JP4696599B2 - Measuring device with confocal optical system - Google Patents

Description

  The present invention relates to a measuring apparatus that measures a test site 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 measuring the height of the region to be examined, all scanned image data at a predetermined interval on each Z-axis is captured. As the height is measured with higher accuracy, the scanning image capturing interval in the Z-axis direction is narrowed, and the amount of scanned image data becomes enormous. As a result, there is a problem that the memory for image data mounted on the measuring apparatus becomes large-scale, and arithmetic processing such as height measurement and shape measurement is slowed accordingly.

  The present invention has been made in view of such problems, and provides a measuring apparatus having a confocal optical system capable of suppressing the storage capacity of image data of a test object and speeding up data processing such as shape measurement. The purpose is that.

In order to achieve such an object, the measuring apparatus of the present invention includes a confocal optical system, and moves the focal plane of the confocal optical system relative to the test object in the height direction while different height positions. Each time, image data of the test object is sequentially acquired, the image data is compared with each part of the test object, and desired image data is extracted and stored. The shape of the test object can be measured based on the data.

According to the measuring apparatus according to the present invention, only the minimum necessary image data of the test object is stored without storing all the image data for each focal plane position of the test object. Data processing such as shape measurement can be speeded up.

(Overall configuration of measuring apparatus 1)
Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a configuration diagram of a confocal optical system of a height measuring apparatus 1 according to an embodiment of the present invention. FIG. 2 shows a block diagram of the control system of the measuring apparatus 1.

  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, that is, the z-axis direction in FIG. 1) of the test object 40. 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 test object 40 is, for example, a semiconductor IC package in this embodiment. 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. The position of the corner cube 16 in the x-axis direction is detected by the position sensor 16a, and the detection information is input to the arithmetic control device 31 (microprocessor). The arithmetic control unit 31 includes a pinhole disk drive unit 24, a corner cube drive unit 26, a storage device 32 (semiconductor memory, a removable memory, etc.), a display device (liquid crystal display) 33, a keyboard 34, and a pointing device (for example, Mouse) 35 is connected, and control signals are output to the pinhole disk drive unit 24 and the corner cube drive unit 26 to operate them, and the image data sent from the image sensor 19 is stored in the storage device 32. (Stored) and can be displayed on the display device 33.

  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, the plane as a set of the focal points F is referred to as a 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, among the light beams reflected on the surface of the test object 40, the light flux reflected at the intersection line between the surface of the test object 40 and the focal plane FS, the focus F of which coincides with the surface of the test object 40, That is, the optical image (confocal image) of the test site at the confocal position of the test object 40 formed by the confocal optical system returns to the test object 40 in the opposite direction along the same optical path as that at the time of incidence. Since the conjugate focal point is formed in the same pinhole 14a that has passed when the light beam is incident, the luminous flux passes through the pinhole 14a with almost no decrease in the amount of light. On the other hand, even if it is a light beam reflected on the surface of the test object 40, the one whose focal point F is not coincident with the surface of the test object 40 (non-confocal image) does not return the same optical path as that at the time of incidence. Therefore, a conjugate focal point is not formed in the same pinhole 14a that has passed when entering the test object 40, 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 16 in the x-axis direction, the optical path length from the pinhole 14a to the objective lens 17 continuously changes, so that the focal plane FS. Accordingly, the test object 40 moves in the height direction (z-axis direction).

  Therefore, in this height measuring apparatus 1, if the pinhole disk 14 is rotated and the corner cube 16 is moved every predetermined step (every interval) in the x-axis direction, an image is taken each time. An image of a cross-sectional shape of the test object 40 obtained when the test object 40 is cut by the focal plane FS of the focus optical system 10 (an image in which only the outline of the cross-section is bright, that is, a confocal image of the test object 40) ) Is obtained in a state associated with information on the position in the height direction (z-axis direction) of the focal plane FS where the image is taken. 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.

