JPH0225710A - Measuring method for misalignment quantity and automatic focusing mechanism, surface roughness measuring instrument and pattern inspecting device using said method - Google Patents

Abstract

PURPOSE:To execute the measurement without being influenced by a member whose reflection factor is different by attenuating a regularly reflected light from the member and a background part, in a reflected light from a light spot image, detecting a scattered reflected light and measuring the misalignment quantity in the vertical direction. CONSTITUTION:A light spot 122 which is formed on a sample 126 constituted of a pattern 124 and its background part 125 by a light source 90 is converted to a photoelectric converting signal 97 by a detecting means 123. The photoelectric converting signal 97 has a waveform as shown on a code 102, and inputted to a position measuring means 98. In the position measuring means 98, a variation DELTAZ in the vertical direction (Z direction) of the sample 126 is calculated. In this case, since a reflected light from the pattern 124 is mainly a regularly reflected light, this regularly reflected light is attenuated by an optical means 121. On the other hand, a reflected light beam from the light spot 122 contains both components of a regularly reflected light beam and a scattered light beam, therefore, only a detecting signal corresponding to the light spot 122 is mainly detected on the code 102. In such a way, a peak position of the detecting signal 104 can be detected exactly.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method and device for measuring the amount of positional deviation,
In particular, in a microscope or the like, a positional deviation amount measuring method and apparatus suitable for measuring and correcting vertical positional deviation of a sample surface from a focused position, and an automatic focusing mechanism using the method and apparatus, The present invention relates to a surface roughness measuring device and a pattern inspection device.

[Prior Art] A conventional positional deviation pointer measuring device is described in, for example, Monthly Semiconductor World (Semiconductor World).
rld) 1984/5, "Microscope automatic focusing mechanism", a light spot is imaged on the surface of the sample, and the formed light spot image is detected by a differential diode. Things are being introduced. More specifically, as shown in FIG. 11, when a laser diode 70 is used to form a light spot on a sample 77 and this light spot is detected by a differential diode 73, the differential diode 73 outputs a The calculation is performed by a dynamic amplifier 84.

That is, as shown in FIG. 12(a), when the sample 77 is at position F, the output 81 is
When the sample 77 is at the position F-Δ, output 83 is output.
When it is at F, outputs 82 are obtained, and the position of the sample 77 can be detected by detecting the peak value of the output 81 among them with a position detection circuit.

Furthermore, as disclosed in the prior art, for example, in Japanese Patent Application Laid-Open No. 55-96406, the schematic structure of which is shown in FIG.
1, a grating image 63 is captured by the detector 56 via the lens 55. As shown in FIG. 13(b), this grating image 63 is an image of the portion of the grating 52 through which light passes, and the portion of the grating 52 through which light does not pass is the upper surface of the object 62.

Next, when the grating image 63 from the detector 56 is input to the position detecting means 57, the position detecting means 57 detects the level of the grating image 63 in the scanning line direction shown in FIG. 13(b) (FIG. 13(C)). The contrast, that is, the height difference in the signal level obtained corresponding to the brightness and darkness of the grating 52 is detected using , a method for determining the amount of vertical displacement of an object 62 on a stage 60 has been introduced.

[Problems to be Solved by the Invention] In the prior art, no consideration is given to the case where a sample as an object has patterns with different reflectances, and in the former prior art, as shown in FIG. ), the output of the differential amplifier 84 is affected by the pattern 79 and generates a peak 80, so the output 81 when the original sample 77 is at position [F] cannot be distinguished. However, there was a problem in that errors occurred when measuring the amount of positional deviation.

Furthermore, even with the latter conventional technique, there is a problem in that an error occurs in calculating the amount of positional deviation, making it difficult to accurately measure the amount of positional deviation.

In addition, as mentioned above, since the sample has members such as patterns with different reflectances, errors occur in calculating the amount of positional deviation of the sample, making it difficult to accurately calculate the amount of positional deviation.
For example, this problem also occurs in automatic focusing mechanisms, surface roughness measuring devices, pattern inspection devices for printed circuit boards, and the like.

An object of the present invention is to provide a method and apparatus for measuring positional deviation, which enables accurate measurement of positional deviation without being affected by the members, even in samples having members having different reflectances, and a method and apparatus for the same. The present invention provides an automatic focusing mechanism, a surface roughness measuring device, and a pattern inspection device for printed circuit boards.

