JPH09329420A - Micro-dimension measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring method and device which can simplify and make accurate the measuring operations. SOLUTION: In this measuring method to perform measurement of a work in comparison to the data stored in advance, the edge of a work to be measured is sensed by a sensing tool by scanning from the central region P of the tool S toward its peripheral region upon selecting one of the scanning directions provided. To perform edge sensing, the relative positioning of the tool S with the work is changed, and the scanning direction of the tool part is turned oppositely when the central region P of the tool S goes beyond the edge.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring method for measuring a work to be measured in comparison with data of a drawing or data stored in advance regarding a reference work or the like,
For example, the present invention relates to a method for measuring minute dimensions of a work such as a plastic molded product, a mold, and a lead frame.

[0002]

2. Description of the Related Art Conventionally, this type of measuring method has been performed by a measuring microscope or a universal tool microscope.

Typical examples of the work include a lead frame of an electronic component, a molded plastic product, and a mold for molding these.

A conventional manual measuring microscope has a reference work (a reference work having a desired shape, size, etc.) and a work to be measured (hereinafter referred to as a drawing or a reference work, having the same dimensions as the reference work). The work manufactured in Fig. 3 is displayed on the display unit (hereinafter also referred to as the monitor screen) in an enlarged image of the work to be measured), and the moving distance in the X and Y directions that is manually performed by rotating the knob is displayed on the magnet. The moving distance is detected by a scale, an optical scale or the like, and the detected moving distance is displayed on the counter. The operator gazes at both the work image on the monitor screen and the numerical value displayed on the counter, and operates the microscope by relying on them.

A conventional general method of measuring a work will be described. First, the places of the work that need to be strictly controlled in size are determined in advance, and those places are set as measurement points on the drawing. Thereafter, reference coordinate data is actually obtained using the reference work. For example, a reference work is set on the stage of a microscope. Then, the coordinates of each measurement point of the reference work are measured. By processing the coordinate data obtained by the measurement with an arithmetic processing unit,
Obtain the size of the reference work. Such a measuring operation is generally called teaching. After the teaching, the workpiece to be measured to be measured is set on the microscope stage. Then, the coordinates of each measurement point of the work to be measured are measured. The dimensions of the work to be measured are obtained by processing the coordinate data obtained by the measurement by an arithmetic processing unit. At this time, coordinate data of the reference work (specifically, dimension data calculated based on coordinate data obtained for the reference work) is compared and evaluated while measuring the work to be measured.

An example of the measurement procedure in the conventional measuring microscope and universal tool microscope will be described in more detail below.

Setting of measurement points A plurality of points whose dimensions are to be strictly controlled in the work are determined in advance and those points are set as measurement points on the drawing.

With respect to the teaching reference work, the coordinate system data of a plurality of measurement points set in advance on the drawing is read into the microscope apparatus. The procedure is as follows.

First, the reference work is placed on the stage.

Setting the origin on the reference work.

While moving the stage in the x and y directions, the position on the reference work corresponding to the preset measurement point on the drawing is aligned with the detection tool (for example, a cross reticle) in the center of the monitor image.

If the location is correct, the switch button is pressed to determine the location as the measurement point. By determining the measurement point, the coordinate data is stored in the processing unit.

Similarly, for other measurement points set in advance, coordinate data is sequentially input for each corresponding measurement point. In the case of a circular shape, the shape and dimensions of the circle are determined by setting three points as measurement points.

When the measurement points on the reference work are input, the teaching ends.

Measurement / measurement of the work to be measured A work (work to be measured) manufactured with the reference work as a reference is arranged on the stage, and the origin of the work to be measured is set in correspondence with the origin of the reference work.

When the measurement of the work to be measured is started, the relative coordinates up to the next measurement point are subtracted and displayed on the counter.
(This subtraction display is a rough indication that the point corresponding to the measurement point is displayed on the monitor screen of the monitor device.)-The position corresponding to the measurement point is set at the center of the monitor screen based on the display content on the monitor screen. Measure coordinate data according to the detection tool (cross reticle).

When the coordinate data of each measurement point of the work to be measured is obtained, the measurement of the work to be measured is completed.

[0018]

In conventional scanning, only one direction from one end of the detection tool to the other end is passed so that the edge to be measured is passed when measuring or storing the measuring procedure. It was scanning. Then, when it is desired to scan in the opposite direction, the scanning direction is reversed by operating a mouse or a button. In this case, the operator has to release the handle for moving the stage and move the hand to the mouse or button. This deteriorates work efficiency.

The edge portion to be measured may not only extend along the X and Y axes, but may also extend obliquely with respect to the X and Y axes. In scanning, the measurement point was detected by scanning along the X and Y axes, that is, in the vertical or horizontal direction.

If the contour of the workpiece is inclined with respect to the X- and Y-axis directions near the measurement point, one edge of the contrast to be detected when the edge is obtained (a gradual change) is generated. Highly accurate edge detection could not be performed.

For such an edge extending in the oblique direction, it is necessary to specify a scanning direction which is close to a right angle to the edge, but in order to do so, the operator is oblique to the X and Y axes. It is necessary to perform a special operation so as to extend in the direction and specify the start point and the end point of the scan. Therefore, it is necessary to manually perform a complicated designation operation in consideration of the rotation component of the scanning range.

Furthermore, the change from light to dark during the scanning,
In addition, the operator's manual detailed designation is also required for the change from dark to bright.

Further, when the designation is performed by eye alignment, it is necessary to rotate the cross reticle so as to be parallel to the edge and then perform the alignment.

It is an object of the present invention to provide a measuring method which makes the measuring operation easier and more accurate.

[0025]

The gist of the present invention is the measuring method according to any one of claims 1 to 7.

