JP3510359B2 - Optical measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a magnifying optical system suitable for use in an optical microscope, an autofocus system and an edge detector, and the shape formed by the edge of a measuring object and its height in the optical axis direction. The present invention relates to an optical measuring device that automatically takes in coordinate values of the height and performs measurements.

[0002]

2. Description of the Related Art Conventionally, as an optical measuring device, an object to be measured is placed on a stage like a measuring microscope, and measurement points such as edges of the object to be measured are measured by an eyepiece lens or an imaging device through an enlarging optical system. A method is widely used in which a stage is moved while magnifying and observing and the shape of an object to be measured is measured from the amount of movement.

In such an optical measuring device, when a person performs the work of aligning the measurement point with the edge of the object to be measured, a difference occurs due to individual error of the operator or a difference in measurement time, and the difference occurs. There is an inconvenience that the measurement requires a huge amount of time and labor.

Therefore, in order to avoid such inconvenience, an edge detector has been developed which outputs an edge signal when the measurement point coincides with the edge. This edge detector irradiates the measurement object with light, determines whether the edge of the measurement object passes through the measurement point from the change in the reflected light or the transmitted light, and outputs the edge signal. The stage coordinates are read when an edge signal is output from the edge detection device during measurement. Further, by further providing an autofocus system, the measurement point of the measurement object is focused, and the height of the measurement point can be obtained from the movement amount of the magnifying optical system at this time.

In this manner, by providing the optical measuring device with the edge detector and the autofocus system, the shape and height formed by the edge can be measured with less individual error.
It can be done efficiently.

FIG. 7 shows an example of a conventional optical measuring device. In the figure, reference numeral 1 denotes a stage, on which a measurement object 3 is placed, and the measurement object 3 is illuminated by a transmitted light source 4.

The illumination light transmitted through the measurement point 5 of the object 3 to be measured is collimated by the objective lens 2 and condensed by the condenser lens 8. A pinhole 9 is arranged at the focus position on the upper side of the condenser lens 8, and the light transmitted through the pinhole 9 is received by the light receiving element 10. The light receiving element 10 outputs an electric signal proportional to the intensity of the light transmitted through the pinhole 9, and supplies this electric signal to the edge detection unit 30.

The edge detector 30 amplifies the electric signal from the light receiving element 10 and converts it into a pulse signal with a predetermined value Vth as a threshold value to generate an edge signal I. On the other hand, the stage 1 is moved in the direction perpendicular to the optical axis of the objective lens 2 by driving the stage motor 20 via the stage drive circuit 34 according to an instruction from the host computer 40.
The amount of movement of the stage 1 is based on an electric signal output from the stage scale 21 and is based on the stage movement counter 3
It can be obtained by counting at 5. Then, the stage movement amount counter 35 outputs the stage movement amount at that time to the host computer 40 at the rising or falling timing of the edge signal I. Further, the objective lens 2 is movable in the optical axis direction by driving the Z-axis motor 18 via the Z-axis drive circuit 32.

As a result, the relative distance between the stage 1 and the objective lens 2 can be changed, and the amount of movement of the objective lens 2 is determined by the Z-axis movement amount counter 33 based on the electric signal from the Z-axis scale 19. It can be obtained by counting with.

The probe light 17 output from the laser diode 11 is focused on the measuring point 5 of the measuring object 3 through the lens 15, the half mirror 6 and the objective lens 2 and reflected by the measuring object 3. After passing through the objective lens 2 and the half mirror 7, the light 17 is converged by the condenser lens 16 and separated into two directions by the half mirror 14. Then, the probe light reflected by the half mirror 14 is incident on the light receiving element 12a through a pinhole 13a provided in front of the focal plane of the condenser lens 16,
Further, the other probe light transmitted through the half mirror 14 passes through the pinhole 13b behind the focal plane,
It is incident on the light receiving element 12b.

The outputs from the light receiving elements 12a and 12b are sent to a focus detecting section 31. At the focus detecting section 31, a focus signal is obtained from the difference between the output of the light receiving element 12a and the output of the light receiving element 12b. A feedback signal H for driving the Z axis is generated from this focus signal.

