JPH05196568A - Plated metal inspection device - Google Patents

Abstract

PURPOSE:To enable inspection of plated metal capable of reducing cost to be conducted without any high accuracy parts by receiving reflection light with wave length having a specific difference in reflectivities of the metal underneath and the plated metal. CONSTITUTION:The light from a light source 101 condensed with a condenser lens 102 and guided on an optical fiber 103 passes a filter 201 and goes into a coaxial scattering lighting device 104. The lighting light is reflected on a half mirror 105 and lights a measured object 106. The light beam reflected by the measured object 106 focuses image on a light receiving surface of a video-camera 108 owing to the lens group of a microscope. The output 108 image signal 109, that is, the reflection light of wave length having a specific difference in reflectivities of the metal underneath and the plated metal, for example, signal based on the reflection light image of wave length between 400nm and 450nm is processed in a signal processing circuit 112. By this, plated part is extracted out of the brilliancy of the input data, position information and defects of the plated metal are detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating inspection apparatus for measuring the position or area of plating and inspecting the same, and more particularly to an improvement of an apparatus for inspecting an inspection object made of copper and copper alloy.

[0002]

BACKGROUND ART When an image processing apparatus is to be used for automating a plating inspection, the following method can be used. First, a description will be given with reference to FIG. The light collected from the halogen bulb light source 101 by the condenser lens 102 and guided by the optical fiber 103 is reflected by the half mirror 105 incorporated in the coaxial epi-illumination device 104, and illuminates the DUT 106. DUT 10
No. 6 is copper plated with silver. The light beam reflected by the DUT 106 is refracted by the lens group 107 of the microscope and forms an image on the light receiving surface of the video camera 108 at an appropriate magnification. Image signal 10 output from the video camera after that
9 enters the image processing device 114, the analog-digital (A / D) converter 110 is controlled by the control circuit 113.
After being A / D-converted and stored in the memory circuit 111, the signal is input to the signal processing circuit 112. Signal processing circuit 1
Reference numeral 12 extracts the plated portion from the brightness of the input data, and performs the plating position information, defect detection, and the like.

[0003]

However, when the apparatus as described above is used, the difference in the reflectance between the copper ground portion and the plated portion is small, so that it is possible to distinguish the small difference with high accuracy. An A / D converter is required. As a result, the cost of the device increases.

Therefore, an object of the present invention is to provide a plating inspection apparatus which does not require high-precision parts and which can reduce costs.

[0005]

According to the present invention, in order to obtain a predetermined judgment result even if the cost is reduced without using high-precision parts, the color of the metal is different from that of the metal. The irradiation means for irradiating the plated sample, the light receiving means for receiving the reflected light of the sample, and the judging means for judging the position or area of the plating based on the received light image of the light receiving means. The light receiving means provides a plating inspection device for receiving reflected light having a wavelength having a predetermined difference between the reflectance of the metal and the reflectance of the plating, and the sample is copper or copper alloy. When silver, tin, or white metal plating is applied, the irradiation means is 400 nm to 4 nm.
The sample may be illuminated through a filter that transmits light at a wavelength of 50 nm, or at 458 nm or 477.
The sample may be emitted by an argon ion laser that emits light having a wavelength of nm. On the other hand, when a normal irradiation means is used as the irradiation means, the light receiving means is 400 n
The reflected light of the sample may be received through a filter that transmits light having a wavelength of m to 450 nm.

[0006]

The reflected light having a wavelength having a predetermined difference between the reflectance of the bare metal and the reflectance of the plating, for example, 400 nm to 450 n
A signal based on the reflected light image of the wavelength m is processed by the signal processing circuit. The reflectance of copper of the wavelength of 400 nm to 450 nm is 5 dB to 11 d more than that of silver.
B is low, which causes an easily discriminating difference in the level of the received light signal of the reflected light. This difference creates a margin in the design of the signal processing circuit, and a highly accurate determination result can be obtained.

[0007]

First Embodiment A first embodiment of the present invention will be described in detail with reference to FIG. The light collected from the halogen light bulb light source 101 by the condenser lens 102 and guided by the optical fiber 103 passes through the filter 201 installed in the light incident part of the coaxial epi-illumination device 104 and transmitting the light in the vicinity of 400 nm to 450 nm. , And becomes bluish light and enters the coaxial epi-illumination device 104. The illumination light is emitted from the half mirror 105 built in the coaxial incident illumination device 104.
Is reflected by and illuminates the DUT 106. The DUT 106 is copper plated with silver. DUT 10
The light beam reflected by 6 is imaged on the light receiving surface of the video camera 108 by the lens group 107 of the microscope at an appropriate magnification. Image signal 109 output from video camera 108
When it enters the image processing device 114, it is A / D converted by the analog-digital (A / D) converter 110 under the control of the control circuit 113, stored in the memory circuit 111, and then input to the signal processing circuit 112. . Signal processing circuit 11
2 extracts the plated part from the brightness of the input data,
Position information of plating or detection of defects is performed.