[Means for Solving the Problems] In order to achieve the above object, in the positional deviation measurement method of the present invention, illumination is A light spot position detection means comprising a light spot position detecting means, an optical means, and a detection means forms a light spot image, and among the light reflected from the light spot image, specularly reflected light from the member and background portion is attenuated, and scattered reflected light is attenuated. This is detected and photoelectrically converted, and from the photoelectrically converted signal, a position measuring means calculates and measures the amount of vertical positional deviation of the sample.

Further, since the illumination means uses normal illumination light, it has an optical means.

Further, the optical means is constructed of a polarizing plate in order to simplify the construction.

Further, the illumination means uses a light source having polarized light in order to simplify adjustment.

In addition, in order to reduce the influence of reflected light from the member, the one-position measuring means calculates the sum of the photoelectric conversion signals from the detection means in an arbitrary range, and calculates the amount of positional deviation of the sample from the peak value of the calculated sum signal. It is calculated and measured.

In addition, the position measuring means determines the center of gravity of the photoelectric conversion signal from the detection means in order to accurately measure the amount of positional deviation of the sample even if there is a peak generated in the member, and the position of the sample is determined from the obtained center of gravity position. The amount of deviation is calculated and measured.

In addition, since the detection means has an optical axis at a position that does not coincide with the reflected optical axis of the light spot image on the sample surface, which corresponds to the illumination optical axis of the illumination means, the detection means detects specularly reflected light from the light spot image on the sample surface. can be attenuated.

In addition, in order to achieve the above object, the positional deviation position measuring means of the present invention includes a slit illumination means, an optical means, and a slit detection means on the surface of the sample consisting of members having mutually different reflectances and the background part of the members. A slit image is formed by a slit detection means consisting of an optical means, and among the reflected light from the slit image, regular reflected light from the member and the background is attenuated, scattered reflected light is detected and photoelectrically converted, and the reflected light is photoelectrically converted. The amount of vertical positional deviation of the sample is calculated and measured using a position measuring means from the photoelectric conversion signal.

Further, the slit detection means is configured to allow only scattered polarized light to pass through, in order to omit optical means and simplify adjustment.

In addition, in order to attenuate the specularly reflected light from the slit image on the sample surface, the slit detection means places the optical axis at a position that does not coincide with the reflected optical axis of the slit image on the sample surface, which corresponds to the illumination optical axis from the illumination means. It has the following.

Further, the position measuring means calculates and measures the amount of positional deviation of the sample from the contrast of the slit image in the photoelectric conversion signal from the slit detecting means.

Further, in order to achieve the above object, an automatic focusing mechanism of the present invention uses the above positional deviation measurement method.

Further, in order to achieve the above object, a surface roughness measuring device of the present invention uses the above positional deviation amount measuring method.

Moreover, in order to achieve the above-mentioned object, a pattern inspection device of the present invention uses the above-mentioned positional deviation amount measuring method.

[Function] In the method for measuring the amount of positional deviation of the present invention as described above, the following actions are performed.

As shown in FIG. 13(a), when the grating 52 is projected by the light source 51 onto the object 62 using the lens 53, the object 62 is a base formed of a material with low reflectance that forms the background of the pattern section 61. It is composed of a material part 62 and a pattern part 61 formed of a material with a high reflectance, and an image 63a of a part of the grating 52 that transmits light and an image 63b of a part that does not transmit light are shown on the base material part 62. are projected and the reflectances from these images 63a and 63b are significantly different, the image captured by the detection means 56 will be the 13th image.
As shown in FIG. 13(d), the level in any scanning line direction is greatly influenced by the pattern portion 61 as shown in FIG. 13(e). That is, the bright level of the pattern part 61 is X, the bright level of the base material part 62 is y, and there is also a possibility that a peak W is generated due to the influence of reflection at the edge of the pattern part 61. Such an exceptional level of variation greatly affects the absolute value of the contrast calculation result and causes an error in calculating the amount of 1 position deviation, making it difficult to accurately measure the amount of position deviation. .

Therefore, in one method of measuring the amount of positional deviation according to the present invention, an image is formed using polarized light on the base member 62 by illumination means.

In this case, the difference in reflectance between the pattern portion 61 and the base material portion 62 in the base material portion 62 having a pattern is mainly due to the following.
Since the ratio of specularly reflected light of each material is different, by removing the specularly reflected light from the polarized light of the image by the detection means, the reflected light intensity of the light spot in each of the pattern portion 61 and the base material portion 62 can be roughly determined. This makes it possible to prevent misjudgment of the amount of positional deviation.

