file (steps S3 to S7). Thus, when the image data file is created, the arithmetic and control unit 31 opens the measurement condition file stored in the storage unit 32 (step S7.1). In this measurement condition file, the position of each of a plurality of test sites included in the test object 40, the reading order of images stored in the storage device 32, and each data on whether or not to calculate the layer thickness for each pixel are stored. It is remembered. Specifically, the position data of the test site included in the measurement condition file is stored as position data in the entire image of the pixels corresponding to the plurality of test sites whose heights are to be obtained. The pixels for which the height is to be calculated may be a part or all of the pixels constituting the captured image data. Further, the position of the test site may be determined while viewing the image acquired by the operator after the image data file is created in step S7. As a determination method, for example, a method of setting an area using a keyboard, a pointing device, or the like while viewing an image of the test object 40 displayed on the display can be considered.

  The image reading order data included in the measurement condition file refers to the scanning image reading order set in step S9 (reading order setting step) of the first embodiment described above (when image data is read from the image data file). Is the same or reverse order of the scanned image acquisition order. The designation of the reading order may be designated collectively as common to all the pixels for calculating the height, or may be arbitrarily designated for each pixel.

  After opening the measurement condition file in step S7.1, the arithmetic and control unit 31 first reads data at the position of the specific pixel (step S8). This process corresponds to step S8 in the first embodiment described above, and sequentially picks up a plurality of pixels written in the measurement condition file (to be subjected to height calculation) and corresponds to the pixels. In this step, the pixel position data stored in the memory is read. For example, pixel position data to be measured is read from CAD data (design drawing data). When the data at the position of the specific pixel is read in step S8, the reading order designation data written in the measurement condition file is read (step S9). This process corresponds to step S9 in the first embodiment described above.

  When the reading order designation data is read in step S9, the layer thickness calculation designation written in the measurement condition file is read (step S10). This process corresponds to step S10 in the first embodiment described above. When step S10 is completed, the arithmetic and control unit 31 proceeds to step S11 and enters a height calculation subroutine (see FIG. 7). In addition to the height calculation process in this subroutine, the subsequent height result output, height data file creation, layer thickness calculation process for layer thickness calculation, and layer thickness result output process Since (Step S11 to Step S20) is exactly the same as that shown in the first embodiment, the description thereof is omitted. In step S14 in this series of steps, in the first embodiment, the operator inputs whether or not the operator intends to end the height measurement by the height measuring device 1, but in the first embodiment. In the modified example, when the height calculation has not been performed for all the pixels for which the height calculation is to be performed, and the pixel for which the height calculation is to be performed still remains, the process returns to step S8 and the height calculation is performed. When no power pixel remains, that is, when the height calculation is completed for all the pixels for which the height calculation is to be performed, the loop is exited. When the loop is exited, the measurement condition file is closed (step S20.1), and the execution program is terminated.

  As described above, in the height measuring device according to the modification of the first embodiment, if the operator sets in advance data related to a plurality of test sites to be calculated in height, all the test sites are thereafter set. Since the height calculation is automatically performed, it is possible to work efficiently even if there are a wide or many test sites for which the height calculation is desired.

  Next, a height measuring apparatus according to the second embodiment of the present invention will be described with reference to FIGS. The height measurement device according to the second embodiment is different from the height measurement device 1 according to the first embodiment described above only in the execution program related to height measurement. In the height measuring apparatus 1 according to the first embodiment described above, when a light intensity peak is detected by light intensity comparison, the subsequent light intensity comparison is not performed, and the object corresponding to the light intensity peak detected first after the start of scanning image scanning is started. Although it was an execution program that can only determine the height of the inspection site, in the height measurement device according to the second embodiment, the operator designated as an effective peak among the light intensity peaks that are sequentially detected after the start of scanning image scanning. By continuing the light amount comparison while ignoring other than the light amount peak, only the light amount peak designated as the effective peak can be extracted, and the height of the test site corresponding to this can be obtained. For this reason, as in the case of the first embodiment described above, the scanning image acquisition step by the height direction scanning is performed only once, and the upper surface height of each layer of the two-layer structure test object can be measured. As for the test object having a structure of three or more layers in which a plurality of transparent or semi-transparent layers are formed on the upper surface side, the height of the upper surface of each layer can be obtained by one image data acquisition.

