JPH07111334B2 - Surface shape measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface shape measuring apparatus for measuring the shape of minute unevenness of an object to be measured by a light spot displacement method in a non-contact manner.

[0002]

2. Description of the Related Art To measure the surface state of an object in a non-contact manner by an optical method, (a) a method of measuring an image of reflected light from the surface of an object to be measured, such as a light section method,
(b) Detecting the scattering angle distribution or speckle pattern by utilizing light scattering, (c) Utilizing light wave interference,
(d) Critical angle method, (e) Light spot displacement method,
Are known. The above method (a) is suitable for measuring a relatively rough surface, but is not suitable for measuring a surface having a roughness of submicron or less. In addition, although (b) to (d) have considerably excellent resolution, the practical measurement range is on the order of a few microns, and when a higher resolution is required, the light spot of (e) is generally used. The displacement method is used.

This light spot displacement method is equipped with an optical system that allows a light beam to be obliquely incident on the surface of an object to be measured and receives the reflected light reflected by the surface. The reflection system is displaced according to the shape and position of the surface. The center position of the light spot of light is converted into an electric signal to detect the surface shape of the measured object, and the resolution is 0.0
Extremely high at 1 μm or less, and practical measurement range is 100 μm
The above is possible. Therefore, it is widely used as a material suitable for measuring the roughness of a polished surface, a cut surface, the surface of a semiconductor wafer, and the like, and for inspecting the shape of the cutting edge of a cutting tool, the tip of a diamond contact needle, and the like.

However, when the object to be measured is vibrating, the change in the output signal due to the vibration is superimposed on the change in the output signal according to the roughness and shape of the surface of the object to be measured, and both It is impossible to distinguish and extract only the output signal corresponding to the surface roughness and shape. For this reason, it cannot be used for the purpose of inspecting the surface condition of a work piece by incorporating it into a cutting process using a precision lathe or a mirror polishing process, for example, which is a major obstacle to automation of the precision processing process .

[0005]

The present invention pays attention to such a point, and in measurement by the light spot displacement method, disturbance such as vibration of the object to be measured can be removed to easily perform high precision measurement.
The task was to make it possible.

[0006]

In order to achieve the above object, according to the present invention, a small-diameter light spot and a large-diameter light spot are generated on the surface of an object to be measured by two kinds of light rays, The surface shape of the object to be measured is detected using the output signal of the reflected light. The above two light spots can be separated by two independent optical systems, or
Can be produced by a single optical system.

Further, two kinds of light rays are incident on the same position on the surface of the object to be measured in both directions to generate two light spots having a large diameter and a small diameter , and the respective reflected lights are optical paths of other incident lights. The optical system is configured to travel in the direction. In this case, it is preferable to use two light beams separated from the same light source or two light beams mechanically coupled together.

Further , in the one using one optical system, the diameter of the light spot is varied, and in synchronization with this variation, an output signal corresponding to the small diameter light spot and an output signal corresponding to the large diameter light spot are generated. Separately taken out, the surface shape of the object to be measured is detected by using these two kinds of output signals.

[0009]

According to the present invention, one of the light spots has a small diameter and the other has a large diameter . Therefore , the output signal due to the reflected light from the light spot having a small diameter causes unevenness of the surface of the object to be measured, mechanical vibration, etc. It contains information about both the displacement of the surface of the object to be measured and the output signal due to the reflected light from the large-diameter spot averages the irregularities that are included in the output signal. It mainly consists of displacement information.
Therefore, by obtaining the difference between the two output signals, the common information corresponding to the displacement of the surface contained in both signals is canceled out, and the signal corresponding to only the unevenness of the surface is taken out and mechanically extracted. Disturbance due to vibration or the like is removed.

Moreover, for example, two types of light rays are displayed on the measured object surface.
Two light spots are incident on the same surface from both directions.
Occurs, and each reflected light is in the optical path direction of other incident light
If you choose to proceed to
If the light spot changes depending on whether it changes or the tilt changes,
The mode of change of each output signal due to the reflected light is different.
Change in the position of the DUT surface and tilt.
Allows accurate measurement by clearly distinguishing from changes in slope
It becomes Noh.