Furthermore, since the optical means is constituted by a polarizing plate, the structure can be made simple.

Furthermore, since the illumination means includes an optical means, normal illumination light can be used.

Furthermore, since a light source having polarized light is used as the illumination means, adjustment can be simplified.

In addition, the one-position measuring means calculates the sum of the photoelectric conversion signals from the detection means in an arbitrary range, and calculates and measures the amount of positional deviation of the sample from the peak value of the calculated sum signal. Stable measurements can be performed without being affected by conditions.

In addition, the position measuring means determines the center of gravity of the photoelectric conversion signal from the detection means, and calculates and measures the amount of positional deviation of the sample from the determined center of gravity position. The amount of positional deviation of the sample can be accurately measured without being affected.

That is, as shown in Figure 9, the photoelectric conversion is calculated,
Since the position is measured based on this point G, even if the peak of the photoelectric conversion signal is gentle and does not have a clear single peak characteristic, as shown in FIG.
Even if whisker-like peaks 41 occurring at the edge portions 7 are present, the amount of positional deviation can be accurately measured without being affected by these peaks.

In addition, since the optical axis is located at a position that does not coincide with the reflected optical axis of the light spot image on the sample surface, which corresponds to the illumination optical axis of the illumination means of the detection means, the specularly reflected light from the light spot image on the sample surface is attenuated. can do.

Furthermore, in the method for measuring the amount of positional deviation of the present invention as described above, members having different reflectances from each other and the members are detected by a slit detection means including a slit illumination means, an optical means, and a slit detection optical means. This method calculates and measures the amount of positional deviation of the sample from the brightness and darkness of the contrast of the wrist image based on the conversion signal, thereby making it possible to accurately measure the amount of positional deviation.

[Embodiment] Hereinafter, a description will be given of FIG. 1 showing a positional deviation pointer measuring device which is an embodiment of the present invention.

The embodiment shown in FIG. 1(a) includes a device 120 consisting of a light source 90 and a detection means 123, and a detection means 1 of the light spot position detection means 120.
23 is equipped with an optical means 121, and when the light source 90 forms a light spot 122 on a sample 126 composed of a pattern 124 and a background part 125 of the pattern 124,
This light spot 122 is converted into a photoelectric conversion signal 97 by the detection means 123. This photoelectric conversion signal 97 is input into the position measuring means 98 as a detection signal having a waveform as shown on the reference numeral 102 corresponding to the coordinates on the detecting means 123.

This position measuring means 98 calculates the amount of change ΔZ of the sample 126 in the vertical direction (Z direction), that is, the amount of change ΔZ of the sample 126 from the solid line position to the chain line position.

In this case, as shown in FIG. 1(b), the optical means 121
is not provided, pattern 1 of sample 126
24, the detection means 123 detects the detection signal 104 of the light spot 122 and the pattern 12 as shown on the reference numeral 102.
Furthermore, since the detection signal 105 generally has a higher reflectance than the detection signal 104, accurate measurement becomes a detour.

On the other hand, as shown in FIG. 1(c), the optical means 12
1, the optical means 121 illuminates the light spot 12.
The specularly reflected light component of the reflected light from 2 is attenuated. That is, in FIG. 1C, since the reflected light from the pattern 124 is mainly specularly reflected light, this specularly reflected light is significantly attenuated by the optical means 121.

On the other hand, since the reflected light from the light spot 122 includes both specularly reflected light and scattered light components, only the detection signal 104 corresponding to the light spot 122 is mainly detected on the reference numeral 102, and this causes the peak position of the detection signal 104 to be detected. can be detected accurately. Note that the configuration of the position measuring means 98 will be described later.

Next, a description will be given of FIG. 2 showing a positional deviation position and needle measuring device which is another embodiment of the present invention.

In the embodiment shown in FIG. 2(a), a light spot 122 is illuminated on a sample 126 by an illumination means 93 composed of a light source 90, an illumination optical system 92, and a polarizing plate 99 disposed between them.
When a light spot 122 is formed, a light spot position detection optical system 94, a photoelectric conversion element 95 formed by a CCD, etc.
The signal is converted into a photoelectric conversion signal 97 by a device detection means 96 comprising a polarizing plate 100.

