JPH05145299A - Measuring method for narrow pitch lead of electronic component - Google Patents

Abstract

PURPOSE:To provide means for accurately measuring a lead by positioning the lead at a thinnest part of a laser spot light. CONSTITUTION:The number of leads L is counted from a reflected light incident to a photodetector 5 of a laser 3. A count of leads is compared with the number previously registered in a computer to judge propriety of height of the lead L. A distance between the laser 3 and the lead L is regulated based on the judged result, and the lower surface of the lead L is irradiated with the thinnest part 4a of a laser spot light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring leads of an electronic component, and more specifically, for irradiating the finest part of a laser spot light onto the leads to measure the floating or displacement of narrow pitch leads. Regarding means.

[0002]

2. Description of the Related Art A TAB device formed by a film carrier is known as an electronic component for achieving high density and high integration of a substrate. This TAB device has a very large number of leads extending outward from the chip, and the leads have an extremely narrow pitch. Therefore, when this is mounted on a substrate, the leads cannot be matched with the electrodes of the substrate unless the height and position of the leads are accurately measured, and bonding failure occurs. Such a problem also applies to an electronic component having a narrow pitch lead such as QFP. For this reason, laser means capable of precise measurement is used as the measuring means for the narrow pitch lead.

FIG. 1 is a side view of a lead of a TAB device during measurement. 1 is a transfer head to which the nozzle 2 is attached,
P is a TAB device adsorbed on the nozzle 2,
A large number of leads L extend outward from the chip C that is the main body. A laser device 3 has a light emitting portion 5 for the laser light 4 and a light receiving portion 6 for receiving the reflected light of the laser light 4. The transfer head 1 is moved in the XY directions to position the transfer head 1 above the laser device 3, and the light emitting unit 5 is provided on the lower surface of the lead L of the TAB device P attracted by the nozzle 2 of the transfer head 1. Laser beam 4 from
By receiving the reflected light in the light receiving unit 6, the floating and the position of the lead L are measured. In this case, in order to accurately measure the lead L, the finest portion 4a of the luminous flux of the laser light 4 must be applied to the lower surface of the lead L that is the measurement target.

[0004]

By the way, the irradiation position of the finest portion 4a on the lower surface of the lead L is set by the nozzle 2
The height h of the lower surface of the lead L (hereinafter referred to as the reference height) is calculated in advance from the thickness d of the chip C adsorbed on the substrate, the thickness m of the lead L, and the height of the lower end of the nozzle 2. Has been done. However, due to an error in assembling the nozzle 2 and an error in the thickness of the chip C, the lead L is displaced from the reference height h by a considerable height Δh, as shown by the chain line in the partially enlarged view of FIG. There are cases. In this case, lead L
Is located at a position where the light flux of the laser light 4 is much more diffused than the finest portion 4a, so that the two leads L are simultaneously irradiated with the laser light 4 and the reflected light is incident on the light receiving portion 6, as shown in FIG. Since the two leads L are measured, the positions of the individual leads L cannot be measured.

Therefore, according to the present invention, even if the height of the lower surface of the lead varies due to an error in assembling the nozzle, etc., the finest part of the laser beam is applied to the lower surface of each lead, and the leads are precisely measured. An object of the present invention is to provide a method for measuring a narrow pitch lead of an electronic component that can be used.

[0006]

To this end, according to the present invention, the number of the leads is counted from the reflected light reflected by the leads and incident on the light receiving portion, and the counted number is registered in advance in a computer. By comparing the number of leads, it is determined whether the height of the lead is appropriate, and based on the result of the determination, the distance between the laser device and the lead is adjusted so that the finest part of the laser spot light is applied to the lower surface of the lead. It was done.

[0007]

According to the above construction, when the lead is not located at the finest part of the light beam of the laser spot light but is at the position where the light beam is diffused, the two leads are mistaken for one lead as described above. Therefore, the number does not match the number registered in advance in the computer. Therefore, it is found that the lower surface of the lead is considerably displaced from the finest part of the laser beam. Therefore, the lead is measured after adjusting the distance between the laser device and the lead so that the finest part hits the lower surface of the lead.

[0008]

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

In measuring the lead of an electronic component having a narrow pitch lead such as a TAB device,
As shown in FIG. 1, the transfer head 1 is moved in the XY directions to position the transfer head 1 above the laser device 3.
Then, as shown in the directions of arrows N1 to N4 in FIG. 2, the laser beams 4 are scanned and irradiated onto the lead rows A to D of the leads L extending outward from the respective sides of the chip C, and the respective lead rows are irradiated. The heights of the leads L of A to D are measured, and the average values ha to hd of the heights of the leads of the respective lead rows A to D are obtained. HO is a reference level. FIG. 3 shows the result. As shown in FIG. 3, each lead row A to D has the finest portion 4 of the laser beam 4 due to an error in forming and assembling the nozzle 3.
It deviates from the reference height h of a and is inclined. The average values ha to hd may be obtained from the average value of the heights of the leads, or the height of the lead L at the center of each of the lead rows A to D may be the average value, and the method of obtaining the values may be arbitrary. ..

