JPH02150705A - Linear object inspecting device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a device that accurately inspects the three-dimensional height shape of a linear object to be inspected, and evaluates the focal point when moving an imaging device and determines the height. The purpose of the present invention is to provide an inspection device for linear objects that can inspect the shape, and includes a pattern illumination device that indicates the measurement location of the object to be inspected;
An imaging device having means capable of imaging reflected light from the object to be inspected and moving in the vertical direction; a focus evaluation circuit that evaluates the imaging focus of the object to be inspected from an imaging signal of the imaging device; and the focus evaluation circuit. and a height detection circuit that detects the height shape of the object to be inspected from the output and the output of the imaging device vertical movement means.

[Industrial Field of Application] The present invention relates to an apparatus for accurately inspecting the three-dimensional height shape of a linear object to be inspected.

Conventionally, objects have been inspected using optical cutting methods, but inaccurate values can only be obtained depending on the inclination angle of the object.Therefore, there has been a need to develop a technique to inspect the height and shape of linear objects.

[Prior Art] Conventionally, when measuring the three-dimensional shape of an object to be inspected, particularly its height from a reference plane, an optical cutting method shown in FIG. 5 has been used.

In FIG. 5, 1 is a light source, 2 is a cylindrical lens, 3 is a reference plane, 4 is an object to be inspected, and 5 is an imaging device such as a TV camera. The light irradiated from the light source l to the object to be inspected 4 becomes a line due to the cylindrical lens 2, and the object 4
Because the height of the area hit is h, the irradiation position is shifted.

Therefore, within the field of view 6 of the TV camera 5, the image 7 on the plane and the image 8 of the object 4 are shifted by d. Therefore, when the angle that the irradiation light that has passed through the cylindrical lens 2 makes with the plane 3 is θ, the height h of the object 4 from the reference plane 3 is given by h = d tan θ.

Such inspection, three-dimensional shape inspection, is required for wire appearance inspection in the semiconductor manufacturing process. 6th
As shown in the figure, a wire 11 connects the pad electrode 12 on the semiconductor IC chip 14 and the lead frame 13 of the package.
When connecting, it is processed by automatic machine tools, but
After the wire 11 has been processed, the appearance of the wire 11 must be inspected before proceeding to the next step. When looking at one wire 11 shown in the side view of FIG.
This is because it needs to rise from the pad 12 of the IC chip 14, then descend, and be connected to the surface of the lead frame 13 in an appropriate loop shape.

If the wire 11 is hanging down as shown in FIG. 8A, if there is a conductor such as a ground conductor below the wire that has a different electrical potential than the wire, there is a risk of contact. In addition, Fig. 8B shows an abnormally high loop shape, but the mold resin injected for insulation sealing in the next step hits the wire and sweeps it away. Fig. 8C shows an abnormally high loop shape. Since there is no margin in the loop shape, there is a risk that the wire will break due to even the slightest vibration during transportation to the next process.

[Problems to be Solved by the Invention] When wire appearance is inspected using the optical cutting method, the signal strength of the captured image changes due to the inclination of the linear object, so there is a drawback that stable inspection cannot be performed. Ta.

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks and provide a linear object inspection device that can inspect the height shape by evaluating the focus when moving the imaging device.

[Means for Solving the Problems] FIG. 1 is a diagram showing the basic configuration of the present invention. In FIG. 1, 5 is an imaging device, 10 is a pattern illumination device, 11 is an object to be inspected such as a wire of an IC chip, 15 is a means for vertically moving the imaging device, 16 is a focus evaluation circuit, and 17 is a height detection circuit. shows.

In order to solve the above-mentioned problems, the present invention has the following configuration. That is, a pattern illumination device 10 that indicates the measurement location of the object to be inspected 11, an imaging device 5 having a means 15 that images the reflected light from the object to be inspected and can move in the vertical direction;
A focus evaluation circuit 16 evaluates the imaging focus of the object to be inspected 11 from the imaging signal of the imaging bag W5, and from the output of the focus evaluation circuit 16 and the output of the imaging device vertical movement means 15, the height shape of the object to be inspected is determined. and a height detection circuit 17 for detecting the height.