[0011]

First Embodiment First, the structure and principle of the present invention will be described with reference to a general light spot displacement method with reference to the embodiments shown in FIGS. It should be noted that this embodiment corresponds to claim 2 . 1 and 2 show the XY plane and Y of the device.
FIGS. 3A and 3B are a plan view and a side view showing a basic arrangement on the −Z plane, in which 1 is a first optical system, 2 is a second optical system, 3 is an object to be measured, and 4 is an arithmetic means. .

The optical system 1 is a parallel or nearly parallel light beam 1.
The light source 12 which emits 1 and enters the DUT 3, the condensing lens 14 which collects the light beam 11 and produces a small light spot 13 on the surface of the DUT 3, and the reflected light 15 from the DUT 3 are parallel. Alternatively, it is composed of an objective lens 16 for converting the light into substantially parallel rays, a semiconductor position detecting device 17 for receiving the reflected light 15 and outputting an electric signal according to the light receiving state. Further, the optical system 2 similarly includes a light source 22 which emits a parallel or nearly parallel light beam 21, a condenser lens 24 which condenses the light beam 21 to generate a relatively large light spot 23, and a reflected light 25 which is a parallel or substantially parallel light beam. Objective lens 26, reflected light 25
It is composed of a semiconductor position detecting device 27 and the like which outputs an electric signal according to the light receiving state of.

As shown in FIG. 2, the optical systems 1 and 2 are mounted on the lens mounts 18 and 28, and the lenses 14, 16 and 2 are mounted on the lens mounts 18 and 28.
4 and 26 are held, and the light rays 11 and 21 are obliquely measured.
The reflected light 15 and 25 reflected by the surface 30 is incident on the objective lenses 16 and 26.
The incident angle of the light rays 11 and 21 is generally selected to be about 30 to 50 °. Further, for example, a laser light source is used as the light sources 12 and 22, and a square-index refractive index cylindrical lens is used for each lens. The semiconductor position detecting devices 17 and 27 convert the center positions of the light spots of the incident reflected lights 15 and 25 into electric signals and output the electric signals. It is configured to output the effective central position of the light spot in response to the light intensity distribution and the change in spot diameter.

The structure of each of the optical systems 1 and 2 is basically the same as that of the conventionally known optical system based on the light spot displacement method. Therefore, further description of the structure will be omitted. To do. Further, in the following description, the description will be made mainly using the reference numerals of the first optical system 1 for convenience , but the operation of the second optical system 2 is similar.

In FIG. 2, the solid line indicates a position where the reflected light 15 is incident on the center of the objective lens 16, goes straight, and is incident on the center of the semiconductor position detecting device 17 as it is.
There is a state. Here, the surface 3 of the DUT 3
When 0 is displaced by the distance a or b to the position indicated by the two-dot chain line 30a or the one-dot chain line 30b, respectively, the objective lens 1
The incident position on 6 is shifted and the reflected light is bent like 15a or 15b, and the emission angle becomes θ1 or θ2, respectively. Therefore, if the distance from the emission end face of the objective lens 16 to the semiconductor position detecting device 17 is R, the incident position of the reflected light is approximately displaced from the center of the semiconductor position detecting device 17 by Rθ1 or Rθ2, respectively.

FIG. 6 is a diagram for explaining the operation of the semiconductor position detecting device 17. Now, when the center of the reflected light 15 enters at a position displaced from the center S0 of the effective length S by the distance A, the center terminal T
With 0 as a common terminal, the output current I1,
I2 flows, and the ratio of the difference and the sum becomes (I2-I1) / (I2 + I1) = 2A / S, which corresponds to the ratio of the distance A to the effective length S.
Therefore, the center position A of the reflected light 15 can be detected irrespective of the magnitude of the light energy incident on the semiconductor position detecting device 17 and the size of the light spot.
The displacement of the incident position of 5 by Rθ1 or Rθ2 is detected as an electric signal, and the arithmetic unit 4 performs a predetermined arithmetic processing to calculate the position of the surface 30 of the DUT 3 in the Z-axis direction. .