This photoelectric conversion signal 97 is input into the position measuring means 98 as a detection signal having a waveform as shown on the reference numeral 102 corresponding to the coordinates on the photoelectric conversion element 95. The position measuring means 98 calculates the amount of change ΔΩ in the light spot position from the change in the peak value of the detection signal on the reference numeral 102, and calculates the amount of displacement of the light spot position on the surface of the sample 126 from this amount of change ΔΩ in the light spot position. ΔX is determined, and the displacement amount of the sample 105 in two directions from the solid line position to the chain line position is calculated from the displacement amount ΔX of the light spot position.

In this case, the sample 126 may be, for example, a printed circuit board such as an ordinary printed wiring board or a green sheet.

As shown in FIGS. 2(b) and 2(c), this printed circuit board lot is composed of a base material part 105 and a pattern part 103, and the base material part 105 is made of a polymeric material and has a rough surface. There is. Further, the pattern section 103 is made of copper,
Has luster.

Therefore, in FIG. 2(b) showing a case where the polarizing plate 100 is not provided as in the conventional case, the illumination means 93
has a finite spot diameter, and the detection signal indicated by reference numeral 102 on the photoelectric conversion element 95 includes a detection signal 104 caused by the light reflected from the original light spot 122 as well as a detection signal 104 from the pattern 103 with high reflectance. Useless signal 1 due to reflected light of
05 is detected, this useless signal 105 becomes a pseudo signal, and the detection signal 104 is generated by the reflected light from the light spot 122.
There were cases where the peak position could not be detected.

In contrast, in this embodiment, the polarizing plate 99 and the polarizing plate 100
Furthermore, the relationship between the polarizing plates 99 and 100 is such that the polarizing plate 100 is arranged to remove the specularly reflected light component of the light reflected from the light spot 122, and the polarizing plate 99 is arranged to remove the specularly reflected light component from the light reflected from the light spot 122. It is arranged to extract the reflected light of scattered light from the reflected light. Therefore, in FIG. 2(c), the detection signal 105 mainly due to the specularly reflected light component reflected by the pattern 103 is significantly attenuated. On the other hand, since the reflected light from the light spot 122 includes specular reflected light and scattered light components, the detection signal 104 indicated by reference numeral 102 mainly detects only the reflected light image corresponding to the light spot 122. can accurately detect the position of

Note that in this embodiment, the illumination means 93 is replaced by the light source 90.

Although it is composed of a polarizing plate 99 and an illumination optical system 92, the light source 9
It is also possible to use a light source with polarized light such as a zero-polarized laser. In this case, the polarizing plate 99 becomes unnecessary, and the device can be made smaller and the adjustment can be simplified.

Next, a description will be given of FIG. 3 showing a positional deviation position and needle measuring device which is still another embodiment of the present invention.

The difference between the embodiment shown in FIG. 3 and the embodiment shown in FIG. The two points are that a slit position detection optical system 111 is provided in place of the detection optical system 94, and the other parts are indicated by the same reference numerals as in FIG.

In this embodiment, the autofocus pattern 107 is imaged onto the printed circuit board 101 by the light source 90. The pattern imaged on the printed circuit board 101 is detected by a slit position detection optical system 111. It is converted into a photoelectric conversion signal 97 by a photoelectric conversion element 95 and a polarizing plate 100.

At this time, when the printed circuit board 101 is in the predetermined position shown by the solid line, the photoelectric conversion signal 97 is transmitted to the photoelectric conversion element 95.
The grating 99 is imaged as shown by the waveform 108 corresponding to each point above, but when the printed circuit board 101 is displaced by the displacement amount ΔZ as shown by the chain line, the grating image on the photoelectric conversion element 95 is waveform 1 is out of focus
The waveform becomes distorted like 09.

Position measuring means 106 into which the above photoelectric conversion signal 97 is input
are bright level A and dark level B of the photoelectric conversion signal 97
The displacement amount ΔZ is estimated from the contrast.

In this case, when the surface of the printed circuit board 101 is formed flat, there is a correlation between the contrast and the displacement amount ΔZ, so the displacement amount ΔZ can be accurately estimated by the method described above. However, the printed circuit board 101 is as shown in FIG. 3(b).
As shown in FIG. 3(c), when the patterns 103 have different reflectances, if there is no polarizing plate 100, there is a risk that an unnecessary signal 112 will be detected due to the influence of the pattern 103, as shown in FIG. 3(b). was there.

On the other hand, in this embodiment, a polarizing plate 100 is added as shown in FIG.

By arranging the components so as to attenuate the specularly reflected light component, the waveform 113 is not affected by the pattern 103.The reason for this is that, as described in the example shown in FIG. 112 is specularly reflected light from the pattern 103, which can be attenuated by the polarizing plate 100.

