JPH0933237A - Measuring probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a measuring probe by which measured data suitable for the many-sided evaluation of a face to be measured is detected efficiently. SOLUTION: The measuring probe is provided with an optical detection part 100 adopting an astigmatism method, and a capacitance-type detection part 200 whose constitution is similar to that of a capacitance-type displacement meter. Two electrode parts 202a, 202b for capacitance detection are formed in a concentric circle shape on the sensor face 201 of the capacitance-type detection part 200, and a hole 201a which has a proper diameter is opened so as to pass their center. Then, in a measurement, the measuring light of the optical detection part 100 passes the hole 201a, and a region D on the surface of an object A to be measured, which is contained in the measuring range C of the capacitance-type detection part 200, is illuminated. Consequently, the surface roughness of the object A to be measured is measured by the optical detection part 100 by one scanning operation, and the shape of an undulation or the like which is generated on the surface of the object A to be measured is measured by the capacitance-type detection part 200.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring probe suitable for measuring the surface shape and surface roughness of an object to be measured.

[0002]

2. Description of the Related Art A measuring probe of a measuring instrument for measuring the surface shape and surface roughness of an object to be measured is
It is roughly classified into a contact type and a non-contact type. In detail, the former is to detect the position of the surface of the object to be measured by bringing a probe formed of a material such as ruby into contact with the surface of the object to be measured, while the latter is to detect the position of the surface of the object to be measured. The position of the surface of the measured object is detected without contacting the surface of the measured object at all. The measuring device mentioned here is a device that moves the measuring probe relative to the object to be measured.

When performing measurement, it is general to select a more preferable measurement probe from both measurement probes in advance according to the measurement conditions and use a measuring instrument equipped with this. is there. For example, as a measuring instrument used for inspection for evaluating the performance of a mechanical element, a measuring instrument equipped with a non-contact measuring probe is often selected rather than a contact measuring probe. The main reason for this is that when a measuring instrument equipped with a contact-type measuring probe is used for such inspections, defects such as scratches occur on the surface of the mechanical element that is the object to be measured due to contact with the probe, and the inspection as a product At the stage, there is a possibility that the mechanical element itself may be a defective product, and there is a limit to the improvement of the measurement accuracy due to the restriction based on the dynamic characteristics of the measurement probe.

Among these non-contact measurement probes, an example of a frequently used probe is the position of the surface of the object to be measured by detecting the intensity of the measurement light reflected by the surface of the object to be measured. Examples include an optical measurement probe for measuring the, and a capacitance type displacement meter for measuring the position of the surface of the object to be measured by detecting a change in electrostatic capacitance between the surface of the object to be measured and the electrodes. .

[0005]

Since the non-contact type measuring probe has a preferable measuring range depending on the measuring principle adopted, the non-contact type measuring probe has a preferable non-contact type according to the purpose of the measurement in order to perform more efficient measurement. It is desirable to use forensic measurement probes. For example, when high-resolution measurement is required, such as when measuring the surface roughness of the measured object (especially,
When high resolution in the lateral direction is required), it is preferable to use a non-contact measurement probe that employs the astigmatism method, which is suitable for measuring a fine area on the surface of the DUT. When roughly measuring the surface shape of an object to be measured, it is preferable to use a capacitance displacement meter capable of measuring a relatively wide area.

[0006] By the way, since such a non-contact type measuring probe is usually incorporated in the structure of a measuring instrument, it is often inflexible in replacing the non-contact type measuring probe. Therefore, when multifaceted evaluation items are given in inspections for evaluating the performance of mechanical elements, it is necessary to prepare each measuring device that employs a non-contact type probe suitable for measurement corresponding to each evaluation item. .

This causes, firstly, an increase in equipment cost required for the inspection, secondly, causes a reduction in the work efficiency at the time of inspection, and thirdly, is performed based on the measurement data. This causes the reliability of the evaluation to decrease. The reasons that cause the second and third statements are as follows.
In such a case, for each evaluation item, the measurement object has to be positioned with respect to the measuring instrument prepared corresponding to each evaluation item, and such positioning is a troublesome work requiring skill. This is a cause of hindering the efficiency of the second work. In addition, the positioning accuracy of the object to be measured with respect to each of these measuring instruments and the measurement error caused by each measurement by each measuring instrument due to the change of the measuring environment with time are consistent between the measured data obtained by each measuring instrument. The fact that the quality is good or bad causes the reliability of the evaluation performed based on the third measurement data to be reduced.

Therefore, it is an object of the present invention to provide a measurement probe that efficiently detects measurement data suitable for multifaceted evaluation of the surface of an object to be measured.

