JPS6011106A - Shape detecting device - Google Patents

Abstract

PURPOSE:To detect the rugged shape of a sample by discriminating a variable density level value of interference fringes in plural positions on the surface of the sample and detecting the relative positions of the sample and a microscope in each position on a basis of the signal of a discriminating means. CONSTITUTION:When a maximum value of variable density level peak values of interference fringes is held in a holding circuit 36, a comparing circuit 37 outputs a sampling signal to a sampling circuit 41, and a galvanomirror driving signal from a galvanomirror driving circuit 40 is read to detect the position of a sample 21 in the X direction, and the position detection signal of a position detecting sensor 33 is read to detect the relative position of the surface of the sample 21 to a microscope 22 in the Y direction. The galvanomirror driving signal, namely, the galvanomirror driving voltage given to a galvanomirror 27 is changed to repeat this operation in plural positions of the sample 21 in the X direction, thus detecting the rugged shape of the surface of the sample 21.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for detecting the uneven shape of an object using interference fringes.

Conventional configuration and its problems The specific configuration of a conventional shape recognition device is shown in FIG.

1 is a sample whose surface has a cylindrical shape, 2 is a light source that illuminates the sample, 3 is a reference light mirror, and 4 is a beam splitter.
The light emitted from the light source 2 is split into two beams by the beam splitter 4, and the light reflected from the surface of the sample 1 and the light reflected from the reference beam mirror 3 interfere to generate interference fringes. 5 is an objective lens, and 6 is a galvanometer mirror 17 that scans the sample 1.
is the slit provided on the real image plane of test f41, and 8 is the slit provided on the real image plane of test f41.
, lso h7 is a photomultiplier tube that detects the light passing through it.

9 is a filter that passes only light of a specific frequency. When the sample 1 is scanned on the galvanometer mirror 6, the photomultiplier tube 8
The waveform of the interference fringes detected by this method is shown in FIG. The first-order wave, the second-order wave, and
If we recognize each of these, we can know the surface shape of the sample from the wavelength of the illumination, but the amount of data is enormous, the signal processing is complicated, and it is difficult to understand the surface irregularities of the sample with a complex surface shape. It is difficult to recognize.

OBJECTS OF THE INVENTION In view of the above drawbacks, an object of the present invention is to provide a shape detection device that detects the uneven shape of a sample by simple signal processing.

A microscope having an interference fringe generating means, an imaging device or a photoelectric conversion device provided in the vicinity of a real image plane of the microscope, and a determining device for determining the density level of interference fringes obtained from the imaging device or the photoelectric conversion device; It comprises a detection means for detecting the relative position of the sample and the microscope, and determines interference fringe density level values at a plurality of locations on the surface of the sample, and detects the relationship between the sample and the microscope at each location based on the signal from the determination means. By detecting the relative position of the sample, it is possible to detect the uneven shape of the sample through sophisticated signal processing.

DESCRIPTION OF EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is a front view showing the first embodiment of the present invention. In FIG. 3, 21 is a sample, 22 is a microscope, and the microscope 22 includes a light source 23 and a beam splitter 24.
, reference light mirror 25. Objective lens 26. Galvano mirror
27, a slit 28° and a photomultiplier tube 29. The beam splitter 22 splits the light emitted from the light source 23 into two
Divided into light beams, the light reflected by the sample 21 and the reference beam mirror 2
Interference fringes are generated by the light reflected by 5. slit 28
is provided on the real image plane of the sample 21, and a photomultiplier tube 29 is provided behind the slit 28 and converts the light passing through the slit 28 into an electrical signal.

The galvanometer mirror 27 comes to rest at a plurality of locations depending on the applied voltage value, and determines the interference fringe detection position in the sample 21X direction.

30 is a table on which the microscope 22 is placed and moves in the direction of the sample 21Y. Reference numeral 31 denotes a motor, an output shaft of which is connected to a feed screw 32, which moves the microscope 22 in the direction of the sample 21Y. The motor 31 is mounted on a slide table (not shown) and moves in the Y direction together with the feed screw 32. 3
Reference numeral 3 denotes a position detection sensor for detecting the position of the microscope, and by knowing the position detection signal 9 of the position detection sensor 33 and the change in relative position between the sample 21 and the microscope 22, it is possible to know the irregularities of the sample 21. 34 is a control device to which an interference fringe detection signal and a position detection signal are input, and a galvano drive signal and a motor drive signal are output.

An example of the configuration of the control device 34 will be explained with reference to FIG.

35 is the peak value P1.35 of the density level of one cycle of interference fringes shown in FIG. P2. This is a peak value detection circuit that detects P3. The peak value detection circuit 35 outputs the peak value of the gray level to the holding circuit 36 and the comparison circuit 37. The holding circuit 36 holds the peak value of the gray level inputted from the peak value detection circuit 36, and compares the peak value - period before with the comparison circuit 3.
Output to 7. The comparison circuit 37 compares the gray level peak value input from the peak value detection circuit 35 with the gray level peak value input from the holding circuit 36 one cycle before.