In this embodiment, the illumination means 114 includes a light source 90 and a polarizing plate 107, but it is also possible to use a light source with polarized light such as a polarized laser as shown in FIG. The configuration can be simplified and downsized.

It is also possible to integrate the autofocus pattern 107 by, for example, depositing a grating on a polarizing plate.
This simplifies the configuration of the device and allows it to be made smaller.

Furthermore, if the photoelectric conversion element 95 is an element that is sensitive only to a specific (scattered light) polarized light component, the polarizing plate 100 can be omitted. This can also be applied to the embodiment shown in FIG.

Next, a description will be given of FIG. 4, which shows an example of the case where the positional deviation position measuring device according to the present invention is applied to an automatic focusing mechanism and a surface roughness measuring mechanism.

The embodiment shown in FIG. 4 differs from the embodiment shown in FIG.
The difference is that the stage 20 on which the device 6 is mounted is moved in the vertical direction, and the other parts are indicated by the same reference numerals as in FIG. 2.

In this embodiment, the 1-position measuring means 98 calculates the displacement ΔZ from the variation ΔΩ of the light spot position, as in the embodiment shown in FIG. If the angle between the optical axis of the light spot position detection means 96 and the top surface of the sample 126 at this time is θ, then the relationship is as follows. Therefore, after measuring the amount of change Δ0 in the light spot position, the light spot position can be detected using the above equation. The motor 19 is driven by the command from the control circuit 18 to move the stage 20 in the vertical direction (Z
direction), the displacement amount Δ2 of the upper surface of the sample 126 can always be maintained at zero, thereby making it possible to configure an automatic focusing mechanism.

Further, if the control circuit 18 drives the motor 19 by an amount corresponding to the amount of change ΔΩ in the light spot position, then stops driving the motor 19 and measures the amount of movement ΔZ of the stage 20, the sample 1
Since it is possible to know the displacement of the top surface of the sample 126 with respect to the position of the stage 20 when the amount of change Δ2 in the position of the light spot on the top surface of the sample 126 is zero, this operation can be performed at multiple points on the top surface of the sample 126. The surface roughness of the sample 126 can be measured from the plurality of displacement amounts determined in .

Note that even if the illumination means 93 and light spot detection means 96 in this embodiment are replaced with the illumination means 114 and slit position detection means 110 in the embodiment shown in FIG. 3, the same functions as in this embodiment are obtained. Of course.

Next, FIG. 5, which shows a printed circuit board pattern inspection apparatus according to an embodiment of the present invention, will be described.

In conventional pattern inspection apparatuses for printed circuit boards, there has been a problem in that the inspection means is affected by defocusing due to warpage, waviness, etc. of the printed circuit board.

In other words, when it is necessary to increase the magnification for inspection as printed circuit board patterns become finer, the depth of focus of the detection optical system generally becomes shallower as the magnification increases. There was a risk that misalignment would occur.

In addition, when detecting the pattern on the surface of the printed circuit board after lamination in a multilayer printed circuit board, the variation in the thickness of the printed circuit board of each layer is added, so for example, if the thickness of each layer is 0.1 oa, the variation is ±5%. Then, 30
After laminating the printed circuit board in layers, 0. IXQ, 05X30
= 0.15 layer m, resulting in a maximum undulation of ±0.15 pus.

Therefore, in the conventional apparatus, there is a possibility that an erroneous determination may occur due to a focus shift, and it is necessary to add an automatic focusing mechanism.

Therefore, in the present invention, as an example of its implementation is shown in FIG.
to illuminate.

Next, the reflected light from the printed circuit board 23 is passed through a half mirror.
22 and magnified by the lens 24, the photoelectric conversion signal is detected by the detection means 25 and subjected to photoelectric conversion, and is input to the defect determination means 26. The photoelectric conversion signal input to the defect determination means 26 is Processed printed circuit board 23
Inspect the top for defects.

At this time, in this embodiment, the printed circuit board 23 is illuminated in a dot or a line by the illumination light source 27 for focal position detection, the lens 15 and the polarizing plate 43, and the dot or line image 16 is illuminated by the lens 28. The light is transmitted through the polarizing plate 44 and detected by the focal position detection means 29. Note that the polarizing plate 44 is arranged so as not to pass specularly reflected light among the reflected light from the image 16.