Next, the difference between the reference height h and the average values ha to hd obtained as described above, Δha = h-ha to Δhd =
Find h-hd. This difference Δha to Δhd is the allowable error T
If it is larger than the above, the two leads L are erroneously recognized as one lead L and measurement is performed, as described with reference to the partially enlarged view of FIG. If the difference Δha to hd is larger than the allowable error T, the nozzle 2 is moved up and down to adjust the distance between the lead L and the laser device 3 so that the difference is within the allowable error T. Of course, the distance may be adjusted by moving the laser device 3 up and down. hH is the upper limit height and hL is the lower limit height. By doing so, the lead L is accurately positioned on the smallest portion 4a of the laser spot light 4, and the smallest portion 4a is formed on the lower surface of the lead L.
And the position of the lead L can be accurately measured. Next, an example of a more specific measuring method will be described with reference to the flowchart of FIG.

First, as shown in FIG. 1, the device P is positioned above the laser device 3, the center of the lower surface of the chip C is irradiated with laser light, and the height H thereof is measured to obtain the thickness of the chip C. The error is calculated (steps 1 and 2). The thickness error of the chip C can be easily obtained by obtaining the height H of the lower surface from the reference level HO. Next, the nozzle 2 is moved up and down to correct this thickness error (step 3). By performing the above operation, the height error of the lead L due to the thickness error of the chip C is corrected in advance.

Next, the device P is moved to the measurement start position S1 (see FIG. 2) (step 4), and the lead row A is scanned and irradiated with the laser beam 4 (step 5). Then, the data due to noise is cut (step 6), and the missing portion of the lead coordinate data is detected (step 7). Next, the average value ha of the heights of the leads L of the lead row A is obtained from the remaining data (step 8), and then this average value ha is stored in the memory of the computer as the deviation amount Δha with respect to the reference height h ( Step 9). Then, it is confirmed whether or not the data of all the leads L is obtained, and if the number of leads L matches the number of leads L stored in advance in the computer,
It is assumed that all the leads L of the lead row A are within the tolerance T shown in FIG. 3 and that the bottom surface of all the leads L can be irradiated with the smallest detail 4a (strictly speaking, the smallest detail) of the laser spot light. Judgment is made to move to the measurement start position S2 of the next lead row B, and this lead row B is also subjected to steps 1 to 9
Is repeated (step 10).

When the number of leads L is smaller than the number registered in the computer, as shown by the chain line in the partially enlarged view of FIG. It is determined that L is erroneously recognized as one lead L, and the device P is moved by moving the nozzle 2 up and down based on the difference Δha obtained as described above.
Height correction, that is, after adjusting the distance between the lead L and the laser device 3 (step 11), the process returns to step 4 and the above steps are repeated. By doing so, the lead L can be irradiated with the finest portion 4a of the laser light 4, and the positional deviation and floating of the lead L can be accurately measured.

[0014]

As described above, according to the present invention, by counting the number of leads from the reflected light incident on the light receiving portion, and comparing the counted number with the number registered in advance in the computer, The suitability of the height of
Based on the result of the determination, the distance between the laser device and the lead is adjusted to irradiate the finest part of the laser spot light to the lower surface of the lead.
It is possible to accurately measure the lead position and the float by arranging a narrow-pitch lead such as in the finest part of the laser spot light.

[Brief description of drawings]

FIG. 1 is a front view during measurement according to the present invention.

FIG. 2 is a plan view of a TAB device during measurement according to the present invention.

FIG. 3 is a measurement diagram according to the present invention.

FIG. 4 is a flowchart according to the present invention.

[Explanation of symbols]

 2 Nozzle 3 Laser device 4 Laser spot light 4a Finest part 5 Light emitting part 6 Light receiving part P Electronic component L Lead

Claims (1)

[Claims] 1. A lead is obtained by irradiating the underside of a lead of an electronic component adsorbed by a nozzle with the smallest detail of a laser spot light emitted from a light emitting portion of a laser device and receiving the reflected light in a light receiving portion. When measuring, the number of the leads is counted from the reflected light incident on the light receiving unit, and by comparing the counted number with the number registered in advance in the computer, it is possible to determine whether the height of the leads is appropriate or not. It is characterized in that the distance between the laser device and the lead is adjusted based on the result of the determination, and then the finest part of the laser spot light is irradiated on the lower surface of the lead to measure the lead. Measuring method of narrow pitch lead of electronic parts.