JPS60108703A - Observing method of body - Google Patents

Abstract

PURPOSE:To observe the state of the surface of a body accurately, by providing a filter, on which the negative picture of the distribution of the reflected light from each part of the surface of the body is formed, between a light source and the body, projecting the light, which is passed through the filter, on the body, and performing the observation. CONSTITUTION:A filter 6, on which the negative picture of the picture of the surface of a body 5 to be observed is formed, is arranged on a path between a ground glass plate 3 and a half mirror 4. Thus the distribution of the incident light is corrected by the distribution of the reflected light, and the distribution J2 of the luminous intensity of the light, which is transmitted through the filter 6, is obtained. Therefore, the state of the surface of the body 5 can be accurately observed.

Description

Detailed Description of the Invention [Technical Field of the Invention 1] The present invention relates to a method for observing an object, and in particular a method for projecting light from an artificial light source onto the surface of an object to be observed while photographing the surface of the object using a television camera or the like. This is a description of how to observe J with 1'A equipment.

[Technical Background of the Invention 1 The appearance inspection of a resin molded semiconductor device such as a resin molded IC is carried out by irradiating the surface of the 21' diaphragm device with light from a light source and inspecting the surface of the semiconductor device with an industrial television camera. This is done by observing with photographic equipment such as (ITV). FIG. 1 shows a conventional object observation method used in the external appearance inspection of ICs and the like. In the figure, 1 is a television camera, 2 is a light source, and 3
1 is a frosted glass, 1 is a half mirror, and 15 is an observation object such as an IC. In the object observation method using such an equipment arrangement, C converts the light projected from the light source 2 through the frosted glass 3 into a parallel beam of almost uniform surface brightness, and illuminates the observation object 5 with the half mirror 4. Observation is performed by making the reflected light from the observation object 5 enter the television camera 1 through the half mirror 4.

In this way, when observing by illuminating the observation target with light from an artificial light source and using the reflected light from the observation target, in order to perform accurate observation, it is necessary to make the light incident on all places on the observation target surface. The luminous intensity of the light is equal, the light that enters the image carrier from the surface of the observation object is only specularly reflected light, and furthermore, only perfectly parallel light beams are incident on all locations on the surface of the observation object. etc., are necessary. However, in the conventional observation method using the equipment configuration shown in FIG. 1, the above-mentioned conditions were not satisfied, and positive Me observation results were not necessarily obtained.

[Issues with first-line technology +:, Il In the conventional observation method using the equipment configuration shown in Figure 1, the light surface of the light source is small, and if the power is uniform in one direction, then it is possible to Since r is small, B) reflects the non-uniformity of the incident light from the object to be measured, and L) does not represent the actual surface condition of the object to be observed.

FIG. 2 shows the luminous intensity of the light irradiated from the light source 2 in the observation method shown in FIG. There are seven shown. As can be seen from Figure 2, the luminous intensity of the light emitted from the source 2 at ) is y? Furthermore, the intensity of the light that is projected onto the observation object after passing through the crow 3 differs at various locations on the projection surface. Therefore, C
Also, the light reflected from the surface of the observation 34 object contains information based on the luminous intensity distribution of the input ray (GJ), which represents the surface state of the object, and as a result of A, the truth The surface state cannot be covered by observation.

IJI'-=
One possible solution is to make the light emitting surface of the light source sufficiently large, but this method requires the light source to be quite large, which has practical limitations (1). However, if the luminous intensity of the luminous flux incident on each part of the surface of the object is not uniform, there is a problem that it would be better if the reflected light at each part of the surface was uniform.

[Object of the Invention] An object of the present invention is to provide an object observation method that can accurately observe the surface state of an object.

[Summary of the Invention] This invention provides a method for projecting light from an artificial light source onto the surface of an object to be observed and viewing the surface of the object using a television camera or the like. 11
! 1, the method is characterized in that a filter representing the illumination surface distribution on each part of the surface of the object is interposed in the optical path between the light source and the object, and the object is irradiated with light that has passed through the filter while observation is performed. It is something to do. The filter is produced in advance using a pseudo-object of the object, but it can also be produced by simulation using an image processing device and a computer. ] FIG. 3 shows an embodiment of the method of the present invention, and in the same figure, the parts indicated by the same number -m as in FIG.
This is the same equipment as shown in the figure.

