JPH06147858A - Displacement measuring equipment - Google Patents

Abstract

PURPOSE:To obtain stabilized measurements while placing the lead of an IC chip on the top surface of a reference table. CONSTITUTION:A mirror face for reflecting a predetermined quantity (sensible quantity of an optical position detecting element 17) or more of incident laser light LB in normal direction N is formed on the top surface 11a of a reference table 11 for mounting the lead L of an IC chip.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a displacement measuring device used for detecting warp or bending of leads of an IC chip.

[0002]

2. Description of the Related Art In a conventional displacement measuring apparatus, an IC chip is arranged so as to be horizontal with respect to a reference plane, and a plurality of leads (measurement objects) extending from the IC chip are vertically attached to the upper surface of the reference plane. A laser beam is emitted from a light projecting means installed in any direction to reflect (diffuse reflection). Then, a part of the reflected light (however, a certain amount of light or more) is received by the light receiving means installed in a predetermined direction other than the vertical direction, and the position of the light receiving point (spot) in the light receiving means is changed. Is detected, and the vertical displacement of the upper surface of the lead with respect to the reference plane is measured. By using such a displacement measuring device, the height of the upper surface of each lead and its horizontal position can be detected, and the warp or bend of each lead can be inspected.

Here, for example, if the above-mentioned reference surface is formed on the upper surface of the table and the IC chip (or lead) is placed on the upper surface of the reference table, the IC chip can be held in the vertical direction, and the measurement work can be performed. The top is convenient. However, it is often the case that a part of the laser light diffusedly reflected on the upper surface of the reference stage through the leads hits the side surface of each lead and is reflected again and then received by the light receiving means. In such cases,
There is a problem that the position of the spot in the light receiving means cannot be clearly detected and the stability of measurement is impaired.

For this reason, the conventionally used displacement measuring device supports the IC chip in a state of floating in the air so as to be horizontal to the reference plane. According to this, the laser light radiated to the upper surface of each lead is reflected there and is received by the light receiving means, but the laser light radiated between the leads passes therethrough and proceeds as it is, and the light receiving unit Will not be received by. Therefore, stable measurement results can be obtained.

[0005]

However, in such a displacement measuring device, it is difficult to support the IC chip in the air so as to be horizontal to the reference plane. Also, for such aerial support, I
There is also a problem that it is troublesome because it is necessary to prepare a special supporting means adapted to the C chip.

The present invention has been made in view of the above problems, and a displacement measuring apparatus capable of obtaining a stable measurement result with an IC chip (or lead) placed on the upper surface of a reference table. Is intended to provide.

[0007]

In order to achieve the above object, in the first displacement measuring apparatus of the present invention, the upper surface of the reference table has a predetermined amount of laser light or more of the laser light irradiated thereon. To form a mirror surface that reflects in the vertical direction. Further, in the second displacement measuring apparatus of the present invention, the antireflection portion is formed on the upper surface of the reference table so as not to reflect the laser light of a predetermined light amount or more among the laser light irradiated onto the reference base.

[0008]

In the first displacement measuring device, most of the laser light reflected on the upper surface of the reference table passes between the leads and returns in the vertical direction (that is, the light projecting direction). The amount of light is less than the predetermined amount and is not the object of measurement. Therefore, by using this displacement measuring device, stable measurement results can be obtained as if the leads (IC chips) were supported in the air. Also,
In the second displacement measuring device, most of the laser light emitted to the upper surface of the reference table through the leads is not absorbed and reflected, so that the light receiving means does not receive a predetermined amount of light, and the measurement target do not become. Therefore, a stable measurement result can be obtained even by using this displacement measuring device.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 shows the configuration of a first displacement measuring apparatus according to the present invention. The displacement measuring device 10 includes a reference table 11 and a measuring unit 1 arranged above the reference table 11.
2 and a display unit 13. As shown in FIG. 2, a plurality of leads L, L, ... Extending from the IC chip C are mounted on the upper surface (reference surface) 11a of the reference table 11. Thereby, the chip C can be held in the vertical direction and the horizontal direction without using any special holding means. The measuring unit 12 is directed toward the upper surface 11a of the reference table 11 while converging the semiconductor laser 14 driven by the driver 14d and the laser light LB emitted from the semiconductor laser 14, and is perpendicular to the upper surface 11a. And a condenser lens 15 for performing spot irradiation from the direction N.

