JPH05157702A - Method and device for inspecting soldering lead - Google Patents

Abstract

PURPOSE:To enable a time required for monitoring and inspection to be reduced in a soldering lead inspection method. CONSTITUTION:A slit beam 20 is shed to a substrate 4 skewly in a direction matching a longer direction of a lead 3 whose width direction is soldered and while one upper part in the width direction projects from a tip 3b of the lead. Presence or absence of lead lifting is inspected based on a spacing b0 between a reflection slit beam 24b which is reflected on an upper surface 3a of the lead and a reflection slit beam 24a which is reflected on an upper surface of the substrate. Presence or absence of a fillet is inspected based on presence or absence of a reflection beam 23 which is reflected by the fillet 5 and is directed upward vertically for an upper surface of the substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soldering lead inspection method and device, and more particularly to a method and device for optically inspecting a soldering state of leads of a surface mount type semiconductor component.

The inspection of the soldering state of the leads must be carried out for two items, that is, the floating of the leads and the presence / absence of fillets.

It is also desirable that this inspection be performed as efficiently as possible.

[0004]

2. Description of the Related Art First, a soldering state of leads will be described for convenience of description.

In FIG. 7A, reference numeral 1 denotes a surface mount semiconductor component (QFP), which has a structure in which leads 3 are projected from a side surface of a main body 2.

As shown in FIG. 8, the semiconductor component 1 is surface-mounted on the surface of the substrate 4 by soldering the leads 3 onto pads (not shown) on the substrate 4.

Reference numeral 5 is a solder fillet.

Next, a conventional example will be described.

Conventionally, the inspection is performed by two steps.

FIG. 7A shows the state of the lead floating inspection process.

This inspection is performed by using the light cutting method. That is, the sheet-shaped slit light 10 is obliquely irradiated so that the width direction thereof crosses the leads 3 and the upper surface 3 a of the leads 3 is irradiated.
And the reflected slit light 11 that is specularly reflected by the upper surface 4a of the substrate 4.
The distance a of _-1 , 11 _-2 is obtained, and when the distance a is larger than a predetermined size, it is determined that there is lead floating.

FIG. 7B shows the state of the fillet inspection process.

In this inspection, the slit light 10 is turned off,
This is performed by newly irradiating parallel light 12 having a circular section to the side of the lead 3 and detecting the reflected light 13 reflected by the fillet 5 and heading directly upward. If the reflected light 13 is detected, it is determined that the fillet 5 exists, and if the reflected light 13 is not detected, it is determined that the fillet 5 does not exist.

[0014]

In the conventional inspection method, first, slit light 10 is irradiated to perform lead floating inspection, then slit light 10 is turned off, and parallel light 12 is newly irradiated to perform fillet inspection. In other words, the lead floating inspection and the fillet inspection are sequentially performed at intervals, and the inspection takes time.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a soldering lead inspection method and device that solve the above problems.

[0016]

The invention according to claim 1 is based on FIG.
In the method of optically inspecting the soldering state of the leads of the semiconductor component whose leads are soldered and surface-mounted on the upper surface of the substrate by the fillet as shown in FIG. The slit for irradiating the substrate 4 obliquely in a direction coinciding with the longitudinal direction of the substrate and with a part of the widthwise direction thereof protruding from the tip 3b of the lead, and irradiating the upper surface of the lead. Of the light, based on the distance b ₀ between the reflection slit light 24b reflected on the upper surface 3a of the lead and the reflection slit light 24a reflected on the upper surface of the substrate facing the tip of the lead, the floating of the lead A structure configured to inspect for the presence and absence of the fillet based on the presence of the reflected light 23 of the slit light vertically upward with respect to the upper surface of the substrate. A.

According to a second aspect of the present invention, as shown in FIG. 5, in an apparatus for optically inspecting a soldering state of the lead of a semiconductor component whose leads are soldered and surface-mounted on the upper surface of a substrate by a fillet, The slit light 20 is inclined with respect to the substrate 4 in a direction in which the width direction thereof coincides with the longitudinal direction of the lead 3 and with a part of the width direction thereof protruding from the tip 3b of the lead. Of the light projecting means 31 for irradiating and the slit light for irradiating the upper surface of the lead, the reflected slit light 24b reflected by the upper surface 3a of the lead and the reflection reflected by the upper surface of the substrate facing the tip of the lead. Means 34 for inspecting the presence or absence of floating of the lead based on the distance b _{0 from the} slit light 24a,
38, 39, 40, and means 32, 37 for inspecting the presence or absence of the fillet based on the presence or absence of the reflected light 23 of the slit light vertically upward with respect to the upper surface of the substrate. ..

[0018]

The slit light of claim 1 is applied to the substrate in a direction in which the width direction thereof coincides with the longitudinal direction of the lead, and a part of the slit light in the width direction protrudes from the tip of the lead. The configuration of obliquely irradiating acts to make it possible to give information on the floating of the lead and information on the presence or absence of the fillet to the reflected light reflected by the lead portion by one slit light.