  Hereinafter, a specific procedure for measuring the height of the test site by the height calculation apparatus according to the second embodiment will be described. Here, as shown in FIG. 12, a lower layer 141 made of a non-transparent material, an intermediate layer 142 made of a translucent material formed on the upper surface 141a of the lower layer 141 (but laminated on a part of the lower layer 141), and a lower layer 141 Alternatively, the upper surface (141a, 142a, 143a) of each of the layers 141, 142, 143 of the test object 140 having a two-layer or three-layer structure with the upper layer 143 made of a transparent material formed on the upper surface 142a of the intermediate layer 142. An example of measuring the height is shown. In this case as well, the scanning direction (movement direction) of the focal plane FS in the scanning image acquisition step is the positive direction (the direction from bottom to top) with respect to the z axis. Further, it is assumed that the scanning image readout order is set in the same order as the acquisition order. Further, the start point of the height direction scanning region is an arbitrary position (focal plane position z = zs) lower than the upper surface 141a of the lower layer 141, and the end point is an arbitrary position higher than the upper surface 143a of the upper layer 143 (focal plane position z = ze). (See FIG. 12).

  FIGS. 13 to 15 (and FIG. 8 described above) are flowcharts showing the contents of the execution program stored in the storage device 32. FIGS. 13 and 14 are main routines of the execution program. Circled characters shown in both drawings indicate that the flow continues in the same character portion. The arithmetic and control unit 31 first creates an image data file for the height direction scanning region in the steps S41 to S47, but the procedure is the same as steps S1 to S7 in the first embodiment. The description is omitted here.

  When the image data file is created in step S47, the operator selects a pixel that includes the height measurement target part (test part) in the test area (FIG. 12) from among a large number of pixels constituting the image sensor 19. (Step S48). Note that this specific pixel designation method is the same as in the first embodiment.

  When the specific pixel is designated in step S48, the operator subsequently selects from the keyboard 34 whether to calculate not only the height but also the layer thicknesses of the intermediate layer 142 and the upper layer 143 (step S49). Further, among the light intensity peaks that are sequentially detected after the scanning image reading is started, those corresponding to the region to be examined are selected and designated as effective peaks (step S50). This designation is performed by inputting from the keyboard 34 the number of the light quantity peak that is detected after the effective peak is read out of the scanned image. For example, as in this example, when the scanning direction (movement direction) of the focal plane FS in the scanning image acquisition step is the positive direction with respect to the z axis, and the reading order of the scanning images is the same as the acquisition order, As shown in FIG. 16, for the region B having a three-layer structure (the regions A and C are two-layer structures), the light intensity peak corresponding to the upper surface of the lower layer 141 (or the lower surface of the intermediate layer 142) 141a is read out of the scanned image. The first light quantity peak P1 detected after the start and the light quantity peak corresponding to the upper surface (or the lower surface of the upper layer 143) 142a of the intermediate layer 142 are the second light quantity peak P2 and the upper layer 143 detected after the start of scanning image scanning. The light amount peak corresponding to the upper surface 143a is the light amount peak P3 detected third after the start of scanning image scanning. Here, it is assumed that the light amount peak corresponding to the upper surface 142a of the intermediate layer 142 in the region B having the three-layer structure (that is, the light amount peak P2 detected second after the scanning image is read) is set as an effective peak.

  When the operator designates a specific pixel, selects whether or not to perform layer thickness calculation, and designates an effective peak, the arithmetic and control unit 31 proceeds to step S51 and enters the height calculation subroutine shown in FIG. In the height calculation subroutine, first, the image data file stored in the storage device 32 is opened (step S61), and the scanned images are read in a predetermined order (as described above, here in the same order as the scanned image acquisition order). Reading is started (step S62). Then, peak detection is performed in the same manner as in the first embodiment. That is, the scanning images are sequentially read out to compare the light amount for the specific pixel, and the light amount comparison is repeated until the light amount peak is detected (step S63). However, here, the light amount comparison is not ended when the light amount peak is detected, but whether or not the light amount peak detected at that time is the effective peak designated in step S50 (here, the detected light amount). It is determined whether the peak is the second light intensity peak after the start of reading (step S64). If the detected light intensity peak is not an effective peak, the process returns to step S63 to continue the light intensity comparison, and the detected light intensity peak. When is a valid peak, the light quantity comparison is terminated.

