JP2004020202A - Method and apparatus for measuring dimension of infinitesimal shape section - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance mass productivity by facilitating automation at a measuring time and to enhance measuring efficiency at the time of production by shortening the measuring time. <P>SOLUTION: When a height H of an infinitesimal shape section Ws of an article W to be measured is measured by an optical interference method, a preliminary measuring section 2 for detecting the position including at least the height direction of the infinitesimal shape section Ws, and a main measuring section 3 for measuring the height H of the infinitesimal shape section Ws by the optical interference method are set to a predetermined positional relation. At the measuring time, the infinitesimal shape section Ws is detected by the preliminary measuring section 2, positioning of the infinitesimal shape section Ws is performed, and thereafter the main measuring section 3 is moved by a set distance Ls based on a predetermined positional relation, the main measuring section 3 is positioned at a reference position Ps, and thereby the height of the infinitesimal shape section Ws is measured. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus suitable for measuring the size of a minute shape portion, which are suitable for measuring the height of a minute shape portion in an object to be measured by an optical interference method.
[0002]
[Prior art]
Conventionally, a method (apparatus) for measuring the shape of a minute shape portion in an object to be measured by an optical interference method is disclosed in JP-A-8-502828, JP-A-9-503065, and JP-A-10-62139. In addition, as a method (apparatus) for measuring the height of a minute shape portion, a height measuring method and apparatus disclosed in Japanese Patent Application Laid-Open No. 8-327327 are known.
[0003]
In the shape measurement (height measurement method) using the light interference method (white light interference method), first, a white light source having a short coherence distance is irradiated from a white light source onto a half mirror in a two-beam interference optical system, and a reference light is emitted. And the measurement light, and the reference light and the measurement light interfere with each other to generate interference fringes. At this time, if the distance between the measurement optical path and the reference optical path matches, the luminance of the interference fringe becomes maximum, so that the distance of the measurement optical path is relatively changed with respect to the reference optical path, and the generated interference fringes are imaged. The three-dimensional shape (the height of the Z-axis) of the object to be measured is measured by obtaining the maximum optical path difference by image processing.
[0004]
[Problems to be solved by the invention]
By the way, in a color filter used for a liquid crystal display, a spacer projection is integrally formed on a substrate because of the necessity of providing a minute gap. The spacer projections are usually formed to have a height of about 5 μm, are provided at intervals of about several hundred μm, and the height of the spacer projections must be kept within a certain tolerance. Therefore, the height is measured in the inspection process to check whether the height is within the tolerance.
[0005]
However, when such a spacer protrusion is inspected on a production line, it is not easy to find a reference position at which measurement is started by optical interferometry with a conventional height measuring method and apparatus using optical interferometry. , Usually relying on moving them to an estimated position. For this reason, the accuracy of finding the correct position is small, and eventually the measurement takes a long time, resulting in a decrease in measurement efficiency, and it is not easy to establish automation at the time of measurement, resulting in poor mass productivity. there were.
[0006]
The present invention solves the problems existing in such conventional techniques, and facilitates automation at the time of measurement to increase mass productivity, and shortens measurement time to increase measurement efficiency at the time of production. It is an object of the present invention to provide a method and an apparatus for measuring a dimension of a minute shape portion that can be formed.
[0007]
Means and Embodiments for Solving the Problems
The dimension measuring method of the minute shape portion according to the present invention detects a position including at least the height direction of the minute shape portion Ws when measuring the height H of the minute shape portion Ws in the workpiece W by an optical interference method. The preliminary measurement unit 2 and the main measurement unit 3 that measures the height H of the minute shape portion Ws by the optical interference method are set in a fixed positional relationship, and the small shape portion Ws is detected by the preliminary measurement unit 2 during measurement. The positioning of the minute shape portion Ws is performed, and thereafter, the main measurement portion 3 is moved by a set distance Ls based on a fixed positional relationship, and the main measurement portion 3 is positioned at the reference position Ps. The height measurement is performed.
[0008]
In this case, according to a preferred embodiment, a spacer protrusion Wss integrally formed on the substrate B for providing a minute gap can be applied to the minute shape portion Ws, and the light interference method uses a white light interference method. Can be. In addition, the preliminary measurement unit 2 can perform a focusing process by measuring at least a distance from above to the minute shape portion Ws.