[Operation] The pattern illumination device 10 is capable of emitting, for example, multi-slit light in order to indicate the measurement location of the object 11 to be inspected. When a predetermined position of the object to be inspected 11 is illuminated by the pattern illumination device 10, the reflected light is imaged by the imaging device 5, and the focus evaluation circuit 16 evaluates the focus. In this method, the imaging device 5 is moved up and down using the bright spot imaged when the illumination pattern hits the object 11 as a mark, and the position where the focus is best matched is calculated. The height detection circuit 17 is informed of the movement position of the vertical movement device 15 at that time.
At other positions, focus evaluation is performed in the same way, and the movement position is communicated. The amount of movement of the vertical movement device when images of specific positions are sequentially captured by the illumination device 10 indicates the height shape (height from the reference plane) of the object to be inspected.

[Embodiment] FIG. 2 is a configuration diagram showing an embodiment of the present invention in which a multi-slit light projection device is used as a pattern illumination device and a wire is inspected as an object to be inspected. In FIG. 2, numeral 10 is a multi-slit light projection device, as shown in, for example, Japanese Patent Application No. 63-234162.

The wire 11 is irradiated with slit light. The imaging lens 18 is for a TV camera, and is located at imaging positions 5-a, 5-b,
5-c shows that when the point on the wire 11 is irradiated with the slit light, the position is changed to capture an image.

The bright spot image is imaged by the imaging device 5 via the imaging lens 18. When the imaging device is at imaging position 5-a, the signal of the bright spot is 8-a, and when it is at imaging position 5-b, it is 8-b.

If 5-c is set to 8-c, it is determined that the imaging position 5-b is closer to the focal point than the others based on the magnitude of the bright spot signal. Next 5-b
In the vicinity of , the tendency of increase and decrease of the bright spot signal is determined by slightly shifting the position. The point where the signal becomes smaller before and after that point is determined to be the focal point, and the coordinates of the imaging position are notified to a height detection circuit (not shown).

Next, bright spot images from other slits are captured in the same way,
Find the focal point. By repeating the notification of the position coordinates to the height detection circuit, a change in the bright spot image is obtained as shown in the image of the wire in FIG. Therefore, the data of the height detection circuit corresponding to this change indicates the height of the wire.

FIG. 3 is a diagram showing the surroundings of a light projector and wires when a grid light projector is used as the lighting device 10, and FIG. FIG. 3 is a diagram showing the vicinity of an optical device and wires. In each figure, the fact that light shines directly on the wire and becomes a bright spot is the same as in the case of FIG. 2, and the focus of the image from the imaging device is evaluated in the same way as in FIG. Therefore, the data notified to the height detection circuit is also the same.

[Effects of the Invention] In this manner, according to the present invention, the height of the shape that becomes the image of the bright spot position can be accurately detected. Moreover, since the inspection can be automated, even linear objects produced in large quantities can be effectively inspected.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the principle configuration of the present invention, Fig. 2 is a block diagram when a multi-slit light projector is used as an illumination device as an embodiment of the present invention, and Figs. 3 and 4 are illustrations of the illumination device. Fig. 5 is a diagram showing a linear object inspection device using a conventional light cutting method; Figs. 6 to 8 are FIG. 3 is an explanatory diagram of the wires of the IC chip. 1.10.--Illumination device 4.11.--Object to be inspected 5.--Imaging device 15.--Vertical movement means 16 for the imaging device.--Focus evaluation circuit 17.--Height detection circuit, /\, 8-a Wire entry point a arm 1 Figure 2 Wire ΦA diagram Figure 3 Four wire diagrams Figure 4

Claims (1)

[Scope of Claims] A pattern illumination device (10) that indicates a measurement location on an object to be inspected (11), and a means (15) that images reflected light from the object to be inspected (11) and can move in the vertical direction. ) an imaging device (5) having
a focus evaluation circuit (16) that evaluates the imaging focus of the object to be inspected (11) from the imaging signal of the imaging device (5), an output of the focus evaluation circuit (16), and a means for vertically moving the imaging device (1).
5) A linear object inspection device comprising a height detection circuit (17) that detects the height shape of the object to be inspected from the output.