JPH0756877B2 - Lead flatness measuring device for semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention draws downward from each side of a package,
The present invention relates to a lead flatness measuring device for a semiconductor device, which is used to detect the unevenness of the lower surface of a large number of leads whose tips are bent outward.

[Conventional technology]

In the surface mount type package type semiconductor device, the lower surface of the lead extending from each side is soldered to each electrode on the insulating substrate, but if the difference in the unevenness of each lower surface is large, the connection may be defective. Become. Therefore, it is necessary to measure the flatness of the lower surface of each lead.

FIG. 6 is a schematic diagram of the configuration of a conventional lead flatness measuring device for a semiconductor device. In the figure, reference numeral 1 denotes a surface-mounting type semiconductor device, in which a large number of leads 2 are extended downward from each side 1a of a resin-sealed package, and a tip portion thereof is horizontally bent outward. 3 is a mounting table on which the semiconductor device 1 is placed on the upper surface of the lower surface of each lead 2; 4 is an illuminating device for irradiating the end surface 2a of each lead 2 and the side surface 3a of the mounting table 3 with irradiation light 4a;
Are four image pickup devices that image the side 1a of the semiconductor device 1, the end face 2a of each lead 2 and the side face 3a of the mounting table, and output image information 6, and 7 is the image information connected to the corresponding image pickup device 5. 6 is input, and lead lower surface height detecting means for outputting lower surface height information 8 of each lead 2, 9 is lead flatness detecting means for inputting each lead lower surface height information 8 and detecting flatness of each lead lower surface. Is.

Next, the operation of the above conventional device will be described.

The semiconductor device 1 to be measured is placed on the upper surface of the mounting table 3 in contact with the lower surfaces of the leads 2. The illuminating light 4a of the illuminating device 4 irradiates the end surface 2a of each lead 2 and the side surface 3a of the mounting table 3, and the reflected light enters the image pickup device 5, is converted into image information 6, and is output. The lead lower surface height detecting means 7 that has received the image information 6
The gap t between the lower surface of each lead 2 and the upper surface of the mounting table 3 (7th
(See FIGS. 8A and 8B) is detected and output as the lead bottom surface height information 8. This lead bottom surface height information 8 is input to the lead flatness detecting means 9 and tabulated, and the highest lead height H is obtained.
(See FIG. 8) is detected and the lead flatness of the semiconductor device 1 is determined.

However, as shown in FIG. 7, the end surface of each lead 2 is
2a has an inclined surface in addition to the vertical surface.

In FIG. 7 (a), the end surface 2 a of the lead 2 is a vertical surface, and an appropriate reflected light 4 b due to the irradiation light 7 a from the illumination device 4 is provided.
Enters the imaging device 5. As a result, as shown in FIG. 8 (a), images of the end surface 2a of the lead 2 and the mounting table side surface 3a are taken, and the lower surface clearance t of the lead 2, that is, the lower surface height H of the lead 2 is accurately taken. , Image information 6 is output.

Next, as shown in FIG. 7 (b), when the end surface 2a of the lead 2 is inclined upward, the irradiation light 4a is reflected upward and does not enter the image pickup device 5, or a very small amount of incidence. It becomes the amount. Therefore, as shown in FIG. 8B, the end surface 2a of the lead 2 is not clearly imaged, and the gap t, that is, the height H of the lower surface of the lead 2 is not detected.

Further, as shown in FIG. 7C, if the end surface 2a of the lead 2 is inclined downward, the irradiation light 4a is totally reflected obliquely downward,
It is incident on the imaging device 5. For this reason, as shown in FIG. 8 (c), halation may occur, the clearance t, and accordingly, the lower surface height H of the lead 2 may not be detected accurately, and may be erroneously detected like the height h. There is.

[Problems to be Solved by the Invention]

The conventional lead flatness measuring device for a semiconductor device described above has a problem that the bottom surface height of the lead 2 cannot be accurately detected if the end surface 2a of the lead 2 is inclined with respect to the vertical direction.

In addition, it corresponds to each side of the semiconductor device.
4. Since the image pickup device 5 and the lead lower surface height detecting means 7 are required, there is a problem that the equipment becomes expensive.

The present invention has been made to solve such a problem, and even if the end faces of each lead are inclined with respect to the vertical direction, the height of the bottom face of the lead is detected with high accuracy, and the illuminating device and the imaging device It is an object of the present invention to obtain a lead flatness measuring device for a semiconductor device, which requires only two sets.