FIG. 3 is an explanatory diagram in the case where there is a step on the surface of the object to be measured and a light beam is incident on that part. That is,
As shown in the figure, when there is a step of height d on the surface 30 of the object to be measured and the light ray 11 is incident with a width W1, the reflected light at the center of the light ray 11 is 15'-1 or 15'-2 due to the effect of the step. And the reflected light of the light rays 11a and 11b at both ends is 15'a.
And 15'b, the light enters the objective lens 16 respectively, and the exit angle after passing through the lens 16 changes according to the incident position. Therefore, the width of the reflected light incident on the semiconductor position detecting device 17 becomes wider than that when there is no step, but as described above, the semiconductor position detecting device 17 has an effective center regardless of the size of the light spot of the incident light. Position 15 'is detected.

That is, when there is a step d at the center of the width W1 of the incident light, there is a virtual surface 30 'at the average position within the width W1' of the light spot, that is, at a height half the step d, and the center is 15 ', and both ends are 15 "a and 15" b, which are approximately the same as when the reflected light enters the objective lens 16. Further, if the position of the step d deviates to one side within the width W1 ', the position of the virtual surface 30' of the object to be detected detected corresponding to the deviation also deviates, and the average position within the width W1 'is detected. To be done.

Next, the case where the surface is triangular as shown in FIG. 4 will be described. In this case, geometrically, the reflected light at the center of the incident light ray 11 is as shown by 15 ', and the reflected light of the light rays 11c and 11d at both ends incident at the width W2 is 15'c,
Since the light rays 15'd enter the objective lens 16 respectively, the reflected light rays 15 ", 15" c, 1 from the virtual plane 30 'at the position of the width W2' corresponding to the light rays 11c, 11d.
The position and angle of incidence are quite different from those of 5 ″ d. However, the ray incident near the peak is re-emitted after slightly penetrating into the reflection surface, and its emission angle is the geometric reflection angle. Since it is known that the reflected light at the center is incident on the objective lens 16 like 15'-3, the reflected lights 15'c and 15'd are displaced in the opposite directions. As a result, the output current of the semiconductor position detecting device 17 is approximately outputted as a value corresponding to the reflected light 15 ″, and the position of the virtual plane 30 ′ is detected.

If the portion where the light spot by the light beam 11 is generated is an inclined plane, the incident position on the objective lens 16 is translated in one direction as a whole, and the surface is detected by this translation and processed. The average position of can be detected. Since the position of the surface of the DUT 3 is detected as described above, the unevenness of the DUT surface can be detected by moving the optical system 1 relative to the DUT 3. The smaller the diameter of the light spot generated on the object 3, the higher the resolution, and the finer the shape can be measured.

On the other hand, as shown in FIG. 5, the effective width W3 of the light beam 11
The width W3 'of the light spot corresponding to the
When the average pitch of the unevenness of the surface is much larger than the average pitch of the unevenness of the surface 30, diffuse reflection is generated from the surface 30, but the main part of the reflected light 15 is in the state of the reflected light from the virtual plane 30 ′ obtained by averaging the unevenness of the surface 30. The output current of the detection device 17 corresponds to this. That is, the unevenness of the plane 30 'is not detected, but the average position of the plane 30' is detected, and when the DUT 3 vibrates in the Z-axis direction or is displaced entirely, the vibration or displacement is detected. It will be.

Therefore, as shown in FIG. 1, when a small optical spot 13 is generated on the DUT 3 by the first optical system 1 and a large optical spot 23 is generated by the second optical system 2, the optical system is measured. In No. 1, irregularities with a fine pitch corresponding to the small light spot 13 are detected, and in the optical system 2, irregularities as detected by the optical system 1 are not detected. If the DUT 3 is vibrating, the displacement of the surface of the DUT 3 due to the vibration is also included in the detection results of the optical systems 1 and 2 and is simultaneously detected. Therefore, the semiconductor position detecting device 17 of both optical systems,
By obtaining the difference between the output signals of 27, the signal components corresponding to the displacement of the surface contained in both signals are canceled out, the influence of vibration is removed, and the measurement result corresponding to only the surface irregularities is obtained. It is possible to measure the surface shape at the same time as the processing by incorporating this device into a processing step involving mechanical vibration.

The small light spot 13 from the optical system 1 and the large light spot 23 from the optical system 2 are
It can be easily obtained by appropriately selecting the focal lengths of 4, 24 and the distance to the DUT 3. FIG. 7 illustrates this. FIG. 7A is a diagram showing an example of the intensity distribution of the light rays emitted from the condenser lenses 14 and 24 by a ray bundle, and FIG. 7B is a view at different positions on the optical axis. It is an intensity distribution map.

