JPS61260147A - Device for inspecting surface defect - Google Patents

Abstract

PURPOSE:To detect precisely defects by receiving reflected and transmitted light beams from a subject to be inspected and separating the penetrating part and existing part of the subject to be inspected. CONSTITUTION:The laser beam of a laser spot beam scanning part 1 is reflected by a semi-transparent mirror 2, and scans the surface of the subject to be inspected 5. The laser beam 1b reflected on the surface passes through the mirror 2 and makes incident on a reflected light receiving part 3. On the other hand a laser beam 1c passing through the penetrating part of the subject to be inspected 5 makes incident on a transmitted light receiving part 4. The transmitted light beam 1c and the reflected light beam 1b are converted into electrical signals by photoelectrical converting parts 8 and 6. A synchronizing signal 7a takes synchronization in a separation processing part 9, and a reflected light signal 6a and a transmitted light signal 8a are added to output a signal 9a available from separating the penetrating part. Then the signals 7a, 8a and 9a are inputted to an edge removing part 10 to output a defect signal 10a. In a deciding circuit 11 the signal 10a is inputted and compared with a comparison reference signal, which detects a part becoming a low level as a defect. Accordingly even when the subject to be inspected has a penetrating part, defects can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a surface defect inspection device for an object to be inspected using a laser scanning method.

[Conventional technology]

FIG. 2 is a block diagram showing a conventional surface defect device. In the figure, 1 is a laser spot light scanning unit, 2 is a semi-transparent mirror, 5 is an object to be inspected, 3 is a laser beam 1a from the laser spot light scanning unit 1 is reflected by the semi-transparent mirror 2, and 3 is an object to be inspected. This is a reflected light receiving section that receives the laser beam 1b that has been reflected by the semi-transparent mirror 2 and passed through the semi-transparent mirror 2 again. Further, 6 is a photoelectric conversion unit that converts the Raded light received by the reflected light receiving unit 3 into an electrical signal, and 12 is a defect detection unit that detects defects on the surface of the object to be inspected 50 from the electrical signal converted by the photoelectric conversion unit 6. It is.

Next, the operation will be explained. Laser spot light scanning section 1
The laser beam 1a from is reflected by the semi-transparent mirror 2 and scans the surface of the object to be inspected 5 with a constant spot diameter, and the reflected light is reflected by the semi-transparent mirror 2.
The reflected light enters the reflected light receiving section 3 through the reflected light. The incident reflected light is converted into an electrical signal by the photoelectric conversion unit 6 and sent to the defect detection unit 12.
Input 1C.

Here, if there is no defect on the surface of the object to be inspected 5, the surface is flat, and most of the reflected light will be transmitted to the reflected light receiver 3.
When the photoelectric conversion unit 6 is scanned between 5a and 5b shown in FIG. 3, the output from the photoelectric conversion unit 6 is a signal shown as 5C. Furthermore, if there is a defect 13 such as a scratch or a foreign matter adhering to the surface, the output from the photoelectric converter 6 becomes a signal indicated by 5f, and the signal level at the defect 13 portion decreases.

Such scanning signals 5c and 5f are input to the defect detection section 12, and the defect detection section 12 compares them based on the comparison reference value signal 5j every time the laser spot beam is scanned. Detect the level part as a defect.

[Problem that the invention seeks to solve]

The conventional surface defect inspection device is configured as described above, and detects as a defect a portion where the level of the scanning signal 5C on a normal surface is lower than the comparison reference signal 5j.
As shown in the figure between 5g and 5h, the scanning signal is as shown in 51 for the object 5 to be inspected which has a piercing portion 14 such as a punched portion. Therefore, there is a problem in that it is impossible to distinguish between the penetrating portion 14 and the defect 13, and that it is impossible to inspect the object 5 to be inspected having such a penetrating portion 14.

Jin's invention was made in order to solve the above problems, and the purpose is to obtain a surface defect inspection device that can accurately detect defects even in objects to be inspected that have penetration parts. do.

[Failure to solve the problem]

The surface defect inspection device according to the present invention includes a reflected light receiving section that receives reflected light from an object to be inspected, a transmitted light receiving section that receives passing radar spot light, and a surface defect inspection device that detects an object to be inspected based on output signals thereof. a separation processing unit that distinguishes between a penetrating part and an existing part of the object; an edge removal unit that removes a signal from an edge part of the object to be inspected and outputs a defect signal; The defect determining unit is also equipped with a defect determination unit for detecting defects.

[For production]

In the surface defect inspection apparatus of the present invention, reflected light and transmitted light from the object to be inspected are received, the separation processing section separates the penetrated part and the existing part of the object to be inspected based on these signals, and further The edge removal section removes the edge portion and detects only the defect signal on the existing portion.