Reference numeral 38 indicates a direction in which the motor 3 moves in a direction such that the peak value of the gray level inputted from the peak value detection circuit 35 to the comparison circuit 37 becomes larger than the peak value of the gray level inputted from the holding circuit 36.
A motor control circuit 39 controls the rotation direction of the motor 31, and 39 is a motor and a drive circuit that drive the motor 31. 4o is a galvano drive circuit that makes the galvano mirror 27 stand still at a plurality of locations. Reference numeral 41 denotes a sampling circuit, which receives a sampling signal from the comparison circuit 37 when the peak value of the gray level before - period reaches the maximum, reads the galvano drive signal from the galvano drive circuit 40 at that time, and reads the galvano drive signal from the position detection sensor 33. The detection signal is read and the uneven shape of the sample 21 is detected from both values.

Next, in the uneven shape detection device configured as shown in FIGS. 3 and 4, the Y of the surface of the sample 21 is measured while referring to FIG.
The principle of directional position detection will be explained.

When the light source 23 shown in FIG. 3 is an incoherent light such as a halogen light bulb, the coherent range is narrower than that of a coherent light such as a laser beam, and the density level of the interference fringes varies depending on the distance from the light source 23 to the sample 21. , becomes maximum when the distances from the light source 23 to the reference beam mirror 25 are equal, that is, when the lights emitted from the light sources at the same time interfere with each other. Therefore, when the relative distance between the sample 21 and the microscope 22 is changed, the interference fringes become gradually clearer as shown in FIG. The interference fringes are the clearest at position B, where the distances are equal, and as they pass through position B, the interference fringes gradually become unclear.

When a change in the density level of this interference fringe is detected by a photomultiplier tube 29 based on a change in the amount of light passing through the slit 28, the detection signal has a waveform as shown in FIG. Therefore, by detecting the relative distance between the sample 21 and the microscope 22 at a plurality of locations in the X direction of the sample 21 when the density level of the interference fringes is maximum, the uneven shape of the sample 21 in the X direction can be known.

Next, the operation of this embodiment will be explained.

A galvanometer drive signal is given to the galvanomirror 27,
It swings by a predetermined angle and remains stationary, and the motor control circuit 3
8 drives the motor 31 in one direction via a motor drive circuit 39. At this time, the density level of the interference fringe caused by the light reflected from the sample 21 and the light reflected from the reference beam mirror 25 is photoelectrically converted by the photomultiplier tube 29, and the peak value of the density level of the interference fringe period is detected by the peak value detection circuit 36. Detect.

The peak value detection circuit 35 outputs the gray level peak value to the holding circuit 36 and the comparison circuit 37. The holding circuit 36 outputs the peak value of the gray level one cycle before to the comparing circuit 37, and the comparing circuit 37 compares both values. The gray level peak value of the holding circuit 36 is updated when the comparison circuit 37 completes the comparison. The gray level peak value input from the peak value detection circuit 35 to the comparison circuit 37 is stored in the holding circuit 36.
When the intensity level is greater than the peak value of the previous interference fringe period, the motor control circuit 38 continues to rotate the motor 31 in the same direction. Next, the peak value before the interference fringe period inputted from the holding circuit 36 is
6, when the maximum value of the interference fringe density level peak value is held in the holding circuit 36, the comparison circuit 36 outputs a sampling signal to the sampling circuit 41. . When the sampling signal is input to the sampling circuit 41, the galvano drive signal is read from the galvano drive circuit 4o to detect the position of the sample 21 in the X direction, and the position detection signal of the position detection sensor 33 is read, and the surface of the sample 2.1 is detected. The relative position of the microscope-2-2 in the Y direction is detected. Sample 21
The uneven shape of the surface of the sample 21 is detected repeatedly at a plurality of locations in the direction.

As described above, there is provided a microscope having an interference fringe generating means, a photoelectric converter, an interference fringe gray level peak value detection circuit, a holding circuit that holds the gray level peak value and outputs the peak value of one cycle before, and the peak value of the interference fringe. A comparison circuit that compares the output of the value detection circuit and the output of the holding circuit, and a position detection means that detects the relative position of the sample and the microscope are provided, and a comparison circuit that compares the output of the value detection circuit and the output of the holding circuit is provided. By detecting the relative position of the sample and the microscope at multiple locations on the sample surface, the uneven shape of the sample can be known with high accuracy through simple signal processing.

A second embodiment of the present invention will be described below.

FIG. 7 is a block diagram showing an example of a control device in the second embodiment. The configuration l'J other than the W71J control device is the same as that in FIG. 3 of the first embodiment. In FIG. 7, 42 is a detection circuit for detecting the interference fringe density level, and 43 is a comparison circuit that compares the output value of the detection circuit 42 with a predetermined predetermined value of the interference fringe density level. 44 is a motor control circuit, and 46 is a motor drive circuit.

47 is a sampling circuit, and when the output value of the detection circuit 42 exceeds a predetermined value of the interference fringe density level, a sampling signal is inputted from the comparison circuit 43, and the galvano drive signal is read from the galvano drive circuit 46. A position detection signal is read from the position detection sensor and a shape signal of the sample 21 is output.