Therefore, in this embodiment, as already explained in other embodiments, when there is, for example, a focus position deviation amount ΔX on the printed circuit board 23, the detected light point on the focus position inspection means 29 is Since the amount of change ΔQ in the position is detected, the control means 30 is used to drive the motor 31 so that the amount of change ΔQ in the position of the light spot becomes zero, and the stage 32 is moved by 1 ΔX to move the position on the printed circuit board 23. Correct the amount of focal position shift.

Therefore, in this embodiment, even if a focal position shift occurs due to irregularities on the surface of the printed circuit board 23 to be inspected or a decrease in precision of the stage, this can be corrected and the focal position inspection can be performed without misjudgment. It can be carried out.

In addition, if the illumination light for focal position detection and the illumination light for inspection interfere with each other and cause an adverse effect, these side illumination lights should be separated so that they do not interfere with each other and placed so as to illuminate the printed circuit board. Or, the wavelength bands of both illumination lights are made to differ from each other.

Each optical system may be made independent by providing an optical filter that allows only light in the respective wavelength band to pass through.

Next, FIG. 6, which shows a printed circuit board pattern inspection apparatus according to another embodiment of the present invention, will be described.

In the embodiment shown in FIG. 6, a line sensor 33 is provided between the lens 24 and the defect determination means 26, and for illumination, the light source 21 is guided through an optical fiber 35 and emitted in a linear manner, and printed using a cylindrical lens 34. It is configured to illuminate the substrate 23 in a linear manner.

Therefore, in this embodiment, the linear illumination 36 on the printed circuit board 23 is detected by the lens 28 and the focal position detection means 29.

In this case, as already explained in the embodiment shown in FIG.
Unnecessary detection signal 1 due to pattern on printed circuit board 23
05 has a large effect when it coincides with the optical axis of the reflected light from the sample surface, which corresponds to the optical axis of the illumination means 93 shown in FIG. Therefore, in this embodiment, as shown in FIG. 1, accurate automatic focusing can be performed without detecting an unnecessary detection signal 105.

Furthermore, there is no need for a light for detecting the focal position, allowing the device to be made smaller and cheaper, and there is no need to take measures to prevent the detection light and the focal position detecting light from interfering with each other.

In this example, the case where the application is applied to a printed circuit board pattern inspection device has been described, but the invention is not limited to this. By offsetting the optical axis of the detection means, that is, the optical axis of the light spot detection means 96 with respect to the illumination means 93 shown in FIG. 2, or the optical axis of the slit position optical system 110 with respect to the illumination means 114 of FIG. Similar to the embodiment shown in Figure 6, the polarizing plate 99.100
Even without adding , the unnecessary reflected light image 1 shown in Fig. 2(b)
05 and the unnecessary detection signal 112 shown in FIG. 3(b), an accurate positional deviation and pointer measuring device can be obtained.

Next, the configuration of the position measuring means 98 shown in FIG. 2 will be explained in more detail.

In principle, the waveform of the detection signal obtained on the detection means 95 has the shape shown by the solid line in FIG.

On the other hand, when a printed circuit board is used as the sample 101, in reality, it is affected by the different reflectance between the base material and the copper pattern on the printed circuit board, or by the copper pattern edge, as shown in FIG. The waveforms shown in (a) and (b) are disturbed. That is, the focus detection light spot 39 is influenced by the steel pattern 37 and generates a peak as shown in a waveform 41 with respect to an ideal waveform 40.

And the peak position is an error δ with respect to the peak of waveform 40.
occurs.

To solve this problem, perform the following processing.

That is, as shown in FIG. 9, the intensity at point Qn on the detection means is calculated. , the position G of the focus detection light spot 39 is calculated using the following equation, assuming that the dark level of the detection means is IB.

y', = I. -IB In this case, as shown in FIG. 8, the detection waveform of the focus detection light spot 39 has a single-peak characteristic, so according to this method, the edge of the copper pattern 37 on the base member 38 of the printed circuit board It is possible to reduce the influence of whisker-like peaks that occur in the
This makes it possible to detect a stable focal position that is not affected by the surface condition of the object to be inspected.

Further, FIG. 10 showing another embodiment of the position measuring means 98 will be explained.

For the detection waveform shown in FIG. 10(a), the digit 1G of the focus detection light spot 39 in the area k on the arbitrary coordinate Q is set to G==max(N+) N+=, Σ x, +j j- Obtained by the calculation. Here, the value of k is the focus detection light point 39
It is best to set +1 to the value 2 corresponding to the size 42 of k.Thus, the sum of the light amounts in a certain area set by the value of k is when +1 in that area 2 includes all the focus detection light points 39. Maximum.