In the figure, 32 is the maximum resolution image plane where the light spot diameter is the smallest, 32 'is the intensity distribution obtained on that surface, 33 is the Gaussian image plane, 33' is the intensity distribution obtained on that surface, and 34 is Maximum contrast image plane, 34 '
Indicates the intensity distribution obtained on that surface, 35 indicates the large spot diameter plane where the light spot diameter increases, and 35 'indicates the intensity distribution obtained on that surface. Therefore, by configuring the optical systems 1 and 2 so that the surface of the object to be measured is located, for example, in the maximum resolution image plane 32 in the optical system 1 and in the large spot diameter plane 35 in the optical system 2, the focus of It is possible to generate a small light spot 13 that is narrowed and a large light spot 23 that is defocused and enlarged. In (a), the broken lines 32a and 35a respectively indicate the positions of the surface of the object to be measured which are arranged to be inclined with respect to the optical axis.

As shown in FIG. 1, the optical systems 1 and 2
When they are arranged apart from each other, for example, when the DUT 3 is held in a cantilever manner and vibrates, the amplitude varies depending on the position of the light spot, which causes a measurement error. This difference in amplitude can be corrected during the calculation processing by the calculation means 4 when the mode of vibration is known in advance, but if the distance between the light spots 13 and 23 is reduced, it is not necessary to correct it. Since the light spots 13 and 23 are lowered and the light spots 13 and 23 are formed at the same position, no correction is necessary. Producing a light spot at the same location in this way is effective for both optical systems 1 and 2.
Can be realized by arranging so that the optical axes cross each other instead of being arranged in parallel as shown in FIG.
The following optical system does not cause such a problem.

Further, the detection sensitivities of the optical systems 1 and 2 differ with respect to the displacement of the surface position depending on the surface condition of the object 3 to be measured, etc. This problem can be adjusted in advance by providing a calibration means. Alternatively, or by making it possible to correct the sensitivity difference between the two optical systems during the arithmetic processing, the problem can be easily solved.

[0027]

Second Embodiment Next, an embodiment corresponding to claim 4 will be described with reference to FIGS. FIG. 8 is a side view showing the basic arrangement of the device on the YZ plane, and FIG. 9 is an explanatory diagram of the operating principle.

In the figure, reference numeral 41 denotes one optical system, in which two light sources 42 and 52 are arranged at both ends to send out light rays 42-1 and 52-1 from both directions, and two light sources having different diameters are provided. The light spots 46 and 56 are formed at the same location on the surface 30 of the object to be measured, and the respective reflected lights are configured to travel in the optical path directions of the other incident lights. 53 reflected light 42-2, 52-
2 is bent so as to be incident on the semiconductor position detecting devices 44 and 54. Reference numerals 45 and 55 are lenses that serve both as a condenser and an objective, and other configurations are based on the above-mentioned optical systems 12 and 22. The calculation means is not shown.

In FIG. 9, when the surface 30 to be measured is inclined by an angle θ with respect to the reference surface 30 ", the surface 30
The upper normal line N is also inclined by an angle θ with respect to the normal line N ′ of the reference plane 30 ″, and the reflected light 42-2 of the light ray 42-1 from the right light source 42 is reflected from the reference plane 30 ″. Light 42'-2
Then, the light beam is deflected by 2θ and enters the detection device 54. In addition,
For convenience of explanation, the optical path in the figure is drawn without bending.

On the other hand, a ray 52-1 from the light source 52 on the left side
Reflected light 52-2 is reflected light 52'-from the reference surface 30 ".
It is deflected by 2θ from 2 and enters the detection device 44. The deflection directions at this time are both clockwise, and if the coordinates on the detection devices 44 and 54 are selected as shown in the figure, the reflected light 4
The incident position of 2-2 swings to the + B side, and the reflected light 52-2 swings to the -A side. On the other hand, the measured object surface 30
Is displaced by a distance d with respect to the reference plane 30 ″ as indicated by a chain line 30d, the reflected lights are 42-2d and 52-2, respectively.
As shown by -2d, both are displaced upward in the drawing, and the incident position of the reflected light 42-2d swings to the + B side and the incident position of the reflected light 52-2d swings to the + A side.