The light projecting means according to a second aspect of the present invention functions to make it possible to give the information on the floating of the lead and the information on the presence or absence of the fillet to the reflected light reflected by the lead portion.

[0020]

FIG. 1 shows an embodiment of the soldering lead inspection method of the present invention.

The semiconductor component 1 is surface-mounted as in the case of FIGS. 7 and 8 and the leads 3 are soldered.

In the inspection, as shown in FIG. 1 (A), the sheet-shaped slit light 20 is oriented in such a direction that the width W thereof coincides with the longitudinal direction of the lead 3 and part of the widthwise direction thereof. With 20a protruding from the tips 3b of the leads 3, the substrate 4 is moved in the direction in which the leads 3 are aligned as shown by arrow 21 while the irradiation angle of the substrate 4 to the upper surface 4a is 45 degrees. Do it.

Reference numeral 20b is a portion of the slit light 20 that is applied to the lead 3.

The substrate 4 is moved in the direction of the arrow 21, and in this process, first, the presence or absence of the fillet is inspected, and subsequently, the presence or absence of the lead is inspected, as described below.

When the substrate 4 moves, first, as shown in FIG. 1B, the slit light 20b irradiates the boundary 22 between the lead 3 and the substrate 4.

When the fillet 5 is present, the slit light 2
0b irradiates the fillet 5, and the reflected light 23 goes directly upward, that is, vertically upward with respect to the substrate upper surface 4a, as also shown in FIG.

When the fillet 5 is not present, the slit light 20b is reflected and returned as shown in FIG. 2 (B).

When the slit light 20b irradiates the vicinity of the boundary 22 as shown in FIGS. 2C and 2D.

When the upper surface 4a of the substrate is irradiated, as shown in FIG.
As shown in (C), the side surface 3c of the lead 3 reflects and faces diagonally.

When the side surface 3b of the lead is irradiated, as shown in FIG.
As shown in (D), the light is reflected by the upper surface 4a of the substrate and also faces diagonally.

Therefore, the presence / absence of the fillet 5 can be inspected based on the presence / absence of the reflected light 23 directed right above.

When the substrate 4 is further moved, the slit light 20 irradiates the lead 3 as shown in FIG. 1 (C). Specifically, the slit light 20b irradiates the upper surface 3a of the lead 3, and the slit light 20a irradiates the substrate upper surface 4a facing the tip 3b of the lead 3.

As shown in FIGS. 3A and 3B together,
The slit light 20b is specularly reflected by the lead upper surface 2a, and becomes the reflected slit light 24b that obliquely goes upward. The slit light 20a is specularly reflected by the upper surface 4a of the substrate and becomes a reflected slit light 24a directed obliquely upward.

Numerals 25a and 25b are bright lines that shine upon irradiation.

Here, assuming that the height of the lead 3 is h and the incident angle of the slit light 20 is θ, the reflected slit light 24a.
And the dimension b ₀ between 24b is represented by b ₀ = h / sin θ.

When the lead 31 is floated, the reflection state of the slit lights 20a and 20b is as shown in FIG.
As shown in (B), the reflected slit lights 26a, 26
The dimension between b and b is increased to b ₁ (> b ₀ ). 27
a and 27b are bright lines.

Therefore, the reflected slit light 24a (26a)
The presence or absence of lead floating can be inspected on the basis of the distance between 24b and 26b.

Next, a soldering lead inspection device 30 for performing the above inspection method will be described with reference to FIG.

Reference numeral 31 denotes a slit light projector, which constantly applies the slit light 20 to the lead 3 of the semiconductor component 1 obliquely.

32 is a first television camera,
It is arranged directly above the moving stage 33.

34 is a second television camera,
The TV camera 32 is arranged at a position symmetrical to the projector 31.

A substrate 4 on which the semiconductor component 1 is surface-mounted is mounted on the moving stage 33.

The light projector 31 is always turned on, and the portion of the lead 3 is always illuminated by the slit light 20.

The moving mechanism 36 is driven by a control signal from the control circuit 35, and the stage 33 is intermittently moved in the direction of arrow 21 by the pitch of the leads 3.

The reflected slit light 23 is input to the TV camera 32, and the TV camera 32 images the fillet.

The output of the TV camera 32 is sent to a fillet inspection circuit 37, where the presence or absence of a fillet is inspected.

Further, the reflection slit light 2 is reflected on the TV camera 34.
4a and 24b are incident, and the TV camera 34 emits a bright line 25.
Images of a and 25b (27a and 27b) are obliquely captured.

The image data picked up by the TV camera 24 is
The image is input to the image input circuit 38 at a timing determined by the control signal from the control circuit 35, converted into a digital image of 256 gradations, and stored in the image memory 39.

Further, the image data in the image memory 39 is sent to the lead floating inspection circuit 40, in which the interval between the bright lines is obtained and compared with the reference dimension b ₀ to check the presence or absence of lead floating. To be done.

FIG. 6 shows another example of the soldering lead inspection device 5.
Indicates 0.

The inspection device 60 is capable of inspecting the floating of the leads from both sides and the presence or absence of fillets on both sides of the leads at substantially the same time.