[0009]
On the other hand, the dimension measuring device 1 for the minute shape portion Ws according to the present invention uses the preliminary measurement unit 2 for detecting a position including at least the height direction of the minute shape portion Ws and the height H of the minute shape portion Ws by an optical interference method. The detection of the minute shape portion Ws by the preliminary measurement portion 2 and the measurement mechanism portion Fs in which the main measurement portion 3 to be measured is set in a fixed positional relationship performs positioning with respect to the minute shape portion Ws, and sets the main measurement portion 3 to a fixed position. It is characterized by comprising a measurement unit M having a movement mechanism unit Fm that is moved to a reference position Ps for measuring the height of the minute shape part Ws by moving by a set distance Ls based on the positional relationship.
[0010]
In this case, the preliminary measurement unit 2 can be configured to include the distance measurement sensor 11 that measures a distance from at least the top of the minute shape portion Ws and performs a focusing process. The dimension measuring device 1 includes a transport mechanism 4 that sequentially transports a plurality of objects W to be measured and stops at a predetermined measurement position, and measures the transport in a direction perpendicular to the transport direction T of the transport mechanism 4. A plurality of units M can be arranged.
[0011]
【Example】
Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.
[0012]
First, the configuration of the dimension measuring apparatus 1 according to the present embodiment will be described with reference to FIGS. Note that the DUT W in the example is a substrate B of a color filter used in a liquid crystal display, and the minute shape portion Ws is a projection Wss for a spacer integrally formed on the substrate B. The dimension measuring apparatus 1 (dimension measuring method) according to the present embodiment can expect particularly good results (effect) when applied to such a spacer projection Wss.
[0013]
As shown in FIG. 1, the dimension measuring apparatus 1 includes a measuring unit M having a measuring mechanism Fs and a moving mechanism Fm. In addition, the measurement mechanism unit Fs includes a preliminary measurement unit 2 and a main measurement unit 3, and the preliminary measurement unit 2 and the main measurement unit 3 are integrated via a coupling member 51 so as to have a fixed positional relationship therebetween. .
[0014]
The preliminary measurement unit 2 has a function of detecting a position including at least the height direction of the minute shape portion Ws. The preliminary measurement unit 2 according to the embodiment detects the positions in the X-axis direction, the Y-axis direction, and the Z-axis direction with respect to the minute shape portion Ws. The positions in the X-axis direction and the Y-axis direction are imaged from above by the CCD camera 10 provided in the preliminary measurement unit 2 and detected as coordinate points by image processing. As for the position in the Z-axis direction, the distance from the upper portion to the minute shape portion Ws is measured by the distance measuring sensor 11. In this case, in the Z-axis direction, when measuring the position, the measurement unit M is displaced in the Z-axis direction using the moving mechanism unit Fm, and the positioning in the height direction is performed simultaneously by performing a focusing process. The setting of the setting position (X-axis direction position) of the workpiece W in the transport mechanism unit 4 described later and the setting of the transport amount (Y-axis direction position) with respect to the workpiece W can be performed by the preliminary measurement unit 2. Position detection (positioning) in the X-axis direction and the Y-axis direction can be eliminated. The CCD camera 10 used in the preliminary measurement section 2 can also be used as a CCD camera in an image processing and inspection process for detecting a defect such as a scratch on the measured object W or adhesion of a foreign substance.
[0015]
On the other hand, the main measurement section 3 has a function of measuring the height H of the minute shape portion Ws by an optical interference method. The main measuring unit 3 of the embodiment uses a Mirau interferometer, and as shown in FIG. 1, a white light source 12 using a halogen lamp and a half mirror inclined at 45 ° with respect to the horizontal. 13, an illumination lens 14 arranged on the lateral side of the half mirror 13, an optical fiber 15 for allowing white light from the white light source 12 to enter the illumination lens 14 in a horizontal direction, and An imaging lens 16 disposed, an objective lens 17 disposed below the half mirror 13, a half mirror 18 disposed horizontally below the objective lens 17, and a micromirror disposed between the half mirror 18 and the objective lens 17. 19, a piezo actuator 20 for varying a measurement optical path (measurement distance), and a CCD camera 21 disposed above the imaging lens 16.
[0016]
On the other hand, the movement mechanism unit Fm performs positioning with respect to the minute shape portion Ws by detecting the minute shape portion Ws by the preliminary measurement unit 2, and moves the main measurement unit 3 by a set distance Ls based on a fixed positional relationship. It has a function of positioning at the reference position Ps for measuring the height of the minute shape portion Ws. That is, the moving mechanism unit Fm includes an X-axis direction moving mechanism unit 25 that moves the measuring mechanism unit Fs in the X-axis direction, a Z-axis direction moving mechanism unit 26 that moves the X-axis direction moving mechanism unit 25 in the Z direction. And a Y-axis moving mechanism 27 for moving the Z-axis moving mechanism 26 in the Y-direction, thereby moving the measuring mechanism Fs in the X-, Y-, and Z-axis directions. Can be.
