JPH05232042A - Surface inspecting method and device thereof - Google Patents

Abstract

PURPOSE:To inspect/determine a foreign matter remaining on the surface of a contact point relay with high sensitivity by radiating excitation light in a visible ultraviolet area to a relay contact point part, and measuring excitation light intensity and fluorescent intensity generated from a radiation area. CONSTITUTION:Excitation light 11 from a light source 1 is radiated to a relay contact point part. Fluorescent intensity of a relay contact point cleaned beforehand is evaluated as a reference. While monitoring (4) the fluorescent intensity and excitation light intensity at respective measurement points, a movable pulse stage 7 is scanned. When an organic foreign matter is adhered to the relay contact point part being an inspection object, its existence can be confirmed by detecting (6) fluorescence generated from the organic foreign matter due to excitation radiation. A relative quantity of residue is evaluated (8) by a value obtained by carrying out an operation on the fluorescent intensity and the excitation light intensity. When the organic foreign matter is already known, a determination (8) of the organic foreign matter is carried out by setting a value obtained by evaluating a correlation between a quantity (film thickness) of the molecular weight and the fluorescent intensity while using the excitation light intensity as a parameter, as a reference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface inspection method and apparatus for inspecting the cleanliness of a contact relay surface.

[0002]

2. Description of the Related Art Up to now, the evaluation method of the cleanliness of a contact relay has generally been a surface observation with a metal microscope, and a more detailed surface analysis has been carried out by an instrumental analysis such as EPMA. However, if there is a uniform thin film on the surface,
The observation by epi-illumination is not enough to recognize it,
Instrumental analysis requires skill in operation.

[0003]

By the way, since it is expected that various oils used in the pressing process, organic substances derived from the human body, contamination during storage, etc. are present on the surface of the contact relay, it is difficult to detect the organic substances. And effective measurement method is desired. Also,
In the evaluation, data with sufficient quantitativeness regarding organic contamination on the substrate surface is required. Although there have been examples of using fluorescence for the detection of organic substances, the significance of performing comparison between measurement data was insufficient because the excitation light intensity was not monitored as needed in the conventional device. .. Further, even when the fluorescence distribution is measured over a wide range by operating the sample setting stage, the quantitativeness may be greatly impaired due to the fluctuation of the light source. When the degree of organic contamination and finally the reliability of the product are determined by the conventional method, there is a big problem in the reliability of the quantitative evaluation. Further, when fluorescence is detected coaxially with the excitation light irradiation optical path, the higher the reflectance and the smoothness of the evaluation substrate surface, the more stray light generated by reflection of the excitation light increases, resulting in a decrease in S / N of the fluorescence detection element. Therefore, it becomes impossible to detect fluorescence with high sensitivity using a mirror-like substrate. On the other hand, from the viewpoint of product management, a simple and highly sensitive inspection device that is easy to introduce into the production line is desired. In view of such problems, an object of the present invention is to provide an inspection method and apparatus effective for inspecting the cleanliness of the contact relay surface.

[0004]

The present invention provides a method for inspecting the surface of a contact relay for dirt, wherein the relay contact portion is irradiated with excitation light in the visible and ultraviolet regions, and the excitation light intensity and the sample of the excitation light are used. The surface inspection method is characterized in that the distribution state and the amount of the foreign matter existing on the relay contact surface are evaluated by measuring the fluorescence intensity generated from the irradiation region of the relay contact.

An apparatus for performing the method is also
Excitation light source that emits excitation light in the visible and ultraviolet regions, a power meter for monitoring the intensity of the excitation light emitted from the excitation light source, a sample setting stage for setting a sample, and an irradiation region of the excitation light to the sample It is provided with means for transmitting only fluorescence of a specific wavelength and a photodetection element for detecting the transmitted light, and the sample setting stage has means for moving the substrate up and down, front and back and left and right. To do. Here, it is preferable that the present apparatus further comprises means for changing the excitation light irradiation angle with respect to the substrate installation surface, and that the photodetector is arranged in the vertical direction of the sample installation surface with respect to the excitation light irradiation spot of the sample. And

[0006]

In the present invention having the above-mentioned means, since it is a method of detecting light, the detection sensitivity to the organic residue having a light emitting property is extremely high, and the quantitative evaluation is performed by measuring the fluorescence intensity with respect to the excitation light intensity. It is possible.
Further, the distribution of organic foreign matter can be quantitatively evaluated by moving the substrate vertically and horizontally. Furthermore, when the excitation light projection axis and the fluorescence reception axis are different, the effect of stray light caused by reflection of the excitation light on the sample surface can be eliminated.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. (1) FIG. 1 is a configuration diagram of an apparatus when a photomultiplier tube is used as the fluorescence detection element 6 and a dichroic mirror 9 having wavelength characteristics of excitation light reflection fluorescence transmission for projection of excitation light is used.
In FIG. 1, the inspection apparatus includes a light source 1, a bandpass filter 2, an excitation beam splitter 3, an excitation light intensity monitor element 4, an excitation light cut filter 5, a fluorescence detection element 6, and a movable sample setting device. It comprises a pulse stage 7 and a control and data processing device 8.