This feedback signal H is input to the Z-axis drive circuit 32 and drives the Z-axis motor 18 to drive the objective lens 2
Moves in the optical axis direction. This constitutes an autofocus system in which the distance between the measurement point 5 and the objective lens 2 is always kept constant.

The focus signal J output from the focus detection unit 31 is generated as a pulse signal when the absolute value of the focus signal becomes a predetermined value p or less and is given to the Z-axis movement amount counter 33. To be When the focus signal J is input, the Z-axis movement amount counter 33 outputs the Z-axis movement amount at that time to the host computer 40.

The focus detection section 31 is controlled by the autofocus control signal K output from the host computer 40.
The focus detection unit 31 does not output the feedback signal H and the focus signal J when the focus detection unit 31 is off, and stops driving the objective lens 2.

In the optical measurement with such a configuration, first, the stage 1 is moved via the stage drive circuit 34 with the focus detection unit 31 turned off, so that the stage movement amount counter 35 is operated. By taking in the coordinates of the edge of the measurement object 3, turning on the focus detection unit 31 to enable the autofocus system, and moving the stage 1 to align the measurement point 5 with the position where the height is measured, Height information can be fetched from the Z-axis movement amount counter 33.

On the other hand, as an optical measuring instrument of this type, there is one disclosed in Japanese Patent Publication No. 4-26685. This optical measuring instrument uses an autofocus system that delays the focus signal to generate a feedback signal and drives the Z axis. An edge determination circuit that outputs an edge signal when the absolute value of the focus signal exceeds a predetermined value is provided.

Therefore, also in this method, the shape can be measured by using the edge signal, and by keeping the distance between the magnifying optical system and the measuring point of the measuring object always constant,
The height can also be measured.

[0018]

However, in the optical measuring device shown in FIG. 7, when the distance between the magnifying optical system and the stage is changed during edge detection, the reflected light to the edge detecting section 30 or The transmitted light changes,
The edge cannot be detected correctly. Further, the output of the photodetection unit 30 of the autofocus system becomes unstable at the edge position. For this reason, since the normal autofocus system is not operated at the edge position, the autofocus system cannot be used during edge detection. This means that the position of the edge of the measuring object and the measurement in the height direction cannot be measured at the same time, and the same place must be scanned twice and measured separately, which requires a great deal of time and effort. In addition to that, there is a problem that the operation of the operator becomes complicated.

Further, in Japanese Patent Publication No. 4-26685,
Since the edge is detected while operating the autofocus system, the edge can be detected while using the autofocus system. However, since the Z-axis is driven by using the feedback signal obtained by delaying the focus signal, there is a problem that it is not possible to quickly follow the autofocus and it takes a long time for the measurement.

The present invention has been made in view of the above circumstances, and it is possible to easily and quickly measure the position or length formed at the edge of the object to be measured and the height by a single scan. It is an object of the present invention to provide an optical measuring device capable of performing the above.

[0021]

According to the present invention, there is provided a stage on which an object to be measured is placed, a magnifying optical system which is movable relative to the stage in a direction perpendicular to the optical axis, and the magnifying optical system. An edge detection unit that detects an edge signal corresponding to an edge portion of the measurement object from a change in transmitted light or reflected light with respect to the measurement object that is relatively moved,
Focus detection means for detecting a focus signal required to keep the relative distance between the measurement point of the measurement object and the magnifying optical system constant, and the stage and the stage based on the focus signal from the focus detection means. Autofocus means for controlling the relative distance of the magnifying optical system in the optical axis direction to keep the relative distance between the measuring point of the measuring object and the magnifying optical system constant, an edge signal from the edge detecting means, and the combination The edge detection means and the control means for controlling the validity or invalidity of the focus detection means by a focus signal from the focus detection means, and the focus signal of the focus detection means validated by the control means. In addition to measuring the height of the measurement object in the optical axis direction, the position or length formed by the edge is measured by the edge signal of the edge detecting means.

Further, in the present invention, the control means controls the focus detection means to be effective and the edge detection means to be ineffective by the edge signal, and the edge detection means is effective and is made to be effective in accordance with the focus signal. The focus detecting means is controlled to be invalid. Further, in the present invention, the autofocus means is of a confocal type autofocus system.

