JP3444228B2 - Semiconductor device lead inspection device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead inspection apparatus, and more particularly to an apparatus for inspecting a lead molding state of a semiconductor device.

[0002]

2. Description of the Related Art With the surface mounting and miniaturization of semiconductor devices, there is an increasing need for highly accurate visual inspection of lead molding conditions. Above all, it is necessary to provide a simple appearance inspection device which can be inlined in the process and has a structure that does not cause a defect in the lead by inspection.

A conventional semiconductor device lead inspection apparatus of this type is described in Japanese Patent Laid-Open No. 7-55441. The lead inspection device described in the publication will be described with reference to FIG. As shown in FIG. 1, the conventional lead inspection apparatus has a mounting table 1 on which the leads 2 of the semiconductor device 1 are mounted.
0, a prism 90 mounted inside the table 10 for reflecting the image of the illumination light from the illumination light source 4 by the lead 2 downward in the figure, and an image pickup device 7 for receiving the projection light. Has been done.

In this inspection apparatus, the shadow of the illumination light from the illumination light source 4 applied to the side surface of the lead 2 of the semiconductor device 1 is guided downward by the prism 90 in the figure, and the semiconductor device 1
This is a device for reading with an imaging device 7 installed on the lower surface and detecting floating of the leads and coplanarity.

[0005]

However, with the inspection apparatus described in the above-mentioned publication, it is difficult to apply the inspection to a device having no standoff by lead molding. In order to solve this, the inspection apparatus described in Japanese Patent Laid-Open No. 7-98216 can be applied to an inspection even for a device having no standoff.

The inspection apparatus described in the publication is shown in FIG.
As shown in FIG. 0, the mounting table 10 on which the leads 2 of the semiconductor device 1 are mounted, and the prism 90 for reflecting the image of the illumination light from the illumination light source (not shown) by the leads 2 upward in the figure.
And an imaging device 7 for receiving this projection light.

However, in the inspection apparatus of the same figure, when the semiconductor device 1 does not have a stand-off by lead molding such as a flat lead package, the mounting table 10 and the flat portion mounting surface of the lead 2 come into contact with each other. Therefore, there is a drawback that it is difficult to identify the lead in the image pickup device 7.

The present invention has been made to solve the above-mentioned drawbacks of the prior art, and an object thereof is to provide a lead inspection apparatus capable of surely performing a lead inspection on a flat lead package.

[0009]

A lead inspection apparatus according to the present invention relates to a semiconductor device which is surface-mounted on a substrate by electrically connecting a lead drawn from a package and a wiring on the substrate. a lead inspection system, a light irradiating means for irradiating light to the first and second main surfaces of the lead, an imaging unit for imaging the lead the light is irradiated from the pull-out direction, the first of the lead And the second lord
Light reflected by each surface is reflected light
And a light reflecting unit for causing the image pickup unit to pick up an image, and the lead is inspected according to the image pickup content of the image pickup unit.

[0010]

The light reflecting means is provided in the vicinity of the first main surface and in the vicinity of the second main surface of the lead, respectively, to allow the light to the lead to pass therethrough and to allow the light from the lead to be on the imaging means side. The first and second beam splitters that reflect the light beam are reflected. An image display means for displaying on the same screen an image of the lead taken by the image pickup means in the pull-out direction and an image of the first and second main surfaces of the lead taken by the light reflecting means and the image pickup means. Is further included.

[0012]

Still another lead inspection apparatus according to the present invention is
A lead inspection apparatus for a semiconductor device which is surface-mounted on the substrate by electrically connecting a lead drawn from the package and a wiring on the substrate, which is an image pickup method for imaging the package from the upper surface direction. Means, a first light source, and a first beam that reflects the light from the light source to irradiate the first main surface of the lead, allows the reflected light from the first main surface to pass, and guides the light to the imaging means. A splitter, a second light source, and a second beam that allows light from the light source to pass therethrough, irradiates the second main surface of the lead, reflects reflected light from the second main surface, and guides the light to the imaging means. The splitter and the second
And a third beam splitter for guiding the reflected light from the beam splitter and the reflected light from the side surface of the lead to the image pickup means.

In short, this lead inspection apparatus illuminates from the upper and lower surfaces of the semiconductor device leads in a semiconductor device in which lead terminals are drawn out flat from the resin portion, for example, a power mini-mold SOT-89 package, and leads flat. This is a lead appearance inspection device capable of inspecting a vertical bending with respect to a semiconductor device mounting surface such as lead floating and flipping up by imaging a reflection from a semiconductor device lead side.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described with reference to the drawings. In each drawing referred to in the following description, the same parts as those in the other drawings are designated by the same reference numerals.