[0026]

【The invention's effect】

(1) According to the present invention, in the case of manual measurement, the scanning direction of the detection tool can be changed simply by operating the handle for moving the stage. Therefore, it is easy to improve work efficiency. Even in the case of automatic measurement, the scanning direction of the detection tool can be changed only by controlling the handle operation for moving the stage. (2) When scanning in eight peripheral directions from the central area of the rectangular detection tool, the orientation of the edge is recognized and the scanning direction is nearly perpendicular to the edge direction even if the measurement edge extends in the oblique direction. Since it is possible to select, it is possible to reduce the operation for specifying a troublesome detection condition. Not only that, the edge of the workpiece to be measured can be automatically detected with high accuracy. (3) When scanning in eight peripheral directions from the central area of the rectangular detection tool, if the detection tool is set in a direction perpendicular to the edge direction, unlike the conventional detection tool, the scanning is performed in the X and Y axes. Not limited to only the direction, even if the contour of the workpiece near the measurement point is oblique with respect to the X and Y axis directions, the contrast detected when obtaining the edge is sagging in one direction (a gradual change) Can be avoided. As a result, highly accurate edge detection can be performed. (4) When the change in contrast is detected by scanning in the direction perpendicular to the edge, it is possible to strictly detect the change position of the contrast necessary for detecting the edge. The distance between the position where the change starts and the position where the change ends becomes short, and the position of the edge can be detected exactly. Further, it is possible to efficiently detect a change in contrast and prevent erroneous detection due to dust or the like. (5) If the detection tool always detects edges in the direction from the one having the smallest unevenness of light and dark to the most, it is possible to prevent erroneous detection due to dust. To describe this point in detail, in the case of a tool microscope, if dust is present on the stage, automatic detection by image processing causes the detection tool to catch the dust, which causes a change in contrast. , There is a risk of accidentally detecting it as a boundary. However, in the case where the lightness and darkness unevenness is increased in the direction from the least to the most, the first change in contrast becomes the boundary portion of the work, so that the influence of dust is reduced. Therefore, erroneous detection due to dust can be prevented.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION When the present invention is applied to a measuring method of a type in which a moving part (stage) is manually moved, the effect is particularly remarkable. However, not only such a type but also a motor or the like can be used. It can also be applied to a mode in which it is automatically moved. Since the aspect of manually moving the moving part (stage) is preferable for the present invention, the outline of the configuration and the measurement procedure of the manual aspect will be described.

Measuring Device The measuring device according to the present invention is a measuring device comprising a drive system, an observation system and a control system, and the drive system comprises a moving part (for example, X
X stage that moves in the direction, Y stage that moves in the Y direction), a handle and / or a motor that moves the X and Y stages, and the control system has an arithmetic processing unit. Has a host computer and an image processing device that are electrically connected to each other.

Setting of measurement points A desired number of measurement points is set on the drawing for the work. For example, a plurality of places where dimensions must be strictly controlled are set on the drawing.

Examples of the first aspect of the teaching teaching, and stores the drawing data directly. As a second aspect of teaching, various data of a reference work (a reference work manufactured based on the data of the drawing is referred to as a reference work in this specification) is measured by a measuring device and stored. Hereinafter, an example of the second aspect of teaching will be described.

The reference work is placed on the stage of the measuring device.

Setting the origin on the reference work. For example, two small holes are made in the reference work for setting the origin, and the work origin is determined by measuring the positions of the two small holes. For setting the origin, another conventional method may be adopted.

Move the stage in the x and y directions,
The position on the reference work corresponding to the position of the detection tool set in advance on the drawing is matched on the monitor screen.

-The displayed location of the detection tool is correct,
If the start and end locations are appropriate, determine the location of the detection tool. At this time, it is preferable to determine the position of the detection tool by specifying the coordinate value of the start point and the distance in the X and Y directions from the coordinate value.

When the position of the detection tool is determined, the data is stored in the arithmetic processing unit.

The position of the detection tool is sequentially input for each measurement point of the actual work reference work corresponding to the other measurement points set in advance on the drawing for the reference work.

When all the detection tool positions on the reference work have been input, the teaching based on the reference work ends.

A workpiece manufactured based on the measurement / drawing of the workpiece to be measured or the reference workpiece (this workpiece is referred to as a workpiece to be measured in this specification) is arranged on the stage, and the origin is set in the same manner as the reference workpiece. .
At that time, even if the position of the workpiece to be measured on the stage is different from the position of the reference workpiece, the positional deviation is automatically corrected by the arithmetic processing. This eliminates the need for manual alignment between the two.

The operator manually moves the stage in the x-direction and the y-direction while observing the direction and the length of the movement mark of the figure (for example, arrow) displayed on the monitor screen.

When the detection tool and / or the measurement point appears and is displayed on the monitor screen, the movement mark disappears from the monitor image, and the detection tool of the detection tool stored in advance based on the drawing or the reference work is displayed. Some or all are displayed on the monitor screen.

When there is a dimensional deviation between the workpiece to be measured and the reference workpiece being measured on the monitor screen, the position where the contour of the workpiece to be measured crosses the detection tool is displaced.

At this time, if the deviation is within the range intersecting with the displayed detection tool, the contour of the workpiece to be measured can be detected by this detection tool, and the coordinate data of the measurement point is displayed.

By setting this measurement point as "fixed", the measurement data is captured.

If the detection tool and the contour of the work to be measured do not intersect due to this deviation, the detection tool displaying the contour of the work to be measured cannot detect it, so the coordinate data of the measurement point is not displayed. Therefore, it will be an error even if you confirm it.

In this case, by setting the detection tool again so that the contours of the tool to be measured intersect, the coordinate data of the measurement point can be displayed, and the measurement data can be fetched by "decision".

When the coordinate data of each measurement point is obtained,
The measurement ends.

Next, the outline of the configuration will be described.

Detection Tool The detection tool used in the present invention is a line tool or an area tool, and is constituted by a figure such as a single arrow (in the case of the line tool) or a rectangle (in the case of the area tool), It has a start point and an end point. Whether the single arrow (line tool) or each tool part of the rectangular detection tool (area tool) has an arrow shape, the tip of the arrow is the end point, and the direction of the arrow detects the scanning direction (or contrast). Direction). The starting point is the detection tool (center area)
Can be the center or the arrowhead. The point where the detection tool and the edge intersect is taken as the detection point, and that point is estimated as the measurement point.