The light source 1 is preferably a monochromatic light such as a laser, but may be a lamp light source having an intensity in the visible-ultraviolet wavelength range and having a wavelength selected. The excitation light wavelength selection bandpass filter 2 uses a non-fluorescent interference filter when irradiating the excitation light source 1. Excitation light cut filter 5
Is for removing the excitation light and selecting only the fluorescence generated from the sample, and uses a non-fluorescent interference filter for the excitation reflection light. The fluorescence detection element 6 is the interference filter 5
The detection element 6 is for detecting the light selected by, but the dark current reduction measures such as the cooling photomultiplier tube and the cooling CCD are taken. By constantly monitoring the change of the pumping light output by the pumping light intensity monitoring element 4, the fluctuation of the pumping light output and the deterioration of the light source are detected, and indispensable data can be obtained in the quantitative evaluation. Estimating the relative amount of organic foreign matter in each measurement region with high reliability by synchronizing the capture of this excitation light output with the capture of the fluorescence intensity by the fluorescence detection element 6 and the step of the movable pulse stage 7. Is possible.

(2) FIG. 2 shows a measurement example when the dichroic mirror 9 is not used in the above (1).
Incident angle adjusting mirror 1 instead of dichroic mirror 9
The excitation light is irradiated onto the sample 10 by 2 with an inclination angle, for example, at an incident angle of 45 degrees. Excitation light 1
The fluorescence generated from the sample by the irradiation of 1 is detected by the fluorescence detection element 6 with respect to the excitation spot from the vertical direction of the sample installation surface. The baffle 13 is installed so that the reflected light on the sample surface passes, and the scattered light and the stray light induced by the scattered light are removed. The mirror 12 is attached to a flexible arm, and the sample irradiation angle is adjusted by this.

Next, the operation of this embodiment will be described. First, the relay 10 is installed on the pulse stage 7. next,
Bandpass filters 2 and 5 suitable for the wavelengths to be excited and detected are installed. Then, the excitation light 11 from the light source 1 is applied to the relay contact portion. The fluorescent intensity of the relay contact, which has been thoroughly cleaned in advance, is used as a reference for evaluation. The movable pulse stage 7 is scanned while monitoring the fluorescence intensity and the excitation light intensity at each measurement point. When the organic foreign matter is attached to the relay contact portion to be inspected, its presence can be confirmed by detecting the fluorescence generated from the organic foreign matter due to the irradiation of the excitation light. Further, the relative amount of the residue is evaluated by the value obtained by calculating the fluorescence intensity and the excitation light intensity. When the species of organic foreign matter is known, the quantity of organic foreign matter is quantified by using the correlation between the amount (film thickness) of the molecular species and the fluorescence intensity evaluated with the excitation light intensity as a reference. FIG. 3 is an explanatory diagram showing an example in which the fluorescence intensity distribution of the relay contact portion measured by the present device is displayed in monochrome gray scale. In the figure, in the mapping diagram, the white portion shows the fluorescence intensity at the same level as the reference, and shows that the fluorescence intensity increases as it becomes darker.

[0011]

As described above, according to the surface inspection method and apparatus of the present invention, the foreign matter remaining on the surface of the contact relay can be inspected and quantified with high sensitivity.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram of an optical system used in an embodiment of the present invention.

FIG. 3 is a diagram showing an example of mapping of fluorescence intensity according to the present invention.

[Explanation of symbols]

 1 Light Source 2 Excitation Light Bandpass Filter 3 Excitation Beam Splitter 4 Excitation Light Intensity Monitor Element 5 Excitation Light Cut Filter 6 Fluorescence Detection Element 7 Movable Pulse Stage for Sample Installation 8 Control and Data Processing Device 9 Dichroic Mirror 10 Sample (Contact Relay) 11 Excitation Light 12 Incident Angle Adjustment Mirror 13 Baffle

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Claims (3)

[Claims] 1. A method for inspecting dirt on the surface of a contact relay, which comprises irradiating the relay contact portion with excitation light in the visible and ultraviolet regions, and the excitation light intensity and the fluorescence intensity generated from the irradiation region of the excitation light to a sample. A surface inspection method characterized by evaluating the distribution state and the amount of foreign matter existing on the relay contact surface by measuring. 2. An apparatus for inspecting dirt on the surface of a contact relay, wherein an excitation light source that emits excitation light in the visible and ultraviolet regions, a power meter for monitoring the intensity of the excitation light emitted from the excitation light source, and a sample are installed. A sample setting stage,
Means for transmitting only fluorescence of a specific wavelength generated from the irradiation region of the excitation light to the sample, and a photodetection element for detecting the transmitted light, the sample setting stage, the substrate up and down, front and back and A surface inspection apparatus having a means for moving to the left and right. 3. The surface according to claim 2, further comprising means for changing the excitation light irradiation angle with respect to the substrate installation surface, and the photodetector is arranged in a direction perpendicular to the sample installation surface with respect to the excitation light irradiation spot of the sample. Inspection equipment.