[0023]

As a result, according to the present invention, the magnifying optical system is provided so as to be relatively movable in the direction perpendicular to the optical axis with respect to the stage on which the measuring object is placed, and the magnifying optical system is moved relative to the magnifying optical system. The edge detection means detects an edge signal corresponding to the edge portion of the measurement object from the change of transmitted light or reflected light with respect to the measurement object, and keeps the relative distance between the measurement point of the measurement object and the magnifying optical system constant. The focus detection means detects the focus signal required for the, and the focus signal of this focus detection means controls the relative distance in the optical axis direction between the stage and the magnifying optical system to magnify the measurement point of the object to be measured. The relative distance to the optical system is kept constant by the autofocus means, and the edge detection means and the focus detection means are enabled or disabled by the edge signal detected by the edge detection means and the focus signal detected by the focus detection means. The height of the object to be measured in the optical axis direction can be measured from the focus signal controlled by this control, and the position or length formed by the edge can be measured by the edge signal of the edge detecting means. By doing so, it becomes possible to obtain all of these measurement results with one scan.

Further, according to the present invention, the control means controls the focus detecting means to be effective and the edge detecting means to be invalid by the edge signal, and the edge detecting means is effective and the focus detecting means is invalid to be made by the focus signal. Since the focus detection means is enabled only by the edge signal by controlling to 1, it is possible to prevent the autofocus means from operating unnecessarily in a portion where there is no measurement object in which the edge signal is not detected.

Further, according to the present invention, since the autofocus means is constituted by the confocal type autofocus system, the distance required to keep the relative distance between the measuring point of the measuring object and the magnifying optical system constant. A corresponding focus signal can be obtained with high accuracy.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 shows a schematic configuration of the first embodiment, and the same parts as those in FIG. 7 are designated by the same reference numerals.

In the first embodiment, edge detection and
A focus detection control unit 36 is provided. The edge detection / focus detection control unit 36 receives the edge signal I from the edge detection unit 30 and the focus signal J from the focus detection unit 31, and outputs the edge detection unit control signal L and the autofocus control signal K. I am trying to output.

The edge signal control signal L here is a signal for switching on / off of the edge detecting section 30, and the edge detecting section 30 does not change the edge signal when it is off. The autofocus control signal K is a signal for switching on / off of the focus detection unit 31, and when the focus detection unit 31 is off, the feedback signal H and the focus signal J are not output, and the objective lens 2 I'm trying to stop.

On the other hand, the object 3 to be measured is placed on the stage 1 and illuminated by the transmitted light source 4. Then, the objective lens 2 and the condenser lens 8 constitute a magnifying optical system.

The illumination light transmitted through the measuring point 5 of the measuring object 3 becomes a parallel light flux by the objective lens 2, and the condenser lens 8
Is collected by. This light is incident on the edge detector including the pinhole 9, the light receiving element 10, and the edge detection unit 30.

The pinhole 9 is arranged at the focus position above the condenser lens 8, and the light receiving element 10 receives the light transmitted through the pinhole 9 and outputs an electric signal proportional to its intensity. ing.

The edge detecting section 30 amplifies the electric signal from the light receiving element 10 and converts it into a pulse signal with a predetermined value Vth as a threshold value to generate an edge signal I. The stage 1 includes the stage drive circuit 34 and the stage motor 2
The vertical movement mechanism composed of 0 enables movement in the direction perpendicular to the optical axis. That is, by driving the stage motor 20 via the stage drive circuit 34 according to an instruction from the host computer 40, the stage 1 can be moved in the direction perpendicular to the optical axis of the objective lens 2 via the vertical movement mechanism. There is.

The moving amount of the stage 1 is measured by a vertical length measuring device including a stage scale 21 and a stage moving amount counter 35, and an electric signal output from the stage scale 21 is counted by the stage moving amount counter 35. It can be obtained.

The stage movement amount counter 35
Outputs the stage movement amount at that time to the host computer 40 at the rising or falling timing of the edge signal I.

The Z-axis drive circuit 32 and the Z-axis motor 18 constitute a Z-axis direction drive mechanism, and the Z-axis scale 19 and the Z-axis drive amount counter 35 constitute a Z-axis direction length measuring device.