The main features of the detection tool used in the present invention are as follows.

(A) The detection tool is configured to scan from the central region in a plurality of peripheral directions. For example, in the case of a line tool, scanning is performed in two directions opposite to each other. In the case of a rectangular area tool, a mode of a tool portion that scans in four directions of a cross, a tool portion that scans in the four directions of the cross, and a tool that scans in four diagonal directions of the X shape A combination of a portion and a portion is preferable. In the latter case, scanning can be performed in a total of 8 directions.

(B) The size and shape of the detection tool are variable.

(C) The contour near the measurement point of the workpiece to be measured is recognized by performing a plurality of scans in the vicinity of the measurement point, and based on this, the scanning of the detection tool is performed in the direction perpendicular to the edge direction or in the direction close thereto. Set automatically.

(D) The scanning direction can be changed by moving the detection tool so that the central region of the detection tool crosses the edge.

(E) Edges can always be detected by scanning in the direction from the one with the smallest unevenness of light and dark to the one with the most.

(F) The minimum size of the central area of the detection tool corresponds to three or more pixels. When the central area of the detection tool is rectangular, the minimum size of the central area corresponds to three or more pixels in both the vertical and horizontal directions. If the number of pixels is odd and the vertical and horizontal dimensions correspond to three pixels, the total number of all pixels is nine, and the vertical and horizontal dimensions correspond to five pixels. , The total of all pixels is 25. In such a case, it is preferable to set the pixel located at the center of all the pixels to be located at the center of the detection tool.

Moving mark The moving mark is a figure such as an arrow, and indicates the moving direction and moving distance from the current position.

Coordinate System The coordinate system in the measuring apparatus of the present invention does not need to be an absolute coordinate system, but can be configured to depend on the posture with respect to the workpiece to be measured.

Setting of measurement point The position of the measurement point set on the work (reference work and work to be measured) or the detection tool therefor is usually set at an easy-to-understand location such as a corner.

[0059]

1 shows schematically an example of a measuring device according to the invention.

In FIG. 1, the microscope type measuring apparatus mainly comprises a drive system, an observation system and a control system. The drive system includes a moving unit, for example, an X stage 1 that moves in the X direction, a Y stage 2 that moves in the Y direction, an X moving handle 3 that moves the X stage 1 by manual operation of the operator, and a manual operation of the operator. A Y moving handle 4 for moving the Y stage 2 is provided. XY counter 5
Are the X coordinate of the X stage 1 and the Y coordinate of the Y stage 2, respectively.
Count the current position of the coordinates. The work 6 to be measured is X
It is set at a predetermined position on the upper surface of the stage 1.

The workpiece 6 to be measured is illuminated by an illumination mechanism (not shown) by arbitrarily selecting it from the upper surface and the lower surface.

As an observation system, a microscope main body 7 is arranged above the workpiece 6 to be measured, an objective lens portion 8 is provided in a lower portion of the microscope main body 7, and a CC portion is provided in an upper portion.
A D camera 9 is provided.

In the control system, the arithmetic processing unit 18 is arranged, and the host computer 10 and the image processing unit 11 electrically connected to each other are provided therein. The XY counter 5 described above is connected to the host computer 10. A foot switch 12 and a mouse 13 are further connected to the host computer 10. The foot switch 12 is used to determine a measurement point, and the mouse 13
Is used to select a menu or to indicate a detection area. The image processing device 11 includes a CCD camera 9,
The monitoring device 15 is connected.

The image processing device 11 normally receives a field-of-view image in the monitor field of view of the CCD camera 9 as a signal,
Part or all of the visual field image is displayed as a monitor image on a substantially rectangular monitor screen of a CRT. In the illustrated example, the entire field-of-view image is displayed as it is on the monitor screen as a monitor image.

Instead of or in addition to the handles 3 and 4, an X movement motor and a Y movement motor are provided, and these motors and the host computer 10 are connected to each other to connect the X stage 1 and the Y stage. It is also possible to move the stage 2 automatically.

The lead frame shown in FIG. 2 is an example of the work 1 to be measured installed on the X stage 1. A part A of the work (lead frame) is a CCD as a field image.
The image is captured by the camera 9 and displayed on the monitor screen of the monitor device 15 as a monitor image.

FIG. 3 shows an example of a monitor image.

An outline of the measuring procedure in the above-mentioned microscope type measuring apparatus will be described.

First, a desired number of measurement points are set on the drawing for the reference work 6 shown in FIG. For example, as indicated by reference numerals 21 to 32 in FIG. 3, a plurality of locations whose dimensions need to be strictly controlled are set. A small black circle indicates a point (measurement point) where edge detection is desired, and an arrow length indicates a location where width measurement is desired.

There are various modes of teaching.
In the teaching of the first aspect, data of a paper drawing or a drawing of a computer (such as CAD) is stored as it is, or after being processed or modified, stored in a disk or the like. In the teaching of the second aspect, data at a predetermined location on the reference work is measured and stored in a disk or the like. For example, the reference work 6 is placed on the stage 1 (FIG. 1) of the measuring device. After that, the origin is set on the reference work 6. In the example of FIG. 2, the center points O1 and O2 of the two small holes 6a and 6b of the reference work are measured, and the origin of the reference work 6 is set based on them.

Then, the stage 1 is manually moved in the x and y directions.
Is moved, and the location on the reference work corresponding to the first measurement point 21 set in advance in the drawing as shown in FIG. 3 is displayed on the monitor screen 16.