[Means for Solving the Problems]

The lead flatness measuring apparatus for a semiconductor device according to the present invention is provided with a transparent mounting plate on a mounting table, and the semiconductor device is mounted on the transparent mounting plate so that the leads are in contact with the lower surface of the mounting plate.
A light-shielding band pattern is formed at a predetermined distance outward from the end surface of each lead group, and the mounting table is rotated by the rotation driving means.

Also, with respect to the end portion of the lead group for one side of the semiconductor device,
A first image pickup device for picking up an image from above and a second image pickup device for picking up from an obliquely upper side are arranged, and an end portion of the lead group for one side is irradiated from below and the first image pickup device. The first illuminating device corresponding to No. 1 and the second imaging device corresponding to the second imaging device that irradiates obliquely upward from below are arranged.

Further, the image information from the second image pickup device and the first lead end distance detecting means for inputting the image information from the first image pickup device and outputting substantially horizontal distance information between the lead end and the light-shielding band pattern are displayed. Second lead end distance detecting means is provided which outputs the information on the inclination distance between the lead end and the shading band pattern which is input.

The information from the first and second lead end distance detecting means is input to the lead lower surface height detecting means and output as lead lower surface height information. This information is stored in a storage device for each lead group on each side of the semiconductor device, and this information is put into a lead flatness detector to detect the lead flatness by the height of the lower surface of the lead from the upper surface of the transparent mounting plate. It is something that is done.

[Action]

In the present invention, the mounting table is rotated by 90 °, and the lead group for each side of the semiconductor device is imaged by the first and second image pickup devices, and the first and second lead end distance detection means are used. , Information about the horizontal distance from the light-shielding band pattern at the lead end and diagonal distance information is output, and height information is output by the lead lower surface height detection means based on these information. This height information is stored in a storage device and stored for each side, and this information is stored in the lead flatness detecting means to find the maximum height and detect the flatness of the lower surface of the lead.

In this way, the flatness of each side with respect to the lower surface of the lead group is detected by the two sets of the illumination device and the imaging device.

〔Example〕

FIG. 1 is a schematic configuration diagram showing an embodiment of a lead flatness detecting device for a semiconductor device according to the present invention. In the figure,
In the surface-mounting type semiconductor device 1, a large number of leads 2 are downwardly extended from each side 1a from a resin-sealed package, and a tip portion is horizontally bent outward.

10 is a mounting table, which is rotatably supported by a supporting means (not shown). Reference numeral 11 denotes a transparent mounting plate fixed to the drawing-out portion 10a of the mounting table 10. A light shielding band pattern 11a is provided on the transparent surface of the semiconductor device 1 at a predetermined distance from the end surface 2a of the lead 2 group on each side. Is formed in. 12 is a drive motor,
The mounting table 10 is rotated by 90 ° via the belt 13. A first illuminating device 14a for irradiating the ends of the leads 2 on one side of the semiconductor device 1 on the transparent mounting plate 11 from below to above;
A second illuminating device 14b that illuminates obliquely upward and outward is provided. 15a corresponds to the upper side of the first lighting device 14a,
With the first image pickup device for picking up an image of the end of the lead 2, the image information 16
Output a. Reference numeral 15b is a second image pickup device corresponding to the diagonally upper outer side of the second lighting device 14b and picks up an image of the end portion of the lead 2 with an inclination angle, and outputs image information 16b.

Image information 16a is entered in 17a, first lead end distance detecting means for detecting a substantially horizontal distance between the lead 2 end and the light-shielding band pattern 11a, and image information 16b is entered in 17b. Second lead end distance detecting means for detecting the inclination distance from 11a, 19 is a lead to which the horizontal distance information 18a and inclination distance information 18b are input and which calculates the height of the lower surface of the lead 2 from the transparent mounting plate 11 A bottom surface height detecting means, 21 is a storage device for receiving the height information 20 from the lead bottom surface height detecting means 19 and storing the height information for each group of the leads 2 on each side in the sections 21a to 21d. Is a lead flatness detecting means which receives the height information 22 of each lead 2 group from the storage device 21, takes the maximum value due to the difference in height of the lower surface of the lead, and outputs it as the lead flatness.

FIG. 2 shows the positional relationship of the optical system with respect to the ends of the leads 2 of the semiconductor device 1 on the transparent mounting plate 11 of FIG. With respect to the upper surface of the transparent mounting plate 11, P is a vertical line, θa is an elevation angle of the central axis of the imaging device 15a, and θb is an elevation angle of the central axis of the imaging device 15b. L indicates the horizontal distance between the end of the lead 2 and the inner end of the light-shielding band pattern 11a, and H indicates the height (gap) of the lower surface of the lead 2 with respect to the upper surface of the transparent mounting plate 11. The semiconductor device 1 on the transparent mounting plate 11 of FIG. 2 is shown in plan view in FIG. The height H is 0 when the lower surface of the lead 2 is in contact with the transparent mounting plate 11.

