JPS5940148A - Inspecting apparatus - Google Patents

Abstract

PURPOSE:To eliminate the possibility of detecting a transparent flaw as a defective part even if the transparent flaw is found on a material to be inspected, by providing an optical means such as a hemispherical mirror to the irradiating side of scanning light for said material. CONSTITUTION:When a transparent flaw A exists on a material to be inspected such as a photomask for printed board 5 consisting of a light-transmittable unpatterned part and a light-untransmittable patterned part, a large portion of light components is returned to a photodetection system 6' by a hemispherical mirror 10 even when a part of scanning light is diffused to the opposite side of the system 6' at the time of carrying out sweep irradiation of the scanning light to the flaw A. Thereby, the output signal of a photodetector 6 of the system 6' is made larger than a slice level set up for its output signal and the possibility of detecting the transparent flaw as a defective part is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) 9. Technical Field of the Invention The present invention relates to an inspection apparatus provided with means for detecting transparent scratches that may occur in food to be tested as defects.

(2) Background of the Technology In order to detect defects that may occur in a photomask for a printed board, the photomask is scanned with a laser beam to inspect whether or not there is a defect. This type of device sweeps laser light along the photomask surface and detects the transmitted laser light with a photodetector, so if there is a transparent scratch on the photomask, This has the drawback of erroneously detecting this as a defective part, which causes inconvenience in photomask inspection.Therefore, there is a need for the development of a means that can provide a technical solution to this problem.

(3) Prior Art and Problems/Points In the conventional inspection apparatus of this kind, as shown in FIG. The light is connected in a sweeping manner and the transmitted light is detected by a photodetector 6. Therefore, photomask 5
The pattern formed in is as shown in (2-1) in Fig. 82 (the shaded area is the pattern part),
If there is a transparent scratch A between the patterns, when this transparent scratch A is irradiated with laser light, the laser light will be transmitted to the transparent scratch A.
However, as shown in FIG. 3, a phenomenon of diffusion occurs. As a result, the amount of light reaching the photodetector 6 decreases, and the output signal of the photodetector 6 becomes as shown in (2-2 in FIG. 2).
As shown in FIG. 2, since the output signal falls below the slice level set for this output signal, the transparent scratches are inconveniently detected as defects such as black dots.

(4) Purpose of the Invention The present invention was devised in view of the drawbacks of the conventional apparatus as described above. The objective is to provide the inspection equipment that has been developed to jp.

(5) Structure of the Invention The object is to generate a relative motion between the scanning light and the test food consisting of a translucent non-patterned portion and a non-transparent patterned portion. In an apparatus for inspecting the above-mentioned object to be inspected by receiving it with a light detection system, the above-mentioned
This is achieved by providing an optical means on the irradiation side of the scanning light for returning diffused light from transparent scratches that may occur on the object to be inspected to the light detection system.

(6) Embodiments of the Invention Hereinafter, embodiments of the present invention will be described with reference to the glazed drawings.

FIG. 4 shows the main structure of the apparatus of the present invention. This device is the first
The scan lens 3 of the device and the photomask for the print board are inspected! Between +'/+5, inspected')1
A light detection system (including a photodetector 6) detects diffused light from transparent scratches that may occur on the object to be inspected on the side where the scanning light B is irradiated onto the object to be inspected 5, that is, on the side of the scan lens 3 of the object to be inspected. 6'
The main part thereof is provided with an optical means lO for returning the light. The optical means 10 is, for example, a hemispherical mirror having a translucent portion, such as a slit, through which the scanning light B can pass over the range over which the scanning light B is swept.

According to such a configuration, the problems described in the above-mentioned conventional device can be solved as much as possible. In other words, the light-transmitting non-pattern portion and the non-light-transmitting pattern portion, such as the photomask 5 for printed board, can be solved as much as possible. Transparent scratch A (5th
See (5-1) in the diagram. In this (5-1), the shaded area is a non-transparent pattern area. ) is heated and the scanning light is swept there, and even if a part of the scanning light is diffused to the side opposite to the light detection system 6' as shown by the dotted line in Fig. 4, the light is Most of the components are returned by the hemispherical mirror 10 towards the light detection system 6'. As a result, the output signal of the photodetector 6 of the photodetector system 6' becomes larger than the slice level set for the output signal, as shown in (5-2) in FIG. There is no possibility that transparent scratches will be detected as defects as in the case of a device.

(7) Effects of the Invention As described above, the present invention provides an advantageous effect on the object to be inspected by providing a university means such as a hemispherical mirror on the side where the scanning light is irradiated onto the object to be inspected. Even if there is a transparent scratch on the surface, there is no possibility of detecting the transparent scratch as a defective part.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a conventional device, FIG. 2 is a diagram for explaining the operation of the device shown in FIG. 1, FIG. 3 is a diagram showing a state of light diffusion in a transparent scratch, and FIG. A diagram showing the main part configuration of the device,
FIG. 5 is a diagram for explaining the operation of the apparatus shown in FIG. 4. In the figure, B is the scanning light! Mj: Test food, (jJ is a light detection system, 10 is an optical means. Patent applicant: Fujitsu Ltd.

Claims (1)

[Scope of Claims] 1) A method that causes relative movement between the scanning light and an object to be inspected consisting of a light-transmitting non-patterned portion and a non-light-transmitting patterned portion, and the transmitted light is received by a light detection system. In the apparatus for inspecting the object to be inspected, an optical system is provided on the side of the object to which the scanning light is irradiated, and an optical system that returns diffused light from transparent scratches that may occur on the object to the light detection system. An inspection device characterized by being provided with means. 2) The inspection apparatus according to claim 1, wherein the optical means is a hemispherical mirror having a translucent portion that allows the scanning light to pass through the range where the scanning light is swept. .