As shown in an example in FIG. 4, a mouse 13 is used to indicate an arrow shape on the monitor screen 16 at a position on the reference work corresponding to the first measurement point (eg, 21 shown in FIG. 3). Set the detection tool of. At this time, enter the coordinate value of the start point of the detection tool (preferably the center of the center area of the detection tool or the barbed portion of each tool portion as the start point as described later), and the end point of the detection tool is the coordinate value. Instead, input the relative position, that is, the distance in the XY directions. Similarly, for the locations on the reference work corresponding to the second to twelfth measurement points (for example, 22 to 32 shown in FIG. 3),
The mouse 13 is used to set an arrow-shaped detection tool on the monitor screen 16.

As a result, the positions of the detection tools corresponding to all the measurement points 21 to 32 shown in FIG. 3 are specified.

FIG. 5 shows an example of the line tool type detection tool R. The detection tool R scans from the central area P in two opposite directions. The center O of the detection tool R is the starting point. W indicates an edge.

In FIG. 5A, the central region P of the detection tool R is located inside the edge W of the work.
An upward tool portion R1 from the center region P crosses the edge W. In such a case, the scratch M inside the edge W
And the like, the measurement point 21 tends not to be located on the edge W but to be located at the flaw M.
Then, a measurement error will occur.

Then, when the Y stage 2 is moved, as shown in FIG.
(B) state. At this time, the central region P of the detection tool R projects outside the edge W, and the downward tool portion R
2 intersects the edge W, and the measuring point 21 is located on the edge W.

In the state of FIG. 5A, the flaw M can be avoided by operating the X stage 1 and shifting the detection tool R to the right or left, but Such a shift may not be preferable depending on the shape and the like.

FIG. 6 shows an example of the rectangular area tool S. Scanning is performed from the central region P of the detection tool S in the four side directions of the cross shape. It is composed of an upward tool part S1, an opposite downward tool part S2, a leftward tool part S3, and an opposite rightward tool part S4, and the center of the whole is zero.

In the state of FIG. 6A, the measuring point 21 is located at the dust M, but the detection tool S is moved. In the state of FIG. 6B, the measurement point 21 is the edge W.
Located on top.

FIG. 7 shows an example of a detection tool S of another area tool type. Four tool parts S1, S2, S3, S4 having a cross shape outward from the central region P and four tool parts S5, S6, S7, S8 having diagonal X-shapes.
Are combined, and the center is 0.

In the state of FIG. 7A, the central area P is located on the edge W. In this case, the Y stage 2 is moved so that the central region P is displaced from the edge W, and the relative position with respect to the work is changed to the upper edge W1 or the lower edge W2 of the edge W. After that, Fig. 7
Right oblique tool part S5 or S7 in (A) of FIG.
The measurement point 21 is obtained by.

For more precise measurement, as shown in FIG. 8B, the shape and size of the detection tool S are changed, and the measurement point 2 is changed by S5 (or S7) in the diagonally right direction.
Ask for 1. In this case, the tool part S5 (or S7)
Is almost perpendicular to the edge W.

In any of the embodiments shown in FIGS. 5 to 7, it is preferable that the size and shape of the detection tools R and S be within a proper search range during automatic measurement.

Further, the central area P functions as a dead zone so that the scanning direction cannot be specified when it is located on the edge W. The size and shape of this central region P may be arbitrarily selected, but it is preferable to make it larger than 3 to 5 pixels of the monitor screen. This enables sharp measurement.

The type (shape and size) of the detection tool R or S can be set arbitrarily. It is preferable to select a type with few measurement errors in consideration of the shape near the measurement point.

Both the rectangular detection tool S and the arrow detection tool R may be shown on the monitor screen 16, or only one may be shown. Of course, a detection tool of another shape (for example, X mark) may be shown. Alternatively, the data may be detected by the rectangular detection tool S and stored in the form of an arrow detection tool passing through the center of the rectangle.

If the locations where the detection tools R and S are displayed are correct and the locations of their start points R1 and end points R2 are appropriate,
The positions of the detection tools R and S are determined.

When the positions of the first detection tools R and S are fixed, the data is stored in the arithmetic processing unit 18.

The same measurement work is performed for each of the measurement points 22 to 32 of the actual reference work corresponding to the other measurement points, and the positions of the detection tools R and S are sequentially input. When the data of the positions of the detection tools R and S corresponding to all the measurement points 21 to 32 and the like on the reference work has been input in this way, the teaching ends.

After the teaching of the drawing or the reference work is completed, the work 6 to be measured is placed on the stage 1 and
Set the origin in the same way as the reference work. At this time, even if the reference work and the work to be measured are arranged at different positions on the stage 1, that is, at positions slightly shifted, the position shift is automatically calculated based on the origin positions of both. Therefore, the operator can install the work 6 to be measured on the stage 1 without performing the alignment operation and without worrying about the displacement of the installation position.

When the measurement point 21 or the detection tools R and S therefor are not displayed on the monitor screen 16, as shown in FIGS. 11 (a) (b) (c), the monitor screen 16 is displayed.
Is displayed with a movement mark T. In the illustrated example, the movement mark T
Is an arrow. The operator manually moves the stage 1 in the x and y directions in the order of (a), (b), and (c) while looking at the direction and length of the movement mark T.

When the measuring point 21 or the detection tools R and S therefor are placed at a predetermined distance from the edge of the monitor screen 16, the types of detection tools R and S previously stored based on the reference work 6 or the drawing are automatically detected. Is displayed. At the same time, the movement mark T disappears from the monitor screen 16.

At this time, if the deviation is within the range intersecting with the displayed detection tool, the contour of the workpiece to be measured can be detected by this detection tool, and the coordinate data of the measurement point is displayed.

By making this measurement point "confirmed", the measurement data is captured.

When the detection tool and the contour of the work to be measured do not intersect due to this shift, the contour of the work to be measured cannot be detected by the detection tool, so the coordinate data of the measurement point is not displayed. Therefore, it will be an error even if you confirm it.

In this case, the coordinate data of the measurement point can be displayed by setting the detection tool again so that the contours of the tool to be measured intersect, and the measurement data is fetched by "decision" there.

When the measurement data corresponding to each measurement point is obtained, the measurement operation ends.