Next, the operation will be described.

As shown in FIG. 1, the semiconductor device 1 is mounted on the transparent mounting plate 11. By the first and second illumination devices 14a and 14b, the group portion of the lead 2 on one side is arranged from the lower side to the first and second imaging devices.
Irradiate in the directions of 15a and 15b. The first imaging device 15a is
The leads 2 and the light-shielding band pattern 11a are imaged so as to be shaded from a substantially vertical direction, and the image signal 16a is output.
This image is shown in FIG.

The second image pickup device 15b picks up an image from the diagonally upper side so that each lead 2 and the light-shielding band pattern 11a are shaded, and outputs the image signal 16b. This image is shown in FIG.

The image signal 16a is input to the first lead end distance detecting means 17a, and the distance L between the end of the lead 2 and the inner end of the light-shielding band pattern 11a is L.
It detects a (see FIG. 2) and outputs the distance information 18a.
The second lead end distance detecting means 17b receives the image signal 16b, detects the inclination distance Lb (see FIG. 2) between the end of the lead 2 and the inner end of the light-shielding band pattern 11a, and outputs the distance information 18b.

Then, the lead lower surface height detecting means 19 detects the distance information 18a, 18
b is input and the set horizontal distance L and elevation angle θa, θ
From b, the height H of the lower surface of the lead 2 from the upper surface of the transparent mounting plate 11
Is calculated and detected, and the height information 20 is output.

The storage device 21 in which the height information 20 is stored is the imaging device 15
The height H of the lower surface of the lead 2 on that side of the semiconductor device 1 captured by a and 15b is stored in the section 21a.

Next, the drive motor 12 rotates the mounting table 10 90 °,
The group of leads 2 on the next side of the semiconductor device 1 has first and second groups.
When the image pickup device 15a, 15b reaches a predetermined image pickup position, it stops. By the same operation as above, the lower surface height H of the lead 2 on the next side is stored in the section 21b. Lead 2 on the other side
The same operation is repeated for the group (2), and the lower surface height H of the lead 2 is stored in the sections 21c and 21d.

Next, the lead flatness detecting means 23 receives the height information 22 of each side from the storage device 21, selects the one having the largest value and outputs it, and uses this as the lead flatness of the semiconductor device 1. To do.

Next, the detection of the height H of the lower surface of the lead 2 from the upper surface of the transparent mounting plate 11 will be described in more detail.

The image information 16a of the first image pickup device 15a is as shown in FIG. 4, and the lead end distance detecting means 17a includes the lead 2 end and the light-shielding band 1.
Detect the gap distance La of 1a. The image information 16b of the second image pickup device 15b is as shown in FIG. 5, and detects the distance Lb between the end of the lead 2 and the inclined gap between the light shielding band 11a.

In FIG. 2, the following equation is established from the positional relationship of the optical system.

La = Lsinθa + Hcosθa (1) Lb = Lsinθb + Hcosθb (2) where θa is 90 ° or less and is equal to 90 ° or close to 90 °, and L >> H, Hcosθb≈ It becomes 0. Therefore, equation (1) becomes La ≈ Lsinθa (3).

From the expressions (3) and (2), H = {Lb−La (sin θa / sin θb)} / cos θb (4)

The first image pickup device 15a is arranged at an elevation angle of about 90 ° with respect to the upper surface of the transparent mounting plate 11, and θa and θb are known, and the lead lower surface height detecting means 19 uses the lead end distance La, Lb
And θa, θb, the height H of the lower surface of the lead 2 from the upper surface of the transparent mounting plate 11 is calculated and detected.

In the above embodiment, the belt transmission means is used as the rotation transmission means from the drive motor 12 to the mounting table 10, but the rotation transmission means is not limited to this, and may be gear means, for example.

Further, in the above-mentioned embodiment, the groups of the leads 2 are respectively output from the four side edges of the semiconductor device 1, but the present invention can also be applied to the case where the lead groups are respectively output from the opposing two side edges or the three side edges. .