[0009]

[Means for Solving the Problems] In order to achieve the above objects,
The present invention is a measurement probe for measuring the position of the surface of an object to be measured, irradiating the surface of the object to be measured with measurement light, and the object to be measured according to the measurement light reflected on the surface of the object to be measured. An optical detector for detecting the position of the surface of the object to be measured, and 2
A capacitance type having a sensor surface on which two electrode portions are formed and detecting the position of the surface of the measured object according to the capacitance between the two electrode portions and the surface of the measured object. A detection unit, and the sensor surface of the capacitance type detection unit is provided with the above-mentioned 2
A through hole is formed through the central part of the two electrode parts, and the optical detection part and the capacitance type detection part are the measurement light irradiated on the surface of the object to be measured and the surface of the object to be measured. There is provided a measurement probe, wherein the reflected measurement light is arranged so as to pass through a through hole on the sensor surface of the capacitance type detection unit.

[0010]

According to the measuring probe of the present invention, the capacitance type is a position of the surface of the object to be measured according to the capacitance between the two electrode parts and the surface of the object to be measured. And the optical detection unit detects the position of the surface of the measured object according to the measurement light reflected by the surface of the measured object. At this time, the measurement light irradiated on the surface of the object to be measured and the measurement light reflected on the surface of the object to be measured respectively pass through the through holes on the sensor surface of the capacitance type detection unit.

As described above, the present measurement probe employs the optical detection unit adopting the measurement principle suitable for measuring the surface roughness of the object to be measured and the measurement principle suitable for measuring the surface shape of the object to be measured. Since it also serves as a capacitance type detection unit, the measuring instrument equipped with this unit can simultaneously measure the surface roughness and surface shape of the object to be measured with one scan. You can Further, it is not necessary to position the object to be measured, which has conventionally been required to associate the measurement data obtained by each measurement. Therefore, unlike the conventional case, an error caused by such a positioning operation is not variably included in each measurement data.

Therefore, if the measuring instrument to which the main measurement probe is attached is used for inspection of mechanical elements and the like, the time required for measurement and the measurement work can be shortened, that is, the inspection work can be made efficient. Further, in the stage of evaluating the measurement result, it is possible to refer to the consistent measurement data obtained under exactly the same measurement environment condition, so that the reliability of the evaluation in the inspection is improved.

That is, according to the present measurement probe, measurement data suitable for multifaceted evaluation of the surface of the object to be measured can be efficiently detected.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, the basic structure of the measuring probe according to this embodiment will be described with reference to FIG. The measurement probe is used by being attached to a device (hereinafter referred to as a measuring instrument) that moves the measurement probe relatively to the object to be measured.

Now, the present measurement probe is similar to two detection units adopting different measurement principles, that is, an optical detection unit 100 adopting the astigmatism method as a measurement principle, and a capacitance type displacement meter. It also serves as the capacitance type detection unit 200 that adopts the measurement principle. The former is for measuring the surface roughness of the measured object A, and the latter is for measuring the measured object A.
For measuring a rough surface shape over a predetermined range (for example, undulations that periodically appear on the surface of the object A to be measured). This is mainly due to the lateral resolution of both, but the former measures the lateral resolution in the micron order with a minute area on the surface of the object A to be measured as the measurement range. On the other hand, in the latter case, the latter is capable of flexibly changing the measurement range by switching operation of the electric system similar to that of the capacitance type displacement meter. In order that the surface shape can be measured with an appropriate lateral resolution, a region having an area suitable for this is set in advance as a measurement range.

A detailed description of the well-known measurement principle adopted for the optical detection unit 100 and the capacitance type detection unit 200 will be omitted, and here, both detection units 100, which are the features of the present measurement probe, will be omitted. , 200 will be mainly described.

The optical detection unit 100 and the capacitance type detection unit 200 are arranged in such a positional relationship that the measurement range is a region including the same position B on the surface of the object A to be measured.

For this reason, two electrode portions 20 for capacitance detection are provided on the sensor surface 201 of the capacitance type detection portion 200.
2a and 202b are formed concentrically, and a hole 201a having an appropriate diameter is formed so as to pass through the center thereof. In this embodiment, the sensor surface 201 is made of an insulating material such as glass, and a conductor such as aluminum is vapor-deposited on the surface of the sensor surface 201 to form two electrode portions 202a and 202b.
Is formed.

The measuring light of the optical detecting section 100 is
By passing through the hole 201a formed in the sensor surface 201, the area D on the surface of the object A to be measured, which is included in the measurement range C of the capacitance type detection unit 200, is illuminated.

That is, in the information processing apparatus 300 shown in FIG. 2, the two electrode portions 202a and 202b of the capacitance type detection unit 200 and the surface of the object A (measurement range C) are measured.
And the electrostatic capacitance between the two are calculated, and the relative displacement amount of the surface (measurement range C) of the object A to be measured with respect to the main measurement probe is calculated based on the electrostatic capacitance.