The objective lens 2 is movable in the optical axis direction by driving the Z-axis motor 18 by the Z-axis drive circuit 32 constituting the Z-axis direction drive mechanism, and the stage 1 and the objective lens 2 are moved. It allows to change the relative distance between. Further, the amount of movement of the objective lens 2 is obtained by counting an electrical signal from the Z-axis scale 19 which constitutes the Z-axis direction length measuring device by the Z-axis movement amount counter 33.

On the other hand, the laser diode 11 and the lens 1
5, condensing lens 16, half mirror 14, pinhole 1
A confocal autofocus system is configured by 3a and 13b, the light receiving elements 12a and 12b, and the focus detection unit 31.

In this case, the probe light 17 output from the laser diode 11 is focused on the measuring point 5 via the lens 15, the half mirror 6 and the objective lens 2. In addition, the probe light 17 reflected by the measurement object 3 passes through the objective lens 2 and the half mirror 7, and then the condenser lens 16
Is converted into convergent light by the half mirror 14 and separated into two directions by the half mirror 14.

The probe light reflected by the half mirror 14 is incident on the light receiving element 12a through the pinhole 13a provided in front of the focal plane of the condenser lens 16, and is transmitted through the half mirror 14 on the other side. Probe light passes through the pinhole 13b behind the focal plane and enters the light receiving element 12b.

Outputs from the light receiving elements 12a and 12b are sent to a focus detecting section 31, which then detects the focus.
A focus signal is obtained from the difference between the output of the light receiving element 12a and the output of the light receiving element 12b, and a feedback signal H for driving the Z axis is generated from this focus signal.

This feedback signal H is input to the Z-axis drive circuit 32, and the Z-axis motor 18 is driven to drive the objective lens 2
Moves in the optical axis direction. This constitutes an autofocus system in which the distance between the measurement point 5 and the objective lens 2 is always kept constant.

Further, the focus detection section 31 determines that the focus signal is in focus when the absolute value of the focus signal becomes equal to or less than a specific value p, and generates a focus signal J. When the focus signal J is input to the Z-axis movement amount counter 33, the Z-axis movement amount at that time is output to the host computer 40.

Then, the edge signal I of the edge detector 30
The focus signal J of the focus detection unit 31 is input to the edge detection / focus detection control unit 36. In this case, when the edge detection / focus detection control unit 36 detects the trailing edge of the edge signal I, the edge detection unit control signal L causes the edge detection unit 3 to operate.
0 is turned off and the autofocus control signal K
The focus detection unit 31 is turned on by. Also, the focus signal J
Conversely, the focus detection unit 31 is turned off by the autofocus control signal K, and the edge detection unit 30 is turned on by the edge detection unit control signal L.

However, in such a structure, for example, as shown in FIG. 2, as a measurement object 3 which is discontinuous and has a flat surface, the length between the edges of the lead portion of the lead frame and the height of the lead portion are increased. Regarding this, an operation in the case of performing measurement while moving the stage 1 to the left in the drawing will be described.

Here, FIG. 3 shows the relationship among the output of the light receiving element 10, the edge signal I, the focus signal and the focus signal J. Now, when the transmitted illumination light is incident on the objective lens 2 as shown in FIG. 2, the edge detector 30 is turned on,
The focus detection unit 31 is off. From this state, by moving the stage 1 to the left in the drawing, the measurement target 3
When the point a in FIG. 3 crosses the measurement point 5, the transmitted illumination light is blocked, so that the output from the light receiving element 10 becomes small as shown in FIG. When this output becomes smaller than Vth, the edge signal I falls as shown in FIG. When the edge signal I falls, the stage movement amount counter 35 is latched, the coordinates corresponding to the point a are output, and are taken into the host computer 40.

At the same time, the edge detection / focus detection control unit 36
Is detected by the fall of the edge signal I.
Is turned off and the focus detection unit 31 is turned on. Focus detection unit 31
Is turned on, the feedback signal H is output to the Z-axis drive circuit 32, and the objective lens 2 is moved via the motor 18, whereby the focus signal shown in FIG.
The difference signal between 2a and 12b is changed. Then, when the absolute value of this focus signal becomes equal to or less than p, a focusing signal J shown in FIG. 3D is generated, and the Z axis movement amount at that time is caused by the falling of the pulse of this focusing signal J. Movement counter 33
Are latched by and are taken into the host computer 40.