Further, the measuring section 12 has an imaging lens 16 mounted adjacent to the condenser lens 15 in a detection direction (predetermined direction) M having a predetermined angle of attack with respect to the vertical direction N, An optical position detection element 17 arranged so as to be orthogonal to the detection direction M and a calculation processor 18 are provided farther than the imaging lens 16 in the detection direction M. The imaging lens 16 condenses the laser light LB which is irradiated on the upper surface of the lead L and diffused and reflected in various directions, and proceeds toward the detection direction M, and forms a spot on the surface of the light position detection element 17. Make them image. The light position detection element 17 has a detection direction M.
The position of the spot on the surface of the element 17 is detected with reference to the intersection point with and, and a detection signal is output. The arithmetic processor 18 determines the upper surface 11 of the reference table 11 based on this detection signal.
The height of the upper surface of the lead L with respect to a is measured, and the display device 1
Display in 3.

The measuring unit 12 thus constructed is shown in FIG.
As indicated by the arrow, the displacement in the height direction of the reflection position of the laser light LB with respect to the upper surface 11a of the reference table 11 within the range of movement is measured by moving it in parallel (horizontally) to the upper surface 11a of the reference table 11. be able to. Therefore, for example, when the lead L is in close contact with the upper surface 11a of the reference base 11 as shown by the solid line in FIG.
The position of the spot on the surface of the light position detecting element 17 is x
It is 1. The arithmetic processor 18 displays the height H1 of the upper surface of the lead L on the display device 13 based on the position x1 of the spot. Further, when the lead L is lifted from the upper surface 11a of the reference table 11 as shown by the chain line, the position of the spot on the surface of the optical position detecting element 17 is x2. The arithmetic processor 18 displays the height H2 of the upper surface of the lead L on the display device 13 based on the position x2 of this spot. In this way, the height of the upper surface of each lead L and the horizontal interval at which the height is displayed are measured and compared with the original height H1 and the interval I1 to bend the warped lead L'and bend in the horizontal direction. It is possible to inspect for the presence of the lead L ″.

However, the laser light LB diffusedly reflected on the upper surface 11a of the reference table 11 may hit the side surface of the lead L and be reflected in the detection direction M, and the reliability of the measurement result can be obtained by detecting this laser light. -Stability may be impaired. By the way, in order to be able to measure the displacement in the device 10, as shown in FIG. 3A, the laser beam L diffusely reflected on the upper surface of the lead L and travels in various directions.
Of B, the light amount of the laser light that advances toward the detection direction M and is focused on the light position detection element 17 needs to be equal to or more than the sensitivity light amount (predetermined light amount) of the light position detection element 17 (each). The length of the arrow indicates the amount of laser light.) Therefore, in the present device 10, the mirror surface 11k is formed on the upper surface 11a of the reference table 11.

Laser light LB irradiated on the mirror surface 11k
Is mostly in the vertical direction N, as shown in FIG.
Reflect on. Then, the remaining laser light diffusely reflects and travels in a direction other than the vertical direction N, but the light amount thereof does not reach the sensitivity light amount. Therefore, even if the laser beam LB reflected on the mirror surface 11k is reflected on the side surface of the lead L and hits the surface of the optical position detecting element 17, the laser beam LB is not detected by the optical position detecting element 17. Therefore, by using the present apparatus 10, it is possible to obtain stable measurement results as if the leads L were supported in the air and the laser light LB irradiated between the leads passes through without being reflected. . Moreover, as described above, since the chip C can be horizontally supported without using any special supporting means,
It is convenient for measurement work.

(Second Embodiment) Next, a second displacement measuring device according to the present invention will be described. Since this displacement measuring apparatus is almost the same as the first apparatus 10, the reference table different from the first apparatus 10 will be described here with reference to FIG. The upper surface 1 of this reference stand 11 '
1a 'has a groove (antireflection portion) 11 extending in the horizontal direction.
m'is formed. The bottom surface and wall surface of the groove 11m 'are painted black.

