JP3670627B2 - Method and apparatus for measuring dimension of minute shape portion - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for measuring a dimension of a micro-shaped part suitable for use in measuring the height of a micro-shaped part in an object to be measured by an optical interference method.
[0002]
[Prior art]
Conventionally, methods (apparatuses) for measuring the shape of a minute shape portion in a measurement object by optical interference method are disclosed in Japanese Patent Laid-Open No. 8-502828, Japanese Patent Laid-Open No. 9-503065, Japanese Patent Laid-Open No. 10-62139, and the like. In particular, as a method (apparatus) for measuring the height of a minute shape portion, a height measuring method and apparatus disclosed in Japanese Patent Laid-Open No. 8-327327 are known.
[0003]
In shape measurement (height measurement method) using optical interferometry (white light interferometry), first, a white light with a short coherence distance is irradiated from a white light source onto a half mirror in a two-beam interference optical system, and the reference light And the reference light and the measurement light are caused to interfere with each other to generate interference fringes. At this time, if the distance between the measurement optical path and the reference optical path is the same, the luminance of the interference fringe is maximized, so the distance of the measurement optical path is changed relative to the reference optical path, and the generated interference fringe is imaged. By obtaining a maximum optical path difference by image processing, the three-dimensional shape (Z-axis height) of the object to be measured is measured.
[0004]
[Problems to be solved by the invention]
By the way, in the color filter used for the liquid crystal display, the spacer protrusion is integrally formed on the substrate because it is necessary to provide a minute gap. The spacer protrusions are usually formed to have a height of about 5 micrometers, and are provided at intervals of about several hundred micrometers, and the height of the spacer protrusions needs to be within a certain tolerance. Therefore, the height is measured in the inspection process to check whether it is within the tolerance.
[0005]
However, when such a spacer projection is inspected on the production line, it is not easy to find a reference position for starting measurement by the optical interferometry in the conventional height measuring method and apparatus using the optical interferometry. , Usually relies on how to move to the estimated position. For this reason, there is a low probability of finding an accurate position, which eventually leads to a decrease in measurement efficiency due to the time required for measurement, and it is not easy to establish automation at the time of measurement, resulting in inferior mass productivity. there were.
[0006]
The present invention solves such a problem existing in the prior art, facilitates automation during measurement and increases mass productivity, and improves measurement efficiency during production by reducing measurement time. An object of the present invention is to provide a method and an apparatus for measuring a dimension of a minute shape portion.
[0007]
[Means for Solving the Problems and Embodiments]
In the method for measuring the dimension of the minute shape portion according to the present invention, the height H of the spacer protrusion Wss that becomes the minute shape portion Ws integrally formed on the substrate B for providing the minute gap in the workpiece W is measured by the optical interference method. In this case, the preliminary measurement unit 2 that detects a position including at least the height direction of the minute shape portion Ws and the main measurement unit 3 that measures the height H of the minute shape portion Ws by white light interferometry are set in a certain positional relationship. During measurement, the preliminary measurement unit 2 detects the minute shape portion Ws and positions the minute shape portion Ws. Thereafter, the main measurement unit 3 is moved by a set distance Ls based on a certain positional relationship, The main measurement unit 3 is positioned at the reference position Ps to measure the height of the minute shape portion Ws.
[0008]
On the other hand, the dimension measuring device 1 of the minute shape portion Ws according to the present invention uses the height H of the spacer projection Wss that becomes the minute shape portion Ws integrally formed on the substrate B for providing a minute gap in the object W to be measured. An apparatus for measuring by interferometry, a preliminary measurement unit 2 for detecting a position including at least the height direction of the minute shape portion Ws, and a main measurement unit 3 for measuring the height H of the minute shape portion Ws by white light interferometry. Is positioned with respect to the minute shape portion Ws by detecting the minute shape portion Ws by the preliminary measurement unit 2, and the main measurement unit 3 is set with a set distance based on the certain position relationship. It is characterized by comprising a measuring unit M having a moving mechanism portion Fm positioned at a reference position Ps for measuring the height of the minute shape portion Ws by being moved by Ls.
[0009]
In this case, the dimension measuring apparatus 1 includes a transport mechanism unit 4 that sequentially transports a plurality of objects to be measured W and stops at a predetermined measurement position, and in a direction perpendicular to the transport direction T of the transport mechanism unit 4. A plurality of measurement units M can be arranged.
[0010]
【Example】
Next, preferred embodiments according to the present invention will be given and described in detail with reference to the drawings.