[0017]
Further, a controller 31 having a built-in computer processing function executes sequence control, data processing, and the like for the dimension measuring method according to the present embodiment. The controller 31 relates to the measurement mechanism unit Fs, and outputs signals obtained from the position control unit 32 that controls the piezo actuator 20, the light source control unit 33 that controls the white light source 12, the preliminary measurement unit 2, and the CCD camera 21. A signal processing unit 34 for processing (image processing) is provided, and an X-axis driver unit 35 for driving and controlling the X-axis direction moving mechanism unit 25 and a Z-axis direction moving mechanism unit 26 are associated with the moving mechanism unit Fm. A Z-axis driver section 36 for controlling the driving and a Y-axis driver section 37 for controlling the driving of the Y-axis direction moving mechanism section 27 are provided.
[0018]
Further, the controller 31 includes a display (monitor) for monitoring the measurement state. 4 and 5 show examples of the display screen on the display. FIG. 4 is a display screen V1 mainly showing measurement data and a determination result of the measurement data, and an image data display section showing the X-axis and Y-axis directions of the minute shape portion Ws in XY coordinates. 5, an image data display section 42 for displaying the position of the minute shape portion Ws in the X-axis direction and the Z-axis direction by XZ coordinates, a numerical data display section 43 for displaying various numerical data, and the like. The screen V2 has a three-dimensional display unit 44 that three-dimensionally displays the minute shape part Ws (spacer projection Wss).
[0019]
The measuring unit M having such a measuring mechanism unit Fs and a moving mechanism unit Fm is attached to a transport mechanism unit 4 constituting a production line, as shown in FIG. In this case, the transport mechanism unit 4 has a function of sequentially transporting a plurality of objects to be measured W arranged in two horizontal rows and stopping at a predetermined measurement position. In addition, a plurality of (four in the embodiment) measurement units M are prepared, and the measurement units M are arranged and arranged in a direction perpendicular to the transport direction T of the transport mechanism unit 4. By arranging a plurality of measurement units M in this way, it is possible to contribute to further improvement in mass productivity and measurement efficiency.
[0020]
Next, the operation (function) of the dimension measuring apparatus 1 including the dimension measuring method according to the present embodiment will be described with reference to FIGS. 1 to 5 and 7 and the flowchart shown in FIG.
[0021]
First, by controlling the transport mechanism 4, the workpieces W are transported in the transport direction indicated by the arrow T (step S1). Then, the conveyance is stopped at the preset measurement position (steps S2 and S3). In this case, the measurement mechanism unit Fs is set to the position shown in FIG. 7 by the X-axis direction movement mechanism unit 25, that is, the detection position Pd at which the preliminary measurement unit 2 detects the minute shape part Ws. Then, a detection process is performed on the minute shape portion Ws (step S4). Note that the detection processing includes not only the detection but also the positioning processing of the measurement mechanism unit Fs with respect to the minute shape part Ws based on the detection result.
[0022]
In the detection processing, the object to be measured W is imaged from above by the CCD camera 10 in the preliminary measurement unit 2, and the position of the minute shape part Ws in the X-axis direction and the Y-axis direction is detected as a coordinate point by image processing. When the positions in the X-axis direction and the Y-axis direction are detected, the X-axis driver unit 35 and the Y-axis driver unit 37 drive and control the X-axis direction moving mechanism unit 25 and the Y-axis direction moving mechanism unit 27, respectively, to perform preliminary measurement. The detection center of the distance measuring sensor 11 in the section 2 is displaced so as to be at the upper end of the minute shape section Ws, and the Z-axis driver section 36 controls the driving of the Z-axis direction moving mechanism section 26 to move the preliminary measurement section 2 in the Z-axis direction. Focusing processing is performed by displacing in the direction. In addition, by setting the setting position (X-axis direction position) of the workpiece W in the transport mechanism unit 4 and setting the transport amount (Y-axis direction position) with respect to the workpiece W, the X Position detection (positioning) in the axial direction and the Y-axis direction becomes unnecessary.
[0023]
When the detection process by the preliminary measurement unit 2 is completed, the X-axis driver unit 35 controls the driving of the X-axis direction movement mechanism unit 25 to move the measurement mechanism unit Fs by the set distance Ls (steps S5 and S6). As a result, the main measurement unit 3 is displaced to the reference position Ps for measuring the height H of the minute shape part Ws. In this case, since the preliminary measurement unit 2 and the main measurement unit 3 are set according to a fixed positional relationship, the set distance Ls is set based on this fixed positional relationship, that is, the detection distance of the preliminary measurement unit 2 and the main distance. The distance between the measurement centers of the measurement unit 3 is set as the set distance Ls.