〔The invention's effect〕

As described above, according to the present invention, the rotating mounting table is provided with the transparent mounting plate, and the transparent mounting plate has an upper surface on which end faces of the lead groups on the respective sides of the semiconductor device to be measured to be mounted. A light-shielding band pattern is formed outwardly with respect to the above, and the first lighting device irradiates the lead end portion for one side upward from below,
The second illumination device obliquely irradiates the lead end portion for one side from the lower side to the upper outer side, and the first image pickup device picks up the image of the lead end portion from substantially vertically above and outputs the image information. The device is configured to image the lead end from the diagonally upper outer side to output image information. The information from the first image pickup device is put into the first lead end distance detecting means to detect a substantially horizontal distance between the lead end and the light-shielding band, and the information from the second image pickup device is detected to the second lead end distance. Device, the inclination distance between the lead end and the light-shielding band is detected, the horizontal distance information and the inclination distance information of the lead end are placed in the height detecting means, and the height of the lower surface of the lead from the upper surface of the transparent mounting plate is calculated. It detects it. Since this height information is put in the image device and the height of each lead lower surface is stored, these height information is put in the lead flatness detecting means, and the flatness is detected from all the lead lower surface heights. Highly accurate flatness is surely obtained.

Further, the illumination device, the image pickup device, and the lead end distance detection means may be provided for two sets, and the height of the lead group on each side is detected by rotating the mounting table, which is less expensive than the conventional device.

[Brief description of drawings]

FIG. 1 is a schematic diagram of the configuration of a lead flatness measuring apparatus for a semiconductor device according to an embodiment of the present invention, FIG. 2 is a layout diagram of an optical system with respect to the lead end portion of FIG. 1, and FIG. 4 is a partial plan view of the lead end and the transparent mounting plate, FIG. 4 is a partial plan view showing an image of the lead end by the first image pickup device of FIG. 2, and FIG. 5 is a second plan of FIG. FIG. 6 is a partial plan view showing an image of a lead end portion by an imaging device, FIG. 6 is a schematic configuration diagram of a conventional lead flatness measuring device of a semiconductor device, FIG. 7 (a),
6 (b) and 6 (c) are side views showing the relationship between the irradiation light and the reflected light when the lead end surface of FIG. 6 is vertical, tilted upward and tilted downward, and FIGS. 8 (a), 8 (b) and 8 (c). 7A and 7B are partial front views showing image information in the cases of FIGS. 7A, 7B and 7C, respectively. 1 ... Semiconductor device, 2 ... Lead, 2a ... End face, 10 ...
Mounting table, 10a …… Drawing section, 11 …… Transparent mounting plate, 11a ……
Shading band pattern, 12 …… Drive motor, 13 …… Belt, 14
a ...... first lighting device, 14b ... second lighting device, 15a ...
... first imaging device, 15b ... second imaging device, 16a, 16b ...
... Image information, 17a ... First lead end distance detecting means, 17b
...... Second lead end distance detecting means, 18a, 18b ...... Distance information, 19 ...... Lead bottom surface height detecting means, 20 ...... Height information,
21 ... Storage device, 22 ... Height information, 23 ... Lead flatness detecting means In the drawings, the same reference numerals indicate the same or corresponding portions.

Claims (1)

[Claims] 1. A device for detecting flatness based on a difference in height of leads undersides of respective sides of a surface-mount type semiconductor device, wherein a central portion is hollowed out and is rotated to a required rotation angle position by a rotation driving means. The rotary mounting table, which is fixed to the drawing-out part of the mounting table, has a light-shielding band pattern formed on the upper surface thereof with a predetermined distance outward from the end of the lead group on each side of the semiconductor device to be mounted. A transparent mounting plate, a first image pickup device for imaging the lead group and the light-shielding band pattern portion for the one side from above at a large elevation angle with respect to the top surface of the transparent mounting plate, and a small elevation angle. A second illuminating device that obliquely images from above, a first illuminating device that faces the first imaging device from below and irradiates the lead group from below, and a lead that obliquely faces the second imaging device from below. Irradiate the group from diagonally below Illumination device, first lead end distance detecting means for detecting substantially horizontal distance between the lead end and the light-shielding band pattern, and image information from the second image pickup device. Information is input, distance information is input from second lead end distance detecting means for detecting the inclination distance between the lead end and the light-shielding band pattern, and distance information is input from each of the first and second lead end distance detecting means, and the transparent mounting is performed. The lead lower surface height detecting means for calculating and detecting the height of the lower end surface of the lead from the upper surface of the mounting plate, the height information from the lead lower surface height detecting means is inputted, and the height for each lead group on each side is stored. 1. A lead flatness measuring device for a semiconductor device, comprising: a storage device to be stored; and lead flatness detecting means for inputting height information from the storage device and outputting it as a lead underside flatness according to the maximum height.