As shown in FIG. 7A, the posture of the edge W is recognized and the detection tool S detects the edge W.
This can be performed by scanning in a direction perpendicular to or close to the direction of the edge W.

For example, when the edge W extends in an oblique direction, a plurality of arrow detection tools Ra and Rb are used to automatically calculate a scanning direction perpendicular to or close to the direction of the edge W. Edge W by the detection tool S
Is detected by the tool portion S5 or S7 which scans in a direction perpendicular to the direction of the edge W (B in FIG. 7) or in a direction close thereto (A in FIG. 7).

Further, the rectangular detection tool S is used to scan a plurality of detection tools in the rectangle to detect the edge W.
The scanning direction perpendicular to or close to the direction is automatically calculated, and the detection tool S detects the edge W by scanning in the direction perpendicular to or close to the direction of the edge W. See FIG.

In any case, the contour near the measurement point 21 of the workpiece to be measured is recognized by performing a plurality of scans in the vicinity of the measurement point 21, and based on this, the contour is perpendicular to or close to the direction of the edge W. The detection tool S can be automatically set as shown in A or B of FIG.

In such a measurement, even if the measurement edge W extends obliquely, the posture of the edge W is recognized and
Since the scanning direction close to a right angle with respect to the direction of the edge W is calculated, it is possible to reduce an operation for designating a troublesome detection condition. In addition, the automatic detection of the edge W of the work to be measured can be performed with high accuracy.

In FIG. 8, one of the small rectangles corresponds to one pixel, and when the edge W is slanted at the pixel level, a pixel where light and dark overlap is on the detection tool R or S. The scanning direction is selected so that it does not exist. All such processing is performed by arithmetic processing (software).

When the detection tool is automatically set in the direction perpendicular to the edge, unlike the conventional detection tool, the scanning is not limited to the X and Y axis directions, and the scanning in the vicinity of the measurement point is performed. Even if the contour of the work is inclined with respect to the X and Y axis directions, it is possible to avoid the occurrence of sag (a gradual change) in one of the contrasts detected when the edge W is obtained. As a result, highly accurate edge detection can be performed.

When the change in contrast is detected by scanning in the direction perpendicular to the edge W, the position of change in contrast necessary for detecting the edge W can be detected exactly. The distance between the position where the change starts and the position where the change ends can be shortened, and the position of the edge W can be detected exactly.

When the distribution of brightness in the rectangular detection tool R or S is detected and scanning is performed between the dark part and the bright part with the edge W as a sag, the direction from the one with less unevenness of light and dark to the more one A method of scanning will be described.

It is preferable that the detection of the edge W by the detection tool R or S is always performed by scanning in the direction from the one with less unevenness of light and dark to the one with more unevenness.

In the example of FIG. 8, the edge W is searched by scanning from the dark portion D to the bright portion L.

FIG. 9A shows the light / dark level when scanning is performed from the lower left position to the upper right position in FIG.
Thereby, the boundary W of the bright portion L is detected as the measurement point 21.

FIG. 9B shows the light-dark level when scanning is performed from the upper right position to the lower left position in FIG.
Thereby, the boundary W of the dark part D is detected as the measurement point 21.

In any of (A) and (B) of FIG.
The scanning direction indicated by the arrow is scanning from the direction with less unevenness in brightness to the direction with more unevenness.

Furthermore, the change in contrast can be detected efficiently, and erroneous detection due to dust M or the like can be prevented. Especially,
If the detection tools R and S detect the edge W in the direction from the side with the less unevenness of light and dark to the direction with more unevenness, the false detection due to the dust M can be prevented.

18 to 20 schematically show a method of shifting the measurement points.

FIG. 19 shows the measurement point 21 of the work 6 to be measured and the detection tools R and S in the monitor image 16 in a state where dust M is present near the measurement point of the work 6 to be measured. In this state, correct measurement is impossible.
That is, the position of the dust M is mistakenly recognized as the position of the edge W.

Therefore, as shown in FIG. 18 or 20,
The positions of the detection tools R and S are shifted in order to change the relationship between the measurement points of the workpiece 6 and the detection tools R and S in the monitor image 16.

FIG. 18 shows a state in which dust M is present near the measuring point of the workpiece 6 to be measured, and the relationship between the measuring point of the workpiece 6 to be measured and the detection tools R and S in the monitor image 16 is changed. It shows the state. In this state,
Correct measurement is possible.

FIG. 20 shows the relationship between the measurement points of the work 6 to be measured and the detection tools R and S in the monitor image 16 in the state where dust is present near the measurement points of the work to be measured, as shown in FIG. 3 schematically shows three methods for shifting the position of the detection tool in order to change to another state.
That is, from the state of FIG. 19, the detection tools R and S are moved upward or leftward and rightward. Further, in this illustrated example, although the edge W is not inclined, if the edge W is inclined, the attitude of the edge W can be recognized using the detection tools Ra and Rb.

In the measuring apparatus of FIG. 1, since the illumination is performed from below the stage 1 (the present invention includes a mode of illuminating from above the stage 1), when the work 6 is placed on the stage 1, There is a shadow. Using the change in contrast between the shadow and the illumination light, the boundary, that is, the edge W is obtained as described above. In the unlikely event that there is garbage M on this stage 1
If there is, it is determined that the automatic detection by image processing is performed as shown in FIG.
As shown in FIG. 3, when the detection tool R or S detects the dust M, there is a possibility that the contrast change due to the dust M is erroneously detected as the edge W. in this case,
By searching using the tool part in the opposite direction,
False detection due to dust M can be prevented. In addition, the detection tool R
Or, the start point and end point of S are slightly shifted and the detection tool Rb
It is also possible to partially change the position of the detection tool Ra or the position of the detection tool Ra so that the edge W can be measured correctly.