[0011]
First, the structure of the dimension measuring apparatus 1 according to the present embodiment will be described with reference to FIGS. In addition, the to-be-measured object W of an Example is the board | substrate B of the color filter used for a liquid crystal display, and the micro shape part Ws is the processus | protrusion Wss for spacers integrally formed on this board | substrate B. FIG. The dimension measuring apparatus 1 (dimension measuring method) according to the present example can be applied to such a spacer projection Wss, and a particularly good result (effect) can be expected.
[0012]
As shown in FIG. 1, the dimension measuring apparatus 1 includes a measurement unit M having a measurement mechanism unit Fs and a movement mechanism unit Fm. 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 certain positional relationship therebetween. .
[0013]
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 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 detected as coordinate points by picking up an image of the workpiece W from above by the CCD camera 10 provided in the preliminary measurement unit 2 and performing image processing. The position in the Z-axis direction is measured by the distance measuring sensor 11 from the upper side to the minute shape portion Ws. In this case, in the Z-axis direction, when measuring the position, the measuring unit M is displaced in the Z-axis direction by using the moving mechanism unit Fm, and the positioning in the height direction is simultaneously performed by performing a focusing process. In addition, if the setting position (X-axis direction position) of the workpiece W in the transport mechanism unit 4 to be described later and the transport amount (Y-axis direction position) with respect to the workpiece W are set, 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 for the preliminary measurement unit 2 can also be used as a CCD camera in an image processing inspection process for detecting defects such as scratches or foreign matter adhesion on the workpiece W.
[0014]
On the other hand, the main measurement unit 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 example 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 disposed on the lateral side of the half mirror 13, an optical fiber 15 for causing white light from the white light source 12 to enter the illumination lens 14 from the horizontal direction, and above the half mirror 13. The image forming lens 16 disposed, the objective lens 17 disposed below the half mirror 13, the half mirror 18 disposed horizontally below the objective lens 17, and a micro mirror disposed between the half mirror 18 and the objective lens 17. 19, a piezo actuator 20 that changes the measurement optical path (measurement distance), and a CCD camera 21 disposed above the imaging lens 16.
[0015]
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 certain positional relationship. It has a function of being positioned at the reference position Ps for measuring the height of the minute shape portion Ws. That is, the movement mechanism unit Fm includes an X-axis direction movement mechanism unit 25 that moves the measurement mechanism unit Fs in the X-axis direction, and a Z-axis direction movement mechanism unit 26 that moves the X-axis direction movement mechanism unit 25 in the Z direction. The Y-axis direction moving mechanism unit 27 for moving the Z-axis direction moving mechanism unit 26 in the Y direction is provided, thereby moving the measurement mechanism unit Fs in the X-axis direction, the Y-axis direction, and the Z-axis direction. Can do.
[0016]
Furthermore, 31 is a controller with a built-in computer processing function, which executes sequence control, data processing, and the like for the dimension measuring method according to the present embodiment. In relation to the measurement mechanism unit Fs, the controller 31 receives signals 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 that performs processing (image processing) is provided, and an X-axis driver unit 35 that drives and controls 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 unit 36 that controls driving and a Y-axis driver unit 37 that controls driving of the Y-axis direction moving mechanism unit 27 are provided.
[0017]
The controller 31 includes a display (monitor) for monitoring the measurement state. 4 and 5 show examples of display screens on the display. FIG. 4 is a display screen V1 mainly showing measurement data and determination results of the measurement data, and an image data display unit showing the positions of the minute shape portion Ws in the X-axis direction and the Y-axis direction by XY coordinates. 41, an image data display unit 42 indicating the position of the minute shape portion Ws in the X-axis direction and the Z-axis direction in the X-Z coordinates, a numerical data display unit 43 for displaying various numerical data, and the display shown in FIG. The screen V2 includes a three-dimensional display unit 44 that three-dimensionally displays the minute shape portion Ws (spacer protrusion Wss).
[0018]
As shown in FIG. 2, the measurement unit M having such a measurement mechanism unit Fs and a movement mechanism unit Fm is attached to the transport mechanism unit 4 constituting the production line to constitute the entire dimension measurement apparatus 1. In this case, the transport mechanism unit 4 has a function of sequentially transporting the plurality of objects W to be measured arranged in two horizontal rows and stopping at a predetermined measurement position. Also, a plurality of measurement units M (four in the embodiment) are prepared, and each measurement unit M is arranged in a direction perpendicular to the transport direction T of the transport mechanism unit 4. If a plurality of measurement units M are arranged in this way, it can contribute to further improvement of mass productivity and measurement efficiency.
[0019]
Next, the operation (function) of the dimension measuring apparatus 1 including the dimension measuring method according to the present embodiment will be described according to the flowchart shown in FIG. 6 with reference to FIGS.