FIG. 1 is a block diagram showing an embodiment of a lead inspection apparatus according to the present invention. In the figure, the inspection apparatus includes a light source 3 for irradiating the lead 2 of the semiconductor device 1 with light on the upper surface of the flat portion, a light source 4 for irradiating light on the lower surface of the flat portion of the lead 2, and illumination from the light source 3. A beam splitter 5 that transmits light and reflects the reflected light from the flat portion of the lead 2 due to the illumination light of the light source 3 toward the imaging device 7 side.
And a beam splitter 6 that transmits the illumination light from the light source 4 and reflects the reflected light from the flat portion of the lead 2 due to the illumination light of the light source 4 toward the imaging device 7 side, and the semiconductor device device to be inspected during the inspection. 1 and a mounting table 10 for holding 1.

The present inspection apparatus also includes an image pickup device 7 for picking up the reflected light from the flat portion of the lead 2 and the reflected light from the upper and lower surfaces of the flat portion of the lead 2 reflected by the beam splitters 5 and 6, respectively. An image processing device 8 that performs a predetermined image process on the result and a monitor 9 that displays the image after the image process on the screen are configured.

This device has a semiconductor device having a shape in which lead terminals are drawn out flat from the resin portion, that is, a lead drawn out in a plane substantially the same as the bottom surface of the package. By being electrically connected to the wiring, it can be applied to a semiconductor device surface-mounted on a substrate. For example, the leads of a power mini mold SOT (small outline) -89 package can be inspected.

Here, the beam splitters 5, 6 and the light source 3,
4 is a combination of those having different polarization directions. That is, as shown in FIG. 2, the beam splitter 5 transmits the illumination light from the light source 3, and the reflected light from the flat portion of the lead 2 to the light source 3 side is reflected to the imaging device 7 side. As a result, the light on the optical path A to the imaging device 7 side is led out. At this time, the component not reflected by the lead 2 passes through the beam splitter 6 and becomes the light on the optical path C.

Further, the reflection of the illumination light from the light source 3 toward the image pickup device 7 side by the beam splitter 6 is minimized. The beam splitter 5 transmits the illumination light from the light source 4 and minimizes the reflection toward the imaging device 7 side.

Returning to FIG. 1, the output signal of the image pickup device 7 is subjected to image processing by the image processing device 8 and then displayed on the monitor 9 as an image. The image processing device 8 is assumed to be capable of binarizing the image pickup signal of the image pickup device 7, detecting the degree of matching (matching) with a normal signal registered in advance, and measuring the distance between the matching patterns.

Next, an image pickup example of the semiconductor device lead inspection apparatus of the present invention will be described. Here, a case will be described where the semiconductor device having the configuration of FIG. 1 is used to inspect, for example, the semiconductor device having the one-side four-pin configuration shown in FIG. Figure 3 (a)
Is a bottom view of the semiconductor device, and FIG. 6B is a side view of the semiconductor device.

Referring to FIG. 1A, the semiconductor device 1
Has a long side length of 5.0 on the bottom side of the package.
8 [mm] and the lead pitch is 1.27 [mm]. The width of the lead is 0.4 [mm] and the length of the lead is 0.6 [mm]. Then, as shown in FIG. 6B, a lead having a thickness of 0.15 [mm] is drawn out in the same plane as the bottom surface of the package. The semiconductor device 1 is mounted on the surface of the substrate by electrically connecting the leads and the wiring, electrodes, etc. on the substrate (not shown).

When the semiconductor device 1 having the shape shown in FIG. 3 is inspected, the image captured by the image pickup device 7 is as shown in FIG. The images obtained in the imaging example shown in FIG. 3A are the lead flat portion top surface image 31 a derived by reflecting the image seen from above the semiconductor device 1 by the beam splitter 5, and the reflection from the lead 2. It is composed of a lead floating detection image 30a due to light and a lead flat portion lower surface image 32a derived by reflecting the image seen from below the semiconductor device 1 by the beam splitter 6. Here, it is assumed that there is no inversion / rotation of the lens incident image by the optical system attached to the image pickup device 7 or the image processing device 8.