In the above description, the relative movement between the test object 40 and the confocal optical system 10 is realized by moving the corner cube 16 in the x-axis direction. However, the present invention is not limited to this, and the stage 30 is moved in the Z-axis direction. Alternatively, the corner cube 16 and the stage 30 may be moved relative to each other.

(Description of the structure of the test object 40 for measuring the shape and height)
The structure of the test object 40 (here, IC chip) according to the present embodiment will be described. FIG. 3 is a cross-sectional view of an IC package that is the test object 40. FIG. 4 shows an example of the height measurement of a part of the wire 144 of the IC package, where the vertical axis shows the displacement in the Z-axis direction and the horizontal axis shows the change in the received light quantity I.

  As shown in FIGS. 3 and 4, the test object 40 that is an IC chip covers the substrate 141 made of a non-transparent material, the semiconductor chip 142 placed on the upper surface 141 a of the substrate 141, and the semiconductor chip 142. And a protective resin 143 made of a non-transparent material. A plurality of wires 144 for conducting the substrate 141 and the semiconductor chip 142 are connected to the plurality of electrodes 141 b on the substrate and the plurality of electrodes 142 a on the semiconductor chip 142. The plurality of wires 144 are protected by a protective resin 143.

  Here, an example in which the present measuring apparatus is used for determining a defect of an IC chip will be described. For example, in the case of a normal IC chip, all the wires 144 are covered with the protective resin 143 by the protective resin 143. However, if the wire bonder is defective, the wires 144 jump out of the protective resin 143. Sometimes. In order to determine whether or not such a wire 144 exists, high-speed measurement by this measuring apparatus is necessary. For this purpose, the maximum height of each wire 141 connected to the semiconductor chip 142 and the substrate 141 may be measured to determine whether or not each maximum height is within the height of the protective resin 143.

  The test object 40 which is an IC chip shows an example in which a plurality of wires 144 exist and the height of each wire 144 is measured at the maximum height. For convenience of explanation, FIG. 4 shows an example of measuring the height of a part of the wire 144, the vertical axis indicates the displacement in the Z-axis direction of the focal plane, and the horizontal axis indicates the longitudinal position of the wire 144 and the received light amount I. Shows changes.

  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 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 substrate 141, and the end point is an arbitrary position higher than the upper surface 143a of the protective resin 143 (focal plane position z = ze).

  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 (brightness level) increases and reaches a maximum (light amount peak) when they match. 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. 4 shows the relationship between the focal plane position (scanning direction) z and the amount of received light I in the pixel. From this, when measuring the height of the test site of the wire 144 in the test object 40, for example, pay attention to the three pixels (A, B, C) including the test site in the imaging region. To explain, the scanning image (collection of image data for each height corresponding to the cross-sectional contour shape of the test object 40) in the height direction region is read out with a predetermined height direction resolution (z1 to z15) and the amount of light. If the peak (I12, I22, I32) is detected and the focal plane position (z4, z8, z12) corresponding to the light intensity peak is obtained, the focal plane position z (= zi) becomes the height of the region to be examined as it is. .

In order to measure the height with higher accuracy, an interpolation calculation process may be used as described below. In the present height measuring apparatus 1, the focal plane FS of the confocal optical system 10 has a predetermined resolution in the height direction (z-axis direction) with respect to the test object 40 (predetermined steps zi, i = 1 to 15). While relatively moving (changing the focal plane position z in the height direction), the imaging device 19 performs imaging at different height positions. Therefore, when the image sensor 19 acquires a scanned image (image data) of the test object 40, the received light amount change data with respect to the change in the height position of the focal plane FS (focal plane position zi) is assumed to be discrete. Therefore, the focal plane position z below the resolution corresponding to the light quantity peak cannot be directly detected. Therefore, in order to obtain the focal plane position (Zpi, i = 1 to 3) of the light quantity peak, the focal plane positions before and after the light quantity peak (for example, in the case of the pixel A, z3, z4 and z5) are used to determine the focal plane position below a predetermined resolution.