That is, when the surface 30 of the object to be measured is inclined, the sign of the incident position of the reflected light has the opposite sign, and when the position changes, the sign of the incident position has the same sign. It is possible to distinguish between the change in the position of the measured object surface 30 and the change in the inclination by detecting the coincidence / disagreement with each other. Further, the change amount itself of the incident position of each reflected light is the position of the measured object surface 30 or Since it corresponds to the inclination, the incident position can be detected by, for example, obtaining the average of the absolute values of the output signals of the detection devices 44 and 54.

Therefore, since the amount of information obtained by not only detecting the change in the position but also detecting the inclination is increased, it is possible to measure the surface shape with higher accuracy than in the case where only the position is detected. It will be.

[0033]

[Third Embodiment] FIG. 10 is an embodiment corresponding to claim 4 , in which a convex lens 57 is inserted in the optical path from the light source 52 on the left side in FIG. 8 and a light beam 52 emitted from the light source 52 as shown by a broken line. It is configured such that -1 is once condensed and intersects, and then enters the lens 55 while spreading slightly. Others are the same as those in FIG. 8 and are all denoted by the same reference numerals. Therefore, in this embodiment, the light spot 46 formed by the light ray 42-1 has a small diameter as in FIG.
The light ray 52-1 becomes a large-diameter light spot 56 'without being fully stopped by the lens 55, and a small-diameter and large-diameter light spot similar to that in the first embodiment can be generated by one optical system 41.

With this structure, according to this embodiment, the surface of the object to be measured 30 is measured according to the principle described with reference to FIG.
It is possible to detect the position change and the inclination change separately, and it is also possible to detect the displacement of the surface 30 due to the vibration of the object to be measured, as in the first embodiment. It is possible to measure with high accuracy.

[0035]

Fourth Embodiment As in the second and third embodiments, the optical system 41 is used.
When the two light sources 42 and 52 are provided at both ends of the light source, the independent light sources 42 and 52 are arranged at optimum positions to concentrate the two light spots 46 and 56 at the same position on the surface 30 of the object to be measured. It's surprisingly difficult. Embodiment 4 corresponding to claim 5 shown in FIGS. 11 to 14 is a solution to this problem.
Is.

In FIG. 11, reference numeral 61 is a light source device configured to send out two parallel light rays 42-1 and 52-1, 62 is a half mirror, and 63 is an objective lens.
Others are indicated by the same reference numerals as those in the second embodiment. In this embodiment, one objective lens 63 is used to measure the surface 30 of the object to be measured.
Although two light spots 46 and 56 are generated in the above, the principle is the same as that in the second embodiment. That is, when the position or inclination of the surface 30 of the object to be measured changes, the positions at which the reflected lights 42-2 and 52-2 of the light rays 42-1 and 52-1 are incident on the detection devices 54 and 44, respectively, It is possible to detect the position of the measurement object surface 30 and the change in the inclination separately.

The light source device 61 includes a light beam 42-from one light source.
1 and 52-1 may be separately transmitted,
Also, two light sources may be fixed to the same substrate so that they can be handled as one light source, but in any case, two light beams are not separately obtained from two independent light sources. It is easy to properly arrange the light source so as to generate the two light spots 46 and 56 at the same position on the surface 30 to be measured, and the practicality is improved as compared with the second embodiment.

By inserting the lens system 65 in one optical path, for example, the optical path of the light ray 52-1 as shown by the chain line in FIG. 11, the focal position of the light ray 52-1 is changed and the light spot 56 has a large diameter. Therefore, similarly to the third embodiment, it becomes possible to detect the displacement of the surface 30 due to the vibration of the object to be measured and the surface shape of the object to be measured can be measured with higher accuracy.

In the light source device 61, in order to separate one light beam into two parallel or nearly parallel light beams, a method using a beam splitter and a mirror as shown in FIG.
As shown in FIG. 13, there is a method of separating by a polarizing action using a polarizing prism or the like, and a method of periodically moving a lens or a mirror as shown in FIG.

In FIG. 12A, a light beam 70 is separated by a cube beam splitter 71, one of which is used as an outgoing light 70a and the other is reflected by a mirror 72 to be an outgoing light 70b. Further, in (b), the beams are separated by the plate beam splitter 73, one of which is used as the outgoing light 70a as it is, and the other of which is reflected by the mirror 74 to be the outgoing light 70b. In any case, the distance h between the emitted lights 70a and 70b can be adjusted by changing the position of the mirror 72 or 74 as shown by the broken line.