  As a result, when a light intensity peak corresponding to the effective peak designated in step S50 is detected, reading of the scanned image is terminated (step S65), and a plurality of light intensity peaks (here, the light intensity peak P2 shown in FIG. 16) constituting the detected light intensity peak. Image data (image data corresponding to the above-mentioned three image data DN + 1, DN, DN-1) is extracted and the image data file is closed (step S66). Thereafter, the process proceeds from step S66 → S67 → S68 → S69 to calculate the height of the region to be examined (here, the portion corresponding to the specific pixel on the upper surface 142a of the intermediate layer 142). Since it is the same as that of the embodiment (steps S25 to S28 in the description of the first embodiment), the description thereof is omitted here.

  After calculating the height of the region to be examined in step S69, the arithmetic and control unit 31 returns to the main routine and displays the calculated height value on the display device 33 (step S52). It is determined whether or not the selection for calculating the thickness has been made (step S53). If the operator has not selected to calculate the layer thickness, the operator is subsequently prompted to determine whether or not he / she intends to end the height measurement by the height measuring device (step S54). . If the operator selects the end of measurement (the selection is performed from the keyboard 34), the arithmetic and control unit 31 ends the execution program. On the other hand, when the operator selects measurement continuation (non-end) in step S54 (the selection is made from the keyboard 34), the process returns to step S48, so that the operator can measure the height of a new test site. . Since the image data file has already been created and stored in the storage device 32, the scanning image acquisition process (steps S1 to S7) needs to be performed again when measuring the height of a new test site. It is the same as in the first embodiment.

On the other hand, if the operator has designated to calculate the layer thickness in step S49, the process proceeds from step S53 to step S55, and the test site calculated in step S51 (corresponding to the specific pixel on the upper surface 142a of the intermediate layer 142). Is stored in the storage device 32 (step S55), and the operator is prompted to determine whether or not the height measurement necessary for calculating the layer thickness has already been completed (step S56). Here, when it is desired to obtain the layer thickness of the upper layer 143, only the height of the upper surface 142a of the intermediate layer 142 is currently measured, and the layer thickness (here, the layer thickness of the upper layer 143) is measured. Since the measurement required for the calculation is not completed, a message to that effect is input from the keyboard 34. As a result, the process returns to step S50, and this time, the light amount peak corresponding to the upper surface 143a of the upper layer 143 is designated as an effective peak. When the next effective peak is designated, the arithmetic and control unit 31 again enters step S51 and calculates the height. In this process, the arithmetic and control unit 31 detects the light quantity peak P3 shown in FIG. 16, and calculates the height of the upper surface 143a of the upper layer 143 corresponding to the light quantity peak P3. After returning to the main routine, in step S52, the height value is displayed on the display device 33. Then, the process proceeds to step S53, where the test site calculated in the second step S51 (specification on the upper surface 143a of the upper layer 143 is specified). The height data of the portion corresponding to the pixel is stored in the storage device 32 (step S55), and the operator is prompted to determine whether or not the height measurement necessary for calculating the layer thickness has already been completed (step S56). ). Here, the height of the upper surface 143a of the upper layer 143 has already been obtained, and the measurement necessary for calculating the layer thickness (layer thickness of the upper layer 143) has been completed. Accordingly, the process proceeds to the next step S57, and the two height data (the height data of the upper surface 142a of the intermediate layer 142 and the height data of the upper surface 143a of the upper layer 143) stored in the storage device 32 are collectively collected. Create