[0024]
As described above, if the positioning in the X-axis direction and the Y-axis direction including at least the height direction (Z-axis direction) with respect to the measurement mechanism unit Fs is performed using the preliminary measurement unit 2, the measurement is performed by the X-axis direction movement mechanism unit 25. By simply moving the mechanism section Fs by the set distance Ls, the main measurement section 3 can be easily and surely set to the reference position Ps for measuring the height of the minute shape section Ws.
[0025]
When the main measurement unit 3 is set at the reference position Ps, a measurement process for measuring the height of the minute shape part Ws by the main measurement unit 3 is executed (step S7). At the time of measurement, white light from the white light source 12 enters the objective lens 17 via the optical fiber 15, the illumination lens 14, and the half mirror 13. While the white light is focused by the objective lens 17, half of the light quantity is reflected by the half mirror 18 and enters the micro mirror 19, and the other half of the light quantity passes through the half mirror 18 and exits downward. The light reflected by the minute shape portion Ws and the light reflected by the minute mirror 19 return to the half mirror 18 again, where interference fringes are generated. The brightness of the interference fringes is maximized when the distance from the half mirror 18 to the minute mirror 19 and the optical path length of the light reflected on the minute shape portion Ws match. At this time, since the phases match irrespective of the wavelength of the light, interference fringes with the highest brightness occur, and on the other hand, the phase difference increases with each wavelength of light by moving away from the point of coincidence. Brightness (interference intensity) decreases rapidly.
[0026]
Therefore, if the objective lens 17 is continuously moved in the optical axis direction while focusing on the reference position Ps, the intensity curve K of the interference fringe shown in FIG. 3 is obtained. That is, since the interference fringes are imaged on the CCD camera 21 by the imaging lens 16, the controller 31 controls the piezo actuator 20 and intermittently moves the objective lens 17 by a very small amount in the optical axis direction to capture an image. For example, the interference fringe luminance data is stored in the memory of the controller 31, and an intensity curve K shown in FIG. 3 sampled at regular intervals is obtained. Therefore, if the interference center point is obtained from the sampled data and is captured two-dimensionally, the height H of the minute shape portion Ws can be measured with high accuracy.
[0027]
Such processing can be independently performed in parallel for each of the measurement units M shown in FIG. Each of the objects to be measured W is sequentially transported by the transport mechanism unit 4, and the same measurement process is repeatedly performed (steps S8 and S9). Therefore, according to the dimension measuring method (dimension measuring device 1) of the minute shape portion Ws, it is possible to accurately and quickly perform the positioning of the main measurement portion 3 with respect to the minute shape portion Ws using the preliminary measurement portion 2. Therefore, automation at the time of measurement can be facilitated and mass productivity can be increased, and measurement efficiency at the time of production can be increased by shortening the measurement time.
[0028]
Although the embodiment has been described in detail, the present invention is not limited to such an embodiment, and the configuration, shape, method, and the like of the detail can be arbitrarily changed and changed without departing from the gist of the present invention. Can be added or deleted.
[0029]
For example, although the substrate B (spacer projection Wss) of a color filter used in a liquid crystal display is illustrated as the measured object W (microscopic portion Ws), any other measured object W (fine Shape part Ws) can be applied. In addition, the Mirau interferometer is illustrated as an optical interferometer using the optical interferometry, but other optical interferometers such as a linic interferometer and a Twyman-Green interferometer are not excluded. Furthermore, focusing processing was performed at the stage of the detection processing, but after measuring the distance and moving it, correcting the height based on the measurement result, etc., as long as the effects of the present invention are not lost, the detailed processing procedure etc. The change of is optional.
[0030]
On the other hand, in the above-described embodiment, the case where the measurement mechanism Fs is moved using the X-axis direction movement mechanism 25 has been described. However, as shown in FIG. The same can be achieved by attaching the same preliminary measurement unit 2 and main measurement unit 3 to the base unit 63 fixed to the rotating shaft 62 of 61 and rotating the main measurement unit 3 in the direction indicated by the arrow R by a certain angle.
[0031]
【The invention's effect】
As described above, the method for measuring the size of a minute shape portion (dimension measuring device) according to the present invention includes a preliminary measurement unit that detects a position including at least the height direction of the minute shape portion and a method of measuring the height of the minute shape portion by an optical interference method. The main measurement unit to be measured is set to have a fixed positional relationship, and at the time of measurement, the preliminary measurement unit detects the minute shape portion and performs positioning with respect to the minute shape portion. The height measurement of the minute shape portion is performed by moving the main measuring portion at the reference position by moving the main measuring portion at the set distance based on the above, and the following remarkable effects are obtained.