The operation of the shape detection device configured as described above will be explained below.

A galvano drive signal is applied to the galvano mirror 27,
The motor control circuit 44 rotates the motor 31 in one direction after swinging by a predetermined angle and coming to rest. Move the microscope 22 in one direction. At this time, the interference fringe density level is determined by the photomultiplier tube 29.
photoelectrically converted and detected by the detection circuit 42. The comparison circuit 43 receives the value of the interference fringe density level from the detection circuit 42, and if it exceeds a predetermined value, the comparison circuit 43 outputs the sampling signal to the sampling circuit 4.
7 is output. When a sampling signal is input to the sampling circuit 47, the galvano drive signal is read from the galvano drive circuit 46 and the position of the sample 21 in the X direction is detected.The position detection signal is read from the position detection sensor 33 and the microscope moves the sample 21 in the Y direction. Detects the relative position with.

Ten or more operations are repeated at a plurality of locations in the X direction of the sample 21 by changing the galvano drive signal applied to the galvanometer mirror 27 to detect the uneven shape of the surface of the sample 21.

As described above, a detection circuit that detects the density level of interference fringes and a comparison circuit that compares the density level of interference fringes detected by the detection circuit with a predetermined value are provided, and when the density level of interference fringes exceeds a predetermined value, the sample By detecting the relative position of the sample and the microscope at multiple locations on the sample surface, the uneven shape of the sample can be determined quickly with simple signal processing.

Note that in the first and second embodiments, a photomultiplier tube is used as a means for detecting interference fringes, but it is also possible to use an ITV camera or a diode array photoelectric conversion element. This is not included in the present invention.

Ox 1 is the first. In the second embodiment, the sample is scanned by a carbanomirror, but the effect is the same even if the sample is moved or the sample is moved.

Effects of the Invention The present invention includes a microscope having an interference fringe generating means, an imaging device or a photoelectric conversion device provided near the real image plane of the microscope, and a determination device for determining an interference fringe density level value obtained from the imaging device or the photoelectric conversion device. , comprising a position detection means for detecting the relative position between the sample 21 and the microscope, determines interference fringe density level values at a plurality of locations on the sample surface, and detects the surface of the sample 21 based on the signal from the determination means. By detecting the relative position with respect to the microscope and detecting the uneven shape of the sample, it is possible to determine the accuracy and the uneven shape of the sample through simple signal processing.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of a conventional example, FIG. 2 is an explanatory diagram showing waveforms of interference fringes, FIG. 3 is an explanatory diagram showing an embodiment of the shape detection device of the present invention, and FIG. A block diagram showing the control device in the first embodiment of the present invention, FIG. 5 is an explanatory diagram showing the shading level of interference fringes, and FIGS. 6 a and b are explanatory diagrams showing changes in the shading level of interference fringes. FIG. 7 is a dimensional block diagram of a control device according to a second embodiment of the present invention. 21... Trial, 22... Microscope, 23-...
5'el, 24...-beam splitter, 25...
・Reference light mirror, 26... Objective lens, 27.
... Galvano mirror 128 ... Slit, 2
9...Photomultiplier tube. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure 2 Figure 4 Figure 5 Figure 6

Claims (5)

[Claims] (1) a microscope having an interference fringe generating means; a naked image device or a photoelectric conversion device provided near the real image plane of the microscope;
It consists of a determining means for determining the interference fringe density level value obtained from the imaging device or the photoelectric conversion device, and a position detecting means for detecting the relative position of the sample and the microscope, and the interference fringe a is detected at a plurality of locations on the sample surface. A shape detection device that determines a lightening value and detects a relative position between the sample and the microscope based on a signal from the determination means. (2) The determination means detects the peak value of the interference fringe density level value for each cycle, and the relative relationship between the sample and the microscope in the vicinity of the cycle in which the peak value of the density level value for each cycle becomes the maximum value. A shape detection device according to claim 1, which detects a position. (3) The determination means holds a peak value detection circuit that detects the peak value of the interference fringe density level value for each cycle and the peak value detected by the peak value detection circuit, and stores the peak value detected by the peak value detection circuit -cycle before. The peak value outputted from the peak value detection circuit includes a holding circuit that outputs the output, and a comparison circuit that compares the gray level peak value outputted from the peak value detection circuit with the peak value outputted from the holding circuit one cycle before. 2. A shape detecting device according to claim 1, which detects the relative position of said sample and said microscope when a peak value of said sample becomes smaller than a peak value of one cycle before outputted from said holding circuit. (4) Shape detection according to claim 1, wherein the determining means detects a relative position between the sample and the microscope when the interference fringe density level value becomes equal to or higher than a D-test level value. Device. (5) The determination means comprises a detection circuit that detects the interference fringe density level value, and a comparison circuit that compares the output value of the detection circuit with a predetermined value, and the interference fringe density level value is equal to or greater than a predetermined value. 2. The shape detection device according to claim 1, wherein the relative position between the sample and the microscope is detected by a signal from the comparison circuit indicating that the shape has become .