JP2522191B2 - IC lead height measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC lead height measuring device, and more particularly to an IC lead height measuring device for measuring the height of each lead from the reference surface when the IC is placed on the reference surface. .

[0002]

2. Description of the Related Art A conventional IC lead height measuring apparatus for measuring the flatness of the leads of a semiconductor device is, for example, as shown in Japanese Patent Application No. 02-269823, a laser is applied to the leads from below the semiconductor device. The height is measured by scanning the light, detecting the position change of the reflected beam spot within the scanning line, and mechanically moving either the semiconductor element side or the height measurement optical system side. Is configured to measure height.

FIG. 6 is a perspective view showing the structure of a conventional IC lead height measuring device. The lead height measuring device shown in FIG. 6 has a glass plate 5 on which an IC 4 is mounted and which serves as a reference surface for height measurement.
A laser light source 1 that emits a laser beam, a mirror 2 that scans the laser beam in one direction, a scanned laser beam that is focused into parallel light, and an IC beam 4 that is oblique to the glass plate 5. The projection lens 3 for scanning the lead 14, the cylindrical lens 6 whose axial direction is parallel to the scanning direction of the laser light obtained by reflecting the laser light on the lead 14, and the laser light passes through the cylindrical lens 6. A cylindrical lens 7 whose axial direction is at right angles to the scanning direction of the laser beam obtained by the above, and a one-dimensional sensor 8 which receives a beam spot obtained by condensing the laser beam by the cylindrical lens 7 and detects its position. , A height measuring optical system composed of a light-shielding mask 12 which shields specularly reflected light from the surface of the glass plate 5 in front of the one-dimensional sensor 8 and a height signal is calculated from an output signal of the one-dimensional sensor 8. height Composed of the calculation circuit 13, a sub-scanning moving mechanism 10 for moving the height measuring optical system.

In the lead height measuring apparatus shown in FIG. 6, the IC 4 is placed on the glass plate 5, and the laser beam from the laser light source 1 is used for the lead 14 of the IC 4 by using the light projecting lens 3 from below the licking of the glass plate 5. Light, and lead 14 of IC4
The reflected light from the light is focused on the one-dimensional sensor 8 by the lenses 6 and 7, the position of the focused image is detected by the one-dimensional sensor 8, and the output signal from the one-dimensional sensor 8 is processed by the height calculation circuit 13. Then, the height of the lead 14 of the IC 4 is measured.

FIG. 7 is a diagram showing a method of calibrating by obtaining the height of the upper surface of the glass plate 5 which is the reference surface by the lead height measuring apparatus of FIG. The calibration in the height direction has been performed by placing the reference block 15 having a highly precise surface flatness on the glass plate 5 and measuring the height of the lower surface of the reference block 15.

[0006]

The above-mentioned conventional lead height measuring device is used for calibration in the height direction when the glass plate is replaced due to dirt or the like on the glass plate by measuring the surface flatness. It was done by placing a high-precision reference block and measuring its height, so a high-precision and expensive reference block is required, and when dust enters between the glass plate and the reference block, There was a drawback that it was calibrated to the wrong reference plane.

[0007]

An IC lead height measuring apparatus of the present invention includes a glass plate on which an IC is mounted and which serves as a reference surface for height measurement, a laser light source for emitting laser light, and the laser light. A mirror that scans radially around a single point,
A light projecting lens that condenses the scanned laser light into parallel light and scans the leads of the IC from an oblique angle with respect to the glass plate; and the laser light on the back surface of the leads or the front surface of the glass plate. A first cylindrical lens in which the scanning direction of the laser beam obtained by reflection is parallel to the axial direction, and the scanning direction of the laser beam obtained by passing the laser beam through the first cylindrical lens are orthogonal to the axial direction. A second cylindrical lens, a first one-dimensional sensor arranged at a position to receive scattered light from the lead of the IC that has passed through the second cylindrical lens, and the first one-dimensional sensor. The surface of the glass plate that has been arranged in parallel with the first one-dimensional sensor and has passed through the second cylindrical lens so that the electrical zero point is at the same position with respect to the light-condensing position measurement direction. A second one-dimensional sensor arranged at a position for receiving reflected light from the above, and a height calculation circuit for calculating the height of the lead from the output signals of the first one-dimensional sensor and the second one-dimensional sensor It is configured to include and.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the present invention. The IC lead height measuring apparatus of this embodiment has a glass plate 5 on which an IC 14 is mounted and whose upper surface serves as a reference surface for height measurement, a laser light source 1 for emitting laser light, and a laser light at a certain point. The mirror 2 that scans radially, the projection lens 3 that collects the scanned laser light into parallel light, and scans the back surface of the lead 14 of the IC 4 from an angle oblique to the glass plate 5, and the laser light leads. First cylindrical lens 6 in which the scanning direction of the laser light obtained by reflection on the back surface of 14 or the surface of glass plate 5 is parallel to the axial direction, and the laser light obtained by passing the laser light through cylindrical lens 6. Second cylindrical lens 7 whose axis is at right angles to the scanning direction and the first one-dimensional position arranged to receive scattered light from leads 14 of IC 4 that have passed through second cylindrical lens 7. Sensor 8 and the first one-dimensional sensor 8 provided in parallel with the first one-dimensional sensor 8 and the electric zero point are at the same position in the condensing position measurement direction, and are specularly reflected from the surface of the glass plate 5. A height measurement optical system including a second one-dimensional sensor 9 arranged at a position for receiving light, and a lead from the output signals of the first one-dimensional sensor 8 and the second one-dimensional sensor 9. Height calculation circuit 11 for calculating height
And a sub-scanning moving mechanism 10 for moving the height measuring optical system.