FIG. 11 shows an example of movement marks that assist the operator. Next measurement point 21 and stage 1
Alternatively, an arrow T having a direction and a length corresponding to the relative position of the monitor image 16 to the current position is displayed as an example of the movement mark. The movement mark can also be defined as an instruction indicating the direction and amount of movement of the display area on the monitor screen.
The movement mark is best displayed on the monitor image 16, but can be displayed outside the monitor image 16.

11 (a), (b) and (c) show a process in which the monitor image 16 moves toward the measuring point 21 or the detection tool T therefor by moving the stage 1. ing. (A), (b),
In any of (c), the next measurement point 21 or the detection tool T therefor is not within a predetermined distance from the edge of the monitor screen. When the next measurement point 21 or the detection tool T therefor enters a predetermined distance from the edge of the monitor screen, the movement mark T automatically disappears from the monitor image 16. At the same time, the detection tool R or S is displayed on the monitor image 16.

15 to 17 show such a monitor image 16
3 shows an example of a display relationship between the movement mark T and the detection tools R and S (operation mode when semi-automatic measurement of a taught measurement procedure is performed). In the state of FIG. 15, the next measurement point 21 or the detection tool T therefor is not included in the monitor image 16. Next measurement point 21 or detection tool T therefor and stage 1 or monitor image 16
An arrow T (movement mark) having a direction and a length corresponding to the relative position with respect to the current position is displayed in the monitor image 16.

By moving the stage 1, FIG.
As shown in FIG. 6, when the next measurement point 21 or the detection tool T therefor enters the monitor image 16, the moving mark T automatically disappears from the monitor image 16, and at the same time, one of the detection tools R and / or S The part is displayed on the monitor image 16. In the state of FIG. 16, the next measurement point 21 is not included in the monitor image 16, but a part of the detection tools R and / or S is included in the monitor image 16.

When the display of the detection tools R and / or S is assisted by the operator and the stage 1 is further moved, all of the detection tools R and S are displayed on the monitor image 16 as shown in FIG. Then, it will be in the waiting state for confirmation. In this state, the next measurement point 21 is automatically detected. No matter where the measurement point is located on the monitor image 16, it is detected. When the operator determines that the detection point is at the correct position, the point is determined. However, this confirmation operation may be performed later.

Using the movement mark T as described above,
Since the next measurement point 21 or the detection tool T therefor can be visually displayed in which direction and how far from the current position, that is, the moving direction and the moving distance, by using the moving mark T of the figure, the next measuring point 21 or Therefore, the movement to the detection tool T can be performed intuitively and easily. Therefore, the learning of the operation which has been required conventionally becomes unnecessary.

The movement mark T is linked with the movement of the stage 1.
(A) and (b) of FIG.
As illustrated in (c), the approaching process can be expressed. This allows quick and accurate movement.

Further, when the next measurement position is displayed on the monitor screen, the detection position of the detection tool is displayed at the position (measurement point) to be measured by an X mark or another form as shown in FIGS. it can.

12 to 14 show a situation in which the detection tools R and S follow the movement of the measuring point 21 (or the work 6 on the stage 1).

As shown in FIGS. 12 to 14, when the detection tools R, S and the workpiece 6 (that is, the measurement point 21) on the stage 1 are moved together with the movement of the X, Y stage 1, the monitor screen is displayed. Easy to measure accurately anywhere. This makes it possible to automatically detect when the measurement point enters the monitor screen. Even if the image moves in the monitor screen, the detection position follows, so that the same measurement result is always obtained. Also, if you look at the detection tool, you can see where and how you are measuring. It is not necessary to move the measurement point to the center of the monitor screen, and the operator can visually check the measurement point, so that the measurement position is not mistaken.

FIG. 21 shows a flow chart for creating an operation flow for creating a measurement procedure.
Shows a flowchart when measuring based on the measurement procedure created in FIG.

With reference to FIGS. 21 to 22, an outline of the preparation of the measuring procedure in the above-described measuring apparatus and the measuring operation performed based on the measuring procedure will be described.

First, in FIG. 21, the operator sets a desired number of measurement points on the drawing and then starts teaching the reference work 6 with reference to the drawing. The operator moves the reference work 6 to the stage 1 of the measuring device.
(FIG. 1). After that, the operator sets the origin on the reference work 6. In the example of FIG. 2, the center points O1 and O2 of the two small holes 6a and 6b of the reference work are measured,
With these, the origin of the reference work 6 is set. continue,
The operator manually moves the stage 1 in the x direction and the y direction, and displays the location on the reference work corresponding to the measurement point on the monitor screen 16 in the order set in advance on the drawing.

The operator manually moves the stage 1 so that the location of the measurement point moves to the monitor image.

Using the mouse 13, the best type of the detection tools R, S on the monitor screen 16 for the location on the reference work corresponding to the measurement point (eg, 21 shown in FIG. 3).
Set. Then, as shown in FIG.
And / or S are displayed in the monitor screen 16. At this time, the detection tool can be set at any position on the monitor screen 16. If the location where the detection tool is displayed is correct and the start point R1 and the end point R2 are appropriate, the position of the detection tool is determined. When the position of the detection tool is determined, the data is stored in the arithmetic processing unit 18.

At the time of measurement, the mouse 13 is used to perform a plurality of scans in the vicinity of the measurement point 21 (for example, in the directions of the arrows Ra and Rb), so that the measurement device performs image processing to measure the measurement point of the workpiece. 21 recognizes the contour, that is, the posture, and calculates a scanning direction that is close to a right angle to the direction of the edge W, and based on that, automatically detects the position of the detection tool in the direction perpendicular to or close to the direction of the edge W. Remember.

In addition, the detection of the edge W by the detection tool is always performed by scanning in the direction from the one with less unevenness of light and dark to the one with more unevenness.

Further, the operator designates the shape to be measured (circle, distance, width, etc.) and detects (measures) as many as necessary for shape calculation. Then, the measuring device automatically calculates the center and diameter of the circle using the coordinates of the edge.

FIG. 10 shows the detection points of such various shapes by X marks. Arrows indicate the scanning direction.

Further, the operator specifies the dimensional tolerance as needed.