In FIG. 6, parts corresponding to the parts shown in FIG. 5 are designated by the same reference numerals.

TV cameras 34 are provided on both sides of the TV camera 32.
A third television camera 51 and slit light projectors 52 and 53 are provided.

54 and 55 are half mirrors.

Slit light 5 emitted from one projector 52
6 illuminates the lead 3 after being reflected by the half mirror 54, and the reflected slit light 57 reflected here is reflected by the TV camera 3
2 and another reflection slit light 58 is incident on the half mirror 5.
The light passes through 5 and enters the TV camera 34.

Slit light 6 emitted from another projector 53
0 is reflected by the half mirror 55 and irradiates the lead 3, and the reflected slit light 61 reflected here is reflected by the TV camera 3
2 and another reflected slit light 62 is incident on the half mirror 5.
After passing through 4, the light enters the TV camera 51.

The output of the TV camera 32 is sent to the fillet inspection circuit 37, where the both sides of the lead 3 are inspected for the presence of fillets.

[0058] Further, the image data of the TV camera 34, 51 is inputted to the image input circuit 38 at a timing determined by the control signal from the control circuit 35, where it is converted into a digital image, the image memory 39 _-1 Stored separately.

[0059] Image data of the image Momeri 39 in _-1 is sent to the read height detection circuit 40, whether the lead float is examined.

[0060]

As described above, according to the first aspect of the present invention, the operation of switching the light emission is not necessary, and the inspection of the presence or absence of the lead floating and the inspection of the presence or absence of the fillet can be performed substantially at the same time. .. As a result, the time required for the inspection can be reduced to about half that of the conventional method.

According to the second aspect of the present invention, basically only one light projecting means is required, no means for switching the light projecting means is required, and the structure can be simplified.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a soldering lead inspection method of the present invention.

FIG. 2 is a diagram showing a state of reflection during fillet inspection.

FIG. 3 is a diagram showing a state of reflection during a lead floating inspection.

FIG. 4 is a diagram showing a state of reflection when a lead is floated.

FIG. 5 is a diagram showing an embodiment of a soldering lead inspection device of the present invention.

FIG. 6 is a diagram showing another embodiment of the soldering lead inspection apparatus of the present invention.

FIG. 7 is a diagram illustrating a conventional soldering lead inspection method.

FIG. 8 is a plan view of a mounted state of QFP.

[Explanation of symbols]

1 surface mount semiconductor component (QFP) 2 main body 3 lead 3a upper surface 3b tip 3c side surface 4 substrate 4a upper surface 5 fillet 20 slit light 20a portion protruding from the lead 20b portion applied to the lead 21 substrate movement arrow 22 and the substrate and Boundary 23 Reflected light vertically upward from the fillet 24a, 26b Reflected slit light on the upper surface of the lead 24b, 26b Reflected slit light on the upper surface of the substrate 25a, 25b, 27a, 27b Bright line 30,50 Solder lead inspection device 31,52, 53 slit light projector 32 first television camera 33 moving stage 34 second television camera 35 control circuit 36 moving mechanism 37 fillet inspection circuit 38 image input circuit 39, 3 _-1 image memory 40 lead floating inspection circuit 51 third Television camera 54,55 Half mirror

Claims (2)

[Claims] 1. A method of optically inspecting a soldering state of a lead of a semiconductor component surface-mounted on an upper surface of a substrate by filling a lead with a fillet, wherein slit light (20) is applied in a width direction. Lead (3) above
In a direction coinciding with the longitudinal direction of the lead wire, and with a part of the widthwise direction thereof protruding from the tip (3b) of the lead, the substrate (4) is irradiated obliquely to expose the upper surface of the lead. Of the slit light to be radiated, the reflected slit light (24
The presence or absence of floating of the lead is inspected based on the interval (b ₀ ) between the b) and the reflection slit light (24a) reflected on the upper surface of the substrate facing the tip of the lead, and the slit light ( 20) A soldering lead inspection method characterized by inspecting the presence / absence of the fillet based on the presence / absence of light (23) reflected vertically upward with respect to the upper surface of the substrate. 2. An apparatus for optically inspecting a soldering state of a lead of a semiconductor component surface-mounted on the upper surface of a substrate by filling a lead with a fillet, wherein slit light (20) is applied in the width direction. Lead (3) above
A light projecting means (31) for obliquely irradiating the substrate (4) in a direction coinciding with the longitudinal direction of the substrate and with a part of the widthwise direction thereof protruding from the tip (3b) of the lead. Of the slit light irradiating the upper surface of the lead, the reflected slit light (24
Means (3) for inspecting the presence or absence of floating of the lead based on the interval (b ₀ ) between b) and the reflected slit light (24a) reflected on the upper surface of the substrate facing the tip of the lead.
4, 38, 39, 40) and means for inspecting the presence or absence of the fillet based on the presence of reflected light (23) of the slit light (20) vertically upward with respect to the upper surface of the substrate. ) Is a soldering lead inspection device.