As a result, the height of the measuring object 3 is measured between the points a and b from the reference position. Further, the edge detection / focus detection control unit 36 turns off the focus detection unit 31 and turns on the edge detector 30 when the pulse of the focus signal J falls.

Next, when the point b crosses the measurement point 5, the transmitted illumination light comes into the objective lens 2, so that FIG.
As shown in (a), the output of the light receiving element 10 becomes large.
Then, when the output of the light receiving element 10 exceeds Vth, the edge signal I rises as shown in FIG. 7B, and the stage movement amount at that time, that is, the coordinates of the point b is latched and taken into the host computer 40.

By such an operation, a
It becomes possible to measure the distance from the edge of the point to the edge of the point b and the height between them by one scanning, and in the same way, the distance and height from the edge of the point c to the edge of the point d You will be able to measure.

In this case, since the focus detector 31 is turned on only when the edge signal I falls, the autofocus system does not operate when the object 3 to be measured does not exist, and the objective The useless movement of the lens 2 is prevented.

Therefore, according to such a first embodiment,
The objective lens 2 is arranged so as to be relatively movable in a direction perpendicular to the optical axis with respect to the stage 1 on which the measuring object 3 is mounted, and the change of transmitted light with respect to the measuring object 3 which is moved relative to the objective lens 2. The edge detection unit 30 detects an edge signal I corresponding to the edge portion of the measurement target 3 from the measurement target, and controls the relative distance between the stage 1 and the objective lens 2 in the optical axis direction to measure the measurement point of the measurement target 3. The relative distance between the objective lens 2 and the objective lens 2 is kept constant by an autofocus system, and the measurement point 5 of the measuring object 3 and the objective lens 2 are maintained by this autofocus system.
An edge signal detected by the edge detection / focus detection control section 36 by the focus detection section 31 and a focus signal J corresponding to the distance required to keep the relative distance from the edge detection section 30 constant. The edge detection unit 30 is turned off and the focus detection unit 31 is turned on by the fall of I, and the focus detection unit 31 is turned off and the edge detection unit 30 is turned on by the focus signal J. Focusing signal J that is validated by this control
Since the height of the measuring object 3 in the optical axis direction and the position or length formed by the edge by the edge signal I of the edge detecting unit 30 are measured respectively,
All the measurement results can be obtained by scanning once, and the measurement work can be easily and quickly performed, and the distance and height can be easily associated with each other at the same location.

Further, since the focus detection section 31 is turned on at the timing of the fall of the edge signal I, the autofocus system becomes unnecessary in the place where there is no measurement object 3 in which the edge signal I is not detected. Since it does not operate, it is possible to prevent unnecessary movement of the objective lens 2. (Second Embodiment) FIG. 4 shows a schematic configuration of the second embodiment. The same parts as those in FIG. 1 are designated by the same reference numerals.

In this case, in FIG. 4, a reflective light source 22 is used instead of the transmissive light source 4 shown in FIG. The light emitted from the transmissive light source 22 is reflected by the half mirror 23 and focused on the measurement point 5 via the objective lens 2. Then, the reflected light from the measurement object 3 passes through the objective lens 2 and the condenser lens 8, and then enters the light receiving element 10 through the pinhole 9 arranged at the focal position on the upper side of the condenser lens. .

In this case, since the pinhole 9 is at the focal point on the upper side of the condenser lens 8, the output of the light receiving element 10 becomes the maximum when the measurement point 5 coincides with the surface of the measuring object 3. In addition, the edge detection unit 30 amplifies the electric signal from the light receiving element 10, and when the signal becomes smaller than the predetermined value Vth, generates the negative pulse edge signal I. The stage movement amount counter 35 outputs the stage movement amount at that time to the host computer 40 at the falling timing of the edge signal I.

In such a structure, for example, as shown in FIG. 5, for the measuring object 3 having a flat surface and a step, the length and the height between the edges of the measuring object 3 are shown in the left direction of the stage 1 in the figure. The operation when measuring while moving to will be described.