The same measurement work is performed for each measurement point of the actual reference work corresponding to the other measurement points preset on the drawing for the reference work, and the position of the detection tool is sequentially input.

In this way, when the operator finishes inputting the positions of the detection tools corresponding to all the measurement points on the reference work, the operator confirms the positions and saves the measurement procedure up to that point in a file. As a result, the teaching based on the reference work is completed.

The measuring operation of the workpiece 6 to be measured will be described with reference to FIG.

First, the operator specifies the measurement procedure file on the measuring device according to the workpiece 6 to be measured. Next, the worker arranges the workpiece 6 to be measured on the stage 1 and sets the origin like the reference workpiece. At that time, even if the reference work and the work to be measured are arranged at different positions on the stage 1, that is, at positions slightly deviated from each other, the measuring device automatically calculates the positional deviation based on the origin positions of the two. .
Therefore, the operator only has to set the work 6 to be measured on the stage 1 without performing the alignment operation and without worrying about the displacement of the installation position.

When the origin setting of the work 6 to be measured is completed, the operator starts the execution of the measurement procedure file.

When the measurement point or the detection tool therefor is not displayed on the monitor screen 16, FIG.
(B) As shown in (c), a moving mark T of an arrow is displayed on the monitor screen 16. While looking at the direction and length of the movement mark T, the operator manually moves the stage 1 in the x direction and the y direction toward the measurement point in order.

When the measuring point 21 or the detection tools R and S therefor enter the monitor screen 16, the detection tools R and S previously stored based on the reference work 6 or the data of the drawing are automatically displayed on the monitor screen. To be done. At the same time, the movement mark T disappears from the monitor screen 16.

If the rectangular detection tool S and / or the detection tool R in the shape of an arrow are displayed on the monitor screen 16, the detection tool can be properly measured regardless of where the detection tool is located on the monitor screen 16. it can. If the positions of the start point and the end point of the detection tool are appropriate on the work, the point at which the tool portion of the detection tool R of the arrow or the detection tool S of the rectangle intersects the boundary W of the work is determined as the measurement point 21. When the measurement point 21 is determined, the coordinate data of the measurement point 21 is stored in the arithmetic processing unit 18.

When the operator determines that it is preferable to change the detection condition or the detection position during the measurement, the detection condition or the detection position is changed. For example, the X stage 1 or the Y stage 2 is moved, or the mouse 13 is used to change the type or position of the detection tool.

Further, by again performing a plurality of scans near the measurement point 21 (for example, in the directions of the arrows Ra and Rb),
The measuring device uses the image processing to measure the measuring point 2 of the workpiece to be measured.
The contour near 1 is recognized, that is, the posture is recognized, the scanning direction close to the direction of the edge W is calculated, and the detection tool Rc is automatically set in the direction perpendicular to or close to the direction of the edge W based on the calculated scanning direction. Set and measure.

Further, as shown in FIG. 10, the operator designates the shape (circle, distance, width, etc.) to be measured, and performs the measurement as many as necessary for the shape calculation. Then, the measuring device automatically calculates the center and diameter of the circle using the coordinates of the edge.

The same measurement work is sequentially performed on the positions of the actual detection tools corresponding to all the measurement points on the work to be measured.

In this way, when the operator finishes measuring all the measurement points on the workpiece to be measured, he or she confirms them and then
Save the previous measurement results to a file. If necessary, the number of measurement points that have failed in the tolerance determination is displayed on the monitor screen. Thus, the measurement operation ends.

The pre-teaching function is effective when the coordinate values of the measurement points are known. In this case, the teaching function means to create and store the measurement procedure, and the operator creates the procedure while searching for the next measurement point position. The pre-teaching function supports the teaching work, and the function can be used by inputting the coordinate values of multiple measurement points or the coordinate values (x, y) of the next measurement point in advance from the keyboard. The purpose is to save the trouble of finding a measurement point. For example, from the coordinate value input of the measurement point for pre-teaching, the coordinate value of the next measurement point is circle (x1, y1), width (x2, y2), corner (x3, y).
In case of 3), the teaching measurement procedure is created as a circle measurement procedure, a width measurement procedure, and a corner creation procedure.

By inputting the coordinate values (keyboard input values, CAD data, etc.) of the measurement points in this way, the direction and distance (difference in coordinate values) to the measurement points can be expressed by numerical values or figures (arrow marks, etc.). By showing, the measurement point can be searched accurately and quickly even with a high magnification (narrow field of view). In addition, operability is further improved by inputting a plurality of measurement point coordinates collectively.

By inputting the coordinate value of an arbitrary point, this function can be used without the purpose of measurement.

When the same procedure is performed based on the measurement procedure stored in advance, when it is clear that detection is difficult due to the real-time detection function, etc., a detection tool (for circle measurement, width measurement, point measurement, etc.) By making it possible to change the type, position, illumination condition, and detection condition on the spot, the measurement work can be performed smoothly and reliably.

The present invention is not limited to the above embodiments.
For example, in another embodiment of the present invention, the measurement point 21 or the detection tool R, S therefor is located at a predetermined distance outside the monitor screen 16 (10% to 0% of the size of the monitor screen 16) or a predetermined distance inside the monitor screen 16 (10% to 0%). 50% to 0 of the size of the monitor screen 16
%), The detection tools R and S stored in advance based on the data of the reference work 6 or the drawing are automatically displayed on the monitor screen, and at the same time, the movement mark T disappears from the monitor screen 16. The moving mark can adopt not only an arrow shape but also various other shapes. FIG. 23 shows an example. The direction of movement is not limited to the arrow, but it is possible to adopt a blinking shape or change the color. The movement distance is expressed not only in length, but also in thickness and shape,
It is also possible to indicate it by a numerical value.

[Brief description of drawings]

FIG. 1 schematically shows an example of a measuring device for carrying out the present invention.

FIG. 2 shows a lead frame (an example of a work to be measured) installed on a stage.