In FIG. 13A, the light beam 70 is separated by the polarization beam splitter 75 into a P-polarized outgoing light 70P and an S-polarized outgoing light 70S, and the outgoing light 70P remains unchanged and the outgoing light 70S is mirrored. This is a system in which the light is reflected and emitted. Also, (b) is a Wollaston polarization separator 7
The incident light 70 is separated into a P-polarized outgoing light 70P and an S-polarized outgoing light 70S by 7, and both outgoing lights 7 are separated by a lens 78.
In this method, 0P and 70S are emitted in parallel. (a)
In (b), the lens 78 is adjusted by adjusting the position of the mirror 76.
The distance between the outgoing lights 70P and 70S can be changed by adjusting the position of.

In FIG. 14 (a), the lenses 81 and 82 are arranged so that the parallel light ray 80 is emitted again as a parallel light ray 80 ', and the lens 82 is displaced in the direction perpendicular to the optical axis as shown by the arrow. 83 is provided. This actuator 83 is driven by the signal 85 of the signal generator 84 to periodically change the direction of the light beam emitted from the lens 82, and this is emitted by the lens 86 in parallel with the emitted light 80a, 8a.
It is set to 0b. That is, in a manner similar to the embodiment shown in FIG. 16 described later, in synchronization with the signal 85 of the signal generator 84, for example, the emitted light 80a is used at the H level, and the emitted light 80b is used at the L level. By performing the above, it is possible to handle as two light beams in a time division manner.

In FIG. 14B, lenses 81 and 82 are arranged so that the parallel rays 80 and the reflected light thereof pass through the center, a mirror 87 is provided between the lenses 81 and 82, and this is indicated by an actuator 83 by an arrow. The actuator 83 is driven by the signal 85 of the signal generator 84 to periodically change the position of the light beam incident on the lens 82, and the light beam is emitted from the lens 82 in a different direction. A light ray and a light ray passing through the center are made parallel to each other by a lens 86 to be emitted lights 80a and 80b. Therefore, the emitted light 80a and the emitted light 80b are synchronized with the signal 85 of the signal generator 84.
Can be treated as two rays by processing in a time division manner.

[0044]

[Embodiment 5] Next, FIG. 15 corresponding to claim 6 in which two light rays are time-divisionally divided on the same optical path.
An example will be described. In FIG. 15, lenses 91 and 92 are arranged so that two parallel light rays 90 are emitted again as parallel light rays 90 '.
The light ray 90 'passing through 3 is focused on the object surface 30 to be measured,
The reflected light 90 ″ passes through the objective lens 94 and the detection device 95.
It is configured to be incident on. Further, the lens 91 is provided with an actuator 96 for displacing the lens 91 in the optical axis direction as indicated by an arrow, and this is driven by a signal 98 of a signal generator 97.

With the above construction, when the lens 91 is moved to the position indicated by the broken line by driving the actuator 96, the emitted light 90 'from the lens 92 changes its diffraction angle and spreads like the broken line. The focus position moves to the objective lens 94 side, and the diameter of the light spot on the surface 30 of the object to be measured increases, and the spot diameter incident on the detection device 95 also increases. On the other hand, since the detection device 95 detects the center position of the spot regardless of the size of the light spot diameter, the gate 99 is operated in synchronization with the signal 98 of the signal generator 97, and, for example, at the H level, the reflection of the solid line is reflected. Light 9
By outputting the output signal corresponding to 0 ″ and outputting the reflected light 90 ″ of the broken line at the L level, it is possible to perform the measurement using the small-diameter light spot and the large-diameter light spot in a time division manner. Of.

[0046]

As is apparent from the above-described embodiments, the present invention provides a surface shape measuring apparatus using the light spot displacement method,
Two types of light spots, large and small , are generated on the surface of the object to be measured, and the surface shape of the object to be measured is detected using the output signals from the reflected light of the respective light rays .