The method of the present invention is characterized in that a filter 6 representing the illuminance of the surface of the observation object 5 (7) is provided in the optical path between the half mirror 4 and the nulling glass 3. By inserting the <1 filter 6 into the optical path of the desired light, the luminous intensity distribution of the human light is made uniform, and uniform reflected light is obtained from each part of the surface of the observation object 50. I'm going to sleep.

No. 4N shows a state in which the luminous intensity distribution of the input light is changed i4 by inserting the 'filter 6 into the optical path of the input q.multidot.1 light. In the same figure, J. is the light intensity [σ distribution 1,) of the light generated from the light source 2, 11 is the luminous intensity of the light transmitted through the frosted glass 3, and J′) is the luminous intensity distribution of the light transmitted through the filter 6.

The filter 6 is a negative 1 corresponding to both images of the surface of the observed object.
The filter 6 can be manufactured by the following method, for example.

First, as shown in Fig. 5), the same surface as the surface of the observation object is subjected to EIT, and a plate-shaped pseudo observation object 7 made of the same material as the observation object is placed at the same surface as the observation object (i'/ , i
ff/, a normal camera 8 is fixed at the same position as the television camera 1, and a photograph of the surface of the pseudo observation object 7 is taken on a positive film 9 placed inside the camera 8. At this time, the half mirror 4, frosted glass 3, and light source 2 are used under the same conditions as when observing the observation object 5 with the television camera 1.

Then, as shown in FIG. 6, the positive film 9 is transferred using a light source 10 and a magnifying lens 11 to produce a negative film 12 of an appropriate size, which is referred to as a filter 6.

Since the filter 6 manufactured in this way is negative with respect to the reflection state of the surface of the observation object, by inserting this filter 6 into the optical path of the incident light, the incident light distribution can be corrected by the reflected light distribution. is generated, and from the surface of the observation object 5, there is a good Z friendly radiation that includes distortion of the incident light distribution.141
It will be done.

Note that the filter 6 Gj can be adjusted not only by the above-mentioned method but also by other methods θ.

[Effect of the invention 1] In the method of the present invention, the luminous intensity difference of the incident light is corrected according to the illuminance distribution on the surface of the observation object, so the surface of the observation object can be observed accurately. The slice level determination range when binarizing observation data has become wider, and it is possible to
1r1 becomes easier.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing a conventional method for observing an object, Figure 2 is a diagram showing the luminous intensity distribution of incident light in the conventional method shown in Figure 1, and Figure 3 is a diagram showing an object observation method according to the present invention. A schematic diagram showing the method, Figure 1 shows the luminous intensity distribution of incident light in the method of the present invention, Figure J, Figures 5 and 6 are diagrams showing some steps of the method of the present invention. 1... TV camera, 2... Light source, 3... Cloudy glass, 4... Half mirror 15... Observation object, 6... Filter, 7... Pseudo observation object,
8...Photograph machine, 9...Positive film. Figure 1 Figure 2 T. Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 12 (bl

Claims (1)

[Claims] 1. While projecting light from a light source onto the surface of an object to be observed, the surface of the object is imaged by a television camera or the like #jl! Viewed by vessel? In the method, a filter consisting of a negative image of the distribution of reflected light on each part of the surface of the object is interposed in the optical path between the light source and the object, and observation is performed while projecting the light that has passed through the filter onto the object. A method of observing objects characterized by: 2. In a method of observing the surface of an object to be observed using an imaging device such as a television camera while projecting light from a light source onto the surface of the object, the object is made of the same material and has at least the same size area and the same surface condition as the object. A pseudo observation object is placed in the same position as the object, and the surface of the pseudo observation object is photographed on a positive film using a camera placed in the same position as the imaging device to produce a positive original image of the pseudo observation object. (By using the image as a filter and placing the filter in the optical path between the light source and the object, the light passing through the filter can be converted into a linear motion. A method of observing objects characterized by observing objects while projecting them onto Iho.