Therefore, according to this embodiment, it is possible to detect a stable focus detection light spot 39 that is not affected by the state of the printed circuit board.

[Effects of the Invention] Since the present invention has the method and structure described above, it produces the following effects.

In the positional deviation amount measuring method of the present invention, even if the sample consists of members and background parts of the members that have different reflectances, the influence of the members is reduced and the accurate positional deviation amount of the sample is measured. be able to.

Furthermore, since the optical means is constituted by a polarizing plate, it can be configured simply.

Furthermore, since the illumination means includes an optical means, normal illumination light can be used.

Further, since the illumination means uses a light source having polarized light, the optical means can be omitted, thereby simplifying the adjustment.

In addition, the position measuring means calculates the sum of the photoelectric conversion signals from the detection means in an arbitrary range, and calculates and measures the amount of positional deviation of the sample from the peak value of the calculated sum signal. Stable measurements can be performed without being affected by conditions.

In addition, the position measurement means determines the center of gravity of the photoelectric conversion signal from the detection means and measures the amount of positional deviation of the sample from the determined center of gravity position, so even if there is a peak generated in the member, it will not be affected by this. It is possible to accurately measure the amount of positional deviation of the sample.

In addition, since the detection means has an optical axis at a position that does not coincide with the reflected optical axis of the light spot image on the sample surface, which corresponds to the illumination optical axis of the illumination means, accurate position deviation of the sample can be detected without adding a polarizing plate. Amounts can be measured.

Moreover, in the positional deviation measurement method of the present invention.

A slit image is formed by a slit detection means consisting of a slit illumination means, an optical means, and a slit detection optical means on the surface of the sample consisting of members having mutually different reflectances and the background part of the members, and the slit image is Of the reflected light,
The specularly reflected light from the member and the background is attenuated, the scattered reflected light is detected and photoelectrically converted, and the position measuring means calculates and measures the amount of vertical positional deviation of the sample from the photoelectrically converted signal. In addition, the amount of positional deviation of the sample can be accurately measured without being affected by light reflected from the background.

Further, since the position measuring means calculates and measures the amount of positional deviation of the sample from the brightness and darkness of the contrast of the slit image based on the photoelectric conversion signal from the detection means, it is possible to accurately measure the amount of positional deviation of the sample.

In addition, since the slit detection means has an optical axis at a position that does not coincide with the reflected optical axis of the slit image on the sample surface, which corresponds to the illumination optical axis of the slit illumination means, it is possible to accurately detect the sample without adding a polarizing plate. The amount of positional deviation can be measured.

Furthermore, since the automatic focusing mechanism of the present invention uses the above-mentioned method for measuring the amount of positional deviation, the focal position of the sample can be determined without being affected by the presence of members with different reflectances on the surface of the sample. It can always be held in a fixed position.

Furthermore, the surface roughness measuring device of the present invention can detect positional deviations at multiple positions on the surface of a sample even if there are members with different reflectances on the surface of the sample using the above-mentioned positional deviation measuring method. By measuring, surface roughness can be measured accurately.

Furthermore, the printed circuit board pattern inspection apparatus of the present invention uses the above-mentioned positional deviation measuring method.