Referring to the flat portion top surface image 31 of the lead 2 of the semiconductor device 1, the lead bend, the flat portion shape,
It is possible to inspect for scratches and plating. As shown in FIG. 5 (a), the lead bending is caused by the center C0 of the root of the lead 2 on the mold side and the center C1 of the tip of the lead.
It can be determined by measuring the distance ΔL between and. The distance is measured by detecting a pattern similar to the matching pattern registered in advance in the image processing device 8 from the output image of the image pickup device 7.

With respect to the semiconductor device 1, the allowable range of the distance ΔL is set in advance depending on the mounting target. Then, if the measured value of the distance ΔL is outside the allowable range, the image processing device 8 determines that the product is defective.

Further, a flaw or chip on the lead surface is determined by referring to the binarized signal output from the image pickup device 7. In this case, the standard area range (the number of pixels) of the flat portion of the lead 2 that has been measured in advance using a non-defective product is set, and the image processing device 8 determines that the lead area to be inspected is a defective product. Judge that there is.

Similarly, the bottom surface image 32 of the flat portion of the lead 2 is shown.
Refer to, scratches on the flat portion of the semiconductor device mounting surface side,
The plating condition can be inspected.

On the other hand, by referring to the lead floating detection image 30, it is possible to inspect the floating / jumping state of the lead flat portion. For example, as shown in FIG. 2, when the flat portion is bent to the mounting surface side (lower side in the drawing), a component to the image pickup device 7 side is generated in the reflected light from the light source 3. Here, for example, when the length of the lead 2 is L and the bending angle is θ, a reflected image having a height proportional to L × sin θ can be obtained. Similarly, when the lead 2 is bent to the side opposite to the mounting surface (upper side in the drawing), the reflected light from the light source 4 is generated on the imaging device 7 side.

The image pickup device 7 is derived as shown in FIG.
The image captured in (1) is binarized by the image processing device 8 to become an image as shown in FIG. In the same figure (b), each image 30a-32 of the same figure (a).
A lead upper surface image 31b, a lead lower surface image 32b, and a lead floating detection image 30b corresponding to a are shown.
In addition, H in the figure is a mold bottom reference line of the semiconductor device.

In the figure (b), (1) and (4) show a state of bending upward, and (2) shows a state of bending downward. (3) in the figure shows a normal state without bending.

Here, the allowable range of floating and flipping up of the lead 2 is defined by the amount of solder on the board side (solder height) during mounting. When inspecting the semiconductor device shown in FIG. 3, if the solder height is 30 [μm], the floating height is 30
The image processing device 8 is required to have a resolution capable of detecting a length (number of pixels) corresponding to [μm]. For example, the resolution of a general image processing device is 512 × 512 pixels for image pickup, and the total length of the semiconductor device shown in FIG. 3 is 5.08.
If it is [mm], a pixel resolution of about 10 [μm] per pixel can be obtained.

In this case, the lead float / rebound allowable value 3
Since 0 [μm] corresponds to 3 pixels, it can be sufficiently detected. For the semiconductor device having a lead pitch of 1.27 [mm] when the above image processing device 8 is used, a maximum of 16 pins can be detected. Can be inspected.

By the way, in the lead 2 of the semiconductor device 1 shown in FIG. 3, one side 4 is provided on the lower side (mounting surface side).
The leads of the book must be bent in the same condition (coplanarity). For example, if three leads bend downward (mounting surface side) and one lead bends upward (opposite the mounting surface), each lead bends upward even if it is within the allowable range. There is a possibility that one lead cannot be connected to the wiring on the board during mounting.

In the embodiment shown in FIG. 1, the positional relationship between the image pickup apparatus 1 and the mounting table 10 is fixed, and therefore, FIG.
The mold bottom reference shown in the binarization example of (b) is set in the image processing device 8, and lead floating / variation with respect to the reference is determined. For example, the allowable range of variation when the solder height is 30 [μm] is 30 [μm].

Further, the leads of the semiconductor device 1 are formed in a form called a lead frame in which a plurality of leads are formed together with an island portion for mounting a semiconductor pellet and the like. Then, in general, the semiconductor element (pellet) is mounted, bonded, and sealed with resin in a lead frame state, and is cut into individual sides at the final stage of assembly. As this cutting method, there is known a method such as laser cutting which has little influence on the cut cross section. However, generally, cutting by shearing using a mold is often used. When this mold is used, burrs on the cross section and sagging of the end face may occur.