(Description of the shape measurement process of the test object)
Hereinafter, a specific procedure for measuring the shape of the test object 40, which is an IC package, by the height measuring apparatus according to the present embodiment will be described with reference to FIGS. FIG. 5 shows a conceptual diagram of the shape measuring process (image processing) of the measuring apparatus. FIG. 6 is a flowchart of the shape measurement process (image process) of the measurement apparatus.

  As shown in FIG. 5, the characteristic configuration of the shape measurement process includes a peak detection unit 31a, a three-dimensional (3D) image construction unit 31b, an integration processing unit 31c, and an error processing unit 31d. The received scanned image data is in acquisition and storage. The scanned image data here refers to image data in units of pixels of the imaging device 19 (two-dimensional CCD element). That is, the imaging device 19 stores scanned image data while moving the focal plane of the confocal optical system in the z-axis direction at predetermined resolutions (predetermined intervals) in order to acquire a three-dimensional image of the test object 40. However, the storage device 32 does not store all of the scanned image data sent from the imaging device 19. Unnecessary scanned image data (image data in units of pixels) is removed by the peak detector 31a of the arithmetic and control unit 31 interposed between the imaging device 19 and the storage device 32, and the contour of the test object 40 is stored in the storage device 32. Only image data corresponding to an image (xyz coordinate information and luminance level information corresponding to image data having a peak value of the luminance level) and defective pixel information are stored. The principle is that only the optical image (confocal image) of the test site at the confocal position of the test object 40 formed by the confocal optical system is extracted from the image data of the imaging device 19. is there. Only the image data corresponding to the confocal image is stored in the storage device 32 (32a to 32d) as the image data associated with the xyz coordinate information.

  The imaging device 19 sequentially examines the object at different height positions (predetermined resolution in the z-axis direction) while moving the focal plane of the confocal optical system 10 relative to the object 40 in the height direction. 40 pieces of image data are acquired for each pixel of the imaging device 19, and the image data acquired at different height positions are sequentially output to the peak detector 31a.

  The peak detection unit 31a compares the luminance levels of the pixel unit image data acquired for each height position, and finally extracts image data indicating the peak value of the luminance level in each pixel (for the champion data). Extraction). At that time, when the height position is obtained with higher accuracy than the resolution for each height position, the image data indicating the peak value and the image data before and after the peak value are extracted for the interpolation processing calculation. The image data for each unit pixel includes luminance level information (Ik-1, Ik, Ik + 1) and xyz coordinate information (Zk-1, Zk, Zk + 1), and is stored in the image data storage unit 32d. Remembered. The xyz coordinate information is sent to the three-dimensional (3D) image construction unit 31b, and the luminance level information is sent to the integration processing unit 31c.

  The three-dimensional (3D) image construction unit 31b obtains the height of each part of the test object based on the xyz coordinate information (Zk-1, Zk, Zk + 1) of the image data indicating the peak value at each pixel. The height data of each part of the test object is output and stored in the 3D image storage unit 32b. This 3D image is displayed on the display device 33 by, for example, pseudo color information based on the height data of the test object 40. Thereby, when the monitor of the display device 33 is viewed, the height of each test part of the test object 40 can be identified by the color.

  Based on the luminance level information (Ik-1, Ik, Ik + 1) of the image data at different heights, the integration processing unit 31c generates an integrated image (synthesized image) by integrating them. This integrated image data is obtained by integrating the luminance level information of the image data indicating the peak value of the test object 40 and the luminance level information of the image data before and after that (based on the reflected light from the test object 40). Image data). The accumulated image data is output to and stored in the accumulated image storage unit 32c.

  The error processing unit 31d specifies a defective pixel from the image data for each pixel acquired by the imaging device 19. By monitoring the luminance level information of the image data acquired for each pixel, for example, the luminance level is compared with a predetermined upper limit or lower limit luminance level, and from the appropriate luminance range of the upper limit or lower limit luminance level. A deviating pixel can be identified as a defective pixel. As a result, the address information corresponding to the defective pixel on the imaging surface of the imaging device 19 is output to and stored in the error image storage unit 32d.