Here, FIG. 6 shows the relationship among the output of the light receiving element 10, the edge signal I, the focus signal and the focus signal J. First, in the state of FIG.
0 is on, and the focus detection unit 31 is off. When the point a of the measuring object 3 crosses the measurement point 5 by moving the stage 1 to the left in the figure from this state, the measurement point 5
Is below the surface of the object 3 to be measured, the reflected light is not condensed by the pinhole 9, and the output of the light receiving element 10 becomes small as shown in FIG. 6A. At this time, the light receiving element 10
Is smaller than Vth, a negative pulse of the edge signal I is output as shown in FIG. When the edge signal I falls, the stage movement amount counter 35 outputs the coordinates corresponding to the point a, and the coordinates are taken into the host computer 40.

At the same time, the edge detection / focus detection control unit 36
Turns off the edge detection unit 30 and turns on the focus detection unit 31 when the edge signal falls. Focus detection unit 31
When is turned on, the feedback signal H is output to the Z-axis drive circuit 32 and the objective lens 2 is moved via the motor 18, whereby the focus signal shown in FIG.
The difference signal between 2a and 12b is changed. Then, when the absolute value of this focus signal becomes equal to or less than p, a focusing signal J shown in (d) of FIG. Movement counter 33
Are latched by and are taken into the host computer 40.

As a result, the height of the measuring object 3 between the points a and b is measured. In addition, the edge detection / focus detection control unit 36 causes the pulse of the focus signal J to fall,
The focus detection unit 31 is turned off and the edge detector is turned on.

At this time, the measuring point 5 coincides with the surface of the object 3 to be measured, as shown in FIG. 6B, so that the output of the light receiving element 10 becomes large again. Next, when the point b crosses the measurement point 5, the measurement point 5 is below the surface of the measurement object 3 as in the case of the point a described above. Therefore, the output of the light receiving element 10 becomes small again, and the negative pulse of the edge signal I is output. Below, a
The same operation as in the case of dots is repeated.

By such an operation, it becomes possible to measure the distance from the edge of the point a to the edge of the point b and the height of the edges of the points a and b at the same time. Therefore, according to the second embodiment, by using the reflection light source 22, the height of the measurement target 3 in the optical axis direction can be reduced even if the measurement target 3 has a stepped shape. The position or the length formed by the edge can be easily and quickly obtained by the measurement by one scanning.

In the first and second embodiments described above, the edge signal I and the focus signal J are input to the edge detection / focus detection control unit 36, and the edge detection unit control signal L and the autofocus signal K are input. Edge detection / focus detection control unit 3
However, the edge signal I and the focus signal J are input to the host computer 40, and the edge detection unit control signal L and the autofocus signal K are output from the host computer 40. The host computer 40 plays the role of the detection / focus detection control unit 36.
Can also be done.

Although the stage 1 has only one degree of freedom, two-dimensional coordinates may be taken in by using an XY stage that can move in a plane perpendicular to the optical axis of the objective lens 2. . Further, the edge signal for latching the Z-axis movement amount counter 35 and the edge signal output to the edge detection / focus detection control unit 36 for controlling the focus detection unit 31 are separated, and different threshold values are used. It is also possible to stabilize the operation of the autofocus system near the edge by using. A slit can also be used for the pinhole 9 used for edge detection. Further, as the autofocus system, a confocal type autofocus system is used in the above-mentioned first and second embodiments.
The same effect can be obtained in an autofocus system using a method such as astigmatism or pupil division.

Although the description has been given based on the embodiments, the following inventions are included in the present specification. (1) A stage on which a measurement target is placed, a magnifying optical system that is movable relative to the stage in a direction perpendicular to the optical axis, and the measurement target that is moved relative to the magnifying optical system. Edge detection means for detecting an edge signal corresponding to the edge portion of the measurement object from the change of transmitted light or reflected light with respect to, and keeps a relative distance between the measurement point of the measurement object and the magnifying optical system constant. Focusing means for detecting a focusing signal required for measuring the object to be measured by controlling the relative distance between the stage and the magnifying optical system in the optical axis direction by the focusing signal from the focusing detection means. The auto focus means for keeping the relative distance between the point and the magnifying optical system constant, and the edge detection means and the focus detection hand by the edge signal from the edge detection means and the focus signal from the focus detection means. A control means for controlling the validity or invalidity of the measurement object, and measuring the height of the measuring object in the optical axis direction from the focus signal of the focus detection means made valid by the control means, and An optical measuring device characterized in that the position or length formed by the edge is measured by an edge signal of the edge detecting means.