FIG. 2 is a view showing the relationship between the condensed images of the laser reflected light on the one-dimensional sensors 8 and 9. By appropriately designing the cylindrical lenses 6 and 7, the laser beam specularly reflected from the glass plate 5 at the positions of the sensors 8 and 9 is focused on the dot-shaped elephant 22 and the reflected light scattered from the lead 14 is collected. The light can be focused on an elliptical elephant 22 which is long in the direction orthogonal to the light position measurement direction. The first one-dimensional sensor 8 receives the condensed image of the reflected light from the lead 14 of the IC 4 on a part of 21 but reflects the reflected light (image 22) from the glass plate 5 which serves as a reference surface during height measurement. It is placed in a position that does not receive light. The second one-dimensional sensor 9 is arranged such that the electric zero point is the same as that of the first one-dimensional sensor 8 at the position where the reflected light from the glass plate 5 which serves as a reference surface when measuring the height is received. It That is,
When the image 21 of the reflected light from the lead 14 is at the electrical zero point on the one-dimensional sensor 8, the one-dimensional sensor 9 also receives the image 21 at the electrical zero point. By designing the combination of the cylindrical lenses 6 and 7 so that the specularly reflected light from the glass plate 5 is condensed at one point on the second one-dimensional sensor 9, the scattered light from the lead 14 of the IC 4 is condensed. The image is focused only in the position measurement direction and becomes an elliptical image long in the direction orthogonal to it.

FIG. 3 is a height signal a and a light quantity signal b based on the output signal from the first one-dimensional sensor 8, and FIG. 4 is a height signal c and a light quantity signal d based on the output signal from the second one-dimensional sensor 9. FIG. 5 shows an output signal e of the height calculation circuit 13 which is a combination of the height signals a and c from the first one-dimensional sensor 8 and the second one-dimensional sensor 9. In FIGS. 3, 4, and 5, the horizontal axis represents the position in the scanning direction of the laser light. A threshold value is set for the light amount signal b obtained from the output of the first one-dimensional sensor 8, and the height signal a is validated when the threshold value is equal to or higher than the threshold value, and the second signal is set when the threshold signal is equal to or lower than the threshold value. The height signal c obtained from the output of the one-dimensional sensor 9 is validated. Since the height signal e obtained from the height signals a and c of this effective portion includes both the information of the glass surface and the height of the lead, the height of the lead can be directly obtained from this signal e. .

[0012]

Since the lead height measuring apparatus of the present invention is configured to simultaneously measure the reference plane directly by the reflected light from the glass plate surface when measuring the lead height, it is highly accurate and expensive. There is an effect that the reference block is not required, the labor of the operator can be greatly saved, and inaccurate calibration due to floating of the reference block due to dust or the like can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view showing the configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing condensed images on the one-dimensional sensors 8 and 9 shown in FIG.

FIG. 3 is a waveform diagram showing the amount of light and the height according to the output of the one-dimensional sensor 8 shown in FIG.

FIG. 4 is a waveform diagram showing the amount of light and the height according to the output of the one-dimensional sensor 9 shown in FIG.

5 is a waveform diagram showing an output of the height calculation circuit 13 shown in FIG.

FIG. 6 is a perspective view of a conventional IC lead height measuring device.

FIG. 7 is a diagram for explaining a calibration method of the IC lead height measuring device of FIG.

[Explanation of symbols]

 1 Laser light source 2 Mirror 3 Projection lens 4 IC 5 Glass plate 6, 7 Cylindrical lens 8, 9 One-dimensional sensor 10 Sub-scanning moving mechanism 11 Height calculation circuit 12 Light-shielding mask 13 Height calculation circuit 14 Lead 15 Reference block

Claims (1)

(57) [Claims] 1. A glass plate on which an IC is mounted and which serves as a reference plane for height measurement, a laser light source for emitting laser light, a mirror for radially scanning the laser light around a certain point, and the scanning. And a projection lens that condenses the laser light into parallel light and scans the leads of the IC from an oblique angle with respect to the glass plate; and the laser light is reflected on the back surface of the leads or the front surface of the glass plate. A first cylindrical lens in which the scanning direction of the obtained laser light is parallel to the axial direction, and a second cylindrical lens in which the scanning direction of the laser light obtained by passing the laser light through the first cylindrical lens is orthogonal to the axial direction Cylindrical lens, a first one-dimensional sensor arranged at a position for receiving scattered light from the lead of the IC that has passed through the second cylindrical lens, and the first one-dimensional sensor And the reflected light from the surface of the glass plate that has been parallel to the first one-dimensional sensor and has passed through the second cylindrical lens so that the electrical zero point is at the same position with respect to the condensing position measurement direction. A second one-dimensional sensor arranged at a position for receiving light, and a height calculation circuit for calculating the height of the lead from the output signals of the first one-dimensional sensor and the second one-dimensional sensor. Characteristic I
C lead height measuring device.