The data stored in the storage device 32 can be transferred to an external device such as a PC through a transfer path such as Ethernet (registered trademark).

Next, the processing procedure of the arithmetic and control unit 31 of this measuring apparatus will be described with reference to FIG.

  FIG. 6 is a flowchart showing the contents of an execution program stored in the storage device 32. The arithmetic and control unit 31 loads the execution program from an execution program storage device (not shown) into an internal memory (not shown) and executes it.

  When measuring the shape of the test object 40 of the IC chip, the wire 144 of the test object 40 before being filled with the protective resin 143 is measured. For example, by measuring the maximum height of each of a large number of wires 144 formed on the IC chip, it is possible to inspect whether or not there is a defect in which each wire 144 jumps out when the protective resin 143 is filled. . Therefore, the shape measurement of the wire 144 will be specifically described below.

  Steps 1 and 2: First, as shown in FIG. 6, the arithmetic and control unit 31 operates the corner cube driving unit 26 to set the focal point F of the confocal optical system 10 to the start point of the height direction scanning region (z1 in FIG. 4). ) (Step S1), the pinhole disk drive unit 24 is operated to start rotation of the pinhole disk 14 (step S2). As a result, an image (image of the surface 141a of the substrate 141) corresponding to the current focal plane position zi = z1 (starting point of the height direction scanning region) is displayed on the display device 33 on the imaging device 19.

  Step 3: The arithmetic and control unit 31 acquires the scanned image data (luminance level information and xyz coordinate information) at the focal plane position zi from the image sensor 19 and temporarily stores it in the image data file. This image data file stores a predetermined number of pieces of image data, and luminance data information and xyz coordinate information are stored for each pixel unit as each image data.

This image data is sequentially sent to the peak detection processing unit 31a (step 4) and the error processing unit 31d.
The error processing unit 31d identifies a defective pixel from the image data that has been sequentially sent as already described. The address data of the identified defective pixel is stored in the error image storage unit 32d.

  Step 4: The peak detection process is executed. The arithmetic and control unit 31 opens the image data file and sequentially reads the image data. From the read image data, the brightness level information about the area in the image corresponding to the test site of the test object 40 is detected, and the brightness level information in the image data read this time and the brightness level information in the image data read last time, Compare Then, from the state in which the brightness level information of the image data read this time is larger than the brightness level information of the image data read last time, the brightness level information of the image data read this time is higher than that of the image data read last time. When switching to a state where the brightness level information is smaller than that, it is determined that a light amount peak for the region in the image exists during that time (detection of the light amount peak). For example, if N is an integer, the luminance level information IN of the Nth image data (focal plane position is zN) and the luminance level information IN-1 of the N−1th image data (focal plane position is z> N-1), where IN> IN-1, the luminance level information IN + 1 of the (N + 1) th image data (focal plane position is assumed to be zN + 1) and the Nth image data In the case of IN + 1 <IN in relation to the luminance level information IN, there is a light amount peak for the region in the image between the luminance level information IN + 1 and the luminance level information IN-1. I understand that.

  For example, the peak value I12 is detected based on the luminance level distribution IA at the portion A of the test site A of the wire 144 in FIG. Similarly, the peak values I32 and I22 are detected based on the luminance level distributions IB and IC at the test sites B and C on the wire 144. When interpolation processing is performed to perform this peak detection, luminance level information of image data before and after the image data indicating the peak value (I11 and I13 are detected in the pixel A corresponding to the point A, and the point B is detected. I11 and I13 are detected in the pixel B corresponding to, and I21 and I23 are detected in the pixel C corresponding to the point C).