By doing so, the position or length of the measurement object formed at the edge and the height can be measured simply and quickly by one scan. (2) In the optical measurement device according to (1), the control means controls the focus detection means to be valid and the edge detection means to be invalid by the edge signal, and the edge detection means is controlled by the focus signal. The focus detection means is controlled to be valid and invalid.

In this way, the focus detection means becomes effective only by the edge signal, so that it is possible to prevent the autofocus means from operating unnecessarily at a location where there is no measurement object whose edge signal is not detected. You can

(3) In the optical measuring device described in (1), the autofocus means is a confocal autofocus system. With this configuration, a focusing signal corresponding to the distance required to keep the relative distance between the measurement point of the measurement object and the magnifying optical system constant can be obtained with high accuracy.

[0067]

As described above, according to the present invention, it is possible to easily and quickly perform the position or length measurement and the height measurement formed at the edge of the measuring object and the height measurement by one scanning.
Moreover, it is possible to easily associate the distance and height at the same location.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a first embodiment of the present invention.

FIG. 2 is a diagram around a measurement point for explaining the first embodiment.

FIG. 3 is a signal waveform diagram of each part for explaining the first embodiment.

FIG. 4 is a diagram showing a schematic configuration of a second embodiment of the present invention.

FIG. 5 is a diagram around a measurement point for explaining a second embodiment.

FIG. 6 is a signal waveform diagram of each part for explaining the second embodiment.

FIG. 7 is a diagram showing a schematic configuration of a conventional optical measurement device.

[Explanation of symbols]

1 ... Stage, 2 ... Objective lens, 3 ... Object to be measured, 4 ...
Transmitted light source, 5 ... Measuring point, 6, 7 ... Half mirror, 9 ... Pinhole, 10 ... Light receiving element, 11 ... Laser diode,
12a, 12b ... Pinhole, 13a, 13b ... Light receiving element, 14 ... Half mirror, 17 ... Probe light, 18 ... Z
Axis motor, 19 ... Z-axis scale, 20 ... Stage motor, 21 ... Stage scale, 22 ... Transmitted light source, 30 ...
Edge detection unit, 31 ... Focus detection unit, 32 ... Z-axis drive circuit, 33 ... Z-axis movement amount counter, 34 ... Stage drive circuit, 35 ... Stage movement amount counter, 40 ... Host computer, I ... Edge signal, J ... focus signal, K ... autofocus control signal, L ... edge detection unit control signal.

─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A 63-128213 (JP, A) JP-A 1-199103 (JP, A) JP-A 1-245104 (JP, A) JP-A 2- 90117 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01B 11/00-11/30

Claims (3)

(57) [Claims] 1. A stage on which a measurement target is placed, a magnifying optical system provided so as to be relatively movable with respect to the stage in a direction perpendicular to an optical axis, and the measurement which is relatively moved with respect to the magnifying optical system. Edge detection means for detecting an edge signal corresponding to the edge portion of the measurement object from a change in transmitted light or reflected light with respect to the object, and a relative distance between the measurement point of the measurement object and the magnifying optical system is constant. Focus detection means for detecting a focus signal required to maintain the object to be measured by controlling the relative distance in the optical axis direction between the stage and the magnifying optical system by the focus signal from the focus detection means. Autofocus means for keeping the relative distance between the measurement point and the magnifying optical system constant, and the edge detection means and the edge signal from the edge signal from the edge detection means and the focus signal from the focus detection means. Control means for controlling the validity or invalidity of the focus detection means, and measuring the height of the measuring object in the optical axis direction from the focus signal of the focus detection means validated by the control means. At the same time, the optical measuring device is characterized in that the position or the length formed by the edge is measured by the edge signal of the edge detecting means. 2. The control unit controls the focus detection unit to be effective and the edge detection unit to be invalid by the edge signal, and the edge detection unit is effective and the focus detection unit to be activated by the focus signal. The optical measurement device according to claim 1, wherein the optical measurement device is disabled. 3. The optical measuring device according to claim 1, wherein the autofocus means is a confocal autofocus system.