FIG. 6 shows an example of burrs. That is, as shown in the figure, the lead end 22 which is a cut surface at the time of cutting is warped upward in the figure to be in a burr state. On the lead end surface having such burrs and sags, there is a possibility that reflection of the illuminations 3 and 4 may occur even though the lead 2 itself has no vertical bending on the upper surface 20 and the lower surface 21 of the lead flat portion. is there. That is, the light from the light source 3 may be reflected by the lead end 22 toward the image pickup device 7 as in the optical path 40 in the figure.

However, the reflected light due to burr and sag has a higher reflection luminance in the direction of the image pickup device 7 than the reflected light due to the lead bending. Therefore, by removing the high-luminance side and the low-luminance of the imaging result in the imaging example shown in FIG. 4A, the lead 2 can be obtained as in the binarization example shown in FIG. It is possible to derive only the actual reflected light of the flat portion of the.

In this structure, the upper and lower surfaces of the lead 2 of the semiconductor device 1 to be inspected are illuminated by the light sources 3 and 4 on the upper and lower surfaces of the flat portion of the lead 2, and the reflected light from the flat portion is transmitted to the image pickup device 7. To image. By doing so, the bending of the lead 2 in the vertical direction is detected. Further, the reflection of the illumination light from the light sources 3 and 4 from the flat portion of the lead 2 is reflected by the beam splitters 5 and 6 to the imaging device side, so that the lead 2 can be detected in the vertical bending and at the same time, the flat portion can be prevented from being scratched or bent. Can be inspected. In contrast to the normal shape shown in FIG. 5B, the lead missing state as shown in FIG.
It is possible to detect the lead scratch state as shown in (d).

At the time of inspection, the semiconductor device 1 is set on the mounting table 10 so as to hold the bottom surface of the mold. The output of the imaging device 7 is displayed on the monitor 9 after being processed by the image processing device 8. According to this configuration, it is possible to inspect the bending of the leads in the vertical direction with the bottom surface of the mold as a reference without damaging the leads.

As described above, according to the present apparatus, a plurality of angles are used for conducting the lead inspection of the semiconductor device, particularly the lead floating, the lead bending, and the flat portion shape of the lead defects for the flat lead package. It is possible to take a lead image from a single image pickup device. Further, in this apparatus, the semiconductor device to be inspected is held not by the leads but by the lower surface of the mold, and therefore, bending of the leads due to the inspection does not occur. Further, since the inspection from a plurality of directions can be simultaneously performed by one camera, the cost of the apparatus can be reduced.

In the present apparatus, the image of the lead 2 taken by the image pickup device 7 from the pull-out direction and the image of the upper surface and the lower surface of the lead 2 are displayed on the same screen of the monitor 9. The inspection can be done easily.

In the example shown in FIG. 1, the beam splitters 5 and 6 and the image pickup device 7 are formed on only one side of the lead of the semiconductor device. It is obvious that all the leads can be inspected at the same time by mounting the beam splitter and the image pickup device on all sides in the lead-out direction.

Next, another embodiment of the present invention will be described. When the distance between the flat portion of the lead 2 and the beam splitter is long as in the embodiment of FIG. 1, an image optical path difference to the image pickup device 7 may occur. Therefore, FIG. 7 shows an example in which the direct reflection light from the lead flat portion is subjected to optical path correction in order to correct the optical path. In the figure, an optical path correction plate 8 is provided between the lead 2 and the imaging device 7. By adding this optical path correction plate 8, even if the distance between the flat portion and the beam splitter is long, the light from the lead 2 is corrected so as to be guided to the imaging device 7.

Further, another embodiment of the present invention will be described. FIG. 8 shows an example in which the image pickup device is set on the upper surface side of the semiconductor device in order to inspect the resin surface state of the semiconductor device 1. In the figure, the difference from the configuration of FIG. 1 is that the beam splitter 11 is added and the positions of the light source 3 and the imaging device 7 are changed. In the figure, the light source 3 is set on the side of the lead-out side surface of the semiconductor device 1, and the illumination light from the light source 3 is reflected by the beam splitter 5 toward the flat portion side of the lead 2. The light reflected from the lead flat portion is transmitted through the beam splitter 5. By doing this, all the leads can be inspected by one camera.

In short, in this embodiment, the image pickup device 7 is provided at a position for picking up an image of the package from the upper surface direction, and the light from the light source 3 is reflected to irradiate the upper surface of the flat portion of the lead 2 and the reflected light is allowed to pass through. A beam splitter 5 that guides the image to the imaging device 7 is provided. Further, in the present embodiment, the beam splitter 6 that allows the light from the light source 4 to pass through, irradiates the lower surface of the flat portion of the lead 2 and reflects the reflected light to the imaging device 7, and the reflected light from the beam splitter 6 and The imaging device 7 reflects the reflected light from the side surface (end surface) of the lead 2.
And a beam splitter 11 that guides the beam.