Therefore, the reflected light from the small diameter light spot is
Output signal and output by the reflected light from the large diameter light spot.
By including the difference between the force signals, both signals are included
Information that corresponds to the displacement of the surface that is
Distortion due to mechanical vibration etc.
Can be removed, and the measured object seems to vibrate.
Even if only the output signal according to the surface roughness and shape is taken
Can be issued. Therefore, for example, cutting with a precision lathe
Surface of the work piece to be incorporated into the grinding process and mirror polishing process
It can be used for applications such as condition inspection.
It

[0048] Further, as the two types of light rays results in two optical spot incident from two-way to the same portion of the workpiece surface, each of the reflected light travels to each other in the optical path direction of the other incident light In this case, since the mode of change of each output signal due to the reflected light from each light spot is different when the position of the DUT surface changes and when the inclination changes, the DUT surface The change in position and the change in inclination can be clearly distinguished, and the measurement accuracy can be improved.

Further, in the case of using two light rays split from the same light source or light rays of two light sources mechanically integrated as the light rays to be bidirectionally incident on the surface of the object to be measured, It is easy to generate two light spots at the same location on the surface of the object to be measured . Also optical spot
The diameter of the lens is changed, and a small-diameter optical spot is synchronized with this change.
Output signal corresponding to the output and a large-diameter light spot
By extracting the output signal separately, it is possible to
Measurement using a large diameter light spot and a large diameter light spot
I can.

[Brief description of drawings]

FIG. 1 is a plan view showing a basic configuration of a device according to a first embodiment.

FIG. 2 is a side view showing the basic configuration of the embodiment.

FIG. 3 is an operation explanatory diagram of the embodiment.

FIG. 4 is an operation explanatory diagram of the embodiment.

FIG. 5 is an operation explanatory diagram of the embodiment.

FIG. 6 is an operation explanatory view of the semiconductor position detecting device of the embodiment.

FIG. 7 is an intensity distribution diagram of light rays emitted from the condenser lens of the same example.

FIG. 8 is a side view showing the basic configuration of the device of the second embodiment.

FIG. 9 is an operation explanatory diagram of the embodiment.

FIG. 10 is a side view showing the basic configuration of the third embodiment.

FIG. 11 is a side view showing the basic configuration of the fourth embodiment.

FIG. 12 is a diagram showing a configuration example of a light source device of the same embodiment.

FIG. 13 is a diagram showing another configuration example of the light source device of the embodiment.

FIG. 14 is a diagram showing still another configuration example of the light source device of the embodiment.

FIG. 15 is a side view showing the basic configuration of the fifth embodiment.

[Explanation of symbols]

 1,2,41 Optical system 3 Object to be measured 4 Computing means 11,21,42-1,52-1,90 Light beam 12,22,42,52,61 Light source 13,23,46,56,56 'Light spot 15, 25, 42-2, 52-2, 90 ″ Reflected light 17, 27, 44, 54, 95 Semiconductor position detection device 30 Surface of object to be measured

Claims (6)

[Claims] 1. An optical system for obliquely incident a light beam on a surface of an object to be measured and receiving a reflected light from the surface, wherein a center position of a light point of the reflected light which is displaced according to a shape or a position of the surface is set. In a surface profile measuring device configured to detect the surface profile of an object to be measured by converting into an electrical signal, a small-diameter light spot is formed on the surface of the object to be measured by two kinds of light rays.
A surface profile measuring apparatus, characterized in that a large-diameter light spot is generated, and the surface profile of an object to be measured is detected by using an output signal of reflected light of each light beam. 2. The surface profile measuring apparatus according to claim 1, wherein two light spots of two kinds of light rays are generated by two independent optical systems. 3. Two light spots by two kinds of light rays
Claims configured to be produced by a single optical system
1. The surface shape measuring device according to 1. 4. A light beam is bidirectional to the same position on the surface of the object to be measured.
Incident from two, two large and small light spots, and
The reflected light travels in the optical path direction of other incident light.
The surface profile measuring apparatus according to claim 3, wherein an optical system is formed . 5. Two rays separated from the same light source
Measures the rays of two light sources that are mechanically coupled together
It is configured so that it is incident on the same place on the surface of the object from both directions.
The surface profile measuring device according to claim 4 . 6. The diameter of the light spot is changed, and
Synchronous output signal corresponding to small diameter light spot and large diameter
Separate the output signal corresponding to the light spot and take it out.
The surface shape of the object to be measured is detected using the two types of output signals
The surface profile measuring apparatus according to claim 3, which is configured to