[0020]
First, the object to be measured W is transported in the transport direction indicated by the arrow T by controlling the transport mechanism 4 (step S1). Then, the conveyance is stopped at a 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 moving mechanism unit 25, that is, the detection position Pd for detecting the minute shape portion Ws by the preliminary measurement unit 2, and therefore at this position. Then, detection processing for the minute shape portion Ws is executed (step S4). The detection processing includes not only detection but also positioning processing of the measurement mechanism unit Fs with respect to the minute shape portion Ws based on the detection result.
[0021]
In the detection process, 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 portion Ws in the X-axis direction and the Y-axis direction is detected as a coordinate point by image processing. If 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. The distance measuring sensor 11 in the part 2 is displaced so that the detection center is located at the upper end of the minute shape part Ws, and the Z-axis direction moving mechanism part 26 is driven and controlled by the Z-axis driver part 36 so that the preliminary measuring part 2 is moved to the Z-axis. Focusing processing is performed by displacing in the direction. If the setting position (X-axis direction position) of the workpiece W in the transport mechanism unit 4 is set and the transport amount (Y-axis direction position) with respect to the workpiece W is set, the X in the preliminary measurement unit 2 is set. Position detection (positioning) in the axial direction and the Y-axis direction is not necessary.
[0022]
When the detection process by the preliminary measuring unit 2 is completed, the X-axis driver unit 35 controls the X-axis direction moving mechanism unit 25 to move the measuring mechanism unit Fs by the set distance Ls (steps S5 and S6). Thereby, the main measurement part 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 with a certain positional relationship, the set distance Ls is set based on this certain positional relationship, that is, the detection center of the preliminary measurement unit 2 and the main measurement unit 3 The distance between the measurement centers of the measurement unit 3 is set as the set distance Ls.
[0023]
As described above, if positioning is performed 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 using the preliminary measurement unit 2, the measurement is performed by the X-axis direction moving mechanism unit 25. The main measurement unit 3 can be easily and reliably set at the reference position Ps for measuring the height of the minute shape portion Ws by simply moving the mechanism unit Fs by the set distance Ls.
[0024]
If the main measurement unit 3 is set at the reference position Ps, the main measurement unit 3 performs a measurement process for measuring the height of the minute shape portion Ws (step S7). At the time of measurement, white light from the white light source 12 enters the objective lens 17 through the optical fiber 15, the illumination lens 14, and the half mirror 13. The white light is focused by the objective lens 17, but half the amount of light is reflected by the half mirror 18 and is incident on the minute mirror 19, and the remaining half amount of light is transmitted through the half mirror 18 and emitted downward. Further, the light reflected from the minute shape portion Ws and the light reflected from the minute mirror 19 return to the half mirror 18 again, where interference fringes are generated. The luminance of the interference fringes becomes the highest when the distance from the half mirror 18 to the minute mirror 19 matches the optical path length of the light reflected on the minute shape portion Ws. At this time, since the phases match regardless of the wavelength of the light, an interference fringe with the highest luminance is generated, and on the other hand, the phase difference increases for each wavelength of the light by moving away from the coincidence point. The brightness (intensity of interference) decreases rapidly.
[0025]
Therefore, if the objective lens 17 is continuously moved in the optical axis direction while paying attention to the reference position Ps, an interference fringe intensity curve K 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 the objective lens 17 is intermittently moved in the optical axis direction to capture an image. For example, the luminance data of the interference fringes is stored in the memory in the controller 31, and the 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 captured two-dimensionally, the height H of the minute shape portion Ws can be measured with high accuracy.
[0026]
Such processing can be performed in parallel independently for each measurement unit M shown in FIG. And each to-be-measured object W ... is sequentially conveyed by the conveyance mechanism part 4, and the same measurement process is repeatedly performed (step S8, S9). Therefore, according to such a dimension measuring method (dimension measuring apparatus 1) of the minute shape portion Ws, the preliminary measurement unit 2 can be used to accurately and quickly position the main measurement unit 3 with respect to the minute shape portion Ws. Therefore, the automation during measurement can be facilitated to increase mass productivity, and the measurement efficiency during production can be increased by shortening the measurement time.
[0027]
As described above, the embodiments have been described in detail. However, the present invention is not limited to such embodiments, and the detailed configuration, shape, technique, and the like can be arbitrarily changed without departing from the gist of the present invention. Can be added or deleted.
[0028]
For example, although the Mirau interferometer is illustrated as an optical interferometer using the optical interferometry, other optical interferometers such as a linic interferometer and a Twiman Green interferometer are not excluded. Furthermore, focusing processing was performed at the detection processing stage. After measuring and moving the distance, the height is corrected based on the measurement result. The change of is optional.