With this structure, the resin surface state of the semiconductor device 1 can be inspected at the same time when the leads are inspected.

[0048]

As described above, according to the present invention, by picking up an image of the lead irradiated with light from the direction of pulling out the lead, the lead inspection of the semiconductor device, especially the lead floating among the lead defects for the flat lead package, In the inspection of lead bending and flat portion shape, there is an effect that it is possible to inspect lead images from a plurality of angles by using only one imaging device. Further, since the semiconductor device to be inspected is held on the bottom surface of the mold instead of the lead,
There is an effect that lead bending is not caused by the inspection. Further, there is an effect that the inspection from a plurality of directions can be simultaneously inspected by one camera, and the cost reduction of the apparatus can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a lead inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing an optical path of irradiation light from a light source in a bent lead state.

3A is a bottom view of the semiconductor device, and FIG. 3B is a side view of the semiconductor device.

FIG. 4A is a diagram showing an image picked up by an image pickup device;
(B) is an image obtained by being binarized by the image processing apparatus.

5A is a diagram showing a bent lead state, FIG. 5B is a diagram showing a normal shape, and FIG. 5C is a diagram showing a lead missing state;
(D) is a diagram showing a lead scratch state.

FIG. 6 is a diagram showing an example of lead burr.

FIG. 7 is a diagram showing a configuration of an example in which a function of correcting an optical path of direct reflected light from a lead flat portion is added.

FIG. 8 is a diagram showing a configuration of an embodiment in which an image pickup device is set on a top surface side of a semiconductor device.

FIG. 9 is a diagram showing a configuration of a conventional lead inspection device.

FIG. 10 is a diagram showing the configuration of another conventional lead inspection apparatus.

[Explanation of symbols]

1 Semiconductor device 2 leads 3,4 light source 5,6,11 Beam splitter 7 Imaging device 8 Optical path correction plate 9 monitors 10 table

Continuation of front page (56) Reference JP-A-60-73306 (JP, A) JP-A-5-231835 (JP, A) JP-A-7-98216 (JP, A) JP-A-10-153413 (JP , A) JP 62-194403 (JP, A) JP 3-15707 (JP, A) Actual Kaihei 6-56846 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) G01B 11/00-11/30 H01L 21/66 G01N 21/88

Claims (5)

(57) [Claims] 1. A lead inspection apparatus for a semiconductor device surface-mounted on a substrate by electrically connecting a lead drawn from a package and a wiring on the substrate, the first lead of the lead. And a light irradiation means for irradiating the second main surface with light, an image pickup means for picking up an image of the lead irradiated with the light from the pull-out direction , and the first and
The light reflected by the second main surface is reflected and
Light reflection means for causing the image pickup means to pick up reflected light
And a lead inspection apparatus for inspecting the lead according to the image pickup content of the image pickup means. 2. The light reflecting means is provided in the vicinity of the first main surface and in the vicinity of the second main surface of the lead, respectively, to allow the light to the lead to pass therethrough and to allow the light from the lead to be on the imaging means side. The lead inspection apparatus according to claim 1 , wherein the lead inspection apparatus includes first and second beam splitters that reflect the light beam. 3. An image obtained by picking up the lead from the drawing direction by the image pickup means and an image obtained by picking up the first and second main surfaces of the lead by the light reflecting means and the image pickup means are displayed on the same screen. The lead inspection apparatus according to claim 1, further comprising an image display means. 4. A lead inspection apparatus for a semiconductor device which is surface-mounted on a substrate by electrically connecting leads drawn from the package and wiring on the substrate, wherein the package has an upper surface. An image pickup means for picking up an image from a direction, a first light source, and a light from the light source is reflected to irradiate the first main surface of the lead and the reflected light from the first main surface is passed to the image pickup means. A first beam splitter that guides the light, a second light source, and light from the light source is passed through to irradiate the second main surface of the lead, and reflected light from the second main surface is reflected to the imaging means. A second beam splitter that guides the reflected light from the second beam splitter and a reflected light from the side surface of the lead to the imaging unit.
And a beam splitter. 5. An image display means is further included for displaying on the same screen an image of the upper surface of the package captured by the image capturing means and an image of the light guided by the first to third beam splitters. The lead inspection apparatus according to claim 4 .