  When the height data file is created in step S57, the process proceeds to step S58 to enter the layer thickness calculation subroutine shown in FIG. The program content of the subroutine for calculating the layer thickness is the same as in the first embodiment. First, the height data file created in step S57 is opened (step S31), and the height data stored (saved) here. Is read (step S32). When all the height data (here, the height data of the upper surface 142a of the intermediate layer 142 and the height data of the upper surface 143a of the upper layer 143) are read, the difference is calculated and the layer thickness of the upper layer 143 is calculated. Obtained (step S33). When the layer thickness of the upper layer 143 is obtained by calculation, the height data file is closed (step S34), and the process returns to the main routine to display the value of the layer thickness of the upper layer 143 on the display device 33 (step S59). When the value of the layer thickness of the upper layer 143 is displayed in step S59, the process proceeds to step S54 to prompt the operator to determine whether or not to finish the height measurement by the height measuring apparatus. Here, when the operator selects the end, the arithmetic and control unit 31 ends the execution program. On the other hand, when the operator selects measurement continuation (non-end) in step S54, the process returns to step S48 as described above, so that the operator can measure the height of a new test site.

  As described above, in the height measuring apparatus according to the second embodiment of the present invention, it is possible to designate, as an effective peak, a light intensity peak that is sequentially detected after the scanning image reading is started and that corresponds to the test site. After the start of scanning image scanning, the light intensity peak until the specified effective peak is ignored, and the light intensity comparison is continued to extract only the light intensity peak specified as the effective peak. Thus, the height of the test site corresponding to this can be obtained. For this reason, as in the case of the height measuring apparatus 1 according to the first embodiment, once for a test object in which a transparent or translucent material layer is formed on one material layer, such as a semiconductor product. In the scanning / imaging step, not only the top surface height (the height of the top surface 143a of the upper layer 143) but also the top surface heights of the other layers (the height of the top surface 141a of the lower layer 141 and the intermediate layer 142). It is possible to measure the height of the upper surface 142a (that is, the height of the region to be examined corresponding to the light intensity peak detected after a predetermined time after the start of scanning image reading).

  The following modified example of the second embodiment includes designation of a pixel corresponding to step S48 in the second embodiment, selection of whether or not to perform layer thickness calculation corresponding to step S49, and an effective peak corresponding to step S50. This is an example of a case where a series of processing including each designated input is automated.

  FIGS. 17 to 18 are flowcharts of the execution program in the modification of the second embodiment. The arithmetic and control unit 31 loads the execution program from the storage device 32 into an internal memory (not shown) and executes it. The circled characters shown in FIGS. 17 and 18 indicate that the flow continues in the same character portion. The height calculation subroutine (step S51) and the layer thickness calculation subroutine (step S58) in this flow are the same as those shown in the second embodiment.

  In the execution program according to the modification of the second embodiment, a process corresponding to step S41 of the second embodiment described above (a process of setting the focus of the confocal optical system at the operation start position) is automatically started. That is, after starting the rotation of the pinhole disk (step S42), the arithmetic and control unit 31 reads the movement command from the storage device 32 (step S42.1), and the test object 140 is read according to the read movement command. The confocal optical system 10 is moved to the start point in a scanning region (that is, a region to be examined including regions A, B, and C in FIG. 16) that scans in the XYZ (three-dimensional) direction (step S42.2).

  After moving to the start point of the scanning area of the confocal optical system 10 in step S42.2, as in the case of the second embodiment described above, imaging is performed while moving the focal point of the confocal optical system 10 by a certain amount in the height direction. The obtained image data is stored in the storage device 32 and an image data file is created (steps S43 to S47). When the image data file is created in this way, the arithmetic and control unit 31 then opens the measurement condition file stored in the storage device 32 (step S47.1). This measurement condition file includes the positions of a plurality of test sites included in the test object 40, the reading order of images stored in the storage device 32, whether or not to perform layer thickness calculation for each pixel, and designation of effective peaks Each data is stored. Here, the position data of the test site, the data of the reading order of the image, and the contents of the data for specifying the layer thickness calculation included in the measurement condition file are the same as in the modification of the first embodiment. The effective peak designation data is the light quantity peak designation data designated in step S50 in the second embodiment, that is, the light quantity peak detected after the start of scanning image reading as corresponding to the region to be examined. This is data that is specified by the operator in advance.