In the displacement measuring device 20 constructed as described above, as shown in FIG.
The lead L is placed on the a'in such a manner as to extend over the groove 11m '. Then, in the detection direction M of the laser light LB that is irradiated onto the upper surface of the lead L and diffusely reflected here.
The light traveling toward (1) is detected by the optical position detecting element (17: see FIG. 1).

On the other hand, the laser beam LB irradiated between the leads L, L passes through the space between them and is received in the groove 11m ',
Diffuse reflection occurs on the bottom surface. As described above, the groove 1
Since the bottom surface of 1 m'is black, a part of the irradiated laser light LB is absorbed as heat by the bottom surface of the groove 11 m ', and the amount of the laser light after reflection is reduced accordingly. Further, the reflected laser light LB is reflected again on the wall surface of the groove 11m '. Also at this time, since the wall surface of the groove 11m 'is black, a part of the laser beam LB after being re-reflected is absorbed by the wall surface of the groove 11m' as heat, and the light amount of the re-reflected laser beam LB is reduced accordingly. . In this way, the amount of the laser beam LB becomes minute while being reflected one after another in the groove 11m ′,
When the light is emitted to the outside of 1 m ', the light amount is far below the sensitivity light amount of the light position detecting element. Therefore, even if it hits the surface of the optical position detecting element, it is not detected by the optical position detecting element, and the lead L is supported in the air, and the laser beam LB irradiated between the leads passes as it is. As a result, stable measurement results can be obtained. The tip C can be supported horizontally without using any special supporting means, which is also the same as the first measuring apparatus 10 described above.

[0017]

As described above, in the displacement measuring apparatus of the present invention, the measuring object is placed on the upper surface of the reference table so that the measuring object is held in the vertical direction. . Therefore, using this displacement measuring device,
It is possible to easily perform the measurement work without using a special means for holding the measurement object. Further, in this displacement measuring device, by forming a mirror surface or forming a recess on the upper surface of the reference table, the laser light directly irradiated on the upper surface of the reference table exceeds a predetermined light amount in a predetermined direction. The light is reflected or emitted with an amount of light that does not exist. Therefore, by using this displacement measuring device, it is possible to treat the laser light radiated on the object other than the upper surface of the object to be measured in the same manner as if it passes through and is not reflected, and the object to be measured is supported in the air. As if
It is possible to obtain stable measurement results.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first displacement measuring device of the present invention.

FIG. 2 is a measurement work diagram (plan view) using the displacement measuring device.

3A and 3B are conceptual diagrams showing the progress of laser light in the displacement measuring apparatus.

4A and 4B are conceptual diagrams showing the progress of laser light in the second displacement measuring apparatus of the present invention.

[Explanation of symbols]

 10 Displacement Measuring Device 11, 11 'Reference Base 11a, 11a' (Upper Reference Base) 11k Mirror Surface 11m 'Groove (Anti-Reflection Part) 14 Semiconductor Laser 17 Optical Position Detector LB Laser Light C IC Chip L Lead (Measurement Target) ) M detection direction (predetermined direction)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumio Narui 6-17-7 Nagayama, Tama City, Tokyo Inside Texel Co., Ltd.

Claims (2)

[Claims] 1. A laser beam irradiated toward a top surface of a reference table from a direction perpendicular to the top surface of the reference table,
By receiving at least a predetermined amount of laser light reflected in a predetermined direction other than the vertical direction on the upper surface of the measurement object placed on the upper surface of the reference table, the reference table on the upper surface of the measurement object In a displacement measuring device for measuring a vertical displacement with respect to an upper surface, a mirror surface is formed on the upper surface of the reference table to reflect in the vertical direction at least a predetermined amount of laser light among the laser light irradiated on the reference base. Displacement measuring device. 2. Of the laser light emitted toward the upper surface of the reference table from a direction perpendicular to the upper surface of the reference table,
By receiving at least a predetermined amount of laser light reflected in a predetermined direction other than the vertical direction on the upper surface of the measurement object placed on the upper surface of the reference table, the reference table on the upper surface of the measurement object In a displacement measuring device for measuring a vertical displacement with respect to an upper surface, an antireflection portion is formed on the upper surface of the reference table, which does not reflect laser light of a predetermined light amount or more among the laser light irradiated onto the reference base. Displacement measuring device.