〔Example〕

FIG. 1 is a diagram showing the configuration of a surface defect inspection apparatus according to an embodiment of the present invention. In the figure, 1 is a laser spot light scanning unit similar to the conventional device, 1a is a laser beam, and 2
3 is a semi-transparent mirror, 3 is a reflected light receiver configured with an array fiber (or optical lens), 4 is a transmitted light receiver configured in the same manner as the reflected light receiver 3, 5 is an object to be inspected, 6, 7 ．．
8 are photoelectric converters for converting the signal from the reflected light receiver 3, the reference light signal for synchronization, and the signal from the transmitted light receiver 4 into electrical signals, and 6a and 7a8a are photoelectric converters, respectively. These are a reflected light signal, a synchronization signal, and a transmitted light signal output from the converters 6, 7, and 8.

Furthermore, 9 is a separation processing unit for determining and separating the penetration portion 14ft of the object to be inspected 5 from the reflected light signal 6a based on the transmitted light signal 8a, and 10 is the penetration portion 14 of the object to be inspected 5 shown in FIG. Since light is scattered at the edge portion which is the boundary between
an edge removal unit that removes the edge portion based on a;
Reference numeral 11 denotes a defect determination unit that determines defects from the signals after these processes.

Next, the operation of the surface defect inspection apparatus having the above configuration will be explained. The laser beam 1a emitted multiple times by the laser spot light scanning unit 1 is reflected by a semi-transparent mirror 2 and scans the surface of the object to be inspected 5, and the laser beam 1b reflected from this surface is transmitted through the semi-transparent mirror 2 and becomes reflected light. The light is incident on the light receiving section 3. On the other hand, the laser beam 1c that has passed through the penetrating portion 14 of the object to be inspected 5 is transmitted to the transmitted light receiving section 4.
The transmitted light 1c and the reflected light 1b are converted into a tortoise signal tic by the photoelectric converters 8 and 6. Further, in order to obtain a synchronizing signal for each scan used in the separation processing section 9, the laser beam 1a that directly passes through the semi-transparent mirror 2 is converted into an electric signal by the photoelectric conversion section 7.

Here, as shown in FIG.
and defect 13, the reflected light signal 6a and transmitted signal 8a input to the separation processing section 9 are as shown in the figure. Then, this separation processing section 9 synchronizes based on the synchronization signal 7a, and when the reflected light signal 6a and the transmitted light signal 8& are added, the penetration portion 1.4'? : Output the separated signal 9a. The ethos removal unit 10 inputs the signal 9a, the synchronization signal 7a, and the transmitted light signal 8a output from the separation processing unit 9, and enlarges the transmitted light signal 8a by signal processing to generate a signal 8a.
By generating signal b and adding it to signal 9a, defect signal 10a is output. Further, the defect determination section 11 inputs the defect signal 10a and generates a comparison reference value signal (Fig. 3 (5j
)), and a portion whose level is lower than this comparison reference signal 5j is detected as a defect.

In the above embodiment, the semi-transparent mirror 2'a- is used to receive specularly reflected light, but this semi-transparent mirror 2'a- is replaced with a total reflective mirror, and a laser beam is irradiated from an oblique direction to receive specularly reflected light. Alternatively, a similar effect can be obtained by a method of receiving scattered light from a defective portion.

〔Effect of the invention〕

As described above, according to the surface defect inspection device of the present invention, the reflected light and the passing light from the object to be inspected are detected and the penetrating portion and existing portion thereof are separated. Even in cases where there are no through parts, defects can be detected in the same way as in cases where there are no through parts, making it possible to inspect objects to be inspected that were previously impossible to inspect. .

This has a great effect on, for example, IC lead frame inspection.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a surface defect inspection device according to an embodiment of the present invention, FIG. 2 is a diagram showing the configuration of a conventional surface defect inspection device, and FIG. 3 is a diagram showing the structure of a conventional surface defect inspection device. FIG. 4 is a diagram showing scanning of an object to be inspected and the waveform of its output signal in a surface defect inspection apparatus according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Laser spot light scanning part, 3... Reflected light receiving part, 4... Transmitted light receiving part, 5... Inspection object, 5j.
...Comparison reference value signal, 6a...Reflected light signal, 8a...
- Transmitted light signal, 9... Separation processing section, 10... Esso removal section, 10a... Defect signal, 11... Defect determination section. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] Surface defect inspection that irradiates the surface of the object to be inspected with a laser spot light from a laser spot light scanning unit and scans it, detecting surface defects by using the difference in the amount of reflected light between the normal surface and defective surface of the object to be inspected. In the apparatus, a reflected light receiving section that receives reflected light from the object to be inspected, a transmitted light receiving section that receives the laser spot light that passes through the object to be inspected, and from these reflected light receiving section and transmitted light receiving section. a separation processing unit that discriminates between a penetrating portion and an existing portion of the object to be inspected based on a reflected light signal and a transmitted light signal corresponding to the output of the separation processing unit; an edge removal unit that removes an edge portion that is a boundary between a penetrating portion and an existing portion of the object to be inspected based on the inspection object and outputs a defect signal, and detects a defective portion by comparing this defect signal with a comparison reference value signal. A surface defect inspection device comprising: a defect determination section.