  After opening the measurement condition file in step S47.1, the arithmetic and control unit 31 first reads the position data of the specific pixel (data of each measurement scanning position in the areas A, B, and C in FIG. 16) (step S48). This process corresponds to step S48 in the second embodiment described above, and corresponds to a plurality of pixels (areas A, B, and C that are about to be calculated in height) written in the measurement condition file. Pixel) is picked up in order, and the pixel position data stored corresponding to the areas A, B, and C is read. When the position data of the specific pixel is read in step S48, the reading order designation data for each of the areas A, B, and C described in the measurement condition file is read (step S48.1), and the layer thickness calculation designation is read. (Step S49) and reading of effective peak designation (Step S50) are performed.

  When step S50 is completed, the arithmetic and control unit 31 proceeds to step S51 and enters a height calculation subroutine (see FIG. 15). In addition to the height calculation process in this subroutine, the subsequent height result output, height data file creation, layer thickness calculation process for layer thickness calculation, and layer thickness result output process The contents of (Step S51 to Step S59) are the same as those shown in the second embodiment. In step S54 in this series of steps, in the second embodiment, the operator inputs whether or not the operator intends to end the height measurement by the height measuring device. In the modified example, when the height calculation has not been performed for all the pixels for which the height calculation is to be performed and there are still pixels for which the height calculation is to be performed, the process returns to step S48 and the height calculation should be performed. When no pixels remain, that is, when the height calculation for all the pixels for which the height calculation is to be completed is completed, the loop is exited and the measurement condition file is closed (step S59.1). When step S59.1 ends, the arithmetic control device 31 ends the execution program.

  As described above, in the height measuring apparatus according to the modification of the second embodiment, data relating to a plurality of test sites (regions A, B, and C in FIG. 16) to be calculated in advance by the operator is set in advance. After that, since the height calculation for all the test sites is automatically performed, even if there are wide or many test sites for which the height calculation is desired, the work can be efficiently advanced. Is possible.

  The preferred embodiments of the present invention have been described so far, but the scope of the present invention is not limited to those shown in the above-described embodiments. For example, in the first embodiment described above, the scanning direction (moving direction) of the focal plane FS in the scanning image acquisition process is the positive direction (the direction from bottom to top) with respect to the z axis. It may be a negative direction with respect to the axis (a direction from top to bottom). In addition, the test object 40 in the first embodiment has a two-layer structure, but this is not limited as long as it is configured by forming a transparent or translucent material layer on one material layer. It may be a layer. However, as can be seen from the above explanation, only the thickness of the uppermost surface of the lowermost layer and the uppermost surface of the uppermost layer and the thickness of the entire transparent / translucent material layer formed on the upper surface of the lowermost layer can be measured. .

  In the second embodiment described above, the example of measuring the height of the upper surface 142a of the intermediate layer 142 and the height of the upper surface 143a of the upper layer 143 has been described. However, the height of the upper surface 141a of the lower layer 141 is determined by the same procedure. Can also be measured. In the above-described embodiment, the example in which the layer thickness of the upper layer 143 that is the transparent material layer is obtained has been described. However, the layer thickness of the intermediate layer 142 that is the semitransparent material layer can be obtained by the same procedure. It is. In the above-described embodiment, the scanning direction (movement direction) of the focal plane FS in the scanning image acquisition process is the positive direction with respect to the z-axis, but this may be a negative direction with respect to the z-axis. Further, although the scanning image reading order is the same as the acquisition order, it may be reverse to the acquisition order. Further, the scanning image reading order may be arbitrarily selected by the operator as in the first embodiment. In addition, the test object 140 has a three-layer structure, but this is an example, and how many layers are formed by forming a transparent or translucent material layer on one material layer. It is possible to measure the top surface height of all layers and the layer thickness of each layer of the transparent or translucent material layer.

  In the first embodiment, the specific pixel is specified in step S8 of FIG. 5 and the height calculation and the layer thickness calculation are performed on the specified pixel. However, in step S8, the specific pixel is specified. Without specifying, the height may be calculated for all the pixels (when the thickness is selected in step S10, the layer thickness is also calculated). And after calculating with respect to all the pixels, you may designate a specific pixel and may output the calculation result in the specific pixel. The same applies to the specific pixel designation in step S48 of FIG. 13 in the second embodiment, and the specific pixel may be designated after calculating the layer height for all the pixels.