  Step 5: 3D image construction processing is executed. The xyz coordinate data related to the image data having the light intensity peak detected in step 4 (luminance levels I12, I22, I32 in FIG. 4) is acquired. In FIG. 4, at point A of the wire 144, xyz coordinate information (z3 to z5) related to the luminance level information (I11 to I13) is acquired. At point B, xyz coordinate information (z11 to z13) related to the luminance level information (I31 to I33) is acquired. At point C, xyz coordinate information (z7 to z9) related to the luminance level information (I21 to I23) is acquired. Based on the xyz coordinate information, the shape of the wire 144 is three-dimensionally constructed from the height information (z information) of the wire 144. For example, the three-dimensional image of the wire 144 is constructed by color by pseudo-coloring the height information. Alternatively, a three-dimensional image of the wire 144 is constructed with brightness and darkness by displaying the height information in brightness.

Then, only the xyz coordinate information of the image data having the light amount peak of the wire 144 is stored in the 3D image storage unit 32 b of the storage device 32.
That is, when focusing attention on the pixel of the imaging device 19 corresponding to the point A portion of the wire 144 shown in FIG. 4, there are 15 pieces of image data Z1 to Z15 as the point A image data. . However, in the apparatus of the present embodiment, not all 15 image data of the pixels of the imaging device 19 corresponding to the part of the point A are stored in the storage device 32, and only 3 image data of Z3 to Z5 are stored. Will be. Thus, in this embodiment, the storage capacity of image data can be suppressed, and the shape measurement process of the wire 144 can be executed at high speed. Since the same processing as described above is performed in relation to each pixel of the imaging device 19, the storage capacity of the image data can be significantly reduced.

  Step 6: Perform integrated image processing. Only brightness level information is acquired from the image data having the light intensity peak detected in step 4. In FIG. 4, luminance level information (I11 to I13) is acquired at point A of the wire 144. At point B, the luminance level information (I31 to I33) is acquired. At point C, luminance level information (I21 to I23) is acquired. An integrated image of point A of the wire 144 is created by integrating the luminance level information (I11 to I13). Similarly, the points B and C are created by integrating three pieces of luminance level information. As a result, the wire 144 is shaped according to the brightness information.

Only the luminance level information of the image data having the light intensity peak of the wire 144 is stored in the integrated image storage unit 32 c of the storage device 32. Other image data is not stored.
That is, when focusing attention on the pixel of the imaging device 19 corresponding to the point A portion of the wire 144 shown in FIG. 4, there are 15 pieces of image data Z1 to Z15 as the point A image data. . However, in the apparatus of the present embodiment, not all 15 image data of the pixels of the imaging device 19 corresponding to the part of the point A are stored in the storage device 32, and only 3 image data of Z3 to Z5 are stored. Will be. Thus, in this embodiment, the storage capacity of image data can be suppressed, and the shape measurement process of the wire 144 can be executed at high speed. Since the same processing as described above is performed in relation to each pixel of the imaging device 19, the storage capacity of the image data can be significantly reduced.

  Step 7: Move the focal plane position of the confocal optical system by a fixed amount zi (i = 1 to 15) in the Z-axis direction. For every fixed amount of movement, image data having a light amount peak is searched as in step 4 described above.

  Step 8: Steps 3 to 7 are repeated until the focal plane position of the confocal optical system is scanned in the Z-axis direction (until z15 is reached). Thereby, the image data of the test object 40 can be efficiently acquired, the storage capacity of the storage device 32 can be suppressed, and the shape measurement of the test object 40 can be speeded up.

  Step 9: In the image display routine of the test object 40, a 3D image and an integrated image of the test object 40 can be displayed on the monitor screen of the display device 33. At that time, the user can select whether or not to read out defective pixel data using the keyboard 34. The user can read error information from the address data of the defective pixel and display that the image data obtained from the defective pixel has low reliability. For example, by attaching a specific color to the image data corresponding to the defective pixel, it can be identified as a normal pixel on the monitor display. Thus, if a defective pixel can be specified, the reliability of the height calculation result can be obtained as information at the same time.