FIG. 2 is a spectrum diagram of reflected light of copper and a spectrum diagram of reflected light of silver in the A / D converter 110. It can be seen that the reflectance of copper is about 5 dB lower near 450 nm and about 11 dB lower than about 400 nm as compared to silver, so that the filter 201 that transmits light near 400 nm to 450 nm is installed in the coaxial epi-illumination device 104.
It is located in the light entrance part of. Since the light reflected from the copper part is dark and the light reflected from the plated part is bright, there is a strong contrast, so even if the same A / D converter as the conventional one is used, the difference in voltage level will be large. It is possible to obtain image data that allows the plated portion to be easily identified.

[0009]

Second Embodiment A second embodiment of the present invention will be described with reference to FIG. The light collected from the halogen bulb light source 101 by the condenser lens 102 and guided by the optical fiber 103 is reflected by the half mirror 105 incorporated in the coaxial epi-illumination device 104 to illuminate the DUT 106. The light beam reflected by the DUT 106 has a blue transmission filter 301 having characteristics equivalent to those of the optical filter.
After passing through, the image is formed on the light receiving surface of the video camera 108 at an appropriate magnification by the lens group 107 of the microscope. After that,
Since the operation is exactly the same as in the first embodiment, the details are omitted.

In the second embodiment, in order to remove the red component having a long wavelength from the reflected light, the reflected light component incident on the video camera 108 is only the blue light ray, just as in the first embodiment. Therefore, the same effect as that of the first embodiment can be obtained.

[0011]

Third Embodiment A third embodiment of the present invention will be described with reference to FIG. The beam expander 4 converts the light of 458 or 477 nm generated from the argon ion laser 401.
After expanding the luminous flux by 02, the coaxial epi-illumination device 104
And illuminates the DUT 106. After that, the same operation as that of the first embodiment of the present invention is performed, and thus the details are omitted.

As described above, according to the plating inspection apparatus of the present invention, since light of a wavelength having a predetermined reflectance difference between the metal and the plating is used, the metal and the plating part are used. Can increase the contrast. Therefore, the plated portion is surely recognized, and the device can be configured without using a highly accurate A / D converter, so that the highly accurate device can be configured at low cost.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a first embodiment of a plating inspection apparatus of the present invention.

FIG. 2 is a graph showing measurement results of spectral characteristics of reflected light of copper and silver.

FIG. 3 is an explanatory diagram showing a second embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a third embodiment of the present invention.

FIG. 5 is an explanatory view showing a conventional plating inspection device.

[Explanation of symbols]

Reference Signs List 101 halogen light source 102 condenser lens 103 optical fiber 104 coaxial epi-illumination device 105 half mirror 106 DUT 107 microscope lens group 108 video camera 109 image signal 110 analog-digital (A / D) converter 111 memory circuit 112 signal processing Circuit 113 Control circuit 114 Image processing device 201 Filter 301 Filter 401 Argon laser device 402 Beam expander

Claims (4)

[Claims] 1. An irradiation means for irradiating a sample in which a metal is plated with a color different from the color of the metal, a light receiving means for receiving the reflected light of the sample, and a light receiving image of the light receiving means. A light receiving means for receiving reflected light of a wavelength having a predetermined difference between the reflectance of the base metal and the reflectance of the plating. Characteristic plating inspection device. 2. The irradiation means is 400 nm to 450 nm.
The plating inspection apparatus according to claim 1, wherein the sample is irradiated through a filter that transmits light having a wavelength of nm, and the sample is formed by plating copper or copper alloy with silver, tin, or white metal. 3. The irradiation means is 458 nm or 4
The plating test according to claim 1, wherein the sample is irradiated with an argon ion laser that emits light having a wavelength of 77 nm, and the sample is formed by plating copper or a copper alloy with silver, tin, or a white metal. apparatus. 4. The light receiving means is 400 nm to 450 nm.
The plating according to claim 1, wherein reflected light of the sample is received through a filter that transmits light having a wavelength of nm, and the sample is formed by plating copper or copper alloy with silver, tin, or white metal. Inspection equipment.