[0029]
On the other hand, in the above-described embodiment, the measurement mechanism unit Fs is moved by using the X-axis direction moving mechanism unit 25. However, as shown in FIG. The same preliminary measurement unit 2 and main measurement unit 3 are attached to the base portion 63 fixed to the rotary shaft 62 of 61, and can be similarly implemented by rotating in a range of a predetermined angle in the direction indicated by the arrow R.
[0030]
【The invention's effect】
As described above, the dimension measuring method (dimension measuring apparatus) of the minute shape portion according to the present invention optically measures the height of the spacer projection that becomes the minute shape portion integrally formed on the substrate for providing the minute gap in the object to be measured. When measuring by interferometry, the preliminary measurement unit that detects the position including at least the height direction of the micro-shaped part and the main measurement unit that measures the height of the micro-shaped part by white light interferometry are set in a certain positional relationship. At the time of measurement, the preliminary measurement unit detects the minute shape portion and performs positioning with respect to the minute shape portion. Thereafter, the main measurement portion is moved by a set distance based on a certain positional relationship, and the main measurement portion is moved to the reference position. Since the height of the micro-shaped portion is measured by positioning it in the position, the following remarkable effects can be obtained.
[0031]
(1) Since the preliminary measurement unit can be used to accurately and quickly position the main measurement unit with respect to the minute shape part, it is easy to automate the measurement and increase the mass productivity, and the measurement time The measurement efficiency at the time of production can be increased by shortening the length, and in particular, good results can be expected when applied to the measurement of spacer protrusions integrally formed on a substrate for providing a minute gap.
[0032]
(2) According to a preferred embodiment, a transport mechanism unit that sequentially transports a plurality of objects to be measured and stops at a predetermined measurement position is provided, and a plurality of measurement units are arranged in a direction perpendicular to the transport direction of the transport mechanism unit. If arranged, it can contribute to further improvement of mass productivity and measurement efficiency.
[Brief description of the drawings]
FIG. 1 is a schematic front view of a dimension measuring apparatus according to a preferred embodiment of the present invention;
FIG. 2 is a schematic plan view of the entire structure including a transport mechanism of the same dimension measuring device,
FIG. 3 is an intensity curve diagram of interference fringes generated when optical interferometry is used;
FIG. 4 is a display screen diagram of a display provided in the same dimension measuring device,
FIG. 5 is another display screen diagram 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 of a state in which the measurement mechanism unit of the same dimension measurement device is set at a detection position;
FIG. 8 is a schematic plan configuration diagram 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 measurement apparatus 2 Preliminary measurement part 3 Main measurement part 4 Conveyance mechanism part W Measured object Ws Minute shape part Wss Spacer protrusion H Height of minute shape part Ls Setting distance Ps Reference position B Substrate Fs Measurement mechanism part Fm Movement mechanism Part M Measuring unit T Transport direction

Claims (4)

  In a method for measuring a dimension of a micro-shaped part that measures the height of a spacer projection, which is a micro-shaped part integrally formed on a substrate for providing a micro gap in an object to be measured, by the optical interference method, at least the height of the micro-shaped part is measured. A preliminary measurement unit for detecting a position including a direction and a main measurement unit for measuring the height of the minute shape part by white light interferometry are set in a fixed positional relationship, and the minute shape part is measured by the preliminary measurement unit during measurement. Is detected and positioned with respect to the minute shape portion, and thereafter, the main measurement portion is moved by a set distance based on the fixed positional relationship, and the main measurement portion is positioned at a reference position to thereby position the minute shape. A method for measuring a dimension of a minute shape part, wherein the height of the part is measured.   In a dimension measuring apparatus for a minute shape portion that measures the height of a spacer projection as a minute shape portion integrally formed on a substrate for providing a minute gap in an object to be measured by an optical interference method, at least the height of the minute shape portion is measured. A preliminary measurement unit that detects a position including a direction, a measurement mechanism unit that sets a main measurement unit that measures the height of the minute shape part by white light interferometry in a fixed positional relationship, and the minute shape by the preliminary measurement unit A moving mechanism for positioning the micro-shaped part by detecting the part and positioning the main measuring part at a reference position for measuring the height of the micro-shaped part by moving the main measuring part by a set distance based on the fixed positional relationship And a measurement unit having a measuring part.   The apparatus for measuring a dimension of a minute shape part according to claim 2, further comprising a conveyance mechanism unit that sequentially conveys a plurality of objects to be measured and stops at a predetermined measurement position.   The apparatus for measuring a dimension of a minute shape part according to claim 3, wherein a plurality of the measurement units are arranged in a direction perpendicular to the conveyance direction of the conveyance mechanism unit.

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