On the other hand, in the optical detection unit 100, He-N
e The measurement light emitted from the laser oscillator 101 passes through the pinhole 103 through the condensing lens 102, and becomes λ / 4.
After a predetermined phase difference is given by the plate 104, a hole 201 formed in the sensor surface 201 of the capacitance type detection unit 200.
While passing through a, the light is focused on the surface (measurement range D) of the measured surface A by the objective lens 105. In this state, that is, when the measurement light of the optical detection unit 100 is the object A to be measured.
In the state of being focused on the surface B of the
The sensor surface 201 of No. 00 is preferably arranged such that the distance from the surface of the object A to be measured is about 1 mm, which is suitable for measurement. Now, the measurement light reflected by the surface (measurement range D) of the surface A to be measured is again provided with the hole 201a formed in the sensor surface 201 of the capacitance type detection unit 200.
After passing through, the beam enters the beam splitter 107 via the polarization beam splitter 106 and is split into two light beams. The respective measurement lights divided into these two light fluxes pass through the respective cylindrical lenses 108a and 108b, and the respective four-divided photodiodes 109a and 10b.
It is incident on 9b. Then, the information processing device 400 of FIG.
At each of the four divided photodiodes 109
The difference between the output signals from a and 109b is calculated, and based on this difference, the relative displacement amount of the surface (measurement range D) of the object A to be measured with respect to the main measurement probe is calculated. At the same time, the information processing device 400 controls the oscillation of the laser light of the He—Ne laser oscillator 101.

As described above, the present measurement probe employs the detection unit which adopts the measuring principle suitable for measuring the surface roughness of the object A to be measured and the measuring principle suitable for measuring the surface shape of the object A to be measured. Since it also serves as a detection unit, a measuring instrument equipped with the measuring unit separately measures with two measuring instruments equipped with a measuring probe that adopts a measuring principle suitable for each measurement in the conventional case. The surface roughness and the surface shape of the object A to be measured, which were necessary, can be simultaneously measured by one scanning. In addition, it is not necessary to position the object to be measured A, which is conventionally required to associate the measurement data obtained by each measurement. Therefore, if the measuring instrument equipped with the present measurement probe is used for inspection of mechanical elements, etc., firstly, it is possible to shorten the time required for measurement and the measurement work, that is, to improve the efficiency of the inspection work, Second, since the consistent measurement data obtained under the same measurement environment conditions can be referred to, the reliability of the evaluation result in the inspection is improved.

In this embodiment, the astigmatism method and the measurement principle similar to that of the capacitance type displacement meter are adopted as the measurement principles of the respective detection parts, but these measurement principles are not necessarily adopted. do not have to. For example, as the measurement principle of the detection unit for measuring the surface roughness, another measurement principle that is considered suitable for measuring the surface roughness of the object A to be measured, for example, the critical angle method, the double knife edge method, the optical heterodyne An interference method, an astigmatism method or the like may be adopted. Further, as a measuring principle of the detecting section for measuring the surface shape, a detecting section adopting the same measuring principle as that of the air micrometer or the same measuring principle as that of the eddy current displacement sensor may be used. However, no matter which measurement principle is adopted, both are arranged at a position such that the measurement range of the detection unit for surface roughness measurement is included in the measurement range of the detection unit for surface shape measurement. There is a need.

[0025]

According to the measuring probe of the present invention, the measuring data suitable for the multifaceted evaluation of the surface of the object to be measured can be efficiently detected.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of a measurement probe according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining the configuration of a measurement system using the measurement probe of FIG.

[Explanation of symbols]

100 ... Optical detection unit, 200 ... Capacitance type detection unit, 2
01 ... Sensor surface of electrostatic capacitance type detection unit, 202a, 202
b ... Electrode portion for detecting capacitance, 201a ... Hole, 101 ...
He-Ne laser oscillator, 102 ... Condensing lens, 103
... Pinhole, 104 ... λ / 4 plate, 105 ... Objective lens, 106 ... Polarization beam splitter, 107 ... Beam splitter, 108a, 108b ... Cylindrical lens, 109a, 109b ... Quadrant photodiode, 3
00 ... Information processing device, 400 ... Information processing device

Claims (1)

[Claims] 1. A measurement probe for measuring the position of the surface of an object to be measured, wherein the surface of the object to be measured is irradiated with measuring light, and the measuring probe reflects the measuring light reflected on the surface of the object to be measured. It has an optical detection section for detecting the position of the surface of the object to be measured and a sensor surface on which two electrode sections are formed, and the capacitance between the two electrode sections and the surface of the object to be measured is And a capacitance type detection unit for detecting the position of the surface of the object to be measured according to the present invention, and a sensor surface of the capacitance type detection unit has a through hole penetrating the central portions of the two electrode units. The optical detection unit and the capacitance type detection unit are formed by the measurement light irradiated on the surface of the measured object and the measurement light reflected on the surface of the measured object. The measurement probe is arranged so as to pass through a through hole on the sensor surface of the measurement probe.