  In the height calculation subroutine, first, xyz coordinate data stored in the 3D image storage unit 32b of the storage device 32 is read, and the height of the desired part of the test object 40 is calculated from the z-axis information, that is, the height information. To do. Specifically, the height measurement from the bottom of the test object 40 is performed by pointing the height measurement location of the test object 40 desired by the operator on the display device 33.

Next, if the operator has selected to perform layer thickness calculation (level difference calculation), the thickness of the detected part of the test object is calculated from the XYZ coordinate data, as in the height measurement.

It is a figure which shows the confocal optical system of the shape measuring apparatus which concerns on embodiment of this invention. It is a block diagram of the shape measuring apparatus which concerns on the said 1st Embodiment. It is a side view which shows IC package which is an example of a test object. An example of measuring the height of a part of the wire 144 of the IC package is shown, with the vertical axis representing the displacement in the Z-axis direction and the horizontal axis representing the change in the amount of received light I. The conceptual diagram of the shape measurement process (image processing) of a measuring device is shown. The flowchart figure of the shape measurement process (image process) of a measuring device is shown.

Explanation of symbols

1 Height measuring device
10 Confocal optical system
11 Light source
17 Objective lens
19 Image sensor
26 Corner cube drive
30 stages
31 arithmetic control unit
32 storage devices
34 Keyboard
40 specimen
A1 Optical axis of confocal optical system
Focal plane of FS confocal optical system

Claims (8)

Confocal optics,
A pinhole disk disposed in the optical path of the light that illuminates the test object and having a plurality of pinholes;
Image data of the test object is sequentially obtained for each different height position while relatively moving the focal plane of the confocal optical system in the height direction with respect to the test object by the light passing through the pinhole. Image acquisition means for acquiring;
Image data comparing means for comparing the image data acquired by the relative movement for each part of the test object and extracting the image data in which the light intensity reaches a peak ;
The image data storage means for storing the image data obtained by the image data comparison means and the image data before and after the peak, and for storing the focal plane position of the stored image data;
A height calculation unit that reads a focal plane position of the image data from the image data storage unit, and calculates a height of the test site by interpolation processing based on the focal plane position ;
A measuring apparatus having a confocal optical system. The measurement apparatus having the confocal optical system according to claim 1,
A measurement apparatus having a confocal optical system, further comprising: a three-dimensional image construction unit that constructs a three-dimensional image from the image data stored in the image data storage unit. The measurement apparatus having the confocal optical system according to claim 2 ,
Said image data storage means, the image data obtained initially and temporarily stores the image acquisition means, said image said extracted by the data comparing means image data of said replaced with primary stored image data stored ,
The measuring apparatus having a confocal optical system, wherein the three-dimensional image constructing unit constructs the three-dimensional image from the replaced image data. A measuring apparatus having the confocal optical system according to any one of claims 1 to 3 ,
The measurement apparatus having a confocal optical system, wherein the image data storage means stores focal plane position information at the time of acquisition of the stored image data. A measuring apparatus having the confocal optical system according to any one of claims 1 to 4 ,
The image acquisition means is a two-dimensional image sensor having a plurality of pixels,
The measuring apparatus having a confocal optical system, wherein the image data comparing means compares image data for each pixel. In the measurement apparatus having the confocal optical system according to any one of claims 2 to 5 ,
A measuring apparatus having a confocal optical system, further comprising display means for displaying the three-dimensional image. A measuring apparatus having the confocal optical system according to any one of claims 1 to 6 ,
A defective pixel detection means for detecting a pixel defect of the image acquisition means based on the image data acquired by the image acquisition means;
Storage means for storing address information of defective pixels detected by the defective pixel detection means;
A measuring apparatus having a confocal optical system. The measuring apparatus having the confocal optical system according to claim 7 ,
The measurement apparatus having a confocal optical system, wherein the image generation means includes selection means capable of selecting whether or not to perform image generation using image data of the defective pixel

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