FIG. 3 shows an example in which a plurality of locations where dimensions need to be strictly controlled are set as measurement points in an example of a monitor image.

FIG. 4 corresponds to the monitor image of FIG. 3 and shows a measurement order of a plurality of places where dimensions need to be strictly controlled.

FIG. 5 shows an example in which the detection tool used in the present invention is a line tool. (A) shows an example of miss detection, and (B) shows an example of correct detection.

FIG. 6 shows an example in which the detection tool used in the present invention is an area tool. (A) shows an example of miss detection, and (B) shows an example of correct detection.

FIG. 7 (A) recognizes a contour near a measurement point of a workpiece to be measured by performing a plurality of scans with an arrow-shaped detection tool or a tool portion thereof, and based on the recognition, an edge direction is detected. An example of a situation in which a detection tool is automatically set in the vertical direction or a direction close to the vertical direction is shown. (B) shows an example of a situation in which the detection tool is set in a direction perpendicular to the direction of the edge of the work to be measured or a direction close to the direction to perform measurement.

FIG. 8 shows an example of a situation in which an edge is detected by a detection tool by scanning in a direction from dark to light.

9A shows an example of a light-dark level when scanning is performed from the lower left position to the upper right position in FIG.
FIG. 8B shows an example of the brightness level when scanning from the upper right position to the lower left position in FIG.

FIG. 10 shows detection positions of various shapes by X marks.

FIGS. 11A, 11B, and 11C show a process in which a monitor image moves toward a measurement point by moving a stage. In any of (a), (b) and (c), the next measurement point is not within the display range of the monitor screen. When the next measurement point enters a predetermined distance from the edge of the monitor screen, the movement mark automatically disappears from the monitor image. At the same time, the detection tool is displayed on the monitor screen.

FIG. 12 illustrates an example of a relationship between a measurement point of a workpiece to be measured and a detection tool in a monitor image.

FIG. 13 illustrates a situation in which the relative relationship between the measurement point of the workpiece to be measured and the detection tool moves in the monitor image without changing from the relative relationship in FIG. That is, this shows a situation in which the detection tool follows the movement of the work on the measurement point and the stage.

FIG. 14 is a diagram showing the relative relationship between the measurement point of the workpiece to be measured and the detection tool unchanged from the relative relationship shown in FIGS. 12 and 13;
This shows a situation where the user moves further in the monitor image.

FIG. 15 shows an example of a relationship between a moving mark in a monitor image and a measurement point of a workpiece to be measured outside the monitor image.

FIG. 16 shows a measurement point of a workpiece to be measured outside the monitor image and a detection tool in the monitor image when the monitor image moves toward the measurement point from the state of FIG. 15 by moving the stage. 1 shows an example of the display relationship. The next measurement point is not on the monitor screen but is approaching it.

FIG. 17 is a measurement point of a work to be measured outside the monitor image and a detection tool in the monitor image when the monitor image moves from the state of FIG. 16 toward the measurement point by further moving the stage. An example of the display relationship with is shown. The next measurement point is on the monitor screen.

FIG. 18 shows another example of the relationship between the measurement point of the work to be measured and the detection tool in the monitor image when dust is present near the measurement point of the work to be measured. In this state, correct measurement is possible.

FIG. 19 shows the relationship between the measurement point of the work to be measured in the monitor image and the detection tool in another state where dust is present near the measurement point of the work to be measured. In this state, correct measurement is impossible.

FIG. 20 shows the position of the detection tool in order to change the relationship between the measurement point of the work to be measured and the detection tool in the monitor image in the state where dust is present near the measurement point of the work to be measured in FIG. Three methods for shifting are schematically shown.

FIG. 21 is a flowchart for creating an operation flow for creating a measurement procedure.

FIG. 22 is a flowchart when measuring based on the measurement procedure created in FIG. 21;

FIG. 23 shows examples of various moving marks.

[Explanation of symbols]

 1 X stage 2 Y stage 3 X moving handle 4 Y moving handle 5 XY counter 6 Work (reference work, work to be measured) 6a, 6b Small hole 7 Microscope body 8 Eyepiece 9 CCD camera 10 Host computer 11 Image processing Device 12 Foot switch 13 Mouse 15 Monitor device 21 to 32 Measuring point D Dark area L Bright area M Dust O Center P Center area R Detection tool S Detection tool T Move mark W Edge

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazuhisa Nomura 75-1, Hasunumacho, Itabashi-ku, Tokyo Inside Topcon Co., Ltd.

Claims (7)

[Claims] 1. In a measuring method for measuring a workpiece to be measured in comparison with prestored data, when a detection tool detects an edge, a plurality of edges of the detection tool are oriented toward the periphery. A method for measuring minute dimensions, characterized in that any one of the tool parts is selected, and scanning is performed from the central region of the detection tool toward the periphery to detect edges. 2. When the edge of the work to be measured is detected by the detection tool, the relative position of the detection tool is moved with respect to the work to be measured, and when the central area of the detection tool crosses the edge, scanning of the tool portion is performed. The measuring method according to claim 1, wherein the directions are opposite. 3. The minimum size of the central area of the detection tool corresponds to three or more pixels.
Measurement method described in 1. 4. The measurement according to claim 1, wherein the detection of the edge by the detection tool is performed by scanning after converting from the direction with less unevenness of light and dark to the direction with more unevenness. Method. 5. The measuring method according to claim 1, wherein the detection tool is a line tool, and the scanning direction is indicated by an arrow. 6. The detection tool is a rectangular area tool, and includes four cross-shaped tool portions facing from the central region of the detection tool to the periphery, and the size and shape of the detection tool are variable. The measuring method according to any one of claims 1 to 4. 7. The detection tool is a rectangular area tool, and has four cross-shaped tool portions facing four sides from the central area of the detection tool and four diagonals from the central area of the detection tool. The measuring method according to any one of claims 1 to 4, wherein the measuring tool includes four X-shaped tool portions, and the size and shape of the detection tool are variable.