The amount of focal position shift on the printed circuit board can be accurately measured and corrected without the detector being affected by defocus caused by warpage, waviness, etc. of the printed circuit board.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a positional deviation position and needle measuring device which is an embodiment of the present invention, in which (a) is a configuration diagram and (b) is a configuration diagram.
2 is an explanatory diagram showing a detection signal by the detection means in a conventional device, (c) is an explanatory diagram showing a detection signal by the detection means of the present invention, and FIG. An explanatory diagram showing a misalignment needle measuring device, in which (a) is a configuration diagram, (b) is an explanatory diagram showing a detection signal by the detection means in the conventional device, and (C) is an explanatory diagram showing the detection signal by the detection means of the present invention. FIG. 3 is an explanatory diagram showing a detection signal, and FIG. 3 is an explanatory diagram showing a positional deviation position and needle measuring device which is yet another embodiment of the present invention, in which (a) is a configuration diagram, and (b) is a conventional one. An explanatory diagram showing a detection signal by the detection means in the device, (c) is an explanatory diagram showing a detection signal by the detection means of the present invention, and FIG. FIG. 5 is an explanatory diagram showing a positional deviation positioning device applied to a position measuring mechanism, and FIG. The figures are an explanatory diagram showing a positional deviation position measuring device applied to a printed circuit board pattern inspection device which is another embodiment of the present invention, FIG. 7 is an explanatory diagram showing a measuring method of the position measuring means, and FIG. 9 is an explanatory diagram showing another measuring method of the position measuring means, FIG. 9 is an explanatory diagram showing still another measuring method of the 1-position sinus means, and FIG. 10 is an explanatory diagram showing still another measuring method of the position measuring means. FIG. 11 is an explanatory diagram showing an example of a conventional positional deviation pointer measuring device, FIG. 12 is an explanatory diagram showing a detection signal by the conventional positional deviation pointer measuring device, and FIG. 13 is an explanatory drawing showing the method. An explanatory diagram showing a conventional positional deviation position measuring device, in which (a) is a configuration diagram, (b) is a diagram showing a grating image, and (c) is a diagram showing the level of the grating image in the scanning direction. That (d) is. A diagram showing a grating image when it has a pattern, (e) is a diagram showing the level of the grating image in the scanning direction when it has a pattern. 90... Light source, 92... Lens, 93... Illumination means, 94... Light spot position detection optical system, 95... Photoelectric conversion element, 96... Light spot position detection means, 97... ...Photoelectric conversion signal, 98...Position measuring means, 99,100...
- Polarizing plate, 105... Printed circuit board, 121... Optical means, 122... Light spot, 123... Detecting means, 1
26...Sample.

Claims (16)

[Claims] 1. Forming a light spot image on the surface of a sample consisting of members having mutually different reflectances and a background portion of the members by a light spot position detection means consisting of an illumination means, an optical means and a detection means,
Among the reflected light from the light point image, specular reflected light from the member and the background is attenuated, scattered reflected light is detected and photoelectrically converted,
A method for measuring the amount of positional deviation in which the amount of vertical positional deviation of the sample is calculated and measured using a position measuring means from the photoelectric conversion signal. 2. 2. The positional deviation amount measuring method according to claim 1, wherein the illumination means includes an optical means. 3. 3. The positional deviation amount measuring method according to claim 1, wherein the optical means comprises a polarizing plate. 4. 2. The positional deviation amount measuring method according to claim 1, wherein the illumination means uses a light source having polarized light. 5. The positional deviation amount measurement according to claim 1, wherein the position measuring means calculates the sum of the photoelectric conversion signals from the detection means in an arbitrary range, and calculates and measures the positional deviation amount of the sample from the peak value of the calculated sum signal. Method. 6. 2. The positional deviation measurement method according to claim 1, wherein the position measuring means determines the center of gravity of the photoelectric conversion signal from the detection means, and calculates and measures the amount of positional deviation of the sample from the determined position of the center of gravity. 7. 2. The positional deviation amount measuring method according to claim 1, wherein the detection means has an optical axis at a position that does not coincide with the reflected optical axis of the light spot image on the sample surface, which corresponds to the illumination optical axis of the illumination means. 8. A slit image is formed on the surface of the sample consisting of members having mutually different reflectances and the background portion of the member by a slit detection means consisting of a slit illumination means, an optical means and a slit detection optical means, and a slit image is formed from the slit image. Of the reflected light, the regular reflected light from the member and the background is attenuated, the scattered reflected light is detected and photoelectrically converted, and the position measuring means calculates the amount of vertical positional deviation of the sample from the photoelectrically converted signal. A method for measuring the amount of positional deviation. 9. 9. The positional deviation amount measuring method according to claim 8, wherein the optical means is constituted by a polarizing plate. 10. 9. The positional deviation measurement method according to claim 8, wherein the slit illumination means uses a light source having polarized light. 11. 9. The positional deviation amount measuring method according to claim 8, wherein the position measuring means calculates and measures the positional deviation amount of the sample from the contrast of the slit image based on the photoelectric conversion signal. 12. 9. The positional deviation measurement method according to claim 8, wherein the slit detection means has an optical axis at a position that does not coincide with the reflected optical axis of the slit image on the sample surface, which corresponds to the illumination optical axis of the slit illumination means. 13. 9. The positional deviation amount measuring method according to claim 8, wherein the slit detection means uses a conversion element sensitive only to scattered light. 14. An automatic focusing mechanism using the positional deviation measurement method according to claim 1 or 8. 15. A surface roughness measuring device using the positional deviation amount measuring method according to claim 1 or 8. 16. A pattern inspection device using the positional deviation amount measuring method according to claim 1.