[0032]
(1) The preliminary measurement unit can be used to accurately and quickly position the main measurement unit with respect to the minute shape part, thereby facilitating automation at the time of measurement, improving mass productivity, and measuring time. The measurement efficiency at the time of production can be improved by shortening the measurement time.
[0033]
(2) According to a preferred embodiment, a particularly good result can be expected by applying the minute shape portion to the spacer projection integrally formed on the substrate for providing the minute gap.
[0034]
(3) According to a preferred embodiment, if the preliminary measurement unit measures the distance from the top to the minute shape part and performs the focusing process, the main measurement unit is simply moved by the set distance and the main measurement unit is moved. It can be easily and reliably set at the reference position for measuring the height of the minute shape portion.
[0035]
(4) According to a preferred embodiment, a transport mechanism for sequentially transporting a plurality of objects to be measured and stopping at a predetermined measurement position is provided, and a plurality of measurement units are provided in a direction perpendicular to the transport direction of the transport mechanism. If they are arranged, they can contribute to further improvement in mass productivity and measurement efficiency.
[Brief description of the drawings]
FIG. 1 is a schematic front configuration diagram of a dimension measuring device according to a preferred embodiment of the present invention,
FIG. 2 is a schematic plan view showing the entire structure including a transport mechanism of the dimension measuring apparatus;
FIG. 3 is an intensity curve diagram of interference fringes generated when an optical interference method is used;
FIG. 4 is a display screen diagram of a display provided in the dimension measuring device,
FIG. 5 is another display screen view of a display provided in the same dimension measuring device;
FIG. 6 is a flowchart showing a processing procedure by a dimension measuring method according to a preferred embodiment of the present invention;
FIG. 7 is a schematic front configuration diagram showing a state in which a measurement mechanism unit in the dimension measurement device is set at a detection position.
FIG. 8 is a schematic plan view showing a part of a dimension measuring apparatus according to a modified embodiment of the present invention;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Dimension measuring device 2 Preliminary measuring part 3 Main measuring part 4 Transport mechanism part 11 Distance measuring sensor W Object to be measured Ws Micro-shaped part Ws Spacer protrusion H Height of micro-shaped part Ls Set distance Ps Reference position B Substrate Fs Measuring mechanism Section Fm Moving mechanism section M Measurement unit T Transport direction

Claims (8)

In the method for measuring the size of a minute shape portion by measuring the height of the minute shape portion in an object to be measured by an optical interference method, a preliminary measurement unit that detects a position including at least the height direction of the minute shape portion and the minute shape portion The main measurement unit that measures the height by the optical interference method is set in a fixed positional relationship, and at the time of measurement, the preliminary measurement unit detects the minute shape portion and performs positioning with respect to the minute shape portion. The height of the minute shape portion is measured by moving the main measurement portion by a set distance based on the fixed positional relationship, and positioning the main measurement portion at a reference position. Measuring method. The method for measuring the size of a minute shape portion, wherein the minute shape portion is a spacer protrusion integrally formed on a substrate for providing a minute gap. 2. The method according to claim 1, wherein the light interference method uses a white light interference method. The method according to claim 1, wherein the preliminary measurement unit measures a distance from at least an upper portion to the minute shape portion to perform a focusing process. In the dimension measuring apparatus for a minute shape portion that measures the height of the minute shape portion in the object to be measured by an optical interference method, a preliminary measurement unit that detects a position including at least a height direction of the minute shape portion and the minute shape portion A measurement mechanism that sets the main measurement unit that measures the height by the optical interference method in a fixed positional relationship, and performs the positioning with respect to the minute shape by detecting the minute shape by the preliminary measurement unit, and performs the main measurement. A moving mechanism unit that moves the unit by a set distance based on the fixed positional relationship and thereby moves the unit to a reference position for measuring the height of the minute shape unit. Dimension measuring device. The dimension measuring device according to claim 5, wherein the preliminary measurement unit includes a distance measuring sensor that measures a distance from at least an upper portion to the minute shape portion and performs a focusing process. 6. The dimension measuring device for a micro-shaped portion according to claim 5, further comprising a transport mechanism for sequentially transporting a plurality of objects to be measured and stopping at a predetermined measurement position. 8. The apparatus according to claim 7, wherein a plurality of the measurement units are arranged in a direction perpendicular to a transport direction of the transport mechanism.

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