  Further, as a form different from the above-described embodiment, the arithmetic and control unit 31 uses the scanning images acquired in the scanning image acquisition process (scanning / imaging process) in a certain order (scanning direction of the focal plane FS in the scanning image acquisition process). Read out in the same order or in reverse order) and once all the light intensity peaks are detected, this is displayed on the display device 33 or the like in the form of a graph as shown in FIG. 9 or FIG. Then, when the operator selects one corresponding to the test site whose height is to be obtained from the displayed light intensity peak, the image data before and after the selected light intensity peak is picked up and the light intensity comparison is performed. The focal plane position z corresponding to the light quantity peak can be calculated to obtain the height of the region to be examined.

  In the above-described embodiment, the height of the focal plane FS with respect to the test object 40 (the height of the test object 40 is changed by moving the corner cube 16 in the x-axis direction to change the optical path length of the measurement light. Direction) Relative movement was performed, but without moving the confocal optical system 10, the stage 30 on which the test objects 40 and 140 are placed is moved in the height direction of the test object 40. You may make it perform the relative movement of the focal plane FS with respect to the test object 40 in the height direction.

  In the height measuring apparatus shown in the above-described embodiment, a so-called multi-beam confocal optical system having a focal plane FS formed as a set of focal points F is used. However, the height measurement according to the present invention is used. The apparatus can also use a single beam confocal optical system that forms only a single focal point. However, when such a single beam type confocal optical system is used, it is formed when the focal point is scanned in the direction perpendicular to the height direction of the test object (in the xy plane in the above-described embodiment). The focal locus plane to be formed corresponds to a focal plane (focal plane FS in the above-described embodiment) formed when a multi-beam confocal optical system is used.

DESCRIPTION OF SYMBOLS 1 Height measuring apparatus 10 Confocal optical system 11 Light source 17 Objective lens 19 Image sensor 26 Corner cube drive part (image acquisition means)
30 stage 31 arithmetic control device (image acquisition means, light intensity peak detection means, height calculation means, layer thickness calculation means)
32 Storage device (image storage means, storage means)
34 Keyboard (reading order setting means, setting means)
40 Object A1 Optical axis of confocal optical system FS Focal plane of confocal optical system

Claims (4)

Confocal optics,
Image acquisition means for acquiring image data of the test object at different height positions while relatively moving the focal plane of the confocal optical system in the height direction with respect to the test object;
Image storage means for storing the image data;
A light intensity peak for reading out the image data stored in the image storage means in the same order or in reverse order with respect to the acquisition order and detecting a light intensity peak in a region corresponding to the test site in the test object Detection means;
The light intensity peak detection means detects the height of the region to be examined from the height position of the focal plane corresponding to the light intensity peak detected after a predetermined number of the light intensity peaks sequentially detected after the start of reading of the image data. A height measuring device comprising: a height calculating means for calculating. Setting means for setting which number of light intensity peaks detected among the light intensity peaks detected by the light intensity peak detection means, the height calculation means is based on the setting in the setting means; The height measurement apparatus according to claim 1, wherein the height of the test site is calculated from the light intensity peak. Of the position information of each of the plurality of test sites included in the test object, the data in the reading order of the image data stored in the image storage means, and the light quantity peak detected by the light quantity peak detection means A storage means for storing in advance each data of the light intensity peak designated as corresponding to each of a plurality of test sites,
The light quantity peak detection means detects the light quantity peak according to the reading order of the images stored in the storage means,
The height calculation means calculates the height of the test site from the light intensity peak, and the peak detection and the height calculation are performed for each of the plurality of test sites, whereby the storage unit stores the height. 2. The height measuring apparatus according to claim 1, wherein height calculation for each of a plurality of test sites is performed automatically. After calculating the respective heights using the upper and lower surfaces of a material layer made of a transparent or translucent material as the test site, the layer thickness for calculating the layer thickness of the material layer based on these height values The height measuring apparatus according to claim 1, further comprising a calculating unit.

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